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101.
JT Marais 《Canadian Metallurgical Quarterly》1998,53(3):111-119
The Mini-Mental-State Examination (MMSE) is widely used as a screening tool for dementia in epidemiological studies. Its applicability in population-based studies is nevertheless limited by its low specificity. The effect of age and educational level have been usually ignored when cut-off scores have been selected. The aim of this study was to evaluate the effect of age and educational level on the MMSE scores in a representative sample of subjects older than 70 and provide adjusted normalised data according to these two variables, after excluding subjects with dementia or cognitive decline. Population-based, cross-sectional and longitudinal study of a representative cohort of 1367 subjects older than 70. All subjects with suspected dementia or cognitive decline received a neurological evaluation where clinical and etiological diagnosis were established. Normal MMSE scores, as defined by the 10th percentile, varied significantly across age and educational level groups. Exclusion of demented or cognitively declined patients from the reference population reduced the variability and "range of normality", but this remained excessively high in the older and less educated groups. The use of different cut-off points for each age and educational level groups may improve the specificity and applicability of the MMSE in population-based epidemiological studies. However, the wide amplitude of the range of normality suggests that different approaches, other than this vibariate analysis, may prove more adequate in the selection of cut-off scores for the MMSE. 相似文献
102.
P So JT Francis TI Netoff BJ Gluckman SJ Schiff 《Canadian Metallurgical Quarterly》1998,74(6):2776-2785
A new nonlinear dynamical analysis is applied to complex behavior from neuronal systems. The conceptual foundation of this analysis is the abstraction of observed neuronal activities into a dynamical landscape characterized by a hierarchy of "unstable periodic orbits" (UPOs). UPOs are rigorously identified in data sets representative of three different levels of organization in mammalian brain. An analysis based on UPOs affords a novel alternative method of decoding, predicting, and controlling these neuronal systems. 相似文献
103.
Absolute figure measurements with a liquid-flat reference 总被引:2,自引:0,他引:2
We describe a variation of the liquid-flat technique fordetermining the absolute flatness of a 240-mm-diameter optical surfaceto an accuracy better than 1/100lambda in both its horizontal(three-point support) and vertical orientations. Using theappropriate mathematics to calculate the surface deformation of a diskdue to gravity, we achieved verification of the method by comparingmeasurements carried out on a pair of optical flats and a liquidreference surface. 相似文献
104.
Industry has become aware of the problem of severe generator damage due to stator ground faults. It has been suggested that, to prevent this damage, the practices employed for neutral grounding should be changed. This paper provides an analytical perspective on this problem and suggests that the real issue is the manner in which the neutral of the generator itself is grounded 相似文献
105.
Powell I 《Applied optics》1996,35(31):6190-6194
A design study was undertaken on an infrared, 3-5-μm, panoramic optical system for a particular monitoring application. The different types of systems investigated covered the conventional fish-eye lens system, a panoramic block arrangement, and a new type of configuration based on a panoramic shell. Examples of these systems are included, and their advantages and disadvantages are discussed. 相似文献
106.
T. Takada J. D. Mackenzie M. Yamane K. Kang N. Peyghambarian R. J. Reeves E. T. Knobbe R. C. Powell 《Journal of Materials Science》1996,31(2):423-430
Non-linear optical properties of CdS quantum dots embedded in the sol-gel derived Na2O-B2O3-SiO2x3 glass matrix have been studied using nanosecond degenerate four-wave mixing (DFWM), pump-probe experiments, and time-resolved subpicosecond DFWM measurements. The concentration of CdS microcrystallites was varied from 1.4 to 10.2 wt% while the particle size was controlled to be in the range of 3–6 nm in diameter so that the confinement effects can be realized. The third-order susceptibility, 3, was determined to be of the order of 10–7-10–6 e.s.u. near the resonant wavelength between 450 and 470 nm by the nanosecond DFWM and pump-probe experiments, and of the order of 10–11-10–10 e.s.u. at the off-resonant wavelength, 580 nm, by a time-resolved DFWM measurement with 400 fs laser pulse. The decay time changed from 0.5 to 50 picoseconds as a function of the size, size distribution and number density of CdS microcrystallites in the glasses. Photodarkening reduced the optical non-linearity of the melt-quenched samples by a factor of 20, while it had no appreciable effect on that of the sol-gel derived samples.[/p] 相似文献
107.
JW Lynch GA Kaplan RD Cohen J Tuomilehto JT Salonen 《Canadian Metallurgical Quarterly》1996,144(10):934-942
Much remains to be understood about how low socioeconomic status (SES) increases cardiovascular disease and mortality risk. Data from the Kuopio Ischemic Heart Disease Risk Factor Study (1984-1993) were used to estimate the associations between acute myocardial infarction and income, all-cause mortality, and cardiovascular mortality in a population-based sample of 2,272 Finnish men, with adjustment for 23 biologic, behavioral, psychologic, and social risk factors. Compared with the highest income quintile, those in the bottom quintile had age-adjusted relative hazards of 3.14 (95% confidence interval (CI) 1.77-5.56), 2.66 (95% CI 1.25-5.66), and 4.34 (95% CI 1.95-9.66) for all-cause mortality, cardiovascular mortality, and AMI, respectively. After adjustment for risk factors, the relative hazards for the same comparisons were 1.32 (95% CI 0.70-2.49), 0.70 (95% CI 0.29-1.69), and 2.83 (95% CI 1.14-7.00). In the lowest income quintile, adjustment for risk factors reduced the excess relative risk of all-cause mortality by 85%, that of cardiovascular mortality by 118%, and that of acute myocardial infarction by 45%. These data show how the association between SES and cardiovascular mortality and all-cause mortality is mediated by known risk factor pathways, but full "explanations" for these associations will need to encompass why these biologic, behavioral, psychologic, and social risk factors are differentially distributed by SES. 相似文献
108.
JD Reveille GS Alarcón SE Fowler SR Pillemer R Neuner DO Clegg IS Mikhail DE Trentham JC Leisen G Bluhm SM Cooper H Duncan M Tuttleman SP Heyse JT Sharp B Tilley 《Canadian Metallurgical Quarterly》1996,39(11):1802-1807
OBJECTIVE: To examine the effect of alleles encoding the "shared"/"rheumatoid" epitope on rheumatoid arthritis (RA) disease severity in patients who participated in the minocycline in RA (MIRA) trial. METHODS: Of 205 patients with a week-48 visit, blood was available for typing of HLA-DRB1 and HLA-DQB1 in 174 (85%) and successfully completed in 169 (82%). Baseline erosions were used to assess disease severity and new erosions at the last visit served as a proxy for progression. RESULTS: At baseline, there was no association between the presence of erosive disease or rheumatoid factor status and the dose of rheumatoid epitope (homozygous, heterozygous, none) or the specific alleles identified. At the final visit, a gradient was observed for the 3 allelic subgroups (and their gene doses) in the occurrence of new erosions among the Caucasian placebo-treated, but not the minocycline-treated, patients. A treatment group/HLA-DR4 epitope interaction was demonstrated in multivariate analyses. Approximately two-thirds of African-American patients did not have the rheumatoid epitope. CONCLUSION: HLA-DRB1 oligotyping may be useful in predicting the progression of disease in some Caucasian patients. Our study corroborates the infrequency of the epitope among African-American patients with RA. 相似文献
109.
This paper addresses the non-preemptive single machine scheduling problem to minimize total tardiness. We are interested in
the online version of this problem, where orders arrive at the system at random times. Jobs have to be scheduled without knowledge
of what jobs will come afterwards. The processing times and the due dates become known when the order is placed. The order
release date occurs only at the beginning of periodic intervals. A customized approximate dynamic programming method is introduced
for this problem. The authors also present numerical experiments that assess the reliability of the new approach and show
that it performs better than a myopic policy. 相似文献
110.
Age-related changes in selective attention, inhibitory efficiency, and the ability to form new associations suggest that older adults may have greater difficulty with more complex and less comprehensible symbols. We examined comprehension of symbols varying in terms of ratings of familiarity, complexity, and comprehensibility, by younger (aged 18-35) and older (aged 55-70) adults. It was found that older adults have greater difficulty than younger adults in comprehending warning symbols and that accident scenario training improves comprehension. Regression analyses indicated that familiarity and comprehensibility were important in determining performance on the pre-training comprehension test by both younger and older adults. However, training eliminated the effects of stimulus characteristics for younger adults, while older adults' comprehension continued to be significantly influenced by comprehensibility. We suggest that symbol design incorporates cues to knowledge to facilitate the linkage between new knowledge (i.e. the warning symbol) and relevant knowledge in long-term memory. Statement of Relevance: Symbol characteristics play an important role in age-related differences in warning symbol comprehension. To optimise comprehension by older adults, symbols should have a clear relationship with areal-world referent. Alternatively, symbol design could incorporate cues to knowledge to facilitate the linkage between new knowledge and relevant knowledge in long-term memory. 相似文献