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121.
ME Kimerling WH Benjamin KH Lok G Curtis NE Dunlap 《Canadian Metallurgical Quarterly》1998,2(8):655-662
SETTING: Alabama State Tuberculosis Control Program, USA. OBJECTIVE: To combine molecular screening data with routine information to assess transmission of Mycobacterium tuberculosis and improve control efforts. DESIGN: Since January 1994, samples from tuberculosis cases statewide have been systematically analyzed by IS6110 restriction fragment length polymorphism (RFLP). All cases during 1994-1995 with a predominate RFLP pattern were evaluated and risk factors assessed. pTBN12 was used to evaluate a large cluster in the Birmingham-Jefferson County (BJC) area. RESULTS: Statewide, a common two-band pattern was found, named JH2 (99/566, 17.5%). The most important risk associated with this pattern was homelessness (odds ratio, 8.9; P < 0.001). In the BJC area, the homeless accounted for 29% (51/175) of new cases diagnosed during the study period. For the BJC homeless, there were 13 unique RFLP patterns, and JH2 was predominant (29/33, 88%) among three clusters. Secondary analysis of the homeless JH2 cluster revealed a large group that included 19 of 24 (79%) isolates analyzed. Compared with the BJC non homeless (n = 124), the homeless were younger (P < 0.001), of male gender (P < 0.001), black race (P = 0.002), and were heavy alcohol (P < 0.001) and non-injection drug (P = 0.001) users. CONCLUSIONS: By screening tuberculosis cases statewide, a common two-band RFLP pattern was identified. Its predominance is explained by an ongoing tuberculosis epidemic among Birmingham's homeless population, highlighting RFLP as a tool for population surveillance. The pattern differences observed by pTBN12 typing clearly demonstrate that the isolates might be related but are not clonal. 相似文献
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Demonstrates that if a transformation can be found that minimizes skew while tending to equate group variances, the power of the F test will be increased. Use of such transformations, while tending to correct violations of F-test assumptions, will result in greater power. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
125.
Kemery Edward R.; Dunlap William P.; Griffeth Rodger W. 《Canadian Metallurgical Quarterly》1988,73(4):688
A correction procedure is proposed for adjusting point-biserial correlations for attenuation produced by inopportune splits in the dichotomous variable. The correction procedure permits estimation of the point-biserial correlation that would have been seen had equal proportions been present. Monte Carlo simulation evidence is provided for the accuracy of the correction procedure. Also, an example is provided from the employee turnover literature to illustrate how the correction procedure may be used. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Zirconia stationary phases for extreme separations. 总被引:1,自引:0,他引:1
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Using a vertical-axis attritor, samples of (SnxCo1−x)60C40 for 0 ≤ x ≤ 0.7 have been prepared in increments of Δx = 0.1. The effect of Sn content on the structure and performance of the Sn-Co-C nanocomposites was examined by X-ray diffraction (XRD), 119Sn Mössbauer effect spectroscopy and electrochemical methods. XRD shows a diffraction pattern characteristic of a nanostructured material having amorphous CoSn grains in a carbon matrix for x = 0.5. Broad Bragg peaks of Co3C, SnCo3C0.7 and CoSn2 were observed for samples with 0 ≤ x ≤ 0.1, 0.1 ≤ x ≤ 0.4 and 0.5 < x ≤ 0.7, respectively. 119Sn Mössbauer effect spectroscopy shows the presence of an amorphous CoSn component in samples with 0.3 ≤ x ≤ 0.6. Samples with a large amount of the SnCo3C0.7 phase showed small capacity for lithium. Therefore, SnCo3C0.7 is best described as an inactive phase. The sample with x = 0.7 shows the highest specific capacity (about 600 mAh/g) of all samples prepared but exhibited poor capacity retention after cycle 45. Excellent charge-discharge capacity retention, reasonable specific capacity (>450 mAh/g) along with stable differential capacities were observed for samples near x = 0.5. 相似文献
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