3,073 research outputs found
Jet Energy Density in Hadron-Hadron Collisions at High Energies
The average particle multiplicity density dN/deta is the dynamical quantity
which reflects some regularities of particle production in low-pT range. The
quantity is an important ingredient of z-scaling. Experimental results on
charged particle density are available for pp, pA and AA collisions while
experimental properties of the jet density are still an open question. The goal
of this work is to find the variable which will reflect the main features of
the jet production in low transverse energy range and play the role of the
scale factor for the scaling function psi(z) and variable z in data
z-presentation. The appropriate candidate is the variable we called "scaled jet
energy density". Scaled jet energy density is the probability to have a jet
with defined ET in defined xT and pseudorapidity regions. The PYTHIA6.2 Monte
Carlo generator is used for calculation of scaled jet energy density in
proton-proton collisions over a high energy range (sqrt s = 200-14000 GeV) and
at eta = 0. The properties of the new variable are discussed and sensitivity to
"physical scenarios" applied in the standard Monte Carlo generator is noted.
The results of scaled jet energy density at LHC energies are presented and
compared with predictions based on z-scaling.Comment: 11 pages, LaTeX, 8 figures, Presented at the XVII International
Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics
& Quantum Chromodynamics", Dubna, Russia, September 27 - October 2, 200
Superposition effect and clan structure in forward-backward multiplicity correlations
The main purpose of this paper is to discuss the link between
forward-backward multiplicity correlations properties and the shape of the
corresponding final charged particle multiplicity distribution in various
classes of events in different collisions. It is shown that the same mechanism
which explains the shoulder effect and the H_n vs. n oscillations in charged
particle multiplicity distributions, i.e., the weighted superposition of
different classes of events with negative binomial properties, reproduces
within experimental errors also the forward-backward multiplicity correlation
strength in e+e- annihilation at LEP energy and allows interesting predictions
for pp collisions in the TeV energy region, to be tested at LHC, for instance
with the ALICE detector. We limit ourselves at present to study substructures
properties in hadron-hadron collisions and e+e- annihilation; they are examined
as ancillary examples in the conviction that their understanding might be
relevant also in other more complex cases.Comment: 16 page
Probability landscapes for integrative genomics
<p>Abstract</p> <p>Background</p> <p>The comprehension of the gene regulatory code in eukaryotes is one of the major challenges of systems biology, and is a requirement for the development of novel therapeutic strategies for multifactorial diseases. Its bi-fold degeneration precludes brute force and statistical approaches based on the genomic sequence alone. Rather, recursive integration of systematic, whole-genome experimental data with advanced statistical regulatory sequence predictions needs to be developed. Such experimental approaches as well as the prediction tools are only starting to become available and increasing numbers of genome sequences and empirical sequence annotations are under continual discovery-driven change. Furthermore, given the complexity of the question, a decade(s) long multi-laboratory effort needs to be envisioned. These constraints need to be considered in the creation of a framework that can pave a road to successful comprehension of the gene regulatory code.</p> <p>Results</p> <p>We introduce here a concept for such a framework, based entirely on systematic annotation in terms of probability profiles of genomic sequence using any type of relevant experimental and theoretical information and subsequent cross-correlation analysis in hypothesis-driven model building and testing.</p> <p>Conclusion</p> <p>Probability landscapes, which include as reference set the probabilistic representation of the genomic sequence, can be used efficiently to discover and analyze correlations amongst initially heterogeneous and un-relatable descriptions and genome-wide measurements. Furthermore, this structure is usable as a support for automatically generating and testing hypotheses for alternative gene regulatory grammars and the evaluation of those through statistical analysis of the high-dimensional correlations between genomic sequence, sequence annotations, and experimental data. Finally, this structure provides a concrete and tangible basis for attempting to formulate a mathematical description of gene regulation in eukaryotes on a genome-wide scale.</p
Effects of Repeated Intrathecal Triamcinolone-Acetonide Application on Cerebrospinal Fluid Biomarkers of Axonal Damage and Glial Activity in Multiple Sclerosis Patients
Multiple sclerosis (MS) is the most common inflammatory disease of the central nervous system in young adults. Over time, the disease progresses and, with accumulating disability, symptoms such as spasticity may occur. Although several treatment options are available, some patients may not respond to first-line therapeutics. However, some of these patients may benefit from intrathecally administered triamcinolone-acetonide (TCA), a derivative of glucocorticosteroids (GCS).GCSmay have neurotoxic effects, and cell apoptosis may occur. The aim of this study was to investigate the effects of TCA on biomarkers in the cerebrospinal fluid (CSF) suggestive of neurodegeneration
Response to Commentary by W. Jost on: Pharmaceutical, Biological, and Clinical Properties of Botulinum Neurotoxin Type A Products
Studies of multiplicity in relativistic heavy-ion collisions
In this talk I'll review the present status of charged particle multiplicity
measurements from heavy-ion collisions. The characteristic features of
multiplicity distributions obtained in Au+Au collisions will be discussed in
terms of collision centrality and energy and compared to those of p+p
collisions. Multiplicity measurements of d+Au collisions at 200 GeV
nucleon-nucleon center-of-mass energy will also be discussed. The results will
be compared to various theoretical models and simple scaling properties of the
data will be identified.Comment: "Focus on Multiplicity" Internationsl Workshop on Particle
Multiplicity in Relativistic Heavy Ion Collisions, Bari, Italy, June 17-19,
2003, 16 pages, 15 figure
Endocrine Disrupting Contaminants—Beyond the Dogma
Descriptions of endocrine disruption have largely been associated with wildlife and driven by observations documenting estrogenic, androgenic, antiandrogenic, and antithyroid actions. These actions, in response to exposure to ecologically relevant concentrations of various environmental contaminants, have now been established in numerous vertebrate species. However, many potential mechanisms and endocrine actions have not been studied. For example, the DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] metabolite, p,p′-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] is known to disrupt prostaglandin synthesis in the uterus of birds, providing part of the explanation for DDT-induced egg shell thinning. Few studies have examined prostaglandin synthesis as a target for endocrine disruption, yet these hormones are active in reproduction, immune responses, and cardiovascular physiology. Future studies must broaden the basic science approach to endocrine disruption, thereby expanding the mechanisms and endocrine end points examined. This goal should be accomplished even if the primary influence and funding continue to emphasize a narrower approach based on regulatory needs. Without this broader approach, research into endocrine disruption will become dominated by a narrow dogma, focusing on a few end points and mechanisms
IgG autoantibody to brain beta tubulin III associated with cytokine cluster-II discriminate cerebral malaria in central India
We investigated the significance of these self-reactive antibodies in clinically well-defined groups of P. falciparum infected patients manifesting mild malaria (MM), severe non-cerebral malaria (SM), or cerebral malaria (CM) and in control subjects from Gondia, a malaria epidemic site in central India using quantitative immunoprinting and multivariate statistical analyses. A two-fold complete-linkage hierarchical clustering allows classifying the different patient groups and to distinguish the CM from the others on the basis of their profile of IgG reactivity to brain proteins defined by PANAMA Blot. We identified beta tubulin III (TBB3) as a novel discriminant brain antigen in the prevalence of CM. In addition, circulating IgG from CM patients highly react with recombinant TBB3. Overall, correspondence analyses based on singular value decomposition show a strong correlation between IgG anti-TBB3 and elevated concentration of cluster-II cytokine (IFNγ, IL1β, TNFα, TGFβ) previously demonstrated to be a predictor of CM in the same populatio
Charged particle densities from Au+Au collisions at sqrt{s_{NN}}=130 GeV
We present charged particle densities as a function of pseudorapidity and
collision centrality for the 197Au+197Au reaction at sqrt{s_{NN}}=130 GeV. An
integral charged particle multiplicity of 3860+/-300 is found for the 5% most
central events within the pseudorapidity range -4.7 <= eta <= 4.7. At
mid-rapidity an enhancement in the particle yields per participant nucleon pair
is observed for central events. Near to the beam rapidity, a scaling of the
particle yields consistent with the ``limiting fragmentation'' picture is
observed. Our results are compared to other recent experimental and theoretical
discussions of charged particle densities in ultra-relativistic heavy-ion
collisions.Comment: 14 pages, 4 figures; to be published in Phys. Lett.
Global Observations from PHOBOS
Particle production in Au+Au collisions has been measured in the PHOBOS
experiment at RHIC for a range of collision energies. Three empirical
observations have emerged from this dataset which require theoretical
examination. First, there is clear evidence of limiting fragmentation. Namely,
particle production in central Au+Au collisions, when expressed as
(), becomes energy independent at high energy for a
broad region of around . This energy-independent region grows
with energy, allowing only a limited region (if any) of longitudinal
boost-invariance. Second, there is a striking similarity between particle
production in e+e- and Au+Au collisions (scaled by the number of participating
nucleon pairs). Both the total number of produced particles and the
longitudinal distribution of produced particles are approximately the same in
e+e- and in scaled Au+Au. This observation was not predicted and has not been
explained. Finally, particle production has been found to scale approximately
with the number of participating nucleon pairs for . This scaling
occurs both for the total multiplicity and for high \pT particles (3 <\pT<
4.5 GeV/c).Comment: QM2002 plenary talk, 10 pages, 11 figure
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