Genus Clupea

Fishes of genus Clupea, which are classified as C. pallasi (Pacific herring) or C. harengus (Atlantic herring), are basal marine teleosts known for their less stringent requirements to reproduce. Members of C. pallasi are commonly found along the eastern coast of Bering Sea and northeast Pacific ocean (Williams and Quinn, 2000). This has lead to a variety of populations living at different conditions. Variations in living conditions among their habitats eventually lead to differences in migration cycles, age structure, growth rate, and age of maturation among populations (Semenova, et al., 2009). Because of its market value, it has been a subject of many researches originally focused on describing their adaptation mechanisms and finding means to manage their population. These initial efforts resulted to a well-defined wide range of spawning season and specific spawning locations. Gradually, studies using members of Clupea as animal model have lead to researches about epigenetics and development, physiology, and evolution (Geffen, 2009).

Role of molecular biology in ecology

Study of molecular biology of Clupea, or other animal groups, is important in population maintenance. Since its conceptualization, the use of molecular markers has gradually overtaken the role of morphology in assessing differences among populations, because morphological traits overlap between populations. For example, Atlantic and Pacific herring were differentiated based on the number of vertebrates. The multivertebrate Atlantic herring has, on an average, 57 vertebrae, while the oligovertebrate Pacific herring has 53. However, this character proves to be unreliable in population studies because the ranges of the number of vertebrates in Atlantic and Pacific herrings considerably overlap: 51-60 vertebrae for Atlantic herrings and 47-57 vertebrae for Pacific herrings (Semenova, et al., 2009).

Landscape genetics

Inferring specific environmental factors that may have caused the persisting genetic structures and their differences among populations, or predicting future genetic structures of populations based on current environmental pressures can be done through landscape genetics (Jorgensen, et al., 2005). Landscape genetics works on the presumption that genetic drift, is a reflection of habitat reduction and fragmentation, because such conditions hamper the continuity of flow of adaptive genes (Jorgensen, et al., 2005). Genetic drift is a natural evolutionary process in which a population’s allele frequencies change. The effects of genetic drift are much more magnified when the population size becomes drastically reduced. The resulting population may not represent the original population’s gene pool, may overrepresent alleles, and may subsequently not contain in them other alleles (Campbell and Reece, 2002). So how can a sudden reduction in population size and subsequent reduction in genetic monotony be prevented? By allowing migration to seek refuge and/or subsequent interpopulation interactions to allow adaptive genes to be passed on. Indeed, the genetic make-up among populations reflects the interplay of genetic drift and gene flow (Jorgensen, et al., 2005). The set of genes that allows evolutionary success changes from time to time, depending on the present environmental conditions. The variety in one’s genetic structure increases the possibility that it contains the genes encoding for proteins or mRNA that allow survival in the persisting conditions. In fishes, genetic differentiation among populations of the same species can be expected if they have (1) large spawning population sizes without considerable genetic drift, (2) freedom to migrate, (3) highly dispersive migratory life stages to increase the gene flow (Jorgensen, et al., 2005). On the contrary, isolated populations tend to reduce their genetic variability and their ability to adapt to environmental changes because they are not exposed to other populations that may have a genetic make-up different from theirs. Thus, adaptive genes, and an increased possibility of having them, are important factors ensuring survival because it allows resilience against disturbances (Piorski et al., 2008).

Genetics are also important in establishing intraspecific variations within a species, which are usually designated by morphological similarities or interbreeding ability. For such purposes, use of molecular markers is inevitable because members of a species usually look the same in terms of their morphological character (Chinain and Germain, 1997).

Molecular markers for landscape genetics

In determining genetic variations among populations of Clupea, lactate dehydrogenase (LDH) -1* and LDH-2* are two of the four polymorphous loci determined to be most informative. For example, C. harengus and C. pallasi can be differentiated just by LDH loci. Using LDH-1* locus, LDH-1* 100 allele can only be found in C. harengus, while LDH-1* 200 is only found in C. pallasi (Semenova, et al., 2009).

Just like any other scientific techniques, use of genetic markers has its drawbacks. First, compared to proteins, DNA are much harder to extract. The genetic material, especially of eukaryotes, is packed tightly with histones to fit into the nucleus. On the other hand, enzymes, such as LDH, for example, are just in the cytoplasm. In addition, the ratio of gene: protein in any cell is definitely much lower than its reciprocal. You can thus get lower amounts of gene than protein from a certain volume of tissue homogenate. Second, the DNA sequence should have already been more or less established. This is necessary in producing primers, which attach to the DNA at its complementary site. Primers will then allow selective DNA replication through PCR, or to present substrates for nucleases to cleave desired potions of the DNA. Because of these, other molecular markers have already been explored for use in population genetics.

Isoenzymatic markers

Aside from genetic markers, one of the molecular makers through which fish population is studied is through isoenzymatic markers because members of the same species can be different biochemically (Chinain and Germain, 1997). In addition, differences in proteins are reflection of differences in genes encoding them. Isoenzymes are molecular modifications of an enzyme resulting from the presence of multiple genes coding for the enzyme. This multiple genes are a result of substitution and insertion/deletion mutations in the DNA (Piorski et al., 2008).

Lactate dehydrogenase (LDH): function and structure

LDH is a NAD-dependent tetramer protein responsible for lactic acid fermentation, regulating pyruvate and lactate interconversions through redox reactions during hyper- and hypoxic conditions (Gronczewska, et al., 2003; Meany, 2007). After glycolysis, pyruvate is processed depending on the availability of oxygen. Table 1 summarizes the metabolic pathways at different oxygen concentrations. At physiological oxygen levels, pyruvate enter the mitochondria continues into Krebs cycle, after which energy is processed through an electron transport chain that utilizes oxygen in one of its steps. At hypoxic conditions, pyruvate cannot enter the Krebs cycle. Energy production is thus depended solely on glycolysis, when glucose is converted into pyruvate. What happens next is that LDH, with reducing agent as NADH, reduces pyruvate to lactate. It is not an energy-producing process, but this is necessary to continue reproducing NAD+ that is involved in glycolysis. Accumulation of lactate is harmful, as can be attested by the muscle pain humans feel after prolonged exercise that utilized lactic acid fermentation, because it can be converted to lactic acid, which affects physiological pH and causes lactic acidosis. In addition, aerobic respiration is much more efficient than glycolysis paired with lactic acid fermentation. Thus, when normal oxygen levels are restored, LDH catalyzes the oxidation of lactate by NAD+ to make pyruvate available again for metabolism (Campbell and Reece, 2002; Meany; 2007 Zietara, et al., 2009).

LDH in Clupea

LDH exists in different anatomical structures of Clupea. In spermatozoa, its main role is to reoxidize NADH and to subsequently speed up glycolysis. Lactate metabolism and NADH reoxidation will then power sperm motility even at low levels of oxygen (Gronczewska, et al., 2003). In Clupea harengus, LDH is present in skeletal muscle, cardiac muscle, and semen. The enzyme’s three isoforms have been identified as B4, A2B2, and A4. Cardiomyocytes contain all three isoforms (Gronczewska, et al., 2003), while in their spermatozoa, only B4 and A2B2 LDH isoforms can be isolated, although not as much as found in the heart. (Zietara, et al., 2009; Gronczewska, et al., 2003). The skeletal muscle has the least varied LDH, with A4 as the only type of LDH found in this tissue. It may be inferred that A4 is specific for myocytes, although it is not the main LDH isoform in cardiac muscles (Figure 1).

Isoenzyme electrophoresis

Isozyme electrophoresis is a useful technique in establishing population variations. This was first used in diatoms, and soon after applied on macroalgae, dinoflagellates (Chinain and Germain, 1997). Two electrophoresis techniques are used for the study of LDH. To screen for the presence of LDH in tissue homogenates, horizontal starch gel electrophoresis is performed. Zietara and Skorkowsi (1993) has identified 14% starch gel ran at 27 mA for 4 hours as the optimal conditions at which LDH electrophoresis should be performed. An LDH-specific stain composed of 30 mM Na-lactate, 0.25 mM NAD+, 0.1 mg/ml p-nitro blue tetrazolium chloride and 0.1 mg/ml phenasine methosulfate in 0.1 M Tris-HCl buffer, pH 8.0 is being used to incubate the gel. Once purified, the LDH-containing sample is run through polyacrylamide gel electrophoresis, and the gel is stained with Coomassie Brilliant Blue R-250 to determine its amount and to confirm differences among samples, if present, that were initially observed during starch gel electrophoresis (Gronczewska, et al., 2003).

It is the aim of this study to determine and elucidate differences among herring populations in terms of (1) LDH isoforms and (2) how their LDH respond to changes in temperature. Most studies and findings have been elucidating the effects of temperature on metabolism. Because the maximum amount of dissolved oxygen depends on how hot or how cold the water is, water temperature is a telling factor whether or not metabolism undergoes an aerobic route. When water temperature is high, water molecules have higher kinetic energy. This subsequently lessens the amount of intermolecular spaces which oxygen molecules can fill. When conditions are changed from normoxic to hypoxic conditions, it was found that metabolism gears toward the production of lactate at a much faster rate when the temperature is at 20°C, than when it is at 5°C. In addition, fishes at 20°C seem to be much more responsive to lowering oxygen levels than at the lower temperature (Li, 2008). Although these changes in metabolism may be traced to changes in LDH, it is possible that other factors contributed to increased lactate production at high temperatures and hypoxic conditions. For example, the fish, as one of its mechanisms, has undergone decreased activity to conserve energy and prevent unnecessary ATP production through lactic acid fermentation. It is thus interesting to find out whether or not changes in LDH really lead to changes in metabolic activity among populations of herring.

References

Campbell, NA and Reece, JB 2002, Biology, Fourth edition, Benjamin Cummings, San Francisco.

Chinain, M and Germain, M 1997, ‘Intraspecific variation in the dinoflagellate Gambierdiscus toxicus (Dinophyceae). I. Isozyme analysis’  Journal of Phycology, 33, 36-43.

Geffen, AJ 2009, ‘Advances in herring biology: from simple to complex, coping with plasticity and adaptability’ ICES Journal of Marine Science, 66, 1-8.

Gronczewska, J, Zietara, MS, Biegniewska, A, and Skorkowski, EF 2003, ‘Enzyme activities in fish spermatozoa with focus on lactate dehydrogenase isoenzymes from herring Clupea harengus‘ Comparative Biochemistry and Physiology, 134B, 399-406.

Gronczewska, J, Biegniewska, A, Zietara, MS, and Skorkowski, EF 2004, ‘Inhibition by tributyltin of herring skeletal muscle lactate dehydrogenase activity’ Comparative Biochemistry and Physiology, 137C, 307-311.

Jorgensen, HBH, Hansen, MM, Bekkevold, D, Ruzzante, DE, and Loeschcke, V 2005, ‘Marine landscapes and population genetic structure of herring (Clupea harengus L.) in the Baltic Sea’ unpublished

Li, VB 2008, ‘Physiological and behavioural responses of Largemouth Bass yearlings (Micropterus salmoides) to hypoxia at summer and winter temperatures,’ MSc. Thesis, Queen’s University

Meany, JE 2007, ‘Lactate dehydrogenase catalysis: Roles of keto, hydrated, and enol pyruvate’ Journal of Chemical Education, 84(9), 1520-1523.

Piorski, NM, Sanches, A, Carvalho-Costa, LF, Hatanaka, T, Carrillo-Avila, M, Freitas, PD, and Galetti Jr., PM 2008, ‘Contribution of conservation genetics in assessing neotropical freshwater fish diversity’ Brazilian Journal of Biology, 68(4, suppl.), 1039-1050.

Semenova, AV, Andreeva, AP, Karpov, AK, and Novikov, GG 2009, ‘An analysis of allozyme variation in Herring Clupea pallasi from the White and Barents Seas’ Journal of Ichthyology, 49(4), 313-330.

Williams, EH and Quinn II, TJ 2000, ‘Pacific herring, Clupea pallasi, recruitment in the Bering Sea and northeast Pacific ocean, II: relationships to environmental variables and implications to forecasting’ Fisheries Oceanpgraphy, 9(4), 300-315.

Zietara, MS, Biegniewska, A, Rurangwa, E, Scwierczynski, J, Ollevier, F, and Skorkowski, EF 2009, ‘Bioenergetics of fish spermatozoa during seme storage’ Fish Physiol Biochem, 35, 607-614.

The basic reason behind William Shakespeare starting to write Tragedy stories is due to the reason that he felt that the various other tragic plots that were being used by other English writers of his time lacked imaginative foundation and composition. The most important focus of all of Shakespeare’s tragedies was the fall of a prominent person of his story. Additional attractions of his plays used to be Suspense and climax. His effort was amazing as it was not of the customary for the time of his existence. Anybody with just very little knowledge about the writings of Shakespeare would be familiar with one of the tragedies as a Shakespearean work.

The four most outstanding and renowned tragedies that were written by William Shakespeare are King Lear, Hamlet, Othello, and Macbeth.  The word ‘tragedy’ and its derivation are considered to be uncertain even today. “The word has been said to be derived from two Greek words – tragos (goat) and oide (song) (RSC – Royal Shakespeare Company). ” All of the tragic works written by William Shakespeare have a upsetting primary actor, or ‘protagonist’ who is in due course put into a absurdity or incompatible situation that is likely to be solved by the same character –  the hero.  A mixture of bad luck and misjudgment in due course results in the bereavement of the hero of the play.

Othello – as already mentioned above is one of the four outstanding tragic works of William Shakespeare that was written by him in the year 1602.  This famous tragedy of Shakespeare predominantly focuses on the death of Othello, the protagonist and all other important characters of the play as a result of jealousy.  All of the actions of the characters of the play are motivated by this single aspect of jealousy and hence the same is very prominent in the play.  Iago and Othello are the two main characters that portray Jealousy in the play Othello.  Jealousy is the one that completely corrupts Iago and consequently makes him to display his actuality.  This in turn causes Othello to go through an utter transformation in his own self and thereby leads to the destruction of all of his friends’ lives.

It has been said that catastrophe decontaminates the fondness and warmth by panic and sympathy. That is, it replaces imaginary compassion for sheer egoism and self-centeredness. It offers a soaring and enduring interest, beyond one’s self, in kindness as such. Tragedy is believed to raise the immense, the inaccessible and the potential to fairness with the genuine, the modest and the proximity.  Tragedy is also believed to suppress and mitigate the perseverance of the will power of a man.  Even though Iago has a repute of being “full of love and honesty” (III, iii, 138), he is the one who is accountable for obliterating many lives and is viewed as an individual who “perhaps one of the most villainous characters in all literature” (Godfrey).  Iago’s jealous is pretty evident as early as in the start of the play itself.  Specifically, in Act I of the play, Iago sets the tenor for the irrational effect jealously has on the characters of the play. Although Iago is not very sure that Othello is culpable of cuckolding him, his distrust “Will do as if for surety (1.3.371)” (Curtis).  It is, nevertheless, Othello’s intense jealous behavior that encompasses a central theme of the play. Othello is center of supremacy, and his behavior and implement of free will has the most insightful effect on everybody. Iago, who is considered as the master manipulator, uses Othello’s authoritative diffidence and jealousy as a means to instantaneously change Othello’s discernment of Desdemona.

Othello- an outstanding tragic piece of William Shakespeare is one of a kind tragedy that enlivens one’s compassion and consideration in astonishing manner.  The ethical aspects that Othello conveys have a closer relevance to the apprehensions of human life than that of any other works written by Shakespeare. If the other tragedies of Shakespeare are observed, each one of them portrays and conveys different aspects of morality.  The themes in King Lear and Macbeth contrast in the way that the pathos as portrayed in the play Lear are more dominant and are actually not so natural, however, they lack the consideration and compassion as observed in Macbeth.  In the same way Hamlet is more secluded and impulse.  In the same way, if Othello is observed it is more thoughtful, philosophical and heartwarming.

Interestingly, the term ‘Jealous’ apparently is appeared for about 21 times in the entire play of Othello.  Specifically, it becomes a common term that is used in the dialogues of Othello, Desdemona, Iago, Casio and Emilia.  Furthermore, Emilia and Iago are the two characters who have a pivotal role in this tragic play and they seemed to have apparently used the term of ‘jealousy’ almost seven times individually.   All through the play, Othello has been portrayed as an extremely strong character and he seems to be very proud of every single action of him. The control is not only of authority but of the sagacity of him being an excellent soldier.  In Act I, Othello has a brawl with Brabantio, who actually comes to kill him, but even before he attempts to attack Othello, Othello said, “Hold your hands, both of you of my inclining and the rest.  Were it my cue to fight, I should have known it without a prompter” (I, ii, lines 80-3) (Field of Themes).” The power displayed in this scene by Othello is quite amazing.

The crucial struggle that the character of Othello faces in the play is trying to recognize the truth to believe in. Othello’s own self sympathy and qualms of others allows Iago to even make Othello rethink and doubt the truth told by his wife. “This struggle within himself shows the weakness of Othello. It shows how his own doubts and questions of how is view allowed for evil and deception to easily overrun his mind. The actor must understand that this is not because Othello is slow or easily influenced, but rather partly worn and broken by his isolation from his own town. Iago is able to awaken these feelings of rejection and confusion that feed the feelings of evil and betrayal. By this it is how Othello grows able to murder his own wife. His mind is clouded and overwhelmed with years of feelings building up until the seal is broken by a wise and malevolent plot (Ross).”

The power and command over any situation that Othello has is one his strongest distinctiveness.  All through the entire first act, it can be observed that Othello is portrayed as a man with extensive power and an innate leadership. However, it would be difficult for anybody to believe such a man change all of a sudden (Field of Themes).  This change in Othello is evident from the scene when Lodovico notices Othello hitting Desdemona. As already mentioned above, the most significant of all the various themes of this play are the risks of love transforming into jealousy and the consequences of one getting his revenge.  The results of these themes are that a man trusts another man rather than his own wife, and that four persons are killed and two marriages damaged totally.  This play clearly portrays how letting emotion rule the body and mind instead of rational thought doing the same can eventually result in destruction. While most of the people may not believe that their individual actions can have such massive repercussions, as rightly said, the path to hell is paved with noble intentions. “Shakespeare intends to warn people of the dangers of acting without thought; to bring people aware of who is around them and what ulterior motives they may have when you take their counsel; and to show that every small move you make impacts the world around you to no end (Griffin).”

Othello continued to be very famous right through the 18th and 19th centuries, and numerous of the most radiant actors of that time sought after the role of the Moor, as Othello was called by many Venetians.  Othello, undoubtedly, is a most famous and one of the best tragedies written by Shakespeare. It is actually about love that transforms to be bad as a result of jealousy.  Shakespeare builds an influential drama of a marriage that originates with attraction amid the unusual Moor Othello and a fair Venetian lady named Desdemona, with elopement, and with strong mutual loyalty and that eventually ends impulsively with jealousy, anger and brutal deaths.

Works Cited

Curtis, Jerry. Jealousy: A Major Theme of Shakespeare’s ‘Othello’. 2009. 14 December 2009 <http://www.helium.com/items/100575-jealousy-a-major-theme-in-shakespeares-othello>.

Field of Themes. Character Analysis. 02 November 2009 <http://www.field-of-themes.com/shakespeare/essays/Eothello3.htm>.

Godfrey, D. R. Analysis of Shakespeare’s Othello. n.d.

Griffin, Alice. Themes in Shakespeare’s Othello. 03 July 2009. 14 December 2009 <http://www.associatedcontent.com/article/1902208/themes_in_shakespeares_othello.html>.

Ross, Jake. Analysis of Othello. 2009. 02 November 2009 <http://ezinearticles.com/?Analysis-of-Othello&id=148684>.

RSC – Royal Shakespeare Company. Macbeth. 02 June 2009 <http://www.rsc.org.uk/macbeth/tragedy/tragedies.html>.

Some of the common eating disorders in women are anorexia nervosa and bulimia nervosa. There are theories that have been put across to clarify the development of these disorders. One of the theories is that of childhood sex abuse the relationship between sexual abuse and the development of eating disorders has been an area of attention in the last couple of years. Researchers have tried to make a clarification of this potential connection using a wide range of population samples and research methods. The results of these methods have also varied and almost inconclusive. Many research designs have been functionally applied by different researchers but the results of their research have been dogged by methodology problems.  This paper will look at some of the research designs that have been used to try to explain the connection between these two variables.

The relationship between sexual abuse and the development of eating disorders has been an area of attention in the last couple of years. Researchers have tried to make a clarification of this potential connection using a wide range of population samples and research methods (Finkelor, 1979). The results of these methods have also varied and almost inconclusive. Many research designs have been applied by different researchers but the results of their research have been dogged by methodology problems. In most cases, women who were sexually abused when they were young tend to have emotional problems and they tend to exhibit some behaviors that are aimed at fighting back at the perpetrator of the act or as a way of managing the problem. This research is very important because it can help in the psychological treatment of the eating disorders using the cognitive behavioral therapy method, should it be conclusively established that there is an overt relationship between the eating disorders and childhood sexual abuse. This is because cognitive behavioral therapy is the best method of treating any cognitive behavior that may be exhibited in a human being. But is it is not conclusively found out that there is a relationship between childhood sex abuse and eating disorders like bulimia nervosa and anorexia nervosa, then application of cognitive behavioral therapy to treat the eating disorders may be misguided. In the literature review below the complicated connection between sexual abuse and eating disorders will be examined at the same time discussing the methodological defects of the various research designs used. The paper will end with a conclusive critique of the whole research exercise and give a way forward.

Review of Literature

Anorexic Samples

Steiger and Zanko compared the levels of incestuous abuses and extra familiar abuses among women with eating disorders who met the DSMR-111 criteria, women with psychiatric disorders and normal women (Garner & Garfinkel, 2009). The researchers were interested in the psychological effects of maltreatment and this interest led them to examine psychological defenses which are known to filter effects and perceptions. These differences were vital to the researchers because victims of incest usually have maladaptive defenses which have a self victimizing quality where if they angry with others, the resort to act that are self sabotaging. Secondly women with eating disorders usually use defenses that are primitive as compared to psychiatrically disturbed ones or the normal ones. This study was designed in order to make a determination of how traumas like sex based abuse might have effects on the development of the defense styles. So as to compare the rates between the disorders subtypes the women were divided into various groups. These groups are the anorexic restricters, anorexic bingers, bulimic anorexics and bulimics without anorexia. To make this comparison a group of 20 women was formed within the age range of 18-25. There was a normal control group of 24 women from diverse backgrounds who were of the same age range with the women who had eating disorders. A defense style questionnaire was used to make an assessment of the defense styles and in order to make a study of the sexual schemata, a self report questionnaire was used where the respondents indicated the following information about their sexual abuse during their childhood and adolescence: The perpetrator, the victim, frequency of the sexual abuse, the nature of the sexual abuse and the age at which the sexual abuse took place. The researchers also administered an eating attitudes test in order to establish the existence of eating disorders amongst the subjects used as a control (Garner et al, 1983). The researchers noted that 30 percent of the women with eating disorders reported sexual abuse, however; this trauma was prevalent among those bulimics with no recounting of anorexia. It was found that the condition was infrequent among the anorexic restrictors. Moreover, the subjects showed prevalence of effects of sexual trauma between the restrictors and the bulimics. In making the conclusion, the researchers said that sexual abuse and incest should not always be viewed as variables that cause the development of sexual disorders, because they can also be markers of developmental features, family histories, or any other pathogenic effects.

Bulimic Samples

Welch and Fairburn made a study of the connection linking sexual abuse and the development of bulimia nervosa. There were three main objectives in the study. The first objective was to make a determination of whether sexual ill-treatment leads to an increase of the risks of the development of bulimia nervosa and the researchers used 40 subjects who had bulimia nervosa and 80 normal subjects for comparison. The other objective of the study was to determine whether there was any risk increase identified that is particularly related to bulimia. Nervosa or whether there was a reflection of an increased risk of general psychiatric disorders. This was achieved by examining the 40 subjects anguishing from bulimia nervosa and 40 others with different psychiatric disorders. The third objective was to determine whether patients with bulimia nervosa had a difference with a community group as far as the history of sexual abuses was concerned. This was carried out by examining 50 community subjects who had bulimia nervosa and 50 clinical cases of the same condition.

After the research, the researchers found out that a very minor proportion of the subjects had a history of sexual abuse and they also found out that such a history was just as usual as in the group with the psychiatric disorders generally which means that sexual abuse cannot be considered as a particular risk factor that can lead to the development of bulimia nervosa. The other study used 700 bulimic women to determine whether there is a considerable involvement between bulimia and sexual abuses during childhood. A relationship between family environments was also studied and this study used the questionnaire method. A series of chi square and one way analysis were conducted and the researchers found out that bulimia with self reports of significant childhood abuse, sexually and the seriousness of the abuse was directly proportional to the severity of the bulimia. The contribution of the family environment was also noted where the family variables had an additive combination that increased the risk of bulimia. However, the researchers said that other factors still came into play like personality type, biological dispensation and other contextual factors because 38 percent of the women who had no childhood sexual abuse also displayed bulimic symptoms.

Psychiatric Inpatient Samples

The third group of researchers attempted to examine the connection between eating pathology and any form of abuse. They looked at the nature of this connection using a clinical sample population. In their hypothesis, they stated that patients with sexual abuse histories often show high levels of severe pathological eating disorders as compared to the women who did not suffer from nay type of sexual abuse. The study involved 140 psychiatric women patients, 90 of whom had a history of sexual abuse while 50 did not have such a history. The sample population was given self report questionnaires that had items that were behaviorally defined with a description of sexual abuse and an inventory of eating disorders. The researcher’s findings suggest that there is a relationship between general patterns of symptoms that are linked to sexual disorders (Welch and Fairburn, 1994).

Those patients with a history of childhood sexual abuse scored highly in this study as compared to the other group. However the subjects who had histories of childhood sexual disorders and were not diagnosed with any eating disorder still had some features bulimia nervosa and anorexia nervosa. This research shows that there is a very close association between sexual abuse and eating pathology and the patients with a history of childhood sexual abuse are bound to exhibit a higher level of eating pathology than the patients who did not suffer from childhood sexual abuse.

Student Samples

Student’s samples are also very important in the determination of the relationship between childhood sex abuse and the growth of eating disorders though this sample population ahs some limitations. The fourth research group used a sample of 150 female undergraduates in order to make a determination of a potential link between childhood sex abuse and eating disorders especially the onset of bulimia nervosa. It also investigated the role of family environment in the development of bulimia. The hypotheses that this group put across was that teenagers diagnosed as bulimics would report a higher rate of childhood sexual abuse than the ones that were not diagnosed with bulimia. To each of the participating subject, the following research protocol was provided: Subjects family background, sexual life events questionnaire, Dissociative experiences scale, childhood mealtime questionnaire and the bulimics investigatory test. The hypothesis of the researchers had tentative support form the bulimic group because it reported higher incidences of sexual abuse with a close relative or a family member after they were 12 years old and also reported more cases of sexual abuse with an adult before they were 12. The researchers say that high sexual abuse rates among the bulimics explains why they tend to have negative perception of their bodies (Henderson &Freeman, 1997).

The bulimics who reported sexual abuse, according to the research tend to significantly dissociate more that the bulimic women who had not been abused meaning that the binge purge cycles may create emotional numbness and psychological dissociation. As it was found in all the previous studies, it was not all bulimics that were found to have a history of sexual abuse. There were non bulimics who reported sexual abuse and some other bulimics who did not experience childhood sexual abuse. This means that there may be other factors that are operating outside the sexual abuse experience that lead to eating disorder development. The cases of bulimia would be more aggravated in women who have experienced both sexual abuse and other events that cause food disorders. The researchers also conducted another study suing the same sample population where it was revealed that any unwanted sexual experience would lead to a higher score on a scale measuring eating disorders. Dieting and bulimia were found to be connected to sexual experiences that used force especially where a close family member was involved. The researchers concluded that dieting or self starvation was a defenses mechanism, a way of gaining control over the family member with whom the sexual experience occurred, while bulimia may occur in situations where a person outside the family was involved. This is because the victim is not in a position to gain control over this perpetrator. Once again this fourth research has shown that sexual abuse has a high probability of triggering sexual disorders.

Incest Samples

The fifth research was carried out by wonderlich who used 40 women who were involved in an incest treatment program to make an exanimation of his hypothesis that victims of childhood sexual abuse show greater levels of eating disorders than the control subjects. The control subjects were 29 in number (Hastings &Kahn, 1994). The researcher had predicted that the victims of childhood stress disorders would have some other behaviors that reduce tension like substance abuse and the magnitude of the emotional reaction is directly related to the developing of eating disorders. This means that victims of childhood sex abuse often engage in dangerous self destructive behaviors aimed at minimizing the emotional stress that comes our of the abuse. They also found out that this bulimic behavior was related to the development of the symptoms of post traumatic stress disorder suggesting that bingeing, dieting and purging are some of the efforts that are employed by childhood sexual; abuse victims to manage their sensitive emotional; state that is usually imbalanced by memories of the abuse. The eating disturbances are related to reactions that are affective because of the travails of the abuse. The conclusion is that bulimic behaviors are purposely meant to create affective regulation and not reactions to thought of the abuse and memories of the ordeal.

Methods and Methodological Problems

Most of the studies aforementioned have succeeded in finding a connection between eating disorders and sexual abuse. The research designs used in the studies above present some methodological problems. One of the methodological problems is the size of the sample populations because may be somewhat different results on the negative or positive would have been gotten if the samples were large secondly the samples varied in their backgrounds, ranging form college students to psychiatric patients and this hinders making of generalizations in research because it is b\not known whether these problems are unique to those groups. The other problem is  lack of standard definitions of eating disorders and sex abuse which may affect the validity and the reliability of the research.  The studies did not use the same criteria for making the determination of whether eating disorders are cause by sex abuse meaning that it was difficult to make a conclusion using results got across different studies (Calam & Slade, 1989). The gathering of the retrospective information also posed a big problem because there was a potential bias in recall. This means that the individuals are more often than not, selective in the amount of information they are willing to give out especially things that happened in the past especially if the memory of those things hurts. The questionnaires used had also not been well validated and, measured to determine their reliability and validity. The questionnaires may also create a potential data bias.

Finally, the causal relationship between the histories of childhood sex abuse and the eating disorder development cannot be effectively determined though this kind of data gathered. This is because there is a serious lack of attention given to the timing of the abuse and the growth of the bulimia and anorexia nervosa and nothing is pout across to determine whether there were symptoms of eating disorders that existed before the sexual abuse (Benstein&Putnam, 1986). These researches conducted do not also pay attention to other potential factors such as the family environment that may lead to the development of the eating disorders. There are other victims of sexual; abuses that do not develop eating disorders meaning that the relationship between these two variables is very complex. All these research and methodological base problems act as a hindrance towards the understanding of the impact of sexual abuse on the development of eating disorders.

Conclusion

In all the research aforementioned that has been trying to analyze the relationship between eating disorders and sexual abuse, the data overwhelmingly suggests that there is a relationship between bulimia nervosa and sexual abuse. However, the data does not indicate that there is a relationship between sexual abuse and anorexia nervosa. Moreover, this relationship between childhood sex abuse and bulimia only exist \in some forms and not others meaning that a causal relationship is yet to be established. It is very possible that any traumatic happening has the potential of developing an n eating disorder given that sexual abuse occurs in environments that may engender such a development (Bond et al, 1983). The relationship between eating disorders and childhood abuse is not overt and it cannot be conclusively be said that the cause of eating disorders in women is childhood sex abuse because there are  those who experienced abuse and do not exhibit symptoms of eating disorders and others that have eating disorders and yet there were not sexually abuse while young. This means that there is more to eating disorders than just sexual abuse.

Future research ought to analyze the effects of the adjacent environment like family on the development of such disorders. This is because there are other traumas in the environment that may aggravate the eating disorders. These include physical and mental abuse. It is until some of the methodological shortcomings are mentioned above are resolved in the research designs of the future that the relationship between eating disorders and childhood sexual abuse will be established otherwise it would be fallacious to say that there is an overt relationship between the two variables. Despite all the reports of the above research designs, the connection between childhood sexual abuse and bulimia nervosa remains a mystery.

Statistical interpretations of the results

The Correlation between Child Sexual Abuse/Incest and Eating Disorders.

The independent variable: Child sexual abuse/no child sexual abuse.

The dependent variable: Eating Disorders.

The number of categories in my independent variable or my continuous independent variables are as follows: In the eating disorder dependent variable category; Anorexia Nervosa (Restricting) with a given value of 1.00, Anorexia Nervosa (Purging) with a given value of 2.00, Bulimia Nervosa with a given value of 3.00, ED (NOS) with a given value of 4.00, Obesity with a given value of 5.00 and no eating disorder reported with a given value of 6.00.  In the sexual abuse independent variable category child sexual abuse with a given value of 1.00, sexual assault with a given value of 2.00, attempted child sexual abuse with a given value of 3.00 and no sexual abuse reported with a given value of 4.00.

The statistics that I plan to run on my data would be the Correlate Spearman Rho as my categories don’t completely fall within those defined by Pearson are simply because both distributions are highly skewed.

The data output in comparing Eating Disorders with Sexual abuse using the Spearman Rho is as follows:

Nonparametric Correlations

Discussion of results

Most researchers have found out that just a small proportion of the subjects had a history of sexual abuse as they also found out that such a history was just as normal as in the group having psychiatric disorders thus considered as an independent variable. This shows that sexual abuse cannot be taken as a risk factor that can effectively lead to bulimia nervosa development thus a correlation coefficient of 3 which shows very minimal significance.

Students samples used in the determination of the relationship between growth of eating disorders and childhood sex abuse had some shortcomings and more so during the start of bulimia nervosa. The hypotheses that was forwarded was that teenagers diagnosed as bulimics would report a higher rate of childhood sexual abuse than the ones that were not diagnosed with bulimia thus non significant correlation.

The researchers were able to conclude that dieting or self starvation was a defense mechanism, a way of gaining control over the family member with whom the sexual experience occurred, while bulimia may occur in situations where an individual who is not part of the family member may get involved as the victim may not be in a situation to gain control over the perpetrator. The research based on Pearson’s correlation coefficient shows a value of 1 meaning that sexual abuse has a very high chance of bringing about eating disorders.

The research carried out by Wonderlich using women who were involved in an incest treatment program showed greater levels of eating disorders than the control subjects. As earlier predicted the victims of childhood stress disorders would engage in some behaviors in order to reduce tension such as substance abuse and the extent of the emotional reaction has a direct relation to eating disorders development thus potentiating a correlation coefficient of 3. This then shows that victims of childhood sex abuse most of the time engages in weird self destructive behaviors that are geared towards lowering the emotional stress.

The findings which show that this kind of bulimic behavior was significantly related to the emergence of the symptoms of post traumatic stress disorder hence suggesting that dieting and purging are amongst the efforts employed by childhood sexual and victims of abuse to effectively manage their emotional; state that is usually imbalanced by memories of the abuse. The eating disturbances owed some relation to eventual reactions as a result of the abuse.

The attempt by some researchers to examine the link between any existing form of abuse and eating pathology by looking at the nature of the connection using a clinical sample population. The hypothesis stated that most patients with histories of sexual abuse do exhibit elevated levels of extreme pathological eating disorders as compared to the women who did not suffer from any type of sexual abuse.

In relation to a study where the sample population was given self report questionnaires containing items with behavioral definition and description of sexual abuse with an inventory of eating disorders. The findings suggest that there is a relationship between symptoms that are associated with sexual disorders thus a correlation coefficient of 1. It shows that there is a very close association between sexual abuse and eating pathology and most individuals with a history of childhood sexual abuse are most likely to exhibit higher levels of eating disorders than individuals who were not victims of the same in childhood.

The statistical data showed a lot of similarity with the correlation significance thus the findings reflects true picture of the relationship between Child Sexual abuse, incest and eating disorders. However the results can not be conclusive because of human errors as some respondents can not reveal the truth.

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