bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constraining mixing in massive stars in the Small Magellanic Cloud
Authors: Schootemeijer A. , Langer N. , Grin N. J. , Wang C. 
Published: April 2019

Context. The evolution of massive stars is strongly influenced by internal mixing processes such as semiconvection, convective core overshooting, and rotationally induced mixing. None of these processes are currently well constrained.
Aims. We investigate models for massive stars in the Small Magellanic Cloud (SMC), for which stellar-wind mass loss is less important than for their metal-rich counterparts. We aim to constrain the various mixing efficiencies by comparing model results to observations.
Methods. For this purpose, we use the stellar-evolution code MESA to compute more than 60 grids of detailed evolutionary models for stars with initial masses of 9…100 M⊙, assuming different combinations of mixing efficiencies of the various processes in each grid. Our models evolve through core hydrogen and helium burning, such that they can be compared with the massive main sequence and supergiant population of the SMC.
Results. We find that for most of the combinations of the mixing efficiencies, models in a wide mass range spend core-helium burning either only as blue supergiants, or only as red supergiants. The latter case corresponds to models that maintain a shallow slope of the hydrogen/helium (H/He) gradient separating the core and the envelope of the models. Only a small part of the mixing parameter space leads to models that produce a significant number of blue and red supergiants, which are both in abundance in the SMC. Some of our grids also predict a cut-off in the number of red supergiants above log L/L⊙ = 5…5.5. Interestingly, these models contain steep H/He gradients, as is required to understand the hot, hydrogen-rich Wolf-Rayet stars in the SMC. We find that unless it is very fast, rotation has a limited effect on the H/He profiles in our models.
Conclusions. While we use specific implementations of the considered mixing processes, they comprehensively probe the two first-order structural parameters, the core mass and the H/He gradient in the core-envelope interface. Our results imply that in massive stars, mixing during the main-sequence evolution leads to a moderate increase in the helium core masses, and also that the H/He gradients above the helium cores become very steep. Our model grids can be used to further refine the various mixing efficiencies with the help of future observational surveys of the massive stars in the SMC, and thereby help to considerably reduce the uncertainties in models of massive star evolution.
Young stellar populations in early-type dwarf galaxies
Authors: Hamraz E. , Peletier R. F. , Khosroshahi H. G. , Valentijn E. A. , den Brok M. , Venhola A. 
Published: April 2019

Aims. To understand the stellar population content of early-type dwarf galaxies (dEs) and their environmental dependence, we compare the slopes and intrinsic scatter of color–magnitude relations (CMRs) for three nearby clusters, Fornax, Virgo, and Coma. Additionally, we present and compare internal color profiles of these galaxies to identify central blue regions with younger stars.
Methods. We use the imaging of the HST/ACS Fornax cluster in the magnitude range of −18.7 ≤ Mg′ ≤ −16.0 to derive magnitudes, colors, and color profiles, which we compare with literature measurements from the HST/ACS Virgo and Coma Cluster Survey. We take advantage of HST accuracy to investigate and parameterize the (g′−z′) color profiles of these dEs.
Results. Based on analysis of the color profiles, we report on a large number of dEs with young stellar populations at their center in all three clusters. While for Virgo and Coma the number of blue-cored dEs is found to be 85%±2% and 53%±3%, respectively, for Fornax, we find that all galaxies have a blue core. We show that bluer cores reside in fainter dEs, similar to the trend seen in nucleated dEs. We find no correlation between the luminosity of the galaxy and the size of its blue core. Moreover, a comparison of the CMRs of the three clusters shows that the scatter in the CMR of Virgo is considerably larger than in the Fornax and Coma clusters. Presenting adaptive smoothing we show that the galaxies on the blue side of the CMR often show evidence for dust extinction, which strengthens the interpretation that the bluer colors are due to young stellar populations. We also find that outliers on the red side of the CMR are more compact than what is expected for their luminosity. We find several of these red outliers in Virgo, often close to more massive galaxies. No red outlying compact early-types are found in Fornax and Coma in this magnitude range while we find three in the Virgo cluster. We show that the CMR of the Fornax and Virgo clusters are slightly bluer than that of Coma. We suggest that the large number of outliers and larger scatter found for Virgo CMR are a result of the alternative assembly history of this cluster.
Thermal properties of slowly rotating asteroids: results from a targeted survey
Authors: Marciniak A. , Alí-Lagoa V. , Müller T. G. , Szakáts R. , Molnár L. , Pál A. , Podlewska-Gaca E. , Parley N. , Antonini P. , Barbotin E. , Behrend R. , Bernasconi L. , Butkiewicz-Bąk M. , Crippa R. , Duffard R. , Ditteon R. , Feuerbach M. , Fauvaud S. , Garlitz J. , Geier S. , Goncalves R. , Grice J. , Grześkowiak I. , Hirsch R. , Horbowicz J. , Kamiński K. , Kamińska M. K. , Kim D.-H. , Kim M.-J. , Konstanciak I. , Kudak V. , Kulczak P. , Maestre J. L. , Manzini F. , Marks S. , Monteiro F. , Ogłoza W. , Oszkiewicz D. , Pilcher F. , Perig V. , Polakis T. , Polińska M. , Roy R. , Sanabria J. J. , Santana-Ros T. , Skiff B. , Skrzypek J. , Sobkowiak K. , Sonbas E. , Thizy O. , Trela P. , Urakawa S. , Żejmo M. , Żukowski K. 
Published: April 2019

Context.Earlier work suggests that slowly rotating asteroids should have higher thermal inertias than faster rotators because the heat wave penetrates deeper into the subsurface. However, thermal inertias have been determined mainly for fast rotators due to selection effects in the available photometry used to obtain shape models required for thermophysical modelling (TPM).Aims.Our aims are to mitigate these selection effects by producing shape models of slow rotators, to scale them and compute their thermal inertia with TPM, and to verify whether thermal inertia increases with the rotation period.Methods.To decrease the bias against slow rotators, we conducted a photometric observing campaign of main-belt asteroids with periods longer than 12 h, from multiple stations worldwide, adding in some cases data from WISE andKeplerspace telescopes. For spin and shape reconstruction we used the lightcurve inversion method, and to derive thermal inertias we applied a thermophysical model to fit available infrared data from IRAS, AKARI, and WISE.Results.We present new models of 11 slow rotators that provide a good fit to the thermal data. In two cases, the TPM analysis showed a clear preference for one of the two possible mirror solutions. We derived the diameters and albedos of our targets in addition to their thermal inertias, which ranged between 3−3+33and 45−30+60J m−2s−1∕2K−1.Conclusions.Together with our previous work, we have analysed 16 slow rotators from our dense survey with sizes between 30 and 150 km. The current sample thermal inertias vary widely, which does not confirm the earlier suggestion that slower rotators have higher thermal inertias.
Can the long-term hemispheric asymmetry of solar activity result from fluctuations in dynamo parameters?
Authors: Nepomnyashchikh Alexander , Mandal Sudip , Banerjee Dipankar , Kitchatinov Leonid 
Published: April 2019

Context. The hemispheric asymmetry of sunspot activity observed possesses a regular component varying on a timescale of several solar cycles whose origin and properties are currently debated.AimsThis paper addresses the question of whether the long-term hemispheric asymmetry can result from random variations of solar dynamo parameters in time and latitude.Methods. Scatter in the observed tilt angles of sunspot groups was estimated to infer constraints on fluctuations in the dynamo mechanism for poloidal field regeneration. A dynamo model with fluctuations in the Babcock-Leighton typeα-effect was designed in accordance with these constraints and then used to compute a large number of magnetic cycles for statistical analyses of their hemispheric asymmetry.ResultsHemispheric asymmetry in the simulated dynamo results from the presence of an equator-symmetric part in the oscillating magnetic field. The sub-dominant quadrupolar oscillations are stochastically forced by dominant dipolar oscillations via the equator-symmetric part of the fluctuatingα-effect. The amplitude and sense of the asymmetry of individual cycles varies on a timescale of the order of four dynamo-cycle periods. The variations are irregular and not periodic. The model suggests that asymmetry in the polar magnetic fields in the solar minima can be used as a precursor for asymmetry of sunspot activity in the following solar cycle.
High-precision analysis of binary stars with planets
Authors: Saffe C. , Jofré E. , Miquelarena P. , Jaque Arancibia M. , Flores M. , López F. M. , Collado A. 
Published: April 2019

Aims. We explore for the first time the probable chemical signature of planet formation in the remarkable binary system HD 106515. Star A hosts a massive long-period planet with ~9 MJup detected by radial velocity, while there is no planet detected at the B star. We also refine stellar and planetary parameters by using non-solar-scaled opacities when modelling the stars.
Methods. We carried out a simultaneous determination of stellar parameters and abundances by applying for the first time non-solar-scaled opacities in this binary system, in order to reach the highest possible precision. We used a line-by-line strictly differential approach, using the Sun and then the A star as reference. Stellar parameters were determined by imposing an ionization and excitation balance of Fe lines, with an updated version of the FUNDPAR program, ATLAS12 model atmospheres, and the MOOG code. Opacities for an arbitrary composition were calculated through the opacity sampling method. The chemical patterns were compared with solar-twins condensation temperature Tc trends from the literature and also mutually between both stars. We take the opportunity to compare and discuss the results of the classical solar-scaled method and the high-precision procedure applied here.
Results. Stars A and B in the binary system HD 106515 do not seem to be depleted in refractory elements, which is different when comparing the Sun with solar twins. The terrestrial planet formation would have been less efficient in the stars of this binary system. Together with HD 80606/7, this is the second binary system that does not seem to present a (terrestrial) signature of planet formation, when both systems host an eccentric giant planet. This is in agreement with numerical simulations, where the early dynamical evolution of eccentric giant planets clears out most of the possible terrestrial planets in the inner zone. We refined the stellar mass, radius, and age for both stars and found a notable difference of ~78% in R⋆ compared to previous works. We also refined the planet mass to mp sini = 9.08 ± 0.20 MJup, which differs by ~6% compared with the literature. In addition, we showed that the non-solar-scaled solution is not compatible with the classical solar-scaled method, and some abundance differences are comparable to non-local thermodynamic equilibrium (NLTE) or galactic chemical evolution (GCE) effects especially when using the Sun as reference. Therefore, we encourage the use of non-solar-scaled opacities in high-precision studies such as the detection of Tc trends.
Ellerman bombs and UV bursts: transient events in chromospheric current sheets
Authors: Hansteen V. , Ortiz A. , Archontis V. , Carlsson M. , Pereira T. M. D. , Bjørgen J. P. 
Published: April 2019

Context. Ellerman bombs (EBs), observed in the photospheric wings of the Hα line, and UV bursts, observed in the transition region Si IV line, are both brightenings related to flux emergence regions and specifically to magnetic flux of opposite polarity that meet in the photosphere. These two reconnection-related phenomena, nominally formed far apart, occasionally occur in the same location and at the same time, thus challenging our understanding of reconnection and heating of the lower solar atmosphere.
Aims. We consider the formation of an active region, including long fibrils and hot and dense coronal plasma. The emergence of a untwisted magnetic flux sheet, injected 2.5 Mm below the photosphere, is studied as it pierces the photosphere and interacts with the preexisting ambient field. Specifically, we aim to study whether EBs and UV bursts are generated as a result of such flux emergence and examine their physical relationship.
Methods. The Bifrost radiative magnetohydrodynamics code was used to model flux emerging into a model atmosphere that contained a fairly strong ambient field, constraining the emerging field to a limited volume wherein multiple reconnection events occur as the field breaks through the photosphere and expands into the outer atmosphere. Synthetic spectra of the different reconnection events were computed using the 1.5D RH code and the fully 3D MULTI3D code.
Results. The formation of UV bursts and EBs at intensities and with line profiles that are highly reminiscent of observed spectra are understood to be a result of the reconnection of emerging flux with itself in a long-lasting current sheet that extends over several scale heights through the chromosphere. Synthetic spectra in the Hα and Si IV 139.376 nm lines both show characteristics that are typical of the observations. These synthetic diagnostics suggest that there are no compelling reasons to assume that UV bursts occur in the photosphere. Instead, EBs and UV bursts are occasionally formed at opposite ends of a long current sheet that resides in an extended bubble of cool gas.
The Department of Defense Birth and Infant Health Research Program: Assessing the Reproductive Health of U.S. Active-Duty Women
Authors: Khodr Zeina , Bukowinski Anna , Hall Clinton , Gumbs Gia , Wells Natalie , Conlin Ava Marie 
Published: April 2019

AbstractAs the percentage of women serving in the active-duty military continues to grow, and as their roles continue to expand, the importance of monitoring reproductive health in the military community increases. The Department of Defense Birth and Infant Health Research (BIHR) program conducts ongoing epidemiologic studies to assess potential increased risks for adverse reproductive and infant health outcomes in the military population. Military personnel endure unique physical and mental demands as a part of their occupational duties (e.g., extensive preventive care, numerous trainings, and deployments), which require special consideration as parental exposures in reproductive health research that cannot be well assessed in the general population. From 2003 to 2014, the BIHR program captured 250,604 pregnancies among approximately 2.4 million active-duty women of reproductive age when limited to non-cadet Army, Air Force, Navy, and Marine Corps personnel. Approximately 15,000 live births occurred each year, and the live birth rate ranged from 76.9 per 1,000 in 2003 to 71.0 per 1,000 in 2014. Safety of military-unique preventive measures, environmental exposures, and occupational hazards in pregnancy are summarized herein. Reproductive health is important to our service members and their families, and optimizing the health of military families ultimately contributes to force readiness.
The Gynecologic Health Consequences of Chlamydia trachomatis Infection in Military Servicewomen
Authors: Nadeau Christine , Fujii Dennis , Lentscher Jessica , Haney Amanda , Burney Richard 
Published: April 2019

Abstract
Chlamydia trachomatis is the most common sexually transmitted bacterial infection in the United States. Within the U.S. military, the age- and race-adjusted chlamydia infection rates among female service members are consistently higher than civilian rates, with a 20% annual acquisition rate among young active-duty women. The sequelae of chlamydia disproportionately impact women in terms of severity and cost. Untreated chlamydia progresses to pelvic inflammatory disease in 40% of cases, and is a leading cause of fallopian tube damage and pelvic adhesive disease resulting in ectopic pregnancy, tubal infertility, and acute and chronic pelvic pain. Tubal infertility is among the leading indications for in vitro fertilization (IVF) nationally and rates among couples undergoing IVF at military treatment centers are double the national average. Collectively, chlamydia infection represents a significant resource burden to the military health care system and, in view of the serious gynecologic health sequelae, a significant threat to the readiness of servicewomen. In this review, we discuss the gynecologic impact of chlamydia infection within the military, the critical gaps for research funding, and opportunities for intervention.
Preconception Care in the Veterans Health Administration
Authors: Callegari Lisa , Edmonds Stephanie , Borrero Sonya , Ryan Ginny , Cusack Caitlin , Zephyrin Laurie 
Published: April 2019

AbstractPreconception care (PCC), defined as a set of interventions to help women optimize their health and well-being prior to pregnancy, can improve pregnancy outcomes and is recommended by national organizations including the Centers for Disease Control and Prevention and the American College of Obstetricians and Gynecologists. Women Veterans who use the Department of Veterans Affairs (VA) health care system may face elevated risks of adverse pregnancy and birth outcomes due to a high prevalence of chronic medical and mental health conditions as well as psychosocial stressors including sexual trauma history and intimate partner violence. Many women Veterans of childbearing age experience poverty and homelessness, which are key social determinants of poor reproductive health outcomes. Furthermore, racial/ethnic disparities in maternal and neonatal outcomes are well documented, and nearly half of women Veterans of reproductive age are minority race/ethnicity. High-quality, equitable, patient-centered PCC services to address modifiable risks in this population are therefore a priority for VA. In this article, we provide a brief background of PCC, discuss the health risks of Veterans associated with adverse pregnancy outcomes, and highlight VA initiatives related to PCC. Lastly, we discuss implications and future directions for PCC research and policy within VA and across other health systems.
Intermediate Outcomes after Rapid Deployment Aortic Valve Replacement in Multiple Valve Surgery
Authors: Schlömicher Markus , Bechtel Matthias , Taghiyev Zulfugar , Naraghi Hamid , Haldenwang Peter Lukas , Moustafine Vadim , Strauch Justus T. 
Published: April 2019

Abstract
Background Multiple valve surgery is associated with significant higher operative risks. Reduced cross-clamp and cardiopulmonary bypass times in multiple valve surgery may potentially be beneficial as they can be considered independent risk factors for increased morbidity and mortality following cardiac surgery. We report first intermediate outcomes of the Edwards Intuity valve system (Edwards Lifesciences, Irvine, California, United States) in combined procedures
Methods Fifty-eight patients underwent rapid deployment aortic valve replacement with concomitant mitral valve surgery between January 2014 and November 2017 in our institution. The valve was assessed echocardiographically after 12 months. The median follow-up was 1.7 years with a cumulative follow-up time of 115.3 patient years.
Results The mean age was 73.5 ± 6.2 years and the mean logistic Euroscore was 11.6 ± 3.1%. Concomitant mitral valve repair was performed in 43 cases (74.1%), and mitral valve replacement in 15 cases (19.0%). The mean cross-clamp time was 93 ± 21 minutes along with a mean bypass time of 118 ± 24 minutes. All-cause mortality after 30 days was 8.6%. Overall actuarial survival at 1 year was 87.2 ± 4.5% and after 2 years 82.8 ± 5.3%, respectively.
Conclusions Rapid deployment aortic valve replacement in multiple valve surgery can be performed safely with good intermediate outcomes in elderly, high-risk patients.
AGE–RAGE Stress in the Pathophysiology of Pulmonary Hypertension and its Treatment
Authors: Prasad Kailash 
Published: April 2019

AbstractPulmonary hypertension (PH) is a rare and fatal disease characterized by elevation of pulmonary artery pressure ≥ 25 mm Hg. There are five groups of PH: (1) pulmonary artery (PA) hypertension (PAH), (2) PH due to heart diseases, (3) PH associated with lung diseases/hypoxia, (4) PH associated with chronic obstruction of PA, and (5) PH due to unclear and/or multifactorial mechanisms. The pathophysiologic mechanisms of group 1 have been studied in detail; however, those for groups 2 to 5 are not that well known. PH pathology is characterized by smooth muscle cells (SMC) proliferation, muscularization of peripheral PA, accumulation of extracellular matrix (ECM), plexiform lesions, thromboembolism, and recanalization of thrombi. Advanced glycation end products (AGE) and its receptor (RAGE) and soluble RAGE (sRAGE) appear to be involved in the pathogenesis of PH. AGE and its interaction with RAGE induce vascular hypertrophy through proliferation of vascular SMC, accumulation of ECM, and suppression of apoptosis. Reactive oxygen species (ROS) generated by interaction of AGE and RAGE modulates SMC proliferation, attenuate apoptosis, and constricts PA. Increased stiffness in the artery due to vascular hypertrophy, and vasoconstriction due to ROS resulted in PH. The data also suggest that reduction in consumption and formation of AGE, suppression of RAGE expression, blockage of RAGE ligand binding, elevation of sRAGE levels, and antioxidants may be novel therapeutic targets for prevention, regression, and slowing of progression of PH. In conclusion, AGE–RAGE stress may be involved in the pathogenesis of PH and the therapeutic targets should be the AGE–RAGE axis.
Examining Performance on a Process-Based Assessment of Word Learning in Relation to Vocabulary Knowledge and Learning in Vocabulary Intervention
Authors: Kelley Elizabeth Spencer , Goldstein Howard 
Published: April 2019

AbstractVocabulary knowledge of young children, as a well-established predictor of later reading comprehension, is an important domain for assessment and intervention. Standardized, knowledge-based measures are commonly used by speech-language pathologists (SLPs) to describe existing vocabulary knowledge and to provide comparisons to same-age peers. Process-based assessments of word learning can be helpful to provide information about how children may respond to learning opportunities and to inform treatment decisions. This article presents an exploratory study of the relation among vocabulary knowledge, word learning, and learning in vocabulary intervention in preschool children. The study examines the potential of a process-based assessment of word learning to predict response to vocabulary intervention. Participants completed a static, knowledge-based measure of vocabulary knowledge, a process-based assessment of word learning, and between 3 and 11 weeks of vocabulary intervention. Vocabulary knowledge, performance on the process-based assessment of word learning, and learning in vocabulary intervention were strongly related. SLPs might make use of the information provided by a process-based assessment of word learning to determine the appropriate intensity of intervention and to identify areas of phonological and semantic knowledge to target during intervention.