Flexible foraging strategies of gentoo penguins <Emphasis Type="Italic">Pygoscelis papua</Emphasis> over 5 years in the South Shetland Islands,Antarctica

Gentoo penguins Pygoscelis papua show considerable plasticity in their diet, diving, and foraging behaviors among colonies; we expected that they might exhibit similar variability over time, at a single site, since flexible foraging habits would provide a buffer against changes in prey availability. We examined interannual changes in the foraging strategies and diet of gentoo penguins in the South Shetland Islands, Antarctica, over 5 years with variable prey abundance. Antarctic krill Euphausia superba was the primary diet item, and fish the secondary, though the importance of these items varied among years. Diving behavior also varied over time: different dive depth distributions were observed among years. Nonetheless, chick-rearing success remained relatively constant, indicating that gentoo penguins were able to maintain chick provisioning by altering their foraging strategy among years. Variable abundance of krill in the region did not have observable impacts on the diet, foraging behaviors or chick-rearing success of gentoo penguins. We suggest that foraging plasticity may be one reason that gentoo penguin populations have remained stable in the region, while their congeners (P. antarctica and P. adeliae) with less flexible foraging strategies have declined.     

Variation along the shy–bold continuum in extremophile fishes (<Emphasis Type="BoldItalic">Poecilia mexicana</Emphasis>, <Emphasis Type="BoldItalic">Poecilia sulphuraria</Emphasis>)

One potential trade-off that bold individuals face is between increased predation risks and gains in resources. Individuals experiencing high predation and hungry individuals (or individuals with low body condition) are predicted to show increased boldness. We examined one behavioral trait previously reported to be associated with boldness (the time individual fish needed to emerge from shelter) in various populations of mollies (Poecilia spp.). Our study system included several southern Mexican surface streams with high piscine predation and high food availability, sulfidic surface streams with high avian predation, in which the inhabiting fish show reduced body condition, and a sulfidic cave, where predation and body condition are low. Our comparison revealed very short times to emerge from the start box in populations from non-sulfidic streams. In sulfidic habitats (whether surface or cave), it took individual Poecilia mexicana considerably longer to emerge from the start box, and the same difference was also found in an independent comparison between P. mexicana and the closely related, highly sulfide-adapted Poecilia sulphuraria. Fish reared under common garden conditions (in the absence of predators and hydrogen sulfide) showed intermediate boldness scores to the extremes observed in the field. Our data thus indicate that (a) boldness is shaped by environmental conditions/experiential effects, but is not heritable, (b) predation affects boldness in the predicted direction, but (c) low body condition leads to reduced boldness. Extremophile Poecilia spp. spend most of their time surfacing to survive under sulfidic and hypoxic conditions, which exposes them to increased levels of predations, but the fish forage on the bottom. Hence, in this system, increased boldness does not increase foraging success. We argue that energy limitation favors reducing energetically costly behaviors, and exploring novel environments may be just one of them.     

Effects of Ergorest® Arm Supports on Muscle Strain and Wrist Positions During the Use of the Mouse and Keyboard in Work With Visual Display Units: A Work Site Intervention

The effects of Ergorest^® arm supports on wrist angles and musculoskeletal strain in the neck-shoulder-arm region and electrical activity in the shoulder and arm muscles were studied during typing or the use of the mouse in work with a visual display unit (VDU). Twenty-one women were randomized into 3 groups (1 arm support, 2 arm supports, and control). Measurements were carried out before and after the 6-week intervention. The wrist extension of the mouse hand, the muscle activity of the trapezius muscle, and the subjective discomfort ratings indicated that 2 arm supports were better than 1 in work with a mouse. The Ergorest^® arm support alleviates muscle and joint strain in VDU work when used for both arms.     

An economic assessment of drought effects on three grassland systems in Switzerland

This paper analyzes the economic impacts of summer drought on Swiss grassland production. We combine field trial data from drought experiments in three different grasslands in Switzerland with site-specific information on economic costs and benefits. The analysis focuses on the economic implications of drought effects on grassland yields as well as grassland composition. In agreement with earlier studies, we found rather heterogeneous yield effects of drought on Swiss grassland systems, with significantly reduced yields as a response to drought at the lowland and sub-alpine sites, but increased yields at the wetter pre-alpine site. Relative yield losses were highest at the sub-alpine site (with annual yield losses of up to 37 %). However, because income from grassland production at extensive sites relies to a large extent on ecological direct payments, even large yield losses had only limited implications in terms of relative profit reductions. In contrast, negative drought impacts at the most productive, intensively managed lowland site were dominant, with average annual drought-induced profit margin reductions of about 28 %. This is furthermore emphasized if analyzing the farm level perspective of drought impacts. Combining site-specific effects at the farm level, we found that in particular farms with high shares of lowland grassland sites suffer from summer droughts in terms of farm-level fodder production and profit margins. Moreover, our results showed that the higher competitiveness of weeds (broad-leaved dock) under drought conditions will require increasing attention on weed control measures in future grassland production systems. Taking into account that the risk of drought occurrence is expected to increase in the coming years, additional instruments to cope with drought risks in fodder production and finally farmers’ income have to be developed.     

Association between resiliency and posttraumatic growth in firefighters: the role of stress appraisal

The purpose of this study was to establish the relation between resiliency and the level of positive changes, comprising posttraumatic growth in a group of firefighters experiencing job-related traumatic events and the mediating role of stress appraisal in this relation. The study was performed on a group of 100 firefighters from firefighting and rescue brigades, out of which 75 admitted to experiencing a traumatic event. Firefighters covered by the study were on average 31.51 years old (SD?=?6.34). A Polish version of Posttraumatic Growth Inventory, the Resiliency Assessment Scale and Stress Appraisal Questionnaire were used in the study. The results have shown that 22.7% of firefighters displayed low, 58.6% average and 18.7% high intensity of positive changes resulting from a traumatic event. Resiliency poorly correlates with posttraumatic growth expressed in changes in self-perception, and strongly correlates with stress appraisal, negatively correlates with threat and harm/loss and positively correlates with challenge. Appraisal of stress as a threat and challenge appeared to be mediators of the relationship between resiliency and posttraumatic growth.     

The efficacy of maternal age screening for Down's syndrome in Wessex

The uptake of amniocentesis in Wessex for the period 1986–1988 was 36 per cent (2873 of 8004 births), a proportion that has not altered significantly since 1984. There is a large difference in uptake between women in the lower risk age group, 35–36 years, and those in the higher risk group, 37 + years, and very considerable differences in uptake among different districts. The prenatal detection over the 3-year study period for women aged 35 or more, after correction for spontaneous loss of Down's syndrome fetuses between prenatal detection and birth, is 53 per cent, a figure that must be inflated due to our failure to ascertain all liveborn Down's syndrome patients.     

有机负荷对酒糟厌氧消化降解及甲烷产率的影响

为了探究有机负荷对酒糟中温厌氧消化运行的稳定性及产气性能的影响,启动了有机负荷分别为1.6、4.8和6.4 kg·（m3·d）-1的厌氧反应器R1、R2和R3,并以半连续方式运行100 d。单因素方差分析（ANOVA）的结果表明,3个反应器在60~90 d的VS降解率无显著性差异（p=0.19>0.05）,分别为（66.9±3.2）%、（68.1±2.7）%和（66.1±1.5）%,但产气率随着有机负荷的提高而升高,分别为（0.48±0.07）、（0.61±0.06）、（0.71±0.06）m3·kg-1,对应的甲烷比例为56.9%、60.9%和59.6%。虽然提高有机负荷促进了有机碳源利用效率,提高了甲烷比例和产量,但其稳定运行存在一定困难,R3在90 d后产气急剧下降,丙酸大量积累,产酸菌和产甲烷菌间的动态平衡受到破坏。因而,适宜的有机负荷是确保酒糟良好的厌氧消化稳定性能和产气性能的关键因素。     

Organochlorine contaminants in seven species of Arctic seabirds from northern Baffin Bay

Organochlorine contaminants (OCs) were determined in liver and fat of seven species of seabirds (Alle alle, Uria lomvia, Cepphus grylle, Rissa tridactyla, Pagophila eburnea, Larus hyperboreus, and Fulmaris glacialis) collected in May/June 1998 from the Northwater Polynya in northern Baffin Bay. OC concentrations ranged over an order of magnitude between seabird species and OC groups, with PCBs having the highest concentrations followed by DDT, chlordane, HCH and ClBz. Positive relationships between delta15N (estimator of trophic level) and OC concentrations (lipid basis) were found for all OC groups, showing that trophic position and biomagnification significantly influence OC concentrations in Arctic seabirds. Concentrations of a number of OCs in particular species (e.g., HCH in P. eburnean) were lower than expected based on delta15N and was attributed to biotransformation. P. eburnea and F. glacialis, which scavenge, and R. tridactyla, which migrate from the south, were consistently above the delta15N-OC regression providing evidence that these variables can elevate OC concentrations. Stable isotope measurements in muscle may not be suitable for identifying past scavenging events by seabirds. OC relative proportions were related to trophic position and phylogeny, showing that OC biotransformation varies between seabird groups. Trophic level, migration, scavenging and biotransformation all play important roles in the OCs found in Arctic seabirds.     

Use and fate of pesticides in the Amazon State,Brazil

During the last 30 years, the increase of the human population in the Amazon introduced the need for additional food production and caused the state government to implement programs to increase and improve agricultural production. The production of nontraditional crops introduced several problems unknown to traditional farmers, since they are not well adapted to tropical conditions. Their susceptibility to insects, fungi and other plagues, and the competition with native vegetation forced farmers to use pesticides intensively. Amazonian farmers were not adequately prepared for the use of this new technology; they ignored the risk of pesticides to human health and the environment. Using the region of the state capital Manaus as an example, the characteristics of the pesticide use are described (e.g. the increased use and the lack of personal protective equipment, as well as the legal situation). In detail, the registration status of pesticides used in the State of Amazonas and the state of their registration in the European Union is compared. Finally, it is concluded that the use and the fate of pesticides in the Amazon region has to be monitored. Data of the effects on humans and on the environment have to be collected from the literature or have to be produced in standardized tests, so that an environmental risk assessment becomes possible. Training and information programs are urgently needed in order to build up environmentally sustainable agriculture. Finally, the enforcement of Brazilian laws concerning pesticide registration has to be improved.     

Influence of combustion temperature on the performance of sewage sludge ash as a supplementary cementitious material

The potential for using sewage sludge ash (SSA) as a supplementary cementitious material (SCM) has been investigated. Controlled combustion of sewage sludge collected in Croatia from two wastewater treatment plants produced SSA with different characteristics. These were used to substitute for cement in mortar samples. The chemical composition and physical properties of SSA depend on wastewater composition, the sludge treatment process and the combustion temperature. These factors influence the suitability of SSA to be used as a SCM. For three different combustion temperatures (800, 900 and 1000 °C), it was concluded that properties of fresh mortar were not affected while in the hardened state, the most favorable combustion temperature is 900 °C regarding mechanical properties. Regardless of combustion temperature, for all types of SSA used in mortars as cement replacement (up to 30%), the average decrease in both compressive and flexural strength values was less than 8% for every 10% of added SSA. The results presented indicate that using up to 20% replacement of cement by SSA produces mortars that meet the specific technical requirements analyzed in this work.