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排序方式: 共有511条查询结果,搜索用时 15 毫秒
1.
BD Shenstone A Mahmoud R Woodward D Elvins R Palmer EF Ring AK Bhalla 《Canadian Metallurgical Quarterly》1994,33(6):541-545
A prospective longitudinal study of patients with early RA was performed to examine the influence of disease duration, disease activity and physical activity on bone loss. Sixty-seven patients with non-steroid treated RA of less than 5 yr duration, including 16 patients with disease duration less than 6 months, had BMD measurements of the femoral neck and the lumbar spine over a 12-month period using dual energy X-ray absorptiometry. The BMD changes were compared with values from 72 control patients and were also correlated with serial measurements of disease activity (measured by the Stoke Index) and disability [measured by the Health Assessment Questionnaire (HAQ) score], at 3-monthly intervals over the 12-month period. No significant differences in BMD changes were found between RA patients and controls overall. Patients with disease duration of less than 6 months had significantly greater loss of BMD at the femoral neck (-3.9%, S.E.M. 1.5) than the remainder of the cohort (-0.2%, S.E.M. 0.7) (P = 0.02) and controls (-0.8%, S.E.M. 0.6). Lumbar spine BMD changes correlated with the initial Stoke Index (Rs-0.373, P = 0.01) but not mean Stoke Indices. There was no correlation of BMD changes with age or HAQ scores. These findings suggest that significant bone loss occurs within the first few months of disease in patients with RA. 相似文献
2.
BW Woodward JW Mabry MT See JK Bertrand LL Benyshek 《Canadian Metallurgical Quarterly》1993,71(8):2040-2046
An animal model and computer software were developed to conduct across-herd genetic evaluations using data from producers participating in the Sow Productivity Index program of the American Yorkshire Club. The final data set consisted of 61,596 litter records from 1986 to early 1990. The animal model included fixed contemporary group effects and random additive direct, service sire, permanent environmental, and residual effects. Additive genetic relationships among animals were included. A separate relationship matrix for service sires and their sires was also included. A data set similar to the Yorkshire field data was simulated to use in testing the animal model. The simulated data set consisted of 40 herds, each with 120 reproducing dams and either four or five sires. Six generations of simulated data were produced, resulting in 20,605 litter records. These records were then evaluated using the animal model for number of pigs born alive. Finally, correlations between the true breeding values from the simulation and the predicted breeding values were computed. The correlation between the 918 true and predicted sire breeding values was considerably lower for the animal model without a service sire effect than when it was included (.53 vs .74, respectively). However, the difference was cut in half (.66 vs .77) when only sires with greater than five daughter records were included. The high accuracy of the animal model with a random service sire effect indicates that the proposed model adequately accounts for the variation found in records for number of pigs born alive. 相似文献
3.
Woodward S.L. Koren U. Miller B.I. Young M.G. Newkirk M.A. Burrus C.A. 《Photonics Technology Letters, IEEE》1992,4(12):1330-1332
A distributed Bragg reflector (DBR) laser tuned by resistive heating is presented. It has a tuning range greater than 10 nm with only a 33% reduction in output power and a 10% increase in linewidth. Its behavior is easily modeled, agreeing well with simple theory 相似文献
4.
Woodward William R.; Benassi Victor A.; Knoth Russell 《Canadian Metallurgical Quarterly》1993,48(1):53
Commemorates G. M. Haslerud, who died suddenly on April 10, 1990. In his doctoral dissertation (1934) he addressed free and prescribed maze patterns in rats, pointing to a lifetime interest in creative transfer. In 1972 he completed his magnum opus, Transfer, Memory, and Creativity: After-Learning as Perceptual Process, which reflects continuing conversations with his mentor, Robert Yerkes. Haslerud is remembered as a co-founder of the New Hampshire Psychological Association. (0 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Splenomegaly is uncommon in myelodysplasia (MDS) and, although cytopenias may be severe, therapeutic splenectomy is rarely performed. We report the histologic, histochemical, and immunophenotypic findings of nine cases of surgical splenectomy and four postmortem spleens from MDS patients. Four histologic patterns were identified: one dominated by erythrophagocytosis, one characterized by red pulp plasmacytosis, one with extramedullary hematopoiesis as the only salient finding, and one with marked red pulp expansion caused by a monocytic proliferation. Wright-Giemsa and histochemical stains were performed on touch preparations in three cases and played a critical role in the precise subclassification of one MDS patient's hematologic disorder, which ultimately proved to be chronic myelomonocytic leukemia. Splenectomy led to sustained improvement of cytopenias in three cases, but did not eliminate transfusion dependence for the remaining patients. Three splenectomy cases exhibited clustered Leder-negative mononuclear elements: two of these patients experienced disease progression to refractory anemia with excess blasts in transformation or acute myelogenous leukemia during post-splenectomy follow-up, whereas none of the three splenectomy patients without clustered mononuclear elements did. We conclude that splenomegaly in MDS usually reflects the sequelae of dyspoiesis rather than evidence of a proliferative phase, that clustering of Leder-negative large cells may correlate with either a substantial monocytic component or, possibly, increased risk of disease progression, and that the spleen can provide diagnostic as well as prognostic information in MDS patients with splenomegaly. 相似文献
6.
ON GENERALIZED FRACTIONAL PROCESSES 总被引:3,自引:0,他引:3
Abstract. A class of stationary long-memory processes is proposed which is an extension of the fractional autoregressive moving-average (FARMA) model. The FARMA model is limited by the fact that it does not allow data with persistent cyclic (or seasonal) behavior to be considered. Our extension, which includes the FARMA model as a special case, makes use of the properties of the generating function of the Gegenbauer polynomials, and we refer to these models as Gegenbauer autoregressive moving-average (GARMA) models. While the FARMA model has a peak in the spectrum at f = 0, the GARMA process can model long-term periodic behavior for any frequency 0 f 0.5. Properties of the GARMA process are examined and techniques for generation of realizations, model identification and parameter estimation are proposed. The use of the GARMA model is illustrated through simulated examples as well as with classical sunspot data. 相似文献
7.
Hyunjun Kim Brahim Akdim James Park Woo-Yong Jang Randall S. Hay Augustine M. Urbas Christopher Woodward 《Journal of the American Ceramic Society》2021,104(11):5659-5670
High-throughput computation, based on density functional theory (HT-DFT), is used to predict the bounds for optical transparency, from the ultraviolet to the infrared, for materials in the pyrochlore family. The HT-DFT approach adopted here uses an initial screening from Materials-Project database, with millions of calculated properties. Band gaps and phonon spectra were calculated from selected pyrochlore crystal structures taken from the Materials Project database. Short and long wavelength bounds for optical transparency were calculated for chemistries with stable, cubic structures. The calculations predict that La2Ce2O7 has one of the broadest range of transparency for the pyrochlore family. Based on these calculations, dense polycrystalline samples of La2Ce2O7 were produced by sintering and hot-isostatic pressing. Transparency was characterized by methods that did not require large samples with high optical quality, obtaining 7.15 and 7.5 µm at 95% and 90% normalized transmittance, respectively. Bandgap calculations suggest a lower bound of UV transparency cut-off of 0.3 µm. The infrared wavelength cut-off is higher than that reported for other pyrochlores, and higher than for yttria, zirconia, or other common infrared transparent ceramics. We discuss our prediction and characterization methods as well as the suitability of pyrochlores for mid- and far-infrared optical applications. 相似文献
8.
The I-40 bridges over the Rio Grande in Albuquerque, New Mexico were due to be razed in the fall of 1993 due to geometry and traffic safety considerations, thus providing a unique opportunity for testing them. These medium span steel bridges represent a common design in the US and are classified by AASHTO as non-redundant ‘fracture critical’ two girder steel bridges (fracture critical classification means that failure of a primary member would probably cause collapse of the bridge). The subject bridge, built in 1963, is a 1275 foot (600m) bridge, and consists of three medium span continuous units with spans of 131′-163'−131′ each. The bridge was field tested to determine the impact of a near full depth girder fracture on the redistribution of loads, the load capacity, and the potential for collapse. Four levels of damage were introduced in the middle span of the north plate girder by making various cuts in the web and the flange of the girder. The final cut resulted in a six foot deep crack in the 10ft deep girder, extending from the bottom flange to the floor beam to girder connection. Data was taken under dead load and under a static live load consisting of an 82 000 lb truck. The after fracture response and the load redistribution in the fractured bridge were evaluated. The contribution of the different members to the redundancy of the structure was assessed. 相似文献
9.
10.
Rasha Osman Irfan Awan Michael E. Woodward 《Simulation Modelling Practice and Theory》2011,19(1):251-270
Databases form the common component of many software systems. However, performance models specifically targeted at the database design have not been extensively studied. In this paper, we propose QuePED – a queueing network performance evaluation model for database designs. QuePED provides for the performance modelling of database design constructs, including active database rules; thus, deviating from current methods that consider database designs as processing demands on the hardware architecture. We present a formal specification of QuePED and describe its application to database designs. Experimental evaluation has shown the ability of QuePED to capture the steady state performance of an implementation of the TPC-C benchmark. 相似文献