被子植物精细胞分离和特性研究进展     

朱维红  张妍  崔彬彬 《保定学院学报》2020,(3):114-121

精细胞分离是研究雄性生殖发育的前提之一,近半个世纪以来,人们运用不断更新的生物实验技术,对被子植物精细胞开展了分离及细胞分子特征的研究。分析被子植物精细胞分离方法,总结精细胞二型性与倾向性、细胞融合方面的研究成果,并对其研究意义和前景进行讨论。  相似文献   

编辑审稿的思维方法探讨   总被引：1，自引：0，他引：1  

李荣青  沈志宏 《编辑学报》1992,4(1):14-16

本文运用系统论、信息论、控制论的原理,探讨科技编辑在审稿中的思维方法问题,提出了前瞻性的逻辑设问式审稿法,认为应将论文置于该研究领域的系统框图中,根据论文及多方面提供的有关信息进行逻辑设问,通过综合的总体评价,对拟刊用的论文实行目标质量控制。  相似文献   

Reconceptualising educational assessment in South Africa — testing times for teachers     

John Pryor  Cassius Lubisi 《International Journal of Educational Development》2002,22(6)

This paper explores some of the problems arising when Continuous Assessment (CA) is grafted onto established pedagogic practices. It focuses on three issues: teachers' restricted understandings of assessment, teachers' emphasis on criteria that demonstrate concern with social control, and some of the problems connected with peer assessment. Two vignettes derived from fieldwork associated with a project to improve the quality of primary education are used to raise the issues. We argue that the development of desired practices is hampered above all by tacit values in tension with those underpinning the new curriculum. These values, together with the complexity of curriculum design, create serious problems of manageability and interpretation, which can only be addressed through detailed interactive in-service training, aimed at reconceptualising teachers' notions of assessment.  相似文献   

Correlates of verbally aggressive communication in adolescents     

Charles Atkin  Sandi Smith  Anthony Roberto  Thomas Fediuk  Thomas Wagner 《Journal of Applied Communication Research》2002,30(3):251-268

This investigation identifies demographic, media, and social correlates of verbally aggressive communication in adolescence. Mail surveys were completed and returned by 2,300 adolescents between the ages of 13 and 15. These adolescents were asked about the prevalence of verbal and physical aggression, the context in which it occurred, demographics, and the interpersonal and media influences in their lives. The results indicate that verbal aggression is widespread, that committing and experiencing verbal aggression is largely reciprocal, that there is a strong relationship between committing verbal and physical aggression, and that peer social influence and listening to violently oriented music are mildly related to verbal aggression in adolescents. These findings suggest more resources should be allocated to teaching adolescents to understand and control verbal aggression. Further, they provide important answers to many prevention and intervention programmatic questions, including context, content, and targeting concerns. Since the negative consequences of verbal aggression are severe and long lasting, decreasing this destructive communication behavior should significantly improve the lives of many adolescents. These and other practical implications are expanded upon and discussed.  相似文献   

国外高校图书馆同伴教育服务现状及启示     

明均仁  张石琦  冯兵 《图书馆工作与研究》2022,(1)

本文选取美国、英国、加拿大共14所高校图书馆作为调研对象,对其同伴教育的服务命名、服务模式、栏目设置、服务对象、开展形式5个方面展开系统调研,重点从宣传途径、服务内容及运行管理层面把握同伴教育服务成功的关键要素,并从拓宽宣传渠道、多方联合推广、创新服务形式、提升用户体验、加强评估反馈、注重管理监督等方面优化图书馆服务,以启示我国图书馆同伴教育服务的构建和发展。  相似文献   

国际上同行评议典型做法及对我国的启示   总被引：1，自引：0，他引：1  

肖妍 《数字图书馆论坛》2022,(1)

同行评议一直是最权威、最有效的科学评价方式,美国、日本、欧盟等发达国家和国际组织都建立较为完整的同行评议制度,制定同行评议政策法规,建立标准化的评议流程,针对不同类型的项目采取不同评议方法。面对科技创新高质量发展的新要求、新任务,本文从加强相关法规体系建设、建立规范化的同行评议准则、构建完善的同行评议专家库、探索因项制宜的同行评议方式、大力营造良好的同行评议生态环境等方面对规范和完善我国同行评议制度提出对策建议。  相似文献   

Peer victimization,deviant peer affiliation and impulsivity: Predicting adolescent problem behaviors     

《Child abuse & neglect》2016

Abundant evidence has demonstrated an association between peer victimization and adolescent problem behaviors. However, there is a large gap in knowledge about the potential mediators that associate peer victimization with problem behaviors and the potential moderators that exacerbate or buffer this association. The current study examined whether deviant peer affiliation mediated the association between peer victimization and problem behaviors and whether the direct and indirect associations were moderated by impulsivity. A sample of 1401 adolescents (50.1% boys, 11–14 years old) completed anonymous questionnaires regarding peer victimization, impulsivity, deviant peer affiliation, and problem behaviors. Gender, age and socioeconomic status (SES) were controlled for in the analyses. Structural equation models showed that peer victimization was significantly associated with more problem behaviors, and this association was mediated by deviant peer affiliation. Impulsivity moderated both the direct association (peer victimization → problem behaviors) and the second stage of the indirect path (deviant peer affiliation → problem behaviors). Specifically, these associations were especially stronger for adolescents with higher impulsivity. Identifying the processes by which peer victimization is associated with adolescent problem behaviors has important implications for an integrative framework of theory and prevention.  相似文献   

实轴增量式光电编码器测量电路的设计   总被引：1，自引：0，他引：1  

李劲松 《实验室研究与探索》2007,26(2):12-15

介绍了如何设计增量式光电编码器的输出信号处理电路,并从该电路设计的四个方面着手,较为详细地阐述了电路组成的构思、设计及实现过程。  相似文献   

香菇菌株9907的选育及生物学特性     

刘卫今  刘胜贵 《怀化学院学报》2005,24(2):71-73

从怀化市及沅陵、中方、麻阳等县采集野生香菇子实体,通过分离、初筛、复筛和栽培试验,选育出一株较好的菌株香菇9907.香菇菌株9907属于低温结实型,菌丝体生长速度快,花菇率及生物学效率均较高,适合代料栽培.  相似文献   

Hybrid ants-like search algorithms for P2P media streaming distribution in ad hoc networks     

ZUO Dong-hong DU Xu YANG Zong-kai 《浙江大学学报(A卷英文版)》2007,8(8):1191-1198

Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions,po-tential high loss rate and the decentralized architecture. To support long and high-quality streams,one viable approach is that a media stream is partitioned into segments,and then the segments are replicated in a network and served in a peer-to-peer(P2P) fashion. However,the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm(HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks,such as low transmitting latency,less jitter times,and low unnecessary traffic. We quantify the performance of our scheme in terms of response time,jitter times,and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks.  相似文献