基因组的监察者

在显微镜下观察,活细胞显得很平静,但在平静的外表下,生化反应却在活跃地进行着.动植物细胞的DNA基因组包含了数以千计的基因,如果不加干涉,细胞的转录机制将同时转录基因组中全部基因:解开DNA双螺旋,将每个基因转录成单链的信使RNA,最后将信使RNA翻译成蛋白质.奇怪的是,很少量的双链RNA分子能够使蠕虫甚至其后代不自主地扭曲.     

Environmental influences upon firm entry into new sub-markets: Evidence from the worldwide hard disk drive industry conditionally

Firms need to access skills, capital and customers to enter into an industry initially and the choices they make to access these resources are likely to exert path dependent influences over subsequent entry behavior into new sub-markets. This paper explores how firms configure themselves to access skills, capital and customers and reports data on their association with whether and when firms enter new sub-markets in the worldwide hard disk drive (HDD) industry. While, as with other studies, there appear to be geographic differences between US and Japanese firms in sub-market entry behavior, these are shown not to simply reflect differences in region: US startup firms with former IBM personnel and Japanese incumbent firms with keiretsu linkages to their customers, exhibit different entry behavior than other firms in the same region. The analysis suggests that entry decisions are influenced by firms’ configuration choices to access needed resources and that the menu of configuration options available to firm managers varies across different institutional settings.     

A meta‐analysis of parent and teacher reports of depression among students with learning disabilities: Evidence for the importance of multi‐informant assessment

We conducted a meta‐analysis to examine depressive symptomatology among students with learning disabilities (LD), as reported by their parents and teachers. A 2006 meta‐analysis by Maag & Reid of the self‐reports of students with LD indicated that this group's higher report of depressive symptoms compared to non‐LD students was small in magnitude (d = .35). In our meta‐analysis, 31 studies in which depressive symptomatology among school‐age (K–12) students with LD was examined were included. The overall effect size was statistically significant and medium in magnitude (d = .75) and indicated that parents and teachers reported students with LD to experience significantly more depressive symptoms than non‐LD students experience. When integrated with Maag and Reid's findings, these results suggest that parents and teachers appear to report greater depressive symptomatology for students with LD than these students report for themselves. Due to the observed discrepancy, multi‐informant assessment practices and the need for clinical judgment are discussed. © 2011 Wiley Periodicals, Inc.     

Using analogy to improve abstract conditional reasoning in adolescents: not as easy as it looks

Abstract reasoning refers to the ability to reason logically with premises that do not allow reference to knowledge about the real world. This form of reasoning is complex and difficult, and at the same time, it is critical for understanding science and mathematics. Two studies examined the use of analogy as a method to bridge reasoning with familiar content and abstract reasoning among older adolescents. The results showed that the ability to make an appropriate analogy depends on reasoning ability. Neither of the two procedures used resulted in an improvement in abstract reasoning. However, generating an inappropriate analogy actually decreased abstract reasoning performance among students who showed greater initial levels of reasoning ability. These results highlight the problems associated with using familiar reasoning as a basis for learning abstract reasoning skills.     

Students' perceptions of Blackboard and Moodle in a Portuguese university

The use of learning management systems (LMS) has grown considerably in universities around the world. The University of Minho (UM) has pioneered in this area in Portugal, adopting Blackboard as its official LMS. Moodle is also used in UM in scattered initiatives, allowing for interesting comparisons. Previous studies comparing Blackboard and Moodle have been confined to limited samples and focused on students' perceptions only. In this paper, we also try to relate those perceptions to the impact of the LMSs on student level of engagement. We assess the extent and depth of use of the two LMSs, presenting the results of a study of students' perceptions and experience with both Blackboard and Moodle. Unlike previous studies, more students (46.5%) stated a preference for Blackboard over Moodle, while 34.7% preferred Moodle, and nearly 20% had no preference. Factors that might explain these results are explored in some detail. By and large, a basic utilisation is made of both platforms, as little more than electronic document repositories, in what Francis and Raftery, in 2005, designate as a Mode 1 level of engagement. We could, however, detect some instances of a more sophisticated Mode 2 utilisation, particularly with Moodle, underlining the role of faculty in integrating a sophisticated use of LMSs when designing their courses.     

Peer selection and socialization effects on adolescent intercourse without a condom and attitudes about the costs of sex

This study investigated peer selection and socialization effects on sexual behavior and attitudes using 1,350 15- to 18-year-old students participating in two waves of the National Longitudinal Study of Adolescent Health. Regarding socialization effects, friends' intercourse without condoms predicted later individual intercourse without condoms positively. Friends' attitudes about the costs of sex predicted later individual attitudes positively and intercourse without condoms negatively. The latter relation was stronger for females than for males. Regarding selection effects, individual attitudes predicted later friends' attitudes positively, but the strength of this effect varied by ethnicity. The results suggest that adolescents socialize friends to have similar sexual attitudes and behavior but tend to select friends based on similar attitudes rather than similar behaviors.     

Taking Care of Authenticity on the CBC’s Randy’s Vinyl Tap

This essay explores the radio program Randy’s Vinyl Tap, which is hosted by Randy Bachman and airs on CBC Radio 1 (2005-present). I argue that the show’s complex reception can be explained, in part, by the fact that it transgresses dominant conceptions of authenticity in both rock music and public broadcasting discourses. Drawing on the work of Mikhail Bakhtin, I explore ways in which Bachman evokes a “carnivalesque” approach to public communication.