1,038 research outputs found
From mental disorder to shared understanding: a non-categorical approach to support individuals with distress in primary care.
The electoral geography of provisional ballot in North Carolina by county: 2008 U.S. Presidential election
The geography of provisional ballots is a realm of electoral geography that is increasingly important as a key component of shaping election outcomes, yet has been considerably under-researched. This purpose of this dissertation is to identify the geographic significance and the overall impact of the 52,000 provisional ballots cast during the 2008 Presidential election in North Carolina as well as conduct the first comprehensive analysis of the spatial distribution of provisional ballots in North Carolina in both absolute and relative terms during the 2008 Presidential Election. The first phase of the research conducted an inventory of the geography of absolute provisional ballots whereas the second phase of the research used stepwise multiple regression modeling to highlight the links that existed between three dependent variables; provisional ballots cast, ineligible provisional ballots and eligible provisional ballots and a number of independent predictor variables (e.g. race, age, education, etc.). The research found that counties with older, more educated, white populations with traditional political ideologies cast provisional ballots at a lower rate and have their provisional ballots deemed eligible at a lower rate than other counties. Finally, counties with larger minority populations, specifically Native Americans, and younger populations appear to cast provisional ballots and have those ballots counted at a higher rate than other counties less diverse older populations
Measurements of two-particle correlations in collisions at 91 GeV with ALEPH archived data
Measurements of two-particle angular correlations of charged particles
emitted in hadronic decays are presented. The archived
annihilation data at a center-of-mass energy of 91 GeV were collected with the
ALEPH detector at LEP between 1992 and 1995. The correlation functions are
measured over a broad range of pseudorapidity and full azimuth as a function of
charged particle multiplicity. No significant long-range correlation is
observed in either the lab coordinate analysis or the thrust coordinate
analysis, where the latter is sensitive to a medium expanding transverse to the
color string between the outgoing pair from boson decays. The
associated yield distributions in both analyses are in better agreement with
the prediction from the PYTHIA v6.1 event generator than from HERWIG v7.1.5.
They provide new insights to showering and hadronization modeling. These
results serve as an important reference to the observed long-range correlation
in proton-proton, proton-nucleus, and nucleus-nucleus collisions.Comment: Replaced with the published version. Added the journal reference and
the DO
First measurement of anti-k jet spectra and jet substructure using the archived ALEPH data at 91.2 GeV
We present the first anti-k jet spectrum and substructure measurements
using the archived ALEPH data taken in 1994 at a center of mass energy
of GeV. Jets are reconstructed with the anti-k
algorithm with a resolution parameter of 0.4. It is the cleanest test of jets
and QCD without the complication of hadronic initial states. The fixed
center-of-mass energy also allows the first direct test of pQCD calculation. We
present both the inclusive jet energy spectrum and the leading dijet energy
spectra, together with a number of substructure observables. They are compared
to predictions from PYTHIA6, PYTHIA8, Sherpa, HERWIG, VINCIA, and PYQUEN. None
of the models fully reproduce the data. The data are also compared to two
perturbative QCD calculations at NLO and with NLL'+R resummation. The results
can also serve as reference measurements to compare to results from hadronic
colliders. Future directions, including testing jet clustering algorithms
designed for future electron-ion collider experiments, will also be discussed
The nuclear star cluster of the Milky Way: proper motions and mass
Nuclear star clusters (NSCs) are located at the photometric and dynamical
centers of the majority of galaxies. They are among the densest star clusters
in the Universe. The NSC in the Milky Way is the only object of this class that
can be resolved into individual stars. We measured the proper motions of more
than 6000 stars within ~1.0 pc of the supermassive black hole Sgr A*. The full
data set is provided in this work. We largely exclude the known early-type
stars with their peculiar dynamical properties from the dynamical analysis. The
cluster is found to rotate parallel to Galactic rotation, while the velocity
dispersion appears isotropic (or anisotropy may be masked by the cluster
rotation). The Keplerian fall-off of the velocity dispersion due to the point
mass of Sgr A* is clearly detectable only at R <~ 0.3 pc. Nonparametric
isotropic and anisotropic Jeans models are applied to the data. They imply a
best-fit black hole mass of 3.6 (+0.2/-0.4) x 10^6 solar masses. Although this
value is slightly lower than the current canonical value of 4.0x10^6 solar
masses, this is the first time that a proper motion analysis provides a mass
for Sagittarius A* that is consistent with the mass inferred from orbits of
individual stars. The point mass of Sagittarius A* is not sufficient to explain
the velocity data. In addition to the black hole, the models require the
presence of an extended mass of 0.5-1.5x10^6 solar masses in the central
parsec. This is the first time that the extended mass of the nuclear star
cluster is unambiguously detected. The influence of the extended mass on the
gravitational potential becomes notable at distances >~0.4 pc from Sgr A*.
Constraints on the distribution of this extended mass are weak. The extended
mass can be explained well by the mass of the stars that make up the cluster.Comment: accepted for publication in Astronomy & Astrophysics; please contact
first author for higher quality figure
Star Formation and Dynamics in the Galactic Centre
The centre of our Galaxy is one of the most studied and yet enigmatic places
in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre
(GC) is the ideal environment to study the extreme processes that take place in
the vicinity of a supermassive black hole (SMBH). Despite the hostile
environment, several tens of early-type stars populate the central parsec of
our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and
inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the
SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The
formation of such early-type stars has been a puzzle for a long time: molecular
clouds should be tidally disrupted by the SMBH before they can fragment into
stars. We review the main scenarios proposed to explain the formation and the
dynamical evolution of the early-type stars in the GC. In particular, we
discuss the most popular in situ scenarios (accretion disc fragmentation and
molecular cloud disruption) and migration scenarios (star cluster inspiral and
Hills mechanism). We focus on the most pressing challenges that must be faced
to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in
expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A.,
'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201
Search for third-generation scalar leptoquarks in the tÏ channel in proton-proton collisions at âs = 8 TeV
A search for pair production of third-generation scalar leptoquarks decaying to top quark and Ï lepton pairs is presented using proton-proton collision data at a center-of-mass energy of âs = 8 TeV collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7 fb[superscript â1]. The search is performed using events that contain an electron or a muon, a hadronically decaying Ï lepton, and two or more jets. The observations are found to be consistent with the standard model predictions. Assuming that all leptoquarks decay to a top quark and a Ï lepton, the existence of pair produced, charge â1/3, third-generation leptoquarks up to a mass of 685 GeV is excluded at 95% confidence level. This result constitutes the first direct limit for leptoquarks decaying into a top quark and a Ï lepton, and may also be applied directly to the pair production of bottom squarks decaying predominantly via the R-parity violating coupling λ [subscript 333] âČ.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
Search for Pair-Produced Resonances Decaying to Quark Pairs in Proton-Proton Collisions at âs = 13ââTeV
A general search for the pair production of resonances, each decaying to two quarks, is reported. The search is conducted separately for heavier resonances (masses above 400 GeV), where each of the four final-state quarks generates a hadronic jet resulting in a four-jet signature, and for lighter resonances (masses between 80 and 400 GeV), where the pair of quarks from each resonance is collimated and reconstructed as a single jet resulting in a two-jet signature. In addition, a b-tagged selection is applied to target resonances with a bottom quark in the final state. The analysis uses data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 35.9ââfbâ»Âč, from proton-proton collisions at a center-of-mass energy of 13 TeV. The mass spectra are analyzed for the presence of new resonances, and are found to be consistent with standard model expectations. The results are interpreted in the framework of R-parity-violating supersymmetry assuming the pair production of scalar top quarks decaying via the hadronic coupling λâČâČ312 or λâČâČ323 and upper limits on the cross section as a function of the top squark mass are set. These results probe a wider range of masses than previously explored at the LHC, and extend the top squark mass limits in the ËtâqqâČ scenario
Search for electroweak production of charginos and neutralinos in multilepton final states in proton-proton collisions at âs = 13 TeV
Results are presented from a search for the direct electroweak production of charginos and neutralinos in signatures with either two or more leptons (electrons or muons) of the same electric charge, or with three or more leptons, which can include up to two hadronically decaying tau leptons. The results are based on a sample of proton-proton collision data collected at sâ=13 TeV, recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fbâ»Âč. The observed event yields are consistent with the expectations based on the standard model. The results are interpreted in simplified models of supersymmetry describing various scenarios for the production and decay of charginos and neutralinos. Depending on the model parameters chosen, mass values between 180 GeV and 1150 GeV are excluded at 95% CL. These results significantly extend the parameter space probed for these particles in searches at the LHC. In addition, results are presented in a form suitable for alternative theoretical interpretations
Search for Standard Model Production of Four Top Quarks with Same-Sign and Multilepton Final States in Protonâproton Collisions at âs = 13 TeV
A search for standard model production of four top quarks (ttÂŻttÂŻ) is reported using events containing at least three leptons (e,ÎŒ) or a same-sign lepton pair. The events are produced in protonâproton collisions at a center-of-mass energy of 13TeV at the LHC, and the data sample, recorded in 2016, corresponds to an integrated luminosity of 35.9fb[superscript â1]. Jet multiplicity and flavor are used to enhance signal sensitivity, and dedicated control regions are used to constrain the dominant backgrounds. The observed and expected signal significances are, respectively, 1.6 and 1.0 standard deviations, and the ttÂŻttÂŻ cross section is measured to be 16.9[superscript +13.8][subscript â11.4] fb, in agreement with next-to-leading-order standard model predictions. These results are also used to constrain the Yukawa coupling between the top quark and the Higgs boson to be less than 2.1 times its expected standard model value at 95% confidence level
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