829 resultados para Social hypothesis testing


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Primary ciliary dyskinesia is a rare heterogeneous recessive genetic disorder of motile cilia, leading to chronic upper and lower respiratory symptoms. Prevalence is estimated at around 1:10,000, but many patients remain undiagnosed, while others receive the label incorrectly. Proper diagnosis is complicated by the fact that the key symptoms such as wet cough, chronic rhinitis and recurrent upper and lower respiratory infection, are common and nonspecific. There is no single gold standard test to diagnose PCD. Presently, the diagnosis is made by augmenting the medical history and physical examination with in patients with a compatible medical history following a demanding combination of tests including nasal nitric oxide, high- speed video microscopy, transmission electron microscopy, genetics, and ciliary culture. These tests are costly and need sophisticated equipment and experienced staff, restricting use to highly specialised centers. Therefore, it would be desirable to have a screening test for identifying those patients who should undergo detailed diagnostic testing. Three recent studies focused on potential screening tools: one paper assessed the validity of nasal nitric oxide for screening, and two studies developed new symptom-based screening tools. These simple tools are welcome, and hopefully remind physicians whom to refer for definitive testing. However, they have been developed in tertiary care settings, where 10 to 50% of tested patients have PCD. Sensitivity and specificity of the tools are reasonable, but positive and negative predictive values may be poor in primary or secondary care settings. While these studies take an important step forward towards an earlier diagnosis of PCD, more remains to be done before we have tools tailored to different health care settings.

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Diagnosis of primary ciliary dyskinesia (PCD) lacks a "gold standard" test and is therefore based on combinations of tests including nasal nitric oxide (nNO), high-speed video microscopy analysis (HSVMA), genotyping and transmission electron microscopy (TEM). There are few published data on the accuracy of this approach.Using prospectively collected data from 654 consecutive patients referred for PCD diagnostics we calculated sensitivity and specificity for individual and combination testing strategies. Not all patients underwent all tests.HSVMA had excellent sensitivity and specificity (100% and 93%, respectively). TEM was 100% specific, but 21% of PCD patients had normal ultrastructure. nNO (30 nL·min(-1) cut-off) had good sensitivity and specificity (91% and 96%, respectively). Simultaneous testing using HSVMA and TEM was 100% sensitive and 92% specific.In conclusion, combination testing was found to be a highly accurate approach for diagnosing PCD. HSVMA alone has excellent accuracy, but requires significant expertise, and repeated sampling or cell culture is often needed. TEM alone is specific but misses 21% of cases. nNO (≤30 nL·min(-1)) contributes well to the diagnostic process. In isolation nNO screening at this cut-off would miss ∼10% of cases, but in combination with HSVMA could reduce unnecessary further testing. Standardisation of testing between centres is a future priority.

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This paper integrates the literatures on the social value of lawsuits, the evolution of the law, and judicial preferences to evaluate the hypothesis that the law evolves toward efficiency. The setting is a simple accident model with costly litigation where the efficient law minimizes the sum of accident plus litigation costs. In the steady state equilibrium, the distribution of legal rules is not necessarily efficient but instead depends on a combination of selective litigation, judicial bias, and precedent.

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Deficits in social cognition are prominent symptoms of many human psychiatric disorders, but the origin of such deficits remains largely unknown. To further current knowledge regarding the neural network mediating social cognition, the present research program investigated the individual contributions of two temporal lobe structures, the amygdala and hippocampal formation, and one frontal lobe region, the orbital frontal cortex (Areas 11 and 13), to primate social cognition. Based on previous research, we hypothesized that the amygdala, hippocampal formation and orbital frontal cortex contribute significantly to the formation of new social relationships, but less to the maintenance of familiar ones. ^ Thirty-six male rhesus macaques (Macaca mulatta) served as subjects, and were divided into four experimental groups: Neurotoxic amygdala lesion (A-ibo, n = 9), neurotoxic or aspiration orbital frontal cortex lesion (O, n = 9), neurotoxic hippocampal formation lesion (H-ibo, n = 9) or sham-operated control (C, n = 9). Six social groups (tetrads) were created, each containing one member from each experimental group. The effect of lesion on established social relationships was assessed during pre- and post-surgical unrestrained social interactions, whereas the effect of lesion on the formation of new relationships was assessed during an additional phase of post-surgical testing with shuffled tetrad membership. Results indicated that these three neural structures each contribute significantly to both the formation and maintenance of social relationships. Furthermore, the amygdala appears to primarily mediate normal responses to threatening social signals, whereas the orbital frontal cortex plays a more global role in social cognition by mediating responses to both threatening and affiliative social signals. By contrast, the hippocampal formation seems to contribute to social cognition indirectly by providing access to previous experience during social judgments. ^ These conclusions were further investigated with three experiments that measured behavioral and physiological (stress hormone) reactivity to threatening stimuli, and three additional experiments that measured subjects' ability to flexibly alter behavioral responses depending on the incentive value of a food reinforcer. Data from these six experiments further confirmed and strengthened the three conclusions originating from the social behavior experiments and, when combined with the current literature, helped to formulate a simple, but testable, theoretical model of primate social cognition. ^

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Few studies have investigated causal pathways linking psychosocial factors to each other and to screening mammography. Conflicting hypotheses exist in the theoretic literature regarding the role and importance of subjective norms, a person's perceived social pressure to perform the behavior and his/her motivation to comply. The Theory of Reasoned Action (TRA) hypothesizes that subjective norms directly affect intention; while the Transtheoretical Model (TTM) hypothesizes that attitudes mediate the influence of subjective norms on stage of change. No one has examined which hypothesis best predicts the effect of subjective norms on mammography intention and stage of change. Two statistical methods are available for testing mediation, sequential regression analysis (SRA) and latent variable structural equation modeling (LVSEM); however, software to apply LVSEM to dichotomous variables like intention has only recently become available. No one has compared the methods to determine whether or not they yield similar results for dichotomous variables. ^ Study objectives were to: (1) determine whether the effect of subjective norms on mammography intention and stage of change are mediated by pros and cons; and (2) compare mediation results from the SRA and LVSEM approaches when the outcome is dichotomous. We conducted a secondary analysis of data from a national sample of women veterans enrolled in Project H.O.M.E. (H&barbelow;ealthy O&barbelow;utlook on the M&barbelow;ammography E&barbelow;xperience), a behavioral intervention trial. ^ Results showed that the TTM model described the causal pathways better than the TRA one; however, we found support for only one of the TTM causal mechanisms. Cons was the sole mediator. The mediated effect of subjective norms on intention and stage of change by cons was very small. These findings suggest that interventionists focus their efforts on reducing negative attitudes toward mammography when resources are limited. ^ Both the SRA and LVSEM methods provided evidence for complete mediation, and the direction, magnitude, and standard errors of the parameter estimates were very similar. Because SRA parameter estimates were not biased toward the null, we can probably assume negligible measurement error in the independent and mediator variables. Simulation studies are needed to further our understanding of how these two methods perform under different data conditions. ^

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It is widely acknowledged in theoretical and empirical literature that social relationships, comprising of structural measures (social networks) and functional measures (perceived social support) have an undeniable effect on health outcomes. However, the actual mechanism of this effect has yet to be clearly understood or explicated. In addition, comorbidity is found to adversely affect social relationships and health related quality of life (a valued outcome measure in cancer patients and survivors). ^ This cross sectional study uses selected baseline data (N=3088) from the Women's Healthy Eating and Living (WHEL) study. Lisrel 8.72 was used for the latent variable structural equation modeling. Due to the ordinal nature of the data, Weighted Least Squares (WLS) method of estimation using Asymptotic Distribution Free covariance matrices was chosen for this analysis. The primary exogenous predictor variables are Social Networks and Comorbidity; Perceived Social Support is the endogenous predictor variable. Three dimensions of HRQoL, physical, mental and satisfaction with current quality of life were the outcome variables. ^ This study hypothesizes and tests the mechanism and pathways between comorbidity, social relationships and HRQoL using latent variable structural equation modeling. After testing the measurement models of social networks and perceived social support, a structural model hypothesizing associations between the latent exogenous and endogenous variables was tested. The results of the study after listwise deletion (N=2131) mostly confirmed the hypothesized relationships (TLI, CFI >0.95, RMSEA = 0.05, p=0.15). Comorbidity was adversely associated with all three HRQoL outcomes. Strong ties were negatively associated with perceived social support; social network had a strong positive association with perceived social support, which served as a mediator between social networks and HRQoL. Mental health quality of life was the most adversely affected by the predictor variables. ^ This study is a preliminary look at the integration of structural and functional measures of social relationships, comorbidity and three HRQoL indicators using LVSEM. Developing stronger social networks and forming supportive relationships is beneficial for health outcomes such as HRQoL of cancer survivors. Thus, the medical community treating cancer survivors as well as the survivor's social networks need to be informed and cognizant of these possible relationships. ^

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There has been a great deal of interest and debate recently concerning the linkages between inequality and health cross-nationally. Exposures to social and health inequalities likely vary as a consequence of different cultural contexts. It is important to guide research by a theoretical perspective that includes cultural and social contexts cross-nationally. If inequality affects health only under specific cultural conditions, this could explain why some of the literature that compares different societies finds no evidence of a relationship between inequality and health in certain countries. A theoretical framework is presented that combines sociological theory with constructs from cultural psychology in order to identify pathways that might lead from cultural dimensions to health inequalities. Three analyses are carried out. The first analysis explores whether there is a relationship between cultural dimensions at the societal level and self-rated health at the individual level. The findings suggest that different cultural norms at the societal level can produce both social and health inequalities, but the effects on health may differ depending on the socio-cultural context. The second analysis tests the hypothesis that health is affected by the density of social networks in a society, levels of societal trust, and inequality. The results suggest that commonly used measures of social cohesion and inequality may have both contextual and compositional effects on health in a large number of countries, and that societal measures of social cohesion and inequality interact with individual measures of social participation, trust, and income, moderating their effects on health. The third analysis explores whether value systems associated with vertical individualist societies may lead to health disparities because of their stigmatizing effects. I test the hypothesis that, within vertical individualist societies, subjective well-being will be affected by a social context where competition and the Protestant work ethic are valued, mediated by inequality. The hypothesis was not supported by the available cross-national data, most likely because of inadequate measures, missing data, and the small sample of vertical individualist countries. The overall findings demonstrate that cultural differences are important contextual factors that should not be overlooked when examining the causes of health inequalities. ^

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This study addressed two purposes: (1) to determine the effect of person-environment fit on the psychological well-being of psychiatric aides and (2) to determine what role the coping resources of social support and control have on the above relationship. Two hundred and ten psychiatric aides working in a state hospital in Texas responded to a questionnaire pertaining to these issues.^ Person-environment fit, as a measure of occupational stress, was assessed through a modified version of the Work Environment Scale (WES). The WES subscales used in this study were: involvement, autonomy, job pressure, job clarity, and physical comfort. Psychological well-being was measured with the General Well-Being Schedule which was developed by the National Center for Health Statistics. Co-worker and supervisor support were measured through the WES and finally, control was assessed through Rotter's Locus of Control Scale.^ The results of this study were as follows: (1) all person-environment (p-e) dimensions appeared to have linear relationships with psychological well-being; (2) the p-e fit - well-being relationship did not appear to be confounded by demographic factors; (3) all p-e fit dimensions were significantly related to well-being except for autonomy; (4) p-e fit was more strongly related to well-being than the environmental measure alone; (5) supervisor support and non-work related support were found to have additive effects on the relationship between p-e fit and well-being, however no interaction or buffering effects were observed; (6) locus of control was found to have additive effects in the prediction of well-being and showed interactive effects with work pressure, involvement and physical comfort; and (7) the testing of the overall study model which included many of the components mentioned above yielded an R('2) = .27.^ Implications of these findings are discussed, future research suggested and applications proposed. ^

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El presente trabajo pretende rastrear cómo operan específicamente la lógica del parentesco y la lógica del Estado en determinadas situaciones y cómo se entrelazan o vinculan en otras, configurando de esta manera esquemas de organización que guían las prácticas económicas, las dinámicas políticas, las relaciones sociales, e inclusive, el mundo sagrado y las representaciones mentales en las sociedades precolombinas. La hipótesis fundamental es que el parentesco y el Estado se visualizan en la sociedad inka como los ejes de articulación social por excelencia, como lógicas que brindan los códigos y directrices de organización en el mundo inka

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Hace tiempo que, para el estudio de la transición del feudalismo al capitalismo, se consideran esenciales los procesos de transformación que afectaron al campesinado europeo de la Baja Edad Media. Este trabajo analiza la forma en la que se relacionan el proceso de diferenciación social y el desarrollo de los mercados locales en Castilla, en los siglos XIV y XV. En primer lugar se examinan distintas tesis historiográficas, que tienen en común el haber enfocado el problema desde una perspectiva lógico-abstracta, dejando de lado la forma específica en que funcionan los mercados campesinos. Luego se propone, por contraste, en base al análisis de la documentación de la ciudad de Ávila, una hipótesis alternativa, mostrando la existencia de formas de intercambio desigual que posibilitan la acumulación capitalista a nivel aldeano, y crean las condiciones para el surgimiento de una estructura de clases moderna.

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En los últimos años se han producido importantes transformaciones en la activiad agrícola argentina. Una de ellas es la aparición de nuevos formas de organización de la agricultura que se denominan genéricamente 'pools de siembra', los cuales impactan en los territorios locales modificando tanto los roles y las funciones de los actores agrarios tradicionales como las relaciones que mantienen entre ellos. Bajo la hipótesis de que estas nuevas formas de organización de la agricultura, llevadas a cabo por actores de tipo más financiero que socioproductivo, aceleran los procesos de concentración y desterritorialización de la riqueza, se avanza en este trabajo sobre cuatro aspectos. En primer lugar, se caracteriza a los actores actuales vinculados a la producción primaria, considerando su trayectoria y su relación con la actividad agrícola y con el espacio local. En segundo lugar, nos concentramos en esas nuevas formas de organización de la agricultura, tratando de mostrar que detrás de la denominación de 'pools de siembra' se esconde una diversidad de actores; para ello, el presente estudio articula tres variables principales: la duración del emprendimiento agrícola, la forma jurídica adoptada y el actor responsable de la gestión. En tercer lugar, se profundiza en las lógicas decisorias de los propietarios rentistas, actores clave junto con los contratistas en el avance de los pools de siembra. Por último, se describe algunos de los impactos actualmente perceptibles de estas nuevas formas de organización en los espacios centrales santafesinos

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La política social y el mercado de trabajo son dimensiones del sistema social mutuamente implicadas en las sociedades industriales capitalistas. Sin embargo, una interpretación apresurada sobre el mundo social podría opacar los procesos que hacen que en un grupo de la población se yuxtapongan: una inserción laboral precaria dentro del mercado de trabajo informal junto con la (re) construcción de ese grupo como sujeto-objeto de políticas sociales. El artículo tiene por propósito problematizar las representaciones dominantes sobre el trabajo y su relación con las prácticas de organización de los hogares, considerando que en su interior la dimensión laboral se articula con otros recursos (provenientes de las políticas sociales). De modo más específico, el objetivo se orienta a la descripción y análisis de prácticas y representaciones sobre la situaci162n ocupacional de jefas/es y cónyuges que realizan actividades laborales en la informalidad de subsistencia. Se plantea como hipótesis exploratoria que en el período actual las condiciones de trabajo y representaciones de los trabajadores ocupados en ese tipo de actividades expresarían la existencia de un tipo de informalidad fuertemente segregada respecto de las actividades productivas, un en un contexto de crecimiento del empleo. También se sostiene que las formas bajo las cuales estas inserciones laborales se articulan con los planes sociales (como un nivel específico de política social) evidenciarían el carácter de la contribución estatal a la reproducción de las condiciones de vida de los trabajadores insertos en este tipo de informalidad. Los hallazgos presentados constituyen un avance de investigación sobre la reproducción de la marginalidad urbana en el Conurbano Bonaerense. Parte del trabajo de campo se realizó durante el año 2008, en un barrio del Partido de Almirante Brown. Se organizaron dos grupos de discusión: uno con mujeres perceptoras de planes y otro con hombres que realizaban changas como actividad principal. Con el objeto de aportar datos acerca de las condiciones materiales de los hogares, se aplicó un cuestionario a los participantes. Junto con esta información, se analizaron registros de campo tomados en observaciones realizadas en diversos espacios del barrio

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El presente trabajo pretende rastrear cómo operan específicamente la lógica del parentesco y la lógica del Estado en determinadas situaciones y cómo se entrelazan o vinculan en otras, configurando de esta manera esquemas de organización que guían las prácticas económicas, las dinámicas políticas, las relaciones sociales, e inclusive, el mundo sagrado y las representaciones mentales en las sociedades precolombinas. La hipótesis fundamental es que el parentesco y el Estado se visualizan en la sociedad inka como los ejes de articulación social por excelencia, como lógicas que brindan los códigos y directrices de organización en el mundo inka

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Hace tiempo que, para el estudio de la transición del feudalismo al capitalismo, se consideran esenciales los procesos de transformación que afectaron al campesinado europeo de la Baja Edad Media. Este trabajo analiza la forma en la que se relacionan el proceso de diferenciación social y el desarrollo de los mercados locales en Castilla, en los siglos XIV y XV. En primer lugar se examinan distintas tesis historiográficas, que tienen en común el haber enfocado el problema desde una perspectiva lógico-abstracta, dejando de lado la forma específica en que funcionan los mercados campesinos. Luego se propone, por contraste, en base al análisis de la documentación de la ciudad de Ávila, una hipótesis alternativa, mostrando la existencia de formas de intercambio desigual que posibilitan la acumulación capitalista a nivel aldeano, y crean las condiciones para el surgimiento de una estructura de clases moderna.

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En los últimos años se han producido importantes transformaciones en la activiad agrícola argentina. Una de ellas es la aparición de nuevos formas de organización de la agricultura que se denominan genéricamente 'pools de siembra', los cuales impactan en los territorios locales modificando tanto los roles y las funciones de los actores agrarios tradicionales como las relaciones que mantienen entre ellos. Bajo la hipótesis de que estas nuevas formas de organización de la agricultura, llevadas a cabo por actores de tipo más financiero que socioproductivo, aceleran los procesos de concentración y desterritorialización de la riqueza, se avanza en este trabajo sobre cuatro aspectos. En primer lugar, se caracteriza a los actores actuales vinculados a la producción primaria, considerando su trayectoria y su relación con la actividad agrícola y con el espacio local. En segundo lugar, nos concentramos en esas nuevas formas de organización de la agricultura, tratando de mostrar que detrás de la denominación de 'pools de siembra' se esconde una diversidad de actores; para ello, el presente estudio articula tres variables principales: la duración del emprendimiento agrícola, la forma jurídica adoptada y el actor responsable de la gestión. En tercer lugar, se profundiza en las lógicas decisorias de los propietarios rentistas, actores clave junto con los contratistas en el avance de los pools de siembra. Por último, se describe algunos de los impactos actualmente perceptibles de estas nuevas formas de organización en los espacios centrales santafesinos