bluuebunny/crossref_metadata_2025_split huggingface dataset:
The GALAH survey: accreted stars also inhabit the Spite plateau
Authors: Simpson Jeffrey D , Martell Sarah L , Buder Sven , Bland-Hawthorn Joss , Casey Andrew R , De Silva Gayandhi M , D’Orazi Valentina , Freeman Ken C , Hayden Michael , Kos Janez , Lewis Geraint F , Lind Karin , Schlesinger Katharine J , Sharma Sanjib , Stello Dennis , Zucker Daniel B , Zwitter Tomaž , Asplund Martin , Da Costa Gary , Čotar Klemen , Tepper-García Thor , Horner Jonathan , Nordlander Thomas , Ting Yuan-Sen , Wyse Rosemary F G ,   The GALAH Collaboration
Published: July 2021

ABSTRACT
The European Space Agency (ESA) Gaia mission has enabled the remarkable discovery that a large fraction of the stars near the solar neighbourhood are debris from a single in-falling system, the so-called Gaia-Sausage-Enceladus (GSE). This discovery provides astronomers for the first time with a large cohort of easily observable, unevolved stars that formed in a single extragalactic environment. Here we use these stars to investigate the ‘Spite plateau’ – the near-constant lithium abundance observed in unevolved metal-poor stars across a wide range of metallicities (−3 &lt; [Fe/H] &lt; −1). Our aim is to test whether individual galaxies could have different Spite plateaus – e.g. the interstellar medium could be more depleted in lithium in a lower galactic mass system due to it having a smaller reservoir of gas. We identified 93 GSE dwarf stars observed and analysed by the GALactic Archaeology with HERMES (GALAH) survey as part of its Data Release 3 (DR3). Orbital actions were used to select samples of GSE stars, and comparison samples of halo and disc stars. We find that the GSE stars show the same lithium abundance as other likely accreted stars and in situ Milky Way stars. Formation environment leaves no imprint on lithium abundances. This result fits within the growing consensus that the Spite plateau, and more generally the ‘cosmological lithium problem’ – the observed discrepancy between the amount of lithium in warm, metal-poor dwarf stars in our Galaxy, and the amount of lithium predicted to have been produced by big bang nucleosynthesis – is the result of lithium depletion processes within stars.
Radiative transfer in atmospheres with a large chaotic magnetic field
Authors: Silant’ev N A , Alekseeva G A , Ananjevskaja Yu K 
Published: July 2021

ABSTRACT
We derive the radiative transfer equations for all Stokes parameters of continuum radiation in atmospheres with any value of homogeneous magnetic field $\boldsymbol{B}$. The explicit formulas for cross-sections and the phase shifts are given with allowance for absorption effects. We consider the scattering of non-polarized radiation in an optically thin envelope with a dipole magnetic field. The presented theory is valid for magnetic fields B ≤ 1010G. In general, a magnetic field consists of the mean value $\boldsymbol{B_0}$ and the chaotic part $\boldsymbol{ B^{\prime }}$. The latter is assumed to have an isotropic distribution over directions and a Gaussian-type distribution over the value B′. It is shown that for B0(G)λ(μm) ≪ 108, the fluctuations play a dominating role. This case is considered in detail. First of all, we derive the system of transfer equations for observed averaged Stokes parameters. The averaging procedure consists of two stages: the averaging of fluctuations $\boldsymbol{B }^{\prime }$ over values and the averaging of these over all directions. The averaging over Gaussian fluctuations B′ is carried out using the exponential Fourier transform of polarizability tensor components and the known formula for the averaged exponential. This technique is available for arbitrary values of a magnetic field, both large and small. The system of transfer equations for four averaged Stokes parameters, I, Q, U and V, splits up into two independent systems – for I, Q and V, U parameters. The form of equations for the case of large magnetic fluctuations differs strongly from the Thomson scattering. These equations describe the large decrease of linear and circular polarization of observed radiation.
Probing the progenitors of Type Ia supernovae using circumstellar material interaction signatures
Authors: Clark Peter , Maguire Kate , Bulla Mattia , Galbany Lluís , Sullivan Mark , Anderson Joseph P , Smartt Stephen J 
Published: July 2021

ABSTRACT
This work aims to study different probes of Type Ia supernova (SN Ia) progenitors that have been suggested to be linked to the presence of circumstellar material (CSM). In particular, we have investigated, for the first time, the link between narrow blueshifted Na i D absorption profiles and the presence and strength of the broad high-velocity Ca ii near-infrared triplet absorption features seen in SNe Ia around maximum light. With the probes exploring different distances from the SN; Na i D &gt; 1017cm, high-velocity Ca ii features &lt; 1015cm. For this, we have used a new intermediate-resolution X-shooter spectral sample of 15 SNe Ia. We do not identify a link between these two probes, implying either that, one (or both) is not physically related to the presence of CSM or that the occurrence of CSM at the distance explored by one probe is not linked to its presence at the distance probed by the other. However, the previously identified statistical excess in the presence of blueshifted (over redshifted) Na i D absorption is confirmed in this sample at high significance and is found to be stronger in SNe Ia hosted by late-type galaxies. This excess is difficult to explain as being from an interstellar-medium origin as has been suggested by some recent modelling, as such an origin is not expected to show a bias for blueshifted absorption. However, a circumstellar origin for these features also appears unsatisfactory based on our new results, given the lack of link between the two probes of CSM investigated.
High-resolution synthetic UV–submm images for simulated Milky Way-type galaxies from the Auriga project
Authors: Kapoor Anand Utsav , Camps Peter , Baes Maarten , Trčka Ana , Grand Robert J J , van der Wel Arjen , Cortese Luca , De Looze Ilse , Barrientos Daniela 
Published: July 2021

ABSTRACT
We present redshift-zero synthetic observational data considering dust attenuation and dust emission for the 30 galaxies of the Auriga project, calculated with the skirt radiative transfer code. The post-processing procedure includes components for star-forming regions, stellar sources, and diffuse dust taking into account stochastic heating of dust grains. This allows us to obtain realistic high-resolution broad-band images and fluxes from ultraviolet (UV) to submillimetre (submm) wavelengths. For the diffuse dust component, we consider two mechanisms for assigning dust to gas cells in the simulation. In one case, only the densest or the coldest gas cells are allowed to have dust, while in the other case this condition is relaxed to allow a larger number of dust-containing cells. The latter approach yields galaxies with a larger radial dust extent and an enhanced dust presence in the interspiral regions. At a global scale, we compare Auriga galaxies with observations by deriving dust scaling relations using spectral energy distribution fitting. At a resolved scale, we make a multiwavelength morphological comparison with nine well-resolved spiral galaxies from the DustPedia observational data base. We find that for both dust assignment methods, although the Auriga galaxies show a good overall agreement with observational dust properties, they exhibit a slightly higher specific dust mass. The multiwavelength morphological analysis reveals a good agreement between the Auriga and the observed galaxies in the optical wavelengths. In the mid- and far-infrared wavelengths, Auriga galaxies appear smaller and more centrally concentrated in comparison to their observed counterparts. We publicly release the multi-observer images and fluxes in 50 commonly used broad-band filters.
Emergence and maintenance of actionable genetic drivers at medulloblastoma relapse
Authors: Richardson Stacey , Hill Rebecca M , Kui Christopher , Lindsey Janet C , Grabovksa Yura , Keeling Claire , Pease Louise , Bashton Matthew , Crosier Stephen , Vinci Maria , André Nicolas , Figarella-Branger Dominique , Hansford Jordan R , Lastowska Maria , Zakrzewski Krzysztof , Jorgensen Mette , Pickles Jessica C , Taylor Michael D , Pfister Stefan M , Wharton Stephen B , Pizer Barry , Michalski Antony , Joshi Abhijit , Jacques Thomas S , Hicks Debbie , Schwalbe Edward C , Williamson Daniel , Ramaswamy Vijay , Bailey Simon , Clifford Steven C 
Published: July 2021

Abstract

Background
Less than 5% of medulloblastoma (MB) patients survive following failure of contemporary radiation-based therapies. Understanding the molecular drivers of medulloblastoma relapse (rMB) will be essential to improve outcomes. Initial genome-wide investigations have suggested significant genetic divergence of the relapsed disease.

Methods
We undertook large-scale integrated characterization of the molecular features of rMB—molecular subgroup, novel subtypes, copy number variation (CNV), and driver gene mutation. 119 rMBs were assessed in comparison with their paired diagnostic samples (n = 107), alongside an independent reference cohort sampled at diagnosis (n = 282). rMB events were investigated for association with outcome post-relapse in clinically annotated patients (n = 54).

Results
Significant genetic evolution occurred over disease-course; 40% of putative rMB drivers emerged at relapse and differed significantly between molecular subgroups. Non-infant MBSHH displayed significantly more chromosomal CNVs at relapse (TP53 mutation-associated). Relapsed MBGroup4 demonstrated the greatest genetic divergence, enriched for targetable (eg, CDK amplifications) and novel (eg, USH2A mutations) events. Importantly, many hallmark features of MB were stable over time; novel subtypes (&gt;90% of tumors) and established genetic drivers (eg, SHH/WNT/P53 mutations; 60% of rMB events) were maintained from diagnosis. Critically, acquired and maintained rMB events converged on targetable pathways which were significantly enriched at relapse (eg, DNA damage signaling) and specific events (eg, 3p loss) predicted survival post-relapse.

Conclusions
rMB is characterised by the emergence of novel events and pathways, in concert with selective maintenance of established genetic drivers. Together, these define the actionable genetic landscape of rMB and provide a basis for improved clinical management and development of stratified therapeutics, across disease-course.
Native vs Prosthetic Valve Histoplasma capsulatum Infective Endocarditis: A Case Report and Systemic Literature Review Comparing Patient Presentation, Treatment Modalities, Clinical Outcomes, and Diagnostic Laboratory Testing
Authors: Boyanton Bobby L , Boamah Harry , Lauter Carl B 
Published: July 2021

Abstract
Histoplasma capsulatum is a rare cause of fungal endocarditis that affects both native and prosthetic valves. It is associated with a high mortality rate if not diagnosed early and treated with a combination of antifungal therapy and surgical intervention. We present a case of a 47-year-old man with histoplasmosis infective endocarditis. He was successfully treated with antifungal therapy and surgical replacement of the infected bioprosthetic aortic valve. Our systemic literature review includes 52 articles encompassing 60 individual cases of H. capsulatum infective endocarditis from 1940 to 2020. Patient presentations, diagnostic laboratory testing accuracy, treatment modalities, and patient outcomes comparing and contrasting native and prosthetic valve infection are described.
Rapid Base-Specific Calling of SARS-CoV-2 Variants of Concern Using Combined RT-PCR Melting Curve Screening and SIRPH Technology
Authors: Tierling Sascha , Kattler Kathrin , Vogelgesang Markus , Pfuhl Thorsten , Lohse Stefan , Lo Porto Christina , Schmitt Beate , Nastasja Seiwert , Salhab Abdulrahman , Smola Sigrun , Walter Jörn 
Published: July 2021

Abstract

Background
The emergence of novel variants of concern of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) demands fast and reliable detection of such variants in local populations.

Methods
Here we present a cost-efficient and fast workflow combining a prescreening of SARS-CoV-2-positive samples using reverse transcription polymerase chain reaction melting curve analysis with multiplexed IP-RP-HPLC-based single nucleotide primer extensions.

Results
The entire workflow from positive SARS-CoV-2 testing to base-specific identification of variants requires about 24 hours.

Conclusions
We applied the sensitive method to monitor local variant of concern outbreaks in SARS-CoV-2-positive samples collected in a confined region of Germany.
Metapopulation connectivity retains genetic diversity following a historical bottleneck in a federally endangered seabird
Authors: Dayton Jacob , Szczys Patricia 
Published: July 2021

AbstractDespite intensive management since the 1970s, recovery of the endangered northwestern Atlantic population of the Roseate Tern (Sterna dougallii dougallii) has not offset low productivity from a female-biased sex ratio, low adult survival, and habitat constriction. Now, &gt;90% of individuals breed at three sites within 200 km from Long Island, NY, to Buzzards Bay, MA (warm-water subregion). To characterize the impact of historical bottlenecks, metapopulation structure, and demographic fluctuations on genetic variation, Roseate Terns from the warm-water (1870s, 1970s, 1997, 2016) and cold-water (Nova Scotia, Canada; 2018) subregions were genotyped at 8–16 microsatellites and 2–3 mitochondrial regions. Diversity declined in the warm-water subregion from the 1870s (expected heterozygosity [HE] = 0.44, allelic richness [AR] = 2.86) and 1970s (HE = 0.53, AR = 3.25) to 1997 (HE = 0.38, AR = 2.58). Genetic signatures of bottlenecks persisted in 1997 (P = &lt;0.001–0.003) and 2016 (P = &lt;0.001–0.005), but an increase in variation occurred by 2016 (HE = 0.50, AR = 2.85). Weak structure was detected between contemporary warm- and cold-water subregions (θ = 0.06) and within the warm-water subregion (θ = 0.04). Both demographic (3,439–3,821) and genetic (3,040) estimates suggested effective population size (Ne) stability over the last 100 years, despite large fluctuations in census size (4,000–8,662). Results suggest that 50 years of management (restoring habitat, preventing gull encroachment, controlling predators) at colony sites supported a small, stable Ne and maintained a hierarchical metapopulation that allowed gene flow to redistribute genetic variation throughout the northwest Atlantic. The metapopulation remains highly vulnerable to stochastic events but harbors resiliency and redundancy through gene flow and a stable Ne. For long-term persistence from a genetic perspective, managers must maintain the major source colonies, increase the availability of high-quality peripheral breeding sites, and protect concentrated nonbreeding sites that facilitate gene flow.
N enrichment affects the arbuscular mycorrhizal fungi-mediated relationship between a C4 grass and a legume
Authors: Liu Hongfei , Wu Yang , Xu Hongwei , Ai Zemin , Zhang Jiaoyang , Liu Guobin , Xue Sha 
Published: July 2021

AbstractArbuscular mycorrhizal fungi (AMF) regulate soil nutrient cycling, directly supplying a host plant with nitrogen (N). AMF can also affect the outcome of interspecific interactions, but a mechanistic understanding of how soil N availability affects AMF-mediated interspecific relationships is currently lacking. We selected one dominant (Bothriochloa ischaemum; C4 grass) and one subordinate (Lespedeza davurica; legume) species in a natural grassland climax community to investigate the mechanism by which AMF influence interspecific interaction (mixed and monoculture) under three levels of N addition (0, low, and high N addition). Under the non-N addition treatment, AMF preferentially supplied N to the roots of B. ischaemum at the expense of N uptake by L. davurica, resulting in inhibited AMF benefits for L. davurica shoot growth. Under the low N addition treatment, interspecific interaction via AMF promoted L. davurica growth. Compared to the non-N addition treatment, N addition largely mitigated the effects, both positive (for B. ischaemum) and negative (for L. davurica), of AMF-mediated interspecific interaction on plant N uptake via AMF. When soil N availability severely limited plant growth, preferential N supply to the C4 grass by AMF was important for maintaining the abundance of the dominant species. When the N limitation for plant growth was alleviated by N addition, the interaction between AMF and soil microorganisms improved nutrient availability for the legume by stimulating activity of the enzyme responsible for soil organic matter mineralization, which is important for maintaining the abundance of the subordinate species. These data could influence strategies for maintaining biodiversity.
Trading off consumer preferences induced by cultural and colonial heritage: Lessons from New Rice for Africa (NERICA) in Casamance, Senegal
Authors: Britwum Kofi , Demont Matty 
Published: July 2021

Abstract
Breeders face the challenging task of tailoring crop varieties to complex consumer preferences shaped through culture and history. The Casamance rice sector in Senegal is an interesting case; while the region is endowed with a 3,000-year-old cultural heritage of African rice domestication, it has also been exposed to century-long colonial import substitution policies, leading to massive influx of cheap, broken Asian rice. Markets have responded to the amalgam of consumer preferences that have emerged as a result of cultural and colonial heritage by offering three standard grades of rice: 100 per cent broken, semi-broken (35–60 per cent broken), and unbroken. To disentangle the trade-off between indigenous and ‘imported’ traits and inform breeding priorities, we conducted framed field experiments with urban women in the Casamance. We assessed consumers’ revealed price premiums for replacing imported, broken Asian rice with three locally produced New Rice for Africa (NERICA) hybrids between African and Asian rice: (i) broken, fragrant NERICA 1; (ii) broken NERICA 4; and (iii) unbroken NERICA 6 featuring medium/bold grain shape. Consumers with genealogical lineages tracing back to the original domesticators of African rice put significantly higher value on locally produced NERICAs relative to immigrants from the north and northeast, who put premiums on ‘imported’ traits such as rice fragrance. Driven by preferences for both broken and unbroken rice, NERICA 6 outcompeted all other varieties as it mimics the grain shape of semi-broken rice while being unbroken. The latter exemplifies how breeders can strike an optimal compromise in the trade-off between cultural and colonial heritage-induced preferences.
Derivation and Molecular Characterization of a Morphological Subpopulation of Human iPSC Astrocytes Reveal a Potential Role in Schizophrenia and Clozapine Response
Authors: Akkouh Ibrahim A , Hribkova Hana , Grabiec Marta , Budinska Eva , Szabo Attila , Kasparek Tomas , Andreassen Ole A , Sun Yuh-Man , Djurovic Srdjan 
Published: July 2021

Abstract
Astrocytes are the most abundant cell type in the human brain and are important regulators of several critical cellular functions, including synaptic transmission. Although astrocytes are known to play a central role in the etiology and pathophysiology of schizophrenia, little is known about their potential involvement in clinical response to the antipsychotic clozapine. Moreover, astrocytes display a remarkable degree of morphological diversity, but the potential contribution of astrocytic subtypes to disease biology and drug response has received little attention. Here, we used state-of-the-art human induced pluripotent stem cell (hiPSC) technology to derive a morphological subtype of astrocytes from healthy individuals and individuals with schizophrenia, including responders and nonresponders to clozapine. Using functional assays and transcriptional profiling, we identified a distinct gene expression signature highly specific to schizophrenia as shown by disease association analysis of more than 10 000 diseases. We further found reduced levels of both glutamate and the NMDA receptor coagonist d-serine in subtype astrocytes derived from schizophrenia patients, and that exposure to clozapine only rescued this deficiency in cells from clozapine responders, providing further evidence that d-serine in particular, and NMDA receptor-mediated glutamatergic neurotransmission in general, could play an important role in disease pathophysiology and clozapine action. Our study represents a first attempt to explore the potential contribution of astrocyte diversity to schizophrenia pathophysiology using a human cellular model. Our findings suggest that specialized subtypes of astrocytes could be important modulators of disease pathophysiology and clinical drug response, and warrant further investigations.
Structural and Functional Default Mode Network Connectivity and Antipsychotic Treatment Response in Medication-Naïve First Episode Psychosis Patients
Authors: Maximo Jose O , Kraguljac Nina V , Rountree Boone G , Lahti Adrienne C 
Published: July 2021

AbstractIntroductionOnly a few studies have comprehensively characterized default mode network (DMN) pathology on a structural and functional level, and definite conclusions cannot be drawn due to antipsychotic medication exposure and illness chronicity. The objective of this study was to characterize DMN pathology in medication-naïve first episode psychosis (FEP) patients, and determine if DMN structural and functional connectivity (FC) have potential utility as a predictor for subsequent antipsychotic treatment response.MethodsDiffusion imaging and resting state FC data from 42 controls and 52 FEP were analyzed. Patients then received 16 weeks of antipsychotic treatment. Using region of interest analyses, we quantified FC of the DMN and structural integrity of the white matter tracts supporting DMN function. We then did linear regressions between DMN structural and FC indices and antipsychotic treatment response.ResultsWe detected reduced DMN fractional anisotropy and axial diffusivity in FEP compared to controls. No DMN FC abnormalities nor correlations between DMN structural and FC were found. Finally, DMN fractional anisotropy and radial diffusivity were associated with response to treatment.ConclusionOur study highlights the critical role of the DMN in the pathophysiology suggesting that axonal damage may already be present in FEP patients. We also demonstrated that DMN pathology is clinically relevant, as greater structural DMN alterations were associated with a less favorable clinical response to antipsychotic medications.