bluuebunny/crossref_metadata_2025 huggingface dataset:
BAT AGN Spectroscopic Survey. I. Spectral Measurements, Derived Quantities, and AGN Demographics
Authors: Koss Michael , Trakhtenbrot Benny , Ricci Claudio , Lamperti Isabella , Oh Kyuseok , Berney Simon , Schawinski Kevin , Baloković Mislav , Baronchelli Linda , Crenshaw D. Michael , Fischer Travis , Gehrels Neil , Harrison Fiona , Hashimoto Yasuhiro , Hogg Drew , Ichikawa Kohei , Masetti Nicola , Mushotzky Richard , Sartori Lia , Stern Daniel , Treister Ezequiel , Ueda Yoshihiro , Veilleux Sylvain , Winter Lisa
Published: November 2017

We present the first catalog and data release of the Swift-BAT AGN Spectroscopic Survey. We analyze optical spectra of the majority of the detected AGNs (77%, 642/836)based on their 14–195 keV emission in the 70-month Swift-BAT all-sky catalog. This includes redshift determination, absorption and emission-line measurements, and black hole mass and accretion rate estimates for the majority of obscured and unobscured AGNs (74%, 473/642), with 340 measured for the first time. With ∼90% of sources at

, the survey represents a significant advance in the census of hard X-ray-selected AGNs in the local universe. In this first catalog paper, we describe the spectroscopic observations and data sets, and our initial spectral analysis. The FWHMs of the emission lines show broad agreement with the X-ray obscuration (∼94%), such that Sy 1–1.8 have

cm−2, and Seyfert 2 have

cm−2. Seyfert 1.9, however, show a range of column densities. Compared to narrow-line AGNs in the SDSS, the X-ray-selected AGNs have a larger fraction of dusty host galaxies (

), suggesting that these types of AGN are missed in optical surveys. Using the [O iii] λ5007/Hβ and [N ii] λ6583/Hα emission-line diagnostic, about half of the sources are classified as Seyferts; ∼15% reside in dusty galaxies that lack an Hβ detection, but for which the upper limits on line emission imply either a Seyfert or LINER,

are in galaxies with weak or no emission lines despite high-quality spectra, and a few percent each are LINERS, composite galaxies, H ii regions, or in known beamed AGNs.
A New 3D Multi-fluid Dust Model: A Study of the Effects of Activity and Nucleus Rotation on Dust Grain Behavior at Comet 67P/Churyumov–Gerasimenko
Authors: Shou Y. , Combi M. , Toth G. , Tenishev V. , Fougere N. , Jia X. , Rubin M. , Huang Z. , Hansen K. , Gombosi T.
Published: November 2017

Improving our capability to interpret observations of cometary dust is necessary to deepen our understanding of the role of dust in the formation of comets and in altering the cometary environments. Models including dust grains are in demand to interpret observations and test hypotheses. Several existing models have taken into account the gas–dust interaction, varying sizes of dust grains and the cometary gravitational force. In this work, we develop a multi-fluid dust model based on the BATS-R-US code. This model not only incorporates key features of previous dust models, but also has the capability of simulating time-dependent phenomena. Since the model is run in the rotating comet reference frame, the centrifugal and Coriolis forces are included. The boundary conditions on the nucleus surface can be set according to the distribution of activity and the solar illumination. The Sun revolves around the comet in this frame. A newly developed numerical mesh is also used to resolve the real-shaped nucleus in the center and to facilitate prescription of the outer boundary conditions that accommodate the rotating frame. The inner part of the mesh is a box composed of Cartesian cells and the outer surface is a smooth sphere, with stretched cells filled in between the box and the sphere. Our model achieved comparable results to the Direct Simulation Monte Carlo method and the Rosetta/OSIRIS observations. It is also applied to study the effects of the rotating nucleus and the cometary activity and offers interpretations of some dust observations of comet 67P/Churyumov–Gerasimenko.
A Detailed Study of the Interstellar Protons toward the TeV γ-Ray SNR RX J0852.0–4622 (G266.2–1.2, Vela Jr.): The Third Case of the γ-Ray and ISM Spatial Correspondence
Authors: Fukui Y. , Sano H. , Sato J. , Okamoto R. , Fukuda T. , Yoshiike S. , Hayashi K. , Torii K. , Hayakawa T. , Rowell G. , Filipović M. D. , Maxted N. , McClure-Griffiths N. M. , Kawamura A. , Yamamoto H. , Okuda T. , Mizuno N. , Tachihara K. , Onishi T. , Mizuno A. , Ogawa H.
Published: November 2017

We present a new analysis of the interstellar protons toward the TeV γ-ray SNR RX J0852.0−4622 (G266.2−1.2, Vela Jr.). We used the NANTEN2 12CO(J = 1–0) and Australia Telescope Compact Array and Parkes H i data sets in order to derive the molecular and atomic gas associated with the TeV γ-ray shell of the SNR. We find that atomic gas over a velocity range from V
LSR = −4 to 50 km s−1 or 60 km s−1 is associated with the entire SNR, while molecular gas is associated with a limited portion of the SNR. The large velocity dispersion of the H i is ascribed to the expanding motion of a few H i shells overlapping toward the SNR but is not due to the Galactic rotation. The total masses of the associated H i and molecular gases are estimated to be

M
⊙ and ∼103
M
⊙, respectively. A comparison with the High Energy Stereoscopic System TeV γ-rays indicates that the interstellar protons have an average density around 100 cm−3 and shows a good spatial correspondence with the TeV γ-rays. The total cosmic-ray proton energy is estimated to be ∼1048 erg for the hadronic γ-ray production, which may still be an underestimate by a factor of a few due to a small filling factor of the SNR volume by the interstellar protons. This result presents a third case, after RX J1713.7−3946 and HESS J1731−347, of the good spatial correspondence between the TeV γ-rays and the interstellar protons, lending further support for a hadronic component in the γ-rays from young TeV γ-ray SNRs.
Gas-phase Absorptions of
near 8300 Å below 10 K: Astronomical Implications
Authors: Campbell E. K. , Maier J. P.
Published: November 2017

The gas-phase electronic spectrum of

(

) with an origin band at

has been measured below

by photofragmentation of helium complexes (

) in a radiofrequency trap.

is a medium-sized polycyclic aromatic hydrocarbon (PAH) cation, and using an ion trapping technique it has been possible to record a high-quality gas-phase spectrum to directly compare with astronomical observations. No diffuse interstellar bands (DIBs) have been reported at the wavelengths of the strongest absorption bands in the

spectrum. Measurement of absolute absorption cross sections in the ion trap allows upper limits to the column density of this ion to be

, indicating that even PAH cations of this size, which are believed to be stable in the interstellar medium, should be excluded as candidates for at least the strong DIBs.
Calibrating Star Formation in WISE Using Total Infrared Luminosity
Authors: Cluver M. E. , Jarrett T. H. , Dale D. A. , Smith J.-D. T. , August Tamlyn , Brown M. J. I.
Published: November 2017

We present accurate resolved WISE photometry of galaxies in the combined SINGS and KINGFISH sample. The luminosities in the W3 12 μm and W4 23 μm bands are calibrated to star formation rates (SFRs) derived using the total infrared luminosity, avoiding UV/optical uncertainties due to dust extinction corrections. The W3 relation has a 1σ scatter of 0.15 dex that is over nearly 5 orders of magnitude in SFR and 12 μm luminosity, and a range in host stellar mass from dwarfs (107

) to

(1011.5

) galaxies. In the absence of deep silicate absorption features and powerful active galactic nuclei, we expect this to be a reliable SFR indicator chiefly due to the broad nature of the W3 band. By contrast, the W4 SFR relation shows more scatter (1

dex). Both relations show reasonable agreement with radio-continuum-derived SFRs and excellent accordance with so-called “hybrid” Hα + 24 μm and FUV+24 μm indicators. Moreover, the WISE SFR relations appear to be insensitive to the metallicity range in the sample. We also compare our results with IRAS-selected luminous infrared galaxies, showing that the WISE relations maintain concordance, but systematically deviate for the most extreme galaxies. Given the all-sky coverage of WISE and the performance of the W3 band as an SFR indicator, the

SFR relation could be of great use to studies of nearby galaxies and forthcoming large-area surveys at optical and radio wavelengths.
Rapid Formation of Black Holes in Galaxies: A Self-limiting Growth Mechanism
Authors: Li Zhi , Sellwood J. A. , Shen Juntai
Published: November 2017

We present high-quality fluid dynamical simulations of isothermal gas flows in a rotating barred potential. We show that a large quantity of gas is driven right into the nucleus of a galaxy when the model lacks a central mass concentration, but the inflow stalls at a nuclear ring in comparison simulations that include a central massive object. The radius of the nuclear gas ring increases linearly with the mass of the central object. We argue that bars drive gas right into the nucleus in the early stages of disk galaxy formation, where a nuclear star cluster and perhaps a massive black hole could be created. The process is self-limiting, however, because inflow stalls at a nuclear ring once the mass of gas and stars in the nucleus exceeds ∼1% of the disk mass, which shuts off rapid growth of the black hole. We briefly discuss the relevance of these results to the seeding of massive black holes in galaxies, the merger model for quasar evolution, and the existence of massive black holes in disk galaxies that lack a significant classical bulge.
Characterizing the Motion of Solar Magnetic Bright Points at High Resolution
Authors: Van Kooten Samuel J. , Cranmer Steven R.
Published: November 2017

Magnetic bright points in the solar photosphere, visible in both continuum and G-band images, indicate footpoints of kilogauss magnetic flux tubes extending to the corona. The power spectrum of bright-point motion is thus also the power spectrum of Alfvén wave excitation, transporting energy up flux tubes into the corona. This spectrum is a key input in coronal and heliospheric models. We produce a power spectrum of bright-point motion using radiative magnetohydrodynamic simulations, exploiting spatial resolution higher than can be obtained in present-day observations, while using automated tracking to produce large data quantities. We find slightly higher amounts of power at all frequencies compared to observation-based spectra, while confirming the spectrum shape of recent observations. This also provides a prediction for observations of bright points with DKIST, which will achieve similar resolution and high sensitivity. We also find a granule size distribution in support of an observed two-population distribution, and we present results from tracking passive tracers, which show a similar power spectrum to that of bright points. Finally, we introduce a simplified, laminar model of granulation, with which we explore the roles of turbulence and of the properties of the granulation pattern in determining bright-point motion.
Feeding versus Falling: The Growth and Collapse of Molecular Clouds in a Turbulent Interstellar Medium
Authors: Ibáñez-Mejía Juan C. , Mac Low Mordecai-Mark , Klessen Ralf S. , Baczynski Christian
Published: November 2017

In order to understand the origin of observed molecular cloud (MC) properties, it is critical to understand how clouds interact with their environments during their formation, growth, and collapse. It has been suggested that accretion-driven turbulence can maintain clouds in a highly turbulent state, preventing runaway collapse and explaining the observed non-thermal velocity dispersions. We present 3D, adaptive-mesh-refinement, magnetohydrodynamical simulations of a kiloparsec-scale, stratified, supernova-driven, self-gravitating, interstellar medium (ISM), including diffuse heating and radiative cooling. These simulations model the formation and evolution of a MC population in the turbulent ISM. We use zoom-in techniques to focus on the dynamics of the mass accretion and its history for individual MCs. We find that mass accretion onto MCs proceeds as a combination of turbulent flow and near free-fall accretion of a gravitationally bound envelope. Nearby supernova explosions have a dual role, compressing the envelope and increasing mass accretion rates, but also disrupting parts of the envelope and eroding mass from the cloud’s surface. It appears that the inflow rate of kinetic energy onto clouds from supernova explosions is insufficient to explain the net rate of change of the cloud kinetic energy. In the absence of self-consistent star formation, the conversion of gravitational potential into kinetic energy during contraction seems to be the main driver of non-thermal motions within clouds. We conclude that although clouds interact strongly with their environments, bound clouds are always in a state of gravitational contraction, close to runaway, and their properties are a natural result of this collapse.
Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. II. Prominence Bubble Boundary Layer Characteristics and the Onset of a Coupled Kelvin–Helmholtz Rayleigh–Taylor Instability
Authors: Berger Thomas , Hillier Andrew , Liu Wei
Published: November 2017

We analyze solar quiescent prominence bubble characteristics and instability dynamics using Hinode/Solar Optical Telescope data. We measure the bubble expansion rate, prominence downflows, and the profile of the boundary layer brightness and thickness as a function of time. The largest bubble analyzed rises into the prominence with a speed of about

1.3

km

s

−
1

until it is destabilized by a localized shear flow on the boundary. Boundary layer thickness grows gradually as prominence downflows deposit plasma onto the bubble with characteristic speeds of

20
–
35

km

s

−
1

. Lateral downflows initiate from the thickened boundary layer with characteristic speeds of

25
–
50

km

s

−
1

, “draining” the layer of plasma. Strong shear flow across one bubble boundary leads to an apparent coupled Kelvin–Helmholtz Rayleigh–Taylor (KH–RT) instability. We measure shear flow speeds above the bubble of

10

km

s

−
1

and infer interior bubble flow speeds on the order of

100

km

s

−
1

. Comparing the measured growth rate of the instability to analytic expressions, we infer a magnetic flux density across the bubble boundary of ∼10−3 T (10 Gauss) at an angle of

∼
70
°

to the prominence plane. The results are consistent with the hypothesis that prominence bubbles are caused by magnetic flux that emerges below a prominence, setting up the conditions for RT, or combined KH–RT, instability flows that transport flux, helicity, and hot plasma upward into the overlying coronal magnetic flux rope.
Pre-explosion Spiral Mass Loss of a Binary Star Merger
Authors: Pejcha Ondřej , Metzger Brian D. , Tyles Jacob G. , Tomida Kengo
Published: November 2017

Binary stars commonly pass through phases of direct interaction, which result in the rapid loss of mass, energy, and angular momentum. Though crucial to understanding the fates of these systems, including their potential as gravitational wave sources, this short-lived phase is poorly understood and has thus far been unambiguously observed in only a single event, V1309 Sco. Here we show that the complex and previously unexplained photometric behavior of V1309 Sco prior to its main outburst results naturally from the runaway loss of mass and angular momentum from the outer Lagrange point, which lasts for thousands of orbits prior to the final dynamical coalescence, much longer than predicted by contemporary models. This process enshrouds the binary in a “death spiral” outflow, which affects the amplitude and phase modulation of its light curve, and contributes to driving the system together. The total amount of mass lost during this gradual phase (

) rivals the mass lost during the subsequent dynamical interaction phase, which has been the main focus of “common envelope” modeling so far. Analogous features in related transients suggest that this behavior is ubiquitous.
L’anticipation du prédicat dans l’argument externe
Authors: Cadiot Pierre
Published: November 2017

Résumé Notre objectif est de montrer certaines difficultés inhérentes à la notion de prédicat sémantique dans sa corrélation avec un argument externe. On présente successivement la question des requalifications du rôle « sujet » (ou argument externe), l’opposition prédicativité forte vs prédicativité faible, le conflit entre référence présupposée et fond thématique, puis des éléments d’approfondissement de l’opposition jugement thétique / jugement catégorique.
Phrase nominale, « parties du discours » et théorie syntaxique
Authors: de Carvalho Paulo
Published: November 2017

Résumé On défend ici, avec des arguments et des développements théoriques nouveaux, une position tenue depuis plus de 20 ans, qui consiste à affirmer, contre une tradition encore solidement ancrée, que la phrase dite « canonique », engendrée, dans les langues indo-européennes occidentales modernes, et singulièrement en français, par instanciation d’un vocable verbal, ne recouvre pas, loin s’en faut, tout le champ de la syntaxe : il y a urgence à reconnaître l’existence d’un « cas premier », ou « primaire », de phrase, qu’il faut bien appeler « nominale », plutôt qu’« averbale ». On la définira comme une « phrase-prédicat », engendrée par l’apport, à un support pré-linguistique, d’une expression nominale, identifiante ou qualifiante, et en elle-même plus ou moins complexe. De cette référence, qui lui est consubstantielle, au « présent locutif », ou « énonciatif » – à distinguer du présent « délocuté » – la phrase nominale tire son apport significatif spécifique : ce n’est pas du monde, et de ce qui (s’) y passe, qu’elle parle, mais, plutôt, de l’instant locutif lui-même, et, en fin de compte, de « moi hic et nunc  », qui instaure celui-ci. La démonstration passera par une reformulation, en termes de « personne » (invariable vs variable), de l’opposition NOM vs VERBE.
La constitución fiduciaria de la libertad política. (Por qué son importantes las coyunturas interpretativas en la filosofía política)
Authors: Mundó Jordi
Published: November 2017

Algunas formulaciones de la filosofía política reciente han descuidado el carácter históricamente indexado de conceptos como libertad política, propiedad o soberanía, propiciando un uso anacrónico e impreciso de su significado. No obstante, su posición académica y social dominante informa el «sentido común» filosófico- político de nuestra época. Locke constituye un ejemplo de cómo la coyuntura interpretativa liberal, que se desplegó en el siglo XIX y se consolidó en el XX, ha oscurecido una parte de la complejidad y pluralidad de las tradiciones intelectuales y normativas que heredó. La reconstrucción de la filosofía política lockeana a partir de su concepción fiduciaria de la libertad política contribuye a hacer de nuevo visible el significado de algunas concepciones fundamentales para la teorización normativa presente.
Nietzsche y el mejoramiento humano. Reflexiones en torno a la noción de vida
Authors: García-Granero Marina
Published: November 2017

El presente trabajo expone el diálogo entre nietzsche y la escuela darwinista, destacando el contraste entre dos nociones de «vida» opuestas: vida como lucha por la supervivencia o vida como voluntad de poder. En oposición a la selección natural, que según nietzsche no favorece a los fuertes y poderosos sino a lo mediano y al «gran número», el filósofo alemán idea un proyecto de cría (Züchtung), una formación tanto fisiológica como moral que aspira a una auténtica elevación del ser humano, mediante la superación de las interpretaciones nihilistas y la transvaloración de los valores desde una perspectiva vitalista.
¿Es sostenible una ética de la inmanencia discursiva en Foucault?
Authors: Sánchez Antonio Juan Carlos
Published: November 2017

En este artículo nos proponemos exponer, a partir de los límites conceptuales encontrados a los planteamientos arqueo-genealógicos de Michel Foucault, la posibilidad de plantear, en dos momentos –arqueo-genealógico y gubernamental–, una “ética de la insubordinación reflexiva”. Es decir, una “ética de la libertad inmanente” al débil que al decir su palabra, denuncia y al denunciar cuestiona al tirano y su mundo al habar y actuar con –y por– los otros. Esta ética de la intersubjetividad planteada como una ética de la insumisión concertada, crítica y deliberada, pensamos, puede derivar de ciertas “condiciones enunciativas” encontradas en las dos últimas investigaciones concernientes al “decir veraz” o el “hablar franco” expuestos en El gobierno de sí y de los otros (1982-1983) y El coraje de la verdad (1983-1984).
José Luis Aranguren: Cervantes y el héroe interior
Authors: Panea Márquez José Manuel
Published: November 2017

La intención de este artículo es destacar la importancia de Cervantes en Aranguren. El filósofo español interpreta el pensamiento del Quijote centrándose en la relevancia del héroe y su importancia para la moral, como una referencia crítica y ejemplar en tiempos de crisis y desánimo como los de Cervantes y los nuestros.
The Role of Macrophages in the Response to TNF Inhibition in Experimental Arthritis
Authors: Huang Qi-Quan , Birkett Robert , Doyle Renee , Shi Bo , Roberts Elyssa L. , Mao Qinwen , Pope Richard M.
Published: November 2017

The reduction of synovial tissue macrophages is a reliable biomarker for clinical improvement in patients with rheumatoid arthritis (RA), and macrophages are reduced in synovial tissue shortly after initiation of TNF inhibitors. The mechanism for this initial response is unclear. These studies were performed to identify the mechanisms responsible for the initial reduction of macrophages following TNF inhibition, positing that efflux to draining lymph nodes was involved. RA synovial tissue and synovial fluid macrophages expressed CCR7, which was increased in control macrophages following incubation with TNF-α. Human TNF transgenic (hTNF-Tg) mice were treated with infliximab after development of arthritis. Ankles were harvested and examined by histology, immunohistochemistry, quantitative RT-PCR, ELISA, and flow cytometry. hTNF-Tg mice treated with infliximab demonstrated significant clinical and histologic improvement 3 d after the initiation of therapy, at which time Ly6C+ macrophages were significantly reduced in the ankles. However, no evidence was identified to support a role of macrophage efflux to draining lymph nodes following treatment with infliximab. In contrast, apoptosis of Ly6C+ macrophages in the ankles and popliteal lymph nodes, decreased migration of monocytes into the ankles, and a reduction of CCL2 were identified following the initiation of infliximab. These observations demonstrate that Ly6C+ macrophage apoptosis and decreased ingress of circulating monocytes into the joint are responsible for the initial reduction of macrophages following infliximab treatment in hTNF-Tg mice.
Evolution, reproduction and autopoiesis
Authors: Durand Francois
Published: November 2017

The term autopoiesis was coined to describe the regenerating and self-maintaining chemical systems of cells. The term has subsequently been applied to many different fields, including sociology, systems theory and information systems. This theory postulates that an autopoietic unity (cell, machine) is an organised network of processes that exists in a delimited space, which produces components which in turn continuously regenerate and create the network of processes that produced them. The Santiago Theory of Cognition grew from the Theory of Allopoiesis stating that all living systems are cognitive systems, and the process of living is a process of cognition. Cognition is the ability to adapt to a certain environment and cognition emerges because of a continuous bilateral interaction between the system and its environment. The resultant complexity seen in living systems is caused by this interaction between the system and its environment. Autopoiesis and cognition are however opposing concepts because cognition can only exist when the system is open and not closed as autopoiesis suggests. It is also difficult to see how autopoietic systems could originate if they are closed and how the continuous change which we see in evolution can be explained if life consists of autopoietic systems. It is postulated that cells and organisms are in fact open systems relating genetically to ancestors before them and their ever-changing descendants after them and the flow of molecules and energy through an ever-changing ecology.
Extensive reading in a tertiary reading programme: Students’ accounts of affective and cognitive benefits
Authors: Boakye Naomi A.
Published: November 2017

This article reports on the extensive reading (ER) component of a reading intervention programme to improve first-year students’ reading proficiency. To make the intervention more practical and to accelerate improvement, an ER component was included in the programme. Two groups of first-year students (high-risk and low-risk) were required to read short stories and novels of their choice and to record their affective and cognitive experiences during the reading to submit as a portfolio. In addition, students answered pre- and post-intervention questionnaires on their reading habits. Students were selected based on their performance in a reading test and interviewed to gain more insight into their reading experiences. The questionnaires were analysed using the t-test, and the interview responses were analysed by content analysis. The findings show that students had benefited from ER. Questionnaire results show that students’ reading habits had improved significantly. The reports from the interviews and inventories show that students’ affective and cognitive reading levels, including reading speed, had also improved. Students also reported on the transfer of reading strategies from their ER to their academic reading. Based on the findings, recommendations are made for reading programmes at the tertiary level, specifically at this institution, to include ER in order to complement explicit teaching, instil motivation and accelerate the improvement of students’ reading proficiency.
Teachers’ perceptions of reading instruction in selected primary schools in the Eastern Cape
Authors: Cekiso Madoda
Published: November 2017

Background: There is a general outcry that too many South African Foundation Phase (Grades 1–3) teachers do not know how to teach reading and are currently teaching reading in an ad hoc, unsystematic way.Objectives: In response to this, this study explored the Foundation Phase teachers’ perceptions of their role in teaching reading. The focus was on the relevance of the initial training, awareness of reading strategies and how these strategies were reflected in their classroom practice.Method: The study was qualitative in nature and a case study design was followed. Semi-structured interviews were conducted with nine teachers who were purposively selected from three public schools. Content analysis was used to analyse the data.Results: Regarding the initial training programme, teachers received at tertiary institutions, the findings of the study showed that the majority of teachers were not adequately prepared to teach reading and to deal with learners who experience problems in reading. Some teachers indicated that they were not even trained to teach in the Foundation Phase. The findings also showed that the majority of respondents doubted if their classroom practice would yield positive results as far as reading instruction is concerned. The findings further indicated that the majority of respondents only paid attention to oral reading (observing punctuation marks and pronunciation), without attending to reading comprehension. There was a general consensus that the new ways of teaching reading were necessary in order to improve the reading ability of learners.Conclusion: Recommendations based on the findings are that institutions of higher learning that train Foundation Phase teachers should do so in ways that adequately equip them to produce student teachers who are knowledgeable about research and theory regarding how individuals learn to read. Workshops on appropriate instruction of reading strategies are recommended for in-service teachers.
Shifting boundaries of racial space in post-apartheid South Africa: The case of Afrikaner youth in East London
Authors: Ntombana Luvuyo , Bubulu Thandiwe
Published: November 2017

South African democracy has brought about changes like freedom of associations, as opposed to apartheid which emphasised separateness of races and cultures. This social change warrants new ways of living among South Africans, especially among young people. Using a qualitative approach with semi-structured interviews, this study examined how white Afrikaans-speaking university students carve out their identities, given the reality that political, social and cultural circumstances have changed in the last two decades. Participants consisted of Afrikaner university students, based in East London. This study attempts to understand difficulties and privileges associated with being a young white South African 20 years after the fall of the apartheid regime. Seeing that the participants were not born during apartheid, we wanted to understand the extent to which their parents’ perception, influence and stories affected the way participants identify themselves, their place and their roles in the democratic South Africa. The study found that Afrikaner youth are caught between two worlds: the democratic and contemporary social context, and their parents’ traditional or orthodox way of seeing things. This study also found out that, in spite of some of their parents’ influence on racism and the perception of the South African community about white people, these young people are able to carve out their own identity in which they are able to shift racial space boundaries.
Social identities and racial integration in historically white universities: A literature review of the experiences of black students
Authors: Bazana Sandiso , Mogotsi Opelo P.
Published: November 2017

South African government has been promulgating pieces of legislation aimed at ensuring racial integration, especially in higher education, and indirectly enforcing acculturation in historically white universities. Studies have proven that institutional cultures in historically white universities alienate and exclude black students’ identities. These students’ sense of social identity, which includes culture, heritage, language and traditions, and consequently self-esteem and self-concept, is altered in these institutions. Research has been scant regarding the shape and form that black students’ identity assumes when they get to these spaces. Using Tajfel and Turner’s (1979) social identity theory and Berry’s (2005) theory of acculturation, this article explores the experiences of black students in negotiating their social identities in historically white universities. Evoking Steve Biko’s analysis of ‘artificial integration’ (1986), we hope to illustrate how the ‘integration’ narrative sought to discard the identity of black students and psychologically enforce a simulation of black students into white-established identities. The study has implications for policy development as we hope to sensitise theoretically the historically white universities to, apart from mere opening of spaces of learning, understand the social identity challenges of black students in these institutions.
On the asymptotic behaviour of the kernel of an adjoint convection-diffusion operator in a long cylinder
Authors: Allaire Grégoire , Piatnitski Andrey
Published: November 2017

This paper studies the asymptotic behaviour of the principal eigenfunction of the adjoint Neumann problem for a convection diffusion operator defined in a long cylinder. The operator coefficients are 1-periodic in the longitudinal variable. Depending on the sign of the so-called longitudinal drift (a weighted average of the coefficients), we prove that this principal eigenfunction is equal to the product of a specified periodic function and of an exponential, up to the addition of fast decaying boundary layer terms.
Geometry of spaces of real polynomials of degree at most $n$
Authors: Boyd Christopher , Brown Anthony
Published: November 2017

We study the geometry of the unit ball of the space of integral polynomials of degree at most

n

on a real Banach space. We prove Smul'yan type theorems for Gâteaux and Fréchet differentiability of the norm on preduals of spaces of polynomials of degree at most

n

. We show that the set of extreme points of the unit ball of the predual of the space of integral polynomials is

\big\{\pm\sum_{j=0}^n\phi^j:\phi \in E',\|\phi\|\le 1\big\}

. This contrasts greatly with the situation for homogeneous polynomials where the set of extreme points of the unit ball is the set

\{\pm\phi^n:\phi\in E',\|\phi\|=1\}

.
Bounding the integral of powered $i$-th mean curvatures
Authors: Alonso David , Hernández Cifre María A. , Martínez Fernández Antonio R.
Published: November 2017

We get estimates for the integrals of powered

i

-th mean curvatures,

1\leq i\leq n-1

, of compact and convex hypersurfaces, in terms of the quermaß integrals of the corresponding

C^2_+

convex bodies. These bounds will be obtained as consequences of a most general result for functions defined on a general probability space. From this result, similar estimates for the integrals of any convex transformation of the elementary symmetric functions of the radii of curvature of

C^2_+

convex bodies will be also proved, both, in terms of the quermaß integrals, and of the roots of their Steiner polynomials. Finally, the radial function is considered, and estimates of the corresponding integrals are obtained in terms of the dual quermaß integrals.
A new result on averaging theory for a class of discontinuous planar differential systems with applications
Authors: Itikawa Jackson , Llibre Jaume , Novaes Douglas Duarte
Published: November 2017

We develop the averaging theory at any order for computing the periodic solutions of periodic discontinuous piecewise differential system of the form

\dfrac{d r}{d \theta}=r'=\left\{\begin{array}{l} F^+(\theta,r,\epsilon) \quad \textrm{if}\quad 0\leq\theta\leq\alpha,\\ F^-(\theta,r,\epsilon) \quad \textrm{if}\quad \alpha\leq\theta\leq 2\pi,\\ \end{array}\right.

where

F^{\pm}(\theta,r,\epsilon)=\sum_{i=1}^k\epsilon^i F_i^{\pm}(\theta,r)+\epsilon^{k+1} R^{\pm}(\theta,r,\epsilon)

with

\theta \in \mathbb{S}^1

and

r\in D,

where D is an open interval of

\mathbb{R}^{+},

and

\epsilon

is a small real parameter.

Applying this theory, we provide lower bounds for the maximum number of limit cycles that bifurcate from the origin of quartic polynomial differential systems of the form

\dot{x}=-y+xp(x,y),\quad\dot{y}=x+yp(x,y),

with

p(x,y)

a polynomial of degree

3

without constant term, when they are perturbed, either inside the class of all continuous quartic polynomial differential systems, or inside the class of all discontinuous piecewise quartic polynomial differential systems with two zones separated by the straight line

y=0

.
$L^1$-Dini conditions and limiting behavior of weak type estimates for singular integrals
Authors: Ding Yong , Lai Xudong
Published: November 2017

Let

T_\Omega

be the singular integral operator with a homogeneous kernel

\Omega

. In 2006, Janakiraman showed that if

\Omega

has mean value zero on

\mathbb S^{n-1}

and satisfies the condition

(\ast)\quad \sup_{|\xi|=1}\int_{\S^{n-1}}|\Omega(\theta)-\Omega(\theta+\delta\xi)|\,d\sigma(\theta)\leq Cn\,\delta\int_{\mathbb{S}^{n-1}}|\Omega(\theta)|\,d\sigma(\theta),

where

0<\delta<{1}/{n}

, then the following limiting behavior:

(\ast\ast)\quad \lim\limits_{\lambda\to 0_+}\lambda \, m(\{x\in\mathbb R^n:|T_\Omega f(x)|>\lambda\})= \frac{1}{n}\,\|\Omega\|_{1}\|f\|_{1}

holds for

f\in L^1(\mathbb R^n)

and

f\geq 0

.

In the present paper, we prove that if we replace the condition

(\ast)

by a more general condition, the

L^1

-Dini condition, then the limiting behavior

(\ast\ast)

still holds for the singular integral

T_\Omega

. In particular, we give an example which satisfies the

L^1

-Dini condition, but does not satisfy

(\ast)

. Hence, we improve essentially Janakiraman's above result. To prove our conclusion, we show that the

L^1

-Dini conditions defined respectively via rotation and translation in

\mathbb R^n

are equivalent (see Theorem 2.5 below), which may have its own interest in the theory of the singular integrals. Moreover, similar limiting behavior for the fractional integral operator

T_{\Omega,\alpha}

with a homogeneous kernel is also established in this paper.
Complex structures of splitting type
Authors: Angella Daniele , Otal Antonio , Ugarte Luis , Villacampa Raquel
Published: November 2017

We study the six-dimensional solvmanifolds that admit complex structures of splitting type classifying the underlying solvable Lie algebras. In particular, many complex structures of this type exist on the Nakamura manifold

X

, and they allow us to construct a countable family of compact complex non-

\partial\bar{\partial}

manifolds

X_k

,

k\in\mathbb Z

, that admit a small holomorphic deformation

\{(X_{k})_{t}\}_{t\in\Delta_k}

satisfying the

\partial\bar{\partial}

-lemma for any

t\in\Delta_k

except for the central fibre. Moreover, a study of the existence of special Hermitian metrics is also carried out on six-dimensional solvmanifolds with splitting-type complex structures.
Various approaches for the study of the complexity of some families of pseudorandom subsets
Authors: Dartyge Cécile , Gómez-Pérez Domingo
Published: November 2017

Studying randomness in different structures is important from the development of applications and theory. Dartyge, Mosaki and Sárközy (among others) have studied measures of randomness for families of subsets of integers. In this article, we improve results on the complexity of some families defined by polynomials, introducing new techniques from areas such as combinatorial geometry, geometry of numbers and additive combinatorics.
Strictly convex corners scatter
Authors: Päivärinta Lassi , Salo Mikko , Vesalainen Esa V.
Published: November 2017

We prove the absence of non-scattering energies for potentials in the plane having a corner of angle smaller than

\pi

. This extends the earlier result of Blåsten, Päivärinta and Sylvester who considered rectangular corners. In three dimensions, we prove a similar result for any potential with a circular conic corner whose opening angle is outside a countable subset of (0,

\pi

).
On the parabolic Lipschitz approximation of parabolic uniform rectifiable sets
Authors: Nyström Kaj , Strömqvist Martin
Published: November 2017

We prove the existence of big pieces of regular parabolic Lipschitz graphs for a class of parabolic uniform rectifiable sets satisfying what we call a synchronized two cube condition. An application to the fine properties of parabolic measure is given.
Polynomials of degree 4 defining units
Authors: Broche Osnel , del Río Ángel
Published: November 2017

If

x

is the generator of a cyclic group of order

n

then every element of the group ring

\mathbb Z \langle x \rangle

is the result of evaluating

x

at a polynomial of degree smaller than

n

with integral coefficients. When such an evaluation result into a unit we say that the polynomial defines a unit on order

n

. Marciniak and Sehgal have classified the polynomials of degree at most 3 defining units. The number of such polynomials is finite. However the number of polynomials of degree 4 defining units on order 5 is infinite and we give the full list of such polynomials. We prove that (up to a sign) every irreducible polynomial of degree 4 defining a unit on an order greater than 5 is of the form

a(X^4+1)+b(X^3+X)+(1-2a-2b)X^2

and obtain conditions for a polynomial of this form to define a unit. As an application we prove that if

n

is greater than 5 then the number of polynomials of degree 4 defining units on order

n

is finite and for

n\le 10

we give explicitly all the polynomials of degree 4 defining units on order

n

. We also include a conjecture on what we expect to be the full list of polynomials of degree 4 defining units, which is based on computer aided calculations.
Traitement des avulsions du plexus brachial chez le chien par réimplantation radiculaire. Etude expérimentale
Authors: Moissonnier Pierre , Lavieille Stéphane , Duchossoy Yann , Reviron Thierry , Horvat Jean-claude
Published: November 2017

Une étude expérimentale prospective a été réalisée afin de connaître les capacités de repousse axonale de neurones médulaires du chien au sein de racines du plexus brachial avulsées puis réimplantées. Les racines C6 et ZI furent avulsées et réimplantées chez 6 chiens (groupe 1) ou sectionnées après la même procédure chirurgicale (groupe témoins 2). La repousse axonale fut évaluée par marquage rétrograde à la peroxydase du raifort (HRP) et par une étude électrophysiologique. La récupération fonctionnelle a été appréciée par l’examen neurologique et par pesée comparative des muscles soumis à la réservation en comparaison avec un groupe de 12 chiens normaux. Des neurones marqués ont pu être mis en évidence chez les chiens lu groupe 1 dans la corne ventrale de la moelle épinière a proximité des acines réimplantées. La reconstitution d’unités motrices a pu être objectivée >ar électromyographie dans ce même groupe. Dans le groupe 2, on observait aucun neurone marqué à la HRP, aucune unité motrice, et l’amyotrophie était beaucoup plus sévère. Aucune récupération fonctionnelle n’a pu être ) observée dans les deux groupes. Nos résultats démontrent que la réimplantation radiculaire engendre une réinnervation chez le chien. En conclusion, nous considérons que la réimplantation radiculaire est un traitement potentiel des avulsions du plexus brachial chez le chien.
Déterminisme génétique des aptitudes au travail chez le chien et perspectives pour la sélection de l’espèce
Authors: Courreau Jean-François
Published: November 2017

L’état des connaissances sur le déterminisme génétique des aptitudes au travail chez le chien ne permet plus de doute sur sa réalité. Par contre, les détails de ce déterminisme restent mal connus. L’approche actuelle par la génétique quantitative est susceptible d’apporter une certaine lumière, notamment dans le domaine des influences respectives du patrimoine génétique et de l’environnement, manifestement très différentes selon les caractères. La connaissance du travail effectué par les chiens est indispensable au chercheur pour réaliser un bon modèle de la performance, susceptible ensuite d’être analysé par le calcul statistique. Cependant, le chercheur ne doit pas être isolé des milieux cynophiles, bénéficiaires, s’ils le désirent, du résultat des travaux. Si ceux-ci adhèrent à la nouvelle aide à la sélection qui leur est proposé, ils devront cependant collaborer en faisant évoluer l’organisation des épreuves de travail et la gestion des résultats qui en découlent.
Histoire de la médecine vétérinaire romaine et dans l’antiquité tardive. I. Les sources
Authors: Bourdy Franck
Published: November 2017

La médecine vétérinaire de l’Antiquité romaine et de l’Antiquité tardive a pour principal intérêt pour l’historien de présenter de nombreuses sources en latin et en grec. Ces sources se divisent en deux grandes catégories : traités d’agriculture où la médecine vétérinaire ne représente qu’une très petite partie, et traités de médecine vétérinaire. Le but de cet article est de dresser un état des différentes sources existantes et il mentionne pour chacune des indications sur l’auteur, une édition de référence et une traduction en français, ainsi que la place accordée à la médecine vétérinaire.
Considérations statistiques sur la qualité microbiologique en restauration collective sociale
Authors: Leprêtre Alain , Catsaras Marc
Published: November 2017

La méthode d’analyse NORECOIN (normalisée, répétitive, codée et intégrée) a été appliquée de 1985 à 1996 à un grand échantillon de restaurants de la restauration collective sociale. Au début de cette série chronologique, les notes ont fortement augmenté, tendant vers le maximum possible et traduisant donc un effort important des professionnels. Au début des années 90, les fluctuations saisonnières de la qualité sont faibles, mais un relâchement des performances est perceptible à partir de 92-93, en particulier dans les cas des restaurants livrés par traiteurs.
Trypanosoma cruzi Infection Induces Pannexin-1 Channel Opening in Cardiac Myocytes
Authors: Barría Iván , Güiza Juan , Cifuentes Fredi , Zamorano Pedro , Sáez Juan C. , González Jorge , Vega José L.
Published: November 2017

Trypanosoma cruzi, the etiological agent of Chagas diseases, invades the cardiac tissue causing acute myocarditis and heart electrical disturbances. In T. cruzi invasion, the parasite induces [Ca2+]i transients in the host cells, an essential phenomenon for invasion. To date, knowledge on the mechanism that elicits transients of [Ca2+]i during the infection of cardiac myocytes has not been fully characterized. Pannexin1 (Panx1) channel are poorly selective channels found in all vertebrates that serve as a pathway for ATP release. In this article, we demonstrate that T. cruzi infection results in the opening of Panx1 channels in cardiac myocytes. We show that pharmacological blockade of Panx1 channels inhibits T. cruzi–induced [Ca2+]i transients and invasion in cardiac myocytes. Our results indicate that opening of Panx1 channels are required for T. cruzi invasion in cardiac myocytes, and we propose that targeting Panx1 channel could provide new potential therapeutic approaches to treat Chagas disease.
Acute Q Fever Case Detection among Acute Febrile Illness Patients, Thailand, 2002–2005
Authors: Greiner Ashley L. , Bhengsri Saithip , Million Matthieu , Edouard Sophie , Thamthitiwat Somsak , Clarke Kevin , Kersh Gilbert J. , Gregory Christopher J. , Raoult Didier , Parola Philippe
Published: November 2017

Acute Q fever cases were identified from a hospital-based acute febrile illness study conducted in six community hospitals in rural north and northeast Thailand from 2002 to 2005. Of 1,784 participants that underwent Coxiella burnetii testing, nine (0.5%) participants were identified in this case-series as acute Q fever cases. Eight case-patients were located in one province. Four case-patients were hospitalized. Median age was 13 years (range: 7–69); five were male. The proportion of children with acute Q fever infection was similar to adults (P = 0.17). This previously unrecognized at-risk group, school-age children, indicates that future studies and prevention interventions should target this population. The heterogeneity of disease burden across Thailand and milder clinical presentations found in this case-series should be considered in future studies. As diagnosis based on serology is limited during the acute phase of the disease, other diagnostic options, such as polymerase chain reaction, should be explored to improve acute case detection.