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991.
992.
993.
Alan E. Johnson WŁOdztmierz Jarzęba Gilbert C. Walker Paul F. Barbara 《Israel journal of chemistry》1993,33(2):199-206
The class of compounds containing a carbonyl group substituted at the 9 position of anthracene have been studied as new model systems for torsional isomerization in solution. Franck-Condon excitation yields an excited-state distribution near the barrier for isomerization in S1. Using time-resolved fluorescence spectroscopy, we have determined that the relaxation from the barrier region is subpicosecond for three different compounds in all solvents studied. In fact, the relaxation seems to be almost independent of solvent at room temperature, indicating that most of the local friction felt by the twisting carbonyl is internal friction rather than solvent friction. Apparently the small carbonyl is effectively shielded from the solvent by the anthracene ring so the solvent friction is not strong. In contrast to the weak solvent coupling, previously reported gas-phase spectra indicate that the torsion may be strongly coupled to the other vibrational modes of the molecule. Energy flow out of the torsion into these other vibrational modes appears to occur on the subpicosecond time scale. 相似文献
994.
We examined the existence of temporal dimensions of organization culture (e.g., norms of time in organizations) and developed an instrument to measure those dimensions to facilitate cross-organizational and intraorganizational comparisons. A questionnaire designed to measure 15 hypothesized temporal dimensions was completed by 529 respondents from 51 work groups in 23 organizations. The sample was selected to meet certain criteria concerning organization type, organization size, and work group type. A principal components analysis extracted 13 usable scales: Time Boundaries Between Work and Nonwork, Sequencing of Tasks, Punctuality, Allocation, Awareness, Synchronization and Coordination, Variety Versus Routine, Intraorganizational Time Boundaries, Future Orientation, Schedules and Deadlines, Work Pace, Autonomy of Time Use, and Quality Versus Speed. Two hypothesized scales (Buffer in Planning and Buffer in Workday) did not emerge. Applications of the Time Dimensions Scales are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
995.
The bacterial endospores of C. sporogenes ATCC 3584 are quite small (approximately 0.7–1.0 μm in length) and are difficult to examine during the attachment and germination process by conventional light microscopy methods. Although transmission electron microscopy provides high magnification and resolution, it has not been possible to date to visualize the attachment process and surface changes of intact clostridial endospores. With the advent of higher resolution conventional scanning electron microscopes (SEM), it is now possible to study these small spores attached to their nutrient substrate in their intact state and readily obtain detailed morphologic information about the attachment, germination, and outgrowth process. Spores were examined in their dormant, dehydrated state and allowed to germinate. Samples were prepared for light, transmission, and SEM under anaerobic conditions for morphologic and histochemical examination. SEM revealed that the spores developed a distinct polarity at the beginning of the germination process and that the exosporial membrane at this time produced projections that attached the spore to a substrate. These projections were altered by calcium chelation with EDTA and the presence of barium. Following colchicine and cytochalasin B treatment, the exosporial membrane projections were morphologically altered and the germination sequence was modified. Histochemical examination of the spores suggested that calcium was predominantly located in the protoplast and spore coat. 相似文献
996.
Jane E. Lancaster Barbara J. McCallion Martin L. Shaw 《Journal of the science of food and agriculture》1984,35(4):415-420
Flavour precursors, the S-alk(en)yl-L -cysteine sulphoxides, change considerably in both concentration and total amount during the growth of onions. For the brown onion cv. Pukekohe Long Keeper (PLK) and for the white onion cv. Dehyso, (±)-S-1-propyl-L -cysteine sulphoxide (±PCSO) is the predominant flavour precursor, with (±)-trans-S-1-propenyl-L -cysteine sulphoxide (±PECSO) and (±)-S-1-methyl-L -cysteine sulphoxide (±MCSO) in a minor role. For PLK the greatest concentration of all three precursors is just prior to bulbing (3.6±1.1 mg g?1 fresh weight); for Dehyso the greatest concentration is at bulbing (4.6±0.6 mg g?1 fresh weight); Both varieties show a mid-season reduction in flavour precursor concentration (of about 45%), followed by a small but significant increase in ±PCSO concentration during the end of season leaf die-down. The total amount of the three flavour precursors per bulb in both varieties shows a maximum in late January (360±107 mg for PLK, 602±144 mg for Dehyso). In the subsequent months there is a dramatic reduction in the total amount of ±PECSO and ±MCSO, and a slight reduction in ±PCSO. Both varieties show an increase in the amount of ±PCSO at leaf die-down. The relative proportions of these flavour precursors change with bulb age and cultivar. These results suggest that white onions used for drying and processing could be harvested from bulbing onwards. Furthermore, when onion cultivars and onion plant selections are assessed for flavour, care needs to be given to the stage of maturity of the onion. 相似文献
997.
Abrams Dominic; Viki G. Tendayi; Masser Barbara; Bohner Gerd 《Canadian Metallurgical Quarterly》2003,84(1):111
In Studies 1 and 2, after reading an acquaintance-rape but not a stranger-rape scenario, higher benevolent sexist but not hostile sexist participants blamed the victim significantly more. In Study 2, higher hostile sexist but not benevolent sexist male participants showed significantly greater proclivity to commit acquaintance (but not stranger) rape. Studies 3 and 4 supported the hypothesis that the effects of benevolent sexism and hostile sexism are mediated by different perceptions of the victim, as behaving inappropriately and as really wanting sex with the rapist. These findings show that benevolent sexism and hostile sexism underpin different assumptions about women that generate sexist reactions toward rape victims. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
998.
The influence of testosterone and estrogen on memory was investigated in 33 healthy young men. Tests of visual memory, visuospatial ability, verbal memory, and attention were administered, and circulating levels of estradiol and free testosterone were measured. Participants with high levels of estradiol performed better on 2 measures of visual memory than did those with normal but lower levels. There were no differences between individuals with high and low levels of testosterone on any cognitive measure. These results support the contention that estradiol influences memory in young men. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
999.
Holloway Elizabeth L.; Freund Richard D.; Gardner Sharon L.; Nelson Mary Lee; Walker Barbara R. 《Canadian Metallurgical Quarterly》1989,36(1):88
Power and involvement are two fundamental dimensions of primary relationships. We studied the relevance of these two dimensions in the supervisory relationship. A multiple-case-study approach was used to describe systematically the discourse of the five supervision interviews of the Goodyear (1982) series, Psychotherapy Supervision by Major Theorists; we compared these results with previous findings that have reported impressional characteristics of the interviews. The content-analysis scheme used to describe the discourse was developed by Penman (1980) and includes both manifest and latent levels of communication organized on the two dimensions of power and involvement. The sequences of verbal messages in each of the interviews were analyzed by using unidirectional and dominance sequential tests. The results indicate that although there was a primary pattern of teacher–learner interaction in all interviews, each interview exhibited a unique style with regard to the sequences of messages between supervisor and supervisee and the characteristics of power and involvement as defined by the Penman scheme. We discuss the characteristics of the interviews, as described by the results of the content and sequential analyses, in relation to the theoretical orientation of each supervisor. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
1000.
Judges were asked to fairly assign priority ratings to hypothetical candidates applying to medical school, given information about their Medical College Aptitude Test scores, grade-point averages, and group memberships (majority or minority). The affirmative action goal and the qualifications of minorities relative to majorities in the applicant pool were also manipulated. When there is no specified affirmative action goal nor differences between groups in the applicant pool, minorities and majorities are treated similarly. When either group differences in the applicant pool occur or affirmative action goals are introduced, decision makers assign higher priority ratings to minorities than to equally qualified majority applicants. When both factors are operating, minorities receive an even bigger boost. Results are consistent with the hypothesis that decision makers evaluate minority and majority candidates in the same way; differences between groups occur in the response function. Equally qualified majority and minority candidates are assigned to different categories, depending on the size of the affirmative action goal and the extent to which the two groups differ in the applicant pool. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献