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21.
Given the prevalence of computers in education today, it is critical to understand teachers’ perspectives regarding computer integration in their classrooms. The current study surveyed a random sample of a heterogeneous group of 185 elementary and 204 secondary teachers in order to provide a comprehensive summary of teacher characteristics and variables that best discriminate between teachers who integrate computers and those who do not. Discriminant Function Analysis indicated seven variables for elementary teachers and six for secondary teachers (accounting for 74% and 68% of the variance, respectively) that discriminated between high and low integrators. Variables included positive teaching experiences with computers; teacher’s comfort with computers; beliefs supporting the use of computers as an instructional tool; training; motivation; support; and teaching efficacy. Implications for support of computer integration in the classroom are discussed.  相似文献   
22.
A polynomial displacement basis for the three-node plate bending element (Zienkiewicz-triangle) is developed from a relaxed C1-continuity requirement called the interpolation test. The test provides a general convergence criterion for non-conforming shape functions and a practical guideline to select a proper displacement basis. The resulting simple displacement type element passes the patch test. Several reduced numerical integration schemes are discussed and numerical testing provides a comparison with the standard element formulated by Zienkiewicz.  相似文献   
23.
The color stability of fresh ground veal from four different muscles (biceps femoris, longissimus dorsi, psoas major and supraspinatus) was characterized, and the effects of lipid oxidation, iron and zinc on this degradative process were investigated. Samples were minced and prepared in a manner consistent with retail production and analyzed for pH, myoglobin concentration, total and nonheme iron, and zinc. Pigment and lipid oxidation were measured on days 0, 3 and 6 of 4°C storage. B. femoris demonstrated the greatest extent of lipid oxidation, and was more color-labile than p. major or supraspinatus (P < 0·05), but no different from l. dorsi (P > 0·05). Total iron and myoglobin concentrations were lowest for l. dorsi (P<0·05). Zinc concentration in the four muscles followed the order supraspinatus ? b. femoris ? l. dorsi ? p. major (P < 0·05). Data analysis revealed that initial metmyoglobin formation (days 0 to 3) was significantly correlated with total iron (r = 0·69) or nonheme iron (r = 0·68) in b. femoris, but not any of the other muscles. Correlations between lipid and pigment oxidation in each of the four muscles were performed and the data support a strong relationship between these degradative processes in ground veal.  相似文献   
24.
In order for many large-scale bulk applications of high-temperature superconducting materials to be realized, the cost/performance of the superconductors needs to be optimized. From a performance standpoint, a long, flexible, single-crystal-like wire is required; from a cost-and-fabrication standpoint, an industrially scalable, low-cost process is required. Both of these critical requirements are met by rolling-assisted biaxially textured substrates, a conductor-fabrication technique that employs simple, scalable, thermomechanical processing techniques to obtain a near-single-crystal-like, flexible metal substrate in arbitrary lengths on which epitaxial oxide buffer layers and superconductors are then deposited. For more information, contact A. Goyal, Oak Ridge National Laboratory, P.O. Box 2008, MS 6116, Oak Ridge, Tennessee 37831; (423) 574-1587; fax (423) 574-7659.  相似文献   
25.
PURPOSE: To investigate the development of fluoroquinolone resistance among Neisseria gonorrhoeae isolates in Japan and the frequency and patterns of mutations involving the GyrA and ParC proteins, which confer quinolone resistance to the bacteria, in isolates. MATERIALS AND METHODS: Antimicrobial susceptibilities of 145 gonococcal isolates, including 79 isolated from February 1992 through February 1993 and 66 isolated from February 1995 through February 1996, to six fluoroquinolones and several other antibiotics were compared with those of 27 isolates obtained from 1981 through 1984. To identify mutations in gyrA and parC genes of the isolates, the quinolone resistance-determining regions of the gyrA and parC genes were PCR-amplified and the PCR products were directly sequenced. RESULTS: The minimum inhibitory concentration for 90% of strains (MIC90) values of norfloxacin for the isolates from 1992 to 93 (4 microg./ml.) and 1995 to 96 (8 microg./ml.) were 16- and 32-fold, respectively, higher than those for isolates from 1981 to 84 (0.25 microg./ml.). The MIC90 values of ciprofloxacin for isolates from 1992 to 93 (0.5 microg./ml.) and 1995 to 96 (1 microg./ml.) showed increase of 8- and 16-fold, respectively, in comparison with those from 1981 to 84 (0.063 microg./ml.). The isolates from 1992 to 93 and 1995 to 96 were also less susceptible to newer fluoroquinolones including levofloxacin, sparfloxacin, DU-6859a and AM-1155, as compared with those from 1981 to 84. In 46 (67.6%) and 16 (23.5%) of the 68 gonococcal strains sequenced, GyrA and ParC mutations were identified, respectively. No ParC substitutions were identified in any isolates without co-existence of the GyrA mutation. A Ser-91 to Phe mutation, which was detected in 30 (65.2%) of the 46 isolates with GyrA mutations, was the most common GyrA mutation. Mutants with the single Ser-91 to Phe substitution in GyrA were 12-fold and at least 13-fold, respectively, less susceptible to norfloxacin and ciprofloxacin than the wild type. CONCLUSIONS: The results obtained in this study suggest that a high prevalence of gonococcal isolates with the Ser-91 to Phe mutation in GyrA has reduced the susceptibility of this organism to fluoroquinolones in Japan.  相似文献   
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Zusammenfassung Die hochschmelzenden Metalle der VA-Gruppe und der VIA-Gruppe k?nnen bei h?heren Temperaturen Gase interstitiell in L?sung aufnehmen. Dadurch ergeben sich entscheidende Ver?nderungen vieler mechanischer und physikalischer Eigenschaften der Metalle. Es werden die Vorg?nge bei der Gasaufnahme und der Gasabgabe besprochen sowie insbesondere Daten über Eigenschafts?nderungen der Metalle durch gel?ste Gase, Daten über die Kinetik der Gasaufnahme und der Gasabgabe sowie Beziehungen zum Berechnen thermodynamischer Gleichgewichte und station?rer Zust?nde angegeben. Dabei finden die Metalle V, Nb, Ta, Mo, W und die Gase N2, O2, H2, H2O, CO sowie CH4 Berücksichtigung. An Hand einiger Anwendungs-beispiele wird auf die Bedeutung von Gas-Metall-Reaktionen in der Praxis hingewiesen.  相似文献   
29.
Möglichkeiten zur Verbesserung der Entphosphorung bei den Sauerstoffaufblas-Verfahren. Versuche zum Einblasen von Kalkstaub mit Sauerstoff in das Bad. Schnelles Erreichen des Phosphorgleichgewichts beim Einblasen von Kalkstaub.  相似文献   
30.
Juvenile aponeurotic fibroma is an uncommon benign tumor which occurs mostly in the hands and wrists of young children. It has a tendency to recur, especially in younger individuals, and this, combined with a rather cellular microscopic appearance, has led to mistaken diagnoses of malignancy. No instances of metastasis have been reported. Conservative therapy, consisting of excisional biopsy without sacrifice of vital structures, is indicated.  相似文献   
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