bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Search for the 835 Hz Superburst Oscillation Signal in the Regular Thermonuclear Bursts of 4U 1636-536
Authors: van der Wateren Emma , Watts Anna L. , Ootes Laura S. 
Published: April 2019

Abstract
Burst oscillations are brightness asymmetries that develop in the burning ocean during thermonuclear bursts on accreting neutron stars. They have been observed during H/He-triggered (Type I) bursts and carbon-triggered superbursts. The mechanism responsible is not unknown, but the dominant burst oscillation frequency is typically within a few hertz of the spin frequency, where this is independently known. One of the best-studied burst oscillation sources, 4U 1636-536, has oscillations at 581 Hz in both its regular Type I bursts and in one superburst. Recently, however, Strohmayer & Mahmoodifar reported the discovery of an additional signal at a higher frequency, 835 Hz, during the superburst. This higher frequency is consistent with the predictions for several types of global ocean modes, one of the possible burst oscillation mechanisms. If this is the case then the same physical mechanism may operate in the normal Type I bursts of this source. In this paper we report a stacked search for periodic signals in the regular Type I bursts: we found no significant signal at the higher frequency, with upper limits for the single trial root-mean-square fractional amplitude of 0.57(6)%. Our analysis did, however, reveal that the dominant 581 Hz burst oscillation signal is present at a weak level even in the sample of bursts where it cannot be detected in individual bursts. This indicates that any cutoff in the burst oscillation mechanism occurs below the detection threshold of existing X-ray telescopes.
Three-dimensional Simulations of Massive Stars. I. Wave Generation and Propagation
Authors: Edelmann P. V. F. , Ratnasingam R. P. , Pedersen M. G. , Bowman D. M. , Prat V. , Rogers T. M. 
Published: April 2019

Abstract
We present the first three-dimensional (3D), hydrodynamic simulations of the core convection zone (CZ) and extended radiative zone spanning from 1% to 90% of the stellar radius of an intermediate-mass (

) star. This allows us to self-consistently follow the generation of internal gravity waves (IGWs) at the convective boundary and their propagation to the surface. We find that convection in the core is dominated by plumes. The frequency spectrum in the CZ and that of IGW generation is a double power law, as seen in previous two-dimensional (2D) simulations. The spectrum is significantly flatter than theoretical predictions using excitation through Reynolds stresses induced by convective eddies alone. It is compatible with excitation through plume penetration. An empirically determined distribution of plume frequencies generally matches the one necessary to explain a large part of the observed spectrum. We observe waves propagating in the radiation zone and excited standing modes, which can be identified as gravity and fundamental modes. They show similar frequencies and node patterns to those predicted by the stellar oscillation code GYRE. The continuous part of the spectrum fulfills the IGW dispersion relation. A spectrum of tangential velocity and temperature fluctuations close to the surface is extracted, which is directly related to observable brightness variations in stars. Unlike 2D simulations, we do not see the high frequencies associated with wave breaking, likely because the 3D simulations presented in this paper are more heavily damped.
Detectable Molecular Features above Hydrocarbon Haze via Transmission Spectroscopy with JWST: Case Studies of GJ 1214b-, GJ 436b-, HD 97658b-, and Kepler-51b-like Planets
Authors: Kawashima Yui , Hu Renyu , Ikoma Masahiro 
Published: April 2019

Abstract
Some of the exoplanets observed thus far show featureless or flat transmission spectra, possibly indicating the existence of clouds and/or haze in their atmospheres. Thanks to its large aperture size and broad wavelength coverage, the James Webb Space Telescope (JWST) is expected to enable a detailed investigation of exoplanet atmospheres, which could provide important constraints on the atmospheric composition obscured by clouds/haze. Here, we use four warm (≲1000 K) planets suitable for atmospheric characterization via transmission spectroscopy, GJ 1214b, GJ 436b, HD 97658b, and Kepler-51b, as examples to explore molecular absorption features detectable by JWST even in the existence of hydrocarbon haze in the atmospheres. We simulate photochemistry, the growth of hydrocarbon haze particles, and transmission spectra for the atmospheres of these four planets. We find that among the planetary parameters considered, super-Earths with hazy, relatively hydrogen-rich atmospheres are mostly expected to produce detectable molecular absorption features such as a quite prominent CH4 feature at 3.3 μm, even for the extreme case of the most efficient production of photochemical haze. For a planet that has extremely low gravity, such as Kepler-51b, haze particles grow significantly large in the upper atmosphere due to the small sedimentation velocity, resulting in the featureless or flat transmission spectrum in a wide wavelength range. This investigation shows that, in most cases, the transmission spectra with muted features measured by Hubble Space Telescope do not preclude strong features at the longer wavelengths accessible by JWST.
Teenagers, smartphones and digital audio consumption in the age of Spotify
Authors: Pedrero-Esteban Luis Miguel , Barrios-Rubio Andrés , Medina-Ávila Virginia 
Published: April 2019

The consolidation of smartphones as dominant devices for access to digital information and entertainment has redefined the processes of production and commercialization of cultural communication industries. The nature of these screens, which prioritize the visual content over the sound, decisively influences distribution strategies in the audio market: radio operators, streaming music platforms and podcast creators need to adapt their value chains to the habits derived from this mediation, especially in the younger audience. This research identifies the practices of mobile use as an audio receiver among adolescents in Colombia, Spain and Mexico –the most representative countries of Spanish-speaking digital sound consumption– based on a descriptive study on a thousand subjects from 13 to 19 years of age. The results confirm the overwhelming dominance in this music menu in the face of low penetration of radio and podcast word content. The selection is based on personal criteria, with little margin for the prescription of family or friends. There is evidence of the roots of individual listening, linked to the brand and the visibility of audio providers, who are obliged to develop diffusion logics based not only on thematic or genre preferences, but also on the user experience.La consolidación de los smartphones como dispositivos dominantes de acceso a la información y el ocio digital ha redefinido los procesos de producción y comercialización de las industrias culturales de la comunicación. La naturaleza de estas pantallas, que priorizan el contenido visual sobre el sonoro, determina hoy las estrategias de distribución y comercialización en el mercado del audio: operadores de radio, servicios de música en streaming y creadores de podcasts necesitan adecuar sus cadenas de valor a los hábitos derivados de esta mediatización, sobre todo en la audiencia más joven. Esta investigación identifica las prácticas de uso del móvil como receptor de audio entre los adolescentes de Colombia, España y México –los países más representativos del consumo digital sonoro hispanohablante– a partir de un estudio descriptivo sobre 1.004 sujetos de 13 a 19 años. Los resultados revelan el abrumador dominio de la música en este menú frente a la baja aceptación de los contenidos de palabra de radio y podcast. Su selección se asienta sobre criterios personales, con poco margen para la prescripción de familiares o amigos. Se constata el arraigo de una escucha individual, ligada a la marca y la visibilidad de los oferentes de audio, obligados a desarrollar lógicas de difusión basadas no sólo en preferencias de temas o géneros, sino también en las asociadas a la experiencia de usuario en estos terminales.
Quel français enseigner dans les licences professionnelles au Maroc ?
Authors: Bouibhirne Souhail 
Published: April 2019

Depuis leur création en 2005, les licences professionnelles attirent de plus en plus d’étudiants à l’université. Cet engouement est expliqué par les exigences du marché de l’emploi. Néanmoins, l’accès à ces filières professionnelles ne se fait pas sans difficultés ; d’une part les étudiants doivent passer par une présélection sur dossier et d’autre part ils sont censés suivre des cours de spécialité dans une langue étrangère, en l’occurrence le français. Cette dernière difficulté est ressentie par la majorité des étudiants car la langue d’enseignement passe de l’arabe standard au cycle secondaire qualifiant à la langue française au cycle supérieur (pour les filières scientifiques et techniques). Plusieurs mesures ont été effectuées afin de remédier à cette « fracture linguistique », entre autres la création d’un module appelé « langue et terminologie » qui vise essentiellement une remise à niveau linguistique. Or, les profils des étudiants sont très hétéroclites car ils sont issus de différentes filières au baccalauréat (économie, sciences expérimentales, sciences mathématiques etc.) et leur niveau de maitrise de la langue française est loin d’être identique. C’est dans cette perspective que s’inscrit cette contribution qui s’interroge sur la relation entre le cours de français d’une part et les besoins réels de ces étudiants d’autre part. Cette enquête sur terrain nous a permis de constater que l’enseignement d’un français général est loin de répondre à leurs besoins, à la différence d’un français sur objectifs universitaires qui s’avère le mieux adapté à leurs besoins aussi bien langagiers que méthodologiques.
Dlg1 Maintains Dendritic Cell Function by Securing Voltage-Gated K+ Channel Integrity
Authors: Dong Xuejiao , Wei Lisi , Guo Xueheng , Yang Zhiyong , Wu Chuan , Li Peiyu , Lu Lu , Qi Hai , Shi Yan , Hu Xiaoyu , Wu Li , Chen Liangyi , Liu Wanli 
Published: April 2019

Abstract
Dendritic cells (DCs) play key roles in Ab responses by presenting Ags to lymphocytes and by producing proinflammatory cytokines. In this study, we reported that DC-specific knockout of discs large homologue 1 (Dlg1) resulted in a significantly reduced capacity to mediate Ab responses to both thymus-independent and thymus-dependent Ags in Dlg1fl/flCd11c-Cre-GFP mice. Mechanistically, Dlg1-deficient DCs showed severely impaired endocytosis and phagocytosis capacities upon Ag exposure. In parallel, loss of Dlg1 significantly jeopardized the proinflammatory cytokine production by DCs upon TLR stimulation. Thus, Dlg1-deficient DCs lost their functions to support innate and adaptive immunities. At a cellular level, Dlg1 exhibited an indispensable function to maintain membrane potential changes by securing potassium ion (K+) efflux and subsequent calcium ion (Ca2+) influx events in DCs upon stimulation, both of which are known to be required for proper function of DCs. At a molecular level, Dlg1 did so by retaining the integrity of voltage-gated K+ channels (including Kv1.3) in DCs. The loss of Dlg1 led to a decreased expression of K+ channels, resulting in impaired membrane potential changes and, as a consequence, reduced proinflammatory cytokine production, compromised Ag endocytosis, and phagocytosis. In conclusion, this study provided, to our knowledge, a novel insight into Dlg1 and the voltage-gated K+ channels axis in DC functions.
Validation and application of optimal ionospheric shell height model for single-site estimation of total electron content
Authors: Zhao Jiaqi , Zhou Chen 
Published: April 2019

Abstract. We recently proposed a method to establish an optimal ionospheric shell
height model based on the international GNSS service (IGS) station data and
the differential code bias (DCB) provided by the Center for Orbit Determination
in Europe (CODE) during the time from 2003 to 2013. This method is very
promising for DCB and accurate total electron content (TEC) estimation by
comparing to the traditional fixed shell height method. However, this method
is basically feasible only for IGS stations. In this study, we investigate
how to apply the optimal ionospheric shell height derived from IGS station
to non-IGS stations or isolated GNSS receivers. The intuitive and practical
method to estimate TEC of non-IGS stations is based on optimal ionospheric
shell height derived from nearby IGS stations. To validate this method, we
selected two dense networks of IGS stations located in regions in the US and
Europe. Two optimal ionospheric shell height models are established by two
reference stations, namely GOLD and PTBB, which are located at the
approximate center of two selected regions. The predicted daily optimal
ionospheric shell heights by the two models are applied to other IGS
stations around these two reference stations. Daily DCBs are calculated
according to these two optimal shell heights and compared to respective DCBs
released by CODE. The validation results of this method are as follows. (1) Optimal ionospheric shell height calculated by IGS stations can be applied
to its nearby non-IGS stations or isolated GNSS receivers for accurate TEC
estimation. (2) As the distance away from the reference IGS station becomes
larger, the DCB estimation error becomes larger. The relation between the
DCB estimation error and the distance is generally linear.
Utilisation des bases de données médico-administratives du Québec pour des études en
santé mentale : opportunités, défis méthodologiques et limites – cas de la dépression chez
les personnes diabétiques
Authors: Lunghi Carlotta , Zongo Arsène , Guénette Line 
Published: April 2019

L’utilisation des bases de données médico-administratives pour les études sur des
questions de santé mentale est très fréquente compte tenu du grand nombre de personnes
représentées dans ces bases de données et aussi du fait qu’elles portent sur plusieurs
années. Plusieurs défis, liés par exemple à l’identification des personnes ayant une maladie
d’intérêt ou exposées à un facteur de risque, sont à surmonter à travers des études de
validation pour garantir une utilisation optimale de ces ressources. Par ailleurs, des
limites (absence de certaines informations pertinentes) et la couverture d’une seule partie
de la population par le régime public d’assurance médicaments du Québec sont à considérer
dans l’interprétation et la généralisation des résultats des recherches à partir de ces
bases de données.
Dans cet article, nous avons réalisé un survol de l’utilisation des bases de
données médico-administratives pour des études épidémiologiques, en utilisant comme exemple
le cas spécifique de la dépression. Nous avons en particulier utilisé ces bases de données
pour déterminer l’incidence de la dépression parmi les personnes diabétiques du Québec. Cela
a nécessité l’utilisation d’un algorithme préalablement validé (dans une autre province) que
nous avons modifié pour définir et identifier les cas de dépression dans les bases de
données de la Régie de l’assurance maladie du Québec (RAMQ). Nous avons observé une
incidence de dépression de 9,47/1000 personnes-années sur un suivi de 8 ans. Enfin, nous
avons évalué l’impact de la dépression sur l’adhésion et la persistance aux traitements
antidiabétiques ainsi que les facteurs qui affectent l’utilisation des médicaments par ces
patients. Nos résultats suggèrent que la dépression a un impact négatif sur l’utilisation
des médicaments antidiabétiques et permettent d’identifier des pistes de
solution.
Comprehensive classification of the plant non-specific lipid transfer protein superfamily towards its Sequence – Structure – Function analysis.
Authors: Fleury Cecile , Gracy Jerome , Gautier Marie-Francoise , Pons Jean-Luc , Dufayard Jean-Francois , Labesse Gilles , Ruiz Manuel , de Lamotte Frederic 
Published: April 2019

Background. Non-specific Lipid Transfer Proteins (nsLTPs) are widely distributed in the plant kingdom and constitute a superfamily of related proteins. More than 800 different sequences have been characterized so far, but their biological functions remain unclear. It has been clear for years that they present a certain interest for agronomic and nutritional issues. Deciphering their functions means collecting and analyzing a variety of data from gene sequence to protein structure, from cellular localization to the physiological role. As a huge and growing number of new protein sequences are available nowadays, extracting meaningful knowledge from sequence-structure-function relationships calls for the development of new tools and approaches. As nsLTPs show high evolutionary divergence, but a conserved common right-handed superhelix structural fold, and as they are involved in a large number of key roles in plant development and defense, they are a stimulating case study for validating such an approach.
Methods. In this study, we comprehensively investigated 797 nsLTP protein sequences, including a phylogenetic analysis on canonical protein sequences, three-dimensional (3D) structure modeling and functional annotation using several well-established bioinformatics programs. Additionally, two integrative methodologies using original tools were developed. The first was a new method for the detection of i) conserved amino acid residues involved in structure stabilization and ii) residues potentially involved in ligand interaction. The second was a structure-function classification based on the Evolutionary Trace Display method using a new tree visualization interface. We also present a new tool for visualizing phylogenetic trees.
Results. Following this new protocol, an updated classification of the nsLTP superfamily was established and a new functional hypothesis for key residues is suggested. Lastly, this work allows a better representation of the diversity of plant nsLTPs in terms of sequence, structure, and function.
Identification of candidate reference genes for qRT-PCR normalization studies of salinity stress and injury inOnchidium reevesii
Authors: Yang Teizhu , Gu Bingning , Xu Guolyu , Shi Yanmei , Shen Heding , Rao Rongcheng , Mzuka Hellen Lucas 
Published: April 2019

Real-time quantitative reverse transcription-PCR (qRT-PCR) is an undeniably effective tool for measuring levels of gene expression, but the accuracy and reliability of the statistical data obtained depend mainly on the basal expression of selected housekeeping genes in many samples. To date, there have been few analyses of stable housekeeping genes inOnchidium reevesiiunder salinity stress and injury. In this study, the gene expression stabilities of seven commonly used housekeeping genes,CYC,RPL28S,ACTB,TUBB,EF1a,Ubiqand18S RNA, were investigated using BestKeeper, geNorm, NormFinder and RefFinfer. Although the results of the four programs varied to some extent, in general,RPL28S,TUBB,ACTBandEF1awere ranked highly.ACTBandTUBBwere found to be the most stable housekeeping genes under salinity stress, andEF1aplusTUBBwas the most stable combination under injury stress. When analysing target gene expression in different tissues,RPL28SorEF1ashould be selected as the reference gene according to the level of target gene expression. Under extreme environmental stress (salinity) conditions,ACTB(0 ppt, 5 ppt, 15 ppt, 25 ppt) andTUBB(35 ppt) are reasonable reference gene choices when expression stability and abundance are considered. Under conditions of 15 ppt salinity and injury stress, our results showed that the best two-gene combination wasTUBBplusEF1a. Therefore, we suggest thatRPL28S,ACTBandTUBBare suitable reference genes for evaluating mRNA transcript levels. Based on candidate gene expression analysis, the tolerance ofO. reevesiito low salinity (low osmotic pressure) is reduced compared to its tolerance to high salinity (high osmotic pressure). These findings will help researchers obtain accurate results in future quantitative gene expression analyses ofO. reevesiiunder other stress conditions.
MEMORY, MIGRATION AND THE AUTHORITY OF HISTORY IN SOUTHERN TANZANIA, 1860–1960
Authors: MONSON JAMIE 
Published: July 2002

According to their ethnographers, the Bena of the Rivers in colonial
Tanganyika emerged ‘from the shadows into the light of day’ when they
undertook a great migration from the forested hills of the Iringa highlands
to the treeless floodplain of the Kilombero valley in the late 1800's. The
phrase had two meanings – on one level, it described the physical relocation
of the Bena from the shadows of the forest to the open floodplain. On another
level, ‘light of day’ was a metaphor for the remembered cohesion of a distinct
Bena tribal identity, distinguishable from the ‘shadows’ of prior ethnic
obscurity. The Culwicks considered the chief or mtema of this period,
Ndaliwali, to be the founding ancestor of a new political lineage.The defining moment for the emergence of the Bena of the Rivers was the
Battle of Mgodamtitu in 1874, when neighboring Hehe attacked Bena
settlements in the foothills and forced the Bena permanently out of the
highlands and into the valley. Once they had taken up their new residence,
the Bena absorbed the existing settlements of the western end of the valley
into their kingdom. They did this initially ‘under the guise of protector’,
wrote the Culwicks, but their goal was political control of the region. By
1890, they wrote, most of the Ndamba as well as several smaller valley groups
had become subjects of the Bena chief.The Battle of Mgodamtitu caused a ‘sudden and wholesale change’,
according to the Culwicks, because Bena were forced to give up cattle
keeping and take up rice cultivation; to learn the ways of the river and skillful
use of canoes. They had previously looked down upon ‘rice and fish-eaters’,
but after their migration they found that ‘there is but one crop really worth
growing, and that is rice’.