Water oxidation is a key chemical transformation for the conversion of solar energy into chemical fuels. Our review focuses on recent work on robust earth-abundant heterogeneous catalysts for the ...oxygen-evolving reaction (OER). We point out that improvements in the performance of OER catalysts will depend critically on the success of work aimed at understanding reaction barriers based on atomic-level mechanisms. We highlight the challenge of obtaining acid-stable OER catalysts, with proposals for elements that could be employed to reach this goal. We suggest that future advances in solar fuels science will be accelerated by the development of new methods for materials synthesis and characterization, along with in-depth investigations of redox mechanisms at catalytic surfaces.
Tropical forests account for approximately half of above-ground carbon stored in global vegetation. However, uncertainties in tropical forest carbon stocks remain high because it is costly and ...laborious to quantify standing carbon stocks. Carbon stocks of tropical forests are determined using allometric relations between tree stem diameter and height and biomass. Previous work has shown that the inclusion of height in biomass allometries, compared to the sole use of diameter, significantly improves biomass estimation accuracy. Here, we evaluate the effect of height measurement error on biomass estimation and we evaluate the accuracy of recently published diameter-height allometries at four areas within the Brazilian Amazon. As no destructive sample of biomass was available at these sites, reference biomass values were based on allometries. We found that the precision of individual tree height measurements ranged from 3 to 20% of total height. This imprecision resulted in a 5-6% uncertainty in biomass when scaled to 1 ha transects. Individual height measurement may be replaced with existing regional and global height allometries. However, we recommend caution when applying these relations. At Tapajos National Forest in the Brazilian state of Pará, using the pantropical and regional allometric relations for height resulted in site biomass 21% and 25% less than reference values. At the other three study sites, the pantropical equation resulted in errors of less that 2%, and the regional allometry produced errors of less than 12%. As an alternative to measuring all tree heights or to using regional and pantropical relations, we recommend measuring height for a well-distributed sample of about 100 trees per site. Following this methodology, 95% confidence intervals of transect biomass were constrained to within 4.5% on average when compared to reference values.
Cash transfers and vouchers are forms of 'demand-side financing' that have been widely used to promote maternal and newborn health in low- and middle-income countries during the last 15 years.
This ...systematic review consolidates evidence from seven published systematic reviews on the effects of different types of cash transfers and vouchers on the use and quality of maternity care services, and updates the systematic searches to June 2015 using the Joanna Briggs Institute approach for systematic reviewing. The review protocol for this update was registered with PROSPERO (CRD42015020637).
Data from 51 studies (15 more than previous reviews) and 22 cash transfer and voucher programmes suggest that approaches tied to service use (either via payment conditionalities or vouchers for selected services) can increase use of antenatal care, use of a skilled attendant at birth and in the case of vouchers, postnatal care too. The strongest evidence of positive effect was for conditional cash transfers and uptake of antenatal care, and for vouchers for maternity care services and birth with a skilled birth attendant. However, effects appear to be shaped by a complex set of social and healthcare system barriers and facilitators. Studies have typically focused on an initial programme period, usually two or three years after initiation, and many lack a counterfactual comparison with supply-side investment. There are few studies to indicate that programmes have led to improvements in quality of maternity care or maternal and newborn health outcomes.
Future research should use multiple intervention arms to compare cost-effectiveness with similar investment in public services, and should look beyond short- to medium-term service utilisation by examining programme costs, longer-term effects on service utilisation and health outcomes, and the equity of those effects.
Plastic debris have been shown to degenerate to particle sizes that can be transported in air, water, and food. Small particles are documented to enter and exit our bodies and translocate to and from ...some internal organs. Health effects on respiratory, hepatic, immune, and gastrointestinal systems have been reported in humans and other mammals in response to elevated particle or fiber exposures. These health effects differed by plastic type and size, and there was evidence of dose response for a few health endpoints. We conducted a systematic word search and reviewed published literature to identify microplastic and nanoplastic studies that quantified exposure via the ingestion, inhalation, and subcutaneous absorption (not dermal) exposure pathways; identified translocation, internal dose, and associations with health effects and markers related to exposures to specific sizes and types of plastics. We identified the data gaps in relating exposure data to health effects and biomarkers, most notably the lack of characterization of plastic particles and fibers smaller than 10 μm in most media.
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•Humans are exposed to microplastics via ingestion, inhalation, and absorption.•There is little exposure information on nanoplastics and most foods.•There is evidence of uptake, absorption, translocation, and effect.•Impacts reported on the immune, respiratory, gastro-intestinal, and hepatic systems.•Effects and target organs are dependent on plastic type, size, and amount.
Environmental Dimensions of Migration Hunter, Lori M; Luna, Jessie K; Norton, Rachel M
Annual review of sociology,
08/2015, Letnik:
41, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Research on the environmental dimensions of human migration has made important strides in recent years. However, findings have been spread across multiple disciplines with wide-ranging methodologies ...and limited theoretical development. This article reviews key findings of the field and identifies future directions for sociological research. We contend that the field has moved beyond linear environmental "push" theories toward a greater integration of context, including micro-level, meso-level, and macro-level interactions. We highlight findings that migration is often a household strategy to diversify risk (new economics of labor migration theory), interacting with household composition; individual characteristics; social networks; and historical, political, and economic contexts. We highlight promising developments in the field, including the recognition that migration is a long-standing form of environmental adaptation and yet only one among many forms of adaptation. Finally, we argue that sociologists could contribute significantly to migration-environment inquiry through attention to issues of inequality, perceptions, and agency vis-à-vis structure.
A panel of clinician scientists with expertise in neuromuscular blockade (NMB) monitoring was convened with a charge to prepare a consensus statement on indications for and proper use of such ...monitors. The aims of this article are to: (a) provide the rationale and scientific basis for the use of quantitative NMB monitoring; (b) offer a set of recommendations for quantitative NMB monitoring standards; (c) specify educational goals; and (d) propose training recommendations to ensure proper neuromuscular monitoring and management. The panel believes that whenever a neuromuscular blocker is administered, neuromuscular function must be monitored by observing the evoked muscular response to peripheral nerve stimulation. Ideally, this should be done at the hand muscles (not the facial muscles) with a quantitative (objective) monitor. Objective monitoring (documentation of train-of-four ratio ≥0.90) is the only method of assuring that satisfactory recovery of neuromuscular function has taken place. The panel also recommends that subjective evaluation of the responses to train-of-four stimulation (when using a peripheral nerve stimulator) or clinical tests of recovery from NMB (such as the 5-second head lift) should be abandoned in favor of objective monitoring. During an interim period for establishing these recommendations, if only a peripheral nerve stimulator is available, its use should be mandatory in any patient receiving a neuromuscular blocking drug. The panel acknowledges that publishing this statement per se will not result in its spontaneous acceptance, adherence to its recommendations, or change in routine practice. Implementation of objective monitoring will likely require professional societies and anesthesia department leadership to champion its use to change anesthesia practitioner behavior.
Dyslipidaemia is characterized by increased blood levels of total or LDL cholesterol and triglycerides, or decreased HDL cholesterol levels, and is a risk factor for cardiovascular disease. ...Dyslipidaemia has a high worldwide prevalence, and many patients are turning to alternatives to pharmacotherapy to manage their lipid levels. Lifestyle modification should be emphasized in all patients to reduce cardiovascular risk and can be initiated before pharmacotherapy in primary prevention of cardiovascular disease. Many functional foods and natural health products have been investigated for potential lipid-lowering properties. Those with good evidence for a biochemical effect on plasma lipid levels include soy protein, green tea, plant sterols, probiotic yogurt, marine-derived omega-3 fatty acids and red yeast rice. Other products such as seaweed, berberine, hawthorn and garlic might confer some limited benefit in certain patient groups. Although none of these products can reduce lipid levels to the same extent as statins, most are safe to use in addition to other lifestyle modifications and pharmacotherapy. Natural health products marketed at individuals with dyslipidaemia, such as policosanol, guggulsterone and resveratrol, have minimal definitive evidence of a biochemical benefit. Additional research is required in this field, which should include large, high-quality randomized controlled trials with long follow-up periods to investigate associations with cardiovascular end points.
Please cite this paper as: Hunter M, Gentry‐Maharaj A, Ryan A, Burnell M, Lanceley A, Fraser L, Jacobs I, Menon U. Prevalence, frequency and problem rating of hot flushes persist in older ...postmenopausal women: impact of age, body mass index, hysterectomy, hormone therapy use, lifestyle and mood in a cross‐sectional cohort study of 10 418 British women aged 54–65. BJOG 2012;119:40–50.
Objective Hot flushes and night sweats (HFs/NSs) are the main menopausal symptoms, but few studies have been adequately powered to examine the dimensions or predictors of experiencing HFs/NSs. We report on these variables in a large UK cohort of postmenopausal women.
Design Cross‐sectional cohort study.
Setting UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) cohort.
Population A cohort of 202 638 postmenopausal women, aged 50–74 years, without oophorectomy, recruited to UKCTOCS between 2001 and 2005.
Methods Women completed a follow‐up questionnaire, and those aged 54–65 years were mailed a survey in July 2008.
Main outcome measures Hot flush prevalence and hot flush rating scale.
Results Of the 15 000 women mailed, 10 418 returned completed questionnaires; 90% had previously had HFs/NSs. Despite being on average 10 years postmenopausal, 54% experienced HFs/NSs (frequency of 33 per week with mean problem rating 4/10) that persisted across the age range. Past hysterectomy (OR 1.50, 95% CI 1.19–1.86), ever having smoked (OR 1.27, 95% CI 1.11–1.46) and alcohol consumption (current units) (OR 1.05, 95% CI 1.01–1.09) predicted ever having had HFs/NSs. Anxiety (OR 3.09, 95% CI 2.57–3.72), hysterectomy (OR 2.74, 95% CI 2.32–3.25), depressed mood (OR 1.57, 95% CI 1.24–1.99), years since last menstrual period (OR 0.95, 95% CI 0.94–0.96) and education (above and below 18 years) (OR 0.98, 95% CI 0.97–0.99) predicted the current prevalence of HFs/NSs. Few predictors of frequency were identified, but problem rating was associated with depressed mood, hysterectomy, skirt size increase and frequency of HFs/NSs. Past hormone therapy users who had discontinued treatment were more likely to have HFs/NSs that were more frequent and problematic.
Conclusions To date, this is the largest UK study of the experience of HFs/NSs amongst older postmenopausal women. HFs/NSs are more prevalent in this age band than has previously been assumed. These findings and the associations of smoking, hysterectomy, anxiety, depressed mood and hormone therapy use with the experience of HFs/NSs have implications for prevention and symptom management.
Water in confinement exhibits properties significantly different from bulk water due to frustration in the hydrogen-bond network induced by interactions with the substrate. Here, we combine infrared ...spectroscopy and many-body molecular dynamics simulations to probe the structure and dynamics of confined water as a function of relative humidity within a metal-organic framework containing cylindrical pores lined with ordered cobalt open coordination sites. Building upon the agreement between experimental and theoretical spectra, we demonstrate that water at low relative humidity binds initially to open metal sites and subsequently forms disconnected one-dimensional chains of hydrogen-bonded water molecules bridging between cobalt atoms. With increasing relative humidity, these water chains nucleate pore filling, and water molecules occupy the entire pore interior before the relative humidity reaches 30%. Systematic analysis of rotational and translational dynamics indicates heterogeneity in this pore-confined water, with water molecules displaying variable mobility as a function of distance from the interface.
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