In recent years, the Mekong delta has been strongly developed both for agriculture and aquaculture. However, there is scope for a negative impact of agriculture on aquaculture in term of production and quality of seafood products. Specifically, the large amount of pesticides imported and used in the Mekong delta not only help agriculture purposes but can also easily enter aquatic systems and affect aquaculture. Pesticides can be transported in the environment by chemo-dynamic procedures and hydrological processes. As a result, pesticides used in agriculture become dispersed and their residues in sediment, water and biota have been detected in the Mekong delta. This study investigated the overall pesticide process including pesticide use, modelling pesticide accumulation and evaluating the potential impact on aquaculture sites for some target aquatic species. The risk of pesticides use in the Mekong delta was addressed in three stages: (1) investigating current pesticide use status in the Mekong delta; (2) modelling pesticide loss and accumulation; (3) classifying pesticide risk areas for aquaculture of target cultured species. A survey of 334 farms covering a total area of ~20,000km2 in the Mekong delta took place between 2008 and 2009. Information on pesticide types and quantities was recorded using questionnaires, and it was found that 96 pesticides in 23 groups were popularly used for agricultural purposes. Dicarboximide, Carbamate and Conazole had the highest use at ~3000, ~2000 and ~2000 g/ha/year respectively. The survey revealed an increase in pesticide use per hectare since previous surveys in the Mekong delta in 1994, 2000, and 2004. However, the highly persistent compounds (WHO classification classes II, III and IV) appeared to have reduced in use. Insecticides previously represented >50% of the total pesticides used, however, the resent survey has shown their use has decreased to ~38%.There was a parallel increase in use of fungicides from previous levels of <30% of total pesticides to more recently ~41%. The combination of pesticide information and geo-location data enabled display and analysis of this data spatially using a Geographic Information System (GIS). A pesticide loss and accumulation model was established through combination of several sub-models including sediment loss and accumulation, direct loss, and water runoff, all of which were implemented and integrated within the GIS environment. MUSLE (Modified Universal Soil Loss Equation) was used to estimate sediment loss and accumulation in the Mekong delta and the Curve Number method (CN Method) was applied to predict water runoff and discharges and flow accumulation. Modelling commenced from the first pesticide application in April, based on 4 day time-steps. All mathematical calculations run within each time step automatically reiterated in the following time step with the new input datasets. The results from fuzzy classification of the pesticide model outcomes were considered in terms of the 96hr lethal concentration (LC50) in order to classify the risk and non-risk areas for catfish and tiger shrimp culture. The sediment loss and accumulation model shows that the highest loss of sediment was in the rainy season, especially in May to October. Vegetables and short term crop areas were found be most strongly eroded. The MUSLE model showed that the highest sediment accumulation was in the hilly areas (~1066.42 tonne/ha/year); lower in riverside areas (~230.39 tonne/ha/year) and lowest in flooded paddy areas (~150.15tonne/ha/year). Abamectin was used as an example throughout this study to estimate pesticide loss and its effects on aquaculture. The results showed that pesticide loss by runoff and sediment loss is less than the loss by half-life degradation (for Abamectin specifically). Accumulation of Abamectin occurred at highest rate in May and October and decreased with time. The spatial models showed that pesticide residues concentrated in the river and riverside areas. In order to evaluate the acute toxicity impacts, three levels of water depth in ponds were modelled as culture depths for catfish and tiger shrimp. The results show that the highest risk areas for catfish occurred in May and October with ~333,000 and ~420,000 ha at a pond depth of 0.5 m; ~136,000 and ~183,000 ha at a pond depth of 1.0 m; and ~10,840 and ~19,000 ha at a pond depth of 1.5 m. Risk areas for catfish mainly concentrated at the riverside and in part of the coastal areas. For tiger shrimp, the risk periods during the year were similar to those found for catfish. The highest risk areas for shrimp were ~648,000 and ~771,000 ha at 0.5 m pond depth; ~346,000 and ~446,700 ha at 1.0 m pond depth; and ~185,000 and ~250,000 ha at 1.5 m pond depth. Overall, deeper ponds reduced the risk. This study has developed a method to evaluate the negative impact of input pesticides to the environment from agricultural use related to fluctuation of aquaculture risk areas. The research indicates the potential relationship between pesticide input and the risk areas for aquaculture. The model has several significant uses: 1) it can provide information to policy makers for a more harmonized development of both aquaculture and agriculture in the Mekong delta in the future, 2) it provides data for aquaculture investment analysis to decrease the hazards caused by pesticide impacts, and 3) it provides a model capable of application to wide field scenarios and suitable for any pesticide type.

Cette recherche interroge l’existence des nouvelles formes de ruralité émergentes dans le bassin métropolitain du delta du Yangzi. En opposition à l’écart croissant entre patrimoine infrastructurel et société on réaffirme la priorité du territoire comme principe théorique et paradigme naturel. L’analyse des processus historiques d’aménagement du territoire agricole à partir des réformes foncières et des pratiques autochtones de « Guangxi » (réseaux sociaux), a révélé une restructuration des ressources stratégiques du territoire du delta avant la réorganisation des espaces ruraux bâtis : la nature du sol et le réseau de l’eau. En même temps dispositif de contrôle politique et de développement social, la modification de l’infrastructure territoriale jusqu’ à la fin du maoïsme, peut être interprétée comme un investissement sur le long terme du capital humain et environnemental. Notre hypothèse est que la diffusion des petites et moyennes entreprises dans les zones rurales représente une forme de capitalisation des matrices sociales et organisationnelles du tissu agricole plus ancien. Ces transformations ont amené à la formation de nombreux espaces hybrides et clusters des entreprises dispersées dans la campagne qui s’appuient de façon complémentaire aux réseaux environnementaux préexistants. En conséquence, ce mode de production a à son tour, remodelé la relation entre l'économie, les communautés et l'environnement naturel locaux donnant lieu à des formes du développement sans fractures, plus ductiles et résilientes où la relation entre l'espace construit et l'espace agricole n'est plus de nature opposée. Ce qui émerge est un réseau de “milieux” dont chaque élément rend compte de la conception d’un paysage, de matériaux propres, de méthodes et procédures de construction. L’organisation morphologique qui en résulte montre un modèle d'urbanisation capillaire dans ces zones conventionnellement définies « non-urbaines ». Interroger ces formes émergentes de ruralité veut dire réviser la façon de conceptualiser la notion du « territoire métropolitain », et notamment de ce que on définis l’ « urbain ». On fait valoir, finalement, pour un besoin urgent de reconsidérer la séquence programmatique qui sous-tendent la morphologie spatiale de régions mégalopolitaines, par la prise en compte des rapports de continuité entre « milieux » et « communauté » et par le biais d'un examen des interactions entre ces réalités souvent, disjoints / The territorial scale and the form of the territory are fundamental basis to understand metropolitan processes and the changes occurred in its spatial, economic and social structure. The centrality of landforms and of their dynamics inspires more situated approaches, in which the agency of natural elements is integrated. This research investigates the existence of new forms of emerging rurality in the metropolitan basin of the Yangtze Delta. In opposition to the growing gap between infrastructural heritage and society, the priority of the territory is reaffirmed as a theoretical tool and environmental paradigm. The research hypothesis is that the spread of small and medium-sized enterprises in rural areas represents a form of capitalization of the spatial reorganization occurred in the Commune's period. The preliminary factor which originated the process of rural industrialization is based on the restructuring of two strategic territorial resources: the soil structure and the water network. These transformations have led to the formation of numerous hybrid spaces and clusters of small and micro enterprises dispersed over the countryside. As a result, this mode of production has, in turn, reshaped the relationship between the local economy, communities and natural environment giving rise to forms of urban development without fractures, where the relationship between the built space and the agricultural area is no longer of an opposite nature. What emerges is a network of "milieu” where the resulting socio-spatial organization shows a pattern of capillary urbanization in these conventionally defined "non-urban" areas. The notion of urban is changing and ecological rationality can offer fundamental opportunities to analyse, intersect and integrate the various territorial layers

Poon Fung Ting. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 152-166). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.ii / ABSTRACT --- p.iii / TABLE OF CONTENTS --- p.vi / LIST OF TABLES --- p.ix / LIST OF FIGURES --- p.x / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Research Questions --- p.1 / Chapter 1.2 --- Research Objectives --- p.3 / Chapter 1.3 --- Definitions --- p.4 / Chapter 1.4 --- Research Design --- p.9 / Chapter 1.5 --- Outline of the Thesis --- p.11 / Chapter CHAPTER 2 --- BACKGROUND OF THE STUDY AND THE LITERATURE REVIEW --- p.13 / Chapter 2.1 --- Introduction --- p.13 / Chapter 2.2 --- Background of the Study --- p.15 / Chapter 2.3 --- Literature Review --- p.28 / Chapter 2.4 --- Summary --- p.38 / Chapter CHAPTER 3 --- SPATIAL PATTERNS OF NON-HUKOU MIGRANTS IN THE PEARL RIVER DELTA --- p.41 / Chapter 3.1 --- Introduction --- p.41 / Chapter 3.2 --- Proportion of Non-hukou Migrants --- p.44 / Chapter 3.3 --- Distribution of Migrants --- p.47 / Chapter 3.4 --- Sources of Migrants --- p.50 / Chapter 3.5 --- The PRD as a Destination --- p.56 / Chapter 3.6 --- Gender Ratio of Non-hukou Migrants --- p.64 / Chapter 3.7 --- Spatial Patterns and Correlation of Migration Indicators --- p.67 / Chapter 3.8 --- Summary --- p.79 / Chapter CHAPTER 4 --- ANALYZING THE DETERMINANTS OF NON-HUKOU POPULATION IN COUNTY-LEVEL AREAS --- p.83 / Chapter 4.1 --- Introduction --- p.83 / Chapter 4.2 --- Method --- p.84 / Chapter 4.3 --- Variables --- p.86 / Chapter 4.4 --- The Results --- p.90 / Chapter 4.5 --- Summary --- p.102 / Chapter CHAPTER 5 --- IMPACTS OF NON-HUKOU MIGRANTS AND THE POLICY RESPONSES --- p.104 / Chapter 5.1 --- Introduction --- p.104 / Chapter 5.2 --- The Trend of Non-hukou Migrants in PRD --- p.106 / Chapter 5.3 --- Positive Impacts --- p.110 / Chapter 5.4 --- Negative Impacts --- p.115 / Chapter 5.5 --- Policy Responses --- p.121 / Chapter 5.6 --- Summary --- p.139 / Chapter CHAPTER 6 --- CONCLUSION --- p.142 / Chapter 6.1 --- Non-hukou Migration in PRD --- p.142 / Chapter 6.2 --- Policy Responses --- p.147 / Chapter 6.3 --- Suggestions for Further Research --- p.150 / REFERENCES --- p.152

Man Chi-shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 198-205). / Abstracts in English and Chinese. / List of Tables --- p.i. / Abstract --- p.ii. / 摘要 --- p.iii. / Acknowledgement --- p.iv. / Chapter Chapter 1 --- Going into migrants in the Pearl River Delta --- p.1 / Chapter I --- The living strategy besides political resistance --- p.2 / Chapter II --- Exploring the migrants in township-and-village areas of the Pearl River Delta --- p.6 / Chapter III --- Methodology --- p.9 / Chapter IV --- Overview of this study --- p.13 / Chapter V --- Terms clarification --- p.14 / Chapter Chapter 2 --- Literature review: understanding migrants in South China --- p.16 / Chapter I --- Migration --- p.18 / Chapter II --- Floating population in China after the economic reforms --- p.22 / Chapter III --- Theoretical framework --- p.38 / Chapter Chapter 3 --- A dichotomous community: the construction of oppressed and oppressor in Tianshen Township --- p.59 / Chapter I --- Going down to the field site --- p.60 / Chapter II --- Unequal relationships between the oppressed and the oppressor --- p.73 / Chapter III --- Concluding remarks --- p.97 / Chapter Chapter 4 --- "The voice from migrants: ""The outside world is splendid, but also ruthless.""" --- p.102 / Chapter I --- Living experience --- p.103 / Chapter II --- Working experience --- p.110 / Chapter III --- Floating: a short stage of life --- p.117 / Chapter IV --- Concluding remarks --- p.131 / Chapter Chapter 5 --- Exit and familism: the ways to accommodate dissatisfaction --- p.135 / Chapter I --- The infrequency of direct confrontation --- p.136 / Chapter II --- Job switching as a from of self-defense --- p.140 / Chapter III --- The significance of family support --- p.148 / Chapter IV --- A case study: the entanglement between survival and exploitation --- p.157 / Chapter V --- Concluding remarks --- p.163 / Chapter Chapter 6 --- Economic retreatism: the basic reason of the social stability in the Pearl River Delta --- p.168 / Chapter I --- A comparison with Scott's and Popkin's cases --- p.169 / Chapter II --- A supplement to previous studies concerning Chinese migrant workers --- p.180 / Chapter III --- Suggestions --- p.182 / Chapter IV --- Prediction --- p.184 / Chapter V --- IEpilogue --- p.185 / Appendix A: List of Interviewees --- p.189 / Appendix B: Photos --- p.190 / Appendix C : Cartoon --- p.195 / Appendix D: Map --- p.197 / Bibliography --- p.198

Xu, Fang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 75-79). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.ii / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background Information --- p.3 / Chapter 2.1 --- Growth of Air-Transportation Industry --- p.3 / Chapter 2.1.1 --- General Figures --- p.3 / Chapter 2.1.2 --- Growth of Air Cargo Market --- p.3 / Chapter 2.1.3 --- Regulatory Support --- p.5 / Chapter 2.2 --- The Focus: Pearl River Delta --- p.6 / Chapter 2.2.1 --- Strategic Moves of Airports --- p.8 / Chapter 2.2.2 --- Investment and Development of Airlines --- p.12 / Chapter 2.2.3 --- Hong Kong VS Shen Zhen --- p.13 / Chapter 3 --- Airport Competition --- p.14 / Chapter 3.1 --- Introduction --- p.14 / Chapter 3.2 --- One-period two port competition model --- p.15 / Chapter 3.2.1 --- The basic model --- p.15 / Chapter 3.2.2 --- Stackelberg Game --- p.23 / Chapter 3.2.3 --- Location factor --- p.26 / Chapter 3.3 --- Two-period two port competition model --- p.27 / Chapter 3.3.1 --- The basic model --- p.27 / Chapter 3.3.2 --- Switching cost --- p.30 / Chapter 3.4 --- Conclusion --- p.33 / Chapter 4 --- Combined airline VS full-cargo airline --- p.34 / Chapter 4.1 --- Introduction --- p.34 / Chapter 4.2 --- Model Setup --- p.35 / Chapter 4.2.1 --- Modelling Capacity and Cost --- p.35 / Chapter 4.2.2 --- Modelling Demand --- p.37 / Chapter 4.2.3 --- The Optimization Framework --- p.37 / Chapter 4.2.4 --- Decomposition of the Decision Process --- p.39 / Chapter 4.3 --- Step 1: Strategies in the Passenger Market --- p.40 / Chapter 4.3.1 --- Carriers enter the game with zero-inventory --- p.40 / Chapter 4.3.2 --- Incumbent carrier has established initial capacity --- p.42 / Chapter 4.4 --- Step 2: Strategies in the Cargo Market --- p.45 / Chapter 4.5 --- Centralized decision --- p.49 / Chapter 4.5.1 --- Both airlines have zero initial capacity in the passenger market --- p.50 / Chapter 4.5.2 --- One airline has non-zero initial capacity in the passenger market --- p.51 / Chapter 4.5.3 --- Both airlines have initial capacity in the cargo market --- p.53 / Chapter 4.6 --- Conclusion --- p.53 / Chapter 5 --- Demand growth and shifting --- p.55 / Chapter 5.1 --- Introduction --- p.55 / Chapter 5.2 --- Competition Scenario --- p.56 / Chapter 5.2.1 --- Growth and shifting of passenger demand --- p.56 / Chapter 5.2.2 --- Growth and shifting of cargo demand --- p.60 / Chapter 5.3 --- Centralized decision making --- p.64 / Chapter 5.4 --- conclusion --- p.72 / Chapter 6 --- Conclusion --- p.73 / Bibliography --- p.75

published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning

Rice and maize are global staple food and play an important role in world’s food security strategy. Vietnam is one of rice leading export countries but annually it has to import a considerate amount of maize for cattle food processing. Red River Delta in the north of Vietnam is the second rice bucket of the country, which is responsible formore than 20% of total rice production. The priority crops in the areas are rice and maize and rice-maize system is the leading cropping system in the area. Currently, it is reported that the rice-maize cropping system is not sustainable and its profit is reducing in most of production areas in the Red River Delta. Improving rice cropping system aims is not only to increase rice and maize yields and production but also to improve the land use efficiency, decline the cost of the production and to increase system sustainability. To increase sustainability there must be a linkage of various factors. This review emphasizes on increasing rice-maize crop sustainability by applying appropriate agriculture practices such as reducing chemical fertilization and intensive tillage. / Gạo và ngô là nguồn lương thực chính cho toàn cầu và đóng một vai trò quan trọng trong chiến lược an ninh lương thực của thế giới. Việt Nam là một trong những nước dẫn đầu về xuất khẩu gạo nhưng hàng năm vẫn phải nhập một số lượng lớn ngô để chế biến thức ăn gia súc. Đồng bằng sông Hồng là một trong hai vựa lúa lớn của Việt Nam sản xuất khoảng 20% sản lượng lúa gạo của cả nước. Ở đồng bằng sông Hồng, lúa và ngô là hai cây trồng chính là hệ canh tác lúa-ngô là cơ cấu cây trồng hàng đầu trong vùng. Tuy nhiên, trong những năm gần đây, rất nhiều đánh giá cho thấy hệ thống canh tác lúa-ngô là hệ thống canh tác không bền vững và các lợi nhuận của mang lại từ cơ cấu canh tác ở hầu hết các khu vực sản xuất ở vùng đồng bằng sông Hồng của Việt Nam đã và đang giảm dần. Do đó, việc cải thiện cơ cấu canh tác lúa-ngô không chỉ nhằm mục đích tăng năng suất lúa và ngô mà còn nâng cao hiệu quả sử dụng đất, giảm chi phí sản xuất và tăng cường hệ thống canh tác bền vững. Tuy nhiên, để tăng tính bền vững của hệ thống canh tác thì phải liên kết nhiều yếu tố khác nhau. Bài viết này dựa vào các kết quả nghiên cứu của các tác giả khác nhau để đưa ra những giải pháp tích cực làm tăng tính bền vững của hệ thống canh tác lúa-ngô bằng cách áp dụng các phương pháp canh tác hợp lý như giảm sử dụng phân hóa học và các biện pháp canh tác thâm canh như áp dụng phương pháp làm đất tối thiểu.

published_or_final_version / abstract / toc / Transport Policy and Planning / Master / Master of Arts in Transport Policy and Planning

published_or_final_version / Real Estate and Construction / Doctoral / Doctor of Philosophy

Rice and maize are global staple food and play an important role in world’s food security strategy. Vietnam is one of rice leading export countries but annually it has to import a considerate amount of maize for cattle food processing. Red River Delta in the north of Vietnam is the second rice bucket of the country, which is responsible formore than 20% of total rice production. The priority crops in the areas are rice and maize and rice-maize system is the leading cropping system in the area. Currently, it is reported that the rice-maize cropping system is not sustainable and its profit is reducing in most of production areas in the Red River Delta. Improving rice cropping system aims is not only to increase rice and maize yields and production but also to improve the land use efficiency, decline the cost of the production and to increase system sustainability. To increase sustainability there must be a linkage of various factors. This review emphasizes on increasing rice-maize crop sustainability by applying appropriate agriculture practices such as reducing chemical fertilization and intensive tillage. / Gạo và ngô là nguồn lương thực chính cho toàn cầu và đóng một vai trò quan trọng trong chiến lược an ninh lương thực của thế giới. Việt Nam là một trong những nước dẫn đầu về xuất khẩu gạo nhưng hàng năm vẫn phải nhập một số lượng lớn ngô để chế biến thức ăn gia súc. Đồng bằng sông Hồng là một trong hai vựa lúa lớn của Việt Nam sản xuất khoảng 20% sản lượng lúa gạo của cả nước. Ở đồng bằng sông Hồng, lúa và ngô là hai cây trồng chính là hệ canh tác lúa-ngô là cơ cấu cây trồng hàng đầu trong vùng. Tuy nhiên, trong những năm gần đây, rất nhiều đánh giá cho thấy hệ thống canh tác lúa-ngô là hệ thống canh tác không bền vững và các lợi nhuận của mang lại từ cơ cấu canh tác ở hầu hết các khu vực sản xuất ở vùng đồng bằng sông Hồng của Việt Nam đã và đang giảm dần. Do đó, việc cải thiện cơ cấu canh tác lúa-ngô không chỉ nhằm mục đích tăng năng suất lúa và ngô mà còn nâng cao hiệu quả sử dụng đất, giảm chi phí sản xuất và tăng cường hệ thống canh tác bền vững. Tuy nhiên, để tăng tính bền vững của hệ thống canh tác thì phải liên kết nhiều yếu tố khác nhau. Bài viết này dựa vào các kết quả nghiên cứu của các tác giả khác nhau để đưa ra những giải pháp tích cực làm tăng tính bền vững của hệ thống canh tác lúa-ngô bằng cách áp dụng các phương pháp canh tác hợp lý như giảm sử dụng phân hóa học và các biện pháp canh tác thâm canh như áp dụng phương pháp làm đất tối thiểu.