199 research outputs found

    Larval settlement in echinoderms: a review of processes and patterns

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    Echinoderms are a common component of benthic marine ecosystems, with many being ecologically and/or economically important. Like many marine organisms, most echinoderms have a bipartite life history with a planktonic larval phase and a benthic adult phase. The transition between these phases (i.e. settlement) is complex and comprises a cascade of events including the location, exploration and selection of suitable benthic habitat, and metamorphosis to adapt from a pelagic to a benthic lifestyle. This review provides a comprehensive synthesis of the various processes involved in the settlement phase across all five extant classes of echinoderms. Central to the review is a detailed assessment of settlement behaviour and the diverse mechanisms of settlement induction. Most echinoderms, including keystone sea urchins, starfishes and sea cucumbers, do not settle indiscriminately; specific environmental conditions or cues are often necessary for settlement to occur, resulting in marked spatial and temporal variability in settlement rates. Fluctuations in settlement, in turn, lead to major changes in the local abundance of echinoderms and often have profound ecological consequences, due to the pivotal role that many echinoderms play in ecosystem functioning. Given important knowledge gaps persist, this review also explores opportunities for future research to advance our understanding of this critical early life-history phase

    Uterine Weight as a Modifier of Black/White Racial Disparities in Minimally Invasive Hysterectomy Among Veterans with Fibroids in the Veterans Health Administration

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    INTRODUCTION: Uterine fibroids are the most common indication for hysterectomy. Minimally invasive hysterectomy (MIH) confers lower risk of complications and shorter recovery than open surgical procedures; however, it is more challenging to perform with larger fibroids. There are racialized differences in fibroid size and MIH rates. We examined the role of uterine size in black-white differences in MIH among Veterans in the Department of Veterans Affairs (VA). METHODS: Using VA clinical and administrative data, we conducted a cross-sectional study among black and white Veterans with fibroids who underwent hysterectomy between 2012 and 2014. We abstracted postoperative uterine weight from pathology reports as a proxy for uterine size. We used a generalized linear model to estimate the association between race and MIH and tested an interaction between race and postoperative uterine weight (≀250 g vs. \u3e250 g). We estimated adjusted marginal effects for racial differences in MIH by postoperative uterine weight. RESULTS: The sample included 732 Veterans (60% black, 40% white). Postoperative uterine weight modified the association of race and MIH (p for interaction=0.05). Black Veterans with postoperative uterine weight ≀250 g had a nearly 12-percentage point decrease in MIH compared to white Veterans (95% CI -23.1 to -0.5), with no difference by race among those with postoperative uterine weight \u3e250 g. DISCUSSION: The racial disparity among Veterans with small fibroids who should be candidates for MIH underscores the role of other determinants beyond uterine size. To eliminate disparities in MIH, research focused on experiences of black Veterans, including pathways to treatment and provider-patient interactions, is needed

    A discrete latent factor model of smoking, cancer and mortality

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    This paper investigates the relationship between smoking and ill-health, with a focus on the onset of cancer. A discrete latent factor model for smoking and health outcomes, allowing for these to be commonly affected by unobserved factors, is jointly estimated, using the British Health and Lifestyle Survey (HALS) dataset. Post-estimation predictions suggest the reduction in time-to-cancer to be 5.7 years for those with an exposure of 30 pack-years, compared to never-smokers. Estimation of posterior probabilities for class membership shows that individuals in certain classes exhibit similar observables but highly divergent health outcomes, suggesting that unobserved factors influence outcomes. The use of a joint model changes the results substantially. The results show that failure to account for unobserved heterogeneity leads to differences in survival times between those with different smoking exposures to be overestimated by more than 50% (males, with 30 pack-years of exposure)

    Obesity, unhappiness, and the challenge of affluence : theory and evidence

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    Is affluence a good thing? The book "The Challenge of Affluence" by Avner Offer (2006) argues that economic prosperity weakens self-control and undermines human well-being. Consistent with a pessimistic view, we show that psychological distress has been rising through time in modern Great Britain. Taking over-eating as an example, our data reveal that half the British population view themselves as overweight, and that happiness and mental health are worse among fatter people in Britain and Germany. Comparisons also matter. We discuss problems of inference and argue that longitudinal data are needed. We suggest a theory of obesity imitation where utility depends on relative weight

    Informing investment to reduce inequalities: a modelling approach

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    Background: Reducing health inequalities is an important policy objective but there is limited quantitative information about the impact of specific interventions. Objectives: To provide estimates of the impact of a range of interventions on health and health inequalities. Materials and methods: Literature reviews were conducted to identify the best evidence linking interventions to mortality and hospital admissions. We examined interventions across the determinants of health: a ‘living wage’; changes to benefits, taxation and employment; active travel; tobacco taxation; smoking cessation, alcohol brief interventions, and weight management services. A model was developed to estimate mortality and years of life lost (YLL) in intervention and comparison populations over a 20-year time period following interventions delivered only in the first year. We estimated changes in inequalities using the relative index of inequality (RII). Results: Introduction of a ‘living wage’ generated the largest beneficial health impact, with modest reductions in health inequalities. Benefits increases had modest positive impacts on health and health inequalities. Income tax increases had negative impacts on population health but reduced inequalities, while council tax increases worsened both health and health inequalities. Active travel increases had minimally positive effects on population health but widened health inequalities. Increases in employment reduced inequalities only when targeted to the most deprived groups. Tobacco taxation had modestly positive impacts on health but little impact on health inequalities. Alcohol brief interventions had modestly positive impacts on health and health inequalities only when strongly socially targeted, while smoking cessation and weight-reduction programmes had minimal impacts on health and health inequalities even when socially targeted. Conclusions: Interventions have markedly different effects on mortality, hospitalisations and inequalities. The most effective (and likely cost-effective) interventions for reducing inequalities were regulatory and tax options. Interventions focused on individual agency were much less likely to impact on inequalities, even when targeted at the most deprived communities

    Association between statin use after diagnosis of esophageal cancer and survival: a population-based cohort study

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    Background & Aims: Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors), commonly prescribed to prevent cardiovascular disease, promote apoptosis and limit proliferation of esophageal cancer cell lines. We investigated whether statin use following diagnosis of esophageal cancer is associated with reduced esophageal cancer-specific and all-cause mortality.  Methods: We identified a cohort of 4445 men and women in the United Kingdom diagnosed with esophageal cancer from January 2000 through November 2009 using the General Practice Research Database. The National Cancer Registry and Office of National Statistics datasets respectively established the histologic subtype and cancer-specific mortality. Cox proportional hazard regression analysis with time-dependent exposures estimated the association between statin use after diagnosis and esophageal cancer-specific and all-cause mortality.  Results: The median survival time of the entire cohort was 9.2 months (inter-quartile range [IQR], 3.7–23.2 months). Among subjects who used statins after diagnosis of esophageal cancer, the median survival time was 14.9 months (IQR, 7.1–52.3) compared to 8.1 months for non-users (IQR, 3.3–20). In the entire cohort, statin use after diagnosis was associated with a decreased risk of esophageal cancer-specific mortality (adjusted hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.44–0.86) and all-cause mortality (HR, 0.67; 95% CI, 0.58–0.77). In patients with esophageal adenocarcinoma, statin use after diagnosis was associated with decreased risk of esophageal cancer-specific mortality (HR, 0.61; 95% CI 0.38–0.96) and all-cause mortality (HR, 0.63; 95% 0.43–0.92). This effect was not observed in patients with esophageal squamous cell carcinoma. There was no evidence for effect modification of these associations with statin use before cancer diagnosis.  Conclusions: In a large population-based cohort, statin use after diagnosis of esophageal adenocarcinoma, but not esophageal squamous cell carcinoma, was associated with reduced esophageal cancer-specific and all-cause mortality
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