83,631 research outputs found
Temperature, chemical potential and the rho meson
We describe some applications of the Dyson-Schwinger equations at
nonzero-(T,mu). Employing a simple model dressed-gluon propagator we determine
the boundary of the deconfinement phase transition and the medium dependence of
rho-meson properties. We introduce an extension to describe the time-evolution
of scalar and vector self energies.Comment: 6 pages, LaTeX with 3 EPS figures; Contribution to the 'International
Workshop XXVIII on Gross Properties of Nuclei and Nuclear Excitations',
Hirschegg, Austria, 16-22.01.200
The Density of States Method at Finite Chemical Potential
We study the density of states method to explore the phase diagram of the
chiral transition on the temperature and quark chemical potential plane. Four
quark flavors are used in the analysis. Though the method is quite expensive
small lattices show an indication for a triple-point connecting three different
phases on the phase diagram.Comment: 5 pages, 6 figures, talk given at 'Extreme QCD', August 2-5 2005,
Swansea, Wales, U
Personality traits in resident and migratory warbler species.
Animals are often confronted with environmental challenges and the way in which they cope with these challenges can have important fitness consequences. There is increasing evidence that individuals differ consistently in their reaction to the environment (personality traits). However, little is known about whether different life-styles (e.g., resident or migratory) influence personality traits and if so, in what manner. We compared neophobic and exploratory behaviours, both of which play an important role in personality traits, between two closely related species, the resident Sardinian warblers and the migratory garden warblers, at two different times during the year. Neophobia was tested by placing a novel object, a mop, beside the feeding dish and measuring the latency to feed (neophobia score). Exploration was tested by offering another novel object, a tube, attached to a perch at a neutral location and measuring latency to approach and investigate the tube (exploration score). Both tests were carried out at the end of the breeding season and repeated ten months later in spring. The Sardinian warblers showed consistent behavioural reactions over time. Furthermore, neophobia and exploration scores were negatively related. The garden warblers neither behaved consistently over time nor was there a correlation between neophobia and exploration. Overall, Sardinian warblers were less neophobic and more explorative than garden warblers. The different reactivity may be due to a different frequency distribution of the individuals of the two species along a reactivity axis. It can be concluded that the Sardinian warblers have personality traits. The situation is less clear in the garden warblers. Possibly, different life-styles require different organisation of behaviours
Thermodynamic properties of a simple, confining model
We study the equilibrium thermodynamics of a simple, confining, DSE-model of
2-flavour QCD at finite temperature and chemical potential. The model has two
phases: one characterised by confinement and dynamical chiral symmetry
breaking; and the other by their absence. The phase boundary is defined by the
zero of the vacuum-pressure difference between the confined and deconfined
phases. Chiral symmetry restoration and deconfinement are coincident with the
transition being of first order, except for , where it is second order.
Nonperturbative modifications of the dressed-quark propagator persist into the
deconfined domain and lead to a dispersion law modified by a
dynamically-generated, momentum-dependent mass-scale. This entails that the
Stefan-Boltzmann limit for the bulk thermodynamic quantities is attained only
for large values of temperature and chemical potential.Comment: 11 pages, LaTeX, epsfig.sty, elsart.st
The isentropic equation of state of 2-flavor QCD
Using Taylor expansions of the pressure obtained previously in studies of
2-flavor QCD at non-zero chemical potential we calculate expansion coefficients
for the energy and entropy densities up to in the quark
chemical potential. We use these series in to determine lines of
constant entropy per baryon number () that characterize the expansion of
dense matter created in heavy ion collisions. In the high temperature regime
these lines are found to be well approximated by lines of constant .
In the low temperature phase, however, the quark chemical potential is found to
increase with decreasing temperature. This is in accordance with resonance gas
model calculations. Along the lines of constant we calculate the energy
density and pressure. Within the accuracy of our present analysis we find that
the ratio for as well as the softest point of the equation
of state, , show no significant dependence on
.Comment: 7 pages, 10 figure
SkyMapper and the Southern Sky Survey - a resource for the southern sky
SkyMapper is amongst the first of a new generation of dedicated, wide-field
survey telescopes. The 1.3m SkyMapper telescope features a 5.7 square degree
field-of-view Cassegrain imager and will see first light in late 2007. The
primary goal of the facility is to conduct the Southern Sky Survey a six
colour, six epoch survey of the southern sky. The survey will provide
photometry for objects between 8th and 23rd magnitude with global photometric
accuracy of 0.03 magnitudes and astrometry to 50 mas. This will represent a
valuable scientific resource for the southern sky and in addition provide a
basis for photometric and astrometric calibration of imaging data.Comment: 6 pages, 4 figures, proceedings of ESO Calibration Workshop 200
A Lesson in Scaling 6LoWPAN -- Minimal Fragment Forwarding in Lossy Networks
This paper evaluates two forwarding strategies for fragmented datagrams in
the IoT: hop-wise reassembly and a minimal approach to directly forward
fragments. Minimal fragment forwarding is challenged by the lack of forwarding
information at subsequent fragments in 6LoWPAN and thus requires additional
data at nodes. We compared the two approaches in extensive experiments
evaluating reliability, end-to-end latency, and memory consumption. In contrast
to previous work and due to our alternate setup, we obtained different results
and conclusions. Our findings indicate that direct fragment forwarding should
be deployed only with care, since higher packet transmission rates on the
link-layer can significantly reduce its reliability, which in turn can even
further reduce end-to-end latency because of highly increased link-layer
retransmissions.Comment: If you cite this paper, please use the LCN reference: M. S. Lenders,
T. C. Schmidt, M. W\"ahlisch. "A Lesson in Scaling 6LoWPAN - Minimal Fragment
Forwarding in Lossy Networks." in Proc. of IEEE LCN, 201
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