664 research outputs found

    A Kymograph and Its Use

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    The science of physiology in its present condition owes much of its advancement to the skillful manipulation of cunningly devised apparatus. Without the successful invention of delicate mechanical appliances many of the profound researches of Foster, Du Bois, Raymond, McKendrick, Martin and others would never have been possible. It must be granted, however, that invention and skill in manipulation have been supplemented by clear and comprehensive interpretation of results obtained, and it is to the latter that most credit is due. In emphasizing the value of scientific apparatus and its use, we recognize the imperative need of a fundamental knowledge in anatomy, histology, chemistry and physics, which the pupil must necessarily possess before entering upon advanced work in the science of physiology. It is true that the general student versed in these branches may secure a fair working knowledge of physiology simply from a good text, supplemented by ample anatomical demonstrations, complete diagrams and charts. But far more comprehensive will his views of the science be if a well-chosen list of experiments be worked by his own hand in a fully equipped physiological laboratory

    The Johns Hopkins Biological Laboratory

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    For the past fifteen years it has been customary for the members of the biological department of Johns Hopkins University to devote their summer vacations to pursuing their studies upon the sea shore, where living marine animal forms may be secured for daily use

    How should we measure psychological resilience in sport performers?

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    Psychological resilience is important in sport because athletes must constantly withstand a wide range of pressures to attain and sustain high performance. To advance psychologists’ understanding of this area, there exists an urgent need to develop a sport-specific measure of resilience. The purpose of this paper is to review psychometric issues in resilience research and to discuss the implications for sport psychology. Drawing on the wider general psychology literature to inform the discussion, the narrative is divided into three main sections relating to resilience and its assessment: adversity, positive adaptation, and protective factors. The first section reviews the different ways that adversity has been measured and considers the potential problems of using items with varying degrees of controllability and risk. The second section discusses the different approaches to assessing positive adaptation and examines the issue of circularity pervasive in resilience research. The final section explores the various issues related to the assessment of protective factors drawing directly from current measures of resilience in other psychology sub-disciplines. The commentary concludes with key recommendations for sport psychology researchers seeking to develop a measure of psychological resilience in athletes

    Ultradian Cortisol Pulsatility Encodes a Distinct, Biologically Important Signal

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    Cortisol is released in ultradian pulses. The biological relevance of the resulting fluctuating cortisol concentration has not been explored.Determination of the biological consequences of ultradian cortisol pulsatility.A novel flow through cell culture system was developed to deliver ultradian pulsed or continuous cortisol to cells. The effects of cortisol dynamics on cell proliferation and survival, and on gene expression were determined. In addition, effects on glucocorticoid receptor (GR) expression levels and phosphorylation, as a potential mediator, were measured.Pulsatile cortisol caused a significant reduction in cell survival compared to continuous exposure of the same cumulative dose, due to increased apoptosis. Comprehensive analysis of the transcriptome response by microarray identified genes with a differential response to pulsatile versus continuous glucocorticoid delivery. These were confirmed with qRT-PCR. Several transcription factor binding sites were enriched in these differentially regulated target genes, including CCAAT-displacement protein (CDP). A CDP regulated reporter gene (MMTV-luc) was, as predicted, also differentially regulated by pulsatile compared to continuous cortisol delivery. Importantly there was no effect of cortisol delivery kinetics on either GR expression, or activation (GR phosphoSer(211)).Cortisol oscillations exert important effects on target cell gene expression, and phenotype. This is not due to differences in cumulative cortisol exposure, or either expression, or activation of the GR. This suggests a novel means to regulate GR function

    The Moderating Effects of Peer and Parental Support on the Relationship Between Vicarious Victimization and Substance Use

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    General strain theory (GST) hypothesizes that youth are more likely to engage in delinquency when they experience vicarious victimization, defined as knowing about or witnessing violence perpetrated against others, but that this relationship may be attenuated for those who receive social support from significant others. Based on prospective data from youth aged 8 to 17 participating in the Project on Human Development in Chicago Neighborhoods (PHDCN), this article found mixed support for these hypotheses. Controlling for prior involvement in delinquency, as well as other risk and protective factors, adolescents who reported more vicarious victimization had an increased likelihood of alcohol use in the short term, but not the long term, and victimization was not related to tobacco or marijuana use. Peer support did not moderate the relationship between vicarious victimization and substance use, but family support did. In contrast to strain theory’s predictions, the relationship between vicarious victimization and substance use was stronger for those who had higher compared with lower levels of family support. Implications of these findings for strain theory and future research are discussed

    Mindfulness in schools: a health promotion approach to improving adolescent mental health.

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    Between 10 and 20% of adolescents worldwide experience a mental health problem within a given 12-month period. Mental health problems impact on an adolescent’s potential to live a fulfilling and productive life and lead to challenges such as stigma, isolation and discrimination. To address this need, in recent years, there has been growing interest into broad-based school-integrated health promotion interventions that seek to build resilience and augment protective factors in adolescents. Mindfulness-based interventions (MBIs) reflect one such approach that have been administered to adolescent populations in both resilience building and treatment contexts. This paper discusses the utility of school-based MBIs as an adolescent health promotion approach and makes recommendations for intervention design, delivery and evaluation. Emerging evidence indicates that school-integrated MBIs may be a cost-effective means of not only meeting government objectives relating to adolescent mental health, but also for improving the wellbeing of teachers and parents. Furthermore, there is growing evidence indicating that mindfulness can elicit improvements in student learning performance and general classroom behaviour. However, notwithstanding these beneficial properties, there remains a need to conduct large-scale empirical investigations that seek to evaluate the effectiveness of school-integrated MBIs at a regional or national level. A further challenge is the need to ensure that mindfulness instructors are able to impart to adolescents an experiential understanding of this ancient contemplative technique.N

    The meaning of actualization of self-care resources among a group of older home-dwelling people—A hermeneutic study

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    Self-care is an activity of mature persons who have developed their abilities to take care of themselves. Individuals can choose to actualize their self-care abilities into self-care activities to maintain, restore, or improve health and well-being. It is of importance to understand the meaning of the actualization of self-care resources among older people. The aim of this study was to investigate the meaning of the actualization of self-care resources, i.e., actions taken to improve, maintain, or restore health and well-being, among a group of older home-dwelling individuals with a high sense of coherence. The design of this study was to reanalyse narratives revealing self-care activities from 11 (five females and six males) Norwegian older home-dwelling people (65 years or older) identified as having a high sense of coherence. In order to reveal the meaning and get an understanding of why these self-care resources were realized or actualized, a Gadamerian-based research method was chosen. The analysis revealed four themes that showed the meaning of actualization of self-care resources in the study group: “Desire to carry on”, “Be of use to others”, “Self-realization”, and “Confidence to manage in the future”. The findings showed what older people found meaningful to strive for, and this information can be used as a guide for health professionals when supporting older people in their self-care. Older people with self-care resources can also be an important resource for others in need of social contact and practical help. These resources have to be asked for in voluntary work among older people in need of help and, thereby, can be a valuable supplement to the community health care system

    Enriching for correct prediction of biological processes using a combination of diverse classifiers

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    <p>Abstract</p> <p>Background</p> <p>Machine learning models (classifiers) for classifying genes to biological processes each have their own unique characteristics in what genes can be classified and to what biological processes. No single learning model is qualitatively superior to any other model and overall precision for each model tends to be low. The classification results for each classifier can be complementary and synergistic suggesting the benefit of a combination of algorithms, but often the prediction probability outputs of various learning models are neither comparable nor compatible for combining. A means to compare outputs regardless of the model and data used and combine the results into an improved comprehensive model is needed.</p> <p>Results</p> <p>Gene expression patterns from NCI's panel of 60 cell lines were used to train a Random Forest, a Support Vector Machine and a Neural Network model, plus two over-sampled models for classifying genes to biological processes. Each model produced unique characteristics in the classification results. We introduce the Precision Index measure (PIN) from the maximum posterior probability that allows assessing, comparing and combining multiple classifiers. The class specific precision measure (PIC) is introduced and used to select a subset of predictions across all classes and all classifiers with high precision. We developed a single classifier that combines the PINs from these five models in prediction and found that the PIN Combined Classifier (PINCom) significantly increased the number of correctly predicted genes over any single classifier. The PINCom applied to test genes that were not used in training also showed substantial improvement over any single model.</p> <p>Conclusions</p> <p>This paper introduces novel and effective ways of assessing predictions by their precision and recall plus a method that combines several machine learning models and capitalizes on synergy and complementation in class selection, resulting in higher precision and recall. Different machine learning models yielded incongruent results each of which were successfully combined into one superior model using the PIN measure we developed. Validation of the boosted predictions for gene functions showed the genes to be accurately predicted.</p

    Timing Is Critical for Effective Glucocorticoid Receptor Mediated Repression of the cAMP-Induced CRH Gene

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    Glucocorticoid negative feedback of the hypothalamus-pituitary-adrenal axis is mediated in part by direct repression of gene transcription in glucocorticoid receptor (GR) expressing cells. We have investigated the cross talk between the two main signaling pathways involved in activation and repression of corticotrophin releasing hormone (CRH) mRNA expression: cyclic AMP (cAMP) and GR. We report that in the At-T20 cell-line the glucocorticoid-mediated repression of the cAMP-induced human CRH proximal promoter activity depends on the relative timing of activation of both signaling pathways. Activation of the GR prior to or in conjunction with cAMP signaling results in an effective repression of the cAMP-induced transcription of the CRH gene. In contrast, activation of the GR 10 minutes after onset of cAMP treatment, results in a significant loss of GR-mediated repression. In addition, translocation of ligand-activated GR to the nucleus was found as early as 10 minutes after glucocorticoid treatment. Interestingly, while both signaling cascades counteract each other on the CRH proximal promoter, they synergize on a synthetic promoter containing ‘positive’ response elements. Since the order of activation of both signaling pathways may vary considerably in vivo, we conclude that a critical time-window exists for effective repression of the CRH gene by glucocorticoids

    Refining trait resilience: identifying engineering, ecological, and adaptive facets from extant measures of resilience

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    The current paper presents a new measure of trait resilience derived from three common mechanisms identified in ecological theory: Engineering, Ecological and Adaptive (EEA) resilience. Exploratory and confirmatory factor analyses of five existing resilience scales suggest that the three trait resilience facets emerge, and can be reduced to a 12-item scale. The conceptualization and value of EEA resilience within the wider trait and well-being psychology is illustrated in terms of differing relationships with adaptive expressions of the traits of the five-factor personality model and the contribution to well-being after controlling for personality and coping, or over time. The current findings suggest that EEA resilience is a useful and parsimonious model and measure of trait resilience that can readily be placed within wider trait psychology and that is found to contribute to individual well-bein
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