Impression valence constrains social explanations: The case of discounting versus conjunction effects.

Discounting refers to a reduction in explanation plausibility in light of another explanation, whereas conjunction effects refer to an increase in plausibility of explanations judged in combination rather than in isolation. Explanation compatibility moderates these effects, such that discounting is greater for incompatible explanations and conjunction effects are greater for compatible explanations. Three experiments examined whether this effect reflects perceptions regarding (a) the prior statistical association of causal factors, (b) the sharing of common causal mechanisms, or (c) coherence with regard to global impressions. Results indicated that impression valence predicts and also directly influences discounting and conjunction effects independent of covariation and mechanism, underscoring the pervasive impact of impressions on attributions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Item and associative memory in amnestic mild cognitive impairment: Performance on standardized memory tests.

The earliest neuroanatomical changes in amnestic mild cognitive impairment (aMCI) involve the hippocampus and entorhinal cortex, structures implicated in the integration and learning of associative information. The authors hypothesized that individuals with aMCI would have impairments in associative memory above and beyond the known impairments in item memory. A group of 29 individuals with aMCI and 30 matched control participants were administered standardized tests of object-location recall and symbol-symbol recall, from which both item and associative recall scores were derived. As expected, item recall was impaired in the aMCI group relative to controls. Associative recall in the aMCI group was even more impaired than was item recall. The best group discriminators were measures of associative recall, with which the sensitivity and specificity for detecting aMCI were 76% and 90% for symbol-symbol recall and were 86% and 97% for object-location recall. Associative recall may be particularly sensitive to early cognitive change in aMCI, because this ability relies heavily on the medial temporal lobe structures that are affected earliest in aMCI. Incorporating measures of associative recall into clinical evaluations of individuals with memory change may be useful for detecting aMCI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Control of morphology in inert-gas condensation of metal oxide nanoparticles

We report preparation conditions to obtain different morphologies of as-deposited refractory metal-oxide nanoparticles using inert-gas condensation with CO₂ laser heating. The micrometer-scale morphology of the nanoparticles depends on the specific metal oxide, the buffer gas composition and pressure, and the target-to-substrate distance. These parameters control the extent to which a plume of nonagglomerated nanoparticles can reach a deposition substrate. Buffer gas pressure has the largest influence for a given material, with lower pressures producing a dense columnar morphology and higher pressures resulting in an open networked morphology. An estimate based on the geometry of the gas-phase plume and experimental results for Y₂O₃ nanoparticles produced in 4 Torr N₂ gives a critical concentration of tens of nanoparticles per μm³ for the transition of agglomerates versus isolated nanoparticles reaching a deposition substrate.     

A High-Speed Optical Multidrop Bus for Computer Interconnections

Signal integrity constraints of high-speed electronics have made multidrop electrical buses infeasible. This high-speed alternative uses hollow metal waveguides and pellicle beam splitters that interconnect modules attached to the bus. With 1 mW of laser power, the bus can interconnect eight modules at 10 Gbps per channel and achieves an aggregate bandwidth of more than 25 Gbytes per second with 10-bit-wide signaling paths.     

Impact of receive amplifier signal coupling on MIMO system performance

This paper uses a detailed model of multiple input multiple output (MIMO) systems to explore the impact of signal coupling in the receiver front end on communication capacity. The model is applied to assess the performance of a MIMO system with two transmit and receive antennas in a simulated multipath environment for different amplifier coupling levels. The results show that in practical scenarios where simple impedance matching techniques are used, the circuit coupling can reduce the signal-to-noise ratio at the receiver and therefore degrade the achievable MIMO capacity.     

Development of a Wireless Pressure Measurement System Using Interdigitated Capacitors

Remote pressure monitoring is of particular importance in medical and environmental applications as it is less labour intensive, safer and offers peace of mind to the general public. To meet this demand, a prototype system has been developed and used to evaluate thick-film pressure sensors with an oxide dielectric layer. The circuit is based on the principle of capacitance-frequency-voltage conversion and has been designed to minimize power consumption. Each device was tested under hydrostatic pressure in the range 0-17 kPa and assessed in terms of sensitivity, hysteresis, repeatability, creep and temperature effects. The results show that this approach may be used for the fabrication of cost effective, reliable devices for wireless pressure sensing applications