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61.
A variety of researchers in the last fifteen years have described how people learn and use mathematics in out-of-school situations. These researchers have found that mathematics learning and practice in and out of school differ in a number of ways. In this paper we examine and discuss these differences while maintaining the position that while some differences may be inherent, many differences can be narrowed so that mathematics learning and practice in school and out of school can build on each other and be connected. Before discussing a framework that we think sheds some light on connecting these experiences, we present some research from several of our studies that illustrates some of the differences between in-school and out-of-school mathematics practice and lays the groundwork for the discussion of the framework.We then discuss Saxe's (1991) research framework for gaining insight into the interplay between sociocultural and cognitive development processes through the analysis of practice participation (p. 13). Although Saxe's framework is a method for studying the interplay between sociocultural and cognitive development processes, we propose that it may be helpful in working towards connecting in-school and out-of-school mathematics learning and practice. Thus, we discuss the framework with illustrations from our own research, and then elaborate on ways to make this interplay between in-school and out-of-school contexts more deliberate.  相似文献   
62.
Supported bimetallic nanoparticulate catalysts are an important class of heterogeneous catalysts for many reactions including selective oxidation, hydrogenation/hydrogenolysis, reforming, biomass conversion reactions, and many more. The activity, selectivity, and stability of these catalysts depend on their structural features including particle size, composition, and morphology. In this review, we present important structural features relevant to supported bimetallic catalysts focusing on Pd-based bimetallic systems and recently reported strategies to control them through different synthesis methodologies. Further, we focus on a few reactions that are relevant to environmental catalysis, i.e. CO oxidation, hydrocarbon oxidation, hydrodechlorination, and NO x decomposition, where Pd-based catalysts are often used successfully. In spite of much progress in these areas, still there is a need for more advanced catalytic technologies to address the grand challenges like environmental remediation. Some of the recent advances in the design of bimetallic catalysts were made because of the combined efforts of material scientists, spectroscopists, microscopists, catalysis chemists, and engineers through state-of-the-art characterization methodologies, mechanistic investigations, and structure-activity correlations. This review is aimed at inspiring scientists to rationally design catalysts for a green and sustainable future.  相似文献   
63.
More than 15 years after the introduction of a standards-based curriculum reform, the mathematics teachers are positive towards the reform message but have not changed their classroom practice accordingly. To improve the impact of future reforms, it is important to learn from this situation and to better understand the role of the national policy documents. The purpose of this study is therefore to examine how the standards-based reform in mathematics in Sweden was conveyed in the formal written curriculum. The research questions focus on to what extent and how clearly the national policy documents convey the message. The results show that the message is present to a large extent in the policy documents, but that it is vague and formulated with complex wording. The study gives concrete examples and shows in detail in what ways the documents are vague and complex.  相似文献   
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This study investigates the effects of state testing programs on the instructional practices of elementary teachers and the effects of such practices on their gifted students’ attitudes toward school and motivation. Results obtained from a national survey of elementary teachers, representing a variety of metropolitan areas and school poverty levels, as well as qualitative case studies from teachers in three states suggest that the perceptions teachers have of standards, tests, and students shape their classroom actions. These findings indicate that teachers are not likely to engage in effective classroom practices but instead engage in one‐size‐fits‐all practices. Implications of these perceptions on professional development and talent development are discussed.  相似文献   
66.
Motivational methods of teaching are topical subjects and much discussed issues regarding schools and education. The first question of our study covers student motivation and students' perception of their own schools' teaching methods. The second question reflects on how upper secondary school teachers perceive their roles as teachers, their thoughts on acquirement of knowledge and how learning takes place. The third question treats the subject of how school and education is organized. The upper secondary school the authors chose for the case study is a school that recruits students on a national basis and is directed towards the education of fire and rescue service personnel. The programme follows the national science curriculum and gives qualification for further studies at most universities. The school started in the autumn of 1998 and is known for being successful at working with student involvement, responsibility and subject integration. The study which was conducted during the autumn of 2007 included 32 students from two of the learning groups from the same year and started on the day of introduction of a new theme and finished with their presentation of results. The authors made observations, interviewed and through questionnaires studied how students comprehended the schools' working methods. We also interviewed their teachers and headmaster. The theoretic standpoint is Activity Theory (Chaiklin, S. & Lave, J. 1996; Knutagard, H., 2002; Vygotsky, L. S., 1986). The conclusions are that the students are encuitured into a school's activities that are similar to what students perceive as that of real life. It gives meaning and motivation to learning and makes it meaningful. They identify their own responsibility and cooperative learning as the most important parts. The teachers' own learning process and planning work is parallel to the work forms applicable to the students. They are all interdependent of each other since all the work areas are thematic. The school can be seen as an activity system where members interplay and communication develops a common culture.  相似文献   
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This paper investigates beginning teachers collaboratively making sense of and responding to the micropolitical environments of their schools. Drawing on a qualitative multi-case study conducted within the context of a university-sponsored, inquiry-based induction program, this research employs a community of practice frame to examine how novice teachers came to practice “micropolitical literacy.” The paper identifies four dimensions of micropolitical discourse that surfaced in the situated setting of the inquiry groups. The analysis further illustrates how beginning teachers, while participating in inquiry groups, coconstructed understandings of the organizational structures and professional cultures of their schools.  相似文献   
69.
Background: The Polish Medical Bibliography (Polska Bibliografia Lekarska) contains 350 000 records dating from 1979. These records from the fields of medicine, nursing, dentistry, health care systems and preclinical sciences are from nearly 300 biomedical journals published in Poland. Methods: We systematically searched the Polish Medical Bibliography Part II (1996–2006) CD‐ROM (July 2006) using both English and Polish phrases for randomized trials, manually checked results and, for the trials identified in this way, sought these on medline and embase . Results: Systematic searching identified records of 680 randomized trials from all areas of health care. Nearly 40% of these were not found on either medline or embase . Conclusions: The Polish Medical Bibliography should be of interest to health care information specialists concerned with comprehensive searches for trials.  相似文献   
70.

Introduction

Centrifugation is an essential step for plasma preparation to remove residual elements in plasma, especially platelets and platelet-derived microparticles (PMPs). Our working hypothesis was that centrifugation as a preanalytical step may influence some coagulation parameters.

Materials and methods

Healthy young men were recruited (N = 17). For centrifugation, two protocols were applied: (A) the first centrifugation at 2500 x g for 15 min and (B) at 2500 x g for 20 min at room temperature with a light brake. In protocol (A), the second centrifugation was carried out at 2500 x g for 15 min, whereas in protocol (B), the second centrifugation involved a 10 min spin at 13,000 x g. Thrombin-antithrombin (TAT) and plasmin-antiplasmin (PAP) complexes concentrations were determined by enzyme-linked immunosorbent assays. PMPs were stained with CD41 antibody and annexin V, and analyzed by flow cytometry method. Procoagulant activity was assayed by the Calibrated Automated Thrombogram method as a slope of thrombin formation (CAT velocity).

Results

Median TAT and PAP concentrations did not differ between the centrifugation protocols. The high speed centrifugation reduced the median (IQR) PMP count in plasma from 1291 (841-1975) to 573 (391-1010) PMP/µL (P = 0.001), and CAT velocity from 2.01 (1.31-2.88) to 0.97 (0.82-1.73) nM/min (P = 0.049). Spearman’s rank correlation analysis showed correlation between TAT and PMPs in the protocol A plasma which was (rho = 0.52, P < 0.050) and between PMPs and CAT for protocol A (rho = 0.74, P < 0.050) and protocol B (rho = 0.78, P < 0.050).

Conclusion

Centrifugation protocols do not influence the markers of plasminogen (PAP) and thrombin (TAT) generation but they do affect the PMP count and procoagulant activity.Key words: cell-derived microparticles, blood coagulation tests, centrifugation, preanalytical phase  相似文献   
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