泥土中植物花粉的提取与检验

目的建立泥土中植物花粉的提取和检验方法。方法用去二甲苯、18%盐酸溶液处理提取泥土中的花粉 ,然后用扫描电镜进行检验。结果从不同的泥土中检出不同花粉。结论本方法能有效分离提取泥土中花粉。对其它混合物中花粉的提取有参考价值。本文介绍一种泥土中花粉提取的简捷方法 ,以及利用扫描电镜 /能谱仪对提取的植物花粉进行检验的方法。     

仔猪睾丸组织体外培养方法的建立

以30日龄仔猪睾丸组织块为培养对象,应用飞利普TECNAI10电子显微镜对培养前后的生精细胞类别进行了观察,对培养后的组织块进行生精细胞分化程度鉴定,建立了仔猪睾丸组织生精细胞爬片体外培养模型。培养前后电镜观察及HE染色结果显示,培养前细胞种类主要有2种:支持细胞和精原细胞,有少数几个初级精母细胞;培养第20 d的睾丸组织块HE染色观察到3个精子细胞,电镜观察到2个精子细胞。证实,在没有添加睾酮的情况下,此培养体系能够提供睾丸组织块生精细胞分化所需要的条件,使非精子细胞类生精细胞减数分裂为精子细胞。     

山西票号错失变迁机遇的新制度经济学分析

19世纪末20世纪初,辉煌一时的山西票号在向现代银行过渡中曾出现过两次机遇,但都没能把握住。文章从新制度经济学的角度就票号错失变迁机遇进行了分析,指出其根源在于:第一次合组银行失败———初级行动团体的缺失。由于其内部制度导致了决策层创新能力的逐步弱化,阻滞了初级行动团体的形成;第二次合组银行失败———次级行动团体缺失。由于组织内部各利益主体无法达成一致意见导致合组计划付之东流。     

胚兔牙囊发育生物行为的组织形态学观察

研究胚兔的牙囊发育生物行为与人的牙囊发育是否相似 ,为人口腔疾病的研究提供模拟实验动物模型 ,采用光镜、电镜及激光扫描共聚焦显微镜对 4 3只胚兔的牙囊发育过程进行形态学观察。结果显示 ,牙囊来源于外胚间质 ,通过胚胎诱导形成牙支持组织 ,分化产生成牙骨质细胞、成骨细胞、成纤维细胞 ,形成牙骨质、固有牙槽骨、牙周韧带及其基质 ,对牙齿发育阶段具有保护和稳定作用 ,调控未来形成的牙周结构 ,在早期发育阶段首先出现 ,与人牙囊发育基本相似 ;最终牙囊在牙冠的顶部形成索引带 ,诱导继承牙萌出 ,在牙冠的根部形成牙支持组织 ,一部分牙囊细胞有程序性细胞死亡 ,以维持牙囊发育期内环境的生理平衡     

知识产权中的间接侵权探析

知识产权中的间接侵权有三种形式,即:帮助侵权、二次侵权和代位侵权。间接侵权不同于共同侵权,它与直接侵权也有联系但并不必然以之为前提,在我国立法中,规定间接侵权是很有必要的。     

云南省中小学毒品预防教育调查报告

中小学校毒品预防教育是一项十分重要的禁毒基础工作。目前云南省中小学校虽已开展了不同形式的毒品预防教育工作 ,但是 ,部分学校迫于升学压力 ,加之在校学生吸毒情况不突出等原因 ,并未将毒品预防教育列入学校的重要工作之一 ,不注重毒品预防教育效果。     

Secondary traumatic stress and vicarious traumatization in child welfare professionals in Serbia

Child welfare professionals in diverse positions are exposed to a variety of traumatic events including family violence and child abuse and neglect. This secondary exposure puts child welfare workers at the risk of experiencing Secondary Traumatic Stress (STS) and Vicarious Traumatization (VT). For the first time in Serbia, this study quantitatively investigates whether STS and VT are present in child welfare professionals employed in the social welfare centers, foster care and adoption agencies, residential care programs, and shelters for children and youth. It attempts to identify whether the type of service, time exposure to clients, and supervision function as risk or protective factors for negative outcomes. A convenience sample comprised of 135 child welfare professionals completed a series of self-reported measures. Findings indicate that VT and STS are present in this population. Differences in the presence of STS and VT were found according to the types of services offered and length of exposure. Contrary to expectations, supervision was not a protective factor with regards to STS and VT in this population.     

Combined Collection and Analysis of Inorganic and Organic Gunshot Residues

Gunshot residue (GSR) analysis and their interpretation provide crucial information on a criminal investigation involving the use of firearms. To date, several approaches have been proposed for the implementation of a combined sampling and analysis of inorganic (IGSR) and organic GSR (OGSR). However, it is not clear at this stage if concurrent analyses of both types of residue might be detrimental to the analysis of IGSR currently applied in forensic laboratories. Thus, this work aims to compare and evaluate three different protocols for the combined collection and analysis of IGSR and OGSR. These methods, respectively, involve the use of a modified stub (with two halves, one for the detection of IGSR and the other for the analysis of OGSR); the sequential recovery of GSR with two stubs mounted with different adhesives (double-sided carbon tape and Tesa® TACK) and the sequential analysis of IGSR and OGSR from a single carbon stub following carbon deposition. The detection of IGSR was carried out using SEM-EDX, while OGSR analysis was performed using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). Obtained results for experiments performed using Geco Sinoxid^® ammunition indicated that sequential analysis was the most suitable protocol for the combined collection and analysis of both IGSR and OGSR. A higher number of inorganic (characteristic and consistent) particles and higher concentrations of ethylcentralite, N-nitrosodiphenylamine, diphenylamine, and nitroglycerin were recovered with this method.     

Access and control of agro-biotechnology: Bt cotton,ecological change and risk in China

This article argues that if the introduction of genetically modified crops (GM crops) in developing countries is to be successful, we can and should not evade questions of access and control of technology. It implies probing into the experiences, perceptions and understanding of GM crops by the prime user: the farmer. Exactly in these respects the scholarly literature is remarkably silent. We know little about farmers' experiences and perceptions of GM crops' potential risks and benefits. This is evident when concentrating on a major GM crop – Bt cotton – and studying this in the context of China, its second largest producer in the world. Based on the results of a large survey, we demonstrate that Chinese farmers' awareness (‘having heard of’) and their understanding (‘being able to explain’) of Bt cotton is low. This may lead to ill-informed, distorted risk perceptions and a general inability to relate agricultural production problems to the specific nature of transgenic cotton cultivation. A great majority of the farmers find that the Chinese seed market was liberalised too early, in turn leading to a high incidence of ‘stealth transgenics’ or illegal seeds, the undermining of farmers' trust in private institutions, and a weakened biosafety regime. This finding points to the need for continued state intervention in the seed market, particularly in a developing context. Finally, we have discovered that farmers report a significantly lower reduction in pesticide use by Bt cotton than found in other studies. As suggested by recent research, we suspect that the higher pesticide use is necessary to control secondary pests – i.e. pests other than the cotton bollworm. We present empirical evidence that Chinese farmers perceive a substantive increase in secondary pests after Bt cotton was introduced.     

开发老年劳动力市场的必要性与路径研究

在平均预期寿命增加和低生育率的双重作用下,中国快速进入老龄化社会,给劳动力市场和经济持续发展带来了诸多挑战。中国老年劳动力市场具有巨大的潜力,充分利用51-64岁年龄人口将会有效增加我国劳动力供给,实现二次人口红利。在分析当前中国老年劳动力市场潜力及充分借鉴国外经验的基础上,提出了推行延迟退休政策、鼓励老年人灵活就业、加强老年劳动力培训和完善社会服务体系等开发老年劳动力市场的路径。