Abstract Stimuli Associated With Threat Through Conditioning Cannot Be Detected Preattentively.

Studies of anxiety suggest that threat stimuli can be identified preattentively, but this conclusion is questionable because of possible low-level perceptual confounds. Two experiments used visual search tasks in which abstract shapes were conditioned to carry neutral or negative valence. Experiment 1 found generally faster responses to threat-associated abstract stimuli but no evidence that they were detected preattentively, irrespective of trait anxiety level. A similar pattern was found in Experiment 2, in which individuals high in snake or spider fear showed no evidence of preattentive detection of abstract stimuli associated with their feared object. In contrast, implicit behavioral measures showed significant effects of conditioning, demonstrating that targets associated with threat were negatively evaluated in these experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The synthesis of elastin, collagen, and glycosaminoglycans by high density primary cultures of neonatal rat aortic smooth muscle. An ultrastructural and biochemical study

Primary cultures of neonatal rat aortic smooth muscle cells inoculated at high densities (1 X 10(6) cells/25 cm2 Falcon flask) with adequate nutrient media and pH control grow rapidly and form multilayers of cells with typical "hill and valley" organization. After 10 days growth insoluble elastin formation could be visualized by phase contrast microscopy as small particles which grew rapidly to become larger irregular refractile aggregates and later coalesced to form larger aggregates and small fibres. With light and electronmicroscopy, elastin was the predominant matrix protein formed, with the "hill regions" of cultures containing abundant elastin aggregates and some collagen. In 2-week-old cultures differentiation could be observed within the cell multilayer. The older deeper cells contained more protein synthesis organelles and myofilaments and were in close association with large often coalescing elastin aggregates; compared to younger more superficial cells which contained more free polyribosomes less myofilaments, and were associated with fewer and small elastin aggregates. In older cultures this differentiation was not apparent; the cells contained many myofilaments, dense bodies, and lysosomes. Elastin aggregates and newly formed elastic fibres were abundant in the matrix. Quantitative analysis of insoluble elastin formation in the cell layer during the 4-week culture period indicated continuous biosynthesis and deposition which paralleled that of desmosine formation. Amino-acid analysis of a hot alkali insoluble residue (regarded as elastin) from 30-day-old cultures gave a profile identical with neonatal rat aortic elastin in vivo. Insoluble collagen formation in the cell layer tended to plateau after the log phase of growth was completed (10 days). Proteoglycans were found predominantly in the supernatant media. Glycosaminoglycan analysis revealed a profile of dermatan sulphate (32%), chondroitin 4-sulphate (43%), keratan and heparan sulphate (30%), with only a trace of hyaluronic acid. This study indicates that primary cultures of neonatal rat aortic smooth muscle cells remain differentiated in culture and have the unique capacity to continue to synthesize and deposit large amounts (mg) of insoluble elastin which aggregate and from elastic fibres in vitro.     

Improving cooking efficiencies: Barbecuing reassessed

Barbecuing is becoming increasingly popylar, yet is notoriously energy-inefficient. So the factors affecting the thermal efficiency of this process, as well as the quality of the food so cooked, especially in Nigeria, have been investigated. Design recommendations are presented.     

Urban Simulacra: London

As the digital revolution deepens and pervades every aspect of daily life, virtual realities begin to penetrate one another in a multiplicity of ways. The amount of sensing data being compiled on the city grows, enabling the construction of virtual realities that can, in turn, be transformed for diverse purposes. Here, Michael Batty and Andrew Hudson-Smith from the Centre for Advanced Spatial Analysis, University College London, outline how they went about the construction of a virtual city in central London. A conventional 3-D-GIS/CAD model was used as the basis on which to build a digital realm in which designers are cast as avatars and populations as agents, so as to define new ways in which to understand and plan the city. Copyright © 2005 John Wiley & Sons, Ltd.     

Electrothermal Monte Carlo Simulations of InGaAs/AlGaAs HEMTs

Results from the application of our electrothermal simulator to n-type 0.15 μm gate In_0.15Ga_0.85As-Al_0.28Ga_0.72As HEMT structures are presented. The simulator involves an iterative procedure which alternately solves the Heat Diffusion Equation (HDE) and executes a Monte Carlo electronic transport algorithm. The net thermal flux generated during each Monte Carlo stage, calculated from the net rate of phonon emission, is fed into the thermal solution; the resulting temperature map is then used in the following Monte Carlo iteration. The HDE is solved through application of a novel analytical thermal resistance matrix technique which allows calculation of temperatures solely within the region of interest while including the large-scale boundary conditions. A novel charge injection scheme is applied for the treatment of side ohmic contacts, which avoids anomalous generation of thermal flux in adjacent regions. The characteristic ‘thermal droop’ is found in the I-V characteristics of the simulated device. Associated temperature distributions are shown to be spatially non-uniform with peak values and spatial locations dependent upon bias and the length of the containing die. Electron drift velocities and energies along the HEMT channel exhibit the largest shift on the inclusion of thermal self-consistency below the drain end of the gate, not at the location of the temperature peak.     

Apparent thermal conductivity of glass-fibre insulant: effects of compression and moisture content

The line source thermal probe technique was validated and used to measure the apparent thermal conductivities of commercially available dry and moist glass-fibre blankets under various compressions. For the dry insulant, a minimum apparent thermal conductivity of 0·039 W m^?1 K^?1 occurred at ～ 20°C for optimal values of bulk density—and consequently of volume voidage—of 0·45 kg m^?3 and 0·985, respectively. Observations for the apparent thermal conductivities of moist insulants did not agree with theoretical predictions but were corroborated by the experimental results of other investigators.     

A water requirement model for salt gradient solar ponds

A model for predicting the salt gradient solar pond (SGSP) area that could be maintained with a given water supply is presented together with several specific applications. For example, based on 30-year average water flows, the model predicts that 1.93 × 10⁹ m² (477,000 acres) of solar ponds, 1.02 × 10⁹ m² (253,000 acres) of evaporation ponds to recycle salt, and 0.51 × 10⁹ m² (125,000 acres) of freshwater storage reservoirs could be maintained at the Great Salt Lake of Utah. Water use requirements per unit of electrical energy from solar ponds are calculated as 600,000 m³/MW·yr. This is roughly 30 times the water evaporated per unit of electrical energy from coal-fired generating plants using wet cooling towers, but substantially less than water evaporation losses per unit of electrical energy produced from typical hydropower dams and reservoirs. It is concluded that water use requirements for solar ponds, although not necessarily prohibitive, are substantial; and in many locations may be the physical factor that limits solar pond development.     

Spatial aggregation in gravity models: 2. One-dimensional population density models

"This paper, the second of four, is concerned with applying a methodology for analysing the spatial aggregation problem in gravity models outlined in the first paper. The methodology is based on a consistent framework for linking measures of pattern in interaction data to the derivation and estimation of related interaction models using spatial information. In this quest, a link is forged between information in data and the parameters of an associated model.... This relationship can be formalised for the case of the continuous one-dimensional interaction model such as the population density model, and this paper is concerned with demonstrating such an application to aggregations of zones in the Reading [England] region."