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51.
Formal models for service composition have been proposed with the variation of the requirements of service developers. Some
famous models have provided checking and verification techniques and tools for the behavior of service composition. These
models generally focus much on the message flow of web services and neglecting the data contained in the exchanged messages
among services, which restrict the application range of these models and also the web service techniques. As new kind of services
with different protocols and communication methods have appeared, it is needed to model service composition from a new view
which is adapted to the new development in service area. In this paper we offer a function oriented model of service composition
which treats the composite service as a software system and specify the function of services which can be directly used to
the realization by service providers. 相似文献
52.
The author articulates key stressors in the lives of families who are homeless. These stresses often combine with barriers such as lack of job opportunities and/or insensitive professionals. Strategies for helping homeless families overcome these barriers and related issues are presented. 相似文献
53.
Pigeons' keypecking was reinforced by food on baseline schedules of multiple variable interval (VI) x VI x and on contrast schedules of multiple VI x VI y. Deprivation of food was varied by maintaining subjects at 75%, 85%, and 95% (+/- 2%) of their free-feeding weights. Positive and negative behavioral contrast were observed. The size of the contrast was not systematically altered by changes in deprivation. Positive and negative contrast were both larger later in the session than they were earlier. Within-session decreases in responding were steeper for the baseline than for the contrast schedules for positive contrast. Within-session decreases were steeper for the contrast than for the baseline schedules for negative contrast. These results were predicted by the idea that different amounts of habituation to the reinforcer during the baseline and contrast schedules contribute to behavioral contrast. The results show that contrast occurs under conditions that reduce the effect of the following component. The results support the assumption that positive and negative contrast are produced by symmetrical theoretical variables. 相似文献
54.
In five conditioned taste aversion experiments with rats, summation, retardation, and preference tests were used to assess the effects of extinguishing a conditioned saccharin aversion for three or nine trials. In Experiment 1, a summation test showed that saccharin aversion extinguished over nine trials reduced the aversion to a merely conditioned flavor (vinegar), whereas three saccharin extinction trials did not subsequently influence the vinegar aversion. Experiment 2 clarified that result, with unpaired controls equated on flavor exposure prior to testing; the results with those controls suggested that the flavor extinguished for nine trials produced generalization decrement during testing. In Experiment 3, the saccharin aversion reconditioned slowly after nine extinction trials, but not after three. Those results suggested the development of latent inhibition after more than three extinction trials. Preference tests comparing saccharin consumption with a concurrently available fluid (water in Experiment 4, saline in Experiment 5) showed that the preference for saccharin was greater after nine extinction trials than after three. However, saccharin preference after nine extinction trials was not greater, as compared with that for either latent inhibition controls (Experiments 4 and 5) or a control given equated exposures to saccharin and trained to drink saline at a high rate prior to testing (Experiment 5). Concerns about whether conditioned inhibition has been demonstrated in any flavor aversion procedure are discussed. Our findings help explain both successes and failures in demonstrating postextinction conditioned response recovery effects reported in the conditioned taste aversion literature, and they can be explained using a memory interference account. 相似文献
55.
Björn Wittrock 《Higher Education》1984,13(2):121-138
The Leverhulme programme of study into the future of higher education is an impressive analytical effort carried through with expediency and allowing for wide participation. However, the programme is not only an ambitious exercise in policy analysis and unorthodox planning. It also involves processes of bargaining and policy advocacy. But the demands of these different roles have not been openly examined. Thus the programme has unnecessarily rendered itself open to criticism. In particular, many of the recommendations echo a consistent plea for new institutional arrangements for central co-ordination and top-down management and control. These recommendations, however, have received little or no underpinning and are actually at odds with some of the most qualified studies of the Leverhulme programme itself. Furthermore, the programme has tended to neglect two of the most urgent tasks of policy analysis, namely to outline a range of available options - rather than to produce a broad consensus view - and to clearly spell out major value tradeoffs involved - rather than to assure that there are no significant drawbacks attached to the options being advocated.Prepared when the author was a Visiting Scholar of the Comparative Higher Education Research Group, University of California, Los Angeles. The author is indebted to the Director of the Group, Professor Burton Clark, for incisive comments on some of the issues raised by the Leverhulme Programme and to Dr. Gary Rhoades of the same Group for helpful comments on a previous draft of the article. 相似文献
56.
师生冲突的概念界定与分类探究——基于刘易斯·科塞的冲突分类理论 总被引:15,自引:0,他引:15
论文通过借鉴和辨析社会学理论中的冲突概念,对师生冲突概念作出界定。根据美国当代社会学家刘易斯·科塞的冲突分类理论,对学校师生冲突进行分类研究。在此基础上提出了三个观点:学校师生冲突的多数属于非现实性冲突;师生结构由紧密走向松散是师生冲突增多的重要原因;师生冲突具有一定的正面功能。 相似文献
57.
石敏俊 《浙江大学学报(A卷英文版)》2004,5(12):1533-1542
Land degradation is one of the severe environmental problems in China. In order to combat land degradation, a soil conservation program was introduced since 2000 to reduce soil erosion by converting slope-cultivated land into forestry and pasture. This paper represents the first systematic attempt to investigate the impact of the soil conservation program on land degradation in the loess plateau. The results indicate that the soil conservation program to convert slope fields into forest or pasture is an effective way to combat soil erosion. However, a subsidy that is higher than profit of land use activity of slope fields before their conversion into forest and pasture is needed to encourage farmers to join the conservation program. A policy measure to encourage and assist farmers to develop sedentary livestock by using crops produced from fields as well as fodder and forage grass from the converted slope fields might contribute to combat soil erosion. Increase in off-farm job opportunities may encourage households to reduce cultivation in slope fields. That implies a policy measure to encourage rural urbanization might contribute to combat soil erosion. 相似文献
58.
59.
Yangxueqingnao particles inhibit rat vascular smooth muscle cell proliferation induced by lysophosphatidic acid 总被引:1,自引:0,他引:1
Cai W Xu Y Chen JZ Huang SR Lu ZY Wang ZK 《Journal of Zhejiang University. Science. B》2005,6(9):892-896
Objective: To observe the effect of Yangxueqingnao particles on rat vascular smooth muscle cell (VSMC) proliferation induced by lysophosphatidic acid (LPA). Methods: The amount of3H-TdR (3H-thymidine) admixed in cultured rat VSMC was measured and mitogen-activated protein kinase (MAPK) activity and lipid peroxidation end product malondialdehyde (MDA)content of the VSMC were assayed. Results: 1×10-9, 1×10-8, 1×10-7 mol/L LPA in a concentration dependent manner, induced the amount of 3H-TdR admixed, MAP kinase activity, and MDA content of the cultured rat VSMC to increase. However, 5%, 10%,and 15% Yangxueqingnao serum preincubation resulted in a decrease of 23.0%, 42.0%, and 52.0% (P<0.01) respectively in the amount of 3H-TdR admixed, a decline in VSMC MAP kinase activity of 13.9% (P<0.05), 29.6% (P<0.01), and 48.9% (P<0.01)respectively, and also, a decrease in MDA content of VSMC of 19.4%, 24.7%, and 43.2% (P<0.01) respectively, in the 1×10-7mol/L LPA-treated VSMC. Conclusions: LPA activates the proliferation and lipid peroxidation of VSMC in a concentration dependent manner. The LPA-induced VSMC proliferation is related to the activity of MAP kinases, enzymes involved in an intracellular signalling pathway. The results of the present study showed that Yangxueqingnao particles can effectively inhibit LPA-induced VSMC proliferation, MAP kinase activation, and reduce lipid peroxidative lesion. 相似文献
60.
This investigation analyzed goals from the Individual Educational Programs (IEPs) of 54 high school students with diagnosed
reading disabilities in basic skills (decoding and/or word identification). Results showed that for 73% of the students, the
IEPs written when they were in high school failed to specify any objectives regarding their acute difficulties with basic
skills. IEPs from earlier points in the students’ educations were also reviewed, as available. For 23 of the students, IEPs
were present in the students’ files for three time points: elementary school (ES), middle school (MS), and high school (HS).
Another 20 students from the sample of 54 had IEPs available for two time points (HS and either MS or ES). Comparisons with
the IEPs from younger years showed a pattern of decline from ES to MS to HS in the percentage of IEPs that commented on or
set goals pertaining to weaknesses in decoding. These findings suggest that basic skills deficits that persist into the upper
grade levels are not being sufficiently targeted for remediation, and help explain why older students frequently fail to resolve
their reading problems. 相似文献