Missing Lensed Images and the Galaxy Disk Mass in CXOCY J220132.8-320144

The CXOCY J220132.8-320144 system consists of an edge-on spiral galaxy lensing a background quasar into two bright images. Previous efforts to constrain the mass distribution in the galaxy have suggested that at least one additional image must be present (Castander et al. 2006). These extra images may be hidden behind the disk which features a prominent dust lane. We present and analyze Hubble Space Telescope (HST) observations of the system. We do not detect any extra images, but the observations further narrow the observable parameters of the lens system. We explore a range of models to describe the mass distribution in the system and find that a variety of acceptable model fits exist. All plausible models require 2 magnitudes of dust extinction in order to obscure extra images from detection, and some models may require an offset between the center of the galaxy and the center of the dark matter halo of 1 kiloparsec. Currently unobserved images will be detectable by future James Webb Space Telescope (JWST) observations and will provide strict constraints on the fraction of mass in the disk.Comment: 10 pages, 8 figures, 6 tables. Minor changes, version accepted for publication in Ap

Fazendo consciência à medida que passamos pelo nevoeiro: As metáforas dos diretores dentro de uma implementação da reforma nacional

Principals’ implementation of national reforms in the educational arena resembles a wild ride on a roller coaster as they face with contradicting demands, ongoing confusion and ambiguity. As critical change agents, principals interpret and translate reform demands into local practices through a process of sense-making. This current qualitative research explored 60 high school principals' sense-making processing of their leadership within a national reform through their use of metaphors. Data analysis yielded four themes: (a) reframing the principal’s role and pedagogical autonomy; (b) reframing the principal’s work; (c) reframing the school culture; and (d) reframing the principal’s relationships with teachers. This study expands the currently limited knowledge about principals' experience with and responses to reforms, and suggests implications and further research on metaphors principals use within reform implementation.La implementación de las reformas nacionales en el ámbito educativo por parte de los directores se asemeja a un paseo salvaje en una montaña rusa al enfrentarse con exigencias contradictorias, que van desde la confusión hasta la ambigüedad. Como agentes de cambio críticos, los directores interpretan y traducen las exigencias de la reforma en prácticas locales a través de un proceso de “generar conciencia”. Esta investigación en términos cualitativos exploró 60 procesos de “generación de conciencia” de los Directores de escuelas secundarias, referente a su liderazgo dentro de una reforma nacional a través del uso de metáforas. El análisis de los datos obtenidosarrojo cuatro temas: (a) replantear el papel del director y la autonomía pedagógica; (b) replantear el trabajo del director; (c) replantear la cultura escolar; y (d) replantear las relaciones del director con los maestros. Este estudio amplía el conocimiento actualmente limitado sobre la experiencia de los directores y las respuestas a las reformas, y sugiere implicaciones e incrementar la investigación sobre las metáforas que los Directores usan en la implementación de la reforma.A implementação de reformas nacionais no campo educacional pelos diretores é semelhante a um passeio selvagem em uma montanha-russa diante de demandas contraditórias, que vão desde a confusão até a ambiguidade. Como agentes de mudança crítica, os diretores interpretam e traduzem as demandas de reforma nas práticas locais através de um processo de “gerar consciência.” .Esta pesquisa, em termos qualitativos, explorou 60 processos de “geração de conscientização” dos diretores das escolas secundárias, referentes à sua liderança dentro de uma reforma nacional através do uso de metáforas. A análise dos dados obtidos revela quatro temas: (a) repensar o papel do diretor e a autonomia pedagógica; (b) repensar o trabalho do diretor; (c) repensar a cultura escolar; e (d) repensar as relações do diretor com professores. Este estudo expande o conhecimento atualmente limitado sobre a experiência dos diretores e as respostas às reformas e sugere implicações e aumenta a pesquisa sobre as metáforas que os diretores usam na implementação da reforma

HE 0047-1756: A new gravitationally lensed double QSO

The quasar HE 0047-1756, at z=1.67, is found to be split into two images 1.44" apart by an intervening galaxy acting as a gravitational lens. The flux ratio for the two components is roughly 3.5:1, depending slightly upon wavelength. The lensing galaxy is seen on images obtained at 800 nm and 2.1 \mu; there is also a nearby faint object which may be responsible for some shear. The spectra of the two quasar images are nearly identical, but the emission line ratio between the two components scale differently from the continuum. Moreover, the fainter component has a bluer continuum slope than the brighter one. We argue that these small differences are probably due to microlensing. There are hints of an Einstein ring emanating from the brighter image toward the fainter one.Comment: 4 pages, submitted to A&A Letter

Sign-changing critical points via Sandwich Pair theorems

The Sandwich Pair theorems have presented very efficient ways to determine the existence of critical points or critical sequences for nonlinear differentiable functionals. In this paper, under rather weak hypotheses new relationships are established between sign-changing critical points and Sandwich Pairs or Linking Sandwich Pairs. The abstract results are demonstrated by applications on semi-linear elliptic equations. © 2013 Elsevier Ltd. All rights reserved

Generating dynamic higher-order Markov models in web usage mining

Markov models have been widely used for modelling users’ web navigation behaviour. In previous work we have presented a dynamic clustering-based Markov model that accurately represents second-order transition probabilities given by a collection of navigation sessions. Herein, we propose a generalisation of the method that takes into account higher-order conditional probabilities. The method makes use of the state cloning concept together with a clustering technique to separate the navigation paths that reveal differences in the conditional probabilities. We report on experiments conducted with three real world data sets. The results show that some pages require a long history to understand the users choice of link, while others require only a short history. We also show that the number of additional states induced by the method can be controlled through a probability threshold parameter

Gravitational Nanolensing from Subsolar Mass Dark Matter Halos

We investigate the feasibility of extracting the gravitational nanolensing signal due to the presence of subsolar mass halos within galaxy-sized dark matter halos. We show that subsolar mass halos in a lensing galaxy can cause strong nanolensing events with shorter durations and smaller amplitudes than microlensing events caused by stars. We develop techniques that can be used in future surveys such as Pan-STARRS, LSST and OMEGA to search for the nanolensing signal from subsolar mass halos.Comment: 12 pages, 10 figures. Replaced with version accepted for publication in ApJ. Very minor changes from version

Inhibition of 4-aminobutyrate aminotransferase protects against injury-induced osteoarthritis in mice

Recently we demonstrated that ablation of the DNA methyltransferase enzyme, Dnmt3b, resulted in catabolism and progression of osteoarthritis (OA) in murine articular cartilage through a mechanism involving increased mitochondrial respiration. In this study, we identify 4-aminobutyrate aminotransferase (Abat) as a downstream target of Dnmt3b. Abat is an enzyme that metabolizes γ-aminobutyric acid to succinate, a key intermediate in the tricarboxylic acid cycle. We show that Dnmt3b binds to the Abat promoter, increases methylation of a conserved CpG sequence just upstream of the transcriptional start site, and inhibits Abat expression. Dnmt3b deletion in articular chondrocytes results in reduced methylation of the CpG sequence in the Abat promoter, which subsequently increases expression of Abat. Increased Abat expression in chondrocytes leads to enhanced mitochondrial respiration and elevated expression of catabolic genes. Overexpression of Abat in murine knee joints via lentiviral injection results in accelerated cartilage degradation following surgical induction of OA. In contrast, lentiviral-based knockdown of Abat attenuates the expression of IL-1β-induced catabolic genes in primary murine articular chondrocytes in vitro and also protects against murine articular cartilage degradation in vivo. Strikingly, treatment with the FDA-approved small-molecule Abat inhibitor, vigabatrin, significantly prevents the development of injury-induced OA in mice. In summary, these studies establish Abat as an important new target for therapies to prevent OA

Cosmon as the Modulon: Non-Gaussianity from Dark Energy

In this paper, we show that the idea of growing neutrino can result in a modulated reheating effect and produce detectable non-Gaussianity in the model where the Higgs triplet from type II seesaw mechanism plays the role of the inflaton in chaotic inflation.Comment: 6 pages, 1 figure; references added, accepted for publication in PL

Admixture of quasi-Dirac and Majorana neutrinos with tri-bimaximal mixing

We propose a realization of the so-called bimodal/schizophrenic model proposed recently. We assume S4, the permutation group of four objects as flavor symmetry giving tri-bimaximal lepton mixing at leading order. In these models the second massive neutrino state is assumed quasi-Dirac and the remaining neutrinos are Majorana states. In the case of inverse mass hierarchy, the lower bound on the neutrinoless double beta decay parameter m_ee is about two times that of the usual lower bound, within the range of sensitivity of the next generation of experiments.Comment: 8 pages, minor changes to match version accepted in PL