Make vs Buy Assignment Example | Topics and Well Written Essays - 250 words - 1

Make vs Buy - Assignment Example The restaurant is intended to sell diverse products, which include buffet, pizza, soup, sauces and desserts. In addition, the restaurant will have a self-service soda bar. Although there are other companies such as McDonalds serving the area, the prices of their products are not affordable to most people in Florida. Moreover, these companies do not have physical locations in the area but rely on suppliers. This means that Papa Geo has the potential of competing effectively in the market and possibly gaining competitive advantage (Jeffries & McGrath, 2008). The fact that the products of the company are rare in the market consequently highly demand makes the company more competitive. This will ensure that the company records high sales volume. Moreover, the company will register high sales volume because they produce variety, which gives consumers the ability and freedom of choice. Finally, the company strategy is effective because it attracts children too, which will boost sales since it will be assumed to a family restaurant (Jeffries & McGrath, 2008). The offers given by financial lending institution will be enough in setting up the business and repayment period is reasonable, which will grant the owner the opportunity to repay comfortably. Therefore, the business can be set up but it requires effective analysis and forecasting due to uncertainties in the business environment. Proper financial budgetary planning is fundamental in achieving the company’s strategy. Sale forecast forms the most critical part of this budget proposal because, it is through proper and accurate forecasts in sales that the entrepreneur would be able to determine the amount to repay either in monthly or annual basis. The above sales forecasts are made with the assumptions that one unit in the company goes at $7, and each individual in the 15-minute area purchases one unit

Research paper summary Carrying capacity Example | Topics and Well Written Essays - 500 words

Summary Carrying capacity - Research Paper Example The methodology employed is two pronged as mentioned. The laboratory study was first to be carried out. The study examined various components of the Maculinea arion like its feeding preferences, autumn food consumption and growth and the winter period weight loss. The sample size included a total of 69 caterpillars reared from the onset of their final instars in the late summer to the month of May. In addition, each caterpillar was kept in a seven cubic centimeter plastic box that was furnished with a small piece of moist sponge. During that period, fresh food was supplied to the specimens after every 2-3 days to ensure that there was a surplus in the food given to them. It is also important to note that caterpillars were categorized into different sets with each set provided with a different food type and composition to enable the accurate determination of the objectives of this study. Each caterpillar was also weighed weekly to and kept in a clean box with the resultant weight being recorded for each caterpillar. In addition to the variables obtained in the laboratory set up, published materials were also used for the purposes of the number and biomass of the immature stages of M. sabuleti that were available to final instar caterpillars of Maculinea orion. Finally, estimates were carried out from the mean body weight that was obtained 2 days before eclosion. The field study involved the examination of mortality rates of wild Maculinea arion adopted at different densities into Myrmica sabuleti nest. This was measured during a five-year period study on site X. The study involved the introduction of the caterpillars at different stages of the duration with excavations and counting being done. The obtained data was subsequently being recorded to monitor the changes and effects of the different seasons, eating habits and species behavior. As a combination of the two methods and integration

Terrorists society Essay Example for Free

Terrorists society Essay Perhaps the most known terrorist in the world is Osama Bin Laden. Just as other terrorists of his ilk, there are certain psychological features that are inherent in him. Though it is impossible to study the psychological profile of a single terrorist, researches by psychologists identify a certain trend in their way of thought and actions (Kaplan, 1981). This paper outlines the psychological makeup of terrorists, traits that are observed in Osama Bin Laden. There are certain risk factors that make one highly likely to become a terrorist. These factors combine to give a profile that is general to terrorist the world over. Although a terrorist’s profile can be narrowed down to individuals, there is always a generational transmission of extremist beliefs that starts in early life. A terrorist also feels alienated or oppressed by others in the society. This perceived alienation could be from the locality or at more extended levels as global perspective. A terrorist also has a psychology of being victimized for the ills of the society. Terrorists also believe that any violations by the enemy should be retaliated by equal measure of violence (Post, 2008). The response meted out to the enemy affords the terrorist higher moral standings among his/her peers who regard him/her as a hero. In addition to the above, terrorists believe their ethic, class or social group is special and superior to others and are targeted by others for destruction. Terrorists in most cases lack the political powers to initiate and carry out their plans to success. They therefore turn to violence as the only means of attaining their goals. Terrorists would not carry out their activities if they had no criminal mentality. Moreover, terrorists do not have any fear for death and believe the high esteem from peers is more important than the legacy left behind by dying in the process of carrying out an attack (Hoffman, 1999). Terrorist will always identify with a certain group where the members share the course, suffering, and trauma. At the same time, the group may provide camaraderie and a sense of significance to its members. Historical and Socio-Cultural Antecedents to September 11. Different opinions have been voiced on the most likely antecedents of the 9/11 attacks. These range from religious animosity between Christians and Muslims to the US Occupation of Arab countries and the perceived foreign policies of the American Government. While it is apparent that Al-Qaeda was responsible, theories have been proposed to explain the causes of 9/11 attacks. Some researchers have blamed the Muslim madrasas for instilling a simplistic view of Jihad in young Muslims. Poverty has also been cited as a cause of the 9/11 attacks by a section of world scholars. There have been theories relating the attacks to the democratic principles of the American society, a position vehemently denied by Osama himself. He asked why he did not attack other free-countries such as Sweden. There is also a feeling that efficient funding from wealthy Saudis supported the terrorists in the planning and execution of the attacks. The historical aggressiveness of the U. S towards certain countries due to their oppressive governance and weak systems and institutions has made these countries terrorists’ haven. Decline and stagnation in the Middle East and the humiliation of the Islamic world also led to the attacks. These weak and falling states have been terrorists’ bases from where they plan attacks on real and perceived enemies (Simonsen et al, 2000). In addition to U. S occupation of Arab countries, the clash of civilization between the Arab and American world also led to the attacks. The differences in ideologies such as communism between the U. S. and the Arab world also played a role in causing the attacks. Radicalism resulting from Afghan Jihads against the Soviet Union contributed to the attacks. The generation that participated in the war was radicalized and developed criminal mentality as well. Mental Illness and Terrorism There has been an on-going debate on the role of mental illness in terrorism among scholars. Most studies have dwelt on expert opinions instead of involving the community directly to study the causes of terrorism (Sageman, 2004). This trend has resulted in different conclusions on the role or mental illnesses in terrorism. Most of the studies have failed to factor in on the human vulnerability of the isolated groups and focused on the belief that a terrorist must be mentally unstable to conduct such cruel acts. While some mental experts believe that one should not blame mental illness for terrorist attacks, others feel the mental stability has a role in terrorism. The root causes of terrorism are social factors and not mental illnesses. Mental experts of this line of thought think that psychiatry is not the tool to counter terrorism. Psychiatrists who have tested failed suicide bombers have diagnosed little psychiatric illnesses in violent or mild terrorists. Certain studies have only concentrated on individual instead of the larger terrorism set. Studies should focus on the collective societal needs that compel a group of people to become violent and not on individuals. People become terrorists because of the feeling of being marginalized, oppressed, or targeted by others whom they henceforth consider enemies. Any means to carry out a revenge on such enemies is thus justified. Conclusion Studies have shown a certain mind-set that is inherent in terrorists, albeit in different proportion. Terrorists always see their society to be threatened by others for extinction or victimization based on ideological differences. They react to these notions by violent means that they consider justified provided the intended goals are achieved. They are motivate by the social ills they feel target their society. References Hoffman, B. (1999). Inside Terrorism. NY: Columbia University Press. Kaplan, A. (1981). The psychodynamics of terrorism: Behavioral and quantitative perspectives on terrorism. New York: Pergamon Post, J. M. (2008). The mind of the terrorist: The psychology of terrorism from the IRA to Al-Qaeda. Palgrave Macmillan. Sageman, M. (2004). Understanding terror networks. University of Pennsylvania Press. Simonsen, C. , Spindlove, J. (2000). Terrorism today: the past, the players, the future. NJ: Prentice Hall.

Sperm Assessment Using Flow Cytometry

Sperm Assessment Using Flow Cytometry State of the art in sperm assessment using flow cytometry Abstract Flow cytometry is emerging as an important tool in the field of modern andrology for routine analysis of spermatozoa. Recently, application of flow cytometry in the artificial insemination industry especially for pig is a new approach. Until very recent, semen sample analysis was routinely performed by microscopical evaluation and manual techniques by laboratory operators; the analysis is affected by a wide imprecision related to variability among observers, influencing its clinical validity. The last decade, several new flow cytometric techniques have been introduced for farm animal semen assessment that enable a more detailed evaluation of several sperm characteristics. Here in this paper, an initiative has been taken to focus on a number of recent flow cytometry developments important for addressing questions in andrological tests. After the invention of flow cytometry, sperm evaluation by traditional microscopic means became questioned due to the robust advantages of flow cytometry over the microscopic method. Due to the recent development of large number of fluroscence probes, flow cytometry is now 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 gamets 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 possibility of working with small sample sizes, increases the repeatability of assessment, removes the subjectivity of assessment and allows simultaneous assessment of multiple fluorochromes. Flow cytometry is a technique capable of generating significantly novel data and allows the design and execution of experiments that a re not possible with any other technique. Nowadays, semen evaluation using laboratory assays is extremely important 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 parameters 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 Semen evaluation is the single most important laboratory test that has helped us to identify 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. Methods are available that can sometimes estimate the potential fertilizing capacity of a semen sample and, in some cases, 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). The methods routinely used for evaluation of the quality of a semen sample involved an evaluation of general appearance (i.e. colour, contamination, etc.), volume, pH, sperm concentration, viability, morphology and motility. Most of these techniques are microscopic analyses that only measure a small number of spermatozoa within a population, are time-consuming, can be subjective and generally measure sperm attributes individually. Recently, limitations of semen evaluation methodology have been brought into sharp focus by controversies raised in the epidemiological literature. It should also be noted that such conventional measurements are prone 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 se men, and IVF. Such handling implies semen extension, fluorophore loading, ultraviolet and laser illumination, high-speed sorting, cooling and cryopreservation, procedures that impose different degrees of change in sperm function following damage to sperm membranes, organelles or the DNA. Therefore, although several assays have been developed to monitor these sperm parameters, recently it is being claimed that buck of these procedures are incomplete, time consuming and laborious. Flow cytometry in different technical applications offers many advantages for the analysis of sperm quality. Flow cytometry allows the simultaneous measurement of multiple fluorescences and light scatter induced by illumination of single cell or microscopic particles in suspension, as 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 can acquire data on several subpopulations within a sample in a few minutes, making it ideal for assessment of heterogenous populations in semen sample. Initially developed in the 1960s, flow cytometry made automated separation of cells based on the unique recognition of cellular patterns within a population feasible (Hulett et al., 1969). Using such a separation approach, cellular patterns can be identified by as sessing, in individual cells within a population, protein expression using fluorescently labeled antibodies and other fluorescent probes (Baumgarth and Roederer, 2000; Herzenberg et al., 2006). Flow cytometry was first developed for medical and clinical applications such as haematology and oncology. These areas still account for the vast majority of publications on this technique, but during the past few years it has been used in other areas, such as bioprocess monitoring, pharmacology, toxicology, environmental sciences, bacteriology and virology. Recent advancement of flow cytometry increased its application in the reproductive biology especially for andrology. FCM is increasingly used for basic, clinical, biotechnological, and environmental studies of biochemical relevance. 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. In other word, a flow cytometer will be defined as ‘an instrument that can measure physical, as well as multi-colour fluorescence properties of cells flowing in a stream. In other work, cytometry refers to the measurement of physical and/or chemical characteristics of cells or, by extension, of other particles. It is a process in which such measurements are made while the cells or particles pass, preferably in single file, through the measuring apparatus in a fluid stream. 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 analytical tools, where a single value for each parameter is obtained for the whole population, flow cytometry provides data for 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 gives objective and accurate results (Bunthof et al., 2001; Shleeva et al., 2002), overcoming the problems with the manual methods described above. Function and types of flow cytometry Fluidics, optics and electronics are the three main systems that make up a flow cytometer. In a few minutes, the flow cytometer 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 began when it was used for measuring their DNA content (Evenson et al., 1980) and its application to semen analysis has gradually increased over the last 10-15 years. Flow cytometry is now applied to semen evaluation of traits such as cell viability, acrosomal integrity, mitochondrial function, capacitation status, membrane fluidity and DNA status. New fluorescent stains and techniques are continuously being developed that have potential application to the flow cytometric evaluation of spermatozoa. Flow cytometry permits 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 the more sperm parameters that 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. Sorters have the ability not only to collect data on cells (analyse cells) but also 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 During the past 2 decades, there has been an increasing interest in reliable assays for assessing semen quality in the fertility clinic and artificial insemination industries. The use of flow cytometry for sperm analysis is an attempt to address the long-standing problem of the subjective nature of the manual method commonly used for semen analysis. An additional source of laboratory variation is the low number of sperms analyzed with manual techniques. Because of time and cost restraints, most laboratories analyze only 50 to 100 sperm to compute the percentage of each cell population and the viability rate. This small sample from a population of millions probably results in a statistical sampling error (Russel and Curtis, 1993). The conventional methods used are limited to microscopic determination of sperm concentration using a hemocytometer (Jorgensen et al., 1997) and evaluation of sperm motility and morphology (Keel et al., 2002). These methods usually involve a subjective asses sment of a few hundred sperm, and quality assurance is rarely implemented in the laboratories performing such analysis. Flow cytometry is a technique that is superior to conventional light microscopy techniques in terms of objectivity, number of cells measured, speed, and precision (Spano and Evenson, 1993). The technique has been used on human sperm to determine a number of factors, including membrane integrity, mitochondrial function, acrosome status, and multiparameter measurement (Garrido et al., 2002). Flow cytometry permitted us to analyze thousands of cells in few seconds. 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 diverse species (boar, bull, stallion etc), and the observed CVs were significantly better than those reported for the manual method. While there are many advantages of using the flow cytometer for routine semen analysis, its use is often limited to research by the expense and difficulties of operation associated with the requirement of a skilled operator. In addition, a flow cytometer is quite large and cannot withstand shocks associated with movement, meaning it requires a dedicated position in the laboratory. However, the development of more affordable ‘‘bench-top flow cytometers has recently increased the potential application to semen analysis. If we consider flow cytometric analysis further, we can see that it is gaining wider acceptance as a technique for assessing the acrosome reaction and viability simultaneously. Comparing these assays to the more widely used epifluorescent microscopic techniques, the flow cytometric analysis is able to give a far more simple and objective method of analysis, especially with regard to correlation of fertilization with acrosome reactivity potential (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. Preliminary data from a number of studies suggested 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). Using this information, the World Health Organization stated that ‘‘such chambers, whilst convenient in that they can be used without dilution of the specimen, may lack the accuracy and precision of the haemocytometer technique (World Health Organization, 1999). Further data—for example, from Tomlinson and colleagues—showed that 2 proprietary disposable slides (Microcell, Conception Technologies, San Diego, Calif; Leja, Leja Products, BV Nieuw- Vennep, The Netherlands) gave lower spe rm concentrations compared to the hemocytometer method (Tomlinson et al., 2001). To put this in context, numerous reports document unacceptable discrepancies between different laboratories and even between different individuals, although fewer studies attempt to address these issues. So, what is wrong? Several reports emphasize the need for improvement in overall quality of semen testing within and between laboratories (Neuwinger et al., 1990; Jorgensen et al., 1997; Keel et al., 2000). However, the subjective nature of conventional semen analyses, combined with their relatively low precision due to the low number of cells assessed, leads to poor intra- and interlaboratory reproducibility; therefore, the introduction of standardized or quality controlled procedures will probably have a limited effect. The conventional analyses are used to determine whether parameters obtained from an ejaculate are within the range characterized by fertile men, and these methods can therefore provide only unclear cut-off values when used for the prediction of fertility status. Many of the advantages that accrue when using flow cytometry may, when applied to assessment of sperm cells, help overcome some of the mentioned problems found in conventional semen analysis. In the field of semen analysis, validation of a method is important because it is essential to have specific, precise, objective, and accurate laboratory tests to establish a correlation of the data with fertility or to determine the fertility potential of a semen sample correctly (Amann, 1989). Precision of a laboratory test is of great concern to the andrologist in the fertility clinic, since the results of the semen analysis are often used to advise a patient about his fertility and the prognosis for the treatment of the couple. To use established cut-off values and ensure uniform diagnosis, within and between laboratory variations should be determined and followed closely. Accurate determination of sperm cell concentration is critical to the AI industry because it provides assurance both to bull studs and to customers that straws of extended semen contain the sperm numbers indicated. An accurate measure of sperm concentration is particularly important in export markets 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. Hemacytometers are widely used for routine sperm counts, but the equipment is slow, and multiple measurements of each sample are needed. Single hemacytometer counts are not highly accurate; because of inherent errors in the technique, Freund and Carol (13) found that mean differences of 20% were not uncommon between duplicate sperm count 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 (19). Currently, the primary method used by the AI industry to estimate sperm concentration is spectrophotometric determination of turbidity of a semen sample using an instrument previously calibrated for sperm concentration with a hemacytometer or Coulter counter (1). This approach is only as accurate as the methods used for spectrophotometer calibration. New, more accurate methods for sperm count determinations are being sought to replace the older ones. Some laboratories are trying the Maklerm counting chamber (Seif- 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. It may be argued that when comparing fluorescent microscopy assays with flow cytometry, one is examining patterns of fluorescence rather than fluorescence intensity, i.e., the flow cytometer is not capable of discriminating sperm which have 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 no significant difference between the two 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. Viability 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. Currently flow cytometric procedures have been developed which simultaneously evaluate sperm cell viability, acrosomal integrity and mitochondrial function. 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., 1997), 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 (R123) to assess mitochondrial membrane potential and ethidium bromide to determine membrane integrity using 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). At present, one of the most commonly used viability stain combinations is SYBR-14 and PI, sold commercially as LIVE/DEAD Sperm Viability kit (Molecular Probes Inc., OR, USA). When used in combination, the nuclei of living sperm fluoresce green (SYBR-14) and cells that have lost their membrane integrity stain red (PI). 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 used to evaluate boar sperm concentration [11]. Due to its compact size and its relatively inexpensive purchase price, this instrument could be useful for field measurements of both concentration and viability. This instrument was considered to be a useful instrument for rapidly measuring stallion sperm concentration and viability (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 found a negative correlation between the percentage of damaged cells and 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 either approach can be used in combination with each other. For example, when CFDA is used along with PI, three populations of cells can be identified: live, which are green; dead, which are red; and a third population which is stained with both and represents dying spermatozoa. Almlid and Johnson (1988) found this combination useful for monitoring membrane damage in frozen-thawed boar spermatozoa during evaluation of various freezing protocols. Harrison and Vickers (1990) also used this combination with a fluorescent microscope and found it to be an effective indicator of the viability of fresh, incubated or cold-shocked boar and ram spermatozoa. Garner et al. (1986) used this combination to stain spermatozoa from a number of species, but at that time could not find a relationship between bull sperm viability detected by CFDA/PI and fertility. Flow cytometry for assessment of sperm viability appears to be a valuable tool for 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 on NRR56. 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 combination of assessment of sperm viability and concentration appears to be useful in the improvement of 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. The mechanism by which SYBR-14 binds to the DNA is not known. It is know that PI stains nucleic acids by intercalating betwee n the base pairs (Krishan, 1975). Viability stains have also been used in association with fluorescently labeled plant lectins to simultaneously assess the plasma membrane integrity and the acrosome integrity (Nagy et al., 2003). Assessment of viability using SYBR-14 dye does not damage spermatozoa, since Garner et al. (5) demonstrated that insemination of boar spermatozoa stained with SYBR-14 into sows did not compromise fertilization or the development of flushed porcine embryos in culture. Non-viable cells can be determined using membrane-impermeable nucleic acid stains which positively identify dead spermatozoa by penetrating cells with damaged membranes. An intact plasma membrane will prevent these products from entering the spermatozoa and staining the nucleus. Commonly used examples 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). Wilhelm et al. (1996) compared the fertility of cryopreserved stallion spermatozoa with a number of laboratory assessments of semen quality and found that viability, as assessed by flow cytometry using PI, was the single laboratory assay that correlated with stallion fertility. Changes in sperm membrane permeability Detection of increased membrane permeability is employed in different cell types to distinguish different status of membrane organization (Cohen, 1993; Ormerod et al., 1993; Castaneda and Kinne, 2000; Reber et al., 2002). Sperm plasma membrane status is of utmost importance due to its role, not only as a cell boundary, but also for its need for cell-to-cell interactions, e.g. between spermatozoa and the epithelium of the female genital tract and between the spermatozoon and the oocyte and its vestments (for review, see Rodriguez-Martinez, 2001). Membrane integrity and the stability of its semipermeable features are prerequisites for the viability of the spermatozoon (Rodriguez-Martinez, 2006). However, cryopreservation, whose purpose is to warrant sperm survival, causes irreversible damage to the plasma membrane leading to cell death in a large number of spermatozoa (Holt, 2000) or, in the surviving spermatozoa, to changes similar to those seen during sperm capacitation, thus shorten ing their lifetime (Perez et al., 1996; Cormier et al., 1997; Maxwell and Johnson, 1997; Green and Watson, 2000; Schembri et al., 2000; Watson, 2000). During the freezing process, cells shrink again when cooling rates are slow enough to prevent intracellular ice formation as growing extracellular ice concentrates the solutes in the diminishing volume of non-frozen water, causing intracellular water exosmosis. Though warming and thawing, the cells return to their normal volume. Thus, it is important to know the permeability coefficient of the cells to cryoprotectants, as well as the effect of cryoprotective agents on the membrane hydraulic conductivity. Classical combination of probes allows discrimination of two or three subpopulations of spermatozoa, i.e. live, dead and damaged depending on the degree of membrane integrity (Eriksson RodrÄ ±Ã‚ ´guez-MartÄ ±Ã‚ ´nez, 2000). A new, simple and repeatable method to detect membrane changes in all spermatozoa present in a boar semen sample, by use of markers (combination of SNARF-1, YO-PRO-1 and ethidium homodimer) used to track changes in sperm membrane permeability, has been developed recently by our group (Pena et al., 2005). In determined physiological or pathological situations, live cells are unable to exclude YO-PRO-1, but are still not permeable to other dead-cell discriminatory dyes, like propidium iodide or ethidium homodimer. YO-PRO-1 is an impermeable membrane probe and can leak in, only after destabilization of the membrane, under conditions where ethidium homodimer does not. Because several ATP-dependent channels have been detected in spermatozoa (Acevedo et al. , Sperm Assessment Using Flow Cytometry Sperm Assessment Using Flow Cytometry Abstract Flow cytometry is emerging as an important tool in the field of modern andrology for routine analysis of spermatozoa. Recently, application of flow cytometry in the artificial insemination industry especially for pig is a new approach. Until very recent, semen sample analysis was routinely performed by microscopical evaluation and manual techniques by laboratory operators; the analysis is affected by a wide imprecision related to variability among observers, influencing its clinical validity. The last decade, several new flow cytometric techniques have been introduced for farm animal semen assessment that enable a more detailed evaluation of several sperm characteristics. Here in this paper, an initiative has been taken to focus on a number of recent flow cytometry developments important for addressing questions in andrological tests. After the invention of flow cytometry, sperm evaluation by traditional microscopic means became questioned due to the robust advantages of flow cytometry over the microscopic method. Due to the recent development of large number of fluroscence probes, flow cytometry is now 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 gamets 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 possibility of working with small sample sizes, increases the repeatability of assessment, removes the subjectivity of assessment and allows simultaneous assessment of multiple fluorochromes. Flow cytometry is a technique capable of generating significantly novel data and allows the design and execution of experiments that a re not possible with any other technique. Nowadays, semen evaluation using laboratory assays is extremely important 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 parameters 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 Semen evaluation is the single most important laboratory test that has helped us to identify 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. Methods are available that can sometimes estimate the potential fertilizing capacity of a semen sample and, in some cases, 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). The methods routinely used for evaluation of the quality of a semen sample involved an evaluation of general appearance (i.e. colour, contamination, etc.), volume, pH, sperm concentration, viability, morphology and motility. Most of these techniques are microscopic analyses that only measure a small number of spermatozoa within a population, are time-consuming, can be subjective and generally measure sperm attributes individually. Recently, limitations of semen evaluation methodology have been brought into sharp focus by controversies raised in the epidemiological literature. It should also be noted that such conventional measurements are prone 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 se men, and IVF. Such handling implies semen extension, fluorophore loading, ultraviolet and laser illumination, high-speed sorting, cooling and cryopreservation, procedures that impose different degrees of change in sperm function following damage to sperm membranes, organelles or the DNA. Therefore, although several assays have been developed to monitor these sperm parameters, recently it is being claimed that buck of these procedures are incomplete, time consuming and laborious. Flow cytometry in different technical applications offers many advantages for the analysis of sperm quality. Flow cytometry allows the simultaneous measurement of multiple fluorescences and light scatter induced by illumination of single cell or microscopic particles in suspension, as 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 can acquire data on several subpopulations within a sample in a few minutes, making it ideal for assessment of heterogenous populations in semen sample. Initially developed in the 1960s, flow cytometry made automated separation of cells based on the unique recognition of cellular patterns within a population feasible (Hulett et al., 1969). Using such a separation approach, cellular patterns can be identified by as sessing, in individual cells within a population, protein expression using fluorescently labeled antibodies and other fluorescent probes (Baumgarth and Roederer, 2000; Herzenberg et al., 2006). Flow cytometry was first developed for medical and clinical applications such as haematology and oncology. These areas still account for the vast majority of publications on this technique, but during the past few years it has been used in other areas, such as bioprocess monitoring, pharmacology, toxicology, environmental sciences, bacteriology and virology. Recent advancement of flow cytometry increased its application in the reproductive biology especially for andrology. FCM is increasingly used for basic, clinical, biotechnological, and environmental studies of biochemical relevance. 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. In other word, a flow cytometer will be defined as ‘an instrument that can measure physical, as well as multi-colour fluorescence properties of cells flowing in a stream. In other work, cytometry refers to the measurement of physical and/or chemical characteristics of cells or, by extension, of other particles. It is a process in which such measurements are made while the cells or particles pass, preferably in single file, through the measuring apparatus in a fluid stream. 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 analytical tools, where a single value for each parameter is obtained for the whole population, flow cytometry provides data for 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 gives objective and accurate results (Bunthof et al., 2001; Shleeva et al., 2002), overcoming the problems with the manual methods described above. Function and types of flow cytometry Fluidics, optics and electronics are the three main systems that make up a flow cytometer. In a few minutes, the flow cytometer 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 began when it was used for measuring their DNA content (Evenson et al., 1980) and its application to semen analysis has gradually increased over the last 10-15 years. Flow cytometry is now applied to semen evaluation of traits such as cell viability, acrosomal integrity, mitochondrial function, capacitation status, membrane fluidity and DNA status. New fluorescent stains and techniques are continuously being developed that have potential application to the flow cytometric evaluation of spermatozoa. Flow cytometry permits 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 the more sperm parameters that 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. Sorters have the ability not only to collect data on cells (analyse cells) but also 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 During the past 2 decades, there has been an increasing interest in reliable assays for assessing semen quality in the fertility clinic and artificial insemination industries. The use of flow cytometry for sperm analysis is an attempt to address the long-standing problem of the subjective nature of the manual method commonly used for semen analysis. An additional source of laboratory variation is the low number of sperms analyzed with manual techniques. Because of time and cost restraints, most laboratories analyze only 50 to 100 sperm to compute the percentage of each cell population and the viability rate. This small sample from a population of millions probably results in a statistical sampling error (Russel and Curtis, 1993). The conventional methods used are limited to microscopic determination of sperm concentration using a hemocytometer (Jorgensen et al., 1997) and evaluation of sperm motility and morphology (Keel et al., 2002). These methods usually involve a subjective asses sment of a few hundred sperm, and quality assurance is rarely implemented in the laboratories performing such analysis. Flow cytometry is a technique that is superior to conventional light microscopy techniques in terms of objectivity, number of cells measured, speed, and precision (Spano and Evenson, 1993). The technique has been used on human sperm to determine a number of factors, including membrane integrity, mitochondrial function, acrosome status, and multiparameter measurement (Garrido et al., 2002). Flow cytometry permitted us to analyze thousands of cells in few seconds. 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 diverse species (boar, bull, stallion etc), and the observed CVs were significantly better than those reported for the manual method. While there are many advantages of using the flow cytometer for routine semen analysis, its use is often limited to research by the expense and difficulties of operation associated with the requirement of a skilled operator. In addition, a flow cytometer is quite large and cannot withstand shocks associated with movement, meaning it requires a dedicated position in the laboratory. However, the development of more affordable ‘‘bench-top flow cytometers has recently increased the potential application to semen analysis. If we consider flow cytometric analysis further, we can see that it is gaining wider acceptance as a technique for assessing the acrosome reaction and viability simultaneously. Comparing these assays to the more widely used epifluorescent microscopic techniques, the flow cytometric analysis is able to give a far more simple and objective method of analysis, especially with regard to correlation of fertilization with acrosome reactivity potential (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. Preliminary data from a number of studies suggested 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). Using this information, the World Health Organization stated that ‘‘such chambers, whilst convenient in that they can be used without dilution of the specimen, may lack the accuracy and precision of the haemocytometer technique (World Health Organization, 1999). Further data—for example, from Tomlinson and colleagues—showed that 2 proprietary disposable slides (Microcell, Conception Technologies, San Diego, Calif; Leja, Leja Products, BV Nieuw- Vennep, The Netherlands) gave lower spe rm concentrations compared to the hemocytometer method (Tomlinson et al., 2001). To put this in context, numerous reports document unacceptable discrepancies between different laboratories and even between different individuals, although fewer studies attempt to address these issues. So, what is wrong? Several reports emphasize the need for improvement in overall quality of semen testing within and between laboratories (Neuwinger et al., 1990; Jorgensen et al., 1997; Keel et al., 2000). However, the subjective nature of conventional semen analyses, combined with their relatively low precision due to the low number of cells assessed, leads to poor intra- and interlaboratory reproducibility; therefore, the introduction of standardized or quality controlled procedures will probably have a limited effect. The conventional analyses are used to determine whether parameters obtained from an ejaculate are within the range characterized by fertile men, and these methods can therefore provide only unclear cut-off values when used for the prediction of fertility status. Many of the advantages that accrue when using flow cytometry may, when applied to assessment of sperm cells, help overcome some of the mentioned problems found in conventional semen analysis. In the field of semen analysis, validation of a method is important because it is essential to have specific, precise, objective, and accurate laboratory tests to establish a correlation of the data with fertility or to determine the fertility potential of a semen sample correctly (Amann, 1989). Precision of a laboratory test is of great concern to the andrologist in the fertility clinic, since the results of the semen analysis are often used to advise a patient about his fertility and the prognosis for the treatment of the couple. To use established cut-off values and ensure uniform diagnosis, within and between laboratory variations should be determined and followed closely. Accurate determination of sperm cell concentration is critical to the AI industry because it provides assurance both to bull studs and to customers that straws of extended semen contain the sperm numbers indicated. An accurate measure of sperm concentration is particularly important in export markets 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. Hemacytometers are widely used for routine sperm counts, but the equipment is slow, and multiple measurements of each sample are needed. Single hemacytometer counts are not highly accurate; because of inherent errors in the technique, Freund and Carol (13) found that mean differences of 20% were not uncommon between duplicate sperm count 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 (19). Currently, the primary method used by the AI industry to estimate sperm concentration is spectrophotometric determination of turbidity of a semen sample using an instrument previously calibrated for sperm concentration with a hemacytometer or Coulter counter (1). This approach is only as accurate as the methods used for spectrophotometer calibration. New, more accurate methods for sperm count determinations are being sought to replace the older ones. Some laboratories are trying the Maklerm counting chamber (Seif- 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. It may be argued that when comparing fluorescent microscopy assays with flow cytometry, one is examining patterns of fluorescence rather than fluorescence intensity, i.e., the flow cytometer is not capable of discriminating sperm which have 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 no significant difference between the two 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. Viability 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. Currently flow cytometric procedures have been developed which simultaneously evaluate sperm cell viability, acrosomal integrity and mitochondrial function. 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., 1997), 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 (R123) to assess mitochondrial membrane potential and ethidium bromide to determine membrane integrity using 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). At present, one of the most commonly used viability stain combinations is SYBR-14 and PI, sold commercially as LIVE/DEAD Sperm Viability kit (Molecular Probes Inc., OR, USA). When used in combination, the nuclei of living sperm fluoresce green (SYBR-14) and cells that have lost their membrane integrity stain red (PI). 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 used to evaluate boar sperm concentration [11]. Due to its compact size and its relatively inexpensive purchase price, this instrument could be useful for field measurements of both concentration and viability. This instrument was considered to be a useful instrument for rapidly measuring stallion sperm concentration and viability (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 found a negative correlation between the percentage of damaged cells and 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 either approach can be used in combination with each other. For example, when CFDA is used along with PI, three populations of cells can be identified: live, which are green; dead, which are red; and a third population which is stained with both and represents dying spermatozoa. Almlid and Johnson (1988) found this combination useful for monitoring membrane damage in frozen-thawed boar spermatozoa during evaluation of various freezing protocols. Harrison and Vickers (1990) also used this combination with a fluorescent microscope and found it to be an effective indicator of the viability of fresh, incubated or cold-shocked boar and ram spermatozoa. Garner et al. (1986) used this combination to stain spermatozoa from a number of species, but at that time could not find a relationship between bull sperm viability detected by CFDA/PI and fertility. Flow cytometry for assessment of sperm viability appears to be a valuable tool for 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 on NRR56. 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 combination of assessment of sperm viability and concentration appears to be useful in the improvement of 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. The mechanism by which SYBR-14 binds to the DNA is not known. It is know that PI stains nucleic acids by intercalating betwee n the base pairs (Krishan, 1975). Viability stains have also been used in association with fluorescently labeled plant lectins to simultaneously assess the plasma membrane integrity and the acrosome integrity (Nagy et al., 2003). Assessment of viability using SYBR-14 dye does not damage spermatozoa, since Garner et al. (5) demonstrated that insemination of boar spermatozoa stained with SYBR-14 into sows did not compromise fertilization or the development of flushed porcine embryos in culture. Non-viable cells can be determined using membrane-impermeable nucleic acid stains which positively identify dead spermatozoa by penetrating cells with damaged membranes. An intact plasma membrane will prevent these products from entering the spermatozoa and staining the nucleus. Commonly used examples 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). Wilhelm et al. (1996) compared the fertility of cryopreserved stallion spermatozoa with a number of laboratory assessments of semen quality and found that viability, as assessed by flow cytometry using PI, was the single laboratory assay that correlated with stallion fertility. Changes in sperm membrane permeability Detection of increased membrane permeability is employed in different cell types to distinguish different status of membrane organization (Cohen, 1993; Ormerod et al., 1993; Castaneda and Kinne, 2000; Reber et al., 2002). Sperm plasma membrane status is of utmost importance due to its role, not only as a cell boundary, but also for its need for cell-to-cell interactions, e.g. between spermatozoa and the epithelium of the female genital tract and between the spermatozoon and the oocyte and its vestments (for review, see Rodriguez-Martinez, 2001). Membrane integrity and the stability of its semipermeable features are prerequisites for the viability of the spermatozoon (Rodriguez-Martinez, 2006). However, cryopreservation, whose purpose is to warrant sperm survival, causes irreversible damage to the plasma membrane leading to cell death in a large number of spermatozoa (Holt, 2000) or, in the surviving spermatozoa, to changes similar to those seen during sperm capacitation, thus shorten ing their lifetime (Perez et al., 1996; Cormier et al., 1997; Maxwell and Johnson, 1997; Green and Watson, 2000; Schembri et al., 2000; Watson, 2000). During the freezing process, cells shrink again when cooling rates are slow enough to prevent intracellular ice formation as growing extracellular ice concentrates the solutes in the diminishing volume of non-frozen water, causing intracellular water exosmosis. Though warming and thawing, the cells return to their normal volume. Thus, it is important to know the permeability coefficient of the cells to cryoprotectants, as well as the effect of cryoprotective agents on the membrane hydraulic conductivity. Classical combination of probes allows discrimination of two or three subpopulations of spermatozoa, i.e. live, dead and damaged depending on the degree of membrane integrity (Eriksson RodrÄ ±Ã‚ ´guez-MartÄ ±Ã‚ ´nez, 2000). A new, simple and repeatable method to detect membrane changes in all spermatozoa present in a boar semen sample, by use of markers (combination of SNARF-1, YO-PRO-1 and ethidium homodimer) used to track changes in sperm membrane permeability, has been developed recently by our group (Pena et al., 2005). In determined physiological or pathological situations, live cells are unable to exclude YO-PRO-1, but are still not permeable to other dead-cell discriminatory dyes, like propidium iodide or ethidium homodimer. YO-PRO-1 is an impermeable membrane probe and can leak in, only after destabilization of the membrane, under conditions where ethidium homodimer does not. Because several ATP-dependent channels have been detected in spermatozoa (Acevedo et al. , 2006), it seems plausible that this is a result of the silencing of a multidrug transporter. This m

Movie Review: Yentl Essay -- essays research papers

Movie Review: Yentl Everyone at one time or another has felt out of place. Feeling unsure of one's place in society is an experience that every young adult faces but deals with differently. Some rebel while others comply with whatever has been set out for them by society or their parents, or both. The role of the woman in society is forever changing. Where women were once obligated to stay in the home and dote on their husbands, they are now working in the same types of jobs as their husbands. What was typically the male role has been blurred and practically obliterated. Religious roles have followed society's lead in their evolution. For example, since its creation over five thousand years ago, the Jewish religion has evolved in some movements to involve women and men equally in ceremonies. The orthodox movement has always remained traditional in its belief that women have their place in the home, cooking and raising children, and serving their husbands. Education remains the man's duty. The movie Yentl starring Barbara Streisand, shows this traditional belief through its plot, characterization, music, lights, camera angles, and symbolism. Set in Eastern Europe in 1904, Yentl captures the essence of the Jewish woman's eternal struggle. It is the story of a young girl, in love with learning but forbidden to do so by Jewish tradition. Upon her father's death, Yentl disguises herself as a boy to attend a yeshiva (religious school) and continue her studies. She befriends Avigdor, a male scholar at the yeshiva, and falls in love with him. Driven by her love for him, Yentl will do all that she can to ensure that he is near her and that her secret is not revealed. Yentl struggles with her secret until the day she can no longer remain silent. She tells Avigdor what she has done, and of her love for him, but he cannot accept a woman who refuses to act as a traditional woman should. So Yentl departs for America in hope of a different mentality, but never forgetting her love for Avigdor and all that she has learned. Based on Isaac Bashevis Singer's acclaimed short story, "Yentl, the Yeshiva Boy," the story is somewhat unrealistic but serves its purpose in proving a point; the point being that women have always been just as capable as men in studying and education, an... ...e bird, is able to soar - through the prejudices of her traditions and through the world of knowledge for which she so longs. She displays this thought in the last line of the movie when she sings "Papa watch me fly." As well, when Yentl transforms herself into Anshel, the boy, she looks at herself in a cracked mirror and cuts her hair. This displays her uncertainty of herself and her place in Jewish society, and the cutting of her hair symbolizes her transformation and the beginning of a new life for her. Symbolism throughout the film, contributes to the film's theme of self-discovery and role reversal. The plot, characterization, lighting, camera angles, and symbolism reveal thoroughly the plot of this highly thought-evoking film. The plot mainly contributes to proving that a woman's place is not solely in the home. That "story books for women, sacred books for men", as the bookseller says at the beginning of the story, is not an accurate assessment of a woman's intellectual capabilities. Because of Barbara Streisand's fabulous and complete characterization of Yentl, this movie comes to life and touches the hearts of its viewers.

Poems from the Kokinshu: A Literary Analysis Essay

Poems from the Kokinshu is an anthology of poems from the Japanese medieval times (Lawall. ed, 2002). The anthology is divided into different poems depicting human emotions as they vary season after season, or as people move into an entirely new environment. The principal theme of the poems revolve around the concept of love—the progression of feelings, the â€Å"entire course of the love affair, early yearnings, passionate meetings, sadness and regret† (Rodd and Henkenius, 1996). As each season, starting from spring, progresses, the emotions entailed in each poem also changes and develops. One of the principal stylistic features in the anthology is simile, wherein the author compares his feelings to his observation of what is happening in his environment. An example of simile is expressed in Poem II, 73: â€Å"like the world hollow as a cicada’s cast-off shell– oh cherry blossoms– you too will fade away just as we catch sight of your beauty† In this particular poem, the author compares his object of affection to a decaying shell of the cicada as the day turns into night. Simile occurs in several poems just like the said example. Another striking stylistic feature presented in the poem is antithesis, wherein the author expresses his emotions in contrast to his environment. In several poems wherein the prevailing emotion is grief, the author contrasts his feelings to the beauty of his environment. Here is an example from Poems 7 and 8 from the Spring Poems of the Kokinshu: â€Å"so longingly have I awaited the fresh flowers of spring, that they have dyed my soul and I see snow as clustered blooms on branches though I bask in the comforting warmth of spring’s light how melancholy to think that my hair now wears a crown of winter snow† Aside from the aforementioned poems being examples of antithesis, parts of them also suggest allegory. The phrases â€Å"they have dyed my soul† and â€Å"to think that my hair now wears a crown of winter snow† mean that the character in the poem is old and has white hair. The antithesis comes as he describes the warmth of spring in contrast to the cold winter which his body and soul are experiencing, i. e. , his old age. Given that the anthology was written and compiled in the Japanese medieval times, the concepts or theme presented in The Kokinshu are parallel to other literary works done in different parts of the world, such as the Medieval Lyrics of the English Literature. Though a significant number of these lyrics talk about Christianity and religion, most works are also written in the concept of love with a pretext of nature. An example of a Medieval Lyric similar to the theme of a Kokinshu poem is Westron Wind (Western Wind): â€Å"Westron wind, when will thou blow? The small rain down can rain. Christ, if my love were in my arms, And I in my bed again. † As said earlier, the prevailing concept tackled in the anthology is love and its accompanying emotions that were given color and described in comparison/contrast to nature and its seasons. The concept of love, though internationally recognized throughout the centuries and millennium, is somewhat a secondary concept in the 21st century. In this day and age, with all the prevailing issues such as technology, globalization and others, the concept of love is deemed unimportant to be tackled, although, it is indeed, as cliche dictates, the universal language. As Mario Vargas Llosa said, literature is â€Å"one of the common denominators of human experience through which human beings may recognize themselves and converse with each other, no matter how different their professions, their life plans, their geographical and cultural locations, their personal circumstances. † Although the concept of love is not deemed as important as business or political concepts nowadays, it still is a ruling emotion that affects each person. Any person who has loved or wanted to love, or even despised love, can relate to the verses of the Kokinshu, including myself. References Lawall, S. N. (Ed. ) (2002). The Norton Anthology of World Literature. New York: WW Norton & Co, Inc. Rodd, L. R. , & Henkenius, M. C. (Eds. ) (1996). Kokinshu: A Collection of Poems Ancient

S.I.P sample

As of the mosquito, citronella can really repel it, and it is now proven by scientists. But as of the ants and the flies, we are trying to work on a simple experiment in which it can repel or kill them.Objectives: 1 . ) We used our classroom as the scenario, and as we all know, there are many ants, flies and mosquitoes in it. And we can't concentrate in what we are doing because of them. So, we conducted this s. I. P. To make us comfortable in our room without disruptions Just to kill mosquitoes, flies and ants. 2. ) We can also use this in our houses, if there are infestations of mosquitoes, ants or flies. 3. This liquid is not smelly as the others are, so you can breathe well even spraying it. 4. ) Our project only uses organic materials and we don't use Cuff's that can destroy our ozone. Significance: Our project might not be the first project to kill mosquitoes, flies and ants, but our only uses organic materials which is not common in making project insecticides. We decided to m ake this project for us to create our own version of organic insecticides.Our project is important nowadays because almost all of the commodities are now expensive, and we need to use our available resources as an alternative to all. And we chose to create an insecticides. Scope and limitations: alternative of In other insecticides, they can also kill cockroaches and even mice, but we chose not to our members because when we discussed how to conduct the experiment of it, one of suggested that we would be having a hard time catching cockroaches and mice, and we've all agreed to this.