Predicting the effects of climate change on water yield and forest production in the northeastern United States

Rapid and simultaneous changes in temperature, precipitation and the atmospheric concentration of CO2 are predicted to occur over the next century. Simple, well-validated models of ecosystem function are required to predict the effects of these changes. This paper describes an improved version of a forest carbon and water balance model (PnET-II) and the application of the model to predict stand- and regional-level effects of changes in temperature, precipitation and atmospheric CO2 concentration. PnET-II is a simple, generalized, monthly time-step model of water and carbon balances (gross and net) driven by nitrogen availability as expressed through foliar N concentration. Improvements from the original model include a complete carbon balance and improvements in the prediction of canopy phenology, as well as in the computation of canopy structure and photosynthesis. The model was parameterized and run for 4 forest/site combinations and validated against available data for water yield, gross and net carbon exchange and biomass production. The validation exercise suggests that the determination of actual water availability to stands and the occurrence or non-occurrence of soil-based water stress are critical to accurate modeling of forest net primary production (NPP) and net ecosystem production (NEP). The model was then run for the entire NewEngland/New York (USA) region using a 1 km resolution geographic information system. Predicted long-term NEP ranged from -85 to +275 g C m-2 yr-1 for the 4 forest/site combinations, and from -150 to 350 g C m-2 yr-1 for the region, with a regional average of 76 g C m-2 yr-1. A combination of increased temperature (+6*C), decreased precipitation (-15%) and increased water use efficiency (2x, due to doubling of CO2) resulted generally in increases in NPP and decreases in water yield over the region

Fluconazole Prophylaxis for the Prevention of Candidiasis in Premature Infants: A Meta-analysis Using Patient-level Data

Background. Invasive candidiasis (IC) is an important cause of sepsis in premature infants and is associated with a high risk of death and neurodevelopmental impairment. Prevention of IC has become a major focus in very low birth weight infants, with fluconazole increasingly used as prophylaxis. Methods. We identified all randomized, placebo-controlled trials evaluating fluconazole prophylaxis in premature infants conducted in the United States. We obtained patient-level data from the study investigators and performed an aggregated analysis. The occurrence of each endpoint in infants who received prophylaxis with fluconazole vs placebo was compared. Endpoints evaluated were IC or death, IC, death, Candida colonization, and fluconazole resistance among tested isolates. Safety endpoints evaluated included clinical and laboratory parameters. Results. Fluconazole prophylaxis reduced the odds of IC or death, IC, and Candida colonization during the drug exposure period compared with infants given placebo: odds ratios of 0.48 (95% confidence interval [CI], .30-.78), 0.20 (95% CI, .08-.51), and 0.28 (95% CI, .18-.41), respectively. The incidence of clinical and laboratory adverse events was similar for infants who received fluconazole compared with placebo. There was no statistically significant difference in the proportion of tested isolates that were resistant to fluconazole between the fluconazole and placebo groups. Conclusions. Fluconazole prophylaxis is effective and safe in reducing IC and Candida colonization in premature infants, and has no impact on resistance.National Institute of Child Health and Human Development (NICHD) [HHSN275201000003I]National Center for Advancing Translational Sciences (NCATS) of the National Institutes of Health (NIH) [ULITR001117]NICHD [HHSN275201000003I, 5T32HD060558, 1R01-HD081044-01]NIH [HHSN275201000003I, ULITR001117, 2K24HD058735-06, HHSN272201500006I]NCATS of the NIH [ULITR001117]US Food and Drug Administration [1R18-FD005292-01]Penn State Coll Med, Dept Pediat, Hershey, PA USAUniv Virginia, Dept Pediat, Charlottesville, VA USAWake Med Ctr, Raleigh, NC USAGeorgia Regents Univ, Dept Pediat, Augusta, GA USAUniv Fed Sao Paulo, Escola Paulista Med, Sao Paulo, BrazilDuke Clin Res Inst, 2400 Pratt St, Durham, NC 27705 USADuke Univ, Sch Med, Dept Pediat, Durham, NC USAUniv Fed Sao Paulo, Escola Paulista Med, Sao Paulo, BrazilNICHD:HHSN275201000003NIH:ULITR001117NICHD:HHSN275201000003I5T32HD0605581R01-HD081044-01NIH:HHSN275201000003IULITR0011172K24HD058735-06HHSN272201500006I]|NIH:ULITR001117FDA:1R18-FD005292-01Web of Scienc

Global climate change and soil carbon stocks: predictions from two contrasting models for the turnover of organic carbon in soil

Enhanced release of CO2 to the atmosphere from soil organic carbon as a result of increased temperatures may lead to a positive feedback between climate change and the carbon cycle, resulting in much higher CO2 levels and accelerated lobal warming. However, the magnitude of this effect is uncertain and critically dependent on how the decomposition of soil organic C (heterotrophic respiration) responds to changes in climate. Previous studies with the Hadley Centre’s coupled climate–carbon cycle general circulation model (GCM) (HadCM3LC) used a simple, single-pool soil carbon model to simulate the response. Here we present results from numerical simulations that use the more sophisticated ‘RothC’ multipool soil carbon model, driven with the same climate data. The results show strong similarities in the behaviour of the two models, although RothC tends to simulate slightly smaller changes in global soil carbon stocks for the same forcing. RothC simulates global soil carbon stocks decreasing by 54 GtC by 2100 in a climate change simulation compared with an 80 GtC decrease in HadCM3LC. The multipool carbon dynamics of RothC cause it to exhibit a slower magnitude of transient response to both increased organic carbon inputs and changes in climate. We conclude that the projection of a positive feedback between climate and carbon cycle is robust, but the magnitude of the feedback is dependent on the structure of the soil carbon model

Methods for isolation, purification and structural elucidation of bioactive secondary metabolites from marine invertebrates

In the past few decades, marine natural products bioprospecting has yielded a considerable number of drug candidates. Two marine natural products have recently been admitted as new drugs: Prialt (also known as ziconotide) as a potent analgesic for severe chronic pain and Yondelis (known also as trabectedin or E-743) as antitumor agent for the treatment of advanced soft tissue sarcoma. In this protocol, methods for bioactivity-guided isolation, purification and identification of secondary metabolites from marine invertebrates such as sponges, tunicates, soft corals and crinoids are discussed. To achieve this goal, solvent extraction of usually freeze-dried sample of marine organisms is performed. Next, the extract obtained is fractionated by liquid-liquid partitioning followed by various chromatographic separation techniques including thin layer chromatography, vacuum liquid chromatography, column chromatography (CC) and preparative high-performance reversed-phase liquid chromatography. Isolation of bioactive secondary metabolites is usually monitored by bioactivity assays, e.g., antioxidant (2,2-diphenyl-1-picryl hydrazyl) and cytotoxicity (microculture tetrazolium) activities that ultimately yield the active principles. Special care should be taken when performing isolation procedures adapted to the physical and chemical characteristics of the compounds isolated, particularly their lipo- or hydrophilic characters. Examples of isolation of compounds of different polarities from extracts of various marine invertebrates will be presented in this protocol. Structure elucidation is achieved using recent spectroscopic techniques, especially 2D NMR and mass spectrometry analysis

The Prevalence of Limited Health Literacy

OBJECTIVE: To systematically review U.S. studies examining the prevalence of limited health literacy and to synthesize these findings by evaluating demographic associations in pooled analyses. DESIGN: We searched the literature for the period 1963 through January 2004 and identified 2,132 references related to a set of specified search terms. Of the 134 articles and published abstracts retrieved, 85 met inclusion criteria, which were 1) conducted in the United States with ≥25 adults, 2) addressed a hypothesis related to health care, 3) identified a measurement instrument, and 4) presented primary data. The authors extracted data to compare studies by population, methods, and results. MAIN RESULTS: The 85 studies reviewed include data on 31,129 subjects, and report a prevalence of low health literacy between 0% and 68%. Pooled analyses of these data reveal that the weighted prevalence of low health literacy was 26% (95% confidence interval [CI], 22% to 29%) and of marginal health literacy was 20% (95% CI, 16% to 23%). Most studies used either the Rapid Estimate of Adult Literacy in Medicine (REALM) or versions of the Test of Functional Health Literacy in Adults (TOFHLA). The prevalence of low health literacy was not associated with gender (P =.38) or measurement instrument (P =.23) but was associated with level of education (P =.02), ethnicity (P =.0003), and age (P =.004). CONCLUSIONS: A pooled analysis of published reports on health literacy cannot provide a nationally representative prevalence estimate. This systematic review exhibits that limited health literacy, as depicted in the medical literature, is prevalent and is consistently associated with education, ethnicity, and age. It is essential to simplify health services and improve health education. Such changes have the potential to improve the health of Americans and address the health disparities that exist today

Climate-sensitive northern lakes and ponds are critical components of methane release

Lakes and ponds represent one of the largest natural sources of the greenhouse gas methane. By surface area, almost half of these waters are located in the boreal region and northwards. A synthesis of measurements of methane emissions from 733 lakes and ponds north of ∼50° N, combined with new inventories of inland waters, reveals that emissions from these high latitudes amount to around 16.5 Tg CH4 yr−1 (12.4 Tg CH4-C yr−1). This estimate — from lakes and ponds alone — is equivalent to roughly two-thirds of the inverse model calculation of all natural methane sources in the region. Thermokarst water bodies have received attention for their high emission rates, but we find that post-glacial lakes are a larger regional source due to their larger areal extent. Water body depth, sediment type and ecoclimatic region are also important in explaining variation in methane fluxes. Depending on whether warming and permafrost thaw cause expansion or contraction of lake and pond areal coverage, we estimate that annual water body emissions will increase by 20–54% before the end of the century if ice-free seasons are extended by 20 days. We conclude that lakes and ponds are a dominant methane source at high northern latitudes