5,126 research outputs found
Current Methods Used for the Control of Files on Beef Cattle in South Dakota
A survey of pesticide use conducted in 1982 involving 230 livestock producers in eastern South Dakota has revealed that files and lice are considered the most important external pests of livestock. Data from the survey are currently being processed and results will be available in early 1983
Plasma heating in the very early and decay phases of solar flares
In this paper we analyze the energy budgets of two single-loop solar flares
under the assumption that non-thermal electrons are the only source of plasma
heating during all phases of both events. The flares were observed by the
Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Geostationary
Operational Environmental Satellite (GOES) on September 20, 2002 and March 17,
2002, respectively. For both investigated flares we derived the energy fluxes
contained in non-thermal electron beams from the RHESSI observational data
constrained by observed GOES light-curves. We showed that energy delivered by
non-thermal electrons was fully sufficient to fulfil the energy budgets of the
plasma during the pre-heating and impulsive phases of both flares as well as
during the decay phase of one of them. We concluded that in the case of the
investigated flares there was no need to use any additional ad-hoc heating
mechanisms other than heating by non-thermal electrons.Comment: 22 pages, 10 figures, The Astrophysical Journal (accepted, March
2011
Episodic X-ray Emission Accompanying the Activation of an Eruptive Prominence: Evidence of Episodic Magnetic Reconnection
We present an X-ray imaging and spectroscopic study of a partially occulted
C7.7 flare on 2003 April 24 observed by RHESSI that accompanied a prominence
eruption observed by TRACE. (1) The activation and rise of the prominence
occurs during the preheating phase of the flare. The initial X-ray emission
appears as a single coronal source at one leg of the prominence and it then
splits into a double source. Such a source splitting happens three times, each
coinciding with an increased X-ray flux and plasma temperature, suggestive of
fast reconnection in a localized current sheet and an enhanced energy release
rate. In the late stage of this phase, the prominence displays a helical
structure. These observations are consistent with the tether-cutting and/or
kink instability model for triggering solar eruptions. (2) The eruption of the
prominence takes place during the flare impulsive phase. Since then, there
appear signatures predicted by the classical CSHKP model of two-ribbon flares
occurring in a vertical current sheet trailing an eruption. These signatures
include an EUV cusp and current-sheet-like feature (or ridge) above it. There
is also X-ray emission along the EUV ridge both below and above the cusp, which
in both regions appears closer to the cusp at higher energies in the thermal
regime. This trend is reversed in the nonthermal regime. (3) Spectral analysis
indicates thermal X-rays from all sources throughout the flare, while during
the impulsive phase there is additional nonthermal emission which primarily
comes from the coronal source below the cusp. This source also has a lower
temperature, a higher emission measure, and a much harder nonthermal spectrum
than the upper sources.Comment: 8 pages, 5 figures, submitted to Ap
Quenched QCD with domain wall fermions
We report on simulations of quenched QCD using domain wall fermions, where we
focus on basic questions about the formalism and its ability to produce
expected low energy hadronic physics for light quarks. The work reported here
is on quenched lattices at and 5.85, using values
for the length of the fifth dimension between 10 and 48. We report results for
parameter choices which lead to the desired number of flavors, a study of
undamped modes in the extra dimension and hadron masses.Comment: Contribution to Lattice '98. Presented by R. Mawhinney. 3 pages, 3
figure
Dynamical QCD thermodynamics with domain wall fermions
We present results from numerical simulations of full, two flavor QCD
thermodynamics at N_t=4 with domain wall fermions. For the first time a
numerical simulation of the full QCD phase transition displays a low
temperature phase with spontaneous chiral symmetry breaking but intact flavor
symmetry and a high temperature phase with the full SU(2) x SU(2) chiral flavor
symmetry.Comment: LATTICE98(hightemp
Progress Toward Establishing a Pest Management Program for the Face Fly, Musca autumnalis DeGeer, in South Dakota
The face fly is similar in appearance to the house fly (Figure 1) with a few minor differences. The female face fly is somewhat larger and darker. The large eyes of the male face fly nearly touch on the front of the head while the eyes of the house fly are further apart. The female face fly has a silvery stripe around the eyes whereas the stripe on the house fly is more golden. A dark spot between the eyes of the face fly is more rounded than that of the house fly and the abdomen of the face fly is darker and more slate-grey in color
The domain wall fermion chiral condensate in quenched QCD
We examine the chiral limit of domain wall fermions in quenched QCD. One
expects that in a quenched simulation, exact fermion zero modes will give a
divergent, 1/m behavior in the chiral condensate for sufficiently small valence
quark masses. Unlike other fermion formulations, domain wall fermions clearly
demonstrate this behavior.Comment: LATTICE98(spectrum), G. R. Fleming presented talk, 5 pages, 3
figures, corrected typos in printed versio
Congruence of Human Organizations and Missions: Theory versus Data
1999 Command and Control Research and Technology Symposium (CCRTS), June 29 - July 1, 1999, U.S. Naval War College, Rhode IslandIn this paper, we present a methodology for quantifying the degree of fit between a mission and an
organization based on the closeness between the task structure (i.e., resource requirements and task
interdependence) and the DM-asset allocation across the organization (i.e., amount and distribution
of resource capabilities among DMs, and organizational processes). This closeness is based on
three main characteristics of organizational performance: workload balance, communication
requirements, and DM-DM dependence. These characteristics are affected, in turn, by the
interactions and interdependencies of the organizational processes and the demands of the mission
scenario. Invariably, coordination is essential to achieve good performance because the
information required for decisionmaking is often distributed. However, excessive DM-DM
communication and coordination are harmful to performance, since they increase the processing
workload/overhead that delays task execution. Performance improvements can be obtained by
changing the structure and processes of an organization to decrease the requisite coordination,
while balancing the levels of workload across the organization and reducing inter DM dependence.This work was supported by the Office of Naval Research under contract # N00014-00-1-0101
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