1,867 research outputs found
Particle abundances and spectra in the hydrodynamical description of relativistic nuclear collisions with light projectiles
We show that a hydrodynamical model with continuous particle emission instead
of sudden freeze out may explain both the observed strange particle and pion
abundances and transverse mass spectra for light projectile at SPS energy. We
found that the observed enhancement of pion production corresponds, within the
context of continuous emission, to the maximal entropy production.Comment: 11 pages, 2 figure
Ames hypopituitary dwarf mice demonstrate imbalanced myelopoiesis between bone marrow and spleen
Ames hypopituitary dwarf mice are deficient in growth hormone, thyroid-stimulating hormone, and prolactin. The phenotype of these mice demonstrates irregularities in the immune system with skewing of the normal cytokine milieu towards a more anti-inflammatory environment. However, the hematopoietic stem and progenitor cell composition of the bone marrow (BM) and spleen in Ames dwarf mice has not been well characterized. We found that there was a significant decrease in overall cell count when comparing the BM and spleen of 4-5 month old dwarf mice to their littermate controls. Upon adjusting counts to differences in body weight between the dwarf and control mice, the number of granulocyte-macrophage progenitors, confirmed by immunophenotyping and colony-formation assay was increased in the BM. In contrast, the numbers of all myeloid progenitor populations in the spleen were greatly reduced, as confirmed by colony-formation assays. This suggests that there is a shift of myelopoiesis from the spleen to the BM of Ames dwarf mice; however, this shift does not appear to involve erythropoiesis. The reasons for this unusual shift in spleen to marrow hematopoiesis in Ames dwarf mice are yet to be determined but may relate to the decreased hormone levels in these mice
Formation of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC and their Identification by the ALICE Experiment
We present a phenomenological model which describes the formation of a
Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and
at the LHC, and its decay to non-strange baryons and Strangelets. We describe
the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in
an event-by-event mode, the very forward, baryon-rich phase space 5.6 < \eta <
7.2 in 5.5 A TeV central Pb + Pb collisions. We present results of simulations
for the response of the CASTOR calorimeter, and in particular to the traversal
of Strangelets.Comment: 4 pages, 4 figures, to appear in the proceedings of the 26th ICR
CASTOR: Centauro and Strange Object Research in nucleus-nucleus collisions at LHC
We describe the CASTOR detector designed to probe the very forward,
baryon-rich rapidity region in nucleus-nucleus collisions at the LHC. We
present a phenomenological model describing the formation of a QGP fireball in
a high baryochemical potential environment, and its subsequent decay into
baryons and strangelets. The model explains Centauros and the long-penetrating
component and makes predictions for the LHC.
Simulations of Centauro-type events were done. To study the response of the
apparatus to new effects different exotic species (DCC, Centauros, strangelets
etc.) were passed through the deep calorimeter. The energy deposition pattern
in the calorimeter appears to be a new clear signature of the QGP.Comment: Talk given by E. Gladysz-Dziadus for the CASTOR group, Intern.
Workshop on Nuclear Theory, 10-15 June, 2002, Bulgaria, Rila Mountains, 15
pages, 14 figure
Timbre brownfield prioritization tool to support effective brownfield regeneration.
In the last decade, the regeneration of derelict or underused sites, fully or partly located in urban areas (or so called âbrownfieldsâ), has become more common, since free developable land (or so called âgreenfieldsâ) has more and more become a scare and, hence, more expensive resource, especially in densely populated areas. Although the regeneration of brownfield sites can offer development potentials, the complexity of these sites requires considerable efforts to successfully complete their revitalization projects and the proper selection of promising sites is a pre-requisite to efficiently allocate the limited financial resources. The identification and analysis of success factors for brownfield sites regeneration can support investors and decision makers in selecting those sites which are the most advantageous for successful regeneration. The objective of this paper is to present the Timbre Brownfield Prioritization Tool (TBPT), developed as a web-based solution to assist stakeholders responsible for wider territories or clusters of brownfield sites (portfolios) to identify which brownfield sites should be preferably considered for redevelopment or further investigation. The prioritization approach is based on a set of success factors properly identified through a systematic stakeholder engagement procedure. Within the TBPT these success factors are integrated by means of a Multi Criteria Decision Analysis (MCDA) methodology, which includes stakeholders' requalification objectives and perspectives related to the brownfield regeneration process and takes into account the three pillars of sustainability (economic, social and environmental dimensions). The tool has been applied to the South Moravia case study (Czech Republic), considering two different requalification objectives identified by local stakeholders, namely the selection of suitable locations for the development of a shopping centre and a solar power plant, respectively. The application of the TBPT to the case study showed that it is flexible and easy to adapt to different local contexts, allowing the assessors to introduce locally relevant parameters identified according to their expertise and considering the availability of local data
Transition from a quark-gluon plasma in the presence of a sharp front
The effect of a sharp front separating the quark-gluon plasma phase from the
hadronic phase is investigated. Energy-momentum conservation and baryon number
conservation constrain the possible temperature jump across the front. If one
assumes that the temperature in the hadronic phase is 200 MeV , as
has been suggested by numerous results from relativistic ion collisions, one
can determine the corresponding temperature in the quark phase with the help of
continuity equations across the front. The calculations reveal that the quark
phase must be in a strongly supercooled state. The stability of this solution
with respect to minor modifications is investigated. In particular the effect
of an admixture of hadronic matter in the quark phase (e.g. in the form of
bubbles) is considered in detail. In the absence of admixture the transition
proceeds via a detonation transition and is accompanied by a substantial
super-cooling of the quark-gluon plasma phase. The detonation is accompanied by
less supercooling if a small fraction of bubbles is allowed. By increasing the
fraction of bubbles the supercooling becomes weaker and eventually the
transition proceeds via a smoother deflagration wave.Comment: 10 pages, manuscript in TeX, 9 figures available as Postscript files,
CERN-TH 6923/9
Indications for a Detonating Quark-Gluon Plasma
We propose a mechanism which naturally contains the relation of the hadronic gas produced in heavy-ion collisions at CERN. Our
starting assumption is the existence of a sharp front separating the
quark-gluon plasma phase from the hadronic phase. Energy-momentum conservation
across the front leads to the following consequences for an adiabatic process
a) The baryon chemical potential, , is approximately continuous across
the front. b) The temperature in the hadronic gas is higher than the phase
transition temperature due to superheating. c) In the region covered by the
experiments the velocity of the hadronic gas approximately equals the speed of
sound in the hadronic gas.Comment: Latex file 9 pages + 6 figures available as postscript file
Enhancement of singly and multiply strangeness in p-Pb and Pb-Pb collisions at 158A GeV/c
The idea that the reduction of the strange quark suppression in string
fragmentation leads to the enhancement of strange particle yield in
nucleus-nucleus collisions is applied to study the singly and multiply strange
particle production in p-Pb and Pb-Pb collisions at 158A GeV/c. In this
mechanism the strange quark suppression factor is related to the effective
string tension, which increases in turn with the increase of the energy, of the
centrality and of the mass of colliding system. The WA97 observation that the
strange particle enhancement increases with the increasing of centrality and of
strange quark content in multiply strange particles in Pb-Pb collisions with
respect to p-Pb collisions was accounted reasonably.Comment: 8 pages, 3 PostScript figures, in Latex form. submitted to PR
Thermal phenomenology of hadrons from 200 AGeV S+S collisions
We develop a complete and consistent description for the hadron spectra from
heavy ion collisions in terms of a few collective variables, in particular
temperature, longitudinal and transverse flow. To achieve a meaningful
comparison with presently available data, we also include the resonance decays
into our picture. To disentangle the influences of transverse flow and
resonance decays in the -spectra, we analyse in detail the shape of the
-spectra.Comment: 31 pages, 13 figs in seperate uuencoded file, for LaTeX, epsf.sty and
dvips, TPR-93-16 and BNL-(no number yet
Loss of the chromatin modifier Kdm2aa causes BrafV600E-independent spontaneous melanoma in zebrafish.
KDM2A is a histone demethylase associated with transcriptional silencing, however very little is known about its in vivo role in development and disease. Here we demonstrate that loss of the orthologue kdm2aa in zebrafish causes widespread transcriptional disruption and leads to spontaneous melanomas at a high frequency. Fish homozygous for two independent premature stop codon alleles show reduced growth and survival, a strong male sex bias, and homozygous females exhibit a progressive oogenesis defect. kdm2aa mutant fish also develop melanomas from early adulthood onwards which are independent from mutations in braf and other common oncogenes and tumour suppressors as revealed by deep whole exome sequencing. In addition to effects on translation and DNA replication gene expression, high-replicate RNA-seq in morphologically normal individuals demonstrates a stable regulatory response of epigenetic modifiers and the specific de-repression of a group of zinc finger genes residing in constitutive heterochromatin. Together our data reveal a complex role for Kdm2aa in regulating normal mRNA levels and carcinogenesis. These findings establish kdm2aa mutants as the first single gene knockout model of melanoma biology
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