Environmental controls on microbial abundance and activity on the greenland ice sheet: a multivariate analysis approach.

Microbes in supraglacial ecosystems have been proposed to be significant contributors to regional and possibly global carbon cycling, and quantifying the biogeochemical cycling of carbon in glacial ecosystems is of great significance for global carbon flow estimations. Here we present data on microbial abundance and productivity, collected along a transect across the ablation zone of the Greenland ice sheet (GrIS) in summer 2010. We analyse the relationships between the physical, chemical and biological variables using multivariate statistical analysis. Concentrations of debris-bound nutrients increased with distance from the ice sheet margin, as did both cell numbers and activity rates before reaching a peak (photosynthesis) or a plateau (respiration, abundance) between 10 and 20 km from the margin. The results of productivity measurements suggest an overall net autotrophy on the GrIS and support the proposed role of ice sheet ecosystems in carbon cycling as regional sinks of CO(2) and places of production of organic matter that can be a potential source of nutrients for downstream ecosystems. Principal component analysis based on chemical and biological data revealed three clusters of sites, corresponding to three 'glacier ecological zones', confirmed by a redundancy analysis (RDA) using physical data as predictors. RDA using data from the largest 'bare ice zone' showed that glacier surface slope, a proxy for melt water flow, accounted for most of the variation in the data. Variation in the chemical data was fully explainable by the determined physical variables. Abundance of phototrophic microbes and their proportion in the community were identified as significant controls of the carbon cycling-related microbial processes.

The relation of diabetes, impaired fasting blood glucose, and insulin resistance to left ventricular structure and function in African Americans: the Jackson Heart Study.

OBJECTIVE: We assessed the relation of diabetes and insulin resistance (IR) on left ventricular (LV) structure and function in African Americans. RESEARCH DESIGN AND METHODS: Among those receiving echocardiograms in cycle 1 of the Jackson Heart Study, we assessed the sex-specific relation of fasting blood glucose (FBG), diabetes, and IR to LV structure and function, adjusting for age, systolic blood pressure, antihypertensive medications, and BMI. RESULTS: Among 2,399 participants, LV mass index (P(women) = 0.0002 and P(men) = 0.02), posterior wall thickness (P(women) = 0.01 and P(men) = 0.05), and interventricular septal wall thickness (P(women) = 0.01) were related to FBG categories. Among those with normal FBG and no diabetes, concentric remodeling and low ejection fraction in women and LV mass index and posterior wall thickness in men were related to IR. CONCLUSIONS: In the largest study of its kind in a community-based cohort of African Americans, we found a relation of FBG category and IR to LV structure and function.

Private demand for cholera vaccines in Hue, Vietnam.

OBJECTIVES: This study aims to measure the private demand for oral cholera vaccines in Hue, Vietnam, an area of relatively low endemicity of cholera, using the contingent valuation method. METHODS: Interviews were conducted with either the head of household or spouse in 800 randomly selected households with children less than 18 years old. Respondents were asked whether they would purchase an oral cholera vaccine with different levels of effectiveness and durations of effectiveness (both for themselves and for other household members) at a specified price. RESULTS: The median respondent willingness to pay for 50% effective/3-year vaccine was estimated to be approximately $5, although 17% of the study sample would not pay for a cholera vaccine. The median economic benefit to a household of vaccinating all household members against cholera, as measured by its stated willingness to pay, was estimated to be $40 for a vaccine with these attributes. CONCLUSIONS: The perceived private economic benefits of a cholera vaccine were high, but not evenly distributed across the population. A minority of the people in Hue place no value on receiving a cholera vaccine.