937 resultados para Quantitative structure-activity relationship


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Este estudo apresenta uma relação entre o trabalho agrícola familiar e a saúde humana e ambiental em um cenário insular com características rurais, tendo-se como objetivo geral, analisar a sustentabilidade da relação socioambiental do trabalho de agricultores moradores da Ilha dos Marinheiros. Os objetivos específicos foram: Caracterizar a sustentabilidade do trabalho agrícola familiar na Ilha dos Marinheiros; Identificar como os trabalhadores agricultores da Ilha dos Marinheiros significam a sua saúde e atuam para mantê-la; Compreender como os trabalhadores agricultores identificam os impactos positivos e negativos do trabalho agrícola familiar desencadeados no ambiente e a conservação da saúde ambiental. Trata-se de uma pesquisa exploratória, descritiva, transversal com desenho de método misto com estruturação [QUAL + quan]. Foi realizada na Ilha dos Marinheiros, Rio Grande, Brasil, com 129 trabalhadores agricultores entre março a outubro de 2013, utilizando-se entrevista com aplicação individual de um questionário semiestruturado, gravado, previamente elaborado e testado. Também foram utilizados dados secundários referentes à constituição geográfica, cultural e econômica da Ilha. A organização dos dados qualitativos ocorreu a partir da transcrição dos dados oriundos das entrevistas no Microsoft Word, seguido da Análise de Conteúdo por temas com auxílio do Software Nvivo10. Para ambos os processos de análise utilizou-se o apoio teórico na racionalidade cultural de Enrique Leff. A organização dos dados quantitativos se fez pela codificação dos dados e digitação no software Statistical Package for the Social Sciences, 21.0, seguido da análise estatística descritiva e Teste Qui-quadrado de Pearson, com o p-valor <0,05 como significância estatística. Foram asseguradas as exigências éticas e científicas preconizadas nas pesquisas com seres humanos, mediante Resolução 466/2012 e aprovação do macroprojeto pelo Comitê de Ética da Universidade Federal do Rio Grande sob parecer 026/2013. Teve-se 78 trabalhadores agricultores do sexo masculino com idade média de (55,33±14,27), e 51 do sexo feminino, com idade média de (54,68±11,08). Predominou a descendência portuguesa 106 (84,8%), a maioria 100 (77,52%) com ensino fundamental incompleto, média de 2,53 integrantes no domicílio e renda familiar média de (1.648,39±947,72) para uma média de 2,58 dependentes desta. Os participantes atuavam em média há 40,56 anos, por (8,51± 3,10) horas diárias de trabalho em suas propriedades com média de 12,49 hectares. A atividade que mais exerciam e que eram mais auxiliados foi colher os produtos agrícolas, predominando o sexo masculino nesta função. O desenvolvimento do trabalho era conduzido mais pelos homens e de forma diária 83 (64,34%), seguido dos filhos 33 (25,58%) também diariamente 24 (18,60%). Quanto à saúde humana, esta foi concebida como boa, regular e ruim, com ações que convergem à continuidade do exercício laboral e adesão aos serviços de saúde mínima anualmente. Já os impactos positivos do trabalho no ambiente incidiram na conservação do trabalho como uma riqueza, o que exige atenção quanto ao uso dos agrotóxicos frente aos impactos negativos desencadeados ao ambiente em uma perspectiva sustentável à vida humana e não humana. O estudo fornece subsídios 6 contributivos à prática argumentativa do Enfermeiro à saúde ocupacional na agricultura familiar sob uma perspectiva sustentável ao ambiente.

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Breast milk is regarded as an ideal source of nutrients for the growth and development of neonates, but it can also be a potential source of pollutants. Mothers can be exposed to different contaminants as a result of their lifestyle and environmental pollution. Mercury (Hg) and arsenic (As) could adversely affect the development of fetal and neonatal nervous system. Some fish and shellfish are rich in selenium (Se), an essential trace element that forms part of several enzymes related to the detoxification process, including glutathione S-transferase (GST). The goal of this study was to determine the interaction between Hg, As and Se and analyze its effect on the activity of GST in breast milk. Milk samples were collected from women between day 7 and 10 postpartum. The GST activity was determined spectrophotometrically; total Hg, As and Se concentrations were measured by atomic absorption spectrometry. To explain the possible association of Hg, As and Se concentrations with GST activity in breast milk, generalized linear models were constructed. The model explained 44% of the GST activity measured in breast milk. The GLM suggests that GST activity was positively correlated with Hg, As and Se concentrations. The activity of the enzyme was also explained by the frequency of consumption of marine fish and shellfish in the diet of the breastfeeding women.

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The Water Framework Directive (WFD) establishes Environmental Quality Standards (EQS) in marine water for 34 priority substances. Among these substances, 25 are hydrophobic and bioaccumulable (2 metals and 23 organic compounds). For these 25 substances, monitoring in water matrix is not appropriate and an alternative matrix should be developed. Bivalve mollusks, particularly mussels (Mytilus edulis, Mytilus galloprovincialis), are used by Ifremer as a quantitative biological indicator since 1979 in France, to assess the marine water quality. This study has been carried out in order to determine thresholds in mussels at least as protective as EQS in marine water laid down by the WFD. Three steps are defined: - Provide an overview of knowledges about the relations between the concentrations of contaminants in the marine water and mussels through bioaccumulation factor (BAF) and bioconcentration factor (BCF). This allows to examine how a BCF or a BAF can be determined: BCF can be determined experimentally (according to US EPA or ASTM standards), or by Quantitative Activity-Structure Relationship models (QSAR): four equations can be used for mussels. BAF can be determined by field experiment; but none standards exists. It could be determined by using QSAR but this method is considered as invalid for mussels, or by using existing model: Dynamic Budget Model, but this is complex to use. - Collect concentrations data in marine water (Cwater) in bibliography for those 25 substances; and compare them with concentration in mussels (Cmussels) obtained through French monitoring network of chemicals contaminants (ROCCH) and biological integrator network RINBIO. According to available data, this leads to determine the BAF or the BCF (Cmussels /Cwater) with field data. - Compare BAF and BCF values (when available) obtained with various methods for these substances: BCF (stemming from the bibliography, using experimental process), BCF calculated by QSAR and BAF determined using field data. This study points out that experimental BCF data are available for 3 substances (Chlorpyrifos, HCH, Pentachlorobenzene). BCF by QSAR can be calculated for 20 substances. The use of field data allows to evaluate 4 BAF for organic compounds and 2 BAF for metals. Using these BAF or BCF value, thresholds in shellfish can be determined as an alternative to EQS in marine water.

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In this work metal - Microwave Plasma CVD diamond Schottky devices were studied. The current density vs. applied voltage reveals rectification ratios up to 10(4) at \ +/- 2V \. Under illumination an inversion and increase of the rectification is observed. The carrier density is 10(15) cm(-3) and the ideality factors near 1.5. The dark current vs. temperature shows that below 150 K the bulk transport is controlled by a hopping process with a density of defects of 10(16) cm(-3). For higher temperatures an extrinsic ionisation with activation energy of 0.3 eV takes place. The correlation with the polycrystalline nature of the samples is focused.

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In this work metal - Microwave Plasma CVD diamond Schottky devices were studied. The current density vs. applied voltage reveals rectification ratios up to 10(4) at \ +/- 2V \. Under illumination an inversion and increase of the rectification is observed. The carrier density is 10(15) cm(-3) and the ideality factors near 1.5. The dark current vs. temperature shows that below 150 K the bulk transport is controlled by a hopping process with a density of defects of 10(16) cm(-3). For higher temperatures an extrinsic ionisation with activation energy of 0.3 eV takes place. The correlation with the polycrystalline nature of the samples is focused.

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The purpose of this study was to examine the relationship between the structure of jobs and burnout, and to assess to what extent, if any this relationship was moderated by individual coping methods. This study was supported by the Karasek's (1998) Job Demand-Control-Support theory of work stress as well as Maslach and Leiter's (1993) theory of burnout. Coping was examined as a moderator based on the conceptualization of Lazarus and Folkman (1984). Two overall overarching questions framed this study: (a) what is the relationship between job structure, as operationalized by job title, and burnout across different occupations in support services in a large municipal school district? and (b) To what extent do individual differences in coping methods moderate this relationship? This study was a cross-sectional study of county public school bus drivers, bus aides, mechanics, and clerical workers (N = 253) at three bus depot locations within the same district using validated survey instruments for data collection. Hypotheses were tested using simultaneous regression analyses. Findings indicated that there were statistically significant and relevant relationships among the variables of interest; job demands, job control, burnout, and ways of coping. There was a relationship between job title and physical job demands. There was no evidence to support a relationship between job title and psychological demands. Furthermore, there was a relationship between physical demands, emotional exhaustion and personal accomplishment; key indicators of burnout. Results showed significant correlations between individual ways of coping as a moderator between job structure, operationalized by job title, and individual employee burnout adding empirical evidence to the occupational stress literature. Based on the findings, there are implications for theory, research, and practice. For theory and research, the findings suggest the importance of incorporating transactional models in the study of occupational stress. In the area of practice, the findings highlight the importance of enriching jobs, increasing job control, and providing individual-level training related to stress reduction.

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Thesis (Ph.D, Kinesiology & Health Studies) -- Queen's University, 2016-07-21 14:22:50.954

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Thesis (Ph.D, Education) -- Queen's University, 2016-09-22 22:05:24.246

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Minimal research has explored what comprises a quality physical activity (PA) participation experience, particularly among military Veterans with a physical disability for whom evidence of the benefits of PA is growing. To address this research gap, this dissertation examines quality PA participation among military Veterans with a physical disability. Manuscript 1 explores the views of Veterans with a physical disability regarding what elements constitute a quality PA experience, and how these elements may be fostered. Eighteen Veterans with various physical disabilities and PA experiences participated in interviews. Four quality elements were identified via thematic analysis: group cohesion, challenge, having a role, and independence and choice. A further three factors (the physical and social environments, and program structure) were identified as precursors for a quality experience. Manuscript 2 explores how PA programs for Veterans with a physical disability are delivered, and how these delivery strategies link conceptually to quality participation. Interviews were conducted with program staff from three PA programs for Veterans, and program documentation collected, to develop an understanding of program delivery strategies. Four strategies with potential links to quality participation were identified through thematic analysis: foster social connections, challenge participants, tailor programs and outcomes to match participant needs, and include knowledgeable coaches and instructors. Manuscript 3 evaluates the participation of Veterans with functional impairments in PA events, and examines the relationships among quality precursors, quality elements, and participation outcomes. Results indicate that program participation did not promote long-term increases in PA indicators. However, an indicator of the quality element belongingness mediated the relationship at particular time-points between coach interpersonal skills and three participation outcomes: family integration, PA intentions, and PA planning. These findings suggest that a quality participation experience created by coaches may positively impact the transition to civilian life, and promote efforts to engage in ongoing PA. Overall, this dissertation contributes towards a greater depth in understanding of the experiences of Veterans with a physical disability in PA programs. The findings begin to provide a foundation for researchers and practitioners aiming to create, deliver, and promote quality PA interventions and programming for Veterans with a physical disability.

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Background and Study Rationale Being physically active is a major contributor to both physical and mental health. More specifically, being physically active lowers risk of coronary heart disease, high blood pressure, stroke, metabolic syndrome (MetS), diabetes, certain cancers and depression, and increases cognitive function and wellbeing. The physiological mechanisms that occur in response to physical activity and the impact of total physical activity and sedentary behaviour on cardiometabolic health have been extensively studied. In contrast, limited data evaluating the specific effects of daily and weekly patterns of physical behaviour on cardiometabolic health exist. Additionally, no other study has examined interrelated patterns and minute-by-minute accumulation of physical behaviour throughout the day across week days in middle-aged adults. Study Aims The overarching aims of this thesis are firstly to describe patterns of behaviour throughout the day and week, and secondly to explore associations between these patterns and cardiometabolic health in a middle-aged population. The specific objectives are to: 1 Compare agreement between the International Physical Activity Questionnaire-Short Form (IPAQ-SF) and GENEActiv accelerometer-derived moderate-to-vigorous (MVPA) activity and secondly to compare their associations with a range of cardiometabolic and inflammatory markers in middle-aged adults. 2 Determine a suitable monitoring frame needed to reliably capture weekly, accelerometer-measured, activity in our population. 3 Identify groups of participants who have similar weekly patterns of physical behaviour, and determine if underlying patterns of cardiometabolic profiles exist among these groups. 4 Explore the variation of physical behaviour throughout the day to identify whether daily patterns of physical behaviour vary by cardiometabolic health. Methods All results in this thesis are based on data from a subsample of the Mitchelstown Cohort; 475 (46.1% males; mean aged 59.7±5.5 years) middle-aged Irish adults. Subjective physical activity levels were assessed using the IPAQ-SF. Participants wore the wrist GENEActiv accelerometer for 7 consecutive days. Data was collected at 100Hz and summarised into a signal magnitude vector using 60s epochs. Each time interval was categorised based on validated cut-offs. Data on cardiometabolic and inflammatory markers was collected according to standard protocol. Cardiometabolic outcomes (obesity, diabetes, hypertension and MetS) were defined according to internationally recognised definitions by World Health Organisation (WHO) and Irish Diabetes Federation (IDF). Results The results of the first chapter suggest that the IPAQ-SF lacks the sensitivity to assess patterning of activity and guideline adherence and assessing the relationship with cardiometabolic and inflammatory markers. Furthermore, GENEActiv accelerometer-derived MVPA appears to be better at detecting relationships with cardiometabolic and inflammatory markers. The second chapter examined variations in day-to-day physical behaviour levels between- and within-subjects. The main findings were that Sunday differed from all other days in the week for sedentary behaviour and light activity and that a large within-subject variation across days of the week for vigorous activity exists. Our data indicate that six days of monitoring, four weekdays plus Saturday and Sunday, are required to reliably estimate weekly habitual activity in all activity intensities. In the next chapter, latent profile analysis of weekly, interrelated patterns of physical behaviour identified four distinct physical behaviour patterns; Sedentary Group (15.9%), Sedentary; Lower Activity Group (28%), Sedentary; Higher Activity Group (44.2%) and a Physically Active Group (11.9%). Overall the Sedentary Group had poorer outcomes, characterised by unfavourable cardiometabolic and inflammatory profiles. The remaining classes were characterised by healthier cardiometabolic profiles with lower sedentary behaviour levels. The final chapter, which aimed to compare daily cumulative patterns of minute-by-minute physical behaviour intensities across those with and without MetS, revealed significant differences in weekday and weekend day MVPA. In particular, those with MetS start accumulating MVPA later in the day and for a shorted day period. Conclusion In conclusion, the results of this thesis add to the evidence base regards an optimal monitoring period for physical behaviour measurement to accurately capture weekly physical behaviour patterns. In addition, the results highlight whether weekly and daily distribution of activity is associated with cardiometabolic health and inflammatory profiles. The key findings of this thesis demonstrate the importance of daily and weekly physical behaviour patterning of activity intensity in the context of cardiometabolic health risk. In addition, these findings highlight the importance of using physical behaviour patterns of free-living adults observed in a population-based study to inform and aid health promotion activity programmes and primary care prevention and treatment strategies and development of future tailored physical activity based interventions.

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Este artículo presenta los resultados de una investigación realizada al interior de dos contextos. Por un lado, el teórico, en el marco de uno de los discursos más relevantes en los campos de la estrategia organizacional, de la managerial and organizational cognition (MOC) y, en general, de los estudios organizacionales (organization studies): la construcción de sentido (sensemaking). Por el otro, el empírico, en una de las grandes compañías multinacionales del sector automotriz con presencia global. Esta corporación enfrenta una permanente tensión entre lo que dicta la casa matriz, en relación con el cumplimiento de metas y estándares específicos, considerando el mundo entero, y los retos que, teniendo en cuenta lo regional y lo local, experimentan los altos directivos encargados de hacer prosperar la empresa en estos lugares. La aproximación implementada fue cualitativa. Esto en atención a la naturaleza de la problemática abordada y la tradición del campo. Los resultados permiten ampliar el actual nivel de comprensión acerca de los procesos de sensemaking de los altos directivos al enfrentar un entorno estratégico turbulento.

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Valproic acid (VPA) and trichostatin A (TSA) are known histone deacetylase inhibitors (HDACIs) with epigenetic activity that affect chromatin supra-organization, nuclear architecture, and cellular proliferation, particularly in tumor cells. In this study, chromatin remodeling with effects extending to heterochromatic areas was investigated by image analysis in non-transformed NIH 3T3 cells treated for different periods with different doses of VPA and TSA under conditions that indicated no loss of cell viability. Image analysis revealed chromatin decondensation that affected not only euchromatin but also heterochromatin, concomitant with a decreased activity of histone deacetylases and a general increase in histone H3 acetylation. Heterochromatin protein 1-α (HP1-α), identified immunocytochemically, was depleted from the pericentromeric heterochromatin following exposure to both HDACIs. Drastic changes affecting cell proliferation and micronucleation but not alteration in CCND2 expression and in ratios of Bcl-2/Bax expression and cell death occurred following a 48-h exposure of the NIH 3T3 cells particularly in response to higher doses of VPA. Our results demonstrated that even low doses of VPA (0.05 mM) and TSA (10 ng/ml) treatments for 1 h can affect chromatin structure, including that of the heterochromatin areas, in non-transformed cells. HP1-α depletion, probably related to histone demethylation at H3K9me3, in addition to the effect of VPA and TSA on histone H3 acetylation, is induced on NIH 3T3 cells. Despite these facts, alterations in cell proliferation and micronucleation, possibly depending on mitotic spindle defects, require a longer exposure to higher doses of VPA and TSA.