607 research outputs found
On the Four Types of Weight Functions for Spatial Contiguity Matrix
This is a "spatial autocorrelation analysis" of spatial autocorrelation. I
use the 1-dimension spatial autocorrelation function (ACF) and partial
autocorrelation function (PACF) to analyze four kinds of weight function in
common use for the 2-dimensional spatial autocorrelation model. The aim of this
study is at how to select a proper weight function to construct a spatial
contiguity matrix for spatial analysis. The scopes of application of different
weight functions are defined in terms of the characters of their ACFs and
PACFs.Comment: 8 pages, 5 figures, 2 table
Complex differences in infection rates between ethnic groups in Scotland: a retrospective, national census-linked cohort study of 1.65 million cases
Background Ethnicity can influence susceptibility to infection, as COVID-19 has shown. Few countries have systematically investigated ethnic variations in infection. Methods We linked the Scotland 2001 Census, including ethnic group, to national databases of hospitalizations/deaths and serological diagnoses of bloodborne viruses for 2001â2013. We calculated age-adjusted rate ratios (RRs) in 12 ethnic groups for all infections combined, 15 infection categories, and human immunodeficiency virus (HIV), hepatitis B (HBV) and hepatitis C (HCV) viruses. Results We analysed over 1.65 million infection-related hospitalisations/deaths. Compared with White Scottish, RRs for all infections combined were 0.8 or lower for Other White British, Other White and Chinese males and females, and 1.2â1.4 for Pakistani and African males and females. Adjustment for socioeconomic status or birthplace had little effect. RRs for specific infection categories followed similar patterns with striking exceptions. For HIV, RRs were 136 in African females and 14 in males; for HBV, 125 in Chinese females and 59 in males, 55 in African females and 24 in males; and for HCV, 2.3â3.1 in Pakistanis and Africans. Conclusions Ethnic differences were found in overall rates and many infection categories, suggesting multiple causative pathways. We recommend census linkage as a powerful method for studying the disproportionate impact of COVID-19
New exact solution of Dirac-Coulomb equation with exact boundary condition
It usually writes the boundary condition of the wave equation in the Coulomb
field as a rough form without considering the size of the atomic nucleus. The
rough expression brings on that the solutions of the Klein-Gordon equation and
the Dirac equation with the Coulomb potential are divergent at the origin of
the coordinates, also the virtual energies, when the nuclear charges number Z >
137, meaning the original solutions do not satisfy the conditions for
determining solution. Any divergences of the wave functions also imply that the
probability density of the meson or the electron would rapidly increase when
they are closing to the atomic nucleus. What it predicts is not a truth that
the atom in ground state would rapidly collapse to the neutron-like. We
consider that the atomic nucleus has definite radius and write the exact
boundary condition for the hydrogen and hydrogen-like atom, then newly solve
the radial Dirac-Coulomb equation and obtain a new exact solution without any
mathematical and physical difficulties. Unexpectedly, the K value constructed
by Dirac is naturally written in the barrier width or the equivalent radius of
the atomic nucleus in solving the Dirac equation with the exact boundary
condition, and it is independent of the quantum energy. Without any divergent
wave function and the virtual energies, we obtain a new formula of the energy
levels that is different from the Dirac formula of the energy levels in the
Coulomb field.Comment: 12 pages,no figure
The T2K ND280 Off-Axis Pi-Zero Detector
The Pi-Zero detector (P{\O}D) is one of the subdetectors that makes up the
off-axis near detector for the Tokai-to-Kamioka (T2K) long baseline neutrino
experiment. The primary goal for the P{\O}D is to measure the relevant cross
sections for neutrino interactions that generate pi-zero's, especially the
cross section for neutral current pi-zero interactions, which are one of the
dominant sources of background to the electron neutrino appearance signal in
T2K. The P{\O}D is composed of layers of plastic scintillator alternating with
water bags and brass sheets or lead sheets and is one of the first detectors to
use Multi-Pixel Photon Counters (MPPCs) on a large scale.Comment: 17 pages, submitted to NIM
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
Measurements of long-range near-side angular correlations in TeV proton-lead collisions in the forward region
Two-particle angular correlations are studied in proton-lead collisions at a
nucleon-nucleon centre-of-mass energy of TeV, collected
with the LHCb detector at the LHC. The analysis is based on data recorded in
two beam configurations, in which either the direction of the proton or that of
the lead ion is analysed. The correlations are measured in the laboratory
system as a function of relative pseudorapidity, , and relative
azimuthal angle, , for events in different classes of event
activity and for different bins of particle transverse momentum. In
high-activity events a long-range correlation on the near side, , is observed in the pseudorapidity range . This
measurement of long-range correlations on the near side in proton-lead
collisions extends previous observations into the forward region up to
. The correlation increases with growing event activity and is found
to be more pronounced in the direction of the lead beam. However, the
correlation in the direction of the lead and proton beams are found to be
compatible when comparing events with similar absolute activity in the
direction analysed.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-040.htm
Evidence for the strangeness-changing weak decay
Using a collision data sample corresponding to an integrated luminosity
of 3.0~fb, collected by the LHCb detector, we present the first search
for the strangeness-changing weak decay . No
hadron decay of this type has been seen before. A signal for this decay,
corresponding to a significance of 3.2 standard deviations, is reported. The
relative rate is measured to be
, where and
are the and fragmentation
fractions, and is the branching
fraction. Assuming is bounded between 0.1 and
0.3, the branching fraction would lie
in the range from to .Comment: 7 pages, 2 figures, All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-047.htm
Study of the production of and hadrons in collisions and first measurement of the branching fraction
The product of the () differential production
cross-section and the branching fraction of the decay () is
measured as a function of the beauty hadron transverse momentum, ,
and rapidity, . The kinematic region of the measurements is and . The measurements use a data sample
corresponding to an integrated luminosity of collected by the
LHCb detector in collisions at centre-of-mass energies in 2011 and in 2012. Based on previous LHCb
results of the fragmentation fraction ratio, , the
branching fraction of the decay is
measured to be \begin{equation*} \mathcal{B}(\Lambda_b^0\rightarrow J/\psi
pK^-)= (3.17\pm0.04\pm0.07\pm0.34^{+0.45}_{-0.28})\times10^{-4},
\end{equation*} where the first uncertainty is statistical, the second is
systematic, the third is due to the uncertainty on the branching fraction of
the decay , and the
fourth is due to the knowledge of . The sum of the
asymmetries in the production and decay between and
is also measured as a function of and .
The previously published branching fraction of , relative to that of , is updated.
The branching fractions of are determined.Comment: 29 pages, 19figures. All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-032.htm
flavour tagging using charm decays at the LHCb experiment
An algorithm is described for tagging the flavour content at production of
neutral mesons in the LHCb experiment. The algorithm exploits the
correlation of the flavour of a meson with the charge of a reconstructed
secondary charm hadron from the decay of the other hadron produced in the
proton-proton collision. Charm hadron candidates are identified in a number of
fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is
calibrated on the self-tagged decay modes and using of data collected by the LHCb
experiment at centre-of-mass energies of and
. Its tagging power on these samples of
decays is .Comment: All figures and tables, along with any supplementary material and
additional information, are available at
http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in âs = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fbâ1 of protonâproton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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