bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Constraints on IGM Thermal Evolution from the Lyα Forest Power Spectrum
Authors: Walther Michael , Oñorbe Jose , Hennawi Joseph F. , Lukić Zarija 
Published: February 2019

Abstract
We determine the thermal evolution of the intergalactic medium (IGM) over 3 Gyr of cosmic time

by comparing measurements of the Lyα forest power spectrum to a suite of ∼70 hydrodynamical simulations. We conduct Bayesian inference of IGM thermal parameters using an end-to-end forward modeling framework whereby mock spectra generated from our simulation grid are used to build a custom emulator that interpolates the power spectrum between thermal grid points. The temperature at mean density T
0 rises steadily from

at z = 5.4, peaks at 14,000 K for z ∼ 3.4, and decreases at lower redshift, reaching T
0 ∼ 7000 K by z ∼ 1.8. This evolution provides conclusive evidence for photoionization heating resulting from the reionization of

, as well as the subsequent cooling of the IGM due to the expansion of the universe after all reionization events are complete. Our results are broadly consistent with previous measurements of thermal evolution based on a variety of approaches, but the sensitivity of the power spectrum, the combination of high-precision measurements of large-scale modes (

) from the Baryon Oscillation Spectroscopic Survey with our recent determination of the small-scale power, our large grid of models, and our careful statistical analysis allow us to break the well-known degeneracy between the temperature at mean density T
0 and the slope of the temperature–density relation γ that has plagued previous analyses. At the highest redshifts, z ≥ 5, we infer lower temperatures than expected from the standard picture of IGM thermal evolution leaving little room for additional smoothing of the Lyα forest by free streaming of warm dark matter.
Strong Gravitational Lensing by Wave Dark Matter Halos
Authors: Herrera-Martín Antonio , Hendry Martin , Gonzalez-Morales Alma X. , Ureña-López L. Arturo 
Published: February 2019

Abstract
Wave dark matter (WaveDM) has recently gained attention as a viable candidate to account for the dark matter content of the universe. In this paper we explore the extent to which, and under what conditions, dark matter halos in this model are able to reproduce strong-lensing systems. First, we explore analytically the lensing properties of the model, finding that a pure WaveDM density profile, the soliton profile, produces a weaker lensing effect than similar cored profiles. Then, we analyze models with a soliton embedded within a Navarro, Frenk, and White (NFW) profile, as has been found in numerical simulations of structure formation. We use a benchmark model with a boson mass of m

a
= 10−22 eV, for which we see that there is a bimodality in the contribution of the external NFW part of the profile, and some of the free parameters associated with it are not well constrained. We find that for configurations with boson masses 10−23 to 10−22 eV, a range of masses preferred by dwarf galaxy kinematics, the soliton profile alone can fit the data, but its size is incompatible with the luminous extent of the lens galaxies. Likewise, boson masses of the order of 10−21 eV, which would be consistent with Lyα constraints and consist of more compact soliton configurations, necessarily require the NFW part in order to reproduce the observed Einstein radii. We then conclude that lens systems impose a conservative lower bound m

a
> 10−24 eV and that the NFW envelope around the soliton must be present to satisfy the observational requirements.
Compton-thick AGNs in the NuSTAR Era. III. A Systematic Study of the Torus Covering Factor
Authors: Marchesi S. , Ajello M. , Zhao X. , Marcotulli L. , Baloković M. , Brightman M. , Comastri A. , Cusumano G. , Lanzuisi G. , La Parola V. , Segreto A. , Vignali C. 
Published: February 2019

Abstract
We present the analysis of a sample of 35 candidate Compton-thick active galactic nuclei (AGNs) selected in the nearby universe (average redshift

) with the Swift-BAT 100-month survey. All sources have available NuSTAR data, thus allowing us to constrain with unprecedented quality important spectral parameters such as the obscuring torus line-of-sight column density (N
H,z), the average torus column density (N
H,tor), and the torus covering factor (f

c
). We compare the best-fit results obtained with the widely used MYTorus (Murphy & Yaqoob 2009) model with those of the recently published borus02 model (Baloković et al. 2018) used in the same geometrical configuration of MYTorus (i.e., with f

c
= 0.5). We find a remarkable agreement between the two, although with increasing dispersion in N
H,z moving toward higher column densities. We then use borus02 to measure f

c
. High-f

c
sources have, on average, smaller offset between N
H,z and N
H,tor than low-f

c
ones. Therefore, low f

c
values can be linked to a “patchy torus” scenario, where the AGN is seen through an overdense region in the torus, while high-f

c
objects are more likely to be obscured by a more uniform gas distribution. Finally, we find potential evidence of an inverse trend between f

c
and the AGN 2–10 keV luminosity, i.e., sources with higher f

c
values have on average lower luminosities.
Effects of Gas on Formation and Evolution of Stellar Bars and Nuclear Rings in Disk Galaxies
Authors: Seo Woo-Young , Kim Woong-Tae , Kwak SungWon , Hsieh Pei-Ying , Han Cheongho , Hopkins Phil F. 
Published: February 2019

Abstract
We run self-consistent simulations of Milky Way-sized, isolated disk galaxies to study the formation and evolution of a stellar bar as well as a nuclear ring in the presence of gas. We consider two sets of models with cold or warm disks that differ in the radial velocity dispersions, and vary the gas fraction

by fixing the total disk mass. A bar forms earlier and more strongly in the cold disks with larger

, while gas progressively delays the bar formation in the warm disks. The bar formation enhances a central mass concentration, which in turn causes the bar to decay temporarily, after which it regrows in size and strength, eventually becoming stronger in models with smaller

. Although all bars rotate fast in the beginning, they rapidly turn to slow rotators. In our models, only the gas-free, warm disk undergoes rapid buckling instability, while other disks thicken more gradually via vertical heating. The gas driven inward by the bar potential readily forms a star-forming nuclear ring. The ring is very small when it first forms and grows in size over time. The ring star formation rate is episodic and bursty due to feedback, and is well correlated with the mass inflow rate to the ring. Some expanding shells produced by star formation feedback are sheared out in the bar regions and collide with dust lanes to appear as filamentary interbar spurs. The bars and nuclear rings formed in our simulations have properties similar to those in the Milky Way.
Particle Acceleration at 5 au Associated with Turbulence and Small-scale Magnetic Flux Ropes
Authors: Zhao L.-L. , Zank G. P. , Chen Y. , Hu Q. , le Roux J. A. , Du S. , Adhikari L. 
Published: February 2019

Abstract
An observational analysis of an atypical energetic particle event near 5 au measured by the Ulysses spacecraft is presented. A previous study has attributed the unusual enhancement of energetic proton flux to the presence of small-scale dynamic magnetic islands or flux ropes. Here, we find that the generation of these magnetic islands may be related to the interaction of a stream interaction region (SIR) and the heliospheric current sheet (HCS). Particles are accelerated and trapped within the SIR structure characterized by a forward shock–reverse wave pair. Analysis of the energetic particle intensity spectra shows that the 63 keV–4.4 MeV protons form a power-law (PL) spectrum near the shock, with a slope much steeper than predicted by the diffusive shock acceleration (DSA) theory. Double PL spectra are found in the region of unusual particle flux enhancement, and the lower energy part of the spectrum gets harder farther away from the shock. In comparison, we discuss a later forward wave–reverse wave pair with an embedded large-scale magnetic cloud (MC). In contrast to small-scale magnetic islands, the MC corresponds to a decrease in energetic proton fluxes. A power spectral density analysis suggests that the turbulence level increases in the compression regions, and the majority of the observed turbulence power resides in the two-dimensional (2D) component because the spacecraft velocity is almost perpendicular to the interplanetary magnetic field. This is consistent with the enhanced generation of magnetic flux ropes, which are instrinsic to quasi-2D MHD turbulence, in the SIR. An automatic Grad–Shafranov reconstruction technique is used to identify flux rope structures within the period of interest, and their detailed parameters are included in the paper. The observational evidence suggests that the interaction of shock/compressional waves with the HCS may be a key element in generating small-scale dynamic magnetic islands, which subsequently accelerate charged particles and complement the classical DSA mechanism.
The Signature of a Windy Radio Supernova Progenitor in a Binary System
Authors: Yalinewich Almog , Zwart Simon Portegies 
Published: February 2019

Abstract
Type II supernova progenitors are expected to emit copious amounts of mass in a dense stellar wind prior to the explosion. When the progenitor is a member of a binary, the orbital motion modulates the density of this wind. When the progenitor explodes, the high-velocity ejecta collides with the modulated wind, which in turn produces a modulated radio signal. In this Letter we derive general analytic relations between the parameters of the radio signal modulations and binary parameter in the limit of large member-mass ratio. We use these relations to infer the semimajor axis of SN 1979c and a lower bound for the mass of the companion. We further constrain the analytic estimates by numerical simulations using the Astrophysical Multipurpose Software Environment framework. In these calculations we simulate the progenitor binary system including the wind and the gravitational effect of a companion star. The simulation output is compared to the observed radio signal in supernova SN 1979C. We find that it must have been a binary with an orbital period of about 2000 yr. If the exploding star evolved from a ∼18 M
⊙ zero-age main sequence at solar metallicity, we derive a companion mass of 5–12 M
⊙ in an orbit with an eccentricity lower than about 0.8.
Foodborne disease outbreaks in Barbados (1998-2009): a 12-year review
Authors: Hull-Jackson Carol , Adesiyun Abiodun A 
Published: February 2019

Introduction: Microbes such as Salmonella, Campylobacter and S. aureus have been implicated in Foodborne disease outbreaks (FBDOs) worldwide, yet information on their occurrence in Barbados is scanty. The purpose of this study was to determine the aetiological agents, food vehicles, locations and peak seasons of FBDOs in Barbados; assess the quality of epidemiological investigations; and identify deficiencies in food production practices and laboratory detection.
Methodology: A search of FBDOs occurring in Barbados between 1998-2009 was conducted among published and unpublished literature sources and reports. The search terms included the keywords “foodborne disease,” “outbreaks” and “Barbados”.
Results: During the period 1998 to 2009, there were 24 foodborne outbreaks, 215 cases of illness, one hospitalisation and no deaths. Overall, 37.5% of outbreaks were associated with hotels/resorts. Salmonella Enteritidis phage type 8 was most commonly implicated with eggs and poultry being the primary vehicles. Three outbreak reports were available for assessment and revealed that there were deficiencies in the outbreak investigations. These reports also recorded high levels of food contamination with indicator organisms, suggesting that improvements in food hygiene and production practices were required.
Conclusions: The number of FBDOs is low in comparison to developed countries. However, the data was likely affected by under-reporting and inadequacies in the outbreak investigations and laboratory detection. Improvements in these areas would lead to not only better detection and characterisation of FBDOs in Barbados but improved food safety control measures.
Argentinian multicenter study on urinary tract infections due to Streptococcus agalactiae in adult patients
Authors: Vigliarolo Laura , Arias Barbara , Suárez Mariana , Van Haute Evert , Kovacec Verónica , Lopardo Horacio , Bonofiglio Laura , Mollerach Marta 
Published: February 2019

Introduction: Streptococcus agalactiae (group B streptococcus, GBS) is a recognized urinary pathogen both in males and pregnant or non-pregnant women. Data regarding GBS serotypes recovered from urinary tract infections (UTIs) are scarce. The aim of this study was to describe the clinical and microbiological characteristics of UTIs caused by GBS in adult patients in Argentina.
Methodology: A prospective multicenter study involving 86 centers was conducted in Argentina between July 1st, 2014 and June 30th, 2015. Antimicrobial susceptibility and serotype distribution of GBS isolated from the urinary tract of adult patients were determined. Susceptibility tests were performed by the disk diffusion and/or agar dilution methods. Epidemiological and clinical characteristics of the patients were considered to identify associated comorbilities.
Results: Seven hundred and one GBS were sent to the reference laboratory in the above mentioned period, however, only 211 fulfilled our selection criteria (demographic data availability, underlying diseases reported, colony counts greater than 105 CFU/mL, single organism isolated from the urine sample). No penicillin-resistant GBS was found but fluoroquinolone resistance was high (12.8%), especially among GBS isolated from men and non-pregnant women. UTIs due to GBS were associated to underlying diseases in men and non-pregnant women, particularly diabetes mellitus. Most of the isolates showed serotypes Ia and III.
Conclusions: GBS are still susceptible to penicillin but fluoroquinolone resistance is a growing concern, at least in Argentina. There are underlying conditions that could be associated to urinary infections caused by GBS.
β-lactamase genes in carbapenem resistance Acinetobacter baumannii isolates from a Turkish university hospital
Authors: Say Coskun Umut Safiye , Caliskan Emel , Copur Cicek Asegul , Turumtay Halbay , Sandalli Cemal 
Published: February 2019

Introduction: The spread of Acinetobacter baumannii, resistant to most of the available antimicrobial agents, is a serious health problem. The high rate of carbapenem resistance among Acinetobacter baumannii isolates is considered as a threat to public health. In this study, we aimed to determine the antibiotic resistance and related genes in carbapenem-resistant Acinetobacter baumannii isolates.
Methodology: Ninety six isolates of A. baumannii were included. Antimicrobial susceptibility was performed by Phoenix Automated System and disk diffusion method. Carbapenem resistane was characterized by scrneeing of resistance genes such as blaTEM, blaSHV, blaCTX-M1-2, blaPER, blaVEB, blaKPC, blaGES, blaNDM, blaVIM, blaIMP and blaOXA23-24-51-58 using multiplex polymerase chain reaction.
Results: Resistance for the levofloxacin, gentamicin, amikacin, and tigecycline were determined as 96.9%, 93.7%, 72.9% and 45.8% respectively. Colistin was the only susceptible antibiotic against all clinical isolates. All isolates were defined as multidrug resistance and of these, 31.2% were extensively drug-resistant (sensitive only to colistin). BlaOXA-51­ and blaOXA-23 genes were detected in 100% strains while blaTEM was found in only 2% strains. There was no amplification for the blaSHV, blaCTX-M1-2, blaPER, blaVEB, blaKPC, blaGES blaNDM, blaVIM, blaIMP and blaOXA24-58 genes.
Conclusions: The high frequency of blaOXA-23 and low frequency of blaTEM gene was observed that indicate prevalence of a variety of A. baumannii strains. The rates of resistance genes vary from region to region. Studies are required for the prevention and control of A. baumannii infection and to formulate the strategies of antibiotic usage.
Fosfomycin in the treatment of extended spectrum beta-lactamase-producing Enterobacteriaceae- related urinary tract infections
Authors: Tumturk Ayhanim , Tonyali Senol , Tezer Tekce Ayse Yasemin , Isikay Levent , Cime Hakan 
Published: February 2019

Introduction: We aimed to demonstrate if fosfomycin tromethamine (FT) treatment could be the treatment of choice in ESBL-producing Enterobacteriaceae strains as an alternative to carbapenem particularly in patients who we would like to treat on an outpatient basis.
Methodology; We retrospectively analyzed the medical records of all patients who admitted to infectious disease outpatient clinic with complaints of dysuria and frequency and received FT for lower UTI between May 2016 and May 2017.
Results: A total of 48 patients, 19 females (39.6%) and 29 males (60.4%), with a mean age of 62.5 (ranging from 27 to 85) years were included the study. 26 (76.4%) of patients with a history of urinary operation or intervention had also a history of antibiotic use within the past 3 months. The isolated pathogens included Escherichia Coli (n = 32), Klebsiella spp. (n = 12), Enterobacter spp. (n = 4). The overall microbiological response after treatment was 70.8% (34/48) and the clinical response was 75% (36/48). Clinical and microbiological response rates of patients with and without urinary operation/intervention, diabetes mellitus, history of antibiotic use and malignancy were found similar (p > 0.05). However, patients with a urinary stone disease history had significantly higher response rates than those without a urinary stone disease history (P = 0.042).
Conclusion: Oral fosfomycin tromethamine might be the treatment of choice in ESBL-producing enterobactericea related UTIs especially caused by Escherichia Coli.
Content syndication in news aggregators. Towards devaluation of professional journalistic criterio
Authors: Edo Concha , Yunquera Juan , Bastos Helder 
Published: February 2019

The growing expansion of Internet access and mass-scale usage of social networking platforms and search engines have forced digital newspapers to deal with challenges, amongst which are the need to constantly update news, the increasing complexity of sources, the difficulty of exercising their function as gatekeepers in a fragmented environment in which the opinions, biases and preconceptions of pundits, their followers, Twitter users, etc. has taken on a new and decisive weight and the mounting pressure to publish certain news items simply because they sell. They must also share audiences with aggregators devoted to the business of disseminating content produced by digital news publishers, blogs and RSS feeds, which is chosen on the basis of search engine algorithms, the votes of users or the preferences of readers. The fact that these computerized systems of news distribution seldom employ the criteria upon which journalism is based suggests that the work of gatekeeping is being reframed in a way that progressively eliminates journalists from the process of deciding what is newsworthy. This study of these trends has entailed a 47 point assessment of 30 news aggregators currently providing syndicated content and eight semi-structured interviews with editors of quality mass-distribution digital newspapers published in the U.S., Spain and Portugal.
La creciente expansión del acceso a Internet y el uso masivo de las plataformas de redes sociales y los motores de búsqueda han obligado a los medios digitales a enfrentarse a desafíos como la necesidad de actualizar constantemente las noticias, la creciente complejidad de las fuentes, la dificultad de ejercer su función de «gatekeeper» en un entorno fragmentado en el que las opiniones, los prejuicios y las ideas preconcebidas de los expertos y sus seguidores, los usuarios de Twitter, etc. han adquirido un peso nuevo y decisivo, y la creciente presión para publicar ciertas noticias simplemente porque venden. Tienen además que compartir audiencias con agregadores cuyo negocio consiste en difundir contenido producido por editores de noticias digitales, blogs y «feeds» RSS, que hacen la selección basándose en algoritmos de búsqueda, en los votos de los usuarios o en las preferencias de los lectores. El hecho de que estos sistemas computarizados de distribución de noticias rara vez tienen en cuenta criterios periodísticos sugiere que ese trabajo de selección se está replanteando de tal manera que se va eliminando progresivamente a los periodistas del proceso de decidir lo que tiene interés periodístico. Este estudio sobre las tendencias descritas se ha llevado a cabo mediante la evaluación de 47 parámetros en 30 agregadores de noticias que actualmente ofrecen contenido sindicado, y se ha completado con ocho entrevistas semiestructuradas con editores de medios digitales de calidad y de difusión elevada publicados en los EEUU, España y Portugal.
Constructing Donald Trump: Mobile apps in the political discourse about the President of the United States
Authors: Gómez-García Salvador , Gil-Torres Alicia , Carrillo-Vera José-Agustín , Navarro-Sierra Nuria 
Published: February 2019

This paper explores the creation and content of apps about Donald Trump (n=412) published in Google Play between June 2015 and January 2018. The relevance of the study stems from both its objectives and its methodology. On the one hand, the aim was to characterise the profile, motivations and purposes of the developers of Donald Trump apps; and on the other, to identify the main features of the discourses in the most downloaded apps. The study relied on two resources: a qualitative questionnaire of open questions for developers (n=376), and a quantitative analysis of the content of apps that exceeded 5,000 downloads (n=117). The questionnaire identified the influence of political current affairs in the developers’ ideological and economic motivations, while the content analysis revealed the trends found over time, as well as the themes, discourses and ideological positioning of the most popular apps about Donald Trump. The findings provide an empirical basis for how the content of these apps was articulated with the news; the influence of content that went viral; hegemonic discourses; and the role played by developers of new expressive, commercial, informative and persuasive proposals in the intersection between mobile apps and political campaigns.
Esta investigación explora la creación y el mensaje de las apps sobre Donald Trump publicadas en la plataforma Google Play desde junio de 2015 hasta enero de 2018 (n=412). El interés del estudio proviene tanto de sus objetivos como de su metodología. Por un lado, se pretende detectar el perfil, motivaciones y propósitos de los desarrolladores de apps sobre la figura de Donald Trump y, por otro, identificar los principales rasgos de los discursos de las apps más descargadas. La investigación se ha desarrollado en dos frentes: un cuestionario cualitativo de preguntas abiertas a desarrolladores (n=376) y un análisis cuantitativo de contenido del mensaje de las apps que superaron las 5.000 descargas (n=117). El cuestionario ha identificado la influencia de la actualidad política en los desarrolladores y sus motivaciones de corte ideológico y económico mientras que el análisis de contenido ha revelado la tendencia y evolución de los temas, discursos y el posicionamiento ideológico de las apps más populares sobre Donald Trump. Los resultados establecen una base empírica en relación a la articulación del mensaje de las apps con la actualidad informativa, la influencia de los contenidos virales, los discursos hegemónicos y el rol de los desarrolladores de nuevas propuestas expresivas, comerciales, informativas y persuasivas en la conjunción de los ecosistemas de aplicaciones móviles y las campañas políticas.