986 research outputs found
The statistical hadronization model approach to GeV Au-Au collisions: -spectra fits and global variable predictions
Three possible scenarios of the statistical hadronization model are
reexamined with the use of the spectra of the PHENIX and very low
PHOBOS measurements at GeV. These scenarios are:
(\textit{a}) full chemical non-equilibrium, (\textit{b}) strangeness chemical
non-equilibrium and (\textit{c}) chemical equilibrium. Fits to the spectra are
done within the Cracow single-freeze-out model, which takes into account both
the expansion and resonance decays. Predictions for spectra of ,
and are also given. The global variables like the
transverse energy at midrapidity, the charged particle multiplicity at
midrapidity and the total multiplicity of charged particles are evaluated and
their predicted values agree qualitatively well with the experimental data. The
thorough analysis within this model suggests that the chemical full
non-equilibrium case is the least likely and both other cases are of the
similar likelihood. It is also shown that if the full chemical non-equilibrium
freeze-out took place it could manifest itself in the enhancement of the
-production at very low transverse momenta.Comment: 19 pages, 16 figures (included). This is the final version accepted
in Phys. Rev. C. Figs.9 and 10 have been changed since it turned out that the
data on \phi meson production were corrected for the branching ratio of \phi
decay into K_{+}K_{-
Centrality dependence of global variables in relativistic heavy ion collisions: Final data analysis in the framework of a statistical model
The global variables like the transverse energy at midrapidity, the charged
particle multiplicity at midrapidity and the total multiplicity of charged
particles are evaluated in the single-freeze-out statistical model for
different centrality bins at RHIC at and 200 GeV. Full
description of decays of hadron resonances is applied in these estimations. The
geometric parameters of the model are obtained from the fit to the final data
on the spectra. The predicted values of the global variables agree
qualitatively well with the experimental data. The centrality independence of
the total number of charged particles per participant pair has been also
reproduced.Comment: Revtex, 12 figures (included), 16 pages. This is the revised final
version accepted for publication in Physical Review C. The main difference
with the first version is that the geometric parameters of the model have
been fitted again with the use of the newer estimates of the statistical
parameters reported in Refs. [20,21] for the case of GeV.
Also because of the editorial reasons the title has been slightly change
High-accuracy numerical integration methods for fractional order derivatives and integrals computations
In this paper the authors present highly accurate and remarkably efficient computational methods for fractional order derivatives and integrals applying Riemann-Liouville and Caputo formulae: the Gauss-Jacobi Quadrature with adopted weight function, the Double Exponential Formula, applying two arbitrary precision and exact rounding mathematical libraries (GNU GMP and GNU MPFR). Example fractional order derivatives and integrals of some elementary functions are calculated. Resulting accuracy is compared with accuracy achieved by applying widely known methods of numerical integration. Finally, presented methods are applied to solve Abelâs Integral equation (in Appendix)
Wigner function and Schroedinger equation in phase space representation
We discuss a family of quasi-distributions (s-ordered Wigner functions of
Agarwal and Wolf) and its connection to the so called phase space
representation of the Schroedinger equation. It turns out that although Wigner
functions satisfy the Schroedinger equation in phase space they have completely
different interpretation.Comment: 6 page
Quantum Mechanics of Damped Systems II. Damping and Parabolic Potential Barrier
We investigate the resonant states for the parabolic potential barrier known
also as inverted or reversed oscillator. They correspond to the poles of
meromorphic continuation of the resolvent operator to the complex energy plane.
As a byproduct we establish an interesting relation between parabolic cylinder
functions (representing energy eigenfunctions of our system) and a class of
Gel'fand distributions used in our recent paper.Comment: 14 page
Optimal time of duration of a long-term video-EEG monitoring in paroxysmal events â A retrospective analysis of 282 sessions in 202 patients
Purpose
To find the optimal duration of the long-term video-EEG (LTM) and assess diagnostics utility of LTM in patients with epilepsy and other paroxysmal events in terms of future diagnosis and management.
Methods
Retrospective analysis of 282 LTMs performed in the last 5 years in our Epilepsy Monitoring Unit (EMU), in 202 consecutive patients. The analysis included demographic data, monitoring time, number and type of paroxysmal events, the time until their onset, influence of LTM result on the diagnosis and future management.
Results
There were 117 women and 85 men, mean age 34.2 years. Mean duration of LTM was 5 days (3â9), with 447 paroxysmal events recorded in 131 (65%) patients. Epileptic seizures were recorded in 82% cases (in 11% associated with PNES). The remaining 18% had either PNES (psychogenic non-epileptic seizures) â 11%, or parasomnias â 7%. Only 15% of epileptic seizures took place within the first 24h of the LTM (53% and 32% on the 2nd and 3rd day, respectively), whereas as many as 62% of PNES did (while only 28% and 10% on the 2nd and 3rd day, respectively). The LTM results changed the diagnosis in 36% of the patients, most frequently in PNES (from 2% to 14%). Altogether, it changed the management in 64% of the patients â particularly with PNES and those who underwent epilepsy surgery.
Conclusions
LTM should last at least 72h in patients with refractory epilepsy. Most of cases with PNES could be diagnosed after 48h
Diversity, genetic mapping, and signatures of domestication in the carrot (Daucus carota L.) genome, as revealed by Diversity Arrays Technology (DArT) markers
Carrot is one of the most economically important vegetables worldwide, but genetic and genomic resources supporting carrot breeding remain limited. We developed a Diversity Arrays Technology (DArT) platform for wild and cultivated carrot and used it to investigate genetic diversity and to develop a saturated genetic linkage map of carrot. We analyzed a set of 900 DArT markers in a collection of plant materials comprising 94 cultivated and 65 wild carrot accessions. The accessions were attributed to three separate groups: wild, Eastern cultivated and Western cultivated. Twenty-seven markers showing signatures for selection were identified. They showed a directional shift in frequency from the wild to the cultivated, likely reflecting diversifying selection imposed in the course of domestication. A genetic linkage map constructed using 188 F2 plants comprised 431 markers with an average distance of 1.1 cM, divided into nine linkage groups. Using previously anchored single nucleotide polymorphisms, the linkage groups were physically attributed to the nine carrot chromosomes. A cluster of markers mapping to chromosome 8 showed significant segregation distortion. Two of the 27 DArT markers with signatures for selection were segregating in the mapping population and were localized on chromosomes 2 and 6. Chromosome 2 was previously shown to carry the Vrn1 gene governing the biennial growth habit essential for cultivated carrot. The results reported here provide background for further research on the history of carrot domestication and identify genomic regions potentially important for modern carrot breeding
Optical modeling of ocean waters: Is the case 1 - case 2 classification still useful?
âŠtwo extreme cases can be identified and separated. Case 1 is that of a concentration of phytoplankton high compared to other particlesâŠ. In contrast, the inorganic particles are dominant in case 2.⊠In both cases dissolved yellow substance is present in variable amounts.⊠An ideal case 1 would be a pure culture of phytoplankton and an ideal case 2 a suspension of nonliving material with a zero concentration of pigments.
Morel and Prieur emphasized that these ideal cases are not encountered in nature, and they suggested the use of high or low values of the ratio of pigment concentration to scattering coefficient as a basis for discriminating between Case 1 and Case 2 waters. Although no specific values of this ratio were proposed to serve as criteria for classification, their example data suggested that the ratio of chlorophyll a concentration (in mg m-3) to the scattering coefficient at 550 nm (in m-1) in Case 1 waters is greater than 1 and in Case 2 waters is less than 1. Importantly, however, Morel and Prieur also showed data classified as âintermediate watersâ with the ratio between about 1 and 2.2.
Although the original definition from 1977 did not imply a binary classification, the practice of most investigators in the following years clearly evolved toward a bipartite analysis
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