PURPOSE: Muscle overuse is characterized by inflammation, reduced strength and muscle damage. It has been proposed that calcium (Ca2+) accumulation during muscle contraction, is responsible for muscle damage. Muscle contractile properties are regulated by calcium regulatory excitation contraction coupling mechanisms. Therefore, the main aim of the present study was to investigate the effects of voluntary repetitive tasks during six weeks on the rate of sarcoplasmic reticulum (SR) Ca2+-uptake, and Ca2+-release, in young female Sprague-Dawley rats. Secondly, this study aims to evaluate the effect of the training on muscular strength and the relationship between SR Ca2+-kinetics and grip strength test performance. METHODS: Six rats were trained (EXP), using a well-established model of reaching and handle pulling with the upper extremities (2 hr/day, 3days/week, 6 weeks), six control rats (KON) were included that were not exposed to the task. Grip strength were evaluated using a grip strength meter for rodents, two weeks prior the training was initiated, and two days after the training period was concluded. Tissue samples were obtained from the supraspinatus and trapezius muscle, and the rate of SR Ca2+-uptake and SR Ca2+-release were analysed using the fluorescent Ca2+ indicator indo 1. RESULTS: The analysis revealed that EXP had a significant higher rate of SR Ca2+-uptake, in both supraspinatus (33%, P < 0,05) and trapezius (14%, P < 0,05), compared to KON. However, no significant differences in SR Ca2+-release rate were found between groups, in neither of the muscles. A decline in grip strength were found in both EXP and KON, with no significant differences between groups. No significant correlation between grip strength and the Ca2+ release uptake variables could be found. CONCLUSION: The present results suggests that repetitive voluntary reaching and handle pulling with the upper extremities during six weeks, induce extant changes in SR Ca2+-uptake rate in rats.

These compositions explore concepts based on processes and polymeter. Drawing on influences ranging from Steve Reich to Conlon Nancarrow and Nik Bärtsch they use and develop an approach to rhythmic thinking based on ostinati constructed of layers of different speeds. Through the use of click tracks, they look at how an ensemble can be enabled to perform rhythms that, without the electronic support, would be unplayable – crossing a line between the possible and the impossible. By means of processes built on a number of different ideas, the pieces explore how these can be used to affect both the behaviour and evolution of musical material, as well as using them to create fixed structures within which I then move subjectively and more intuitively. The question of balance, of moving between two points or approaches that are seemingly opposites, has also been examined: looking at how the journey affects the destination, where the simple becomes complex, and where personal meets impersonal.

Objective: Theoretical and empirical evidence suggests a relationship between Repetitive Thought (RT, e.g. rumination), and depression in patients with Coronary Heart Disease (CHD). To date, cross-sectional studies indicate that rumination is associated with depression in CHD, but additional prospective longitudinal research is required to determine if rumination predicts subsequent depression. This research therefore aimed to test the hypothesis that RT, specifically rumination, is a vulnerability factor for depression over time in a CHD population. It was predicted that RT at baseline would predict depression rates at three month follow-up after controlling for baseline depression and potential confounding factors. Methods: Inpatients and outpatients with a diagnosis of CHD completed self-report questionnaires at baseline (N = 101) and at three month follow-up (N = 85). The data was analysed using a hierarchical multiple regression. Results: Baseline rumination significantly predicted depression at the three month follow-up after controlling for baseline depression and potential confounding factors. Rumination accounted for 8.3% of the variance (p< .001). Subscales of brooding and reflection were also found to be individually predictive of follow-up depression explaining 4% of the variance (p< .005) and 7% of the variance (p< .001) respectively. Conclusion: Findings are consistent with previous prospective and cross-sectional research that indicates that rumination plays a unique role in the maintenance of depression in CHD patients and is an identifiable vulnerability factor.

MSc (Occupational Therapy), Faculty of Health Sciences, University of the Witwatersrand / Ergonomic interventions, addressing work and lifestyle factors, seem more effective in reducing computer related upper limb repetitive strain injury (RSI).This study considered the efficacy of such a programme on the resolution of RSI symptoms. A cross sectional survey, of 325 computer workers in a medical aid company call centres, in Gauteng, South Africa was used to establish a point prevalence of 30.23% for RSI symptoms, which correlates with those found elsewhere. An occupational therapy ergonomic intervention was then designed and piloted for efficacy. A randomised control trial conducted on 37 participants with RSI used the programme and computer generated “Break Software”. The six week intervention included the assessment of: three physical outcome measures and lifestyle factors for, the experimental and control groups. Results indicated positive effects on pain, grip strength, and lifestyle factors including feelings of inefficiency, pressure at the end of the day, depression and work capacity, but little extrapolation of ergonomic knowledge to the workplace.

Repetitive behaviors are a core symptom of autism spectrum disorders. They represent a major barrier to learning and social adaptation, affect levels of engagement in life situations, communication, social interactions and sustain social connections. Repetitive behaviors are often managed using exercise-based interventions which have been suggested to reduce repetitive behaviors and benefit mental health and behavioral functioning of individuals with ASD. The purpose of this systematic review was to explore and critically review the findings of previous studies examining effects of various exercise-based interventions on reducing autistic repetitive behaviors in children with autism spectrum disorder. Searches were limited to peer-reviewed studies written in English and published between Jan.2008- Jan. 2019. Only studies focusing on physical exercise-based interventions aiming to decrease repetitive behaviors as a symptom of an autistic spectrum disorder were included. Quality of articles included in the review was assessed using the Joanna Briggs checklists. Two researchers were involved in the quality assessment process, and any discrepancies were resolved through discussion. 5 studies were included in the final review. All studies examined the effects of short term exercise interventions on repetitive behaviors in children with ASD. There was no consistency across studies regarding types or duration of interventions, sample sizes or demographics of participants. However, the findings of the studies examined in this review provide a moderate to strong evidence that exercise-based interventions decrease repetitive behaviors. The studies reviewed included clinically relevant findings that can be used and adapted to fit different needs of children in future interventions. However, additional research using stronger and more varied designs, would be needed to determine the most beneficial types of exercise- based interventions for decreasing repetitive behaviors.

A localização cromossômica do DNA ribossômico (rDNA) foi estudada em cromossomos politênicos e em tecidos diplóides de quatro espécies de sciarídeos: Trichosia pubescens; Rhynchosciara americana; R. milleri e Schwenkfeldina sp.. Resultados de hibridação em cromossomos mitóticos mostraram a existência de um único locus de rDNA; entretanto, sondas ribossomais hibridaram em mais de uma região dos cromossomos politênicos em todas as espécies analisadas devido à adesão de micronucléolos em regiões específicas dos cromossomos. Os micronucléolos são estruturas arredondadas que contêm, provavelmente, DNA extracromossômico transcricionalmente ativo. Em T. pubescens, o rDNA está predominantemente localizado nas secções cromossômicas X-10 e X-8. Em R. americana o rDNA está freqüentemente associado à heterocromatina centromérica dos cromossomos X, C, B e A, e também às secções X-1 e B-13. Sondas ribossômicas em R. milleri hibridaram, em alta freqüência, em regiões teloméricas e pericêntricas de cromossomos politênicos. Schwenkfeldina sp. apresenta uma distribuição incomum do rDNA em núcleos politênicos, caracterizada pela adesão de micronucléolos em muitas regiões cromossômicas. Os resultados mostraram que os micronucléolos estão preferencialmente associados à heterocromatina intercalar ou terminal de todos os sciarídeos analisados e, dependendo da espécie, estão aderidos a um número pequeno (Trichosia), moderado (Rhynchosciara) e grande (Schwenkfeldina sp.) de sítios em cromossomos politênicos. Este trabalho também descreve a caracterização de seqüências presentes nas extremidades cromossômicas de R. americana, que se iniciou através da triagem de uma microbiblioteca plasmidial, feita a partir de uma extremidade microdissecada B-1. Uma repetição do tipo satélite foi identificada e sua composição de bases, estrutura genômica e localização cromossômica são semelhantes às repetições teloméricas complexas de Nematocera que já foram descritas. Contudo, dados obtidos em outras espécies de Rhynchosciara, assim como a localização desse satélite e da transcriptase reversa, sugerem que o elemento repetitivo caracterizado neste trabalho não atinge as extremidades dos cromossomos. A caracterização de seqüências terminais e subterminais presentes nos cromossomos de R. americana foi continuada através da triagem de uma biblioteca de DNA desse díptero clonada em fagos Dash. Escolhemos como sonda para a triagem o clone pRaM47.33, representativo do elemento repetitivo M22, caracterizado em R. americana. Foram analisados cerca de 12kb de um único inserto de fago, que continha, alem das repetições M22, uma nova repetição de 16pb, organizada em tandem e que denominamos de M16. Resultados de hibridações in situ revelaram a presença da repetição M16 nas 5 extremidades cromossômicas não-telocêntricas de R. americana. Essa repetição também foi utilizada como sonda em uma outra triagem da mesma biblioteca genômica, o que permitiu a seleção e análise de aproximadamente 50kb de DNA cromossômico terminal de R. americana. Encontramos também, ao longo dessas 50kb de DNA analisado, repetições de 414pb anteriormente caracterizadas em R. americana; parte de seqüências do transposon Ramar1 e do retrotransposon RaTART . Além disso, foram observadas também seqüências que não apresentam semelhança significativa com seqüências depositadas no banco de dados GenBank, e que tampouco apresentam motivos repetitivos. Os resultados obtidos apontam para a possibilidade de que a região telomérica de R. americana seja composta por mais de um tipo de elemento repetitivo. / The chromosomal localization of ribosomal DNA (rDNA) was studied in polytene and diploid tissues of four sciarid species, Trichosia pubescens, Rhynchosciara americana, R. milleri and Schwenkfeldina sp. While hybridization to mitotic chromosomes showed the existence of a single rDNA locus, ribosomal probes hybridized to more than one polytene chromosome region in all the species analyzed as a result of micronucleolar attachment to specific chromosome sites. Micronucleoli are small, round bodies containing transcriptionally active, probably extrachromosomal rDNA. In T. pubescens the rDNA is predominantly localized in chromosome sections X-10 and X-8. In R. americana the rDNA is frequently found associated with centromeric heterochromatin of the chromosomes X, C, B and A, and also with sections X-1 and B-13. Ribosomal probes in R. milleri hybridized with high frequency to pericentric and telomeric regions of its polytene complement. Schwfenkfeldina sp. displays a remarkably unusual distribution of rDNA in polytene nuclei, characterized by the attachment of micronucleoli to many chromosome regions. The results showed that micronucleoli preferentially associate with intercalary or terminal heterochromatin of all sciarid flies analyzed and, depending on the species, are attached to a few (Trichosia), moderate (Rhynchosciara) or a large (Schwenkfeldina sp.) number of polytene chromosome sites. This work also describes the characterization of chromosome end sequences of Rhynchosciara americana, initiated with the screening of a plasmid microlibrary made from a microdissected polytene chromosome end. We report the identification and sequencing of an R. americana satellite displaying base composition, genomic structure and chromosomal localization similar to the complex telomeric repeats of Nematocera that have previously been characterized. However, data obtained in other Rhynchosciara species, as well as distinct chromosomal localization of satellite and reverse transcriptase loci in R. americana, suggest that the repetitive element characterized does not reach the very end of the chromosome. The characterization of chromosome end sequences of Rhynchosciara americana continued with the screening of a phage library made with its genomic DNA. We choose pRaM47.33, a clone whose insert is a repetitive microsatellite characterized in the subtelomeric region of R. americana chromosomes, as a probe for the screening. We analyzed 12kb of a single phage insert, composed of M22 tandem arrays and a new microsatellite which was 16pb long, arranged in tandem (named M16). In situ hybridization showed the presence of M16 repeats in the five telomeric termini of R. americana chromosomes. The M16 repeat was used as a probe in another screen of the same phage library, which allowed us to analyze approximately 50kb of terminal DNA. We find that repetitive sequences, such as the 414pb repeat previously characterized in R. americana and stretches of Ramar1 and RaTART mobile elements, also characterized in R. americana, compose the subtelomeric region of R. americana chromosomes. Additionally, we find sequences that do not match sequences in the GenBank database and do not present repetitive motifs. Our results suggest that the telomeric regions of R. americana chromosomes are composed of more than one type of repetitive sequence.

LITERATURE REVIEW: A systematic review of the associations between effortful control, repetitive negative thinking and depression in adolescence. ABSTRACT: Background: Repetitive negative thinking (RNT) and the self-regulatory temperament, effortful control (EC), have been found to be important risk factors for the development of depressive symptoms. Furthermore, adolescence has been found to be a period of increased risk for developing depressive symptoms. The relationships between these risk pathways are not well understood during this period of development. Objective: This systematic review aimed to evaluate the literature exploring the relationships RNT and EC have in accounting for depressive symptoms in adolescents. In particular, whether RNT and EC are associated with depressive symptoms, and whether EC moderates the effects of RNT on depressive symptoms. Methods: Three databases and key journals were searched for studies measuring EC, RNT and depressive symptoms in 10-20 year olds. Study selection was undertaken by applying inclusion and exclusion criteria. The methodological quality of the included studies was assessed using a validated checklist. Inter-rater reliability was calculated for a random subsample of the search. Results: Thirteen studies were selected for inclusion. There was evidence indicating that RNT was correlated with depressive symptoms both concurrently and prospectively. The evidence for a relationship between lower EC and higher levels of depressive symptoms was mixed. High quality studies concluded that EC and depressive symptoms are associated concurrently, but not over time. There is evidence that lower EC predicts RNT over time, and even spanning over childhood. Some evidence was found for EC as a moderator between RNT and depressive symptoms and this was also found when the relationship was prospective. Conclusions: Whilst the reviewed literature had many strengths, there were large differences in how EC in particular, was measured. This resulted in a challenge synthesising the results and making clear conclusions. Future research would benefit from considering self-report and behavioural measures, and recognising the potential impact of stressful life events. EMPIRICAL PAPER: Investigating associations between repetitive negative thinking, stress, and effortful control, and the development and maintenance of depression in adolescence: A follow-up study. ABSTRACT: Background: Adolescence is a period of increased vulnerability for depressive symptoms (Twenge & Nolen-Hoeksema, 2002). Given the impact of emotional disorders on an individual, it is important to understand risk factors, and conversely, protective factors to inform effective interventions. Repetitive negative thinking (RNT) and the self-regulatory temperament, effortful control (EC), have been found to be important risk factors for the development of depressive symptoms and require further exploration in adolescence. Objective: This study investigated whether RNT predicted changes in later depressive symptoms, and if so, whether this change was moderated by EC. The study examined these associations during emotional reactivity to a stressor (exams), and emotional recovery following the stressor. Methods: Two samples with similar designs and measures were combined in this study. Two-hundred-and-fifty-five females completed Baseline questionnaires measuring life events, RNT, EC, and depressive symptoms. One-hundred-and-ninety-nine participants were followed up prior to their exams (Pre-exam), and 115 participants were followed up after their exams (Post-exam). Results: The study first examined emotional reactivity to stress, finding that contrary to the literature, RNT did not predict depressive symptoms in response to stress, when controlling for Baseline depressive symptoms. EC did not significantly interact with RNT in predicting depressive symptoms. However, RNT was associated with emotional recovery from stress: RNT predicted levels of depressive symptoms following exams, when controlling for Pre-exam depressive symptoms. Furthermore, EC moderated this relationship, however contrary to the literature and predictions, this was not in the expected direction, with high levels of EC associated with high levels of depressive symptoms. Conclusions: These findings suggest that despite the strengths of the study design, including a large sample at Baseline and follow up over a period of stress, hypothesized associations were not found during emotional reactivity to stress, but hypothesized associations were found during emotional recovery from stress. Recommendations are made for future studies, including recruiting sufficient number of males to the study.

Repetitive questioning is due to an impaired episodic memory and is a frequent, often presenting, problem in patients with Alzheimer’s disease (amnestic type). It is due to the patients’ difficulties learning new information, retaining it, and recalling it, and is often aggravated by a poor attention span and easy distractibility. A number of factors may trigger and maintain repetitive questioning. Caregivers should try to identify and address these triggers. In the case discussion presented, it is due to the patient’s concerns about her and her family’s safety triggered by watching a particularly violent movie aired on TV. What went wrong in the patient/caregiver interaction and how it could have been avoided or averted are explored. Also reviewed are the impact of repetitive questioning, the challenges it raises for caregivers, and some effective intervention strategies that may be useful to diffuse the angst that caregivers experience with repetitive questioning.

Criticism of discrete classification systems for mental disorders has led to a focus on identification of mechanisms that cut across symptom clusters, known as transdiagnostic factors. One such proposed factor is negative repetitive thought (NRT), or a perseverative, often uncontrollable, focus on negative information, experiences, or expectations. Worry and rumination are two major constructs thought to compose NRT. No confirmatory factor analyses have investigated whether worry and rumination might compose a general NRT factor, discrete factors, or some combination of the two. The first purpose of the current study was to use confirmatory factor analyses to uncover whether worry and rumination are best characterized as separate or common constructs. In addition to this purpose, the study investigated NRT as a transdiagnostic factor for psychopathology. Finally, it examined incremental associations of NRT with mental illness symptoms, after controlling for negative emotionality, the most well established transdiagnostic risk factor. A bi-factor conceptualization of worry and rumination, in which there was a common NRT factor and specific worry and rumination factors, yielded the best fit to the data across three separate samples. The NRT factor was associated with both internalizing and externalizing psychopathology; however, it demonstrated significant overlap with negative emotionality. Further exploration of this overlap using bi-factor modeling demonstrated that NRT and negative emotionality are likely best thought of as a unidimensional general negative affect construct, and this structure was replicated across samples. Importantly, evidence was found that this tendency to experience negative affect was also a common liability for mental illness symptoms.

In a roll-to-roll web system lateral motion of a web caused by disturbances, which are often periodic, results in poor product quality. To reduce the effect of such disturbances, two control strategies are applied. First, the internal model principle is used to reject a sinusoidal disturbance. Second, repetitive control theory is used to reject a general periodic disturbance. We provide the synthesis procedure for both strategies, and demonstrate its use in several simulation studies on a five-roller web system. The simulation results show that the effect of disturbances, either sinusoidal or triangular, on lateral motion are significantly reduced with the internal model controller or the modified repetitive controller.