148 research outputs found
Local structure of REFeAsO (RE=La, Pr, Nd, Sm) oxypnictides studied by Fe K-edge EXAFS
Local structure of REOFeAs (RE=La, Pr, Nd, Sm) system has been studied as a
function of chemical pressure varied due to different rare-earth size. Fe
K-edge extended X-ray absorption fine structure (EXAFS) measurements in the
fluorescence mode has permitted to compare systematically the inter-atomic
distances and their mean square relative displacements (MSRD). We find that the
Fe-As bond length and the corresponding MSRD hardly show any change, suggesting
the strongly covalent nature of this bond, while the Fe-Fe and Fe-RE bond
lengths decrease with decreasing rare earth size. The results provide important
information on the atomic correlations that could have direct implication on
the superconductivity and magnetism of REOFeAs system, with the chemical
pressure being a key ingredient
Forensic Investigation of Cyberstalking Cases using Behavioural Evidence Analysis
Behavioural Evidence Analysis (BEA) is, in theory, useful in developing an understanding of the offender, the victim, the crime scene, and the dynamics of the crime. It can add meaning to the evidence obtained through digital forensic techniques and assist investigators with reconstruction of a crime. There is, however, little empirical research examining the application of BEA to actual criminal cases, particularly cyberstalking cases. This study addresses this gap by examining the utility of BEA for such cases in terms of understanding the behavioural and motivational dimensions of offending, and the way in which digital evidence can be interpreted. It reports on the forensic analysis of 20 cyberstalking cases investigated by Dubai Police in the last five years. Results showed that BEA helps to focus an investigation, enables better understanding and interpretation of victim and offender behaviour, and assists in inferring traits of the offender from available digital evidence. These benefits can help investigators to build a stronger case, reduce time wasted to mistakes, and to exclude suspects wrongly accused in cyberstalking cases
Sociodemographic and clinical characteristics of the first cohort of COVID-19 recoveries at two national treatment centres in Accra, Ghana
Introduction COVID-19 is a new disease, knowledge on the mode of transmission and clinical features are still evolving, new tests are being developed with inherent challenges regarding interpretation of tests results. There is generally, a gap in knowledge on the virus globally as the pandemic evolves and in Ghana, there is dearth of information and documentation on the clinical characteristics of the virus. With these in mind, we set out to profile the initial cohort of COVID-19 patients who recovered in Ghana.
Methods: We reviewed clinical records of all confirmed cases of COVID-19 who had recovered from the two main treatment centres in Accra, Ghana. Descriptive data analysis was employed and presented in simple and relational tables. Independent t-test and ANOVA were used to determine differences in the mean age of the sexes and the number of days taken for the first and second retesting to be done per selected patient characteristics.
Results: Of the 146 records reviewed, 54% were male; mean age of patients was 41.9 ± 17.5 years, nearly half were asymptomatic, with 9% being severely ill. The commonest presenting symptoms were cough (22.6%), headache (13%) and sore throat (11%) while the commonest co-morbidities were hypertension (25.3%), diabetes mellitus (14%) and heart disease (3.4%).
Conclusion: COVID-19 affected more males than females; nearly half of those infected were asymptomatic. Cough, headache and sore throat were the commonest symptoms and mean duration from case confirmation to full recovery was 19 days. Further research is required as pandemic evolve
Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV
We report a measurement of the longitudinal double-spin asymmetry A_LL and
the differential cross section for inclusive Pi0 production at midrapidity in
polarized proton collisions at sqrt(s) = 200 GeV. The cross section was
measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be
in good agreement with a next-to-leading order perturbative QCD calculation.
The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T <
11 GeV/c and excludes a maximal positive gluon polarization in the proton. The
mean transverse momentum fraction of Pi0's in their parent jets was found to be
around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC
Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at GeV
We present first measurements of the evolution of the differential transverse
momentum correlation function, {\it C}, with collision centrality in Au+Au
interactions at GeV. {\it C} exhibits a strong dependence
on collision centrality that is qualitatively similar to that of number
correlations previously reported. We use the observed longitudinal broadening
of the near-side peak of {\it C} with increasing centrality to estimate the
ratio of the shear viscosity to entropy density, , of the matter formed
in central Au+Au interactions. We obtain an upper limit estimate of
that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.
High non-photonic electron production in + collisions at = 200 GeV
We present the measurement of non-photonic electron production at high
transverse momentum ( 2.5 GeV/) in + collisions at
= 200 GeV using data recorded during 2005 and 2008 by the STAR
experiment at the Relativistic Heavy Ion Collider (RHIC). The measured
cross-sections from the two runs are consistent with each other despite a large
difference in photonic background levels due to different detector
configurations. We compare the measured non-photonic electron cross-sections
with previously published RHIC data and pQCD calculations. Using the relative
contributions of B and D mesons to non-photonic electrons, we determine the
integrated cross sections of electrons () at 3 GeV/10 GeV/ from bottom and charm meson decays to be = 4.0({\rm
stat.})({\rm syst.}) nb and =
6.2({\rm stat.})({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure
Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV
We present measurements of the charge balance function, from the charged
particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au
collisions at 200 GeV using the STAR detector at RHIC. We observe that the
balance function is boost-invariant within the pseudorapidity coverage [-1.3,
1.3]. The balance function properly scaled by the width of the observed
pseudorapidity window does not depend on the position or size of the
pseudorapidity window. This scaling property also holds for particles in
different transverse momentum ranges. In addition, we find that the width of
the balance function decreases monotonically with increasing transverse
momentum for all centrality classes.Comment: 6 pages, 3 figure
Energy and system size dependence of \phi meson production in Cu+Cu and Au+Au collisions
We study the beam-energy and system-size dependence of \phi meson production
(using the hadronic decay mode \phi -- K+K-) by comparing the new results from
Cu+Cu collisions and previously reported Au+Au collisions at \sqrt{s_NN} = 62.4
and 200 GeV measured in the STAR experiment at RHIC. Data presented are from
mid-rapidity (|y|<0.5) for 0.4 < pT < 5 GeV/c. At a given beam energy, the
transverse momentum distributions for \phi mesons are observed to be similar in
yield and shape for Cu+Cu and Au+Au colliding systems with similar average
numbers of participating nucleons. The \phi meson yields in nucleus-nucleus
collisions, normalised by the average number of participating nucleons, are
found to be enhanced relative to those from p+p collisions with a different
trend compared to strange baryons. The enhancement for \phi mesons is observed
to be higher at \sqrt{s_NN} = 200 GeV compared to 62.4 GeV. These observations
for the produced \phi(s\bar{s}) mesons clearly suggest that, at these collision
energies, the source of enhancement of strange hadrons is related to the
formation of a dense partonic medium in high energy nucleus-nucleus collisions
and cannot be alone due to canonical suppression of their production in smaller
systems.Comment: 20 pages and 5 figure
Measurement of the Bottom contribution to non-photonic electron production in collisions at =200 GeV
The contribution of meson decays to non-photonic electrons, which are
mainly produced by the semi-leptonic decays of heavy flavor mesons, in
collisions at 200 GeV has been measured using azimuthal
correlations between non-photonic electrons and hadrons. The extracted
decay contribution is approximately 50% at a transverse momentum of GeV/. These measurements constrain the nuclear modification factor for
electrons from and meson decays. The result indicates that meson
production in heavy ion collisions is also suppressed at high .Comment: 6 pages, 4 figures, accepted by PR
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