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231.
We describe a collection of aquatic and wetland habitats in an inland landscape, and their occurrence within a terrestrial matrix, as a “freshwater ecosystem mosaic” (FEM). Aquatic and wetland habitats in any FEM can vary widely, from permanently ponded lakes, to ephemerally ponded wetlands, to groundwater‐fed springs, to flowing rivers and streams. The terrestrial matrix can also vary, including in its influence on flows of energy, materials, and organisms among ecosystems. Biota occurring in a specific region are adapted to the unique opportunities and challenges presented by spatial and temporal patterns of habitat types inherent to each FEM. To persist in any given landscape, most species move to recolonize habitats and maintain mixtures of genetic materials. Species also connect habitats through time if they possess needed morphological, physiological, or behavioral traits to persist in a habitat through periods of unfavorable environmental conditions. By examining key spatial and temporal patterns underlying FEMs, and species‐specific adaptations to these patterns, a better understanding of the structural and functional connectivity of a landscape can be obtained. Fully including aquatic, wetland, and terrestrial habitats in FEMs facilitates adoption of the next generation of individual‐based models that integrate the principles of population, community, and ecosystem ecology.  相似文献   
232.
Representing hydrologic connectivity of non‐floodplain wetlands (NFWs) to downstream waters in process‐based models is an emerging challenge relevant to many research, regulatory, and management activities. We review four case studies that utilize process‐based models developed to simulate NFW hydrology. Models range from a simple, lumped parameter model to a highly complex, fully distributed model. Across case studies, we highlight appropriate application of each model, emphasizing spatial scale, computational demands, process representation, and model limitations. We end with a synthesis of recommended “best modeling practices” to guide model application. These recommendations include: (1) clearly articulate modeling objectives, and revisit and adjust those objectives regularly; (2) develop a conceptualization of NFW connectivity using qualitative observations, empirical data, and process‐based modeling; (3) select a model to represent NFW connectivity by balancing both modeling objectives and available resources; (4) use innovative techniques and data sources to validate and calibrate NFW connectivity simulations; and (5) clearly articulate the limits of the resulting NFW connectivity representation. Our review and synthesis of these case studies highlights modeling approaches that incorporate NFW connectivity, demonstrates tradeoffs in model selection, and ultimately provides actionable guidance for future model application and development.  相似文献   
233.
Phytoremediation is a valuable technology for mitigating soil contamination in agricultural lands, but phytoremediation without economic revenue is unfeasible for land owners and farmers. The use of crops with high biomass and bioenergy for phytoremediation is a unique strategy to derive supplementary benefits along with remediation activities. Sunflower (Helianthus annuus L.) is a high-biomass crop that can be used for the phytoremediation of polluted lands with additional advantages (biomass and oil). In this study, 40 germplasms of sunflower were screened in field conditions for phytoremediation with the possibility for oil and meal production. The study was carried out to the physiological maturity stage. All studied germplasms mopped up substantial concentrations of Pb, with maximum amounts in shoot?>?root?>?seed respectively. The phytoextraction efficiency of the germplasm was assessed in terms of the Transfer factor (TF), Metal removal efficiency (MRE) and Metal extraction ratio (MER). Among all assessed criteria, GP.8585 was found to be most appropriate for restoring moderately Pb-contaminated soil accompanied with providing high biomass and high yield production. The Pb content in the oil of GP.8585 was below the Food safety standard of China, with 59.5% oleic acid and 32.1% linoleic acid. Moreover, amino acid analysis in meal illustrated significant differences among essential and non-essential amino acids. Glutamic acid was found in the highest percentage (22.4%), whereas cysteine in the lowest percentage (1.3%). Therefore, its efficient phytoextraction ability and good quality edible oil and meal production makes GP.8585 the most convenient sunflower germplasm for phytoremediation of moderately Pb-contaminated soil, with fringe benefits to farmers and landowners.  相似文献   
234.
Introduction. Prolonged exposure to hand-transmitted vibration from grass-cutting machines has been associated with increasing occurrences of symptoms and signs of occupational diseases related to hand–arm vibration syndrome (HAVS). Methods. A cross-sectional study was carried out using an adopted HAVS questionnaire on hand–arm vibration exposure and symptoms distributed to 168 male workers from the grass and turf maintenance industry who use hand-held grass-cutting machines as part of their work. The prevalence ratio and symptom correlation to HAVS between high and low–moderate exposure risk groups were evaluated. Results. There were positive HAVS symptoms relationships between the low–moderate exposure group and the high exposure group among hand-held grass-cutting workers. The prevalence ratio was considered high because there were indicators that fingers turned white and felt numb, 3.63, 95% CI [1.41, 9.39] and 4.24, 95% CI [2.18, 8.27], respectively. Less than 14.3% of workers stated that they were aware of the occupational hand–arm vibration, and it seemed to be related to the finger blanching and numbness. Conclusion. The results suggest that HAVS is under-diagnosed in Malaysia, especially in the agricultural sectors. More information related to safety and health awareness programmes for HAVS exposure is required among hand-held grass-cutting workers.  相似文献   
235.
A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research(SAFAR) project in Delhi. We report observations of ozone(O_3), nitrogen oxides(NO_x), carbon monoxide(CO) and particulate matter(PM_2.5and PM_(10)) before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM_(10) and PM_2.5mass concentration is as high as2070 μg/m~3 and 1620 μg/m3, respectively(24 hr mean), which was about 20 and 27 times to National Ambient Air Quality Standards(NAAQS). For Diwali-2011, the increase in PM_(10) and PM_2.5mass concentrations was much less with their peaks of 600 and of 390 μg/m~3 respectively, as compared to the background concentrations. Contrary to previous reports,firework display was not found to strongly influence the NO_x, and O_3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters.  相似文献   
236.
Sulfated polysaccharides were isolated from two Tunisian fish skins grey triggerfish (Balistes capriscus) (GTSP) and smooth hound (Mustelus mustelus) (SHSP). Their chemical and physical characteristics were investigated. The Analysis of surface morphology by scanning electron microscopy of both sulfated polysaccharides displayed the same shape with netted structure. The antioxidant activities of GTSP and SHSP were evaluated using various in vitro antioxidant assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power, β-carotene bleaching inhibition assay (IC50 GTSP = 0.5 mg mL?1 and IC50 SHSP = 0.6 mg mL?1) and DNA nicking assay. Both sulfated polysaccharides exhibited good antioxidant activities. The sulfated polysaccharides showed strong angiotensin I-converting enzyme inhibitory activities (IC50 GTSP = 0.16 mg mL?1 and IC50 SHSP = 0.18 mg mL?1). These results revealed that GTSP and SHSP exhibited significant antihypertensive activities. Overall, the results indicated that grey triggerfish and smooth hound skins can be used to generate high value-added products, thus offering a valuable source of bioactive sulfated polysaccharides for application in wide range of biotechnological applications.  相似文献   
237.
Objective: The number of road traffic injuries and fatalities in Iran is high. The aim of the present study was to investigate the rate of drivers' seat belt use and a number of related factors in Kashmar, Bardaskan, and Khalilabad (Iranian Safe Communities).Methods: In 2014, driver observations were made at 48 road sites on intercity roads, main streets, side streets, and rural roads in these 3 cities.Results: A total of 10,255 vehicles were observed, with the overall rate of seat belt use being 51.8%. The rates in Kashmar, Bardaskan, and Khalilabad were 51.4, 56.3, and 47.7%, respectively. In Kashmar, the odds of seat belt use were higher among drivers who were female, older, and taxi drivers. Higher use was also found during the afternoon, and lower use was observed on rural roads. In Khalilabad the odds of seat belt use were higher among females, older drivers, taxis, and private car drivers. Seat belt use was also higher on weekends and during the morning but was significantly lower on rural roads. Similarly, in Bardaskan the odds of using a seat belt were higher among females, older drivers, taxis, and private car drivers. Seat belt use was also higher during the afternoon but was significantly lower on rural roads, in comparison to main streets and intercity roads.Conclusions: The rate of seat belt use in these 3 cities was found to be low, despite these cities being designated as International Safe Communities. Therefore, seat belt promotion programs, tougher regulations, stronger enforcement, public awareness campaigns, and more research are needed to promote seat belt use in these Iranian cities.  相似文献   
238.

Background and purpose  

Pakistan, during the last decade, has seen an extensive escalation in population growth, urbanization, and industrialization, together with a great increase in motorization and energy use. As a result, a substantial rise has taken place in the types and number of emission sources of various air pollutants. However, due to the lack of air quality management capabilities, the country is suffering from deterioration of air quality. Evidence from various governmental organizations and international bodies has indicated that air pollution is a significant risk to the environment, quality of life, and health of the population. The Government has taken positive steps toward air quality management in the form of the Pakistan Clean Air Program and has recently established a small number of continuous monitoring stations. However, ambient air quality standards have not yet been established. This paper reviews the data being available on the criteria air pollutants: particulate matter (PM), sulfur dioxide, ozone, carbon monoxide, nitrogen dioxide, and lead.  相似文献   
239.
Pyrano[3,2-c]chromene derivatives are heterocycles with a wide range of biological properties. There is actually a need for safer synthesis of heterocycles, using for instance water as a solvent. High selectivity can also be achieved by addition of surface-active reagents to form micelles. Indeed, it is presumed that water facilitates organic reactions by the hydrophobic effect, enhanced hydrogen bonding in the transition state and cohesive energy density. Here, a simple aqueous-mediated protocol is developed for the quantitative synthesis of medicinally relevant pyrano[3,2-c]chromene derivatives by the tandem reaction of readily available reagents in cetyltrimethylammonium bromide micellar media. This new method is a modification of the three-component reaction involving Knoevenagel condensation, Michael addition and cyclization reaction. Yields of 3, 4-dihydropyrano[c]chromenes ranged from 85 to 99 % at room temperature.  相似文献   
240.
Searching for new organophosphorus compounds with minimum effects on acetylcholinesterase of non-target organism especially mammals has gained an increased attention in the public concern. In this effort, the effects of some recently introduced O-ethyl phosphoramidates and benzo-1,3,2-dioxaphospholenes on rat acetylcholinesterase in different tissues have been evaluated in vivo and compared with the effects of fenitrothion, a commercial pesticide with reported moderate toxicity to mammals. The tested compounds were introduced orally in a single dose of 85?mg/kg body weight. Results indicated that the tested phosphoramidates lowered the enzyme activity to 54–69, 36–71 and 70–76% of its normal activity in serum, liver and brain, respectively. Meanwhile, the enzyme activity was depressed by fenitrothion to 11, 2 and 11% in the mentioned organs respectively. The lower anticholinesterase activity of the examined phosphoramidates than that of fenitrothion was attributed to their low hydrophobicity and low electrophilicity of their phosphorus atom, which reduces their interaction with the enzyme active site.  相似文献   
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