天然气产量季节预测模型的比较与选择

随着气田企业规模的扩大和竞争的加剧,需要建立一套完整的短期天然气产量预测方法及模型,以预测未来的产量发展趋势,故提出三种基于时间序列预测模型:布朗指数平滑法(Smooth)、季节系数法时间序列的预测、用于时间序列的灰色系统预测方法.但是普通时间序列预测模型的参数难以估计并且模型较难预测具有季节特征的时间序列问题,根据天然气产量的季节性、周期性特点,实验结果表明:季节系数法时间序列的预测能够对带有季节特征的历史数据进行有效预测,对进行气田企业的安全生产都具有一定的理论和实践价值.     

模糊条件下方案净现值的统计分析

研究模糊条件下利用模糊统计分析方法选择评价方案,首先介绍了模糊数、模糊统计分析指标的运算及其排序规则,然后根据模糊条件下方案的类型,探讨了模糊统计分析方法如何应用于方案的选择,最后利用数值案例展示了模糊统计分析方法在方案选择中的应用.该研究为模糊条件下的方案选择提供了一种理论工具.     

The Methuselah Effect: The Pernicious Impact of Unreported Deaths on Old-Age Mortality Estimates

We examine inferences about old-age mortality that arise when researchers use survey data matched to death records. We show that even small rates of failure to match respondents can lead to substantial bias in the measurement of mortality rates at older ages. This type of measurement error is consequential for three strands in the demographic literature: (1) the deceleration in mortality rates at old ages; (2) the black-white mortality crossover; and (3) the relatively low rate of old-age mortality among Hispanics, often called the “Hispanic paradox.” Using the National Longitudinal Survey of Older Men matched to death records in both the U.S. Vital Statistics system and the Social Security Death Index, we demonstrate that even small rates of missing mortality matching plausibly lead to an appearance of mortality deceleration when none exists and can generate a spurious black-white mortality crossover. We confirm these findings using data from the National Health Interview Survey matched to the U.S. Vital Statistics system, a data set known as the “gold standard” (Cowper et al. 2002) for estimating age-specific mortality. Moreover, with these data, we show that the Hispanic paradox is also plausibly explained by a similar undercount.     

农业转移人口就近城镇化意愿的地区差异

基于对中西部地区15个省市农业转移人口就近城镇化意愿的问卷调查数据,以社会认同度为研究视角,构建多群组结构方程模型分析中西部地区人口就近城镇化意愿的地区差异及其影响因素.研究结果表明:个人特征差异性对中西部不同地区人口就近城镇化意愿影响显著;中西部不同地区农业转移人口的社会认同度与其就近城镇化意愿显著正相关,且西部地区农业转移人口受到的影响作用更明显.东部地区农业转移人口更注重职业升迁机会、职业技能水平、子女教育状况、工资待遇水平、工作环境、工作时长的满意度.西部地区农业转移人口则更关注其与市民的关系、城市社会关系网络、户籍状况、基本公共服务、城市物价水平及居住条件的改善程度.     

Trends in bird species richness,abundance and biomass along a tropical urbanization gradient

Impacts of urbanization on biodiversity are commonly studied using urbanization gradients which provide a space-for-time substitution in estimating consequences of urban expansion. Rates of urbanization and human population growth are high in tropical countries of the developing world, which also hold most of the world’s biodiversity hot-spots, yet few studies have considered biodiversity trends along urban gradients in these regions. Bird communities across a gradient of nine sites in Uganda, from the city centre of Kampala to outlying rural locations, were studied over a six year period. These sites were ordered along an urbanization gradient using Principle Components Analysis based on habitat variables estimated at each site. Bird species richness showed a decrease from rural to urban sites, a trend especially evident in forest birds. There was no clear pattern in total abundance, total biomass or biomass per individual along the gradient. However, this latter result was heavily influenced by a colony of Marabou Storks at one site. When this species was omitted, there was evidence of a positive trend with urbanization, showing that as species richness decreased, the bird community was increasingly dominated by larger species with increasing urbanization, which were mainly scavengers able to exploit human refuse. These results provide further support for the negative impacts of urbanization on species richness, but also demonstrate trends in abundance and biomass are variable across different regions. In particular, the increasing dominance of larger species in urban areas may be relevant to certain geographic and/or socioeconomic contexts.     

Women’s attitudes towards the medicalization of childbirth and their associations with planned and actual modes of birth

Problem

Rates of medical interventions in childbirth have greatly increased in the Western world.

基于突发群体事件预防的高校网络舆情管理

高校的稳定对于社会的稳定具有重要意义。从国际和国内经验来看,移动互联网改变了高校的网络舆情环境,因而给突发群体事件的预防及高校的稳定带来了新的挑战。移动互联网下的高校网络舆情影响力、参与积极性、突发性及冲击力都大大提升,针对其进行的管理呈现有效处置周期更短、官方舆论引导能力更弱、管控复杂程度增加且容易出现群体极化行为等特点,高校应从组织管理体系、线下沟通机制、舆情信息处理机制、危机应急处理机制、网络舆情管理队伍、网络道德文化等多个方面进行综合治理,从而改善高校网络舆情管理,更好地预防突发群体事件的发生。     

邯郸成语典故的文化精神与当代价值

邯郸成语典故大量孕育于春秋战国至两汉时期,是其辉煌时代的一种特有的历史记忆形式,也是其注重事功的学术传统与全民皆商的土风民俗的必然产物。它蕴涵了变革图强、开放包容、厚德重法等主要文化精神,有着不容忽视的当代价值,并且可以通过与当代社会主义文化繁荣发展的密切结合来切实实现其当代价值转换。     

外商直接投资对中国高新技术产业国际竞争力的影响

基于国际贸易理论中外商直接投资对一国产业国际竞争立提升的理论,通过协整检验的计量方法具体分析了外商直接投资对中国高新技术产业总体国际竞争力及对中国主要出口的三种高新技术产品的国际竞争力的影响程度。结果表明,外商直接投资对中国计算机技术、通信技术和电子技术等三类高新技术产品出口竞争力有很强的正向作用。因此,继续吸引外商投资,可以较好的提升中国高新技术产业的国际竞争力。     

教育内部民主法制化简论

教育内部民主是相对于"保障教育权利平等"的外部民主而言的,包括教育过程中师生关系的民主和教育管理与决策的民主。因为缺乏必要的规范,教育内部民主在实践中常常表现为非理性的冲动,教育内部民主需要通过理性的法制介入得以合理有效地实现。教育内部民主法制化不仅是必要的也是可能的。