基于Copula函数我国林业经济发展与气候之间的关系研究

我国林业经济在国民经济发展中有着重要的地位,森林与气候之间也有着密切的关系。通过历史数据基于Copula函数模型验证林业经济发展与气温、降水量、湿度与日照数等气候因素之间的相关关系,林业生产总值与气温正相关,与湿度、日照数负相关。当我们认识到林业经济总产值与气温、降水量、湿度、日照数之间的相依关系和相依结构,就可以采取相应的措施。这将会对制定宏观经济发展规划与森林资源开发战略,具有一定的指导与实践意义。     

战略型“订单粮食”模式探讨

订单粮食作为一种新型的实现粮食产销衔接的经营方式,正受到越来越多的重视,但实施中却存在履约率太低的问题,步履艰难。为从根本上解决此问题,提出战略型订单粮食模式,即以建设中国式农场为主,以营造订单氛围为辅,努力将种粮大户和散户吸纳到粮食产业化经营体系下,开辟中国的农场时代。     

Growth is (really) good for the (really) rich

This paper analyses the relationship between mean income and the income of the rich. Our methodology closely follows that of Dollar and Kraay (Journal of Economic Growth, 2002, 7, 195), but instead of looking at the bottom of the distribution, we focus on the top. We use panel data from the World Top Incomes database, which collects top income data from several countries using tax returns as the raw source. We define the “rich” as earners in the top 10%, 1%, 0.1% and 0.01% of the income distribution. Using data since 1980, we find that economic growth is good for the rich in the sense that the mean income of the top decile of the distribution grows in the same proportion as that of the whole population. However, we also find that the income of earners in the top percentile of the distribution and above grows faster than average income: therefore, economic growth is really good for the really rich. We also find that during economic downturns the average income of top earners responds proportionally less to changes in mean income than during economic expansions. Our results are consistent with the increase in inequality that has been recently observed at the top part of the distribution in many countries, and they are robust to different specifications, country samples and time observations.     

基于GRA&BPNN的广西粮食产量预测研究

[目的]研究粮食产量的影响因素并以其相关性为基础预测粮食产量对实现广西粮食产业的"做强做优"具有重大意义。通常情况下粮食产量与种植技术发展水平、农田耕地面积、土地肥力、气候等诸多因素相关,但是在样本数据不足、数据间关联度不明显的情况下则无法采用回归分析、灰系统等常用预测方法。[方法]文章应用灰色关联分析方法得到水库水量、农田有效灌溉面积、第一产业从业人口、播种面积、除涝面积等5个与广西粮食产量关系最为密切的因子变量,同时取2004~2012年的数据作为学习、训练样本,以2013~2014年的数据为试报样本,并以此建立BP神经网络粮食预测模型。[结果]检验结果表明运用本模型预测粮食产量具有较高的精度和良好的泛化性。[结论]根据模型结果,该文提出提升广西粮食产业发展的可行性建议,即加强水库的管理、引导与粮食产业相关的产业、稳定粮食种植面积、加强洪涝灾害的防御和治理能力、推进农业信息化。     

呼伦贝尔草原生态功能区土地利用变化及驱动力分析

[目的]土地利用作为地球表面与人类活动连接的纽带,明确其变化特征及驱动力对于土地利用格局的优化、区域生态环境的改善和土地利用率的提高等具有重要的指导意义。[方法]文章以呼伦贝尔草原生态功能区为例,从土地利用动态度和土地利用转移矩阵来探究研究区在1990—2015年土地利用变化特征。在此基础上,运用主成分分析对研究区土地利用的年际变化进行驱动力分析。[结果]2015年草地面积为329.52万hm~2,占总面积的81.17%,是呼伦贝尔草原生态功能区的主体土地利用类型, 1990—2015年草地总量略有减少,减幅为0.04%;湿地作为研究区第二大土地利用类型,呈现先减后增、整体减少的趋势,整体减幅为0.36%;其他土地面积减少1.39万hm~2,减幅为19.05%;面积增加的土地利用类型中,耕地面积整体上呈现增加趋势,增加8 480hm~2,增幅高达102.60%;人工表面面积增加6 075hm~2,增幅为29.47%;林地面积增加了2 908hm~2,增幅10.48%。草地、湿地和其他土地利用类型表现为净转入特征,耕地、林地和人工表面用地表现为净转出特征。区域经济和农畜因素是研究区土地利用变化的主要驱动力。[结论]草地与其他土地利用类型间的相互转换是呼伦贝尔草原生态功能区土地利用变化的主要特征,区域经济和农畜因素共同影响研究区不同土地利用类型的分布。     

Rural Income Poverty in Western China Is Water Poverty

I. IntroductionThe elimination of poverty lies at the heart of development economics, and providesthe main justification for policies of promoting economic growth and development allover the world. Although arduous efforts have been devoted to poverty reductionworldwide, about 1.2 of 6 billion live on less than $1 a day (World Bank, 2002). AlthoughChina has reduced its poor population from 250 million in 1978 to 30 million in 2003, anoverall reduction in world poverty still depends on progre…     

Nondiscretionary residential water use: the impact of habits and water‐efficient technologies

Several studies published in the last few decades have demonstrated a low price‐elasticity for residential water use. In particular, it has been shown that there is a quantity of water demanded that remains constant regardless of prices and other economic factors. In this research, we characterise residential water demand based on a Stone‐Geary utility function. This specification is not only theory‐compatible but can also explicitly model a minimum level of consumption not dependent on prices or income. This is described as minimum threshold or nondiscretionary water use. Additionally, the Stone‐Geary framework is used to model the subsistence level of water consumption that is dependent on the temporal evolution of consumer habits and stock of physical capital. The main aim of this study is to analyse the impact of water‐saving habits and water‐efficient technologies on residential water demand, while additionally focusing attention on nondiscretionary uses. This is informed by an empirical application using data from a survey conducted among residents of Brisbane City Council, Australia. The results will be especially useful in the design of water tariffs and other water‐saving policies.     

我国海洋优势产业筛选及发展对策研究

海洋经济发展成为日益关注焦点。运用模糊评价法对我国海洋优势产业进行筛选,分别筛选出我国传统海洋优势产业、战略性新兴海洋优势产业、潜在海洋优势产业和总体海洋优势产业。综合各优势产业分析结果,鉴于具体海洋产业优势产业地位的重叠性,因此对海洋渔业、海洋交通运输业、滨海旅游业、海洋油气业、海洋工程建筑业和海洋化工业的发展提出具体对策。     

经济增长与经济利益关系的演变

关于“经济增长与收入分配”这一重要的经济学理论命题存在着“替代论”与“互补论”的争论，而这一争论的实质又在于阐述经济增长与经济利益关系演变之间的关系。经济增长是经济利益关系演变的物质基础和前提条件，经济增长通过影响经济利益的总量，以及参与经济利益总量生产的要素报酬变化这一机制影响到经济利益关系的演变。经济增长影响经济利益关系改善受到经济增长水平、状态等因素的制约。在不同的经济增长方式、经济增长波动、经济增长阶段下，经济利益关系格局都表现出不同的特点。经济利益关系的变化也会对经济增长产生反馈效应。     

“五结合”生态温室生命周期评价及比较分析

[目的]通过"五结合"生态温室生命周期评价及比较分析,发现各类温室潜在的环境影响及其关键要素,探索各模式改进提升的重点及未来发展方向。[方法]应用生命周期评价方法,将"五结合"生态温室与国内典型地区节能日光温室和国外同类模式进行环境综合评价,在此基础上分析"五结合"生态温室替代常规模式的可能性。[结果]较节能日光温室,生态温室单位产品的能源消耗、水资源消耗、气候变化、潜在的环境酸化、富营养化、人体、水体和土壤毒性分别降低了27%, 64%, 27%, 32%, 43%, 97%, 99%和99%,综合环境指数降低98.6%,环境效益大幅度提升。与国外同类模式相比,由于充分利用太阳能,中国常规模式在降低能源消耗和温室气体减排方面优势明显,其他各项环境指数与国外相比还存在较大差距,但"五结合"生态温室各项指数全面优于或接近国外同类模式。[结论]以"五结合"生态温室为代表的生态模式能够解决国内外温室发展面临的众多瓶颈问题,具有极大的发展潜力和应用价值。