Strategy effects counteract distractor inhibition: Negative priming with constantly absent probe distractors.

It is an accepted, albeit puzzling finding that negative priming (NP) hinges on the presence of distractors in probe displays. In three experiments without probe distractors, the authors yielded evidence that response-biasing processes based on the contingency between prime and probe displays may have caused this finding. It is argued that it is of help in standard NP experiments to process the distractor in the prime display in order to prepare the response to the probe target. When this contingency was removed (Experiments 2 and 3), NP was reliably observed without probe distractors, whereas no NP emerged if the design contained the typical contingency (Experiment 1). For this reason, the data suggest that the absence of NP, which is usually observed under these conditions, may be due to a contingency-based component. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Imbibition test in a clay powder (MX-80 bentonite)

The MX-80 bentonite is a reference material for studies in clay barriers. This paper aims to present an investigation of the behaviour of such a material during an infiltration test from the bottom in oedometric conditions. Using dual-energy γ radiation technique, time variations of moisture content are measured at various locations along the clay sample. The transport of water occurring in this experiment can be described by the classical diffusion equation in terms of the Boltzmann variable. A parameter of hydraulic diffusivity is obtained with the Matano's method.Two fluid transport mechanisms govern the phenomena: imbibition of the microporosity in the clay grains and capillary imbibition in the mesoporosity around the grains. The competition between these two mechanisms will be put into relief by modelling the distribution of the water between and inside the bentonite grains. A clogging behaviour of the mesopores during the imbibition process will allow to explain the surprising decrease in hydraulic diffusivity.     

MAC Layer Concepts to Support Space Division Multiple Access in OFDM based IEEE 802.16

Advanced antenna technologies and algorithms have been developed during the last years. But until today, advanced antenna algorithms in the physical layer and the modes of operation in medium access layers have not been integrated in modern wireless systems. As one of the first standards the metropolitan area network IEEE 802.16 provides means to support smart antenna techniques.After a detailed introduction of the medium access control layer this article outlines the support of space division multiple access (SDMA) techniques by the wireless metropolitan area network IEEE 802.16. New concepts are introduced that allow and further optimize the use of SDMA techniques brought by intelligent antennas. First, the possibility to enable SDMA in the IEEE 802.16a-2003 protocol is investigated, and second the support of SDMA in the revised 802.16-2004 standard is elaborated in detail. To overcome current limitations of 802.16a-2003, an enhanced control structure is introduced in 802.16-2004 that masters a concurrent transmission and reception of data to/from several different subscriber stations. The approach facilitates a fully flexible structure which significantly improves system capacity. Christian P. Hoymann received his Diploma degree in electrical engineering from RWTH Aachen University in 2002. Before he served a student internship at SIEMENS Corporate Research, Princeton, USA. Since 2002 he is employed as a Research Assistant at the Chair of Communication Networks (ComNets) of RWTH Aachen University where he is working towards his Ph.D. degree.He worked in the fields of traffic engineering and dimensioning of GSM/GPRS networks together with his project partners at D2 Vodafone. He was actively involved in the IST-STRIKE project where smart antenna systems had been integrated in Metropolitan Area Networks. His current research interests include the optimization of MANs especially in consideration of smart antenna technologies such as SDMA and relaying technologies such as Mesh.Mr. Hoymann has published several conference and journal papers and was actively involved in the standardization of SDMA technologies for IEEE 802.16.     

Social psychology and changing technologies: Reality versus caricature.

Comments on D. Kipnis's (see record 199707781-001) article that critically analyzes social psychology's assumption that psychological states can explain social behavior. The present authors point out that there are many sources in social psychology that, in fact, have revealed a vibrant and rigorous discipline in which, contrary to Kipnis's "caricature," explanations are routinely empirically questioned, variables are directly manipulated and measured, often along with their physiological and neuro-electrical correlates, and multivariate approaches address the separate and joint impact of multiple predictors on multiple dependent variables. It is also noted that Kipnis ignored social psychological research in which experimenters have assessed the physiological correlates of cognitive states. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Instance-Specific Accelerators for Minimum Covering

This paper presents the acceleration of minimum-cost covering problems by instance-specific hardware. First, we formulate the minimum-cost covering problem and discuss a branch & bound algorithm to solve it. Then we describe instance-specific hardware architectures that implement branch & bound in 3-valued logic and use reduction techniques similar to those found in software solvers. We further present prototypical accelerator implementations and a corresponding design tool flow. Our experiments reveal significant raw speedups up to five orders of magnitude for a set of smaller unate covering problems. Provided that hardware compilation times can be reduced, we conclude that instance-specific acceleration of hard minimum-cost covering problems will lead to substantial overall speedups.     

Stressors, resources, and strain at work: A longitudinal test of the triple-match principle.

[Correction Notice: An erratum for this article was reported in Vol 92(1) of Journal of Applied Psychology (see record 2006-23339-016). The issue number at the upper left corner of the title page (p. 1359) is wrongly stated as 5 rather than 6. Furthermore, in Table 1 (p. 1362), the value in Column 12, Row 4 (Emo resources) should be -.07 rather than -0.7.] Two longitudinal studies investigated the issue of match between job stressors and job resources in the prediction of job-related strain. On the basis of the triple-match principle (TMP), it was hypothesized that resources are most likely to moderate the relation between stressors and strains if resources, stressors, and strains all match. Resources are less likely to moderate the relation between stressors and strains if (a) only resources and stressors match, (b) only resources and strains match, or (c) only stressors and strains match. Resources are least likely to moderate the relation between stressors and strains if there is no match among stressors, resources, and strains. The TMP was tested among 280 and 267 health care workers in 2 longitudinal surveys. The likelihood of finding moderating effects was linearly related to the degree of match, with 33.3% of all tested interactions becoming significant when there was a triple match, 16.7% when there was a double match, and 0.0% when there was no match. Findings were most consistent if there was an emotional match or a physical match. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pulse-driven Josephson digital/analog converter [voltage standard]

The authors have designed and demonstrated a pulse-driven Josephson digital/analog converter. When used as a programmable voltage standard, this device can synthesize metrologically accurate ac waveforms as well as stable dc voltages. We show through simulations that Josephson quantization produces a nearly ideal quantization noise spectrum when a junction is driven with a typical waveform produced by a digital code generator. This technique has been demonstrated in preliminary experiments with arrays of 1000 junctions clocked at frequencies up to 6 Gb/s, where sine waves of a few millivolts in amplitude were synthesized at frequencies up to 1 MHz