Mercury dynamics in the pore water of peat columns during experimental freezing and thawing.

Biogeochemical processes in northern peatland ecosystems are influenced by seasonal temperature fluctuations that are changing with the climate. Methylmercury (MeHg), commonly produced in peatlands, affects downstream waters; therefore, it is important to understand how temperature transitions affect mercury (Hg) dynamics. We investigated how the freeze-thaw cycle influences belowground peat pore water total Hg (THg), MeHg, and dissolved organic carbon (DOC).

Acetazolamide and N-acetylcysteine in the treatment of chronic mountain sickness (Monge's disease).

Patients suffering from chronic mountain sickness (CMS) have excessive erythrocytosis. Low -level cobalt toxicity as a likely contributor has been demonstrated in some subjects. We performed a randomized, placebo controlled clinical trial in Cerro de Pasco, Peru (4380m), where 84 participants with a hematocrit (HCT) ≥65% and CMS score>6, were assigned to four treatment groups of placebo, acetazolamide (ACZ, which stimulates respiration), N-acetylcysteine (NAC, an antioxidant that chelates cobalt) and combination of ACZ and NAC for 6 weeks.

Quantifying the associations between fungal endophytes and biocontrol-induced herbivory of invasive purple loosestrife (Lythrum salicaria L.).

Fungal endophytes are one of several groups of heterotrophic organisms that associate with living plants. The net effects of these groups of organisms on each other and ultimately on their host plants depend in part on how they facilitate or antagonize one another. In this study we quantified the associations between endophyte communities and herbivory induced by a biological control in the invasive Lythrum salicaria at various spatial scales using a culture-based approach.

Serum uric acid and hypertension in adults: a paradoxical relationship in type 1 diabetes.

Adults with type 1 diabetes have lower serum uric acid levels compared with nondiabetic adults. Little is known about the relationship between serum uric acid and blood pressure in type 1 diabetes and whether it differs from the positive relationship found in nondiabetic adults. The authors assessed the cross-sectional and longitudinal relationships over 6 years between serum uric acid and blood pressure in adults with (35±9 years [n=393]) and without (38±9 years [n=685]) type 1 diabetes in the Coronary Artery Calcification in Type 1 Diabetes study.

Organic-matter loading determines regime shifts and alternative states in an aquatic ecosystem.

Slow changes in underlying state variables can lead to "tipping points," rapid transitions between alternative states ("regime shifts") in a wide range of complex systems. Tipping points and regime shifts routinely are documented retrospectively in long time series of observational data. Experimental induction of tipping points and regime shifts is rare, but could lead to new methods for detecting impending tipping points and forestalling regime shifts.