Music Therapy

Professor Yankee 11/19/12 Music Therapy Why do people use this type of therapy exactly? Well music has been used as medicine for thousands of years and there's a growing field of health care known as music therapy, which uses music to heal. Those who practice music therapy find benefits in using it to help cancer patients, children with ADD, and others, and even hospitals are beginning to use music therapy to help with pain management, to help ward off depression, to promote movement, to calm patients, to improve communication, to ease muscle tension, and for many other benefits that music and music therapy can bring.A lot of people don't understand what kind of therapy this is, people have different assumptions about it but it is a real profession that takes a bachelor music degree. Music therapists work with a variety of physical, emotional, and psychological symptoms. It is often used in cancer treatment to help reduce pain, anxiety, and nausea caused by chemotherapy. Some people believe music therapy may be beneficial to the health care of children with cancer by promoting social interaction and cooperation.There is evidence that music therapy can reduce high blood pressure, rapid heart beat, depression, and sleeplessness. There are no claims music therapy can cure cancer or other diseases, but medical experts do believe it can reduce some symptoms, aid healing, improve physical movement, and enrich a patient’s quality of life. Ancient Greek philosophers believed music could heal both body and mind, Native Americans used singing and chants to heal millennia. More formal approaches begin in World War two when hospitals started using music to help soldiers with shell shock.In 1944, Michigan State University established the first music therapy degree program in the world. Music therapists design music sessions for individuals and groups based on their needs and tastes. Some aspects of music therapy include making music, listening to music, writing songs , and talking about lyrics. Music therapy may also involve imagery and learning through music. It can be done in different places such as hospitals, cancer centers, at home, or anywhere people can benefit from its calming or stimulating effects. The patient does ot need to have any musical ability to benefit from music therapy. Most peoples reaction to music is a burst of energy upon hearing an upbeat song or a sense of calm during a soothing classical piece. Music therapy uses this connection between music and mood. It has also been shown to lower amounts of the hormone cortisol, which becomes elevated under stress, and to increase the release of endorphins, the body’s natural â€Å"feel-good† hormones. Researchers have found that music therapy, when used with anti-nausea drugs for patients receiving high-dose chemotherapy, can help ease nausea and vomiting.A number of clinical trials have shown the benefit of music therapy for short-term pain, including pain from can cer. Music therapy works by stimulating parts of the brain that are associated with music in a person with Alzheimer’s disease, the section of the brain that allows direct recall of memories is damaged. Musical memories, however, are associated not only with the music itself but also with the circumstances surrounding the musical experience. Listening to music can indirectly stimulate the recall of memory fragments that otherwise could not be retrieved.The ability to retrieve some memories can be comforting to people with dementia. In a different manner, music therapy can assist those with Parkinson’s disease. In a person with Parkinson’s, the part of the brain that organizes thoughts and movements into action is damaged. Music with a strong, rhythmic beat can stimulate motor control, movement and coordination. Studies show that gait training that uses music improves walking speed and coordination for people with Parkinson’s.In general, music therapy done under the care of a professionally trained therapist has a helpful effect and is considered safe when used with standard treatment. Musical intervention by untrained people can be ineffective or can even cause increased stress and discomfort. Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences. Besides that there are no real risks or dangers to using music to heal. But how far can music heal you?There was a study that examined 200-300 patients with diabetes participants in a three year study starting this April. Although we do know that music can help vasculature, mental states and mood, there is little to no evidence to suggest that music therapy will help the outcome of diabetes. Perhaps there will be some miraculous benefit for patients suffering from diabetes to engage in extreme music therapy, however previous research indicates that it is not the music itself that determines the benefits, b ut the emotional responses to the music that is the key.Even though there is little evidence to support that music will help diabetes. Scientific studies have shown the value of music therapy on the body, mind, and spirit of children and adults. Researchers have found that music therapy, when used with anti-nausea drugs for patients receiving high-dose chemotherapy, can help ease nausea and vomiting. A number of clinical trials have shown the benefit of music therapy for short-term pain, including pain from cancer.Some studies have suggested that music may help decrease the overall intensity of the patient’s experience of pain when used with pain-relieving drugs. Music therapy can also result in a decreased need for pain medicine in some patients, although studies on this topic have shown mixed results. Studies have shown that students who take music lessons have improved IQ levels, and show improvement in nonmusical abilities as well. Other studies have shown that listening to music composed by Mozart produces a short-term improvement in tasks that use spatial abilities.Studies of brain circulation have shown that people listening to Mozart have more activity in certain areas of the brain. This has been called the â€Å"Mozart effect. † Although the reasons for this effect are not completely clear, this kind of information supports the idea that music can be used in many helpful ways. What can be improved ? Verbal & nonverbal communication, Gross and fine motor movement,Range of motion, Relaxation techniques, Anger management skills, Expression of emotion, Sensory integration, Academic skills, and Leisure skills. We use music to make your life better.Whether you need help socially, cognitively, physically, emotionally, or developmentally, music can help you get better and music therapists trained on how to do that. What’s more interesting, though, is why it works. When used properly, music can be an incredibly powerful treatment tool. And not just because it’s fun, relaxing, and motivating, but because music has a profound impact on our brains and our bodies. First off music is the core function of our brains, we have physiologic responses to music,Our brain is primed early on to respond to and process music.Every time your breathing quickens, your heart-rate increases, or you feel a shiver down your spine, that’s your body responding physiologically to music. Qualified music therapists can use this to help stimulate a person in a coma or use music to effectively help someone relax. Music often has a predictable steady beat, organized phrases, and a structured form. Most country/folk/pop/rock songs, they’re often organized with a verse-chorus structure. They’re organized in a way that we like and enjoy listening to over and over again.Even sound waves that make up a single tone or an entire chord are organized in mathematical ratios–and our brains really like this predictability an d structure. Music is in our everyday lives, we hear it in the store, at school, church, music is part of our thoughts, how we speak, even when there's none around we can still it in our heads. With all these benefits that music can carry, it's no surprise that music therapy is growing in popularity. Many hospitals are using music therapists for pain management and other uses. Music therapists help with several other issues as well, including stress.While music therapy is an important discipline, you can also achieve many benefits from music on your own. Music can be used in daily life for relaxation, to gain energy when feeling drained, for catharsis when dealing with emotional stress, and in other ways as well. Music therapy has been proven to be an effective form of therapy in a variety of areas for a multitude of ailments. However, there is still much more theorizing, discussion, and research that needs to be done in this area, and that fact makes it all the more interesting.Thr ough technological advances and constantly evolving musical styles as well as cross-cultural influences, this is one form of therapy that will never cease to be innovative and topical. Hopefully, researchers will continue to treat this topic as a serious area of psychology and one that deserves to be molded into a more scientific pedagogy through advancement and refinement of research and therapeutic techniques. I believe there is much more to be discovered about music and its effect on humanity.

Elizabeth Bennet in “Pride and Prejudice” Essay

Individuality refers to the character or qualities which distinguish one person from another. Ones uniqueness constitutes a strong distinctiveness in his/her character. Thus, when this sense of character is juxtaposed against the concept of individuality, the mutual association results in the inherent emergence of a persons true identity. Although the distinguishing of separate individuals personalities remains admired in todays society, there existed a time in which the pursuit of uniqueness in character and personality was discouraged. This held especially true for women in Regency England in the 1800s. A woman in this time period, respectively the setting of Jane Austens Pride and Prejudice, endured numerous pressures and overwhelmingly strict rules from societal norms in order to obtain proper placement in society. Women of the time most importantly should marry, and marry well, primarily to obtain the substantially vital possession of an exceptional reputation, and also to support their family and retain a good name. In addition, women held considerably inferior societal positions to men, having strict sociable allowances to only partake in balls, dances, and dinners. These contribute to a woman acquiring a greater extent of connections, which in turn increases their chance of marrying well. However, Jane Austen does in fact present a character that ultimately triumphed over the particular stereotype of women in pursuit of her own ideals. Elizabeth Bennet, the protagonist and heroine of Pride and Prejudice, conveys a powerful sense of independence, remains very outspoken of her views, and a reason for marrying which all contradict the stereotypical woman of the time. Elizabeth is an extremely atypical female for her time, for she invariably refuses to allow the loss of her individualism and pe rsonal identity in a society which encourages women to do exactly that. Initially, Elizabeths attitude of independence induces her to act on the instinct of her unique ideals; her sense of self reliance eventually causing a mass of pride and prejudice to formulate around her thoughts and dialogue. No, indeed I do not wish to avoid the walk, for the distance is nothing when one has a motive; only three miles (28). Elizabeth acts in direct defiance towards her mother, and even though she expects to create a negative first impression, her own concerns (such as the well-being of her sister), prevail as a top priorities in her independent mind. She also walks alone,  signifying the scarcity of independence exhibited by women of the 1800s, particularly towards situations that could potentially threaten ones reputation, such as Elizabeths walk in the mud. To such perseverance in willful self-deception Elizabeth would make no reply, and immediately and in silence withdrew, determined, that if he persisted in considering her repeated refusals as flattering enco uragement, to apply to her father, whose negative might be uttered in such a manner as to be decisive, and whose behavior at least could not be mistaken for the affectation and coquetry of an elegant female (91). In the thoroughness of Elizabeths dialogue, the author presents a tone of irritancy, for the protagonists self reliance on her own opinions could not sway Mr. Collins foolish assumptions. Through Elizabeth, the author also expresses heartily disdain of the inferiority of female roles of the time period, depicted by the occurrence of Mr. Bennet having to explain Elizabeths feelings instead of her effectively conveying them herself. I am only resolved to act in that manner, that will, in my own opinion, constitute my happiness, without reference to you, or to any person wholly unconnected with me (294). Essentially, this statement of Elizabeths to Lady Catherine demonstrates her fierce independence. She specifically states that her happiness is the only factor in the governance of her actions. Her self reliance and her own opinions create an independence which allows her to disregard the judgments of others no matter their social standing. Elizabeths independent mindset constitutes a v ery opinionated personality and character, which becomes exposed through remarkable dialogue. Subsequently, Elizabeths outspoken nature causes consequently different interactions with people through dialogue, than would traditionally occur with a stereotypical female. I talked about the dance, and you ought to make some sort of remark on the size of the room or the number of couples (76). Normally, a person would not point out the faults in their dance partners manners. However, Elizabeths outspoken nature allows her to mock an individual of higher social consequence for his discomfited behavior. This interaction presents a fine example of Jane Austens ironic humor. Darcy remains silent at the ball in order to remain socially superior in his mind. However, he receives a lecture from a member of lower social standing, a woman no less, concerning manners and formal protocol. From the very  beginning— from the first moment, I may almost say— of my acquaintance with you, your manners, impressing me with the fullest belief of your arrogance, your conceit, and your selfish disdain of the feelings of others, were such as to form the groundwork of disapprobation on which succeeding events have built so immovable a dislike; and I had not known you a month before I felt that you were the last man in the world whom I could ever be prevailed on to marry (159). With none of the traditional politeness or subservience of her gender, Elizabeths reveals her unrelenting will to speak her mind in a situation of anger and in support of her feelings, which consequently humiliates Darcy. He became a victim to something virtually unheard of for a man of his social stature: an outspoken woman. Darcys formal and polite exit reinforces the importance that high society places in constant manners and obedience of formal protocol, portraying his now tentatively preserved sense of superiority. Lady Catherine seemed quite astonished at not receiving a direct answer (139). Elizabeth upon this instance speaks her mind in an incredibly daring manner. It seems that Elizabeth became the first individual ever to address Lady Catherine in that way, an exceptionally audacious stunt considering the old widows possession of so much dignified impertinence. Along with her outspoken behavior, Elizabeths marital ideals present themselves as the exact opposite of views exp ected to be held by women at the matrimonial age in Pride and Prejudice. Furthermore, most women of Jane Austens time period viewed marriage as the ultimate goal in life, a wondrous aspiration to be attained for comfort, materialism, and social stature; Elizabeth exclusively declines to accept these ideals as governance for her own actions. It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife (1). This initial statement of Jane Austens masterpiece offers a miniature sketch of the entire plot, which concerns itself with the pursuit of single men in possession of a good fortune by various female characters. The preoccupation with socially advantageous marriage in nineteenth-century English society manifests itself here, for in claiming that a single man must be in want of a wife, the narrator reveals that the reverse is also true: a single woman, whose socially prescribed options are quite limited, desires a husband. However, Elizabeth criticizes the  advantages and consequence of marriage in her society, such as whether or not one holds respect for their lifes partner, negatively portrayed by her parents. Elizabeth fortifies these ideals in her declaration that â€Å"I am determined that nothing but the very deepest love will induce me into matrimony† (38). Due to the fact that Elizabeths extreme opinion of marriage comes as a response to Janes similar view, implications arise that Elizabeths point of view does not remain exclusively unique. However, closer examination of Janes character reveals that although love intrigues her aspirations, she would easily and appropriately succumb to societal expectations. Elizabeths outlook sets her far apart from the majority of women at the time, her position expressing that only love constitutes acceptable reason to marry. You could not make me happy, and I am convinced I am the last woman in the world who would make you so (102). Elizabeth adequately proves her profoundly unique views of matrimony by the adamant refusal of two separate but exceedingly suitable marriage proposals. In Elizabeths position, to not marry Mr. Collins would put her in a very precarious situation financially, condemning all her family to certain disaster, and to denounce tradition for the sake of her principles seems foolhardy but also requires a fair amount of mustered courage. In absolute liberation from the female stereotype she rejects the proposal of Mr. Darcy (likely the richest man she is ever to meet) as well revealing a complete disregard for societal norms and her prescribed role as a woman. In conclusion, Elizabeth Bennets character intrigues many, unique individualism plainly setting her far from the stereotype of her gender. Throughout Pride and Prejudice, several references enlighten every fine attribute of Elizabeths remarkable character. Her interactions throughout the novel quite clearly depict her as an extremely atypical female when juxtaposed against the norm of her gender, during the distinctive period of Regency England in the year 1813. Through her independence and defiance, clearly outspoken nature, and inimitable ideals concerning matrimony, Elizabeths character undeniably challenges the stipulated roles and formal protocol of the women in her time period. She remains principled and unshaken by the overwhelmingly strict expectations of society. Her every action becomes governed by assurance of her happiness alone, while decisions  too depend exclusively on her own sense of correct choices. The character of Elizabeth Bennet provides inspiration for many modern women to develop a sense of courage and confidence, demonstrated by her determined will to speak her mind in effort to support certain unique principles of marriage. Elizabeth figuratively compares with Frodo Baggins of Lord of the Rings, by being dragged into a quest in which a ring is central. In marrying Darcy, she overturns the social hierarchy by taking a husband who remains considerably superior in social class. Using her newly enhanced opinions to understand what constitutes a happy (as well as proper) marriage on her independent terms she makes certain of her true happiness, concluding in final contentment that she will now never desire to discard her ring into Mount Doom. â€Æ'Works Cited Austen, Jane. Pride and Prejudice. Ann Arbor: Borders Classics, 2006.

Possente Spirto

Possente Spirto : Opinions in the style of Monteverdi and Artusi Sabrina K. Robbins Musicology 210 Dr. Rachel Golden October 23, 2012 Music has always and will always remain a subject of debate on some level. Throughout the years music has developed, progressed, and changed alongside mankind.There were numerous arguments as to what was considered proper and what the rules should be regarding composition during the development of music in each era. With the emergence of the Baroque era of music, the stylistic elements of homophony, alongside features such as basso continuo and a more common use of dissonance, became the norm. Prior to this development music was more structured, following contrapuntal styles and sticking to a strict tonal center.The stretch of time between the Renaissance and Baroque periods of music offered a unique perspective of the changing opinions through the treatises critiquing the current music. A famous argument of this kind took place between Giovanni Artu si and Claudio Monteverdi regarding the latter’s madrigal Cruda Amarilli. It is through the study of this treatise that it is possible to ascertain what the composers’ opinions may have been on other pieces of music through applying their criteria to analyzing other songs.Possente Spirto by Monteverdi is a piece to which these elements can be applied and a logical assumption of the feelings of both of these composers can be reached. Artusi, a composer and music critic, was deeply rooted in the theoretical concepts of the Renaissance era of music, and outwardly condemned the emergence of the new styles in the Baroque era. He was quite conservative, and passionately felt that Monteverdi’s music was distasteful and disrespectful in that it broke the previously established composition rules purely for the pleasure of stepping over boundaries.Possente Spirto blatantly disregards numerous key elements in Renaissance music by incorporating a heavily ornamented, single recitative voice, accompanied only by melodic harmony that is unobtrusive. Artusi was far more concerned with a vertical harmony than linear, horizontal harmony. The vocal portion of this piece is obviously the focal point but according to the ideals that Artusi held, the virtuosic monodic singing was not what would have been desired. Counterpoint and a strict tonal center were the elements that were pleasing to the ear of music enthusiasts and musicians.The dissonances used at unexpected times, the blatant disregard for previously set composition rules, and implementation of features such as modal mixture would make the music inaccessible and disrespectful to listeners who were expecting certain key harmonic elements from their musical experience. While Artusi would not have directly named Monteverdi in a criticism of Possente Spirto(just as he did not name him in his critique of Cruda Amarilli), it would have been evident to any reader that his intent was to examine the validity o f his compositional works.Despite Artusi’s distaste for Monteverdi’s works, his criticisms were less about the composer himself and more in regards to the developing and changing style of modern music. The â€Å"incorrect† voice leading and use of dissonance in an uncharacteristic way was not only outside of what was considered acceptable in composition but was something that was difficult to adjust to hearing. The sound of the linear harmony and dissonance was radically different from anything that had been heard previously, and new inventions are not always attractive at first.On the other side of the argument, Monteverdi was ahead of the time and was experiencing relatively smooth sailing through the awkward transitional period between the Renaissance and Baroque musical eras. He was principally concerned with the listener connecting emotionally and mentally with the music and text of his pieces, so he incorporated a great deal of text painting into his music . He began to focus heavily on the relationships of the text and music in his compositions.He thought that the listeners of his music should understand the messages of the songs, and began to find ways to utilize creative methods of description and expression in his compositions. Monteverdi was essentially ushering in a new age of music by pushing boundaries with his usage of consonances and dissonances. He was unafraid of breaking rules, and did so by throwing the ideas of counterpoint, chiefly the resolutions of notes and atypical harmonic structure, out the proverbial window.In Possente Spirto many fresh, new ideas are starting to arise. It is clearly evident through the utilization of ideas behind the text, the vocal articulation, and also the lyre-like sound of the accompaniment that Monteverdi was heavily influenced by ancient Greek music. Monteverdi would have justified his usage of dissonance by attributing it to the idea of conveying a mood to the listener. The old rules of the First Practice (counterpoint, traditional harmonic resolution, vertical harmony, etc) were of less concern to Monteverdi.The mixture of dramatic musical elements with the text for effect was the ultimate goal in his compositions, and he would have given little thought to the opinions of Artusi on the subject matter. His ideas of the Second Practice helped bridge the gap from Renaissance into the Baroque. In Possente Spirto, the text is what takes center stage in the song. Without the virtuosic singing and delicate musical harmony propelling the feelings of sadness and longing forward in the aria, the song would not have had the overall mood that Monteverdi was looking for.This piece is intended to make the listener connect with Orpheus and sympathize with his plight. The implementation of previously unused harmonic elements made the connection with the singer possible, and that in turn created the blending of music and drama that Monteverdi sought out in this work. Both of the points made by Artusi and Monteverdi were valid and well thought out. The argument simply boiled down to the fact that Artusi was more heavily rooted in tradition than Monteverdi, and favored the traditional voice leading and counterpoint practices.He did not want to see rules broken purely for the sake of breaking them. On the other hand, Monteverdi was more of a dreamer and chose to focus on the emotional element of the music. He wanted to have the listener connect to the music in a way that would make the feel the emotions in the text through the song. Neither composer had any concrete evidence to support the â€Å"winning facts† of the debate. It should be kept in mind that it is likely that Artusi was not exactly attacking Monteverdi, but rather arguing the practices coming into light in composition. It was rumored that they even became friends later.The only question on the table is whether it is better to stay with tradition, or take chances and break out of what is co nsidered acceptable and normal. Monteverdi did just that, and received a great deal of criticism for his work while simultaneously creating pieces that are considered to be great works of art. Possente Spirto, while lovely and evocative, incorporated many of the same elements that caused Artusi’s original critique. At what point does breaking rules becoming less about creating something new and evocative and more about simply ruffling feathers? That, I think, is a subject that will remain up for debate.

Postive Psychology Essay Example | Topics and Well Written Essays - 750 words

Postive Psychology - Essay Example "Community Alliance for Responsibility, Empowerment and Safety" program was developed. This program involves one employee to oversee low-level adult offenders who perform court-ordered community service. This program has cut over 50-weeded lots; filled hundreds of 30-gallon size trash bags with garbage taken from gutters and ditches; and decreased graffiti off of numerous sites of private and public property. Hiring a new Executive Director is one that will have great effect on the society. Developing a program that would benefit the citizens of Houston is very essential. This program aims to establish a strong reputation for its ability to identify and seize opportunities to help solve tough problems. Applying Positive Psychology principles on the proposed programs will make people positive and productive individuals. ... PROGRAM COMPONENTS for FOUR SUBDIVISIONS INCLUDE: Spiritual motivation. "Let us hear the conclusion of the whole matter: Fear God, and keep his commandments: for this is the whole duty of man (Ecclesiastes 12:13)." Individual and group counseling, family counseling, relapse prevention, aftercare counseling, parenting education, life skills training. Case management and other legal matters Nutritional education HIV/AIDS education, testing and support Mental health counseling (as appropriate) Job preparation training and assistance Recreational activities Housing referrals Academic enhancement, including tutoring. Skill development Curriculum based support groups Educational presentations and literacy development Enrichment including computer training, soccer team and other sports team, cheerleaders, dance, arts and music programs. Community involvement, including presentations by community leaders and sports figures as well as volunteer activities and Children's services CONCLUSION Applying Positive Psychology principles on the proposed programs will make people positive and productive individuals. The first component included in the program is "Spiritual Motivation," and one of the principles of Positive Psychology is that "Only intrinsic religiosity is associated with positive mental health." So as the Executive Director, I will make sure that each individual will know the real meaning of spirituality and its major impact in the lives of people in the society. Life begins when you know the meaning of life. People struggle to find the essence of life and spiritual motivation is one of the answers to that. Learned individuals flourish not only in knowledge and

Software Architectures Essay Example | Topics and Well Written Essays - 1000 words - 1

Software Architectures - Essay Example The main content areas of an information system are data, process, infrastructure and organization. System design involves reviewing each of the content areas in order to solve the client’s problems when it becomes operational. Infrastructure defines the hardware and software components as essential to facilitate performing the activities of the system i.e. data storage and servers. System design involves modification of an organization in order to match the functioning of the system. It includes identifying persons who update, create or delete data. The data in the CDM are converted to data design. The process of system designing involves specifying the detailed system logic. This consists of elements such as the computers for database management systems, servers, telecommunications, and programming languages. Customer’s procedure, standards and policy manuals may bring constraints to the system design.11 The infrastructure design should specify the development environment. Critical issues under infrastructure include the following. †¢Language(s) of the system. This concern specifying what language and design approach will be is used to develop the system. Include versions, i.e. The system is a Client/Server system. The client wants Visual Basic language. The system will be installed in the computer using a run-time version †¢ Host environment. Specify what machines will be used. Include how the machines will fit into the infrastructure, i.e. the system will be installed in the MIS Division, which that are attached to the College of Computer LAN. These machines have a processor, 64MB of RAM and 500MB of disk storage. †¢ Network. For systems operating over a network it is always vital to specify network requirements. The issue is not in changing the network, but the impact of the new system. Large systems require new links and components. The design specifies the client, server, LAN and

Pluto Essay Example | Topics and Well Written Essays - 750 words

Pluto - Essay Example Pluto has five moons which are Charon, Hydra, Nix, Kerberos, and Styx and there are believed to be many other smaller moons some which have been discovered and others which have not yet been discovered. Charon which is the largest was also discovered first in 1978 followed by Hydra and Nix which were both discovered in 2005. The discovery of these moons suggests that the planet may be having a ring system though past studies show that no ring exists on the planet or on its periphery. It is also worth noting that these moons are unusually close to the dwarf planet than all other objects that surround it and also then it is the case in the majority of other planets which have been explored. The origin and the identity of Pluto are not very clear and there are actually many differing theories all of which try to explain these two aspects. Some of these theories suggest that the planet used to be a moon of the neighboring planet Neptune that escaped from the normal path of circulation he nce resulting to a new planet. Other theories differ with this and argue that the paths of the two planets are far away from each and thus there is no possibility of the two colliding. There is a lot to be explored on Pluto and therefore the possibility of a spacecraft landing on the planet this year is expected to be of great benefit as far as studies concerning the planet are concerned. There is, therefore, need for more studies and visits to be launched in order to solve all the mysteries surrounding the planet.

Energy resources and their impact on economy Essay

Energy resources and their impact on economy - Essay Example The reason behind this is that the utilization of these forms of energy is heavily technologically dependent and these technologies are still in the stages of infancy. There are many difficulties in implementing these technologies, some of them being their higher costs and sophistication of usage procedures to the common layman. Coal is a fossil fuel that is formed in the earth's crust from slow metamorphosis of organic matter under high temperature and pressure conditions. The rate at which coal is formed is very slow and it takes millions of years for the formation of coal. Coal originally formed from ancient plants that after death were decomposed and somehow buried under layers of sedimentary rocks. With the passage of time more and more layers of sediments formed on this decomposed plant matter. This exerted high pressure and resulted in increase of temperature. Over millions of years these physical conditions caused coal to form from the elements carbon, hydrogen, oxygen, nitrogen, sulphur, and mineral compounds that were present in the plant matter. Coal formation began during the carboniferous period known as the first coal age which spanned 360 to 290 million years before the present day. Coal deposits are fo... There exists a hairline difference between the terms "reserves" and "resources". Reserves are coal deposits that be extracted profitably with the application of technology where as resources are an estimate of the world's total coal deposits. All the resources may not be reserves because some of them are not commercially accessible. Total recoverable reserves of coal around the world are estimated at 1,001 billion tons-enough to last approximately 190 years at current consumption levels. Historically, estimates of world recoverable coal reserves, although relatively stable, have declined gradually from 1,167 billion tons at the beginning of 1990 to 1,083 billion tons in 2000 and 1,001 billion tons in 2003. The most recent assessment of world coal reserves includes a substantial downward adjustment for Germany, from 73 billion tons of recoverable coal reserves to 7 billion tons. (International Energy Outlook 2005) The coal reserves are geographically distributed as follows: Europe, in cluding all of Russia and other countries that made up Soviet Union, 44 percent; North America, 28 percent; Asia, 17 percent; Australia, 5 percent; Africa, 5 percent; and South America, 1 percent. (Speight 2003) A substantial quantity of coal consumed is burned in electric power stations to produce electricity. When coal is burned energy is obtained in the form of heat. In a power station that uses coal as the fuel, this heat converts water into super heated steam at high pressure which is made to rotate a turbine connected to a dynamo to produce electricity. The steel industry uses coke. Coke is a hard substance consisting of nearly pure carbon and is obtained by heating coal in absence of air. The coke is combined with iron

Introduction to Combustion and Fire Case Study Example | Topics and Well Written Essays - 4250 words

Introduction to Combustion and Fire - Case Study Example For example, when chlorofluorocarbons (CFCs) are exposed to high energy sun rays, chlorine and bromine atoms are released. These chlorine/bromine atoms act as catalysts in the breaking up of ozone molecules. Free radicals are atoms or molecules possessing one or more unpaired electrons. Free radicals are formed as intermediaries of reactions. One of the most common free radicals is the hydroxyl free radical (HO∙). Ions, free atoms, and free radicals are reaction intermediaries. While ions are charged species, free radicals are groups containing unpaired electrons, and free atoms are single atoms without charge. Ions can exist in a stable equilibrium, but free atoms and free radicals are highly unstable and react with other atoms or molecules soon after formation. During bond formation, an electron from 2s orbital is moved to 2pz orbital. This process requires a small amount of energy as the energy gap between 2s and 2p orbitals are less. So the new electronic structure is 1s22s12px12py12pz1 Pentane has a molar mass of 72.15 gmol-1. For 1 mole of pentane, mass is 72.15 g. As calculates earlier, at temperature 298.15K and pressure 1.013Ãâ€"105 Pa, the volume of 1 mol of pentane is 2.447Ãâ€"10-2 m3. A reaction where the products are in the most stable state is known as a complete chemical reaction. In the fire, a complete chemical reaction with no fuel and oxygen left is known as a stoichiometric reaction. The reaction mixtures in such a state are stoichiometric mixtures. The stoichiometric oxygen to fuel mass ratio r is determined from the equation. The equivalence ratio () which describes the state of the reactant mixture, is defined as (Quintere, 2006): Concentration is a measure of the packaging of particles per unit volume and its unit is moles per dm3 or moldm-3. A mole is a unit to measure the amount of substance. One mole of a substance contains 6.023Ãâ€"1023 atoms, molecules, or ions.   

Films and the American History Essay Example | Topics and Well Written Essays - 250 words

Films and the American History - Essay Example From this paper it is clear that the United States of America under the presidency of George Bush had a major role in the Gulf War. In the movie, we see that Major Archie Gates and Chief Elgin cannot believe what the inhabitants go, though. They find out that the government incited the citizens to fight the rule of Saddam Hussein with a promise to support them. They later find out that the government did not give them the support they promised. The United States government is highly involved in the business in the Middle East. The new evidence of nonsupport from the government makes them think deeply about their role in the fight.As the discussion stresses the movie shows the weakness of the American president because the directors show the affair between Bill and Monica. The relationship is a depiction of real life events that occur in the real-time events. Historically, the United States and Britain fought each other during the American Revolution. On the other hand, during the Wor ld War, the nations were strong allies and the United States protects Britain. In addition to the World War, the two nations were strong allies during the Cold War and Gulf War. There are moments historically when the only superpower country to give United States support in the Iraq war was Britain.  The relationship the two countries are strong, and both leaders work towards a general goal. The wives of both leaders also have a strong relationship showing that there is a special kind of relationship.

Spiderman Analysis-Engish Essay Example | Topics and Well Written Essays - 1000 words

Spiderman Analysis-Engish - Essay Example Like most lonely, somewhat nerdy fellows, Peter is in love with a beautiful, popular young woman, who just happens to be his next door neighbor, Mary Jane. Peter does not have parents; he lives with his Aunt and Uncle, a slightly older couple. Peter is used to being ignored, and even pushed around. He has very little self-esteem and would prefer to take photographs of other people living life, then live life himself. And yet, by fate, he is bitten by the â€Å"super spider† and inherits the amazing abilities that the spider possesses. The change from Peter Parker having the powers of Spiderman and Peter Parker becoming Spiderman was evident. While Peter Parker was enjoying his new abilities (climbing walls, being able to suspend mild flight, spin webs, perfect vision and hearing, amazing reaction time), he doesn’t automatically come to the assumption that he should use his powers to protect the innocent. He, like most people in his position would do, first thought of ho w this new gift would most benefit him. While investigating that possibility, he made a decision that cost him the life of his Uncle Ben. After accepting the pain of the loss, Peter realized that there was a huge amount of injustice in the world and that there was no one fighting for the people, no one to scare those that would do others harm. That gave way to the birth of Spiderman and all of the â€Å"great responsibility† that comes along with being a superhero. Spiderman, despite his best efforts, begins his superhero career with a very skeptical crowd. Most of the miraculous things that he does are misinterpreted and even presented to be a problem that was caused by him, so that he could fix it and be a hero. In the beginning, Spiderman is saving the lives of the faceless, no one that Peter Parker would have any personal connection to. However, when the faceless become Peter Parker’s loved ones, the issue of keeping the superhero and the regular

Consequences Of An Older Population Research Paper

Consequences Of An Older Population - Research Paper Example Consequences of an Older Population Diverse studies have been undertaken to closely monitor factors that influence living conditions of a population. With vast developments that have been achieved over the past centuries, medical breakthroughs and improved nutrition, concurrent with other innovative products and services have resulted in an increasing percentage of aging population worldwide. The study conducted by the collaborative agencies on aging under the U.S. Department of Health and Human Services revealed that most significant increases in the number of people aged 65 and above were identified in developing nations where the percentage increase is projected to reach 140% by the year 2030 (US DHHS, n.d, 2). It has been the natural desire of humans to live a productive and rewarding life for a long time. However, despite the obvious benefits of a long life, there are consequences that should be evaluated in the light of its impact from various perspectives. In this regard, the current study aims to would proffer pertinent issues on the consequences of an older population. ... Medicaid, Medicare, Disability, Welfare and Supplemental Security Income, and The Older Americans Act). Options that could be helpful in relieving this potential burden, in terms of increased taxes, Social Security reform, and reduction in assistance would also be discussed. Finally, from the information gathered from scholarly sources, the paper would propose viable and validated measures to address the significant onus of an aging population. Causes of an Increasing Aging Population The study conducted by Schrier (n.d.) identified a significant cause for the aging population being â€Å"the long-term historical decline in the fertility of the population. In other words, the falling birth rate is responsible for fewer children in the population, and this, in turn, means that the older age groups will form a larger share† (Schrier, n.d, 3). This was supported by the discourse entitled Demographics of an Aging Population provided a clear explanation for the rationale for popula tion age structures in both mortality and fertility transformations, known as demographic transitions (Demographics, n.d). It was reported that the decline in rates of mortality were contributed by improved medical breakthroughs, immunizations, personal hygiene and public focus on health and cleanliness of the environment, that enabled people to survive from various diseases. On the other hand, fertility rates declined due to an interplay of economic and social factors. The need to generate more income for the family led to women joining the work force thereby leaving lesser time for child bearing and rearing, especially in developed countries. Trends in Global Aging The US DHHS (n.d.) have revealed trends in global aging, to wit: (1) â€Å"the overall

“Inevitable vs. Amendable” Essay Example for Free

â€Å"Inevitable vs. Amendable† Essay The film â€Å"Inequality for All† tries to explain; what is the current status of the distribution of wealth and that of income equality? Why this is happening and if this is a problem. Yes, as stated in the film, social inequality is inevitable. But, there is without a doubt a problem with United States distribution of wealth. One of the facts that really opened my eyes was the fact that the 400 richest Americans, together hold more wealth than the poorest 150 million Americans have together. This said, it is scary to think about how obscure was the knowledge we had on the one percent with given how much economic influence they have. The minimum wages vs. growth of productivity graph is one that I found very interesting. Why is â€Å"just† in today’s society to be part a more productive workforce that gets paid less than the workforce we had a few decades ago? The line graph for productivity growth is rising every year, meaning that more work is being done. On the other hand, the minimum wages growth rates were rising but after a while they seem to have plateau and they have been like this for about 30 years. Advances in globalization and technology are also inevitable because it is simple economics that a product shall be produced in the cheapest way possible. Yes, technology does create jobs but as we see in the film companies like Amazon are also opting to operate with high tech machinery instead of the traditional assembly line. Women going to work, general workforce working for longer hours and borrowing money from the financial sectors are coping mechanisms that the middle class used to keep up with their good lifestyles, but in my opinion these are more like defense mechanisms in order to survive in the concrete jungle with the same wages they had 30 years ago. One other comparison that I liked was how the widening inequality leads to a deficiency cycle and when the wealth is equally distributed economic stability is transfused from sector to sector creating a domino effect leading to a virtuous cycle.

Alternatives To The Instrument Landing Systems Engineering Essay

Alternatives To The Instrument Landing Systems Engineering Essay Pilots have been faced with horrors of not being able to safely carry out the whole flight envelope activities during unfavourable weather conditions. The solution was the idea of somehow aiding pilots with instruments that would help get the job done. The Instrument Landing System (ILS), being the first, did break the ice but its faults and restrictions paved way for alternatives like the MPL, JPAL, IGS and TLS amongst others. It cannot be overlooked though that the ILS is still the most common of all approaches and pilots are tested numerous times on the workings of the ILS during their flight career. The Instrument Landing System (ILS) is an instrument presented, pilot interpreted, precision approach aid. The system provides the pilot with instrument indications which, when utilised in conjunction with the normal flight instruments, enables the aircraft to be manoeuvred along a precise, predetermined, final approach path. [1] Tests of the ILS began in 1929 and the Civil Aviation Authority (CAA) authorised installation of the system in 1941 at six locations. The first landing of a scheduled U.S. passenger airliner using ILS was on January 26, 1938, as a Pennsylvania Central Airlines Boeing 247-D flew from Washington D.C. to Pittsburgh and landed in a snowstorm using only the Instrument Landing System.[2] The first fully automatic landing using ILS occurred at Bedford Airport UK in March 1964. [3] 1.1 Overview on the Instrument Landing System (ILS) The ILS uses two primary signals: a localizer for lateral guidance (VHF) operating between frequencies 108.10MHz and 111.95MHz; and a glide slope for vertical guidance (UHF) operating between 329.30MHz to 335.00MHz. The localizer provides course guidance throughout the descent path to the runway threshold from a distance of 18 NM from the antenna between an altitude of 1,000 feet about the highest terrain along the course line and 4,500 feet about the elevation of the antenna site. [4] On the other hand, the glide consists of two overlapping beam modulated at 150Hz and 90Hz. The centre line of the glideslope signal is arranged to define a glide slope of approximately 3Â ° above ground level with the beam being 0.7Â ° below the glideslope centreline and 0.7Â ° above the glideslope centreline i.e. 1.4Â ° in total. The transmitter is located 750 to 1,250 ft. down the runway from the threshold, offset 400 to 600 ft. from the runway centreline [5]. 1.2 Limitations facing the ILS The complexity of the ILS localizer and glide-slope system gives rise to its high installation cost. Also, there are topographic limitations with the ILS because of the complex siting requirements due to the sensitivity of both the localizer and glide slope systems. The localizers full functionality is limited due to effects from obstructions in the signal broadcast areas like hangers and large buildings and the glide-slope conversely is affected by the terrain in front of the glide-slope antenna. If terrain is sloping or uneven, reflections can create an uneven glide-path causing unwanted needle deflections. Additionally, the ILS only supports straight-in approaches since its signals are pointed in one direction by the positioning of the antennae arrays. Furthermore, the ILS suffers from frequency congestion because of a finite number of available frequencies (only 40 channels in all)[6], and has frequency modulation interference problems in some areas.[7] Also, the fact that it is not easily deployable makes it fall out of favour with the military. These main facts resulted into the development of the Microwave Landing System (MLS) with one intention only, to replace the ILS. 2. The Microwave Landing System (MLS) 2.1 History of the MLS The Microwave Landing System was designed to replace or supplement the ILS. Tests of the MLS began in 1972 in Australia. Most of this work was jointly done by the then Federal Department of Civil Aviation (DCA), and the Radio Physics Division of the Commonwealth Scientific and Industrial Research Organisation (CSIRO). The project was called Interscan which was one of the many Microwave Landing System under consideration internationally. Interscan was chosen by the FAA in 1975 and ICAO in 1978 as the format to be adopted. [8] The MLS was standardised in 1988 and approved for use in international civil aviation. [9] 2.2 Overview and advantages of the MLS over the ILS MLS employs 5GHz transmitters at the landing place which use passive electronically scanned arrays to send scanning beams towards approaching aircraft. An aircraft that enters the scanned volume uses a special receiver that calculates its position by measuring the arrival times of the beams. The MLS operates in the microwave spectrum of 5.0-5.25 GHz/15.4-15.7 GHz. It provides azimuth, elevation and distance measurement to aircraft having the necessary components installed. It has various advantages over the ILS as it is more accurate and preferable in providing approach guidance to aircrafts. It is capable of providing fan coverage range of +/- 40 degrees either side of the antennae and a horizontal distance of about 20NM from the runway touchdown point for azimuth approaches and +/- 20degrees fan coverage area from a horizontal distance of 5NM for back azimuth for a missed approach situation. The ILS on the other hand can only accurately provide course guidance of +/- 10 degrees eit her side of the antennae from a horizontal distance of 18NM for forward azimuth approach and a further +/- 25 degrees fan coverage area (+/- 35degrees in total for azimuth approaches) from a horizontal distance of 10NM for back azimuth on a missed approach. Any area beneath the +/- 35 degrees coverage area, signal may provide incorrect or undesirable readings by the instruments. [10] This statement is graphically represented in figure 1. Figure 1. The MLS coverage area. Also, the DME (Distance Measuring Equipment) on the ILS provides a range accuracy of +/- 1,200ft. as compared with greatly improved version on the MLS called the DME/P (for Precision) which provides a range accuracy of +/- 100feet making it possible for the MLS to guide the extremely accurate CATIII approaches which was previously normally carried out with expensive ground based high precision radar equipment with the ILS. Furthermore, with the MLS having 200 channels for communication/broadcast operating between 5031 and 5090.6 MHz (far from FM broadcast frequencies) gives it further advantage through getting rid of jamming and interference problems faced with the ILS because its operational channel frequencies are fairly close to FM broadcast frequencies. In addition, the MLS antennae are small because it transmits at higher frequencies, cheaper and easy to construct and maintain as it does not employ a Localizer and glideslope transmitter. It can also be placed anywhere as compared to the ILS system that has to be placed at the end of the runway and along the approach path. Again, it has the advantage of providing precision guidance to V/STOL (Shot Take-off and Landing) aircrafts and helicopters in small areas e.g. roof-top helicopters which is impossible with the ILS. In addition, it cannot only accommodate straight-in or segmented approaches but also curved approaches as the transmitter does not have to be in direct alignment with the receiver before landing can be possible and this is so because the MLS transmitter signal covers a very large fan-shaped coverage area. Finally, because of the higher frequency the MLS operate, precisely in a ratio of 50:1 as compared with the ILS, it therefore requires a smaller antenna. A 1o beam-width antenna for a MLS requires 12ft (3.6m) antenna while a typical ILS system would require a 600ft (180m) antennae size for the same 1o beam-width losing out again to the MLS to size advantage. [11]. The MLS expectation to replace the ILS was actually the reverse as a lot of airliners were reluctant to converting to MLS because it required them installing and or changing some equipment on board the aircraft and on the ground. Also, at almost about the same time came the invention of the GPS. The GPS required no installations in airports. It never employed placing any antennae along the runway like the ILS and MLS. This eliminates the siting requirements imposed by both initial systems and gave rise to simplicity. 3. The GPS and the WAAS: The GPS, Global Positioning System, consists of a space-based radio navigation satellite and network of ground stations for controlling and monitoring. The space portion consists of at least 24 GPS satellites orbiting the earth twice in a day at a speed of about 7,000miles per hour and about 11,000 miles in altitude from the earths surface.[12] The GPS provides accurate data of current position. Basically, to get current location using the GPS, data is sent from the object e.g. the aircraft and it measures the time taken for the wave to reach the satellite and return and by means of triangulation using at least three satellites, accurate location can be calculated. The GPS though also has some limitations. It cannot be employed for precision landing since it does not give enough vertical accuracy and as known, vertical accuracy ensures safer landing. The GPS precisely provides a vertical accuracy of about 15meters and even the certification for the least, CAT I landing requires a ver tical accuracy of at least 4meters. The inaccuracy is caused by the interaction of the radio signals with large waves in the ionosphere. This interaction slows down the time for the radio signal to be reflected back to its source since even a very small clock error multiplied by the very large speed of light (the speed at which satellite signals propagate) results in a large positional error. These errors aroused the introduction of the WAAS (Wide Area Augmentation System). The WAAS basically employs the same space-based satellite and ground based stations as the GPS but its main difference is that it sends out correctional signal to augment errors in the GPS signal. Two master stations located on either coast collects data from the reference station and a GPS correction message. This correction accounts for GPS satellite orbit and clock drift plus signal delays caused by the atmosphere and ionosphere. The corrected differential message is then broadcast through one of two geostatio nary satellites (satellites with a fixed position over the equator). The information is compatible with the basic GPS signal structure, which means any WAAS-enabled GPS receiver can read the signal. For some users, in the U.S for example, they are not able to receive the corrected WAAS signal because of obstructions from trees and mountains. So plainly speaking, the GPS or WAAS is just not accurate enough to replace the ILS and this further encouraged the manufacture of other precision landing systems. [13] 4. JPALS (Joint Precision Approach and Landing System) JPALS or the Joint Precision Approach Landing System is an all weather precision landing system developed and mainly intended for use by the military. The crash of a U.S. military transport in Bosnia in 1996, while flying a non-precision approach in adverse weather highlighted the need for a near-term, rapidly deployable precision approach system. As a result, the Air Mobility Command is pursuing an initiative to field a precision approach system to solve problems like the one encountered in Bosnia. In 1992, the Assistant Secretary of Defense for C3I directed a study to analyze existing emerging PALS technologies. Tasking was passed through the Air Force to the DoD Policy Board on Federal Aviation, which chartered the Precision Landing Study Advisory Group (PLSAG) to produce a JPALS Mission Needs Statement (MNS). The Joint Requirements Oversight Council validated the MNS in August 1995. [14] JPALS was developed by the military for two main reasons: 1. They needed an all weather precision landing system that is highly mobile and open to most if not all military scenarios, such as landing on ships, rough terrains etc. and 2. They needed a rugged system that would work and withstand any weather and environmental conditions. JPALS is similar in concept to the civilian Local Augmentation Area System, LAAS. JPALS augments GPS to provide precision approach and landing information for military aircrafts flying in poor weather or low visibility. A typical JPALS system consists of both ground and airborne component. The ground component transmits correctional messages to augment the GPS signal. It also transmits a set of co-ordinate data defining the final approach path. The airborne receiver on the aircraft determines the position relative to the desired approach path or runway if you like. This information is displayed on the pilots PFD. A single JPALS ground system can support multiple runways in an airport and it can also support different approach path to a single runway. Also, the same JPALS ground system can support approaches to nearby airports within a 10-20miles radius. Furthermore, if a portion of the runway sustains damage, the landing threshold position can be moved further up front the runway. JPALS is divided into two main categories namely the SRGPS and the LDGPS. SRGPS provides highly accurate precision landing for aircrafts aboard ships, S/VTOL, helicopters. LDGPS is further subdivided into three categories. The fixed base used by military for on going operations around the world, the Tactical base designed for short-term critical operations and the Special missions is highly portable and used by Special Forces on special missions. Figure 2 simplifies the subdivisions. Figure 2. JPALS classifications A typical Special Missions JPALS system would be carried in two bag packs and can be set up by two airmen within a few minutes. The prototype system consists of a two GPS receiver enclosure, a laptop and a data link transmitter. In November 2007, this system was set up and tested at the FAAs Williams J. Hughes technical centre in Atlantic City, NJ. This man-packed system was tested using the FAAs covey test aircraft and by a C21 aircraft provided by the airforces Flight Standard Agency. These two aircrafts successfully demonstrated the ability of the man-packed JPALS system to support the CAT1 approach and also further demonstrated its success after the landing threshold position was moved further up the runway in a case of a damaged portion of the runway. [15][16] 5. Conclusion: The ability for aircraft to fly and land under any circumstance is very much important as it ensures safety, integrity to the industry and comfort to passengers. As pilots of the earlier days were almost completely paralysed due to effects from bad weather or worse would crash as it happened to the military transport aircraft in Bosnia urged the need for solutions. The faults in the ILS paved way for the MLS, GPS, JPALS and others. A Transponder Landing System or the TLS would also work where a typical ILS would not provided there is no paralysis in funds. The latest alternative to the ILS is the Localise Performance with Vertical guidance or the LPV which is also based on the same operation as the WAAS and as of Nov. 2008[update], the FAA has published more LPV approaches than Category I ILS procedures. Generally, these precision and landing systems have greatly improved the integrity and safety of the Aviation industry, both military and civilian.

Flow Cytometry for the Evaluation of Semen

Flow Cytometry for the Evaluation of Semen State of the Art in Sperm Assessment Using Flow Cytometry Abstract Flow cytometry is emerging as a substantial tool in the domain of modern andrology for the routine analysis of spermatozoa. Recent application of flow cytometry in the artificial insemination industry especially for pig is a new approach. Until very recent, analysis of semen samples was routinely performed by microscopical evaluation and manual techniques by laboratory operators; analysis is inclined due to comprehensive variability among observers, influencing its clinical validity. During last decade, to evaluate farm animal semen, variety of new flow cytometric techniques have been intercalated which made possible a wide spread evaluation of several sperm functionality and characteristics. Here in this paper, an initiative has been taken to explore numerous current flow cytometry developments pressing for andrological tests. After the invention of flow cytometry, sperm evaluation by traditional (microscopic) means became questioned and avoided due to the robust advantages of flow cytometry over the microscopic methods. By the recent development of diverse fluroscence probes, flow cytometry became capable of analyzing number of sperm characteristics like viability, capacitation, acrosomal integrity, membrane permeability, membrane integrity, mitochondrial status, DNA integrity, decondensation of DNA and differences between gametes based on sex. The application of flow cytometry to their detection allows increased numbers of spermatozoa to be assessed over a short time-period, provides the opportunity of working with small sample sizes, increases the repeatability of data obtained, removes the subjectivity of evaluation and allows simultaneous assessment of multiple fluorochromes. Thus, flow cytometry is a technique capable of generating significantly novel data and allows the design and execution of exper iments that are not yet possible with any other technique. Nowadays, semen evaluation using laboratory analyses is very meaningful to the artificial insemination industry to provide the most desired quality product to customers. Future development of flow cytometric techniques will permit further advances both in our knowledge and in the improvement of assisted reproduction techniques. In this paper, the main semen attributes that can be analyzed with fluorochromes and adapted for use with a flow cytometer will be reviewed and the relationship of these tests to fertility will be discussed. Introduction Up to now, semen evaluation is considered as the most important laboratory test that has enabled us to identify and predict clear-cut cases of fertility (Jarow et al., 2002), infertility or even of potential sub-fertility (Rodrà ­guez-Martà ­nez, 2007). Determination of the potential fertility of semen sample and, in the long run, of the male from which it has been collected is the ultimate goal of semen evaluations in clinically healthy sires. Now a days, many methods for the estimate the possible fertilizing capacity of a semen sample and, or in the word, of the male (reviewed by Dziuk 1996; Rodrà ­guez-Martà ­nez et al. 1997a; Rodrà ­guez-Martà ­nez and Larsson 1998; Saacke et al. 1998; Larsson and Rodrà ­guez-Martà ­nez 2000; Rodrà ­guez- Martà ­nez 2000, 2003; Popwell and Flowers 2004; Graham and Mocà © 2005; Gillan et al. 2005) are existing. The methods routinely accustomed for evaluation of the quality of a semen sample involved an evaluation of general appearance, volume, pH, sperm concentration, viability, morphology and motility. Most of these evaluations are based on microscopic analyses that only measure relatively a few numbers of spermatozoa within a population. In most of the cases, these are time-consuming; results obtained are controversial and are not translatable. It should also be noted that such conventional techniques are apt to extreme inter-ejaculate variation, even when the laboratory methodology has been standardized. In the wake of this information, new opportunities have arisen for the development of methods for the diagnosis of male infertility, many of which have been shown to exhibit a prognostic value that eludes conventional semen profiling. Moreover, ejaculated spermatozoa are nowadays handled for use in assisted reproductive technologies, such as the artificial insemination of chilled, frozen-thawed or sexed semen, and IVF. During this long processes, number of steps like semen extension, fluorophore loading, ultrav iolet and laser illumination, high-speed sorting, cooling and cryopreservation are followed, which create a scope to impose different degrees of change in sperm functionality followed by suffer of damage to sperm membranes, organelles or the DNA content. Therefore, although several assays have been developed to monitor these sperm parameters, recently it is being claimed by many groups that buck of those so-called procedures are incomplete, time consuming and laborious. Flow cytometry in diverse technical applications proposes many advantages for the analysis of sperm quality. Flow cytometry is a method where multiple fluorescences and light scattering can be induced allowing single cell or particles illumination in suspension while they flow very rapidly through a sensing area. The increasing use over the past decade of flow cytometry in the leading laboratories in human and veterinary andrology has dramatically increased our knowledge of sperm function under physiological and biotechnological conditions. Flow cytometers is capable to acquire data from several subpopulations within a sample in a few minutes, making it perfect for assessing heterogenous populations in a semen sample. Flow cytometry was initially developed in the 1960s, after that flow cytometry is performing automated separation of cells based on the unique recognition of cellular patterns in a population feasible (Hulett et al., 1969). Likewise, cellular patterns can be recognized by utilizing such a separation approach, in each cells within a population (Baumgarth and Roederer, 2000; Herzenberg et al., 2006). The first notion of flow cytometry development was for medical and clinical applications such as haematology and oncology. Although still much research is going on these medical areas and account for the vast majority of publications on this robust technique, but during the past few years it is being used in a diverse areas, such as bioprocess monitoring, pharmacology, toxicology, environmental sciences, bacteriology and virology. Together with elevated use in many areas, recent advancement of flow cytometry increased its application in the reproductive biology especially for andrology. Although flow cytometry may overestimate the population of unlabelled cells (Petrunkina and Harrison, 2009), plethora of research from our group in pig (Pena et al., 2003, 2004, 2005; Spjuth et al., 2007; Fernando et al., 2003; Saravia et al.,2005, 2007,2009; De Ambrogi et al., 2006; ) bull (Bergquist et al., 2007; Nagy et al., 2004; Januskauskas et al., 2003; Bergqvist et al., 2007; Hallap et al., 20 05, 2006;) stallion ( Kavak et al., 2003; Morrell et al., 2008) indicate that newly developed fluorescent stains and techniques of flow cytometry has made possible a more widespread analysis of semen quality at a biochemical, ultrastructural and functional level. Therefore, flow cytometry is the current technical solution for rapid, precisely reproducible assessment of sperm suspensions. In this review we have described potentiality and scope of flow cytometry for the evaluation of semen, and the way in which this technique can be used in clinical applications for andrology based on some of our previous experiences. Definition of flow cytometry The definition of a flow cytometer is ‘an instrument which measures the properties of cells in a flowing stream or ‘an instrument that can measure physical, as well as multi-colour fluorescence properties of cells flowing in a stream. In other word, cytometry is a method which measure physical and chemical attributes of cells or other particles. Such a measurement is made when cells or other particles pass in single file through some sort of measuring apparatus in a stream of fluid. The data obtained can be used to understand and monitor biological processes and develop new methods and strategies for cell detection and quantification. Compared to other traditional analytical tools, where a single value for each attribute is obtained for the whole population, flow cytometry provides data for each and every particle detected. As cells differ in their metabolic or physiological states, flow cytometry allows us not only to detect a particular cell type but also to find different subpopulations according to their structural or physiological parameters. Flow cytometry is a technique for measuring components (cells) and the properties of individual cells in liquid suspension. In essence, suspended cells are brought to a detector, one by one, by means of a flow channel. Fluidic devices under laminar flow define the trajectories and velocities that cells traverse across the detector, and fluorescence, absorbance, and light scattering are among the cell properties that can be detected. Flow sorting allows individual cells to be sorted on the basis of their measured properties, and one to three or more global properties of the cell can be measured. Flow cytometers and cell sorters make use of one or more excitation sources and one or two fluorescent dyes to measure and characterize several thousands of cells per second. Flow cytometry presents objective and precise results (Bunthof et al., 2001; Shleeva et al., 2002), which help to overcome the problems with the manual methods described above. Function and types of flow cytometry A flow cytometer is made of three main systems, fluidics, optics and electronics. ItI It can acquire data on all subpopulations within a sample, making it ideal for assessment of heterogenous population, such as spermatozoa. The adaptation of flow cytometry to sperm assessment came in to function when it was used for measuring their DNA content (Evenson et al., 1980) and its application for analyzing semen has been increased rapidly in last decade. Flow cytometry is now applied for the evaluation semen such as sperm viability, acrosomal integrity, mitochondrial function, capacitation status, membrane fluidity, DNA status and so on. Continuous innovation of new fluorescent stains and techniques facilitated the flow cytometric evaluation of spermatozoa. Flow cytometry allows the observation of physical characteristics, such as cell size, shape and internal complexity, and any component or function of the spermatozoon that can be detected by a fluorochrome or fluorescently labeled compound. The analysis is objective, has a high level of experimental repeatability and has the advantage of being able to work with small sample sizes. Flow cytometry also has the capacity to detect labeling by multiple fluorochromes associated with individual spermatozoa, meaning that more than one sperm attribute can be assessed simultaneously. This feature has an added benefit for semen analysis, as few single sperm parameters show significant correlation with fertility in vivo for semen within the acceptable range of normality (Larsson and Rodriguez-Martinez, 2000) and it is the general statistics that the more sperm parameters can be tested, the more accurate the fertility prediction becomes (Amman and Hammerstedt, 1993). There are two main types of flow cytometers-analysers and sorters are in use. Together with data collection on cells, sorters have the potentiality to sort cells with particular properties (defined by the flow cytometer operator) to extremely high purities. There are also a number of commercial flow cytometers that have been developed for particular analytical requirements. Partec manufacture a Ploidy Analyser and also a Cell Counter Analyser. Optoflow has developed a flow cytometer for the rapid detection, characterization and enumeration of microorganisms. Luminex is developing technology for multiplexed analyte quantitation using a combination of microspheres, flow cytometry and high speed digital processing. Advantages of FC compared to other conventional techniques to explore sperm structure and function Use of authentic assays in the fertility clinic and artificial insemination industries increasing day by day. In this respect, use of flow cytometry might be an important attempt to resolve sustaining problem with so called commonly used manual method for the semen analysis. An additional source of laboratory variation is the low number of sperms analyzed with such techniques. It is worth mentinign here that so called method deal only with few hundred sperm. When we deal with such a few sperm population, there is a possibility that obtained result might not be statistically significant (Russel and Curtis, 1993). The methods which are frequently used are enable to determine sperm concentration (Jorgensen et al., 1997), motility or morphology only (Keel et al., 2002). Objectivity, cell number measured, speed of count and precision are the advantages of flow cytometry to conventional light microscopy techniques (Spano and Evenson, 1993). The technique now a days has been used to determi ne a number of factors including those of acrosome status, membrane integrity, mitochondrial function as well as multiparameter measurement in human (Garrido et al., 2002). Flow cytometry has the ability to analyze thousands of cells in few minutes. In our series of studies, we demonstrated the feasibility and reproducibility of an automated method to evaluate sperm cell type, count, and viability in human boar samples. In our hand, the precision of the flow cytometric analysis is satisfactory in a diverse species (boar, bull, stallion etc), and the observed errors were significantly better than those obtained from the so-called manual methods. Although there are diverse benefits of flow cytometer for the analysis of semen, feasibility of applying flow cytometry sometimes restricted to researcher due to the high outlay and difficulties of operation associated with the requirement of a skilled operator. Further, a flow cytometer is very large and cannot resist shocks associated with movement, and it also requires much space in the laboratory. Whatever may be the limitation, the development of more affordable ‘‘bench-top flow cytometers in recent time raised the potential essentialities to semen analysis. If the further application of flow cytometric analysis is considered further, it might be seen that it is growing popularities as a technique for assessing more than one sperm attribute, simultaneously. Compared to traditional microscopic techniques, flow cytometry analysis is allowing to give a far more simplified and objective method of semen analysis, especially in relation to fertilization with acrosome reactivity potential of spermatozoa (Uhler et al., 1993; Purvis et al., 1990; Carver-Ward et al., 1996). A large number of different techniques to estimate sperm concentration have been reported. In the mid-1990s a series of fixed-depth disposable slides were evaluated as rapid and effective pieces of equipment for the estimate of sperm concentration. Data from a number of preliminary studies proposed that, at least in the 20-mm-depth format, such chambers resulted in a noticeable underestimate of sperm concentration compared to the gold standard (improved Neubauer hemocytometer). According to the World Health Organization that ‘‘such chambers, whilst convenient in that they can be used without dilution of the specimen, might lead to inaccuracy (World Health Organization, 1999). Data from Tomlinson and colleagues indicate that two proprietary disposable slides (Microcell, Conception Technologies, San Diego, Calif; Leja, Leja Products, BV Nieuw- Vennep, The Netherlands) can result in a lower concentrations of sperm compared to the hemocytometer method (Tomlinson et al., 2001) . In contrast, plenty of reports document unacceptable differences between different laboratories and even between different individuals, although fewer studies attempt to address these issues. So, what is wrong? Improvement of semen quality testing has been emphasizing in some reports (Jorgensen et al., 1997; Keel et al., 2000). But due to low number of sperm evaluation by the conventional method results in poor reproducibility. These problems might be overcome when using flow cytometry. The validation of method is a challenge due to its essentiality of having specific, precise, objective, and accurate evaluation to establish a correlation of fertility data or to predict potential of a semen sample accurately (Amann, 1989). In a fertility clinic, precision of data in important as the result of semen analysis is frequently used to manage fertility of a patient and treatment of the unfertile couples. Thus, it is important to take into consideration within and between laboratory variations for successful infertility treatments. Sometimes its a matter of argument that compared to flow cytometry, fluorescent microscopy evaluate â€Å"patterns of fluorescence rather than the fluorescence intensity. Flow cytometer has the lack of ability to discriminate sperm containing a fluorescent marker bound to the equatorial segment or over one of the acrosomal membranes (Parinaud et al., 1993; Mortimer and Camenzind, 1989; Mortimer et al., 1987). Tao et al. (1993) compared flow cytometry and epifluorescent microscopy with various lectins and indicated that there is almost no difference between methodologies for detection of the acrosome reaction. However, it has been argued that lectins do not bind specifically to the acrosomal region of the sperm (Purvis et al., 1990; Holden and Trounson, 1991) and that other binding sites can be easily distinguished by epifluorescence microscopy, whereas flow cytometry identifies the signal from the entire sperm. Additionally, conventional light microscopic semen assessment is increasingly being replaced by fluorescent staining techniques, computer-assisted sperm analysis (CASA) systems, and flow cytometry (PenËÅ"a et al., 2001; Verstegen et al., 2002). Additional advantages over existing techniques are that this approach is faster than the hemacytometer and that cellular debris, fat droplets, and other particulate material in extended semen are not erroneously counted as sperm, as often occurs with electronic cell counters. This method can also be used to determine the number of somatic cells in a semen sample. Application of flow cytometry for sperm count Sperm count is an important predominant factor for the evaluation of sperm fertility potential. Accurate determination of sperm cell concentration is critical especially in AI industry because it provides assurance to customers that straws of extended semen contain the sperm numbers indicated which will help to decide appropriate doze especially for pig. Accuracy of sperm count is a common problem in the andrological laboratories and accurate measure of sperm concentration is particularly important for export in which verification of numbers may be required. Routine sperm counts can help to identify possible processing errors within a specific batch of semen or on a particular day, should those errors occur. As sperm counting procedures become more refined, routine counting can be used to monitor subtle changes in daily semen processing that might affect the number of sperm packaged in a straw. Every time new and more accurate methods for the sperm count determinations are coming and being replaced by the older ones. Some laboratories are trying the Maklerm counting chamber (Se if- Medical, Haifa, Israel) and other improved hemacytometers, such as the MicroCellTM (Fertility Technologies, Inc., Natick, MA); however, these techniques will likely have standard lems similar to those associated with the standard hemacytometers. Although hemacytometers are routinely used for sperm counts, due to the slow process and need for multiple measurements of each sample, the chance of error increase. Freund and Carol (ref) stated that a difference of 20% were not unusual between the determinations by the same technician. Electronic counters provide much more rapid counting, are easier to use, and give more repeatable results among technicians. However, those instruments tend to include in the sperm count any somatic cells present, immature sperm forms, cytoplasmic droplets, debris, and bacteria, thereby inflating the concentration value (Ref). Spectrophotometer is recently being used in the AI industries to assess sperm concentration by determining turbidity of a semen s ample using an instrument previously calibrated for sperm concentration with a hemacytometer or Coulter counter (Ref). The accuracy of this method depends on the methods used for spectrophotometer calibration. Although, sperm concentration can also be determined by spectrophotometrically, the debris present in the raw semen crease problem with misestimation. Sperm number in the frozen thawed semen is difficult to ascertain as most of the extender contain egg yolk particles, fats and other particles which affect measurement of sperm with electric cell counter or spectrophotometers (Evenson et al., 1993). On the other hand flow cytometry created possibilities of a rapid determination of sperm number in a precise form. It is the flow cytometry which can reduce intra-laboratory and inter-laboratory variation and conflict regarding sperm concentration assessment. Computer assisted semen analyzer is robust technique for analyzing sperm movement which can count sperm as well; but such an a nalyzer most of the cases use some counting chamber or hemacytometer which itself can generate error. Although, hemacytometer was originally developed for blood cell counting, its use is now diverse including andrological laboratories for sperm counting. Around two-decade ago flow cytometry was suggested for sperm numbers in straws of cryopreserved bull semen. Christensen et al. (-) observed similar results for sperm count with flow cytometry and hemocytometer for a number of species. Now a day a simultaneous determination of sperm viability and sperm concentration is possible which can avoid the chance of occurring differences between ejaculates leading lack of coordination with field fertility and laboratory analyses. Thus the present technology is more precise which can get rid of variation from handling the sperm sample and variation from pipetting and the analysis itself. Further, Prathalingam et al. (2006) concluded that there is similarities for sperm count result between flow cytometry and two newly approached method (image analysis and fluorescent plate reader) for sperm counting. Though, use of fluorescent plate was emphasized due to low cost and allowing large number of cells counting from a large number of ejaculates. Although flow cytometry has become a valuable instrument for andrological determinations, it is also blamed that sperm concentration by flow cytometry signify a higher value than the real one. The possibility arise might be due to that semen samples often contain some alien materials such as immature germ cells, epithelial cells, blood cells, cytoplasmic droplet, cellular debris etc. In the same way, frozen semen has higher chance to introduce such material as they contain diluents components especially egg yolk particles. These particles and cell debris might have frontal and side light scatter parameters those are similar to spermatozoa. Such sperm-count-overestimation problem arisen in our cases also, especially when we deal with frozen semen. Further it is also claimed that flow cytometry has a tendency to overestimate viable spermatozoa. We are also experienced with such trouble which we guess might be due to that egg particles of extender are considered as viable cell as for it s staining pattern. Our yet to publish data indicate that this problem can be mimic by a centrifugation process and by using low concentration sample for evaluation with flow cytometry. Very recently Petrunkina and Harrison (2009) proposed a mathematical equation for fixing this flow cytometric sperm counting. Thus much research is going on and we hope such discrepancy will completely be resolved near future to get advantage from this robust technology for sperm counting. Flow cytometry for detecting sperm intactness -Viability of spermatozoa The viability of spermatozoa is a key determinant of sperm quality and prerequisite for successful fertilization. Viability of spermatozoa can be assessed by numerous methods, but many are slow and poorly repeatable and subjectively assess only 100 to 200 spermatozoa per ejaculate. Merkies et al. (2000) compared different methods of viability evaluation. They concluded that Eosin-nigrosin overestimate viability while fluorescent microscope and flow cytometry estimate similar trend of viability. Current flow cytometric procedures are able to simultaneously evaluate sperm cell viability together with some other attributes. This method has been successfully used for assessing spermatozoa viability in men (Garner and Johnson, 1995), bulls (Garner et al., 1994; Thomas et al., 1998), boars (Rodrà ­guez-Martà ­nez, 2007; Garner and Johnson, 1995; Garner et al., 1996), rams (Garner and Johnson, 1995), rabbits (Garner and Johnson, 1995), mice (Garner and Johnson, 1995; Songsasen et al., 199 7), poultry and wildfowl (Donoghue et al., 1995; Blanco et al., 2000) and honey bees (Collins and Donoghue, 1999; Collins, 2000) and in fish (Martin Flajshans et al., 2004). Considerable information has accumulated on the use of fluorescent staining protocols for assessing sperm viability (Evenson et al., 1982). The SYBR 14 staining of nucleic acids, especially in the sperm head, was very bright in living sperm. Good agreement was observed between the fluorescent staining method and the standard eosin-nigrosine viability test; the flow cytometric method showed a precision level higher than that of the manual method. One of the first attempts to assess sperm viability utilized rhodamine 123 for determining potentiality of mitochondrial membrane while ethidium bromide for membrane integrity through flow cytometry (Garner et al., 1986). Other combinations that have been used to examine the functional capacity of sperm are carboxyfluorescein diacetate (CFDA) and propidium iodide (PI) (Garner et al., 1988; Watson et al., 1992); carboxydimethylfluorescein diacetate (CMFDA), R123, and PI (Ericsson et al., 1993; Thomas and Garner, 1994); and PI, pisum sativum agglutinin (PSA), and R123 (Graham et al., 1990). The most generally used sperm viability stain combinations is SYBR-14 and PI at present. This stains are now sold commercially as live/dead viability kit. When these two stains are combinely used, the nuclei of viable sperm take fluoresce green and membrane integrity lost cells take red stain. This staining technique has been used in a number of species, including the boar (Garner and Johnson, 1995; Saravia et al.,2005, 2007,2009). Although species differences do exist in the function of spermatozoa, the Live/Dead stain may similarly have no adverse affect on fertilization in the equine, although it remains to be tested in this species. Recently a new instrument (Nucelocounter-SP100) has been introduced to evaluate sperm concentration [11] and viability. Due to the small size and low cost, this instrument has been attracted for field measurements of both concentration and viability. In our hand this instrument was also became useful for the quick measurement of sperm concentration an d viability in stallion (Morrell et al., 2010). Fluorescent probes such as H33258, requiring flow cytometric analysis with a laser that operates in the ultraviolet light range, are less commonly used as this is not a standard feature on the smaller analytical machines. However, one alternative is to use a fluorometer. A fluorometer is a relatively low-cost piece of portable equipment that permits a rapid analysis to be carried out on a sample. Januskauskas et al. (2001) used H33258 to detect nonviable bull spermatozoa by fluorometry and obtained an inverse correlation between the damaged cells per cent and the field fertility. Another option is fluorescent attachments for computer-assisted semen analysis devices. For example, the IDENT fluorescence feature of the Hamilton-Thorne IVOS permits staining with H33258 allowing an assessment of sperm viability to be made along with motility. Fluorochromes used to assess sperm viability by both approach could be utilized in combination with each other. In that case, when CFDA is used combined with PI, three populations of cells as live, which are green; dead, which are red; and a third population which is stained with both and represents dying spermatozoa can be identified. This combination was found useful by Almlid and Johnson (1988) for frozen-thawed boar spermatozoa for monitoring membrane damage at the time of evaluation of various freezing protocols. Further, Harrison and Vickers (1990) also noticed that this combination with a fluorescent microscope is effective indicator of viability of fresh, incubated or cold-shocked spermatozoa in boar and ram. Contrasting to these, Garner et al. (1986) was failed to find a relationship between bull sperm viability and fertility when using combination of CFDA/PI . Flow cytometry for evaluating sperm viability appears to be a precious tool in the AI industry. When a high number of sperm is packed in each insemination dose, the effect of selecting the best ejaculates according to sperm viability has a relatively limited effect. However, sperm viability might be more important when combined with low-dose inseminations. The FACSCount AF flow cytometer also determines sperm concentration accurately and precisely during the same analysis (Christensen et al., 2004a). The combined assessment of sperm viability and concentration appears to be useful in the wake of improving quality control at AI stations. Because of the results of this trial, this method has been implemented by Danish AI stations (Christensen et al., 2005). Relatively bright fluorescence was found also in the mitochondrial sheath of living sperm. But the mechanism and mode of action by which SYBR-14 binds to the DNA of sperm is not known. It is know that PI stains nucleic acids by inte rcalating between the base pairs (Krishan, 1975). Viability stains can also be used in conjugation with fluorescently labeled plant lectins for simultaneous assessment of the plasma membrane integrity and the acrosome integrity (Nagy et al., 2003). It is conceivable that assessment of viability using SYBR-14 dye does not damage spermatozoa, since Garner et al. (5) found that insemination of boar sperm stained with SYBR-14 did not compromise fertilization or even the development of flushed porcine embryos in vitro. Non-viable sperms can be detected using the membrane-impermeable nucleic acid stains which positively identify dead spermatozoa by penetrating cells with damaged membranes. Plasma membrane which is intact will not permit these stains entering into the spermatozoa and staining the nucleus. Most frequently used stains include phenanthridines, for example propidium iodide (PI; (Matyus, 1984) ethidium homodimer-1 (EthD-1; (Althouse et al., 1995), the cyanine Yo-Pro (Kavak, 2003) and the bizbenzimidazole Hoechst 33258 (Gundersen and Shapiro, 1984). After a series of comparison between fertility of cryopreserved stallion spermatozoa with a number of laboratory assessments of semen quality as assessed by flow cytometry using PI, Wilhelm et al. (1996) concluded that viability is the single laboratory assay that correlated with fertility. -Sperm plasma membrane integrity Although the sperm plasma membrane covers the entire cell, it consists of three distinct membrane compartments, one which covers the outer acrosomal membrane, one which covers the post acrosomal portion of the sperm head, and one which covers the middle and principal pieces. Sperm membrane is directly or ind Flow Cytometry for the Evaluation of Semen Flow Cytometry for the Evaluation of Semen State of the Art in Sperm Assessment Using Flow Cytometry Abstract Flow cytometry is emerging as a substantial tool in the domain of modern andrology for the routine analysis of spermatozoa. Recent application of flow cytometry in the artificial insemination industry especially for pig is a new approach. Until very recent, analysis of semen samples was routinely performed by microscopical evaluation and manual techniques by laboratory operators; analysis is inclined due to comprehensive variability among observers, influencing its clinical validity. During last decade, to evaluate farm animal semen, variety of new flow cytometric techniques have been intercalated which made possible a wide spread evaluation of several sperm functionality and characteristics. Here in this paper, an initiative has been taken to explore numerous current flow cytometry developments pressing for andrological tests. After the invention of flow cytometry, sperm evaluation by traditional (microscopic) means became questioned and avoided due to the robust advantages of flow cytometry over the microscopic methods. By the recent development of diverse fluroscence probes, flow cytometry became capable of analyzing number of sperm characteristics like viability, capacitation, acrosomal integrity, membrane permeability, membrane integrity, mitochondrial status, DNA integrity, decondensation of DNA and differences between gametes based on sex. The application of flow cytometry to their detection allows increased numbers of spermatozoa to be assessed over a short time-period, provides the opportunity of working with small sample sizes, increases the repeatability of data obtained, removes the subjectivity of evaluation and allows simultaneous assessment of multiple fluorochromes. Thus, flow cytometry is a technique capable of generating significantly novel data and allows the design and execution of exper iments that are not yet possible with any other technique. Nowadays, semen evaluation using laboratory analyses is very meaningful to the artificial insemination industry to provide the most desired quality product to customers. Future development of flow cytometric techniques will permit further advances both in our knowledge and in the improvement of assisted reproduction techniques. In this paper, the main semen attributes that can be analyzed with fluorochromes and adapted for use with a flow cytometer will be reviewed and the relationship of these tests to fertility will be discussed. Introduction Up to now, semen evaluation is considered as the most important laboratory test that has enabled us to identify and predict clear-cut cases of fertility (Jarow et al., 2002), infertility or even of potential sub-fertility (Rodrà ­guez-Martà ­nez, 2007). Determination of the potential fertility of semen sample and, in the long run, of the male from which it has been collected is the ultimate goal of semen evaluations in clinically healthy sires. Now a days, many methods for the estimate the possible fertilizing capacity of a semen sample and, or in the word, of the male (reviewed by Dziuk 1996; Rodrà ­guez-Martà ­nez et al. 1997a; Rodrà ­guez-Martà ­nez and Larsson 1998; Saacke et al. 1998; Larsson and Rodrà ­guez-Martà ­nez 2000; Rodrà ­guez- Martà ­nez 2000, 2003; Popwell and Flowers 2004; Graham and Mocà © 2005; Gillan et al. 2005) are existing. The methods routinely accustomed for evaluation of the quality of a semen sample involved an evaluation of general appearance, volume, pH, sperm concentration, viability, morphology and motility. Most of these evaluations are based on microscopic analyses that only measure relatively a few numbers of spermatozoa within a population. In most of the cases, these are time-consuming; results obtained are controversial and are not translatable. It should also be noted that such conventional techniques are apt to extreme inter-ejaculate variation, even when the laboratory methodology has been standardized. In the wake of this information, new opportunities have arisen for the development of methods for the diagnosis of male infertility, many of which have been shown to exhibit a prognostic value that eludes conventional semen profiling. Moreover, ejaculated spermatozoa are nowadays handled for use in assisted reproductive technologies, such as the artificial insemination of chilled, frozen-thawed or sexed semen, and IVF. During this long processes, number of steps like semen extension, fluorophore loading, ultrav iolet and laser illumination, high-speed sorting, cooling and cryopreservation are followed, which create a scope to impose different degrees of change in sperm functionality followed by suffer of damage to sperm membranes, organelles or the DNA content. Therefore, although several assays have been developed to monitor these sperm parameters, recently it is being claimed by many groups that buck of those so-called procedures are incomplete, time consuming and laborious. Flow cytometry in diverse technical applications proposes many advantages for the analysis of sperm quality. Flow cytometry is a method where multiple fluorescences and light scattering can be induced allowing single cell or particles illumination in suspension while they flow very rapidly through a sensing area. The increasing use over the past decade of flow cytometry in the leading laboratories in human and veterinary andrology has dramatically increased our knowledge of sperm function under physiological and biotechnological conditions. Flow cytometers is capable to acquire data from several subpopulations within a sample in a few minutes, making it perfect for assessing heterogenous populations in a semen sample. Flow cytometry was initially developed in the 1960s, after that flow cytometry is performing automated separation of cells based on the unique recognition of cellular patterns in a population feasible (Hulett et al., 1969). Likewise, cellular patterns can be recognized by utilizing such a separation approach, in each cells within a population (Baumgarth and Roederer, 2000; Herzenberg et al., 2006). The first notion of flow cytometry development was for medical and clinical applications such as haematology and oncology. Although still much research is going on these medical areas and account for the vast majority of publications on this robust technique, but during the past few years it is being used in a diverse areas, such as bioprocess monitoring, pharmacology, toxicology, environmental sciences, bacteriology and virology. Together with elevated use in many areas, recent advancement of flow cytometry increased its application in the reproductive biology especially for andrology. Although flow cytometry may overestimate the population of unlabelled cells (Petrunkina and Harrison, 2009), plethora of research from our group in pig (Pena et al., 2003, 2004, 2005; Spjuth et al., 2007; Fernando et al., 2003; Saravia et al.,2005, 2007,2009; De Ambrogi et al., 2006; ) bull (Bergquist et al., 2007; Nagy et al., 2004; Januskauskas et al., 2003; Bergqvist et al., 2007; Hallap et al., 20 05, 2006;) stallion ( Kavak et al., 2003; Morrell et al., 2008) indicate that newly developed fluorescent stains and techniques of flow cytometry has made possible a more widespread analysis of semen quality at a biochemical, ultrastructural and functional level. Therefore, flow cytometry is the current technical solution for rapid, precisely reproducible assessment of sperm suspensions. In this review we have described potentiality and scope of flow cytometry for the evaluation of semen, and the way in which this technique can be used in clinical applications for andrology based on some of our previous experiences. Definition of flow cytometry The definition of a flow cytometer is ‘an instrument which measures the properties of cells in a flowing stream or ‘an instrument that can measure physical, as well as multi-colour fluorescence properties of cells flowing in a stream. In other word, cytometry is a method which measure physical and chemical attributes of cells or other particles. Such a measurement is made when cells or other particles pass in single file through some sort of measuring apparatus in a stream of fluid. The data obtained can be used to understand and monitor biological processes and develop new methods and strategies for cell detection and quantification. Compared to other traditional analytical tools, where a single value for each attribute is obtained for the whole population, flow cytometry provides data for each and every particle detected. As cells differ in their metabolic or physiological states, flow cytometry allows us not only to detect a particular cell type but also to find different subpopulations according to their structural or physiological parameters. Flow cytometry is a technique for measuring components (cells) and the properties of individual cells in liquid suspension. In essence, suspended cells are brought to a detector, one by one, by means of a flow channel. Fluidic devices under laminar flow define the trajectories and velocities that cells traverse across the detector, and fluorescence, absorbance, and light scattering are among the cell properties that can be detected. Flow sorting allows individual cells to be sorted on the basis of their measured properties, and one to three or more global properties of the cell can be measured. Flow cytometers and cell sorters make use of one or more excitation sources and one or two fluorescent dyes to measure and characterize several thousands of cells per second. Flow cytometry presents objective and precise results (Bunthof et al., 2001; Shleeva et al., 2002), which help to overcome the problems with the manual methods described above. Function and types of flow cytometry A flow cytometer is made of three main systems, fluidics, optics and electronics. ItI It can acquire data on all subpopulations within a sample, making it ideal for assessment of heterogenous population, such as spermatozoa. The adaptation of flow cytometry to sperm assessment came in to function when it was used for measuring their DNA content (Evenson et al., 1980) and its application for analyzing semen has been increased rapidly in last decade. Flow cytometry is now applied for the evaluation semen such as sperm viability, acrosomal integrity, mitochondrial function, capacitation status, membrane fluidity, DNA status and so on. Continuous innovation of new fluorescent stains and techniques facilitated the flow cytometric evaluation of spermatozoa. Flow cytometry allows the observation of physical characteristics, such as cell size, shape and internal complexity, and any component or function of the spermatozoon that can be detected by a fluorochrome or fluorescently labeled compound. The analysis is objective, has a high level of experimental repeatability and has the advantage of being able to work with small sample sizes. Flow cytometry also has the capacity to detect labeling by multiple fluorochromes associated with individual spermatozoa, meaning that more than one sperm attribute can be assessed simultaneously. This feature has an added benefit for semen analysis, as few single sperm parameters show significant correlation with fertility in vivo for semen within the acceptable range of normality (Larsson and Rodriguez-Martinez, 2000) and it is the general statistics that the more sperm parameters can be tested, the more accurate the fertility prediction becomes (Amman and Hammerstedt, 1993). There are two main types of flow cytometers-analysers and sorters are in use. Together with data collection on cells, sorters have the potentiality to sort cells with particular properties (defined by the flow cytometer operator) to extremely high purities. There are also a number of commercial flow cytometers that have been developed for particular analytical requirements. Partec manufacture a Ploidy Analyser and also a Cell Counter Analyser. Optoflow has developed a flow cytometer for the rapid detection, characterization and enumeration of microorganisms. Luminex is developing technology for multiplexed analyte quantitation using a combination of microspheres, flow cytometry and high speed digital processing. Advantages of FC compared to other conventional techniques to explore sperm structure and function Use of authentic assays in the fertility clinic and artificial insemination industries increasing day by day. In this respect, use of flow cytometry might be an important attempt to resolve sustaining problem with so called commonly used manual method for the semen analysis. An additional source of laboratory variation is the low number of sperms analyzed with such techniques. It is worth mentinign here that so called method deal only with few hundred sperm. When we deal with such a few sperm population, there is a possibility that obtained result might not be statistically significant (Russel and Curtis, 1993). The methods which are frequently used are enable to determine sperm concentration (Jorgensen et al., 1997), motility or morphology only (Keel et al., 2002). Objectivity, cell number measured, speed of count and precision are the advantages of flow cytometry to conventional light microscopy techniques (Spano and Evenson, 1993). The technique now a days has been used to determi ne a number of factors including those of acrosome status, membrane integrity, mitochondrial function as well as multiparameter measurement in human (Garrido et al., 2002). Flow cytometry has the ability to analyze thousands of cells in few minutes. In our series of studies, we demonstrated the feasibility and reproducibility of an automated method to evaluate sperm cell type, count, and viability in human boar samples. In our hand, the precision of the flow cytometric analysis is satisfactory in a diverse species (boar, bull, stallion etc), and the observed errors were significantly better than those obtained from the so-called manual methods. Although there are diverse benefits of flow cytometer for the analysis of semen, feasibility of applying flow cytometry sometimes restricted to researcher due to the high outlay and difficulties of operation associated with the requirement of a skilled operator. Further, a flow cytometer is very large and cannot resist shocks associated with movement, and it also requires much space in the laboratory. Whatever may be the limitation, the development of more affordable ‘‘bench-top flow cytometers in recent time raised the potential essentialities to semen analysis. If the further application of flow cytometric analysis is considered further, it might be seen that it is growing popularities as a technique for assessing more than one sperm attribute, simultaneously. Compared to traditional microscopic techniques, flow cytometry analysis is allowing to give a far more simplified and objective method of semen analysis, especially in relation to fertilization with acrosome reactivity potential of spermatozoa (Uhler et al., 1993; Purvis et al., 1990; Carver-Ward et al., 1996). A large number of different techniques to estimate sperm concentration have been reported. In the mid-1990s a series of fixed-depth disposable slides were evaluated as rapid and effective pieces of equipment for the estimate of sperm concentration. Data from a number of preliminary studies proposed that, at least in the 20-mm-depth format, such chambers resulted in a noticeable underestimate of sperm concentration compared to the gold standard (improved Neubauer hemocytometer). According to the World Health Organization that ‘‘such chambers, whilst convenient in that they can be used without dilution of the specimen, might lead to inaccuracy (World Health Organization, 1999). Data from Tomlinson and colleagues indicate that two proprietary disposable slides (Microcell, Conception Technologies, San Diego, Calif; Leja, Leja Products, BV Nieuw- Vennep, The Netherlands) can result in a lower concentrations of sperm compared to the hemocytometer method (Tomlinson et al., 2001) . In contrast, plenty of reports document unacceptable differences between different laboratories and even between different individuals, although fewer studies attempt to address these issues. So, what is wrong? Improvement of semen quality testing has been emphasizing in some reports (Jorgensen et al., 1997; Keel et al., 2000). But due to low number of sperm evaluation by the conventional method results in poor reproducibility. These problems might be overcome when using flow cytometry. The validation of method is a challenge due to its essentiality of having specific, precise, objective, and accurate evaluation to establish a correlation of fertility data or to predict potential of a semen sample accurately (Amann, 1989). In a fertility clinic, precision of data in important as the result of semen analysis is frequently used to manage fertility of a patient and treatment of the unfertile couples. Thus, it is important to take into consideration within and between laboratory variations for successful infertility treatments. Sometimes its a matter of argument that compared to flow cytometry, fluorescent microscopy evaluate â€Å"patterns of fluorescence rather than the fluorescence intensity. Flow cytometer has the lack of ability to discriminate sperm containing a fluorescent marker bound to the equatorial segment or over one of the acrosomal membranes (Parinaud et al., 1993; Mortimer and Camenzind, 1989; Mortimer et al., 1987). Tao et al. (1993) compared flow cytometry and epifluorescent microscopy with various lectins and indicated that there is almost no difference between methodologies for detection of the acrosome reaction. However, it has been argued that lectins do not bind specifically to the acrosomal region of the sperm (Purvis et al., 1990; Holden and Trounson, 1991) and that other binding sites can be easily distinguished by epifluorescence microscopy, whereas flow cytometry identifies the signal from the entire sperm. Additionally, conventional light microscopic semen assessment is increasingly being replaced by fluorescent staining techniques, computer-assisted sperm analysis (CASA) systems, and flow cytometry (PenËÅ"a et al., 2001; Verstegen et al., 2002). Additional advantages over existing techniques are that this approach is faster than the hemacytometer and that cellular debris, fat droplets, and other particulate material in extended semen are not erroneously counted as sperm, as often occurs with electronic cell counters. This method can also be used to determine the number of somatic cells in a semen sample. Application of flow cytometry for sperm count Sperm count is an important predominant factor for the evaluation of sperm fertility potential. Accurate determination of sperm cell concentration is critical especially in AI industry because it provides assurance to customers that straws of extended semen contain the sperm numbers indicated which will help to decide appropriate doze especially for pig. Accuracy of sperm count is a common problem in the andrological laboratories and accurate measure of sperm concentration is particularly important for export in which verification of numbers may be required. Routine sperm counts can help to identify possible processing errors within a specific batch of semen or on a particular day, should those errors occur. As sperm counting procedures become more refined, routine counting can be used to monitor subtle changes in daily semen processing that might affect the number of sperm packaged in a straw. Every time new and more accurate methods for the sperm count determinations are coming and being replaced by the older ones. Some laboratories are trying the Maklerm counting chamber (Se if- Medical, Haifa, Israel) and other improved hemacytometers, such as the MicroCellTM (Fertility Technologies, Inc., Natick, MA); however, these techniques will likely have standard lems similar to those associated with the standard hemacytometers. Although hemacytometers are routinely used for sperm counts, due to the slow process and need for multiple measurements of each sample, the chance of error increase. Freund and Carol (ref) stated that a difference of 20% were not unusual between the determinations by the same technician. Electronic counters provide much more rapid counting, are easier to use, and give more repeatable results among technicians. However, those instruments tend to include in the sperm count any somatic cells present, immature sperm forms, cytoplasmic droplets, debris, and bacteria, thereby inflating the concentration value (Ref). Spectrophotometer is recently being used in the AI industries to assess sperm concentration by determining turbidity of a semen s ample using an instrument previously calibrated for sperm concentration with a hemacytometer or Coulter counter (Ref). The accuracy of this method depends on the methods used for spectrophotometer calibration. Although, sperm concentration can also be determined by spectrophotometrically, the debris present in the raw semen crease problem with misestimation. Sperm number in the frozen thawed semen is difficult to ascertain as most of the extender contain egg yolk particles, fats and other particles which affect measurement of sperm with electric cell counter or spectrophotometers (Evenson et al., 1993). On the other hand flow cytometry created possibilities of a rapid determination of sperm number in a precise form. It is the flow cytometry which can reduce intra-laboratory and inter-laboratory variation and conflict regarding sperm concentration assessment. Computer assisted semen analyzer is robust technique for analyzing sperm movement which can count sperm as well; but such an a nalyzer most of the cases use some counting chamber or hemacytometer which itself can generate error. Although, hemacytometer was originally developed for blood cell counting, its use is now diverse including andrological laboratories for sperm counting. Around two-decade ago flow cytometry was suggested for sperm numbers in straws of cryopreserved bull semen. Christensen et al. (-) observed similar results for sperm count with flow cytometry and hemocytometer for a number of species. Now a day a simultaneous determination of sperm viability and sperm concentration is possible which can avoid the chance of occurring differences between ejaculates leading lack of coordination with field fertility and laboratory analyses. Thus the present technology is more precise which can get rid of variation from handling the sperm sample and variation from pipetting and the analysis itself. Further, Prathalingam et al. (2006) concluded that there is similarities for sperm count result between flow cytometry and two newly approached method (image analysis and fluorescent plate reader) for sperm counting. Though, use of fluorescent plate was emphasized due to low cost and allowing large number of cells counting from a large number of ejaculates. Although flow cytometry has become a valuable instrument for andrological determinations, it is also blamed that sperm concentration by flow cytometry signify a higher value than the real one. The possibility arise might be due to that semen samples often contain some alien materials such as immature germ cells, epithelial cells, blood cells, cytoplasmic droplet, cellular debris etc. In the same way, frozen semen has higher chance to introduce such material as they contain diluents components especially egg yolk particles. These particles and cell debris might have frontal and side light scatter parameters those are similar to spermatozoa. Such sperm-count-overestimation problem arisen in our cases also, especially when we deal with frozen semen. Further it is also claimed that flow cytometry has a tendency to overestimate viable spermatozoa. We are also experienced with such trouble which we guess might be due to that egg particles of extender are considered as viable cell as for it s staining pattern. Our yet to publish data indicate that this problem can be mimic by a centrifugation process and by using low concentration sample for evaluation with flow cytometry. Very recently Petrunkina and Harrison (2009) proposed a mathematical equation for fixing this flow cytometric sperm counting. Thus much research is going on and we hope such discrepancy will completely be resolved near future to get advantage from this robust technology for sperm counting. Flow cytometry for detecting sperm intactness -Viability of spermatozoa The viability of spermatozoa is a key determinant of sperm quality and prerequisite for successful fertilization. Viability of spermatozoa can be assessed by numerous methods, but many are slow and poorly repeatable and subjectively assess only 100 to 200 spermatozoa per ejaculate. Merkies et al. (2000) compared different methods of viability evaluation. They concluded that Eosin-nigrosin overestimate viability while fluorescent microscope and flow cytometry estimate similar trend of viability. Current flow cytometric procedures are able to simultaneously evaluate sperm cell viability together with some other attributes. This method has been successfully used for assessing spermatozoa viability in men (Garner and Johnson, 1995), bulls (Garner et al., 1994; Thomas et al., 1998), boars (Rodrà ­guez-Martà ­nez, 2007; Garner and Johnson, 1995; Garner et al., 1996), rams (Garner and Johnson, 1995), rabbits (Garner and Johnson, 1995), mice (Garner and Johnson, 1995; Songsasen et al., 199 7), poultry and wildfowl (Donoghue et al., 1995; Blanco et al., 2000) and honey bees (Collins and Donoghue, 1999; Collins, 2000) and in fish (Martin Flajshans et al., 2004). Considerable information has accumulated on the use of fluorescent staining protocols for assessing sperm viability (Evenson et al., 1982). The SYBR 14 staining of nucleic acids, especially in the sperm head, was very bright in living sperm. Good agreement was observed between the fluorescent staining method and the standard eosin-nigrosine viability test; the flow cytometric method showed a precision level higher than that of the manual method. One of the first attempts to assess sperm viability utilized rhodamine 123 for determining potentiality of mitochondrial membrane while ethidium bromide for membrane integrity through flow cytometry (Garner et al., 1986). Other combinations that have been used to examine the functional capacity of sperm are carboxyfluorescein diacetate (CFDA) and propidium iodide (PI) (Garner et al., 1988; Watson et al., 1992); carboxydimethylfluorescein diacetate (CMFDA), R123, and PI (Ericsson et al., 1993; Thomas and Garner, 1994); and PI, pisum sativum agglutinin (PSA), and R123 (Graham et al., 1990). The most generally used sperm viability stain combinations is SYBR-14 and PI at present. This stains are now sold commercially as live/dead viability kit. When these two stains are combinely used, the nuclei of viable sperm take fluoresce green and membrane integrity lost cells take red stain. This staining technique has been used in a number of species, including the boar (Garner and Johnson, 1995; Saravia et al.,2005, 2007,2009). Although species differences do exist in the function of spermatozoa, the Live/Dead stain may similarly have no adverse affect on fertilization in the equine, although it remains to be tested in this species. Recently a new instrument (Nucelocounter-SP100) has been introduced to evaluate sperm concentration [11] and viability. Due to the small size and low cost, this instrument has been attracted for field measurements of both concentration and viability. In our hand this instrument was also became useful for the quick measurement of sperm concentration an d viability in stallion (Morrell et al., 2010). Fluorescent probes such as H33258, requiring flow cytometric analysis with a laser that operates in the ultraviolet light range, are less commonly used as this is not a standard feature on the smaller analytical machines. However, one alternative is to use a fluorometer. A fluorometer is a relatively low-cost piece of portable equipment that permits a rapid analysis to be carried out on a sample. Januskauskas et al. (2001) used H33258 to detect nonviable bull spermatozoa by fluorometry and obtained an inverse correlation between the damaged cells per cent and the field fertility. Another option is fluorescent attachments for computer-assisted semen analysis devices. For example, the IDENT fluorescence feature of the Hamilton-Thorne IVOS permits staining with H33258 allowing an assessment of sperm viability to be made along with motility. Fluorochromes used to assess sperm viability by both approach could be utilized in combination with each other. In that case, when CFDA is used combined with PI, three populations of cells as live, which are green; dead, which are red; and a third population which is stained with both and represents dying spermatozoa can be identified. This combination was found useful by Almlid and Johnson (1988) for frozen-thawed boar spermatozoa for monitoring membrane damage at the time of evaluation of various freezing protocols. Further, Harrison and Vickers (1990) also noticed that this combination with a fluorescent microscope is effective indicator of viability of fresh, incubated or cold-shocked spermatozoa in boar and ram. Contrasting to these, Garner et al. (1986) was failed to find a relationship between bull sperm viability and fertility when using combination of CFDA/PI . Flow cytometry for evaluating sperm viability appears to be a precious tool in the AI industry. When a high number of sperm is packed in each insemination dose, the effect of selecting the best ejaculates according to sperm viability has a relatively limited effect. However, sperm viability might be more important when combined with low-dose inseminations. The FACSCount AF flow cytometer also determines sperm concentration accurately and precisely during the same analysis (Christensen et al., 2004a). The combined assessment of sperm viability and concentration appears to be useful in the wake of improving quality control at AI stations. Because of the results of this trial, this method has been implemented by Danish AI stations (Christensen et al., 2005). Relatively bright fluorescence was found also in the mitochondrial sheath of living sperm. But the mechanism and mode of action by which SYBR-14 binds to the DNA of sperm is not known. It is know that PI stains nucleic acids by inte rcalating between the base pairs (Krishan, 1975). Viability stains can also be used in conjugation with fluorescently labeled plant lectins for simultaneous assessment of the plasma membrane integrity and the acrosome integrity (Nagy et al., 2003). It is conceivable that assessment of viability using SYBR-14 dye does not damage spermatozoa, since Garner et al. (5) found that insemination of boar sperm stained with SYBR-14 did not compromise fertilization or even the development of flushed porcine embryos in vitro. Non-viable sperms can be detected using the membrane-impermeable nucleic acid stains which positively identify dead spermatozoa by penetrating cells with damaged membranes. Plasma membrane which is intact will not permit these stains entering into the spermatozoa and staining the nucleus. Most frequently used stains include phenanthridines, for example propidium iodide (PI; (Matyus, 1984) ethidium homodimer-1 (EthD-1; (Althouse et al., 1995), the cyanine Yo-Pro (Kavak, 2003) and the bizbenzimidazole Hoechst 33258 (Gundersen and Shapiro, 1984). After a series of comparison between fertility of cryopreserved stallion spermatozoa with a number of laboratory assessments of semen quality as assessed by flow cytometry using PI, Wilhelm et al. (1996) concluded that viability is the single laboratory assay that correlated with fertility. -Sperm plasma membrane integrity Although the sperm plasma membrane covers the entire cell, it consists of three distinct membrane compartments, one which covers the outer acrosomal membrane, one which covers the post acrosomal portion of the sperm head, and one which covers the middle and principal pieces. Sperm membrane is directly or ind