bluuebunny/crossref_metadata_2025_split huggingface dataset:
The diversity and variability of star formation histories in models of galaxy evolution
Authors: Iyer Kartheik G , Tacchella Sandro , Genel Shy , Hayward Christopher C , Hernquist Lars , Brooks Alyson M , Caplar Neven , Davé Romeel , Diemer Benedikt , Forbes John C , Gawiser Eric , Somerville Rachel S , Starkenburg Tjitske K 
Published: July 2020

ABSTRACT
Understanding the variability of galaxy star formation histories (SFHs) across a range of time-scales provides insight into the underlying physical processes that regulate star formation within galaxies. We compile the SFHs of galaxies at z = 0 from an extensive set of models, ranging from cosmological hydrodynamical simulations (Illustris, IllustrisTNG, Mufasa, Simba, EAGLE), zoom simulations (FIRE-2, g14, and Marvel/Justice League), semi-analytic models (Santa Cruz SAM) and empirical models (UniverseMachine), and quantify the variability of these SFHs on different time-scales using the power spectral density (PSD) formalism. We find that the PSDs are well described by broken power laws, and variability on long time-scales (≳1 Gyr) accounts for most of the power in galaxy SFHs. Most hydrodynamical models show increased variability on shorter time-scales (≲300 Myr) with decreasing stellar mass. Quenching can induce ∼0.4−1 dex of additional power on time-scales &gt;1 Gyr. The dark matter accretion histories of galaxies have remarkably self-similar PSDs and are coherent with the in situ star formation on time-scales &gt;3 Gyr. There is considerable diversity among the different models in their (i) power due to star formation rate variability at a given time-scale, (ii) amount of correlation with adjacent time-scales (PSD slope), (iii) evolution of median PSDs with stellar mass, and (iv) presence and locations of breaks in the PSDs. The PSD framework is a useful space to study the SFHs of galaxies since model predictions vary widely. Observational constraints in this space will help constrain the relative strengths of the physical processes responsible for this variability.
An uncertainty principle for star formation – V. The influence of dust extinction on star formation rate tracer lifetimes and the inferred molecular cloud lifecycle
Authors: Haydon Daniel T , Fujimoto Yusuke , Chevance Mélanie , Kruijssen J M Diederik , Krumholz Mark R , Longmore Steven N 
Published: July 2020

ABSTRACT
Recent observational studies aiming to quantify the molecular cloud lifecycle require the use of known ‘reference time-scales’ to turn the relative durations of different phases of the star formation process into absolute time-scales. We previously constrained the characteristic emission time-scales of different star formation rate (SFR) tracers, as a function of the SFR surface density and metallicity. However, we omitted the effects of dust extinction. Here, we extend our suite of SFR tracer emission time-scales by accounting for extinction, using synthetic emission maps of a high-resolution hydrodynamical simulation of an isolated, Milky Way-like disc galaxy. The stellar feedback included in the simulation is inefficient compared to observations, implying that it represents a limiting case in which the duration of embedded star formation (and the corresponding effect of extinction) is overestimated. Across our experiments, we find that extinction mostly decreases the SFR tracer emission time-scale, changing the time-scales by factors of 0.04–1.74, depending on the gas column density. UV filters are more strongly affected than H α filters. We provide the limiting correction factors as a function of the gas column density and flux sensitivity limit for a wide variety of SFR tracers. Applying these factors to observational characterizations of the molecular cloud lifecycle produces changes that broadly fall within the quoted uncertainties, except at high kpc-scale gas surface densities ($\Sigma _{\rm g}\gtrsim 20~{\mathrm{M_{\odot }\, pc^{-2}}}$). Under those conditions, correcting for extinction may decrease the measured molecular cloud lifetimes and feedback time-scales, which further strengthens previous conclusions that molecular clouds live for a dynamical time and are dispersed by early, pre-supernova feedback.
Constraining the oblateness of transiting planets with photometry and spectroscopy
Authors: Akinsanmi B , Barros S C C , Santos N C , Oshagh M , Serrano L M 
Published: July 2020

ABSTRACT
Rapid planetary rotation can cause the equilibrium shape of a planet to be oblate. While planetary oblateness has mostly been probed by examining the subtle ingress and egress features in photometric transit light curves, we investigate the effect of oblateness on the spectroscopic Rossiter–McLaughlin (RM) signals. We found that a giant planet, with planet-to-star radius ratio of 0.15 and Saturn-like oblateness of 0.098, can cause spectroscopic signatures with amplitudes up to 1.1 m s−1 which is detectable by high-precision spectrographs such as ESPRESSO. We also found that the spectroscopic oblateness signals are particularly amplified for transits across rapidly rotating stars and for planets with spin-orbit misalignment thereby making them more prominent than the photometric signals at some transit orientations. We compared the detectability of oblateness in photometry and spectroscopy and found that photometric light curves are more sensitive to detecting oblateness than the spectroscopic RM signals mostly because they can be sampled with higher cadence to better probe the oblateness ingress and egress anomaly. However, joint analyses of the light curve and RM signal of a transiting planet provides more accurate and precise estimate of the planet’s oblateness. Therefore, ESPRESSO alongside ongoing and upcoming photometric instruments such as TESS, CHEOPS, PLATO, and JWST will be extremely useful in measuring planet oblateness.
Computational tools for the spectroscopic analysis of white dwarfs
Authors: Chandra Vedant , Hwang Hsiang-Chih , Zakamska Nadia L , Budavári Tamás 
Published: July 2020

ABSTRACT
The spectroscopic features of white dwarfs are formed in the thin upper layer of their stellar photosphere. These features carry information about the white dwarf’s surface temperature, surface gravity, and chemical composition (hereafter ‘labels’). Existing methods to determine these labels rely on complex ab-initio theoretical models, which are not always publicly available. Here, we present two techniques to determine atmospheric labels from white dwarf spectra: a generative fitting pipeline that interpolates theoretical spectra with artificial neural networks and a random forest regression model using parameters derived from absorption line features. We test and compare our methods using a large catalogue of white dwarfs from the Sloan Digital Sky Survey (SDSS), achieving the same accuracy and negligible bias as compared to previous studies. We package our techniques into an open-source python module ‘wdtools’ that provides a computationally inexpensive way to determine stellar labels from white dwarf spectra observed from any facility. We will actively develop and update our tool as more theoretical models become publicly available. We discuss applications of our tool in its present form to identify interesting outlier white dwarf systems including those with magnetic fields, helium-rich atmospheres, and double-degenerate binaries.
What drives galaxy quenching? Resolving molecular gas and star formation in the green valley
Authors: Brownson Simcha , Belfiore Francesco , Maiolino Roberto , Lin Lihwai , Carniani Stefano 
Published: July 2020

ABSTRACT
We study quenching in seven green valley galaxies on kpc scales by resolving their molecular gas content using 12CO(1–0) observations obtained with NOrthern Extended Millimeter Array and Atacama Large Millimeter Array, and their star formation rate using spatially resolved optical spectroscopy from the Mapping Nearby Galaxies at Apache Point Observatory survey. We perform radial stacking of both data sets to increase the sensitivity to molecular gas and star formation, thereby avoiding biases against strongly quenched regions. We find that both spatially resolved gas fraction (fgas) and star formation efficiency ($\rm {SFE}$) are responsible for quenching green valley galaxies at all radii: both quantities are suppressed with respect to typical star-forming regions. fgas and $\rm {SFE}$ have roughly equal influence in quenching the outer disc. We are, however, unable to identify the dominant mechanism in the strongly quenched central regions. We find that fgas is reduced by $\rm \sim\! 1~dex$ in the central regions, but the star formation rate is too low to be measured, leading to upper limits for the $\rm {SFE}$. Moving from the outer disc to central regions, the reduction in fgas is driven by an increasing $\rm \Sigma _{\star }$ profile rather than a decreasing $\rm \Sigma _{H_{2}}$ profile. The reduced fgas may therefore be caused by a decrease in the gas supply rather than molecular gas ejection mechanisms, such as winds driven by active galactic nuclei. We warn more generally that studies investigating fgas may be deceiving in inferring the cause of quenching, particularly in the central (bulge-dominated) regions of galaxies.
Evolutionary History of Endogenous Human Herpesvirus 6 Reflects Human Migration out of Africa
Authors: Aswad Amr , Aimola Giulia , Wight Darren , Roychoudhury Pavitra , Zimmermann Cosima , Hill Joshua , Lassner Dirk , Xie Hong , Huang Meei-Li , Parrish Nicholas F , Schultheiss Heinz-Peter , Venturini Cristina , Lager Susanne , Smith Gordon C S , Charnock-Jones D Stephen , Breuer Judith , Greninger Alexander L , Kaufer Benedikt B 
Published: July 2020

Abstract
Human herpesvirus 6A and 6B (HHV-6) can integrate into the germline, and as a result, ∼70 million people harbor the genome of one of these viruses in every cell of their body. Until now, it has been largely unknown if 1) these integrations are ancient, 2) if they still occur, and 3) whether circulating virus strains differ from integrated ones. Here, we used next-generation sequencing and mining of public human genome data sets to generate the largest and most diverse collection of circulating and integrated HHV-6 genomes studied to date. In genomes of geographically dispersed, only distantly related people, we identified clades of integrated viruses that originated from a single ancestral event, confirming this with fluorescent in situ hybridization to directly observe the integration locus. In contrast to HHV-6B, circulating and integrated HHV-6A sequences form distinct clades, arguing against ongoing integration of circulating HHV-6A or “reactivation” of integrated HHV-6A. Taken together, our study provides the first comprehensive picture of the evolution of HHV-6, and reveals that integration of heritable HHV-6 has occurred since the time of, if not before, human migrations out of Africa.
DRAM for distilling microbial metabolism to automate the curation of microbiome function
Authors: Shaffer Michael , Borton Mikayla A , McGivern Bridget B , Zayed Ahmed A , La Rosa Sabina Leanti , Solden Lindsey M , Liu Pengfei , Narrowe Adrienne B , Rodríguez-Ramos Josué , Bolduc Benjamin , Gazitúa M Consuelo , Daly Rebecca A , Smith Garrett J , Vik Dean R , Pope Phil B , Sullivan Matthew B , Roux Simon , Wrighton Kelly C 
Published: July 2020

AbstractMicrobial and viral communities transform the chemistry of Earth's ecosystems, yet the specific reactions catalyzed by these biological engines are hard to decode due to the absence of a scalable, metabolically resolved, annotation software. Here, we present DRAM (Distilled and Refined Annotation of Metabolism), a framework to translate the deluge of microbiome-based genomic information into a catalog of microbial traits. To demonstrate the applicability of DRAM across metabolically diverse genomes, we evaluated DRAM performance on a defined, in silico soil community and previously published human gut metagenomes. We show that DRAM accurately assigned microbial contributions to geochemical cycles and automated the partitioning of gut microbial carbohydrate metabolism at substrate levels. DRAM-v, the viral mode of DRAM, established rules to identify virally-encoded auxiliary metabolic genes (AMGs), resulting in the metabolic categorization of thousands of putative AMGs from soils and guts. Together DRAM and DRAM-v provide critical metabolic profiling capabilities that decipher mechanisms underpinning microbiome function.
Landscape of DNA binding signatures of myocyte enhancer factor-2B reveals a unique interplay of base and shape readout
Authors: Dantas Machado Ana Carolina , Cooper Brendon H , Lei Xiao , Di Felice Rosa , Chen Lin , Rohs Remo 
Published: July 2020

Abstract
Myocyte enhancer factor-2B (MEF2B) has the unique capability of binding to its DNA target sites with a degenerate motif, while still functioning as a gene-specific transcriptional regulator. Identifying its DNA targets is crucial given regulatory roles exerted by members of the MEF2 family and MEF2B’s involvement in B-cell lymphoma. Analyzing structural data and SELEX-seq experimental results, we deduced the DNA sequence and shape determinants of MEF2B target sites on a high-throughput basis in vitro for wild-type and mutant proteins. Quantitative modeling of MEF2B binding affinities and computational simulations exposed the DNA readout mechanisms of MEF2B. The resulting binding signature of MEF2B revealed distinct intricacies of DNA recognition compared to other transcription factors. MEF2B uses base readout at its half-sites combined with shape readout at the center of its degenerate motif, where A-tract polarity dictates nuances of binding. The predominant role of shape readout at the center of the core motif, with most contacts formed in the minor groove, differs from previously observed protein–DNA readout modes. MEF2B, therefore, represents a unique protein for studies of the role of DNA shape in achieving binding specificity. MEF2B–DNA recognition mechanisms are likely representative for other members of the MEF2 family.
Bleeding risk of haemodialysis and peritoneal dialysis patients
Authors: van Eck van der Sluijs Anita , Abrahams Alferso C , Rookmaaker Maarten B , Verhaar Marianne C , Bos Willem Jan W , Blankestijn Peter J , Dekker Friedo W , van Diepen Merel , Ocak Gurbey 
Published: July 2020

Abstract

Background
Dialysis patients have an increased bleeding risk as compared with the general population. However, there is limited information whether bleeding risks are different for patients treated with haemodialysis (HD) or peritoneal dialysis (PD). From a clinical point of view, this information could influence therapy choice. Therefore the aim of this study was to investigate the association between dialysis modality and bleeding risk.

Methods
Incident dialysis patients from the Netherlands Cooperative Study on the Adequacy of Dialysis were prospectively followed for major bleeding events over 3 years. Hazard ratios with 95% confidence intervals (CIs) were calculated for HD compared with PD using a time-dependent Cox regression analysis, with updates on dialysis modality.

Results
In total, 1745 patients started dialysis, of whom 1211 (69.4%) received HD and 534 (30.6%) PD. The bleeding rate was 60.8/1000 person-years for HD patients and 34.6/1000 person-years for PD patients. The time-dependent Cox regression analysis showed that after adjustment for age, sex, primary kidney disease, prior bleeding, cardiovascular disease, antiplatelet drug use, vitamin K antagonist use, erythropoietin use, arterial hypertension, residual glomerular filtratin rate, haemoglobin and albumin levels, bleeding risk for HD patients compared with PD increased 1.5-fold (95% CI 1.0–2.2).

Conclusions
In this large prospective cohort of incident dialysis patients, HD patients had an increased bleeding risk compared with PD patients. In particular, HD patients with a history of prior bleeding had an increased bleeding risk.
The Glioma-Network Interface: A Review of the Relationship Between Glioma Molecular Subtype and Intratumoral Function
Authors: Young Jacob S , Morshed Ramin A , Gogos Andrew J , Amara Dominic , Villanueva-Meyer Javier E , Berger Mitchel S , Hervey-Jumper Shawn L 
Published: July 2020

Abstract
Gliomas are a major cause of morbidity. Direct cortical stimulation mapping offers the ability to identify functional areas within the broader neural network both cortically and subcortically. Since the World Health Organization (WHO) 2016 classification categorized gliomas into molecular subgroups with varied molecular signatures and clinical behavior, it is possible that gliomas may demonstrate rates of functional network integration. We therefore retrospectively reviewed a data registry of 181 patients with dominant hemisphere frontal, parietal, insular, or temporal gliomas. Our goal was to test the hypothesis that WHO glioma histopathology and molecular subtype influences functional language or motor sites identified within the tumor. Intratumoral function as determined by direct cortical and subcortical stimulation mapping was identified at the highest rate in isocitrate dehydrogenase mutant astrocytomas and oligodendrogliomas. Finally, we reviewed the emerging literature exploring the interface between functional neural networks and gliomas. These data shed light on glioma molecular and histological characteristics most commonly associated within intratumoral function.
Tobacco Product Promotions Remain Ubiquitous and Are Associated with Use and Susceptibility to Use Among Adolescents
Authors: Fielding-Singh Priya , Epperson Anna E , Prochaska Judith J 
Published: July 2020

Abstract

Introduction
The decline in tobacco smoking among US adolescents has been exceeded by the exponential rise in nicotine vaping with an overall net gain in youth tobacco product use. While cigarette companies are restricted from advertising on television/radio, vaping promotions have been largely unrestricted. This study examined exposure to tobacco product promotions in a US sample of 1003 adolescents and its associations with product use and susceptibility to use.

Aims and Methods
Adolescents (13–17) were recruited online and anonymously surveyed in 2019 about their ever and current (past 30 days) tobacco smoking (cigarette and cigar) and nicotine vaping behaviors, and among never-users, susceptibility to vaping. Multivariate models tested associations with past-month exposure to tobacco product promotions controlling for demographic features, harm perceptions, and family and peer influences.

Results
Tobacco product use was 34% ever-use and 20% current-use. Most had seen cigarette (91%) and nicotine vaping (80%) product promotions in the past 30 days. A majority reported exposure at point-of-sale and on major (television and cinema) and social media. In adjusted multivariate models, greater exposure to tobacco product promotions was significantly associated with ever and current smoking and vaping; and among never-users, susceptibility to vaping (all p &lt; .01, effect sizes 1.03–1.05). Family/peer use and attitudes also were significant correlates.

Conclusions
Tobacco product promotions remain ubiquitous and are significantly associated with adolescents’ tobacco product use and susceptibility to vape. Peers and family are important social influences and may reflect indirect channels of tobacco marketing. Stricter regulatory restrictions on tobacco marketing to young people are warranted.

Implications
This study adds to mounting evidence showing that tobacco marketing remains pervasive and is associated with tobacco use and susceptibility to use. Most youth report seeing cigarette and nicotine vaping product promotions, with notable differences by channel: traditional media predominate for cigarettes and social media/email for e-cigarettes. Greater exposure to tobacco promotions is significantly associated with ever and current smoking and vaping, and among never-users, susceptibility to vaping. The accumulating findings support stricter regulatory restrictions on marketing of tobacco products in media channels accessed by youth.
Zoned Crystal Records of Transcrustal Magma Transport, Storage and Differentiation: Insights from the Shatsky Rise Oceanic Plateau
Authors: van Gerve T D , Neave D A , Almeev R R , Holtz F , Namur O 
Published: July 2020

AbstractMagmatic processes occurring in the deepest parts of sub-volcanic plumbing systems remain poorly constrained. However, crystal mush fragments incorporated into ascending magmas can provide valuable insights into the processes and conditions of transcrustal magma transport, storage and differentiation. Here we use lava samples drilled from Tamu Massif, Shatsky Rise, to understand the magmatic processes taking place in a region of thickened oceanic crust. We observe correlations between crystal textures and compositional zones in plagioclase that reveal relationships between mechanisms of magmatic differentiation and the crustal depths at which they occurred. When combined with geothermobarometric models, our observations indicate that deep crustal crystal storage took place in high-crystallinity mushes at two discrete levels (∼17 and ∼27 km depth). Diffusive constraints from crystal zoning lengthscales indicate that the lifetime of crystals within the mushes exceeded several thousand years. Magmatic recharge was frequent and produced various dissolution textures in plagioclase. In contrast, shallow crystal storage (∼2·4 km depth) took place in a liquid-dominated domain where crystal residence times were much shorter. Crystal zoning patterns indicate that magmas transporting crystals from the deepest environment to the surface sometimes accumulated additional crystals from mid-crustal storage regions and sometimes did not, highlighting the complexity of magma assembly processes. Temperature contrasts in the lower crust at Shatsky Rise are probably low, owing to extensive magma input and a paucity of hydrothermal cooling at depth. Crystal growth morphologies are consequently relatively simple. Crystallization in thick and thermally mature crusts may therefore lead to less complexity in crystal textures than crystallization in thinner crusts where temperature contrasts are higher. Our observations indicate that combining thermobarometry with studies of crystal textures and crystal compositions is a powerful approach for improving our understanding of magmatic differentiation and magma ascent paths.
A matter of time and proportion: the availability of phosphorus-rich phytoplankton influences growth and behavior of copepod nauplii
Authors: Meunier Cédric L , Herstoff Emily M , Geisen Carla , Boersma Maarten 
Published: July 2020

Abstract
Although consumers may use selective feeding to cope with suboptimal resource quality, little work has examined the mechanisms that underlie selective feeding, the efficiency of this behavior or its influence on consumer growth rate. Furthermore, a consumer’s exposure to suboptimal resources may also influence the consumer’s behavior and life history, including growth rate. Here, we studied how the availability of P-rich and P-poor phytoplankton influences the growth and behavior of copepod nauplii. We observed that copepod nauplii preferentially feed on P-rich prey. We also found that even relatively short exposure to P-rich phytoplankton yielded higher nauplii growth rates, whereas the presence of P-poor phytoplankton in a mixture impaired growth. Overall, we observed that swimming speed decreased with increasing phytoplankton P-content, which is a behavioral adjustment that may improve utilization of heterogeneously distributed high-quality food in the field. Based on our results, we propose that the optimal prey C: P ratio for copepod nauplii is very narrow, and that deviations from this optimum have severe negative consequences for growth.