numerous other treaties and bodies were created to regulate the conduct of states towards one another in terms of these treaties, including, but not limited to, the permanent court of arbitration in 1899 ; the hague and geneva conventions, the first of which was passed in 1907 ; the international court of justice in 1921 ; the genocide convention ; and the international criminal court, in the late 1990s. because international law is a relatively new area of law its development and propriety in applicable areas are often subject to dispute. international law sources under article 38 of the statute of the international court of justice, public international law has three principal sources : international treaties, custom, and general principles of law. in addition, judicial decisions and teachings may be applied as " subsidiary means for the determination of rules of law ". international treaty law comprises obligations states expressly and voluntarily accept between themselves in treaties. customary international law is derived from the consistent practice of states accompanied by opinio juris, i. e. the conviction of states that the consistent practice is required by a legal obligation. judgments of international tribunals as well as scholarly works have traditionally been looked to as persuasive sources for custom in addition to direct evidence of state behavior. attempts to codify customary international law picked up momentum after the second world war with the formation of the international law commission ( ilc ), under the aegis of the united nations. codified customary law is made the binding interpretation of the underlying custom by agreement through treaty. for states not party to such treaties, the work of the ilc may still be accepted as custom applying to those states. general principles of law are those commonly recognized by the major legal systems of the world. certain norms of international law achieve the binding force of peremptory norms ( jus cogens ) as to include all states with no permissible derogations. international treaties where there are disputes about the exact meaning and application of national laws, it is the responsibility of the courts to decide what the law means. in international law interpretation is within the domain of the protagonists, but may also be conferred on judicial bodies such as the international court of justice, by the terms of the treaties or by consent of the parties. it is generally the responsibility of states to interpret the law for themselves, but the processes of diplomacy and availability of supra - national judicial organs operate routinely to provide assistance to that end. insofar as treaties are concerned, the vienna convention on the law of treaties writes on the topic of interpretation that : - " a treaty shall be interpreted


and availability of supra - national judicial organs operate routinely to provide assistance to that end. insofar as treaties are concerned, the vienna convention on the law of treaties writes on the topic of interpretation that : - " a treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose. " ( article 31 ( 1 ) ) this is actually a compromise between three different theories of interpretation : - the textual approach, a restrictive interpretation, which bases itself on the " ordinary meaning " of the text ; that approach assigns considerable weight to the actual text. - the subjective approach, which takes into consideration i. the idea behind the treaty, ii. treaties " in their context ", and iii. what the writers intended when they wrote the text. - a third approach, which bases itself on interpretation " in the light of its object and purpose ", i. e. the interpretation that best suits the goal of the treaty, also called " effective interpretation ". these are general rules of interpretation ; specific rules might exist in specific areas of international law. statehood and responsibility public international law establishes the framework and the criteria for identifying states as the principal actors in the international legal system. as the existence of a state presupposes control and jurisdiction over territory, international law deals with the acquisition of territory, state immunity and the legal responsibility of states in their conduct with each other. international law is similarly concerned with the treatment of individuals within state boundaries. there is thus a comprehensive regime dealing with group rights, the treatment of aliens, the rights of refugees, international crimes, nationality problems, and human rights generally. it further includes the important functions of the maintenance of international peace and security, arms control, the pacific settlement of disputes and the regulation of the use of force in international relations. even when the law is not able to stop the outbreak of war, it has developed principles to govern the conduct of hostilities and the treatment of prisoners. international law is also used to govern issues relating to the global environment, the global commons such as international waters and outer space, global communications, and world trade. in theory all states are sovereign and equal. as a result of the notion of sovereignty, the value and authority of international law is dependent upon the voluntary participation of states in its formulation, observance, and enforcement. although there may be exceptions, it is thought by many international academics that most states enter into legal commitments with other states out of enlight


authority of international law is dependent upon the voluntary participation of states in its formulation, observance, and enforcement. although there may be exceptions, it is thought by many international academics that most states enter into legal commitments with other states out of enlightened self - interest rather than adherence to a body of law that is higher than their own. as d. w. greig notes, " international law cannot exist in isolation from the political factors operating in the sphere of international relations ". traditionally, sovereign states and the holy see were the sole subjects of international law. with the proliferation of international organizations over the last century, they have in some cases been recognized as relevant parties as well. recent interpretations of international human rights law, international humanitarian law, and international trade law ( e. g., north american free trade agreement ( nafta ) chapter 11 actions ) have been inclusive of corporations, and even of certain individuals. | this section requires expansion. ( october 2012 ) | national sovereignty the conflict between international law and national sovereignty is subject to vigorous debate and dispute in academia, diplomacy, and politics. certainly, there is a growing trend toward judging a state ' s domestic actions in the light of international law and standards. numerous people now view the nation - state as the primary unit of international affairs, and believe that only states may choose to voluntarily enter into commitments under international law, and that they have the right to follow their own counsel when it comes to interpretation of their commitments. certain scholars [ who? ] and political leaders feel that these modern developments endanger nation states by taking power away from state governments and ceding it to international bodies such as the u. n. and the world bank, argue that international law has evolved to a point where it exists separately from the mere consent of states, and discern a legislative and judicial process to international law that parallels such processes within domestic law. this especially occurs when states violate or deviate from the expected standards of conduct adhered to by all civilized nations. a number of states place emphasis on the principle of territorial sovereignty, thus seeing states as having free rein over their internal affairs. other states oppose this view. one group of opponents of this point of view, including many european nations, maintain that all civilized nations have certain norms of conduct expected of them, including the prohibition of genocide, slavery and the slave trade, wars of aggression, torture, and piracy, and that violation of these universal norms represents a crime, not only against the individual victims, but against humanity as a whole. states


of them, including the prohibition of genocide, slavery and the slave trade, wars of aggression, torture, and piracy, and that violation of these universal norms represents a crime, not only against the individual victims, but against humanity as a whole. states and individuals who subscribe to this view opine that, in the case of the individual responsible for violation of international law, he " is become, like the pirate and the slave trader before him, hostis humani generis, an enemy of all mankind ", and thus subject to prosecution in a fair trial before any fundamentally just tribunal, through the exercise of universal jurisdiction. though the european democracies tend to support broad, universalistic interpretations of international law, many other democracies have differing views on international law. several democracies, including india, israel and the united states, take a flexible, eclectic approach, recognizing aspects of public international law such as territorial rights as universal, regarding other aspects as arising from treaty or custom, and viewing certain aspects as not being subjects of public international law at all. democracies in the developing world, due to their past colonial histories, often insist on non - interference in their internal affairs, particularly regarding human rights standards or their peculiar institutions, but often strongly support international law at the bilateral and multilateral levels, such as in the united nations, and especially regarding the use of force, disarmament obligations, and the terms of the un charter. international human rights - universal declaration of human rights - declaration of fundamental rights at work - international labour organization international economic law | this section requires expansion. ( october 2012 ) | war and conflicts | this section requires expansion. ( october 2012 ) | international criminal law | this section requires expansion. ( october 2012 ) | international courts and enforcement it is probably the case that almost all nations observe almost all principles of international law and almost all of their obligations almost all the time. since international law has no established compulsory judicial system for the settlement of disputes or a coercive penal system, it is not as straightforward as managing breaches within a domestic legal system. however, there are means by which breaches are brought to the attention of the international community and some means for resolution. for example, there are judicial or quasi - judicial tribunals in international law in certain areas such as trade and human rights. the formation of the united nations, for example, created a means for the world community to enforce international law upon members that violate its charter through the security council. since international law exists in a legal environment


in certain areas such as trade and human rights. the formation of the united nations, for example, created a means for the world community to enforce international law upon members that violate its charter through the security council. since international law exists in a legal environment without an overarching " sovereign " ( i. e., an external power able and willing to compel compliance with international norms ), " enforcement " of international law is very different than in the domestic context. in many cases, enforcement takes on coasian characteristics, where the norm is self - enforcing. in other cases, defection from the norm can pose a real risk, particularly if the international environment is changing. when this happens, and if enough states ( or enough powerful states ) continually ignore a particular aspect of international law, the norm may actually change according to concepts of customary international law. for example, prior to world war i, unrestricted submarine warfare was considered a violation of international law and ostensibly the casus belli for the united states ' declaration of war against germany. by world war ii, however, the practice was so widespread that during the nuremberg trials, the charges against german admiral karl donitz for ordering unrestricted submarine warfare were dropped, notwithstanding that the activity constituted a clear violation of the second london naval treaty of 1936. enforcement by states apart from a state ' s natural inclination to uphold certain norms, the force of international law comes from the pressure that states put upon one another to behave consistently and to honor their obligations. as with any system of law, many violations of international law obligations are overlooked. if addressed, it may be through diplomacy and the consequences upon an offending state ' s reputation, submission to international judicial determination, arbitration, sanctions or force including war. though violations may be common in fact, states try to avoid the appearance of having disregarded international obligations. states may also unilaterally adopt sanctions against one another such as the severance of economic or diplomatic ties, or through reciprocal action. in some cases, domestic courts may render judgment against a foreign state ( the realm of private international law ) for an injury, though this is a complicated area of law where international law intersects with domestic law. it is implicit in the westphalian system of nation - states, and explicitly recognized under article 51 of the charter of the united nations, that all states have the inherent right to individual and collective self - defense if an armed attack occurs against them. article 51 of the un charter guarantees the right of states to defend themselves until ( and unless ) the security


the charter of the united nations, that all states have the inherent right to individual and collective self - defense if an armed attack occurs against them. article 51 of the un charter guarantees the right of states to defend themselves until ( and unless ) the security council takes measures to keep the peace. enforcement by international bodies violations of the un charter by members of the united nations may be raised by the aggrieved state in the general assembly for debate. the general assembly cannot make binding resolutions, only ' recommendations ', but through its adoption of the " uniting for peace " resolution ( a / res / 377 a ), of 3 november 1950, the assembly declared that it has the power to authorize the use of force, under the terms of the un charter, in cases of breaches of the peace or acts of aggression, provided that the security council, owing to the negative vote of a permanent member, fails to act to address the situation. the assembly also declared, by its adoption of resolution 377 a, that it could call for other collective measures — such as economic and diplomatic sanctions — in situations constituting the milder " threat to the peace ". the uniting for peace resolution was initiated by the united states in 1950, shortly after the outbreak of the korean war, as a means of circumventing possible future soviet vetoes in the security council. the legal significance of the resolution is unclear, given that the general assembly cannot issue binding resolutions. however, it was never argued by the " joint seven - powers " that put forward the draft resolution, during the corresponding discussions, that it in any way afforded the assembly new powers. instead, they argued that the resolution simply declared what the assembly ' s powers already were, according to the un charter, in the case of a dead - locked security council. the soviet union was the only permanent member of the security council to vote against the charter interpretations that were made law by the assembly ' s adoption of resolution 377 a. alleged violations of the charter can also be raised by states in the security council. the security council could subsequently pass resolutions under chapter vi of the un charter to recommend the " pacific resolution of disputes. " such resolutions are not binding under international law, though they usually are expressive of the council ' s convictions. in rare cases, the security council can adopt resolutions under chapter vii of the un charter, related to " threats to peace, breaches of the peace and acts of aggression, " which are legally binding under international law, and can be followed up with


in rare cases, the security council can adopt resolutions under chapter vii of the un charter, related to " threats to peace, breaches of the peace and acts of aggression, " which are legally binding under international law, and can be followed up with economic sanctions, military action, and similar uses of force through the auspices of the united nations. it has been argued that resolutions passed outside of chapter vii can also be binding ; the legal basis for that is the council ' s broad powers under article 24 ( 2 ), which states that " in discharging these duties ( exercise of primary responsibility in international peace and security ), it shall act in accordance with the purposes and principles of the united nations ". the mandatory nature of such resolutions was upheld by the international court of justice ( icj ) in its advisory opinion on namibia. the binding nature of such resolutions can be deduced from an interpretation of their language and intent. states can also, upon mutual consent, submit disputes for arbitration by the international court of justice, located in the hague, netherlands. the judgments given by the court in these cases are binding, although it possesses no means to enforce its rulings. the court may give an advisory opinion on any legal question at the request of whatever body may be authorized by or in accordance with the charter of the united nations to make such a request. some of the advisory cases brought before the court have been controversial with respect to the court ' s competence and jurisdiction. often enormously complicated matters, icj cases ( of which there have been less than 150 since the court was created from the permanent court of international justice in 1945 ) can stretch on for years and generally involve thousands of pages of pleadings, evidence, and the world ' s leading specialist public international lawyers. as of june 2009, there are 15 cases pending at the icj. decisions made through other means of arbitration may be binding or non - binding depending on the nature of the arbitration agreement, whereas decisions resulting from contentious cases argued before the icj are always binding on the involved states. though states ( or increasingly, international organizations ) are usually the only ones with standing to address a violation of international law, some treaties, such as the international covenant on civil and political rights have an optional protocol that allows individuals who have had their rights violated by member states to petition the international human rights committee. investment treaties commonly and routinely provide for enforcement by individuals or investing entities. and commercial agreements of foreigners with sovereign governments may be enforced on the international plane. international legal theory international legal theory comprises a


violated by member states to petition the international human rights committee. investment treaties commonly and routinely provide for enforcement by individuals or investing entities. and commercial agreements of foreigners with sovereign governments may be enforced on the international plane. international legal theory international legal theory comprises a variety of theoretical and methodological approaches used to explain and analyse the content, formation and effectiveness of public international law and institutions and to suggest improvements. some approaches center on the question of compliance : why states follow international norms in the absence of a coercitive power that ensures compliance. other approaches focus on the problem of the formation of international rules : why states voluntarily adopt international law norms, that limit their freedom of action, in the absence of a world legislature ; while other perspectives are policy oriented : they elaborate theoretical frameworks and instruments to criticize the existing norms and to make suggestions on how to improve them. some of these approaches are based on domestic legal theory, some are interdisciplinary, and others have been developed expressly to analyse international law. classical approaches to international legal theory are the natural law, the eclectic and the legal positivism schools of thought. natural law the natural law approach argues that international norms should be based on axiomatic truths. 16th century natural law writer, francisco de vitoria, a professor of theology at the university of salamanca, examined the questions of the just war, the spanish authority in the americas, and the rights of the native american peoples. eclectic or grotian school in 1625 hugo grotius argued that nations as well as persons ought to be governed by universal principle based on morality and divine justice while the relations among polities ought to be governed by the law of peoples, the jus gentium, established by the consent of the community of nations on the basis of the principle of pacta sunt servanda, that is, on the basis of the observance of commitments. on his part, emmerich de vattel argued instead for the equality of states as articulated by 18th century natural law and suggested that the law of nations was composed of custom and law on the one hand, and natural law on the other. during the 17th century, the basic tenets of the grotian or eclectic school, especially the doctrines of legal equality, territorial sovereignty, and independence of states, became the fundamental principles of the european political and legal system and were enshrined in the 1648 peace of westphalia. legal positivism the early positivist school emphasized the importance of custom and treaties as sources of international law. 16th century


, became the fundamental principles of the european political and legal system and were enshrined in the 1648 peace of westphalia. legal positivism the early positivist school emphasized the importance of custom and treaties as sources of international law. 16th century alberico gentili used historical examples to posit that positive law ( jus voluntarium ) was determined by general consent. cornelius van bynkershoek asserted that the bases of international law were customs and treaties commonly consented to by various states, while john jacob moser emphasized the importance of state practice in international law. the positivism school narrowed the range of international practice that might qualify as law, favouring rationality over morality and ethics. the 1815 congress of vienna marked the formal recognition of the political and international legal system based on the conditions of europe. modern legal positivists consider international law as a unified system of rules that emanates from the states ' will. international law, as it is, is an " objective " reality that needs to be distinguished from law " as it should be. " classic positivism demands rigorous tests for legal validity and it deems irrelevant all extralegal arguments. see also - consular law - diplomatic law - international aviation law - international criminal law - international environmental law - international human rights law - international humanitarian law - international space law - international trade law - law of state responsibility - rule according to higher law - united nations convention on the law of the sea - use of force continuum - diplomatic recognition - environmental agreements - global administrative law - international community - international court of justice - international criminal court - international criminal tribunal for rwanda - international criminal tribunal for the former yugoslavia - international labour organization - international law commission - international legal theory - hans kelsen - laws of war - legal status of the holy see - list of international public law topics - list of treaties - personal jurisdiction over international defendants in the united states - prize law - sources of international law - sovereign state - territorial integrity - third world approaches to international law ( twail ) - united nations - united nations general assembly sixth committee ( legal ) - university for peace - world government - history of public international law - columbia law school, mckeever, 2003 — definition of international law - greig, d. w., international law, 2nd edn ( butterworths : london, 1976 ) - janis, m. and noyes, j. international law " : cases and commentary ( 3rd ed. ), prosecutor v. furundzi


. w., international law, 2nd edn ( butterworths : london, 1976 ) - janis, m. and noyes, j. international law " : cases and commentary ( 3rd ed. ), prosecutor v. furundzija, page 148 ( 2006 ) - henkin, louis ( 1968 ). how nations behave. p. 47. - united states, united kingdom, france, canada, turkey, philippines and uruguay - united nations general assembly proces verbal session 5 on 1 november 1950 ( retrieved 2008 - 04 - 13 ) - united nations general assembly proces verbal session 5 on 2 november 1950 ( retrieved 2008 - 04 - 13 ) - united nations general assembly proces verbal session 5 on 2 november 1950 ( retrieved 2008 - 04 - 13 ) - united nations general assembly proces verbal session 5 on 3 november 1950 ( retrieved 2008 - 04 - 13 ) - bruno simma and andreas l. paulus " symposium on method in international law : the responsibility of individuals for human rights abuses in internal conflicts : a positivist view " 93 american journal of international law 302 ( april, 1999 ) - i. brownlie, principles of public international law ( 7th edn oxford university press 2008 ) isbn 0199260710 - dominique carreau, droit international, pedone, 10e edition, 2009 isbn 9782233005618. - p. - m. dupuy & y. kerbrat, " droit international public " ( 10th ed., paris, dalloz, 2010 ) isbn 9782247088935 - e. lawson, and ml bertucci, encyclopedia of human rights ( 2nd edn taylor & francis 1996 ) - e. osmanczyk, the encyclopedia of the united nations and international relations ( taylor & francis 1990 ) - m. n. shaw, international law ( 5th edn cambridge university press 2003 ) - rafael domingo osle, the new global law ( cambridge university press 2010 ) - public international law – resources - a brief primer on international law with cases and commentary. nathaniel burney, 2007. - american society of international law – 100 ways international law shapes our lives - department of public international law, graduate institute of international and development studies, geneva - american society of international law – resource guide ( introduction ) - international law details - international law observer – blog dedicated to reports and commentary on international law - official united nations website - official un website on international law - official website of the international court of justice - opini


support vector machine in machine learning, support vector machines ( svms, also support vector networks ) are supervised learning models with associated learning algorithms that analyze data and recognize patterns, used for classification and regression analysis. the basic svm takes a set of input data and predicts, for each given input, which of two possible classes forms the output, making it a non - probabilistic binary linear classifier. given a set of training examples, each marked as belonging to one of two categories, an svm training algorithm builds a model that assigns new examples into one category or the other. an svm model is a representation of the examples as points in space, mapped so that the examples of the separate categories are divided by a clear gap that is as wide as possible. new examples are then mapped into that same space and predicted to belong to a category based on which side of the gap they fall on. in addition to performing linear classification, svms can efficiently perform non - linear classification using what is called the kernel trick, implicitly mapping their inputs into high - dimensional feature spaces. formal definition more formally, a support vector machine constructs a hyperplane or set of hyperplanes in a high - or infinite - dimensional space, which can be used for classification, regression, or other tasks. intuitively, a good separation is achieved by the hyperplane that has the largest distance to the nearest training data point of any class ( so - called functional margin ), since in general the larger the margin the lower the generalization error of the classifier. whereas the original problem may be stated in a finite dimensional space, it often happens that the sets to discriminate are not linearly separable in that space. for this reason, it was proposed that the original finite - dimensional space be mapped into a much higher - dimensional space, presumably making the separation easier in that space. to keep the computational load reasonable, the mappings used by svm schemes are designed to ensure that dot products may be computed easily in terms of the variables in the original space, by defining them in terms of a kernel function selected to suit the problem. the hyperplanes in the higher - dimensional space are defined as the set of points whose dot product with a vector in that space is constant. the vectors defining the hyperplanes can be chosen to be linear combinations with parameters of images of feature vectors that occur in the data base. with this choice of a hyperplane, the points in the feature space that are mapped into the hyperplane are defined by the relation :


hyperplanes can be chosen to be linear combinations with parameters of images of feature vectors that occur in the data base. with this choice of a hyperplane, the points in the feature space that are mapped into the hyperplane are defined by the relation : note that if becomes small as grows further away from, each element in the sum measures the degree of closeness of the test point to the corresponding data base point. in this way, the sum of kernels above can be used to measure the relative nearness of each test point to the data points originating in one or the other of the sets to be discriminated. note the fact that the set of points mapped into any hyperplane can be quite convoluted as a result, allowing much more complex discrimination between sets which are not convex at all in the original space. classifying data is a common task in machine learning. suppose some given data points each belong to one of two classes, and the goal is to decide which class a new data point will be in. in the case of support vector machines, a data point is viewed as a p - dimensional vector ( a list of p numbers ), and we want to know whether we can separate such points with a ( p − 1 ) - dimensional hyperplane. this is called a linear classifier. there are many hyperplanes that might classify the data. one reasonable choice as the best hyperplane is the one that represents the largest separation, or margin, between the two classes. so we choose the hyperplane so that the distance from it to the nearest data point on each side is maximized. if such a hyperplane exists, it is known as the maximum - margin hyperplane and the linear classifier it defines is known as a maximum margin classifier ; or equivalently, the perceptron of optimal stability. linear svm given some training data, a set of n points of the form where the yi is either 1 or −1, indicating the class to which the point belongs. each is a p - dimensional real vector. we want to find the maximum - margin hyperplane that divides the points having from those having. any hyperplane can be written as the set of points satisfying if the training data are linearly separable, we can select two hyperplanes in a way that they separate the data and there are no points between them, and then try to maximize their distance. the region bounded by them is called " the margin ". these hyperplanes can be described by the equations by using geometry, we find


a way that they separate the data and there are no points between them, and then try to maximize their distance. the region bounded by them is called " the margin ". these hyperplanes can be described by the equations by using geometry, we find the distance between these two hyperplanes is, so we want to minimize. as we also have to prevent data points from falling into the margin, we add the following constraint : for each either - of the first class - of the second. this can be rewritten as : we can put this together to get the optimization problem : minimize ( in ) subject to ( for any ) primal form the optimization problem presented in the preceding section is difficult to solve because it depends on | | w | |, the norm of w, which involves a square root. fortunately it is possible to alter the equation by substituting | | w | | with ( the factor of 1 / 2 being used for mathematical convenience ) without changing the solution ( the minimum of the original and the modified equation have the same w and b ). this is a quadratic programming optimization problem. more clearly : minimize ( in ) subject to ( for any ) by introducing lagrange multipliers, the previous constrained problem can be expressed as that is we look for a saddle point. in doing so all the points which can be separated as do not matter since we must set the corresponding to zero. this problem can now be solved by standard quadratic programming techniques and programs. the " stationary " karush – kuhn – tucker condition implies that the solution can be expressed as a linear combination of the training vectors only a few will be greater than zero. the corresponding are exactly the support vectors, which lie on the margin and satisfy. from this one can derive that the support vectors also satisfy which allows one to define the offset. in practice, it is more robust to average over all support vectors : dual form writing the classification rule in its unconstrained dual form reveals that the maximum margin hyperplane and therefore the classification task is only a function of the support vectors, the training data that lie on the margin. using the fact that and substituting, one can show that the dual of the svm reduces to the following optimization problem : maximize ( in ) subject to ( for any ) and to the constraint from the minimization in here the kernel is defined by. can be computed thanks to the terms : biased and unbiased hyperplanes for simplicity reasons, sometimes it is required that the hyperplane pass through the origin


any ) and to the constraint from the minimization in here the kernel is defined by. can be computed thanks to the terms : biased and unbiased hyperplanes for simplicity reasons, sometimes it is required that the hyperplane pass through the origin of the coordinate system. such hyperplanes are called unbiased, whereas general hyperplanes not necessarily passing through the origin are called biased. an unbiased hyperplane can be enforced by setting in the primal optimization problem. the corresponding dual is identical to the dual given above without the equality constraint soft margin in 1995, corinna cortes and vladimir n. vapnik suggested a modified maximum margin idea that allows for mislabeled examples. if there exists no hyperplane that can split the " yes " and " no " examples, the soft margin method will choose a hyperplane that splits the examples as cleanly as possible, while still maximizing the distance to the nearest cleanly split examples. the method introduces non - negative slack variables,, which measure the degree of misclassification of the data the objective function is then increased by a function which penalizes non - zero, and the optimization becomes a trade off between a large margin and a small error penalty. if the penalty function is linear, the optimization problem becomes : subject to ( for any ) this constraint in ( 2 ) along with the objective of minimizing can be solved using lagrange multipliers as done above. one has then to solve the following problem : dual form maximize ( in ) subject to ( for any ) the key advantage of a linear penalty function is that the slack variables vanish from the dual problem, with the constant c appearing only as an additional constraint on the lagrange multipliers. for the above formulation and its huge impact in practice, cortes and vapnik received the 2008 acm paris kanellakis award. nonlinear penalty functions have been used, particularly to reduce the effect of outliers on the classifier, but unless care is taken the problem becomes non - convex, and thus it is considerably more difficult to find a global solution. nonlinear classification the original optimal hyperplane algorithm proposed by vapnik in 1963 was a linear classifier. however, in 1992, bernhard e. boser, isabelle m. guyon and vladimir n. vapnik suggested a way to create nonlinear classifiers by applying the kernel trick ( originally proposed by aizerman et al. ) to maximum - margin hyperplanes. the resulting algorithm is formally similar, except that every dot product is


vladimir n. vapnik suggested a way to create nonlinear classifiers by applying the kernel trick ( originally proposed by aizerman et al. ) to maximum - margin hyperplanes. the resulting algorithm is formally similar, except that every dot product is replaced by a nonlinear kernel function. this allows the algorithm to fit the maximum - margin hyperplane in a transformed feature space. the transformation may be nonlinear and the transformed space high dimensional ; thus though the classifier is a hyperplane in the high - dimensional feature space, it may be nonlinear in the original input space. if the kernel used is a gaussian radial basis function, the corresponding feature space is a hilbert space of infinite dimensions. maximum margin classifiers are well regularized, so the infinite dimensions do not spoil the results. some common kernels include : - polynomial ( homogeneous ) : - polynomial ( inhomogeneous ) : - gaussian radial basis function :, for sometimes parametrized using - hyperbolic tangent :, for some ( not every ) and the kernel is related to the transform by the equation. the value w is also in the transformed space, with dot products with w for classification can again be computed by the kernel trick, i. e.. however, there does not in general exist a value w ' such that svms belong to a family of generalized linear classifiers and can be interpreted as an extension of the perceptron. they can also be considered a special case of tikhonov regularization. a special property is that they simultaneously minimize the empirical classification error and maximize the geometric margin ; hence they are also known as maximum margin classifiers. a comparison of the svm to other classifiers has been made by meyer, leisch and hornik. parameter selection the effectiveness of svm depends on the selection of kernel, the kernel ' s parameters, and soft margin parameter c. a common choice is a gaussian kernel, which has a single parameter γ. the best combination of c and γ is often selected by a grid search with exponentially growing sequences of c and γ, for example, ;. typically, each combination of parameter choices is checked using cross validation, and the parameters with best cross - validation accuracy are picked. the final model, which is used for testing and for classifying new data, is then trained on the whole training set using the selected parameters. potential drawbacks of the svm are the following three aspects : - uncalibrated class membership probabilities - the svm is only directly applicable


for classifying new data, is then trained on the whole training set using the selected parameters. potential drawbacks of the svm are the following three aspects : - uncalibrated class membership probabilities - the svm is only directly applicable for two - class tasks. therefore, algorithms that reduce the multi - class task to several binary problems have to be applied ; see the multi - class svm section. - parameters of a solved model are difficult to interpret. multiclass svm multiclass svm aims to assign labels to instances by using support vector machines, where the labels are drawn from a finite set of several elements. - building binary classifiers which distinguish between ( i ) one of the labels and the rest ( one - versus - all ) or ( ii ) between every pair of classes ( one - versus - one ). classification of new instances for the one - versus - all case is done by a winner - takes - all strategy, in which the classifier with the highest output function assigns the class ( it is important that the output functions be calibrated to produce comparable scores ). for the one - versus - one approach, classification is done by a max - wins voting strategy, in which every classifier assigns the instance to one of the two classes, then the vote for the assigned class is increased by one vote, and finally the class with the most votes determines the instance classification. - directed acyclic graph svm ( dagsvm ) - error - correcting output codes crammer and singer proposed a multiclass svm method which casts the multiclass classification problem into a single optimization problem, rather than decomposing it into multiple binary classification problems. see also lee, lin and wahba. transductive support vector machines transductive support vector machines extend svms in that they could also treat partially labeled data in semi - supervised learning by following the principles of transduction. here, in addition to the training set, the learner is also given a set of test examples to be classified. formally, a transductive support vector machine is defined by the following primal optimization problem : minimize ( in ) subject to ( for any and any ) transductive support vector machines were introduced by vladimir n. vapnik in 1998. structured svm svms have been generalized to structured svms, where the label space is structured and of possibly infinite size. a version of svm for regression was proposed in 1996 by vladimir n. vapnik, harris drucker, christopher j. c.


1995. http : / / www. springerlink. com / content / k238jx04hm87j80g / - * press, william h. ; teukolsky, saul a. ; vetterling, william t. ; flannery, b. p. ( 2007 ). " section 16. 5. support vector machines ". numerical recipes : the art of scientific computing ( 3rd ed. ). new york : cambridge university press. isbn 978 - 0 - 521 - 88068 - 8. - acm website, press release of march 17th 2009. http : / / www. acm. org / press - room / news - releases / awards - 08 - groupa - aizerman, mark a. ; braverman, emmanuel m. ; and rozonoer, lev i. ( 1964 ). " theoretical foundations of the potential function method in pattern recognition learning ". automation and remote control 25 : 821 – 837. - boser, bernhard e. ; guyon, isabelle m. ; and vapnik, vladimir n. ; a training algorithm for optimal margin classifiers. in haussler, david ( editor ) ; 5th annual acm workshop on colt, pages 144 – 152, pittsburgh, pa, 1992. acm press - meyer, david ; leisch, friedrich ; and hornik, kurt ; the support vector machine under test, neurocomputing 55 ( 1 – 2 ) : 169 – 186, 2003 http : / / dx. doi. org / 10. 1016 / s0925 - 2312 ( 03 ) 00431 - 4 - hsu, chih - wei ; chang, chih - chung ; and lin, chih - jen ( 2003 ). a practical guide to support vector classification. department of computer science and information engineering, national taiwan university. http : / / www. csie. ntu. edu. tw / ~ cjlin / papers / guide / guide. pdf. - duan, kai - bo ; and keerthi, s. sathiya ( 2005 ). " which is the best multiclass svm method? an empirical study ". proceedings of the sixth international workshop on multiple classifier systems. lecture notes in computer science 3541 : 278. doi : 10. 1007 / 11494683 _ 28. isbn 978 - 3 - 540 - 26306 - 7. - hsu, chih - wei


classifier systems. lecture notes in computer science 3541 : 278. doi : 10. 1007 / 11494683 _ 28. isbn 978 - 3 - 540 - 26306 - 7. - hsu, chih - wei ; and lin, chih - jen ( 2002 ). " a comparison of methods for multiclass support vector machines ". ieee transactions on neural networks. - platt, john ; cristianini, n. ; and shawe - taylor, j. ( 2000 ). " large margin dags for multiclass classification ". in solla, sara a. ; leen, todd k. ; and muller, klaus - robert ; eds. advances in neural information processing systems. mit press. pp. 547 – 553. - dietterich, thomas g. ; and bakiri, ghulum ; bakiri ( 1995 ). " solving multiclass learning problems via error - correcting output codes ". journal of artificial intelligence research, vol. 2 2 : 263 – 286. arxiv : cs / 9501101. bibcode : 1995cs........ 1101d. unknown parameter - crammer, koby ; and singer, yoram ( 2001 ). " on the algorithmic implementation of multiclass kernel - based vector machines ". j. of machine learning research 2 : 265 – 292. - lee, y. ; lin, y. ; and wahba, g. ( 2001 ). " multicategory support vector machines ". computing science and statistics 33. - lee, y. ; lin, y. ; and wahba, g. ( 2004 ). " multicategory support vector machines, theory, and application to the classification of microarray data and satellite radiance data ". journal of the american statistical association 99 ( 465 ) : 67 – 81. doi : 10. 1198 / 016214504000000098. - joachims, thorsten ; " transductive inference for text classification using support vector machines ", proceedings of the 1999 international conference on machine learning ( icml 1999 ), pp. 200 - 209. - drucker, harris ; burges, christopher j. c. ; kaufman, linda ; smola, alexander j. ; and vapnik, vladimir n. ( 1997 ) ; " support vector regression machines ", in advances in neural information processing systems 9, nips 1996,


, christopher j. c. ; kaufman, linda ; smola, alexander j. ; and vapnik, vladimir n. ( 1997 ) ; " support vector regression machines ", in advances in neural information processing systems 9, nips 1996, 155 – 161, mit press. - suykens, johan a. k. ; vandewalle, joos p. l. ; least squares support vector machine classifiers, neural processing letters, vol. 9, no. 3, jun. 1999, pp. 293 – 300. - ferris, michael c. ; and munson, todd s. ( 2002 ). " interior - point methods for massive support vector machines ". siam journal on optimization 13 ( 3 ) : 783 – 804. doi : 10. 1137 / s1052623400374379. - burges, christopher j. c. ; a tutorial on support vector machines for pattern recognition, data mining and knowledge discovery 2 : 121 – 167, 1998 - www. kernel - machines. org ( general information and collection of research papers ) - teknomo, k. svm tutorial using spreadsheet visual introduction to svm. - www. support - vector - machines. org ( literature, review, software, links related to support vector machines — academic site ) - videolectures. net ( svm - related video lectures ) - animation clip : svm with polynomial kernel visualization - fletcher, tristan ; a very basic svm tutorial for complete beginners - karatzoglou, alexandros et al. ; support vector machines in r, journal of statistical software april 2006, volume 15, issue 9. - shogun ( toolbox ) contains about 20 different implementations of svms, written in c + + with matlab, octave, python, r, java, lua, ruby and c # interffaces - libsvm libsvm is a library of svms which is actively patched - liblinear liblinear is a library for large linear classification including some svms - flssvm flssvm is a least squares svm implementation written in fortran - shark shark is a c + + machine learning library implementing various types of svms - dlib dlib is a c + + library for working with kernel methods and svms - svm light is a collection of software tools for learning and classification using svm. - stanford university andrew ng video on sv


various types of svms - dlib dlib is a c + + library for working with kernel methods and svms - svm light is a collection of software tools for learning and classification using svm. - stanford university andrew ng video on svm - theodoridis, sergios ; and koutroumbas, konstantinos ; " pattern recognition ", 4th edition, academic press, 2009, isbn 978 - 1 - 59749 - 272 - 0 - cristianini, nello ; and shawe - taylor, john ; an introduction to support vector machines and other kernel - based learning methods, cambridge university press, 2000. isbn 0 - 521 - 78019 - 5 ( svm book ) - huang, te - ming ; kecman, vojislav ; and kopriva, ivica ( 2006 ) ; kernel based algorithms for mining huge data sets, in supervised, semi - supervised, and unsupervised learning, springer - verlag, berlin, heidelberg, 260 pp. 96 illus., hardcover, isbn 3 - 540 - 31681 - 7 - kecman, vojislav ; learning and soft computing — support vector machines, neural networks, fuzzy logic systems, the mit press, cambridge, ma, 2001. - scholkopf, bernhard ; and smola, alexander j. ; learning with kernels, mit press, cambridge, ma, 2002. isbn 0 - 262 - 19475 - 9 - scholkopf, bernhard ; burges, christopher j. c. ; and smola, alexander j. ( editors ) ; advances in kernel methods : support vector learning, mit press, cambridge, ma, 1999. isbn 0 - 262 - 19416 - 3. - shawe - taylor, john ; and cristianini, nello ; kernel methods for pattern analysis, cambridge university press, 2004. isbn 0 - 521 - 81397 - 2 ( kernel methods book ) - steinwart, ingo ; and christmann, andreas ; support vector machines, springer - verlag, new york, 2008. isbn 978 - 0 - 387 - 77241 - 7 ( svm book ) - tan, peter jing ; and dowe, david l. ( 2004 ) ; mml inference of oblique decision trees, lecture notes in artificial intelligence ( lnai ) 3339, springer - verlag, pp1082 - 1088. ( this paper uses minimum message length ( mml ) and actually incorporates probabilistic support


##l inference of oblique decision trees, lecture notes in artificial intelligence ( lnai ) 3339, springer - verlag, pp1082 - 1088. ( this paper uses minimum message length ( mml ) and actually incorporates probabilistic support vector machines in the leaves of decision trees. ) - vapnik, vladimir n. ; the nature of statistical learning theory, springer - verlag, 1995. isbn 0 - 387 - 98780 - 0 - vapnik, vladimir n. ; and kotz, samuel ; estimation of dependences based on empirical data, springer, 2006. isbn 0 - 387 - 30865 - 2, 510 pages [ this is a reprint of vapnik ' s early book describing philosophy behind svm approach. the 2006 appendix describes recent development ]. - fradkin, dmitriy ; and muchnik, ilya ; support vector machines for classification in abello, j. ; and carmode, g. ( eds ) ; discrete methods in epidemiology, dimacs series in discrete mathematics and theoretical computer science, volume 70, pp. 13 – 20, 2006.. succinctly describes theoretical ideas behind svm. - bennett, kristin p. ; and campbell, colin ; support vector machines : hype or hallelujah?, sigkdd explorations, 2, 2, 2000, 1 – 13.. excellent introduction to svms with helpful figures. - ivanciuc, ovidiu ; applications of support vector machines in chemistry, in reviews in computational chemistry, volume 23, 2007, pp. 291 – 400. reprint available : - catanzaro, bryan ; sundaram, narayanan ; and keutzer, kurt ; fast support vector machine training and classification on graphics processors, in international conference on machine learning, 2008 - campbell, colin ; and ying, yiming ; learning with support vector machines, 2011, morgan and claypool. isbn 978 - 1 - 60845 - 616 - 1.


the troposphere is the lowest portion of earth ' s atmosphere. it contains approximately 80 % of the atmosphere ' s mass and 99 % of its water vapor and aerosols. the average depth of the troposphere is approximately 17 km ( 11 mi ) in the middle latitudes. it is deeper in the tropics, up to 20 km ( 12 mi ), and shallower near the polar regions, at 7 km ( 4. 3 mi ) in summer, and indistinct in winter. the lowest part of the troposphere, where friction with the earth ' s surface influences air flow, is the planetary boundary layer. this layer is typically a few hundred meters to 2 km ( 1. 2 mi ) deep depending on the landform and time of day. the border between the troposphere and stratosphere, called the tropopause, is a temperature inversion. the word troposphere derives from the greek : tropos for " change " reflecting the fact that turbulent mixing plays an important role in the troposphere ' s structure and behavior. most of the phenomena we associate with day - to - day weather occur in the troposphere. pressure and temperature structure the chemical composition of the troposphere is essentially uniform, with the notable exception of water vapor. the source of water vapor is at the surface through the processes of evaporation and transpiration. furthermore the temperature of the troposphere decreases with height, and saturation vapor pressure decreases strongly as temperature drops, so the amount of water vapor that can exist in the atmosphere decreases strongly with height. thus the proportion of water vapor is normally greatest near the surface and decreases with height. the pressure of the atmosphere is maximum at sea level and decreases with higher altitude. this is because the atmosphere is very nearly in hydrostatic equilibrium, so that the pressure is equal to the weight of air above a given point. the change in pressure with height, therefore can be equated to the density with this hydrostatic equation : since temperature in principle also depends on altitude, one needs a second equation to determine the pressure as a function of height, as discussed in the next section. * the temperature of the troposphere generally decreases as altitude increases. the rate at which the temperature decreases,, is called the environmental lapse rate ( elr ). the elr is nothing more than the difference in temperature between the surface and the tropopause divided by the height. the reason for this temperature difference is the absorption of the


,, is called the environmental lapse rate ( elr ). the elr is nothing more than the difference in temperature between the surface and the tropopause divided by the height. the reason for this temperature difference is the absorption of the sun ' s energy occurs at the ground which heats the lower levels of the atmosphere, and the radiation of heat occurs at the top of the atmosphere cooling the earth, this process maintaining the overall heat balance of the earth. as parcels of air in the atmosphere rise and fall, they also undergo changes in temperature for reasons described below. the rate of change of the temperature in the parcel may be less than or more than the elr. when a parcel of air rises, it expands, because the pressure is lower at higher altitudes. as the air parcel expands, it pushes on the air around it, doing work ; but generally it does not gain heat in exchange from its environment, because its thermal conductivity is low ( such a process is called adiabatic ). since the parcel does work and gains no heat, it loses energy, and so its temperature decreases. ( the reverse, of course, will be true for a sinking parcel of air. ) since the heat exchanged is related to the entropy change by, the equation governing the temperature as a function of height for a thoroughly mixed atmosphere is if the air contains water vapor, then cooling of the air can cause the water to condense, and the behavior is no longer that of an ideal gas. if the air is at the saturated vapor pressure, then the rate at which temperature drops with height is called the saturated adiabatic lapse rate. more generally, the actual rate at which the temperature drops with altitude is called the environmental lapse rate. in the troposphere, the average environmental lapse rate is a drop of about 6. 5 °c for every 1 km ( 1, 000 meters ) in increased height. the environmental lapse rate ( the actual rate at which temperature drops with height, ) is not usually equal to the adiabatic lapse rate ( or correspondingly, ). if the upper air is warmer than predicted by the adiabatic lapse rate ( ), then when a parcel of air rises and expands, it will arrive at the new height at a lower temperature than its surroundings. in this case, the air parcel is denser than its surroundings, so it sinks back to its original height, and the air is stable against being lifted. if, on the contrary, the upper air is cooler than


lower temperature than its surroundings. in this case, the air parcel is denser than its surroundings, so it sinks back to its original height, and the air is stable against being lifted. if, on the contrary, the upper air is cooler than predicted by the adiabatic lapse rate, then when the air parcel rises to its new height it will have a higher temperature and a lower density than its surroundings, and will continue to accelerate upward. temperatures decrease at middle latitudes from an average of 15°c at sea level to about - 55°c at the top of the tropopause. at the poles, the troposphere is thinner and the temperature only decreases to - 45°c, while at the equator the temperature at the top of the troposphere can reach - 75°c. the tropopause is the boundary region between the troposphere and the stratosphere. measuring the temperature change with height through the troposphere and the stratosphere identifies the location of the tropopause. in the troposphere, temperature decreases with altitude. in the stratosphere, however, the temperature remains constant for a while and then increases with altitude. the region of the atmosphere where the lapse rate changes from positive ( in the troposphere ) to negative ( in the stratosphere ), is defined as the tropopause. thus, the tropopause is an inversion layer, and there is little mixing between the two layers of the atmosphere. atmospheric flow the flow of the atmosphere generally moves in a west to east direction. this however can often become interrupted, creating a more north to south or south to north flow. these scenarios are often described in meteorology as zonal or meridional. these terms, however, tend to be used in reference to localised areas of atmosphere ( at a synoptic scale ). a fuller explanation of the flow of atmosphere around the earth as a whole can be found in the three - cell model. zonal flow a zonal flow regime is the meteorological term meaning that the general flow pattern is west to east along the earth ' s latitude lines, with weak shortwaves embedded in the flow. the use of the word " zone " refers to the flow being along the earth ' s latitudinal " zones ". this pattern can buckle and thus become a meridional flow. meridional flow when the zonal flow buckles, the atmosphere can flow in a more longitudinal ( or meridi


the earth ' s latitudinal " zones ". this pattern can buckle and thus become a meridional flow. meridional flow when the zonal flow buckles, the atmosphere can flow in a more longitudinal ( or meridional ) direction, and thus the term " meridional flow " arises. meridional flow patterns feature strong, amplified troughs and ridges, with more north - south flow in the general pattern than west - to - east flow. three - cell model the three cells model attempts to describe the actual flow of the earth ' s atmosphere as a whole. it divides the earth into the tropical ( hadley cell ), mid latitude ( ferrel cell ), and polar ( polar cell ) regions, dealing with energy flow and global circulation. its fundamental principle is that of balance - the energy that the earth absorbs from the sun each year is equal to that which it loses back into space, but this however is not a balance precisely maintained in each latitude due to the varying strength of the sun in each " cell " resulting from the tilt of the earth ' s axis in relation to its orbit. it demonstrates that a pattern emerges to mirror that of the ocean - the tropics do not continue to get warmer because the atmosphere transports warm air poleward and cold air equatorward, the effect of which appears to be that of heat and moisture distribution around the planet. synoptic scale observations and concepts forcing is a term used by meteorologists to describe the situation where a change or an event in one part of the atmosphere causes a strengthening change in another part of the atmosphere. it is usually used to describe connections between upper, middle or lower levels ( such as upper - level divergence causing lower level convergence in cyclone formation ), but can sometimes also be used to describe such connections over distance rather than height alone. in some respects, tele - connections could be considered a type of forcing. divergence and convergence an area of convergence is one in which the total mass of air is increasing with time, resulting in an increase in pressure at locations below the convergence level ( recall that atmospheric pressure is just the total weight of air above a given point ). divergence is the opposite of convergence - an area where the total mass of air is decreasing with time, resulting in falling pressure in regions below the area of divergence. where divergence is occurring in the upper atmosphere, there will be air coming in to try to balance the net loss of mass ( this is called the principle of mass conservation )


time, resulting in falling pressure in regions below the area of divergence. where divergence is occurring in the upper atmosphere, there will be air coming in to try to balance the net loss of mass ( this is called the principle of mass conservation ), and there is a resulting upward motion ( positive vertical velocity ). another way to state this is to say that regions of upper air divergence are conducive to lower level convergence, cyclone formation, and positive vertical velocity. therefore, identifying regions of upper air divergence is an important step in forecasting the formation of a surface low pressure area. - " iss022 - e - 062672 caption ". nasa. retrieved 21 september 2012. - mcgraw - hill concise encyclopedia of science & technology. ( 1984 ). troposhere. " it contains about four - fifths of the mass of the whole atmosphere. " - danielson, levin, and abrams, meteorology, mcgraw hill, 2003 - landau and lifshitz, fluid mechanics, pergamon, 1979 - landau and lifshitz, statistical physics part 1, pergamon, 1980 - kittel and kroemer, thermal physics, freeman, 1980 ; chapter 6, problem 11 - " american meteorological society glossary - zonal flow ". allen press inc. june 2000. retrieved 2006 - 10 - 03. - " american meteorological society glossary - meridional flow ". allen press inc. june 2000. retrieved 2006 - 10 - 03. - " meteorology - msn encarta, " energy flow and global circulation " ". encarta. msn. com. archived from the original on 2009 - 10 - 31. retrieved 2006 - 10 - 13. | look up troposphere in wiktionary, the free dictionary. | - composition of the atmosphere, from the university of tennessee physics dept. - chemical reactions in the atmosphere - http : / / encarta. msn. com / encyclopedia _ 761571037 _ 3 / meteorology. html # s12 ( archived 2009 - 10 - 31 )


case study is often defined in different ways, reflecting evolving practice. what is important then is to define the concept for yourself, and explain to your audience how you are using the term. - a research approach in which one or few instances of a phenomenon are studied in depth ( given, 2008 ). - an empirical inquiry that investigates a contemporary phenomenon within its real - life context ; when the boundaries between phenomenon and context are not clearly evident ; and in which multiple sources of evidence are used. ( yin, 1984 ) case study involves a detailed in depth analysis of an organisation, person, a group, an event, allowing an understanding of complex phenomena, such as organisations. a case study generally involves looking at a single case ( which already exists ), an object of study which is easily identified and separated ( a bounded system ) from other similar objects e. g. an organization, a place, an illness in one patient. case study is a useful methodology for focussing on relationships connecting everyday practices in natural settings, placing attention on a local situation ( stake, 2006 ). the case study is useful to investigate an issue in depth and ‘ provide an explanation that can cope with the complexity and subtlety of real of life situation ’ ( denscombe, 2010, p55 ). research questions revolve around ‘ how? ’ or ‘ why? ’ and may be explanatory, exploratory or descriptive in nature ( yin, 2003 ). case study can be used to develop theory. yin ( 2003, p 1 ) notes that a case study is a way to ‘ contribute to our knowledge of individual, group, organisational, social, political and related phenomena ’ case study can be used to test theory : what is it supposed to do and does it do that? case studies can be used to trace a process, developing an understanding and then test it ( bennett, andrew ) data collection case studies generally use a combination of data collection methods. multiple case studies in multiple cases, research single cases are meaningful in relation to the other cases cited. multiple case study research needs to use cases that are similar in some ways. the cases become " members of a group or examples of a phenomenon " ( stake, 2006, p. 6 ). this allows examination of what is similar and dissimilar about the cases. the researcher is looking for patterns and uniqueness, particulars and generalisations in the cases developed. references and resources denscombe, martyn ( 2010 ) ( 4th ed ). the good research guide


dissimilar about the cases. the researcher is looking for patterns and uniqueness, particulars and generalisations in the cases developed. references and resources denscombe, martyn ( 2010 ) ( 4th ed ). the good research guide for small scale social research projects. maidenhead : open university pres mcgraw hill dufour, s. & foutin, v., ‘ annotated bibliography of case study method ’, current sociology vol. 40 / 1, 1992, pp. 166 - 181. fidel, r. ( 1984 ). ‘ the case study method : a case study ’, library and information science research vol. 6 / 3, pp. 273 - 288. garson, g. d. ( 2008 ). case studies, available from http : / / faculty. chass. ncsu. edu / garson / pa765 / cases. htm gerring, j. ( 2007 ). case study research : principles and practices, cambridge university press, cambridge. gilbertson, d. w. & stone, r. j. ( 1985 ) ( 2nd ed ). human resources management : cases and readings. sydney : mcgraw - hill, 1985. giving, l. m. ( 2008 ) ( ed. ), the sage encyclopedia of qualitative research methods, los angeles : sage. hossain, dewan mahboob ( 2009 ). ' case study research ' social science research network http : / / ssrn. com / abstract = 1444863 marshall, c. & rossman, g. b. ( 2006 ) ( 4th ed ). designing qualitative research, thousand oaks : sage. merriam s. ( 1998 ). qualitative research and case study application in education. san francisco : jossey bass. ragin, c. c. & becker, h. s. ( 1992 ), what is a case? exploring the foundations of social enquiry, cambridge university press, cambridge. sadler, d. royce ( 1985 ). ‘ evaluation, policy analysis and multiple case studies : aspects of focus and sampling ’, educational evaluation and policy analysis, vol. 7 / 2, pp. 143 - 149. simons ( 2009 ). case study research in practice. london : sage stake, r. e. ( 1995 ). the art of case study research. thousand oaks : sage publications. stake, r. e. ( 2006 ), multiple case study analysis, new york & london :


research in practice. london : sage stake, r. e. ( 1995 ). the art of case study research. thousand oaks : sage publications. stake, r. e. ( 2006 ), multiple case study analysis, new york & london : the guildford press. soy, susan k. ( 1997 ). the case study as a research method. available from http : / / www. ischool. utexas. edu / ~ ssoy / usesusers / l391d1b. htm stoecker, r., ‘ evaluating and rethinking the case study ’, the sociological review vol. 39, no. 1, february 1991, pp. 88 - 112. yin, r. k. ( 1989 ). ‘ case study research design and method ’. applied social research methods series 5. newbury park : sage young, raymond ( 2010 ). case study research http : / / ise. canberra. edu. au / raymond /? s = case + study zach, l. ( 2006 ), ‘ using multiple case studies design to investigate the information - seeking behaviour of arts administrators ’, library trends vol. 55 / 1, pp. 4 - 21. see also - topic : business case studies - portal : social entrepreneurship / case studies / more - wikiversity : case studies - cislunarfreighter / scripts and case studies - case studies in patent litigation - portal : social entrepreneurship / case studies - evidence - based medicine / case studies - case study : blended design and openness - case study in psychology


- common names : northern hairy - nosed wombat, queensland hairy - nosed wombat, yaminon - scientific name : lasiorhinus krefftii - national conservation status : endangered ( likely to become extinct if threats continue ) - size : 35 cm high, 1 m long - weight : up to 35 kg ( females slightly heavier than males ) the northern hairy - nosed wombat is a marsupial with a backward facing pouch. the curious name comes from its distinctive muzzle which is covered with short brown hairs. it is strong and heavily built, with short, powerful legs and strong claws that are used to dig burrows or search for suitable plants to eat. its fur is soft, silky, and mainly brown, mottled with grey, fawn and black. it has a broad head, and the ears are long and slightly pointed with tufts of white hair on the edges. like most marsupials, the northern hairy - nosed wombat is active at night, usually at dawn or dusk. although mostly solitary, wombats often share burrows. each burrow has several entrances and contains moist air which stays at a constant temperature throughout the year. the northern hairy - nosed wombat eats native and introduced grasses and stays close to one of its many burrows. the wombat ' s teeth never stop growing, allowing it to grind its food even when old. the northern hairy - nosed wombat gives birth to one young during the wet season ( november - april ). the young stay in the mothers pouch for eight to nine months. they leave their mother at about 15 months. the northern hairy - nosed wombat once occurred near deniliquin ( new south wales ), on the moonie river near st george ( southern queensland ) and at epping forest near clermont ( central queensland ). fossil records from new south wales, victoria and queensland show that they lived over a larger area, but probably not in high numbers. the last known colony of northern hairy - nosed wombats is now restricted to 300 ha in epping forest national park in central queensland. the northern hairy - nosed wombat occurs along an ancient water course in the park where the soil is sandy and dry. their feeding areas contain native grasses, scattered eucalypts and acacias, and patches of scrub. the wombats live in groups of large burrows usually located near trees. habitat loss and change, drought and competition with cattle, sheep and rabbits for food have contributed to the decline of the northern hairy - nosed wombat. epping forest national park is


the wombats live in groups of large burrows usually located near trees. habitat loss and change, drought and competition with cattle, sheep and rabbits for food have contributed to the decline of the northern hairy - nosed wombat. epping forest national park is now fenced to keep out cattle and sheep and will be fenced during 2002 to exclude dingoes which killed 10 northern hairy - nosed wombats during 2000 - 01. introduced buffel grass, planted in the area for cattle feed, outcompetes the native grasses and forces the wombats to travel further to find the native species they prefer to eat. the small population of northern hairy - nosed wombats that remains is susceptible to predation, fire and inbreeding. epping forest national park was established in 1971 to protect the habitat of the northern hairy - nosed wombat. access into the park is restricted to researchers and park managers. the park is protected from wildfires by fire breaks and patch burning of small areas. after the removal of cattle in 1982, wombat numbers increased from 35 to about 70 in 1989. numbers remained steady during a major drought which spanned the first half of the 1990 ' s. after several good years of rainfall, the population has increased to 110. programs to control buffel grass and improve the supply of native grasses are helping the wombats to move into other suitable habitats in the park. management of epping forest national park and ongoing research on the ecology of the northern hairy - nosed wombat also contribute to the long term conservation of this species. as well, a captive breeding program on the southern hairy - nosed wombat is currently under way. if this proves successful, it is hoped the techniques developed can be applied to the captive breeding of northern hairy - nosed wombats. there are three species of wombat in australia. the northern hairy - nosed wombat is the largest. the other two are : common wombat ( vombatus ursinis ) the common wombat occurs in southeastern australia. it has coarser hair, a smaller tail and shorter, more rounded ears than the northern hairy - nosed wombat. it is nocturnal during the summer, but in winter it often comes out of its burrow during the day. common wombats breed at any time of the year. they live to 15 years in the wild, and up to 20 years in captivity. southern hairy - nosed wombat ( lasiorhinus latifrons ) this species occurs in parts of southern south australia, southeastern western australia and western victoria. it is the smallest


apple is known for supporting educational uses of its technologies. on apple learning interchange community, for instance, teachers can find news and share lesson plans and ideas on different subjects. of course, apple also supports the use of their mobile devices for learning, and here is their official website dedicated to just that : showcase different ways the iphone / ipod touch can be used to support education. “ ipod touch and iphone are perfect for on - the - go learning. but don ’ t let their small size fool you. these devices put thousands of apps and countless possibilities in your pocket. ” also noteworthy is their website showcasing educational uses of the ipad. this website highlights features and uses such as : - web - ready apps ( safari, mail, maps ) - multimedia access ( music, videos, websites ) - management apps ( calendar, notes ) - iwork for document creation / editing ( pages, keynote, numbers ) - accessibility - readiness ( screen reader built in ) - itunesu ( academic content readily available on itunes ) the ipad being somewhat cost - effective, more portable, and “ closed ” ( not allowing as much student tampering and access to inappropriate content ) can be some of the good reasons to adopt the device in educational settings. “ your school day gets more productive — and more fun — when you can page through websites, write an email, flick through photos, or watch a movie with just the touch of a finger. ”


we need another and a wiser and perhaps a more mystical concept of wild animals. remote from universal nature, and living by complicated artifice, man in civilization surveys the creatures through the glass of his knowledge and sees thereby a feather magnified and the whole image in distortion. we patronize them for their incompleteness, for their tragic fate for having taken a form so far below ourselves. and therein we err, greatly err. for the animal shall not be measured by man. in a world older and more complete than ours they move finished and complete, gifted with extensions of the senses we have lost or never attained, living by voices we shall never hear. they are not brethren, they are not underlings ; they are other nations, caught with ourselves in the net of life and time, fellow prisoners of the splendour and the travail of the earth. - henry beston, the outermost house, as cited by karsten heuer in being caribou : five months on foot with an arctic herd, p. 10 in the “ complicated artifice ” of immured, urban life, i often experience the living world of the animals, plants and minerals in the tundras, deserts, mountains, rivers, lakes, forests, caves and oceans like a ghost - appendage, like a part of me that i can ’ t shake the awareness of, though i live in a fast - moving, technologically driven human ‘ nation ’ that has severed itself from these other nations both in habitat and in consciousness. the influential philosophical writings of the ancient greeks, particularly of aristotle, conveyed down to us through innumerable refracted lenses in the post - classical tradition the notion that human beings are superior to the animal kingdom as a result of their unique possession of ‘ logos ’, or the capacity to reason. aristotle took this analogy even further, to suggest that just as domestic animals ’ benefit ’ from their domination by human beings, so do women and slaves ‘ benefit ’ by being ruled by free men. aristotle ’ s writings supplied the european and early american slave - traders and slave - owners of the 17th - 19th centuries with canonical arguments for racialized, chattel slavery. what comes of the persistent human belief in separation? our human history is littered with exemplum upon exemplum of the tragic consequences of this belief. mindfulness practices provide an antidote. they help us to reestablish connections with each other and with other nations. they help us to really feel


treating hirschsprung ' s disease requires surgery to remove the affected bowel and then join the healthy bowel segments. there are three different approaches, each with a high rate of success. the choice depends on the overall health of the child and the training and experience of the surgeon sometimes a single surgical procedure is recommended to remove the aganglionic segment, then bring the healthy bowel down into the rectum, and join it to the rectal wall : this is called a " pull - through. if an infant is too small or a child is critically ill, a temporary colostomy may be necessary prior to the pull - through. in a colostomy, the colon is brought out to the surface of the abdomen so that stool contents can be discharged into a special bag for disposal subsequent to the colostomy, the pull - through surgery can be planned. the colostomy opening can then closed at the time of the pull - through, or, in some cases, at a third operation after it is clear that the pull - through is working. for most children with hirschsprung ' s disease, there are no long - term complications after successful surgery. a significant minority of children, though, are troubled with persistent constipation ), or persistent enterocolitis personal note : being affected with this disease, and not having had the surgery due to incorrect early diagnosis, i am inspired to say that living with this problem without surgery is very difficult. you may experince humiliation due to inability to control bowel movments, severe pain when having bowel movments, and constant illness due to the inability to remove toxins from the body. please do not allow a child to grow up with this disease.


eat and be young but we ’ d like to add this simple thought : what you eat can make you old. last month we explained how age equals inflammation and why inflammation could play a role in many degenerative processes, including diabetes, arthritis, heart disease, high blood pressure and cancer. ( see the april 17 issue of the shepherd for details. ) reducing inflammation may be able to slow down the aging process. and, even more important, it ’ s something you can do every day, very simply, just by eating the right foods. here ’ s how it works : the internal ph ( level of acid ) of the body is a critical factor in producing inflammation. the body is designed to function properly when the internal environment is neutral, with the exception of the stomach ’ s acidity. when your body becomes too acidic, it tries to come into balance by retaining water and taking calcium and other minerals from your bones. over time, these processes may lead to inflammation and osteoporosis. your cells, tissues and organs may prematurely break down. and some studies have shown that tumor cells, bacteria and viruses will grow at explosive rates when placed in an acidic bath. one culprit is your diet. the typical american consumes a wide variety of food and substances that create acidity within the body, such as pharmaceutical medicine, soda, processed foods, additives and preservatives. fortunately, reducing your acidity is pretty easy. try these tips : eat fresh fruits and vegetables, preferably raw. processing foods kills the enzymes they contain when they ’ re fresh, which forces the body to use its own limited reserves to digest what you eat. plus, additives and preservatives create acidity, contributing to the aging process. consume omega - 3 fatty acids, primarily from fish oil, flaxseed or hemp oil. omega - 3 fatty acid deficiency has been called the scurvy of our time, with an estimated 90 % of americans lacking in this vital nutrient. eat the right kind of processed foods. nearly every culture in history has relied on lacto - fermentation in food processing, which keeps the food alive. traditional foods like pickles, tempeh, sauerkraut, kimchi, soy sauce and miso retain critical nutrients and help to slow down the aging process. check out your ph balance. a simple way to check your own internal environment is to purchase a simple ph strip from a health food store and begin monitoring one of the most important factors in premature


| cat neutering practices in the uk and swine flu | cats and avian flu foetus infection in cats - the dangers to cats cat rescue - helpful information from canada despite neutering being one of the most common veterinary procedures, questions remain about what constitutes best practice, and when is the ideal time to neuter. these were the focus of attention at a meeting of the cat group, held in london last september, to which representatives from the uk veterinary schools, and a number of other veterinary experts, were invited. this article presents a summary of the discussions. at the beginning of november 2009, a sick 13 - year old cat in iowa, usa was diagnosed with the h1n1 ‘ swine flu ’ influenza virus. he had become lethargic, lost his appetite and had respiratory distress and diarrhoea. he was treated with antibiotics and fluids and recovered. this is the first report that cats can become infected with the swine flu virus. it is very likely that the cat caught the virus from humans. two of the three people who lived with the cat had flu - like symptoms before the cat became ill. although h1n1 has not been confirmed as the cause of their illness, there is strong circumstantial evidence that they were the source of the infection and the virus was transmitted from them to the cat rather than the other way round, as the cat did not go outdoors. there appears to be a small risk of animals catching the current swine flu virus from humans. pigs, turkeys and pet ferrets have been diagnosed with the virus. previously cats have died from eating birds infected with the earlier avian flu h5n1 virus. however, there is no evidence yet that influenza viruses spread between cats or from cats to humans. to reduce the risk of pet cats becoming infected from people with flu, the same precautions should be taken that apply to preventing human - to - human spread of the virus. close contact with cats should be avoided, particularly face to face contact. coughs and sneezes should be contained in paper tissues which should then be discarded hygienically. hands should be washed very carefully before handling pets. cats in households in which people have symptoms of flu should be monitored carefully. if cats show signs of illness, owners should seek advice immediately from their veterinary surgeon. further information, visit the websites below : protection agency http : / / www. hpa. org. uk for the environment, food and rural affairshttp : / / www


signs of illness, owners should seek advice immediately from their veterinary surgeon. further information, visit the websites below : protection agency http : / / www. hpa. org. uk for the environment, food and rural affairshttp : / / www. defra. gov. uk have been identified as one of the species which can become infected with the h5n1 avian flu virus. natural infection almost certainly occurs when cats eat infected birds, and fatal infections in cats have been recorded in germany and austria. in laboratory studies cats have been infected experimentally and have transmitted the virus to other cats with which they were in contact. recent research, the results of which have yet to be confirmed, indicates that in parts of south - east asia, where poultry have been infected with the virus, up to 20 per cent of cats have antibodies, suggesting that many more cats become infected than become ill. this raises the concern that cats might be a vehicle in which the virus can become more addapted to mammals, and therefore spread readily to man. however, there has been no evidence to date that cats have been responsible for transmitting the virus to humans. the simple and most effective way of avoiding cats being infected is to keep them indoors, especially if they are known to wander and are in an area where infected birds are known to be present. when cases of h5n! infection occur in poultry in the uk, owners within the 3 km protection zone should consider keeping their cats indoors as recommended by defra : a precautionary approach we recommend that if you live within 3km of a premises where avian influenza is confirmed ( the protection zone ) pet owners should aim to keep their cats indoors and exercise their dogs on a lead. this is for the protection of your animals and is not for public health purposes. in all other areas you should continue as normal and your pets are not at risk. ' here for defra ' s advice on avian flu and cats a recent report form the european commission standing committee on the food chain and animal health says : knowledge indicates that no h5n1 infection has ever occurred in humans due to animals other than domestic poultry. current knowledge suggests that the disease in carnivores such as cats is a “ cul de sac ” of the infection that has not lead to an increase in the risk posed by this virus for animal or public health. areas where h5n1 has been confirmed in wild birds : - sick or dead cats and dogs that may have had contacts with infected birds or their


that has not lead to an increase in the risk posed by this virus for animal or public health. areas where h5n1 has been confirmed in wild birds : - sick or dead cats and dogs that may have had contacts with infected birds or their carcasses should undergo veterinary inspection or post - mortem examination. when felt necessary by the veterinarian and in accordance with the instructions given by the veterinary authorities, further testing should be carried out ; - contacts between domestic carnivores, particularly cats, and wild birds should be prevented, i. e. cats should be kept indoors and dogs should be kept on a leash or otherwise restrained, and kept under control by the owner ; - where stray cats or dogs are found dead they should not be touched and the veterinary authorities should be informed, so that post - mortem examination and further testing can be performed ' cat group urges pet owners not to panic and abandon or rehome their cats because of fears of infection with bird flu. this highly pathogenic virus first appeared in chickens in hong kong in 1997 and spread to people, with six deaths being recorded. in 2003 there were two further human deaths associated with infection by the same subtype of virus in southern china. throughout 2004, h5n1 viruses spread throughout southeast asia resulting in the deaths, or slaughter of millions of chickens and over 30 people. to date, 167 human cases have been reported. the human infections were acquired directly from infected birds and fortunately the virus does not appear to spread between people. however, a major threat from this new virus is that suddenly it might change and cause epidemics in people. this might occur if the virus mutated in chickens or recombined with existing human influenza viruses already in people or pigs, to produce novel viruses that could then spread readily from person to person, causing widespread disease. the world health organisation is closely monitoring the situation for the appearance of any such variant viruses in people. other concerns are that the h5n1 virus has been found to cause fatal disease in domestic cats, as well as in tigers and leopards in captivity, through the consumption of infected poultry meat ; and the virus can spread between cats. therefore there is a theoretical possibility that cats may be involved in natural history of these viruses, serving as a vehicle for the spread of the virus to other species, particularly man. most authorities consider this outcome to be unlikely since previously reported disease in cats caused by avian influenza viruses have not been associated with widespread infection, or fatalities in cats. the first recorded natural


for the spread of the virus to other species, particularly man. most authorities consider this outcome to be unlikely since previously reported disease in cats caused by avian influenza viruses have not been associated with widespread infection, or fatalities in cats. the first recorded natural, fatal infection of cats with an avian influenza virus was in korea in 1942, but the subtype of that virus is not known. since then there have been anecdotal accounts of natural feline infections in thailand in 2004 and the transmission of a current h5n1 isolate from chickens to cats, and between cats, has been reported recently. it is considered even more unlikely that cats could act as a ‘ mixing vessel ' to generate recombinant influenza viruses, as might occur in people or pigs. therefore, the risk that cats might pose should be kept in perspective. kuiken t, et al ( 2004 ) avian h5n1 influenza in cats. science 306 : 241 keawcharoen j, et al ( 2004 ) avian influenza h5n1 in tigers and leopards. emerging infectious diseases 10, 2189 - 2191 cats bring avian flu into a household? we have two indoor - outdoor cats which occasionally catch rats or birds and, of course, bring them into the house. it doesn ' t take much to imagine one ' s cat catching and bringing into the house an infected, ill migratory bird. how concerned should pet owners be? and what is a reasonable course of action under such circumstances? advice from an eminent virologist and supported by defra, the british government department for the environment, food and rural affairs are that cats are susceptible to the current h5n1 strains of avian flu virus, as are garden birds. consequently, there is a theoretical risk that cats could introduce the virus into a household through predation, and that people could be infected from the bird, or the cat. the risk must be considered remote. however, in areas where bird flu has been identified it is recommended that cats are kept indoors for their own protection. also see defra ' s guidance on the handling and disposing of dead garden and wild birds websites are also a useful source of information : board on cat diseases ( abcd ) veterinary association ( bva ) society for the protection of birds ( rspb ) tritrichomonas foetus is a microscopic single - celled flagellated protozoan parasite that has traditionally been identified as a cause of reproductive disease in cattle ( infertility, abortion


for the protection of birds ( rspb ) tritrichomonas foetus is a microscopic single - celled flagellated protozoan parasite that has traditionally been identified as a cause of reproductive disease in cattle ( infertility, abortion and endometritis ). it has been found all over the world, but the widespread use of artificial insemination in breeding cattle has led to the virtual elimination of this organism from the cattle population in many countries including the uk and much of europe. there have been a number of recent studies, mostly form the usa, that have demonstrated that t foetus may also be an important cause of diarrhoea in cats. it can infect and colonises the large intestine, and can cause prolonged and intractable diarrhoea. studies have shown that this parasite mainly causes colitis ( large bowel diarrhoea ) with increased frequency of defaecation, semi - formed to liquid faeces, and sometimes fresh blood or mucus in the faeces. with severe diarrhoea the anus may become inflamed and painful, and in some cases the cats may develop faecal incontinence. although cats of all ages can be affected with diarrhoea, it is most commonly seen in young cats and kittens, the majority being under 12 months of age. most of the affected cats have come from rescue shelters and pedigree breeding colonies. abdominal ultrasound examination may show corrugation of the large bowel and local lymphadenopathy. colonic biopsies from affected cats typically show mild to severe inflammatory changes with infiltration of lymphocytes and plasma cells – a pattern commonly seen with other infectious agents and with inflammatory bowel disease. however, the parasites may be seen in close association with the mucosa. although the diarrhoea may be persistent and severe, most affected cats are otherwise well, and show no significant weight loss. infection is most commonly seen in colonies of cats and multicat households, where the organism is presumably spread between cats by close and direct contact. there has been no evidence of spread from other species, or spread via food or water. in one study, 31 % of cats at a cat show in the usa were identified as being infected with this organism, suggesting that this may be an important, common, and previously unrecognised cause of diarrhoea in cats. although most information on t foetus infection has come from studies of cats in


were identified as being infected with this organism, suggesting that this may be an important, common, and previously unrecognised cause of diarrhoea in cats. although most information on t foetus infection has come from studies of cats in the usa, we have identified several cases of infection in cats in the uk ( mostly in young pedigree cats, and all from multicat households generally with more than one cat being affected ), and it has also been identified in cats from germany, italy, spain and norway. in the uk, up to 30 % of faecal samples from cats with diarrhoea are currently being found to be infected ; with young pedigree cats ( particularly siamese and bengal ) being significantly more likely to be infected. the evidence therefore suggests that t foetus is probably quite widespread in cat populations, and infection is most likely where there is a high density of cats sharing the same environment. while t foetus is known to be a significant cause of reproductive disease in cattle ( infertility, abortion and endometritis ), its role in causing reproductive disease in cats is still unclear. there is one report of a cat from norway that came from a t foetus - infected household and developed pyometra ( which was found to contain t foetus organisms ). the cat may have been predisposed to the infection by having received six weeks of oral contraceptive ( medroxyprogesterone acetate ). it has also been suggested that tom cats may be able to harbour the infection in their prepuce. assessment of the cats faeces for the presence of t foetus can be made using a number of different methods ( see below for more details ) ; ( i ) looking for moving parasites in fresh faecal smears ( ii ) using a specific culture system or ( iii ) by detection of t foetus dna using pcr. the different methods have differing sensitivities : in one study direct smears were positive in 5 / 36 cases, culture in 20 / 36, and pcr in 34 / 36 cases ; so the pcr is by far the most sensitive test, but even this can be hampered by intermitted shedding of the parasite. diagnosis of t foetus infection is usually straightforward. the organism exists in the intestine as small, motile trophozoites, and these can be detected under the microscope. for optimum results, fresh faeces should be examined, and if any mucus has been passed with the


the organism exists in the intestine as small, motile trophozoites, and these can be detected under the microscope. for optimum results, fresh faeces should be examined, and if any mucus has been passed with the faeces this is the most likely place to find the organisms. smears of faeces / mucus diluted with some saline can be made on a microscope slide. a cover slip can be pressed over the smear and then the slide can be examined under x200 and x400 magnification. in most clinically affected cats, large numbers of the small motile organisms can be seen – they appear a little bit like microscopic tadpoles with very short tails (! ), and have an undulating membrane that runs over the length of the body. their movement is described as ‘ jerky, forward motion ’. examination of multiple smears and multiple faecal samples will improve the detection of the organism. rectal swabs can also be examined for the organism – a cotton swab can be inserted into the anus and rotated over the colonic mucosa – this is then withdrawn and a smear made on a microscope slide which is again diluted with saline and examined as above. the organism needs to be distinguished from giardia, another protozoan parasite, but with giardia infection the trophozoites tend to be far fewer in number, they are binucleate with a concave ventral ‘ sucker ’, and do not exhibit the same forward motion as t foetus. if a cat has received recent antibiotic therapy, this can suppress the number of t foetus trophozoites shed, and can make the diagnosis more difficult. in such cases, more sensitive diagnostic techniques may be preferable. two other diagnostic tests are available which are both more sensitive and specific for this organism. firstly, the organism can be cultured from faecal samples using a system developed for diagnosis in cattle. the ‘ in pouchtm tf ’ test ( biomed diagnostics, oregon, usa ) uses a liquid culture system in a sterile plastic pouch. the pouch can be inoculated with 0. 05g of faeces ( about half the size of a small pea ). the pouches are incubated at room temperature and can be examined microscopically for the motile organisms every two days for 12 days. this test is more sensitive than direct examination of faeces and helpful for detecting infections where direct smears are negative. giardi