bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of Core-collapse Supernovae in Explaining Solar System Abundances of p Nuclides
Authors: Travaglio C. , Rauscher T. , Heger A. , Pignatari M. , West C. 
Published: February 2018

Abstract
The production of the heavy stable proton-rich isotopes between 74Se and 196Hg—the p nuclides—is due to the contribution from different nucleosynthesis processes, activated in different types of stars. Whereas these processes have been subject to various studies, their relative contributions to Galactic chemical evolution (GCE) are still a matter of debate. Here we investigate for the first time the nucleosynthesis of p nuclides in GCE by including metallicity and progenitor mass-dependent yields of core-collapse supernovae (ccSNe) into a chemical evolution model. We used a grid of metallicities and progenitor masses from two different sets of stellar yields and followed the contribution of ccSNe to the Galactic abundances as a function of time. In combination with previous studies on p-nucleus production in thermonuclear supernovae (SNIa), and using the same GCE description, this allows us to compare the respective roles of SNeIa and ccSNe in the production of p-nuclei in the Galaxy. The γ process in ccSN is very efficient for a wide range of progenitor masses (13 M
⊙–25 M
⊙) at solar metallicity. Since it is a secondary process with its efficiency depending on the initial abundance of heavy elements, its contribution is strongly reduced below solar metallicity. This makes it challenging to explain the inventory of the p nuclides in the solar system by the contribution from ccSNe alone. In particular, we find that ccSNe contribute less than 10% of the solar p nuclide abundances, with only a few exceptions. Due to the uncertain contribution from other nucleosynthesis sites in ccSNe, such as neutrino winds or α-rich freeze out, we conclude that the light p-nuclides 74Se, 78Kr, 84Sr, and 92Mo may either still be completely or only partially produced in ccSNe. The γ-process accounts for up to twice the relative solar abundances for 74Se in one set of stellar models and 196Hg in the other set. The solar abundance of the heaviest p nucleus 196Hg is reproduced within uncertainties in one set of our models due to photodisintegration of the Pb isotopes 208,207,206Pb. For all other p nuclides, abundances as low as 2% of the solar level were obtained.
Imaging and Variability Studies of CTA 102 during the 2016 January γ-ray Flare
Authors: Li Xiaofeng , Mohan P. , An T. , Hong Xiaoyu , Cheng Xiaopeng , Yang Jun , Zhang Yingkang , Zhang Zhongli , Zhao Wei 
Published: February 2018

Abstract
The γ-ray-bright blazar CTA 102 is studied using imaging (new 15 GHz and archival 43 GHz Very Long Baseline Array, VLBA data) and time variable optical flux density, polarization degree, and electric vector position angle (EVPA) spanning between 2015 June 1 and 2016 October 1, covering a prominent γ-ray flare during 2016 January. The pc-scale jet indicates expansion with oscillatory features up to 17 mas. Component proper motions are in the range 0.04–0.33 mas yr−1 with acceleration up to 1.2 mas followed by a slowing down beyond 1.5 mas. A jet bulk Lorentz factor ≥17.5, position angle of 128.°3, inclination angle ≤6.°6 and intrinsic half opening angle ≤1.°8 are derived from the VLBA data. These inferences are employed in a helical jet model to infer long-term variability in flux density, polarization degree, EVPA, and a rotation of the Stokes Q and U parameters. A core distance of r
core,43 GHz = 22.9 pc, and a magnetic field strength at 1 pc and the core location of 1.57 G and 0.07 G, respectively, are inferred using the core-shift method. The study is useful in the context of estimating jet parameters and in offering clues to distinguish mechanisms responsible for variability over different timescales.
Dynamical Formation of Close Binaries during the Pre-main-sequence Phase
Authors: Moe Maxwell , Kratter Kaitlin M. 
Published: February 2018

Abstract
Solar-type binaries with short orbital periods (

days; a ≲ 0.1 au) cannot form directly via fragmentation of molecular clouds or protostellar disks, yet their component masses are highly correlated, suggesting interaction during the pre-main-sequence (pre-MS) phase. Moreover, the close binary fraction of pre-MS stars is consistent with that of their MS counterparts in the field (

). Thus, we can infer that some migration mechanism operates during the early pre-MS phase (τ ≲ 5 Myr) that reshapes the primordial separation distribution. We test the feasibility of this hypothesis by carrying out a population synthesis calculation which accounts for two formation channels: Kozai–Lidov (KL) oscillations and dynamical instability in triple systems. Our models incorporate (1) more realistic initial conditions compared to previous studies, (2) octupole-level effects in the secular evolution, (3) tidal energy dissipation via weak-friction equilibrium tides at small eccentricities and via non-radial dynamical oscillations at large eccentricities, and (4) the larger tidal radius of a pre-MS primary. Given a 15% triple-star fraction, we simulate a close binary fraction from KL oscillations alone of

after τ = 5 Myr, which increases to

by τ = 5 Gyr. Dynamical ejections and disruptions of unstable coplanar triples in the disk produce solitary binaries with slightly longer periods P ≈ 10–100 days. The remaining ≈60% of close binaries with outer tertiaries, particularly those in compact coplanar configurations with log

(days) ≈ 2–5 (

au), can be explained only with substantial extra energy dissipation due to interactions with primordial gas.
Hidden Universality in the Merger Rate Distribution in the Primordial Black Hole Scenario
Authors: Kocsis Bence , Suyama Teruaki , Tanaka Takahiro , Yokoyama Shuichiro 
Published: February 2018

Abstract
It has been proposed that primordial black holes (PBHs) form binaries in the radiation dominated era. Once formed, some fraction of them may merge within the age of the universe by gravitational radiation reaction. We investigate the merger rate of the PBH binaries when the PBHs have a distribution of masses around

, which is a generalization of the previous studies where the PBHs are assumed to have the same mass. After deriving a formula for the merger time probability distribution in the PBH mass plane, we evaluate it under two different approximations. We identify a quantity constructed from the mass distribution of the merger rate density per unit cosmic time and comoving volume

,

, which universally satisfies 0.97 ≲ α ≲ 1.05 for all binary masses independently of the PBH mass function. This result suggests that the measurement of this quantity is useful for testing the PBH scenario.
Rapid Evolution of the Gaseous Exoplanetary Debris around the White Dwarf Star HE 1349–2305
Authors: Dennihy E. , Clemens J. C. , Dunlap B. H. , Fanale S. M. , Fuchs J. T. , Hermes J. J. 
Published: February 2018

Abstract
Observations of heavy metal pollution in white dwarf stars indicate that metal-rich planetesimals are frequently scattered into star-grazing orbits, tidally disrupted, and accreted onto the white dwarf surface, offering direct insight into the dynamical evolution of post-main-sequence exoplanetary systems. Emission lines from the gaseous debris in the accretion disks of some of these systems show variations on timescales of decades, and have been interpreted as the general relativistic precession of a recently formed, elliptical disk. Here we present a comprehensive spectroscopic monitoring campaign of the calcium infrared triplet emission in one system, HE 1349–2305, which shows morphological emission profile variations suggestive of a precessing, asymmetric intensity pattern. The emission profiles are shown to vary on a timescale of one to two years, which is an order of magnitude shorter than what has been observed in other similar systems. We demonstrate that this timescale is likely incompatible with general relativistic precession, and consider alternative explanations for the rapid evolution, including the propagation of density waves within the gaseous debris. We conclude with recommendations for follow-up observations, and discuss how the rapid evolution of the gaseous debris in HE 1349–2305 could be leveraged to test theories of exoplanetary debris disk evolution around white dwarf stars.
Stellar Bar Evolution in the Absence of Dark Matter Halo
Authors: Roshan Mahmood 
Published: February 2018

Abstract
We study the stellar bar growth in high-resolution numerical galaxy models with and without dark matter halos. In all models, the galactic disk is exponential, and the halos are rigid or live Plummer spheres. More specifically, when there is no dark matter halo, we modify the gravitational force between point particles. To do so, we use the weak field limit of an alternative theory of dark matter known as MOG in the literature. The galaxy model in MOG has the same initial conditions as galaxy models with a dark matter halo. On the other hand, the initial random velocities and Toomre’s local stability parameter are the same for all of the models. We show that the evolution and growth of the bar in MOG is substantially different from the standard cases including dark matter halo. More importantly, we find that the bar growth rate and its final magnitude are smaller in MOG. On the other hand, the maximum value of the bar in MOG is smaller than that in the Newtonian models. It is shown that although the live dark matter halo may support bar instability, MOG has stabilizing effects. Furthermore, we show that MOG supports fast pattern speeds, and unlike in the dark matter halo models, the pattern speed does not decrease with time. These differences, combined with the relevant observations, may help to distinguish between dark matter and modified gravity in galactic scales.
Quelles sont les difficultés essentielles de la zone euro ?
Authors: Artus Patrick 
Published: February 2018

Nous nous intéressons aux difficultés structurelles majeures de la zone euro et aux moyens de les corriger. Il s’agit de l’hétérogénéité croissante des économies des pays, due en particulier à la divergence des spécialisations productives, et de l’absence de correction de cette hétérogénéité par le fédéralisme ; de l’arrêt de la mobilité des capitaux entre les pays de l’OCDE ; de l’absence de coordination des politiques économiques qui génèrent des externalités entre les pays de la zone euro ; du caractère asymétrique des mécanismes d’ajustement (des politiques budgétaires, des compétitivités-coûts) qui ne sont mises en place que par les pays en difficulté ; de la gestion difficile de la politique budgétaire et de l’endettement public. Nous pensons que les difficultés de la zone euro peuvent être rangées dans trois catégories : l’absence de mécanisme qui permet de lutter contre les hétérogénéités ; l’absence de coordination des politiques économiques et la divergence dans les fonctionnements des marchés du travail ; les erreurs des politiques économiques dans leur conception et dans leur mise en œuvre.
Comment l’employeur peut-il soutenir la formation continue et le développement professionnel infirmier ? Résultats d’une étude qualitative canadienne auprès d’infirmières de soutien à domicile
Authors: Ouellet Jérôme , Mukamurera Joséphine 
Published: February 2018

Introduction : cet article s’intéresse au soutien de l’employeur en matière de formation continue (fc) des infirmières en soutien à domicile (sad). Contexte : les écrits font état d’un manque de financement de la part de l’employeur en matière de fc destinée aux infirmières. Toutefois, très peu d’études se sont intéressées à ce phénomène en sad. Objectif : l’étude visait à identifier les facteurs influençant l’engagement, la participation et le choix d’activités de fc d’infirmières de sad. Méthode : huit infirmières provenant d’un milieu de sad de l’Estrie (Québec, Canada) ont participé à des entrevues individuelles semi-dirigées. Les données ont fait l’objet d’une analyse thématique, d’une validation intra et inter-juge, puis d’un retour aux acteurs. Résultats : le soutien de l’employeur est un facteur important se déclinant en cinq aspects : financier, formatif, affectif, instrumental et normatif. Malgré le manque de financement et un accès limité à des activités, les infirmières de sad ont tout de même une perception plutôt positive du soutien de leur employeur en matière de fc. Discussion : néanmoins, l’employeur devrait accorder plus d’importance aux besoins exprimés par les infirmières de sad en les impliquant davantage dans les décisions qui les concernent en matière de fc.
Expression characterization and functional implication of the collagen-modifying Leprecan proteins in mouse gonadal tissue and mature sperm
Authors: Zimmerman Sarah M. , Besio Roberta , Heard-Lipsmeyer Melissa E. , Dimori Milena , Castagnola Patrizio , Swain Frances L. , Gaddy Dana , Diekman Alan B. , Morello Roy 
Published: February 2018

AbstractThe Leprecan protein family which includes the prolyl 3-hydroxylase enzymes (P3H1, P3H2, and P3H3), the closely related cartilage-associated protein (CRTAP), and SC65 (Synaptonemal complex 65, aka P3H4, LEPREL4), is involved in the post-translational modification of fibrillar collagens. Mutations in CRTAP, P3H1 and P3H2 cause human genetic diseases. We recently showed that SC65 forms a stable complex in the endoplasmic reticulum with P3H3 and lysyl hydroxylase 1 and that loss of this complex leads to defective collagen lysyl hydroxylation and causes low bone mass and skin fragility. Interestingly, SC65 was initially described as a synaptonemal complex-associated protein, suggesting a potential additional role in germline cells. In the present study, we describe the expression of SC65, CRTAP and other Leprecan proteins in postnatal mouse reproductive organs. We detect SC65 expression in peritubular cells of testis up to 4 weeks of age but not in cells within seminiferous tubules, while its expression is maintained in ovarian follicles until adulthood. Similar to bone and skin, SC65 and P3H3 are also tightly co-expressed in testis and ovary. Moreover, we show that CRTAP, a protein normally involved in collagen prolyl 3-hydroxylation, is highly expressed in follicles and stroma of the ovary and in testes interstitial cells at 4 weeks of age, germline cells and mature sperm. Importantly, CrtapKO mice have a mild but significant increase in morphologically abnormal mature sperm (17% increase compared to WT). These data suggest a role for the Leprecans in the post-translational modification of collagens expressed in the stroma of the reproductive organs. While we could not confirm that SC65 is part of the synaptonemal complex, the expression of CRTAP in the seminiferous tubules and in mature sperm suggest a role in the testis germ cell lineage and sperm morphogenesis.
Many Th Cell Subsets Have Fas Ligand–Dependent Cytotoxic Potential
Authors: Kotov Dmitri I. , Kotov Jessica A. , Goldberg Michael F. , Jenkins Marc K. 
Published: February 2018

Abstract
CD4+ Th cells can have cytotoxic activity against cells displaying relevant peptide-MHC class II (p:MHCII) ligands. Cytotoxicity may be a property of Th1 cells and depends on perforin and the Eomes transcription factor. We assessed these assertions for polyclonal p:MHCII-specific CD4+ T cells activated in vivo in different contexts. Mice immunized with an immunogenic peptide in adjuvant or infected with lymphocytic choriomeningitis virus or Listeria monocytogenes bacteria induced cytotoxic Th cells that killed B cells displaying relevant p:MHCII complexes. Cytotoxicity was dependent on Fas expression by target cells but was independent of Eomes or perforin expression by T cells. Although the priming regimens induced different proportions of Th1, Th17, regulatory T cells, and T follicular helper cells, the T cells expressed Fas ligand in all cases. Reciprocally, Fas was upregulated on target cells in a p:MHCII-specific manner. These results indicate that many Th subsets have cytotoxic potential that is enhanced by cognate induction of Fas on target cells.
Cell-Specific Requirements for STAT Proteins and Type I IFN Receptor Signaling Discretely Regulate IL-24 and IL-10 Expression in NK Cells and Macrophages
Authors: Dabitao Djeneba , Hedrich Christian M. , Wang Fengying , Vacharathit Vimvara , Bream Jay H. 
Published: February 2018

Abstract
Il10 forms a cytokine cluster with Il19, Il20, and Il24 in a conserved region of chromosome 1. The latter genes are in the IL-20 subfamily of IL-10–related cytokines and, although they are not as well studied their biologic actions and expression patterns, seem to have little in common with IL-10. IL-24, like IL-10, however, is uniquely expressed in T cells and is a signature gene of the Th2 lineage, which suggests they could be coregulated in certain cell types. Little is known about other cellular sources of IL-24. We investigated IL-24 and IL-10 expression in murine macrophages and NK cells, and found that although they are coexpressed under most stimulation conditions, IL-24 and IL-10 are controlled by distinct, cell type–specific pathways. In bone marrow–derived macrophages, optimal IL-24 expression required LPS+IL-4 costimulation and STAT6 but was independent of type I IFN receptor signaling and STAT4. Conversely, LPS-induced IL-10 was independent of IL-4/STAT6 and STAT4 but, consistent with other reports, required type I IFN receptor signaling for optimal expression. Remarkably, NK-specific IL-24 (but not IL-10) expression was dependent on both type I IFN receptor signaling and STAT4. Induction of IL-24 expression was accompanied by cell-specific recruitment of STAT6 and STAT4 to multiple sites that we identified within Il24, which mediated STAT-dependent histone modifications across the gene. Collectively, our results indicate that despite being coexpressed, IL-10 and IL-24 are independently regulated by different type I IFN receptor signaling pathways in innate immune cells and provide insight into the mechanisms that fine-tune cell type–specific gene expression within the Il10 cluster.
Assessing the clogging and permeability of degrading packed bed reactors
Authors: Botes Anthin , James Chris , Sheridan Craig M 
Published: February 2018

In South Africa, the need for water treatment is increasing, especially in the mining sector. As active water treatment technologies are expensive, the mining sector has an increasing need for passive water treatment technology, with low maintenance and operating costs, yet efficient water treatment ability. Literature on passive water treatment suggests that these systems only offer a narrow range of treatment capabilities. Therefore, hybrid water treatment systems could be a solution to low-cost water treatment in South Africa. The degrading packed bed reactor (DPBR) is one of the units comprising the hybrid treatment group. The DPBR’s main action is to convert sulfates into sulfides and alkalinity, since this reduces the impact on the environment by increasing the pH and reducing the salinity. In this study, 6 small-scale DPBRs were constructed. Each was classified according to its unique organic source (manure, straw, vegetable food processing waste, wood shavings, chicken litter and a combined sample with layers of all the carbon sources). Synthetic acid mine drainage (AMD) was fed through the 6 bioreactors for a period of 3 months. Permeabilities, leachate samples and effective void volumes were measured from the DPBRs. From the experiments conducted, it was found that the manure and combination bioreactors (with equal layers of manure, straw, compost, wood shavings and chicken litter) had the lowest overall permeabilities, with straw and compost having the highest permeabilities. Linked to this, the experiments showed that the manure and combination bioreactors had the largest decreases in effective porosity with straw and compost having the least. Hydraulically, the combination bioreactor performed the best by incorporating the best attributes from each carbon source. Wood shavings preformed almost as well. Chicken litter clogged within 18 days after the initiation of the experiment and thus was the least effective substrate.
Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region
Authors: Iwata Ayumi , Matsuki Atsushi 
Published: February 2018

Abstract. In order to better characterize ice nucleating (IN) aerosol
particles in the atmosphere, we investigated the chemical composition, mixing
state, and morphology of atmospheric aerosols that nucleate ice under
conditions relevant for mixed-phase clouds. Five standard mineral dust
samples (quartz, K-feldspar, Na-feldspar, Arizona test dust, and Asian dust
source particles) were compared with actual aerosol particles collected from
the west coast of Japan (the city of Kanazawa) during Asian dust events in February
and April 2016. Following droplet activation by particles deposited on
a hydrophobic Si (silicon) wafer substrate under supersaturated air, individual IN
particles were located using an optical microscope by gradually cooling the
temperature to −30 ∘C. For the aerosol samples, both the IN active
particles and non-active particles were analyzed individually by atomic force
microscopy (AFM), micro-Raman spectroscopy, and scanning electron microscopy
(SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Heterogeneous
ice nucleation in all standard mineral dust samples tested in this study was
observed at consistently higher temperatures (e.g., −22.2 to −24.2 ∘C
with K-feldspar) than the homogeneous freezing temperature (−36.5 ∘C). Meanwhile, most of
the IN active atmospheric particles formed ice below −28 ∘C, i.e.,
at lower temperatures than the standard mineral dust samples of pure
components. The most abundant IN active particles above −30 ∘C
were predominantly irregular solid particles that showed clay mineral
characteristics (or mixtures of several mineral components). Other than clay,
Ca-rich particles internally mixed with other components, such as sulfate,
were also regarded as IN active particle types. Moreover, sea salt particles
were predominantly found in the non-active fraction, and internal mixing with
sea salt clearly acted as a significant inhibiting agent for the ice
nucleation activity of mineral dust particles. Also, relatively pure or fresh
calcite, Ca(NO3)2, and (NH4)2SO4 particles were
more often found in the non-active fraction. In this study, we demonstrated
the capability of the combined single droplet freezing method and thorough
individual particle analysis to characterize the ice nucleation activity of
atmospheric aerosols. We also found that dramatic changes in the particle
mixing states during long-range transport had a complex effect on the ice
nucleation activity of the host aerosol particles. A case study in the Asian
dust outflow region highlighted the need to consider particle mixing states,
which can dramatically influence ice nucleation activity.