439 research outputs found
ILRI in Asia: an assessment of priorities for Asian livestock research and development
The purpose of this discussion paper is, firstly, to promote debate amongst potential clients of ILRI's research in South and South-East Asia on what ILRI could do in these regions, in collaboration with the NARS, which will assist the development of the livestock industries and, secondly, to provide advice to the ILRI Board and management on the rational for ILRI involvement in the regions, the nature of that involvement, and the mechanisms and process by which ILRI might maximise the benefits from its investment into research and development, particularly in these regions. The paper looks initially at the economic trends in selected countries in both regions and assesses the likely impact of this on dietary preferences and priorities. Having established the potential demands in the regions for the major livestock products (meat, milk, draft-power, eggs and, to a lesser extent, leather, wool and hair) in the next decade or so, the ways in which deficits in supply can be met from existing systems are assessed. The major constraints to improved production are identified and the role that technologically based research can play in alleviating these constraints is examined. The discussion paper then canvasses options for ILRI's participation, facilitation and leadership in some areas of priority research for the region and some possible mechanisms by which ILRI might achieve such objectives are detailed
Market Outlets for Minnesota Fruits.
This archival publication may not reflect current scientific knowledge or recommendations. Current information available from University of Minnesota Agricultural Experiment Station: http://www.maes.umn.edu
Geotomography with solar and supernova neutrinos
We show how by studying the Earth matter effect on oscillations of solar and
supernova neutrinos inside the Earth one can in principle reconstruct the
electron number density profile of the Earth. A direct inversion of the
oscillation problem is possible due to the existence of a very simple analytic
formula for the Earth matter effect on oscillations of solar and supernova
neutrinos. From the point of view of the Earth tomography, these oscillations
have a number of advantages over the oscillations of the accelerator or
atmospheric neutrinos, which stem from the fact that solar and supernova
neutrinos are coming to the Earth as mass eigenstates rather than flavour
eigenstates. In particular, this allows reconstruction of density profiles even
over relatively short neutrino path lengths in the Earth, and also of
asymmetric profiles. We study the requirements that future experiments must
meet to achieve a given accuracy of the tomography of the Earth.Comment: 35 pages, 7 figures; minor textual changes in section
Constraints on the Local Sources of Ultra High-Energy Cosmic Rays
Ultra high-energy cosmic rays (UHECRs) are believed to be protons accelerated
in magnetized plasma outflows of extra-Galactic sources. The acceleration of
protons to ~10^{20} eV requires a source power L>10^{47} erg/s. The absence of
steady sources of sufficient power within the GZK horizon of 100 Mpc, implies
that UHECR sources are transient. We show that UHECR "flares" should be
accompanied by strong X-ray and gamma-ray emission, and that X-ray and
gamma-ray surveys constrain flares which last less than a decade to satisfy at
least one of the following conditions: (i) L>10^{50} erg/s; (ii) the power
carried by accelerated electrons is lower by a factor >10^2 than the power
carried by magnetic fields or by >10^3 than the power in accelerated protons;
or (iii) the sources exist only at low redshifts, z<<1. The implausibility of
requirements (ii) and (iii) argue in favor of transient sources with L>10^{50}
erg/s.Comment: 7 pages, 1 figure, submitted to JCA
Ab Initio Calculation of the Lattice Distortions induced by Substitutional Ag- and Cu- Impurities in Alkali Halide Crystals
An ab initio study of the doping of alkali halide crystals (AX: A = Li, Na,
K, Rb; X = F, Cl, Br, I) by ns2 anions (Ag- and Cu-) is presented. Large active
clusters with 179 ions embedded in the surrounding crystalline lattice are
considered in order to describe properly the lattice relaxation induced by the
introduction of substitutional impurities. In all the cases considered, the
lattice distortions imply the concerted movement of several shells of
neighbors. The shell displacements are smaller for the smaller anion Cu-, as
expected. The study of the family of rock-salt alkali halides (excepting CsF)
allows us to extract trends that might be useful at a predictive level in the
study of other impurity systems. Those trends are presented and discussed in
terms of simple geometric arguments.Comment: LaTeX file. 8 pages, 3 EPS pictures. New version contains
calculations of the energy of formation of the defects with model clusters of
different size
Dynamical properties of liquid Al near melting. An orbital-free molecular dynamics study
The static and dynamic structure of liquid Al is studied using the orbital
free ab-initio molecular dynamics method. Two thermodynamic states along the
coexistence line are considered, namely T = 943 K and 1323 K for which X-ray
and neutron scattering data are available. A new kinetic energy functional,
which fulfills a number of physically relevant conditions is employed, along
with a local first principles pseudopotential. In addition to a comparison with
experiment, we also compare our ab-initio results with those obtained from
conventional molecular dynamics simulations using effective interionic pair
potentials derived from second order pseudopotential perturbation theory.Comment: 15 pages, 12 figures, 2 tables, submitted to PR
Origin and Evolution of Saturn's Ring System
The origin and long-term evolution of Saturn's rings is still an unsolved
problem in modern planetary science. In this chapter we review the current
state of our knowledge on this long-standing question for the main rings (A,
Cassini Division, B, C), the F Ring, and the diffuse rings (E and G). During
the Voyager era, models of evolutionary processes affecting the rings on long
time scales (erosion, viscous spreading, accretion, ballistic transport, etc.)
had suggested that Saturn's rings are not older than 100 My. In addition,
Saturn's large system of diffuse rings has been thought to be the result of
material loss from one or more of Saturn's satellites. In the Cassini era, high
spatial and spectral resolution data have allowed progress to be made on some
of these questions. Discoveries such as the ''propellers'' in the A ring, the
shape of ring-embedded moonlets, the clumps in the F Ring, and Enceladus' plume
provide new constraints on evolutionary processes in Saturn's rings. At the
same time, advances in numerical simulations over the last 20 years have opened
the way to realistic models of the rings's fine scale structure, and progress
in our understanding of the formation of the Solar System provides a
better-defined historical context in which to understand ring formation. All
these elements have important implications for the origin and long-term
evolution of Saturn's rings. They strengthen the idea that Saturn's rings are
very dynamical and rapidly evolving, while new arguments suggest that the rings
could be older than previously believed, provided that they are regularly
renewed. Key evolutionary processes, timescales and possible scenarios for the
rings's origin are reviewed in the light of tComment: Chapter 17 of the book ''Saturn After Cassini-Huygens'' Saturn from
Cassini-Huygens, Dougherty, M.K.; Esposito, L.W.; Krimigis, S.M. (Ed.) (2009)
537-57
Faddeev description of two-hole–one-particle motion and the single-particle spectral function
Measurement of the CP-Violating Asymmetry Amplitude sin2
We present results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 88 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0bar from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay-time distributions in such events. We measure sin2beta = 0.741 +/- 0.067 (stat) +/- 0.033 (syst) and |lambda| = 0.948 +/- 0.051 (stat) +/- 0.017 (syst). The magnitude of lambda is consistent with unity, in agreement with the Standard Model expectation of no direct CP violation in these modes
Search for strong gravity in multijet final states produced in pp collisions at √s=13 TeV using the ATLAS detector at the LHC
A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at √s = 13TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1TeV. No excess is seen at large HT and limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT > 5.8 TeV are excluded. Limits are also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions
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