Polychlorinated Biphenyls in Glaciers. 2. Model Results of Deposition and Incorporation Processes

In previous work, Alpine glaciers have been identified as a secondary source of persistent organic pollutants (POPs). However, detailed understanding of the processes organic chemicals undergo in a glacial system was missing. Here, we present results from a chemical fate model describing deposition and incorporation of polychlorinated biphenyls (PCBs) into an Alpine glacier (Fiescherhorn, Switzerland) and an Arctic glacier (Lomonosovfonna, Norway). To understand PCB fate and dynamics, we investigate the interaction of deposition, sorption to ice and particles in the atmosphere and within the glacier, revolatilization, diffusion and degradation, and discuss the effects of these processes on the fate of individual PCB congeners. The model is able to reproduce measured absolute concentrations in the two glaciers for most PCB congeners. While the model generally predicts concentration profiles peaking in the 1970s, in the measurements, this behavior can only be seen for higher-chlorinated PCB congeners on Fiescherhorn glacier. We suspect seasonal melt processes are disturbing the concentration profiles of the lower-chlorinated PCB congeners. While a lower-chlorinated PCB congener is mainly deposited by dry deposition and almost completely revolatilized after deposition, a higher-chlorinated PCB congener is predominantly transferred to the glacier surface by wet deposition and then is incorporated into the glacier ice. The incorporated amounts of PCBs are higher on the Alpine glacier than on the Arctic glacier due to the higher precipitation rate and aerosol particle concentration on the former. Future studies should include the effects of seasonal melt processes, calculate the quantities of PCBs incorporated into the entire glacier surface, and estimate the quantity of chemicals released from glaciers to determine the importance of glaciers as a secondary source of organic chemicals to remote aquatic ecosystems.

Extreme climatic events: impacts of drought and high temperature on physiological processes in agronomically important plants

Climate models predict more frequent and more severe extreme events (e.g., heat waves, extended drought periods, flooding) in many regions for the next decades. The impact of adverse environmental conditions on crop plants is ecologically and economically relevant. This review is focused on drought and heat effects on physiological status and productivity of agronomically important plants. Stomatal opening represents an important regulatory mechanism during drought and heat stress since it influences simultaneously water loss via transpiration and CO2 diffusion into the leaf apoplast which further is utilized in photosynthesis. Along with the reversible short-term control of stomatal opening, stomata and leaf epidermis may produce waxy deposits and irreversibly down-regulate the stomatal conductance and non-stomatal transpiration. As a consequence photosynthesis will be negatively affected. Rubisco activase—a key enzyme in keeping the Calvin cycle functional—is heat-sensitive and may become a limiting factor at elevated temperature. The accumulated reactive oxygen species (ROS) during stress represent an additional challenge under unfavorable conditions. Drought and heat cause accumulation of free amino acids which are partially converted into compatible solutes such as proline. This is accompanied by lower rates of both nitrate reduction and de novo amino acid biosynthesis. Protective proteins (e.g., dehydrins, chaperones, antioxidant enzymes or the key enzyme for proline biosynthesis) play an important role in leaves and may be present at higher levels under water deprivation or high temperatures. On the whole plant level, effects on long-distance translocation of solutes via xylem and phloem and on leaf senescence (e.g., anticipated, accelerated or delayed senescence) are important. The factors mentioned above are relevant for the overall performance of crops under drought and heat and must be considered for genotype selection and breeding programs.

Psychological interventions for acute pain after open heart surgery

BACKGROUND Acute postoperative pain is one of the most disturbing complaints in open heart surgery, and is associated with a risk of negative consequences. Several trials investigated the effects of psychological interventions to reduce acute postoperative pain and improve the course of physical and psychological recovery of participants undergoing open heart surgery. OBJECTIVES To compare the efficacy of psychological interventions as an adjunct to standard care versus standard care alone or standard care plus attention in adults undergoing open heart surgery on pain, pain medication, mental distress, mobility, and time to extubation. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 8), MEDLINE (1946 to September 2013), EMBASE (1980 to September 2013), Web of Science (all years to September 2013), and PsycINFO (all years to September 2013) for eligible studies. We used the 'related articles' and 'cited by' options of eligible studies to identify additional relevant studies. We also checked lists of references of relevant articles and previous reviews. We also searched the ProQuest Dissertations and Theses Full Text Database (all years to September 2013) and contacted the authors of primary studies to identify any unpublished material. SELECTION CRITERIA Randomised controlled trials comparing psychological interventions as an adjunct to standard care versus standard care alone or standard care plus attention in adults undergoing open heart surgery. DATA COLLECTION AND ANALYSIS Two review authors (SK and JR) independently assessed trials for eligibility, estimated the risk of bias and extracted all data. We calculated effect sizes for each comparison (Hedges' g) and meta-analysed data using a random-effects model. MAIN RESULTS Nineteen trials were included (2164 participants).No study reported data on the number of participants with pain intensity reduction of at least 50% from baseline. Only one study reported data on the number of participants below 30/100 mm on the Visual Analogue Scale (VAS) in pain intensity. Psychological interventions have no beneficial effects in reducing pain intensity measured with continuous scales in the medium-term interval (g -0.02, 95% CI -0.24 to 0.20, 4 studies, 413 participants, moderate quality evidence) nor in the long-term interval (g 0.12, 95% CI -0.09 to 0.33, 3 studies, 280 participants, low quality evidence).No study reported data on median time to remedication or on number of participants remedicated. Only one study provided data on postoperative analgesic use. Studies reporting data on mental distress in the medium-term interval revealed a small beneficial effect of psychological interventions (g 0.36, 95% CI 0.10 to 0.62, 12 studies, 1144 participants, low quality evidence). Likewise, a small beneficial effect of psychological interventions on mental distress was obtained in the long-term interval (g 0.28, 95% CI 0.05 to 0.51, 11 studies, 1320 participants, low quality evidence). There were no beneficial effects of psychological interventions on mobility in the medium-term interval (g 0.23, 95% CI -0.22 to 0.67, 3 studies, 444 participants, low quality evidence) nor in the long-term interval (g 0.29, 95% CI -0.14 to 0.71, 4 studies, 423 participants, low quality evidence). Only one study reported data on time to extubation. AUTHORS' CONCLUSIONS For the majority of outcomes (two-thirds) we could not perform a meta-analysis since outcomes were not measured, or data were provided by one trial only. Psychological interventions have no beneficial effects on reducing postoperative pain intensity or enhancing mobility. There is low quality evidence that psychological interventions reduce postoperative mental distress. Due to limitations in methodological quality, a small number of studies, and large heterogeneity, we rated the quality of the body of evidence as low. Future trials should measure crucial outcomes (e.g. number of participants with pain intensity reduction of at least 50% from baseline) and should focus to enhance the quality of the body of evidence in general. Altogether, the current evidence does not clearly support the use of psychological interventions to reduce pain in participants undergoing open heart surgery.

Outbreak investigation identifies a single Listeria monocytogenes strain in sheep with different clinical manifestations, soil and water.

Listeria (L.) monocytogenes causes orally acquired infections and is of major importance in ruminants. Little is known about L. monocytogenes transmission between farm environment and ruminants. In order to determine potential sources of infection, we investigated the distribution of L. monocytogenes genetic subtypes in a sheep farm during a listeriosis outbreak by applying four subtyping methods (MALDI-TOF-MS, MLST, MLVA and PFGE). L. monocytogenes was isolated from a lamb with septicemia and from the brainstem of three sheep with encephalitis. Samples from the farm environment were screened for the presence of L. monocytogenes during the listeriosis outbreak, four weeks and eight months after. L. monocytogenes was found only in soil and water tank swabs during the outbreak. Four weeks later, following thorough cleaning of the barn, as well as eight months later, L. monocytogenes was absent in environmental samples. All environmental and clinical L. monocytogenes isolates were found to be the same strain. Our results show that the outbreak involving two different clinical syndromes was caused by a single L. monocytogenes strain and that soil and water tanks were potential infection sources during this outbreak. However, silage cannot be completely ruled out as the bales fed prior to the outbreak were not available for analysis. Faeces samples were negative, suggesting that sheep did not act as amplification hosts contributing to environmental contamination. In conclusion, farm management appears to be a crucial factor for the limitation of a listeriosis outbreak.

Assessing the impact of multiple stressors on aquatic biota: the receptor's side matters.

Aquatic ecosystems are confronted with multiple stress factors. Current approaches to assess the risk of anthropogenic stressors to aquatic ecosystems are developed for single stressors and determine stressor effects primarily as a function of stressor properties. The cumulative impact of several stressors, however, may differ markedly from the impact of the single stressors and can result in nonlinear effects and ecological surprises. To meet the challenge of diagnosing and predicting multiple stressor impacts, assessment strategies should focus on properties of the biological receptors rather than on stressor properties. This change of paradigm is required because (i) multiple stressors affect multiple biological targets at multiple organizational levels, (ii) biological receptors differ in their sensitivities, vulnerabilities, and response dynamics to the individual stressors, and (iii) biological receptors function as networks, so that actions of stressors at disparate sites within the network can lead via indirect or cascading effects, to unexpected outcomes.

Intra- and interlaboratory reliability of a cryopreserved trout hepatocyte assay for the prediction of chemical bioaccumulation potential

Measured rates of intrinsic clearance determined using cryopreserved trout hepatocytes can be extrapolated to the whole animal as a means of improving modeled bioaccumulation predictions for fish. To date, however, the intra- and interlaboratory reliability of this procedure has not been determined. In the present study, three laboratories determined in vitro intrinsic clearance of six reference compounds (benzo[a]pyrene, 4-nonylphenol, di-tert-butyl phenol, fenthion, methoxychlor and o-terphenyl) by conducting substrate depletion experiments with cryopreserved trout hepatocytes from a single source. O-terphenyl was excluded from the final analysis due to nonfirst-order depletion kinetics and significant loss from denatured controls. For the other five compounds, intralaboratory variability (% CV) in measured in vitro intrinsic clearance values ranged from 4.1 to 30%, while interlaboratory variability ranged from 27 to 61%. Predicted bioconcentration factors based on in vitro clearance values exhibited a reduced level of interlaboratory variability (5.3-38% CV). The results of this study demonstrate that cryopreserved trout hepatocytes can be used to reliably obtain in vitro intrinsic clearance of xenobiotics, which provides support for the application of this in vitro method in a weight-of-evidence approach to chemical bioaccumulation assessment.

Can the green economy enhance sustainable mountain development? The potential role of awareness building

Mountain socio-ecological systems produce valuable but complex ecosystem services resulting from biomes stratified by altitude and gravity. These systems are often managed and shaped by smallholders whose marginalization is exacerbated by uncertainties and a lack of policy attention. Human–environment interfaces in mountains hence require holistic policies. We analyse the potential of the Global Mountain Green Economy Agenda (GMGEA) in building awareness and thus prompting cross-sectoral policy strategies for sustainable mountain development. Considering the critique of the green economy presented at the Rio + 20 conference, we argue that the GMGEA can nevertheless structure knowledge and inform regional institutions about the complexity of mountain socio-ecological systems, a necessary pre-condition to prompt inter-agency collaboration and cross-sectoral policy formulation. After reviewing the content of the GMGEA, we draw on two empirical cases in the Pakistani and Nepali Himalayas. First, we show that lack of awareness has led to a sequence of fragmented interventions with unanticipated, and unwanted, consequences for communities. Second, using a green economy lens, we show how fragmentation could have been avoided and cross-sectoral policies yielded more beneficial results. Project fragmentation reflects disconnected or layered policies by government agencies, which inherently keep specialized agendas and have no incentive to collaborate. Awareness makes agencies more likely to collaborate and adopt cross-sectoral approaches, allowing them to target more beneficiaries, be more visible, and raise more funds. Nevertheless, we also identify four factors that may currently still limit the effect of the GMGEA: high costs of inter-agency collaboration, lack of legitimacy of the green economy, insufficiently-secured smallholder participation, and limited understanding of the mechanisms through which global agendas influence local policy.

Morphological alterations in the liver of yellow perch (Perca flavescens) from a biological mercury hotspot

Mercury (Hg) contamination is a global issue due to its anthropogenic release, long-range transport, and deposition in remote areas. In Kejimkujik National Park and National Historic Site, Nova Scotia, Canada, high concentrations of total mercury (THg) were found in tissues of yellow perch (Perca flavescens). The aim of this study was to evaluate a possible relationship between THg concentrations and the morphology of perch liver as a main site of metal storage and toxicity. Yellow perch were sampled from five lakes known to contain fish representing a wide range in Hg concentrations in fall 2013. The ultrastructure of hepatocytes and the distribution of Hg within the liver parenchyma were analyzed by transmission electron microscopy (TEM) and electron energy loss spectrometry (EELS). The relative area of macrophage aggregates (MAs) in the liver was determined using image analysis software and fluorescence microscopy. No relation between general health indicators (Fulton's condition index) and THg was observed. In line with this, TEM examination of the liver ultrastructure revealed no prominent pathologies related to THg accumulation. However, a morphological parameter that appeared to increase with muscle THg was the relative area of MAs in the liver. The hepatic lysosomes appeared to be enlarged in samples with the highest THg concentrations. Interestingly, EELS analysis revealed that the MAs and hepatic lysosomes contained Hg.

Source apportionment of elemental carbon in Beijing, China: insights from radiocarbon and organic marker measurements

Elemental carbon (EC) or black carbon (BC) in the atmosphere has a strong influence on both climate and human health. In this study, radiocarbon (14C) based source apportionment is used to distinguish between fossil fuel and biomass burning sources of EC isolated from aerosol filter samples collected in Beijing from June 2010 to May 2011. The 14C results demonstrate that EC is consistently dominated by fossil-fuel combustion throughout the whole year with a mean contribution of 79% ± 6% (ranging from 70% to 91%), though EC has a higher mean and peak concentrations in the cold season. The seasonal molecular pattern of hopanes (i.e., a class of organic markers mainly emitted during the combustion of different fossil fuels) indicates that traffic-related emissions are the most important fossil source in the warm period and coal combustion emissions are significantly increased in the cold season. By combining 14C based source apportionment results and picene (i.e., an organic marker for coal emissions) concentrations, relative contributions from coal (mainly from residential bituminous coal) and vehicle to EC in the cold period were estimated as 25 ± 4% and 50 ± 7%, respectively, whereas the coal combustion contribution was negligible or very small in the warm period.