Population evacuation: evaluating spatial distribution of flood shelters and vulnerable residential units in Dhaka with geographic information systems   总被引：2，自引：1，他引：1  

Akiko Masuya  Ashraf Dewan  Robert J. Corner 《Natural Hazards》2015,78(3):1859-1882

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Quantifying climate-induced drought risk to livelihood and mitigation actions in Balochistan     

Ashraf  Muhammad  Arshad  Adnan  Patel  Praharsh M.  Khan  Adeel  Qamar  Huma  Siti-Sundari  Ristina  Ghani  Muhammad Usman  Amin  Ali  Babar  Jamilur Rehman 《Natural Hazards》2021,109(3):2127-2151

Natural Hazards - Climate change-induced disasters show the highest risk for agriculture and livelihoods in rural areas of developing countries. Due to changing rainfall pattern, the arid and...  相似文献   

Satellite remote sensing for mapping vegetation in New Zealand freshwater environments: A review     

Salman Ashraf  Lars Brabyn  Brendan J. Hicks  Kevin Collier 《New Zealand geographer》2010,66(1):33-43

Freshwater environments in New Zealand provide a range of ecosystem services and contain important biodiversity. Managing these environments effectively requires a comprehensive inventory of the resource and cost-effective tools for regular monitoring. The complex and extensive margins of natural water bodies make them difficult to sample comprehensively. Problems thus occur with extrapolating point-specific sampling to accurately represent the diversity of vegetation in large freshwater bodies. Mapping freshwater vegetation using satellite remote sensing can overcome problems associated with access, scale and distribution, but it requires high-resolution images that have appropriate spectral characteristics. This paper provides an overview of the optical satellite data characteristics required for mapping riparian, submerged and emergent vegetation associated with freshwater environments in New Zealand.  相似文献   

Gas and fluid venting at the Makran accretionary wedge off Pakistan   总被引：2，自引：1，他引：1  

U. von Rad  U. Berner  G. Delisle  H. Doose-Rolinski  N. Fechner  P. Linke  A. Lückge  H. A. Roeser  R. Schmaljohann  M. Wiedicke  SONNE / Scientific Parties  M. Block  V. Damm  J. Erbacher  J. Fritsch  B. Harazim  J. Poggenburg  G. Scheeder  B. Schreckenberger  N. von Mirbach  M. Drews  S. Walter  A. Ali Khan  A. Inam  M. Tahir  A. R. Tabrez  A. H. Cheema  M. Pervaz  M. Ashraf 《Geo-Marine Letters》2000,20(1):10-19

The Makran accretionary complex shows a distinct bottom-simulating reflector, indicating a thick gas-hydrate-bearing horizon between the deformational front and about 1350 m water depth which seals off the upward flow of gas-charged fluids. A field of presently inactive mud diapirs with elevations up to 65 m was discovered in the abyssal plain seawards of the deformation front, suggesting that in the past conditions were favorable for periodic but localized vigorous mud diapirism. Regional destabilization of the gas hydrate leading to focused flow was observed where deep-penetrating, active faults reach the base of the gas-hydrate layer, as in a deeply incised submarine canyon (2100–2500 m water depth). At this location we discovered seeps of methane and H₂S-rich fluids associated with chemoautotrophic vent faunas (e.g., Calyptogena sp.). Driven by the accretionary wedge dynamics, the landward part of the gas-hydrate layer below the Makran margin is being progressively uplifted. Due to reduced hydrostatic pressure and rising ocean bottom-water temperatures, gas hydrates are progressively destabilized and dissociated into hydrate water, methane and H₂S. Sediment temperatures lie outside the methane stability field wherever water depth is less than 800 m. Above this depth, upward migration of fluids to the seafloor is unimpeded, thus explaining the abundance of randomly distributed gas seeps observed at water depths of 350 to 800 m. Received: 14 June 1999 / Revision accepted: 6 February 2000  相似文献   

Probabilistic seismic hazard model for Cairo,Egypt: estimates and uncertainties     

Ashraf Adly  Laurentiu Danciu  Donat Fäh  Valerio Poggi  Awad Omran  Awad Hassoup 《Bulletin of Earthquake Engineering》2018,16(12):5697-5733

A new seismic hazard model for Cairo, the capital city of Egypt is developed herein based on comprehensive consideration of uncertainties in various components of the probabilistic seismic hazard analysis. The proposed seismic hazard model is developed from an updated catalogue of historical and instrumental seismicity, geodetic strain rates derived from GPS-based velocity-field of the crust, and the geologic slip rates of active faults. The seismic source model consists of area sources and active faults characterised to forecast the seismic productivity in the region. Ground motion prediction models are selected to describe the expected ground motion at the sites of interest. The model accounts for inherent epistemic uncertainties of statistical earthquake recurrence; maximum magnitude; ground motion prediction models, and their propagation toward the obtained results. The proposed model is applied to a site-specific hazard analysis for Kottamiya, Rehab City and Zahraa-Madinat-Nasr (hereinafter referred to as Zahraa) to the East of Cairo (Egypt). The site-specific analysis accounts for the site response, through the parameterization of the sites in terms of average 30-m shear-wave velocity (Vs30). The present seismic hazard model can be considered as a reference model for earthquake risk mitigation and proper resilience planning.  相似文献   

Evaluating severity–area–frequency (SAF) of seasonal droughts in Bangladesh under climate change scenarios     

Alamgir  Mahiuddin  Khan  Najeebullah  Shahid  Shamsuddin  Yaseen  Zaher Mundher  Dewan  Ashraf  Hassan  Quazi  Rasheed  Balach 《Stochastic Environmental Research and Risk Assessment (SERRA)》2020,34(2):447-464

Stochastic Environmental Research and Risk Assessment - Drought is considered to be one of the most devastating natural hazards, causing widespread environmental and social damage in many parts of...  相似文献   

Response of streamflow to climate variability in the source region of Jhelum River Basin in Kashmir valley,India     

ul Shafiq  Mifta  Ashraf  Ifra  ul Islam  Zahoor  Ahmed  Pervez  Dimri  A. P. 《Natural Hazards》2020,104(1):611-637

Natural Hazards - Successful management of the water resources directly depends on our understanding of the heterogeneity of changing climate and consequent response of annual and seasonal...  相似文献   

Floc meal as potential substitute for soybean meal in tilapia diets under biofloc system conditions     

Rania S. MABROKE  Osama M. EL-HUSSEINY  Abd El-Naem F. A. ZIDAN  Al-Azab TAHOUN  Ashraf SULOMA 《海洋湖沼学报（英文）》2019,(1):313-320

This study was conducted to evaluate the ef fect of replacing soybean meal(SBM) by low protein ?oc meal(LPFM; 24% CP) in tilapia diets on growth performance, feed utilization and ?sh chemical composition. Three isonitrogenous and isocaloric diets were formulated; control diet(C; without LPFM),FM 25(25% of SBM protein was substituted by LPFM) and FM 50(50% of SBM protein was substituted by LPFM). Nine 55 l circular plastic tanks were stocked by 12 ?sh to form three experimental groups.No dif ferences in tilapia performance were observed between the control and the FM 25 diet. Chemical composition of ?sh did not dif fer signi?cantly among treatments except for protein and selenium contents where the highest values were recorded in the control treatment. The highest mineral content was recorded in ?oc collected from the control tanks, while calcium content showed its highest value in ?oc collected from FM 50 e ? uent. These data indicate that replacing soybean meal with LPFM up to 25%, had no negative ef fect on growth performance and potentially may improve the system sustainability. Meanwhile, the adverse ef fect of more inclusion of LPFM in tilapia diet may be attributed to the higher content of ash. In other word,minerals seem to cause more energy utilization in ?sh fed ?oc meal since it is needed to maintain osmotic homeostasis.  相似文献   

Floc meal as potential substitute for soybean meal in tilapia diets under biofloc system conditions     

Mabroke  Rania S.  El-Husseiny  Osama M.  Zidan  Abd El-Naem F. A.  Tahoun  Al-Azab  Suloma  Ashraf 《中国海洋湖沼学报》2019,37(1):313-320

This study was conducted to evaluate the effect of replacing soybean meal (SBM) by low protein floc meal (LPFM; 24% CP) in tilapia diets on growth performance, feed utilization and fish chemical composition. Three isonitrogenous and isocaloric diets were formulated; control diet (C; without LPFM), FM ₂₅ (25% of SBM protein was substituted by LPFM) and FM ₅₀ (50% of SBM protein was substituted by LPFM). Nine 55l circular plastic tanks were stocked by 12 fish to form three experimental groups. No differences in tilapia performance were observed between the control and the FM ₂₅ diet. Chemical composition of fish did not differ significantly among treatments except for protein and selenium contents where the highest values were recorded in the control treatment. The highest mineral content was recorded in floc collected from the control tanks, while calcium content showed its highest value in floc collected from FM ₅₀ effluent. These data indicate that replacing soybean meal with LPFM up to 25%, had no negative effect on growth performance and potentially may improve the system sustainability. Meanwhile, the adverse effect of more inclusion of LPFM in tilapia diet may be attributed to the higher content of ash. In other word, minerals seem to cause more energy utilization in fish fed floc meal since it is needed to maintain osmotic homeostasis.

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基于图像相减和随机森林的AST3巡天暂现源及变源搜寻方法          下载免费PDF全文

黄天君  孙天瑞  胡镭  宁宗军  吴雪峰  王力帆  王晓峰  朱镇熹  UDDIN Ashraf Sye  ASHLEY Charles Brewster Michael 《天文学报》2019,60(5):98-114

AST3-2 (Antarctic Survey Telescopes)光学巡天望远镜位于南极大陆最高点冰穹A,其产生的大量观测数据对数据处理的效率提出了较高要求.同时南极通信不便,数据回传有诸多困难,有必要在南极本地实现自动处理AST3-2观测数据,进行变源和暂现源观测的数据处理,但是受到低功耗计算机的限制,数据的快速自动处理的实现存在诸多困难.将已有的图像相减方案同机器学习算法相结合,并利用AST3-2 2016年观测数据作为测试样本,发展一套的暂现源及变源的筛选方法成为可行的选择.该筛选方法使用图像相减法初步筛选出可能的变源,再用主成分分析法抽取候选源的特征,并选择随机森林作为机器学习分类器,在测试中对正样本的召回率达到了97%,验证了这种方法的可行性,并最终在2016年观测数据中探测出一批变星候选体.  相似文献