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排序方式: 共有108条查询结果,搜索用时 15 毫秒
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2.
Keri K. Stephens Renee L. Cowan Marian L. Houser 《Journal of Computer-Mediated Communication》2011,16(2):228-249
Relying on SIDE theory, this 2 × 2 experimental design tested the effects of adherence to organizational norms and interpersonal familiarity in e‐mail messages from both superior and subordinate perspectives. Results reveal that using norm‐congruent e‐mail messages account for over 50% of the variance in both superior and subordinate attitudes toward the message and between 30% and 56% of the variance in perceptions of source credibility. Data from the superiors indicate that norm congruent e‐mail messages account for 14.4% of the variance in message compliance. Results from subordinates reveal an interaction effect that is consistent with SIDE‐based predictions. Subordinates believe superiors are most likely to comply with e‐mail requests from unfamiliar subordinates that are crafted in a manner congruent with organizational norms. 相似文献
3.
Li YF Polgar O Okada M Esser L Bates SE Xia D 《Journal of molecular graphics & modelling》2007,25(6):837-851
The ATP-binding cassette protein ABCG2 is a member of a broad family of ABC transporters with potential clinical importance as a mediator of multidrug resistance. We carried out a homology and knowledge-based, and mutationally improved molecular modeling study to establish a much needed structural framework for the protein, which could serve as guidance for further genetic, biochemical, and structural analyses. Based on homology with known structures of both full-length and nucleotide-binding domains (NBD) of ABC transporters and structural knowledge of integral membrane proteins, an initial model of ABCG2 was established. Subsequent refinement to conform to the lipophilic index distributions in the transmembrane domain (TMD) and to the results of site-directed mutagenesis experiments led to an improved model. The complete ABCG2 model consists of two identical subunits facing each other in a closed conformation. The dimeric interface in the nucleotide-binding domain (NBD) involves a characteristic nucleotide sandwich and the interface in the TMD consists of the TM helices 1–3 of one subunit and the helices 5 and 6 of the other. The interface between the NBD and the TMD is bridged by the conserved structural motif between TM2 and TM3, the intracellular domain 1 (ICD1), and the terminal β-strand (S6) of the central β-sheet in the NBD. The apparent flexibility of the ICD1 may play a role in transmitting conformational changes from the NBD to the TMD or from the TMD to the NBD. 相似文献
4.
Blatchford Kate E.; Diamond Keri; Westbrook R. Frederick; McNally Gavan P. 《Canadian Metallurgical Quarterly》2005,119(4):1034
The authors used rats to study the impact of a history of opiate exposures on behavioral and autonomic responses to restraint stress. Brief restraint (30 min) provoked tachycardia and a pressor response, anxiety (as indexed by social interaction), grooming, and reduced exploration. The pressor response was reduced at 1 day, but not 7 days, after last opiate exposure; tachycardia was unaffected (Experiment 1). Stress-induced anxiety was potentiated 1 and 7 days after last opiate exposure (Experiment 2), and this potentiation was a function of dose (Experiment 3) and duration (Experiment 4) of opiate exposure. The results show that a history of opiate exposures alters vulnerability to stress and has implications for understanding coping, anxiety, and emotionality in former opiate users. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
This study directly compared the academic gains of reciprocal peer tutoring, nonreciprocal peer tutoring, and a waiting-list control group. Participants included 59 elementary students from second-, third-, and fourth-grade classrooms who performed below average on curriculum-based measurement (CBM) math probes. Students involved in peer tutoring were trained to tutor basic math facts using a constant time delay procedure. Results indicated that the two types of peer tutoring produced comparable gains in basic math facts. Furthermore, both types of peer tutoring produced substantially larger academic gains than the waiting-list control group, demonstrating at-risk students can successfully tutor each other. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Synthesis of Novel Phosphonic‐Type Activity‐Based Probes for Neutrophil Serine Proteases and Their Application in Spleen Lysates of Different Organisms
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Dr. Renata Grzywa Dr. Ewa Burchacka Maria Łęcka Dr. Łukasz Winiarski Maciej Walczak Agnieszka Łupicka‐Słowik Dr. Magdalena Wysocka Prof. Timo Burster Dr. Kamila Bobrek Dr. Keri Csencsits‐Smith Prof. Adam Lesner Dr. Marcin Sieńczyk 《Chembiochem : a European journal of chemical biology》2014,15(17):2605-2612
Neutrophils are a type of granulocyte important in the “first line of defense” of the innate immune system. Upon activation, they facilitate the destruction of invading microorganisms by the production of superoxide radicals, as well as the release of the enzymatic contents of their lysozymes. These enzymes include specific serine proteases: cathepsin G, neutrophil elastase, proteinase 3, as well as the recently discovered neutrophil serine protease 4 (NSP4). Under normal conditions, the proteolytic activity of neutrophil proteases is tightly regulated by endogenous serpins; however, this mechanism can be subverted during tissue stress, thereby resulting in the uncontrolled activity of serine proteases, which induce chronic inflammation and subsequent pathology. Herein, we describe the development of low‐molecular‐weight activity‐based probes that specifically target the active sites of neutrophil proteases. 相似文献
7.
Managing database server performance to meet QoS requirements in electronic commerce systems 总被引:1,自引:0,他引:1
Patrick Martin Wendy Powley Hoi-Ying Li Keri Romanufa 《International Journal on Digital Libraries》2002,3(4):316-324
The performance of electronic commerce systems has a major impact on their acceptability to users. Different users also demand
different levels of performance from the system, that is, they will have different Quality of Service (QoS) requirements. Electronic commerce systems are the integration of several different types of servers and each server must
contribute to meeting the QoS demands of the users. In this paper we focus on the role, and the performance, of a database server within an electronic commerce system.
We examine the characteristics of the workload placed on a database server by an electronic commerce system and suggest a
range of QoS requirements for the database server based on this analysis of the workload. We argue that a database server
must be able to dynamically reallocate its resources in order to meet the QoS requirements of different transactions as the
workload changes. We describe Quartermaster, which is a system to support dynamic goal-oriented resource management in database
management systems, and discuss how it can be used to help meet the QoS requirements of the electronic commerce database server.
We provide an example of the use of Quartermaster that illustrates how the dynamic reallocation of memory resources can be
used to meet the QoS requirements of a set of transactions similar to transactions found in an electronic commerce workload.
We briefly describe the memory reallocation algorithms used by Quartermaster and present experiments to show the impact of
the reallocations on the performance of the transactions.
Published online: 22 August 2001 相似文献
8.
Keri Schreiner 《Computer Graphics and Applications, IEEE》2008,28(1):12-17
The field of games aimed at social change is young and ripe with opportunity, and several recent announcements of corporate/public-sector partnerships to develop such games are further fueling hopes for its success. These games raise awareness of important social issues in two ways: through "engaging and meaningful game play" and innovative, successful, and often large-scale distribution techniques. Such games are typically low-budget, grassroots creations distributed virally. The focus is on reaching new audiences, exploring innovative distribution options, and drawing attention to an issue. 相似文献
9.
The impacts of large-scale, episodic sediment resuspension on the cycling of polychlorinated biphenyl congeners (PCBs) were examined using a spatially coordinated air and water sampling strategy conducted in southern Lake Michigan in the late winters of 1998, 1999, and 2000. We found no significant temporal changes in gas phase, dissolved phase, or suspended sediment PCB concentrations despite large-scale seasonal storms occurring before and after sampling campaigns. Only gas phase and suspended sediment PCBs varied spatially. Higher total suspended material (TSM) concentrations and fraction organic carbon (foc) were measured at sampling stations located in the near-shore region of southern Lake Michigan than at open-water sampling stations. Gas phase concentrations (ΣPCBg) were higher in the west (0.436 ± 0.200 ng/m3, n = 11) and south (0.408 ± 0.286 ng/m3, n = 5) than the east (0.214 ± 0.082 ng/m3, n = 10) and central (0.253 ± 0.145 ng/m3, n = 8) regions of southern Lake Michigan. Dissolved phase concentrations (ΣPCBd) averaged 0.18 ± 0.024 ng/L (n = 52); suspended sediment concentrations (ΣPCBs) accounted for between 4% and 72% (23 ± 4%, n = 52) of the total ΣPCB concentrations (ΣPCBT = ΣPCBd + ΣPCBs). Despite no consistent temporal variations in both dissolved phase or suspended sediment ΣPCB concentrations, there were temporal and spatial variations in the distribution shift between phases that can be linked to sediment resuspension, not a state of equilibrium. Specifically, our analysis suggests sediment resuspension results in preferential sorption of heavier, more chlorinated PCB congeners. 相似文献
10.
The process by which metamemory and academic causal attributions relate to recall was examined with hierarchical multiple regression analyses. Several alternative conceptualizations of metamemory were used: general metamemory unrelated to the specific task; task-specific metamemory; memory monitoring; and both general and task-specific attributions. In order to examine the additive benefits of strategy and monitoring instructions, 81 4th graders were assigned to 1 of 4 instructional conditions: Strategy Only, Process Monitoring Only, Strategy Plus Process Monitoring, or Practice-Control group. Regression analyses indicated that the relationships between metamemory and recall depended on how metamemory was assessed and on the timing of the child's engagement with the recall task. Whereas general metamemory was significantly related to recall on the posttest and near-transfer tasks, task-specific metamemory became more relevant for transfer. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献