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排序方式: 共有1933条查询结果,搜索用时 15 毫秒
991.
KG Saag BN Doebbeling JE Rohrer S Kolluri R Peterson ME Hermann RB Wallace 《Canadian Metallurgical Quarterly》1998,36(7):965-976
OBJECTIVES: Tertiary prevention seeks to reduce chronic disease progression and illness-related dysfunction. Using the Aday-Andersen model, we evaluated the impact of predisposing, need, and enabling factors on tertiary prevention, hypothesizing that urban-rural geographic differences in delivery would be detected. METHODS: A population-based telephone survey was conducted evaluating six common chronic indicator conditions: arthritis (n = 488), hypertension (n = 414), cardiac disease (n = 185), diabetes mellitus (n = 125), peptic ulcer disease (n = 125), and chronic obstructive pulmonary disease (n = 103). Subjects were 787 (70% women) home-dwelling elderly (age > 65 years) who had one or more of the indicator conditions and who resided in Iowa's 12 most rural and 10 most urban counties. Tertiary prevention measures included counseling for and/or treatment with: influenza and pneumococcal vaccination, smoking cessation, dietary modifications, exercise, drug side effects, chronic disease rehabilitation, aspirin/estrogen for cardiac disease, and foot/eye care for diabetes. Tertiary prevention scores were calculated to compare preventive services across disease categories and to examine relations, in particular, with enabling factors. RESULTS: Education beyond high school, alcohol use, cigarette smoking, and medical specialist use were all significantly greater among urban residents, whereas home services use was greater among rural residents. Respondents with either health maintenance organization or fee-for-service supplemental coverage had higher tertiary prevention scores than respondents without supplemental coverage. After adjustment for the significant effects of the number of diseases, higher income, and place of residence, rural respondents having health maintenance organization supplemental coverage had higher (better) tertiary prevention scores than other respondents. CONCLUSIONS: In this community-based study of elderly, enrollment in an health maintenance organization plan, as opposed to a fee-for-service supplement to Medicare, increased tertiary prevention quality for rural but not for urban residents. This study emphasizes that additional research is needed to evaluate the importance of specific types of insurance coverage for preventive services among the elderly. 相似文献
992.
A Gibson K Baburaj DE Day I Verhamme JD Shore CB Peterson 《Canadian Metallurgical Quarterly》1997,272(8):5112-5121
Plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor of tissue-type plasminogen activator and urokinase, is known to convert readily to a latent form by insertion of the reactive center loop into a central beta-sheet. Interaction with vitronectin stabilizes PAI-1 and decreases the rate of conversion to the latent form, but conformational effects of vitronectin on the reactive center loop of PAI-1 have not been documented. Mutant forms of PAI-1 were designed with a cysteine substitution at either position P1' or P9 of the reactive center loop. Labeling of the unique cysteine with a sulfhydryl-reactive fluorophore provides a probe that is sensitive to vitronectin binding. Results indicate that the scissile P1-P1' bond of PAI-1 is more solvent exposed upon interaction with vitronectin, whereas the N-terminal portion of the reactive loop does not experience a significant change in its environment. These results were complemented by labeling vitronectin with an arginine-specific coumarin probe which compromises heparin binding but does not interfere with PAI-1 binding to the protein. Dissociation constants of approximately 100 nM are calculated for the vitronectin/PAI-1 interaction from titrations using both fluorescent probes. Furthermore, experiments in which PAI-1 failed to compete with heparin for binding to vitronectin argue for separate binding sites for the two ligands on vitronectin. 相似文献
993.
Yongping Chen Chengbin Zhang Mingheng Shi Jiafeng Wu G.P. Peterson 《International Journal of Heat and Mass Transfer》2009,52(3-4):636-643
A theoretical model of fluid flow and heat transfer in a heat pipe with axial “Ω”-shaped grooves has been conducted to study the maximum heat transport capability of these types of heat pipes. The influence of variations in the capillary radius, liquid–vapor interfacial shear stress and the contact angle are all considered and analyzed. The effect of vapor core and wick structure on the fluid flow characteristics and the effect of the heat load on the capillary radius at the evaporator end cap, as well as the effect of the wick structure on the heat transfer performance are all analyzed numerically and discussed. The axial distribution of the capillary radius, fluid pressure and mean velocity are obtained. In addition, the calculated maximum heat transport capability of the heat pipe at different working temperatures is compared with that obtained from a traditional capillary pressure balance model, in which the interfacial shear stress is neglected. The accuracy of the present model is verified by experimental data obtained in this paper. 相似文献
994.
Peterson Roger L.; Peterson Donald R.; Abrams Jules C.; Stricker George 《Canadian Metallurgical Quarterly》1997,28(4):373
Beginning with its historical context, the National Council of Schools and Programs of Professional Psychology's model for education and training in professional psychology is summarized in 5 areas: (a) broadened view of psychology with a flexible epistemology, multiple ways of knowing, and how practitioners doing practice remain local clinical scientists doing disciplined inquiry; (b) integrative pedagogy; (c) competency-based core curriculum integrating practical and scientific knowledge, skills, and attitudes; (d) elements of practice?including multiple roles, the self of the psychologist and reflective practice?practicum and internship training, and systematic evaluation; and (e) the social nature of professional psychology and its social responsibility, including ethnic and racial diversity and gender. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
995.
RE Kettner S Mahamud HC Leung N Sitkoff JC Houk BW Peterson AG Barto 《Canadian Metallurgical Quarterly》1997,77(4):2115-2130
A neural network model based on the anatomy and physiology of the cerebellum is presented that can generate both simple and complex predictive pursuit, while also responding in a feedback mode to visual perturbations from an ongoing trajectory. The model allows the prediction of complex movements by adding two features that are not present in other pursuit models: an array of inputs distributed over a range of physiologically justified delays, and a novel, biologically plausible learning rule that generated changes in synaptic strengths in response to retinal slip errors that arrive after long delays. To directly test the model, its output was compared with the behavior of monkeys tracking the same trajectories. There was a close correspondence between model and monkey performance. Complex target trajectories were created by summing two or three sinusoidal components of different frequencies along horizontal and/or vertical axes. Both the model and the monkeys were able to track these complex sum-of-sines trajectories with small phase delays that averaged 8 and 20 ms in magnitude, respectively. Both the model and the monkeys showed a consistent relationship between the high- and low-frequency components of pursuit: high-frequency components were tracked with small phase lags, whereas low-frequency components were tracked with phase leads. The model was also trained to track targets moving along a circular trajectory with infrequent right-angle perturbations that moved the target along a circle meridian. Before the perturbation, the model tracked the target with very small phase differences that averaged 5 ms. After the perturbation, the model overshot the target while continuing along the expected nonperturbed circular trajectory for 80 ms, before it moved toward the new perturbed trajectory. Monkeys showed similar behaviors with an average phase difference of 3 ms during circular pursuit, followed by a perturbation response after 90 ms. In both cases, the delays required to process visual information were much longer than delays associated with nonperturbed circular and sum-of-sines pursuit. This suggests that both the model and the eye make short-term predictions about future events to compensate for visual feedback delays in receiving information about the direction of a target moving along a changing trajectory. In addition, both the eye and the model can adjust to abrupt changes in target direction on the basis of visual feedback, but do so after significant processing delays. 相似文献
996.
A Thelin E Peterson JL Hutson AD McCarthy J Ericsson G Dallner 《Canadian Metallurgical Quarterly》1994,1215(3):245-249
The effects of squalestatin 1 on rat brain and liver homogenates and on Chinese hamster ovary tissue culture cells have been investigated. This compound effectively inhibits squalene biosynthesis in a highly selective manner. Cytoplasmic farnesyl pyrophosphate and geranylgeranyl pyrophosphate synthases are not affected, which is also the case for microsomal cis-prenyltransferase. In tissue culture cells, squalestatin 1 inhibits cholesterol biosynthesis completely, but does not alter dolichol synthesis or protein isoprenylation to a great extent. Incorporation of [3H]mevalonate into ubiquinone-9 and -10 increases 3-4-fold, probably as a result of increased synthesis of this lipid. Squalestatin 1 appears not only to be an effective inhibitor of cholesterol biosynthesis, but also to be more specific than other inhibitors used earlier in various in vitro and in vivo systems. 相似文献
997.
Noncondensable gases significantly modify the mechanism of condensation for cocurrent downward flow in vertical tubes. Two-dimensional experimental measurements presented here show similarity between gas concentration distributions and the temperature distributions encountered in laminar and turbulent heat transfer. Thus the analogy between heat and mass transfer, coupled with a reasonable condensate film model, can provide predictions of the local condensation rate. This work presents a simple 9-step iterative calculation procedure for calculating the local heat flux. The empirical model, based on a modified Dittus-Boelter formulation and utilizing an effective condensation thermal conductivity, converges with 2 to 10 iterations at each axial location. Experimental results from several investigators are compared with the predictions of the model, with good agreement. 相似文献
998.
Tetlock Philip E.; Armor David; Peterson Randall S. 《Canadian Metallurgical Quarterly》1994,66(1):115
Explores the relations among value conflict, cognitive style, and policy preferences in pre-Civil War America. Drawing on major historical works, prominent political figures were classified into 1 of 4 political positions: abolitionists, free-soil Republicans who would tolerate slavery in the South but prevent further spread, Buchanan Democrats who would permit slavery in new territories, and advocates of slavery. Results revealed (1) greatest integrative complexity among free-soil Republicans and Buchanan Democrats, with declines in complexity moving either leftward toward abolitionists or rightward toward slavery supporters; (2) integrative complexity was a positive function of endorsing values widely regarded as in conflict in that historical period (property rights, states' rights, and domestic peace vs the threat of "Southern slave power" to free labor and democracy). The results are consistent with the value pluralism model and raise warnings against the tendency to view integratively simple reasoning as both cognitively and morally inferior to complex reasoning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
999.
HB Peterson Z Xia JM Hughes LS Wilcox LR Tylor J Trussell 《Canadian Metallurgical Quarterly》1997,336(11):762-767
BACKGROUND: Tubal sterilization is an increasingly common method of contraception in the United States. Although pregnancy after sterilization is uncommon, it can occur and may be ectopic. We used data from the U.S. Collaborative Review of Sterilization to estimate the risk of ectopic pregnancy in women who had undergone the common types of tubal sterilization. METHODS: A total of 10,685 women undergoing tubal sterilization were followed in a multicenter, prospective cohort study. We intended to follow all the women for 5 years by means of annual telephone interviews; for women enrolled early in the study, we attempted an additional follow-up telephone interview 8 to 14 years after sterilization. To assess the risk of ectopic pregnancy in these women, we used cumulative life-table probabilities and proportional-hazards analysis. RESULTS: There were 47 ectopic pregnancies in the 10,685 women; the 10-year cumulative probability of ectopic pregnancy for all methods of tubal sterilization combined was 7.3 per 1000 procedures. The cumulative probability varied substantially according to the method of sterilization and the woman's age at the time of sterilization. Women sterilized by bipolar tubal coagulation before the age of 30 years had a probability of ectopic pregnancy that was 27 times as high as that among women of similar age who underwent postpartum partial salpingectomy (31.9 vs. 1.2 ectopic pregnancies per 1000 procedures). The annual rate of ectopic pregnancy for all methods combined in the 4th through 10th years after sterilization was no lower than that in the first 3 years. CONCLUSIONS: A history of tubal sterilization does not rule out the possibility of ectopic pregnancy, even many years after the procedure. 相似文献
1000.