8,898 research outputs found
A relativistically covariant version of Bohm's quantum field theory for the scalar field
We give a relativistically covariant, wave-functional formulation of Bohm's
quantum field theory for the scalar field based on a general foliation of
space-time by space-like hypersurfaces. The wave functional, which guides the
evolution of the field, is space-time-foliation independent but the field
itself is not. Hence, in order to have a theory in which the field may be
considered a beable, some extra rule must be given to determine the foliation.
We suggest one such rule based on the eigen vectors of the energy-momentum
tensor of the field itself.Comment: 1 figure. Submitted to J Phys A. 20/05/04 replacement has additional
references and a few minor changes made for clarity. Accepted by J Phys
A non-local, Lorentz-invariant, hidden-variable interpretation of relativistic quantum mechanics based on particle trajectories
We demonstrate how to construct a lorentz-invariant, hidden-variable
interpretation of relativistic quantum mechanics based on particle
trajectories. The covariant theory that we propose employs a multi-time
formalism and a lorentz-invariant rule for the coordination of the space-time
points on the individual particle trajectories. In this way we show that there
is no contradiction between nonlocality and lorentz invariance in quantum
mechanics. The approach is illustrated for relativistic bosons, using a simple
model to discuss the individual non-locally correlated particle motion which
ensues when the wavefunction is entangled. A simple example of measurement is
described.Comment: 12 pages, 2 figure
Soil moisture and evapotranspiration predictions using Skylab data
The author has identified the following significant results. Multispectral reflectance and emittance data from the Skylab workshop were evaluated for prediction of evapotranspiration and soil moisture for an irrigated region of southern Texas. Wavelengths greater than 2.1 microns were required to spectrally distinguish between wet and dry fallow surfaces. Thermal data provided a better estimate of soil moisture than did data from the reflective bands. Thermal data were dependent on soil moisture but not on the type of agricultural land use. The emittance map, when used in conjunction with existing models, did provide an estimate of evapotranspiration rates. Surveys of areas of high soil moisture can be accomplished with space altitude thermal data. Thermal data will provide a reliable input into irrigation scheduling
Crop Residue Effects on Surface Radiation and Energy Balance - Review
Crop residues alter the surface properties of soils. Both shortwave albedo and longwave emissivity are affected. These are linked to an effect of residue on surface evaporation and water content. Water content influences soil physical properties and surface energy partitioning. In summary, crop residue acts to soil as clothing acts to skin. Compared to bare soil, crop residues can reduce extremes of heat and mass fluxes at the soil surface. Managing crop residues can result in more favorable agronomic soil conditions. This paper reviews research results of the quantity, quality, architecture, and surface distribution of crop residues on soil surface radiation and energy balances, soil water content, and soil temperature
Haematological and blood chemistry changes in ewes and lambs following supplementation with vitamin E and selenium
1. Four methods of vitamin E and selenium supplementation were evaluated using thirty-nine pregnant ewe-lambs fed on a ration containing 0.043 mg Se/kg and 25 mg vitamin E/kg. Treatments were control, fortified mineral mix (ESe salt) (300 mg vitamin E, 3 mg Se), ruminal Se pellets (505 mg Se), drench (300 mg vitamin E, 3 mg Se) and intramuscular injection (600 mg vitamin E, 3 mg Se). Only ewes were supplemented, commencing approximately 50 d before parturition. 2. Birth weights were similar for all treatments and live-weight gains of lambs to 56 d of age were improved in all supplemented groups (P < 0.05). There were no clinical cases of nutritional muscular dystrophy. 3. Se concentrations in whole blood were more than doubled in both lambs and ewes drenched or injected; responses to ESe salt and pellets were much smaller. 4. Plasma tocopherol levels were increased in injected dams and their lambs (P < 0.001). 5. Haemoglobin concentration and erythrocyte counts were significantly higher (P < 0.01) in control ewes and lambs than in treated lambs. 6. Lactate dehydrogenase (EC 1.1.1.27), creatine kinase (EC 2.7.3.2) and aspartate aminotransferase (EC 2.6.1.1) activities were increased in lambs from control, ESe salt and pellet groups (P < 0.001). Glutathione peroxidase (EC 1.1.1.1.9) activity responded to Se supplementation in both ewes and their lambs (P < 0.001) and the response was highest in the injected group, followed, in order, by the drench, pellet, ESe salt and control groups. 7. These studies indicated that in terms of the haematological and blood chemistry changes investigated, the intramuscular injection was most effective, followed by the oral drench. Ruminal pellets and fortified salt were less satisfactor
High temporal and spatial resolution reflectometry investigations of type-I ELMs induced edge barrier collapse at ASDEX Upgrade
Engaged Trauma Training Through Role-Play Observations during COVID-19
This phenomenological investigation explored counselors\u27-in-training experiences while observing role-plays of trauma-specific cases. Three themes emerged: (a) learning to be a trauma counselor, (b) growth as counselors-in-training, and (c) connection and engagement through multiple delivery methods. The findings from this study showed that observing role-plays can be an efficacious teaching approach in trauma counseling courses. Findings also suggest that integrating role-plays into trauma curricula helped students understand the complexity of trauma, increase self-competency, self-efficacy, and emotional intelligence, and engage with the content in face-to-face and online formats. The authors provide a further discussion on implications for counselor education and research
Systematic Review and Meta-Analysis of Sex Differences in Social Contact Patterns and Implications for Tuberculosis Transmission and Control.
Social contact patterns might contribute to excess burden of tuberculosis in men. We conducted a study of social contact surveys to evaluate contact patterns relevant to tuberculosis transmission. Available data describe 21 surveys in 17 countries and show profound differences in sex-based and age-based patterns of contact. Adults reported more adult contacts than children. Children preferentially mixed with women in all surveys (median sex assortativity 58%, interquartile range [IQR] 57%-59% for boys, 61% [IQR 60%-63%] for girls). Men and women reported sex-assortative mixing in 80% and 95% of surveys (median sex assortativity 56% [IQR 54%-58%] for men, 59% [IQR 57%-63%] for women). Sex-specific patterns of contact with adults were similar at home and outside the home for children; adults reported greater sex assortativity outside the home in most surveys. Sex assortativity in adult contacts likely contributes to sex disparities in adult tuberculosis burden by amplifying incidence among men
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