"Non, moi je lui dis pas en turc, ou en portugais, ou en, j'sais pas moi en arabe": exploring teacher ideologies in multilingual/cultural preschool contexts in France

This contribution explores the relationship between language ideologies and teaching with specific reference to the French national education context and in particular with respect to the education of children for whom French, the language of schooling, is not the language spoken in the home. The discourse of three teachers working in multilingual/cultural preschools is examined, revealing both beliefs about languages and practiced language policies underpinned by deep-rooted language ideologies which perpetuate a monolingual habitus. It is argued that in order to challenge the myths which support this monolingual mindset, it is essential to nurture teacher language awareness, underpinned by knowledge, values and a deeper understanding of the complexities of living and learning through multiple languages.Este artículo explora la relación entre ideologías lingüísticas y prácticas educativas de los maestros de preescolar en Francia, en particular maestros que trabajan con alumnos que hablan una lengua diferent que la lengua vehicular de la escuela. El análisis de discurso de tres profesores que trabajan en contextos lingüística y culturalmente heterogéneos revela que sus representaciones y sus políticas lingüísticas practicadas, son arraigadas en ideologías que perpetúan el habitus monolingüe. Con el fin de desafiar los mitos subyacentes a esta visión monolingüe del aprendizaje y de la enseñanza, hay que desarrollar la conciencia lingüística, alimentada por los conocimientos, valores y comprensión de las complejidades asociadas con el aprendizaje y la enseñanza de idiomas multilingüe.Aquest article explora la relació entre ideologies lingüístiques i pràctiques educatives dels mestres de preescolar a França, en particular mestres qui treballen amb alumnes per als que la llengua de l'escola no és l'idioma que parlen a casa. Anàlisi de discurs de tres professors que treballen en contextos lingüística i culturalment heterogenis revela que les seves representacions i les seves polítiques lingüístiques practicades, són arrelades en ideologies que perpetuen l'habitus monolingüe. Per tal de desafiar els mites subjacents a aquesta visió monolingüe d'aprenentatge i ensenyament, cal desenvolupar la consciència lingüística, alimentada pels coneixements, valors i comprensió de les complexitats associades amb l'aprenentatge i l'ensenyament d'idiomes multilingüe.Cette contribution explore la relation entre les idéologies linguistiques et les pratiques pédagogiques d'enseignants d'école maternelle en France envers les élèves pour qui la langue de l'école n'est pas la langue parlée à la maison. L'analyse de discours de trois enseignantes qui travaillent dans des contextes linguistiquement et culturellement hétérogènes, révèle des représentations ainsi que des politiques linguistiques pratiquées, ancrées dans des idéologies qui font perdurer l'habitus monolingue. Dans l'optique de remettre en question les mythes qui sous-tendent cette vision monolingue de l'apprentissage et de l'enseignement, le développement d'une conscience linguistique, nourrie par des connaissances, des valeurs et une meilleure compréhension des complexités associées à l'apprentissage et à l'enseignement en milieu multilingue, est proposé

Inhibition of vascular endothelial growth factor‐A downregulates angiogenesis in psoriasis: A pilot study

BackgroundVascular Endothelial Growth Factor (VEGF)-A-mediated angiogenesis participates in the pathogenesis of psoriasis, thus inviting the hypothesis that anti-VEGF-A therapy could be beneficial in psoriasis. While anti-angiogenic agents are used in oncology and ophthalmology, these therapeutic strategies remain unexplored for the management of psoriasis.ObjectiveOur objective was to investigate ex vivo how VEGF-A blockade impacts blood vessels, epidermis and immune cells in organ-cultured plaque and non-lesional skin from patients with psoriasis.MethodsSkin biopsies from patients with psoriasis (n = 6; plaque and non-lesional skin) and healthy controls (n = 6) were incubated with anti-VEGF-A monoclonal antibody (bevacizumab, Avastin®) or a human IgG1 isotype control for 72-h in serum-free organ culture. CD31/LYVE-1, Ki-67, and mast cell tryptase expression were assessed by quantitative immunohistomorphometry. VEGF-A levels in plasma, PBMCs and skin culture supernatants were measured.ResultsInhibition of VEGF-A blocked all free VEGF-A ex vivo, reduced blood vessel area and the number of blood vessel endothelial cells in plaques of psoriasis (*p < 0.05). The treatment effect correlated significantly with levels of VEGF-A in organ culture supernatants (r = 0.94; *p < 0.05) from plaque skin and with plasma levels of VEGF-A from patients with psoriasis (r = 0.943; *p = 0.017).ConclusionsThese ex vivo data are the first studies to objectively investigate the potential of VEGF-A inhibition as a novel adjuvant treatment strategy for psoriasis. Taken together, our data encourage further investigation by clinical trial to explore whether downregulating pathological angiogenesis has clinical utility, especially in patients with severe psoriasis or those with elevated levels of VEGF-A in plasma and/or skin

UV Spectropolarimetry of Narrow-line Radio Galaxies

We present the results of UV spectropolarimetry (2000 - 3000A) and far-UV spectroscopy (1500 - 2000A) of two low-redshift narrow-line radio galaxies (NLRGs) taken with the Faint Object Spectrograph onboard the Hubble Space Telescope (HST). Spectropolarimetry of several NLRGs has shown that, by the presence of broad permitted lines in polarized flux spectrum, they have hidden quasars seen through scattered light. Imaging polarimetry has shown that NLRGs including our targets often have large scattering regions of a few kpc to >~10 kpc scale. This has posed a problem about the nature of the scatterers in these radio galaxies. Their polarized continuum has the spectral index similar to or no bluer than that of quasars, which favors electrons as the dominant scattering particles. The large scattering region size, however, favors dust scattering, because of its higher scattering efficiency compared to electrons. In this paper, we investigate the polarized flux spectrum over a wide wavelength range, combining our UV data with previous optical/infrared polarimetry data. We infer that the scattering would be often caused by opaque dust clouds in the NLRGs and this would be a part of the reason for the apparently grey scattering. In the high-redshift radio galaxies, these opaque clouds could be the proto-galactic subunits inferred to be seen in the HST images. However, we still cannot rule out the possibility of electron scattering, which could imply the existence of a large gas mass surrounding these radio galaxies.Comment: 25 pages, 21 figures. To appear in Ap

Nanofilters for Optical Nanocircuits

We theoretically and numerically study the design of optical 'lumped' nanofiltering devices in the framework of our recently proposed paradigm for optical nanocircuits. In particular, we present the design of basic filtering elements, such as low-pass, band-pass, stop-band and high-pass 'lumped' nanofilters, for use in optical nanocircuits together with more complex designs, such as multi-zero or multi-pole nanofilters, to work at THz, infrared and optical frequencies. Following the nanocircuit theory, we show how it is possible to design such complex frequency responses by simple rules, similar to RF circuit design, and we compare the frequency response of these optical nanofilters with classic filters in RF circuits. These results may provide a theoretical foundation for fabricating nanofilters in optical lumped nanocircuit devices.Comment: 34 pages, 14 figure

Synthesis and Characterization of Single Crystal Samples of Spin-1/21/2 Kagome Lattice Antiferromagnets in the Zn-Paratacamite Family Znx_{x}Cu4−x_{4-x}(OH)6_{6}Cl2_{2}

The Zn-paratacamite family, Zn$_{x}$Cu$_{4-x}$(OH)$_{6}$Cl$_{2}$ for $x \, \geq$ 0.33, is an ideal system for studying spin-1/2 frustrated magnetism in the form of antiferromagnetic Cu$^{2+}$ kagome planes. Here we report a new synthesis method by which high quality millimeter-sized single crystals of Zn-paratacamite have been produced. These crystals have been characterized by metal analysis, x-ray diffraction, neutron diffraction, and thermodynamic measurements. The $x$ = 1 member of the series displays a magnetic susceptibility that is slightly anisotropic at high temperatures with $\chi_{c} \, > \, \chi_{ab}$. Neutron and synchrotron x-ray diffraction experiments confirm the quality of these $x$ = 1 single crystals and indicate no obvious structural transition down to temperatures of T=2 K.Comment: 4 pages, 3 figures, accepted by PRB rapid communicatio

Association between 5-HTTLPR and Borderline Personality Disorder Traits among Youth

This study provides the first genetic association examination of borderline personality disorder (BPD) traits in children and adolescents (ages 9–15) using two independent samples of youth recruited from the general community. We tested the a priori hypothesis that the serotonin transporter promoter gene (5-HTTLPR) would relate specifically to BPD traits in youth. This association was hypothesized based on prior genetic association research with BPD adults and theory positing that emotion dysregulation may be a core risk process contributing to BPD. Youth provided DNA via buccal cells. Both youth and a parent completed self-report measures assessing youth's BPD traits and depressive symptoms. Results from both Study 1 (N = 242) and an independent replication sample of Study 2 (N = 144) showed that carriers of the short allele of 5-HTTLPR exhibited the highest levels of BPD traits. This relation was observed even after controlling for the substantial co-occurrence between BPD traits and depressive symptoms. This specific association between 5-HTTLPR and BPD traits among youth supports previous genetic associations with adults diagnosed with BPD and provides preliminary support for a developmental extension of etiological risk for BPD among youth

Quantum interference and Klein tunneling in graphene heterojunctions

The observation of quantum conductance oscillations in mesoscopic systems has traditionally required the confinement of the carriers to a phase space of reduced dimensionality. While electron optics such as lensing and focusing have been demonstrated experimentally, building a collimated electron interferometer in two unconfined dimensions has remained a challenge due to the difficulty of creating electrostatic barriers that are sharp on the order of the electron wavelength. Here, we report the observation of conductance oscillations in extremely narrow graphene heterostructures where a resonant cavity is formed between two electrostatically created bipolar junctions. Analysis of the oscillations confirms that p-n junctions have a collimating effect on ballistically transmitted carriers. The phase shift observed in the conductance fringes at low magnetic fields is a signature of the perfect transmission of carriers normally incident on the junctions and thus constitutes a direct experimental observation of ``Klein Tunneling.''Comment: 13 pages and 6 figures including supplementary information. The paper has been modified in light of new theoretical results available at arXiv:0808.048

Absence of a Finite-Temperature Melting Transition in the Classical Two-Dimensional One-Component Plasma

Vortices in thin-film superconductors are often modelled as a system of particles interacting via a repulsive logarithmic potential. Arguments are presented to show that the hypothetical (Abrikosov) crystalline state for such particles is unstable at any finite temperature against proliferation of screened disclinations. The correlation length of crystalline order is predicted to grow as $\sqrt{1/T}$ as the temperature $T$ is reduced to zero, in excellent agreement with our simulations of this two-dimensional system.Comment: 3 figure

Disentangling protostellar evolutionary stages in clustered environments using Spitzer-IRS spectra and comprehensive SED modeling

When studying the evolutionary stages of protostars that form in clusters, the role of any intracluster medium cannot be neglected. High foreground extinction can lead to situations where young stellar objects (YSOs) appear to be in earlier evolutionary stages than they actually are, particularly when using simple criteria like spectral indices. To address this issue, we have assembled detailed SED characterizations of a sample of 56 Spitzer-identified candidate YSOs in the clusters NGC 2264 and IC 348. For these, we use spectra obtained with the Infrared Spectrograph onboard the Spitzer Space Telescope and ancillary multi-wavelength photometry. The primary aim is twofold: 1) to discuss the role of spectral features, particularly those due to ices and silicates, in determining a YSO's evolutionary stage, and 2) to perform comprehensive modeling of spectral energy distributions (SEDs) enhanced by the IRS data. The SEDs consist of ancillary optical-to-submillimeter multi-wavelength data as well as an accurate description of the 9.7 micron silicate feature and of the mid-infrared continuum derived from line-free parts of the IRS spectra. We find that using this approach, we can distinguish genuine protostars in the cluster from T Tauri stars masquerading as protostars due to external foreground extinction. Our results underline the importance of photometric data in the far-infrared/submillimeter wavelength range, at sufficiently high angular resolution to more accurately classify cluster members. Such observations are becoming possible now with the advent of the Herschel Space Observatory.Comment: Accepted for publication in Ap

Critical behavior of the random-anisotropy model in the strong-anisotropy limit

We investigate the nature of the critical behavior of the random-anisotropy Heisenberg model (RAM), which describes a magnetic system with random uniaxial single-site anisotropy, such as some amorphous alloys of rare earths and transition metals. In particular, we consider the strong-anisotropy limit (SRAM), in which the Hamiltonian can be rewritten as the one of an Ising spin-glass model with correlated bond disorder. We perform Monte Carlo simulations of the SRAM on simple cubic L^3 lattices, up to L=30, measuring correlation functions of the replica-replica overlap, which is the order parameter at a glass transition. The corresponding results show critical behavior and finite-size scaling. They provide evidence of a finite-temperature continuous transition with critical exponents $\eta_o=-0.24(4)$ and $\nu_o=2.4(6)$. These results are close to the corresponding estimates that have been obtained in the usual Ising spin-glass model with uncorrelated bond disorder, suggesting that the two models belong to the same universality class. We also determine the leading correction-to-scaling exponent finding $\omega = 1.0(4)$.Comment: 24 pages, 13 figs, J. Stat. Mech. in pres