首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9篇
  免费   0篇
大气科学   1篇
地质学   6篇
综合类   2篇
  2022年   1篇
  2021年   2篇
  2019年   2篇
  2018年   2篇
  2013年   1篇
  2009年   1篇
排序方式: 共有9条查询结果,搜索用时 453 毫秒
1
1.
The seasonal abundance of flagellates has been monitored over a period of 1 year from December2013 to November 2014(divided into 4 conjugative seasons namely winter, spring, summer, and autumn) in an experimental pond located in Rajshahi City Corporation area, Bangladesh. To our knowledge, this study is the first to shed light on the occurrence and possible interrelationships among heterotrophic flagellates(HF),bacteria and zooplankton in Bangladesh and the result obtained by this study will be beneficial for similar water ecosystem all over the world. Standard methods were used to determine the prescribed hydrological parameters and zooplankton cell density. Maximum HF abundance(14 346.00 cells/mL) was found in the spring and the minimum(5 215.00 cells/mL) occurred in the summer. Inverse to HF, significantly(P0.05)higher zooplankton abundance was found during the winter(782.00±47.62 cells/mL) and the lowest value was found in the autumn(448.00±39.15 cells/mL). Whereas similar to the HF, total bacterial abundance was significantly higher during the spring((2.25±1.05)×10~5 cells/mL) and lower in the summer((0.79±0.06)×105 cells/mL). Multivariate analyses(ANOSIM and MDS) have shown significant seasonal differences for cell numbers where MDS ordination plot and cluster analysis based on similarity in the genera abundance of HF revealed overlapping condition between winter and spring. Canonical correspondence analysis(CCA) also showed a distinct separation among the genera based on the prevailing hydrological situation and indicated that temperature, pH, BOD_5, and NO_3~- were the most important environmental variables in determining the observed variation in HF community structure. Among the biological factors, zooplankton showed negative but total bacteria were positively correlated with HF abundance.  相似文献   
2.
Participation of local people during any disaster is enormous. They possess better knowledge and information about their own community than anyone else from the outside. This study proposes Participatory Vulnerability Reduction (PVR), a community-based approach for disaster management. The concept of PVR was applied to an urban community of Dhaka city (Ward no. 06 of Dhaka North City Corporation) which has been identified by the Comprehensive Disaster Management Programme as one of the most vulnerable areas of the city for earthquake. PVR consists three steps, and in each step, different participatory urban appraisal tools were used. In the first step, the community people assessed the earthquake vulnerability. It was found that some certain parts of the study area are highly vulnerable due to lack of accessibility to the critical facilities, inadequacy of open space, poor construction practice and unsuitable soil condition for building construction. This was followed by analyzing the root causes and effects of these problems. Structural fragility of the buildings, construction of settlements by filling the low-lying areas and development of slums beside taller buildings are the three major causes behind the above vulnerable issues. In the second step, capacity of the community was assessed in terms of resources and their organizational structure. In the final step, local people developed the strategies to overcome the vulnerability and a community-based organizational set up was proposed to coordinate the collective actions. Although developed in local context, application of PVR is not limited for earthquake and it can be replicated for other communities as well.  相似文献   
3.
Natural Hazards - The occurrence of heavy rainfall in the south-eastern hilly region of Bangladesh makes this area highly susceptible to recurrent flash flooding. As the region is the commercial...  相似文献   
4.
Policy initiatives in India, such as the Social Forestry Program and later the Joint Forest Management, were introduced for their co-benefits, including forest protection, employment opportunities, and added income for communities living in and around the forests. The evolution of these forest policies is critically reviewed. It is argued that India is perfectly positioned to benefit from climate change mitigation efforts, due to a rich, albeit chequered, history in forest management. National forestry policies are examined to assess how they can complement international climate change mitigation instruments, such as the Clean Development Mechanism (CDM) and the more recent Reduced Emissions from Deforestation and Forest Degradation (REDD or REDD+ with conservation, sustainable management of forests, and enhancement of forest carbon stocks) and aid national sustainable development objectives. There is a need to heed the experiences from India's evolving forest policies, particularly those concerning land tenure and resource rights, which lack specificity within international mechanisms. The active engagement of rural communities must be integral to any programmes that make any claim to development and to environmental integrity as a whole.

Policy relevance

India's forestry programmes are examined for their effectiveness in informing international initiatives such as the CDM and REDD+. Forestry policies in India can evolve to complement international climate mitigation tools. By examining current and historical forest legislation, and their subsequent impacts, it is shown how communities can sustain their system of forest management and retain/obtain rights to land and resources under the CDM and REDD+. Looking for such synergies within existing national policies to implement newer international initiatives can greatly facilitate and increase the momentum of global environmental change.  相似文献   
5.
The scientific borehole Baden-Sooss penetrates a succession of Badenian (Langhian, Middle Miocene) sediments at the type locality of the Badenian, the old brickyard Baden-Sooss in the Vienna Basin. The sedimentary succession of the 102-m-cored interval consists of more than 95% bioturbated, medium-to-dark gray marly shales with carbonate contents between 11 and 25% and organic carbon contents between 0.35 and 0.65%. Biostratigraphic investigations on foraminifera (mainly lower part of Upper Lagenid Zone) and calcareous nannoplankton (standard zone NN5) indicate an early Badenian (Langhian) age. Cycles in carbonate content, organic carbon content, and magnetic susceptibility have been identified by power spectra analysis. Correlations between the three variables are extremely significant. Using cross-correlation, periods around 40 m correlate significantly with the 100 kyr−1 eccentricity cycle, the ∼20 m periods with the obliquity cycle, and the 15 to 11-m periods with both precession cycles. Wavelet transformation and decomposition of composite periodic functions were used to obtain the position of the cycle peaks in the profile. Cross-correlation with orbital cycles (La2004) dates the Baden-Sooss core between −14.379 ± 1 and −14.142 my ± 9 kyr.  相似文献   
6.

Bangladesh is one of the topmost climate vulnerable countries in the world where the riverine island (char) dwellers are the most victims of climate change. Climate finance is perceived as the key instruments to address the issues related to climate change impacts and improve the livelihood resilience of the rural people. This article examines the role of climate finance governance at the vulnerable hazard-prone chars in Bangladesh. Climate finance adaptation governance has been assessed through measuring the climate service intervention, behavioral changes and impacts at the local level. The study reveals that the mechanism of climate finance in Bangladesh is good enough, but implementation is not satisfactory. It also observed that there is a lack of participatory governance for disaster management, and there is no direct contribution of climate finance governance in the village level which causes to fail the existing implementation strategy. The study suggests that a riverine island-based long-term development program should be implemented through ensuring effective monitoring system so that climate finance governance can contribute a lot and improve the food security and livelihood resilience of char dwellers.

  相似文献   
7.
Paleo-Mesoproterozoic (1.0-2.4 Ga) north Singhbhum mobile belt (NSMB) is one of the prominent polymetallic mineral belt within the Singhbhum crustal province of eastern India lying between Chotanagpur gneissic complex (CGC) in the north and the Archaean Singhbhum craton (>2.4 Ga) in the south. The study area is located along the northern fringe of Dalma volcano-sedimentary basin. Lithological variations, structure, metamorphism and tectonic setting indicate good prospect for regional gold exploration within this area.Extensive work by Geological Survey of India (GSI) within this basin reveals gold occurrences with its concentrations ranging from 0.1 to 4 ppm within the carbonaceous cherty quartzite. Gold mineralization within the area has been reported to be associated with quartz ± quartz carbonate vein either as disseminated gold or as refractory gold within the sulfides. A detailed study on the occurrence of refractory gold associated with carbonaceous cherty quartzite has not been carried out by any of the previous workers. The present work report the occurrence of refractory gold associated with sulfides within the carbonaceous host rocks. Detailed petrographic studies of the carbonaceous host rock reveal the presence of sulfides such as pyrrhotite, pyrite, chalcopyrite, arsenopyrite. EPMA studies of the host rocks indicate the presence of invisible gold within the sulfides varying in concentration from 100 to 1000 ppm. Total organic carbon (TOC), high resolution X-ray diffraction (HR-XRD) and Fourier transform infrared spectrometry (FTIR) analysis show the presence of organic carbon within the samples. Presence of organic carbon facilitates reducing environment required for gold mineralization within carbonaceous host rock in the study area.  相似文献   
8.
9.
GeoJournal - The research has been conducted to explore the extent of adopting mechanization at farm level and its impact on rice producers’ technical efficiency. Primary data and information...  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号