664 research outputs found
A stopped Delta-Matter Source in Heavy Ion Collisions at 10 GeV/n
We predict the formation of highly dense baryon-rich resonance matter in
Au+Au collisions at AGS energies. The final pion yields show observable signs
for resonance matter. The Delta(1232) resonance is predicted to be the dominant
source for pions of small transverse momenta. Rescattering effects --
consecutive excitation and deexcitation of Deltas -- lead to a long apparent
lifetime (> 10 fm/c) and rather large volumina (several 100 fm^3) of the
Delta-matter state. Heavier baryon resonances prove to be crucial for reaction
dynamics and particle production at AGS.Comment: 17 pages, 5 postscript figures, uses psfig.sty and revtex.st
Three-body problem at finite temperature and density
We derive practical three-body equations for the equal-time three-body Green
function in matter. Our equations describe both bosons and fermions at finite
density and temperature, and take into account all possible two-body
sub-processes allowed by the underlying Hamiltonian.Comment: 24 pages, revtex
Evaluation of Maine Coon cat behavior during three different management situations
Today, cats are one of the most widespread and beloved companion animals: they share their life with people and are perceived as social partners by their owner. The knowledge and understanding of cat-human communication and of the behavior exhibited in response to different emotions is essential to improve the management of housed cats. The aim of this study was to analyze and compare the behavior of cats in three different situations that can occur in house cats' lives. Ten Maine Coon cats, four males and six females, ranging in age from one to 13 years, belonging to a single private owner and managed under the same conditions, were exposed randomly to three different contexts for five minutes (waiting for food, isolation in unknown environment, and brushing). All the situations were video-recorded and subsequently analyzed. The behaviors oriented to environment, oriented to food bowl, locomotion, active interactions, yawning, lip licking and swallowing, and salivation mainly characterized waiting for food, while isolation appears principally characterized by behaviors such as hiding, scratching, worried positions, and exploration. Withdrawal, passive interactions, aggressive behaviors, facial discomfort, and purring characterized brushing. Vocalizations were significantly more frequent during isolation and brushing than during waiting for food, but it is possible that the characteristics of the vocalizations in these two situations are different. Our principal finding is that cats showed different behavioral patterns in the three situations and, in particular, their behavior during brushing was very different than in the two other situations. It can be hypothesized that these different behavioral responses are due to the different emotional states elicited by each of the three challenging and potentially stressful situations. Further investigation is being carried out to better understand cats' behaviors and emotions to improve cats' management in the household
A series of new conjugated oligothiophenes for organic electronics
Thiophene oligomers and polymers can be found in a huge number of materials with applications in the field of Organic Electronics. Chemical and electrochemical syntheses along with electrochemical studies and complete characterization of a series of new conjugated oligothiophene derivatives are reported. Two different molecular architectures, D-A (donor-acceptor) and A-D-A (acceptor-donor-acceptor), were taken into account. The results from voltammetric experiments and optical studies confirm the close relationship between the structure of these compounds and their electrochemical behaviour. This series of oligothiophenes shows low bandgaps, a mandatory requirement for their use in Organic Electronics, and, clearly, they are promising candidates for future synthetic studies in order to modify their optical and electrochemical properties to achieve better performances as organic semiconductors
High performance liquid chromatography coupled with mass spectrometry for/and nanomaterials: an overview
The story of mass spectrometry applied to the nanoparticles world is very young but actually it is expected to evolve as one of the most powerful tool for the characterization of the smaller-size nanoparticles in terms of composition, size, shape, surface chemistry, because of its versatility, sensitivity, reliability and the possibility to be coupled with high performance chromatographic separation techniques. A short overview on different fields where liquid chromatography coupled with mass spectrometry, nanomaterials and nanotechnology come together is herein given
QCD equation of state in a virial expansion
We describe recent three-flavor QCD lattice data for the pressure, speed of
soun d and interaction measure at nonzero temperature and vanishing chemical
potentia l within a virial expansion. For the deconfined phase we use a
phenomenological model which includes non-pert urbative effects from dimension
two gluon condensates that reproduce the free en ergy of quenched QCD very
well. The hadronic phase is parameterized by a generalized resonance-gas model.
Furthermore, we extend this approach to finite quark densities introducing an
ex plicit -dependence of the interaction. We calculate pressure,
quark-number density, entropy and energy density and compare to results of
lattice calculatio ns. We, additionally, investigate the structure of the phase
diagram by calculating the isobaric and isentropic lines as well as the
critical endpoint in the ()-plane.Comment: 9 pages, 11 figures. Submitted to Phys. Rev.
AVALIAÇÃO IN VITRO DA ATIVIDADE ANTIBACTERIANA DO MEL DA ABELHA MELIPONA MANDACAIA (MANDAÇAIA), FRENTE AOS MICRORGANISMOS: STAPHYLOCOCCUS AUREUS, PSEUDOMONAS AERUGINOSA E ESCHERICHIA COLI
Survey on housing, management and welfare of dairy cattle in tie-stalls in western Italian Alps
In the Alps, the traditional breeding system for dairy cattle is based on the alternation between a free ranging period on mountain ranges during the summer, and an indoor period in tie-stalls in the cold season. Several welfare issues may arise in tie-stall housing systems. We described the situation in 47 farms in three villages in Western Italy, trying to identify possible relationships among structural and management characteristics, animal health and behaviour traits. A long duration of the grazing periods, associated with frequent manure removal during the housing period, are probably key factors for limiting the occurrence of lameness. Teat trauma are more common in narrower stalls. Getting up behaviour is unnatural in most of the visited farms. Some lacks in the farmers' knowledge of animal behaviour was pointed out. Some structural and management characteristics are strictly related to geographic constraints. However, situation permitting, some expedients may be achieved for improving welfare levels
Dibaryons with Strangeness: their Weak Nonleptonic Decay using SU(3) Symmetry and how to find them in Relativistic Heavy-Ion Collisions
Weak SU(3) symmetry is successfully applied to the weak hadronic decay
amplitudes of octet hyperons. Weak nonmesonic and mesonic decays of various
dibaryons with strangeness, their dominant decay modes, and lifetimes are
calculated. Production estimates for BNL's Relativistic Heavy-Ion Collider are
presented employing wave function coalescence. Signals for detecting strange
dibaryon states in heavy-ion collisions and revealing information about the
unknown hyperon-hyperon interactions are outlined.Comment: 4 pages, 2 figures, uses RevTeX, discussion about the model of the
weak decay and experimental signals extended, references update
TOPS project: Development of new fast timing plastic scintillators.
In particle physics charged particles are measured exploiting many different detection strategies. The plastic scintillators are cheap, versatile and show good time response, thus are traditionally employed as timing detectors. TOPS (Time Of flight Plastic Scintillators) is an R&D project devoted to the synthesis and characterization of a novel class of plastic scintillators. Liquid and solid sam- ples of tens of new scintillators have been tested and characterized. Some of them (2N, 1N, 2B, P2, T2) have shown a larger light output with respect to antracene, a standard benchmark material, and good timing properties. In order to improve the matching between the scintillators emission and the optimal trasmittive region in the absorption spectra, a doping material has been added as wave-shifter. The use of POPOP as doping improved the performances of a fraction of the scintillator samples. Based on the comparison of the light output values in measurements with cosmic rays, a selection of the most promising scintillators has been investigated also from the timing point of view. The scintillation time characteristics of the TOPS plastic samples have been studied with minimum ionizing particles using a commercial plastic scintillator BC-412 as a reference. The light output and timing properties have been also investigated with proton beams at different energies (70, 120, 170, 220 MeV) and show promising results providing a time of flight measure- ments accuracy of 150–300ps. In this contribution, preliminary results obtained with this new class of scintillators developed in the TOPS project will be presented
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