2,400 research outputs found
The neutron charge form factor in helium-3
In order to measure the charge form factor of the neutron, , one
needs to use a neutron bound in a nuclear target. We calculate the change in
the form factor for a neutron bound in , with respect to the free case,
using several versions of the quark meson coupling model. It is found that the
form factor may be suppressed by as much as 12% at with
respect to that of the free neutron.Comment: 13 pages including 2 ps figure
On achieving near-optimal “Anti-Bayesian” Order Statistics-Based classification fora asymmetric exponential distributions
This paper considers the use of Order Statistics (OS) in the theory of Pattern Recognition (PR). The pioneering work on using OS for classification was presented in [1] for the Uniform distribution, where it was shown that optimal PR can be achieved in a counter-intuitive manner, diametrically opposed to the Bayesian paradigm, i.e., by comparing the testing sample to a few samples distant from the mean - which is distinct from the optimal Bayesian paradigm. In [2], we showed that the results could be extended for a few symmetric distributions within the exponential family. In this paper, we attempt to extend these results significantly by considering asymmetric distributions within the exponential family, for some of which even the closed form expressions of the cumulative distribution functions are not available. These distributions include the Rayleigh, Gamma and certain Beta distributions. As in [1] and [2], the new scheme, referred to as Classification by Moments of Order Statistics (CMOS), attains an accuracy very close to the optimal Bayes’ bound, as has been shown both theoretically and by rigorous experimental testing
Estimates of genetic parameters of distal limb fracture and superficial digital flexor tendon injury in UK Thoroughbred racehorses
A retrospective cohort study of distal limb fracture and superficial digital flexor tendon (SDFT) injury in Thoroughbred racehorses was conducted using health records generated by the British Horseracing Authority (BHA) between 2000 and 2010. After excluding records of horses that had both flat and jump racing starts, repeated records were reduced to a single binary record per horse (<i>n</i> = 66,507, 2982 sires), and the heritability of each condition was estimated using residual maximum likelihood (REML) with animal logistic regression models. Similarly, the heritability of each condition was estimated for the flat racing and jump racing populations separately. Bivariate mixed models were used to generate estimates of genetic correlations between SDFT injury and distal limb fracture.
The heritability of distal limb fracture ranged from 0.21 to 0.37. The heritability of SDFT injury ranged from 0.31 to 0.34. SDFT injury and distal limb fracture were positively genetically correlated. These findings suggest that reductions in the risk of the conditions studied could be attempted using targeted breeding strategies
Entropy Bounds and Dark Energy
Entropy bounds render quantum corrections to the cosmological constant
finite. Under certain assumptions, the natural value of is
of order the observed dark energy density , thereby
resolving the cosmological constant problem. We note that the dark energy
equation of state in these scenarios is over
cosmological distances, and is strongly disfavored by observational data.
Alternatively, in these scenarios might account for the diffuse dark
matter component of the cosmological energy density.Comment: 6 pages, Latex. Added discussion of non-cosmological limits on
holographic dark energy. Version to appear in Physics Letters
Quantum Scattering from Classical Field Theory
We show that scattering amplitudes between initial wave packet states and
certain coherent final states can be computed in a systematic weak coupling
expansion about classical solutions satisfying initial value conditions. The
initial value conditions are such as to make the solution of the classical
field equations amenable to numerical methods. We propose a practical procedure
for computing classical solutions which contribute to high energy two particle
scattering amplitudes. We consider in this regard the implications of a recent
numerical simulation in classical SU(2) Yang-Mills theory for multiparticle
scattering in quantum gauge theories and speculate on its generalization to
electroweak theory. The generalization of our results to complex trajectories
allows its application to it any wave packet to coherent state transition.
Finally, we discuss the relevance of these results to the issues of baryon
number violation and multiparticle scattering at high energies.Comment: 20 pages, JHU-TIPAC-940003, HUTP-A0/007, Latex, uses prepictex.tex,
pictex.tex, and postpictex.tex (available by ftp from [email protected]) to
produce figure
Effect of gluon-exchange pair-currents on the ratio G(E(P))/G(M(P))
The effect of one-gluon-exchange (OGE) pair-currents on the ratio for the proton is investigated within a nonrelativistic
constituent quark model (CQM) starting from nucleon wave
functions, but with relativistic corrections. We found that the OGE
pair-currents are important to reproduce well the ratio .
With the assumption that the OGE pair-currents are the driving mechanism for
the violation of the scaling law we give a prediction for the ratio of the neutron.Comment: 5 pages, 4 figure
Dissolved oxygen resources and waste assimilative capacity of the La Grange Pool, Illinois River
Bibliography: p. 26.Enumeration continues through succeeding title
The effect of neutrinos on the matter distribution as probed by the Intergalactic Medium
We present a suite of full hydrodynamical cosmological simulations that
quantitatively address the impact of neutrinos on the (mildly non-linear)
spatial distribution of matter and in particular on the neutral hydrogen
distribution in the Intergalactic Medium (IGM), which is responsible for the
intervening Lyman-alpha absorption in quasar spectra. The free-streaming of
neutrinos results in a (non-linear) scale-dependent suppression of power
spectrum of the total matter distribution at scales probed by Lyman-alpha
forest data which is larger than the linear theory prediction by about 25% and
strongly redshift dependent. By extracting a set of realistic mock quasar
spectra, we quantify the effect of neutrinos on the flux probability
distribution function and flux power spectrum. The differences in the matter
power spectra translate into a ~2.5% (5%) difference in the flux power spectrum
for neutrino masses with Sigma m_{\nu} = 0.3 eV (0.6 eV). This rather small
effect is difficult to detect from present Lyman-alpha forest data and nearly
perfectly degenerate with the overall amplitude of the matter power spectrum as
characterised by sigma_8. If the results of the numerical simulations are
normalized to have the same sigma_8 in the initial conditions, then neutrinos
produce a smaller suppression in the flux power of about 3% (5%) for Sigma
m_{\nu} = 0.6 eV (2
sigma C.L.), comparable to constraints obtained from the cosmic microwave
background data or other large scale structure probes.Comment: 38 pages, 21 figures. One section and references added. JCAP in pres
Effects of replacing soybean meal with xylose-treated soybean meal on performance of nursing Awassi ewes and fattening lambs
Two experiments were conducted to evaluate the effect of replacing soybean meal with xylose-treated soybean meal (soypass meal; SPM) on performance of nursing Awassi ewes and fattening lambs. In Experiment 1, lasting for eight weeks, 39 Awassi ewes and their lambs were randomly assigned to three diets. Diets were formulated by replacing soybean meal from the basal diet (CON-SBM; n=13) with 50% (50% SPM; n=13) and 100% (100% SPM; n=13) SPM. Initial and final weights of the ewes were not different (P>0.55) among diets. Total gain and average daily gain (ADG) of lambs were similar (P=0.44) among diets. Ewes fed the CON-SBM diet tended (P<0.09) to have lower milk yields than those fed the 50% SPM and 100% SPM diets. No differences (P>0.38) in milk component percentages among diets were observed. In Experiment 2, lasting for 63 days, twenty weaned lambs were used to determine the effects of replacing soybean meal with SPM on growth performance. Diets were either soybean meal (SBM; n=10) or SPM (SPM; n=10). Nutrient intake and digestibility were not different between diets. However, rumen undegradable protein intake was greater (P<0.05) for the SPM diet than for the SBM diet. Final body weight, ADG and the feed conversion ratio were similar (P>0.05) between the diets. Results suggest that replacement of soybean meal with soypass meal is not likely to produce any production benefits in nursing Awassi ewes and fattening lambs except for the slight improvement of milk yield
- …