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1.
Learners’ ability in dealing with socio-scientific issues has been highlighted in contemporary science education. This study explored the effects of different on-line searching activities on high school students’ cognitive structure outcomes and informal reasoning outcomes. By using a quasi-experimental research approach, thirty-three students were assigned to a “guided searching task group”, while thirty-five students were assigned to an “unguided searching task group”. The treatments of this study were two different on-line searching activities. All the participants were asked to search relevant information regarding nuclear power usage on the Internet during the period of two classes (100 min). However, the students in the un-guided searching task group were asked to search freely, while those in the guided searching task group were provided with a searching guideline. The participants’ cognitive structures outcomes as well as their informal reasoning outcomes regarding nuclear power usage were assessed before and after the conduct of on-line searching tasks. The results of ANCOVA revealed that the students in the guided on-line searching task group significantly outperformed their counterparts in the extent (p < 0.01) and the richness of their cognitive structures (p < 0.01). Also, they significantly outperformed their counterparts in the usage of the two information processing strategies, “comparing” (p < 0.05) and “inferring or explaining” (p < 0.05). Moreover, it was also found that the students in the guided on-line searching task group only outperformed their counterparts in their supportive argument construction (p < 0.05). In other words, the guided searching tasks did help the students obtain better cognitive structure outcomes; however, the increments on their cognitive structure outcomes may only help them to propose more supportive arguments, but their rebuttal construction (an important indicator for their reasoning quality) was not particularly improved.  相似文献   

2.
This paper presents a curriculum, textbook and test result analysis for the new (to California) elementary school “Key Standard” mathematics curriculum, transplanted in 1998 from it's foreign roots in Asia and Europe, locations with far different cultural and economic backgrounds. Based on topic analysis methods developed by Michigan State University, this curriculum is a “quality” curriculum, since it is closely aligned with the curriculum of the six leading TIMSS math countries. Five-year test results are presented for two cohorts totaling over 13,000 students, all from four “early adoption” urban districts where 68% of the students were economically disadvantaged. Included are two cohorts of English learning immigrants totaling over 4,400 students. Performance was found to be statistically superior to similar (control) districts which continued with the old 1991 curriculum and textbooks (0.003 < p < 0.015). The focus of this paper is on the transition from far-below to above average learning performance of these students over the 1998–2002 period.  相似文献   

3.
INTRODUCTION Telomeres are distinctive DNA-protein struc-tures that cap the ends of linear chromosomes.It is very important to keep the chromosomes stabilization.Telomerase activity is closely linked to attainment of cellular immortality,a step in carcinogenesis,while lack of such activity contributes to cellular senes-cence.Telomerase is activated in more than85%ofmalignant tumors(Hiayma et al.,1997).Human te-lomeric repeat binding factor1(TRF1)is a telomere associated with proteins a…  相似文献   

4.
Internet-mediated joint suicides or “Net group suicides” (Net shinjū) has become a significant social problem in Japan since 2002. Despite a privileged view of suicide-related cyberspaces as a murky underworld, there has been little study about how the participants of such spaces interact and perform their “suicidal” identity. Viewing cyberspace as a unique discursive playground that sprouts a myriad of transgressive narratives, this paper examines “Suicide Club” (Jisatsu Club) an online discussion forum that facilitated the largest “Net group suicide” in Japanese history. A thematic content analysis of actual postings on “Suicide Club” reveals the double-edged nature of the forum. While some participants were determined to seek suicide companions or what I metaphorically call “suicide machines,” others used the board as a social outlet to freely disclose their pent-up struggles, attempting to collectively transgress social taboos of suicide.
Yukari SekoEmail:
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5.
In this paper,we investigate the effect and the possible mechanism of high glucose levels on the calcification of human aortic smooth muscle cells (HASMCs).HASMCs were divided into four groups: normal glucose group (NG),osmolality control group (OC),high glucose group (HG,HASMCs culture medium containing 30 mmol/L glucose),and high glucose plus recombinant human Noggin protein (bone morphogenetic protein-2 (BMP-2) antagonist) group (HN).The mRNA levels and the protein expressions of BMP-2 and core binding factor alpha-1 (Cbfα-1) were measured by real-time quantitative polymerase chain reaction (PCR) and Western blot.After induced by 10 mmol/L β-glycerol phosphoric acid,cells were harvested for assessments of alkaline phosphatase (ALP) activities at Days 1,2,and 3,and intracellular calcium contents at Days 7 and 14,respectively.High glucose levels increased the mRNA levels and the protein expressions of BMP-2 and Cbfα-1 (P0.05).The expression of Cbfα-1 was partially blocked by Noggin protein (P0.05),while BMP-2 was not (P0.05).After being induced by β-glycerol phosphoric acid,high glucose levels increased the ALP activity [(48.63±1.03) vs.(41.42±2.28) U/mg protein,Day 3;P0.05] and the intracellular calcium content [(2.76±0.09) vs.(1.75±0.07) μmol/mg protein,Day 14;P0.05] in a time-dependent manner when compared with the NG group,while the ALP activity could not be blocked by Noggin protein [(48.63±1.03) vs.(47.37±0.97) U/mg protein,Day 3;P0.05].These results show that high glucose levels can evoke the calcification of HASMCs by inducing osteoblastic trans-differentiation and intracellular calcium deposition via the BMP-2/Cbfα-1 pathway,which can be partially blocked by Noggin protein.  相似文献   

6.
Background: Sevoflurane and propofol are effective cardioprotective anaesthetic agents, though the cardioprotection of propofol has not been shown in humans. Their roles and underlying mechanisms in anesthetic postconditioning are unclear.Mitochondrial permeability transition pore (MPTP) opening is a major cause of ischemia-reperfusion injury. Here we investigated sevoflurane- and propofol-induced postconditioning and their relationship with MPTP. Methods: Isolated perfused rat hearts were exposed to 40 min of ischemia followed by 1 h of reperfusion. During the first 15 min of reperfusion, hearts were treated with either control buffer (CTRL group) or buffer containing 20 μmol/L atractyloside (ATR group), 3% (v/v) sevoflurane (SPC group),50 μmol/L propofol (PPC group), or the combination of atractyloside with respective anesthetics (SPC ATR and PPC ATR groups). Infarct size was determined by dividing the total necrotic area of the left ventricle by the total left ventricular slice area (percent necrotic area). Results: Hearts treated with sevoflurane or propofol showed significantly better recovery of coronary flow,end-diastolic pressures, left ventricular developed pressure and derivatives compared with controls. Sevoflurane resulted in more protective alteration of hemodynamics at most time point of reperfusion than propofol. These improvements were paralleled with the reduction of lactate dehydrogenase release and the decrease of infarct size (SPC vs CTRL: (17.48±2.70)% vs (48.47±6.03)%,P<0.05; PPC vs CTRL: (35.60±2.10)% vs (48.47±6.03)%, P<0.05). SPC group had less infarct size than PPC group (SPC vs PPC:(17.48±2.70)% vs (35.60±2.10)%, P<0.05). Atractyloside coadministration attenuated or completely blocked the cardioprotective effect of postconditioning of sevoflurane and propofol. Conclusion: Postconditioning of sevoflurane and propofol has cardioprotective effect against ischemia-reperfusion injury of heart, which is associated with inhibition of MPTP opening. Compared to propofol, sevoflurane provides superior protection of functional recovery and infarct size.  相似文献   

7.
Beth Hatt 《The Urban Review》2007,39(2):145-166
How smartness is defined within schools contributes to low academic achievement by poor and racial/ethnic minority students. Using Holland et al.’s (1998) [Holland, D., Lachicotte, W., Skinner, D., & Cain, C. (Eds.) (1998). Identity and agency in cultural worlds. Cambridge, MA: Harvard University Press.] concept of “figured worlds,” this paper explores the “figuring” of smartness through the perspectives of marginalized youth. The youth made key distinctions between being book smart vs. street smart. This distinction is a direct challenge by the youth to the dominant discourse of smartness or “book smarts” as it operates in schools. To the youth, “street smarts” are more important because they are connected to being able to maneuver through structures in their lives such as poverty, the police, street culture, and abusive “others.” This distinction is key because street smarts stress agency in countering social structures whereas, for many of the youth, book smarts represented those structures, such as receiving a high school diploma. Implications for schools and pedagogy are discussed. B.A. earned from Indiana University – Bloomington, Masters and Ph.D. earned from University of North Carolina at Chapel Hill. Beth Hatt Fis an Assistant Professor of Educational Administration and Foundations at Illinois State University where she teaches research methods and social foundations of education. Her current research explores smartness as a cultural construct in schools and the media.  相似文献   

8.
Based on empirical findings and theoretical considerations related to the field of expertise research, the importance of “types” and “qualities” of knowledge in relation to problem solving in physics was investigated. The students (N =138) in this study had a level of competence that corresponds to an intensive beginner college course in physics. It was found that conceptual declarative knowledge and problem scheme knowledge are excellent predictors of problem solving performance. However, a detailed analysis shows that the first knowledge type is more typical for low achievers (novices) in physics problem solving whereas the second type is predominately used by high achievers (experts). Regarding types and qualities of knowledge and their relations to problem solving, the results of a multidimensional scaling analysis (MDS) indicate that two dimensions of knowledge can be distinguished. On the extreme limits of the first dimension, which could be named “problem solving relevance vs. structure of discipline”, are the types of knowledge and the qualities of knowledge, respectively. The second dimension of knowledge could be named “single knowledge elements vs. organised knowledge units”. There are types of knowledge as well as qualities of knowledge distributed along this dimension. Consequences of these results for improving physics education are discussed.  相似文献   

9.
The presentation of pre-sliced specimens is a frequently used method in the laboratory teaching of cross-sectional anatomy. In the present study, a new teaching method based on a hands-on slicing activity was introduced into the teaching of brain, heart, and liver cross-sectional anatomy. A randomized, controlled trial was performed. A total of 182 third-year medical students were randomized into a control group taught with the prosection mode (pre-sliced organ viewing) and an experimental group taught with the dissection mode (hands-on organ slicing). These teaching methods were assessed by testing the students' knowledge of cross-sectional specimens and cross-sectional radiological images, and analyzing students' feedback. Using a specimen test on three organs (brain, heart, and liver), significant differences were observed in the mean scores of the control and experimental groups: for brain 59.6% (±14.2) vs. 70.1% (±15.5), (P < 0.001, Cohen's d = 0.17); for heart: 57.6% (±12.5) vs. 75.6% (±15.3), (P < 0.001, d = 0.30); and for liver: 60.4% (±14.5) vs. 81.7% (±14.2), (P < 0.001, d = 0.46). In a cross-sectional radiological image test, better performance was also found in the experimental group (P < 0.001). The mean scores of the control vs. experimental groups were as follows: for brain imaging 63.9% (±15.1) vs. 71.1% (±16.1); for heart imaging 64.7% (±14.5) vs. 75.2% (±15.5); and for liver imaging 61.1% (±15.5) vs. 81.2% (±14.6), respectively. The effect sizes (Cohen's d) were 0.05, 0.23, and 0.52, respectively. Students in the lower tertile benefited the most from the slicing experiences. Students' feedback was generally positive. Hands-on slicing activity can increase the effectiveness of anatomy teaching and increase students' ability to interpret radiological images.  相似文献   

10.

Resveratrol (3,5,4'-trihydroxystilbene, RSV) has been widely used in mammalian cells, but whether it can be used during freezing boar semen is still unknown. The effects of RSV treatment during boar semen freezing on its anti-freezing ability, apoptosis, and possible apoptotic pathways were observed in this study. Sperm motility, mitochondrial membrane potential (ΔΨm), adenosine triphosphate (ATP) content, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL)-positive apoptotic state, and messenger RNA (mRNA) expression levels of apoptotic genes involved in different apoptotic pathways after freezing with or without RSV treatment were tested. The results showed that: (1) Compared with fresh sperm, the motility, normal acrosome rate, and plasma membrane integrity rate of frozen boar sperm decreased significantly (P<0.05), and RSV did not significantly increase the sperm motility (0.44 vs. 0.40, P>0.05), but it did significantly improve the normal acrosome rate (57.65% vs. 47.00%, P<0.05) and plasma membrane integrity rate (46.67% vs. 38.85%, P<0.05). (2) After freezing, most boar sperm showed low mitochondrial ΔΨm. RSV treatment could increase the rate of high mitochondrial ΔΨm of boar sperm. (3) RSV treatment significantly decreased reactive oxygen species (ROS) levels (58.65% vs. 88.41%, P<0.05) and increased the ATP content (0.49 μmol/L vs. 0.25 μmol/L, P<0.05) of boar sperm during freezing. (4) The apoptotic rate of the freezing group (80.41%) with TUNEL detection increased significantly compared to the fresh group (9.70%, P<0.05), and RSV treatment greatly decreased the apoptotic rate (68.32%, P<0.05). (5) Real-time polymerase chain reaction (RT-PCR) showed that not only the genes from the death receptor-mediated apoptotic pathway (tumor necrosis factor-α (TNF-α), Fas ligand (FasL), and Caspase-8), but also the genes from the mitochondria-mediated apoptotic pathway (manganese superoxide dismutase (MnSOD), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and Caspase-9) were both significantly changed after freezing. RSV treatment during freezing greatly changed their expression levels. Although RSV treatment during boar semen freezing did not significantly increase motility after thawing, it still played an efficient antioxidant role, which could enhance the mitochondrial function and decrease the apoptotic level induced by both the death receptor- and mitochondria-mediated apoptotic pathways.

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11.
Several scholars have suggested the introduction of an environmental literacy requirement into the curricula of Non-Environmental Science disciplines in tertiary institutions of the world as a “greening” strategy for fostering global environmental stewardship necessary for enhancing understanding and collaboration in tackling the major environmental risks facing our global village today. However, there is no study on students’ opinion on this issue. This study was therefore initiated to 1) evaluate the opinion of undergraduate students on the introduction of a worldwide environmental literacy into the curricula of Non-Environmental science majors as a graduation requirement; and 2) identify any possible demographic differences in opinions among the student subjects polled. We sought the opinion of 800 undergraduates from African, North American and European universities on the subject and 99% responded. The result showed that a majority (67%) of them supported the worldwide environmental literacy requirement and those already trained were significantly (P < 0.0001) more likely to support it than those untrained. Students from developing countries were significantly (P < 0.0001) more likely to support it than those from developed countries; similarly students in the Arts’ disciplines were more likely to support it than Non-Arts’ students as a group. However, no significant differences were observed between students from Francophone versus Anglophone countries; Social Sciences versus Non-Social Sciences majors and between Education versus Non-Education majors. Some similarities were observed between the opinion of university-age students in this study and 15-year old secondary school students from two major international surveys (Research on Science Education-ROSE, and Program for International Student Assessment-PISA) on science education; further studies comparing these two categories of students is suggested. The need for all professionals to be literate about the science of their surroundings was the most identified reason for supporting the literacy requirement by the students polled. The results of this study thus provide evidence of support by students in the on-going paradigm shift towards “greening” the curricula of tertiary institutions and thus reinforces its implementation by leaders of academe and policy makers worldwide.  相似文献   

12.
Two experiments examined the effects of a multimedia technology referred to as “Time Compressed Animated Delivery” (TCAD), on student learning in a junior-level reproductive physiology course. In experiment 1, participating students received one of two presentations of the same instructional material: TCAD and a lecture captured on video. At the completion of each presentation a test was administered and group mean test scores computed and compared. The results were statistically significant (df = 362, t = 10.623, p < 0.05), favoring the TCAD treatment group. The effect size estimate was 1.14. In experiment 2, student learning from three groups were compared on the same reproductive physiology unit used in experiment 1: (1) TCAD, (2) TCAD without the 3-D component, and (3) video-lecture. After removal of three poor functioning items, a one-way analysis of variance was computed. The results were statistically significant (df = 2, F = 2.351, p < 0.10). Results of post hoc comparisons showed that differences in mean test scores between the TCAD and control groups were statistically significant (p < 0.05). The effect size estimate was 0.25. These findings provide preliminary evidence for use of TCAD.  相似文献   

13.
Objective: To investigate the relationships between endothelial nitric oxide synthases (eNOS) G894T and 27 bp-variable number tandem repeat (VNTR) gene polymorphisms and osteoporosis in the postmenopausal women of Chinese Han nationality. Methods: In the present study, 281 postmenopausal women from Xi'an urban area in West China were recruited, and divided into osteoporosis, osteopenia, and normal groups according to the diagnostic criteria of osteoporosis proposed by World Health Organization (WHO). The bone mineral density (BMD) values of lumbar vertebrae and left hips were determined by QDR-2000 dual energy X-ray absorptiometry. Blood samples were tested for plasma biochemical indicators including testosterone, estradiol, calcitonin, osteocalcin, and procollagen type I amino-terminal propeptide by enzyme-linked immunosorbent assay (ELISA), tartrate-resistant acid phosphatase by spectrophotometric method, and the content of nitric oxide by Griess method. Genome DNA was extracted from whole blood, and G894T polymorphism of eNOS gene was analyzed by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and 27 bp-VNTR polymorphism of eNOS gene was genotyped by PCR method. Then the relationships between genotypes and biochemical indicators, genotypes and osteoporosis, and haplotypes and osteoporosis were analyzed. Results: The average BMD values of the femoral neck, ward's triangle and lumbar vertebrae 1~4 (L1~L4) in the subjects with T/T genotype in eNOS G894T locus were significantly higher than those in the subjects with G/T and G/G genotypes (P<0.05). The average BMD of the femoral neck in the subjects with a/a genotype of eNOS 27 bp-VNTR locus was evidently higher than that in the subjects with b/b genotype (P<0.05). The plasma testosterone and osteocalcin concentrations in the subjects of eNOS G894T G/T genotype were evidently higher than those in the subjects of other genotypes (P<0.05); the plasma estradiol concentration in the subjects of eNOS 27 bp-VNTR a/a genotype was obviously higher than that in the subjects of b/b genotype (P<0.01). eNOS G/G homozygous frequencies in osteoporosis women, osteopenia women, and normal women were 85.37%, 76.38%, and 83.87%, respectively (P>0.05). 0% osteoporosis woman, 0.79% osteopenia women, and 3.23% normal women were eNOS a/a homozygous (P<0.05). The frequencies of eNOS 27 bp-VNTR a allele were 5.33% in the osteoporosis group, 10.24% in the osteopenia group, and 16.13% in the normal group (P<0.05, odds ratio (OR)=0.29, 95% confidence interval (CI)=0.11~0.77), suggesting that a/a genotype and a allele might have protective effects on osteoporosis. The haplotype analysis showed that G-b was 87.7% (214/244) in the osteoporosis group (P<0.05, OR=2AS, 95% CI=1.18~5.18). G-a was 5.3% (13/244) in the osteoporosis group (P<0.05, OR=0.29, 95% CI=0.11~0.77). G-b was a risk factor for osteoporosis, and G-a a protective factor. Conclusion: eNOS G894T G/T genotype influenced the plasma testosterone and osteocalcin concentrations, and T/T genotype influenced BMD. eNOS 27 bp-VNTR a/a genotype increased plasma estradiol concentration to have a protective effect on osteoporosis.  相似文献   

14.
The synthetic cadaver is a high-fidelity model intended to replace or supplement other anatomy learning modalities. Academic attainment and student perceptions were examined in an undergraduate human anatomy course using a combination of plastic models and synthetic cadavers to learn lower body anatomy (“Experimental group”), compared to a Historical group who used only plastic models. Grades on an upper body test, for which both groups used only plastic models, were compared to ensure that no academic differences existed between groups (P = 0.7653). Students in the Experimental group performed better on the lower body test for which they used both plastic models and synthetic cadavers (median = 73.8% (95% CI: 72.0%-75.0%) compared to the Historical group (70.1% (95% CI: 68.3%-70.7%), P < 0.0001); however, less than half of students (49%) attributed this to the synthetic cadavers. Students' perception of laboratory resources (P < 0.0001) and learning experience (P < 0.0001) both improved with the addition of synthetic cadavers compared to using only plastic models, and 60% of students in the Experimental group agreed that the synthetic cadavers would be a key reason that they would choose that institution for undergraduate studies. This investigation showed improved student grades when plastic models and synthetic cadavers were combined, in addition to improved student perceptions of the learning experience. Results of the student questionnaires also suggested that although synthetic cadavers carry a notable up-front cost, they may be a useful recruitment tool for institutions.  相似文献   

15.
Within the sphere of contemporary social sciences, the terms “modernity,” “post-modernity” and “globalization” have penetrated, as the core concepts, into various fields of social sciences in a logical way. In constituting the concept of “modernity,” sociology of education develops the educational theory, as sociological theory does, into a “grand narrative” and “foundationalist” theory; the contribution of post-modernity is pluralism and self-examination in an attempt to transcend modernity. Globalization, a kind of expanded modernity, makes education sociologists broaden their perspective from single and traditional “nationality,” “society” and “nation” to an international society and even to the global society, which has broken through the research paradigm of modernity with ethnocentrism, anthropocentrism and Euro-centrism. These changes have required urgent constitution of the conceptions and theoretical frameworks of sociology of education to be applied on a global level. __________ Translated from Peking University Education Review, 2006 (1)  相似文献   

16.
This article looks at how Ted Hughes’ poetry for children developed over more than 30 years of publication. It traces the movement from his earlier, more conventional rhyming poems, such as Meet My Folks! (1961) and Nessie the Mannerless Monster (1964), to the mature, free verse “animal poems” for older readers of Season Songs (1976c), Under the North Star (1981) and the “farmyard fable” What is the Truth? (1984). The article argues that the later lyrical poems for younger readers where Hughes returned to rhyme, The Cat and the Cuckoo (1987) and The Mermaid’s Purse (1993), represent an undervalued final phase of Hughes’ work for children which is rarely discussed by critics. The discussion considers Hughes’ changing attitude to the concept of the “children’s poet” at different periods of his career. Reference is made throughout to Hughes’ own writing about children and poetry, such as Poetry in the Making (1967), and to parallel developments in his poetry for adults.  相似文献   

17.
Several different pharmacological effects have been described for Nigella sativa (Siah-Daneh), including an anti-inflammatory effect. In the present study, the effect of the extract of N. sativa on lung pathology and blood interleukin-4 (IL-4) and interferon-γ (IFN-γ) of sensitized guinea pigs was examined. Three groups (n=8 for each group) of guinea pigs sensitized to ovalbumin (OA) were given drinking water alone, and drinking water containing low and high concentrations of the plant extract, respectively. The animals of the control group (n=8) were treated with saline instead of OA and were given drinking water. The pathological changes of the lung, including infiltration of eosinophils and lymphocytes, local epithelial necrosis, the presence of oedema, thickening of the basement membrane, smooth muscle layer hypertrophy, mucosal secretion, and the presence of mucosal plug, and blood IL-4 and IFN-γ of sensitized guinea pigs were evaluated. The lungs of the sensitized group showed significant pathological changes (P<0.001). Blood IL-4 and IFN-γ were increased in sensitized animals compared to the controls (P<0.01 and P<0.001, respectively). Treatment of sensitized animals with the extract led to a significant decrease in pathological changes of the lung (P<0.01 to P<0.001), except for the oedema in the sensitized group treated with low concentration of the extract, but an increased IFN-γ. These results confirm a preventive effect of N. sativa extract on lung inflammation of sensitized guinea pigs.  相似文献   

18.
This Participatory Action Research (PAR) project worked with four active street life oriented U. S. Born African men, to document how a community sample of street life oriented U. S. Born African men between the ages of 16–65, frame and use “street life” as a Site of Resiliency (Payne, Dissertation, 2005; Journal of Black Psychology 34(1):3–31, 2008). Qualitative data was collected in the form of 20 individual and two group interviews. These data reveal an inter-generational, conceptualization and use, of the term “street love” in street life oriented U. S. born African men. Also, these data reveal that notions of “street love” extend out a critique of community professionals (e.g., community researchers/interventionists, social workers, etc.) as being unable and unwilling to produce “real help” in the local community. Examples of street love, revealed in the study, include the men offering advice/counsel, money or “free turkeys” during Thanksgiving to one another as well as other members of the local community. Results support Payne’s (2005) three-dimension conceptualization of “street love”: (1) individual, (2) group and (3) communal level expressions of “street love”.
Yasser Arafat PayneEmail:
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19.
Shivam Kumar 《Resonance》2007,12(9):25-39
Are there perfect squares which on division by 7 leave remainder 3? Are there perfect squares which on division by 3 leave remainder 7? (A “remainder of 7” on division by 3 is the same as a remainder of 1.) The answers: ‘NO’ and ‘YES’, respectively. These facts are stated by number theorists as follows: 3 is a quadratic non-residue modulo 7; 7 is a quadratic residue modulo 3. The notion of quadratic residue is far reaching, and the key theorem here is the Law of Quadratic Reciprocity, first stated by Euler in 1783, but without proof, and first proved by Gauss, in 1796. The theorem is easy to state but is mysterious, as it reveals a connection between two questions that appear unconnected. Let p, q be distinct odd primes; then the questions are: “Is p a quadratic residue modulo q?” and “Is q a quadratic residue modulo p?” Gauss had a high regard for this result and called it Theorema Aureum, the Golden Theorem. Though it has been proved in many different ways, it retains its mystery. In this two part article we give three proofs of the theorem. The first one, described in this part, is based on group theory.  相似文献   

20.
The present study examined continuity of learning between face-to-face and online environments in a “blended” professional development program designed for 16 physics teachers. The program had nine face-to-face meetings as well as continuous online exchanges between them through a website. The program focused on “knowledge integration” (KI) innovative activities in physics classes using an “evidence-based” approach: The teachers implemented the activities, collected and analyzed data about their practice and their students’ learning, and reflected on the evidence with their peers. Five reflective tools were used to promote continuity: Your Comments, Hot Polls, Smashing Sentences, Hot Reports, and Mini Research. Continuity was assessed with regard to the ideas discussed by the teachers and the reasoning patterns that they employed. Analysis of the online exchanges in relation to teachers’ face-to-face discourse revealed that the teachers discussed the same ideas (KI, evidence and learner-centered pedagogies), employed the same reasoning patterns (e.g., forming generalizations), and extended ideas in re-visitation. The online and face-to-face environments played different and complementary roles in the teachers’ learning. This study shows that appropriate use of an online environment in a blended program can lead to a continuous course of learning and can transform a “9 once-a-month-meetings” workshop into a “9-month” workshop.  相似文献   

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