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81.
Given integers m and n, we study the probability that structures of size n have all components of size at most m. The results
are given in term of a generalized Dickman function of n/m. 相似文献
82.
LONG TERM STORAGE STABILITY OF MIDDLE DISTILLATE FUELS FROM A CHEMICAL MECHANISTIC POINT OF VIEW. PART 2. 总被引:1,自引:0,他引:1
Bruce Beaver 《Petroleum Science and Technology》1992,10(1):1-37
The objective of this review is to (i) articulate the current level of understanding of the types of “reactive molecules” intimately involved in the long term oxidative storage instability of middle distillates, (11) review the types of chemical reaction mechanisms most likely involved in the “oxidative phase” of insoluble formation, (iii) review the postulated chemical mechanisms of stabilizer (additive) operation, and (iv) discuss future research areas that must be explored if a greater understanding and control of middle distillate instability is to be realized. 相似文献
83.
Two-hundred and one strains classified under the (Pasteurella) haemolytica-complex isolated from cattle, sheep, deer, pigs, hares and rabbits were investigated by ribotyping. Fifty-nine of these strains were selected for further studies using multilocus enzyme electrophoresis (MEE). A correlation between the clusters identified by ribotyping and MEE was demonstrated and the results furthermore indicated that a genetic basis exists for most clusters previously outlined by the use of quantitative evaluation of phenotypic data. The taxonomic relevance of ornithine decarboxylase and fermentation of L-arabinose, D-sorbitol and glucosides for taxonomic delineation within the (P.) haemolytica-complex was supported. A taxonomic importance was further indicated for ONPG, ONPX, ONPF, meso-inositol, D-xylose, maltose, dextrine and NPG in relation to some of the taxa. Within the porcine taxon 15, however, differences in ornithine decarboxylase did not correspond to genetic clusters. Six lineages were revealed by MEE. Lineage A contained electrophoretic types (ETs) representing biogroups 1, 3A-3H, 8A and 9, indicating a genetic relationship between these groups--an observation which was supported by ribotyping. Lineage B included biogroup 8D, 3 strains from biogroup 10 and a single strain from biogroup 1 and taxon 18/biovar 1. Lineage C contained strains allocated to biogroup 6 from ruminants and the porcine taxon 15. The similarity between these two groups was accentuated by ribotyping. Lineage D and the single isolate in lineage E contained strains allocated to biogroups 7, 10, 8B and 8C, in addition to single strains from biogroups 6 and 9. The same strains were found in the heterogenous ribotype cluster 17. Lineage F contained strains representing the leprine taxon 20 and the ruminant (P.) granulomatis. Ribotyping indicated that the ruminant biogroup 3J was affiliated with both taxon 20 and (P.) granulomatis. 相似文献
84.
Avants S. Kelly; Margolin Arthur; Kosten Thomas R.; Rounsaville Bruce J.; Schottenfeld Richard S. 《Canadian Metallurgical Quarterly》1998,66(6):924
In response to a need to match drug users to the most appropriate and cost-effective level of care, it was hypothesized that socially anxious methadone-maintained patients would attain greater benefit from coping skills training provided in the context of a low-intensity enhanced standard methadone maintenance intervention (E-STD) than in the context of a high-intensity, socially demanding day treatment program (DTP). Social anxiety was assessed in 307 methadone-maintained patients using the Social Anxiety and Distress Scale prior to randomization to either E-STD or DTP. The hypothesis was supported: Socially anxious patients were drug free longer during treatment, were more likely to be abstinent at treatment completion, and had greater reductions in HIV risk behaviors if assigned to the lower intensity intervention, which was provided at ? the cost of the DTP. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
85.
Interaction of human Arp2/3 complex and the Listeria monocytogenes ActA protein in actin filament nucleation 总被引:1,自引:0,他引:1
MD Welch J Rosenblatt J Skoble DA Portnoy TJ Mitchison 《Canadian Metallurgical Quarterly》1998,281(5373):105-108
Actin filament assembly at the cell surface of the pathogenic bacterium Listeria monocytogenes requires the bacterial ActA surface protein and the host cell Arp2/3 complex. Purified Arp2/3 complex accelerated the nucleation of actin polymerization in vitro, but pure ActA had no effect. However, when combined, the Arp2/3 complex and ActA synergistically stimulated the nucleation of actin filaments. This mechanism of activating the host Arp2/3 complex at the L. monocytogenes surface may be similar to the strategy used by cells to control Arp2/3 complex activity and hence the spatial and temporal distribution of actin polymerization. 相似文献
86.
DA Galuska M Serdula E Pamuk PZ Siegel T Byers 《Canadian Metallurgical Quarterly》1996,86(12):1729-1735
OBJECTIVES: Using data from the Behavioral Risk Factor Surveillance System, this study describes trends in the prevalence of overweight between 1987 and 1993. METHODS: Data were examined from 33 states participating in an ongoing telephone survey of health behaviors of adults (n = 387,704). Self-reported weights and heights were used to calculate sex-specific prevalence estimates of overweight for each year from 1987 to 1993. Time trends were evaluated with the use of linear regression. RESULTS: Between 1987 and 1993, the age-adjusted prevalence of overweight increased by 0.9% per year for both sexes (from 21.9% to 26.7% among men and from 20.6% to 25.4% among women). The increasing linear trend was observed in all subgroups of the population but was most notable for Black men (1.5% per year) and men living in the Northeast (1.4% per year). Secular changes in smoking and leisure-time physical activity did not entirely account for the increase in overweight. CONCLUSIONS: The prevalence of overweight among American adults increased by 5% between 1987 and 1993. Efforts are needed to explore the causes of this adverse trend and to find effective strategies to prevent obesity. 相似文献
87.
JM Larsen RL Rimoldi DA Capen RW Nelson S Nagelberg JC Thomas 《Canadian Metallurgical Quarterly》1996,9(2):117-120
Tribal warfare is a way of life in the highlands of Papua New Guinea. In earlier times direct confrontation with bushknives and axes, and shooting with bows and arrows were common. In recent years there have not been as many instances of direct confrontation with bushknives and axes, but the use of bows and arrows is on the rise. Since 1993, guns have been increasingly used, with devastating results. In 1993, 18 deaths were reported from tribal warfare in one area of the Southern Highlands Province, especially from gunshots, while in 1994, 24 deaths were reported from another area. A five-year review of tribal fight admissions to Mendi Hospital, from 1990 to 1994, showed an increase in the number and proportion of gunshot wounds; there were none in 1990-1992 but they constituted 18% of tribal fight injuries in 1993 and 33% in 1994. 相似文献
88.
IA Wilson RL Stanfield DA Jewell JB Ghiara DH Fremont EA Stura 《Canadian Metallurgical Quarterly》1994,3(2-3):155-162
The response exhibited by the immune system to viral and other foreign antigens consists of antibody-mediated and T cell-mediated immunity. Structural and molecular biological studies have shown that the antibody response is tailored to provide exquisite specificity by generating binding pockets that are complementary in shape as well as in charge to the antigen. On the other hand, the cellular response uses T-cell receptors (TCRs) and the major histocompatibility complex (MHC) antigens. Structural information on the TCRs is not yet available, but the crystal structures of several MHC class I molecules have shown how one MHC molecule can bind many different peptide sequences that share only the common anchor residue positions that determine allele specificity. MHC class I interactions with the peptide backbone at the N and C termini explain the high specificity of the binding groove for peptide ligands and suggest a universal mode of recognition for peptides to MHC class I molecules. Peptide-MHC class II interactions are less well understood, although recent structural work has shown important differences in the binding clefts of MHC class I and II that lead to longer peptides being bound to class II molecules. Detailed analysis at the molecular level has indicated that conformational changes in both antibodies and MHC molecules occur upon antigen binding.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
89.
MZ Ratajczak J Ratajczak DA Kregenow W Marlicz B Machalinski M Simon S Luger AM Gewirtz 《Canadian Metallurgical Quarterly》1997,2(2):5-11
Forty-one patients for whose direct care at least one machine was used and 33 registered nurses from the same five non-critical care units as the patients and from one related unit, participated in a semistructured tape-recorded interview to identify the core categories of the human-machine interface in clinical nursing practice and the relationships between them. Constant comparative analysis was used to organize and process the data. Patients perceived the machines as neutral because of their view of health care and because nurses were the interface between them and the machines. Nurses perceived the machines as either positive or negative, depending on their effect on the nurses' professional competence and the extent to which they worked directly with them. 相似文献
90.
Dobutamine stress echocardiography is a safe method for the evaluation of coronary artery disease, myocardial function, and viability. The potential for cardiac rupture exists. Although clinical and electrocardiographic criteria may be helpful in identifying those patients at risk for cardiac rupture, the criteria are neither sensitive nor specific enough to exclude patients or make recommendations regarding which patients should undergo dobutamine stress echocardiography in the post-infarction period. Physicians must be aware of the possibility and be prepared to treat cardiac rupture when performing dobutamine stress echocardiography. 相似文献