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排序方式: 共有3262条查询结果,搜索用时 15 毫秒
961.
962.
Vincent Baudoui Patricia Klotz Jean-Baptiste Hiriart-Urruty Sophie Jan Franck Morel 《Structural and Multidisciplinary Optimization》2012,46(5):711-726
In this paper, we develop an easy-to-implement approximate method to take uncertainties into account during a multidisciplinary optimization. Multidisciplinary robust design usually involves setting up a full uncertainty propagation within the system, requiring major modifications in every discipline and on the shared variables. Uncertainty propagation is an expensive process, but robust solutions can be obtained more easily when the disciplines affected by uncertainties have a significant effect on the objectives of the problem. A heuristic method based on local uncertainty processing (LOUP) is presented here, allowing approximate solving of specific robust optimization problems with minor changes in the initial multidisciplinary system. Uncertainty is processed within the disciplines that it impacts directly, without propagation to the other disciplines. A criterion to verify a posteriori the applicability of the method to a given multidisciplinary system is provided. The LOUP method is applied to an aircraft preliminary design industrial test case, in which it allowed to obtain robust designs whose performance is more stable than the one of deterministic solutions, relatively to uncertain parameter variations. 相似文献
963.
Isabel Lastres-Becker Gracia Porras Marina Arribas-Blzquez Ins Maestro Daniel Borrego-Hernndez Patricia Boya Sebastin Cerdn Alberto García-Redondo Ana Martínez ngeles Martin-Requero 《International journal of molecular sciences》2021,22(6)
Amyotrophic lateral sclerosis (ALS) is a fatal neurological condition where motor neurons (MNs) degenerate. Most of the ALS cases are sporadic (sALS), whereas 10% are hereditarily transmitted (fALS), among which mutations are found in the gene that codes for the enzyme superoxide dismutase 1 (SOD1). A central question in ALS field is whether causative mutations display selective alterations not found in sALS patients, or they converge on shared molecular pathways. To identify specific and common mechanisms for designing appropriate therapeutic interventions, we focused on the SOD1-mutated (SOD1-ALS) versus sALS patients. Since ALS pathology involves different cell types other than MNs, we generated lymphoblastoid cell lines (LCLs) from sALS and SOD1-ALS patients and healthy donors and investigated whether they show changes in oxidative stress, mitochondrial dysfunction, metabolic disturbances, the antioxidant NRF2 pathway, inflammatory profile, and autophagic flux. Both oxidative phosphorylation and glycolysis appear to be upregulated in lymphoblasts from sALS and SOD1-ALS. Our results indicate significant differences in NRF2/ARE pathway between sALS and SOD1-ALS lymphoblasts. Furthermore, levels of inflammatory cytokines and autophagic flux discriminate between sALS and SOD1-ALS lymphoblasts. Overall, different molecular mechanisms are involved in sALS and SOD1-ALS patients and thus, personalized medicine should be developed for each case. 相似文献
964.
How does work setting relate to burnout among professional psychologists? Five hundred and seventy-one doctoral psychologists responded to a survey about professional activities, work environment, and burnout. Solo and group independent practitioners reported a greater sense of personal accomplishment than agency respondents. However, women experienced higher levels of emotional exhaustion in agency settings than in either solo or group independent practice, whereas men experienced higher exhaustion in group independent practice. Overall, greater emotional exhaustion was associated with less control over work activities, working more hours, spending more time on administrative tasks and paperwork, seeing more managed care clients and fewer direct pay clients, and having to deal with more negative client behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
965.
Patricia Mortreau Reinhard Berndt 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2005,550(3):675-690
The traditional method used to determine the Uranium enrichment by nondestructive analysis is based on the “enrichment meter principle” [1]. It involves measuring the intensity of the 186 keV net peak area of 235U in “quasi-infinite” samples. A prominent factor, which affects the peak intensity, is the presence of gamma absorbing material (e.g., container wall, detector cover) between the sample and the detector. Its effect is taken into consideration in a commonly called “wall thickness” correction factor. Often calculated on the basis of approximations, its performance is adequate for small attenuation factors applicable to the case of narrow beams. However these approximations do not lead to precise results when wide non-parallel beams are attenuated through thick container walls.
This paper is dedicated to the calculation by numerical integration of the geometrical correction factor (Kwtc) which describes the effective mean path length of the radiation through the absorbing layer. This factor was calculated as a function of various measurement parameters (types and dimensions of the detector, of the collimator and of the shielding) for the most commonly used collimator shapes and detectors. Both coherent scattering (Rayleigh) and incoherent scattering (Compton) are taken into account for the calculation of the radiation interaction within the detector. 相似文献
966.
To what extent do frame‐building and frame‐setting processes manifest themselves in the interplay between online public discourse and traditional (offline) media discourse? Employing a content analysis of 206 online posts and 114 news reports regarding a sociopolitical incident in China, we test the associations and causal relationships between the salience of opinion frames and media frames. Online public opinion plays an important role in transforming the original local event into a nationally prominent issue. It also exerts a significant frame‐building impact on subsequent media reports but only in the early stage of coverage. However, the media are not passive in this two‐way process and adapt online frames as necessary. Although media coverage is the primary source of information for netizens, it does not set frames for online discourse. Noticeably, significant associations between concurrent opinion frames and media frames lend strong support to frame‐interacting effects. Discussion focuses on governmental influences in the frame‐building process and the potential of netizen autonomy to attenuate frame‐setting effects. 相似文献
967.
A Survey of Mobile Transactions 总被引:2,自引:1,他引:2
Patricia Serrano-Alvarado Claudia Roncancio Michel Adiba 《Distributed and Parallel Databases》2004,16(2):193-230
Transaction support is crucial in mobile data management. Specific characteristics of mobile environments (e.g. variable bandwidth, disconnections, limited resources on mobile hosts) make traditional transaction management techniques no longer appropriate. Several models for mobile transactions have been proposed but it is difficult to have an overview of all of them. This paper analyzes and compares several contributions to mobile transactions. The analysis distinguishes two groups of models. The first group includes proposals where transactions are completely or partially executed on mobile hosts. In this group we focus on ACID properties support. The second group considers transactions requested by mobile hosts and executed on the wired network. In this case, ACID properties are not compromised and focus is on supporting mobile host movements during transaction execution. Discussions pointing out limitations, interesting solutions and research perspectives complete this paper. 相似文献
968.
Julie Chen James A. Sherwood Patricia Buso Samuel Chow Darin Lussier 《Polymer Composites》2000,21(4):539-547
Despite demonstrated success in low volume aerospace and defense applications, structural composites remain at the periphery of high volume industries such as construction, automotive, and consumer goods because of long cycle times. Stamping provides a means of making composite sheet products at rates ten to a hundred times faster than any existing continuous fiber processes. However, to make composites stamping a viable process, one must understand how the combination of fabric architecture, tool design, and process conditions interact to produce a part free of wrinkling and tearing. In this paper, the effect of temperature, stamping rate, and boundary constraints on the material deformation is presented. The focus of this study is a co‐mingled glass/polypropylene fabric, in the form of a layer of unidirectional yarns held together by stitches. The results show that temperature variations have the greatest effect on deformation. In addition, a finite element model of parallel strips with linear constraints was shown to successfully simulate the sliding deformation or draw‐in of the stitched unidirectional material. 相似文献
969.
Hasen Alhebshi Kun Tian Lipsita Patnaik Rebecca Taylor Pavel Bezecny Callum Hall Patricia Anthonia Johanna Muller Nazila Safari Delta Patricia Menendez Creamer Constantinos Demonacos Luciano Mutti Mohamad Nidal Bittar Marija Krstic-Demonacos 《International journal of molecular sciences》2021,22(24)
Mutations in the p53 tumor suppressor are found in over 50% of cancers. p53 function is controlled through posttranslational modifications and cofactor interactions. In this study, we investigated the posttranslationally modified p53, including p53 acetylated at lysine 382 (K382), p53 phosphorylated at serine 46 (S46), and the p53 cofactor TTC5/STRAP (Tetratricopeptide repeat domain 5/ Stress-responsive activator of p300-TTC5) proteins in lung cancer. Immunohistochemical (IHC) analysis of lung cancer tissues from 250 patients was carried out and the results were correlated with clinicopathological features. Significant associations between total or modified p53 with a higher grade of the tumour and shorter overall survival (OS) probability were detected, suggesting that mutant and/or modified p53 acts as an oncoprotein in these patients. Acetylated at K382 p53 was predominantly nuclear in some samples and cytoplasmic in others. The localization of the K382 acetylated p53 was significantly associated with the gender and grade of the disease. The TTC5 protein levels were significantly associated with the grade, tumor size, and node involvement in a complex manner. SIRT1 expression was evaluated in 50 lung cancer patients and significant positive correlation was found with p53 S46 intensity, whereas negative TTC5 staining was associated with SIRT1 expression. Furthermore, p53 protein levels showed positive association with poor OS, whereas TTC5 protein levels showed positive association with better OS outcome. Overall, our results indicate that an analysis of p53 modified versions together with TTC5 expression, upon testing on a larger sample size of patients, could serve as useful prognostic factors or drug targets for lung cancer treatment. 相似文献
970.
Claudia I. Vallo Teresita R. Cuadrado Patricia M. Frontini 《Polymer International》1997,43(3):260-268
The deformation and fracture behaviour of some commercial acrylic bone cements have been investigated. Cements were characterized by gel permeation chromatography, dynamic mechanical analysis and scanning electron microscopy. The influence of liquid to powder ratio, curing temperature, strain rate and non-reacted monomer was analysed for one radiolucent cement. Results showed that the β transition activation process influences both deformation and fracture behaviour. Fracture surface stress whiteness revealed the presence of crazes as the main plastic deformation mechanism. Non-reacted monomer acted as a plasticizer leading to materials with lower yield strength, σy, that induces crack tip blunting and improves toughness. It appears that the presence of radiopacifier fillers also improves fracture toughness by promoting interactions between the crack and the second phase dispersion. © 1997 SCI. 相似文献