An Assessment of the Effects of Increased Regulatory Enforcement on Occupational Hearing Loss Workers' Compensation gon 1984-1998

Hearing loss from occupational exposures has been found to be a common and serious problem affecting workers. This paper examines the effect that increasing legislative enforcement of existing regulations has on improving worker safety.

Occupational Vehicular Accidents: A Workers' Compensation Analysis of Oregon Truck Drivers 1990-1997

This study used workers' compensation data from Oregon from 1990-1997 to examine injuries due to vehicular accidents by truck drivers, and calculate rate estimates using baseline data derived from the U.S. Bureau of Census' Current Population Survey. During this period, 1,168 valid injury claims due to vehicular accidents were filed representing an accident rate of 50.3% (95% C.I. = 45.1-55.5) per 10,000 truck drivers annually. There were 19 work-related vehicular accident fatalities recorded in the data over the 8-year period. Of all claimants, males constituted the majority (80.7%), most were 35 years of age or younger (51.4%) and had less than 1 year of job tenure (51.0%). Truck driver injury rates due to vehicular accidents were lowest during the 6:00 A.M. - 12:00 P.M. period. The average amount of compensable lost workdays per injury claim was 57.8 days, of which male claimants lost an average of 60.5 days of work and females lost an average of 46.9 days of work. The amount of lost work days due to vehicular accident increased with the claimant's age. A total of $11,642,635 was paid in claims for vehicular accidents of truck drivers in Oregon over the period examined, averaging$9,966.01 per claim. Sprains were the most frequently cited injury experienced from vehicular accidents.vehicular accidents, driving, truck drivers, workers' compensation, public health, workplace safety

Thermoregulation in rats: Effects of varying duration of hypergravic fields

The effects of hypergravitational fields on the thermoregulatory system of the rat are examined. The question underlying the investigation was whether the response of the rat to the one hour cold exposure depends only upon the amplitude of the hypergravic field during the period of cold exposure or whether the response is also dependent on the amplitude and duration of the hypergravic field prior to cold exposure. One hour of cold exposure applied over the last hour of either a 1, 4, 7, 13, 19, 25, or 37 hr period of 3G evoked a decrease in core temperature (T sub c) of about 3 C. However, when rats were subjected concurrently to cold and acceleration following 8 days at 3G, they exhibited a smaller fall in T sub c, suggesting partial recovery of the acceleration induced impairment of temperature regulation. In another series of experiments, the gravitational field profile was changed in amplitude in 3 different ways. Despite the different gravitational field profiles used prior to cold, the magnitude of the fall in T sub c over the 1 hr period of cold exposure was the same in all cases. These results suggest that the thermoregulatory impairment has a rapid onset, is a manifestation of an ongoing effect of hypergravity, and is not dependent upon the prior G profile

Effect of altered gravity on temperature regulation in mammals: Investigation of gravity effect on temperature regulation in mammals

Male, Long-Evans hooded rats were instrumented for monitoring core and hypothalamic temperatures as well as shivering and nonshivering thermogenesis in response to decreased ambient temperature in order to characterize the nature of the neural controller of temperature in rats at 1G and evaluate chronic implantation techniques for the monitoring of appropriate parameters at hypergravic fields. The thermoregulatory responses of cold-exposed rats at 2G were compared to those at 1G. A computer model was developed to simulate the thermoregulatory system in the rat. Observations at 1 and 2G were extended to acceleration fields of 1.5, 3.0 and 4.0G and the computer model was modified for application to altered gravity conditions. Changes in the acceleration field resulted in inadequate heat generation rather than increased heat loss. Acceleration appears to impair the ability of the neurocontroller to appropriately integrate input signals for body temperature maintenance

Disabling and Fatal Occupational Claim Rates, Risks, and Costs in the Oregon Construction Industry 1990-1997

Occupational research has demonstrated construction to be among the most dangerous of all occupational industries. This study examines 20,680 accepted workers' compensation claims filed by Oregon construction workers over the period of 1990-1997. Injury rate estimates for occupations were calculated using Oregon employment data from the Current Population Survey. The estimated annual rate of lost-time claims was 3.5 per 100 workers annually (95% CI=2.8-4.2) with insulators having the highest rate and supervisors the lowest. The majority of claims, 3,940, were filed by laborers. Over 52% of all claims were filed by workers under 35 years of age, and over half the claimants had less than 1 year of tenure at the time of injury. There were 52 fatalities reported, representing a rate of 8.5 per 100,000 workers (95% CI = 8.1-8.9), of which 32.7% resulted from falls. The most frequently recorded nature of non-fatal injury was listed as a "sprain," and the most common body part injured was the back. The total costs of all claims was $208,537,120, averaging$10,084 per claim, and the average indemnity time per injury was 57.3 days, with female claimants having longer indemnity periods than males. The highest percentage of claims by weekday occurred on Mondays (21.5%), and subsequent analysis showed the highest odds ratio for time of accident, relative to the first hour on the job, occurred on the third hour of work (OR = 2.456, 95% CI = 2.452-2.460.Construction; Workers' Compensation; Occupational Safety; Fatalities; Injuries; Musculoskeletal Disorders; Surveillance

Generalized Boltzmann Equation in a Manifestly Covariant Relativistic Statistical Mechanics

We consider the relativistic statistical mechanics of an ensemble of $N$ events with motion in space-time parametrized by an invariant ``historical time'' $\tau .$ We generalize the approach of Yang and Yao, based on the Wigner distribution functions and the Bogoliubov hypotheses, to find the approximate dynamical equation for the kinetic state of any nonequilibrium system to the relativistic case, and obtain a manifestly covariant Boltzmann-type equation which is a relativistic generalization of the Boltzmann-Uehling-Uhlenbeck (BUU) equation for indistinguishable particles. This equation is then used to prove the $H$-theorem for evolution in $\tau .$ In the equilibrium limit, the covariant forms of the standard statistical mechanical distributions are obtained. We introduce two-body interactions by means of the direct action potential $V(q),$ where $q$ is an invariant distance in the Minkowski space-time. The two-body correlations are taken to have the support in a relative $O( 2,1)$-invariant subregion of the full spacelike region. The expressions for the energy density and pressure are obtained and shown to have the same forms (in terms of an invariant distance parameter) as those of the nonrelativistic theory and to provide the correct nonrelativistic limit

Hypercomplex quantum mechanics

The fundamental axioms of the quantum theory do not explicitly identify the algebraic structure of the linear space for which orthogonal subspaces correspond to the propositions (equivalence classes of physical questions). The projective geometry of the weakly modular orthocomplemented lattice of propositions may be imbedded in a complex Hilbert space; this is the structure which has traditionally been used. This paper reviews some work which has been devoted to generalizing the target space of this imbedding to Hilbert modules of a more general type. In particular, detailed discussion is given of the simplest generalization of the complex Hilbert space, that of the quaternion Hilbert module.Comment: Plain Tex, 11 page

A Chiral Spin Theory in the Framework of an Invariant Evolution Parameter Formalism

We present a formulation for the construction of first order equations which describe particles with spin, in the context of a manifestly covariant relativistic theory governed by an invariant evolution parameter; one obtains a consistent quantized formalism dealing with off-shell particles with spin. Our basic requirement is that the second order equation in the theory is of the Schr\"{o}dinger-Stueckelberg type, which exhibits features of both the Klein-Gordon and Schr\"{o}dinger equations. This requirement restricts the structure of the first order equation, in particular, to a chiral form. One thus obtains, in a natural way, a theory of chiral form for massive particles, which may contain both left and right chiralities, or just one of them. We observe that by iterating the first order system, we are able to obtain second order forms containing the transverse and longitudinal momentum relative to a time-like vector $t_{\mu}t^{\mu}=-1$ used to maintain covariance of the theory. This time-like vector coincides with the one used by Horwitz, Piron, and Reuse to obtain an invariant positive definite space-time scalar product, which permits the construction of an induced representation for states of a particle with spin. We discuss the currents and continuity equations, and show that these equations of motion and their currents are closely related to the spin and convection parts of the Gordon decomposition of the Dirac current. The transverse and longitudinal aspects of the particle are complementary, and can be treated in a unified manner using a tensor product Hilbert space. Introducing the electromagnetic field we find an equation which gives rise to the correct gyromagnetic ratio, and is fully Hermitian under the proposed scalar product. Finally, we show that the original structure of Dirac'sComment: Latex, 61 pages. Minor revisions. To be published in J. Math. Phy

The faunal assemblage in freshwater crayfish burrows in sedgeland and forest at Lightning Plains, western Tasmania

The faunal assemblage of crayfish burrows was examined intensively at Lightning Plains in wesrern Tasmania, in sedgeland and adjacent forest, to determine variations in species occurrences and abundances both within one habitat type and between two habitats. Species -sample curves showed that over 90% of the species found in ten samples could be collected by taking only five. Despite the fact that the host crayfish species was the same, each habitat was found to display a characteristic assemblage. Variations between the assemblages are attributed to differences in soil conditions, vegetation structure and watertable behaviour

On the Green-Functions of the classical offshell electrodynamics under the manifestly covariant relativistic dynamics of Stueckelberg

In previous paper derivations of the Green function have been given for 5D off-shell electrodynamics in the framework of the manifestly covariant relativistic dynamics of Stueckelberg (with invariant evolution parameter $\tau$). In this paper, we reconcile these derivations resulting in different explicit forms, and relate our results to the conventional fundamental solutions of linear 5D wave equations published in the mathematical literature. We give physical arguments for the choice of the Green function retarded in the fifth variable $\tau$.Comment: 16 pages, 1 figur