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51.
The identification of targets in visual search arrays may be improved by suppressing competing information from the surrounding distractor items. The present study provided evidence that this hypothetical filtering process has a neural correlate, the N2pc component of the event-related potential waveform. The N2pc was observed when a target item was surrounded by competing distractor items but was absent when the array could be rejected as a nontarget on the basis of simple feature information. In addition, the N2pc was eliminated when filtering was discouraged by removing the distractor items, making the distractors relevant, or making all items within an array identical. Combined with previous topographic analyses, these results suggest that attentional filtering occurs in occipital cortex under the control of feedback from higher cortical regions after a preliminary feature-based analysis of the stimulus array. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
Vinit D. Makwana L. Javier Garces Jia Liu Jun Cai Young-Chan Son Steven L. Suib 《Catalysis Today》2003,85(2-4):225-233
Manganese oxides having a tunnel structure (OMS-2) have been utilized as selective catalysts for alcohol oxidation. In this study manganese oxide catalysts were synthesized in different media and modified by exchanging the tunnel cation by H+, using acid treatment or exchanging with NH4+ followed by thermolysis. Various alcohol oxidations were performed using these catalysts to ascertain the influence of synthesis method on their activity. A correlation is made between lattice oxygen instability and activity of the catalysts, which indicates involvement of the lattice oxygen in the mechanism. The exchange of the tunnel cation with the smaller H+ ions leads to weakening of the Mn–O bond, as verified by temperature programmed desorption (TPD) results. Only the chemisorbed oxygen on the surface (O−) and the lattice oxygen in the layers close to the surface is involved in the oxygen transfer during the reaction. 相似文献
53.
The aim of this study was to demonstrate a correlation between the clinical assessment of narcissistic personality disorder in children and underlying self and object relationships. D. Westen's Social Cognition and Object Relations Scale for the Thematic Apperception Test (1995; D. Westen, N. Lohr, K. Silk, K. Kerber, & S. Goodrich, 1985) was used to compare the object representations of two groups of referred latency-aged children, one for whom narcissistic issues were thought to be primary. Support for the clinical literature, which describes these children as lacking in empathy, struggling with self-esteem regulation, and in poor control of their impulses or aggression, was found. Additionally, a tendency to have a vulnerable sense of identity and to be preoccupied with seeking out and developing relationships with others was found to differentiate these children from peers with similar behavioral and diagnostic profiles. Results obtained have potential implications for the assessment and treatment of narcissistically disturbed children. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
54.
Arun Chandrasekhar Steven Brebels Serguei Stoukatch Eric Beyne Walter De Raedt Bart Nauwelaers 《Microelectronics Reliability》2003,43(3):351-357
At frequencies beyond 1 GHz, every component of the IC package contributes to the RF performance, whether required or not. In this work, we study the effects of packaging materials namely, the substrate and the globtop/underfill material on RF performance. We have measured interconnects on two area-array CSPs, the ball grid array and the polymer stud grid array using IMEC’s MCM-D technology. The measurements on the package interconnect show that the losses in the package substrate material account for about 50% of the total losses at 1.8 GHz and this drops to less than 20% at 5.2 GHz. The losses due to impedance mismatch dominate the losses especially below 10 GHz and considerable improvement in performance cannot be obtained by using an improved/expensive substrate. The other study is about the influence of globtop/underfill materials on wirebonds (through 3D EM simulations) as well as on standard 50 Ω MCM-D transmission lines (through experiments). While a higher value of dielectric constant of the globtop/underfill material is better on wirebonds, the influence of loss tangent is felt only above values of 0.1. The influence of seven different globtop/undefill materials on 50 Ω transmission lines has been used to extract their dielectric constant and loss tangent values at 30 GHz. These results are very valuable since one can hardly find the properties of globtop/underfill materials beyond 1 GHz. 相似文献
55.
W. S. Gutowski Sheng Li Con Filippou Pamela Hoobin Steven Petinakis 《The Journal of Adhesion》2003,79(5):483-519
Part I of this paper reviewed the theoretical principles of the macromolecular design of polymer interface/interphase systems for obtaining maximum adhesion and fracture performance of adhesively bonded assemblies. In Part II a novel, relatively simple and industry-feasible technology for surface-grafting connector molecules is demonstrated and discussed in detail and supported by a range of experimental examples. It is shown, in agreement with contemporary theory, that the use of chemically attached graft chemicals of controlled spatial geometry and chemical functionality enables a significant increase in the strength and fracture energy of the interphase, to the point of cohesive fracture of the substrate, or that of an adjacent medium such as adhesive, elastomer, or other material. This occurs even after prolonged exposure of investigated systems to adverse environments such as hot water. 相似文献
56.
Teri Linda; Truax Paula; Logsdon Rebecca; Uomoto Jay; Zarit Steven; Vitaliano Peter P. 《Canadian Metallurgical Quarterly》1992,7(4):622
The Revised Memory and Behavior Problems Checklist (RMBPC), a 24-item, caregiver-report measure of observable behavioral problems in dementia patients, provides 1 total score and 3 subscale scores for S problems (memory-related, depression, and disruptive behaviors) and parallel scores for caregiver reaction. Data were obtained from 201 geriatric Ss and their caregivers. Factor analysis confirmed 3 1st-order factors, consistent with subscales just named, and 1 general factor of behavioral disturbance. Overall scale reliability was good, with alphas of .84 for S behavior and .90 for caregiver reaction. Subscale alphas ranged from .67 to .89. Validity was confirmed through comparison of RMBPC scores with well-established indexes of depression, cognitive impairment, and caregiver burden. The RMBPC is recommended as a reliable and valid tool for the clinical and empirical assessment of behavior problems in dementia Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
57.
Engineering design involves the satisfaction of customer needs, These needs, whether explicitly stated or only implicitly defined, must be translated into a set of specifications for a product. The subsequent stages of design, fabrication, and maintenance are dedicated to the fulfillment of these specifications. The task of concurrent design is to ensure that the product performs as specified, with fidelity and consistency. Ensuring product performance is the objective of quality assurance. Software packages can be developed to assist in this effort, ranging from the initial phase of requirements definition to production control and maintenance. 相似文献
58.
Florsheim Paul; Behling Steven; South Mikle; Fowles Timothy R.; DeWitt John 《Canadian Metallurgical Quarterly》2004,1(2):126
This study adopted a systemic approach to studying intervention efforts with delinquent youth, examining the association between several youth corrections programs and adult criminal outcomes. Two studies were designed to use juvenile and adult court records to evaluate the effectiveness of treatment programs provided to delinquent youth in state custody. The results of Study 1 suggested that court-recorded delinquent charges can be used to estimate delinquency severity. The results of Study 2 presented a discouraging but not entirely unexpected illustration of the effectiveness of intervention efforts among delinquent youth. It was found that time spent in juvenile detention facilities, work programs, and group homes was associated with negative adult criminal outcomes. No links between time spent in youth corrections programs and positive outcomes were identified. Implications for future program evaluation efforts are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
59.
Steven Conner 《电子设计技术》2004,11(11):90-90
目前的第一代无线局域网(WLAN)仅仅用来简单地取代有线,即只是用来消除主要家庭娱乐系统或办公设备部署采用过多线缆所引起的混乱.而实际上,无线通信的优势远远不止这一点.摆脱线缆的束缚之后,设备间可能的连接方式将大量增加. 相似文献
60.