Does soil pyrogenic carbon determine plant functional traits in Amazon Basin forests?

Amazon forests are fire-sensitive ecosystems and consequently fires affect forest structure and composition. For instance, the legacy of past fire regimes may persist through some species and traits that are found due to past fires. In this study, we tested for relationships between functional traits that are classically presented as the main components of plant ecological strategies and environmental filters related to climate and historical fires among permanent mature forest plots across the range of local and regional environmental gradients that occur in Amazonia. We used percentage surface soil pyrogenic carbon (PyC), a recalcitrant form of carbon that can persist for millennia in soils, as a novel indicator of historical fire in old-growth forests. Five out of the nine functional traits evaluated across all 378 species were correlated with some environmental variables. Although there is more PyC in Amazonian soils than previously reported, the percentage soil PyC indicated no detectable legacy effect of past fires on contemporary functional composition. More species with dry diaspores were found in drier and hotter environments. We also found higher wood density in trees from higher temperature sites. If Amazon forest past burnings were local and without distinguishable attributes of a widespread fire regime, then impacts on biodiversity would have been small and heterogeneous. Alternatively, sufficient time may have passed since the last fire to allow for species replacement. Regardless, as we failed to detect any impact of past fire on present forest functional composition, if our plots are representative then it suggests that mature Amazon forests lack a compositional legacy of past fire

A next-generation liquid xenon observatory for dark matter and neutrino physics

The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector

Postoperative atrial fibrillation and total dietary antioxidant capacity in patients undergoing cardiac surgery: The Polyphemus Observational Study

Objective: Postoperative atrial fibrillation is a major cause of morbidity and mortality for stroke after cardiac surgery. Both systemic inflammation and oxidative stress play a role in the initiation of postoperative atrial fibrillation after cardiac surgery. The possible association between long-term intake of antioxidant-rich foods and postoperative atrial fibrillation incidence was examined in patients undergoing cardiac surgery. Methods: A total of 217 consecutive patients (74% were men; median age, 68.4 years) undergoing cardiac surgery, mainly coronary artery bypass grafting and valve replacement or repair, were recruited from January 2010 to September 2012. Total antioxidant capacity was measured in foods by the Trolox equivalent antioxidant capacity assay. The European Prospective Investigation into Cancer and Nutrition Food Frequency Questionnaire was used for dietary total antioxidant capacity assessment. The association among tertiles of dietary total antioxidant capacity and postoperative atrial fibrillation incidence was assessed using multivariable logistic analysis. Results: The overall incidence of total arrhythmias and postoperative atrial fibrillation was 42.4% and 38.2%, respectively. Inmultivariable analysis, after adjustment for age, gender, use of hypoglycemic drugs, physical activity, education, previous diagnosis of atrial fibrillation, and total energy intake, patients in the highest tertile of dietary total antioxidant capacity had a lower risk of postoperative atrial fibrillation than patients in the 2 lowest tertiles (odds ratio, 0.46; 95% confidence interval, 0.22-0.95; P = .048). Arestricted cubic spline transformation confirmed the nonlinear relationship between total antioxidant capacity (in continuous scale) and postoperative atrial fibrillation (P = .023). When considering only coronary artery bypass grafting, valve replacement/repair, and combined surgeries, the protective effect on postoperative atrial fibrillation of a diet rich in antioxidants was confirmed. Conclusions: Long-term consumption of antioxidant-rich foods is associated with a reduced incidence of postoperative atrial fibrillation in patients undergoing cardiac surgery

Trophic ecology of two savanna grazers, blue wildebeest Connochaetes taurinus and black wildebeest Connochaetes gnou

The feeding niches and trophic ecology of two South African grazers, blue wildebeest Connochaetes taurinus and black wildebeest Connochaetes gnou, are compared using stable carbon and nitrogen isotope data from feces and tooth dentine collagen. As sympatric, closely related taxa predicted to occupy similar trophic positions, the blue and black wildebeest provide a good model for studying the mechanisms of coexistence and macroevolution in mammals. Data from feces collected from a single reserve in the Free State Province reveal different trophic behaviors between two herds of blue wildebeest and between both compared with a single herd of black wildebeest. These data suggest that sympatric coexistence of blue and black wildebeest is facilitated by differential niche occupation at family group or herd levels, rather than between species. However, such separation does not occur over longer time scales: results from dentine collagen support the hypothesis that the two species are indistinct in terms of trophic behavior, although blue wildebeest show more feeding flexibility, probably because of their wider habitat tolerance range. Similarities in premaxillary width of males and females of both species also suggest that both species are adapted to similar feeding styles. Thus, it is unlikely that changes in trophic behavior provided the trigger for divergence of the black from the blue wildebeest lineage in the Middle Pleistocene. We argue that the case of these two species represents an example of speciation that was not driven by resource competition, as is often assumed for many turnover events in mammalian evolution. We briefly discuss a previous suggestion that links black wildebeest evolution to their more territorial breeding behavior associated with Middleto-Late Pleistocene landscape changes in southern Africa

The Cloning and Expression of Human Monoclonal Antibodies:Implications for Allergen Immunotherapy

Allergic responses are dependent on the highly specific effector functions of IgE antibodies. Conversely, antibodies that block the activity of IgE can mediate tolerance to allergen. Technologies that harness the unparalleled specificity of antibody responses have revolutionized the way that we diagnose and treat human disease. This area of research continues to advance at a rapid pace and has had a significant impact on our understanding of allergic disease. This review will present an overview of humoral responses and provide an up-to-date summary of technologies used in the generation of human monoclonal antibodies. The impact that monoclonal antibodies have on allergic disease will be discussed, with a particular focus on allergen immunotherapy, which remains the only form of treatment that can modulate the underlying immune mechanisms and induce long-term clinical tolerance