10,029 research outputs found
HUMAN CAPITAL NEEDS OF BLACK LAND-GRANT INSTITUTIONS
Labor and Human Capital, Teaching/Communication/Extension/Profession,
Large wind turbines: A utility option for the generation of electricity
The wind resource is such that wind energy generation has the potential to save 6-7 quads of energy nationally. Thus, the Federal Government is sponsoring and encouraging the development of cost effective and reliable wind turbines. One element of the Federal Wind Energy Programs, Large Horizontal Axis Wind Turbine Development, is managed by the NASA Lewis Research Center for the Department of Energy. There are several ongoing wind system development projects oriented primarily toward utility application within this program element. In addition, a comprehensive technology program supporting the wind turbine development projects is being conducted. An overview is presented of the NASA activities with emphasis on application of large wind turbines for generation of electricity by utility systems
Large wind turbines: A utility option for the generation of electricity
The economic and technical potential of wind energy in the United States is discussed. Particular attention is given to the status of wind turbine operational experience as well as the environmental posture of the technology
LEAH interdisciplinary training program
This article describes the Leadership Education in Adolescent Health (LEAH) interdisciplinary training program in the United States. The Maternal and Child Health Bureau authorized by legislation provides monies to train leaders in adolescent health through a competitive grant process. Currently, seven academic medical centers have funding to provide leadership in adolescent health (LEAH) training in five core disciplines: medicine, nursing, psychology, social work and nutrition. LEAH training programs both ensure high clinical competence in core disciplines serving adolescents and prepare trainees for leadership positions in adolescent health and public health care realms. Together, these programs trained almost 1000 long-term trainees across these five disciplines, and graduates from these programs are working in 45 of the 50 states within the United States. About 90% of these graduates are working with maternal and child/adolescent health populations, and almost all have held leadership positions in the areas of public health, advocacy, public policy, academic medical centers and/or clinical care settings
String spectra near some null cosmological singularities
We construct cosmological spacetimes with null Kasner-like singularities as
purely gravitational solutions with no other background fields turned on. These
can be recast as anisotropic plane-wave spacetimes by coordinate
transformations. We analyse string quantization to find the spectrum of string
modes in these backgrounds. The classical string modes can be solved for
exactly in these time-dependent backgrounds, which enables a detailed study of
the near singularity string spectrum, (time-dependent) oscillator masses and
wavefunctions. We find that for low lying string modes(finite oscillation
number), the classical near-singularity string mode functions are non-divergent
for various families of singularities. Furthermore, for any infinitesimal
regularization of the vicinity of the singularity, we find a tower of string
modes of ultra-high oscillation number which propagate essentially freely in
the background. The resulting picture suggests that string interactions are
non-negligible near the singularity.Comment: Latex, 30pgs; v2. minor clarifications, references adde
Humpback and Fin Whaling in the Gulf of Maine from 1800 to 1918
The history of whaling in the Gulf of Maine was reviewed primarily to estimate removals of humpback whales, Megaptera novaeangliae, especially during the 19th century. In the decades from 1800 to 1860, whaling effort consisted of a few localized, small-scale, shore-based enterprises on the coast of Maine and Cape Cod, Mass. Provincetown and Nantucket schooners occasionally conducted short cruises for humpback whales in New England waters. With the development of bomb-lance technology at mid century, the ease of killing humpback whales and fin whales, Balaenoptera physalus, increased. As a result, by the 1870’s there was considerable local interest in hunting rorquals (baleen whales in the family Balaenopteridae, which include the humpback and fin whales) in the Gulf of Maine. A few schooners were specially outfitted to take rorquals in the late 1870’s and 1880’s although their combined annual take was probably no more than a few tens of whales. Also in about 1880, fishing steamers began to be used to hunt whales in the Gulf of Maine. This steamer fishery grew to include about five vessels regularly engaged in whaling by the mid 1880’s but dwindled to only one vessel by the end of the decade. Fin whales constituted at least half of the catch, which exceeded 100 animals in some years. In the late 1880’s and thereafter, few whales were taken by whaling vessels in the Gulf of Maine
Decomposition, Condensation Defects, and Fusion
In this paper we outline the application of decomposition to condensation defects and their fusion rules. Briefly, a condensation defect is obtained by gauging a higher-form symmetry along a submanifold, and so there is a natural interplay with notions of decomposition, the statement that d-dimensional quantum field theories with global (Formula presented.) -form symmetries are equivalent to disjoint unions of other quantum field theories. We will also construct new (sometimes non-invertible) defects, and compute their fusion products, again utilizing decomposition. An important role will be played in all these analyses by theta angles for gauged higher-form symmetries, which can be used to select individual universes in a decomposition
Evaluation of Effectiveness of Pheasant Flushing Bars in Iowa Hayfields
A three year study on 394 acres of hayfields revealed an overall reduction in hen mortality of 38 percent through the use of flushing bars. This was significant at the .01 probability level. For the individual years, only 1954 showed a significant reduction in hayfield mortality, the observed 54 percent decrease being significant at the .05 probability level. The bars were most effective in flushing hens that were in the hay hut not sitting on the nest at the instant before the mower passed. A large proportion of hens on the nest was saved if incubation had not been started. Flushing bars were more effective in the afternoon than the forenoon hours. Effectiveness was well correlated with the condition of the hay crop; as the density and height of the hay increased, the effectiveness of the bar decreased rapidly. A possible security threshold factor related to the density of the cover, which may influence the likelihood a hen will flush, is suggested. It is not known if the use of the flushing bar actually resulted in additional pheasants in the fall populations; there was no noticeable increase attributable to their use. The principle of carrying capacity may act to cancel any initial gain resulting from the use of flushing bars
Toward the End of Time
The null-brane space-time provides a simple model of a big crunch/big bang
singularity. A non-perturbative definition of M-theory on this space-time was
recently provided using matrix theory. We derive the fermion couplings for this
matrix model and study the leading quantum effects. These effects include
particle production and a time-dependent potential. Our results suggest that as
the null-brane develops a big crunch singularity, the usual notion of
space-time is replaced by an interacting gluon phase. This gluon phase appears
to constitute the end of our conventional picture of space and time.Comment: 31 pages, reference adde
Impact Ionization in ZnS
The impact ionization rate and its orientation dependence in k space is
calculated for ZnS. The numerical results indicate a strong correlation to the
band structure. The use of a q-dependent screening function for the Coulomb
interaction between conduction and valence electrons is found to be essential.
A simple fit formula is presented for easy calculation of the energy dependent
transition rate.Comment: 9 pages LaTeX file, 3 EPS-figures (use psfig.sty), accepted for
publication in PRB as brief Report (LaTeX source replaces raw-postscript
file
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