The seasonally flooded wetlands are often neglected due to their ephemeral and erratic appearance and small size, however, their hydro-ecological importance, socio-economic values are equivalent to the permanent wetlands. Using dual-season Landsat multi-spectral imagery, this study highlights a comprehensive monitoring of the hydrological dynamics of wetlands in the lower reach of the Mayurakshi River at a 14-year temporal resolution with the seasonal mode of 1987–2014 time frames. Our results demonstrate the seasonal and periodic hydrological variability of water presence frequency (WPF) in six wetland complexes defined for this study. The Hijal, Ghambira and Maldah wetland complexes are highly affected by the change of WPF, while Dwarka complex is relatively stable. The assessment of WPF change analysis showed that the method is proficient in identifying stable and physically vulnerable wetland patches and absolute loss of wetland inundation frequency resulting from various anthropogenic causes like regulation of river, dry farming practices and other integrated developmental works. The outcome of our study provides a robust basis for the fundamental hydrological and ecological studies and helpful for the conservation and management of seasonally flooded wetland resources in the tropical monsoon climate. 相似文献
The Panchayati Raj Institution is a statutory body elected by the local people through a well defined democratic process with specific responsibilities and duties. It is the most appropriate institution from village to the district level. The role of Panchayats (local self governing institutions) is important in view of their proximity to the local community, universal coverage and enlisting people’s participation on an institutionalized basis. Panchayat and municipalities are local governing institutions in countries like India, have a constitutional mandate under the 73rd and 74th constitutional amendments Act. Apart from the proper implementation of different ongoing developmental programmes, the panchayat system has to play pivotal roles in respect of natural as well as man-made disaster management. In India, Particularly in West Bengal the village level Disaster Management Committee is headed by ward members of gram panchayat. The Panchayati Raj Institutions provide adequate space to the weaker section of the communities at its three levels, i.e. village, block and district. Good governance can be an instrumental feature in poverty reduction. This study was undertaken in cyclone affected areas in West Bengal to assess the role of panchayat in disaster management. The empirical study revealed that main role performed by the panchayat in respect of disaster was reconstruction of damaged houses, crop protection measures, livestock management, health and sanitation measures. Besides these broad aspects, the panchayats officials also organized health camp, involved in rescue operation, arranging temporary shelters and so on as disaster management operation. Total 60 gram panchayat officials and 150 villagers were selected randomly as respondents for the present investigation. The data were analysed into mean score, rank position and spearman correlation coefficient to achieve the objectives. The findings of the study indicated that significant differences were observed on the opinion of the villagers and officials on reconstruction of houses and health and sanitation measures. The roles performed by the local self-government in disaster management were very poor. There was absolutely lack of involvement of people’s representative. Therefore, adequate supports are suggested on these aspects from the representatives in association with higher authorities. 相似文献
We study the radiation properties of an accretion disc around a rotating black hole. We solve the hydrodynamic equations and calculate the transonic solutions of accretion disc in the presence of shocks. Then we use these solutions to generate the radiation spectrum in the presence of radiative heating and cooling processes. We present the effect of spin parameter of the black hole on the emitted radiation spectrum. In addition, attention has also been paid to the variation in energy spectral index with Kerr parameter and accretion rate. We find that spectral index becomes harder as the spin parameter changes from negative (accretion disc is counter-rotating with respect to the black hole spin) to a positive value. Finally, we compute and compare the spectral characteristics due to a free-fall flow and a transonic flow. We notice significant differences in high energy contributions from these two solutions. 相似文献
Spatial equity in urban facilities or service distribution is considered as a critical determinant of the quality of urbanization. Spatial equity simply means the presence of adequate facilities and equal proximity. Many initiatives have mostly focused on one type of facility, obviating the holistic understanding of the equity of distribution of all basic facilities in cities. Moreover, the perceptions of the citizens in the process of planning are hardly considered. In this paper, an integrated facility-satisfaction index is presented to evaluate the balance between the distribution of facilities and the level of residents' satisfaction derived from those facilities. This method has taken all possible urban facilities and categorized them as educational, health, financial, recreation, and others. The per capita facility availability is calculated by incorporating the spatial distribution of urban facilities, the service range of facilities, population distribution, and weight. The proper weights have been given by employing the analytical hierarchy process (AHP). The satisfaction index has been derived from the citizens’ perception of each facility, marked on a 5-point Likert scale during the field survey. The paired-sample t-test demonstrated that there is a significant difference between the facility availability and satisfaction index at the significance level of 0.05. The application of the method is demonstrated in fast urbanizing Barasat city, West Bengal, India. Based on the degree of facility-satisfaction differences or correspondences, the entire region has been categorized into four zones viz. satisfied people with favorable facility availability, unsatisfied people with poor facility availability, unsatisfied people with relatively high facility availability, and satisfied people with relatively low facility availability. The pattern has been validated by identifying spatial clusters and spatial outliers of facility availability and satisfaction using local Moran’s I. This approach can help a city to distribute the facilities to satisfy the citizens of all corners which will help to overcome the constant problems of policy decisions without adequate and reliable information about the actual demand of the residents.
Seasonal and sexual variations as well as the effect of dry feed supplement on total drinking water intake and its utilization were observed in mithun (Bosfrontalis) - a semi-wild animal found in North Eastern Hill Region (NEHR) of India. In a completely randomized design, twelve adult mithuns (B. frontalis) as per their sex and body weight were assigned in two different rearing systems (free grazing and free grazing with dry concentrate feed supplementation), and ten growing male mithuns as per their body weight assigned in two different levels of dry concentrate feed supplementation (1.o kg and 2.0 kg dry concentrate feeds on green forage based diet) and in two different seasons (summer and winter). It was observed that the environmental temperature had a significant effect on drinking water intake by mithuns. Drinking water consumption (per unit of body weight) was significantly (P 〈 0.05) higher in summer than in winter. Supplementation of concentrate feed on free grazing animals resulted in increase in water consumption. Total water consumption (drinking as well as performed water) was found to be 15.18 litres per 100 kg body weight by growing mithun. Feed dry matter and digestible nutrient intakes by growing mithun were observed to be increased with the increase of supplementation of dry concentrate feed. Roughage to concentrate ratio did not affect the nutrient digestibility. Mithun calves drank an average of 4.30 litres water for each kg of dry matter intake. Metabolic water was significantly (P〈0.01) increased with the increase of supplementation of concentrate feed whereas water turn over, which depends upon the body weight of the animals, did not differ significantly on offering of lower or higher level of dry feed. Faecal water loss of growing mithun was decreased with the increase in intake of concentrate feed and was estimated to be 33 - 46 % of total water intake. Excretion of water through faeces of mithun was about 3.8 % of body weight. It could, there 相似文献
In the present study, Remote Sensing Technique and GIS tools were used to prepare landslide susceptibility map of Shiv-khola watershed, one of the landslide prone part of Darjiling Himalaya, based on 9 landslide inducing parameters like lithology, slope gradient, slope aspect, slope curvature, drainage density, upslope contributing area, land use and land cover, road contributing area and settlement density applying Analytical Hierarchy Approach (AHA). In this approach, quantification of the factors was executed on priority basis by pair-wise comparison of the factors. Couple comparing matrix of the factors were being made with reasonable consistency for understanding relative dominance of the factors as well as for assigning weighted mean/prioritized factor rating value for each landslide triggering factors through arithmetic mean method using MATLAB Software. The factor maps/thematic data layers were generated with the help of SOI Topo-sheet, LIIS-III Satellite Image (IRS P6/Sensor-LISS-III, Path-107, Row-052, date-18/03/2010) by using Erdas Imagine 8.5, PCI Geomatica, Arc View and ARC GIS Software. Landslide frequency (%) for each class of all the thematic data layers was calculated to assign the class weight value/rank value. Then, weighted linear combination (WLC) model was implied to determine the landslide susceptibility coefficient value (LSCV or ??M??) integrating factors weight and assigned class weight on GIS platform. Greater the value of M, higher is the propensity of landslide susceptibility over the space. Then Shivkhola watershed was classified into seven landslide susceptibility zones and the result was verified by ground truth assessment of existing landslide location where the classification accuracy was 92.86 and overall Kappa statistics was 0.8919. 相似文献
Fluoride (F) contamination study had been carried out to see its allocation in Kurmapalli watershed, Nalgonda district, Andhra
Pradesh, India. The study area is located about 60 km SE of Hyderabad city. The groundwater is the main source of water for
their living. The groundwater in villages and its surrounding are affected by fluoride contamination and consequently the
majority of the people living in these villages has health hazards and is facing fluorosis. The purpose of this study is to
identify the wells with high F, raise awareness in people, study the water chemistry, and also find out the source of F in
groundwater. A total of 32 groundwater samples were collected from different wells in both shallow aquifers and deeper fractures
zones during October 2004. The chemical analysis of groundwater has been done. Fluoride values vary from 0.7 to 19.0 mg/l.
It is noted that the maximum value (19.0 mg/l) is one of the highest values found in groundwater in India and 78% of the total
samples show F concentrations that exceeds the permissible limit value (1.5 mg/l). The highest value of F is found at Madanapur
bore well which is located at central part of the watershed. The F value of this bore well was monitored from October 2004
to October 2006. During this period the F concentration varies from 17.8 to 21.0 mg/l with mean 19.3 mg/l. There is no correlation
of F with chemical parameters except calcium. The Ca has shown inverse proportional with F. Water–rock interaction studies
were also carried out to understand the behavior of F in groundwater at prominent F affected areas. Rock samples were collected
and analyzed, and found their enrichment of F. The anthropogenic possibility of F is almost negligible. The rocks of this
area are enriched in F from 460 to 1,706 mg/kg. It is indicated that the rock–water interaction is the main source of F in
groundwater. The highest values of F are found in middle part of the region and are related to the occurrence of fluoride
rich rocks and their chemical kinetic behavior with groundwater. 相似文献
A group of 36 coral islands is being scattered in the Arabian Sea off the western coast of India. On such islands, groundwater
is the only source of fresh water for the islanders. The demand for groundwater is increasing every year due to growing population
and urbanization. On the other side the peculiar hydrologic, geologic and geomorphic features restrict the availability of
groundwater. Thus a proper understanding of the groundwater condition is important in order to meet this increasing demand
and also to formulate future development and management strategies. Detailed hydrogeological, geophysical and hydrochemical
studies had been carried out to identify potential fresh groundwater resources and quantify vulnerable parts of Andrott Island,
Union Territory of Lakshadweep. Systematic collection and analysis of hydrological, geophysical and hydrochemical data gives
an early signal of deterioration in groundwater quality in the peripheral parts of eastern and western coasts of this island
and it suggests immediate measures for arresting the deterioration in groundwater quality as well as augmentation for restoration
of aquifer in some parts of the island. 相似文献
Zinc remediation of aqueous streams is of special concern due to its highly toxic and persistent nature. Conventional treatment technologies for the removal of zinc are not economical and further generate huge quantity of toxic chemical sludge. Biosorption is emerging as a potential alternative to the existing conventional technologies for the removal of metal ions from aqueous solutions. Mechanisms involved in the biosorption process include chemisorption, complexation, adsorption–complexation on surface and pores, ion exchange, microprecipitation, heavy metal hydroxide condensation onto the bio surface, and surface adsorption. Biosorption largely depends on parameters such as pH, the initial metal ion concentration, biomass concentration, presence of various competitive metal ions in solution, and to a limited extent on temperature. Biosorption using biomass such as agricultural wastes, industrial residues, municipal solid waste, biosolids, food processing waste, aquatic plants, animal wastes, etc., is regarded as a cost‐effective technique for the treatment of high volume and low concentration complex wastewaters containing zinc metal. Very few reviews are available where readers can get an overview of the sorption capacities of agro based biomasses used for zinc remediation together with the traditional remediation methods. The purpose of this review article is to provide the scattered available information on various aspects of utilization of the agro based biomasses for zinc metal ions removal. An extensive table summarizes the sorption capacities of various adsorbents. These biosorbents can be modified using various methods for better efficiency and multiple reuses to enhance their applicability at industrial scale. We have incorporated most of the valuable available literature on zinc removal from waste water using agro based biomasses in this review. 相似文献
Platinum group elements (PGE: Os, Ir, Ru, Rh, Pt, Pd) are important geochemical and cosmochemical tracers. Depending on physical
and chemical behaviour the PGEs are divided into two subgroups: IPGE (Ir, Os, Ru) and PPGE (Pd, Pt, Rh). Platinum group elements
show strong siderophile and chalcophile affinity. Base metal sulfides control the PGE budget of the Earth’s mantle. Mantle
xenoliths contain two types of sulfide populations: (1) enclosed within silicate minerals, and (2) interstitial to the silicate
minerals. In terms of PGE characters the included variety shows IPGE enriched patterns — similar to the melt-depleted mantle
harzburgite, whereas the interstitial variety shows PPGE enriched patterns — resembling the fractionated PGE patterns of the
basalt. These PGE characters of the mantle sulfides have been interpreted to be representative of multi-stages melting process
of the mantle that helped to shape the chemical evolution of the Earth. 相似文献