2,462 research outputs found

    Eye-controlled ''teletypewriter''

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    Oculometer provides dynamic measurement of subject's look direction, and its outputs can be used to generate visual display of his look pattern and/or to cause equipment operation associated with his lookpoint at given times. Measured eye-direction information could be used as control input at man/machine interface

    Complex Velocity Fields in the Shell of T Pyxidis

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    We present spatially-resolved, moderate-resolution spectrophotometry of the recurrent nova T Pyx and a portion of the surrounding shell. The spectrum extracted from a strip of width 10'' centered on the star shows well-known, strong emission lines typical of old novae, plus a prominent, unfamiliar emission line at 6590 Angstroms. This line, and a weaker companion at 6540 Angstroms which we also detect, have been previously reported by Shahbaz et al., and attributed to Doppler-shifted H alpha emission from a collimated jet emerging from T Pyx. We demonstrate that these lines are instead due to [NII] 6548, 6584 from a complex velocity field in the surrounding nebula. The comments of past workers concerning the great strength of HeII 4686 in T Pyx itself are also reiterated.Comment: 8 pages including 2 figures; Accepted for publication in The Astrophysical Journal Letter

    The Distance to NGC 5128 (Centaurus A)

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    In this paper we review the various high precision methods that are now available to determine the distance to NGC 5128. These methods include: Cepheids, TRGB (tip of the red giant branch), PNLF (planetary nebula luminosity function), SBF (surface brightness fluctuations) and Long Period Variable (LPV) Mira stars. From an evaluation of these methods and their uncertainties, we derive a best-estimate distance of 3.8 +- 0.1 Mpc to NGC 5128 and find that this mean is now well supported by the current data. We also discuss the role of NGC 5128 more generally for the extragalactic distance scale as a testbed for the most direct possible comparison among these key methods.Comment: in press PASA; minor text change

    Hybrid-learning for social design

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    Underlying causes of conflict, inequity, and injustice remain deeply entrenched in the lives of people ranging from impoverished villages to overpopulated megalopolises. To help address these complex issues, social design brings together designers from varying disciplines to address the needs of the community. While universities across the world recognize the need to introduce social design pedagogy into their curriculum, many programs remain confined within Western post-graduate education. In response, two multidisciplinary professors initiated a team-taught \u27Design for Social Change\u27 course in an undergraduate design program in Dubai, UAE. Open to students across disciplines, the course followed a hybrid-learning approach to planning, conducting, and evaluating learning activities. The methodology empowered students to determine their project interest, cooperatively build research, and value their diverse skills. This paper introduces the notion of hybrid-learning, collabor-active team-teaching in an interdisciplinary classroom, and applies the methodology to a social design course in the MENA region. This paper has been presented as part of the Tasmeem Exploration Platform during Tasmeem Conference, Doha, 2013

    Diversidad de especies de Xanthoparmelia (Parmeliaceae) en la vegetación de matorrales xerofíticos mexicanos, evidenciada por datos moleculares, morfológicos y químicos

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    The genus Xanthoparmelia is the largest genus of lichen- forming fungi with about 800 species worldwide. Xanthoparmelia is also common in the deserts of central Mexico, but only a few molecular studies exist on its species’ diversity in this region. In this study, we sampled 38 Xanthoparmelia species from around the world including species from the xerophytic scrubs of central Mexico to assess the diversity using an integrative approach. Molecular phylogenetic analyses were performed using a combination of the ITS, mtSSU and nuLSU genetic markers. We evaluated our phylogenetic results in a context of traditional morphological and chemical characters. The combined evidence of molecular, morphological, and chemical data identified a total of 18 Xanthoparmelia species-level lineages occurring in central Mexico. However, numerous traditionally circumscribed species did not form monophyletic groups in the molecular phylogenetic reconstructions. This conflict indicates that taxonomy and species delimitation in the genus Xanthoparmelia requires revision and emphasizes the importance of molecular evidence for more robust species delimitations in this genus.Xanthoparmelia es el género más grande de hongos liquenizados, con alrededor de 800 especies en todo el mundo. Xanthoparmelia es común en los desiertos del centro de México, pero existen pocos estudios moleculares sobre la diversidad de especies en esta región. En este estudio, muestreamos 38 especies de Xanthoparmelia de diferentes partes del mundo, incluidas especies de los matorrales xerófilos del centro de México, para evaluar la diversidad usando una aproximación integrativa. Los análisis filogenéticos moleculares se realizaron combinando los marcadores genéticos ITS, mtSSU y nuLSU. Además, evaluamos nuestros resultados filogenéticos en un contexto de caracteres morfológicos y químicos usados en la taxonomía tradicional. Teniendo en cuenta las evidencias obtenidas a partir de caracteres moleculares, morfológicos y químicos se identificaron un total de 18 linajes de Xanthoparmelia con categoría de especie que aparecen en el centro de México. Sin embargo, muchas especies tradicionalmente circunscritas no formaron grupos monofiléticos. Este conflicto indica que la taxonomía y delimitación de especies en el género Xanthoparmelia requiere revisión y enfatiza la importancia de los datos moleculares para una delimitación más robusta de especies en este género

    1863-07-15 Dudley H. Leavitt requests a discharge

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    https://digitalmaine.com/cw_me_3rd_regiment_corr/1472/thumbnail.jp

    1863-06-22 Dudley Leavitt requests his discharge

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    https://digitalmaine.com/cw_me_2nd_regiment_corr/1446/thumbnail.jp

    1863-09-26 Dudley H. Leavitt requests discharge as he is 4 months overdue for release

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    https://digitalmaine.com/cw_me_2nd_regiment_corr/1372/thumbnail.jp

    Theoretical Limb Darkening for Classical Cepheids: II. Corrections for the Geometric Baade-Wesselink Method

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    The geometric Baade-Wesselink method is one of the most promising techniques for obtaining a better calibration of the Cepheid period-luminosity relation by means of interferometric measurements of accurate diameters. In this paper we present new wavelength- and phase-dependent limb darkening corrections based on our time-dependent hydrodynamic models of the classical Cepheid zeta Gem. We show that a model simulation of a Cepheid atmosphere, taking into account the hydrodynamic effects associated with the pulsation, shows strong departures from the limb darkening otherwise predicted by a static model. For most of its pulsational cycle the hydrodynamic model predicts a larger limb darkening then the equivalent static model. The hydrodynamics affects the limb darkening mainly at UV and optical wavelengths. Most of these effects evolve slowly as the star pulsates, but there are phases, associated with shocks propagating into the photosphere, in which significant changes in the limb darkening take place on time-scales of the order of less than a day. We assess the implication of our model LD corrections fitting the geometric Baade-Wesselink distance of zeta Gem for the available near-IR PTI data. We discuss the effects of our model limb darkening on the best fit result, and analyze the requirements needed to test the time-dependence of the limb darkening with future interferometric measurements.Comment: 22 pages, 5 figures, to be published on the Astrophysical Journal, June 1 2003 issu

    Analysis to Action: A Guidebook For Conflict-Sensitive USAID Programming in Africa

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    https://nsuworks.nova.edu/hcas_dcrs_facbooks/1039/thumbnail.jp
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