Linking physiological rates and community ecology: effects of ocean temperature on dispersal and species interactions

Our ability to predict and manage ecological change in the face of climate warming requires an understanding of the influence of climate on critical demographic and community-level processes. In spite of a rich history of research on ecological processes and the patterns they create, responses to climate change have been interpreted as species-specific, such as shifts in geographic ranges and the timing of seasonal life cycle events. However, recently described general and predictable responses of organisms to non-lethal changes in temperature may provide an important mechanistic link between local climate conditions and ecological processes. I have applied the metabolic theory of ecology to dispersal and food web dynamics to test the effect of temperature on complex, community-structuring processes. I used statistical and theoretical models to determine the generality of the effect of temperature on larval development and dispersal, and to consider consequences for biogeographic patterns, population connectivity and conservation. Using experiments, I tested the effect of temperature on herbivore-plant interaction strength, food web structure and production. Results show that general effects of temperature on fundamental metabolic components are consistent with community level responses to changing temperature, and these effects may provide a mechanistic explanation for broad biogeographic patterns and marine ecosystem response to climate change

Distribution of energy intake across the day and weight loss : a systematic review and meta-analysis

ACKNOWLEDGMENT The authors would like to thank Ms Kanchana Ekanayake (Health Sciences Library, The University of Sydney) for her invaluable assistance with the literature searches. Open access publishing facilitated by The University of Sydney, as part of the Wiley - The University of Sydney agreement via the Council of Australian University Librarians.Peer reviewedPublisher PD

Avaliação da homogeneidade da dieta completa (unifeed) para vacas leiteiras

Mestrado em Engenharia Zootécnica - Produção Animal - Instituto Superior de Agronomia / Faculdade de Medicina VeterináriaThe feed management is very important in animal nutrition, specifically in farm animals. The diet supplements usually associated with high milk yield of cows is often used also by the ease of their management. This work studied the homogeneity of the TMR designed for Holstein dairy cows using an horizontal mixer wagon, by chemical composition (DM, CP, NDF, ADF and ADL) and particle size (sieve with 19, 8, 1 mm and bottom) to ensure that meets their nutritional needs. Also the nutritional parameters (DM, CP, NDF, ADF and ADL) were studied for the feed constituents in the diet: corn silage, alfalfa hay, tomato pomace and compound feed. For this study feed from 3 pens which contain the same diet consisting for 226 cows was analyzed. Samples of the diet were taken in for 4 days (not consecutive) in the beginning and end of each pen, while in the pen 2 and 3 were also sampled in the middle, after distribution of the morning diet. On the chemical composition of the diet, there are only significant variations in levels of DM and ADL, taking into account the day of trial, without these differences result in bad diets formulated or processed. These changes may be due to the quantity of tomato incorporated in the diet (high moisture). Compared to the previously formulated diet, the results indicate that the DM and CP are slightly lower; the values proposed by NRC (2001) for NDF are below the values obtained, while the percentage of ADF is in agreement with the expected. On the study of the ingredients of the diet, there are specific nutritional differences compared with reference values, but in a general rule, feeds in the diet for the parameters under study are within the specified limits. The results of the particle size of the diet showed significant differences in all size classes for the days of testing, including also the particles between 1 to 8 mm in view of the pens of the test. In D1, the percentage of particles between 1 to 8 mm is higher than expected, with other classes within the size limits. The reduction of particles retained in sieve of 8 mm, and an increase in the sieve of 1 mm in D2, can be explain by the mixing time practiced. Overall, the proportion of particles 8-19 mm were under and particles 1-8 mm were above the recommended values. In the last day of testing, the higher processing time of the forage may have led to reduction of particles with size > 19 mm, leading to only the particles < 1 mm were in appropriate proportions. The differences occurred between pens were small and could be a consequence of the distance between pens and the path irregular used by SRMDR.On average the size fractions ranging from 1 to 8 mm to 19 mm and 8 are not inagreement with the expected. The particles retained in sieve of 1 mm are at higher percentage, whereas fractions retained in the sieve with 8 mm are lower.-------------------------------------A dieta completa (MS=53,3%, PB=27,4%) foi formulada de modo a cobrir as exigências nutricionais de vacas Holstein que produzem em média 25,8 kg de leite por dia. Com o objectivo de avaliar a homogeneidade da dieta completa, quer em termos de composição química quer de granulometria, foram recolhidas 8 amostras de alimento ao longo das manjedouras em 4 dias, perfazendo na totalidade 32 amostras. Cada amostra foi sujeita à determinação da composição química (MS, PB, NDF, ADF e ADL) e à avaliação da granulometria usando um ‘Penn State Particle Separator’ (PSPS) composto por 3 crivos (diâmetro com 19, 8 e 1 mm) e um fundo. Foi também analisado cada alimento da dieta individualmente (MS, PB, NDF, ADF e ADL). A composição química verificou-se homogénea ao longo do ensaio, apesar das pequenas alterações no teor de MS e de ADL, para os dias de ensaio, embora irrelevantes. Verificouse um efeito importante do dia de recolha na granulometria da dieta, mas a diferença entre parques foi pequena

Microbiological effects of an antiseptic mouthrinse in irradiated cancer patients

Objective: To assess the microbiological effects of an antiseptic, non-alcohol based mouth-rinse containing chlorhexidine and cetylpyridinium chloride, in patients undergoing radiation therapy for head-and-neck cancer. Study Design: This was a parallel, double-blind, prospective, randomized clinical trial, including patients irradiated as part of the therapy of head-and-neck cancer, aged 18-75, with at least 10 teeth, and willing to sign an informed consent. Cancer patients were randomly assigned to one of the two treatments (test mouth-rinse or a placebo). Three visits were scheduled (baseline, 14 and 28 days). Microbiological findings were evaluated in tongue, mucosa and subgingival samples, by means of culture. Microbiological variables were assessed by means of the Mann-Whitney, Wilcoxon and chi-square tests. Results: 70 patients were screened and 36 were included. The detection of Candida species in mucosa and tongue samples showed significant reductions in the test group. Total bacterial counts decreased in both groups from baseline to the 2-week visit, while minor changes occurred between 2 and 4 weeks (effects on P. gingivalis, P. intermedia, C. rectus, E. corrodens). Conclusions: Within the limitations of the small sample size, this study suggests that the use of the tested mouth-rinse may lead to improvements in microbiological parameters in patients irradiated for head-and-neck cancer. © Medicina Oral S. L

Mucositis in irradiated cancer patients : effects of an antiseptic mouthrinse

Objective: To assess the effects of an antiseptic, non-alcohol based mouth-rinse containing chlorhexidine and cetylpyridinium chloride, in preventing the oral complications associated to radiation therapy in head-and-neck cancer patients. Study design: This was a parallel, double blind, prospective, randomized clinical trial. Cancer patients were randomly assigned to one of the two treatments (test mouth-rinse or a placebo). Three visits were scheduled (baseline, 14 and 28 days). Different outcome variables were evaluated: mucositis, plaque and gingival indices, stimulated saliva and salivary pH. Results: 70 patients were screened and 36 were included. The presence and the degree of mucositis significantly increased in both groups and no significant differences were detected between groups, although the median increase in the placebo group (1.81) at 2 weeks was higher than in the test group (1.20). Conclusions: Within the limitations of the small sample size, this study suggests that the use of the tested mouthrinse may lead to some improvements in clinical parameters in patients irradiated for head-and-neck cancer

Death Dilemma and Organism Recovery in Ecotoxicology

Why do some individuals survive after exposure to chemicals while others die? Either, the tolerance threshold is distributed among the individuals in a population, and its exceedance leads to certain death, or all individuals share the same threshold above which death occurs stochastically. The previously published General Unified Threshold model of Survival (GUTS) established a mathematical relationship between the two assumptions. According to this model stochastic death would result in systematically faster compensation and damage repair mechanisms than individual tolerance. Thus, we face a circular conclusion dilemma because inference about the death mechanism is inherently linked to the speed of damage recovery. We provide empirical evidence that the stochastic death model consistently infers much faster toxicodynamic recovery than the individual tolerance model. Survival data can be explained by either, slower damage recovery and a wider individual tolerance distribution, or faster damage recovery paired with a narrow tolerance distribution. The toxicodynamic model parameters exhibited meaningful patterns in chemical space, which is why we suggest toxicodynamic model parameters as novel phenotypic anchors for in vitro to in vivo toxicity extrapolation. GUTS appears to be a promising refinement of traditional survival curve analysis and dose response models

Risk mitigation measures for pesticide runoff: How effective are they?

BACKGROUND: One of the most important sources of pesticide pollution of surface waters is runoff and erosion from agricultural fields after rainfall. This study analyses the efficacy of different risk mitigation measures to reduce pesticide runoff and erosion inputs into surface waters from arable land excluding rice fields. RESULTS: Three groups of risk mitigation measures were quantitatively analyzed: vegetative filter strips, micro-dams in row crops and soil conservation measures. Their effectiveness was evaluated based on a meta-analysis of available experimental data using statistical methods such as classification and regression trees, and exploratory data analysis. Results confirmed the effectiveness of vegetative filter strips and micro-dams. Contrary to common assumption, the width of vegetative filter strips alone is not sufficient to predict their effectiveness. The effectiveness of soil conservation measures (especially mulch-tillage) varied widely. This was in part due to the heterogeneity of the available experimental data, probably resulting from the inconsistent implementation and the inadequate definitions of these measures. CONCLUSION: Both vegetative filter strips and micro-dams are effective and suitable, and can therefore be recommended for quantitative assessment of environmental pesticide exposure in surface waters.However, the processes of infiltration and sedimentation in vegetative filter strips should be simulated with amechanistic model like Vegetative Filter Strip Modeling System, VFSMOD. The reduction effect ofmicro-dams can be modelled by reducing the runoff curve number, e.g., in the pesticide root zone model, PRZM. Soil conservationmeasures are in principle promising, but further well-documented data are needed to determine under which conditions they are effective

CH-01 is a hypoxia-activated prodrug that sensitizes cells to hypoxia/reoxygenation through inhibition of Chk1 and aurora A

The increased resistance of hypoxic cells to all forms of cancer therapy presents a major barrier to the successful treatment of most solid tumors. Inhibition of the essential kinase Checkpoint kinase 1 (Chk1) has been described as a promising cancer therapy for tumors with high levels of hypoxia-induced replication stress. However, as inhibition of Chk1 affects normal replication and induces DNA damage, these agents also have the potential to induce genomic instability and contribute to tumorigenesis. To overcome this problem, we have developed a bioreductive prodrug, which functions as a Chk1/Aurora A inhibitor specifically in hypoxic conditions. To achieve this activity, a key functionality on the Chk1 inhibitor (CH-01) is masked by a bioreductive group, rendering the compound inactive as a Chk1/Aurora A inhibitor. Reduction of the bioreductive group nitro moiety, under hypoxic conditions, reveals an electron-donating substituent that leads to fragmentation of the molecule, affording the active inhibitor. Most importantly, we show a significant loss of viability in cancer cell lines exposed to hypoxia in the presence of CH-01. This novel approach targets the most aggressive and therapy-resistant tumor fraction while protecting normal tissue from therapy-induced genomic instability. © 2013 American Chemical Society