9 research outputs found
Event-by-Event Analysis of Baryon-Strangeness Correlations: Pinning Down the Critical Temperature and Volume of QGP Formation
The recently proposed baryon-strangeness correlation (C_BS) is studied with a
string-hadronic transport model (UrQMD) for various energies from E_lab=4 AGeV
to \sqrt s=200 AGeV. It is shown that rescattering among secondaries can not
mimic the predicted correlation pattern expected for a Quark-Gluon-Plasma.
However, we find a strong increase of the C_BS correlation function with
decreasing collision energy both for pp and Au+Au/Pb+Pb reactions. For Au+Au
reactions at the top RHIC energy (\sqrt s=200 AGeV), the C_BS correlation is
constant for all centralities and compatible with the pp result. With
increasing width of the rapidity window, C_BS follows roughly the shape of the
baryon rapidity distribution. We suggest to study the energy and centrality
dependence of C_BS which allow to gain information on the onset of the
deconfinement transition in temperature and volume
Forward-Backward Charge Fluctuations at RHIC Energies
We use the ultra-relativistic quantum molecular dynamic UrQMD version 2.2 to
study forward backward fluctuations and compare our results with the published
data by the PHOBOS.Comment: 4 pages, 6 figures, poster presented at Strong & Electroweak Matter
(SEWM2006), BNL, United States, May 10-13 200
The Effect of Dynamical Parton Recombination on Event-by-Event Observables
Within a dynamical quark recombination model we explore various proposed
event-by-event observables sensitive to the microscopic structure of the
QCD-matter created at RHIC energies. Charge fluctuations, charge transfer
fluctuations and baryon-strangeness correlations are computed from a sample of
central Au+Au events at the highest RHIC energy available (=200
GeV). We find that for all explored observables, the calculations yield the
values predicted for a quark-gluon plasma only at early times of the evolution,
whereas the final state approaches the values expected for a hadronic gas. We
argue that the recombination-like hadronization process itself is responsible
for the disappearance of the predicted deconfinement signatures. This might
explain why no fluctuation signatures for the transition between quark and
hadronic matter was ever observed in the experimental data up to now. However,
it might also be interpreted as a clear indication for a recombination like
hadronization process at RHIC.Comment: 5 page
The genome of the green anole lizard and a comparative analysis with birds and mammals
The evolution of the amniotic egg was one of the great evolutionary innovations in the history of life, freeing vertebrates from an obligatory connection to water and thus permitting the conquest of terrestrial environments. Among amniotes, genome sequences are available for mammals and birds, but not for non-avian reptiles. Here we report the genome sequence of the North American green anole lizard, Anolis carolinensis. We find that A. carolinensis microchromosomes are highly syntenic with chicken microchromosomes, yet do not exhibit the high GC and low repeat content that are characteristic of avian microchromosomes. Also, A. carolinensis mobile elements are very young and diverseâmore so than in any other sequenced amniote genome. The GC content of this lizard genome is also unusual in its homogeneity, unlike the regionally variable GC content found in mammals and birds. We describe and assign sequence to the previously unknown A. carolinensis X chromosome. Comparative gene analysis shows that amniote egg proteins have evolved significantly more rapidly than other proteins. An anole phylogeny resolves basal branches to illuminate the history of their repeated adaptive radiations.National Science Foundation (U.S.) (NSF grant DEB-0920892)National Science Foundation (U.S.) (NSF grant DEB-0844624)National Human Genome Research Institute (U.S.
The genome of the green anole lizard and a comparative analysis with birds and mammals
The evolution of the amniotic egg was one of the great evolutionary innovations in the history of life, freeing vertebrates from an obligatory connection to water and thus permitting the conquest of terrestrial environments1. Among amniotes, genome sequences are available for mammals2 and birds3â5, but not for non-avian reptiles. Here we report the genome sequence of the North American green anole lizard, Anolis carolinensis. We find that A. carolinensis microchromosomes are highly syntenic with chicken microchromosomes, yet do not exhibit the high GC and low repeat content that are characteristic of avian microchromosomes3. Also, A. carolinensis mobile elements are very young and diverse â more so than in any other sequenced amniote genome. This lizard genomeâs GC content is also unusual in its homogeneity, unlike the regionally variable GC content found in mammals and birds6. We describe and assign sequence to the previously unknown A. carolinensis X chromosome. Comparative gene analysis shows that amniote egg proteins have evolved significantly more rapidly than other proteins. An anole phylogeny resolves basal branches to illuminate the history of their repeated adaptive radiations
The Role of NWP Filter for the Satellite Based Detection of Cumulonimbus Clouds
This study is motivated by the great importance of Cbs for aviation safety. The study investigates the role of Numerical Weather Prediction (NWP) filtering for the remote sensing of Cumulonimbus Clouds (Cbs) by implementation of about 30 different experiments, covering Central Europe. These experiments compile different stability filter settings as well as the use of different channels for the InfraRed (IR) brightness temperatures (BT). As stability filters, parameters from Numerical Weather Prediction (NWP) are used. The application of the stability filters restricts the detection of Cbs to regions with a labile atmosphere. Various NWP filter settings are investigated in the experiments. The brightness temperature information results from the infrared (IR) Spinning Enhanced Visible and InfraRed Image (SEVIRI) instrument on-board of the Meteosat Second Generation satellite and enables the detection of very cold and high clouds close to the tropopause. Various satellite channels and BT thresholds are applied in the different experiments. The satellite only approaches (no NWP filtering) result in the detection of Cbs with a relative high probability of detection, but unfortunately combined with a large False Alarm Rate (FAR), leading to a Critical Success Index (CSI) below 60% for the investigated summer period in 2016. The false alarms result from other types of very cold and high clouds. It is shown that the false alarms can be significantly decreased by application of an appropriate NWP stability filter, leading to the increase of CSI to about 70% for 2016. CSI is increased from about 70 to about 75% by application of NWP filtering for the other investigated summer period in 2017. A brief review and reflection of the literature clarify that the function of the NWP filter can not be replaced by MSG IR spectroscopy. Thus, NWP filtering is strongly recommended to increase the quality of satellite based Cb detection. Further, it has been shown that the well established convective available potential energy (CAPE) and the convection index (KO) work well as a stability filter
Baryon-Strangeness Correlations from Hadron/String- and Quark-Dynamics
Abstract. Baryon-strangeness correlations (CBS) are studied with a hadron/string transport approach (UrQMD) and a dynamical quark recombination model (quark molecular dynamics, qMD) for various energies from Elab = 4A GeV to â sNN = 200 GeV. As expected, we find that the hadron/string dynamics shows correlations similar to a simple hadron gas. In case of the quark molecular dynamics, we find that initially the CBS correlation is that of a weakly interacting QGP but changes in the process of hadronization also to the value for a hadron gas. Therefore, we conclude that the hadronization process itself makes the initial baryon strangeness correlation unobservable. To make an experimental study of this observable more feasible, we also investigate how a restriction to only charged kaons and Îâs (instead of all baryons and all strange particles) influences the theoretical result on CBS. We find that a good approximation of the full result can be obtained in this limit in the present simulation