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1.
Matthias Schmidt 《山地科学学报》2005,2(2):91-104
Using political ecology as its conceptual framework, this paper focuses on the changes in forest utilisation and management of South Kyrgyzstan＇s walnut-fruit forests over the last century The aim of this study on human-environment interactions is to investigate the relationship between actors on the one side, their interests and demands, and the forests and forested lands on the other. Forest resource utilisation and management - and even the recognition of different forest products as resources - are connected with political and socioeconomic conditions that change with time. The walnut-fruit forests of South Kyrgyzstan are unique, characterised by high biodiversity and a multiplicity of usable products; and they have been utilised for a long time. Centralised and formal management of the forests started with the Russian occupation and was strengthened under Soviet rule, when the region became a part of the USSR. During this era, a state forest administration that was structured from Moscow all the way down to the local level drew up detailed plans and developed procedures for utilising the different forest products. Since the collapse of the Soviet Union, the socio-political and economic frame conditions have changed significantly, which has brought not only the sweeping changes in the managing institutions, but also the access rights and interests in the forest resources. At present, the region is suffering from a high unemployment rate, which has resulted in the forests＇ gaining considerable importance in the livelihood strategies of the local population. Political and economic liberalization, increased communication and transregional exchange relations have opened the door for international companies and agents interested in the valuable forest products. Today, walnut wood and burls, walnuts, wild apples and mushrooms are all exported to various countries in the world. Scientists and members of various international organisations stress the ecological value of the forests and are trying to establish nature conservation areas. Nevertheless, it is to fear that a multiplicity of interrelated factors - the present transformation and globalization processes, the appearance of new actors, the local population＇s insecure economic situation and the erosion of managing institutions - are all leading to an intensified and unregulated exploitation of the forests, resulting in their degradation. 相似文献
2.
Gas emission prediction and recovery in underground coal mines 总被引：2，自引：0，他引：2
Strata gas can be released and captured from non-active and active gas resources either from virgin or relaxed strata, both prior to and when mining activities take place. The high and irregular gas emissions associated with high production longwall mining have provided a need to optimise the methods used to predict these gas levels and the ventilation requirements for gas dilution. A forecast of gas emissions during development drivage and longwall mining indicated possible gas and ventilation problems requiring the introduction of various gas drainage techniques and in maintaining the necessary air quantities in ventilation systems to satisfy the statutory gas limitations for various coal production rates. Although there are sound principles used in world-recognised methods of gas emission prediction, a new approach developed from long-term practical experience in underground gassy coal mine practices and gas-rock mechanics studies appear most suitable for local conditions and mining systems in use. The Lunagas ‘Floorgas' and ‘Roofgas' geomechanical and gas emission models offer an effective solution to these problems. Both programs are the most advanced engineering, numerical tools available to calculate gas source contributions to total gassiness and improve the accuracy and quality of gas control, gas capture technologies and ventilation system design. 相似文献
3.
H.R. Williams J.C. Bridges R.M. Ambrosi M.-C. Perkinson J. Reed L. Peacocke N.P. Bannister S.D. Howe R.C. O'Brien A.C. Klein 《Planetary and Space Science》2011,59(13):1621-1631
There is enormous potential for more mobile planetary surface science. This is especially true in the case of Mars because the ability to cross challenge terrain, access areas of higher elevation, visit diverse geological features and perform long traverses of up to 200 km supports the search for past water and life. Vehicles capable of a ballistic ‘hop’ have been proposed on several occasions, but those proposals using in-situ acquired propellants are the most promising for significant planetary exploration. This paper considers a mission concept termed Mars Reconnaissance Lander using such a vehicle. We describe an approach where planetary science requirements that cannot be met by a conventional rover are used to derive vehicle and mission requirements.The performance of the hopper vehicle was assessed by adding estimates of gravity losses and mission mass constraints to recently developed methods. A baseline vehicle with a scientific payload of 16.5 kg and conservatively estimated sub-system masses is predicted to achieve a flight range of 0.97 km. Using a simple consideration of system reliability, the required cumulative range of 200 km could be achieved with a probability of around 80%. Such a range is sufficient to explore geologically diverse terrains. We therefore plot an illustrative traverse in Hypanis Valles/Xanthe Terra, which encounters crater wall sections, periglacial terrain, aqueous sedimentary deposits and a traverse up an ancient fluvial channel. Such a diversity of sites could not be considered with a conventional rover. The Mars Reconnaissance Lander mission and vehicle presents some very significant engineering challenges, but would represent a valuable complement to rovers, static landers and orbital observations. 相似文献
4.
淮北闸河矿区高岭岩特征及其利用途径 总被引：6，自引：0，他引：6
用差热、X射线衍射及红外光谱等方法,对淮北闸河矿区下石盒子组底部5#、6#煤层间一层高岭岩矿层进行了研究。结果表明:矿层平均厚3.8m,矿石几乎全部是由高岭石组成的单矿物岩,有益组分Al2O3含量一般在36%~39%;主要有害组分Fe2O3含量变化在0.78%~1.71%之间;TiO2含量多在0.4 9%~0.97%。为矿物组成纯净,有益组分含量高但有害组分亦较高的高岭岩。这种岩石是生产化工产品,以及煅烧高岭土的良好原料。 相似文献
5.
Western China includes 12 provincial divisions (the 7 provinces of Sichuan, Guizhou, Yunnan, Shaanxi, Gansu, Qinghai and; 5 autonomous regions of Tibet, Ningxia, Xinjiang, Inner Mongolia and Guangxi; and one city of Chongqing), which comprise 71.4% of the national land area, 28.5% of the national population and produce 17.5% of the national GDP in China. There are 17 countries that have riparian relationships with western China, most of which are water-short countries. All are listed by UN ESCAP as countries with potential water crisis. The co-operative development and coordinated management of international rivers in western China is an important step toward the implementation of the national Great Western Development program. Taking into account of the national strategy and object hierarchy, as well as the development demand of the western region, it is necessary to pursue the multi-disciplinary study of the equitable allocation, utilisation, and ecoenvironment protection of transboundary water resources in the region. Such efforts will undoubtedly provide scientific evidence and support for the decision-making of the environmental protection and ecological construction and management in the western regions, the enforcement of the sub-regional economic co-operation, mitigation of trans-boundary conflicts, and enhancing bio-diversity conservation. 相似文献
6.
Cleophas Lado 《Applied geography (Sevenoaks, England)》2004,24(4):281-302
This paper examines farmers’ ethnobotanical knowledge, innovation and rural change, and indicates one way in which indigenous technical knowledge complementing scientific knowledge may be documented for use by development planners and agencies. This paper firstly identifies plant species recognised as resources by farmers, and considers the value of these resources. Secondly, the paper documents and assesses the ethnobotanical knowledge associated with the utilisation of plant species, before turning to examine how plant resources are defined by use and culture. It also demonstrates that some components of ethnobotanical knowledge have potential for the sustainable development of plant species. The study shows that farmers have started to domesticate some of the ‘traditional’ plants, and new crops have been introduced associated with corresponding innovations in local agricultural systems. Since the farmers have a relatively strong tradition in natural resources conservation, this study suggests that it will be possible to introduce community-based gene banks linked to formal or government facilities. The paper demonstrates that it is important to combine and interweave ‘modern’ and indigenous knowledges to produce a more realistic and sensitive understanding and management of natural environmental resources for sustainable development. 相似文献
7.
Influence of Rock Mass Parameters on the Performance of a TBM in a Gneissic Formation (Varzo Tunnel) 总被引：4，自引：1，他引：4
Summary The paper analyses the influence of rock mass quality on the performance of a double shield TBM in the excavation of a tunnel in a gneiss formation which is characterized by high strength and low fracture intensity.As full observation of the rock conditions was prevented by the use of segmental lining, a geomechanical survey of the face was performed during maintenance downtime and the observed conditions were correlated with the machine performance parameters for that same day. A statistical analysis of the data shows that penetration rate correlates well with a slightly modified RMR index (in which the influence of the water conditions and joint orientation were discounted), but the most important factor is by far the partial rating of the RMR classification related to joint spacing only. However in tunnels characterized by greater variability in rock strength and joint conditions, it could be worthwhile using the complete RMR index.Given the toughness of the rock, failure of the cutter bearings and supports were a frequent occurrence during excavation. Owing to this factor the influence of rock quality on the rate of advance was found to be weak and the correlation more scattered.The results obtained for the Varzo tunnel were compared with those relative to other tunnels in granitic rocks and found to be in good agreement. However the relationships obtained should be considered valid only for this type of rock; machine behaviour could be found to be markedly different in other rock types, even where rock material strength and joint frequency are the same. 相似文献
8.
We investigated the impact of African elephants (Loxodonta africana) on the structure and composition of Acacia tortilis woodland in northern Gonarezhou National Park, southeast Zimbabwe. A. tortilis woodland was stratified into high, medium and low elephant utilisation categories based on evidence of elephant habitat use as determined through dung-count surveys in relation to distance of woodland patches from perennial and natural surface water sources. The following variables were recorded in each study plot: tree height, species name, number of species, plant damage, basal circumference and number of stems per plant. A total of 824 woody plants and 26 woody species were recorded from the sampled A. tortilis woodland patches. Mean tree densities, basal areas, tree heights and species diversity were lower in areas with medium and high elephant utilisation as compared to low elephant utilisation areas. Plants damaged by elephants increased with increasing elephant utilisation. The study findings suggest that A. tortilis woodland is gradually being transformed into an open woodland. We recommended that protected area management in arid and semi-arid areas should consider (i) formulating clear thresholds of potential concern to allow for the conservation of sensitive woodlands such as A. tortilis woodlands and (ii) establishing long-term vegetation monitoring programmes. 相似文献
9.
New Zealand's brief history of human habitation has led to widespread and often irreversible change in the biophysical environment. Most of the wetlands were drained and de-forestation led to major gully and channel erosions and high amounts of sediment yield in the estuarine and marine environments. The scale of land-based effects on marine species is indeterminable. The legislation for managing the land–sea interface is widely acknowledged as having fallen short of its full potential. After the 2008 general election the new government commenced review of this legislation while consideration was given to ‘unlocking New Zealand's energy potential’ as a key component to an export-led economic recovery. The government is promoting oil, gas and mineral exploration on land and at sea. The government is also enacting boundaries that extend continental shelf jurisdiction. These developments may lead to further progress on an integrated system that covers all aspects of marine management that began in 2000. In any case, New Zealanders face important decisions regarding the tradeoffs between further resource utilisation and environmental protection. This article contributes to the discussion on integrated management to maintain a balance between utilisation and protection and does not reflect the view of the Ministry of Fisheries. 相似文献
10.
《Marine Policy》2016
With the development of the ecosystem approach to fisheries, improving fishing selectivity has increasingly been put forward as an objective for management. The aim of this paper is to clarify the limits of fishing selectivity and its use in fisheries management. Fishing selectivity would be better apprehended if restricted to the catching process only, not to the utilisation that is made of the catch once onboard, which falls under catch utilisation. Confusion would be further limited if fishing selectivity is restricted to the fishing operation scale, while exploitation pattern, i.e. the distribution of fishing mortality at the population or community level, applies to larger scales. Fishing selectively is minimizing bycatch – catching primarily the fishing trip targets. Since the ecological consequences of maximising the target catch relative to bycatch remain unknown at integrated scales, fishing selectivity cannot be used as an objective in itself. However, its small scale, high manageability and good understanding make it a convenient instrument to reach management objectives at large scales. Selectivity can serve to manage what is extracted from the ecosystem and thus what can be used, and/or to manage what is left in the ecosystem and how fishing impacts it. Different factors affect fishing selectivity, catch utilisation and exploitation patterns, some of them are manageable and thus can be used to move towards these objectives. Management tools are diverse, but need to be integrated to meet large-scale objectives. The complexity of dealing with large scales incurs a need to develop the available knowledge on exploitation patterns and catch utilisation to be able to adequately manage and monitor progress toward selectivity-related objectives. 相似文献