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Développement d’une méthode de simulation multi-échelle pour l’étude des grandes transformations dans les protéines

Dupuis, Lilianne
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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Les protéines accomplissent leur fonction dans la cellule grâce à leur faculté de changer de forme. Chaque classe de protéines peut se caractériser par une structure spécia- lisée partagée par ses membres avec un certain degré de variabilité. Tel est le cas des protéines à motifs mains-EF, qui se transforment en liant et déliant l ’ion calcium. Ce motif permet à la Troponin C de s’ouvrir et se refermer afin de moduler le mécanisme de contraction des fibres musculaires. Un mécanisme similaire permet à la Calmoduline de gérer l’activité de divers canaux cellulaires. Les techniques de simulations numériques peuvent aider à comprendre les trajectoires de ces transformations. Le projet principal de cette thèse consistait à développer une méthode informatique multi-échelle permettant de simuler des mouvements complexes à l’intérieur d ’une protéine. La représentation multi-échelle développée peut changer et s’adapter en cours de simulation. La méthode, ART holographique, explore l’espace en générant des basculements d’ensembles atomiques, selon des champs de force atomistiques non biaisés indiquant à tout moment comment les ensembles doivent pivoter. La méthode réduit le calcul des fluctuations locales mais conserve une représentation spatiale complète. La représentation multi-échelle est combinée à une technique de recherche de passages de transition énergétiquement favorables...

Traducción y validación de la versión española de la Échelle de Satisfacción des Besoins Psychologiques en el contexto educativo; Translation and validation of the Spanish version of the Échelle de Satisfaction des Besoins Psychologiques in academic context

León, Jaime; Domínguez, Evelia; Núñez, Juan L.; Pérez, Araceli; Martín Albo, José
Fonte: Murcia : Servicio de Publicaciones de la Universidad de Murcia Publicador: Murcia : Servicio de Publicaciones de la Universidad de Murcia
Tipo: Artigo de Revista Científica Formato: application/pdf
SPA
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El propósito de esta investigación fue traducir y analizar las propiedades psicométricas de la versión española de la Échelle de Satisfaction des Besoins Psychologiques en una muestra de 324 estudiantes universitarios (99 hombres y 225 mujeres). Los resultados del análisis factorial confirmatorio confirmaron la estructura de tres factores correlacionados de la escala. Asimismo, la consistencia interna mostró evidencias de fiabilidad. Se obtuvieron evidencias de validez concurrente mediante un análisis de ecuaciones estructurales en el que el clima motivacional a la tarea predecía de forma positiva las tres necesidades psicológicas básicas y éstas, a su vez, la motivación intrínseca. Los resultados apoyan preliminarmente el uso de la versión española de la escala en el contexto de la educación superior.

Développement d'une échelle de mesure de la souffrance chez les adolescents ayant le cancer

Khadra, Christelle
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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La complexité du traitement oncologique a amélioré les taux de survie des adolescents ayant le cancer mais a également augmenté leur souffrance. Le but de la présente étude était d'élaborer une échelle pour mesurer la souffrance chez cette population. À partir d’entrevues semi-structurées auprès de 19 adolescents et 16 experts, un pool d’items associés à la souffrance a été créé. Les items ont été présentés à un panel de neuf experts pour déterminer leur validité de contenu. Les analyses ont montré une validité de contenu élevée de l’échelle par l’indice de validité de contenu de 0,98 associé à un accord inter-juges de 0,88. La majorité des items étaient considérés faciles à comprendre et à y répondre. L’Échelle de Souffrance des Adolescents ayant le cancer (ESAC) est de type likert à quatre choix de réponses. Elle comprend 41 items portant sur la souffrance physique, psychologique, sociale, spirituelle, cognitive et globale.; The complexity of cancer treatment has improved the survival rates among adolescents with cancer but has also increased their suffering. The purpose of this study was to develop a scale to measure suffering in this population. A pool of items associated with suffering was created after analysing the verbatim of semi-structured interviews conducted with 19 patients and 16 experts. The items were then presented to nine experts to determine their content validity. The analysis showed a high content validity of the scale with a content validity index (CVI) of 0.98 associated with an interrater agreement (IRA) of 0.88. The majority of the items were considered easy to understand and answer. The scale...

Développement de papier bioactif par couchage à grande échelle d’enzymes immobilisées par microencapsulation

Guerrero Palacios, Marco Polo
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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L’objectif principal de cette recherche est de contribuer au développement de biocapteurs commerciaux utilisant des surfaces de papier comme matrices d’immobilisation, capables de produire un signal colorimétrique perceptible dans les limites sensorielles humaines. Ce type de biocapteur, appelé papier bioactif, pourrait servir par exemple à la détection de substances toxiques ou d’organismes pathogènes. Pour atteindre l’objectif énoncé, ce travail propose l’utilisation de systèmes enzymatiques microencapsulés couchés sur papier. Les enzymes sont des catalyseurs biologiques dotés d’une haute sélectivité, et capables d'accélérer la vitesse de certaines réactions chimiques spécifiques jusqu’à des millions des fois. Les enzymes sont toutefois des substances très sensibles qui perdent facilement leur fonctionnalité, raison pour laquelle il faut les protéger des conditions qui peuvent les endommager. La microencapsulation est une technique qui permet de protéger les enzymes sans les isoler totalement de leur environnement. Elle consiste à emprisonner les enzymes dans une sphère poreuse de taille micrométrique, faite de polymère, qui empêche l’enzyme de s’echapper, mais qui permet la diffusion de substrats à l'intérieur. La microencapsulation utilisée est réalisée à partir d’une émulsion contenant un polymère dissous dans une phase aqueuse avec l’enzyme désirée. Un agent réticulant est ensuite ajouté pour provoquer la formation d'un réseau polymérique à la paroi des gouttelettes d'eau dans l'émulsion. Le polymère ainsi réticulé se solidifie en enfermant l’enzyme à l'intérieur de la capsule. Par la suite...

Le caractère adéquat du contenu de l'échelle de mesure de la conscience de l'environnement d'affaires

Lessard, Christophe
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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Le présent travail se penche sur le concept de la conscience de l’environnement d’affaires. Ce concept fait référence à l’importance de la prise en compte par l’employé non-cadre d’un ensemble varié d’éléments d’information composant l’environnement d’affaires. La prise en considération de ces éléments d’information par l’employé aiderait ce dernier non seulement à prendre de meilleures décisions d’affaires, mais aussi à résoudre des problèmes dans un milieu de travail prônant la gestion participative. Seulement deux mémoires et un article scientifique se sont penchés sur la conscience de l’environnement d’affaires. Le mémoire d’Ève St-Onge (2007) a justifié l’existence du concept et a établi une première liste d’indicateurs reflétant les éléments d’information de l’environnement d’affaires. Pour sa part le mémoire de Véronique Gauvreau-Jean (2008) s’est plutôt attardé à la validation initiale d’une échelle de mesure de la conscience de l’environnement d’affaires. À ces deux mémoires s’ajoute l’article scientifique de Haines, Rousseau, Brotheridge et St-Onge (2012) lequel a permis de définir un ensemble d’indicateurs et de dimensions de la conscience de l’environnement d’affaires. Le présent mémoire a pour objectif de vérifier le caractère adéquat du contenu de l’échelle de Véronique Gauvreau-Jean (2008)...

Construction d'une échelle décrivant les niveaux de compétence de collaboration, à partir d'indicateurs validés par des enseignants cliniciens en médecine

Saint-Martin, Monique
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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La collaboration est une compétence essentielle que les futurs médecins doivent développer. La détermination des niveaux de compétence est cruciale dans la planification de cet apprentissage. Les échelles descriptives suscitent un intérêt croissant, car elles décrivent en termes qualitatifs les performances attendues. Nous inspirant de la méthodologie mixte de Blais, Laurier, & Rousseau (2009), nous avons construit en cinq étapes une échelle de niveau de compétence de collaboration: 1) formulation d’une liste d’indicateurs situés à quatre niveaux de la formation médicale (préclinique, externat, résidence junior et sénior) par les chercheurs (n= 3) et un groupe d’éducateurs (n=7), leaders pédagogiques possédant une expertise pour la compétence de collaboration; 2) sondage en ligne comprenant quatre questionnaires portant sur les niveaux de 118 indicateurs, auprès d’enseignants cliniciens représentant les différentes spécialités (n=277); 3) analyse, avec le modèle partial credit de Rasch, des réponses aux questionnaires appariés par calibration concurrente; 4) détermination des niveaux des indicateurs par les éducateurs et les chercheurs; et 5) rédaction de l’échelle à partir des indicateurs de chaque niveau. L’analyse itérative des réponses montre une adéquation au modèle de Rasch et répartit les indicateurs sur l’échelle linéaire aux quatre niveaux. Les éducateurs déterminent le niveau des 111 indicateurs retenus en tenant compte des résultats du sondage et de la cohérence avec le curriculum. L’échelle comporte un paragraphe descriptif par niveau...

Tradução, adaptação cultural e validação da "Edin ¿ Échelle Douleur Inconfort Nouveau-Né' para a língua portuguesa do Brasil = : Translation, cultural adaptation and validation of the "Edin - Échelle Douleur Inconfort Nouveau-Ne" into Brazilian portuguese; Translation, cultural adaptation and validation of the "Edin - Échelle Douleur Inconfort Nouveau-Ne" into Brazilian portuguese

Flávia de Souza Barbosa Dias
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/07/2012 PT
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O recém-nascido que necessita de internação em Unidade de Terapia Intensiva Neonatal é submetido a excessivos estímulos estressantes e dolorosos, intrínsecos à realização de diagnósticos e proposta terapêutica. Realizar uma avaliação acurada da dor e do desconforto do recém-nascido, afim de oferecer um tratamento adequado, é uma das dificuldades encontradas pelos profissionais de saúde que atuam em neonatologia no nosso país. Este estudo teve como objetivo desenvolver a tradução e adaptação cultural para o Brasil da escala EDIN (Échelle Douleur Inconfort Nouveau- Né), bem como realizar a validação das suas propriedades psicométricas. Este instrumento é composto por 5 indicadores de avaliação de parâmetros comportamentais e já tem sido utilizado em outros países com a finalidade de avaliar a dor e o desconforto prolongados em recém-nascidos internados em UTIN. Para o processo de tradução e adaptação cultural da escala foram seguidas as etapas recomendadas internacionalmente: a) dupla tradução para a língua portuguesa do Brasil e elaboração de uma versão síntese das traduções; b) retrotradução para a língua original; c) avaliação por comitê composto por 7 especialistas; d) pré teste. Para a validação das propriedades psicométricas foram feitas análises da confiabilidade interobservador e de consistência interna...

The chemical composition of the Galactic HII regions M8 and M17. A revision based on deep VLT echelle spectrophotometry

Peimbert, M.; Rodríguez, M.; Peimbert, A.; Ruiz González, María Teresa; Esteban, C.; García Rojas, Jorge
Fonte: Universidade do Chile Publicador: Universidade do Chile
Tipo: Artículo de revista
EN
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Publicación ISI; We present new echelle spectrophotometry of the Galactic H II regions M8 and M17. The data have been taken with the VLT UVES echelle spectrograph in the 3100 to 10400 A range. We have measured the intensities of 375 and 260 emission lines in M8 and M17 respectively, increasing significatively the number of emission lines measured in previous spectrophotometric studies of these nebulae. Most of the detected lines are permitted lines. Electron temperatures and densities have been determined using different diagnostics. We have derived He+, C++, O+ and O++ ionic abundances from pure recombination lines. We have also derived abundances from collisionally excited lines for a large number of ions of different elements. Highly consistent estimations of t(2) have been obtained by using different independent indicators; the values are moderate and very similar to those obtained in other Galactic H II regions. We report the detection of deuterium Balmer emission lines, up to DE, in M8 and show that their intensities are consistent with continuum fluorescence as their main excitation mechanism.

V1647 ORIONIS: Keck/Nirspec 2 MICRON Echelle Observations

Aspin, Colin; Greene, Tom P.; Reipurth, Bo
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/10/2008
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We present new Keck II NIRSPEC high-spectral resolution 2 um echelle observations of the young eruptive variable star V1647 Orionis. This star went into outburst in late 2003 and faded to its pre-outburst brightness after approximately 26 months. V1647 Orionis is the illuminating star of McNeil's Nebula and is located near M 78 in the Lynds 1630 dark cloud. Our spectra have a resolving power of approximately 18,000 and allow us to study in detail the weak absorption features present on the strong near-IR veiled continuum. An analysis of the echelle orders containing Mg I (2.1066 um) and Al I (2.1099 um), Br-gamma (2.1661 um), the Na I doublet (2.206 and 2.209 um), and the CO overtone bandhead (2.2935 um) gives us considerable information on the physical and geometric characteristics of the regions producing these spectral features. We find that, at high-spectral resolution, V1647 Orionis in quiescence resembles a significant number of FU Orionis type eruptive variables and does not appear similar to the quiescent EX Lupi variables observed. This correspondence is discussed and implications for the evolutionary state of the star are considered.; Comment: 37 pages, 3 Tables, 17 Figures

Background and Scattered Light Subtraction in the High-Resolution Echelle Modes of the Space Telescope Imaging Spectrograph

Howk, J. Christopher; Sembach, Kenneth R.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/12/1999
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We present a simple, effective approach for estimating the on-order backgrounds of spectra taken with the highest-resolution modes of the Space Telescope Imaging Spectrograph (STIS) on-board the Hubble Space Telescope. Our scheme for determining the on-order background spectrum uses polynomial fits to the inter-order scattered light visible in the two-dimensional STIS MAMA images. We present a suite of high-resolution STIS spectra to demonstrate that our background subtraction routine produces the correct overall zero point, as judged by the small residual flux levels in the centers of strongly-saturated interstellar absorption lines. Although there are multiple sources of background light in STIS echelle mode data, this simple approach works very well for wavelengths longward of Lyman-alpha. At shorter wavelengths, the smaller order separation and generally lower signal-to-noise ratios of the data can reduce the effectiveness of our background estimation procedure. Slight artifacts in the background-subtracted spectrum can be seen in some cases, particularly at wavelengths <1300 Ang. Most of these are caused by echelle scattering of strong spectral features into the inter-order light. We discuss the limitations of high-resolution STIS data in light of the uncertainties associated with our background subtraction procedure. We compare our background-subtracted STIS spectra with GHRS Ech-A observations of the DA white dwarf G191-B2B and GHRS first-order G160M observations of the early-type star HD 218915. We find no significant differences between the GHRS data and the STIS data reduced with our method in either case.; Comment: To appear in The Astronomical Journal; 37 pages...

PEPSI: The high-resolution echelle spectrograph and polarimeter for the Large Binocular Telescope

Strassmeier, K. G.; Ilyin, I.; Järvinen, A.; Weber, M.; Woche, M.; Barnes, S. I.; Bauer, S. -M.; Beckert, E.; Bittner, W.; Bredthauer, R.; Carroll, T. A.; Denker, C.; Dionies, F.; DiVarano, I.; Döscher, D.; Fechner, T.; Feuerstein, D.; Granzer, T.; Hahn
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/05/2015
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PEPSI is the bench-mounted, two-arm, fibre-fed and stabilized Potsdam Echelle Polarimetric and Spectroscopic Instrument for the 2x8.4 m Large Binocular Telescope (LBT). Three spectral resolutions of either 43 000, 120 000 or 270 000 can cover the entire optical/red wavelength range from 383 to 907 nm in three exposures. Two 10.3kx10.3k CCDs with 9-{\mu}m pixels and peak quantum efficiencies of 96 % record a total of 92 echelle orders. We introduce a new variant of a wave-guide image slicer with 3, 5, and 7 slices and peak efficiencies between 96 %. A total of six cross dispersers cover the six wavelength settings of the spectrograph, two of them always simultaneously. These are made of a VPH-grating sandwiched by two prisms. The peak efficiency of the system, including the telescope, is 15% at 650 nm, and still 11% and 10% at 390 nm and 900 nm, respectively. In combination with the 110 m2 light-collecting capability of the LBT, we expect a limiting magnitude of 20th mag in V in the low-resolution mode. The R=120 000 mode can also be used with two, dual-beam Stokes IQUV polarimeters. The 270 000-mode is made possible with the 7-slice image slicer and a 100- {\mu}m fibre through a projected sky aperture of 0.74", comparable to the median seeing of the LBT site. The 43000-mode with 12-pixel sampling per resolution element is our bad seeing or faint-object mode. Any of the three resolution modes can either be used with sky fibers for simultaneous sky exposures or with light from a stabilized Fabry-Perot etalon for ultra-precise radial velocities. CCD-image processing is performed with the dedicated data-reduction and analysis package PEPSI-S4S. A solar feed makes use of PEPSI during day time and a 500-m feed from the 1.8 m VATT can be used when the LBT is busy otherwise. In this paper...

Performance characteristics of the new Keck Observatory echelle spectrograph and imager

Sheinis, A. I.; Miller, J.; Bolte, M.; Sutin, B.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 04/10/2000
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The Echelle Spectrograph and Imager (ESI) is a multipurpose instrument which has been delivered by the Instrument Development Laboratory of Lick Observatory for use at the Cassegrain focus of the Keck II telescope. ESI saw first light on August 29, 1999. The optical performance of the instrument has been measured using artificial calibration sources and starlight. Measurements of the average image FWHM in echelle mode are 22 microns (0.22 arcseconds), 16 to 18 microns (0.16 to 0.18 arcseconds) in broad band imaging mode, and comparable in the low-dispersion prismatic mode (LDP). Images on the sky, under best seeing conditions show FWHM sizes of 34 microns (0.34 arcseconds). Maximum efficiencies are measured to be 30% for echelle and anticipated to be greater than 38% for low dispersion prismatic mode including atmospheric, telescope and detector losses. In this paper we describe the instrument and its specifications. We discuss the testing that led to the above conclusions.; Comment: 9 pages, 5 figures, replaced figures with gifs

The Interstellar Medium of GRB Host Galaxies I. Echelle Spectra of Swift GRB Afterglows

Prochaska, J. X.; Chen, H. -W.; Bloom, J. S.; Dessauges-Zavadsky, M.; O'Meara, J. M.; Foley, R. J.; Bernstein, R.; Burles, S.; Dupree, A. K.; Falco, E.; Thompson, I. B.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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We present optical echelle spectra of four gamma-ray burst (GRB) afterglows (GRB 050730, GRB 050820, GRB 051111, and GRB 060418) discovered during the first 1.5 years of operation of the Swift satellite and localized by either the Swift telescope or follow-up ground-based imaging. We analyze the spectra to derive accurate column density measurements for the transitions arising in the interstellar medium (ISM) of the GRB host galaxies. These measurements can be used to constrain the physical properties of the ISM including the metallicity, dust-to-gas ratio, ionization state, and chemical abundances of the gas. We also present measurements of the strong MgII systems in the GRB afterglow spectra. With the publication of this paper, we provide the first data release of echelle afterglow spectra by the GRAASP collaboration to the general community.; Comment: 52 pages, 18 figures. Accepted to ApJS. The spectra will be published with the paper and is also available upon request. A complete version with full-resolution figures is available at http://lambda.uchicago.edu/public/tmp/echelle.pdf

The coronal line regions of planetary nebulae NGC6302 and NGC6537: 3-13um grating and echelle spectroscopy

Casassus, Simon; Roche, Patrick F.; Barlow, Mike J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/11/1999
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We report on advances in the study of the cores of NGC6302 and NGC6537 using infrared grating and echelle spectroscopy. In NGC6302, emission lines from species spanning a large range of ionization potential, and in particular [SiIX]3.934um, are interpreted using photoionization models (including CLOUDY), which allow us to reestimate the central star's temperature to be about 250000K. All of the detected lines are consistent with this value, except for [AlV] and [AlVI]. Aluminium is found to be depleted to one hundredth of the solar abundance, which provides further evidence for some dust being mixed with the highly ionized gas (with photons harder than 154eV). A similar depletion pattern is observed in NGC6537. Echelle spectroscopy of IR coronal ions in NGC6302 reveals a stratified structure in ionization potential, which confirms photoionization to be the dominant ionization mechanism. The lines are narrow (< 22km/s FWHM), with no evidence of the broad wings found in optical lines from species with similar ionization potentials, such as [NeV]3426A. We note the absence of a hot bubble, or a wind blown bipolar cavity filled with a hot plasma, at least on 1'' and 10km/s scales. We also provide accurate new wavelengths for several of the infrared coronal lines observed with the echelle.; Comment: Accepted for publication in MNRAS

Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra

Becker, Juliette C.; Johnson, John Asher; Vanderburg, Andrew; Morton, Timothy D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/03/2015
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We present a technique to extract radial velocity measurements from echelle spectrograph observations of rapidly rotating stars ($V\sin{i} \gtrsim 50$ km s$^{-1}$). This type of measurement is difficult because the line widths of such stars are often comparable to the width of a single echelle order. To compensate for the scarcity of lines and Doppler information content, we have developed a process that forward-models the observations, fitting the radial velocity shift of the star for all echelle orders simultaneously with the echelle blaze function. We use our technique to extract radial velocity measurements from a sample of rapidly rotating A- and B-type stars used as calibrator stars observed by the California Planet Survey observations. We measure absolute radial velocities with a precision ranging from 0.5-2.0 km s$^{-1}$ per epoch for more than 100 A- and B-type stars. In our sample of 10 well-sampled stars with radial velocity scatter in excess of their measurement uncertainties, three of these are single-lined binaries with long observational baselines. From this subsample, we present detections of two previously unknown spectroscopic binaries and one known astrometric system. Our technique will be useful in measuring or placing upper limits on the masses of sub-stellar companions discovered by wide-field transit surveys...

On the interpretation of echelle diagrams for solar-like oscillations. Effect of centrifugal distortion

Suárez, J. C.; Goupil, M. J.; Reese, D. R.; Samadi, R.; Lignieres, F.; Rieutord, M.; Lochard, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/09/2010
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This work aims at determining the impact of slow to moderate rotation on the regular patterns often present in solar-like oscillation spectra. We focus on the well-known asteroseismic diagnostic echelle diagrams, examining how rotation may modify the estimates of the large and small spacings, as well as the identification of modes. We illustrate the work with a real case: the solar-like star $\eta$ Bootis. The modeling takes into account rotation effects on the equilibrium models through an effective gravity and on the oscillation frequencies through both perturbative and non-perturbative calculations. We compare the results of both type of calculations in the context of the regular spacings (like the small spacings and the scaled small spacings) and echelle diagrams. We show that for echelle diagrams the perturbative approach remains valid for rotational velocities up to 40-50 km/s. We show that for the rotational velocities measured in solar-like stars, theoretical oscillation frequencies must be corrected up to the second-order in terms of rotation rate, including near degeneracy effects. For rotational velocities of about 16 km/S and higher, diagnostics on large spacings and on modal identification through echelle diagrams can be significantly altered by the presence of the $m\neq0$ components of the rotationally split modes. We found these effects to be detectable in the observed frequency range. Analysis of the effects of rotation on small spacings and scaled small spacings reveals that these can be of the order of...

Modelling high resolution Echelle spectrographs for calibrations: Hanle Echelle spectrograph, a case study

Chanumolu, Anantha; Jones, Damien; Thirupathi, Sivarani
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/05/2015
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We present a modelling scheme that predicts the centroids of spectral line features for a high resolution Echelle spectrograph to a high accuracy. Towards this, a computing scheme is used, whereby any astronomical spectrograph can be modelled and controlled without recourse to a ray tracing program. The computations are based on paraxial ray trace and exact corrections added for certain surface types and Buchdahl aberration coefficients for complex modules. The resultant chain of paraxial ray traces and corrections for all relevant components is used to calculate the location of any spectral line on the detector under all normal operating conditions with a high degree of certainty. This will allow a semi-autonomous control using simple in-house, programming modules. The scheme is simple enough to be implemented even in a spreadsheet or in any scripting language. Such a model along with an optimization routine can represent the real time behaviour of the instrument. We present here a case study for Hanle Echelle Spectrograph. We show that our results match well with a popular commercial ray tracing software. The model is further optimized using Thorium Argon calibration lamp exposures taken during the preliminary alignment of the instrument. The model predictions matched the calibration frames at a level of 0.08 pixel. Monte Carlo simulations were performed to show the photon noise effect on the model predictions.

HIRDES - The High-Resolution Double-Echelle Spectrograph for the World Space Observatory Ultraviolet (WSO/UV)

Werner, K.; Barnstedt, J.; Gringel, W.; Kappelmann, N.; Becker-Ross, H.; Florek, S.; Graue, R.; Kampf, D.; Reutlinger, A.; Neumann, C.; Shustov, B.; Moisheev, A.; Skripunov, E.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/11/2007
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The World Space Observatory Ultraviolet (WSO/UV) is a multi-national project grown out of the needs of the astronomical community to have future access to the UV range. WSO/UV consists of a single UV telescope with a primary mirror of 1.7m diameter feeding the UV spectrometer and UV imagers. The spectrometer comprises three different spectrographs, two high-resolution echelle spectrographs (the High-Resolution Double-Echelle Spectrograph, HIRDES) and a low-dispersion long-slit instrument. Within HIRDES the 102-310nm spectral band is split to feed two echelle spectrographs covering the UV range 174-310nm and the vacuum-UV range 102-176nm with high spectral resolution (R>50,000). The technical concept is based on the heritage of two previous ORFEUS SPAS missions. The phase-B1 development activities are described in this paper considering performance aspects, design drivers, related trade-offs (mechanical concepts, material selection etc.) and a critical functional and environmental test verification approach. The current state of other WSO/UV scientific instruments (imagers) is also described.; Comment: Accepted for publication in Advances in Space Research

Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra

Becker, Juliette C.; Johnson, John Asher; Vanderburg, Andrew; Morton, Timothy D.
Fonte: American Astronomical Society Publicador: American Astronomical Society
Tipo: Article; PeerReviewed Formato: application/pdf; application/pdf
Publicado em /04/2015
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We present a technique to extract radial velocity (RV) measurements from echelle spectrograph observations of rapidly rotating stars (V sin i ≳ 50 kms^(−1)). This type of measurement is difficult because the line widths of such stars are often comparable to the width of a single echelle order. To compensate for the scarcity of lines and Doppler information content, we have developed a process that forward-models the observations, fitting the RV shift of the star for all echelle orders simultaneously with the echelle blaze function. We use our technique to extract RV measurements from a sample of rapidly rotating A- and B-type stars used as calibrator stars observed by the California Planet Survey observations. We measure absolute RVs with a precision ranging from 0.5–2.0 kms^(−1) per epoch for more than 100 A- and B-type stars. In our sample of 10 well-sampled stars with RV scatter in excess of their measurement uncertainties, three of these are single-lined binaries with long observational baselines. From this subsample, we present detections of two previously unknown spectroscopic binaries and one known astrometric system. Our technique will be useful in measuring or placing upper limits on the masses of sub-stellar companions discovered by wide-field transit surveys...

PROALFA (MG): Avaliação da alfabetização, em larga escala, no Brasil; PROALFA (MG): A large-scale evaluation of early literacy in Brazil; PROALFA (MG): Évaluation de l'alphabétisation à grande échelle au Brésil

Filgueiras, Karina Fideles
Fonte: Universidade de São Paulo. Faculdade de Educação Publicador: Universidade de São Paulo. Faculdade de Educação
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 01/03/2013 POR
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O presente artigo pretende contextualizar o Programa de Avaliação da Alfabetização do Estado de Minas Gerais – PROALFA (MG), no cenário internacional, nacional e estadual. No Brasil, várias são as avaliações em larga escala realizadas, em diferentes instâncias, que se apresentam em todos os segmentos de ensino. Porém, estas avaliações sobre a alfabetização nos estados do Espírito Santo, Ceará e Minas Gerais, diferenciam-se por ultrapassar a visão do instrumento de avaliação. Além dos instrumentos avaliativos, também são aplicados questionários contextuais para gestores, professores e alunos, na tentativa de se estabelecer o cruzamento de dados quantitativos com dados qualitativos, buscando, assim, captar as especificidades regionais e por escolas, considerando-se os seus contextos de produção do ensino-aprendizagem. O objetivo final desses tipos de avaliação em larga escala, que também podem ter caráter longitudinal, é de prevenção dos resultados poucos satisfatórios, dos alunos brasileiros, nos segmentos de ensino avaliados por programas internacionais, tais como o PISA. Há que se considerar as diferenças na produção dos indicadores, na frequência da medição, no tipo de avaliação em larga escala...