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201.
Great barracuda (Sphyraena barracuda) were implanted with acoustic telemetry transmitters (n = 42) and monitored within a stationary acoustic receiver array (n = 53 receivers) in The Bahamas to examine residency, seasonal movements, and habitat use. Barracuda were monitored for up to 980 days and remained within the array area ~33% (median value) of the time. Most tagged barracuda were transient and would often disappear from the array for months at a time, particularly in the summer where they were usually last detected on receivers located in deeper shelf habitats, and then return at other times in the year. Habitat use across the footprint of the array differed, with most detections occurring in coastal areas and comparatively fewer in deeper mosaic or shelf habitats. Linear home range estimates revealed that some barracuda moved >12 km within a single day and are capable of migrating >100 km to other islands in the Bahamian Archipelago. Our results provide some of the first telemetry data for this apex marine predatory fish and the first reliable information on the residency and localized seasonal movements of adult great barracuda in the coastal waters of the Western Atlantic.  相似文献   
202.
为研究荷木(Schima superba)个体间树干CO2释放通量(Es)的差异以及树干液流对Es的影响,提高森林生态系统呼吸计算准确性,利用红外气体分析仪及自制式气室于2009年湿季和干季监测了华南荷木人工林5棵样树的Es,并同步监测了树干温度(θs)、气温及液流密度.结果显示:θs与气温之间呈显著线形正相关;Es与树干温度之间存在显著指数函数关系;Es干湿季的差异显著,并呈现明显的季节变化;5株样树之间Es存在显著差异,平均Es分别为3.12、3.60、5.52、6.98、8.09μmol m-2 s-1;同时,样树之间树干CO2释放通量的温度系数(Q10)差异显著(1.97~4.24之间).Tree1、Tree2和Tree4白天的Es与液流速度(v)显著正相关,白天的标准化树干CO2释放通量(R25,温度为25℃时的Es)高于晚上.荷木Es个体之间及时间上的差异主要受树干温度、生长状况和液流速度的影响.图3表6参35  相似文献   
203.
中国农业领域温室气体主要减排措施研究分析   总被引:9,自引:0,他引:9  
气候变暖已成不争事实,主要是由于人为温室气体(GHG)排放增加所致,为减缓气候变暖趋势,各领域迫切需要采取减排措施;农业是一个重要的GHG排放源,农业领域采取减排措施对于减少我国GHG排放、保护农村生态环境有重要意义。文章在大量阅读前人研究结果的基础上,总结我国农业领域主要的减排管理措施,主要从农业活动、农村生活和生物质能源利用三方面进行阐述,并简要分析各措施的减排效果和存在问题。分析发现,农业活动的水肥管理是农田温室气体减排的研究热点,但由于地域和管理流程上的差异,对措施的减排效果尚存在争议;农村生活中存在巨大的减排潜力,采取恰当的减排措施不但可以减少GHG排放,还可以改善农村生态状况和环境卫生条件;农村生物质能源有很大发展潜力,合理开发利用,可以有效替代化石能源消耗,缓解能源危机,减少GHG排放,保护生态环境。总之,在农业领域采取积极的减排措施,有助于国家效应对气候变化,降低农业源污染和GHG排放,减轻环境压力,转换农业发展模式,加速农业现代化,促进农业生产的可持续发展和社会主义新农村建设。  相似文献   
204.
Effects of an office ergonomics workplace and training intervention on workers’ knowledge and self-reported musculoskeletal pain and discomfort were investigated. An instructional systems design process was used to develop an office ergonomics training program and the evaluation tools used to measure the effectiveness of the training program on workers’ office ergonomics knowledge and skills. It was hypothesized that the training and workplace intervention would allow the worker to more effectively use their workplace through increased office ergonomics knowledge and skills. Following the intervention, there was a significant increase in workers’ office ergonomics knowledge and awareness. Self-reported work-related musculoskeletal disorders significantly decreased for the group who had a workplace change and received ergonomic training relative to a workplace change-only group and a no intervention control group.  相似文献   
205.
Many mathematical programs have been developed over the past 50 years to aid agricultural experts and other farming decision-makers. The application of these mathematical programs has seen limited success because their development has focused on mathematical theory as opposed to the requirements needed for application. This paper describes the development of two mathematical programs that were designed to integrate with a visualization simulation that aids a nontraditional group of agricultural decision-makers: illiterate Sri Lankan subsistence farmers. The simulation was designed to help these illiterate farmers make business decisions about their crop selection choices which, in turn, will help them develop their business plans required for obtaining bank micro-loans. This paper’s focus is on the use of linear programming as a potential tool to demonstrate the benefits of crop diversification and rotation to the farmer based on various available crop types. It also highlights the issues using such an approach.  相似文献   
206.
A comparative study of the seed progeny of dandelions was performed with samples from cenopopulations growing for a long time under conditions of radioactive contamination (the zone of the Eastern Ural Radioactive Trace, EURT) or chemical pollution (the impact zone of the Nizhnii Tagil Metallurgical Plant, NTMP). The viability of seeds proved to decrease in a similar way along with an increase in technogenic pressure, irrespective of its nature. Experiments on acute exposure to heavy metals and γ-irradiation made it possible to reveal the adaptive capacities of the seed progeny from each cenopopulation. The background sample (formed beyond the zone of any impact) was relatively resistant to irradiation and very sensitive to heavy metals. The cenopopulations from the EURT and NTMP zones manifested nonspecific responses to the effects of both habitual and new factors.  相似文献   
207.
Study of the seasonal variation of the sex ratio in the honeybee mite Varroa jacobsoni demonstrated that sex determination was affected by temperature, order of reproductive cycles, and population densities in the host’s brood cell and the honeybee nest. The mechanism of reproduction ensuring adaptation of the mite to parasitism and reproduction on honeybees are discussed.  相似文献   
208.
The spatial distribution of coarse woody debris in pine forests has been studied in the Transvolga region of the Marii El Republic. For this purpose, 30 test plots have been established in pine (Pinus sylvestris) stands of the study region. The results are indicative of a tendency toward the spatial grouping (clustering) of woody debris by fractions, decomposition classes, and stocks along with increase in stand age.  相似文献   
209.
On the basis of Annals of Nature of the Prioksko-Terrasnyi Biosphere Reserve, its colonization by invasive mammal species and the current state of their populations have been analyzed. In the mammal fauna of the reserve, 13 out of 60 species can be classified as invasive. They differ in the degree of impact on the biota. The house mouse, Norway and black rats, and European bison have virtually no effect on natural ecosystems; the effect of the muskrat, raccoon dog, American mink, red and axis deer is insignificant; and that of stray dogs and Tartarian roe deer is considerable. The European beaver and wild boar play an environment-forming role. The impact of beaver activities is strong but local, whereas activities of wild boars put into question the very possibility of conservation and analysis of representative biosphere areas and biological diversity in the reserve.  相似文献   
210.
This paper describes the derivation of an Environmental Emissions Index (EEI) intended to quantify the environmental performance of Integrated Pollution Prevention and Control (IPPC) installations and sectors. Characterisation and normalisation methods used in lifecycle analyses were applied to 20 routinely reported emissions parameters, pertaining to six environmental impact categories. Distance to policy targets for relevant emissions were used to weight impact categories, and link the EEI to policy priorities. Ireland and the EU15 were considered as scales of context. The European Pollutant Emission Register was a convenient source of normalisation data, but restricted the context of the EEI to industrial emissions, and distorted outputs. Using national and EU15 total loading estimates for normalisation resulted in an EEI that better reflected the relative contribution of reported emissions towards overall environmental pressures. Using Ireland's pharmaceutical sector as a case study indicated that weighting factors, and the toxicity range of NMVOC emissions, were the largest sources of EEI uncertainty. Through the integration of inventory data, scientific characterisation, and policy targets, the EEI translates reported emissions data from IPPC installations and sectors into a benchmark of environmental performance. It may be regarded as an evolving tool of potential utility to regulators and policy makers.  相似文献   
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