Digital control of diode laser for atmospheric spectroscopy

A system is described for remote absorption spectroscopy of trace species using a diode laser tunable over a useful spectral region of 50 to 200 cm(-1) by control of diode laser temperature over range from 15 K to 100 K, and tunable over a smaller region of typically 0.1 to 10 cm(-1) by control of the diode laser current over a range from 0 to 2 amps. Diode laser temperature and current set points are transmitted to the instrument in digital form and stored in memory for retrieval under control of a microprocessor during measurements. The laser diode current is determined by a digital to analog converter through a field effect transistor for a high degree of ambient temperature stability, while the laser diode temperature is determined by set points entered into a digital to analog converter under control of the microprocessor. Temperature of the laser diode is sensed by a sensor diode to provide negative feedback to the temperature control circuit that responds to the temperature control digital to analog converter

Wave techniques for noise modeling and measurement

The noise wave approach is applied to analysis, modeling, and measurement applications. Methods are presented for the calculation of component and network noise wave correlation matrices. Embedding calculations, relations to two-port figures-of-merit, and transformations to traditional representations are discussed. Simple expressions are derived for MESFET and HEMT noise wave parameters based on a linear equivalent circuit. A noise wave measurement technique is presented and experimentally compared with the conventional method

OSHA Regulation of Benzene: The Missing Ingredient of Cost-Benefit Analysis

The 1980 Supreme Court ruling on the regulation of benzene in the workplace sidestepped the troubling question of the role cost-benefit analysis should play in Occupational Safety and Health Administration (OSHA) regulation of toxic substances. Cost-benefit analysis consists of an agency estimate of expected health benefits from a proposed standard, an estimate of what it will cost the affected industry to comply with the standard, and a determination of whether the expected benefits bear a reasonable relationship to the estimated costs. In evading the issue of whether or not the OSH Act requires the agency to undertake a cost-benefit analysis prior to promulgation of standards, the plurality opinion in Industrial Union Department, AFL-CIO v. American Petroleum Institute left open a question which has perplexed workers, industry, the agency and courts for a decade. It appears likely, however, that the opinion on benzene regulation only postponed a Supreme Court examination of the issue. Cost-benefit analysis and its significance to OSHA regulation of toxic substances in the workplace may have an appreciably greater impact in the near future as the Supreme Court is expected to rule on the OSHA cotton dust standard this term. This comment will examine the benzene issue and how cost-benefit analysis might relate to its control as seen by OSHA, the United States Court of Appeals for the Fifth Circuit, and Justice Powell. The comment will also explore the OSH Act, pertinent legislative history and current judicial interpretation of that history because the key question is whether the Act requires OSHA to undertake cost-benefit analysis. The decisions of lower federal courts on OSHA’s regulatory control of other toxic substances will also be examined

Multiresolution analysis in statistical mechanics. II. The wavelet transform as a basis for Monte Carlo simulations on lattices

In this paper, we extend our analysis of lattice systems using the wavelet transform to systems for which exact enumeration is impractical. For such systems, we illustrate a wavelet-accelerated Monte Carlo (WAMC) algorithm, which hierarchically coarse-grains a lattice model by computing the probability distribution for successively larger block spins. We demonstrate that although the method perturbs the system by changing its Hamiltonian and by allowing block spins to take on values not permitted for individual spins, the results obtained agree with the analytical results in the preceding paper, and ``converge'' to exact results obtained in the absence of coarse-graining. Additionally, we show that the decorrelation time for the WAMC is no worse than that of Metropolis Monte Carlo (MMC), and that scaling laws can be constructed from data performed in several short simulations to estimate the results that would be obtained from the original simulation. Although the algorithm is not asymptotically faster than traditional MMC, because of its hierarchical design, the new algorithm executes several orders of magnitude faster than a full simulation of the original problem. Consequently, the new method allows for rapid analysis of a phase diagram, allowing computational time to be focused on regions near phase transitions.Comment: 11 pages plus 7 figures in PNG format (downloadable separately

COMPARING MANAGEMENT SYSTEMS FOR BEEF CATTLE BACKGROUNDING: A MULTIDISCIPLINARY APPROACH

Livestock Production/Industries,

Thermal emission from low-field neutron stars

We present a new grid of LTE model atmospheres for weakly magnetic (B<=10e10G) neutron stars, using opacity and equation of state data from the OPAL project and employing a fully frequency- and angle-dependent radiation transfer. We discuss the differences from earlier models, including a comparison with a detailed NLTE calculation. We suggest heating of the outer layers of the neutron star atmosphere as an explanation for the featureless X-ray spectra of RX J1856.5-3754 and RX J0720.4-3125 recently observed with Chandra and XMM.Comment: 8 pages A&A(5)-Latex, 6 Figures, A&A in press. The model spectra presented here are available as XSPEC tables at http://www.astro.soton.ac.uk/~btg/outgoing/nsspec

The Effects Of Individual Differences And Industry Stability On Auditors' Perceived Risk Assessments

The U. S. Public Oversight Board’s Panel on Audit Effectiveness suggests that both audit effectiveness and efficiency may benefit from greater consideration being given to auditors’ risk assessments. The association between several independent variables (e.g., tolerance-for-ambiguity, field dependence/independence, and industry stability) and auditors’ perceived risk assessments is examined in an experimental setting. Six hypotheses suggested from a review of the literature are tested. The results indicate that industry stability and (to a lesser extent) tolerance-for-ambiguity (TFA) each have a main effect on auditors’ perceived risk assessments. Further, these two variables are found to have a moderately significant interactive effect on such assessments. The level of industry stability (stable or unstable) is found to affect the risk assessments of low-TFA subjects more than high-TFA subjects. Implications of these results for the audit process are provided