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971.
Using data from the 1998 High School National Census from the Ministry of Education and Culture of Argentina, the present study examines relationships between school composition, some characteristics of schooling (such as institutional culture and climate), and students’ achievement in Mathematics in the last year of high school. The study applies multilevel linear modeling on the levels of student, school and state. It finds a close relationship between achievement in Mathematics and the variables of school composition and schooling processes. It shows that when both variables act together, the effect of all other variables significantly decreases. The variables of schooling processes, however, even when diminished in influence, nonetheless notably continue to affect students’ achievements. The study also identifes a reference model for future studies evaluating other institutional factors of learning.  相似文献   
972.
A written questionnaire was used to obtain information regarding Greek kindergarten teachers’ personal views on the concept of Environmental Education (EE). The questionnaire was also designed to obtain the teachers’ views relative to a series of theoretical and methodological issues concerning the application of EE. It was ascertained that the prevalent conception of the kindergarten teachers includes the following: (a) it is directed towards a knowledge-centered type of EE, (b) it is primarily centered on nature and its protection in terms of EE content, (c) it aims not only to shape citizens willing to adopt environmental measures recommended by the experts, but who will also actively participate in social actions for the protection of the environment, (d) it favors learning procedures in the environment with field study activities, (e) it must be compulsory in the kindergarten level.  相似文献   
973.
For an energy-efficient induction machine, the life-cycle cost (LCC) usually is the most important index to the consumer. With this target, the optimization design of a motor is a complex nonlinear problem with constraints. To solve the problem, the authors introduce a united random algorithm. At first, the problem is divided into two parts, the optimal rotor slots and the optimization of other dimensions. Before optimizing the rotor slots with genetic algorithm (GA), the second part is solved with TABU algorithm to simplify the problem. The numerical results showed that this method is better than the method using a traditional algorithm. Project (No. 601299) supported by the Science Foundation of Hebei Province, China.  相似文献   
974.
We present results from a classroom-based intervention designed to help a class of grade 10 students (14–15 years old) learn proof while studying trigonometry in a dynamic geometry software environment. We analysed some students’ solutions to conjecture-and-proof problems that let them gain experience in stating conjectures and developing proofs. Grounded on a conception of proof that includes both empirical and deductive mathematical argumentations, we show the trajectories of some students progressing from developing basic empirical proofs towards developing deductive proofs and understanding the role of conjectures and proofs in mathematics. Our analysis of students’ solutions is based on networking Boero et al.’s construct of cognitive unity of theorems, Pedemonte’s structural and referential analysis of conjectures and proofs, and Balacheff and Margolinas’ cK¢ model, while using Toulmin schemes to represent students’ productions. This combination has allowed us to identify several emerging types of cognitive unity/rupture, corresponding to different ways of solving conjecture-and-proof problems. We also show that some types of cognitive unity/rupture seem to induce students to produce deductive proofs, whereas other types seem to induce them to produce empirical proofs.  相似文献   
975.
Biochemical changes of natural actomyosin from fresh pale, soft, exudative (PSE) and normal pork were studied, and the effects of different storage temperatures and different incubation temperature and times on sample superprecipitation, total sulfhydryl (-SH) content, and ATP (adenosine triphosphate) sensitivity were investigated. The results demonstrated that ATPase activity and thermal stability of PSE actomyosin were lower than those of normal pork; and that PSE actomyosin had higher -SH content than that of normal pork at all incubation temperatures and times tested.  相似文献   
976.
Defiant behavior in two- and three-year-olds is a natural expression of a young child’s growing autonomy, and, although frustrating to adults, is a natural phase of a child’s socio-emotional growth. L.S. Vygotsky’s socio-historical theory of the development included a discussion of “crisis” periods, one of which he felt occurred at age three. The crisis that Vygotsky asserted occurred at three is characterized by a group of seven “behaviors”, all of which indicate a struggle with the child’s position in relation to family social structures. This study examined the occurrences and characteristics of defiant behavior in two-and three-year-old children during outdoor play at a child development center, and the existence and context of defiant behaviors the modern childcare setting. Patterns in defiant behaviors during play in different age groups were apparent, and suggested an instrument to facilitate the documentation and analysis of defiant behavior in modern group-care settings.  相似文献   
977.
There have been relatively few single case studies concerned with the remediation of spelling deficits among developmental impairments. Among these there have been a small number that targeted specific components of the spelling process and used linguistic theories as theoretical underpinning for the development of remediation procedures. This single case study examines remediation of writing skills and aims at evaluating two different lexically based intervention methods, one of which used Optimality Theory as its basis. We applied a rule-based remediation and an intervention method using whole-word forms to a child with selective impairments in the lexical-graphemic components. The investigation was done with words in which phoneme-grapheme-correspondences in word final position change due to voicing neutralization. The individual exhibited a method- and item-specific effect with respect to the rule-based method. In addition, a transfer effect to untreated items and a generalization effect to untrained but related tasks was observed. The absence of a method-specific and a generalization effect for the whole-word form intervention and the success of the rule-based method is determined by the specific cognitive component(s)s that constitute the source of the deficit and the appropriateness of Optimality Theory to address this particular deficit.  相似文献   
978.
The results of this study conducted at the University of Michigan (n = 289) indicate that students with more experiences with diversity, particularly enrollment in diversity courses and positive interactions with diverse peers, are more likely to score higher on academic self-confidence, social agency, and critical thinking disposition. In addition, the study provides evidence that diversity experiences may work together to foster development of certain aspects of self.The work reported herein is supported under the National Institute for Student Achievement, Curriculum and Assessment program, agreement number R305T990402-00, CFDA/Subprogram No: 84.305T, as administered by the Office of Educational Research and Improvement (OERI), U.S. Department of Education. The findings and opinions expressed in this report do not reflect the position or policies of OERI or the U.S. Department of Education.  相似文献   
979.
In two experiments with rats, we examined the developmental emergence of conditioned freezing following trace and short-delay conditioning and also included a long-delay comparison group. In the short-delay and trace groups, a 10-sec conditioned stimulus (CS) was paired with shock; for the trace rats, a 10-sec trace interval followed CS termination. The long-delay groups received a 20-sec CS paired with shock, to equate for the longer interstimulus interval (ISI) in the trace group. Trace conditioning emerged later in development than did short-delay conditioning (see Moye & Rudy, 1987). Importantly, long-delay conditioning emerged in parallel with trace conditioning, at a similar time, and with similar strength. These findings suggest a role for the longer ISI, as opposed to the unfilled gap per se, in the late emergence of trace conditioning. The role of the hippocampus in trace conditioning and the possibility that young rats encode the temporal relationship between CSs and unconditioned stimuli are also considered.  相似文献   
980.
Objective: To investigate the cytokine response pattern (IL-4/IFN-γ) in infants with RSV infections and bronchiolitis during the acute phase. Methods: Four-color flow cytometry was used to measure intracellular IL-4 and IFN-γ expressions in peripheral blood CD3+ and CD8+ lymphocytes from RSV-infected and bronchiolitis infants. Serum IL-4 and IFN-γ levels were also determined. Results: RSV-infected and bronchiolitis infants showed no statistical differences from not-RSV-infected or pneumonia infants and control in the frequency of IL-4 and IFN-γ expressions in CD3+CD8- lymphocytes, showed no obvious Th1/Th2 imbalance, while IFN-γ was expressed much more frequently in CD3+CD8+ lymphocytes. Systematically, RSV-infected and bronchiolitis infants showed much lower levels of serum IL-4 and IL-4/IFN-γ ratios and much higher serum IFN-γ levels than control. However, there were no statistical differences in the above three indices between RSV-infected and not-RSV infected infants or between bronchiolitis and pneumonia infants, except that bronchiolitis infants had a higher level of serum IFN-γ than pneumonia infants statistically. Conclusions: There is no type-2 cytokine response predominance in the acute phase of RSV infection and bronchiolitis. IL-4 production is suppressed and IFN-γ production upregulated, the latter being most prominent in bronchiolitis infants.  相似文献   
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