1000 resultados para sigmoid response


Relevância:

20.00% 20.00%

Publicador:

Resumo:

This thesis reports on the development of a conceptual framework for product aesthetics. By adopting the theoretical perspective that products are a medium of communication between designers and consumers, the nature of consumer response and designer intent is explored. By integrating a range of disparate literature within a single coherent framework, the varieties of consumer response to product visual form are illustrated. To investigate the ways in which designers intend to evoke these responses, a qualitative research study was undertaken. This primarily involved interviews with industrial designers and consumer investigators. Analysis of these interviews led to the development of a conceptual framework for designer intent which both mirrors, and integrates with, that produced for consumer response. By representing processes beyond design that are influential in determining product form, a broader contextual framework is presented within which product aesthetics is situated. In concluding the thesis, applications for this framework are discussed and future research directions are proposed.

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: In the violaxanthin (V) cycle, V is de-epoxidized to zeaxanthin (Z) when strong light or light combined with other stressors lead to an overexcitation of photosystems. However, plants can also suffer stress in darkness and recent reports have shown that dehydration triggers V-de-epoxidation in the absence of light. In this study, we used the highly stress-tolerant brown alga Pelvetia canaliculata as a model organism, due to its lack of lutein and its non-photochemical quenching independent of the transthylakoidal-ΔpH, to study the triggering of the V-cycle in darkness induced by abiotic stressors. Results: We have shown that besides desiccation, other factors such as immersion, anoxia and high temperature also induced V-de-epoxidation in darkness. This process was reversible once the treatments had ceased (with the exception of heat, which caused lethal damage). Irrespective of the stressor applied, the resulting de-epoxidised xanthophylls correlated with a decrease in Fv/Fm, suggesting a common function in the down-regulation of photosynthetical efficiency. The implication of the redox-state of the plastoquinone-pool and of the differential activity of V-cycle enzymes on V-de-epoxidation in darkness was also examined. Current results suggest that both violaxanthin de-epoxidase (VDE) and zeaxanthin-epoxidase (ZE) have a basal constitutive activity even in darkness, being ZE inhibited under stress. This inhibition leads to Z accumulation. Conclusion: This study demonstrates that V-cycle activity is triggered by several abiotic stressors even when they occur in an absolute absence of light, leading to a decrease in Fv/Fm. This finding provides new insights into an understanding of the regulation mechanism of the V-cycle and of its ecophysiological roles.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

EXECUTIVE SUMMARY 1. DECADAL-SCALE CLIMATE EVENTS 1.1 Introduction 1.2 Basin-scale Patterns 1.3 Long Time Series in the North Pacific 1.4 Decadal Climate Variability in Ecological Regions of the North Pacific 1.5 Mechanisms 1.6 References 2. COHERENT REGIONAL RESPONSES 2.1 Introduction 2.2 Central North Pacific (CNP) 2.3 California Current System (CCS) 2.4 Gulf of Alaska (GOA) 2.5 Bering Sea and Aleutian Islands 2.6 Western North Pacific (WNP) 2.7 Coherence in Regional Responses to the 1998 Regime Shift 2.8 Climate Indicators for Detecting Regime Shifts 2.9 References 3. IMPLICATIONS FOR THE MANAGEMENT OF MARINE RESOURCES 3.1 Introduction 3.2 Response Time of Biota to Regime Shifts 3.3 Response Time of Management to Regime Shifts 3.4 Provision of Stock Assessment Advice 3.5 Decision Rules 3.6 References 4. SUGGESTED LITERATURE 4.1 Climate Regimes 4.2 Impacts on Lower Trophic Levels 4.3 Impacts on Fish and Higher Trophic Levels 4.4 Impacts on Ecosystems and Possible Mechanisms 4.5 Regimes and Fisheries Management APPENDIX 1: RECENT ECOSYSTEM CHANGES IN THE CENTRAL NORTH PACIFIC A1.1 Introduction A1.2 Physical Oceanography A1.3 Lower Trophic Levels A1.4 Invertebrates A1.5 Fishes A1.6 References APPENDIX 2: RECENT ECOSYSTEM CHANGES IN THE CALIFORNIA CURRENT SYSTEM A2.1 Introduction A2.2 Physical Oceanography A2.3 Lower Trophic Levels A2.4 Invertebrates A2.5 Fishes A2.6 References APPENDIX 3: RECENT ECOSYSTEM CHANGES IN THE GULF OF ALASKA A3.1 Introduction A3.2 Physical Oceanography A3.3 Lower Trophic Levels A3.4 Invertebrates A3.5 Fishes A3.6 Higher Trophic Levels A3.7 Coherence in Gulf of Alaska Fish A3.8 Combined Standardized Indices of Recruitment and Survival Rate A3.9 References APPENDIX 4: RECENT ECOSYSTEM CHANGES IN THE BERING SEA AND ALEUTIAN ISLANDS A4.1 Introduction A4.2 Bering Sea Environmental Variables and Physical Oceanography A4.3 Bering Sea Lower Trophic Levels A4.4 Bering Sea Invertebrates A4.5 Bering Sea Fishes A4.6 Bering Sea Higher Trophic Levels A4.7 Coherence in Bering Sea Fish Responses A4.8 Combined Standardized Indices of Bering Fish Recruitment and Survival Rate A4.9 Aleutian Islands A4.10 References APPENDIX 5: RECENT ECOSYSTEM CHANGES IN THE WESTERN NORTH PACIFIC A5.1 Introduction A5.2 Sea of Okhotsk A5.3 Tsushima Current Region and Kuroshio/Oyashio Current Region A5.4 Bohai Sea, Yellow Sea, and East China Sea A5.5 References (168 page document)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Feeding trial was conducted in static water to assess the growth of H. longifilis fingerlings fed different I inclusion levels of mucuna seed meal (MSM). Raw and boiled MSM were used in the diets at 10%, 20%, 30% and 40% inclusion levels and the performance of fish fed these diets was compared with fish fed a fishmeal-based diet which contained 40% protein. All diets were prepared to be isonitrogenous and isocaloric A two by five factorial experiment with three replicates using ten fish of average initial weight 1 .46g was carried out. Daily fish ration of five percent body weight was administered two times for eight weeks. The specific growth rate in diets 1 (control) and 6(10% boiled MSM) were similar and significantly (P<0.05) higher than the other dietary groups. The significantly lower growth performance of fish fed diets containing higher inclusion levels of both raw and boiled MSM might be due to incomplete elimination of the antinutritional factors present in MSM by boiling. Other methods of processing MSM to improve its nutritive value should be investigated. (7 page document)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Experiments were conducted in a controlled-environmental growth chamber to evaluate the response of two strains of the invasive submersed plant Hydrilla verticillata (L.f.) Royle to fluridone (1-methyl-3-phenyl-5-[3-trifluoromethyl)phenyl]- 4(1H)-pyridinone). (PDF has 6 pages.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

加卸载响应比理论的主要思路是 :系统在稳定状态时加载响应与卸载响应的比值与非稳定状态时加载响应与卸载响应的比值是完全不同的。大震前加卸载响应比升高和能量加速释放这两种现象可以用来对地震进行中期预报。同时 ,加卸载响应比理论和能量加速释放可能有相同的物理机制。为了验证这种地震预报方法的可行性 ,我们研究了几例发生在澳大利亚与中国 ,M 5 0~ 7 9之间的地震 ,其中包括破坏严重的澳大利亚纽卡斯尔地震和中国的唐山地震。我们利用以震源中心一定范围内的数据计算了震前的加卸载响应比和能量加速释放的幂律拟合。能量幂律加速释放存在一组最佳的拟合 ,一定范围内加卸载响应比达最大值表明加卸载响应比也有一个临界区尺度。进一步讲 ,加卸载响应比与能量加速释放的临界区尺度是相似的。这些结果表明加卸载响应比与能量加速释放有相同的物理机制。进一步的研究可能会对这种物理机制提供更好的解释 ,同时也能对地震的中期预报提供理论基础

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dense, monospecific cattail (Typha spp.) stands are a problem in many prairie wetlands because they alter habitat structure and function, resulting in a decrease in use by wildlife species. Cheyenne Bottoms Wildlife Area, a Wetland of International Importance in central Kansas, has experienced a large increase in cattails and a subsequent decrease in migratory wetland bird use. As a consequence, intensive cattail management is practiced. We assessed the effectiveness of prescribed burning, discing following prescribed burning, and cattle grazing following prescribed burning at two stocking rates of 5 and 20 head per 11 ha in suppressing cattail, as well as the effects of these treatments on non-cattail vegetation.