2,196 research outputs found
Method for High Accuracy Multiplicity Correlation Measurements
Multiplicity correlation measurements provide insight into the dynamics of
high energy collisions. Models describing these collisions need these
correlation measurements to tune the strengths of the underlying QCD processes
which influence all observables. Detectors, however, often possess limited
coverage or reduced efficiency that influence correlation measurements in
obscure ways. In this paper, the effects of non-uniform detection acceptance
and efficiency on the measurement of multiplicity correlations between two
distinct detector regions (termed forward-backward correlations) are derived.
An analysis method with such effects built-in is developed and subsequently
verified using different event generators. The resulting method accounts for
acceptance and efficiency in a model independent manner with high accuracy
thereby shedding light on the relative contributions of the underlying
processes to particle production.Comment: 28 pages, 13 figures. Updated for having pseudorapidity dependent
efficiency gradient
Why physicians are lousy gatekeepers: Sicklisting decisions when patients have private information on symptoms
In social insurance systems that grant workers paid sick leave, physicians act as gatekeepers, supposedly granting sickness certificates to the sick and not to shirkers. Previous research has emphasized the physician's superior ability to judge patients' need of treatment and potential collusion with the patient visâĂĄâvis an insurer. What is less well understood is the role of patients' private information. We explore the case where patients have private information about the presence of nonverifiable symptoms. Anyone can then claim to experience such symptoms, reducing physicians' ability to distinguish between sick patients and shirkers. Doubting a patients' reported symptoms may prevent good medical treatment of the truly sick. We show that for all parameter values, the Bayesian Nash equilibrium is that some physicians trust all claims of nonverifiable symptoms, sicklisting shirkers as well as sick; for many values, every physician is trusting. In particular, if physician strategies are observable by patients, extremely strong gatekeeping preferences are required to make physicians mistrust. To limit unwarranted sicklisting, policies reducing the benefits of shirking for healthy workers may be better suited than attempts to convince physicians to be strict.publishedVersio
Fibrations on four-folds with trivial canonical bundles
Four-folds with trivial canonical bundles are divided into six classes
according to their holonomy group. We consider examples that are fibred by
abelian surfaces over the projective plane. We construct such fibrations in
five of the six classes, and prove that there is no such fibration in the sixth
class. We classify all such fibrations whose generic fibre is the Jacobian of a
genus two curve.Comment: 28 page
Identifying gravity waves launched by the Hunga Tonga-Hunga Haâapai volcanic eruption in mesosphere/lower thermosphere winds derived from CONDOR and the Nordic Meteor Radar Cluster
The Hunga Tonga-Hunga Haâapai volcano eruption was a unique event that caused many atmospheric phenomena around the globe. In this study, we investigate the atmospheric gravity waves in the mesosphere/lower thermosphere (MLT) launched by the volcanic explosion in the Pacific leveraging multistatic meteor radar observations from the Chilean Observation Network De Meteor Radars (CONDOR) and the Nordic Meteor Radar Cluster in Fennoscandia. MLT winds are computed using a recently developed 3DVAR+DIV algorithm. We found an eastward and a westward traveling gravity wave in the CONDOR zonal and meridional wind measurements, which arrived 12 hours and 48 hours after the eruption, and one in Nordic Meteor Radar Cluster that arrived 27.5 hours after the volcanic detonation. We obtained observed phase speeds for the eastward great circle path at both locations of about 250 m/s and 170â150 m/s for the opposite propagation direction. The intrinsic phase speed was estimated to be 200â212 m/s. Furthermore, we identified a potential lamb wave signature in the MLT winds using 5 minute resolved 3DVAR+DIV retrievals
LIS1-leger og medisinsk usikkerhet â en kvalitativ studie
BAKGRUNN - Hvordan norske leger hÄndterer medisinsk usikkerhet, er lite studert. FormÄlet med studien var Ä undersÞke hvordan leger i spesialisering del 1 (LIS1-leger) opplever og hÄndterer usikkerhet i en klinisk hverdag.
MATERIALE OG METODER - Ti LIS1-leger ved to sykehus ble rekruttert til intervjuer etter svarmĂžnsteranalyse fra et kartleggende spĂžrreskjema. Intervjuene ble analysert med systematisk tekstkondensering.
RESULTATER - Analysen avdekket tre hovedtemaer i intervjuene: hÄndtering av medisinsk usikkerhet, personlig respons pÄ medisinsk usikkerhet samt arbeidsmiljÞ, tilbakemeldinger og forberedelse. Innen alle de tre tematiske omrÄdene brukte informantene ordene sikker/usikker og trygg/utrygg om hverandre.
FORTOLKNING - LIS1-legene strevde med medisinens iboende usikkerhet og kjente pÄ en betydelig utrygghet, spesielt i starten av tjenesten. Mottakelsen og tilbakemeldingene legene fikk pÄ arbeidsplassen var viktige. Den medisinske utdannelsen hadde i liten grad forberedt LIS1-legene pÄ mÞtet med medisinsk usikkerhet i en klinisk hverdag
Evidence of Final-State Suppression of High-p_T Hadrons in Au + Au Collisions Using d + Au Measurements at RHIC
Transverse momentum spectra of charged hadrons with 6 GeV/c have
been measured near mid-rapidity (0.2 1.4) by the PHOBOS experiment
at RHIC in Au + Au and d + Au collisions at . The spectra for different collision centralities are compared to collisions at the same energy. The resulting nuclear modification
factor for central Au + Au collisions shows evidence of strong suppression of
charged hadrons in the high- region ( GeV/c). In contrast, the d +
Au nuclear modification factor exhibits no suppression of the high-
yields. These measurements suggest a large energy loss of the high-
particles in the highly interacting medium created in the central Au + Au
collisions. The lack of suppression in d + Au collisions suggests that it is
unlikely that initial state effects can explain the suppression in the central
Au + Au collisions.Comment: 3 pages, 4 figures, International Europhysics Conference on High
Energy Physics EPS (July 17th-23rd 2003) in Aachen, German
Centrality dependence of charged antiparticle to particle ratios near mid-rapidity in d+Au collisions at sqrt(s_NN)=200 GeV
The ratios of the yields of charged antiparticles to particles have been
obtained for pions, kaons, and protons near mid-rapidity for d+Au collisions at
sqrt(s_NN) = 200 GeV as a function of centrality. The reported values represent
the ratio of the yields averaged over the rapidity range of 0.1<y_pi<1.3 and
0<y_(K,p)<0.8, where positive rapidity is in the deuteron direction, and for
transverse momenta 0.1<p_(T)^(pi,K)<1.0 GeV/c and 0.3<p_(T)^(p)<1.0 GeV/c.
Within the uncertainties, a lack of centrality dependence is observed in all
three ratios. The data are compared to results from other systems and model
calculations.Comment: 6 pages, 4 figures, submitted to PR
Centrality and pseudorapidity dependence of elliptic flow for charged hadrons in Au+Au collisions at sqrt(sNN) = 200 GeV
This paper describes the measurement of elliptic flow for charged particles
in Au+Au collisions at sqrt(sNN)=200 GeV using the PHOBOS detector at the
Relativistic Heavy Ion Collider (RHIC). The measured azimuthal anisotropy is
presented over a wide range of pseudorapidity for three broad collision
centrality classes for the first time at this energy. Two distinct methods of
extracting the flow signal were used in order to reduce systematic
uncertainties. The elliptic flow falls sharply with increasing eta at 200 GeV
for all the centralities studied, as observed for minimum-bias collisions at
sqrt(sNN)=130 GeV.Comment: Final published version: the most substantive change to the paper is
the inclusion of a complete description of how the errors from the hit-based
and track-based analyses are merged to produce the 90% C.L. errors quoted for
the combined results shown in Fig.
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