Eventos epigenéticos como o imprinting genômico e a inativação do cromossomo X (ICX), já foram amplamente estudados em camundongos. Nesses animais muitos dos processos epigenéticos que levam à ICX já estão profundamente esclarecidos. Em humanos entretanto, o conhecimento sobre a ICX é mais limitado, em particular os eventos iniciais do processo durante o desenvolvimento embrionário. O desenvolvimento e aprimoramento de ensaios que envolvem o sequenciamento em larga escala do transcriptoma (RNA-Seq) de células únicas iniciam uma nova era nos estudos sobre a ICX. São crescentes os dados de RNA-Seq depositados em bancos de dados públicos e em 2013 os trabalhos de Xue e colaboradores e de Yan e colaboradores tornaram disponíveis os resultados de RNA-Seq de células individuais isoladas de embriões humanos a partir do estágio de duas células até a fase de blastocisto. Através de técnicas de bioinformática avaliamos o nível de expressão do gene XIST, intimamente envolvido no processo de ICX, nos diferentes estágios do desenvolvimento. Alinhamos também as leituras geradas por RNA-Seq contra o genoma humano de referência no intuito de se identificar variantes em regiões transcritas e assim verificar a origem do alelo expresso. Com isso, pudemos observar que o gene XIST tem sua expressão iniciada em embriões humanos no estágio de oito células, e que o silenciamento transcricional dos genes do cromossomo X já se iniciou no estágio de blastocisto de forma aleatória mas ainda não se disseminou, i.e. a ICX não está completa. Devido ao fenômeno de ICX, a caracterização de genes \"imprintados\" neste cromossomo é desafiadora. Ainda assim em camundongos foram relatados alguns genes do X que são assim regulados. Mulheres portadoras da síndrome de Turner (45,X) apresentam diferenças fenotípicas dependentes da origem parental do cromossomo X herdado, sugerindo a existência de genes \"imprintados\" no X humano. Em particular os genes MAOA, MAOB e USP9X foram indicados como candidatos a serem regulados por imprinting. Através do sequenciamento de regiões transcritas contendo SNPs em heterozigose foram avaliados o padrão de expressão alelo-específico dos três genes indicados. Nenhum sinal de regulação por imprinting pôde ser detectado nem em placenta nem em cérebro humano, pois a procedência dos alelos expressos era independente da origem parental. Isso não significa que a variabilidade fenotípica em mulheres com Turner não possa ser explicada por imprinting em genes do X. Experimentos de RNA-Seq em diversos tecidos humanos ou a partir de células únicas são uma abordagem conveniente para se elucidar este fenômeno / Epigenetic phenomena as genomic imprinting and X chromosome inactivation (XCI) have been widely studied in mice. While most of the processes and steps involved in XCI in mice are well studied, in humans our knowledge is still very limited, specially during early embryo development. Advances in single-cell whole transcriptome high troughput sequencing techniques (RNA-Seq) bring a new era to the XCI field. Single-cell RNA-Seq results of from 2-cell to the blastocyst stage of human embryos were published by Xue et cols and Yan et cols in 2013. Using bioinformatics techniques we searched for the XIST gene expression level (a gene closely involved in XCI) throughout the human pre-implantation embryo development. We aligned reads generated by RNA-Seq assays to the human reference genome looking for variants in gene transcriptional regions and to identify the origin of the expressed allele. Our results show that XIST expression starts from the 8-cell stage and is stabilized and upregulated at the female blastocyst stage. We also show that the transcriptional silence of X-linked genes started at the blastocyst stage and is independent of parental origin but this does not apply for all genes. We concluded that the completion of the transcriptional silence step is probably established during post-implantation stage. The search for X-linked imprinted genes is challenging due to the XCI phenomenon. Nevertheless, X-imprinted genes were reported in mice. In humans, no X-imprinted genes were found so far, but phenotypic differences reported in Turner\'s syndrome (45,X) women was related to the parental origin of the X chromosome inherited. This suggests the existence of X-linked imprinted genes, in particular MAOA, MAOB and USP9X seemed good candidates. By sequencing transcript regions containing heterozygous SNPs in these genes we could access their expression pattern. Our results show no sign of imprinting regulation of MAOA, MAOB and USP9X, neither in human brain nor in human term placenta. This does not rule out the possibility that the phenotypic differences observed in Turner\'s syndrome women could be the consequence of other unknown X-linked imprinted genes. RNA-Seq of different human female tissues is a powerful approach to finally find the genes involved in such phenotypes

Vários mecanismos controlam os processos de contração e relaxamento das células musculares lisas vasculares (CMLVs). Receptores e moléculas sinalizadoras intracelulares, os quais controlam os processos de contração e relaxamento das CMLVs, são alvo de modificações pós-traducionais, como a O-GlcNAcilação que modula respostas vasculares. O aumento de proteínas modificadas por O-GlcNAc apresenta efeito ambíguo sobre as CMLVs, sendo protetor em situações de aumento agudo, mas lesivo quando mantido cronicamente. O aumento crônico de O-GlcNAc em animais está associado a repostas contráteis mais intensas e redução do relaxamento vascular, assim como o aumento da produção de espécies reativas de oxigênio (EROs), denominado estresse oxidativo, alterações constantemente descritas em doenças crônicas como diabetes e hipertensão arterial. Considerando que algumas proteínas que controlam a contratilidade vascular são modificadas por O-GlcNAc e que pouco se sabe a respeito da via de Biossíntese das Hexosaminas (VBH) e sua relação com o sistema vascular em humanos, nós investigamos a hipótese de que modificações de proteínas por O-GlcNAc estão relacionadas a alterações vasculares na hipertensão arterial em humanos. Durante a realização de nossos experimentos, demonstramos que os principais componentes da VBH estão presentes em CMLVs humanas. O tratamento com Thiamet G (TMG) por 24 h aumentou os níveis de proteínas modificadas por O-GlcNAc nas CMLVs pela redução da atividade de OGA, assim como induziu efeito compensatório de aumento da expressão dessa enzima. TMG reduziu a atividade de OGA em CMLVs no grupo Controle, mas não promoveu alteração na geração de EROs. Após tratamento com TMG, artérias de grupo Controle apresentaram maior sensibilidade à noradrenalina (NA) e maior relaxamento ao nitroprussiato de sódio (NPS); enquanto o grupo Hipertenso não apresentou alterações na contratilidade ou no relaxamento arterial. Artérias do grupo Hipertenso apresentaram maior sensibilidade à NA que o grupo Controle antes de qualquer tratamento, além de deficiência no relaxamento, com menor sensibilidade e menor resposta máxima ao NPS em comparação ao grupo Controle. O grupo Hipertenso apresentou aumento da pressão arterial média de internação (PAMi), assim como da idade, quando comparado com o grupo Controle. Em conclusão, a VBH está presente nas CMLVs humanas. A inibição da atividade da OGA por TMG aumenta os níveis de proteínas modificadas por O-GlcNAc, a expressão de OGA e modula a reatividade vascular no grupo Controle, mas não no grupo Hipertenso. Os resultados demonstram que pacientes hipertensos apresentam respostas vasculares a drogas vasoativas diferentes daquelas observadas em pacientes controle, antes e após o aumento dos níveis de proteínas modificadas por O-GlcNAc nas CMLVs. Novos estudos serão necessários para determinar se as alterações observadas são decorrentes da hipertensão arterial e/ou do tratamento farmacológico aos quais os pacientes estão submetidos. / Several mechanisms control the contraction and relaxation processes in the vascular smooth muscles cells (VSMC). Intracellular receptors and signaling molecules involved in contraction and relaxation mechanisms are targets of post-translational modifications (PTM), such as O-GlcNAcylation, which modulates vascular responses. Augmented levels of O-GlcNAc-modified proteins show a dual effect in VSMC, being protective during acute stressful events and deleterious when O-GlcNAc is chronically augmented. In animals, chronic increases in O-GlcNAc-modified proteins are linked to increased vascular responses to constrictor agents, to reduced vascular relaxation in response to dilator drugs, and to increased production of reactive oxygen species (ROS), named oxidative stress. All these changes are frequently described in chronic diseases such as diabetes and arterial hypertension. Since proteins involved in vascular contractility are modified by O-GlcNAc, and our knowledge on the influence of the hexosamine biosynthesis pathway (HBP) in the human vascular system is limited, we tested the hypothesis that proteins modified by O-GlcNAc contribute to vascular changes in hypertensive patients. Our data show that human VSMC express the main components of the HBP; the treatment of human VSMC with Thiamet G (TMG) for 24 h augmented O-GlcNAc levels, decreased OGA activity and induced a compensatory increase in OGA\'s expression. TMG reduced OGA activity, increased levels of O-GlcNAc-modified proteins but did not change ROS generation in human arteries from the Control group. After treatment with TMG, arteries from the Control group exhibited increased sensitivity to norepinephrine (NE) and to sodium nitroprusside (SNP), as well as increased maximum relaxation to SNP. Augmented O-GlcNAc levels produced no changes in contractile or relaxation responses in the Hypertensive group. Arteries from the Hypertensive group exhibited an increased sensitivity to NE as well as decreased sensitivity and maximum relaxation to SNP when compared to arteries from the Control group. Mean arterial blood pressure (hMABP) and the average age were increased in patients from the Hypertensive group. In conclusion, the HBP is present in human VSMC and the inhibition of OGA activity with TMG increases O-GlcNAc levels, increases OGA expression and modifies vascular responses to constrictor and dilator stimuli in human arteries from the Control group, but not from the Hypertensive group. These results indicate that hypertensive patients have altered vascular responses to vasoactive drugs both in the absence and in the presence of augmented O-GlcNAc levels. Further research is needed to explain whether these differences are due to the hypertensive disease and/or to the patient\'s medical treatment.

As classes de equivalência de estímulos são produto das contingências de reforço. No entanto, as pesquisas têm utilizado apenas contingências de reforço positivo e investigado, na sua maioria, como eventos relacionados a um mesmo reforçador podem passar a compor uma mesma classe. O objetivo do presente trabalho foi avaliar o efeito de diferentes contingências de reforço, positivo e negativo, no estabelecimento de discriminações condicionais na formação de classes de equivalência em humanos. Foram realizados dois experimentos. No Experimento I, 12 participantes treinaram simultaneamente 12 relações condicionais (AB e BC) utilizando três arranjos de contingência de reforçamento diferentes: reforçamento positivo (Ganhar/Manter), reforçamento negativo (Manter/Perder) e uma contingência mista de reforçamento negativo e positivo (Ganhar/Perder), seguidos de testes de formação de classes de equivalência. No Experimento I, os participantes expostos aos testes de equivalência acertaram todas as tentativas de teste. Estes resultados demonstram a possibilidade de formação de classes de equivalência em uma contingência de reforço negativo, porém um possível efeito de teto impede a comparação de cada contingência na formação de classes. No Experimento II, sete participantes foram expostos ao treino de 12 relações condicionais, com classes com um maior número de nódulos (AB, BC e CD) utilizando apenas duas contingências de reforço (Ganhar/Manter e Manter/Perder). Em ambos os experimentos, a sequência de aquisição das discriminações e o viés inicial produzido pelas contingências de reforço negativo sugerem um impacto diferencial da punição em relação ao reforçamento. Os resultados nos testes de equivalência sugerem que a formação de classes é menos provável quando utilizada uma contingência de reforço negativo em relação a de reforço positivo. Foi discutida a generalidade da formulação sobre formação de classes de equivalência, priorizando os padrões de controle de estímulos produzido pelas diferentes contingências. Ressalta-se a necessidade de maior investigação sobre quais os efeitos do uso de contingências aversivas no controle da resposta e mais especificamente no controle de estímulos / Equivalence classes are produced by reinforcement contingencies, however, research have used exclusively positive reinforcement and investigated mostly how events related to a same reinforcer may result in the formation a same class. The aim of this study was to evaluate how different reinforcement contingencies affect the acquisition of conditional discriminations and equivalence class formation in humans. Two experiments were conducted. In Experiment I, 12 participants learned 12 conditional relations (AB BC) under three different contingencies: positive reinforcement (Gain/Maintain), negative reinforcement (Maintain/Lose) and a mixed contingency (Gain/Lose). Equivalence class test were applied subsequently. In Experiment I, participants that underwent the equivalence tests performed correctly in all trials, although a roof effect might have prevented a proper comparison of the contingencies effect. In Experiment II, seven participants learned 12 conditional relations with more nodes (AB, BC e CD) and two reinforcement contingencies (Gain/Maintain and Maintain/Lose). In both experiments, the conditional discrimination acquisition sequence and the initial bias produced by the negative reinforcement contingency suggest a differential effect of punishment in relation to reinforcement. The equivalence test results suggest the possibility of equivalence class formation using a negative reinforcement contingency and indicate that equivalence classes are less probable using a negative reinforcement contingency than a positive reinforcement one. The generality of the equivalence class formulation was discussed emphasizing the investigation of stimuli control patterns produced by the contingencies. The lack of knowledge about stimulus control produced by aversive contingencies was highlighted

<p>Hepatitis E virus (HEV) je uzročnik akutne hepatis E infekcije kod ljudi. HEV se prenosi putem zagaĎene vode i odgovoran je za nastanak mnogobrojnih epidemija velikih razmera u zemljama u razvoju Azije i Afrike. Hepatitis E je prvi put kod svinja izolovan 1997. godine, a kasnije je dokazan i kod ostalih ţivotinjskih vrsta, kao &scaron;to su: divlje svinje, jelen, zečevi, pacovi, ptice i ostalo.<br />Prva istraţivanja prisustva HEV infekcije kod domaćih i divljih svinja u Srbiji sprovedena su 2008. godine. HEV RNK je dokazana u 30% uzoraka fecesa i 45% uzoraka organa (Petrovic et al., 2008). Analizom uzoraka krvnih seruma svinja u individualnim gazdinstvima ustanovljena je seroprevalencija od 34,6% (Lupulovic et al, 2010). Cilj ovog istraţivanja je ispitivanje ra&scaron;irenosti HEV infekcije kod svinja na farmama na teritoriji Vojvodine, kao i ispitivanje HEV seroprevalencije kod ljudi u Vojvodini.<br />Od metoda za istraţivanje kori&scaron;ćene su: nekomercijalni ELISA test (in-house ELISA), komercijalni ELISA test, Western-blot metod, real-time RT -PCR i imunohistohemijska metoda za detekciju HEV antigena.<br />Materijal za ispitivanje su bili uzorci krvi svinja (300) sa 3 farme na teritoriji Juţne Bačke i Srema i uzorci krvi ljudi (294), kao i uzorci fecesa, ţuči, jetre i mesa sakupljeni u klanicama od 95 tovljenika i 50 prasadi.<br />Prisustvo specifičnih antitela IgG klase protiv hepatitis E virusa dokazano je kod svinja na sve tri ispitujuće farme. Primenom in house ELISA testa ustanovljena je seroprevalencija od 37% na farmi A, 31% na farmi B i 54% na farmi C, dok je primenom komercijalnog ELISA testa utvrĎeno 40% seropozitivnih svinja na farmi A, 41% na fami B i 65% na farmi C. Uporednom analizom rezultata dobijenih sa oba ELISA testa, ustanovljena je prosečna seroprevalencija od 40,66% in house ELISA testom, odnosno 48,66% komercijalnim ELISA testom.<br />Sprovedena su i istraţivanja prisustva specifičnih antitela IgG klase protiv HEV u krvnim serumima dobrovoljnih davalaca krvi i kod pacijenata. Primenom in house ELISA testa utvrĎena je<br />seroprevalencija od 15% kod dobrovoljnih davalaca krvi, dok su uzorci krvi pacijenata bili seronegativni. Testiranjem komercijalnim ELISA testom kod dobrovoljnih davalaca krvi pozitivan serolo&scaron;ki nalaz je ustanovljen kod 17,86% dobrovoljnih davalaca krvi (pregledani su serumi koji su u in house testu dali pozitivan ili sumnjiv nalaz, kao i odreĎen broj seronegativnih uzoraka), a kod pacijenata 2,12%.<br />Kao tzv. &bdquo;zlatni standard&ldquo; za definisanje rezultata sa sumnjivim serolo&scaron;kim nalazom čije su ekstinkcije bile blizu cut off vrednosti u in house ELISA testu, kori&scaron;ćen je Western blot metod. Pozitivan rezultat je potvrĎen kod 6 od ukupno pregledanih 11 uzoraka krvi svinja, odnosno od ukupno pregledanih 11 uzoraka seruma ljudi, pozitivan nalaz je ustanovljen kod 7 uzoraka.<br />Uzorci sa klanica pregledani su real-time RT- PCR metodom, a HEV RNK je dokazana u u fecesu (54%), ţuči (26%), jetri (16%) i mesu (10%) prasadi. Kod tovljenika prisustvo HEV RNK je potvrĎeno samo u fecesu (7,27%), dok su svi uzorci tkiva bili negativni.<br />Patahistolo&scaron;kim pregledom dokazane su mikroskopske lezije II stepena kod 3 uzorka (11,53%) jetri prasadi od ukupno pregledanih 26 uzoraka sa pozitivnim RT-PCR. Imunohistohemijskim pregledom uzoraka jetre prasadi nije dokazano prisustvo antigena hepatitis E virusa.<br />Definisani su protokoli laboratorijskog ispitivanja hepatitis E infekcije kod svinja i ljudi, kao i u uzorcima mesa i jetri svinja u klanicama</p> / <p>Hepatitis E virus (HEV) is the causative agent of acute hepatitis E infection in humans. HEV is transmitted through contaminated water and is responsible for the outbreaks of many large-scale epidemics in the developing countries of Asia and Africa. Swine HEV was first isolated in 1997, and was later detected in other animal species, such are: wild boar, deer, rabbits, rats, birds and more.<br />The first investigations of HEV infection in domestic and wild pigs in Serbia were carried out in 2008. HEV RNA was detected in 30% of faecal samples and 45% of the tissue samples (Petrovic et al., 2008). Analysing the blood samples of beckyard pigs, the seroprevalence of 34,6% was determined (Lupulovic et al, 2010). The aim of this study was to investigate the prevalence of HEV infection in pigs on farms in Vojvodina, as well as testing the HEV seroprevalence in humans.<br />The methods used for this study were: non-commercial ELISA (in house ELISA), the commercial ELISA, Western blot method, real-time RT-PCR and immunohistochemical method for the detection of HEV antigen.<br />Material for the study were: blood samples of pigs (300) from 3 farms on the territory of South Backa and Srem and blood samples of people (294), as well as faeces, bile, liver and meat collected in slaughterhouses from 95 fatteners and 50 piglets.<br />The presence of specific IgG antibodies against the hepatitis E virus in pigs has been detected on all three examinated farms. Upon the application of in house ELISA, the seroprevalence of 37% was establised on farm A, 31% in farm B and 54% on farm C, while using a commercial ELISA , 40% of seropositive pigs were detected on farm A, 41% of fami B and 65% Farm C. The comparative analysis of the results obtained with both ELISA, determined the average seroprevalence of 40,66% by in house ELISA and 48,66% by commercial ELISA.<br />The research of the presence of specific IgG antibodies against HEV in the serum of blood donors and patients were also conducted. Upon the application of in house ELISA, the seroprevalence of 15% were recorded in blood donors, while blood samples of patients were seronegative. Testing by commercial ELISA, positiv serological findings were diagnosed in 17,86% of blood donors (serums with positive or suspicious results in in house ELISA and a number of seronegative samples were tested), and in patients 2, 12%.<br />As so-called &quot;gold standard&quot; for defining the serological results with suspiciousserological findings, which extinctions were close to cut off values in in house ELISA, we used the Western</p>

Melioration can be a factor contributing to behavioral addiction. In this study, 76 university undergraduates operated a "money machine" by selecting between choices that corresponded to maximization and melioration. Participants initially made choices consistent with a strategy of melioration and demonstrated significantly greater variability in choice behavior when visual cues were presented aimed at exposing the internality (or consequence) of the choice situation. Removal of the visual cues resulted in a return to lower responding. Visual cues may aid in interrupting the behavioral addiction pattern by limiting exclusive use of a melioration choice strategy. Methods of restructuring and experimentation with choice allocations are suggested as possible alternatives to melioration.

Tesis (magíster en derecho económico, inversiones, comercio y arbitraje internacional) Universidad de Chile, Universidad de Heidelberg / In 2010 a malicious computer worm attacked Iranian nuclear facilities in Natanz. It was the first computer worm that caused physical damage, and because of this, Iran had to suspend its nuclear program approximately for two years. The case caused great concern among the international community and raised the issue of protecting the population. This paper will address the issues of cyber war and its relationship with International Humanitarian Law and International Human Rights Law.

Le système immunitaire inné est un mécanisme de défense commun à tous les métazoaires. Son activation peut être délétère lorsqu'elle est incontrôlée. L'étude des mécanismes qui sous-tendent cet équilibre entre l'activation ou non de la réponse immunitaire innée est à la base de mes travaux de thèse. La similarité entre les voies moléculaires - comme la voie NF-KB - relayant la réponse immunitaire innée chez les insectes et les mammifères fait de la drosophile un excellent modèle pour explorer la réponse immune. Après une stimulation immunitaire, l'arrêt des voies moléculaires de l'immunité est nécessaire pour éviter le développement de maladies auto-immunes ou du cancer. Mon premier projet s'est attaché à comprendre un mode de régulation original dépendant du temps, dans une des voies NF-KB de la drosophile. Mon deuxième projet··concerne l'activation de la réponse immunitaire. Une· protéine nucléaire contrôle l'implication de machinerie épigénétique dans le contrôle de l'expression d'une des voies NF-KB de la drosophile. Le tout permet de mieux saisir la dynamique de régulation de la réponse innée. / The innate immune system is a defense mechanism common to all metazoans. lts activation can be deleterious when it is uncontrolled. The study of the mechanisms underlying this balance between the activation or not of the innate immune response is the basis of my thesis work. The similarity of the molecular pathways - such as the NF-KB pathway - relaying the innate immune response in insects and mammals makes Drosophila an excellent model for exploring the immune response.After immune stimulation, stopping the molecular pathways of immunity is necessary to prevent the development of autoimmune diseases or cancer. My first project focused on understanding a time-dependent mode of regulation in one of Drosophila's NF-KB pathways. My second project concerns the activation of the immune response. A nuclear protein contrai the involvement of epigenetic machinery in controlling the expression of one of Drosophila's NF-KB pathways. Ali this makes it possible to better grasp the dynamics of regulation of the innate response.

Two experiments were undertaken. The objective of Experiment One was to identify the lower limb muscles that were most frequently active during the early period of a step turning task for further testing in Experiment Two. In Experiment Two participants undertook multiple trials of a step-turning task, 30 and 60° to the left and right of midline, at a self-selected pace in response to a visual cue. There were five objectives to Experiment Two. Firstly, to identify the predominant order in the onset of foot movement so that anticipatory muscle activity could be defined for this task. Secondly, to identify whether there is a consistent temporal order in movement onset between the head and the feet. Thirdly, to identify whether and how consistently anticipatory lower limb muscle activity is present bilaterally. Fourthly, to assess whether there is a consistent sequence in the onset of anticipatory muscle activity among muscles active in at least 80% of trials. The final objective was to identity whether there was a consistent temporal relationship in the onset of the anticipatory muscle activity present in at least 80% of trials, with the onset of head and foot movement. Study Design: A repeated measures design was used. Background: Anticipatory lower limb muscle activity in gait initiation and forward stepping studies has been reported to be consistently present, and associated with initial and important balance responses. Falls during turning are associated with a high incidence of hip fractures in the elderly population. The presence of anticipatory lower limb muscle activity turning has not been previously reported. Participants: There were five participants in Experiment One, and ten in Experiment Two. All were between 18 and 40 years of age and did not have neurological or musculoskeletal disorders, or severe visual loss. Results: In Experiment One, four muscles were consistently active bilaterally, during the early period of step-turning and were: tibialis anterior, gastrocnemius, biceps femoris and gluteus medius. In Experiment Two the ipsilateral foot moved before the contralateral foot in 68% of trials towards the left, and 79% of trials towards the right. The onset of head movement consistently occurred before the onset of foot movement during turns towards both directions. The percentage of trials in which the four muscles were active in an anticipatory manner was low bilaterally, ranging from 12 to 38% of trials. Objectives that involved the further analysis of muscles active in at least 80% of trials were unable to be completed. Conclusions: During a step-turning task young healthy adults predominantly move their ipsilateral foot before their contralateral foot. The consistent onset of head movement prior to that of the feet, indirectly suggests that the visual system might influence the temporal onset of the feet. The low levels of anticipatory muscle activity during step-turning suggest that the lower limbs are not involved with the initial balance responses for this task thus making it inherently different to gait initiation and forward stepping.

Judging time-to-contact with a target is an important criterion for avoiding harm in everyday walking and running tasks, and maximizing performance in high-velocity sporting tasks. The information-based regulation of step length and duration during target-directed locomotion was examined in relation to gait mode, approach velocity, target task, expertise, and sporting performance during a series of four experiments. The first three experiments examined novice performers (Each n=12, 6 males, 6 females), whilst the last experiment examined expert gymnasts (n=5). Two reference strips with alternating 50cm black and white intervals were placed on either side of the approach strip for all of the experiments. One 50Hz-panning video camera filmed the approach from an elevated position. In Experiment 4, two stationary 250Hz cameras filmed the post-flight performance of the gymnastic vaults and, in addition, two qualified judges provided a performance score for each vaulting trial. The panning video footage in each experiment was digitized to deduce the gait characteristics. In Experiment 4, the high-speed video footage was analyzed three-dimensionally to obtain the performance measures such as post-flight height. The utilization of visual stimulus in target-directed locomotion is affected by the observer's state of motion as characterized by the mode of locomotion and also often the speed of locomotion. In addition, experience plays an important role in the capacity of the observer to utilize visual stimulus to control the muscular action of locomotion when either maintaining or adjusting the step mechanics. The characteristics of the terrain and the target also affect the observer's movement. Visual regulation of step length decreases at higher approach speeds in novice performers, where as expert performers are capable of increasing visual regulation at higher approach speeds. Conservatism in final foot placement by female participants accounts for the observed increase in distance from the critical boundary of the obstacle relative to toe placement. Behavioural effects of gender thus affect the control of final foot placement in obstacle-directed locomotion. The visual control of braking in target-directed locomotion is described by a tau-dot of-0.54. When tau-dot is below -0.54 a hard collision with the obstacle will occur, however, when tau-dot is above -0.54, a soft collision with the target will occur. It is suggested that the tau-dot margin defining the control of braking reveals the braking capacity of the system. In the target-directed locomotion examined a tau-dot greater than -0.70 would possibly exceed the braking capacity of the system, thus, leading to injury if performed. The approach towards the take-off board and vaulting horse in gymnastics is an example of target-directed locomotion in sport. Increased visual regulation of the timing and length of each step is a requirement for a fast running approach, a fundamental building block for the execution of complex vaults in gymnastics. The successful performance of complex vaults in gymnastics leads towards a higher judge's score. Future research suggestions include an investigation of visual regulation of step length in curved target-directed locomotion.

Repetitive injuries have been a major obstacle in production assembly lines all over the world. These injuries have greatly reduced the production efficiency of assembly plants and also negatively affected human health. Various attempts have been made by the Canadian government through the Workers Compensation Board (WCB) to prevent the occurrences of these injuries because of the associated cost and effects. These attempts failed as the cost of injuries acquired in the workplace continues to increase. For example, in New Zealand alone, the total cost of accidents in 2005, is estimated at $300 million (Accident Compensation Corporation, 2005). In Canada, the number of accepted claims alone amount to 15623 people (Workers Compensation Board of Canada, 2003).<p>A human body can be viewed as a mechanism that is composed of links and joints controlled by a central nervous system and are subject to stress, strain, fatigue and failure as can be observed on a regular industrial robot. But unlike the robot which is designed proactively, these stress and strain factors could be because of certain conditions such as inappropriate work posture, poor assembly line design, excessive workload, and poor work conditions. <p>Often, it is almost uncertain to make a conceptual assessment of the appropriate ergonomic design of a production system before the assembly line is built and put in use. This research will propose a general computer-based methodology for analysis of work injuries given an assembly line where human workers perform repetitive operations. The general methodology integrates sophisticated computer software systems for biomechanics simulation with various manual measurement techniques and methods. The research further proposed a simple and handy synthesis method with which problematic areas of assembly line design, with special reference to human work design can be identified and improved. The proposed methodology for analysis and synthesis is then implemented in a real assembly line to understand the effects of different work activities on the human body. Various software packages and motion tracking techniques will be considered prior to the actual implementation of the final methodology. A rule of thumb table will also be presented as a guideline for the re-design process. The research also proposed a general procedure and specific formula within a specific regional context to calculate the costs of worker injuries in real-life assembly system. This formula thus allows us to obtain the total cost of injuries in a production assembly line, making it possible to optimize the design and operation of the assembly line.