104,431 research outputs found
Skatole pattern during the growth period 50 to 100 kg liveweight in entire male pigs of the crossbreed combinations YDxLYD and HxLYD kept in groups of entire male pigs or in groups with dominant female pigs
1. Dominant females do not decrease the skatole and androstenone concentration in entire male pigs being dominated during the growth period from 50-100 kg liveweight (see fig. 1 and 3).
2. The amount of entire male pigs having higher skatole concentrations in blood – corresponding to skatole in backfat > 0.15 µg/g – are surprisingly high at 50 kg and 75 kg liveweight compared to 100 kg (10, 9 and 13 entire male pigs).
3. Furthermore it is not the same pigs having high skatole concentrations during the period from 50 over 75 to 100 kg liveweight.
4. The crossbreed HxLYD had significant higher skatole concentration in backfat at slaughter (100 kg liveweight) compared to the crossbreed YDxLYD (P<0.05)(see fig. 2). However, there was no significant difference in androstenone concentration in backfat at
100 kg liveweight between the 2 crossbreeds (see fig. 3)
A near field cosmology study of heavy elements in very metal-poor stars
Studying a range of old metal-poor stars provides information over
cosmological timescales of our Galaxy. Such studies are indicative of the
pristine gases and evolution of the Milky Way. Deriving stellar parameters and
abundances from high-resolution observations of stars at various stellar
evolution stages (including old dwarfs and RR Lyrae), allows us to use these
abundances as tracers of an even earlier progenitor population. Here, we carry
out a detailed abundance study of mainly heavy elements (Z > 38), i.e.
neutron-capture elements, which we at low metallicities ([Fe/H] < -2.5) take as
pure supernova type II products. A comparison of the derived abundances to type
II supernova yields of heavy elements provides knowledge of the old stellar
generations as well as properties of neutron-capture formation sites.Comment: 6 pages, 3 figure
Reduction of the hydrophobic attraction between charged solutes in water
We examine the effective force between two nanometer scale solutes in water
by Molecular Dynamics simulations. Macroscopic considerations predict a strong
reduction of the hydrophobic attraction between solutes when the latter are
charged. This is confirmed by the simulations which point to a surprising
constancy of the effective force between oppositely charged solutes at contact,
while like charged solutes lead to significantly different behavior between
positive and negative pairs. The latter exhibit the phenomenon of ``like-charge
attraction" previously observed in some colloidal dispersions.Comment: 4 pages, 5 figure
A fundamental measure theory for the sticky hard sphere fluid
We construct a density functional theory (DFT) for the sticky hard sphere
(SHS) fluid which, like Rosenfeld's fundamental measure theory (FMT) for the
hard sphere fluid [Phys. Rev. Lett. {\bf 63}, 980 (1989)], is based on a set of
weighted densities and an exact result from scaled particle theory (SPT). It is
demonstrated that the excess free energy density of the inhomogeneous SHS fluid
is uniquely defined when (a) it is solely a function of the
weighted densities from Kierlik and Rosinberg's version of FMT [Phys. Rev. A
{\bf 42}, 3382 (1990)], (b) it satisfies the SPT differential equation, and (c)
it yields any given direct correlation function (DCF) from the class of
generalized Percus-Yevick closures introduced by Gazzillo and Giacometti [J.
Chem. Phys. {\bf 120}, 4742 (2004)]. The resulting DFT is shown to be in very
good agreement with simulation data. In particular, this FMT yields the correct
contact value of the density profiles with no adjustable parameters. Rather
than requiring higher order DCFs, such as perturbative DFTs, our SHS FMT
produces them. Interestingly, although equivalent to Kierlik and Rosinberg's
FMT in the case of hard spheres, the set of weighted densities used for
Rosenfeld's original FMT is insufficient for constructing a DFT which yields
the SHS DCF.Comment: 11 pages, 3 figure
Competition of hydrophobic and Coulombic interactions between nano-sized solutes
The solvation of charged, nanometer-sized spherical solutes in water, and the
effective, solvent-induced force between two such solutes are investigated by
constant temperature and pressure Molecular Dynamics simulations of model
solutes carrying various charge patterns. The results for neutral solutes agree
well with earlier findings, and with predictions of simple macroscopic
considerations: substantial hydrophobic attraction may be traced back to strong
depletion (``drying'') of the solvent between the solutes. This hydrophobic
attraction is strongly reduced when the solutes are uniformly charged, and the
total force becomes repulsive at sufficiently high charge; there is a
significant asymmetry between anionic and cationic solute pairs, the latter
experiencing a lesser hydrophobic attraction. The situation becomes more
complex when the solutes carry discrete (rather than uniform) charge patterns.
Due to antagonistic effects of the resulting hydrophilic and hydrophobic
``patches'' on the solvent molecules, water is once more significantly depleted
around the solutes, and the effective interaction reverts to being mainly
attractive, despite the direct electrostatic repulsion between solutes.
Examination of a highly coarse-grained configurational probability density
shows that the relative orientation of the two solutes is very different in
explicit solvent, compared to the prediction of the crude implicit solvent
representation. The present study strongly suggests that a realistic modeling
of the charge distribution on the surface of globular proteins, as well as the
molecular treatment of water are essential prerequisites for any reliable study
of protein aggregation.Comment: 20 pages, 25 figure
Nitrate leaching from silage maize
During the last 20 years the area with maize in Denmark has increased dramatically and reached 163,000 ha in 2008. Silage maize is easy to grow, is a suitable fodder for cows and goes well with grass-clover in the diet. This means that silage maize is often found in crop rotations with grass-clover on sandy soils in western Denmark. The ploughing in of grass-clover fields poses a serious risk of increased nitrate leaching on a coarse sandy soil, even when carried out in spring. With increased maize cropping, there is therefore a need for strategies to reduce nitrate leaching after ploughing of grass-clover.In the ICROFS project, OrgGrass, we examined the effect of catch crop and slurry application on nitrate leaching from maize after a spring-ploughed grass-clover
Comments on "State equation for the three-dimensional system of 'collapsing' hard spheres"
A recent paper [I. Klebanov et al. \emph{Mod. Phys. Lett. B} \textbf{22}
(2008) 3153; arXiv:0712.0433] claims that the exact solution of the
Percus-Yevick (PY) integral equation for a system of hard spheres plus a step
potential is obtained. The aim of this paper is to show that Klebanov et al.'s
result is incompatible with the PY equation since it violates two known cases:
the low-density limit and the hard-sphere limit.Comment: 4 pages; v2: title chang
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