296 research outputs found
Meta-analyses describing the variables that influence the backfat, belly fat, and jowl fat iodine value of pork carcasses
Concern about the quality of pork fat has increased in the United States over the last
decade, largely because of the increased availability and use of dried distillers grains
with solubles (DDGS) in swine diets. The iodine value (IV) of pork fat is commonly
used as an indicator of quality. To identify the factors associated with carcass fat IV,
meta-analyses were conducted to describe the relevant variables and to develop prediction
equations to assist swine nutritionists and producers in producing pork fat with
an acceptable IV. Data from 21 experiments were used to develop prediction equations
for carcass fat IV of pigs fed a relatively constant dietary iodine value product (IVP)
throughout the feeding period, and 6 experiments were used to develop prediction
equations for carcass fat IV of pigs fed a dietary IVP-reduction strategy before marketing.
Backfat, belly fat, and jowl fat IV were all highly correlated among the experiments
that measured the IV of the multiple fat depots (r ≥ 0.880; P < 0.001). As expected,
the dietary concentrations of unsaturated (primarily polyunsaturated) fatty acids
were the most important in predicting carcass fat IV. However, improved prediction
models were achieved by including variables to describe the pigs’ initial and final BW,
ADG, and carcass leanness. Increased ADG, final BW, BW range over course of the
diet, and backfat depth resulted in reduced backfat IV (P < 0.02). Belly fat IV was also
reduced with increasing final BW, BW range over course of the diet, and backfat depth
(P < 0.03). A reduced jowl fat IV was associated with an increase in backfat depth
and a lower fat-free lean index (FFLI, P < 0.02). Data analyzed to develop equations
for predicting carcass fat IV using a dietary IVP-reduction strategy indicated that the
concentrations of dietary polyunsaturated fatty acids in the initial diet were the most
important. The concentrations of dietary polyunsaturated fatty acids in the reduced-
IVP diet fed before marketing were also important in predicting the IV of carcass fat.
However, the IV of backfat was the most amenable to change using an IVP-reduction
strategy. Feeding the pigs for a longer period and to a heavier final BW resulted in a
reduced backfat IV (P ≤ 0.05). These results indicate that, although primarily determined
by dietary factors, an understanding of the other variables that influence the IV
of pork fat is necessary to reduce the likelihood of concerns with pork fat quality
Centrifugal stretching from lifetime measurements in the 170Hf ground state band
Centrifugal stretching in the deformed rare-earth nucleus 170Hf is investigated using high-precision lifetime measurements, performed with the New Yale Plunger Device at Wright Nuclear Structure Laboratory, Yale University. Excited states were populated in the fusion-evaporation reaction 124Sn(50Ti,4n)170Hf at a beam energy of 195 MeV. Recoil distance doppler shift data were recorded for the ground state band through the J=16+ level. The measured B(E2) values and transition quadrupole moments improve on existing data and show increasing β deformation in the ground state band of 170Hf. The results are compared to descriptions by a rigid rotor and by the confined β-soft rotor model. © 2013 American Physical Society
How Does CMB + BBN Constrain New Physics?
Recent cosmic microwave background (CMB) results from BOOMERANG, MAXIMA, and
DASI provide cosmological constraints on new physics that can be competitive
with those derived from Big Bang Nucleosynthesis (BBN). In particular, both CMB
and BBN can be used to place limits on models involving neutrino degeneracy and
additional relativistic degrees of freedom. However, for the case of the CMB,
these constraints are, in general, sensitive to the assumed priors. We examine
the CMB and BBN constraints on such models and study the sensitivity of ``new
physics" to the assumed priors. If we add a constraint on the age of the
universe (t_0 \ga 11 Gyr), then for models with a cosmological constant, the
range of baryon densities and neutrino degeneracy parameters allowed by the CMB
and BBN is fairly robust: , \deln \la 6, \xi_e \la
0.3. In the absence of new physics, models without a cosmological constant are
only marginally compatible with recent CMB observations (excluded at the 93%
confidence level).Comment: 6 pages, 5 figures; version to appear in Phys. Rev.
Cosmic Microwave Background constraint on residual annihilations of relic particles
Energy injected into the Cosmic Microwave Background at redshifts z<10^6 will
distort its spectrum permanently. In this paper we discuss the distortion
caused by annihilations of relic particles. We use the observational bounds on
deviations from a Planck spectrum to constrain a combination of annihilation
cross section, mass, and abundance. For particles with (s-wave) annihilation
cross section, =\sigma_0, the bound is
f[(\sigma_0/6e-27cm^3/s)(\Omega_{X\bar{X}}h^2)^2]/(m_X/MeV)<0.2, where m_X is
the particle mass, \Omega_{X\bar{X}} is the fraction of the critical density
the particle and its antiparticle contribute if they survive to the present
time, h=H_0/(100km/s/Mpc), H_0 is the Hubble constant, and f is the fraction of
the annihilation energy that interacts electromagnetically. We also compute the
less stringent limits for p-wave annihilation. We update other bounds on
residual annihilations and compare them to our CMB bound.Comment: submitted to Phys. Rev.
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