The Effect of Gate-Bias Stress and Temperature on the Performance of ZnO Thin-Film Transistors

The stability of ZnO thin-film transistors is investigated by using gate-bias stress. It is found that the application of positive and negative stress results in the device transfer characteristics shifting in positive and negative directions, respectively. It is postulated that this device instability is a consequence of charge trapping at or near the channel/insulator interface. In addition, there is a degradation of subthreshold behavior and channel mobility, which is suggested to result from the defect-state creation within the ZnO layer. The effect of elevated temperature stress shows a predominance of interface-state creation in comparison to trapping under gate-bias stress. Device instability appears to be a consequence of the charging and discharging of preexisting trap states at the interface and in the channel region of the devices. All stressed devices recover their original characteristics after a short period at room temperature without the need for any thermal or bias annealing.     

Relationship of racial stressors to blood pressure responses and anger expression in Black college students.

27 Black college students viewed 3 excerpts showing racist situations involving Blacks; anger-provoking, nonracist situations; and neutral situations. After each scene, blood pressure (BP) was taken; a mood checklist, the Framingham Anger Scale (S. Haynes et al; see PA, Vol 68:10702), and the Anger Expression Scale of C. Spielberger et al (1985) were administered. Analyses revealed that BP significantly increased during the presentation of racist stimuli but not of anger-provoking or neutral stimuli. Self-reports of state anger, as measured by the mood checklist, were significant for both the anger-provoking and racist stimuli. BP scores were significantly correlated to the 2 trait anger measures. Exposure to racist stimuli was associated with BP increases among Blacks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Superconducting gap function and upper critical field in the presence of inhomogeneous magnetic order

Rare earth ternary superconductors are known to exhibit oscillatory magnetic orders below their superconducting transition temperatures. The study of behaviour of superconducting electrons in an inhomogeneous magnetic field is therefore important for such systems. We report here the results of our theoretical study of superconducting gap function Δ(T) and upper critical fieldH _c2 (T). The results are applied to analyse and explain the variation of Δ(T) andH _c2 (T) in case of NdRh₄B₄.     

Dietary exposure to copper in the European Union and its assessment for EU regulatory risk assessment

EU legislation requires a multimedia exposure assessment for substances supplied within the EU. Dietary intake is the main source of exposure for the majority of the population hence an essential component of the human risk assessment. This paper describes the available data for dietary copper and its use in estimating daily intake including variability and determinants of exposure. Typical and reasonable worst-case estimates are derived for the general population from the available peer reviewed literature. Intakes from drinking water are found to exhibit more variability than those from food. Therefore, different exposure scenarios are derived to reflect the range of acute and chronic exposures that may occur. Estimates of typical copper intakes for the EU population are in the range 0.8-1.8 mg/day. Typical copper intakes of men are higher than those of women while the intake among the general adult population is higher than that of the elderly. Intakes of both men and women are generally close to the WHO normative requirements but may be somewhat lower in specific locations where background levels of copper are unusually low. Alcoholic beverages represent minor contribution daily copper intakes. Intakes for children are rather variable ranging broadly from 0.7 to 1.5 mg/day and are somewhat age and sex dependent. Greater uncertainty applies to the assessment of local exposure incorporating food produced on land directly impacted by contemporary copper industry emissions. Specifically, the extent to which soil is enriched in copper in these conditions is unclear. However, effective homeostatic control mechanisms in plants limit uptake and transfer to the human food chain. A best estimate of 0.25 mg/day in addition to regional exposure was derived. Drinking water is estimated to contribute only marginally to total copper intake in most cases. Higher intakes may occur in areas of poor water quality and/or corroded distribution systems. Such elevated exposures appear unusual but their frequency is unknown.     

The uncertainty of radius estimation in least-squares sphere-fitting,with an introduction to a new summation based method

This paper considers the sensitivity of three sphere-fitting algorithms to real-world measurement errors. It pays particular attention to nominally spherical surfaces, such as those typically measured by tactile and optical profilometers, addressing the limitations of sensor gauge range and angular tolerance. A recently proposed linear circle-fitting algorithm is extended to a sphere-fitting algorithm and its performance compared to two long standing sphere-fitting algorithms; namely linear and non-linear least-squares. Sources of measurement error in optical profilometers are discussed, and user defined scan parameters are optimised based on the results of a designed experiment. The performance of all three sphere-fitting algorithms are tested on a sphere superimposed with varying degrees of surface irregularities in a Monte Carlo simulation; this study shows that both linear routines display a negative skewness in their radius error distribution. Finally, a method of predicting radius uncertainty is offered that considers the surface residual that remains after sphere-fitting and relates this to the radius uncertainty of the chosen algorithm.     

Update on Alzheimer''s disease

The nation's health care system is undergoing a period of rapid change that will profoundly affect women's health care services and, ultimately, women's health. Although managed care is quickly becoming the predominant mode of health care delivery in the United States, a new, more consumer-focused, and accountable model known as organized systems of care (OSC) is emerging. OSC development has been driven by large private and public employers seeking to purchase the highest quality health care for the best price. The changes in health care delivery encouraged by these innovative employers will provide women with optimal care and attention, which will in turn help them attract and retain a competitive and productive workforce.     

Continuous measurements of cardiac output in the perioperative period

Management of critically ill patients is based on knowledge of fundamental physiological variables. Automatized and continuous measurement of these variables is preferable. A new system based upon the thermodilution method has been developed to measure cardiac output automatically and continuously. We evaluated the system in the potentially unstable perioperative period with possible great and rapid changes in cardiac output. Twenty patients, scheduled for open heart or abdominal aortic aneurysm surgery, were included into the study, which was approved by the local ethical committee. The patients were monitored for up to 30 hours. At random intervals five iced bolus thermodilution cardiac output (BCO) determinations were made and compared to the continuous measurements (CCO). Two hundred and thirty-one pairs of data were obtained. The cardiac outputs ranged from 2.5-14.9 l/min. The absolute bias was 0.31 l/min (95% limits of agreement -1.4 l/min to 2.0 l/min). The mean relative error was 4.7% with a standard deviation of the relative error of 15.4%. The linear regression was represented by: CCO = 11.352 x BCO - 0.36. The correlation coefficient R was 0.90 (p < 0.001). In conclusion, the CCO measurement technique is a promising clinical method. The method is straightforward, requires no calibration, is independent of vascular geometry and measures with its limitations volumetric flow. Finally automatic and continuous patient monitoring provides more information and has potential to reveal previously undetected haemodynamic events.     

Toward a scalable, silicon-based quantum computing architecture

Advances in quantum devices have brought scalable quantum computation closer to reality. We focus on the system-level issues of how quantum devices can be brought together to form a scalable architecture. In particular, we examine promising silicon-based proposals. We discover that communication of quantum data is a critical resource in such proposals. We find that traditional techniques using quantum SWAP gates are exponentially expensive as distances increase and propose quantum teleportation as a means to communicate data over longer distances on a chip. Furthermore, we find that realistic quantum error-correction circuits use a recursive structure that benefits from using teleportation for long-distance communication. We identify a set of important architectural building blocks necessary for constructing scalable communication and computation. Finally, we explore an actual layout scheme for recursive error correction, and demonstrate the exponential growth in communication costs with levels of recursion, and that teleportation limits those costs.