Characteristics of GdGaO grown by MBE

Ga₂O₃/GdGaO dielectric stacks have been grown on GaAs for MOSFETs. This paper highlights variations in the characteristics of GdGaO as the Gd flux, Ga₂O flux and substrate temperature are changed. The growth rate, composition, crystallinity are discussed and the sheet resistance of final MOSFET structures are presented. The Gd compositional variation with depth is examined using Rutherford back scattering (RBS) and electron energy loss spectroscopy (EELS).     

Situvis: A sensor data analysis and abstraction tool for pervasive computing systems

Pervasive systems are large-scale systems consisting of many sensors capturing numerous types of information. As this data is highly voluminous and dimensional, data analysis tasks can be extremely cumbersome and time-consuming. Enabling computers to recognise real-world situations is an even more difficult problem, involving not only data analysis, but also consistency checking. Here we present Situvis, an interactive visualisation tool for representing sensor data and creating higher-level abstractions from the data. This paper builds on previous work, Clear et al. (2009) [8] through evolved tool functionality and an evaluation of Situvis. A user-trial consisting of 10 participants shows that Situvis can be used to complete the key tasks in the development process of situation specifications in over 50% less time than an improvised alternative toolset.     

AstroSim: Collaborative Visualization of an Astrophysics Simulation in Second Life

Developed in the Second Life 3D online multiuser environment, AstroSim (astrophysics simulation) provides synchronous collaborative visualization for astronomers. Users can play, halt, and rewind simulations and annotate stars interactively to track individual stars and gain a better understanding of stellar dynamics and astrophysics phenomena. This article is part of a special issue on collaborative visualization.     

An in vitro assay to evaluate competitive exclusion products for poultry

An in vitro assay was developed to measure the ability of competitive exclusion (CE) bacteria to protect Caco-2 and CRL-2117 epithelial cells from invasion by Salmonella Typhimurium. The proposed assay is needed to expedite the development of defined-flora CE products. The average significantly protective concentration of the commercial poultry-specific CE product Preempt was 4.05 log CFU/6.41 log human Caco-2 cells and 3.71 log CFU/6.89 log CFU chicken CRL-2117 cells, Enterococcus faecalis isolated from Preempt protected CRL-2117 cells, Escherichia coli isolates protected Caco-2 cells, Lactococcus lactis and Bacteroides distasonis isolates protected both cell lines, and three species of Lactobacillus isolates failed to protect either cell line. A defined mixture of 29 strains of bacteria similar to the constituents of Preempt protected both cell lines from Salmonella invasion at a concentration of 7.83 log CFU. The constituents of the defined CE culture were separated into mixtures of obligate (8.42 log CFU) and facultative (8.49 log CFU) anaerobes, which both protected the cell lines, suggesting that both types of bacteria were equally protective. Although not a substitute for in vivo testing, the in vitro CE assay is a rapid technique for the evaluation of bacterial mixtures for potential CE products.     

Helmet design to facilitate thermoneutrality during forest harvesting

The purpose of this investigation was to evaluate the ventilatory characteristics of vented and non-vented helmets for use in forestry harvesting operations. A ventilation index developed by Birnbaum and Crockford (1978) was used to determine the ventilation capacity of twelve helmets varying in design and presence, location, and dimension of vents. Helmets with top vents had higher ventilation indices than non-vented, side and side/top-vented helmets. Ten physically fit men participated in a maximal oxygen consumption test and four trials wearing a non-vented, round-side-vented, round-top-vented or rectangulartop-vented helmet. Trials simulated typical summer environmental conditions (28 degrees C, 80% rh) and physiological work loads (40% VO(2)max) experienced during forest harvesting in New Zealand. The temperature and humidity under the helmet was typically lowest when the helmet with the largest vented area (288 mm(2)) in the crown was worn, although physiological responses (temperatures at the tympanum, ear and scalp; humidity at the centre of the helmet) of the participants to wearing the helmets differed significantly during some rest periods only. Top-vented helmets (in this experiment measured 288 mm(2)) should be worn to minimize temperature and humidity of the head during forest harvesting operations.     

The influence of oxygen on the differentiation of temperature-sensitive and temperature-insensitive Lactococcus lactis subsp. cremoris starter strains

The differentiation of temperature-insensitive and temperature-sensitive strains of Lactococcus lactis subsp. cremoris by using a modified sodium-β-glycerophosphate/milk medium is described (temperature-insensitive strains are defined as those that continue to grow at 38°C and temperature-sensitive strains as those that do not grow, or grow poorly, at 38°C). The physiological basis for the differentiation assay was examined by using L. lactis subsp. cremoris strains 2146 (temperature-insensitive) and 2182 (temperature-sensitive) as test strains. After aerobic incubation on the medium, strain 2146 formed uniform colonies, 0·5 mm in diameter, while strain 2182 formed larger colonies, 1·0–1·5 mm in diameter. The differential was dependent on the medium constituents, on an aerobic gas phase, and on the effects of H₂O₂ generated within the colonies. The addition of 0·5% (w/v) pyruvate to the medium facilitated the growth of colonies of strain 2146 to 3-mm diameter, while the colony size of strain 2182 remained at 1-mm diameter, and thus the colony-size differential between strains was reversed. The growth of both strains was inhibited at 0·4–0·8% air saturation during suspension culture in sodium-β-glycerophosphate/milk medium. The inclusion of catalase in the cultures overcame the growth inhibition. There was no observable difference between the two strains in their oxygen sensitivity or NADH oxidase/peroxidase enzymology.     

The restricting effects of awareness: A paradox and explanation.

Ss were shown tachistoscopically-presented word stimuli to test the distinction between the perceptual processes of registration (what could be called physiological or sensory threshold) and awareness (or the cognitive threshold). The presentation consisted of a stimulus word followed by series of words associated to the stimulus word either in terms of meaning or structural resemblance. Recall of words presented subliminally or supraliminally was facilitated with degree of awareness of actual stimulus word; with greater awareness of the word, associational recall was for words that structurally resembled S word; without awareness, recall was determined by associative meaning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial coherence of backscatter for the nonlinearly produced second harmonic for specific transmit apodizations

To be successful, correlation-based, phase-aberration correction requires a high correlation among backscattered signals. For harmonic imaging, the spatial coherence of backscatter for the second harmonic component is different than the spatial coherence of backscatter for the fundamental component. The purpose of this work was to determine the effect of changing the transmit apodization on the spatial coherence of backscatter for the nonlinearly generated second harmonic. Our approach was to determine the effective apodizations for the fundamental and second harmonic using both experimental measurements and simulations. Two-dimensional measurements of the transverse cross sections of the finite-amplitude ultrasonic fields generated by rectangular and circular apertures were acquired with a hydrophone. Three different one-dimensional transmit apodization functions were investigated: uniform, Riesz, and trapezoidal. An effective apodization was obtained for each transmit apodization by backpropagating the values measured from within the transmit focal zone using a linear angular spectrum approach. Predictions of the spatial coherence of backscatter were obtained using the pulse-echo Van Cittert-Zernike theorem. In all cases the effective apodization at 2f was narrower than the transmit apodization. We demonstrate that certain transmit apodizations result in a greater spatial coherence of backscatter at the second harmonic than at the fundamental.