55 research outputs found
Central Pb+Pb Collisions at 158 A GeV/c Studied by Pion-Pion Interferometry
Two-particle correlations have been measured for identified negative pions
from central 158 AGeV Pb+Pb collisions and fitted radii of about 7 fm in all
dimensions have been obtained. A multi-dimensional study of the radii as a
function of kT is presented, including a full correction for the resolution
effects of the apparatus. The cross term Rout-long of the standard fit in the
Longitudinally CoMoving System (LCMS) and the vl parameter of the generalised
Yano-Koonin fit are compatible with 0, suggesting that the source undergoes a
boost invariant expansion. The shapes of the correlation functions in Qinv and
Qspace have been analyzed in detail. They are not Gaussian but better
represented by exponentials. As a consequence, fitting Gaussians to these
correlation functions may produce different radii depending on the acceptance
of the experimental setup used for the measurement.Comment: 13 pages including 10 figure
Search for Disoriented Chiral Condensates in 158 AGeV Pb+Pb Collisions
The restoration of chiral symmetry and its subsequent breaking through a
phase transition has been predicted to create regions of Disoriented Chiral
Condensates (DCC). This phenomenon has been predicted to cause anomalous
fluctuations in the relative production of charged and neutral pions in
high-energy hadronic and nuclear collisions. The WA98 experiment has been used
to measure charged and photon multiplicities in the central region of 158 AGeV
Pb+Pb collisions at the CERN SPS. In a sample of 212646 events, no clear DCC
signal can be distinguished. Using a simple DCC model, we have set a 90% C.L.
upper limit on the maximum DCC production allowed by the data.Comment: 20 Pages, LaTeX, uses elsart.cls, 8 eps figures included, submitted
to Physics Letters
Directed Flow in 158 A GeV + Collisions
The directed flow of protons and positive pions have been studied in 158 A GeV Pb + Pb collisions. A directed flow analysis of the rapidity dependence of the average transverse momentum projected onto the reaction plane is presented for semi-central collisions with impact parameters of approximately 8 fm, where the flow effect is largest. The magnitude of the directed flow is found to be significantly smaller than observed at AGS energies and than RQMD model predictions.The directed flow of protons and positive pions have been studied in 158 A GeV Pb + Pb collisions. A directed flow analysis of the rapidity dependence of the average transverse momentum projected onto the reaction plane is presented for semi-central collisions with impact parameters of approximately 8 fm, where the flow effect is largest. The magnitude of the directed flow is found to be significantly smaller than observed at AGS energies and than RQMD model predictions
Elliptic emission of K+ and pi(+) in 158 A center dot GeV Pb + Pb collisions
An event-by-event analysis of the azimuthal angular correlation with respect to the reaction plane has been carried out for K+ and pi(+) emission near mid-rapidity in 158 A . GeV Pb + Pb collisions. In semi-central collisions, K+ mesons are found to be preferentially emitted out of the reaction plane, while pi(+) mesons are emitted in the reaction plane. The results suggest that the kaon emission is influenced by in-medium potential effects in addition to collective flow effects. (C) 1999 Published by Elsevier Science B.V. All rights reserved
Delta(++) production in 158 A GeV Pb-208+Pb-208 interactions at the CERN SPS
The Delta(++)-resonance production in central 158 A GeV Pb-208 + Pb-208 collisions at the CERN SPS has been studied. The Delta(++) production was estimated from the invariant mass spectrum of p pi(+)-pairs by subtracting a mixed event background. The measured Delta(++) abundance is compared with the results from other experiments at lower energies, and with a model calculation assuming thermal and chemical equilibrium. (C) 2000 Elsevier Science B.V. All rights reserved
Research trends, challenges, and emerging topics in digital forensics: A review of reviews
Due to its critical role in cybersecurity, digital forensics has received significant attention from researchers and practitioners alike. The ever increasing sophistication of modern cyberattacks is directly related to the complexity of evidence acquisition, which often requires the use of several technologies. To date, researchers have presented many surveys and reviews on the field. However, such articles focused on the advances of each particular domain of digital forensics individually. Therefore, while each of these surveys facilitates researchers and practitioners to keep up with the latest advances in a particular domain of digital forensics, the global perspective is missing. Aiming to fill this gap, we performed a qualitative review of all the relevant reviews in the field of digital forensics, determined the main topics on digital forensics topics and identified their main challenges. Despite the diversity of topics and methods, there are several common problems that are faced by almost all of them, with most of them residing in evidence acquisition and pre-processing due to counter analysis methods and difficulties of collecting data from devices, the cloud etc. Beyond pure technical issues, our study highlights procedural issues in terms of readiness, reporting and presentation, as well as ethics, highlighting the European perspective which is traditionally stricter in terms of privacy. Our extensive analysis paves the way for closer collaboration among researcher and practitioners among different topics of digital forensics
Research trends, challenges, and emerging topics in digital forensics: A review of reviews
Due to its critical role in cybersecurity, digital forensics has received significant attention from researchers and practitioners alike. The ever increasing sophistication of modern cyberattacks is directly related to the complexity of evidence acquisition, which often requires the use of several technologies. To date, researchers have presented many surveys and reviews on the field. However, such articles focused on the advances of each particular domain of digital forensics individually. Therefore, while each of these surveys facilitates researchers and practitioners to keep up with the latest advances in a particular domain of digital forensics, the global perspective is missing. Aiming to fill this gap, we performed a qualitative review of all the relevant reviews in the field of digital forensics, determined the main topics on digital forensics topics and identified their main challenges. Despite the diversity of topics and methods, there are several common problems that are faced by almost all of them, with most of them residing in evidence acquisition and pre-processing due to counter analysis methods and difficulties of collecting data from devices, the cloud etc. Beyond pure technical issues, our study highlights procedural issues in terms of readiness, reporting and presentation, as well as ethics, highlighting the European perspective which is traditionally stricter in terms of privacy. Our extensive analysis paves the way for closer collaboration among researcher and practitioners among different topics of digital forensics.Cyber Securit
Association of PPAR polymorphisms with cytokine levels in allergic rhinitis
Our aim was to study the association of Pro12Ala and exon6 C161T polymorphisms of PPARgamma and intron7 G/C polymorphisms of PPAR-alpha with clinical symptoms, peak nasal inspiratory flow values, serum soluble TNF-alpha, TNF-R1, Fas, Fas ligand and IgE concentrations in patients with seasonal allergic rhinitis during and after pollen season. We performed a follow-up study of 66 Hungarian patients with seasonal allergic rhinitis and 180 healthy referent subjects. We used PCR-RFLP technique and ELISA. The distribution of mutant alleles of PPAR-gamma and -alpha did not differ in patients and referent subjects. Patients carrying the mutant 12Ala, exon6 161T alleles of PPAR-gamma and intron7 C allele of PPAR-alpha had significantly higher clinical symptom score values, TNF-alpha and IgE levels and lower peak nasal inspiratory flow values during and after pollen season. The results indicated that nuclear receptors PPAR-gamma and PPAR-alpha are involved in the regulation of inflammatory mediator production in patients with seasonal allergic rhinitis and polymorphisms of the receptors are very likely to contribute to the heterogeneity of clinical and immunological parameters of allergic patients. © 2011 Springer-Verlag
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