In mineral exploration, the apparent resistivity and apparent frequency （or apparent polarizability） parameters of induced polarization method are commonly utilized to describe the induced polarization anomaly. When...In mineral exploration, the apparent resistivity and apparent frequency （or apparent polarizability） parameters of induced polarization method are commonly utilized to describe the induced polarization anomaly. When the target geology structure is significantly complicated, these parameters would fail to reflect the nature of the anomaly source, and wrong conclusions may be obtained. A wavelet approach and a metal factor method were used to comprehensively interpret the induced polarization anomaly of complex geologic bodies in the Adi Bladia mine. Db5 wavelet basis was used to conduct two-scale decomposition and reconstruction, which effectively suppress the noise interference of greenschist facies regional metamorphism and magma intrusion, making energy concentrated and boundary problem unobservable. On the basis of that, the ore-induced anomaly was effectively extracted by the metal factor method.展开更多
lntra-regional fish trade has potential in addressing the region＇s food and nutrition insecurity, as well as poverty reduction, by enabling movement of fish from countries of surplus to those with deficit. However, i...lntra-regional fish trade has potential in addressing the region＇s food and nutrition insecurity, as well as poverty reduction, by enabling movement of fish from countries of surplus to those with deficit. However, informal fish trade, just like all informal economic activities, has been overlooked and neglected in many national and regional policies, leading to obscurity of such an important part of the fisheries sector. This study examined the situation in the cross-border informal fish trade in order to deepen our understanding about the traders, the factors influencing the traders to use informal trade channels, the structure of the products traded and the challenges traders face, as well as propose policy direction to enhance the cross-border fish trade in the Southern Africa region. The study revealed that female traders dominated informal fish trade. In both Malawi and Zambia, an estimated 45,285.52 metric tonnes of fish valued at 82.14 million dollars and 102,263.9 metric tolmes of fish valued at 3.3 million dollars were informally traded. The key species involved in informal cross-border trade in Malawi and Zambia were the small pelagics, usipa （Engraulicypris sardella） from Lake Malawi and dagaa （Rastrineobola argentea） from Lake Tanganyika, respectively. It emerged from focus group discussions with informal fish traders and key informants＇ interviews with border post fish inspection and revenue collection officials that traders are put off by the cross-border regulations. Therefore, it is important for countries in the Southern African Development Community （SADC） region to regularize and formalize cross-border trade, particularly in small pelagic fish species, since this species plays a great role in the livelihoods, food and nutrition security of many people in the region, especially the rural and urban poor. It is also important for governments to support processors and traders to improve the quality of fish being traded, and decentralize issuing of the import/export certificates and other cross-border support documents. Lastly, there is a need to establish informal fish trade monitoring systems to adequately quantify the volumes traded.展开更多
基金Project(41174103)supported by the National Natural Science Foundation of ChinaProject(2010-211)supported by the Foreign Mineral Resources Venture Exploration Special Fund of China
文摘In mineral exploration, the apparent resistivity and apparent frequency （or apparent polarizability） parameters of induced polarization method are commonly utilized to describe the induced polarization anomaly. When the target geology structure is significantly complicated, these parameters would fail to reflect the nature of the anomaly source, and wrong conclusions may be obtained. A wavelet approach and a metal factor method were used to comprehensively interpret the induced polarization anomaly of complex geologic bodies in the Adi Bladia mine. Db5 wavelet basis was used to conduct two-scale decomposition and reconstruction, which effectively suppress the noise interference of greenschist facies regional metamorphism and magma intrusion, making energy concentrated and boundary problem unobservable. On the basis of that, the ore-induced anomaly was effectively extracted by the metal factor method.
文摘lntra-regional fish trade has potential in addressing the region＇s food and nutrition insecurity, as well as poverty reduction, by enabling movement of fish from countries of surplus to those with deficit. However, informal fish trade, just like all informal economic activities, has been overlooked and neglected in many national and regional policies, leading to obscurity of such an important part of the fisheries sector. This study examined the situation in the cross-border informal fish trade in order to deepen our understanding about the traders, the factors influencing the traders to use informal trade channels, the structure of the products traded and the challenges traders face, as well as propose policy direction to enhance the cross-border fish trade in the Southern Africa region. The study revealed that female traders dominated informal fish trade. In both Malawi and Zambia, an estimated 45,285.52 metric tonnes of fish valued at 82.14 million dollars and 102,263.9 metric tolmes of fish valued at 3.3 million dollars were informally traded. The key species involved in informal cross-border trade in Malawi and Zambia were the small pelagics, usipa （Engraulicypris sardella） from Lake Malawi and dagaa （Rastrineobola argentea） from Lake Tanganyika, respectively. It emerged from focus group discussions with informal fish traders and key informants＇ interviews with border post fish inspection and revenue collection officials that traders are put off by the cross-border regulations. Therefore, it is important for countries in the Southern African Development Community （SADC） region to regularize and formalize cross-border trade, particularly in small pelagic fish species, since this species plays a great role in the livelihoods, food and nutrition security of many people in the region, especially the rural and urban poor. It is also important for governments to support processors and traders to improve the quality of fish being traded, and decentralize issuing of the import/export certificates and other cross-border support documents. Lastly, there is a need to establish informal fish trade monitoring systems to adequately quantify the volumes traded.
