988 resultados para English Resource Grammar


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For the improvement of genetic material suitable for on farm use under low-input conditions, participatory and formal plant breeding strategies are frequently presented as competing options. A common frame of reference to phrase mechanisms and purposes related to breeding strategies will facilitate clearer descriptions of similarities and differences between participatory plant breeding and formal plant breeding. In this paper an attempt is made to develop such a common framework by means of a statistically inspired language that acknowledges the importance of both on farm trials and research centre trials as sources of information for on farm genetic improvement. Key concepts are the genetic correlation between environments, and the heterogeneity of phenotypic and genetic variance over environments. Classic selection response theory is taken as the starting point for the comparison of selection trials (on farm and research centre) with respect to the expected genetic improvement in a target environment (low-input farms). The variance-covariance parameters that form the input for selection response comparisons traditionally come from a mixed model fit to multi-environment trial data. In this paper we propose a recently developed class of mixed models, namely multiplicative mixed models, also called factor-analytic models, for modelling genetic variances and covariances (correlations). Mixed multiplicative models allow genetic variances and covariances to be dependent on quantitative descriptors of the environment, and confer a high flexibility in the choice of variance-covariance structure, without requiring the estimation of a prohibitively high number of parameters. As a result detailed considerations regarding selection response comparisons are facilitated. ne statistical machinery involved is illustrated on an example data set consisting of barley trials from the International Center for Agricultural Research in the Dry Areas (ICARDA). Analysis of the example data showed that participatory plant breeding and formal plant breeding are better interpreted as providing complementary rather than competing information.

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There is substantial economic potential for exploiting wildlife resources for non-consumptive wildlife-oriented recreation (NCWOR) tourism and this type of tourism if well managed, can result in the long-term conservation of wildlife resources. This is especially important in cases where wildlife resources are declining due to habitat destruction, poaching and other human threats, as is so for sea turtles. In this paper, relevant ecotourism literature outlining the economic values of NCWOR activities is reviewed to show that a significant potential exists for developing sea turtle-based tourism. Duffus and Dearden's (1990. Biological Conservation, 53, 213-231) conceptual framework for the development of wildlife tourism and its extension and application by Higham (1998. Tourism Management, 19 (6), 521-531) is analysed to see if it might be applied to sea turtle-based ecotourism in Australia at Mon Repos Conservation Park. Threats to sea turtle populations are growing especially as a result of human activities and these underline the importance of finding an economic rationale to conserve the remaining species. Economic benefits from turtle-based tourism can provide such a rationale. However, such tourism must be managed appropriately if it is to be sustained. Queensland Parks and Wildlife Service has adopted management strategies at Mon Repos Conservation Park with this in mind and these strategies are outlined. (C) 2001 Elsevier Science Ltd. All rights reserved.

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As the United States and Australia struggle with contemporary crises over competing uses of rapidly depleting natural resources, there are striking parallels between American Indian and Australian Aboriginal communities demanding a place at the management table and offering culturally based understandings of and solutions for the ecosystems at risk. These efforts to integrate indigenous knowledge into mainstream natural resource management are part of larger legal and political debates over land tenure, the locus of control, indigenous self-governance, and holistic ecosystems management.

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Given the importance of syllables in the development of reading, spelling, and phonological awareness, information is needed about how children syllabify spoken words. To what extent is syllabification affected by knowledge of spelling, to what extent by phonology, and which phonological factors are influential? In Experiment 1, six- and seven-year-old children did not show effects of spelling on oral syllabification, performing similarly on words such as habit and rabbit. Spelling influenced the syllabification of older children and adults, with the results suggesting that knowledge of spelling must be well entrenched before it begins to affect oral syllabification. Experiment 2 revealed influences of phonological factors on syllabification that were similar across age groups. Young children, like older children and adults, showed differences between words with short and long vowels (e.g., lemon vs. demon) and words with sonorant and obstruent intervocalic consonants (e.g., melon vs. wagon). (C) 2002 Elsevier Science (USA). All rights reserved.

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