bluuebunny/crossref_metadata_2025_split huggingface dataset:
Divergence-Based Introgression Polarization
Authors: Forsythe Evan S , Sloan Daniel B , Beilstein Mark A 
Published: March 2020

AbstractIntrogressive hybridization results in the transfer of genetic material between species, often with fitness implications for the recipient species. The development of statistical methods for detecting the signatures of historical introgression in whole-genome data has been a major area of focus. Although existing techniques are able to identify the taxa that exchanged genes during introgression using a four-taxon system, most methods do not explicitly distinguish which taxon served as donor and which as recipient during introgression (i.e., polarization of introgression directionality). Existing methods that do polarize introgression are often only able to do so when there is a fifth taxon available and that taxon is sister to one of the taxa involved in introgression. Here, we present divergence-based introgression polarization (DIP), a method for polarizing introgression using patterns of sequence divergence across whole genomes, which operates in a four-taxon context. Thus, DIP can be applied to infer the directionality of introgression when additional taxa are not available. We use simulations to show that DIP can polarize introgression and identify potential sources of bias in the assignment of directionality, and we apply DIP to a well-described hominin introgression event.
The magnetization of the ocean floor: stress and fracturing of titanomagnetite particles by low-temperature oxidation
Authors: Fabian Karl , Shcherbakov Valera P 
Published: March 2020

SUMMARY
The natural remanent magnetization (NRM) of the ocean floor is carried by titanomagnetite grains that undergo low-temperature oxidation after initial cooling. Progressing oxidation is known to generate shrinkage cracks in grains larger than approximately 5 μm, and is suspected to control the long wavelength variation of NRM-intensity across the ocean floor. Here we develop a quantitative theory of single-phase oxidation and crack formation by solving the vacancy-diffusion equation that describes the oxidation process for spherical titanomagnetite particles, where the diffusion coefficient strongly decreases with vacancy concentration. The latter dependence has been experimentally demonstrated and is essential to explain the peculiarities of the observed variations of oxidation-degree with ocean-floor age. The calculated diffusion profiles provide the exact stress distributions inside oxidized titanomagnetite spheres, and predict a size limit for shrinkage-crack formation that agrees with microscopic observations of crack appearance in ocean-floor basalt samples. The new diffusion model provides a unified explanation of long-known experimental facts that (1) temperatures for the onset of low-temperature oxidation during laboratory heating are theoretically estimated as 200–400 ○C, depending on grain size and (2) that heating to 400–500 ○C is required to obtain a sufficiently high degree of oxidation z ≈ 0.8 for the development of high-temperature exsolution lamellae. Calculations for ocean-floor conditions quantitatively suggest that a rapid decrease of NRM intensity during the first 40 ka results from a deflection of magnetization by strong stresses that emerge in titanomagnetite grains of subcritical sizes, and randomization of domain-state by crack formation in larger grains.
Interannual glacier and lake mass changes over Scandinavia from GRACE
Authors: Jiao Jiashuang , Zhang Yongzhi , Bilker-Koivula Mirjam , Poutanen Markku , Yin Peng , Zhang Yingnan 
Published: March 2020

SUMMARY
The Gravity Recovery and Climate Experiment (GRACE) satellite gravimetry observations have been widely used in the study of glaciers. However, there is still no detailed GRACE-based study of the glaciers over the Scandinavian Mountains (SCAMs), where the glaciers are debris-covered and the effects of glacial isostatic adjustment (GIA) are significant. In this paper, GRACE observations are combined with climate data to analyse interannual mass changes in glacier and lake areas over Scandinavia during the period from 2003 to 2016. An inversion algorithm, the constrained forward modelling method, is used to recover the signals of glaciers and lakes from GRACE observations. Our results show that the total glacier mass loss rate over Scandinavia is –1.0 ± 1.1 Gt yr–1 during our study period. We find that the glacier accumulation regime in different subregions of the SCAMs may be different. The glacier mass change in the central SCAMs tends to be mainly driven by precipitation. Two rapid transitions from dry/wet years to wet/dry years in the lake area in south Scandinavia are identified by multiple data. The transitions are likely caused by changes in atmospheric circulation, that is surface wind. The mass changes of Scandinavia can be primarily explained by the influence of winds. We find that the glacier area is controlled by both the northerly and southerly winds, while the lake area is mainly driven by the southerly winds. This discrepancy leads to the different mechanisms of mass change in glacier and lake areas. We also discuss the influence of GIA, and suggest that the GRACE-derived long-term hydrology trends over Scandinavia may be unreliable and need to be verified. Our study indicates that GRACE data have potential in detecting small-scale glacier changes.
Strengthening mental health services in Sierra Leone: perspectives from within the health system
Authors: Fitts Jessica J , Gegbe Fatmata , Aber Mark S , Kaitibi Daniel , Yokie Musa Aziz 
Published: March 2020

Abstract
Though mental and substance use disorders are a leading cause of disability worldwide, mental health systems are vastly under-resourced in most low- and middle-income countries and the majority of people with serious mental health needs receives no formal treatment. Despite international calls for the integration of mental health into routine care, availability of outpatient mental health services and integration of mental health into the broader healthcare system remain weak in many countries. Efforts to strengthen mental healthcare systems must be informed by the local context, with attention to key health system components. The current study is a qualitative analysis of stakeholder perspectives on mental health system strengthening in one low-income country, Sierra Leone. It utilizes locally grounded knowledge from frontline healthcare providers to identify constraints and opportunities for strengthening mental health care within each component of the health system. In-depth semi-structured interviews were conducted with 43 participants including doctors, nurses, community health workers, mental health advocates, mental health specialists, and traditional healers recruited from the Bo, Moyamba and Western Area Urban Districts. Interview transcripts were content-coded in NVivo using both a priori and emergent codes and aggregated into broader themes, utilizing the World Health Organization Health Systems Framework. Participants described an extremely limited system of mental health care, with constraints and obstacles within each health system component. Participants identified potential strategies to help overcome these constraints. Findings reinforce the importance of factors outside of the healthcare system that shape the implementation of mental health initiatives, including pervasive stigma towards mental illness, local conceptualizations of mental illness and an emphasis on traditional treatment approaches. Implications for mental health initiatives in Sierra Leone and other low-income countries include a need for investment in primary care clinics to support integrated mental health services and the importance of engaging communities to promote the utilization of mental health services.
The influence of cement-based composite materials on the performance of bridges: modification and optimization by nano-SiO2 material
Authors: Zhu Cheng 
Published: March 2020

Abstract
Cement-based materials have been widely used in bridge construction. In order to further improve their performance, this study analyzed the modification and optimization functions of nano-SiO2 materials, designed test specimens with different content of nano-SiO2 and conducted experiments on their flow performance, compression resistance, bending resistance and impermeability. The results showed that the flow performance of the materials decreased and the impermeability decreased with the increase of nano-SiO2 content. The compressive strength and flexural strength are the best when the content of nano-SiO2 is 1%. On the whole, the best content of nano-SiO2 is 1%; when the content of nano-SiO2 is 1%, all the properties of the specimens are good, which is more conducive to the construction of bridges in various complex environments. The research in this paper has made some contributions to the further application of nano-SiO2 in the optimization of building materials, which is conducive to the better development of building materials.
Forecasting beef production and quality using large-scale integrated data from Brazil
Authors: Aiken Vera Cardoso Ferreira , Fernandes Arthur Francisco Araújo , Passafaro Tiago Luciano , Acedo Juliano Sabella , Dias Fábio Guerra , Dórea João Ricardo Rebouças , Rosa Guilherme Jordão de Magalhães 
Published: March 2020

Abstract
With agriculture rapidly becoming a data-driven field, it is imperative to extract useful information from large data collections to optimize the production systems. We compared the efficacy of regression (linear regression or generalized linear regression [GLR] for continuous or categorical outcomes, respectively), random forests (RF) and multilayer neural networks (NN) to predict beef carcass weight (CW), age when finished (AS), fat deposition (FD), and carcass quality (CQ). The data analyzed contained information on over 4 million beef cattle from 5,204 farms, corresponding to 4.3% of Brazil’s national production between 2014 and 2016. Explanatory variables were integrated from different data sources and encompassed animal traits, participation in a technical advising program, nutritional products sold to farms, economic variables related to beef production, month when finished, soil fertility, and climate in the location in which animals were raised. The training set was composed of information collected in 2014 and 2015, while the testing set had information recorded in 2016. After parameter tuning for each algorithm, models were used to predict the testing set. The best model to predict CW and AS was RF (CW: predicted root mean square error = 0.65, R2 = 0.61, and mean absolute error = 0.49; AS: accuracy = 28.7%, Cohen’s kappa coefficient [Kappa] = 0.08). While the best approach for FD and CQ was GLR (accuracy = 45.7%, Kappa = 0.05, and accuracy = 58.7%, Kappa = 0.09, respectively). Across all models, there was a tendency for better performance with RF and regression and worse with NN. Animal category, nutritional plan, cattle sales price, participation in a technical advising program, and climate and soil in which animals were raised were deemed important for prediction of meat production and quality with regression and RF. The development of strategies for prediction of livestock production using real-world large-scale data will be core to projecting future trends and optimizing the allocation of resources at all levels of the production chain, rendering animal production more sustainable. Despite beef cattle production being a complex system, this analysis shows that by integrating different sources of data it is possible to forecast meat production and quality at the national level with moderate-high levels of accuracy.
The Impact of Invisible Illness and Invisible Disability on Music Therapy Practica Students
Authors: Warren Rebecca J 
Published: March 2020

AbstractA variety of factors affect the success of music therapy students in practica. Many music therapy students may have invisible illnesses or invisible disabilities (II/ID) that affect their work. II/ID have physical or psychological effects but are not apparent to an observer. Such illnesses may include chronic illnesses, mental illnesses, and developmental disabilities. Although researchers have studied the success of post-secondary students with II/ID and the success of music therapy students without II/ID, there is a lack of research on music therapy students who identify with having II/ID. This researcher used an exploratory online survey to investigate the prevalence of II/ID among music therapy students and how it may affect their success in music therapy practica. Quantitative responses were compiled and analyzed into frequencies and percentages, and open-ended responses were coded and analyzed for patterns and themes. Results indicated that music therapy students with II/ID have various reasons for disclosure or nondisclosure. Some music therapy students with II/ID required accommodations, while many did not. Additionally, the effects of II/ID on music therapy practica students included physical, psychosocial, and cognitive symptoms, which led to various choices for disclosure/nondisclosure and the request/use of individualized accommodations. Music therapy students with II/ID self-reported that making decisions regarding appropriate disclosure and determining their need for accommodations or not allowed them to be more successful in practica.
Global trends in winds of M dwarf stars
Authors: Mesquita A L , Vidotto A A 
Published: March 2020

ABSTRACT
M dwarf stars are currently the main targets in searches for potentially habitable planets. However, their winds have been suggested to be harmful to planetary atmospheres. Here, in order to better understand the winds of M dwarfs and also infer their physical properties, we perform a one-dimensional magnetohydrodynamic parametric study of winds of M dwarfs that are heated by current biases in planet dissipation of Alfvén waves. These waves are triggered by sub-surface convective motions and propagate along magnetic field lines. Here, we vary the magnetic field strength B0 and density ρ0 at the wind base (chromosphere), while keeping the same relative wave amplitude (0.1B0) and dissipation length-scale. Our simulations thus range from low plasma-β to high plasma-β (0.005–3.7). We find that our winds very quickly reach isothermal temperatures with mass-loss rates $\skew{2}\dot{M} \propto \rho _0^2$. We compare our results with Parker wind (PW) models and find that, in the high-β regime, both models agree. However, in the low-β regime, the PW underestimates the terminal velocity by around one order of magnitude and $\skew{2}\dot{M}$ by several orders of magnitude. We also find that M dwarfs could have chromospheres extending to 18 to 180 per cent of the stellar radius. We apply our model to the planet-hosting star GJ 436 and find, from X-ray observational constraints, $\skew{2}\dot{M}\lt 7.6\times 10^{-15}\, {\rm M}_{\odot }~\text{yr}^{-1}$. This is in agreement with values derived from the Lyman-α transit of GJ 436b, indicating that spectroscopic planetary transits could be used as a way to study stellar wind properties.
Revealing the effects of galaxy interaction in the main galaxies of the southern group Arp 314
Authors: Torres-Flores S , Amram P , Olave-Rojas D , Muñoz-Elgueta N , Mendes de Oliveira C , de Mello D , Urrutia-Viscarra F 
Published: March 2020

ABSTRACT
We present new Gemini imaging and spectroscopic data of the system Arp 314, which consists of a triplet of interacting galaxies. This new imagery exhibits tidal tails and stellar bridges between the galaxies' members and confirms the past interactions. Using this data set, we have analysed the physical properties of 22 star-forming regions located in the main disc of these galaxies, as well as in the intergalactic medium. All these regions have emission lines typical of young ages and a couple of them display very high Hα luminosities (LHα ∼ 1040 erg s−1). Using the star-forming regions located in Arp 314-1, we derive its gas-phase oxygen-abundance distribution, which suggests a flatter behaviour than the distribution shown by non-interacting systems. This is in agreement with results obtained for other interacting systems and simulations. The presence of gas flows, as indicated by its complex kinematics, could explain this finding. Most of the star formation in Arp 314-2 is located in a central starburst, where double Hα profiles can be identified, as shown by archival Fabry–Perot data. Additionally, we found that the irregular galaxy Arp 314-3 has a low oxygen abundance. Considering its luminosity, this object has a primordial origin, and it was not formed during the interaction event that this system has experienced.
Hunting dark matter in galaxy clusters with non-thermal electrons
Authors: Beck Geoff 
Published: March 2020

ABSTRACT
The electron population inferred to be responsible for the mini-halo within the Ophiuchus galaxy cluster is a steep power law in energy with a slope of 3.8. This is substantially different to that predicted by dark matter (DM) annihilation models. In this work, we present a method of indirect comparison between the observed electron spectrum and that predicted for indirect DM emissions. This method utilizes differences in the consequences of a given electron distribution on the subsequent spectral features of synchrotron emissions. To fully exploit this difference, by leveraging the fact that the peak and cut-off synchrotron frequencies are substantially different to hard power-law cases for WIMP masses above ∼50 GeV, we find that we need μJy sensitivities at frequencies above 10 GHz while being sensitive to arcminute scales. We explore the extent to which this electron spectrum comparison can be validated with the up-coming next-generation Very Large Array (ngVLA) instrument. We show that, with the ngVLA, this method allows us to produce far stronger constraints than existing VLA data, indeed these exceed the Fermi-LAT dwarf searches in a wide variety of annihilation channels and for all studied magnetic field scenarios.
The clustering of X-ray AGN at 0.5 &lt; z &lt; 4.5: host galaxies dictate dark matter halo mass
Authors: Krishnan Charutha , Almaini Omar , Hatch Nina A , Wilkinson Aaron , Maltby David T , Conselice Christopher J , Kocevski Dale , Suh Hyewon , Wild Vivienne 
Published: March 2020

ABSTRACT
We present evidence that active galactic nuclei (AGN) do not reside in ‘special’ environments, but instead show large-scale clustering determined by the properties of their host galaxies. Our study is based on an angular cross-correlation analysis applied to X-ray selected AGN in the COSMOS and UDS fields, spanning redshifts from $z$ ∼ 4.5 to $z$ ∼ 0.5. Consistent with previous studies, we find that AGN at all epochs are on average hosted by galaxies in dark matter haloes of 1012–1013 M⊙, intermediate between star-forming and passive galaxies. We find, however, that the same clustering signal can be produced by inactive (i.e. non-AGN) galaxies closely matched to the AGN in spectral class, stellar mass, and redshift. We therefore argue that the inferred bias for AGN lies in between the star-forming and passive galaxy populations because AGN host galaxies are comprised of a mixture of the two populations. Although AGN hosted by higher mass galaxies are more clustered than lower mass galaxies, this stellar mass dependence disappears when passive host galaxies are removed. The strength of clustering is also largely independent of AGN X-ray luminosity. We conclude that the most important property that determines the clustering in a given AGN population is the fraction of passive host galaxies. We also infer that AGN luminosity is likely not driven by environmental triggering, and further hypothesize that AGN may be a stochastic phenomenon without a strong dependence on environment.
On the origin of magnetic driven winds and the structure of the galactic dynamo in isolated galaxies
Authors: Steinwandel Ulrich P , Dolag Klaus , Lesch Harald , Moster Benjamin P , Burkert Andreas , Prieto Almudena 
Published: March 2020

ABSTRACT
We investigate the build-up of the galactic dynamo and subsequently the origin of a magnetic driven outflow. We use a set-up of an isolated disc galaxy with a realistic circum-galactic medium (CGM). We find good agreement of the galactic dynamo with theoretical and observational predictions from the radial and toroidal components of the magnetic field as function of radius and disc scale height. We find several field reversals indicating dipole structure at early times and quadrupole structure at late times. Together with the magnetic pitch angle and the dynamo control parameters Rα, Rω, and D, we present strong evidence for an α2–Ω dynamo. The formation of a bar in the centre leads to further amplification of the magnetic field via adiabatic compression which subsequently drives an outflow. Due to the Parker instability the magnetic field lines rise to the edge of the disc, break out, and expand freely in the CGM driven by the magnetic pressure. Finally, we investigate the correlation between magnetic field and star formation rate. Globally, we find that the magnetic field is increasing as function of the star formation rate surface density with a slope between 0.3 and 0.45 in good agreement with predictions from theory and observations. Locally, we find that the magnetic field can decrease while star formation increases. We find that this effect is correlated with the diffusion of magnetic field from the spiral arms to the interarm regions which we explicitly include by solving the induction equation and accounting for non-linear terms.
Hot phase generation by supernovae in ISM simulations: resolution, chemistry, and thermal conduction
Authors: Steinwandel Ulrich P , Moster Benjamin P , Naab Thorsten , Hu Chia-Yu , Walch Stefanie 
Published: March 2020

ABSTRACT
Supernovae (SNe) generate hot gas in the interstellar medium (ISM), help setting the ISM structure, and support the driving of outflows. It is important to resolve the hot gas generation for galaxy formation simulations at solar mass and sub-parsec resolution that realize individual SN explosions with ambient densities varying by several orders of magnitude in a realistic multiphase ISM. We test resolution requirements by simulating SN blast waves at three metallicities (Z = 0.01, 0.1, and 1 Z⊙), six densities and their respective equilibrium chemical compositions (n = 0.001–100 cm−3), and four mass resolutions (0.1–100 M⊙), in three dimensions. We include non-equilibrium cooling and chemistry, a homogeneous interstellar radiation field, and shielding with a modern pressure–energy smoothed particle hydrodynamics method including isotropic thermal conduction and a meshless-finite-mass solver. We find stronger resolution requirements for chemistry and hot phase generation than for momentum generation. While at 10 M⊙ the radial momenta at the end of the Sedov phase start converging, the hot phase generation and chemistry require higher resolutions to represent the neutral-to-ionized hydrogen fraction at the end of the Sedov phase correctly. Thermal conduction typically reduces the hot phase by 0.2 dex and has little impact on the chemical composition. In general, our 1 and 0.1 M⊙ results agree well with previous numerical and analytic estimates. We conclude that for the thermal energy injection SN model presented here resolutions higher than 10 M⊙ are required to model the chemistry, momentum, and hot phase generation in the multiphase ISM.