5,712 research outputs found
Effects of a feeding strategy to increase intramuscular fat content of pork under the conditions of organic farming
In an ongoing study, the effect of the implementation of a specific feeding strategy using a high portion of home-grown grain legumes on the intramuscular fat (IMF) content of pork, is assessed under different conditions on organic farms in Germany and Austria. Preliminary results indicate that variation in the IMF content seems to be higher between farms than between treatments within each farm
Hedonic Price Indexes for Personal Computer Operating Systems and Productivity Suites
Results of hedonic price regressions for personal computer operating systems and productivity suites advertised in PC World magazine by retail vendors during the time period 1984 to 2000 are reported. Among the quality attribute variables we use are new measures capturing the presence of network effects in personal computer operating systems, such as connectivity and compatibility, and product integration among components of productivity suites. Average annual growth rates of quality-adjusted prices of personal computer operating systems range from -15 to -18 percent, while those for productivity suites generally range between -13 and -16 percent. Price declines are generally greater in the latter half of the samples.
Computer graphics application in the engineering design integration system
The computer graphics aspect of the Engineering Design Integration (EDIN) system and its application to design problems were discussed. Three basic types of computer graphics may be used with the EDIN system for the evaluation of aerospace vehicles preliminary designs: offline graphics systems using vellum-inking or photographic processes, online graphics systems characterized by direct coupled low cost storage tube terminals with limited interactive capabilities, and a minicomputer based refresh terminal offering highly interactive capabilities. The offline line systems are characterized by high quality (resolution better than 0.254 mm) and slow turnaround (one to four days). The online systems are characterized by low cost, instant visualization of the computer results, slow line speed (300 BAUD), poor hard copy, and the early limitations on vector graphic input capabilities. The recent acquisition of the Adage 330 Graphic Display system has greatly enhanced the potential for interactive computer aided design
Bilateral Migration Measures
The size of migration corridors is typically compared based on the size or rate of the flow. Migration flow counts fail to control for heterogeneity in the population size of regions. Migration rates (or intensities) adjust for population size of either the sending or the receiving region, but not both. To this end, this paper proposes two alternative measures of bilateral migration that express the size of origin-destination corridors in relation to the total migration flows during a period or the total population. The proposed Standardized Migration Affinity (SMA) index and Standardized Migration Velocity (SMV) index enable us to describe migration systems of different geographical scales and identify prominent migration corridors that are disguised when studying bilateral migrant flow counts or rates. Using examples of internal migration in China, we illustrate the application of the proposed measures at various geographic levels
Direct multiscale coupling of a transport code to gyrokinetic turbulence codes
Direct coupling between a transport solver and local, nonlinear gyrokinetic
calculations using the multiscale gyrokinetic code TRINITY [M. Barnes, Ph.D.
thesis, arxiv:0901.2868] is described. The coupling of the microscopic and
macroscopic physics is done within the framework of multiscale gyrokinetic
theory, of which we present the assumptions and key results. An assumption of
scale separation in space and time allows for the simulation of turbulence in
small regions of the space-time grid, which are embedded in a coarse grid on
which the transport equations are implicitly evolved. This leads to a reduction
in computational expense of several orders of magnitude, making
first-principles simulations of the full fusion device volume over the
confinement time feasible on current computing resources. Numerical results
from TRINITY simulations are presented and compared with experimental data from
JET and ASDEX Upgrade plasmas.Comment: 12 pages, 13 figures, invited paper for 2009 APS-DPP meeting,
submitted to Phys. Plasma
R-symmetry and Supersymmetry Breaking at Finite Temperature
We analyze the spontaneous symmetry breaking at finite temperature
for the simple O'Raifeartaigh-type model introduced in [1] in connection with
spontaneous supersymmetry breaking. We calculate the finite temperature
effective potential (free energy) to one loop order and study the thermal
evolution of the model. We find that the R-symmetry breaking occurs through a
second order phase transition. Its associated meta-stable supersymmetry
breaking vacuum is thermodynamically favored at high temperatures and the model
remains trapped in this state by a potential barrier, as the temperature lowers
all the way until T=0.Comment: 19 pages, 4 figures - Minor revisions, references added. To appear in
JHE
The Half-lives of La and La
The half-lives of La and La were determined via gamma
spectroscopy and high-precision ionization chamber measurements. The results
are 18.930(6) h for La and 4.59(4) h for La compared to the
previously compiled values of 19.5(2) h and 4.8(2) h, respectively. The new
results represent an improvement in the precision and accuracy of both values.
These lanthanum isotopes comprise a medically interesting system with positron
emitter La and Auger electron emitter La forming a matched pair
for internal diagnostics and therapeutics. The precise half-lives are necessary
for proper evaluation of their value in medicine and for a more representative
tabulation of nuclear data.Comment: 11 pages, 3 figure
Cylindrical gravitational waves in expanding universes: Models for waves from compact sources
New boundary conditions are imposed on the familiar cylindrical gravitational
wave vacuum spacetimes. The new spacetime family represents cylindrical waves
in a flat expanding (Kasner) universe. Space sections are flat and nonconical
where the waves have not reached and wave amplitudes fall off more rapidly than
they do in Einstein-Rosen solutions, permitting a more regular null inifinity.Comment: Minor corrections to references. A note added in proo
On the Thermal History of Calculable Gauge Mediation
Many messenger models with realistic gaugino masses are based on meta-stable
vacua. In this work we study the thermal history of some of these models.
Analyzing R-symmetric models, we point out that while some of the known
messenger models clearly prefer the supersymmetric vacuum, there is a vast
class of models where the answer depends on the initial conditions. Along with
the vacuum at the origin, the high temperature thermal potential also possesses
a local minimum far away from the origin. This vacuum has no analog at zero
temperature. The first order phase transition from this vacuum into the
supersymmetric vacuum is parametrically suppressed, and the theory, starting
from that vacuum, is likely to evolve to the desired gauge-mediation vacuum. We
also comment on the thermal evolution of models without R-symmetry.Comment: 22 pages. V2: Comments on the SM effects added. Minor corrections.
Reference added. Valuable discussion with S. Abel, J. Jaeckel and V. Khoze
acknowledged. V3: Types of EOGM explicitly defined in the introduction.
Discussions about the phase transitions expanded. Typo corrected. Journal
versio
Radiative Transfer in Star Formation: Testing FLD and Hybrid Methods
We perform a comparison between two radiative transfer algorithms commonly
employed in hydrodynamical calculations of star formation: grey flux limited
diffusion and the hybrid scheme, in addition we compare these algorithms to
results from the Monte-Carlo radiative transfer code MOCASSIN. In disc like
density structures the hybrid scheme performs significantly better than the FLD
method in the optically thin regions, with comparable results in optically
thick regions. In the case of a forming high mass star we find the FLD method
significantly underestimates the radiation pressure by a factor of ~100.Comment: 4 Pages; to appear in the proceedings of 'The Labyrinth of Star
Formation', Crete, 18-22 June 201
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