Turning science to account: Chicago and the general science movement in secondary education, 1905-1920     

Rudolph JL 《Isis; an international review devoted to the history of science and its cultural influences》2005,96(3):353-389

In the second decade of the twentieth century a new subject appeared in American high schools, aimed at providing citizens with an understanding of the essential nature of scientific thinking. "General science," as it was called, was developed and promoted by an emerging class of professional educators who sought to offer a version of science that they believed would both excite public interest and prove useful in the everyday lives of the masses of students streaming into the rapidly expanding institution of secondary education. It was to be a course with real utility that would transcend the boundaries of the specialized, abstract disciplinary subjects like chemistry and physics-subjects with identities tied to the practices and standards of the colleges and universities, which had long exerted control over the content of secondary schooling. This essay recounts the origins of general science and, in particular, examines how the intellectual and material environment of the city of Chicago at the turn of the century influenced the course that was produced and widely adopted in school programs across the United States.  相似文献   

Diurnal variation in serum glucose,pyruvate, lactate and lactate dehydrogenase levels under different environmental temperatures     

S. K. Bansal  H. N. Pandey  A. Bansal  L. D. Joshi 《Indian journal of clinical biochemistry : IJCB》1992,7(2):179-184

Circadian rhythm of serum glucose, pyruvate, lactate and lactate dehydrogenase (LDH) was studied in normal healthy young volunteers at the onset (I Group, 7 cases) and peak (II Group, 8 cases) of winters in India with highly varied temperature. There was a significant difference, in the circadian rhythm of glucose, pyruvate and lactate dehydrogenase (LDH) of the two groups. A clockwise shift was observed in acrophase except in serum lactate, which is related to the energy demand in association with time qualified changes in diurnal activity of the individuals and change in photoperiod.  相似文献   

Identification of analytic signals     

L. Kazovsky  A. Zayezdny  E. Plotkin 《Journal of The Franklin Institute》1983,315(1):37-47

This paper is devoted to the identification of analytic signals and to find a solution to the following problem. Given a realization of an analytic signal, it is necessary to find the analytic function by which the signal is described. The proposed approach to this problem is based on relatively simple relationships existing between many analytic signals and their respective derivatives. These relationships are closely related to the properties of the dynamic systems which generate the signals under investigation. Simple identification procedures are described and tested by means of computer simulation.  相似文献   

广东科技期刊稿约中的审稿时间的调查和分析     

李明山  吕静 《中国科技期刊研究》2007,18(3):412-414

调查了广东部分科技期刊稿约中的审稿时间，发现其中存在一些问题亟待解决。解决问题的关键在于签订著作权合同。规范期刊社和作者之间的著作权关系，严格依法办事。  相似文献   

Environment and Policy Factors Shaping Global E-Commerce Diffusion: A Cross-Country Comparison   总被引：1，自引：0，他引：1  

Jennifer Gibbs  Kenneth L. Kraemer  Jason Dedrick 《The Information Society》2003,19(1):5-18

This article examines the key global, environmental and policy factors that act as determinants of e-commerce diffusion. It is based on systematic comparison of case studies from 10 countries--Brazil, China, Denmark, France, Germany, Mexico, Japan, Singapore, Taiwan, and the United States. It finds that B2B e-commerce seems to be driven by global forces, whereas B2C seems to be more of a local phenomenon. A preliminary explanation for this difference is that B2B is driven by global competition and MNCs that "push" e-commerce to their global suppliers, customers, and subsidiaries. This in turn creates pressures on local companies to adopt e-commerce to stay competitive. In contrast, B2C is "pulled" by consumer markets, which are mainly local and therefore divergent. While all consumers desire convenience and low prices, consumer preferences and values, national culture, and distribution systems differ markedly across countries and define differences in local consumer markets. These findings support the transformation perspective about globalization and its impacts. In terms of policy, the case studies suggest that enabling policies such as trade and telecommunications liberalization are likely to have the biggest impact on e-commerce, by making ICT and Internet access more affordable to firms and consumers, and increasing pressure on firms to adopt e-commerce to compete. Specific e-commerce legislation appears not to have as big an impact, although inadequate protection for both buyers and sellers in some countries suggests that mechanisms need to be developed to ensure greater confidence in doing business online.  相似文献   

Serum oestradiol in women with carcinomas of the breast and uterine cervix     

Amitabha Ray  Anil Kumar Bahadur  S. L. Dayalu Naik  Bhuvnesh Kumar Sharma 《Indian journal of clinical biochemistry : IJCB》2001,16(2):199-202

Endogenous oestrogens are thought to be involved in breast cancer, but few studies could show the direct relationship between hormones and pathological process of the disease. In the present study, oestradiol was estimated in the serum of pre-and postmenopausal breast cancer patients along with normal healthy controls and patients with carcinoma of the uterine cervix which is not dependent on oestrogens. Premenopausal patients with breast cancer showed higher levels of oestradiol as compared to premenopausal control women as well as cervical cancer patients. Whereas, no statistically significant differences were observed in serum oestradiol levels amongst postmenopausal groups of breast cancer, cervical cancer and normal women. The result of the study reflects the association of oestradiol as well as its difference in the pathological events of pre and postmenopausal breast cancer.  相似文献   

On the notions of ambiguity and information loss     

James L. Dolby 《Information processing & management》1977,13(1):69-77

One of the fundamental problems in information science is to distinguish various objects (such as books or journal articles) on the basis of associated values (such as authors and titles). Where the values fail to distinguish two distinct objects we say that the objects are ambigious under the given value assignment. To obtain a measure of ambiguity, it is only necessary to count the number of ways that the objects can be arranged for each set of ambiguous objects, multiply these counts and take logarithms. It is shown that such an approach leads to a measure in the formal sense and that the measure depends only on the definition of equality of values so that it can be simply extended to sets of values and ordered sets of values. It is also shown that it is possible to construct a function of ambiguity that one can call “information” and that the information loss that occurs when distinct values are grouped into equivalence classes (as in the use of search and sort keys) is also a measure. Finally, it is shown that ambiguity and information as here defined are directly related to Shannon's definition of “information” thus tieing this approach to that portion of information theory associated with the derivation of optimal distributions frequently used in information science models.  相似文献   

Design equations for citation retrieval systems: Their role in research and analysis     

I.L. Travis 《Information processing & management》1977,13(1):49-56

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Organo-metallics in organic synthesis. Vol. 1: By Ei-ichi Negishi. Pp. 532. Wiley,Chichester. 1980. £15.85     

J.L. Wardell 《Endeavour》1981,5(3):135-136

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Hyperlipidemia in guinea pigs induced by chronic vitamin C deficiency     

Praveen Sharma  P. K. Sharma D.Sc.  J. Pramod  L. K. Kothari  Rashmi Ranka  Sushma Sharma 《Indian journal of clinical biochemistry : IJCB》1989,4(1):62-64

Sixteen weeks of chronic vitamin C deficiency, induced in guinea pigs by restricted vitamin C intake, resulted in a marked increase in the serum total LDL- and VLDL- cholesterol, triglycerides and total lipids. HDL-cholesterol decreased resulting in a highly significant increase in LDL/HDL ratio. The results reconfirm that vitamin C deficiency causes changes in blood lipid profile which could promote atherogenesis.  相似文献