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排序方式: 共有236条查询结果,搜索用时 78 毫秒
41.
Les Alberthal 《Engineering Management Journal; EMJ》2013,25(2):5-7
ABSTRACTThis article discusses adopting quality function deployment to develop an effective and efficient process measurement program. The project was conducted at the Naval Undersea Warfare Center (NUWC) in Norfolk, Virginia, over a 5-month period. The objective was to develop a measurement program for a software maintenance by identifying the critical metrics for the entire process. As a result, 23 quality metrics were developed for NUWC's process measurement program. Also discussed are the benefits achieved during the quality function deployment process. 相似文献
42.
The conventional determination of model parameter errors in least-squares regression of experimental cyclic voltammetric data assumes validity of local approximations (e.g., linearization) in the parameter space and normal distributions of the data and parameter errors. Such assumptions may not always be satisfied in practice. Bootstrap resampling techniques present a more universally applicable approach to error estimation, which until now has not been used in cyclic voltammetric studies, owing to the high costs of the required voltammogram simulations. We demonstrate that the burden of computing voltammograms can be significantly reduced by the use of high-dimensional model representation (HDMR) solution mapping techniques, thereby making it feasible to apply the bootstrap data analysis in cyclic voltammetry. We perform computational experiments with bootstrap resampling, enhanced by HDMR maps, for a typical cyclic voltammetric model (i.e., the Eqrev Cirr Eqrev reaction mechanism at a planar macroelectrode under semi-infinite, pure diffusion transport conditions). The experiments reveal that the bootstrap distributions of the estimated parameters provide a satisfactory quantification of the parameter errors and can also be used for detecting statistical correlations of the parameters. 相似文献
43.
Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method1 was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity. 相似文献
44.
Reviews the book, The challenge of the borderline patient: Competency in diagnosis and treatment by Jerome Kroll (see record 1988-97021-000). In this new volume on borderline psychopathology, Jerome Kroll has some axes to grind-of the kind found in DSM-III, that is. He offers a refreshing perspective on this popularized topic and casts a healthy skepticism on the current trends and trendiness reflected in the literature. Unique in its back-to-basics, common-sensical approach to diagnosis and treatment, the book, in its essence, aims at demystifying and debunking the aura that surrounds this field. Kroll's volume spans the three predominant areas of inquiry that constitute most of the published works on borderline personality disorders, namely: 1) empirically rooted efforts to establish its construct validity as a diagnostic entity, 2) psychotherapeutic strategies that are primarily enmeshed in larger, unresolved theoretical controversies between the object relations versus self psychology factions within contemporary psychoanalytic thinking, and 3) the search for the magical psychopharmacological bullet that will eradicate borderline symptomotology. For both novice and experienced clinician, this book serves as a useful counterpoint to the current directions in empirical and theoretical work on borderline pathology, a reminder of the potential dangers of getting caught up in methodological precision or overelaborated theory or high-technology psychopharmacology and, as a consequence, of losing sight of the individual, whole patient. It is supportive therapy of the best kind for those of us who face the challenge of treating the borderline patient. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
45.
F. Les. Erickson Ernest M. Hannig Alyssa Krasinskas Richard A. Kahn 《Yeast (Chichester, England)》1993,9(8):923-927
A gene encoding a homologue of the ADP-ribosylation factor (ARF) family of small GTP binding proteins was cloned from a Schizosaccharomyces pombe cDNA library by a functional screen of suppressors of sensitivity to 3-aminotriazole in a gcn3 null strain of Saccharomyces cerevisiae. Two independent isolates each contained the full coding region of the ARF1 gene. The encoded SpARF1 protein has a predicted molecular weight of 20 618 and is 88% and 79% identical to human and S. cerevisiae ARF1 proteins, respectively. As independent isolates were obtained, this effect of the SpARF1 appears to be a real phenomenon, but cannot currently be easily understood within the context of the evidence for a role(s) for ARF proteins in the protein secretory pathway. 相似文献
46.
Les Greenberg Christine A. Johnson James C. Trager J. Steven McElfresh Joshua Rodstein Jocelyn G. Millar 《Journal of chemical ecology》2018,44(6):547-555
Species of the ant genus Polyergus are social parasites that steal brood from colonies of their hosts in the closely related genus Formica. Upon emergence as adults in a mixed population, host Formica workers carry out all the normal worker functions within the Polyergus colony, including foraging, feeding, grooming, and rearing brood of the parasitic Polyergus ants. Some unmated Polyergus gynes (queens) run in the raiding columns of their colonies and attract males by releasing a pheromone from their mandibular glands. There are two Polyergus species groups in North America: an eastern P. lucidus group and a western P. breviceps group. One species of each of these groups, P. lucidus Mayr and P. mexicanus Emery, are sympatric in Missouri. In this study, we characterized the sex pheromones of virgin queens of two species of the P. lucidus group (P. lucidus sensu stricto and P. sanwaldi) and one species of the P. breviceps group (P. mexicanus), and compared these with the previously identified sex pheromone of P. topoffi of the P. breviceps group. We then used sex pheromone blends reconstructed from synthesized components of the two groups to test their efficacy at reproductively isolating these species. We found that methyl 6-methylsalicylate is conserved as the major component of the pheromone blends for both Polyergus species groups; however, methyl (R)-3-ethyl-4-methylpentanoate is the species-specific minor component produced by P. lucidus group queens, and (R)-3-ethyl-4-methylpentan-1-ol is the crucial minor component for P. breviceps group queens. The optimal ratio of the major and minor components for P. lucidus group queens was about 100:1 salicylate to ester. In concurrent field trials in Missouri, males of P. lucidus sensu stricto and P. mexicanus (a member of the P. breviceps group) were attracted almost exclusively to their particular blends of sex pheromone components. To our knowledge, this is the first example of a possible sex-pheromone-based reproductive isolating mechanism in ants. 相似文献
47.
Robert H. White Mark A. Dietenberger Hao Tran Ondrej Grexa Les Richardson Kuma Sumathipala Marc Janssens 《火与材料》1999,23(3):139-146
As part of international efforts to evaluate alternative reaction‐to‐fire tests, several series of room/corner tests have been conducted. Materials tested were mostly different wood products but included gypsum board and a few foam plastics. This is a review of the overall results of related studies in which the different test protocols for the standard room/corner test were used. Differences in the test protocols involved two options for the ignition burner scenario and whether or not the ceiling was also lined with the test materials. The test materials were placed on three walls of the room in all the tests. The two burner scenarios were (1) 40 kW for 300 s followed by 160 kW for 300 s and (2) 100 kW for 600 s and 300 kW for 600 s. The 40 and 160 kW burner scenario without the ceiling lined did not provide a severe enough test for flashover to occur with fire‐retardant‐treated materials. Use of the 100 and 300 kW burner scenario without lining the ceiling provided the ability to differentiate between wood products with ASTM E 84 flame spread indexes of 70 to 125 and those with higher flame spread indexes. Lining the ceiling with test material creates a more severe test. 相似文献
48.
BACKGROUND: Apoptosis that has been reported in human atherosclerosis may contribute to the remodeling of atherosclerotic plaques. The identification of specific markers for apoptosis in these plaques would permit the development of specific therapeutic strategies to limit their progression. Cysteine protease CPP-32 is essential for apoptotic death in mammalian cells and appears to be an attractive candidate. METHODS AND RESULTS: We studied 12 atherosclerotic plaques from 12 patients who underwent carotid endarterectomy. Apoptosis was analyzed by in situ end labeling of fragmented DNA (TUNEL method) and corroborated by the presence of DNA fragmentation in agarose gel electrophoresis. CPP-32 was detected with the use of a specific monoclonal antibody, and its expression was compared with that of interleukin-1beta-converting enzyme (ICE). We showed that CPP-32 was highly expressed in 10 of 12 atherosclerotic plaques and that it colocalized with apoptotic cells. Expression of ICE generally paralleled that of CPP-32, but ICE was also detected in plaques negative for CPP-32 and showing no apoptosis. CONCLUSIONS: CPP-32 is highly expressed within human atherosclerotic plaques and is closely related to apoptosis. This finding suggests that CPP-32 may be the ICE-like enzyme responsible for apoptosis in human atherosclerosis and opens new perspectives for the development of therapeutic strategies to alter the progression of this disease. 相似文献
49.
The legal implications of professionals relying on expert systems have been extensively studied by analysts who have considered the ‘macro’ issues such as whether products liability can be invited for loss resulting from errors in expert systems, and apportionment of liability. These macro‐analyses do not distinguish programming errors from what we call ‘errors of reasoning’. The latter errors may be considered to be advertent on the part of developers and/or user‐professionals; may potentially be directly compared with the reasoning ascribable to a reasonably competent professional; and cannot be removed merely by better quality assurance in the sense prevalent in software engineering. In this paper we consider the mechanisms by which a court may examine errors of reasoning in expert systems used to assist professionals working in certain areas of financial services ('the financial‐legal domain'). Our analysis of the ‘micro’ issues of liability shows that the advertent nature of errors of reasoning makes it difficult to argue that using the best possible quality assurance methods during development is sufficient to make the reliance on an expert system reasonable. However, certain valuable defences that are available to professionals acting unaided can be made out even when expert systems are employed as part of the reasoning process, though these defences will be disabled if certain conceptual structures of the knowledge of professionals are not distinctively maintained in the knowledge base. As such, opacity of a knowledge base assists, rather than hinders, a plaintiff in establishing professional negligence. The results of an analysis of the micro‐issues of liability have been applied by us in the design of a system for financial/tax planning. A case‐based reasoning approach is employed, deductive rules being employed strictly in a subsidiary role. Consequently, the primary justification for a decision is a ‘case’ ‐ an instance of problem‐solving by a professional ‐ that is likely to be accepted by the court as being representative of the actions of reasonably competent professionals. 相似文献
50.
Paired metacarpi obtained at necropsy from 100 horses ranging in age from term fetus to 35 years were examined to estimate the prevalence and sites of metacarpal fusion. Metacarpal fusion was seen in 192 of 200 metacarpi, and 78% of all horses 2 years or older had 2 or more fusions. Fusion of the second metacarpal bone to the third metacarpal bone was significantly (P < 0.001) more common than was fusion of the fourth to the third metacarpal bone. Fusions appeared for the most part in pairs and were bilaterally symmetric. Rooney-Prickett type-A carpometacarpal joint configurations (in which there is no measurable articulation between the third carpal and second metacarpal bones) were rare in this population, and Rooney-Prickett type-B configurations (in which there is a measurable articulation between the third carpal and second metacarpal bones) were observed in 98.5% of metacarpi. Medial metacarpal fusion was positively correlated with age, occupation, and proportion of the proximal projection of the carpometacarpal distal joint surface that was taken by the second metacarpal bone. Lateral metacarpal fusion was positively correlated with age and the proportion of the proximal projection of the carpometacarpal distal joint surface taken by the fourth metacarpal bone. Horses in performance careers (racing, race training, or show ring occupations) had an earlier development of the first 2 fusions than did horses in other or unknown occupations; development of the third and fourth fusions were not significantly different between occupation groups. The rate of metacarpal fusion per horse-year appeared to be at least 10 times higher than a clinically evident rate. A variety of gross morphologic features was observed in the fusions from this sample, some of which were small, subtle, and possibly difficult to detect in vivo. It is hypothesized that many instances of metacarpal fusion may be a result of functional adaptation of the metacarpus to increased or changed loading conditions, rather than a response to isolated traumatic events. 相似文献