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91.
Susan Herring Kirk Job-Sluder Rebecca Scheckler Sasha Barab 《The Information Society》2002,18(5):371-384
A common phenomenon in online discussion groups is the individual who baits and provokes other group members, often with the result of drawing them into fruitless argument and diverting attention from the stated purposes of the group. This study documents a case in which the members of an online community--a feminist web-based discussion forum--are targeted by a "troll" attempting to disrupt their discussion space. We analyze the strategies that make the troller successful and the targeted group largely ineffectual in responding to his attack, as a means to understand how such behavior might be minimized and managed in general. The analysis further suggests that feminist and other nonmainstream online forums are especially vulnerable, in that they must balance inclusive ideals against the need for protection and safety, a tension that can be exploited by disruptive elements to generate intragroup conflict. 相似文献
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During backstroke, an optimum shoulder entry angle of 180° has been anecdotally suggested; however, this has yet to be investigated biomechanically. The aim of this study was to quantify shoulder entry angles for advanced and intermediate backstroke swimmers. Six advanced (season's best?<150?s) and six intermediate (season's best?>160?s) 200-m backstroke swimmers had markers applied to the medial humeral epicondyles and glenoid cavities. Following a familarization period, participants completed backstroke swimming trials (90?s each) in a swimming flume at 50%, 60%, 70%, and 80% of their season's best 200-m velocity. A camera positioned above the flume recorded frontal plane motion, which was digitized and analysed in Simi Motion Systems. The mean peak angle between the upper arm and the line of progression was established in ten strokes for each participant. The results showed backstroke shoulder entry angles for advanced swimmers (170°) were significantly closer to the suggested optimum 180° compared with those of intermediate swimmers (161°). The non-dominant arm displayed values closer to the optimum (171°), while swimming speed had no effect on backstroke shoulder entry angle. In conclusion, backstroke shoulder entry angle may help discriminate between advanced and intermediate backstroke swimmers and may be influenced by laterality dominance, being independent of swimming speed. 相似文献
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Midsession reversals with pigeons: visual versus spatial discriminations and the intertrial interval
Jennifer R. Laude Jessica P. Stagner Rebecca Rayburn-Reeves Thomas R. Zentall 《Learning & behavior》2014,42(1):40-46
Discrimination reversal learning has been used as a measure of species flexibility in dealing with changes in reinforcement contingency. In the simultaneous-discrimination, midsession-reversal task, one stimulus (S1) is correct for the first half of the session, and the other stimulus (S2) is correct for the second half. After training, pigeons show a curious pattern of choices: They begin to respond to S2 well before the reversal point (i.e., they make anticipatory errors), and they continue to respond to S1 well after the reversal (i.e., they make perseverative errors). That is, pigeons appear to be using the passage of time or the number of trials into the session as a cue to reverse, and are less sensitive to the feedback at the point of reversal. To determine whether the nature of the discrimination or a failure of memory for the stimulus chosen on the preceding trial contributed to the pigeons’ less-than-optimal performance, we manipulated the nature of the discrimination (spatial or visual) and the duration of the intertrial interval (5.0 or 1.5 s), in order to determine the conditions under which pigeons would show efficient reversal learning. The major finding was that only when the discrimination was spatial and the intertrial interval was short did the pigeons perform optimally. 相似文献
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Despite the impact of genetics on daily life, biology undergraduates understand some key genetics concepts poorly. One concept requiring attention is dominance, which many students understand as a fixed property of an allele or trait and regularly conflate with frequency in a population or selective advantage. We present the Dominance Concept Inventory (DCI), an instrument to gather data on selected alternative conceptions about dominance. During development of the 16-item test, we used expert surveys (n = 12), student interviews (n = 42), and field tests (n = 1763) from introductory and advanced biology undergraduates at public and private, majority- and minority-serving, 2- and 4-yr institutions in the United States. In the final field test across all subject populations (n = 709), item difficulty ranged from 0.08 to 0.84 (0.51 ± 0.049 SEM), while item discrimination ranged from 0.11 to 0.82 (0.50 ± 0.048 SEM). Internal reliability (Cronbach''s alpha) was 0.77, while test–retest reliability values were 0.74 (product moment correlation) and 0.77 (intraclass correlation). The prevalence of alternative conceptions in the field tests shows that introductory and advanced students retain confusion about dominance after instruction. All measures support the DCI as a useful instrument for measuring undergraduate biology student understanding and alternative conceptions about dominance. 相似文献
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Michelle Gordon Allison Haack Rebecca Vernon Tiffany Saulter Debora Shaw 《Public Library Quarterly》2014,33(2):145-154
How do public libraries develop their collections of high-demand materials for the “I want it now” generation? Ten public libraries’ holdings of fiction and nonfiction bestseller titles were observed over a four-week period. The number of copies rose fairly consistently, with the five fiction titles having roughly about twice the number of copies as the five nonfiction titles. The ratio of holds to copies averaged 2.7:1 and ranged from 0.8:1 to 6.5:1. Demand for e-books was consistently higher than the number of copies available, averaging more than 4:1 across all libraries. 相似文献
99.
Annie Nickum Emily Johnson-Barlow Rebecca Raszewski Ryan Rafferty 《Journal of the Medical Library Association》2022,110(3):358
Objective:Point-of-care tools (PoCTs) provide evidence-based information on patient care and procedures at the time of need. Registered nurses have unique practice needs, and many PoCTs are marketed to support their practice. However, there is little reported evidence in the literature about evaluating nursing-focused PoCTsCase Presentation:The investigators developed a rubric containing evaluation criteria based on content, coverage of nursing topics, transparency of the evidence, user perception, and customization of PoCTs for supporting nursing practice. The investigators selected five PoCTs cited in the literature and of interest to local nursing leadership: ClinicalKey for Nursing, DynaMed, Lippincott''s Advisor and Procedures, Nursing Reference Center Plus, and UpToDate. Application of the rubric found Lippincott had the highest coverage of diagnoses, while ClinicalKey for Nursing had strong content focused on interventions and outcomes. Nursing Reference Center Plus provided the most well-rounded coverage of nursing terminology and topics. DynaMed and UpToDate were more transparent with indicating conflict of interest, but both had lower coverage of nursing terminology, content, and care processes.Conclusion:None of the five PoCTs strongly met all of the evaluated criteria. The rubric developed for this study highlights each PoCT''s strengths and weaknesses that can then be used to inform the decision-making process based on priorities and budget. The investigators recommend licensing a nursing PoCT and a PoCT like DynaMed or UpToDate to provide comprehensive, evidence-based, patient care coverage and to meet the diverse information needs of nurses. 相似文献
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