1,140 research outputs found
Somatic disorders and antidepressant use in suicides: A population-based study from the Friuli Venezia Giulia region, Italy, 2003-2013
Background: Many somatic disorders are complicated by depression and increase the risk of suicide. Little is
known about whether antidepressants might reduce the suicidal risk in patients with somatic disorders.
Methods: Data on diagnoses and antidepressant prescriptions were derived from the Social and Health
Information System of the Friuli Venezia Giulia Region. Cases were all suicides that occurred in the region during
the years 2003\u20132013 and were sex- and age-matched to controls from the general population. Conditional
logistic regression analysis was used to assess the association between suicide and somatic disorders.
Results: The suicide rate in Friuli Venezia Giulia decreased from 11.3 to 10.7 per 100,000 inhabitants during the
years 2003\u20132013, however patients with somatic disorder had a three times increased risk of suicide. Elderly
somatic patients' suicide risk was twice as high as younger patients. The risk increased from 2.6 to 9.8 times as
the number of comorbid disorders increased from 1 to 4 and over. Although no significant risk of suicide in
patients with somatic disorders was found when patients were adherent to antidepressants, only 11.5% of the
suicides was adherent in the year prior to death.
Conclusions: Medical illnesses and underlying depressive symptoms may have a synergy effect on the risk of
suicide, particularly in older patients and in patients with multiple morbidities. Since medically ill subjects
adherent to antidepressants did not showa significant risk of suicide, early identification and adequate treatment
of depression in somatic patients should be considered in order to prevent suicide
Discrete interactions between a few interlayer excitons trapped at a MoSe<sub>2</sub>âWSe<sub>2</sub> heterointerface
Interlayer excitons (IXs) in hetero-bilayers of transition metal
dichalcogenides (TMDs) represent an exciting emergent class of long-lived
dipolar composite bosons in an atomically thin, near-ideal two-dimensional (2D)
system. The long-range interactions that arise from the spatial separation of
electrons and holes can give rise to novel quantum, as well as classical
multi-particle correlation effects. In order to acquire a detailed
understanding of the possible many-body effects, the fundamental interactions
between individual IXs have to be studied. Here, we trap a tunable number of
dipolar within a nanoscale confinement potential induced by placing a
MoSe-WSe hetero-bilayer (HBL) onto an array of SiO nanopillars. We
control the mean occupation of the IX trap via the optical excitation level and
observe discrete sharp-line emission from different configurations of
interacting IXs. We identify these features as different multiparticle states
with via their power dependencies and directly measure the
hierarchy of dipolar and exchange interactions as increases. The
interlayer biexciton () is found to be an emission doublet that is
blue-shifted from the single exciton by meV and split by
meV. The blueshift is even more pronounced for triexcitons
( meV), quadexcitons ( meV) and quintexcitons
( meV). These values are shown to be mutually consistent with
numerical modelling of dipolar excitons confined to a harmonic trapping
potential having a confinement lengthscale in the range nm. Our
results contribute to the understanding of interactions between IXs in TMD HBLs
at the discrete limit of only a few excitations and represent a key step
towards exploring quantum correlations between them.Comment: 15 pages, 3 figures plus Supplementary Information (19 pages, 11
pages
Large-scale quantum-emitter arrays in atomically thin semiconductors.
Quantum light emitters have been observed in atomically thin layers of transition metal dichalcogenides. However, they are found at random locations within the host material and usually in low densities, hindering experiments aiming to investigate this new class of emitters. Here, we create deterministic arrays of hundreds of quantum emitters in tungsten diselenide and tungsten disulphide monolayers, emitting across a range of wavelengths in the visible spectrum (610-680ânm and 740-820ânm), with a greater spectral stability than their randomly occurring counterparts. This is achieved by depositing monolayers onto silica substrates nanopatterned with arrays of 150-nm-diameter pillars ranging from 60 to 190ânm in height. The nanopillars create localized deformations in the material resulting in the quantum confinement of excitons. Our method may enable the placement of emitters in photonic structures such as optical waveguides in a scalable way, where precise and accurate positioning is paramount
Nonlinear Dispersion Relation and Out-of-Plane Second Harmonic Generation in MoSSe and WSSe Janus Monolayers
Janus transition metal dichalcogenides are an emerging class of atomically
thin materials with engineered broken mirror symmetry that gives rise to
long-lived dipolar excitons, Rashba splitting, and topologically protected
solitons. They hold great promise as a versatile nonlinear optical platform due
to their broadband harmonic generation tunability, ease of integration on
photonic structures, and nonlinearities beyond the basal crystal plane. Here,
we study second and third harmonic generation in MoSSe and WSSe Janus
monolayers. We use polarization-resolved spectroscopy to map the full
second-order susceptibility tensor of MoSSe, including its out-of-plane
components. In addition, we measure the effective third-order susceptibility,
and the second-order nonlinear dispersion close to exciton resonances for both
MoSSe and WSSe at room and cryogenic temperatures. Our work sets a bedrock for
understanding the nonlinear optical properties of Janus transition metal
dichalcogenides and probing their use in the next-generation on-chip
multifaceted photonic devices.Comment: 10 pages, 3 figures. SI: 8 pages, 5 figure
Charge carrier complexes in monolayer semiconductors
The photoluminescence (PL) spectra of monolayer (1L) semiconductors feature peaks ascribed to different charge-carrier complexes. We perform diffusion quantum Monte Carlo simulations of the binding energies of these complexes and examine their response to electric and magnetic fields. We focus on quintons (charged biexcitons), since they are the largest free charge-carrier complexes in undoped and low doping transition-metal dichalcogenides (TMDs). We examine the accuracy of the Rytova-Keldysh interaction potential between charges by comparing the binding energies (BEs) of charge-carrier complexes in 1L-TMDs with results obtained using ab initio interaction potentials. Magnetic fields 8 T change BEs by âź 0.2 meV T â 1 , in agreement with experiments, with BE variations of different complexes being very similar. Our results will help identify charge complexes in the PL spectra of 1L semiconductors
Measurements of branching fraction ratios and CP-asymmetries in suppressed B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^- decays
We report the first reconstruction in hadron collisions of the suppressed
decays B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^-, sensitive to the
CKM phase gamma, using data from 7 fb^-1 of integrated luminosity collected by
the CDF II detector at the Tevatron collider. We reconstruct a signal for the
B^- -> D(-> K^+ pi^-)K^- suppressed mode with a significance of 3.2 standard
deviations, and measure the ratios of the suppressed to favored branching
fractions R(K) = [22.0 \pm 8.6(stat)\pm 2.6(syst)]\times 10^-3, R^+(K) =
[42.6\pm 13.7(stat)\pm 2.8(syst)]\times 10^-3, R^-(K)= [3.8\pm 10.3(stat)\pm
2.7(syst]\times 10^-3, as well as the direct CP-violating asymmetry A(K) =
-0.82\pm 0.44(stat)\pm 0.09(syst) of this mode. Corresponding quantities for
B^- -> D(-> K^+ pi^-)pi^- decay are also reported.Comment: 8 pages, 1 figure, accepted by Phys.Rev.D Rapid Communications for
Publicatio
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems
We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.Peer ReviewedPostprint (published version
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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