The Sanjiang Plain, formed with confluence of the Amur River, Ussuri River and Songhua River, is one of the three major stretches of wetland in the world. The large-scale agricultural development on the Sanjiang Plain...The Sanjiang Plain, formed with confluence of the Amur River, Ussuri River and Songhua River, is one of the three major stretches of wetland in the world. The large-scale agricultural development on the Sanjiang Plain started at the end of the 40s of the 20th century. The low-lying terrain and frequent floods caused a lot of difficulties to the agricultural development in the area. Water conservancy program has always been the kernel in agricultural development on the Sanjiang Plain in its history. The entities involved in its development project from different levels, including the state, state farms and farmers. Thus far, we have used the findings of their analysis of the paddy field development process at one state farm to take a microscopic approach to shed light on the development of paddy fields by farms and farmers and their roles in subsequent rice production. Because paddy field management on the Sanjiang Plain is very broad, but its rice producing techniques and economic structure have a certain definite form, the microscopic approach to understanding the paddy field development process and rice fanning management structure on the level of farmers could be considered a success. This paper is intended to elucidate from a macroscopic perspective the characteristics of the rapid development of irrigation and drainage systems and paddy fields on the Sanjiang Plain. Sanjiang Plain is a flood plain, and so major infrastructure development was required, thereby necessitating this national project for flood control. As politics and an economic integrated body, state farms also contributed to the promotion of agricultural development. As principals for the development, the state and state farms are taken by this paper as the main objects of our analysis.展开更多
Foot-and-mouth disease(FMD)is an acute,highly infectious and pathogenic animal disease.In recent years,with the rapid development of the swine breeding industry in China,pig farms have shown a trend of larger-scale de...Foot-and-mouth disease(FMD)is an acute,highly infectious and pathogenic animal disease.In recent years,with the rapid development of the swine breeding industry in China,pig farms have shown a trend of larger-scale development.Large-scale pig farms employ standardized management,a high level of automation,and a strict_system.However,these farms have a large trading volume,and increased transmission intensity of FMD is noted inside the farm.At present,the main control measure against FMD is pig vaccination.However,a standard for immunization procedures is not available,and currently adopted immunization procedures have not been effectively and systematically evaluated.Taking a typical large-scale pig farm in China as the research subject and considering the breeding pattern,piggery structure,age structure and immunization procedures,an individual-based state probability model is established to evaluate the effectiveness of the immune procedure.Based on numerical simulation,it is concluded that the optimal immunization program involves primary immunization at 40 days of age and secondary immunization at 80 days of age for commercial pigs.Breeding boars and breeding sows are immunized 4 times a year,and reserve pigs are immunized at 169 and 259 days of age.According to the theoretical analysis,the average control reproduction number of individuals under the optimal immunization procedure in the farm is 0.4927.In the absence of immunization,the average is 1.7498,indicating that the epidemic cannot be controlled without immunization procedures.展开更多
Fish farming is a strategic activity for both the economy and food security of the Tocantins state. Nowadays, there are about eighty small fish farmers in the region of Divin6polis in Tocantins state. The technologica...Fish farming is a strategic activity for both the economy and food security of the Tocantins state. Nowadays, there are about eighty small fish farmers in the region of Divin6polis in Tocantins state. The technological level of fish farmers is low and it was found that only 30% of farmers could ever get to the point of selling fish. Therefore, the objective of this paper is to investigate which socioeconomic factors have influence on the fact of fish farmers in the region of Divin6polis and in Tocantins state reach a level of efficiency in production enough that the fish can be good for sale in the local market. To estimate this relation the logit model was chosen, with methodology based on the empirical model used in Musaba and Namukwambi. Following the production of fish farms in the Western of Tocantins state, the collect of the data, during 2012, were conduct with interviews of 30 fish farms, visiting them in their homes and applying a questionnaire. Through the use of econometric models of probability for limited dependent variables, it was found that factors such as participation in federal programs to transfer income, total area of water and production in ponds are key factors in determining the likelihood of producer to sell fish.展开更多
There has been an increasing global and local interest in developing renewable, clean, and cheap energy towards achieving Goal number 7 of the Sustainable Development Goals (SDG). However, decisions involving suitable...There has been an increasing global and local interest in developing renewable, clean, and cheap energy towards achieving Goal number 7 of the Sustainable Development Goals (SDG). However, decisions involving suitable and sustainable locations for renewable energy projects remain an important task. This study employed Geographic Information System (GIS) and Multi-Criteria Decision Analysis (MCDA) to spatially analyze and model wind farm site suitability in Nasarawa State. The aim is to integrate the environmental, social, and economic aspects of decision-making for identifying sustainable wind farm sites. The study distinguished between two sets of decision criteria: decision constraints and decision factors. The former defined the exclusion zones while the latter were standardized based on fuzzy logic to depict varying degrees of suitability across the State. The MCDA applied the weighted linear combination method, with relative weights generated through pairwise comparisons of the analytic hierarchy process to analyze three policy scenarios: equal weights, environmental/social priority, and economic priority scenario. A combination of resulting composite maps from the constraints and the factors gave the final suitability maps. The resulting suitability index (SI) for the respective policy scenario describes the degrees of suitability: Ideal locations were denoted by one (1) and the not suitable locations by zero (0), with values in-between depicting varying degrees of wind farm site suitability. Based on the SI, priority locations indicating areas with good prospects, in addition to the most suitable parcels of land, were identified and delineated. The composite decision constraint revealed that wind farm projects would not be viable in more than half (57.58%) of the State. Wind speed was the major constraint and accounted for the exclusion of 46.25%, with a mean fuzzy membership value of 0.2008 indicating low suitability across the State. Also, the average acceptable wind farm location for the three-policy scenario was 33.33% of the entire study area. Lafia, Obi, Keana, Awe, Nasarawa-Eggon, Wamba and Kokona LGAs were the identified priority Local Government Areas (LGAs). However, only Lafia, Obi, and Nasarawa-Eggon were consistent with changes in the policy objectives. All the priority LGAs have one or more of the most suitable parcels within their administrative boundaries except for Wamba. Despite the severe limitations of wind speed, substantial parts of Nasarawa State still provide great development potentials for wind energy. The “most suitable” locations in Lafia, Nasarawa-Eggon, and Obi LGAs should have first consideration for the development of wind energy in the State.展开更多
文摘The Sanjiang Plain, formed with confluence of the Amur River, Ussuri River and Songhua River, is one of the three major stretches of wetland in the world. The large-scale agricultural development on the Sanjiang Plain started at the end of the 40s of the 20th century. The low-lying terrain and frequent floods caused a lot of difficulties to the agricultural development in the area. Water conservancy program has always been the kernel in agricultural development on the Sanjiang Plain in its history. The entities involved in its development project from different levels, including the state, state farms and farmers. Thus far, we have used the findings of their analysis of the paddy field development process at one state farm to take a microscopic approach to shed light on the development of paddy fields by farms and farmers and their roles in subsequent rice production. Because paddy field management on the Sanjiang Plain is very broad, but its rice producing techniques and economic structure have a certain definite form, the microscopic approach to understanding the paddy field development process and rice fanning management structure on the level of farmers could be considered a success. This paper is intended to elucidate from a macroscopic perspective the characteristics of the rapid development of irrigation and drainage systems and paddy fields on the Sanjiang Plain. Sanjiang Plain is a flood plain, and so major infrastructure development was required, thereby necessitating this national project for flood control. As politics and an economic integrated body, state farms also contributed to the promotion of agricultural development. As principals for the development, the state and state farms are taken by this paper as the main objects of our analysis.
基金supported by the National Key Research and Development Program of China(2016YFD0501501)the National Natural Science Foundation of China under Grant(11601292,61873154,11801398)+4 种基金Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(20210009)General Youth Fund project in Shanxi Province(201901D211158)the 1331 Engineering Project of Shanxi Province,Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province(2019L0114)Key Projects of Health Commission of Shanxi Province(No.2020XM18)the Key Research and Development Project in Shanxi Province(202003D31011/GZ).
文摘Foot-and-mouth disease(FMD)is an acute,highly infectious and pathogenic animal disease.In recent years,with the rapid development of the swine breeding industry in China,pig farms have shown a trend of larger-scale development.Large-scale pig farms employ standardized management,a high level of automation,and a strict_system.However,these farms have a large trading volume,and increased transmission intensity of FMD is noted inside the farm.At present,the main control measure against FMD is pig vaccination.However,a standard for immunization procedures is not available,and currently adopted immunization procedures have not been effectively and systematically evaluated.Taking a typical large-scale pig farm in China as the research subject and considering the breeding pattern,piggery structure,age structure and immunization procedures,an individual-based state probability model is established to evaluate the effectiveness of the immune procedure.Based on numerical simulation,it is concluded that the optimal immunization program involves primary immunization at 40 days of age and secondary immunization at 80 days of age for commercial pigs.Breeding boars and breeding sows are immunized 4 times a year,and reserve pigs are immunized at 169 and 259 days of age.According to the theoretical analysis,the average control reproduction number of individuals under the optimal immunization procedure in the farm is 0.4927.In the absence of immunization,the average is 1.7498,indicating that the epidemic cannot be controlled without immunization procedures.
文摘Fish farming is a strategic activity for both the economy and food security of the Tocantins state. Nowadays, there are about eighty small fish farmers in the region of Divin6polis in Tocantins state. The technological level of fish farmers is low and it was found that only 30% of farmers could ever get to the point of selling fish. Therefore, the objective of this paper is to investigate which socioeconomic factors have influence on the fact of fish farmers in the region of Divin6polis and in Tocantins state reach a level of efficiency in production enough that the fish can be good for sale in the local market. To estimate this relation the logit model was chosen, with methodology based on the empirical model used in Musaba and Namukwambi. Following the production of fish farms in the Western of Tocantins state, the collect of the data, during 2012, were conduct with interviews of 30 fish farms, visiting them in their homes and applying a questionnaire. Through the use of econometric models of probability for limited dependent variables, it was found that factors such as participation in federal programs to transfer income, total area of water and production in ponds are key factors in determining the likelihood of producer to sell fish.
文摘There has been an increasing global and local interest in developing renewable, clean, and cheap energy towards achieving Goal number 7 of the Sustainable Development Goals (SDG). However, decisions involving suitable and sustainable locations for renewable energy projects remain an important task. This study employed Geographic Information System (GIS) and Multi-Criteria Decision Analysis (MCDA) to spatially analyze and model wind farm site suitability in Nasarawa State. The aim is to integrate the environmental, social, and economic aspects of decision-making for identifying sustainable wind farm sites. The study distinguished between two sets of decision criteria: decision constraints and decision factors. The former defined the exclusion zones while the latter were standardized based on fuzzy logic to depict varying degrees of suitability across the State. The MCDA applied the weighted linear combination method, with relative weights generated through pairwise comparisons of the analytic hierarchy process to analyze three policy scenarios: equal weights, environmental/social priority, and economic priority scenario. A combination of resulting composite maps from the constraints and the factors gave the final suitability maps. The resulting suitability index (SI) for the respective policy scenario describes the degrees of suitability: Ideal locations were denoted by one (1) and the not suitable locations by zero (0), with values in-between depicting varying degrees of wind farm site suitability. Based on the SI, priority locations indicating areas with good prospects, in addition to the most suitable parcels of land, were identified and delineated. The composite decision constraint revealed that wind farm projects would not be viable in more than half (57.58%) of the State. Wind speed was the major constraint and accounted for the exclusion of 46.25%, with a mean fuzzy membership value of 0.2008 indicating low suitability across the State. Also, the average acceptable wind farm location for the three-policy scenario was 33.33% of the entire study area. Lafia, Obi, Keana, Awe, Nasarawa-Eggon, Wamba and Kokona LGAs were the identified priority Local Government Areas (LGAs). However, only Lafia, Obi, and Nasarawa-Eggon were consistent with changes in the policy objectives. All the priority LGAs have one or more of the most suitable parcels within their administrative boundaries except for Wamba. Despite the severe limitations of wind speed, substantial parts of Nasarawa State still provide great development potentials for wind energy. The “most suitable” locations in Lafia, Nasarawa-Eggon, and Obi LGAs should have first consideration for the development of wind energy in the State.
