Levels Of Environmental Stress Research Articles

Exercise, immune function and respiratory infection: An update on the influence of training and environmental stress

This review outlines recent advancements in the understanding of athlete immune health. Controversies discussed include whether high levels of athletic training and environmental stress (for example, heat acclimation, cryotherapy and hypoxic training) compromise immunity and increase upper respiratory tract infection (URTI). Recent findings challenge early exercise immunology doctrine by showing that international athletes performing high-volume training suffer fewer, not greater, URTI episodes than lower-level performers and URTI incidence decreases, not increases, around the time of competition compared with heavy training. Herein we raise the possibility of host genetic influences on URTI and modifiable behavioural and training-related factors underpinning these recent observations. Continued controversy concerns the proportion of URTI symptoms reported by athletes that are due to infectious pathogens, airway inflammation or as yet unknown causes and indeed whether the proportion differs in athletes and non-athletes. Irrespective of the cause of URTI symptoms (infectious or non-infectious), experts broadly agree that self-reported URTI hinders high-volume athletic training but, somewhat surprisingly, less is known about the influence on athletic performance. In athletes under heavy training, both innate and acquired immunity are often observed to decrease, typically 15-25%, but whether relatively modest changes in immunity increase URTI susceptibility remains a major gap in knowledge. With the exception of cell-mediated immunity that tends to be decreased, exercising in environmental extremes does not provide an additional threat to immunity and host defence. Recent evidence suggests that immune health may actually be enhanced by regular intermittent exposures to environmental stress (for example, intermittent hypoxia training).

Role of Acclimatization in Weather-Related Human Mortality During the Transition Seasons of Autumn and Spring in a Thermally Extreme Mid-Latitude Continental Climate.

Human mortality is closely related to natural climate-determined levels of thermal environmental stress and the resulting thermophysiological strain. Most climate-mortality research has focused on seasonal extremes during winter and summer when mortality is the highest, while relatively little attention has been paid to mortality during the transitional seasons of autumn and spring. The body acclimatizes to heat in the summer and cold in winter and readjusts through acclimatization during the transitions between the two during which time the body experiences the thermophysiological strain of readjustment. To better understand the influences of weather on mortality through the acclimatization process, the aim here is to examine the periods that link very cold and very warms seasons. The study uses the Acclimatization Thermal Strain Index (ATSI), which is a comparative measure of short-term thermophysiological impact on the body. ATSI centers on heat exchange with the body’s core via the respiratory system, which cannot be protected. The analysis is based on data for a major city in the climatic region of the Russian Far East characterized by very hot summers and extremely cold winters. The results show that although mortality peaks in winter (January) and is at its lowest in summer (August), there is not a smooth rise through autumn nor a smooth decline through spring. A secondary peak occurs in autumn (October) with a smaller jump in May. This suggests the acclimatization from warm-to-cold produces more thermophysiological strain than the transition from cold-to-warm. The study shows that ATSI is a useful metric for quantifying the extent to which biophysical adaptation plays a role in increased strain on the body during re-acclimatization and for this reason is a more appropriate climatic indictor than air temperature alone. The work gives useful bioclimatic information on risks involved in transitional seasons in regions characterized by climatic extremes. This could be handy in planning and managing health services to the public and measures that might be used to help mitigate impacts.

Creeping Bentgrass Putting Green Response to Combined Mowing, Rolling, and Foot Traffic Under Environmental Stress

Creeping bentgrass (Agrostis stolonifera L.) putting greens in the transition zone experience high levels of environmental stress during summer months. The interaction of common management practices combined with foot traffic can exacerbate environmental stress. The objective of this study was to determine the effect of management practices combined with foot traffic during high environmental stress in the transition zone. Creeping bentgrass cultivars, SR 1020 and Penn G2, were managed with various mowing heights (2.5, 3.2, or 4.0 mm), rolling frequencies (0, 3, or 6 d per week), and foot traffic. As environmental stress became prominent during summer months, bentgrass maintained at the lowest mowing heights exhibited poorer turf quality, coverage, and wear tolerance compared to the highest mowing height. SR 1020 quality was reduced below acceptable levels in July when mowed at the lowest mowing height in 2011 and 2012. Penn G2 maintained acceptable quality at all mowing heights in 2011, but severe heat and drought stress reduced turf quality regardless of mowing height in 2012. Daily rolling significantly increased wear on both cultivars during high environmental stress that resulted in decreased turf quality and coverage compared to the non‐rolled treatments. The combination of wear from mechanical stress and foot traffic increased wear injury on both cultivars. Under reduced daylengths and optimal air temperatures in September of each year, all response variables improved to similar levels.

Multi‐scale environmental filters and niche partitioning govern the distributions of riparian vegetation guilds

Across landscapes, riparian plant communities assemble under varying levels of disturbance, environmental stress, and resource availability, leading to the development of distinct riparian life‐history guilds over evolutionary timescales. Identifying the environmental filters that exert selective pressures on specific riparian vegetation guilds is a critical step in setting baseline expectations for how riparian vegetation may respond to environmental conditions anticipated under future global change scenarios. In this study, we ask: (1) What riparian plant guilds exist across the interior Columbia and upper Missouri River basins? (2) What environmental filters shape riparian guild distributions? (3) How does resource partitioning among guilds influence guild distributions and co‐occurrence? Woody species composition was measured at 703 stream reaches and each species' morphological and functional attributes were extracted from a database in four categories: (1) life form, (2) persistence and growth, (3) reproduction, and (4) resource use. We clustered species into guilds by morphological characteristics and attributes related to environmental tolerances, modeling these guilds' distributions as a function of environmental filters—regional climate, watershed hydrogeomorphic characteristics, and stream channel form—and guild co‐existence. We identified five guilds: (1) a tall, deeply rooted, long‐lived, evergreen tree guild, (2) a xeric, disturbance tolerant shrub guild, (3) a hydrophytic, thicket‐forming shrub guild, (4) a low‐statured, shade‐tolerant, understory shrub guild, and (5) a flood tolerant, mesoriparian shrub guild. Guilds were most strongly discriminated by species' rooting depth, canopy height and potential to resprout and grow following biomass‐removing disturbance (e.g., flooding, fire). Hydro‐climatic variables, including precipitation, watershed area, water table depth, and channel form attributes reflective of hydrologic regime, were predictors of guilds whose life history strategies had affinity or aversion to flooding, drought, and fluvial disturbance. Biotic interactions excluded guilds with divergent life history strategies and/or allowed for the co‐occurrence of guilds that partition resources differently in the same environment. We conclude that the riparian guild framework provides insight into how disturbance and bioclimatic gradients shape riparian functional plant diversity across heterogeneous landscapes. Multiple environmental filters should be considered when the riparian response guild framework is to be used as a decision‐support tool framework across large spatial extents.

Regional industrial growth and environmental impacts in the Bohai Sea rim region of China: uncertainty in location choice

Regional industrial growth is facing the problems of no control and disorder in rapidly transitioning China, especially in mega-regional areas. These problems have significantly intensified the use of regional resources and the level of environmental stress. The integration of industrial development and the environmental pollution pressure simulation at the mega-regional level must be supported at the planning stage. In this study, a Computational System for Regional Industrial Distribution Simulation and Environmental Impact Assessment (RESEA) that combines a multi-nominal logit model and uncertainty analysis was developed. This system aimed to explore efficient industrial spatial distribution simulations and potential environmental pressures at the mega-regional level. This study also developed an uncertainty analysis framework to identify and apply a bottom-up system with aggregate and sparse data following the basic processes of an HSY algorithm and Global-Formed Regional Sensitivity Analysis, which is capable of considering both input uncertainty and parameter uncertainty. By applying the RESEA system, a process of model estimation and sensitivity analysis was implemented based on historic data from 2002 to 2008 for the Bohai Sea rim region in China. The future industry distribution for the year 2015 was later aggregated based on the chosen sizes and locations of newly added industrial plants. Finally, the pollution loads of surface water into every sub-region were calculated, and the potential environmental impacts of different strategies were discussed.

Patterns of reproductive traits of fucoid species in core and marginal populations

Fucoid macroalgae are important primary producers and habitat modifiers on North Atlantic intertidal rocky shores. With decreasing latitude, western European fucoid populations display reduced levels of abundance, biomass and recruitment, while experiencing higher levels of physical environmental stress during summer months. We hypothesized that such reduction in the south is accompanied by a detectable decline in fucoid reproductive capacity. To test this hypothesis, morphological and reproductive traits of core (Welsh) and marginal (Portuguese) populations of two common fucoid species, Fucus vesiculosus and F. spiralis (Ochrophyta, Fucales), were examined. Morphological measurements showed that for a given thallus length, both fucoid species had smaller thallus volume and lower biomass in the southerly marginal part of the range. Significantly lower biomass of reproductive tissue of F. vesiculosus and a smaller number of receptacles per individual on specimens of both species indicate that levels of reproductive output are probably lower in southern populations. Despite the differences in reproductive traits observed between regions, reproductive effort (measured as the percentage of total dry biomass represented by reproductive tissue) of both species remained similar, as algae from both regions made similar investments in reproduction. The results indicate that stressful conditions reduced growth and number of receptacles of both species and amount of reproductive biomass of F. vesiculosus in the south but do not seem to change the way these algal species invest their energy. The decline in mass and reproductive biomass of specimens from southern shores found in this study, when combined with the lower abundance of adults and lower recruitment levels previously observed, is a strong indication of fucoid populations with lower levels of propagule output. This is an important factor when considering responses of these populations to a changing environment.

Identifying Ecological Red Lines: A Case Study of the Coast in Liaoning Province

The global decline in estuarine and coastal ecosystems is affecting critical ecosystem services. The spatial agglomeration of population, industries and resources has led to the emergence of regionally-specific ecological problems. Therefore, identifying “ecological red lines”, based on specific natural and environmental features, could help to differentiate the economic development and ecological protection directions or potentials of different regions in future. The aim of this case study is to define the ecological red line in the coastal zone of Liaoning Province, China, by evaluating the ecological importance and environmental stress in its marine and terrestrial ecosystems. For this purpose, the ecological importance of this area was first classified into four conservation indices (species, wetland, water and coast and islands) and assigned values of 5, 3 and 1 for indications of high, moderate and minor importance. In the meantime, environmental stress was also classified into four indices (water environment, salinization, soil erosion and erosion of coasts and islands) and assigned values of 5, 3 and 1 for indications of high, moderate and low stress, respectively. Then, based on an overlay analysis and evaluation of the above results, we defined two grades of ecological red line zones. Grade I ecological red line zones contain the areas with critical and diverse ecosystem services, areas of high importance for species conservation and nature reserves, as well as ecologically-vulnerable and sensitive areas. It is important in these areas to maintain the biological diversity and to improve the quality of the ecological environment, which should be strictly protected and explicitly controlled. Grade II ecological red line zones display areas with minimum requirements for maintaining the basic needs of a livable environment and human health, moderate to minor levels of ecological importance and high to moderate levels of environmental stress. To better control and protect such ecological red lines, setting up an ecological inventory through remote sensing satellites and ground-level monitoring and appraising the effectiveness of dynamical protection are highly recommended.

The Effect of Soil Moisture on the Reflectance Spectra Correlations in Beech and Sessile Oak Foliage/ Talajnedvesség hatása bükk és kocsánytalan tölgy lombozat reflexiós spektrumainak korrelációira.

Abstract Reflectance intensities of foliage are mostly due to biomaterials synthesised by plants. Adaptation to the continuously changing environment requires the regulated alteration of metabolic processes, which also influences the UV-VIS (Ultraviolet-Visible) and IR (Infra Red) spectra of leaves. For the calculation of various Vegetation Indices (VIs), e.g. NDVI (Normalized Difference Vegetation Index), the common practice is to use the reflectance spectrum of the whole foliage and when individual leaves of the same plant are sampled, an average VI is derived. On the contrary, our method exploits the small differences between individual leaves of the same plant, making use of the similar distributions of measured reflectance values. Using particular wavelength pairs, linear regressions of reflectance intensities have been investigated. The parameters of these regressions (slope and intercept) have been compared to the temporal variations of the environmental factors, such as temperature, vapour pressure deficit and soil moisture. By assessing the sensitivity of the regression coefficient (slope) to the changing environment, wavelength pairs can be selected whose sensitivity change reflects the effect of soil moisture deficit on the plant. Based on the state-dependent correlations of the reflectance spectra of plant foliage, a new concept is presented that is capable of indicating the level of environmental stress, e.g. drought stress.

Fluctuating asymmetry in Menidia beryllina before and after the 2010 Deepwater Horizon oil spill.

Assessing the impacts of the Deepwater Horizon oil spill with a dependable baseline comparison can provide reliable insight into environmental stressors on organisms that were potentially affected by the spill. Fluctuating asymmetry (small, non-random deviations from perfect bilateral symmetry) is an informative metric sensitive to contaminants that can be used to assess environmental stress levels. For this study, the well-studied and common Gulf of Mexico estuarine fish, Menidia beryllina, was used with pre and post-oil spill collections. Comparisons of fluctuating asymmetry in three traits (eye diameter, pectoral fin length, and pelvic fin length) were made pre and post-oil spill across two sites (Old Fort Bayou and the Pascagoula River), as well as between years of collection (2011, 2012)-one and two years, respectfully, after the spill in 2010. We hypothesized that fluctuating asymmetry would be higher in post-Deepwater Horizon samples, and that this will be replicated in both study areas along the Mississippi Gulf coast. We also predicted that fluctuating asymmetry would decrease through time after the oil spill as the oil decomposed and/or was removed. Analyses performed on 1135 fish (220 pre and 915 post Deepwater Horizon) showed significantly higher post spill fluctuating asymmetry in the eye but no difference for the pectoral or pelvic fins. There was also higher fluctuating asymmetry in one of the two sites both pre and post-spill, indicating observed asymmetry may be the product of multiple stressors. Fluctuating asymmetry decreased in 2012 compared to 2011. Fluctuating asymmetry is a sensitive measure of sub lethal stress, and the observed variability in this study (pre vs. post-spill or between sites) could be due to a combination of oil, dispersants, or other unknown stressors.

辽河流域大型底栖动物耐污值研究

PDF HTML阅读 XML下载 导出引用 引用提醒 辽河流域大型底栖动物耐污值 DOI: 10.5846/stxb201311082699 作者: 作者单位: 中国环境科学研究院 环境基准与风险评估国家重点实验室;中国环境科学研究院 流域水生态研究室,中国环境科学研究院 环境基准与风险评估国家重点实验室;中国环境科学研究院 流域水生态研究室,中国环境科学研究院 环境基准与风险评估国家重点实验室;中国环境科学研究院 流域水生态研究室,中国环境科学研究院 环境基准与风险评估国家重点实验室;中国环境科学研究院 流域水生态研究室,中国水利水电科学研究院 水环境研究所,中国环境科学研究院 环境基准与风险评估国家重点实验室;中国环境科学研究院 流域水生态研究室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家水体污染控制与治理科技重大专项(2012ZX07501-001-04); 中欧环境可持续发展计划(DCI-ASIE/2013/323-261); 国家自然科学基金(2010KYYW06); 国家自然科学基金(41401066) Tolerance values of macroinvertebrate taxa in Liao River basin Author: Affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences;Laboratory of Riverine Ecological Conservation and Technology,Chinese Research Academy of Environmental Sciences,State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences;Laboratory of Riverine Ecological Conservation and Technology,Chinese Research Academy of Environmental Sciences,State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences;Laboratory of Riverine Ecological Conservation and Technology,Chinese Research Academy of Environmental Sciences,State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences;Laboratory of Riverine Ecological Conservation and Technology,Chinese Research Academy of Environmental Sciences,Department of Water Environment,China Institute of Water Resources and Hydropower Research,State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences;Laboratory of Riverine Ecological Conservation and Technology,Chinese Research Academy of Environmental Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:大型底栖动物耐污值是构建河流生物评价指标的基础。受自然地理区域影响,同一分类单元的耐污值会出现地域上的差异,因此计算和修订适用于某一研究区域的耐污值是准确评价该区域河流健康状况的前提。目前尚未有针对我国北方河流大型底栖动物耐污值计算和修订的报道,基于2009年春季、秋季和2010年夏季在辽河流域308个样点的大型底栖动物数据,采用Simpson多样性指数的水质分级标准对所有样点的水质等级进行了划分,并利用累积分位数法计算获得了辽河流域大型底栖动物195个分类单元的耐污值;同时参考专家经验和相关文献核定了其余71个分类单元的耐污值。依据耐污值敏感特征划分标准,辽河流域大型底栖动物优势类群以敏感种和一般耐污种为主,两者几乎占到总分类单元数的84%,耐污类群种类较少,仅占16%。其中敏感类群有齿蛉科Corydalidae,襀科Perlidae,原石蛾科Rhyacophilidae,细裳蜉科Leptophlebiidae等;一般耐污类群有纹石蛾科Hydropsychidae,四节蜉科Baetidae,扁蜷螺科Planorbidae等;耐污类群有颤蚓科Tubificidae、石蛭科Erpobdellidae等。 Abstract:Tolerance represents the relative capacity of aquatic organisms to survive and reproduce under different levels of environmental stress. Tolerance values (TVs) of macroinvertebrates are broadly used for calculating metrics applied in bioassessment. Variability among TVs may be related to regional differences in macroinvertebrate sensitivity to pollution; whether the calculations and amendments of TVs are appropriate for one region is the basis for accurate evaluation of river health condition. Two methods, namely, expert opinion and statistical analysis, have been used to derive the TVs of macroinvertebrate taxa. The TVs currently used in bioassessment of northern rivers in China were acquired from relevant literature and expert opinion. The bioassessment results, however, will be more accurate if the TVs are derived from statistical analysis. The objective of the current study was to derive the TVs appropriate for macroinvertebrate taxa in northeastern rivers in China. Macroinvertebrate data from 308 samples were collected in spring and autumn in 2009 and summer in 2010 in the Liao River basin. Using the revised Simpson index, we assigned the water quality into five categories as: ≥ 10, excellent; ≥ 6, good; ≥ 3, good-fair; ≥ 2, fair; and < 2, poor. Different scores were marked to different water quality: excellent, 1; good, 2; good-fair, 3; fair, 4 and poor, 5. Macroinvertebrates were grouped and coded based on abundance at each site: < 1 ind./sample = 0; 1-2 ind./sample = 1; 3-9 ind./sample = 3; and ≥ 10 ind./sample = 10. The average abundance values for each taxon were calculated for each of the five water quality classes. The average abundance values were converted into a cumulative percentile: the 75th percentile value was used for a taxon that had > 10 records and the 50th percentile value was used for a taxon that had 5-10 records. This yielded preliminary tolerance values of 0.0-4.5, which were transformed to final tolerance values on a 0-10 scale. A total of 195 macroinvertebrate taxa TVs were calculated, including one genus in one family for each Megaloptera, Amphipoda, Decapoda, Basommatophora, Unionoida, Tubificida, Hirudinea, Turbellaria, and Arachnida; one family of Collembola; two families (including one taxon at genus-level) of Hemiptera; five genera in three families of Plecoptera; five genera in four families of Odonata; five genera in four families of Mesogastropoda; six families (including five taxa at genus-level) of Coleoptera; 13 genera in 10 families of Trichoptera; 17 genera in eight families of Ephemeroptera; and 18 genera and three sub-families in 12 families of Diptera. The other 71 TVs were derived from expert opinion and relevant literature. TVs were classified according to sensitivity as: TV ≤ 3, intolerant; 3 < TV < 7, intermediate; and TV ≥ 7, tolerant. The dominant macroinvertebrate families in the Liao River basin were divided into the three groups as follows: intolerant group, including Corydalidae (2.1), Perlidae (1.3-2.1), Rhyacophilidae (0.6-3.0), and Leptophlebiidae (0.4-1.7); intermediate group, including Hydropsychidae (3.7-5.3), Baetidae (3.4-6.2), and Planorbidae (3.7-5.5); and tolerant group, including Tubificidae (5.0-9.9) and Erpobdellidae (7.8-8.6). The intolerant and intermediate groups comprised nearly 84% of the total taxa, while the tolerant group comprised only 16% of the total taxa. We suggest that TVs can be used to assess the water quality of streams and rivers in northern China. 参考文献 相似文献 引证文献

Fine‐scale heterogeneity across Manhattan's urban habitat mosaic is associated with variation in ant composition and richness

Abstract Global urbanisation is rapidly expanding and most of the world's humans now live in cities. Most ecological studies have, however, focused on protected areas. To address this issue, we tested predictions from studies of protected areas in urban ecosystems. Because most cities are heterogeneous habitat mosaics which include habitats with varying levels of chronic environmental stress, we focused on predictions from studies of less modified ecosystems about community‐wide responses to variation in chronic stress. We sampled ants across Manhattan's urban habitat mosaic, at sites with varying levels of chronic environmental stress. Many predictions derived from less modified ecosystems were supported by our findings: despite being the most intensively sampled habitat, high stress urban medians had less variability in ant composition –both within and among sites – than either urban parks or urban forests, the lowest stress habitat – urban forests‐had significantly more accumulated species and a higher number of unique species than higher stress habitats, and urban parks, which have intermediate levels of chronic environmental stress, also had intermediate levels of variation in among‐site species composition, accumulated species richness, and the incidence of unique species. The most common species also differed across Manhattan's urban habitat mosaic. Nevertheless, the prediction that exotic species would occur more frequently in higher stress habitats was not supported; exotic species were equally common across all habitats. These findings suggest that fine‐scale heterogeneity in the chronic stress of urban habitats may be an underappreciated, but important structuring force for urban animal communities.

Taxonomic overview and tusk growth analyses of Ziegler Reservoir proboscideans

At an altitude of 2705m in the Colorado Rockies (USA), the Ziegler Reservoir fossil site gives a rare look at a high-elevation ecosystem from the late Pleistocene (especially MIS 5) of North America. Remains of more than four mammoths and about 35 mastodons dominate the macrofossil assemblage. Mammoth remains are attributed to Mammuthus columbi, and mastodon remains are referred to the well-known, continent-wide Mammut americanum. Mastodon remains occur within and between several lake-margin slump deposits. Their deposition must therefore have occurred as events that were to some degree separate in time. We treat the mastodon assemblage in each stratigraphic unit as a source of information on environmental conditions during the lives of these individuals. Mastodon mandibular tusks are abundant at the site and represent both males and females, from calves to full-grown adults. This study presents the first attempt to use microCT, thin-section, and isotope records from mandibular tusks to reconstruct features of life-history. We recognize an up-section trend in δ18O profiles toward higher values, suggestive of warmer temperatures. Throughout this sequence, mastodon growth histories show low mean sensitivities suggestive of low levels of environmental stress. This work helps frame expectations for assessing environmental pressures on terminal Pleistocene populations.

Memory and fitness optimization of bacteria under fluctuating environments.

Bacteria prudently regulate their metabolic phenotypes by sensing the availability of specific nutrients, expressing the required genes for their metabolism, and repressing them after specific metabolites are depleted. It is unclear, however, how genetic networks maintain and transmit phenotypic states between generations under rapidly fluctuating environments. By subjecting bacteria to fluctuating carbon sources (glucose and lactose) using microfluidics, we discover two types of non-genetic memory in Escherichia coli and analyze their benefits. First, phenotypic memory conferred by transmission of stable intracellular lac proteins dramatically reduces lag phases under cyclical fluctuations with intermediate timescales (1–10 generations). Second, response memory, a hysteretic behavior in which gene expression persists after removal of its external inducer, enhances adaptation when environments fluctuate over short timescales (<1 generation). Using a mathematical model we analyze the benefits of memory across environmental fluctuation timescales. We show that memory mechanisms provide an important class of survival strategies in biology that improve long-term fitness under fluctuating environments. These results can be used to understand how organisms adapt to fluctuating levels of nutrients, antibiotics, and other environmental stresses.

Bilateral Asymmetry of Long Bones in Bronze and Early Iron Age Pastoralists of the Altai

The aim of the study is to explore patterns of directional asymmetry (DA) of long bones among the ancient pastoralists of the Russian Altai. Long bones of the upper and lower limbs and clavicles were measured bilaterally in two temporally diverse skeletal samples dating to the Middle Bronze Age and the Early Iron Age. Statistically significant sex and chronological differences were found in DA of the upper limb diaphyseal breadths, which are strongly influenced by mechanical factors during life. These results suggest that manual loadings were bilaterally symmetric in males, but not in females. Sexual dimorphism in the upper-limb-use asymmetry was greater in the later group than in the earlier group. Besides, the female subgroups exhibited strong DA in features evidencing biomechanical stress on the femur. Temporal differences in DA of the upper limb length are possibly due to changes in the level of environmental and/or genetic stress. * Supported by the Russian Foundation for Basic Research (Project No. 11-06-00360а) and the Russian Foundation for the Humanities (Project No. 12-01-00159).

SEAWEEDS AS ECOSYSTEM ENGINEERS

Canopy-forming seaweeds are often considered as important foundation species or ecosystem engineers. In wave-sheltered rocky intertidal habitats in Atlantic Canada, macroalgal canopies are composed primarily of Ascophyllum nodosum and secondarily of Fucus spp. Field experiments revealed that the effects of these canopies on benthic communities (considering primary producers and consumers) depend on the level of environmental stress that is determined by tides. Positive canopy effects occur at high and middle elevations, where canopies ameliorate the otherwise harsh conditions during low tides, but no significant effects occur at low elevations, where conditions remain mild during low tides regardless of canopy presence. Canopies of fucoid algae covering the intertidal zone during a low tide on a wave-sheltered rocky shore in Nova Scotia, Canada. Photograph by R. A. Scrosati. This photograph illustrates the data paper “Experimental and mensurative data on the abundance of primary producers and consumers from intertidal habitats in Canada” by Cortney A. Watt and Ricardo A. Scrosati, which appeared in Ecology 95(5):1429. http://dx.doi.org/10.1890/14-0071.1

Aging life prediction system of polymer outdoors constructed by ANN. 1. Lifetime prediction for polycarbonate

By the application of artificial neural network (ANN), the concept of constructing polymers' aging life prediction system has been proposed for the first time in the present work. Such a system can be designed via integrating several independent ANN modules playing different roles: the S module for calculating environmental stress level, the F module for outputting the feature of aging life distribution, the Sa module for computing the accelerated environmental stress level, the aT module for studying the correspondence between life distribution of certain accelerated and natural aging tests, and the structure module for converting polymer structures into structure parameter matrix. Here polycarbonate, as a widely used engineering thermoplastic with complex aging behavior and various aging mechanisms, has been researched to constructing its aging life model with the help of the systematic ANN method above, which well reflects huge potential of ANN's application in the field of polymers' aging life prediction for practical application.

The evolution of self-organizing communication networks in high-risk social-ecological systems

Recently published research shows that members of regional communication networks form links based on how risky their exchanges with others may be: low-risk situations favor the creation of bridging structures that solve coordination problems, whereas high-risk situations lead to the establishment of bonding structures that make detection and punishment of defection more likely. This basic expectation has been tested in low-risk regional arenas, where indeed more bridging structures formed in time (Berardo and Scholz 2010). However, no empirical evidence on the formation of networks has been produced yet in high-risk social-ecological systems (HRSES). In this article, I study the network of communication among stakeholders in a small river basin in Argentina that has been subject to high levels of environmental stress over the last decades and empirically test whether more bonding structures tend to form in this high-risk SE system. Findings show that actors in the network have a tendency to create more triadic bonding structures, as expected. However, complementary results offer a more nuanced picture of how networks look like in highly-risky regional settings and caution against an overly optimistic view linking bonding in networks to the solution of collective action problems of a regional scale.

Comparison of serum biochemistry and haematology values in captive and free-ranging wild boar (Sus scrofa)

The purpose of this study was to compare haematology and biochemistry data for captive and free-ranging wild boar in the UK and to evaluate whether significant differences were present between these two boar populations. The samples from the captive wild boar comprised 18 adult females housed in three interconnected outdoor paddocks, whilst the samples from free-ranging wild boar comprised 19 adult females living in unrestricted woodland. Samples were obtained under general anaesthesia during health checks. Free-ranging wild boar had significantly lower serum concentrations of total protein, globulin, ionised calcium, urea, creatinine and gamma-glutamyl transferase (GGT) activity and significantly higher serum concentrations of phosphate, bile acids and alkaline phosphatase (ALP) activity compared with captive wild boar. Haematological values for free-ranging wild boar showed significantly higher red blood cell counts (RBC), white blood cell counts (WBC) and neutrophil counts and significantly lower mean cell volume (MCV) and mean corpuscular haemoglobin (MCH). These results provide evidence that significant differences in serum biochemistry and haematology values may exist between captive and free-ranging populations of the same native species. Such differences may need to be considered when studies are undertaken or reported from wild animal populations in semi-natural husbandry situations. Potential sources of these differences may include nutritional state, level of activity and environmental stress.

Frequency of micronuclei and of other nuclear abnormalities in erythrocytes of the grey mullet from the Mondego, Douro and Ave estuaries—Portugal

Fish are bioindicators of water pollution, and an increased rate of their erythrocyte nuclear morphological abnormalities (ENMAs)-and particularly of erythrocyte micronuclei (EMN)-is used as a genotoxicity biomarker. Despite the potential value of ENMAs and MN, there is scarce information about fish captured in Iberian estuaries. This is the case of the Portuguese estuaries of the Mondego, Douro and Ave, suffering from different levels of environmental stress and where chemical surveys have been disclosing significant amounts of certain pollutants. So, the aim of this study was to evaluate genotoxicants impacts and infer about the exposure at those ecosystems, using the grey mullet (Mugil cephalus) as bioindicator and considering the type and frequency of nuclear abnormalities of erythrocytes as proxies of genotoxicity. Sampling of mullets was done throughout the year in the important Mondego, Douro and Ave River estuaries (centre and north-western Portugal). The fish (total n = 242) were caught in campaigns made in spring-summer and autumn-winter, using nets or fishing rods. The sampled mullets were comparable between locations in terms of the basic biometric parameters. Blood smears were stained with Diff-Quik to assess the frequencies of six types of ENMAs and MN (given per 1,000 erythrocytes). Some basic water physicochemical parameters were recorded to search for fluctuations matching the ENMAs. Overall, the most frequent nucleus abnormality was the polymorphic type, sequentially followed by the blebbed/lobed/notched, segmented, kidney shaped, vacuolated, MN and binucleated. The total average frequency of the ENMAs ranged from 73 ‰ in the Mondego to 108 ‰ in the Ave. The polymorphic type was typically ≥50% of the total ENMAs, averaging about 51 ‰, when considering all three estuaries. The most serious lesion-the MN-in fish from Mondego and Douro had a similar frequency (≈0.38 ‰), which was significantly lower than that in the Ave (0.75 ‰). No significant seasonal differences existed as to the MN rates and seasonal differences existed almost only in the Douro, with the higher values in AW. In general, the pattern of ENMAs frequencies was unrelated with the water physicochemical parameters. Considering the data for both the total ENMAs and for each specific abnormality, and bearing in mind that values of MN in fish erythrocytes >0.3 ‰ usually reflect pollution by genotoxicants, it is suggested that mullets were likely being chronically exposed to such compounds, even in the allegedly less polluted ecosystem (Mondego). Moreover, data supported the following pollution exposure gradient: Mondego < Douro < Ave. The scenario and inferences nicely agree with the published data from chemical monitoring.

Survey of Plant Density Tolerance in U.S. Maize Germplasm

ABSTRACTA broad range of U.S. maize (Zea mays L.) germplasm was evaluated for plant density tolerance (PDT) to identify potential sources of favorable alleles and to obtain a better understanding the underlying genetics involved. Thirty‐two hybrids created using a set of inbreds representing parentage of key heterotic subgroups were evaluated at plant densities ranging from 47,000 (19,000 plants per acre [ppA]) to 133,000 plants ha−1 (54,000 ppA). Forty‐eight phenotypic traits from five categories (photosynthetic capability, plant architecture, growth responses, source–sink relationship, and general stress tolerance) as well as grain yield were evaluated in three environments that differed for levels of soil moisture availability. The relationship between plant density and grain yield was assessed for each hybrid, with a wide range of responses observed. Five hybrids showed substantial tolerance to plant densities ≥116,000 plants ha−1 based on grain yield performance. Phenotypic trait correlations revealed a subset of traits associated with grain yield across plant densities, with all five categories of traits implicated directly; the subset included leaf angle, upper stem diameter, leaf area required to produce a gram of grain, kernel rows per ear, days to canopy closure, barrenness, kernels per plant, kernel length, leaf number, upper leaf area, staygreen, zipper effect, kernels per row, and anthesis–silking interval. Analysis of gene action for grain yield across plant densities emphasized the prominence of additivity, the increasing importance of nonadditivity as plant density and environmental stress levels increased, and genotype by environment interaction. This work paves the way for further characterization of PDT through quantitative trait locus mapping and candidate gene approaches.