Hemispheric specialization in selective attention and short-term memory: a fine-coarse model of left- and right-ear disadvantages.

Serial short-term memory is impaired by irrelevant sound, particularly when the sound changes acoustically. This acoustic effect is larger when the sound is presented to the left compared to the right ear (a left-ear disadvantage). Serial memory appears relatively insensitive to distraction from the semantic properties of a background sound. In contrast, short-term free recall of semantic-category exemplars is impaired by the semantic properties of background speech and is relatively insensitive to the sound’s acoustic properties. This semantic effect is larger when the sound is presented to the right compared to the left ear (a right-ear disadvantage). In this paper, we outline a speculative neurocognitive fine-coarse model of these hemispheric differences in relation to short-term memory and selective attention, and explicate empirical directions in which this model can be critically evaluated

Improvement of indoor VLC network downlink scheduling and resource allocation

Indoor visible light communications (VLC) combines illumination and communication by utilizing the high-modulation-speed of LEDs. VLC is anticipated to be complementary to radio frequency communications and an important part of next generation heterogeneous networks. In order to make the maximum use of VLC technology in a networking environment, we need to expand existing research from studies of traditional point-to-point links to encompass scheduling and resource allocation related to multi-user scenarios. This work aims to maximize the downlink throughput of an indoor VLC network, while taking both user fairness and time latency into consideration. Inter-user interference is eliminated by appropriately allocating LEDs to users with the aid of graph theory. A three-term priority factor model is derived and is shown to improve the throughput performance of the network scheduling scheme over those previously reported. Simulations of VLC downlink scheduling have been performed under proportional fairness scheduling principles where our newly formulated priority factor model has been applied. The downlink throughput is improved by 19.6% compared to previous two-term priority models, while achieving similar fairness and latency performance. When the number of users grows larger, the three-term priority model indicates an improvement in Fairness performance compared to two-term priority model scheduling

Perceptual-gestural (mis)mapping in serial short-term memory: The impact of talker variability

The mechanisms underlying the poorer serial recall of talker-variable lists (e.g., alternating female–male voices) as compared with single-voice lists were examined. We tested the novel hypothesis that this talker variability effect arises from the tendency for perceptual organization to partition the list into streams based on voice such that the representation of order maps poorly onto the formation of a gestural sequence-output plan assembled in support of the reproduction of the true temporal order of the items. In line with the hypothesis, (a) the presence of a spoken lead-in designed to further promote by-voice perceptual partitioning accentuates the effect (Experiments 1 and 2); (b) the impairment is larger the greater the acoustic coherence is between nonadjacent items: Alternating-voice lists are more poorly recalled than four-voice lists (Experiment 3); and (c) talker variability combines nonadditively with phonological similarity, consistent with the view that both variables disrupt sequence output planning (Experiment 4). The results support the view that serial short-term memory performance reflects the action of sequencing processes embodied within general-purpose perceptual input-processing and gestural output-planning systems

Retrieval from memory: Vulnerable or inviolable?

We show that retrieval from semantic memory is vulnerable even to the mere presence of speech. Irrelevant speech impairs semantic fluency—namely, lexical retrieval cued by a semantic category name—but only if it is meaningful (forward speech compared to reversed speech or words compared to nonwords). Moreover, speech related semantically to the retrieval category is more disruptive than unrelated speech. That phonemic fluency—in which participants are cued with the first letter of words they are to report—was not disrupted by the mere presence of meaningful speech, only by speech in a related phonemic category, suggests that distraction is not mediated by executive processing load. The pattern of sensitivity to different properties of sound as a function of the type of retrieval cue is in line with an interference-by-process approach to auditory distraction

Commentary : Donepezil enhances understanding of degraded speech in Alzheimer's disease

Non peer reviewe

Congestion-gradient driven transport on complex networks

We present a study of transport on complex networks with routing based on local information. Particles hop from one node of the network to another according to a set of routing rules with different degrees of congestion awareness, ranging from random diffusion to rigid congestion-gradient driven flow. Each node can be either source or destination for particles and all nodes have the same routing capacity, which are features of ad-hoc wireless networks. It is shown that the transport capacity increases when a small amount of congestion awareness is present in the routing rules, and that it then decreases as the routing rules become too rigid when the flow becomes strictly congestion-gradient driven. Therefore, an optimum value of the congestion awareness exists in the routing rules. It is also shown that, in the limit of a large number of nodes, networks using routing based on local information jam at any nonzero load. Finally, we study the correlation between congestion at node level and a betweenness centrality measure.Comment: 11 pages, 8 figure

Optimal routing on complex networks

We present a novel heuristic algorithm for routing optimization on complex networks. Previously proposed routing optimization algorithms aim at avoiding or reducing link overload. Our algorithm balances traffic on a network by minimizing the maximum node betweenness with as little path lengthening as possible, thus being useful in cases when networks are jamming due to queuing overload. By using the resulting routing table, a network can sustain significantly higher traffic without jamming than in the case of traditional shortest path routing.Comment: 4 pages, 5 figure

Dynamic cognitive control of irrelevant sound:Increased task engagement attenuates semantic auditory distraction

Two experiments investigated reactive top-down cognitive control of the detrimental influence of spoken distractors semantically related to visually-presented words presented for free recall. Experiment 1 demonstrated that an increase in focal task-engagement—promoted experimentally by reducing the perceptual discriminability of the visual target-words—eliminated the disruption by such distracters of veridical recall and also attenuated the erroneous recall of the distracters. A recall instruction that eliminates the requirement for output-monitoring was used in Experiment 2 to investigate whether increased task-engagement shields against distraction through a change in output-monitoring processes (back-end control) or by affecting the processing of the distracters during their presentation (front-end control). Rates of erroneous distracter-recall were much greater than in Experiment 1 but both erroneous distracter-recall and the disruptive effect of distracters on veridical recall were still attenuated under reduced target-word discriminability. Taken together, the results show that task-engagement is under dynamic strategic control and can be modulated to shield against auditory distraction by attenuating distracter-processing at encoding thereby preventing distracters from coming to mind at test

Structure of permethyltantalocenephenylmethanecarbothialdehyde hydride, (η^5-C_5Me_5)_2Ta(η^2-SCHCH_2C_6H_5)H

Hydridobis( 7] 5-pentamethylcyclopentadienyl) (phenylmethanecarbothialdehyde-kC,kS)tantalum C_(28)H_(39)STa, Mr= 588.63, monoclinic, P2_1 c, ɑ = 15.729 (5), b = 10.203 (2), c = 17.599 (5) Å, β = 116.18 (2)º , v = 2535 (1) Å^3, z = 4, D_x = 1.54 g cm^(-3), λ(Mo Kɑ) = 0.71073 A, μ = 46.6 cm^(-1), F(000) = 1184, room temperature (297 K), R = 0.068 for 2333 reflections with F_o^2 > 0, R = 0.054 for 2179 with F_o^2 > 3σ(F_o^2). The structure is disordered, with two enantiomeric molecules occupying the same crystallographic site. For the major component, the thioaldehyde ligand has an S-C bond length of 1.86 (2) Å. The ligand is bonded to the Ta center with a Ta-S bond distance of 2.418 (9) Å and a Ta-C bond distance of 2.28 (2) Å