CDIO在“1+2+1”专业综合改革中的教学实践探讨

文章以矿山机械专业综合改革为契机,结合矿山机械专业四个学年的课程设置,提出了CDIO模式在不同学年针对所开课程的教学实践,并将智能化设计融入到CDIO模式的教学实践中。     

No place like home? Availability,opportunity, and substance use in adolescence

Surveys on drugs and alcohol availability show that (1) alcohol is much more easily accessible than both cannabis and tobacco, and that (2) many adolescents still do not find it ‘easy’ to access those substances. In the current study, we examine the importance of both opportunity and availability in assessing substance use in adolescence. Our measures of opportunity include skipping school and unstructured socializing, while availability measures include parental substance use and perceived availability of tobacco, alcohol, and cannabis at home. We draw from two waves of the National Longitudinal Study of Adolescent to Adult Health (Add Health) survey, and distinguish between (a) predictors of Wave II substance use for the whole sample, and (b) predictors of Wave II initiation for those respondents who reported no use at Wave I. We find that availability at home and parental substance use is correlated with substance-specific current adolescent consumption, but these indicators are not associated with initiation behavior. Instead, initiation seems to be carried by unstructured socializing outside of the home, with availability at home acting as reinforcement once some level of substance use is established.     

土壤水分对烤烟生长和光合作用的影响

两烤烟品种NC82和K326在伸根期、旺长期和成熟期分别以不同的土壤含水量进行处理。结果表明：干旱和淹水使茎高、叶面积生长速率降优；水分过多、过少均使净光合速率（Pn）下降，Pn／P总（总光合速率）、Pr（光呼吸）／P总下降，Dr（暗呼吸）／P总和蒸腾系数则增加。适宜于烤烟伸根、旺长和成熟初期生长和光合作用的土壤相对持水量分别为60％、80％和70％。     

An Enforceable Indoor Air Quality Standard for Environmental Tobacco Smoke in the Workplace1

Environmental tobacco smoke (ETS)has recently been determined by U.S. environmental and occupational health authorities to be a human carcinogen. We develop a model which permits using atmospheric nicotine measurements to estimate nonsmokers’ETS lung cancer risks in individual workplaces for the first time. We estimate that during the 1980s, the U.S. nonsmoking adult population's median nicotine lung exposure (homes and workplaces combined)was 143 micrograms (μg)of nicotine daily, and that most-exposed adult nonsmokers inhaled 1430 μg/day. These exposure estimates are validated by pharmacokinetic modeling which yields the corresponding steady-state dose of the nicotine metabolite, cotinine. For U.S. adult nonsmokers of working age, we estimate median cotinine values of about 1.0 nanogram per milliliter (ng/ml)in plasma, and 6.2 ng/ml in urine; for most-exposed nonsmokers, we estimate cotinine concentrations of about 10 ng/ml in plasma and 62 ng/ml in urine. These values are consistent to within 15% of the cotinine values observed in contemporaneous clinical epidemiological studies. Corresponding median risk from ETS exposure in U.S. nonsmokers during the 1980s is estimated at about two lung cancer deaths (LCDs)per 1000 at risk, and for most-exposed nonsmokers, about two LCDs per 100. Risks abroad appear similar. Modeling of the lung cancer mortality risk from passive smoking suggests that de minimis [i.e., “acceptable” (10^-6)], risk occurs at an 8-hr time-weighted-average exposure concentration of 7.5 nanograms of ETS nicotine per cubic meter of workplace air for a working lifetime of 40 years. This model is based upon a linear exposure-response relationship validated by physical, clinical, and epidemiological data. From available data, it appears that workplaces without effective smoking policies considerably exceed this de minimis risk standard. For a substantial fraction of the 59 million nonsmoking workers in the U.S., current workplace exposure to ETS also appears to pose risks exceeding the de manifestos risk level above which carcinogens are strictly regulated by the federal government.     

Tobacco control and smoking cessation efforts in an inner-city African American community

This paper describes the conceptual framework that guided the development and implementation of a large-scale, community-based health initiative to lower the prevalence of smoking in an urban African American community. This project developed culturally-sensitive approaches to reducing smoking in the community and to promoting tobacco control efforts developed and implemented by community members. A randomized clinical-trial methodology was used to test the efficacy of the culturally-sensitive, community-developed smoking cessation interventions in lowering smoking rates as compared with a self-help approach. Two theoretical models guided the intervention strategies: a macro-level model applicable to the community as a whole, and a psychological process model applicable to individuals. The community model was based on community systems theory and incorporated the Readiness for Change Model, which was applied in both the individual and organizational models. In addition, culturally-sensitive data collection methods were developed to improve the reliability and validity of project data, especially in determining the smoking prevalence rates and smoking behaviors of hard-to-reach, inner-city African Americans. Since the health of individuals is related to the health of their communities, smoking cessation and tobacco control activities that are integrated into the framework of the community (i.e., churches, city-council, housing developments, community organizations), and incorporate culturally-relevant and specific interventions can be effective methods for achieving behavioral and societal change.     

烟草品牌战略管理浅析

品牌是核心价值的体现,是企业核心竞争力的体现,实施品牌战略,加强战略管理,是企业实现可持续性发展的重要手段。本文通过分析烟草行业在品牌管理中存在的一些误区,结合有关品牌战略和品牌管理的已有理论研究成果,提出了烟草行业强化品牌管理、构建品牌战略可采用的策略及在实际操作中的建议。     

我国草牧业推进现状、问题及政策建议——基于山西、青海草牧业试点典型区域的调研

在对山西和青海草牧业发展典型试点区域实地调研的基础上,从草食畜牧业发展、“粮+经+饲”种植结构优化、牧草种植品种区域差异化及“粮改饲”比较效益等方面分析草牧业推进现状;对各试点区草牧业发展在科技推广、生产经营模式发展、融资平台建设、牧草青贮方式选择、牧草种植与精准扶贫融合、龙头企业带动等方面的经验进行总结;剖析草牧业发展中仍存在的传统种养观念盛行、牧草作业机械及配套设施保有量不足、发展技术制约明显、牧草生产高风险但没有建立政策性保险、金融扶持发展机制不到位等难点与突出问题。针对难点与突出问题提出切实做好宣传及科技推广培训工作、加快研发可以适应不同区域生产的牧草机械设备、全力促进草畜紧密结合、推进多样化牧草产业发展形式、推动牧草产业保险实施及加大金融支持力度等政策建议。     

规模农户病虫害防治机械投资及其效应

利用江苏省水稻产业体系对规模种植户的调研数据,使用Heckman样本选择模型,从作业质量风险认知和作业及时性风险认知角度出发分析病虫害防治环节影响规模种植户机械投资和投资水平的原因,并进行稳健性检验,在此基础上分析投资机械自给服务对农户农业产出的影响。研究发现：规模种植户是否进行机械投资以及投资水平不仅受外包服务作业质量风险认知的影响,农户对于外包服务作业的及时性风险认知也是影响其机械投资的关键,并且农户的风险规避程度在风险认知影响病虫害防治机械投资决策之间具有显著的调节作用。进一步分析发现,规模农户投资病虫害机械自我防治可以显著提升农业产出水平。     

农机服务对小农户土地流转“内卷化”的影响

农机服务的快速发展能否解释农地流转并未推动我国农业适度规模经营趋势而出现的“内卷化”现象,仍有待分析与验证。采用中国农村家庭大数据库（CRHPS）中的小农户样本,分析小农户在土地流转市场中的处境并运用三阶段最小二乘法和中介效应模型实证检验农机服务对其土地流转决策的影响。结果表明,小农户采用农机服务显著地降低了土地转出并增加了土地转入,并验证了包括农业劳动力投入、农业技术应用和农业收入在内的三个主要影响机制。研究论证了农机服务能够在一定程度上解释我国土地流转中参与率增速放缓、小规模转入与部分转出对应的小农户复制以及农地流转对农业生产率作用递减的“内卷化”现象。提出在制定完善农机服务政策时,既要满足小规模农户的生产需求以维持家庭生计,又要衔接土地转入户的服务需求以推动土地适度规模经营。     

资产专用性、不确定性与水稻种植模式选择

从资产专用性与不确定性视角,运用二元Logistic模型实证分析了水稻种植模式选择的影响因素。研究结果表明：资产专用性与不确定性对水稻种植模式选择的影响,部分通过显著性检验;家庭中50岁以上务农劳动力越多、村庄交通条件越好,农户选择种植两季水稻的概率越低;务农劳动力兼业、拥有整地机械、灌溉条件越好,农户选择种植两季水稻的可能性更大,其中务农劳动力通过兼业使劳动时间错峰配置实现劳动力最优利用,最终使农户倾向于种植两季水稻。水田面积与稻农选择两季水稻种植模式呈现倒U型的关系;家庭务农劳动力人数、农业收入占比等控制变量对农户水稻种植模式选择的影响显著。政府应继续培育新型农业经营主体,发展适度规模经营,加大农机补贴力度,提高社会化服务水平,应对农业劳动力不足与弱质化的问题,提高农户种植两季水稻的积极性。