La sociedad de todas las voces

La idea de Bajtín en torno a la “heteroglosia dialogizada” y a las nociones de “voces” e “hibridez” de las que hace uso en sus trabajos teóricos y que los zapatistas refieren en sus comunicados oficiales y demandas políticas concretas. También plantearé que la visión resultante de la sociedad implica y nos insta a aceptar un principio político: “la interacción de voces igualmente audibles.” Este principio y la visión sobre la que éste se basa, suministran una base amplia para emprender importantes revisiones en las nociones tradicionales de los derechos humanos y la autodeterminación de los pueblos

Centrifugal Compressor Performance Making Enlightened Analysis Decisions

Tutoria

Letters between William Kerr\u27s secretary and Fred C. Evans

Letter concerning a circular for the summer school at Utah Agricultural College

El cosmopolitismo por venir: Derrida y el pensamiento fronterizo Latinoamericano

In an age where diversity is increasingly accepted as a value as well as a fact, ethico-political cosmopolitanism should propose a notion of global unity that is composed of rather than imposed on difference. Jacques Derrida and Walter Mignolo offer different versions of this view of cosmopolitanism. Derrida’s version is based on his notion of “democracy to come”. He characterizes this notion as an “unconditional” or “quasi-transcendental” injunction. Mignolo castigates this injunction as an “abstract universal”. He offers instead “a critical and dialogic” view of cosmopolitanism that is based more speci cally on the “colonial difference” or “border thinking” of Latin American subaltern groups. I argue that Derrida’s many implicit and explicit references to “voices” suggest a third alternative. This contender avoids certain problems in Derrida’s and Mignolo’s otherwise compelling views of cosmopolitanism. It also retains the universality of Derrida’s unconditional injunction but on the basis of the sort of worldly immanency urged by Mignolo’s border thinking. En una era donde la diversidad es progresivamente aceptada como un valor tanto como un hecho, el cosmopolitismo ético-político debe proponer una noción de unidad global que sea compuesta en vez de impuesta por la diferencia. Jacques Derrida y Walter Mignolo ofrecen versiones distintas de esta visión del cosmopolitismo. La versión de Derrida está basada en su noción de “la democracia por venir”. Caracteriza esta noción como un mandato “incondicional”  o cuasi transcendental. Mignolo se queja de este mandato como un “universal abstracto”. En su lugar ofrece una versión “crítica y dialógica” del cosmopolitismo basada más específicamente en “la diferencia colonial” o “el pensamiento fronterizo” de los grupos subalternos de América latina. Yo argumento que las referencias implícitas y explícitas de Derrida a las “voces” sugieren una tercera alternativa. Esta opción impide ciertos problemas que podemos atender en los convincentes puntos de vista de Derrida y Mignolo acerca del cosmopolitismo. También esta opción preserva la universalidad que tiene el mandato incondicional de Derrida pero sobre la base de un tipo de inmanencia  material impulsada  por el pensamiento fronterizo de Mignol

Detection and characterisation of stellar companions to transiting extrasolar planets through high resolution imaging

Since the discovery over two decades ago of the first `hot Jupiter', there has been persistent debate regarding the formation and origins of this class of planets. Some of the many `migration' theories for hot Jupiters suggest that these planets form in binary star systems, being driven inwards towards their host star by dynamical interactions. If this is the case, many hot Jupiters should be found in multiple stellar systems, which might only be resolved with dedicated high resolution imaging. An additional use for high resolution imaging is the detection of previously unresolved sources of contaminating light, which can significantly bias the properties derived for planets. Observations were carried out of 156 transiting exoplanet systems with lucky imaging, and of 46 systems with near infrared adaptive options, in order to detect stars at small angular separation, and to identify binary companions. The lucky imaging survey identified 39 plausible multiple systems, and historical measurements allowed binary orbits to be determined for WASP-77 and WASP-85. The AO survey identified companion stars to 26 of its 46 targets, although further work is needed to confirm the nature of several of these companions. A surprising trend among the confirmed binary companions, both in this work and others, is that they are generally much less massive than the planet host stars. This contrasts with studies of solar type stars have shown that binaries most often consist of components with similar masses, and further investigation is needed to explain the trend among exoplanet host stars. The Gaia survey has proved a useful source of additional astrometric data in this work, and is already competitive with lucky imaging for detection of companions. Future Gaia data releases will further improve this further, and detailed searches for binary companions present in the Gaia data are strongly encouraged

H2O and OH gas in the terrestrial planet-forming zones of protoplanetary disks

We present detections of numerous 10-20 micron H2O emission lines from two protoplanetary disks around the T Tauri stars AS 205A and DR Tau, obtained using the InfraRed Spectrograph on the Spitzer Space Telescope. Follow-up 3-5 micron Keck-NIRSPEC data confirm the presence of abundant water and spectrally resolve the lines. We also detect the P4.5 (2.934 micron) and P9.5 (3.179 micron) doublets of OH and 12CO/13CO v=1-0 emission in both sources. Line shapes and LTE models suggest that the emission from all three molecules originates between ~0.5 and 5 AU, and so will provide a new window for understanding the chemical environment during terrestrial planet formation. LTE models also imply significant columns of H2O and OH in the inner disk atmospheres, suggesting physical transport of volatile ices either vertically or radially; while the significant radial extent of the emission stresses the importance of a more complete understanding of non-thermal excitation processes.Comment: 9 pages, 3 figures, 1 table, aastex, to appear in the Astrophysical Journa

The c2d Spitzer spectroscopy survey of ices around low-mass young stellar objects, III: CH4

CH4 is proposed to be the starting point of a rich organic chemistry. Solid CH4 abundances have previously been determined mostly toward high mass star forming regions. Spitzer/IRS now provides a unique opportunity to probe solid CH4 toward low mass star forming regions as well. Infrared spectra from the Spitzer Space Telescope are presented to determine the solid CH4 abundance toward a large sample of low mass young stellar objects. 25 out of 52 ice sources in the $c2d$ (cores to disks) legacy have an absorption feature at 7.7 um, attributed to the bending mode of solid CH4. The solid CH4 / H2O abundances are 2-8%, except for three sources with abundances as high as 11-13%. These latter sources have relatively large uncertainties due to small total ice column densities. Toward sources with H2O column densities above 2E18 cm-2, the CH4 abundances (20 out of 25) are nearly constant at 4.7+/-1.6%. Correlation plots with solid H2O, CH3OH, CO2 and CO column densities and abundances relative to H2O reveal a closer relationship of solid CH4 with CO2 and H2O than with solid CO and CH3OH. The inferred solid CH4 abundances are consistent with models where CH4 is formed through sequential hydrogenation of C on grain surfaces. Finally the equal or higher abundances toward low mass young stellar objects compared with high mass objects and the correlation studies support this formation pathway as well, but not the two competing theories: formation from CH3OH and formation in gas phase with subsequent freeze-out.Comment: 27 pages, 7 figures, accepted by Ap