3,602 research outputs found
Energy and centrality dependences of charged multiplicity density in relativistic nuclear collisions
Using a hadron and string cascade model, JPCIAE, the energy and centrality
dependences of charged particle pseudorapidity density in relativistic nuclear
collisions were studied. Within the framework of this model, both the
relativistic experimental data and the PHOBOS and PHENIX
data at =130 GeV could be reproduced fairly well without retuning
the model parameters. The predictions for full RHIC energy collisions
and for collisions at the ALICE energy were given. Participant nucleon
distributions were calculated based on different methods. It was found that the
number of participant nucleons, for distinguishing various theoretical models.Comment: 10 pages, 4 figures, submitted to Phy. Lett.
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
Differential entropy and time
We give a detailed analysis of the Gibbs-type entropy notion and its
dynamical behavior in case of time-dependent continuous probability
distributions of varied origins: related to classical and quantum systems. The
purpose-dependent usage of conditional Kullback-Leibler and Gibbs (Shannon)
entropies is explained in case of non-equilibrium Smoluchowski processes. A
very different temporal behavior of Gibbs and Kullback entropies is confronted.
A specific conceptual niche is addressed, where quantum von Neumann, classical
Kullback-Leibler and Gibbs entropies can be consistently introduced as
information measures for the same physical system. If the dynamics of
probability densities is driven by the Schr\"{o}dinger picture wave-packet
evolution, Gibbs-type and related Fisher information functionals appear to
quantify nontrivial power transfer processes in the mean. This observation is
found to extend to classical dissipative processes and supports the view that
the Shannon entropy dynamics provides an insight into physically relevant
non-equilibrium phenomena, which are inaccessible in terms of the
Kullback-Leibler entropy and typically ignored in the literature.Comment: Final, unabridged version; http://www.mdpi.org/entropy/ Dedicated to
Professor Rafael Sorkin on his 60th birthda
Transverse Energy Evolution as a Test of Parton Cascade Models
We propose a test of Monte Carlo Parton Cascade models based on analytic
solutions of covariant kinetic theory for longitudinally boost and transverse
translation invariant boundary conditions. We compute the evolution of the
transverse energy per unit rapidity for typical mini-jet initial conditions
expected in ultra-relativistic nuclear collisions. The kinetic theory solutions
under these conditions test the models severely because they deviate strongly
from free-streaming and also from ideal Euler and dissipative Navier-Stokes
hydrodynamical approximations. We show that the newly formulated ZPC model
passes this test. In addition, we show that the initial mini-jet density would
need to be approximately four times higher than estimated with the HIJING
generator in central Au+Au collisions at c.m. energies 200 AGeV in order that
parton cascade dynamics can be approximated by Navier-Stokes hydrodynamics.Comment: Latex 28 pages, including 5 figure (postscript embedded with psfig
Garden varieties: how attractive are recommended garden plants to butterflies?
One way the public can engage in insect conservation is through wildlife gardening, including the growing of insect-friendly flowers as sources of nectar. However, plant varieties differ in the types of insects they attract. To determine which garden plants attracted which butterflies, we counted butterflies nectaring on 11 varieties of summer-flowering garden plants in a rural garden in East Sussex, UK. These plants were all from a list of 100 varieties considered attractive to British butterflies, and included the five varieties specifically listed by the UK charity Butterfly Conservation as best for summer nectar. A total of 2659 flower visits from 14 butterfly and one moth species were observed. We performed a principal components analysis which showed contrasting patterns between the species attracted to Origanum vulgare and Buddleia davidii. The âbutterfly bushâ Buddleia attracted many nymphalines, such as the peacock, Inachis io, but very few satyrines such as the gatekeeper, Pyronia tithonus, which mostly visited Origanum. Eupatorium cannibinum had the highest Simpsonâs Diversity score of 0.75, while Buddleia and Origanum were lower, scoring 0.66 and 0.50 respectively. No one plant was good at attracting all observed butterfly species, as each attracted only a subset of the butterfly community. We conclude that to create a butterfly-friendly garden, a variety of plant species are required as nectar sources for butterflies. Furthermore, garden plant recommendations can probably benefit from being more precise as to the species of butterfly they attract
Study of relativistic nuclear collisions at AGS energies from p+Be to Au+Au with hadronic cascade model
A hadronic cascade model based on resonances and strings is used to study
mass dependence of relativistic nuclear collisions from p+Be to Au+Au at AGS
energies (\sim 10\AGeV) systematically. Hadron transverse momentum and
rapidity distributions obtained with both cascade calculations and Glauber type
calculations are compared with experimental data to perform detailed discussion
about the importance of rescattering among hadrons. We find good agreement with
the experimental data without any change of model parameters with the cascade
model. It is found that rescattering is of importance both for the explanation
of high transverse momentum tail and for the multiplicity of produced
particles.Comment: 27 pages, 30 figure
Quantum systems in weak gravitational fields
Fully covariant wave equations predict the existence of a class of
inertial-gravitational effects that can be tested experimentally. In these
equations inertia and gravity appear as external classical fields, but, by
conforming to general relativity, provide very valuable information on how
Einstein's views carry through in the world of the quantum.Comment: 22 pages. To be published in Proceedings of the 17th Course of the
International School of Cosmology and Gravitation "Advances in the interplay
between quantum and gravity physics" edited by V. De Sabbata and A.
Zheltukhin, Kluwer Academic Publishers, Dordrech
-scaling and Information Entropy in Ultra-Relativistic Nucleus-Nucleus Collisions
The -scaling method has been applied to ultra-relativistic p+p, C+C
and Pb+Pb collision data simulated using a high energy Monte Carlo package,
LUCIAE 3.0. The -scaling is found to be valid for some physical
variables, such as charged particle multiplicity, strange particle multiplicity
and number of binary nucleon-nucleon collisions from these simulated
nucleus-nucleus collisions over an extended energy ranging from = 20
to 200 A GeV. In addition we derived information entropy from the multiplicity
distribution as a function of beam energy for these collisions.Comment: 4 pages, 4 figures, 1 table; to appear in the July Issue of Chin.
Phys. Lett.. Web Page: http://www.iop.org/EJ/journal/CP
Arthroscopic Treatment of Acetabular Retroversion With Acetabuloplasty and Subspine Decompression: A Matched Comparison With Patients Undergoing Arthroscopic Treatment for Focal Pincer-Type Femoroacetabular Impingement.
BackgroundGlobal acetabular retroversion is classically treated with open reverse periacetabular osteotomy. Given the low morbidity and recent success associated with the arthroscopic treatment of femoroacetabular impingement (FAI), there may also be a role for arthroscopic treatment of acetabular retroversion. However, the safety and outcomes after hip arthroscopic surgery for retroversion need further study, and the effect of impingement from the anterior inferior iliac spine (subspine) in patients with retroversion is currently unknown.HypothesisArthroscopic treatment for global acetabular retroversion will be safe, and patients will have similar outcomes compared with a matched group undergoing arthroscopic treatment for focal pincer-type FAI.Study designCohort study; Level of evidence, 2.MethodsPatients undergoing hip arthroscopic surgery for symptomatic global acetabular retroversion were prospectively enrolled and compared with a matched group of patients undergoing arthroscopic surgery for focal pincer-type FAI. Both groups underwent the same arthroscopic treatment protocol. All patients were administered patient-reported outcome (PRO) measures, including the 12-item Short-Form Health Survey (SF-12) Physical Component Summary (PCS) and a Mental Component Summary (MCS), modified Harris Hip Score (mHHS), Hip disability and Osteoarthritis Outcome Score (HOOS), and visual analog scale (VAS) for pain preoperatively and at 1 year postoperatively.ResultsThere were no differences in age, sex, or body mass index between 39 hips treated for global acetabular retroversion and 39 hips treated for focal pincer-type FAI. There were no major or minor complications in either group. Patients who underwent arthroscopic treatment for global acetabular retroversion demonstrated similar significant improvements in postoperative PRO scores (scores increased by 17 to 43 points) as patients who underwent arthroscopic treatment for focal pincer-type FAI. Patients treated for retroversion who also underwent subspine decompression had greater improvement than patients who did not undergo subspine decompression for the HOOS-Pain (33.7 ± 15.3 vs 22.5 ± 17.6, respectively; P = .046) and HOOS-Quality of Life (49.7 ± 18.8 vs 34.6 ± 22.0, respectively; P = .030) scores.ConclusionArthroscopic treatment for acetabular retroversion is safe and provides significant clinical improvement similar to arthroscopic treatment for pincer-type FAI. Patients with acetabular retroversion who also underwent arthroscopic subspine decompression demonstrated greater improvements in pain and quality of life outcomes than those who underwent arthroscopic treatment without subspine decompression
Emerging Insights into Keratin 16 Expression during Metastatic Progression of Breast Cancer.
Keratins are the main identification markers of circulating tumor cells (CTCs); however, whether their deregulation is associated with the metastatic process is largely unknown. Previously we have shown by in silico analysis that keratin 16 (KRT16) mRNA upregulation might be associated with more aggressive cancer. Therefore, in this study, we investigated the biological role and the clinical relevance of K16 in metastatic breast cancer. By performing RT-qPCR, western blot, and immunocytochemistry, we investigated the expression patterns of K16 in metastatic breast cancer cell lines and evaluated the clinical relevance of K16 expression in CTCs of 20 metastatic breast cancer patients. High K16 protein expression was associated with an intermediate mesenchymal phenotype. Functional studies showed that K16 has a regulatory effect on EMT and overexpression of K16 significantly enhanced cell motility (p < 0.001). In metastatic breast cancer patients, 64.7% of the detected CTCs expressed K16, which was associated with shorter relapse-free survival (p = 0.0042). Our findings imply that K16 is a metastasis-associated protein that promotes EMT and acts as a positive regulator of cellular motility. Furthermore, determining K16 status in CTCs provides prognostic information that helps to identify patients whose tumors are more prone to metastasize
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