Two posture analysis approaches and their application in a modified rapid upper limb assessment evaluation

This paper presents two posture risk quantification methods: first, an event-based method where the most common and the worst postures are estimated in a task; second, a time-based method where posture distributions are calculated from random samples of observed postures in the task. A 'click-on-screen' posture data entry method was developed for the time-based posture analysis method to make the observation process easier and to reduce possible posture categorization bias. Both methods were used to quantify various work posture parameters among a study cohort of 733 subjects from a prospective epidemiological study of upper extremity musculoskeletal disorders. Composite posture indices using a modified Rapid Upper Limb Assessment (RULA) method were also computed using data obtained by the two posture analysis methods. Results showed that both methods were able to distinguish jobs with large differences in certain posture measures. However, they did not produce the same results and could not be used interchangeably. Risk evaluation criteria should be developed, either for specific posture parameters or as a composite index, with a well-defined postural analysis method, so that users can follow exact procedures and obtain comparable results. The event-based method is easy to use and may suit practitioners better, while the time-based method adds more information to the measurement and may suit users who want more detailed information about posture exposure.     

Flexible Image-Based Photometric Reconstruction using Virtual Light Sources

Photometric reconstruction is the process of estimating the illumination and surface reflectance properties of an environment, given a geometric model of the scene and a set of photographs of its surfaces. For mixed-reality applications, such data is required if synthetic objects are to be correctly illuminated or if synthetic light sources are to be used to re-light the scene. Current methods of estimating such data are limited in the practical situations in which they can be applied, due to the fact that the geometric and radiometric models of the scene which are provided by the user must be complete, and that the position (and in some cases, intensity) of the light sources must also be specified a-priori. In this paper, a novel algorithm is presented which overcomes these constraints, and allows photometric data to be reconstructed in less restricted situations. This is achieved through the use of virtual light sources which mimic the effect of direct illumination from unknown luminaires, and indirect illumination reflected off unknown geometry. The intensity of these virtual light sources and the surface material properties are estimated using an iterative algorithm which attempts to match calculated radiance values to those observed in photographs. Results are presented for both synthetic and real scenes that show the quality of the reconstructed data and its use in off-line mixed-reality applications.     

Free radicals in γ-irradiated PETN

An EPR investigation of-irradiated PETN (Pentaerythritol Tetranitrate) was conducted. Low temperature irradiation accumulates at least two different radicals. The more stable radical is the NO₂ radical presumably produced by photon cleavage of the NO₂ groups and/or by radical reactions in excited states resulting in detached NO₂. The spectrum of the more reactive radical is obtained by computer substraction. Decay kinetics are proposed for the NO₂ and the unknown highly reactive radical.     

Groundwater temperature and degassing in the Mad River subwatershed of Lake Huron

Groundwater was measured 70 times in two years at 10 sites as it flowed 50 m over an accumulation of travertine (CaCO₃) before reaching the Mad River. At source, the groundwater was relatively cool (6.77 ± 2.89 °C), slightly acidic ( pH 6.86 ± 0.22), and had a moderately high specific conductivity (606 ± 51 μS). Degassing was assessed from increases in pH, and CaCO₃ deposition was assessed from decreasing conductivity. After flowing over the experimental site, degassing had increased pH to 8.04 ± 0.16 (P < 0.001), which was similar to river water (pH 8.07 ± 0.30). Concurrently, CaCO₃ deposition decreased conductivity to 577 ± 43 μS (P < 0.001) but this was still higher (P < 0.001) than river water (494 ± 72). Seasonal changes in air temperature affected the rate of degassing. The pH was correlated with air temperature (r = 0.15, P < 0.001) while conductivity was correlated with pH (r = − 0.27, P < 0.001), but no direct relationship of air temperature with conductivity was detected. Groundwater entering the river after atmospheric exposure had a fairly constant temperature (7.05 ± 1.22 °C) despite seasonal changes in air temperature, thus warming the river in winter (up to day 100 and after day 300) and cooling it in summer (from days 140 to 260). Degassing and CaCO₃ deposition in springs without travertine was similar to that observed in the study stream over travertine. These groundwater inflows provide favorable pH and temperature conditions for brook trout.     

Probabilistic resource allocation in heterogeneous distributed systems with random failures

The problem of finding efficient workload distribution techniques is becoming increasingly important today for heterogeneous distributed systems where the availability of compute nodes may change spontaneously over time. Resource-allocation policies designed for such systems should maximize the performance and, at the same time, be robust against failure and recovery of compute nodes. Such a policy, based on the concepts of the Derman–Lieberman–Ross theorem, is proposed in this work, and is applied to a simulated model of a dedicated system composed of a set of heterogeneous image processing servers. Assuming that each image results in a “reward” if its processing is completed before a certain deadline, the goal for the resource allocation policy is to maximize the expected cumulative reward. An extensive analysis was done to study the performance of the proposed policy and compare it with the performance of some existing policies adapted to this environment. Our experiments conducted for various types of task-machine heterogeneity illustrate the potential of our method for solving resource allocation problems in a broad spectrum of distributed systems that experience high failure rates.     

Trail-following pheromones of the rhinotermitidae: Approaches to their authentication and specificity

A method for determining the authenticity of subterranean termite trail pheromones is suggested and utilized to verify the presence of trail pheromones inReticulitermes virginicus, R. flavipes, andR. tibialis. In addition, a possible trail pheromone has been demonstrated forCoptotermes formosanus. A choice bioassay method shows that the above trail pheromones are species specific.     

Effect of gate poly-silicon depletion on MOSFET input impedance

One of the most challenging problems encountered in developing RF circuits is accurate prediction of MOS behavior at microwave signal and data frequencies. An attempt is made in this work to accurately model the device input impedance for the 1-20-GHz frequency range. The effect of device length and single-leg width on the input impedance is studied with the aid of extensive measured data obtained from devices built in 0.11-/spl mu/m and 0.18-/spl mu/m technologies. The measured data illustrates that the device input impedance has a nonlinear frequency dependency. It is also shown that this variation in input impedance is a result of gate poly-silicon depletion, which can be modeled by an external RC network connected at the gate of the device. Excellent agreement between the simulation results and the measured data validates the model in the device active region.     

Psychology and Phenomenology: A Clarification.

Controversies are rampant in contemporary psychology concerning the appropriate method for observing consciousness and the role inner experience should play in psychological theorizing. These conflicting orientations reflect, in part, methodological differences between natural science and human science interpretations of psychology. Humanistic psychology and philosophical phenomenology both employ a human science approach to psychology that seeks to explain behavior in terms of a person's subjective existence. Maslow's and Heidegger's formulations are both fulfillment theories in that they specify moral values that suggest how life ought to be lived. Natural science methodology rejects the possibility that moral imperatives can be validated, whereas human science methodology allows phenomenological convictions to justify recommendations about a fulfilled life and a good society. The social role of psychology is analyzed within the framework of phenomenological convictions and scientific truth. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trends in ecstasy use in the United States from 1995 to 2001: Comparison with marijuana users and association with other drug use.

This study aims to estimate changes in the prevalence of ecstasy use over time, analyze the overlap of ecstasy use and other drug use, and compare other drug use in ecstasy versus marijuana users. The authors hypothesized that ecstasy users early in the "epidemic" would be polydrug users and that associations between ecstasy and other drug use would diminish as the prevalence of ecstasy use increased. Data were drawn from public use data files from the 1995, 1997, 1999, and 2001 National Household Survey on Drug Abuse. Ecstasy use increased in the U.S. population and the prevalence was greater in younger age groups. Ecstasy users were likely to use a variety of other drugs; however, association of ecstasy use with other drug use was strongest early in the "epidemic," diminishing as the number of new users increased. Later, more drug-naive adolescents and young adults began experimenting with ecstasy. These results can orient prevention strategies that target ecstasy users. (PsycINFO Database Record (c) 2010 APA, all rights reserved)