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排序方式: 共有190条查询结果,搜索用时 31 毫秒
1.
G Hendrickson R K Anderson P D Clayton J Cimino G M Hripcsak S B Johnson M McCormack S Sengupta S Shea R Sideli 《M.D. computing : computers in medical practice》1992,9(1):35-42
Over the past seven years, Columbia-Presbyterian Medical Center has been planning and implementing an integrated academic information management system. Accomplishments to date include establishing an institutional information architecture, installing a campus-wide network of workstations, recruiting the staff needed to develop and implement the system, and developing various applications. This paper presents the rationale and steps involved in these accomplishments, as well as data on use of the system so far. 相似文献
2.
Paul McCormack 《电子设计技术》2005,12(2):77-78
欠采样或违反奈奎斯特(Nyquist)准则是ADC应用上经常使用的一种技术。射频(RF)通信和诸如示波器等高性能测试设备就是其中的一此实例。在这个“灰色”地带中经常出现一些困惑,如是否有必要服从Nyquist准则,以获取一个信号的内容。对于Nyquist和Shannon定理的检验将证明; 相似文献
3.
4.
NC Day PJ Shaw AL McCormack PJ Craig W Smith R Beattie TL Williams SB Ellis PG Ince MM Harpold D Lodge SG Volsen 《Canadian Metallurgical Quarterly》1996,71(4):1013-1024
The distribution of voltage-dependent calcium channel subunits in the central nervous system may provide information about the function of these channels. The present study examined the distribution of three alpha-1 subunits, alpha 1A, alpha 1B and alpha 1E, in the normal human hippocampal formation and parahippocampal gyrus using the techniques of in situ hybridization and immunocytochemistry. All three subunit mRNAs appeared to be similarly localized, with high levels of expression in the dentate granule and CA pyramidal layer. At the protein level, alpha 1A, alpha 1B and alpha 1E subunits were differentially localized. In general, alpha 1A-immunoreactivity was most intense in cell bodies and dendritic processes, including dentate granule cells, CA3 pyramidal cells and entorhinal cortex pre-alpha and pri-alpha cells. The alpha 1B antibody exhibited relatively weak staining of cell bodies but stronger staining of neuropil, especially in certain regions of high synaptic density such as the polymorphic layer of the dentate gyrus and the stratum lucidum and radiatum of the CA regions. The alpha 1E staining pattern shared features in common with both alpha 1A and alpha 1B, with strong immunoreactivity in dentate granule, CA3 pyramidal and entorhinal cortex pri-alpha cells, as well as staining of the CA3 stratum lucidum. These findings suggest regions in which particular subunits may be involved in synaptic communication. For example, comparison of alpha 1B and alpha 1E staining in the CA3 stratum lucidum with calbindin-immuno-reactivity suggested that these two calcium channels subunits may be localized presynaptically in mossy fibre terminals and therefore may be involved in neurotransmitter release from these terminals. 相似文献
5.
MS Lefcoe GA Fox DJ Leasa RK Sparrow DG McCormack 《Canadian Metallurgical Quarterly》1994,105(3):885-887
Sixty-six supine portable chest radiographs done on the day of bronchoscopy in 62 critical care unit patients suspected of having pneumonia were examined in a blinded fashion by two radiologists. Quantitative culture results obtained from protected brush catheter (PBC) specimens were compared with chest radiograph scores. For one observer, the sensitivity of the chest radiograph for predicting the presence of positive culture results was 0.60, specificity was 0.29, overall agreement was 0.41, positive predictive value was 0.34, and negative predictive value was 0.55. For the second observer, the values were as follows: sensitivity, 0.64; specificity, 0.27; overall agreement, 0.41; positive predictive value, 0.35; and negative predictive value, 0.55. The kappa statistic was calculated at 0.27 indicating marginal interobserver reproducibility. We conclude the portable chest radiograph in the critical care setting is not accurate in predicting the presence of pneumonia when the diagnosis is based on quantitative cultures obtained from protected brush catheter specimens. 相似文献
6.
Four experiments examined children's ability to reason about the causal significance of the order in which 2 events occurred (the pressing of buttons on a mechanically operated box). In Study 1, 4-year-olds were unable to make the relevant inferences, whereas 5-year-olds were successful on one version of the task. In Study 2, 3-year-olds were successful on a simplified version of the task in which they were able to observe the events although not their consequences. Study 3 found that older children had difficulties with the original task even when provided with cues to attend to order information. However, 5-year-olds performed successfully in Study 4, in which the causally relevant event was made more salient. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
Creating and Rendering Convolution Surfaces 总被引:6,自引:0,他引:6
Implicit surfaces obtained by convolution of multi-dimensional primitives with some potential function, are a generalisation of popular implicit surface models: blobs, metaballs and soft objects. These models differ in their choice of potential function but agree upon the use of underlying modelling primitives, namely, points. In this paper a method is described for modelling and rendering implicit surfaces built upon an expanded set of skeletal primitives: points, line segments, polygons, arcs and planes. An analytical solution to the convolution is described. This solution offers a more accurate and robust representation of the resultant implicit surface than previous methods. An algorithm for ray-tracing the surfaces formed through convolution of any combination of these primitives is also outlined. 相似文献
8.
Elvev?g Brita; Brown Gordon D. A.; McCormack Teresa; Vousden Janet I.; Goldberg Terry E. 《Canadian Metallurgical Quarterly》2004,113(4):509
Patients with schizophrenia display numerous cognitive deficits, including problems in working memory, time estimation, and absolute identification of stimuli. Research in these fields has traditionally been conducted independently. We examined these cognitive processes using tasks that are structurally similar and that yield rich error data. Relative to healthy control participants (n = 20), patients with schizophrenia (n = 20) were impaired on a duration identification task and a probed-recall memory task but not on a line-length identification task. These findings do not support the notion of a global impairment in absolute identification in schizophrenia. However, the authors suggest that some aspect of temporal information processing is indeed disturbed in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
David Kok Devinder Yadav Emanuele Sortino Scott J. McCormack Kuo-Pin Tseng Waltraud M. Kriven Rishi Raj Martha L. Mecartney 《Journal of the American Ceramic Society》2019,102(2):644-653
In situ X-ray diffraction measurements at the Advanced Photon Source show that α-Al2O3 and MgAl2O4 react nearly instantaneously and completely, and nearly completely to form single-phase high-alumina spinel during voltage-to-current type of flash sintering experiments. The initial sample was constituted from powders of α-Al2O3, MgAl2O4 spinel, and cubic 8 mol% Y2O3-stabilized ZrO2 (8YSZ) mixed in equal volume fractions, the spinel to alumina molar ratio being 1:1.5. Specimen temperature was measured by thermal expansion of the platinum standard. These measurements correlated well with a black-body radiation model, using appropriate values for the emissivity of the constituents. Temperatures of 1600-1736°C were reached during the flash, which promoted the formation of alumina-rich spinel. In a second set of experiments, the flash was induced in a current-rate method where the current flowing through the specimen is controlled and increased at a constant rate. In these experiments, we observed the formation of two different compositions of spinel, MgO•3Al2O3 and MgO•1.5Al2O3, which evolved into a single composition of MgO•2.5Al2O3 as the current continued to increase. In summary, flash sintering is an expedient way to create single-phase, alumina-rich spinel. 相似文献
10.
Garrett Melia Jonathan Moghal Craig Hicks Mohamed Oubaha Declan McCormack Brendan Duffy 《Journal of Coatings Technology and Research》2016,13(6):1083-1094
This research article reports on the response of various hybrid sol–gel materials when applied as coatings to pre-treated bare AA2024 substrates, to mechanical indentation and cyclic thermal stimuli, in order to determine their usefulness in aeronautical applications. Three groups of hybrid sol–gel-coated samples were prepared using various organosilanes and transition metal oxides. The characterization of the materials revealed that the presence of the organic functionalities, especially the methacrylate group, has a noticeable effect on the mechanical response of the hybrid coatings, in particular their flexibility. The presence of methacrylate group in the cured material gives it ability to flex which influenced the thermal fatigue characteristics of the coatings which are able to withstand the cyclic temperature regimes of 82 ± 3 to ?37 ± 3°C over 25 2 h cycles. This capability to maintain substrate protection is reflected in the corrosion resistance of the coatings as measured using electrochemical impedance spectroscopy and accelerated exposure testing. This result is important, as it shows that hybrid sol–gel materials can be used in applications where protecting a metal or ally substrate is paramount, especially in thermally volatile environments. 相似文献