353 research outputs found
Multiple metrics of latitudinal patterns in insect pollination and herbivory for a tropicalâtemperate congener pair
The biotic interactions hypothesis posits that biotic interactions are more important drivers of adaptation closer to the equator, evidenced by âstrongerâ contemporary interactions (e.g. greater interaction rates) and/or patterns of trait evolution consistent with a history of stronger interactions. Support for the hypothesis is mixed, but few studies span tropical and temperate regions while experimentally controlling for evolutionary history. Here, we integrate field observations and common garden experiments to quantify the relative importance of pollination and herbivory in a pair of tropicalâtemperate congeneric perennial herbs. Phytolacca rivinoides and P. americana are pioneer species native to the Neotropics and the eastern USA, respectively. We compared plantâpollinator and plantâherbivore interactions between three tropical populations of P. rivinoides from Costa Rica and three temperate populations of P. americana from its northern range edge in Michigan and Ohio. For some metrics of interaction importance, we also included three subtropical populations of P. americana from its southern range edge in Florida. This approach confounds species and region but allows us, uniquely, to measure complementary proxies of interaction importance across a tropicalâtemperate range in one system. To test the prediction that lowerâlatitude plants are more reliant on insect pollinators, we quantified floral display and reward, insect visitation rates, and selfâpollination ability (autogamy). To test the prediction that lowerâlatitude plants experience more herbivore pressure, we quantified herbivory rates, herbivore abundance, and leaf palatability. We found evidence supporting the biotic interactions hypothesis for most comparisons between P. rivinoides and northâtemperate P. americana (floral display, insect visitation, autogamy, herbivory, herbivore abundance, and youngâleaf palatability). Results for subtropical P. americana populations, however, were typically not intermediate between P. rivinoides and northâtemperate P. americana, as would be predicted by a linear latitudinal gradient in interaction importance. Subtropical youngâleaf palatability was intermediate, but subtropical mature leaves were the least palatable, and pollinationârelated traits did not differ between temperate and subtropical regions. These nonlinear patterns of interaction importance suggest future work to relate interaction importance to climatic or biotic thresholds. In sum, we found that the biotic interactions hypothesis was more consistently supported at the larger spatial scale of our study
Toenail selenium concentrations and bladder cancer risk in women and men
Prediagnostic selenium concentrations measured in archived toenails were inversely associated with bladder cancer risk in women (P for trend=0.02), but not in men, in a nested caseâcontrol study of 338 cases and 341 matched controls. These findings may be due to chance and more studies are needed to determine whether associations between selenium and bladder cancer risk differ by sex
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Comprehensive default methodology for the analysis of exposures to mixtures of chemicals accidentally released to the atmosphere
Safety analysis of Department of Energy (DOE) facilities requires consideration of potential exposures to mixtures of chemicals released to the atmosphere. Exposure to chemical mixtures may lead to additive, synergistic, or antagonistic health effects. In the past, the consequences of each chemical have been analyzed separately. This approach may not adequately protect the health of persons exposed to mixtures. However, considerable time would be required to evaluate all possible mixtures. The objective of this paper is to present reasonable default methodology developed by the EFCOG Safety Analysis Working Group Nonradiological Hazardous Material Subgroup (NHMS) for use in safety analysis within the DOE Complex
Human immunodeficiency virus and AIDS and other important predictors of maternal mortality in Mulago Hospital Complex Kampala Uganda
BACKGROUND: Women with severe maternal morbidity are at high risk of dying. Quality and prompt management and sometimes luck have been suggested to reduce on the risk of dying. The objective of the study was to identify the direct and indirect causes of severe maternal morbidity, predictors of progression from severe maternal morbidity to maternal mortality in Mulago hospital, Kampala, Uganda. METHODS: This was a longitudinal follow up study at the Mulago hospital's Department of Obstetrics and Gynaecology. Participants were 499 with severe maternal morbidity admitted in Mulago hospital between 15th November 2001 and 30th November 2002 were identified, recruited and followed up until discharge or death. Potential prognostic factors were HIV status and CD4 cell counts, socio demographic characteristics, medical and gynaecological history, past and present obstetric history and intra- partum and postnatal care. RESULTS: Severe pre eclampsia/eclampsia, obstructed labour and ruptured uterus, severe post partum haemorrhage, severe abruptio and placenta praevia, puerperal sepsis, post abortal sepsis and severe anaemia were the causes for the hospitalization of 499 mothers. The mortality incidence rate was 8% (n = 39), maternal mortality ratio of 7815/100,000 live births and the ratio of severe maternal morbidity to mortality was 12.8:1.The independent predictors of maternal mortality were HIV/AIDS (OR 5.1 95% CI 2-12.8), non attendance of antenatal care (OR 4.0, 95% CI 1.3-9.2), non use of oxytocics (OR 4.0, 95% CI 1.7-9.7), lack of essential drugs (OR 3.6, 95% CI 1.1-11.3) and non availability of blood for transfusion (OR 53.7, 95% CI (15.7-183.9) and delivery of amale baby (OR 4.0, 95% CI 1.6-10.1). CONCLUSION: The predictors of progression from severe maternal morbidity to mortality were: residing far from hospital, low socio economic status, non attendance of antenatal care, poor intrapartum care, and HIV/AIDS.There is need to improve on the referral system, economic empowerment of women and to offer comprehensive emergency obstetric care so as to reduce the maternal morbidity and mortality in our community
A caseâcontrol study of selenium in nails and prostate cancer risk in British men
In view of the experimental evidence suggesting that the micronutrient selenium reduces prostate cancer risk, we investigated the association between the selenium level in fingernails, a measure of long-term selenium intake, and prostate cancer risk in a case-control study among 656 British men, conducted in 1989-1992. Nail clippings were taken at the time of recruitment and selenium concentration, measured using neutron activation techniques, was successfully assayed for 300 case-control pairs and varied six-fold among the controls (0.59 p.p.m.; interquartile range, 0.50-0.71 p.p.m.). Nail selenium concentration was not significantly associated with prostate cancer risk: men in the highest quartile of nail selenium had a slightly increased risk compared with men in the lowest quartile (OR 1.24, 95 CI, 0.73-2.10); for advanced prostate cancer, men in the highest quartile had a slightly reduced risk compared with men in the lowest quartile (OR 0.78, 95% CI, 0.27-2.25). These results suggest that selenium is not strongly associated with prostate cancer risk in British men
Cost-efficiency assessment of Advanced Life Support (ALS) courses based on the comparison of advanced simulators with conventional manikins
<p>Abstract</p> <p>Background</p> <p>Simulation is an essential tool in modern medical education. The object of this study was to assess, in cost-effective measures, the introduction of new generation simulators in an adult life support (ALS) education program.</p> <p>Methods</p> <p>Two hundred fifty primary care physicians and nurses were admitted to ten ALS courses (25 students per course). Students were distributed at random in two groups (125 each). Group A candidates were trained and tested with standard ALS manikins and Group B ones with new generation emergency and life support integrated simulator systems.</p> <p>Results</p> <p>In group A, 98 (78%) candidates passed the course, compared with 110 (88%) in group B (p < 0.01). The total cost of conventional courses was âŹ7689 per course and the cost of the advanced simulator courses was âŹ29034 per course (p < 0.001). Cost per passed student was âŹ392 in group A and âŹ1320 in group B (p < 0.001).</p> <p>Conclusion</p> <p>Although ALS advanced simulator systems may slightly increase the rate of students who pass the course, the cost-effectiveness of ALS courses with standard manikins is clearly superior.</p
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