我国人口资源环境与经济的可持续发展

为了保持经济又好又快的发展,应该正确处理人口、资源、环境与经济的关系;必须长期坚持计划生育的基本国策,控制人口增长的数量,提高人口的质量,减轻过多的人口对资源和环境的压力;提高自主创新能力,转变经济增长方式,发展循环经济,节能减排,建设资源节约型、环境友好型社会,走新型工业化道路,实现可持续发展战略。     

On the forecasting of the challenging world future scenarios

Logistic and power law methodologies for both retrospective and prospective analyses of extended time series describing evolutionary growth processes, in environments with finite resources, are confronted. While power laws may eventually apply only to the early stages of said growth process, the Allee logistic model seems applicable over the entire span of a long range process. On applying the Allee logistic model to both the world population and the world gross domestic product time series, from 1 to 2008 AD, a projection was obtained that along the next few decades the world should experience a new economic boom phase with the world GDP peaking around the year 2020 and proceeding from then on towards a saturation value of about 142 trillion international dollars, while the world population should reach 8.9 billion people by 2050. These results were then used to forecast the behavior of the supply and consumption of energy and food, two of the main commodities that drive the world system. Our findings suggest that unless the currently prevailing focus on economic growth is changed into that of sustainable prosperity, human society may run into a period of serious economical and social struggles with unpredictable political consequences.     

河南省粮田人口承载力影响因素的实证分析

对土地人口承载力理论的国内外研究现状进行了综述;结合前人的研究成果,选取相应指标,在协整分析的基础上,运用多元线性回归方法对河南省粮田人口承载力的影响因素进行了实证分析。结果显示:人口因素、农业劳动力生产技术水平因素和土地因素与粮田人口承载力正相关,其中人口因素的影响最大;粮食需求因素与粮田人口承载力负相关。最后提出提高河南省粮田人口承载力的政策建议。     

PH值对水库中藻类生长影响研究

本文主要探讨了在水库水藻类"水华"现象中pH值的变化,发现水体pH值于藻类数量之间存在较好的相关性,并在pH值与藻种群密度D之间尝试性建立数学模型.同时发现△pH与藻类的生命活性之间也存在较好的相关性,在藻类的对数生长期内△pH达到最大值.可以通过△ApH的观测了解藻类的生长态势,并作出相应预测.     

中国流动人口与城镇化、工业化发展关系的实证分析

伴随着经济的不断发展,我国流动人口数量快速增加,流动人口管理已成为国家关注的热点.进行流动人口与城镇化、工业化发展关系的实证量化分析,对流动人口管理具有积极的意义.对流动人口率、城镇化率和工业化率之问数量变动分析得出,虽然三者表现为正线性相关,但由于他们都为非平稳序列,不宜展开线性关系的进一步的分析;格兰杰因果分析发现,仅存在城镇化率对流动人口的单向影响关系,同时也仅存在流动人口对工业化率的单向影响关系.     

流动人口与常住居民计生服务均等化评价与需求偏好差异——基于绍兴市的个案研究

对绍兴市的流动人口和常住居民两个群体享有的计划生育公共服务的均等化水平进行了评价和分析。总体上流动人口与常住居民之间的计生服务均等化程度处于较高水平,但婚姻状况等等一些个人特征因素不同程度地影响着流动人口对计生服务均等化的感受和评价。流动人口与常住居民对计生服务的内容存在较大的需求偏好差异。     

模拟月壤在不同堆积状态下的紧实度研究

月球表面覆盖着一层细颗粒粉末状的松散月壤,这必将对月球探测车辆的行驶性能带来影响。研究用于月面力学试验的模拟月壤紧实度,对保证月球探测车辆的正常工作具有重要意义。圆锥指数和容重都可以表征模拟月壤的紧实度,通过不同的分析方法对模拟月壤进行整备,从而得出模拟月壤在不同堆积状态下圆锥指数和容重的变化规律,并且将其结果与真实月壤进行比较,其结果为月球车内场试验提供了标准和依据。     

北京市户口逐步开放条件分析

北京作为我国的首都,政治、文化中心,其人口数量与日俱增,而流动人口的大规模的增加是北京常住人口快速增加的主动力,传统的户籍限制存在的弊端日益凸显,本文认为户籍制度改革向流动人口倾斜具有一定必要性和可能性,并提出首先逐步向河北天津籍流动人口开放,以缓解北京人口压力,同时保证2015年后劳动力的供给。     

郑州市少数民族流动人口就业问题浅析

城市化进程让更多少数民族流动人口到城市就业。本文从郑州市少数民族流动人口的就业现状出发,分析了少数民族流动人口就业存在的问题,并就与之相关的对策进行了探讨。     

Shifting cultivation and forest pressure in Cameroon

Shifting cultivation is often blamed as a principal cause of deforestation in tropical Africa. It is claimed that the practice is unsustainable because shortened fallow lengths result in soils too degraded to support forest vegetation. The decline in fallow lengths is often attributed to increases in population density and greater market participation. The conventional wisdom makes several claims that are as yet unsubstantiated. This article investigates whether there is evidence to support two of these claims in southern Cameroon. First, using both cross‐sectional and panel data, I find that there is indeed a robust negative association between fallow lengths and population density in the study area and weaker evidence for a negative relationship between fallow lengths and market participation. Second, a stochastic frontier production function approach is used to investigate the marginal contribution of fallow to output. Results indicate that fallow lengths are not low enough to be affecting yields and therefore do not appear to be resulting in declines in soil fertility. Thus overall, while some of the assumptions of the conventional wisdom appear to be true, there is little evidence to support its dramatic conclusion that shifting cultivators are causing deforestation in the forested region of Cameroon.