TEM study of the recovery process of cyclically deformed MgO single crystals

Single crystals of MgO were subjected to plastic strain-controlled push-pull cyclic deformation at elevated temperatures. Below 400° C the crystals were very brittle and failed with a few fatigue cycles. At 470° C a large number of cycles could be obtained before failure, and the cyclic stress-strain response showed a period of rapid hardening followed by a period of decreasing hardening rate. TEM investigations of the lower temperature samples show structures of isolated dislocation dipoles, multipoles and debris. At 470° C dense bundles of dislocations were observed aligned perpendicular to the Burgers vector direction. The regions between the bundles were relatively dislocation free, but they contained a high density of debris. Bowed out screw dislocations are observed between the edge dislocation bundles, suggesting that screw dislocations were largely mobile. Comparisons are made with the cyclic deformation and structure of fcc metals and other NaCl structure single crystals.     

Effect of intrinsic phase mismatch on linear modulator performanceof the 1×2 directional coupler and Mach-Zehnderinterferometer

The performance of 1×2 directional couplers and Mach-Zehnder interferometers as linear modulators is compared. Models describing the operation of each device, incorporating the intrinsic phase mismatch Δβ₀ which is present in nonideal devices, are developed. Distributions of Δβ₀ are obtained for each device and are shown to be independent of device type. Linear dynamic range and sensitivity measurements showing how Δβ₀ affects performance agree with theory. The additional effect of the coupling coefficient in the 1×2 directional coupler is demonstrated. This information can be used to predict device yield when combined with the measured Δβ₀ distributions     

Anger management style and emotional reactivity to noxious stimuli among chronic pain patients and healthy controls: The role of endogenous opioids.

Objective: Previous work suggests that elevated trait anger-out exacerbates pain responses in part through endogenous opioid dysfunction. The authors examined whether this opioid dysfunction affects not only perceived pain intensity, but also emotional responses to being hurt. Design: 79 chronic low back pain (LBP) patients and 46 healthy controls received opioid blockade (8 mg naloxone i.v.) and placebo in randomized, counterbalanced order in separate sessions. During each session, participants sequentially experienced finger pressure pain and ischemic forearm pain tasks, with emotional state assessed at baseline and postpain. Main Outcome Measures: Blockade effects indexing opioid modulation of emotional reactivity were derived by subtracting placebo from blockade condition emotional reactivity. Results: Significant Participant Type × Anger-Out interactions on blockade effects indicated that in LBP participants but not in controls, greater anger-out was associated with deficient opioid modulation of anxiety, anger, and fear reactivity to noxious stimulation. Across participant types, greater anger-in was associated with impaired opioid modulation of anxiety and fear reactivity. Anger-in opioid effects were partially due to overlap with general negative affect. Conclusions: Opioid dysfunction associated with trait anger-out may affect not only perceived pain intensity, but also pain-related suffering in individuals with chronic pain conditions. Implications for understanding the health effects of anger management styles are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of non-Newtonian liquids using a microfluidic capillary viscometer

We have used a self-calibrating microfabricated capillary viscometer to analyze non-Newtonian power law fluids. The capillary viscometer can generate a wide range of shear rates during a single experimental run enabling quick and accurate analysis of non-Newtonian liquids. The measurement of viscosity is based on monitoring the capillary pressure-driven movement of fluid sample whose mean velocity and, therefore, shear rate varies with time. The device has been successfully tested for accuracy and robustness with dilute as well as semidilute solutions of flexible elastic polymers including poly(ethylene oxide) and hydrolyzed polyacrylamide to an aqueous solution of a stiff rodlike polymer molecule of xanthan gum, a popular emulsifier and food thickener, as well as with ink-jet printing inks. Viscosities in the range of 1-600 cP were measured, and shear rates varying from 5 to 1000 s(-1) have been obtained on the microfabricated viscometer with the current geometry and channel dimensions. The total measurement time varied between 2 and 8 min and less than 1 microL of sample volume was required. Such a microfabricated capillary viscometer would have possible applications in quality control and manufacturing where rapid and repeated measurements need to be made using limited sample volume.     

Predicting sales performance, job satisfaction, and depression by using the Achievement Strivings and Impatience-Irritability dimensions of Type A behavior.

Recent research suggested that two dimensions of Type A behavior, namely, Achievement Strivings (AS) and Impatience-Irritability (II), differentially predict physical health and performance outcomes. The present study extends this research and examines whether AS and II differentially predict work performance (number of insurance policies sold), work attitudes (job satisfaction), and depression in a sample of 117 life insurance salespersons. As hypothesized, after statistically controlling for relevant biographical variables and II, AS predicted the number of policies sold and job satisfaction but was not related to depression. After partialing out the effect of relevant biographical variables and AS, II was associated with depression but not with the number of policies sold. In addition, controlling for the same variables, II was negatively associated with job satisfaction. Implications for the prediction of sales performance, job satisfaction, and depression, and interventions designed to decrease the negative consequences of Type A by reducing II but not AS, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Managing the risks of artificial general intelligence: A human factors and ergonomics perspective

Artificial General Intelligence (AGI) is the next and forthcoming evolution of Artificial Intelligence (AI). Though there could be significant benefits to society, there are also concerns that AGI could pose an existential threat. The critical role of Human Factors and Ergonomics (HFE) in the design of safe, ethical, and usable AGI has been emphasized; however, there is little evidence to suggest that HFE is currently influencing development programs. Further, given the broad spectrum of HFE application areas, it is not clear what activities are required to fulfill this role. This article presents the perspectives of 10 researchers working in AI safety on the potential risks associated with AGI, the HFE concepts that require consideration during AGI design, and the activities required for HFE to fulfill its critical role in what could be humanity's final invention. Though a diverse set of perspectives is presented, there is broad agreement that AGI potentially poses an existential threat, and that many HFE concepts should be considered during AGI design and operation. A range of critical activities are proposed, including collaboration with AGI developers, dissemination of HFE work in other relevant disciplines, the embedment of HFE throughout the AGI lifecycle, and the application of systems HFE methods to help identify and manage risks.     

Spatial and seasonal variability of dissolved methylmercury in two stream basins in the eastern United States

We assessed methylmercury (MeHg) concentrations across multiple ecological scales in the Edisto (South Carolina) and Upper Hudson (New York) River basins. Out-of-channel wetland/floodplain environments were primary sources of filtered MeHg (F-MeHg) to the stream habitat in both systems. Shallow, open-water areas in both basins exhibited low F-MeHg concentrations and decreasing F-MeHg mass flux. Downstream increases in out-of-channel wetlands/floodplains and the absence of impoundments result in high MeHg throughout the Edisto. Despite substantial wetlands coverage and elevated F-MeHg concentrations at the headwater margins, numerous impoundments on primary stream channels favor spatial variability and lower F-MeHg concentrations in the Upper Hudson. The results indicated that, even in geographically, climatically, and ecologically diverse streams, production in wetland/floodplain areas, hydrologic transport to the stream aquatic environment, and conservative/nonconservative attenuation processes in open water areas are fundamental controls on dissolved MeHg concentrations and, by extension, MeHg availability for potential biotic uptake.     

WCET Analysis of Superscalar Processors Using Simulation With Coloured Petri Nets

Determining a tight WCET of a block of code to be executed on a modern superscalar processor architecture is becoming ever more difficult due to the dynamic behaviour exhibited by current processors, which include dynamic scheduling features such as speculative and out-of-order execution in the context of multiple execution units with deep pipelines. We describe the use of Coloured Petri Nets (CP-nets) in a simulation based approach to this problem. A complex model of a generic processor architecture is described, with emphasis on the modelling strategy for obtaining the WCET and an analysis of the results.