Optimal filtering of constant velocity torque data.

The purpose of this investigation was to implement an optimal filtering strategy for processing in vivo dynamometric data. The validity of employing commonly accepted analog smoothing methods was also appraised. An inert gravitational model was used to assess the filtering requirements of two Cybex II constant velocity dynamometers at 10 pre-set speeds with three selected loads. Speed settings were recorded as percentages of the servomechanism's maximum tachometer feedback voltage (10 to 100% Vfb max). Spectral analyses of unsmoothed torque and associated angular displacement curves, followed by optimized low-pass digital filtering, revealed the presence of two superimposed contaminating influences: a damped oscillation, representing successive sudden braking and releasing of the servomechanism control system; a relatively stationary oscillatory series, which was attributed to the Cybex motor. The optimal cutoff frequency for any data set was principally a positive function of % Vfb max. This association was represented for each machine by a different, but reliable, third order least-squares polynomial, which could be used to accurately predict the correct smoothing required for any speed setting. Unacceptable errors may be induced, especially when measuring peak torques, if data are inappropriately filtered. Over-smoothing disguises inertial artefacts. The use of Cybex recorder damping settings should be discouraged. Optimal filtering is a minimal requirement of valid data processing.

Constant velocity dynamometer: an appraisal using mechanical loading.

Measurement characteristics of two constant velocity dynamometers (Cybex II, Lumex, Inc., NY) were evaluated at 11 selected speeds (0 to 5 rad X s-1) under various conditions of inert gravitational loading. A linear accelerometer was affixed to the lever arm. Speed settings were standardized percentages of each machine's maximum tachometer feedback voltage (0 to 100% Vfb max). Regression of Cybex transducer-observed voltages (V0) on true, i.e., expected, torques (Me) revealed that, for any static loading condition or angle, the measurement system was essentially linear and valid, although greater variance was evident for smaller torques. However, different calibrations, i.e., regression lines, were required for different speed settings. The error in predicting Me from V0 increased substantially with increased % Vfb max. Methodologies which assume constant velocity dynamic loading induce questionable, often invalid, results and inferences. Dynamic V0 represents both gravitational and inertial components. Considerable fluctuations in lever arm instantaneous velocity were ascribed to the combined influence of load and % Vfb max upon the servomotor. After computing inertia-corrected Me, calibration variability and prediction error were markedly reduced. Unexplained variability may be due to poor proximity of the Cybex transducer to the force application point. We concluded that: Cybex II should be calibrated only statically; use of an optimal filter will avoid false estimates of joint torque; inertial corrections must be applied in order to minimize potentially serious errors due to system angular acceleration; and reported muscle function relationships might be usefully re-assessed in view of these findings.

A comparison of African American and White American veteran MMPI-2 profiles.

The present study compared a matched sample of 180 African American and 180 White American veterans who completed the MMPI-2 as a part of their evaluation while receiving inpatient psychiatric treatment. Findings indicated no significant multivariate or univariate effects associated with race on the basic validity and clinical scales, a significant multivariate effect but no significant univariate effects associated with race across the supplementary scales. Overall the two groups had very similar mean profiles across the basic validity, clinical, and supplementary scales. Comparison of the two groups on the content scales yielded a significant multivariate and significant univariate effects with African Americans scoring higher on the FRS, BIZ, CYN, and ASP scales. Because the two groups differed in terms of frequency and type of drug abuse, follow-up 2 x 2 univariate analyses of variance were conducted for the FRS, BIZ, CYN, and ASP content scales comparing participants classified in terms of presence or absence of a primary or secondary drug abuse diagnosis by race. A significant main effect associated with drug abuse was obtained for ASP. Results are discussed and considered in light of earlier research on the MMPI-2 and race. Content scale differences are also discussed in terms of possible differences in worldview.

Impacts of domestic population dynamics and foreign wood trade on deforestation: a world-system perspective.

PIP: World system theory posits that core nations control global production processes through their economic and political-military strength, while countries at the periphery remain technologically underdeveloped and operate from a position of dependency. Rapid changes such as population growth and rural encroachment have spurred environmental degradation in the intermediary semi-periphery countries. The effects of world system structure on national deforestation were investigated in a quantitative, cross-national analysis of data from 60 core, semi-peripheral, and peripheral countries. This analysis revealed that rural population growth has had a deleterious effect on forestation throughout the world system. However, the impact of general population growth has been negative only in non-core countries. As hypothesized, forest exports have resulted in ecologic devastation in the periphery of the world system, but have exerted a favorable effect for core countries where reforestation programs dominate. These findings suggest that population growth per se is not the critical factor in environmental degradation. Urged are further quantitative evaluations of the environmental impact of other international commodity trades.^ieng

Determination of trace volatile organic compounds in fish tissues by gas chromatography.

Several volatile organic compounds associated with petroleum fuels (mainly alkylated benzenes) were extracted from spiked fish tissue samples with a stream of air, trapped on charcoal, eluted with a solvent, and analyzed by gas chromatography. These volatile compounds are among the most water-soluble components of crude oils and petroleum products, and they have been associated with tainting in fish tissues. Recoveries for these compounds were about 90% when spiked directly either onto traps or into fish tissues although naphthalene desorbed poorly from the charcoal; recoveries of this compound were about 50%. Relative standard deviations (RSD) for most recoveries of spiked samples were in the 2-10% range based on 6 samples analyzed in duplicate. However, when live fish were contaminated experimentally by adding the aromatic compounds to the aquarium water, the RSDs were higher (10-30%).

Microextraction and gas chromatographic analysis of selected petroleum hydrocarbons in water and fish tissue.

The most effective water to solvent ratio is determined for the analyses of aromatic hydrocarbons in water using hexane. The recoveries of these hydrocarbons formed in the water soluble fraction of crude oils and petroleum products are measured using a microextraction procedure. Recoveries were in the 30-40% range but are consistent for each compound. Fish muscle samples are fortified with the standards and the recoveries measured with a modified extraction procedure using dichloromethane as the primary extracting solvent. This is dispersed in water using acetone and finally extracted with hexane. Recoveries range from 90-113% with a mean value of 98%.

Lipopolysaccharide from the periodontal pathogen Porphyromonas gingivalis prevents apoptosis of HL60-derived neutrophils in vitro.

Lipopolysaccharide (LPS) from Porphyromonas gingivalis prevented apoptosis of HL60-derived neutrophils, which could not be restored upon the addition of interleukin-10. Signaling of P. gingivalis LPS through Toll-like receptor 2 (TLR2), not TLR4, may account for the inhibiting effect of P. gingivalis LPS on apoptosis and provide a mechanism for the development of destructive periodontal inflammation.

Sex pheromone of cranberry fruitworm,Acrobasis vaccinii riley (Lepidoptera: Pyralidae).

The following compounds and (approximate ratios) were identified in sex pheromone gland extracts of femaleAcrobasis vaccinii Riley by comparison of gas chromatography-mass spectrometric traces with those of synthetic standards: (E,Z)-, (Z,E)-, (Z,Z), and (E,E)-8, 10-pentadecadien-l-ol acetates (100:1:2:12), a dodecen-l-ol acetate (8), (Z)-8-, (Z)-9-, and (E)-9-pentadecen-l-ol acetates (3:23:4), two heptadecen-l-ol acetates (4:4), tetradecyl, pentadecyl, hexadecyl, and heptadecyl acetates (3:15:10:8), dodecan-l-ol (6), tetradecan-l-ol (5), and hexadecan-l-ol (23). The amount of (E,Z)-8, 10-pentadecadien-l-ol acetate (E8,Z10-15:Ac) in the extract was about 0.5 ng/female. Electroantennographic analysis of gas chromatographic fractions of female sex pheromone gland extract showed that the fraction containingE8,Z10-15:Ac elicited the greatest response. Alone,E8,Z10-15:Ac failed to elicit upwind flight of males in flight-tunnel tests, and traps baited with it did not catch males in field experiments. WhenE8,Z10-15:Ac was combined with (E)-9-pentadecen-l-ol acetate (100:4), male upwind flight response in flight-tunnel tests was equivalent to those obtained with extract of female sex pheromone glands (synthetic, 62%; natural, 51%), but the percent of males flying upwind that contacted the source was lower (synthetic, 47%; natural, 88%). The lower percent of source contact elicited by the synthetic pheromone could be a result of the difference in isomer ratios of 8,10-15:Ac in the natural and synthetic pheromone or could indicate that the synthetic pheromone is incomplete. Traps baited with the 100:4 combination caught large numbers of males in field experiments.