Management challenges of freshwater fisheries in Africa

The freshwater fisheries of Africa are important sources of income and protein for the people of the continent, and stocks of biodiversity for the world. This report discusses the experience for eight important lakes (Baringo, Chad, Kariba, Malawi, Naivasha, Nakuru, Tanganyika and Victoria), in order to provide an overview of the challenges facing the African freshwater systems, the interventions undertaken to manage the challenges, the inputs that have been required, and the lessons learned to guide further actions. In particular, the experience of the Global Environment Facility in promoting sustainable fisheries and lake basin management at five of these lakes (Baringo, Chad, Malawi, Tanganyika and Victoria) is discussed. The overall experience to date indicates a lack of effective management actions, as a result of limited accessibility and application of scientific information, poor dissemination of management information, inappropriate and un‐harmonized fishery laws and regulations, inadequate enforcement of existing laws and regulations, weak institutions and institutional processes, and inadequate funds for implementing fishery programmes.     

论中日东海油气争端及其有效解决途径

随着世界经济的发展，东海油气资源对中日两国经济发展的战略意义日趋重要，随之而来的两国对在东海资源开采权争议的磋商也越来越热烈。现阶段中日双方对东海的权利要求争执不下，对于双方都没有好处。结合东海地域特点、联合国海洋法的具体规定和相关国际法庭的司法实践的具体分析，探讨对东海油气争端的解决方法。对国内石油石化企业如何面对争端、抓住机遇提出看法。     

东海春晓构造成藏条件分析

本文应用钻井地质、地球物理和化验分析等资料，对春晓构造的始新统成藏条件进行了较详细深入的分析研究，认为本构造圈闭面积大，储层、盖层及遮挡条件良好，并处于生烃凹陷之中，油源充足，具有形成大-中型油气田有利条件。     

Analysing NDVI for the African continent using the geostationary meteosat second generation SEVIRI sensor

This study presents first results on Normalized Difference Vegetation Index (NDVI), from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensor onboard the geostationary satellite Meteosat Second Generation (MSG) covering the African continent. With a temporal resolution of 15 min MSG offers complementary information for NDVI monitoring compared to vegetation monitoring based on polar orbiting satellites. The improved temporal resolution has potential implications for accurate NDVI assessment of the African continent; e.g. the increased amount of available scenes are expected to help overcome problems related to cloud cover which makes the MSG data particularly well suited for early warning systems. Time series of 2004 MSG NDVI was compared to MODIS (Moderate Resolution Imaging Spectroradiometer) Terra and Aqua NDVI for the Dahra site in the Senegalese Sahel, West Africa. It was found that NDVI was available for 82 days with multiple cloud free acquisitions per day during the growing season as compared to 47 days with information from either MODIS Terra or Aqua for that particular site. Differences in MSG SEVIRI and MODIS BRDF on a seasonal scale were found to influence the time series of NDVI for the test site; MSG NDVI being higher than MODIS in July-August and lower in October-November. Preliminary composite analysis suggests that the period of compositing to produce continent scale cloud free products can be reduced to ∼5 days using MSG NDVI as compared to polar orbiting data. With the availability of diurnal reflectance information the significance of differences between the red and near-infrared wavelengths due to anisotropy become evident, causing diurnal variations in observed NDVI. Diurnal MSG NDVI was compared to in situ measured MSG NDVI at the test site in Senegal and the same “bowl-shaped” diurnal curve was found for a medium dense cover of annual grasses. The range in observed NDVI and time of diurnal minimum was different due to different viewing geometry. Daily minimum of in situ measured NDVI was around solar noon whereas minimum MSG NDVI occurs one hour prior to noon due to the test site location 12° west of the satellite sensor. Diurnal variation in observed NDVI was studied for a number of pixels characterized by different sensor view zenith angles and vegetation types. This analysis illustrated the diurnal NDVI dependency of illumination conditions, view angle and vegetation intensity and pinpoints the importance of proper BRDF modeling to produce daily values of MSG NDVI normalized for acquisition time, which will be the subject of a forthcoming paper.     

东、南海近岸海域环境综合调查中γ能谱数据浅析

广东省环境辐射研究监测中心（GERC）能谱室 ，在1999年国家环境保护总局组织开展的东、南海近岸海域环境综合调查工作中，承担了13个测站共24个样品（沉积物9个，海水13个和海鱼2个）的天然放射性核素（238U，226Ra,232Th,40K)及人工放射性核素137Cs含量的测量工作，本文主要介绍测量结果及对数据的初分析。结果显示，对大亚湾核电站周围近海各类样品，本次测量结果与常规监测（1993年12月－1998年12月）结果及本底调查（1990年12月－1992年3月）结果之间，均没有发现显著性差异，且与广东省内其他测站的样品之间，也未见显著性差异。     

�����Ӹ�������ĵ�����������̽��������

卧龙河气田位于四川盆地东部，是盆地内的大气田之一。它具有多产层、多储集类型、多气藏类型和多裂缝系统的特点，是四川复杂气田的典型代表。文章通过对该气田的解剖，总结出了碳酸盐岩复杂气田的地质特征，即地层发育较全，沉积具多旋回性；纵向为多构造层叠置，组成不协调型褶皱；岩层中裂缝发育、类型较多；生、储、盖层的岩石类型多、结构细；储层基质孔隙度低，成岩后生作用变化强烈，控制着有效储层的发育与分布；各气藏地层压力高，流体性质差异明显，具多裂缝系统；气田以背斜为中心，存在多种圈闭类型；气藏的形成有“褶前型”和“褶期型”两种模式。根据这些特征和模式，提出了复杂气田的勘探开发原则与相应的技术措施，以供勘探开发同类气田时参考。     

东海盆地X凹陷烃源岩生烃特征

采用有机岩石学和有机地球化学相结合的方法，系统研究了东海盆地Ｘ凹陷下第三系烃源岩生烃母质、原油化学组成与油源、有机质热演化与生烃模式，该区烃源岩（煤和泥岩）富含树脂体（全岩平均含量达４％，相对含量占１５％￣５０％），且树脂体含量与烃源岩总烃含量呈密切的正相关性。     

Using reduced data sets ISCCP-B2 from the Meteosat satellites to assess surface solar irradiance

This paper explores the capabilities of a combination of the reduced data set ISCCP-B2 from the Meteosat satellites and the recently developed method Heliosat-2 to assess the daily mean of the surface solar irradiance at any geographical site in Europe and Africa. Firstly, we discuss the implementation of the method Heliosat-2. Secondly, B2-derived irradiances are compared to coincident measurements made in meteorological networks for 90 stations from 1994 to 1997. Bias is less than 1 W m⁻² for the whole set. Larger bias may be observed at individual sites, ranging from −15 to +32 W m⁻². For the whole set, the root mean square difference is 35 W m⁻² (17%) for daily mean irradiance and 25 W m⁻² (12%) for monthly mean irradiance. These accuracies are close to those of similar data sets of irradiance, such as Medias and NASA Surface Radiation Budget. It is concluded that B2 data can be used in a reliable way to produce long-term time-series of irradiance for Europe, Africa and the Atlantic Ocean.     

��������DST�����ƹ����弰����̽��

根据四川东部气田井身及产层的特殊情况，通过大量的分析研究，从试油工艺角度出发，提出了川东气田推广ＤＳＴ测试的可行性，推广意义及技术措施，提出的用钻杆容积法配合ＤＳＴ测试，可计算因主、高产、高含硫化氢无地面求产条件时的气、水产量，提高了ＤＳＴ测试的成功率。     

Improving fertilizer recommendations for subsistance farmers in West Africa: The use of agro-economic analysis of on-farm trials

A large number of zero, half and full rate fertilizer trials were conducted on-farm in Southern Senegal with rainfed lowland rice (n = 24), maize (n = 48), and groundnuts (n = 18). Trial sites were located according to farmer selected criteria: soil texture in the case of rice; compound garden versus outer field in the case of maize; and, previous cropping history in the case of groundnuts. Quadratic fertilizer response curves using all the cases explained only 16–29% of the variance. Subsequent stratification of the fields by soil organic matter, texture, and pH permitted the identification of fertilizer responsive and non-responsive fields. Response curves using only the tests conducted on soils without a limiting constraint explained 36 to 47% of the variance. At half rate fertilization levels VCR's of 3.8 (maize), 5.8 (rice) and 6.9 (groundnuts) resulted. Within productive fields, level of weed control, percent barrenness and final stand at harvest explained much of the remaining variation in yields for rice (82%), maize (61%) and groundnuts (76%) respectively. Response curves were then used in an economic analysis to address on-farm fertilizer allocation issues. Based on survey results and field trial data, partial budgets for small and medium-sized farms were developed. This analysis showed marginal rates of return of 400 and 165 percent to half and full rate fertilization, respectively. This type of fertilizer validation program, conducted on farmer-selected sites, improved targeting of recommendations, and helped to identify agronomic practices that should result in reduced economic risk and increased fertilizer adoption by farmers.Research for this paper was conducted at the Institut Senegalais de Recherches Agricoles, and was supported by USAID Projects No. 685–0223 and No. 685–0205.