769 research outputs found
Electric Dipole Moment of a BPS Monopole
Monopole ``superpartner'' solutions are constructed by acting with finite,
broken supersymmetry transformations on a bosonic N=2 BPS monopole. The terms
beyond first order in this construction represent the backreaction of the the
fermionic zero-mode state on the other fields. Because of the quantum nature of
the fermionic zero-modes, the superpartner solution is necessarily operator
valued. We extract the electric dipole moment operator and show that it is
proportional to the fermion zero-mode angular momentum operator with a
gyroelectric ratio g=2. The magnetic quadrupole operator is shown to vanish
identically on all states. We comment on the usefulness of the monopole
superpartner solution for a study of the long-range spin dependent dynamics of
BPS monopoles.Comment: 8 pages, references and note adde
Scintillation noise in exoplanet transit photometry.
Transit photometry is a powerful technique for studying exoplanets. Transit observations from the ground of targets of magnitude V= 10 or brighter, however, are limited by scintillation noise due to Earth's atmosphere. Through turbulence profiling using instruments such as the stereo-SCIDAR, we have shown to able to accurately model scintillation noise, which is essential in order to fully account for the error budget of the observation. Through numerical modelling we find that employing scintillation reducing techniques enables an improvement of a factor between 1.36 — 1.6 on the astrophysical parameters
Support received after bereavement by suicide and other sudden deaths:a cross-sectional UK study of 3,432 young bereaved adults
OBJECTIVE: To test the hypothesis that people bereaved by suicide are less likely to receive formal or informal support than people bereaved by other causes of sudden death. DESIGN: National cross-sectional study. SETTING: Adults working or studying at any UK higher education institution (HEI) in 2010. PARTICIPANTS: A total of 3432 eligible respondents aged 18-40 years bereaved by the sudden death of a close friend or relative, sampled from approximately 659 572 bereaved and non-bereaved staff and students at 37 of 164 UK HEIs invited to participate. EXPOSURES: Bereavement by suicide (n=614; 18%), by sudden unnatural causes (n=712; 21%) and by sudden natural causes (n=2106; 61%). MAIN OUTCOME MEASURES: Receipt of formal and informal support postbereavement; timing of valued support. RESULTS: 21% (725/3432) of our sample of bereaved adults reported receiving no formal or informal bereavement support, with no evidence for group differences. People bereaved by suicide were less likely to have received informal support than those bereaved by sudden natural causes (adjusted OR (AOR)=0.79; 95% CI 0.64 to 0.98) or unnatural causes (AOR=0.74; 95% CI 0.58 to 0.96) but did not differ from either comparison group on receipt of formal support. People bereaved by suicide were less likely to have received immediate support (AOR=0.73; 95% CI 0.59 to 0.90) and more likely to report delayed receipt of support (AOR=1.33; 95% CI 1.08 to 1.64) than people bereaved by sudden natural causes. Associations were not modified by gender, or age bereaved, but became non-significant when adjusting for stigma. CONCLUSIONS: People bereaved by suicide are less likely to receive informal support than people bereaved by other causes of sudden death and are more likely to perceive delays in accessing any support. This is concerning given their higher risk of suicide attempt and the recommendations within suicide prevention strategies regarding their need for support. STUDY REGISTRATION: http://www.ucl.ac.uk/psychiatry/bereavementstudy/
Dyons and S-Duality in N=4 Supersymmetric Gauge Theory
We analyze the spectrum of dyons in N=4 supersymmetric Yang-Mills theory with
gauge group SU(3) spontaneously broken down to U(1)xU(1). The Higgs fields
select a natural basis of simple roots. Acting with S-duality on the W-boson
states corresponding to simple roots leads to an orbit of BPS dyon states that
are magnetically charged with respect to one of the U(1)'s. The corresponding
monopole solutions can be obtained by embedding SU(2) monopoles into SU(3) and
the S-duality predictions reduce to the SU(2) case. Acting with S-duality on
the W-boson corresponding to a non-simple root leads to an infinite set of new
S-duality predictions. The simplest of these corresponds to the existence of a
harmonic form on the moduli space of SU(3) monopoles that have magnetic charge
(1,1) with respect to the two U(1)'s. We argue that the moduli space is given
by R^3x(R^1xM)/Z_2, where M is Euclidean Taub-NUT space, and that the latter
admits the appropriate normalizable harmonic two form. We briefly discuss the
generalizations to other gauge groups.Comment: 13 pages (Harvmac b), discrete identification corrected, reference
adde
One of the closest exoplanet pairs to the 3:2 Mean Motion Resonance: K2-19b \& c
The K2 mission has recently begun to discover new and diverse planetary
systems. In December 2014 Campaign 1 data from the mission was released,
providing high-precision photometry for ~22000 objects over an 80 day timespan.
We searched these data with the aim of detecting further important new objects.
Our search through two separate pipelines led to the independent discovery of
K2-19b \& c, a two-planet system of Neptune sized objects (4.2 and 7.2
), orbiting a K dwarf extremely close to the 3:2 mean motion
resonance. The two planets each show transits, sometimes simultaneously due to
their proximity to resonance and alignment of conjunctions. We obtain further
ground based photometry of the larger planet with the NITES telescope,
demonstrating the presence of large transit timing variations (TTVs), and use
the observed TTVs to place mass constraints on the transiting objects under the
hypothesis that the objects are near but not in resonance. We then
statistically validate the planets through the \texttt{PASTIS} tool,
independently of the TTV analysis.Comment: 18 pages, 10 figures, accepted to A&A, updated to match published
versio
Mental disorders across the adult life course and future coronary heart disease: evidence for general susceptibility
BACKGROUND: Depression, anxiety, and psychotic disorders have been associated with an increased risk of coronary heart disease (CHD). It is unclear whether this association between mental health and CHD is present across a wider range of mental disorders.METHODS AND RESULTS: Participants were 1 107 524 Swedish men conscripted at a mean age of 18.3 years. Mental disorders were assessed by psychiatric interview on conscription, and data on hospital admissions for mental disorder and CHD were obtained from national registers during 22.6 years of follow-up. An increased risk of incident CHD was evident across a range of mental disorders whether diagnosed at conscription or on later hospital admission. Age-adjusted hazard ratios (95% confidence intervals) according to diagnoses at conscription ranged from 1.30 (1.05-1.60) (depressive disorders) to 1.92 (1.60-2.31) (alcohol-related disorders). The equivalent figures according to diagnoses during hospital admission ranged from 1.49 (1.24-1.80) (schizophrenia) to 2.82 (2.53-3.13) (other substance use disorders). Associations were little changed by adjustment for parental socioeconomic status, or body mass index, diabetes mellitus, and blood pressure measured at conscription, but they were partially attenuated by the adjustment for smoking, alcohol intake, and intelligence measured at conscription, and for education and own socioeconomic position.CONCLUSIONS: Increased risk of incident CHD is present across a range of mental disorders and is observable when the disorders are diagnosed at a young age
The host stars of Kepler's habitable exoplanets : superflares, rotation and activity
We embark on a detailed study of the light curves of Kepler's most Earth-like exoplanet host stars using the full length of Kepler data. We derive rotation periods, photometric activity indices, flaring energies, mass-loss rates, gyrochronological ages, X-ray luminosities and consider implications for the planetary magnetospheres and habitability. Furthermore, we present the detection of superflares in the light curve of Kepler-438, the exoplanet with the highest Earth Similarity Index to date. Kepler-438b orbits at a distance of 0.166 au to its host star, and hence may be susceptible to atmospheric stripping. Our sample is taken from the Habitable Exoplanet Catalogue, and consists of the stars Kepler-22, Kepler-61, Kepler-62, Kepler-174, Kepler-186, Kepler-283, Kepler-296, Kepler-298, Kepler-438, Kepler-440, Kepler-442, Kepler-443 and KOI-4427, between them hosting 15 of the most habitable transiting planets known to date from Kepler
Sum rules and three point functions
Sum rules constraining the R-current spectral densities are derived
holographically for the case of D3-branes, M2-branes and M5-branes all at
finite chemical potentials. In each of the cases the sum rule relates a certain
integral of the spectral density over the frequency to terms which depend both
on long distance physics, hydrodynamics and short distance physics of the
theory. The terms which which depend on the short distance physics result from
the presence of certain chiral primaries in the OPE of two R-currents which are
turned on at finite chemical potential. Since these sum rules contain
information of the OPE they provide an alternate method to obtain the structure
constants of the two R-currents and the chiral primary. As a consistency check
we show that the 3 point function derived from the sum rule precisely matches
with that obtained using Witten diagrams.Comment: 41 page
Impact of a nurse-led intervention to improve screening for cardiovascular risk factors in people with severe mental illnesses. Phase-two cluster randomised feasibility trial of community mental health teams
Background: People with severe mental illnesses (SMI) are at increased risk of cardiovascular disease (CVD). Clinical guidelines recommend regular screening for CVD risk factors. We evaluated a nurse led intervention to improve screening rates across the primary-secondary care interface.Methods: Six community mental health teams (CMHTs) were randomised to receive either the nurse led intervention plus education pack (n = 3) or education pack only (n = 3). Intervention (6 months): The nurse promoted CVD screening in primary care and then in CMHTs. Patients who remained unscreened were offered screening by the nurse. After the intervention participants with SMI were recruited from each CMHT to collect outcome data. Main outcome: Numbers screened during the six months, confirmed in General Practice notes.Results: All six CMHTs approached agreed to randomisation. 121 people with SMI participated in outcome interviews during two waves of recruitment (intervention arm n = 59, control arm n = 62). Participants from both arms of the trial had similar demographic profiles and rates of previous CVD screening in the previous year, with less than 20% having been screened for each risk factor. After the trial, CVD screening had increased in both arms but participants from the intervention arm were significantly more likely to have received screening for blood pressure (96% vs 68%; adjusted Odds Ratio (OR) 13.6; 95% CI: 3.5-38.4), cholesterol (66.7% vs 26.9%, OR 6.1; 3.2-11.5), glucose (66.7% vs 36.5% OR 4.4; 2.7-7.1), BMI (92.5% vs 65.2% OR 6.5; 2.1-19.6), and smoking status (88.2% vs 57.8% OR 5.5; 3.2-9.5) and have a 10 year CVD risk score calculated (38.2% vs 10.9%) OR 5.2 1.8-15.3). Within the intervention arm approximately half the screening was performed in general practice and half by the trial nurse.Conclusions: The nurse-led intervention was superior, resulting in an absolute increase of approximately 30% more people with SMI receiving screening for each CVD risk factor. The feasibility of the trial was confirmed in terms of CMHT recruitment and the intervention, but the response rate for outcome collection was disappointing; possibly a result of the cluster design. The trial was not large or long enough to detect changes in risk factors.Trial Registration: International Standard Randomised Controlled Trial Registration Number (ISRCTRN) 58625025
VUV Photoionization Cross Sections of HO_2, H_2O_2, and H_2CO
The absolute vacuum ultraviolet (VUV) photoionization spectra of the hydroperoxyl radical (HO_2), hydrogen peroxide (H_2O_2), and formaldehyde (H_2CO) have been measured from their first ionization thresholds to 12.008 eV. HO_2, H_2O_2, and H_2CO were generated from the oxidation of methanol initiated by pulsed-laser-photolysis of Cl_2 in a low-pressure slow flow reactor. Reactants, intermediates, and products were detected by time-resolved multiplexed synchrotron photoionization mass spectrometry. Absolute concentrations were obtained from the time-dependent photoion signals by modeling the kinetics of the methanol oxidation chemistry. Photoionization cross sections were determined at several photon energies relative to the cross section of methanol, which was in turn determined relative to that of propene. These measurements were used to place relative photoionization spectra of HO_2, H_2O_2, and H_2CO on an absolute scale, resulting in absolute photoionization spectra
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