应用CEDA和ASPIC软件包对巴基斯坦国的多齿蛇鲻(Saurida tumbil)渔业的最大持续产量的初步研究     

KALHORO Muhsan Ali  LIU Qun  MEMON Khadim Hussain  WARYANI Baradi  SOOMRO Shamsher Hyder 《海洋学报(英文版)》2015,34(2):68-73

The catch and effort data analysis(CEDA) and ASPIC(a stock assessment production model incorporating covariates) computer software packages were used to estimate the maximum sustainable yield(MSY) from the catch and effort data of Greater lizardfish Saurida tumbil fishery of Pakistan from 1986 to 2009. In CEDA three surplus production models of Fox, Schaefer and Pella-Tomlinson were used. Here initial proportion(IP) of 0.5 was used because the starting catch was roughly 50% of the maximum catch. With IP = 0.5, the estimated MSY from Fox model were 20.59 mt and 38.16 mt for normal and log-normal error assumptions, while the MSY from Schaefer and Pella-Tomlinson were 60.40, 60.40 and 60.40 mt, for normal, log-normal and gamma error assumptions respectively. The MSY values from Schaefer and Pella-Tomlinson models of three error assumptions were the same. The R2 values from those three models were above 0.6. When IP = 0.5, the MSY values estimated from ASPIC from Fox were 132 mt, and from logistic model were 69.4 mt, with R2 value above 0.8. Therefore we suggest the MSY of S. tumbil fishery from Pakistan to be 60–70 mt, which is higher than the latest catch, thus we would recommend that the fishing efforts for this fishery may be kept at the current level.  相似文献   

The scarp lands of Saudi Arabia     

Randolf Rausch  Theo Simon  Hussain Al Ajmi  Heiko Dirks 《Arabian Journal of Geosciences》2014,7(6):2437-2450

In central Saudi Arabia, the combination of rock types and sedimentary bedding created a unique scarp landscape. The escarpments were formed during Late Miocene through Early Quaternary times. At present, cuesta formation and migration are restricted to the actual escarpments as a consequence of negligible sediment removal. The plains between the escarpments are sealed through periodically active fluvial processes and through eolian sedimentation. In this publication, the major escarpments of central Saudi Arabia are described. The interactions between tectonics, climate, and morphogenesis which created this unique landscape are reviewed.  相似文献   

Method Development and Optimisation of Sodium Peroxide Sintering for Geological Samples          下载免费PDF全文

Syed Nadeem Hussain Bokhari  Thomas C. Meisel 《Geostandards and Geoanalytical Research》2017,41(2):181-195

This work provides a measurement procedure for the complete digestion of rock samples containing refractory minerals such as zircon and chromite. Their dissolution by wet acid digestion is often incomplete but, although providing complete digestions, alkali fusion techniques can result in solutions with a high blank and total dissolved solid content. It was established by the systematic study with reference material trachyandesite MTA‐1 that a 1:6 sample to sodium peroxide (Na₂O₂) ratio is conservative for the complete digestion and recovery of all the analytes especially those contained in zircon. The sample decomposition time was 120 min for the zircon‐bearing rhyolite reference material MRH‐1. Complete digestion of chromite was obtained in the harzburgite RM MUH‐1. The sample solutions were stable for at least 1 year. Accurate measurements of SiO₂, Al₂O₃, TiO₂, P₂O₅ and K₂O could be made with ICP‐MS by not discarding the supernatant of the sinter solution and by using geological reference materials for external calibration. HF digestions are slow, not universal, and may form new mineral/phases that are insoluble under high temperature conditions. The validated sample decomposition procedure combined with ICP‐MS presents an alternative to the use of HF in routine analysis of difficult to digest geological materials.  相似文献   

Hydrochemical characteristics and evaluation of the granite aquifer in the Alwadeen area,southwest Saudi Arabia     

Sattam Almadani  Hussain Alfaifi  Abdullah Al-Amri  Mohamed Fnais  Elkhedr Ibrahim  Kamal Abdelrahman  Mohammed Shehata  Faisal Zaidi 《Arabian Journal of Geosciences》2017,10(6):139

This study was carried out in the Alwadeen area of Khamis Mushayt district of southwestern Saudi Arabia to evaluate the hydrochemical characteristics of the shallow hard rock aquifers. These hard rock aquifers mostly comprise granites and contain significant quantities of groundwater that complement the available groundwater from the unconsolidated alluvial sediments in the nearby wadis. The field investigation indicates two main fracture sets which intersect each other and are oriented in the west-northwest and east-west directions. The granitic rocks in the area are intruded by coarse-grained and quartz-rich monzogranite and pegmatite veins. Hydrogeologically, the fracture systems are important since they facilitate the groundwater storage and assume the transmissive function during times of groundwater abstraction. Given the fact that groundwater in the fractured rock aquifers generally occurs at shallow depths, it may be exposed to contamination from surface and/or near-surface sources, and it is therefore important to evaluate its quality. To this end, a hydrochemical analysis was carried out on six groundwater samples collected from the area. The hydrochemistry revealed that the groundwater is fairly fresh, and facies analysis reveals mixed Na-Cl and Ca-Mg-Cl-SO₄ types. Overall, the results reveal that the groundwater is saturated with calcite and dolomite, but unsaturated with gypsum and halite. The degree of salinity increases in the direction of the groundwater flow due to increased rock-water interaction.  相似文献   

Effect of traditional management practices on woody species composition and structure in montane subtropical forests of Meghalaya,Northeast India     

Aabid Hussain Mir  Krishna Upadhaya 《山地科学学报》2017,14(8):1500-1512

In Meghalaya, northeast India, the local people have the tradition of managing forest resources since early ages. The management practice varies and there are forests with high degree of protection, where no extraction (sacred forests) is allowed. There are also forests with moderate- level of protection and -extraction (reserved forests) as well as forests with low level of protection and open extraction (village forests). The present study was conducted to understand the impact of this traditional management system on the level of human disturbance, and on community composition and structure of the forests in Khasi hills of Meghalaya. The result revealed that disturbance index was low, whereas species richness, density and basal cover were significantly high in forests with high degree of protection (sacred forest) than those with low protection (reserved and village forest). Majority of endemic and threatened plant species were restricted to sacred forests as compared to the other forest types. Though these practices have ensured the sustainable use of forest resources by the local people but due to increased human- pressure and -disturbances, more effective conservation strategies need to be undertaken. Therefore, providing alternatives for fuel Received: 28 July 2016 Revised: 1 October 2016 Accepted: 15 December 2016 wood to local people, environmental education, encouraging afforestation and developmental activities involving local communities are recommended.  相似文献   

High-resolution X-ray fluorescence profiling of hybrid event beds: Implications for sediment gravity flow behaviour and deposit structure     

Arif Hussain  Peter D. W. Haughton  Patrick M. Shannon  Jonathan N. Turner  Colm S. Pierce  Arnau Obradors-Latre  Simon P. Barker  Ole J. Martinsen 《Sedimentology》2020,67(6):2850-2882

Hybrid event beds form when turbidity currents that transport or locally acquire significant quantities of mud decelerate. The mud dampens turbulence driving flow transformations, allowing both mud and sand to settle into dense, near-bed fluid layers and debris flows. Quantifying details of the mud distribution vertically in what are often complex tiered deposits is critical to reconstructing flow processes and explaining the diverse bed types left by mud-bearing gravity flows. High-resolution X-ray fluorescence core scanning provides continuous vertical compositional profiles that can help to constrain mud distribution at sub-millimetre scale, offering a significant improvement over discrete sampling. The approach is applied here to cores acquired from the Pennsylvanian Ross Sandstone Formation, western Ireland, where a range of hybrid event beds have been identified. Raw X-ray fluorescence counts are calibrated against element concentrations and mineral abundances determined on coincident core plugs, with element and element log-ratios used as proxies to track vertical changes in abundances of quartz, illite (including mica), chlorite and calcite cement. New insights include ‘stepped’ (to higher values) as opposed to ‘saw-tooth’ vertical changes in mud content and the presence of compositional banding that would otherwise be overlooked. Hybrid event beds in basin floor sheets that arrived ahead of the prograding fan system have significantly cleaner sandy components than those in mid-fan lobes. The latter may imply that the heads of the currents emerging from mid-fan channels entrained significant mud immediately before they collapsed. Many of the H3 debrites are bipartite with a sandier H3a division attributed to re-entrainment and mixing of a trailing debris or fluid mud flow (H3b) with sand left by the forward part of the flow. Hybrid event bed structure may thus partly reflect substrate interaction and mixing during deposition, and the texture of the bed divisions may not simply mirror those in the suspensions from which they formed.  相似文献   

腾格里沙漠盐湖氯同位素地球化学特征     

韩凤清  毛庆飞  马茹莹  张燕霞  孙宇强  韩继龙  年秀清  刘文玉  SYED Asim Hussain  马喆 《湖泊科学》2018,30(4):1152-1160

δ~(37)Cl值可以用来指示盐湖演化过程中卤水的蒸发浓缩程度、可能的补给来源和控制因素,本文对腾格里沙漠地区12个代表性盐湖卤水样品开展了氯同位素组成研究.结果表明,研究区内沙漠盐湖卤水的δ~(37)Cl值变化范围为-0.10‰~1.36‰,平均值为0.55‰;其中,硫酸钠亚型卤水的δ~(37)Cl值范围为-0.10‰~1.36‰(平均值为0.56‰),硫酸镁亚型卤水的δ~(37)Cl值范围为0.14‰~0.82‰(平均值为0.48‰).对比柴达木盆地现代盐湖分析数据,发现区内沙漠盐湖的δ~(37)Cl平均值明显大于柴达木盆地盐湖的δ~(37)Cl平均值,并且,硫酸钠亚型卤水δ~(37)Cl最高,硫酸镁亚型卤水次之,氯化物型卤水最小.基于不同盐湖地下水咸化程度以及盐湖卤水中δ~(37)Cl值与Br/Cl系数关系的研究,揭示了研究区东部和东北部盐湖可能受到第三系地层咸水的补给,而其他盐湖主要受蒸发浓缩作用影响.δ~(37)Cl值分布特征则显示,腾格里沙漠地区部分盐湖在形成过程中可能受到区域构造活动诱发的第三系深部水补给及水-岩作用等多重因素的影响.  相似文献   

Remote sensing-based geostatistical hot spot analysis of Urban Heat Islands in Dhaka,Bangladesh     

Nur Hussain  S.M. Shahriar Ahmed  Amena Muzaffar Shumi 《Singapore journal of tropical geography》2023,44(3):438-458

Urban Heat Island (UHI) refers to a phenomenon whereby urban areas experience higher temperatures compared to the surrounding areas. Remote sensing-based Land Surface Temperature (LST) measurements can be utilized to measure UHI. This study emphasized on geostatistical remote sensing-based hot spot analysis ($G_i^{*}$) of UHI in Dhaka, Bangladesh as a way of examining the influences of Land Use Land Cover (LULC) on UHI from 1991 to 2015. Landsat 5 and 7 satellite-based remote sensing indices were used to explore LULC, UHI and environmental footprints during the study period. The Urban Compactness Ratio (C_oR) was used to calculate the urban form and augmented characteristics. The Surface Urban Heat Island (SUHI) intensity (ΔT) was also used to explore the effects of UHI on the surrounding marginal area. Based on our investigations into LULC, we discovered that around 71.34 per cent of water bodies and 71.82 percent of vegetation cover decreased from 1991 to 2015 in Dhaka city. Contrastingly, according to C_oR readings, 174.13 km² of urban areas expanded by 249.77 per cent. Our hot spot analysis also revealed that there was a 93.73 per cent increase in hot concentration zones. Furthermore, the average temperature of the study area had increased by 3.26°C. We hope that the methods and results of this study can contribute to further research on urban climate.  相似文献   

Full-scale experimental investigations on the response of a flooded passenger vehicle under subcritical conditions     

Al-Qadami  Ebrahim Hamid Hussein  Mustaffa  Zahiraniza  Shah  Syed Muzzamil Hussain  Matínez-Gomariz  Eduardo  Yusof  Khamaruzaman Wan 《Natural Hazards》2022,110(1):325-348

Natural Hazards - Vehicles can be easily swept away by floodwaters once the flow velocity and depth reach certain critical limits, with probabilities toward fatality reported to be nearly 50%....  相似文献