349 research outputs found
Primary Productivity in Lake Cochrane, South Dakota, During and After Sediment-Control Dam Construction
Lake Cochrane was selected for this study because of its history of superior water transparency (Haertel 1972, 1976b). Significant amounts of silt and chemicals enter the lake with runoff at 3 locations (Haertel unpublished data). Restriction or impediment of runoff at these locations should result in improved water transparency (Haertel 1976b, Siegel 1975). Therefore, East Dakota Conservancy Sub-District and the South Dakota Department of Wildlife, Parks, and Forestry decided to impede runoff waters by means of 3 sediment-control dams incorporated into the perimeter road system of the lake and financed through a grant from the Environmental Protection Agency (Siegel 1975) (Figure 1). The dams were designed to slow the movement of runoff water allowing sediment particles and sorbed nutrients to settle out . The objectives of this study were to: (1) evaluate the oxygen light and dark bottle method as a means of estimating primary productivity, and (2) estimate, during the open-water seasons, spatial and temporal variation of certain water quality parameters in Lake Cochrane during and after construction of the sediment-control dams
Lattice thermal conductivity of disordered NiPd and NiPt alloys
Numerical calculations of lattice thermal conductivity are reported for the
binary alloys NiPd and NiPt. The present work is a continuation of an earlier
paper by us [PRB, 72, 214207 (2005)]which had developed a theoretical framework
for the calculation of configuration-averaged lattice thermal conductivity and
thermal diffusivity in disordered alloys. The formulation was based on the
augmented space theorem combined with a scattering diagram technique. In this
paper we shall show dependence of the lattice thermal conductivity on a series
of variables like phonon frequency, temperature and alloy composition. The
temperature dependence of and its realtion to the measured thermal
conductivity is discussed. The concentration dependence of appears to
justify the notion of a minimum thermal conductivity as discussed by Kittel,
Slack and others. We also study the frequency and composition dependence of the
thermal diffusivity averaged over modes. A numerical estimate of this quantity
gives an idea about the location of mobility edge and the fraction of states in
the frequency spectrum which is delocalized.Comment: 23 pages, 18 figure
Exact Solution of Photon Equation in Stationary G\"{o}del-type and G\"{o}del Space-Times
In this work the photon equation (massless Duffin-Kemmer-Petiau equation) is
written expilicitly for general type of stationary G\"{o}del space-times and is
solved exactly for G\"{o}del-type and G\"{o}del space-times. Harmonic
oscillator behaviour of the solutions is discussed and energy spectrum of
photon is obtained.Comment: 9 pages,RevTeX, no figure, revised for publicatio
Electronic structure, mechanical and thermodynamic properties of ThN from first-principles calculations
Lattice parameter, electronic structure, mechanical and thermodynamic
properties of ThN are systematically studied using the projector-augmented-wave
method and the generalized gradient approximation based on the density
functional theory. The calculated electronic structure indicates the important
contributions of Th 6\emph{d}and 5\emph{f} states to the Fermi-level electron
occupation. Through Bader analysis it is found that the effective valencies in
ThN can be represented as Th N. Elastic constant
calculations shows that ThN is mechanically stable and elastically anisotropic.
Furthermore, the melting curve of ThN is presented up to 120 GPa. Based on the
phonon dispersion data, our calculated specific heat capacities including both
lattice and conduction-electron contributions agree well with experimental
results in a wide range of temperature.Comment: 16 pages, 8 figure
Mobbing y síntomas depresivos en enfermeros de un hospital nacional de Lima 2023
El objetivo general de la presente investigación es determinar la relación entre el
mobbing y los síntomas depresivos que sufren los enfermeros en un hospital
nacional de Lima en el año 2023. El tipo de investigación es básica, el enfoque
es cuantitativo y el nivel es correlacional. Se aplicó el Cuestionario de Conductas
Negativas – Revisado (NAQ-R) y el Inventario de Depresión de Beck – II (BDI –
II) a 70 enfermeros del servicio de hospitalización de un hospital nacional de
Lima. Los resultados nos muestran que 31% de enfermeros encuestados sufre
de mobbing y el 7% presentan síntomas depresivos. Además, el Rho de
Spearman de la correlación entre estas dos variables es de 0.518, con una
significancia de p < 0.001. En conclusión, el mobbing se relaciona de manera
directa y significativa con los síntomas depresivos en los enfermeros de un
Hospital Nacional de Lima
- …