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231.
There has been growing criticism over the aims, methods, and contents of practical work in school science, particularly concerning their tendency to oversimplify the scientific practice with focus on the hypothesis-testing function of experiments. In this article, we offer a reading of Johann Wolfgang von Goethe’s scientific writings—particularly his works on color as an exquisite articulation of his ideas about experimentation—through the lens of practical school science. While avoiding the hasty conclusions made from isolated experiments and observations, Goethe sought in his experiments the interconnection among diverse natural phenomena and rejected the dualistic epistemology about the relation of humans and nature. Based on a close examination of his color theory and its underlying epistemology, we suggest three potential contributions that Goethe’s conception of scientific experimentation can make to practical work in school science.  相似文献   
232.
Early calculation abilities in preschoolers are predictive of mathematics achievement in subsequent grades (e.g., Jordan et al. 2009). Two studies were conducted to evaluate concurrent and longitudinal predictors of early calculation skills. In the first study, 102 preschoolers (57.8 % female; mean age?=?60.57?±?8.66 months) were given vocabulary, language comprehension, and verbal working memory tasks and a test battery that evaluated components of early number competence (quantity comparison, counting, number line, size seriation, semantic knowledge of digits, visual-spatial memory). The children were also asked to complete early calculation tasks, including addition and subtraction calculations. The results of this task constituted the dependent variable. The results showed that vocabulary, size seriation, and visual-spatial memory were significant concurrent predictors of early calculation competence. In the second study, 43 children completed the early number competence battery at time 1 (53.5 % female; mean age?=?59.30?±?3.46 months) and the linguistic and early calculation tasks at time 2, about 10 months later (mean age?=?69.43?±?3.31 months). The analysis of the longitudinal predictors of early calculation showed significant effects for counting and size seriation. The implications for preschool assessment and intervention are discussed.  相似文献   
233.
1 Introduction Theboundaryintegralequationsariseinmanyproblemsofphysicsandengineering .Oneofthepri marymathematicalandnumericaldifficultiesofboundaryintegralequationappearstobethetreat mentofthesingularkernels.Therearethreediffer enttypesofsingularities…  相似文献   
234.
Drawing comparisons between students’ alternative solution strategies to a single mathematics problem is a powerful yet challenging instructional practice. We examined 80 preservice teachers’ when asked to design a short lesson when given a problem and two student solutions—one correct and one incorrect. These micro-teaching events were videotaped and coded, revealing that fewer than half of participants (43%) made any explicit comparison or contrasts between the two solution strategies. Those who did were still not likely to use additional support strategies to draw students’ attention to key elements of the comparison. Further, correlations suggest that participants’ mathematical content knowledge may be related to whether participants’ showed contrasting cases but not to whether they used specific pedagogical cues to support those comparisons. While these micro-teaching events differ from the interactive constraints of a classroom, they reveal that participants did not immediately orient toward differing student solutions as a discussion opportunity, and that future instruction on contrasting cases must highlight the utility of this practice.  相似文献   
235.
236.
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   
237.
This study investigates the difficulties students encounter in problem solving in the area of sciences. Contrary to usual approaches of a fundamental psychological basis, the research takes into account the sociological processes of learning and transmission in both the family and the school. The aim of the study is to see the extent to which the students have recognition and realisation rules in the micro‐context of problem solving (specific coding orientation) and to find out the reasons which may underlie their difficulties. Thus the data obtained are related to social class, race and gender and also to pedagogic practices (differing in power and control relations) and school science achievement in high level cognitive competencies. They are also related to children's cognitive level. The results show a strong relation between social class and specific coding orientation to problem solving. The relation is also strong for race and weaker for gender. Specific coding orientation is also strongly related to cognitive development and science achievement. These relations differ for the variables according to realisation and recognition rules and their various indices. The study shows the positive influence of pedagogic practice, which constitutes a crucial finding to pedagogic change.  相似文献   
238.
Opportunities for American Indian youth to meaningfully engage in school-based science, technology, engineering, and mathematics (STEM) experiences have historically been inadequate. As a consequence, American Indian students perform lower on standardized assessments of science education than their peers. In this article we describe the emergence of meaning for students—as well as their community—resulting from Indigenous culturally-based STEM curriculum that used an American Indian tradition as a focal context. Specifically, the game of snow snakes (Gooneginebig in Ojibwe) afforded an opportunity for STEM and culturally-based resources to work in unison. A case study research design was used with the bounded case represented by the community associated with the snow snake project. The research question guiding this study was: What forms of culturally relevant meaning do students and the community form as a result of the snow snake game? Results indicate evidence of increased student and community engagement through culturally-based STEM experiences in the form of active participation and the rejuvenation of a traditional game. Implications are discussed for using culturally-based contexts for STEM learning.  相似文献   
239.
The introduced study represents methodology and results of research focused on utilization of interactive whiteboard as didactic technology mediating information through multimedia worksheets applied in education process in pre-primary education. Its aim was to determine whether it can significantly increase the level of children’s acquired knowledge in the field of technical skills education and whether it can positively influence the development of children’s creative skills as a sign of their motivation. We observe that this issue in the way it is theoretically and practically established in this study can contribute by proposing education standards and set of multimedia worksheets in the technical field in Slovak pre-primary education.  相似文献   
240.
Objective: McKeown esophagectomy followed by cervical and abdominal procedures has been commonly used for invasive esophageal carcinoma. This minimally-invasive operative procedure in the lateral prone position has been considered to be the most appropriate method. We describe our experiences in minimally invasive McKeown esophagectomy (MIME) for esophageal cancer. Methods: Between March 2016 and February 2018, a total of 82 patients underwent MIME by a single group in our department (a single center). All procedure, operation, oncology, and complication data were reviewed. Results: All MIME procedures were completed successfully, with no conversions to open surgery. The median operative time was 260 min, and median blood loss was 100 ml. The average number of total harvested lymph nodes was 20.1 in the chest and 13.5 in the abdomen. There were no deaths within 30 postoperative days. Twenty cases (24.4%) developed postoperative complications, including anastomotic leak in 4 (4.9%), single lateral recurrent nerve palsy in 4 (4.9%), bilateral recurrent nerve palsy in 1 (1.2%), pulmonary problems in 3 (3.7%), chyle leak in 1 (1.2%), and other complications in 7 (including pleural effusions in 4, incomplete ileus in 2, and neck incision infection in 1; 8.54%). Average postoperative hospitalization time was 12 d. Blood loss, operation time, morbidity rate, and the number of harvested lymph nodes were analyzed by evaluating learning curves in different periods. Significant differences were found in operative time (P=0.006), postoperative hospitalization days (P=0.015), total harvested lymph nodes (P=0.003), harvested thoracic lymph nodes (P=0.006), and harvested abdominal lymph nodes (P=0.022) among different periods. Conclusions: Surgical outcomes following MIME for esophageal cancer are safe and acceptable. The MIME procedure for stages I and II could be performed proficiently and reached an experience plateau after approximately 25 cases.  相似文献   
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