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251.
Recognition and understanding of landscape dynamics as a historical legacy of disturbances are necessary for sustainable management
of forest ecosystems. This study analyzed spatial and temporal changes in land use and land cover patterns in a typical mountain
watershed in the Gumushane district along the Northeastern part of Turkey. The area is investigated by comparing LANDSAT images
from 1987 to 2000 and evaluated the temporal changes of spatial structure of forest conditions through spatial analysis of
forest cover type maps from 1971 and 1987 using GIS and FRAGSTATS™.
The results show a general decreasing trend in area of natural land cover types including broadleaf and conifer forests as
well as coppice between 1971 and 1987 (0.54%, respectively). In contrast, between 1987 and 2000 this natural land cover types
show increasing trend (1.6%). In parallel with forest dynamics, the area of managed land including lowland and upland agricultural
areas, rangelands and grasslands increased during the first period and decreased during second period. In terms of spatial
configuration, Gümüşhane forests aren’t generally fragmented by intensive forest utilization in the latter periods. This is
partially due to out-migration of rural population in Gümüşhane. Nevertheless, land use pattern significantly changed over
time depending on a few factors such as unregulated management actions, social pressure and demographic movements. The study
revealed that demographic movements have a major effect on landscape dynamics. 相似文献
252.
Taha Ahmed Elmukashfi Isam Mohamed ElkhidirOmer Ali Ibrahim Abdelgadir Ali BashirMohammed Ali Awad Elkarim 《Safety Science》2012,50(5):1215-1217
Background
Hepatitis B virus (HBV) infection is a global public health problem. It is estimated that there are more than 300 million HBV carriers in the world.Aim
The study aimed to examine the sero-prevalence of hepatitis B virus (HBV) markers among health care workers (HCWs) in Public Teaching Hospitals in Khartoum State, in the year 2004.Methods
The study is an observational, cross sectional, facility-based study. It was conducted on stratified two-stage cluster random sample of 843 subjects. The study followed non-parametric statistical methods, using Z-test for single proportion.Results
Among the 843 subjects tested for all HBV markers (Anti-HBc, HBsAg, HBsAb, and HBeAg), the prevalence of Anti-HBc, HBsAg, HBsAb, and HBeAg was found to be 57% (CI 95%:53-60%), 6% (CI 95%:4.0-8.0%), 37% (CI 95%:34-40%) and 9% (CI 95%:7-11%) respectively. P < 0.05.Conclusion
Seroprevalence of all HBV markers (P < 0.05) was found to be significantly high, while the rate of immunity against HBV infection was low among health care workers In Public Teaching Hospitals in Khartoum State, Sudan. 相似文献253.
在当今世界,电力、能源和安全是人们日常生活的基本要求。为了应对日益增长的能源需求,最终的解决办法是实施可再生能源,然后将其用于人类的安全。可再生能源需要以它们各自正确的方式实施。研究基于压电传感器片的迈步发电装置,并演示了如何利用这些能量实现建筑物疏散照明。我们在传感器的下方和顶部分别固定了木板和可移动网螺栓,利用压电传感器系统,行人可以通过迈步向发电装置施加电能,另外,将硅凝胶粘贴在位于下部木板空洞中的所有传感器顶部。当有人踩到板上时,就会自动施加压力。在木板的顶部和底部设置了一个孔,以便随时调整在底部和顶板之间安装的可移动网螺栓。烟雾传感器用于启动灯光。使用这种设备,我们实现了建筑物疏散路径上的LED灯正常运行。结果表明,这种安全发电的设计和方法具有一定的实用价值,同时也满足了全球对能源的需求。 相似文献
254.
Neda Mahdavi Ali Ashraf Jamshidi Ebrahim Darvishi Abbas Moghimbeygi Rashid Heidari Moghadam 《International journal of occupational safety and ergonomics》2018,24(1):41-51
Introduction. Shoulder disorders are one of the most prevalent musculoskeletal disorders among carpet weavers. The most important cause of these disorders is muscle fatigue. The aim of the present study is to investigate the effect of carpet weaving characteristics on upper trapezius (UTr) muscle fatigue during a task cycle. Method. In this cross-sectional study, 9 women and 3 men participated. During an 80-min cycle of carpet weaving, a times-series model was applied to assess electromyography amplitude and frequency changes. Result. According to the joint analysis of electromyogram spectrum and amplitude method, the participants experienced 0% force decrease, 0.9% recovery, 18% force increase and 72% fatigue in the left UTr. Furthermore, the rates of force decrease, recovery, force increase and fatigue in the right UTr were 18%, 18%, 18% and 45%, respectively. Fatigue in the right and the left UTr was reported to be the dominant state during one carpet weaving task cycle. Conclusion. Task cycle appears to have a significant impact on UTr fatigue in participants, and UTr fatigue can be considered a serious risk factor in shoulder musculoskeletal disorders. Hence, further studies should focus on better workstations and work–rest periods during various subtasks. 相似文献
255.
256.
Ali Erturk Melike Gurel Alpaslan Ekdal Cigdem Tavsan Aysegul Ugurluoglu Dursun Zafer Seker Aysegul Tanik Izzet Ozturk 《Journal of environmental management》2010,91(7):1526-1545
Istanbul, being one of the highly populated metropolitan areas of the world, has been facing water scarcity since the past decade. Water transfer from Melen Watershed was considered as the most feasible option to supply water to Istanbul due to its high water potential and relatively less degraded water quality. This study consists of two parts. In the first part, water quality data covering 26 parameters from 5 monitoring stations were analyzed and assessed due to the requirements of the “Quality Required of Surface Water Intended for the Abstraction of Drinking Water” regulation. In the second part, a one-dimensional stream water quality model with simple water quality kinetics was developed. It formed a basic design for more advanced water quality models for the watershed. The reason for assessing the water quality data and developing a model was to provide information for decision making on preliminary actions to prevent any further deterioration of existing water quality. According to the water quality assessment at the water abstraction point, Melen River has relatively poor water quality with regard to NH4+, BOD5, faecal streptococcus, manganese and phenol parameters, and is unsuitable for drinking water abstraction in terms of COD, PO43?, total coliform, total suspended solids, mercury and total chromium parameters. The results derived from the model were found to be consistent with the water quality assessment. It also showed that relatively high inorganic nitrogen and phosphorus concentrations along the streams are related to diffuse nutrient loads that should be managed together with municipal and industrial wastewaters. 相似文献
257.
E. Safari M. Jalili Ghazizade M.A. Abduli B. Gatmiri 《Waste management (New York, N.Y.)》2014,34(8):1408-1415
Performance of compacted clay liners commonly used as landfill barrier systems can be subject to decline in terms of hydraulic conductivity if left exposed to atmospheric conditions for an extended period of time prior to placement of overlaying layers. The resulting desiccation cracking can lead to increased hydraulic conductivity. Desiccation crack intensity was studied for three clayey soils commonly used for construction of landfill barrier system in a relatively large scale test setup exposed to real time atmospheric conditions over a complete annual cycle. A white separator geotextile cover was presumed to be capable of reducing the intensity of desiccation cracking through absorbing and maintaining higher amounts of moisture and reducing the temperature of the soil surface in comparison to a directly exposed soil surface. Desiccation cracking was monitored using a digital imaging technique for three compacted clay liners in two sets, one open to air and the second covered with the white geotextile. Crack intensity factor approached a relatively stable phase after certain cycles corresponding to atmospheric dry wet cycles. The results indicated that the white separator geotextile was capable of reducing the crack intensity factor by 37.4–45.9% throughout the experiment including the cyclic phase of desiccation cracking. During the stable phase, the maximum reduction in crack intensity factor of 90.4% as a result of applying geotextile cover was observed for the soil with the lowest plastic index and clay content and therefore the lowest magnitude of crack intensity factor. The other two soils with similar clay content but different plastic index showed 23.6% and 52.2% reductions in crack intensity factor after cyclic phase when covered with geotextile. 相似文献
258.
Managing Mediterranean soil resources under global change: expected trends and mitigation strategies
Lagacherie Philippe Álvaro-Fuentes Jorge Annabi Mohamed Bernoux Martial Bouarfa Sami Douaoui Abdelkader Grünberger Olivier Hammani Ali Montanarella Luca Mrabet Rachid Sabir Mohammed Raclot Damien 《Regional Environmental Change》2018,18(3):663-675
Regional Environmental Change - The soils of the Mediterranean Basin are the products of soil processes that have been governed by a unique convergence of highly differentiated natural and... 相似文献
259.
Mounir Ben Mbarek Nadia Ben Ali Rochdi Feki 《Environment, Development and Sustainability》2014,16(6):1253-1262
This article analyzes the causality between the economic growth, the energy and the environment, measured by CO2 emissions. Our empirical study is based on a series of annual data from 1980 to 2010 in Tunisia. Our study was conducted using the Granger causality test and variance decomposition. The empirical results confirm the presence of a positive effect between the energy consumption and the economic growth measured by gross domestic product (GDP). Thus, there is a unidirectional relationship between GDP and CO2 emissions in the short term. This analysis shows, as is common to relatively fast-growing economies in Tunisia, that the biggest contributor to the rise is CO2 emissions. Hence, in congruence with the result of variance decomposition, the GDP affects CO2 emissions in the short and medium term at an almost constant level (10 %). The non-renewable energy intensity in Tunisian economy is responsible for a modest reduction in CO2 emissions, which suggests the implementation of conservation policies aimed at energy efficiency and the orientation toward renewable energy. 相似文献
260.
Keshavarzi B Moore F Najmeddin A Rahmani F Malekzadeh A 《Environmental geochemistry and health》2012,34(1):15-26
Golestan province in north Iran is known to be a high-risk area for esophageal cancer (EC). Of a long list of multiple risk
factors, this study focuses on a possible link between the epidemiologic patterns of EC and the anomalous concentration of
some ions and elements in the drinking water sources. A total of 183 samples from 45 villages covering a wide range of EC
mortality rates are collected and analyzed. The results demonstrate that NO3
−, SO4
2−, Sb, and Sr exceed the recommended maximum concentration level (MCL) in drinking water. This is more prominent in the villages
with high esophageal cancer mortality rate, suggesting a possible link between EC incidence and water quality. Se concentration
in drinking water increases from low to the high EC areas, a finding contrary to the expected trend. It is concluded that
Se deficiency does not play a major role in the etiology of EC in the Golestan province. The statistical results obtained
from Mann–Whitney and Kruskal–Wallis tests along with cluster analysis are consistent with the observed trend of EC mortality
rate in Golestan province. 相似文献