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71.
The act of revising is an important aspect of academic writing. Although revision is crucial for eliminating writing errors and producing high-quality texts, research on writing expertise shows that novices rarely engage in revision activities. Providing information on writing errors by means of peer feedback has become a popular method in writing instruction. However, despite its popularity, students have difficulties in leveraging the potential of peer feedback: feedback uptake is low and students engage in little revision. Instructional support might help learners to make sense of peer feedback and to reflect on the provided information more deeply. The present study investigated the effect of sense-making support on feedback uptake as well as on revision skills, in particular problem detection and problem correction. In an experimental study, 73 university students were randomly assigned to conditions with or without sense-making support. The results indicate that feedback uptake improved concerning two out of three variables: students in the condition with sense-making support made fewer new errors and rejected more incorrect feedback comments. Students’ revision skills only improved with regard to problem detection. Overall, we were able to show that peer feedback alone might not be sufficient to make successful changes in the text and improve revision skills. Sense-making support proved to be effective to some extent and partially helped to maximize the benefits of peer feedback.  相似文献   
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Given that grammatical and spelling errors have been found to influence perceived competence and credibility in written communication, this study examined how a student’s grammar and spelling errors affect how other students respond to the student’s postings in four online debates hosted in asynchronous threaded discussions. Message-response exchanges were sequentially analyzed to identify patterns in students’ replies to arguments and challenges with counter-challenges, explanations, and evidentiary support posted by students that exhibited low versus high number of grammatical and spelling errors. Although no causal inferences can be drawn from this study, the findings nevertheless suggests that: (a) arguments posted by high-error students are more likely to be challenged than arguments posted by low-error students; (b) exchanges between high-error students can amplify the effects of grammar/spelling errors; and (c) higher levels of argumentation can be achieved by placing students into groups that are heterogeneous in writing skills in general. The findings and methods used in this study lay the groundwork for further research on strategies for managing individual differences in students’ grammar and spelling (and other student behaviors in general) and increasing the level of critical discourse in online discussions.  相似文献   
74.
A novel “Whiteheadean” science program was initiated in England and Wales in September 2006. Following a critical House of Commons report in 2002, the government altered the National Curriculum targets and thus forced the Examination Boards to alter their specifications in order to come in line. Assessment at GCSE level (i.e., the 14-16 year cohort) was criticised for: a) failing to inspire students to continue with science, b) discouraging students from thinking for themselves, c) neglecting contemporary science, d) lacking flexibility, and e) making practical work into a tedious and dull activity. The British government has insisted that all pupils in state funded schools must know the names of some modern scientists and their work. They must discuss some current scientific problems. History and philosophy of science is included under the topic heading “How Science Works.” In Chemistry these objectives have destroyed the traditional linear top-down sequential approach of teaching into an approach based more closely on Whiteheadean lines (cf., the ideas expressed in The Aims of Education, 1926, Chapters 1-3).  相似文献   
75.
The aim was to study the genotoxic effect of high concentration of thyroxine (T4) in vivo in peripheral blood lymphocytes (PBL) of the patients suffering from thyroid disorders. The effect was compared by performing in vitro experiments with addition of increasing concentration of T4 (0.125–1 µM) in whole blood samples from healthy donors. Cytokinesis-blocked micronuclei (CBMN) assay method was used to assess the DNA damage in the PBL. The study included 104 patients which were grouped as control (n = 49), hyperthyroid (n = 31) and hypothyroid (n = 24). A significant increase in micronuclei (MN) frequency was observed in hyperthyroid patients when compared with the hypothyroid and euthyroid group thereby suggesting increased genotoxicity in hyperthyroidism (p < 0.001). A significant increase in MN frequency was observed at T4 concentration of 0.5 µM and above when compared to lower T4 concentrations (0.125 and 0.25 µM) and basal in in vitro experiments (p = 0.000). The results indicate that the T4 in normal concentration does not exhibit the genotoxic effect, as observed in both the in vivo and in vitro experiments. The toxicity of T4 increases at and above 0.5 μM concentration in vitro. Therefore acute T4 overdose should be handled promptly and effectively so as to avoid the possible genotoxic effect of high concentration of T4 in vivo.  相似文献   
76.
Infrared (IR) absorption spectra and X-ray powder diffraction (XRD) patterrns of sexpenfine cat's eye from Sichuan Province have been investigated, and infrared absorption bands of the serpentine have been assigned in this paper. The results indicate that the bands near 3 600 - 3 700 cm^-1 belong to the stretching absorption band VOH, the bands in 948 - 1 100 cm^-1 axe assigned to the stretching vibraling band Usvo, and the bands at 600 570 and 440 cm^-1 respectively belong to the bending vibration band VOH, δMg-O and δSi-O. The serpentine cat' s eye includes two types: chrysotile and antigorite. Chrysotile has a sharp and intensive band at 3 688 cm^-1 and a weak band at 3 643 cm^-1 , while antigorite has only one intensive band in the region. At vibration band VSi-O, chrysotile and antigorite have a similar feature at 1 071 cm^-1, but the band at 980 cm^-1 in anfigorite has been split into two bands in chrysotile - a strong one at 1 027 cm^-1 and a weak one at 949 cm^-1. In addition, antigorite has a characteristic bending vibrating band δMg-O at 570 cm^-1. Based on the analysis of the feature of crystal structure, their IR differences axe well explained.  相似文献   
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The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments.  相似文献   
80.
Abstract This study focuses on the effect of doctoral and postdoctoral studies at leading research universities in the USA on constructing the academic identity of Israeli students. The findings are based on constant comparative analysis of semi-structured interviews with 27 Fulbright alumni. The results show that while American scientific standards become a model for the Israeli scientists, Israeli culture and identity become much more evident, for better or worse. Several ways of handling these identities were recognized and include: the intertwine method, ordering, and buffering. Further theoretical and practical implications are discussed.  相似文献   
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