Taro （Colocasia esculenta L. Schott） is an important underutilised crop in South Africa, East Africa and Indonesia. Three taro landraces, namely, Dumbe Lomfula （wild）, KwaNgwanase and Umbumbulu, were collected fro...Taro （Colocasia esculenta L. Schott） is an important underutilised crop in South Africa, East Africa and Indonesia. Three taro landraces, namely, Dumbe Lomfula （wild）, KwaNgwanase and Umbumbulu, were collected from two locations in KwaZulu-Natal （KZN）, South Africa, and planted at two locations, Pietermaritzburg （KZN） and Roodeplaat, Pretoria. Ago-morphological characterisation of vegetative and corm characteristics were done four months after planting and at harvest, respectively. Sampling for DNA fingerprinting using five SSR primers was done using leaf material four months after planting. Agro-morphological characterisation was useful in showing differences between the wild landrace and the two cultivated landraces, as well as identification of dasheen and eddoe types. SSR primer characterisation showed that despite significant morphological difference, the wild Dumbe Lomfula and Umbumbulu landraces were closely related but different from the KwaNgwanase landrace. Although landraces showed great morphological variation, this did not necessarily imply genetic variation. It is concluded that SSR primers are more useful for characterising taro landraces.展开更多
An increasing interest of the economic operators on the bycatch of shrimp fishery endangers bycatch species to over-exploitation risks. This study provides a better knowledge regarding to the current status of one maj...An increasing interest of the economic operators on the bycatch of shrimp fishery endangers bycatch species to over-exploitation risks. This study provides a better knowledge regarding to the current status of one major component of the bycatches Otolithes argenteus （O. argenteus） caught in the shrimp fishery area along the West coast of Madagascar using the morphometric analysis. Individual body weight and body measurement were carried out on 565 specimens collected from the sale＇s society of seafood （SOPROMER） in the Capital city. Results show a high proportion of small fishes like as immature young individuals. A ＂negative allometry＂ growth type within the juveniles to become ＂isometric allometry＂ for the adult, large size was observed. Marine environment is favorable to the development for the whole population of the O. argenteus species. The morphometry approach helped to better understanding of the characteristics and the operating status of the O. argenteus population thus constitute as a tool in establishing a sustainable fisheries management strategy in Madagascar.展开更多
This paper discusses the asymptotic stability and Riesz basis generation for a general tree-shaped network of vibrating strings. All exterior vertices are assumed to be fixed and interior vertices are imposed linear d...This paper discusses the asymptotic stability and Riesz basis generation for a general tree-shaped network of vibrating strings. All exterior vertices are assumed to be fixed and interior vertices are imposed linear damping feedbacks. This paper shows that the system is well-posed and asymptotically stable by C0-semigroup theory. With some additional conditions, the spectrum of the system is shown to be located in a strip that is parallel to the imaginary axis and the set of all generalized eigenfunctions is completed in the state space. These lead to the conclusion that there is a sequence of generalized eigenfunctions of the system, which forms a Riesz basis with parenthesis for the state space.展开更多
文摘Taro （Colocasia esculenta L. Schott） is an important underutilised crop in South Africa, East Africa and Indonesia. Three taro landraces, namely, Dumbe Lomfula （wild）, KwaNgwanase and Umbumbulu, were collected from two locations in KwaZulu-Natal （KZN）, South Africa, and planted at two locations, Pietermaritzburg （KZN） and Roodeplaat, Pretoria. Ago-morphological characterisation of vegetative and corm characteristics were done four months after planting and at harvest, respectively. Sampling for DNA fingerprinting using five SSR primers was done using leaf material four months after planting. Agro-morphological characterisation was useful in showing differences between the wild landrace and the two cultivated landraces, as well as identification of dasheen and eddoe types. SSR primer characterisation showed that despite significant morphological difference, the wild Dumbe Lomfula and Umbumbulu landraces were closely related but different from the KwaNgwanase landrace. Although landraces showed great morphological variation, this did not necessarily imply genetic variation. It is concluded that SSR primers are more useful for characterising taro landraces.
文摘An increasing interest of the economic operators on the bycatch of shrimp fishery endangers bycatch species to over-exploitation risks. This study provides a better knowledge regarding to the current status of one major component of the bycatches Otolithes argenteus （O. argenteus） caught in the shrimp fishery area along the West coast of Madagascar using the morphometric analysis. Individual body weight and body measurement were carried out on 565 specimens collected from the sale＇s society of seafood （SOPROMER） in the Capital city. Results show a high proportion of small fishes like as immature young individuals. A ＂negative allometry＂ growth type within the juveniles to become ＂isometric allometry＂ for the adult, large size was observed. Marine environment is favorable to the development for the whole population of the O. argenteus species. The morphometry approach helped to better understanding of the characteristics and the operating status of the O. argenteus population thus constitute as a tool in establishing a sustainable fisheries management strategy in Madagascar.
基金This research is supported in part by the Natural Science Foundation of China under Grant No. 60874035 and by the Scientific Research Initiation Foundation of Civil Aviation University of China （08QD09X）.
文摘This paper discusses the asymptotic stability and Riesz basis generation for a general tree-shaped network of vibrating strings. All exterior vertices are assumed to be fixed and interior vertices are imposed linear damping feedbacks. This paper shows that the system is well-posed and asymptotically stable by C0-semigroup theory. With some additional conditions, the spectrum of the system is shown to be located in a strip that is parallel to the imaginary axis and the set of all generalized eigenfunctions is completed in the state space. These lead to the conclusion that there is a sequence of generalized eigenfunctions of the system, which forms a Riesz basis with parenthesis for the state space.
