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951.
952.
This article examines the claim that the learning of a dynamic control task is mediated by a lookup table consisting of previously successful trials on the task. Consistent with the predictions of a lookup table, in 2 experiments participants tended to give the same response to situations in which they had previously been successful rather than unsuccessful. Further, in both experiments, participants' knowledge did not generalize to new dissimilar situations, unless the dynamic control task was governed by a highly salient rule. A version of G. Logan's (1988) instance theory, which assumes that participants store each successful response as a separate instance linking the situation to the response, was able to quantitatively match a range of measures of participants' performance with 1 free parameter, except in the case in which the control task was governed by a salient rule. In a complementary way, an alternative rule-based model could only match participants' performance when the control task was governed by a highly salient rule. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
953.
954.
I Contreras R San-Millán A Agustín-Barrasa J Pontón G Quindós 《Canadian Metallurgical Quarterly》1996,136(1):17-20
A clinical study was carried out in an attempt to assess the efficacy of a newly designed electric toothbrush compared to a conventional manual toothbrush using the American Dental Association's protocol for evaluating toothbrushes. An Oral-B 35 manual toothbrush, which served as the control, was compared to the Plaq & White125 electric toothbrush. Examinations were performed by two calibrated examiners at baseline, day 15 and day 30. Examinations included the gingival index, plaque index and bleeding index. Mean indices were calculated and compared between the two brushes using the repeated measures multiple analysis of variance. No statistically significant differences between the mean indices on the three examination days were observed following the use of the manual or the electric toothbrushes. The results of this study demonstrate that the electric toothbrush was numerically more effective than the manual toothbrush in reducing supragingival plaque levels, either before or after brushing, at each examination date compared to baseline plaque values. However, this difference was not statistically significant. This and other findings concluded that the Plaq & White toothbrush is comparable to the control ADA-accepted toothbrush. 相似文献
955.
T Forst A Pfützner P Kann B Schehler R Lobmann H Sch?fer J Andreas A Bockisch J Beyer 《Canadian Metallurgical Quarterly》1995,12(10):874-879
Alterations in bone metabolism in diabetes mellitus is a topic of special interest. Bone blood flow is increased in the distal limb of diabetic patients, which is believed to increase osteoclastic activity. We measure bone mineral density using dual-photon absorptiometry in the distal lower limb, the femoral neck, and the lumbar spine in 41 IDDM patients and in 30 control persons. In the diabetic group there was a 10% reduction of bone mineral density in the femoral neck (p < 0.01) and a 12% reduction in the distal limb (p < 0.001) compared with the control group. No significant difference was found in the lumbar spine (p = 0.22). Our data yield incidence for peripheral osteopenia in IDDM-patients, independent of any systemic bone disease such as osteoporosis. A link between decreased bone mineral density and diabetic neuropathy has been observed for the femoral neck (p < 0.001), but not for the distal limb or axial skeleton. Whether there is a common aetiological link or a casual connection between diabetic neuropathy and bone mineral density has still to be determined. 相似文献
956.
957.
As part of an 18-month carcinogenicity study, 680 Syrian hamsters (Mesocricetus auratus) received daily gavage doses of fenazaquin, an experimental miticide. Mortality associated with severe enteritis was noticed beginning when the hamsters were 4 months old and ranged from one to five deaths per month until the hamsters were about 10 months old, when 41 deaths occurred in a 1-month period. Ante- and postmortem findings were consistent with those reported for antibiotic-induced enteritis in hamsters. Clostridium difficile was isolated from 12 of the 13 samples of cecal contents analyzed. Toxin assays of C. difficile isolates collected from 11 affected animals were positive for both cyto- and enterotoxins. Daily oral administration of vancomycin hydrochloride at a dose of 20 mg/kg was initiated when the hamsters were about 10 months old. Deaths due to C. difficile enteritis were significantly decreased within 2 weeks, and treatment was continued for 3 months. A trial withdrawal period for a subset of 64 hamsters (approximately 16% of the total population) was initiated to evaluate survival after discontinuation of the antibiotic treatment. Clostridium difficile enteritis recurred within 2 weeks and caused 19 deaths during the next month; therefore, these hamsters were returned to daily vancomycin treatment for the remainder of the study. With the exception of severe gaseous distention of the ceca, which caused death in 17 (< 4% of the total population) of the affected hamsters, vancomycin treatment did not cause any major adverse effects.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
958.
959.
960.
Sustainable transport? 《Refocus》2002,3(4):34
As the pace of life in the 21st Century continues to increase dramatically, mobility is now one of the defining characteristics of most societies. This has lead to more and more cars and, unfortunately, more and more pollution. Some way of providing sustainable transport has to be found and alternative energy supplies such as wind and solar will undoubtedly play a major part in providing the power for any such solution. Urs Muntwyler and Frans Koch, respectively chair and secretary of the IEA group, provide an overview of the general sustainable energy supply options for transportation and the resource potential of various forms of renewable energy. 相似文献