Assessing the Potential Impact of Avian Influenza on Poultry in West Africa: A Spatial Equilibrium Analysis

We analyse the potential economic impacts of avian influenza (AI) in Nigeria, using a spatial equilibrium simulation model. Depending on the size of the affected areas, the direct impact of the spread of AI along the two major migratory bird flyways would be a loss of about 4% of national chicken production. However, the indirect effect – consumers’ reluctance to consume poultry if AI is detected, causing a decline in chicken prices – is generally larger than the direct effect in our simulation. We estimate that Nigerian chicken production would fall by 21% and chicken farmers would lose US$250 million of revenue if the worst‐case scenario occurs. The negative impact would be unevenly distributed in the country, and some states and districts would be seriously affected. The study shows that, while most attention has focused on preventing a global influenza pandemic, preventive measures are also needed at the national, regional and local levels, because AI could potentially have a major negative impact on the poultry industry and the livelihood of smallholder farmers in many regions in West Africa.     

黄淮海区气候变化及其对冬小麦光温生产潜力的影响

气候变化对冬小麦生长发育及产量的影响、冬小麦生产对气候变化的适应已经成为学术界研究的热点问题之一。黄淮海区是我国第一大冬小麦主产区,研究选择黄淮海区为研究区域,首先运用线性倾向率方法分析了黄淮海区近50年来太阳辐射量和平均温度在全年和冬小麦生育期两个时段内的时间和空间变化特征,运用AEZ模型计算了黄淮海区各气象站点的冬小麦光温生产潜力;在此基础上,分析了太阳辐射量和温度变化对冬小麦光温生产潜力的影响。结果表明:(1)黄淮海区全年日均太阳辐射量和生育期内日均太阳辐射量均表现为减少的趋势,且全年日均太阳辐射量减少幅度较大;(2)黄淮海区年平均温度表现为上升的趋势,而冬小麦生育期内平均温度的上升趋势极不明显;(3)黄淮海区冬小麦生育期内太阳辐射量的减少和平均温度的降低是导致冬小麦光温生产潜力下降的主要原因。     

论我国森林资源的法律保护

森林资源是一种极为重要的自然资源,对于维持整个生态平衡、防止水土流失、预防自然灾害发生、改善气候等方面均发挥着极其重要的作用。从我国现行森林资源保护立法出发,分析森林资源保护法律体系中存在的问题,提出修改《森林法》以及相关法律的构想,以求通过完善立法,建立完备的森林资源法律保护体系,实现对森林资源的保护与可持续利用。     

国家森林公园年卡市场开发与营销策略——以福州国家森森公园为案例

查阅福州国家森林公园的各种历史资料,结合所收集的福州国家森林公园年卡调查的数据,对福州国家森林公园年卡市场开发做了可行性分析,明确了福州国家森林公园年卡市场定位,提出了年卡市场开发的策略和营销策略。     

福建省自然保护区与森林公园生态服务功能评价

应用Costanza提出的全球生态系统服务功能评价指标分析了福建省自然保护区与森林公园生态服务功能,并研究了福州国家森林公园森林生态系统固碳释氧功能及其价值估算,旨在为福建省自然保护区及森林公园的可持续发展提供背景资料和科学依据。     

耕地质量预警

研究目的:研究耕地质量预警的理论与方法,提供开展耕地质量的预警与消警依据。研究方法:文献资料法。研究结果:分析了耕地质量的重要性与波动性、耕地质量改良的滞后性与艰难性,指出了开展耕地质量预警研究的理论与实践意义,阐述了警情、警源、警兆和警度等基本内容,提出了耕地质量预警的方法与基本步骤。     

Not enough money or not enough time to satisfy the Thrifty Food Plan? A cost difference approach for estimating a money–time threshold

Food production at home requires money and time. Food assistance programs focus exclusively on the money cost, while ignoring the time cost. This one-dimensional focus could undermine the effectiveness of food assistance programs. In the spirit of Vickery (1977), this paper uses a cost difference approach to develop a money–time threshold, and several related metrics, to determine whether money or time is the most limiting resource in reaching the Thrifty Food Plan (TFP) target. In our empirical analysis we find that when time is ignored, single headed households spend on average 35% more than required to meet the TFP target. However, when time is included, these households spend on average 40% less than required to meet the TFP target. In addition, we find that when time is ignored, 62% of single headed households on average spend enough money to reach the TFP target, but when time is included, only 13% of single headed households spend enough on average to reach the TFP target. Our empirical results suggest that time is more constraining than money in reaching the TFP target. These results imply that metrics solely focusing on money could severely underestimate the gap between actual expenditures and those required to reach the TFP target.     

乐山旅游新去处 乌木珍品文化博物馆

四川乐山乌木珍品文化博物苑是一座集乌木雕刻艺术的收藏、研究、展示为一体的专题性博物馆。乌木博物苑位于世界自然与文化双遗产——乐山大佛、峨眉山绿色旅游通道上,主要由乌木博物馆和毛主席像章陈列馆两部分组成。     

日本新修普惠制方案对我国出口影响实证分析

普惠制(GSP)是由“七十七国集团”在1964年第一届联合国贸发会议上正式提出，1971年关贸总协定成员国正式确定的发达国家给予发展中国家的普遍优惠待遇，它为发展中国家生产的符合要求的产品提供了进入发达国家市场的优惠——减少或免除税收，是发达国家给予发展中国家的一种普遍的、非歧视的和非互惠的关税优惠制度。     

C/C++语言指针教学研究

本文通过分析系统为普通变量和指针变量所分配的存储空间的地址特点,从另一个角度深刻揭示指针的实质,给出了在C/C++语言教学过程中如何将指针的概念具体化的几种方法.