333 resultados para Freedman


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Esophageal (EA) and esophagogastric junction (EGJA) adenocarcinoma have been steadily increasing in frequency in younger people, however the etiology of these cancers is poorly understood. We therefore investigated associations of body- mass index (BMI), cigarette smoking, alcohol consumption, gastroesophageal reflux, and use of non-steroidal anti-inflammatory drugs (NSAIDs) in relation to age-specific risks of EA and EGJA. We pooled individual participant data from eight population-based, case-control studies within the international Barrett’s and Esophageal Adenocarcinoma Consortium (BEACON). The analysis included 1,363 EA patients, 1,472 EGJA patients, and 5,728 control participants. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for age-specific (<50, 50–59, 60–69, ≥70 years) cancer outcomes, as well as interactions by age. BMI, smoking status and pack-years, recurrent gastroesophageal reflux, and frequency of gastroesophageal reflux were positively associated with EA and EGJA in each age group. Early-onset EA (<50 years) had stronger associations with recurrent gastroesophageal reflux (OR=8.06, 95%CI: 4.52, 14.37; Peffect modification=0.01) and BMI (ORBMI ≥30 vs. <25=4.19, 95%CI: 2.23, 7.87; Peffect modification=0.04), relative to older age groups. In contrast, inverse associations of NSAID use were strongest in the oldest age group (≥70 years), although this apparent difference was not statistically significant. Age-specific associations with EGJA showed similar, but slightly weaker patterns and no statistically significant differences by age were observed. Our study provides evidence that associations between obesity and gastroesophageal reflux are stronger among earlier onset EA cancers.

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OBJECTIVE: To investigate the impact of smoking and smoking cessation on cardiovascular mortality, acute coronary events, and stroke events in people aged 60 and older, and to calculate and report risk advancement periods for cardiovascular mortality in addition to traditional epidemiological relative risk measures.

DESIGN: Individual participant meta-analysis using data from 25 cohorts participating in the CHANCES consortium. Data were harmonised, analysed separately employing Cox proportional hazard regression models, and combined by meta-analysis.

RESULTS: Overall, 503,905 participants aged 60 and older were included in this study, of whom 37,952 died from cardiovascular disease. Random effects meta-analysis of the association of smoking status with cardiovascular mortality yielded a summary hazard ratio of 2.07 (95% CI 1.82 to 2.36) for current smokers and 1.37 (1.25 to 1.49) for former smokers compared with never smokers. Corresponding summary estimates for risk advancement periods were 5.50 years (4.25 to 6.75) for current smokers and 2.16 years (1.38 to 2.39) for former smokers. The excess risk in smokers increased with cigarette consumption in a dose-response manner, and decreased continuously with time since smoking cessation in former smokers. Relative risk estimates for acute coronary events and for stroke events were somewhat lower than for cardiovascular mortality, but patterns were similar.

CONCLUSIONS: Our study corroborates and expands evidence from previous studies in showing that smoking is a strong independent risk factor of cardiovascular events and mortality even at older age, advancing cardiovascular mortality by more than five years, and demonstrating that smoking cessation in these age groups is still beneficial in reducing the excess risk.

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INTRODUCTION: Smoking is known to be a major cause of death among middle-aged adults, but evidence on its impact and the benefits of smoking cessation among older adults has remained limited. Therefore, we aimed to estimate the influence of smoking and smoking cessation on all-cause mortality in people aged ≥60 years.

METHODS: Relative mortality and mortality rate advancement periods (RAPs) were estimated by Cox proportional hazards models for the population-based prospective cohort studies from Europe and the U.S. (CHANCES [Consortium on Health and Ageing: Network of Cohorts in Europe and the U.S.]), and subsequently pooled by individual participant meta-analysis. Statistical analyses were performed from June 2013 to March 2014.

RESULTS: A total of 489,056 participants aged ≥60 years at baseline from 22 population-based cohort studies were included. Overall, 99,298 deaths were recorded. Current smokers had 2-fold and former smokers had 1.3-fold increased mortality compared with never smokers. These increases in mortality translated to RAPs of 6.4 (95% CI=4.8, 7.9) and 2.4 (95% CI=1.5, 3.4) years, respectively. A clear positive dose-response relationship was observed between number of currently smoked cigarettes and mortality. For former smokers, excess mortality and RAPs decreased with time since cessation, with RAPs of 3.9 (95% CI=3.0, 4.7), 2.7 (95% CI=1.8, 3.6), and 0.7 (95% CI=0.2, 1.1) for those who had quit <10, 10 to 19, and ≥20 years ago, respectively.

CONCLUSIONS: Smoking remains as a strong risk factor for premature mortality in older individuals and cessation remains beneficial even at advanced ages. Efforts to support smoking abstinence at all ages should be a public health priority.

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BACKGROUND: Smoking is the most important individual risk factor for many cancer sites but its association with breast and prostate cancer is not entirely clear. Rate advancement periods (RAPs) may enhance communication of smoking related risk to the general population. Thus, we estimated RAPs for the association of smoking exposure (smoking status, time since smoking cessation, smoking intensity, and duration) with total and site-specific (lung, breast, colorectal, prostate, gastric, head and neck, and pancreatic) cancer incidence and mortality.

METHODS: This is a meta-analysis of 19 population-based prospective cohort studies with individual participant data for 897,021 European and American adults. For each cohort we calculated hazard ratios (HRs) for the association of smoking exposure with cancer outcomes using Cox regression adjusted for a common set of the most important potential confounding variables. RAPs (in years) were calculated as the ratio of the logarithms of the HRs for a given smoking exposure variable and age. Meta-analyses were employed to summarize cohort-specific HRs and RAPs.

RESULTS: Overall, 140,205 subjects had a first incident cancer, and 53,164 died from cancer, during an average follow-up of 12 years. Current smoking advanced the overall risk of developing and dying from cancer by eight and ten years, respectively, compared with never smokers. The greatest advancements in cancer risk and mortality were seen for lung cancer and the least for breast cancer. Smoking cessation was statistically significantly associated with delays in the risk of cancer development and mortality compared with continued smoking.

CONCLUSIONS: This investigation shows that smoking, even among older adults, considerably advances, and cessation delays, the risk of developing and dying from cancer. These findings may be helpful in more effectively communicating the harmful effects of smoking and the beneficial effect of smoking cessation.

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A witness seminar on Britain's decision to withdraw from East of Suez was held by the Institute of Contemporary British History at King's College London on 16 November 1990. It was introduced by a short paper by David Greenwood of the Centre for the Study of Defence Economics, University of Aberdeen. Those participating were Professor Lawrence Freedman (Chairman), David Greenwood, Sir Frank Cooper, C.W. Wright, Sir Patrick Nairne, Richard Hastie‐Smith, J.K. Wright, Sir Ewen Broadbent, Peter Hudson, Sir Robert Andrew, Sir George Leitch, Sir Arthur Drew, Lord Thomson of Monifieth, Lord Zuckerman, Lord Mayhew and Field Marshal Lord Carver. The Institute of Contemporary British History would like to record its thanks to BP for its sponsorship of this event.

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Numerous definitions of forgiveness have been proposed in the literature (e.g.. North, 1987; Enright, Freedman & Rique, 1998), most ofwhich are based on religious or philosophical notions, rather than on empirical evidence. Definitions employed by researchers have typically set very high standards for forgiveness. This research was designed to investigate the possibility that these definitions describe an ideal of forgiveness and may not reflect laypersons' beliefe and experiences. Using Higgins' Self-Discrepancy Theory as a fiamework, three types of forgiveness beliefs were investigated: actual, ideal, and ought Q-methodology (which permits intensive study ofphenomena in small samples) was employed to examine and compare participants' beliefs about forgiveness across these domains. Thirty participants (20 women), 25 to 78 years of age, were recruited firom the community. They were asked to sort a set of66 statements about forgiveness according to their level of agreement with each statement This process was repeated three times, with the goal of modelling participants' actual experiences, their ideals, and how they believed forgiveness ought to be. Three perspectives on forgiveness emerged across the domains: forgiveness as motivated by religious beliefs, reconciliation-focussed forgiveness, and conflicted forgiveness. These perspectives indicated that, for many participants, the definitions presented in the literature may coincide with their beliefs about how forgiveness would ideally be and should be, as well as with their experiences of forgiveness; however, a large number of participants' experiences of, and beliefs about, forgiveness do not conform to the standards set out in the literature, and to exclude these participants' experiences and beliefs would mean overlooking what forgiveness means to a large portion of people. Results of this study indicate that researchers need to keep an open mind about what forgiveness may mean to their participants.

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Ce travail de recherche cherche à répondre à deux questions : Quels sont les liens sociaux liant les maîtres et ingénus aux dépendants, sont-ils plus importants entre ingénus et affranchis qu’entre ingénus et esclaves? Ont-ils une influence positive sur l’affranchissement des esclaves dans la Correspondance de Cicéron ? Cette étude évolue par thème, passant des liens amicaux, matrimoniaux, sexuels aux évaluations des maîtres et des patrons sur leurs esclaves et affranchis. Avant la conclusion, quelques pages seront également dévolues aux esclaves et affranchis absents de la Correspondance pour expliquer cette absence et les situer dans le contexte de la fin de la République romaine. L’étude des liens sociaux liant les dépendants aux maîtres, patrons et ingénus, dans une approche soulignant les liens amicaux, affectifs, maritaux et sexuels plutôt que les liens sociaux purement juridiques, a permis de prouver l’existence assez fréquente de liens amicaux et affectifs entre les dépendants (esclaves et affranchis) et les maîtres, les patrons et les ingénus dans la Correspondance. L’étude de la Correspondance démontre également que ses liens amicaux et affectifs étaient plus nombreux et plus soutenus entre affranchis et ingénus qu’entre ingénus et esclave, mettant en lumière l’importance des liens d’amitié et d’affection dans le processus d’affranchissement de certains esclaves.

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In a recent experiment, Freedman et al. recorded from inferotemporal (IT) and prefrontal cortices (PFC) of monkeys performing a "cat/dog" categorization task (Freedman 2001 and Freedman, Riesenhuber, Poggio, Miller 2001). In this paper we analyze the tuning properties of view-tuned units in our HMAX model of object recognition in cortex (Riesenhuber 1999) using the same paradigm and stimuli as in the experiment. We then compare the simulation results to the monkey inferotemporal neuron population data. We find that view-tuned model IT units that were trained without any explicit category information can show category-related tuning as observed in the experiment. This suggests that the tuning properties of experimental IT neurons might primarily be shaped by bottom-up stimulus-space statistics, with little influence of top-down task-specific information. The population of experimental PFC neurons, on the other hand, shows tuning properties that cannot be explained just by stimulus tuning. These analyses are compatible with a model of object recognition in cortex (Riesenhuber 2000) in which a population of shape-tuned neurons provides a general basis for neurons tuned to different recognition tasks.

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La Fibrosis Quística es la enfermedad autosómica recesiva mas frecuente en caucásicos. En Colombia no se conoce la incidencia de la enfermedad, pero investigaciones del grupo de la Universidad del Rosario indican que podría ser relativamente alta. Objetivo: Determinar la incidencia de afectados por Fibrosis Quística en una muestra de recién nacidos de la ciudad de Bogotá. Metodología: Se analizan 8.297 muestras de sangre de cordón umbilical y se comparan tres protocolos de tamizaje neonatal: TIR/TIR, TIR/DNA y TIR/DNA/TIR. Resultados: El presente trabajo muestra una incidencia de 1 en 8.297 afectados en la muestra analizada. Conclusiones: Dada la relativamente alta incidencia demostrada en Bogotá, se justifica la implementación de Tamizaje Neonatal para Fibrosis Quística en Colombia.

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En la literatura económica no se ha estudiado como la competencia entre las instituciones educativas afecta específicamente la escogencia de estándares educativos y el valor de matrícula. Usando un modelo teórico analizo como la competencia entre las instituciones educativas afectan la escogencia de estándares académicos, comparando la solución en competencia con la solución eficiente y la solución de monopolio. Los individuos son heterogéneos y se diferencian en su habilidad, las instituciones educativas compiten estableciendo en una primera etapa el estándar educativo, y en una segunda etapa el valor de matrícula. Una vez definidos los estándares y los valores de matrícula, estos son información pública, permitiendo a los individuos escoger entre ingresar o no a una institución educativa o a que institución educativa ingresar de acuerdo a la habilidad innata y al costo asociado al esfuerzo. En los resultados se muestra que el bienestar social aumenta cuando en la economía existe más de una institución educativa con estándares diferentes, y la solución de mercado, en monopolio o en competencia, obliga a los estudiantes a ejercer un mayor esfuerzo para alcanzar el título. Independiente a la relación de costos, el valor de matrícula es siempre mayor para la institución con estándar educativo más alto, y mayor en la solución de mercado. Cuando el costo unitario de la institución con estándar más alto es mayor o igual al costo de la institución con menor estándar, los estándares educativos escogidos por el planificador son mayores y el esfuerzo requerido por los individuos es menor respecto a la solución de mercado.

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Introducción: El glaucoma representa la tercera causa de ceguera a nivel mundial y un diagnóstico oportuno requiere evaluar la excavación del nervio óptico que está relacionada con el área del mismo. Existen reportes de áreas grandes (macrodiscos) que pueden ser protectoras, mientras otros las asocian a susceptibilidad para glaucoma. Objetivo: Establecer si existe asociación entre macrodisco y glaucoma en individuos estudiados con Tomografía Optica Coherente (OCT ) en la Fundación Oftalmológica Nacional. Métodos: Estudio transversal de asociación que incluyó 25 ojos con glaucoma primario de ángulo abierto y 74 ojos sanos. A cada individuo se realizó examen oftalmológico, campo visual computarizado y OCT de nervio óptico. Se compararon por grupos áreas de disco óptico y número de macrodiscos, definidos según Jonas como un área de la media más dos desviaciones estándar y según Adabache como área ≥3.03 mm2 quien evaluó población Mexicana. Resultados: El área promedio de disco óptico fue 2,78 y 2,80 mm2 glaucoma Vs. sanos. De acuerdo al criterio de Jonas, se observó un macrodisco en el grupo sanos y según criterio de Adabache se encontraron ocho y veinticinco macrodiscos glaucoma Vs. sanos. (OR=0,92 IC95%=0.35 – 2.43). Discusión: No hubo diferencia significativa (P=0.870) en el área de disco entre los dos grupos y el porcentaje de macrodiscos para los dos grupos fue similar, aunque el bajo número de éstos no permitió concluir en términos estadísticos sobre la presencia de macrodisco y glaucoma.