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C.M. Menzel 《Scientia Horticulturae》1985,25(1):31-48
Lychee (Litchi chinensis Sonn.) can be successfully propagated by several methods. The methods vary with respect to the uniformity and size of the new plants, the quality of the root system produced, time to bear, multiplication rate, destruction of parent tree, cost, labour requirements and the need for special techniques and equipment. Seedlings appear suitable for selection of new cultivars (and rootstocks), cuttings for rapid multiplication of new cultivars, marcottage and stooling for commercial multiplication of established cultivars and grafting for top-working new cultivars onto mature trees and/or onto improved rootstocks. Information is required on the comparative field performance of lychee propagated by these different techniques. 相似文献
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Book Review: Road Ecology: Science and Solutions 总被引：2，自引：0，他引：2
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As a human basement membrane-derived inhibitor of angiogenesis and tumor growth, canstatin has been paid great attention since it was isolated and identified in 2000. Canstatin significantly inhibited human endothelial cell migration and proliferation and induced apoptosis, suggesting that it might be a powerful and potential therapeutic molecule for atherosclerosis, unstable angina and tumor. 相似文献
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利用温室,可以人为地创造有利于葡萄扦插育苗的综合条件,且节省土地和劳动力,管理方便,成活率高,提早进入结果期. 相似文献
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Agent-based land-use models: a review of applications 总被引：9，自引：0，他引：9
Robin B. Matthews Nigel G. Gilbert Alan Roach J. Gary Polhill Nick M. Gotts 《Landscape Ecology》2007,22(10):1447-1459
Agent-based modelling is an approach that has been receiving attention by the land use modelling community in recent years,
mainly because it offers a way of incorporating the influence of human decision-making on land use in a mechanistic, formal,
and spatially explicit way, taking into account social interaction, adaptation, and decision-making at different levels. Specific
advantages of agent-based models include their ability to model individual decision-making entities and their interactions,
to incorporate social processes and non-monetary influences on decision-making, and to dynamically link social and environmental
processes. A number of such models are now beginning to appear—it is timely, therefore, to review the uses to which agent-based
land use models have been put so far, and to discuss some of the relevant lessons learnt, also drawing on those from other
areas of simulation modelling, in relation to future applications. In this paper, we review applications of agent-based land
use models under the headings of (a) policy analysis and planning, (b) participatory modelling, (c) explaining spatial patterns
of land use or settlement, (d) testing social science concepts and (e) explaining land use functions. The greatest use of
such models so far has been by the research community as tools for organising knowledge from empirical studies, and for exploring
theoretical aspects of particular systems. However, there is a need to demonstrate that such models are able to solve problems
in the real world better than traditional modelling approaches. It is concluded that in terms of decision support, agent-based
land-use models are probably more useful as research tools to develop an underlying knowledge base which can then be developed
together with end-users into simple rules-of-thumb, rather than as operational decision support tools.
This paper arises from research conducted as part of the UK Research Councils’ RELU Programme (award number RES-224-25-0102).
RELU is funded jointly by the Economic and Social Research Council, the Biotechnology and Biological Sciences Research Council
and the Natural Environment Research Council, with additional funding from the Department for Environment, Food and Rural
Affairs and the Scottish Executive Environment and Rural Affairs Department. 相似文献
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Sensory evaluations of 2 cultivars of cantaloupe (Cucumis melo var. reticulatus) at the eating-ripeness stage indicated considerable variations in quality. Soluble solids, flesh firmness, rind resistance and volatile flavor components also varied. Mechanical devices for testing tissue texture correlated well with sensory evaluations. There was low correlation between total volatiles determined by gas chromatography and aroma. However, differences were noted in the production of volatile compounds between melons. Statistical analysis of the data indicated low correlation between eating-quality and soluble solids content. Sweetness was the most important attribute in the determination of eating-quality. 相似文献
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Jari Lyytimäki 《Urban Forestry & Urban Greening》2014,13(3):418-424
Public perceptions and expectations towards ecosystems are an important part of environmental management and planning. This article focuses on the media representations that disseminate information, create framings and influence public attitudes. More specifically, the focus is on print media representations of ecosystem disservices. Ecosystem disservices are functions or properties of ecosystems that cause negative effects on human well-being or that are perceived as harmful, unpleasant or unwanted. Results from a case study focusing on the Finnish newspaper coverage of ecosystem disservices are presented. The results show that a wide variety of harms and nuisances related to ecosystems are brought up and discussed by the media. Implications for environmental management are discussed. The key claim is that taking into account the full repertoire of media representations of ecosystem functions is vital for preventing, anticipating and solving controversies related to environmental management and planning. 相似文献
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Lacunarity analysis of spatial pattern: A comparison 总被引：6，自引：0，他引：6
Lacunarity analysis has been proposed as a general method for the analysis of spatial pattern, in particular for patterns of the dispersion of points. The method is clearly an improvement over the variance:mean ratio approach based on quadrat counts, because it examines dispersion at a range of spatial scales. This paper examines the properties of lacunarity analysis and compares it with other methods of pattern analysis. Lacunarity analysis gives different results for complementary patterns, which may be an advantage depending on circumstances. The method, however, is not precise in determining the scale or the patch size in pattern with known properties. A modification that improves the interpretability of the results of the analysis is introduced but a weakness of this approach is that it does provide clear indications of the characteristics of cases that exhibit more than one scale of pattern. Because different methods react to different features in data, it is recommended that data be analysed by more than one method and the results compared for greater insight into their characteristics. 相似文献
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Management of urban recreational woodlands: The case of Norway 总被引：1，自引：0，他引：1
Vegard Gundersen Lars Helge Frivold Tor Myking Bernt-Hvard
yen 《Urban Forestry & Urban Greening》2006,5(2):73-82
A questionnaire was mailed to 351 forest supervisors in Norway about the condition and management of urban woodlands important for recreation. The overall respondense rate was 56% and included 29 large urban settlements (10,000 inhabitants) and 168 small urban settlements (200–9999 inhabitants), encompassing about 37% of the Norwegian population. The areas included in the survey cover 194,100 ha, i.e. 1.6% of the forested area. Urban woodlands were defined as the annually most frequently visited forest areas larger than 50 ha. The average size of urban woodlands was about 1000 ha, equal in large and small urban settlements. About 73% of the urban woodlands were closer than 500 m from settlements. The mean proportion of forest in the urban fringe was 40%. Like most forested land in Norway, urban woodlands were mainly privately owned. In large urban settlements the proportion of municipal forest was slightly higher than in small urban settlements. The distributions of forest stand age and tree species composition in urban woodlands did not deviate from the overall forest situation in the region. Silviculture and forest plans were prominent in urban woodlands around both large and small urban settlements, but special plans for recreation and conservation were equally rare. Recreational facilities and conflicts were most common in urban woodlands around large urban settlements. The effect of the recommendations on management of urban woodlands developed during the 1970s is questioned regarding the small differences between urban woodlands and the general forest situation, as well as between woodlands of large and small urban settlements. However, recreational efforts may have been more intensive in smaller neighbourhood woodlands of less than 50 ha, which were beyond the scope of this survey. 相似文献
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Recreation use of urban forests: An inter-area comparison 总被引：5，自引：0，他引：5
Recreation use in two urban forests in Vienna, Austria was compared. Visitors to an inner-urban forest and to a peri-urban forest were monitored by means of video observation during 1 year, from dawn to dusk. The amount of use and the temporal use pattern of the main user types, identified by video interpreters as walkers, cyclists, dog walkers and joggers, were compared. In the inner-urban forest, surrounding settlements, schools and business areas evoked high-use pressure, commuting activities, high shares of all-day activities, more morning and evening use particularly on workdays and, overall, more workday use. The peri-urban forest was, by far, not so heavily used and the proportion of daily routine activities such as dog walking and jogging was reduced because of the lower population density in the surroundings. While the potential for user conflicts in the inner-urban forest seemed to be quite high at weekends and workday late afternoons and evenings, in the peri-urban forest this potential was only high during weekend afternoons in the warmer season, due to the temporally concentrated appearance of walkers and bicyclists. 相似文献
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