1,813 research outputs found
Event-by-Event Fluctuations of Particle Ratios in Heavy-Ion Collisions
We study event-by-event dynamical fluctuations of various particle ratios at
different energies. We assume that particle production in final state is due to
chemical equilibrium processes. We compare results from resonance gas model
with available experimental data. At SPS energies, the model can very well
reproduce the experimentally measured fluctuations. We make predictions for
dynamical fluctuations of strangeness and non-strangeness particle ratios. We
found that the energy-dependence is non-monotonic. Furthermore, we found that
fluctuations strongly depend on particle ratios.Comment: 6 pages, 2 figure, 1 tabl
Finite temperature quantum correlations in quark states and quantum spin models
The entanglement at finite temperatures are analyzed by using thermal models
for colored quarks making up the hadron physical states. We have found that
these quantum correlations entirely vanish at . For
temperatures larger than the correlations are classical. Also we worked
out the entanglement for the transverse Ising spin chain. In dependence on both
temperature and transverse field we can identify a certain
region, where the quantum effects are likely to dominate the system. We suggest
the mutual information as a quantitative measure for the correlations in ground
state.Comment: 15 pages, 10 eps-figure
The influence of strange quarks on QCD phase diagram and chemical freeze-out: Results from the hadron resonance gas model
We confront the lattice results on QCD phase diagram for two and three
flavors with the hadron resonance gas model. Taking into account the
truncations in the Taylor-expansion of energy density done on the
lattice at finite chemical potential , we find that the hadron resonance
gas model under the condition of constant describes very well the
lattice phase diagram. We also calculate the chemical freeze-out curve
according to the entropy density . The -values are taken from lattice QCD
simulations with two and three flavors. We find that this condition is
excellent in reproducing the experimentally estimated parameters of the
chemical freeze-out.Comment: 5 pages, 3 figures and 1 table Talk given at VIIIth international
conference on ''Strangeness in Quark Matter'' (SQM 2004), Cape Town, South
Africa, Sep. 15-20 200
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Antibiotic resistance evolved via inactivation of a ribosomal RNA methylating enzyme.
Modifications of the bacterial ribosome regulate the function of the ribosome and modulate its susceptibility to antibiotics. By modifying a highly conserved adenosine A2503 in 23S rRNA, methylating enzyme Cfr confers resistance to a range of ribosome-targeting antibiotics. The same adenosine is also methylated by RlmN, an enzyme widely distributed among bacteria. While RlmN modifies C2, Cfr modifies the C8 position of A2503. Shared nucleotide substrate and phylogenetic relationship between RlmN and Cfr prompted us to investigate evolutionary origin of antibiotic resistance in this enzyme family. Using directed evolution of RlmN under antibiotic selection, we obtained RlmN variants that mediate low-level resistance. Surprisingly, these variants confer resistance not through the Cfr-like C8 methylation, but via inhibition of the endogenous RlmN C2 methylation of A2503. Detection of RlmN inactivating mutations in clinical resistance isolates suggests that the mechanism used by the in vitro evolved variants is also relevant in a clinical setting. Additionally, as indicated by a phylogenetic analysis, it appears that Cfr did not diverge from the RlmN family but from another distinct family of predicted radical SAM methylating enzymes whose function remains unknown
Matter-Antimatter Asymmetry in the Large Hadron Collider
The matter-antimatter asymmetry is one of the greatest challenges in the
modern physics. The universe including this paper and even the reader
him(her)self seems to be built up of ordinary matter only. Theoretically, the
well-known Sakharov's conditions remain the solid framework explaining the
circumstances that matter became dominant against the antimatter while the
universe cools down and/or expands. On the other hand, the standard model for
elementary particles apparently prevents at least two conditions out of them.
In this work, we introduce a systematic study of the antiparticle-to-particle
ratios measured in various and collisions over the last three
decades. It is obvious that the available experimental facilities turn to be
able to perform nuclear collisions, in which the matter-antimatter asymmetry
raises from at AGS to at LHC. Assuming that the final
state of hadronization in the nuclear collisions takes place along the
freezeout line, which is defined by a constant entropy density, various
antiparticle-to-particle ratios are studied in framework of the hadron
resonance gas (HRG) model. Implementing modified phase space and distribution
function in the grand-canonical ensemble and taking into account the
experimental acceptance, the ratios of antiparticle-to-particle over the whole
range of center-of-mass-energies are very well reproduced by the HRG model.
Furthermore, the antiproton-to-proton ratios measured by ALICE in
collisions is also very well described by the HRG model. It is likely to
conclude that the LHC heavy-ion program will produce the same particle ratios
as the program implying the dynamics and evolution of the system would not
depend on the initial conditions. The ratios of bosons and baryons get very
close to unity indicating that the matter-antimatter asymmetry nearly vanishes
at LHC.Comment: 9 pages, 5 eps-figures, revtex4-styl
The Role and Breeds, Management Systems, Productivity and Development Strategies of Goats in Indonesia: A Review
Small ruminants like sheep and goats are important for a larger part of the Indonesian rural population. The major breeds of goats found in Indonesia are the Kacang and Etawah goats. The biological and economic function of goats have long been recognised. Besides producing animal products, they also provide manure to maintain soil fertility. Goats are kept as an important component of farming activities, particularly by smallholders. The existing goat husbandry is normally the result of hundreds of years of tradition. Different systems of goat production have evolved in response to factors such as climate, need of the owner, economic environment, and level of technology available. The general aim in the management of goat production units is to increase the productivity. The biological productivity of goats is determined by the fundamental processes of reproduction, growth and development and death. Key production traits which should be considered for improving goats’ productivity are adaptability and productivity conditions, reproductive rate, growth rate and carcass value. The objectives of this paper are to review the role and breeds of goats, current management systems and productivity for goats with particular reference to Indonesia, and to discuss the development strategies that may have specific applications in the Indonesian situation
Influencing Factors of Infestation of Endo and Ectoparasites on Hair Sheep in Tropical Ecuador
120 hair sheep were tested for faecal, skin and blood parasites. After three parasitological studies in humid Sucumbíos, it was proved that the parasitic charge is influenced by different factors. In the case of air temperature and humidity there was no variation detected between the seasons, although the parasitical charge rose in the course of this study. With regard to parasitic charge some systematic differences were found between the farming systems. Prophylactic measures such as rotational grazing, guarantee the food alternatives in the case of grass shortage, the strategic treatment with de-wormers and removal of excrement and garbage were recommended
Goats Husbandry for Extensive Use
Twenty-six crossbred dams of the F3 generation and twenty Cashmere dams were surveyed with regard to their productivity, hardiness and resilience. The endoparasite situation was recorded for both the dams and lambs of both breeding groups. Productivity data of both breeding groups included figures on reproduction and dressing percentage. Using a scoring key, the rate of claw growth of both breeding groups was recorded as a possibility of comparison
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