城市化对居民液态奶消费的影响——基于农民工的视角

为探究城市化对居民液态奶消费的影响,从农民工消费角度出发,基于2014年在我国5省调研得到的截面数据,采用Heckman两步法分析城市化影响液态奶消费的途径。结果表明:城市化进程下,居民收入、市场发育程度、居民消费习惯对液态奶消费增长的贡献依次增大,在经济较发达的地区,消费习惯的贡献更加明显,在经济较不发达的地区,收入和市场发育程度的贡献相对突出;消费选择是影响液态奶平均消费水平的关键,而且相比于农村居民,农民工的消费习惯正在接近城市居民。根据分析结果,做出了液态奶消费增长预测,建议以培养消费习惯、缩小城乡差距、提高农民工保障水平作为促进居民液态奶消费的重要途径。     

荒草地红火蚁工蚁活动性程度研究

应用刻度图示法研究了荒草地红火蚁Solenopsis invicta工蚁群体活动性规律.结果表明,最高爬升高度、平均爬升高度、工蚁恢复平静时间与蚁巢体积大小无显著相关;不同蚁巢被干扰后标尺上工蚁数量随干扰时间的延长,先快速增加,45～60 s时达到最大,随后缓慢减少直至标尺上无工蚁.通过分析建立了红火蚁工蚁平均数量与干扰时间关系的多个模型.提出了红火蚁工蚁活动性综合评价指标:工蚁活动性评价指标=工蚁累计数量×0.4 工蚁最高爬升高度×0.1 工蚁平均爬升高度×0.3 工蚁恢复平静时间×0.2.     

医疗保险对农民工留城定居意愿的影响——以江苏省南京市为例

根据2013年对江苏省南京市农民工的调查,运用Probit模型分析影响农民工留城定居意愿的决定因素,重点考察社会保障中医疗保险对其留城定居意愿的影响程度。结果表明,新农合由于异地报销困难等原因对农业转移人口留居城市的意愿有负向影响,城居保、城职保对农业转移人口留居城市有正向影响,但是由于农业转移人口的就业特征与流动性特点,以及社会保障制度设计等原因,农业转移人口的医疗保险以参加新农合为主。     

我国农民工数量与农村居民家庭收入关系的实证研究

根据1978年来的时间序列数据,检验了我国农民工数量与我国农村家庭主要收入、农村居民生活水平的关系,结果显示：农民工与我国农村家庭生活水平存在紧密的正向关系,农民工的增多促进了农村居民的生活水平的提高;农民工的增多并不会导致农村家庭经营收入的减少;农民工数量增多的原因与农村居民的人均工资性收入和家庭经营收入之间的差额存在显著关系;农村边际劳动力要素机会成本是影响农民工数量增多的比较重要原因;家庭经营收入和进城务工收入的总和是影响农民工数量变化的重要原因.     

试论农民工的城市社区支持对策

针对社区忽视为农民工服务的现象,提出应该从以下5个方面做好对农民工的服务工作：引导社区公众消除歧视和偏见;提供法律法规方面的服务;积极开展各种形式的就业服务;担当社区日常生活向导;举办丰富多彩的社区文化活动。     

A risk assessment of atrazine use in California: human health and ecological aspects

A risk assessment of the triazine herbicide atrazine has been conducted by first analyzing the toxicity database and subsequently estimating exposure. Margins of safety (MOS) were then calculated. Toxicity was assessed in animal studies and exposure was estimated from occupational and dietary sources. In acute toxicity studies, atrazine caused developmental toxicity in the rabbit [no observed effect level (NOEL) 5 mg kg(-1) day(-1)] and cardiotoxicity in a dog chronic study (NOEL 0.5 mg kg(-1) day(-1)); cancer (mammary glands) resulted from lifetime exposure. The mammary tumors, which occurred specifically in female Sprague-Dawley rats, were malignant, increased in a dose-dependent manner and were also observed with other, related triazines. Evidence for a genotoxic basis for these tumors was either equivocal or negative. Triazines have been shown to be clastogenic in Chinese hamster ovary cells, in vitro, but without showing a convincing dose/response relationship. Atrazine can be converted into genotoxic N-nitrosoatrazine in the environment or the digestive system, suggesting that N-nitrosamines derived from triazines could be oncogenic. However, it was concluded that N-nitrosotriazines are unlikely to play a significant role in triazine-induced rat mammary gland tumors. An endocrine basis for the mammary tumors, involving premature aging of the female SD rat reproductive system, has been proposed. A suppression of the luteinizing hormone surge during the estrus cycle by atrazine leads to the maintenance of elevated blood levels of 17beta-estradiol (E2) and prolactin. The mechanism for tumor development may include one or more of the following: the induction of aromatase (CYP19) and/or other P450 oxygenases, an antagonist action at the estrogen feedback receptor in the hypothalamus, an agonist action at the mammary gland estrogen receptor or an effect on adrenergic neurons in the hypothalamic-pituitary pathway. None of these has been excluded as a target because there has been a lack of a rigorous attempt to address the mechanism of action for mammary tumors at the molecular level. The potential occupational exposure to atrazine was assessed during mixing, loading and application. Absorbed daily dosage values were 1.8-6.1 microg kg(-1) day(-1). The MOS values (animal NOEL/human exposure) for short-term (acute) exposure were 820-2800. Longer-term occupational exposure and risk were also calculated. Detectable crop residues are generally absent at harvest. Theoretical calculations of acute dietary exposure used tolerance levels, along with secondary residues, and water, for which there is a maximum contamination level; atrazine plus the three main chlorotriazine metabolites were combined. MOS values were above 2000 for all population subgroups. Dietary exposure to atrazine is therefore extremely unlikely to result in human health hazard. Recent publications have reported a possible feminization of frogs, measured in laboratory and field studies. This is assumed to be due to the induction of aromatase, but no measurements of enzyme activity have been reported. In field studies, the water bodies with the greatest numbers of deformed frogs sometimes had the lowest concentrations of atrazine. Other studies have also cast doubt on the feminization theory, except perhaps at very high levels of atrazine. Epidemiology studies have investigated the possibility that atrazine may result in adverse effects in humans. Although some studies have claimed that atrazine exposure results in an elevated risk of prostate cancer, the published literature is inconclusive with respect to cancer incidence.     

新农村建设的新视角:发展"农民工经济"

将农民工从农民中分划出来,将农民工视为一个特别群体,并以此为支点分析其在破解三农问题中的核心作用。认为“农民工经济”应当包括外出打工经济与回乡创业经济两个部分,而发展“农民工经济”的关键就是在二者中找到一个平衡点,通过发展农民工经济推动农村经济的发展与农村剩余劳动力的转移,进而从建设社会主义新农村找到一个新视角。     

职业发展视角下新生代农民工归属感问题研究

介绍了新生代农民工归属感问题的解决关键在于"现代职业"的培养,应从职业发展视角出发,主张政府、企业、社会各尽其责,从而实现现代职业期望,使新生代农民工能够从处于双向边缘化位置转变为拥有双向选择权的主动位置。     

农民工定居转移的影响因素

在对农民工迁居城市的影响因素和农民工放弃永久性迁居城市的解释进行综述,把定居方式选择（migration）作为因变量,把性别（sex）、年龄（age）、相对月总收入（income）、教育程度（edu）、工作经验（exp）、社会关系（relation）、社会保险（security）设定为自变量,采用2009中国农业大学国家大学生创新性实验计划调查所得的数据,利用Logistic二元选择模型构建相关的计量经济模型测算各影响因素对定居方式选择的影响程度。结果表明,教育水平、个人能力、社会关系与社会保障是决定农民工举家永久迁居城市的主要影响因素,人力资本与社会保障对于提高农民工收入、改善其生活质量具有重要意义。     

青年铁路职工在志愿行动中树立社会主义核心价值观

青年职工是铁路的未来和希望，是铁路生产运输的生力军和突击队、是一个铁路长期发展的根本。近几年，铁路青年职工越来越多，做好青工的思想工作，提高青工的素质，树立社会主义核心价值观，对于进一步推进铁路改革实现持续有效和谐发展具有十分重要的意义。