bluuebunny/crossref_metadata_2025_split huggingface dataset:
Emerge: Empirical predictions of galaxy merger rates since z ∼ 6
Authors: O’Leary Joseph A , Moster Benjamin P , Naab Thorsten , Somerville Rachel S 
Published: December 2020

Abstract
We explore the galaxy-galaxy merger rate with the empirical model for galaxy formation, emerge. On average, we find that between 2 per cent and 20 per cent of massive galaxies (log10(m*/M⊙) ≥ 10.3) will experience a major merger per Gyr. Our model predicts galaxy merger rates that do not scale as a power-law with redshift when selected by descendant stellar mass, and exhibit a clear stellar mass and mass-ratio dependence. Specifically, major mergers are more frequent at high masses and at low redshift. We show mergers are significant for the stellar mass growth of galaxies log10(m*/M⊙) ≳ 11.0. For the most massive galaxies major mergers dominate the accreted mass fraction, contributing as much as 90 per cent of the total accreted stellar mass. We reinforce that these phenomena are a direct result of the stellar-to-halo mass relation, which results in massive galaxies having a higher likelihood of experiencing major mergers than low mass galaxies. Our model produces a galaxy pair fraction consistent with recent observations, exhibiting a form best described by a power-law exponential function. Translating these pair fractions into merger rates results in an inaccurate prediction compared to the model intrinsic values when using published observation timescales. We find the pair fraction can be well mapped to the intrinsic merger rate by adopting an observation timescale that decreases linearly with redshift as Tobs = −0.36(1 + z) + 2.39 [Gyr], assuming all observed pairs merge by z = 0.
Galaxy mass profiles from strong lensing III: The two-dimensional broken power-law model
Authors: O’Riordan C M , Warren S J , Mortlock D J 
Published: December 2020

Abstract
When modelling strong gravitational lenses, i.e., where there are multiple images of the same source, the most widely used parameterisation for the mass profile in the lens galaxy is the singular power-law model ρ(r)∝r−γ. This model may be insufficiently flexible for very accurate work, for example measuring the Hubble constant based on time delays between multiple images. Here we derive the lensing properties – deflection angle, shear, and magnification – of a more adaptable model where the projected mass surface density is parameterised as a continuous two-dimensional broken power-law (2DBPL). This elliptical 2DBPL model is characterised by power-law slopes t1, t2 either side of the break radius θB. The key to the 2DBPL model is the derivation of the lensing properties of the truncated power law (TPL) model, where the surface density is a power law out to the truncation radius θT and zero beyond. This TPL model is also useful by itself. We create mock observations of lensing by a TPL profile where the images form outside the truncation radius, so there is no mass in the annulus covered by the images. We then show that the slope of the profile interior to the images may be accurately recovered for lenses of moderate ellipticity. This demonstrates that the widely-held notion that lensing measures the slope of the mass profile in the annulus of the images, and is insensitive to the mass distribution at radii interior to the images, is incorrect.
Analysis of the IBEX-Lo interstellar hydrogen fluxes collected in 2009–2018 as a tool for sensing of the solar radiation pressure and the hydrogen ionization rate
Authors: Katushkina O A , Galli A , Izmodenov V V , Alexashov D B 
Published: December 2020

ABSTRACT
The Interstellar Boundary Explorer (IBEX) has been measuring interstellar hydrogen fluxes at 1 au since 2009. In this paper, we analysed all available data obtained with the IBEX-Lo instrument at energies 11–41 eV using our numerical kinetic model of the interstellar hydrogen distribution in the heliosphere. We performed a fitting of the data to find independently the model parameters: the ratio of the solar radiation pressure to the solar gravitation (μ0), ionization rate of hydrogen atoms at 1 au (β0), parameters of the secondary interstellar atoms at 70 au from the Sun, which provide the best agreement with the data by minimization of metric χ2. We also analysed temporal variations of the ratio of the fluxes measured in a fixed direction at energy bin 1 and energy bin 2. It is found that in 2009–2011 and 2017–2016 the ratio provided by the model is smaller than in the IBEX-Lo data, while in 2012–2015, oppositely, the model ratio is larger compared to the data. This might be caused by the incorrect separation of the measured fluxes between energy channels in the data, or by some additional physical factors that are omitted in the model. Understanding this issue may be important for the preparation of future Interstellar Mapping and Acceleration Probe mission. At this stage, we relied on the sum of the fluxes measured in energy bins 1 and 2 for comparison to model predictions.
SDSS-IV MaNGA: galaxy gas-phase metallicity gradients vary across the mass–size plane
Authors: Boardman N F , Zasowski G , Newman J A , Sanchez S F , Schaefer A , Lian J , Bizyaev D , Drory N 
Published: December 2020

ABSTRACT
Gas-phase abundances and abundance gradients provide much information on past stellar generations, and are powerful probes of how galaxies evolve. Gas abundance gradients in galaxies have been studied as functions of galaxies’ mass and size individually, but have largely not been considered across the galaxy mass–size plane. Thus, we investigate gas-phase abundance gradients across this plane, using a sample of over 1000 galaxies selected from the MApping Nearby Galaxies at APO (MaNGA) spectroscopic survey. We find that gradients vary systematically such that above 1010 M⊙, smaller galaxies display flatter gradients than larger galaxies at a given stellar mass. This mass–size behaviour cannot be explained by instrumental effects, nor is it simply a reflection of known trends between gradients and morphology. We explore multiple possibilities for a physical origin for this pattern, though further work is needed to establish a firm physical interpretation.
Measuring the distance to the black hole candidate X-ray binary MAXI J1348–630 using H i absorption
Authors: Chauhan J , Miller-Jones J C A , Raja W , Allison J R , Jacob P F L , Anderson G E , Carotenuto F , Corbel S , Fender R , Hotan A , Whiting M , Woudt P A , Koribalski B , Mahony E 
Published: December 2020

ABSTRACT
We present neutral hydrogen (H i) absorption spectra of the black hole candidate X-ray binary (XRB) MAXI J1348–630 using the Australian Square Kilometre Array Pathfinder (ASKAP) and MeerKAT. The ASKAP H i spectrum shows a maximum negative radial velocity (with respect to the local standard of rest) of −31 ± 4 km s−1 for MAXI J1348–630, as compared to −50 ± 4 km s−1 for a stacked spectrum of several nearby extragalactic sources. This implies a most probable distance of $2.2^{+0.5}_{-0.6}$ kpc for MAXI J1348–630, and a strong upper limit of the tangent point distance at 5.3 ± 0.1 kpc. Our preferred distance implies that MAXI J1348–630 reached 17 ± 10  per cent of the Eddington luminosity at the peak of its outburst, and that the source transited from the soft to the hard X-ray spectral state at 2.5 ± 1.5  per cent of the Eddington luminosity. The MeerKAT H i spectrum of MAXI J1348–630 (obtained from the older, low-resolution 4k mode) is consistent with the re-binned ASKAP spectrum, highlighting the potential of the eventual capabilities of MeerKAT for XRB spectral line studies.
Dynamics of TRF1 organizing a single human telomere
Authors: Li Xu , Wang Meijie , Zheng Wei , Huang Wei , Wang Zeyu , Jin Kairang , Liu Lin , Yu Zhongbo 
Published: December 2020

Abstract
Chromosome stability is primarily determined by telomere length. TRF1 is the core subunit of shelterin that plays a critical role in telomere organization and replication. However, the dynamics of TRF1 in scenarios of telomere-processing activities remain elusive. Using single-molecule magnetic tweezers, we here investigated the dynamics of TRF1 upon organizing a human telomere and the protein-DNA interactions at a moving telomeric fork. We first developed a method to obtain telomeres from human cells for directly measuring the telomere length by single-molecule force spectroscopy. Next, we examined the compaction and decompaction of a telomere by TRF1 dimers. TRF1 dissociates from a compacted telomere with heterogenous loops in ∼20 s. We also found a negative correlation between the number of telomeric loops and loop sizes. We further characterized the dynamics of TRF1 at a telomeric DNA fork. With binding energies of 11 kBT, TRF1 can modulate the forward and backward steps of DNA fork movements by 2–9 s at a critical force of F1/2, temporarily maintaining the telomeric fork open. Our results shed light on the mechanisms of how TRF1 organizes human telomeres and facilitates the efficient replication of telomeric DNA. Our work will help future research on the chemical biology of telomeres and shelterin-targeted drug discovery.
Nasal Methicillin-Resistant Staphylococcus aureus Carriage Among Foreign Workers Recruited to Taiwan From Southeastern Asian Countries
Authors: Chen Kuan-Hung , Chuang Wen-Ching , Wong Wang-Kin , Chuang Chih-Hsien , Chen Chih-Jung , Huang Yhu-Chering 
Published: December 2020

Abstract

Background
In 2012, we identified the dissemination of methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST)45 strain in 14 nursing homes in Taiwan and foreign nurse workers, a significant risk factor for MRSA carriage. We conducted this study to understand MRSA carriage and molecular characteristics among foreign workers recruited from Southeastern Asian countries.

Methods
A cross-sectional study involving a total of 1935 foreign workers—929 (arrival group) and 1006 (staying group)—from Vietnam (n = 843), Indonesia (n = 780), the Philippines (n = 239), and Thailand (n = 70) were conveniently recruited during upon-arrival and regular health examination in a regional hospital. A nasal swab was obtained from each participant for detection of MRSA.

Results
Overall, MRSA carriage rate was 2.72%, with 2.26% for arrival group and 3.18% for staying group, and 4.74% for Vietnamese, 1.28% for Indonesians, 1.26% for Filipino, and none for Thai workers. Pulsotype AK/ST45 (57%) and pulsotype AX/ST188 (14%) were the top 2 dominant clones for the arrival group, whereas pulsotype D/ST59 (41%) (an endemic community clone in Taiwan) and pulsotype AK/ST45 (19%) were predominant for the staying group. A significant decrease of pulsotype AK/ST45 from 57% to 19% (P = .007) and increase of pulsotype D/ST59 from 4.8% to 41% (P = .004) were found between the arrival and the staying groups.

Conclusions
Approximately 3% of foreign workers recruited from Southeastern Asian countries to Taiwan were colonized with MRSA, including the ST45 strain. However, the MRSA isolates from workers staying in Taiwan were mostly a locally endemic clone and genetically different from those identified from workers on arrival.
Thymosin Alpha 1 Mitigates Cytokine Storm in Blood Cells From Coronavirus Disease 2019 Patients
Authors: Matteucci Claudia , Minutolo Antonella , Balestrieri Emanuela , Petrone Vita , Fanelli Marialaura , Malagnino Vincenzo , Ianetta Marco , Giovinazzo Alessandro , Barreca Filippo , Di Cesare Silvia , De Marco Patrizia , Miele Martino Tony , Toschi Nicola , Mastino Antonio , Sinibaldi Vallebona Paola , Bernardini Sergio , Rogliani Paola , Sarmati Loredana , Andreoni Massimo , Grelli Sandro , Garaci Enrico 
Published: December 2020

Abstract

Background
Coronavirus disease 2019 (COVID-19) is characterized by immune-mediated lung injury and complex alterations of the immune system, such as lymphopenia and cytokine storm, that have been associated with adverse outcomes underlining a fundamental role of host response in severe acute respiratory syndrome coronavirus 2 infection and the pathogenesis of the disease. Thymosin alpha 1 (Tα1) is one of the molecules used in the management of COVID-19, because it is known to restore the homeostasis of the immune system during infections and cancer.

Methods
In this study, we captured the interconnected biological processes regulated by Tα1 in CD8+ T cells under inflammatory conditions.

Results
Genes associated with cytokine signaling and production were upregulated in blood cells from patients with COVID-19, and the ex vivo treatment with Tα1-mitigated cytokine expression, and inhibited lymphocyte activation in a CD8+ T-cell subset specifically.

Conclusion
These data suggest the potential role of Tα1 in modulating the immune response homeostasis and the cytokine storm in vivo.
Interactions between a planktivorous fish and planktonic microcrustaceans mediated by the biomass of aquatic macrophytes
Authors: Quirino Bárbara Angélio , Teixeira de Mello Franco , Deosti Sabrina , Bonecker Claudia Costa , Cardozo Ana Lúcia Paz , Yofukuji Katia Yasuko , Aleixo Matheus Henrique Ferreira , Fugi Rosemara 
Published: December 2020

AbstractHabitat complexity is recognized to mediate predator–prey relationships by offering refuge or not. We investigated the availability of planktonic microcrustaceans and the diet of a planktivorous fish (Hyphessobrycon eques) at different levels (low, intermediate and high) of aquatic macrophyte biomass. Sampling was carried out in a river with low flow speed, located in a Neotropical floodplain. We collected fish and microcrustaceans in macrophyte stands with variations in biomass. There were no differences in microcrustacean density in the water among the levels of macrophyte biomass, but microcrustacean richness and diet composition of H. eques differed. Microcrustacean richness and trophic niche breadth of the planktivorous fish were higher in high biomass stands. There was high consumption of a small cladoceran species in low macrophyte biomass, which was replaced by larger species, such as copepods, in intermediate and high biomass. Thus, the selection of some species was different among the biomass levels. These results suggest that plant biomass plays an important role in the interaction between fish and microcrustaceans, and prey characteristics such as size, escape ability and energy value make them more or less subject to predation by fish according to habitat structuring.
Hydrozoans, scyphozoans, larvaceans and ctenophores observed in situ at hadal depths
Authors: Jamieson Alan J , Linley Thomas D 
Published: December 2020

Abstract
Hydrozoa, Scyphozoa, Larvacea (Appendicularia) and Ctenophora are not typically associated with hadal communities. Here, we report observations of these groups based on 136 benthic camera lander deployments that spanned all five oceans, encompassing 14 deep sites, culminating in &gt;1000 h of video in the near-bottom waters between 5000 and 10 925 m. Of the Hydrozoa, trachymedusae had a maximum depth of 9066 m in the Mariana Trench, narcomedusae were recorded to a maximum depth of 7220 m in the San Cristobal Trench and a single siphonophore was seen at 7888 m in the Mariana Trench. Scyphozoans were seen as deep as 6898 m in the New Hebrides Trench. The deepest ctenophore was seen at 6037 m in the Kermadec Trench. Larvaceans were seen in the Agulhas Fracture Zone and the Puerto Rico, Kermadec, South Shetland and Java trenches, with the deepest being 7176 m in the Java Trench. None of these groups were seen in the deep Arctic or Antarctic deeper than 6000 m. Narcomedusae, siphonophorae, Scyphozoa and Ctenophora appear very rare at hadal depths, while the larvaceans and trachymedusae appear to be relatively conspicuous in the benthopelagic at hadal depths.
Against the Doctrine of Infallibility
Authors: Willard-Kyle Christopher 
Published: December 2020

AbstractAccording to the doctrine of infallibility, one is permitted to believe p if one knows that necessarily, one would be right if one believed that p. This plausible principle—made famous in Descartes’ cogito—is false. There are some self-fulfilling, higher-order propositions one can’t be wrong about but shouldn’t believe anyway: believing them would immediately make one's overall doxastic state worse.
Supply Chain Disruptions: Evidence from the Great East Japan Earthquake*
Authors: Carvalho Vasco M , Nirei Makoto , Saito Yukiko U , Tahbaz-Salehi Alireza 
Published: December 2020

AbstractExploiting the exogenous and regional nature of the Great East Japan Earthquake of 2011, this article provides a quantification of the role of input-output linkages as a mechanism for the propagation and amplification of shocks. We document that the disruption caused by the disaster propagated upstream and downstream along supply chains, affecting the direct and indirect suppliers and customers of disaster-stricken firms. Using a general equilibrium model of production networks, we then obtain an estimate for the overall macroeconomic impact of the disaster by taking these propagation effects into account. We find that the earthquake and its aftermaths resulted in a 0.47 percentage point decline in Japan’s real GDP growth in the year following the disaster.
Real-world single centre use of JAK inhibitors across the rheumatoid arthritis pathway
Authors: Fitton John , Melville Andrew R , Emery Paul , Nam Jacqueline L , Buch Maya H 
Published: December 2020

Abstract

Objectives
To evaluate real-world efficacy of approved JAK inhibitors (JAKi) tofacitinib and baricitinib in a large, single-centre cohort of RA patients across the treatment pathway, including those refractory to multiple biologic drugs.

Methods
All RA patients, treated with tofacitinib (from time of compassionate access scheme) or baricitinib since approval in 2017 had DAS28-CRP scores and components recorded at baseline, 3 and 6 months (with retrospective data for compassionate access scheme). Efficacy was evaluated in the total cohort, each treatment group, and subgroups of number of prior biologic classes failed.

Results
One hundred and fifteen patients were treated with a JAKi (tofacitinib 54, baricitinib 69, 8 both); 76.4% female; mean (s.d.) age 57.3 (14.3) years. On average patients had received three previous bDMARDs; 11 (9.6%) were bDMARD naïve. Combined group baseline DAS28-CRP (s.d.) 5.62(1.14) improved by 1.49(1.44) and 1.67(1.61) at 3 and 6 months, respectively, comparable in individual JAKi groups; with 24% in at least low disease activity at 3 months. The biggest improvement was observed in the biologic-naïve group (mean DAS28-CRP improved from 5.16–2.14 after 6 months); while those with prior exposure to minimum three bDMARD classes had DAS28-CRP improvement of &gt;1.2. Five out of 8 patients treated with both JAKi sequentially responded. Twelve patients previously unresponsive to IL-6 blockade responded to JAKi. No unexpected safety events were recorded. Two cases of venous thromboembolism were observed.

Conclusion
JAK inhibition is effective in a real-world population of RA patients, including in a subset of patients refractory to multiple previous bDMARDs.
Class Inequality in Parental Childcare Time: Evidence from Synthetic Couples in the ATUS
Authors: LaBriola Joe , Schneider Daniel 
Published: December 2020

Abstract
The time that parents spend teaching and playing with their young children has important consequences for later life achievement and attainment. Previous research suggests that there are significant class inequalities in how much time parents devote to this kind of developmental childcare in the United States. Yet, due in part to data limitations, prior research has not accounted for how class inequalities in family structure, assortative mating, and specialization between partners may exacerbate or ameliorate these gaps. We match parental respondents within the American Time Use Survey (ATUS) to generate synthetic parental dyads, which we use to estimate, in turn, the contributions of family structure, assortative mating, and specialization to class gaps in parental time spent in developmental care of children aged 0–6. We find some evidence that accounting for class differences in family structure widens income gaps in total parental time in developmental childcare of young children. Further, we show that assortative mating of parents widens educational gaps in developmental childcare, whereas specialization between partners marginally widens these class divides. Although the net effect of these three processes on income-based gaps in childcare time is modest, accounting for these three processes more than doubles education-based gaps in total parental developmental childcare as compared to maternal time alone. Our findings from this novel empirical approach provide a more holistic view of the extent and sources of inequality in parental time investments in young children’s cognitive and social development.
Headship and Poverty in Africa
Authors: Brown Caitlin , van de Walle Dominique 
Published: December 2020

AbstractStandard welfare comparisons between female-headed households (FHHs) and male-headed households (MHHs) have largely ignored two confounding factors: marital status (affecting access to assets and markets) and heterogeneity in household demographics (with bearing on economies of scale in consumption). Both influence welfare and are correlated with sex of headship. As judged by the usual per capita welfare measures, FHHs have lower poverty rates than MHHs in Africa. However, even a modest adjustment for economies of scale in consumption changes the poverty comparisons, with FHHs faring significantly worse overall in East, Central, and Southern Africa. Marital status also matters: the households of female heads are poorer than MHHs except when the female head is married. Taking the head's marital status and the household's demographics into account is critical to the association between female headship and welfare outcomes.
Trade Union Responses to Ageing Workplaces: Lessons from the UK
Authors: Ball Chris , Flynn Matt 
Published: December 2020

AbstractIn 2017, European-level unions and business associations agreed a framework for national and workplace level employers and union representatives to take collaborative action to design workforce responses to demographic ageing. This article discusses how unions are responding to pressures to extend working life in the UK. Drawing on industrial relations and social movement literature, it argues that unions pursue the twin strategies of working in partnership with like-minded employers to reorient workplaces towards an age friendly model while organizing and campaigning with members to secure conditions consistent with active and healthy ageing. Resisting an erosion of pension and retirement rights and extending employment protection are examples of this approach, but numerous lower profile initiatives by workplace representatives are also reflective of their having an age friendly agenda. Using qualitative data from focus group discussions with union representatives in two sectors, the article shows that union responses are rooted in both of the dominant models of British unionism—the organizing and partnership models—and argues that literature on social movements helps to understand how union representatives reconcile the competing pressures.