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21.
Environmental Geochemistry and Health - The paper presents the results of the model experiment on spring barley (Hordeum vulgare L.) grown in polluted soil. The influence of separate and combined...  相似文献   
22.
本文建立一系列758种有机化合物对大型蚤(Daphnia magna)毒性的定量结构-活性关系(QSARs)。用简化的分子线性输入系统(SMILES)代表分子结构。用CORAL(关联和逻辑)软件作为工具来开发QSAR模型。这些模型使用蒙特卡罗方法建立,依据的原理是QSAR是一个“随机事件”,假设检验一组随机数据分布在可见的训练集和不可见的验证集。检验了三组分布于可见的训练、校准、测试集中的数据以及不可见的验证集。最佳模型的预测潜能,也就是其不可见的验证集的统计特征如下:n = 87,r2 = 0.8377,RMSE = 0.564。建议和讨论了所构建模型的机械解释和适用领域。
精选自Alla P. Toropova, Andrey A. Toropov, Aleksandar M. Veselinovi?, Jovana B. Veselinovi?, Danuta Leszczynska, Jerzy Leszczynski. Monte Carlo based QSAR models for toxicity of organic chemicals to Daphnia magna. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2691–2697, November 2016. DOI: 10.1002/etc.3466
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3466/full
  相似文献   
23.
Increasing pCO2 is hypothesized to induce shifts in plankton communities toward smaller cells, reduced carbon export rates and increased roles of gelatinous zooplankton. Appendicularians, among the most numerous pan-global “gelatinous” zooplankton, continuously produce filter-feeding houses, shortcutting marine food webs by ingesting submicron particles, and their discarded houses contribute significantly to carbon fluxes. We present a first mesocosm-scale study on the effects of temperature, pCO2 and bloom structures on the appendicularian, Oikopleura dioica. There were effects of temperature and nutrients on phytoplankton communities. No shifts in functional phytoplankton groups, nor changes in particle sizes/morphotypes, known to impact appendicularian feeding, were observed under manipulated pCO2 conditions. However, appendicularian abundance was positively correlated with increased pCO2, temperature and nutrient levels, consistent with hypotheses concerning gelatinous zooplankton in future oceans. This suggests appendicularians will play more important roles in marine pelagic communities and vertical carbon transport under projected ocean acidification and elevated temperature scenarios.  相似文献   
24.
One of the important aspects of the animal social behavior is the laterality in perception of conspecifics. Spatial laterality in adult–infant interactions is usually revealed in primates as a cradling/holding bias in adults or nipple preference in infants. The origin and function of such biases, however, remain unclear. Here, we investigated spatial laterality in adult–infant pairs in beluga whales from two geographically distinct locations using aerial photography analysis. In addition, behavioral observations on individually identified mother–infant pairs at a belugas’ breeding aggregation were conducted to assess the infants’ age influence on the lateralization in pairs. A general preference of the calves to position themselves to the right of the accompanied adult was found. We failed to reveal any influence of geographical location, presence or relative position of other individuals escorting the adult–infant pair, and position of the calf along the body of the escorting adult. A significant right-sided bias in infants’ position was present in all age classes, but 2–6 months-old belugas were found to be stronger lateralized, than the newborns and 7–18 months-old calves. That may reflect age-related changes in infants’ motor and social behavior. We argue that the revealed laterality is associated with the calves’ left eye–right hemisphere preference in perceiving social stimuli, and we then discuss its possible advantages. Pronounced adult–infant spatial laterality in condition (unlike that seen in primates) when forelimbs do not directly determine subjects’ relative positioning suggests sensory lateralization alone to be the determining factor.  相似文献   
25.
The aim of this work was to validate in the field certain measurement of the heart rate alterations of the bioindicator organism Mytilus galloprovicialis as a tool for ecotoxicological biomonitoring and assessment applications related to coastal and marine environment. The latter was determined by testing the mussels according to the method of functional loading (1-hour lowered salinity stress-exposure). The time of heart rate (HR) recovery (Trec) and the coefficient of HR variation (CVHR) in a group of tested animals were used as biomarkers for the assessment of their physiological state. It was found that the values of the biomarkers in mussels from our reference location were 1.3-1.5 times lower than in mussels from differently polluted coastal areas of the Bay. The study also included an investigation of the relationship between the mussel’s cardiac rhythm characteristics and the bioaccumulation of trace elements in their soft tissues, caused by chronic pollution. The conclusion was drawn that this approach to the physiological testing of mussels could be useful in developing a rapid and low-cost method for the assessment of the health of coastal ecosystems.  相似文献   
26.
The “biosphere–climate” system is subjected to different influences (influx of anthropogenic CO2 and pollutants, deforestation, harmful land management, biological species depopulation, etc.). Therefore, the vital question arises: “Can these influences lead to irreversible negative changes in the climate–biosphere system or a global ecological catastrophe?” The possibility of irreversible changes may be not very high, but one cannot ignore it. So the main aim of our investigation is to evaluate possible consequences of human impact on the biosphere focusing on irreversible changes of it.  相似文献   
27.
We propose the wildlife premium mechanism as an innovation to conserve endangered large vertebrates. The performance‐based payment scheme would allow stakeholders in lower‐income countries to generate revenue by recovering and maintaining threatened fauna that can also serve as umbrella species (i.e., species whose protection benefits other species with which they co‐occur). There are 3 possible options for applying the premium: option 1, embed premiums in a carbon payment; option 2, link premiums to a related carbon payment, but as independent and legally separate transactions; option 3, link premiums to noncarbon payments for conserving ecosystem services (PES). Each option presents advantages, such as incentive payments to improve livelihoods of rural poor who reside in or near areas harboring umbrella species, and challenges, such as the establishment of a subnational carbon credit scheme. In Kenya, Peru, and Nepal pilot premium projects are now underway or being finalized that largely follow option 1. The Kasigau (Kenya) project is the first voluntary carbon credit project to win approval from the 2 leading groups sanctioning such protocols and has already sold carbon credits totaling over $1.2 million since June 2011. A portion of the earnings is divided among community landowners and projects that support community members and has added over 350 jobs to the local economy. All 3 projects involve extensive community management because they occur on lands where locals hold the title or have a long‐term lease from the government. The monitoring, reporting, and verification required to make premium payments credible to investors include transparent methods for collecting data on key indices by trained community members and verification of their reporting by a biologist. A wildlife premium readiness fund would enable expansion of pilot programs needed to test options beyond those presented here. Mejora de la Conservación, Servicios del Ecosistema y Calidad de Vida Local Mediante un Mecanismo de Compensación de Vida Silvestre  相似文献   
28.
All stages of vertical transmission of symbiotic bacteria, from the penetration into oocytes to the formation of rhagon, were investigated in the White Sea (Arctic) representatives of Halisarca dujardini Johnston (Demospongiae). Small populations of free-living specific symbiotic bacteria inhabit the mesohyl of H. dujardini. They are represented by a single morphotype of small spiral gram-positive bacteria. Vertical transmission of symbiotic bacteria between generations in sponges may occur in different ways. In the case of H. dujardini the bacteria penetrate into growing oocytes by endocytosis. A part of the bacteria plays a trophic role for oocytes and the other part remains undigested in membrane-bound vacuoles within the cytoplasm. In cleaving embryos bacteria are situated between the blastomeres or in the vacuoles. In the blastula all bacteria are disposed in the blastocoel. The symbionts are situated in intercellular spaces in free-swimming larvae and during metamorphosis. Symbiotic bacteria do not play any trophic role in the period of embryonic and postembryonic development of H. dujardini. No signs of destruction and digestion of bacteria were revealed at any stage of development.Communicated by O. Kinne, Oldendorf/Luhe  相似文献   
29.
Successful migration for passerine birds depends largely on the quality of stopover habitats, but we still lack complete knowledge of how migrants search for habitats en route and how they behave when landing at poor quality stopover sites. We compared the distance of exploratory movements and stopover durations of the reed warbler Acrocephalus scirpaceus, a reedbed habitat specialist, released at suitable (reed bed) and unsuitable (sand dune) stopover sites. Birds tape-lured during nocturnal migration to a sand dune were captured, radio-tagged, released and tracked at two sites of contrasting habitat quality. Lean birds were found to move further in the dunes (max. 300 m) than in reeds (max. 200 m), whereas ‘fat’ individuals at both sites remained stationary. Birds spent just 1 day in the dunes and up to 13 days in the reeds. Our results suggest that some nocturnal migrants with restricted diurnal exploratory movements depend on stopover site selection when ceasing nocturnal flight.  相似文献   
30.
Symbiotic bacteria from six Oscarella species (adults and embryos) collected in the Mediterranean Sea (O. lobularis, O. tuberculata, O. imperialis, O. microlobata, O. viridis) and the Sea of Japan (O. malakhovi) were investigated by scanning electron microscopy and transmission electron microscopy. In most cases, symbionts are rather numerous. Each sponge species has a definite set of bacterial morphological types. All bacteria are extracellular. Symbionts occupy the mesohyl of adult sponges or intercellular space in embryos and are often in contact with mesohylar filaments or cells. Bacteria of some morphotypes have characteristic blebs. Most symbionts are gram-negative, and two types of bacteria have traits of Archaea and one type of bacteria is similar to Planctomycetes. Data on morphology of bacterial symbionts can be a good additional character for identification of Oscarella species, which have no skeleton.  相似文献   
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