28,396 research outputs found
Design, development and delivery of one /1/ breadboard and three /3/ production units of a 75 VA integrated static inverter Monthly progress report no. 11, Mar. 1966
Breadboard model development of integrated static inverte
Design, development and delivery of one /1/ breadboard and three /3/ production units of a 75 VA integrated static inverter Monthly report no. 15
Flip-flop arrays, power transistors, epitaxial stress, and other technological developments in integrated static inverter progra
Multi-excitonic complexes in single InGaN quantum dots
Cathodoluminescence spectra employing a shadow mask technique of InGaN layers
grown by metal organic chemical vapor deposition on Si(111) substrates are
reported. Sharp lines originating from InGaN quantum dots are observed.
Temperature dependent measurements reveal thermally induced carrier
redistribution between the quantum dots. Spectral diffusion is observed and was
used as a tool to correlate up to three lines that originate from the same
quantum dot. Variation of excitation density leads to identification of exciton
and biexciton. Binding and anti-binding complexes are discovered.Comment: 3 pages, 4 figure
Limits on nu_e and anti-nu_e disappearance from Gallium and reactor experiments
The deficit observed in the Gallium radioactive source experiments is
interpreted as a possible indication of the disappearance of electron
neutrinos. In the effective framework of two-neutrino mixing we obtain
and . The compatibility of this result with the data of the Bugey and
Chooz reactor short-baseline antineutrino disappearance experiments is studied.
It is found that the Bugey data present a hint of neutrino oscillations with
and , which is compatible with the Gallium allowed region of the
mixing parameters. This hint persists in the combined analyses of Bugey and
Chooz data, of Gallium and Bugey data, and of Gallium, Bugey, and Chooz data.Comment: 21 pages. Final version to be published in Phys. Rev.
Spectroscopic signature of Alfv\'en waves damping in a polar coronal hole up to 0.4 solar radii
Between February 24-25, 2009, the EIS spectrometer onboard the Hinode
spacecraft performed special "sit & stare" observations above the South polar
coronal hole continuously over more than 22 hours. Spectra were acquired with
the 1" slit placed off-limb covering altitudes up to 0.48 R
( Mm) above the Sun surface, in order to study with EIS the
non-thermal spectral line broadenings. Spectral lines such as Fe {\sc xii}
186.88, Fe {\sc xii} 193.51, Fe {\sc xii} 195.12 and
Fe {\sc xiii} 202.04 are observed with good statistics up to high
altitudes and they have been analyzed in this study. Results show that the FWHM
of Fe {\sc xii} 195.12 line increases up to R,
then decreases higher up. EIS stray light has been estimated and removed.
Derived electron density and non-thermal velocity profiles have been used to
estimate the total energy flux transported by Alfv\'en waves off-limb in polar
coronal hole up to R. The computed Alfv\'en wave energy
flux density progressively decays with altitude from erg cm s at 0.03 R down to erg cm s at 0.4 R, with an average energy
decay rate erg cm
s. Hence, this result suggests energy deposition by Alfv\'en waves in a
polar coronal hole, thus providing a significant source for coronal heating.Comment: Physical units of the Alfv\'en wave Energy Decay Rate revised with respect to the published version. Scientific results
and conclusions unchange
STATISTICAL ISSUES IN STUDIES OF THERMOREGULATION IN FARM ANIMALS
Patterns of tympanic temperature response were identified in ad-lib-fed cattle exposed to constant or cyclic (±7 C) conditions at two levels of air temperature: 10 C and 28 C. Use of time series analysis following the DDS approach of Pandit and Wu indicate the thermoregulatory control dynamics for steers at 28±7 C were markedly different from those at the other conditions. Preliminary evaluations using the ideas of chaos and non-linear dynamics show promise of further characterization of stress responses in farm animals
Isoscaling Studies of Fission - a Sensitive Probe into the Dynamics of Scission
The fragment yield ratios were investigated in the fission of 238,233U
targets induced by 14 MeV neutrons. The isoscaling behavior was typically
observed for the isotopic chains of fragments ranging from the proton-rich to
the most neutron-rich ones. The observed high sensitivity of neutron-rich heavy
fragments to the target neutron content suggests fission as a source of
neutron-rich heavy nuclei for present and future rare ion beam facilities,
allowing studies of nuclear properties towards the neutron drip-line and
investigations of the conditions for nucleosynthesis of heavy nuclei. The
breakdowns of the isoscaling behavior around N=62 and N=80 manifest the effect
of two shell closures on the dynamics of scission. The shell closure around
N=64 can be explained by the deformed shell. The investigation of isoscaling in
the spontaneous fission of 248,244Cm further supports such conclusion. The
Z-dependence of the isoscaling parameter exhibits a structure which can be
possibly related to details of scission dynamics. The fission isoscaling
studies can be a suitable tool for the investigation of possible new pathways
to synthesize still heavier nuclei.Comment: 7 pages, 3 figures, RevTex, final version, to appear in Phys. Rev. C
as a regular articl
Livestock production system management responses to thermal challenges
The adaptive capabilities of animals and livestock production systems have been emphasized in this report. Biometeorology has a key role in rational management to meet the challenges of thermal environments. While the focus is primarily on cattle in warm or hot climates, the importance of dynamic animal responses to environmental challenges applies to all species and climates. Methods used to mitigate environmental challenges focus on heat loss/heat production balance. Under cold stress, reduction of heat loss is the key. Under heat stress, reduction of heat load or increasing heat loss are the primary management tools, although heat-tolerant animals are also available. In general, livestock with health problems and the most productive animals (e.g., highest growth rate or milk production) are at greatest risk of heat stress, thereby requiring the most attention. Risk management, by considering perceived thermal challenges, then assessing the potential consequences and acting accordingly, will reduce the impact of such challenges. Appropriate actions include: shade, sprinkling, air movement, or active cooling. Summarizing, the most important element of proactive environmental management to reduce risk is preparation: be informed, develop a strategic plan, observe and recognize animals in distress, and take appropriate tactical action
Higgs Phenomenology in Warped Extra-Dimensions with a 4th Generation
We study a warped extra-dimension scenario where the Standard Model fields
lie in the bulk, with the addition of a fourth family of fermions. We
concentrate on the flavor structure of the Higgs couplings with fermions in the
flavor anarchy ansatz. Even without a fourth family, these couplings will be
generically misaligned with respect to the SM fermion mass matrices. The
presence of the fourth family typically enhances the misalignment effects and
we show that one should expect them to be highly non-symmetrical in the
inter-generational mixing. The radiative corrections from the new
fermions and their flavor violating couplings to the Higgs affect negligibly
known experimental precision measurements such as the oblique parameters and
or . On the other hand,
processes, mediated by tree-level Higgs exchange, as well as radiative
corrections to and put some generic pressure
on the allowed size of the flavor violating couplings. But more importantly,
these couplings will alter the Higgs decay patterns as well as those of the new
fermions, and produce very interesting new signals associated to Higgs
phenomenology in high energy colliders. These might become very important
indirect signals for these type of models as they would be present even when
the KK mass scale is high and no heavy KK particle is discovered.Comment: 39 pages, 6 figure
Hints of theta_13>0 from global neutrino data analysis
Nailing down the unknown neutrino mixing angle theta_13 is one of the most
important goals in current lepton physics. In this context, we perform a global
analysis of neutrino oscillation data, focusing on theta_13, and including
recent results [Neutrino 2008, Proceedings of the XXIII International
Conference on Neutrino Physics and Astrophysics, Christchurch, New Zealand,
2008 (unpublished)]. We discuss two converging hints of theta_13>0, each at the
level of ~1sigma: an older one coming from atmospheric neutrino data, and a
newer one coming from the combination of solar and long-baseline reactor
neutrino data. Their combination provides the global estimate sin^2(theta_13) =
0.016 +- 0.010 (1sigma), implying a preference for \theta_13>0 with
non-negligible statistical significance (~90% C.L.). We discuss possible
refinements of the experimental data analyses, which might sharpen such
intriguing indication.Comment: Minor changes in the text. Matches published version in PR
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