Zinc: what is its role in biology?     

Robert J.P. Williams 《Endeavour》1984,8(2):65-70

Zinc is as common as iron in biology. It is usually thought to be a trace element required only for catalysis. Here it is shown that the role of zinc is much more fundamental not only in catalysis but in inhibitory control. There may well be several such control elements—calcium, iron, manganese, magnesium, and zinc.  相似文献   

Text windows and phrases differing by discipline, location in document, and syntactic structure     

Robert M. Losee 《Information processing & management》1996,32(6):747-767

Knowledge of window style, content, location, and grammatical structure may be used to classify documents as originating within a particular discipline or may be used to place a document on a theory vs practice spectrum. This distinction is also studied here using the type-token ratio to differentiate between sublanguages. The statistical significance of windows is computed, based on the presence of terms in titles, abstracts, citations, and section headers, as well as binary-independent and inverse-document-frequency weightings. The characteristics of windows are studied by examining their within-window density and the S concentration, the concentration of terms from various document fields (e.g. title, abstract) in the fulltext. The rate of window occurrences from the beginning to the end of document fulltext differs between academic fields. Different syntactic structures in sublanguages are examined, and their use is considered for discriminating between specific academic disciplines and, more generally, between theory vs practice or knowledge vs applications-oriented documents.  相似文献   

Asymptotics and the Role of Minimal Models   总被引：2，自引：0，他引：2  

Batterman  Robert W. 《The British journal for the philosophy of science》2002,53(1):21-38

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Dynamic dictionary updating     

Robert G. Crawford 《Information processing & management》1977,13(4):235-245

A method for updating the dictionary in a dynamic information retrieval system is presented. It is shown that as a collection changes through addition and deletion of documents, the appropriate set of index terms may be determined without complete periodic regeneration of the dictionary. Results are presented for experiments involving a complete change in collection membership, with the dynamic dictionary updating methods shown to be effective.  相似文献   

Domesticating Computers and the Internet   总被引：1，自引：0，他引：1  

Jonathon N. Cummings  Robert Kraut 《The Information Society》2002,18(3):221-231

The people who use computers and the ways they use them have changed substantially over the past 25 years. In the beginning highly educated people, mostly men, in technical professions used computers for work, but over time a much broader range of people are using computers for personal and domestic purposes. This trend is still continuing, and over a shorter time scale has been replicated with the use of the Internet. This paper uses data from four national surveys to document how personal computers and the Internet have become increasingly domesticated since 1995 and to explore the mechanisms for this shift. Now people log on more often from home than from places of employment and do so for pleasure and for personal purposes rather than for their jobs. Analyses comparing veteran Internet users to novices in 1998 and 2000 and analyses comparing the change in use within a single sample between 1995 and 1996 support two complementary explanations for how these technologies have become domesticated. Women, children, and less well-educated individuals are increasingly using computers and the Internet and have a more personal set of motives than well-educated men. In addition, the widespread diffusion of the PC and the Internet and the response of the computing industry to the diversity in consumers has led to a rich set of personal and domestic services.  相似文献   

Evaluating the NASA small business innovation research program: preliminary evidence of a trade-off between commercialization and basic research     

Robert B Archibald  David H Finifter 《Research Policy》2003,32(4):605-619

In 1982, the Small Business Innovation Development Act established the small business innovation research (SBIR) program. This program reserves a percentage of federal agencies’ extramural R&D budgets for research projects conducted by small businesses. When this Act was reauthorized in 1992, the selection criteria for funding dramatically increased the likelihood of funding for projects that promised to lead to commercial success. Using data from a survey of the SBIR program award recipients at NASA Langley Research Center, we address three questions about this change: (i) was there a shift to projects with more commercial potential? (ii) did these projects experience higher rates of commercial success? and (iii) was there a reduction in basic research accompanying the increased commercial success? Our analysis suggests, the answer to all three of these questions is ‘yes’.  相似文献   

Theory of synchronous communications : J.J. Stiffler. 562 pages,diagrams, 6 x 9 in. Englewood Cliffs,New Jersey,Prentice-Hall, 1971. Price, $16.95 (approx. £6·55).     

Robert M. Gray 《Journal of The Franklin Institute》1973,295(2):182-183

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Three Cases of Lead Toxicity Associated with Consumption of Ayurvedic Medicines     

Raviraja A  Vishal Babu GN  Sehgal A  Saper RB  Jayawardene I  Amarasiriwardena CJ  Venkatesh T 《Indian journal of clinical biochemistry : IJCB》2010,25(3):326-329

Ayurveda is a traditional form of medicine used by majority of the Indians. Here we report three cases of lead toxicity, following intake of Ayurvedic medicines. Three patients presented with blood lead levels (BLLs) of 122.4, 115 and 42.8 μg/dl respectively at the time of hospitalization. The first case was chelated with D- penicillamine, the second with calcium disodium ethylene diamino tetra acetate (EDTA) and the third with environmental intervention and education. Associated Ayurvedic products were collected from patients and analyzed for metallic concentration. Cessation of Ayurvedic medication along with chelation, nutritional intervention and education, reduced the BLL to 27.4 μg/dl in the first case after 1 year, 21.1 μg/dl after 9 months in the second and 18.2 μg/dl after 6 months in the third case.  相似文献   

I Agree—Well,Mostly!     

Robert J. Sternberg 《Roeper Review》2017,39(4):246-249

In this essay, I reply to my five commentators in the October 2017 issue of the Roeper Review to my July 2017 article: “ACCEL: A New Model for Identifying the Gifted.” I respond to each in turn. I end with the question I believe most important for those of us interested in giftedness to confront at the present moment.  相似文献   

Why 3D Print? The 21st-Century Skills Students Develop While Engaging in 3D Printing Projects     

Torrey Trust  Robert W. Maloy 《学校用计算机》2017,34(4):253-266

The emergence of 3D printing has raised hopes and concerns about how it can be used effectively as an educational technology in school classrooms. This paper presents the results of a survey asking teachers from multiple grade levels and subject fields about the impact of 3D projects on student learning. Teachers were asked about the kinds of 3D projects they were doing with students and what skills or knowledge students were developing by participating in those projects. Participants reported that their students developed a number of skills while working on 3D printing projects, including 3D modeling, creativity, technology literacy, problem-solving, self-directed learning, critical thinking, and perseverance. Parallels between teacher-identified skills and widely cited lists of 21^st-century skills suggest that 3D projects are a promising approach to preparing students for life and work in a digital age.  相似文献