680 research outputs found
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
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
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/
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
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
Single transit candidates from K2 : detection and period estimation
Photometric surveys such as Kepler have the precision to identify exoplanet and eclipsing binary candidates from only a single transit. K2, with its 75 d campaign duration, is ideally suited to detect significant numbers of single-eclipsing objects. Here we develop a Bayesian transit-fitting tool (‘Namaste: An Mcmc Analysis of Single Transit Exoplanets’) to extract orbital information from single transit events. We achieve favourable results testing this technique on known Kepler planets, and apply the technique to seven candidates identified from a targeted search of K2 campaigns 1, 2 and 3. We find EPIC203311200 to host an excellent exoplanet candidate with a period, assuming zero eccentricity, of 540+410 −230 d and a radius of 0.51 ± 0.05RJup. We also find six further transit candidates for which more follow-up is required to determine a planetary origin. Such a technique could be used in the future with TESS, PLATO and ground-based photometric surveys such as NGTS, potentially allowing the detection of planets in reach of confirmation by Gaia
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
Resource selection of deer hunters in Georgia\u27s Appalachian Mountains
White‐tailed deer (Odocoileus virginianus) and hunters on 2 Wildlife Management Areas (WMAs) within the Chattahoochee National Forest of northern Georgia, USA, significantly declined in number from the 1980s to 2018. Managers were interested in understanding how they could manipulate hunter distribution according to deer management goals. To understand the spatial distribution of hunting pressure and factors driving hunter resource selection, we analyzed GPS tracking data from 58 deer hunters over the 2018–2019 and 2019–2020 hunting seasons. We evaluated hunter selection on 3 spatial scales relative to elevation, slope, and distance from roads, trails, wildlife openings, deciduous forest, mixed forest, and evergreen forest. We incorporated covariates into 6 binary logistic regression models, plus a null model, within a used versus available framework. First, we compared hunter locations to available locations generated within the 2 WMAs. Elevation and distance to deciduous forest had the greatest effect on hunter selection, where hunters selected for lower elevations and closer proximity to deciduous forest. Second, we compared individual hunting bout locations to available locations generated within a buffer around the hunter\u27s starting location with a buffer radius equal to the maximum distance they travelled from their starting location. At the bout scale, distance to wildlife openings and elevation were the most important drivers of hunter selection; hunters selected areas closer to wildlife openings and higher elevations. Third, we compared individual hunter stand locations (used) to randomly selected locations along the hunter\u27s travel path (available). Only distance to roads and deciduous forest were significant in explaining hunter selection of stands. Hunters chose locations farther from roads and closer to deciduous forest relative to their travel paths. Mapping our WMA‐scale results revealed that only 5% of the total WMA area contained a greater relative probability of hunter selection compared to the probability of non‐selection. Our results suggest that vast refuge areas for deer likely existed on the WMAs during our study period. Manipulating hunter distribution is not necessary to aid in sustaining deer on either WMA at this time
Individual and combined associations between cardiorespiratory fitness and grip strength with common mental disorders: a prospective cohort study in the UK Biobank
Background:
Depression and anxiety are common mental disorders that increase physical health risks and are leading causes of global disability. Several forms of physical fitness could be modifiable risk factors for common mental disorders in the population. We examined associations between individual and combined markers of cardiorespiratory fitness and grip strength with the incidence of common mental disorders.
Methods:
A 7-year prospective cohort study in 152,978 UK Biobank participants. An exercise test and dynamometer were used to measure cardiorespiratory and grip strength, respectively. We used Patient Health Questionnaire-9 and Generalised Anxiety Disorder-7 scales to estimate the incidence of common mental disorders at follow-up.
Results:
Fully adjusted, longitudinal models indicated a dose-response relationship. Low and medium cardiorespiratory fitness was associated with 1.485 (95% CIs, 1.301 to 1.694, p < 0.001) and 1.141 (95% CIs, 1.005 to 1.297, p = 0.041) higher odds of depression or anxiety, compared to high cardiorespiratory fitness. Low and medium grip strength was associated with 1.381 (95% CIs, 1.315 to 1.452, p < 0.001) and 1.116 (95% CIs, 1.063 to 1.172, p < 0.001) higher odds of common mental disorder compared to high grip strength.
Individuals in the lowest group for both cardiorespiratory fitness and grip strength had 1.981 (95% CIs, 1.553 to 2.527, p < 0.001) higher odds of depression, 1.599 (95% CIs, 1.148 to 2.118, p = 0.004) higher odds of anxiety, and 1.814 (95% CIs, 1.461 to 2.252, p < 0.001) higher odds of either common mental disorder, compared to high for both types of fitness.
Conclusions:
Objective cardiorespiratory and muscular fitness markers represent modifiable risk factors for common mental disorders. Public health strategies to reduce common mental disorders could include combinations of aerobic and resistance activities
White-tailed deer (\u3ci\u3eOdocoileus virginianus\u3c/i\u3e) fawn survival and the influence of landscape characteristics on fawn predation risk in the Southern Appalachian Mountains, USA
In the Southern Appalachian region of the United States, harvest data has indicated the occurrence of low deer densities while exposing a trend of declining white-tailed deer (Odocoileus virginianus) populations over the past several decades in northern Georgia. A triumvirate of increasing fawn predator populations reside in the Southern Appalachian Mountains including coyotes (Canis latrans), black bears (Ursus americanus) and bobcats (Lynx rufus). This region is also characterized by a homogenous landscape composed of mature forests and sparse understory vegetation, likely lacking adequate cover to offer fawns refugia from predators. Our objectives were to estimate survival and cause-specific mortality rates of fawns while assessing a possible link between mortality risk, intrinsic fawn characteristics (i.e., birth mass, Julian birth date, sibling status), and landscape features within fawn usage areas. During 2018–2020, we radio-collared 71 fawns within the Chattahoochee National Forest of northern Georgia, USA and monitored survival to 12 weeks of age. We observed low fawn survival (cumulative = 0.157, 95% CI = 0.091–0.273; vaginal implant transmitter = 0.196, 95% CI = 0.096–0.403) with predation as the leading cause of all known mortalities (45 of 55 mortalities; 82%) due primarily to coyotes (n = 22), black bears (n = 12), and bobcats (n= 7). Relationships between landscape features and fawn predation risk were minimal with only one informative covariate. Increasing amounts of early successional land cover within fawn usage areas decreased fawn mortality risk within the first 20 days of life, but elevated mortality risk thereafter. All fawns with any amount of early successional land cover in their usage areas died of predation (n = 13) at various time intervals, suggesting limited areas of potential fawning cover may be targeted by predators. However, fawn predation risk seemed to be high regardless of landscape covariates due to the limited number of surviving fawns. Coyote-caused mortality occurred over a longer period at a consistently higher magnitude than all other forms of mortality, indicating possible delayed prey-switching behavior and coyote predation as an important factor of fawn survival. The low recruitment of fawns influenced by high predation rates and homogenous habitat conditions is likely the cause of deer population declines in the region
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