bluuebunny/crossref_metadata_2025_split huggingface dataset:
Persistent unexplained physical symptoms: a prospective longitudinal cohort study in UK primary care
Authors: Lamahewa Kethakie , Buszewicz Marta , Walters Kate , Marston Louise , Nazareth Irwin 
Published: January 2019

BackgroundUnexplained physical symptoms (UPS) are extremely common among primary care attenders, but little is known about their longer-term outcome.AimTo investigate the persistence of somatic symptoms at 6 months among a cohort with multiple UPS, and identify prognostic factors associated with worsening symptom scores.Design and settingProspective longitudinal cohort study involving adults attending UK general practice in North and Central London between January and December 2013.MethodConsecutive adults attending nine general practices were screened to identify those with at least three UPS. Eligible participants completed measures of symptom severity (measured using the Patient Health Questionnaire Somatic Symptom Module [PHQ-15]), physical and mental wellbeing, and past health and social history, and were followed up after 6 months. Multivariable linear regression analysis was conducted to identify prognostic factors associated with the primary outcome: somatic symptom severity.ResultsOverall, 245/294 (83%) provided 6-month outcome data. Of these, 135/245 (55%) reported still having UPS, 103/245 (42%) had symptoms still under investigation, and only 26/245 (11%) reported complete symptom resolution. Being female, higher baseline somatic symptom severity, poorer physical functioning, experience of childhood physical abuse, and perception of poor financial wellbeing were significantly associated with higher somatic symptom severity scores at 6 months.ConclusionThis study has shown that at 6 months few participants had complete resolution of unexplained somatic symptoms. GPs should be made aware of the likelihood of UPS persisting, and the factors that make this more likely, to inform decision making and care planning. There is a need to develop prognostic tools that can predict the risk of poor outcomes.
CBT to reduce healthcare use for medically unexplained symptoms: systematic review and meta-analysis
Authors: Jones Brittni , de C Williams Amanda C 
Published: January 2019

BackgroundStudies have reported that medically unexplained symptoms (MUS) tend to be associated with increased healthcare use, which is demanding of resources and potentially harmful to patients. This association is often used to justify the funding and study of psychological interventions for MUS, yet no systematic review has specifically examined the efficacy of psychological interventions in reducing healthcare use.AimTo conduct a systematic review and meta-analysis to evaluate the effectiveness of cognitive behavioural therapies (CBT) for MUS in reducing healthcare use.Design and settingSystematic review and meta-analysis.MethodThe search from a previous systematic review was updated and expanded. Twenty-two randomised controlled trials reported healthcare use, of which 18 provided data for meta-analysis. Outcomes were healthcare contacts, healthcare costs, medication, and medical investigations.ResultsSmall reductions in healthcare contacts and medication use were found for CBT compared with active controls, treatment as usual, and waiting list controls, but not for medical investigations or healthcare costs.ConclusionCognitive behavioural interventions show weak benefits in reducing healthcare use in people with MUS. The imprecise use of MUS as a diagnostic label may impact on the effectiveness of interventions, and it is likely that the diversity and complexity of these difficulties may necessitate a more targeted approach.
The Near-ultraviolet Continuum Radiation in the Impulsive Phase of HF/GF-type dMe Flares. I. Data
Authors: Kowalski Adam F. , Wisniewski John P. , Hawley Suzanne L. , Osten Rachel A. , Brown Alexander , Fariña Cecilia , Valenti Jeff A. , Brown Stephen , Xilouris Manolis , Schmidt Sarah J. , Johns-Krull Christopher 
Published: January 2019

Abstract
We present near-UV (NUV) flare spectra from the Hubble Space Telescope (HST)/Cosmic Origins Spectrograph during two moderate-amplitude U-band flares on the dM4e star GJ 1243. These spectra are some of the first accurately flux-calibrated, NUV flare spectra obtained over the impulsive phase in M dwarf flares. We observed these flares with a fleet of nine ground-based telescopes simultaneously, which provided broadband photometry and low-resolution spectra at the Balmer jump. An increase in the broadband continuum occurred with a signal-to-noise ratio >20 in the HST spectra, while numerous Fe ii lines and the Mg ii lines also increased but with smaller flux enhancements than the continuum radiation. These two events produced the most prominent Balmer line radiation and the largest Balmer jumps that have been observed to date in dMe flare spectra. A T = 9000 K blackbody underestimates the NUV continuum flare flux by a factor of two and is a poor approximation to the white light in these types of flare events. Instead, our data suggest that the peak of the specific continuum flux density is constrained to U-band wavelengths near the Balmer series limit. A radiative-hydrodynamic simulation of a very high energy deposition rate averaged over times of impulsive heating and cooling better explains the properties of the λ > 2500 Å flare continuum. These two events sample only one end of the empirical color–color distribution for dMe flares, and more time-resolved flare spectra in the NUV, U band, and optical from 2000 to 4200 Å are needed during more impulsive and/or more energetic flares.
Keck OSIRIS AO LIRG Analysis (KOALA): Feedback in the Nuclei of Luminous Infrared Galaxies
Authors: U Vivian , Medling Anne M. , Inami Hanae , Armus Lee , Díaz-Santos Tanio , Charmandaris Vassilis , Howell Justin , Stierwalt Sabrina , Privon George C. , Linden Sean T. , Sanders David B. , Max Claire E. , Evans Aaron S. , Barcos-Muñoz Loreto , Chiang Charleston W. K. , Appleton Phil , Canalizo Gabriela , Fazio Giovanni , Iwasawa Kazushi , Larson Kirsten , Mazzarella Joseph , Murphy Eric , Rich Jeffrey , Surace Jason 
Published: January 2019

Abstract
The role of feedback in triggering or quenching star formation and hence driving galaxy evolution can be directly studied with high-resolution integral field observations. The manifestation of feedback in shocks is particularly important to examine in galaxy mergers, where violent interactions of gas take place in the interstellar medium during the course of the galactic collision. As part of our effort to systematically study the local population of luminous infrared galaxies within the Great Observatories All-Sky LIRG Survey, we undertook the Keck OSIRIS AO LIRG Analysis observing campaign to study the gas dynamics in the inner kiloparsec regions of these systems at spatial scales of a few tens of pc. With high-resolution near-infrared adaptive optics–assisted integral field observations taken with OSIRIS on the Keck Telescopes, we employ near-infrared diagnostics such as Brγ and the rovibrationally excited H2 lines to quantify the nuclear star formation rate and identify feedback associated with shocked molecular gas seen in 21 nearby luminous infrared galaxies. Shocked molecular gas is preferentially found in the ultraluminous infrared systems but may also be triggered at a lower-luminosity, earlier merging stage. On circumnuclear scales, AGNs have a strong effect on heating the surrounding molecular gas, though their coupling is not simply driven by AGN strength but rather is complicated by orientation, dust shielding, density, and other factors. We find that nuclear star formation correlates with merger class and diminishing projected nuclear separations. These trends are largely consistent with the picture of merger-induced starbursts in the center of galaxy mergers.
Generalization of the Magnetic Field Configuration of Typical and Atypical Confined Flares
Authors: Joshi Navin Chandra , Zhu Xiaoshuai , Schmieder Brigitte , Aulanier Guillaume , Janvier Miho , Joshi Bhuwan , Magara Tetsuya , Chandra Ramesh , Inoue Satoshi 
Published: January 2019

Abstract
Atypical flares cannot be naturally explained with standard models. To predict such flares, we need to define their physical characteristics, in particular, their magnetic environment, and identify pairs of reconnected loops. Here, we present in detail a case study of a confined flare preceded by flux cancellation that leads to the formation of a filament. The slow rise of the noneruptive filament favors the growth and reconnection of overlying loops. The flare is only of C5.0 class but it is a long duration event. The reason is that it is comprised of three successive stages of reconnection. A nonlinear force-free field extrapolation and a magnetic topology analysis allow us to identify the loops involved in the reconnection process and build a reliable scenario for this atypical confined flare. The main result is that a curved magnetic polarity inversion line in active regions is a key ingredient for producing such atypical flares. A comparison with previous extrapolations for typical and atypical confined flares leads us to propose a cartoon for generalizing the concept.
Morphologies of ∼190,000 Galaxies at z = 0–10 Revealed with HST Legacy Data. III. Continuum Profile and Size Evolution of Lyα Emitters
Authors: Shibuya Takatoshi , Ouchi Masami , Harikane Yuichi , Nakajima Kimihiko 
Published: January 2019

Abstract
We present the redshift evolution of the radial surface brightness profile of the rest-frame UV and optical stellar continua for 9119 Lyα emitters (LAEs) at z ≃ 0–8 and 0–2, respectively. Using Hubble Space Telescope data and the LAE catalogs taken from the literature, we derive the structural quantities of the 9119 LAEs, and of ≃180,000 of photo-z star-forming galaxies (SFGs) and Lyman break galaxies (LBGs) for comparison, by the well-tested profile fitting. From 936 well-fitted LAEs, we carefully define a homogeneous sample of LAEs falling in the same ranges of UV-continuum luminosity and Lyα equivalent width over z ≃ 0–8, and evaluate the redshift evolution. We find that the distribution of effective radius r
e is represented by a log-normal function, and that the median Sérsic index is almost constant at n ≃ 1–1.5 for the LAEs over z ≃ 0–7, suggesting that typical LAEs have a stellar-disk morphology. The size–luminosity relation of the LAEs decreases monotonically toward high z, following size–luminosity relations of SFGs and LBGs. The median r
e values of the LAEs evolve significantly as r
e ∝ (1 + z)−1.37, similar to those of the SFGs and LBGs in the same luminosity range, in contrast with the claims of no evolution made by previous studies, whose LAE samples are probably biased to faint sources at low z. The r
e distribution, star formation rate surface densities, and stellar-to-halo size ratios of the LAEs are comparable with those of the SFGs and LBGs, indicating that LAEs have stellar components similar to SFGs and LBGs with a Lyα emissivity controlled by non-stellar physics such as the geometry, kinematics, and ionization states of the interstellar/circumgalactic medium.
Simultaneous X-Ray and Infrared Observations of Sagittarius A*'s Variability
Authors: Boyce H. , Haggard D. , Witzel G. , Willner S. P. , Neilsen J. , Hora J. L. , Markoff S. , Ponti G. , Baganoff F. , Becklin E. E. , Fazio G. G. , Lowrance P. , Morris M. R. , Smith H. A. 
Published: January 2019

Abstract
Emission from Sagittarius A* is highly variable at both X-ray and infrared (IR) wavelengths. Observations over the last ∼20 yr have revealed X-ray flares that rise above a quiescent thermal background about once per day, while faint X-ray flares from Sgr A* are undetectable below the constant thermal emission. In contrast, the IR emission of Sgr A* is observed to be continuously variable. Recently, simultaneous observations have indicated a rise in IR flux density around the same time as every distinct X-ray flare, while the opposite is not always true (peaks in the IR emission may not be coincident with an X-ray flare). Characterizing the behavior of these simultaneous X-ray/IR events and measuring any time lag between them can constrain models of Sgr A*'s accretion flow and the flare emission mechanism. Using 100+ hours of data from a coordinated campaign between the Spitzer Space Telescope and the Chandra X-ray Observatory, we present results of the longest simultaneous IR and X-ray observations of Sgr A* taken to date. The cross-correlation between the IR and X-ray light curves in this unprecedented data set, which includes four modest X-ray/IR flares, indicates that flaring in the X-ray may lead the IR by approximately 10–20 min with 68% confidence. However, the 99.7% confidence interval on the time-lag also includes zero, i.e., the flaring remains statistically consistent with simultaneity. Long-duration and simultaneous multi-wavelength observations of additional bright flares will improve our ability to constrain the flare timing characteristics and emission mechanisms, and must be a priority for Galactic Center observing campaigns.
Photochemistry in Hot H2-dominated Exoplanet Atmospheres
Authors: Fleury Benjamin , Gudipati Murthy S. , Henderson Bryana L. , Swain Mark 
Published: January 2019

Abstract
Photochemistry has the potential to substantially impact the atmospheric composition of exoplanets with consequences on the radiative transfer, thermal structure, and dynamics of the atmospheres, particularly in UV-rich stellar environments. Here, we present the results of a first laboratory experimental simulation of photochemistry in carbon-rich exoplanet atmospheres at elevated temperatures. The evolution of gas-phase molecular composition was quantitatively monitored with infrared spectroscopy and mass spectrometry. We found that H2/CO gas compositions can change significantly from thermal equilibria compositions when irradiated with Lyα photons at temperatures ranging from 600 to 1500 K. Carbon dioxide and water were found to be the main products caused by photolysis, while the formation of methane was also observed to a lesser extent. We find that photochemistry efficiency is strongly correlated with increasing temperature. Our finding that water is efficiently produced by photochemistry in a supersolar C/O = 1 environment, representing C enhancement relative to solar values C/O ratio = 0.54, has significant implications for the interpretation of many exoplanet transmission spectra. We also find the formation of an organic solid condensate at 1500 K and under Lyα UV radiation, confirming the possibility of forming photochemical hazes in hot-Jupiter exoplanet atmospheres with an enhanced C/O ratio compared to solar.
Kinetic Energy Transfer from X-Ray Ultrafast Outflows to Millimeter/Submillimeter Cold Molecular Outflows in Seyfert Galaxies
Authors: Mizumoto Misaki , Izumi Takuma , Kohno Kotaro 
Published: January 2019

Abstract
UltraFast Outflows (UFOs), seen as X-ray blueshifted absorption lines in active galactic nuclei (AGNs), are considered to be a key mechanism for AGN feedback. In this scenario, UFO kinetic energy is transferred into the cold and extended molecular outflow observed at the millimeter/submillimeter wavelength, which blows away the gas and suppresses star formation and accretion onto the central black hole (BH). However, the energy transfer between the inner UFO and the outer molecular outflow has not yet been fully studied mainly due to the limited sample. In this paper, we perform a comparison of their kinetic energy using the millimeter/submillimeter published data and the X-ray archival data. Among 14 Seyfert galaxies whose molecular outflows are detected in the Institut de RAdioastronomie Millimétrique/Plateau de Bure Interferometer data, 8 targets are bright enough to perform spectral fitting in X-ray, and we have detected UFO absorption lines in 6 targets with a 90% significance level, using XMM-Newton and Suzaku satellites. The time-averaged UFO kinetic energy was derived from the spectral fitting. As a result, we have found that the energy-transfer rate (kinetic energy ratio of the molecular outflow to the UFO) ranges from ∼7 × 10−3 to ∼1, and has a negative correlation with the BH mass, which shows that the AGN feedback is more efficient in the lower mass BHs. This tendency is consistent with the theoretical prediction that the cooling timescale of the outflowing gas becomes longer than the flow timescale when the BH mass is smaller.
Quantifying How Density Gradients and Front Curvature Affect Carbon Detonation Strength during SNe Ia
Authors: Miles Broxton J. , Townsley Dean M. , Shen Ken J. , Timmes F. X. , Moore Kevin 
Published: January 2019

Abstract
Accurately reproducing the physics behind the detonations of SNe Ia and the resultant nucleosynthetic yields is important for interpreting observations of spectra and remnants. The scales of the processes involved span orders of magnitudes, making the problem computationally impossible to ever fully resolve in full-star simulations in the present and near future. In the lower density regions of the star, the curvature of the detonation front will slow the detonation, affecting the production of intermediate mass elements. We find that shock strengthening due to the density gradient present in the outer layers of the progenitor is essential for understanding the nucleosynthesis there, with burning extending well below the density at which a steady-state detonation is extinct. We show that a complete reaction network is not sufficient to obtain physical detonations at high densities and modest resolution due to numerical mixing at the unresolved reaction front. At low densities, below 6 × 105 g cm−3, it is possible to achieve high enough resolution to separate the shock and the reaction region, and the abundance structure predicted by fully resolved quasi-steady-state calculations is obtained. For our best current benchmark yields, we utilize a method in which the unresolved portion of Lagrangian histories are reconstructed based on fully resolved quasi-steady-state detonation calculations. These computations demonstrate that under-resolved simulations agree approximately, ∼10% in post-shock values of temperature, pressure, density, and abundances, with expected detonation structures sufficiently far from the under-resolved region, but that there is still room for some improvement in the treatment of subgrid reactions in the hydrodynamics to before better than 1% can be achieved at all densities.
AstroSat SXT Observations of Her X-1
Authors: Leahy D. A. , Chen Y. 
Published: January 2019

Abstract
Two observations of the X-ray binary system Her X-1 by the AstroSat Soft X-ray Telescope were carried out in 2017. The first was during Low State and Turn-On, the second was during Main High State without and with dips. During Main High without dips, the power-law continuum, 1 keV emission line complex, and soft blackbody-like emission from Her X-1 are detected. Evidence is found in the spectrum for a highly ionized absorber, consistent with the recently detected corona in Her X-1. The X-ray spectra from different states are compared. The 6.4 keV fluorescent iron line is clearly detected in Low State. The different spectrum components are highly variable between states.
Mapping the Conditions for Hydrodynamic Instability on Steady-State Accretion Models of Protoplanetary Disks
Authors: Pfeil Thomas , Klahr Hubert 
Published: January 2019

Abstract
Hydrodynamic instabilities in disks around young stars depend on the thermodynamic stratification of the disk and on the local rate of thermal relaxation. Here, we map the spatial extent of unstable regions for the Vertical Shear Instability (VSI), the Convective Overstability (COS), and the amplification of vortices via the Subcritical Baroclinic Instability (SBI). We use steady-state accretion disk models, including stellar irradiation, accretion heating, and radiative transfer. We determine the local radial and vertical stratification and thermal relaxation rate in the disk, which depends on the stellar mass, disk mass, and mass accretion rate. We find that passive regions of disks—that is, the midplane temperature dominated by irradiation—are COS unstable about one pressure scale height above the midplane and VSI unstable at radii >10 au. Vortex amplification via SBI should operate in most parts of active and passive disks. For active parts of disks (midplane temperature determined by accretion power), COS can become active down to the midplane. The same is true for the VSI because of the vertically adiabatic stratification of an internally heated disk. If hydrodynamic instabilities or other nonideal MHD processes are able to create α-stresses (>10−5) and released accretion energy leads to internal heating of the disk, hydrodynamic instabilities are likely to operate in significant parts of the planet-forming zones in disks around young stars, driving gas accretion and flow structure formation. Thus, hydrodynamic instabilities are viable candidates to explain the rings and vortices observed with the Atacama Large Millimeter/submillimeter Array and Very Large Telescope.
Identifying Variability in Deeply Embedded Protostars with ALMA and CARMA
Authors: Francis Logan , Johnstone Doug , Dunham Michael M. , Hunter Todd R. , Mairs Steve 
Published: January 2019

Abstract
Variability of pre-main-sequence stars observed at optical wavelengths has been attributed to fluctuations in the mass accretion rate from the circumstellar disk onto the forming star. Detailed models of accretion disks suggest that young deeply embedded protostars should also exhibit variations in their accretion rates, and that these changes can be tracked indirectly by monitoring the response of the dust envelope at mid-IR to millimeter wavelengths. Interferometers such as the Atacama Large Millimeter/submillimeter Array (ALMA) offer the resolution and sensitivity to observe small fluctuations in brightness at the scale of the disk where episodic accretion may be driven. In this work, we present novel methods for comparing interferometric observations and apply them to Combined Array for Research in Millimeter-wave Astronomy (CARMA) and ALMA 1.3 mm observations of deeply embedded protostars in Serpens taken 9 yr apart. We find no brightness variation above the limits of our analysis of a factor of ≳50%, due to the limited sensitivity of the CARMA observations and small number of sources common to both epochs. We further show that follow-up ALMA observations with a similar sample size and sensitivity may be able to uncover variability at the level of a few percent, and discuss implications for future work.
Octahedron-based Projections as Intermediate Representations for Computer Imaging: TOAST, TEA, and More
Authors: McGlynn Thomas , Fay Jonathan , Wong Curtis , Rosenfield Philip 
Published: January 2019

Abstract
This paper defines and discusses a set of rectangular all-sky projections that have no singular points, notably the Tesselated Octahedral Adaptive Spherical Transformation (or TOAST) developed initially for the WorldWide Telescope. These have proven to be useful as intermediate representations for imaging data where the application transforms dynamically from a standardized internal format to a specific format (projection, scaling, orientation, etc.) requested by the user. TOAST is strongly related to the Hierarchical Triangular Mesh pixelization and is particularly well adapted to situations where one wishes to traverse a hierarchy of images increasing in resolution. Because it can be recursively computed using a very simple algorithm it is particularly adaptable to use with graphical processing units.