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Search Results: 1 - 10 of 220776 matches for " Eric P. Smith "
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NASA Astrophysics Division Research and Analysis Program Statistics for the Period 2001-2009
Eric P. Smith
Physics , 2010,
Abstract: I describe the various elements of the NASA Science Mission Directorate's Astrophysics Division Research and Analysis Program and provide quantitative descriptions for factors such as proposal submission characteristics, proposal success rates, distribution of science areas for selected proposals, as well as funding distributions for the various program elements. I examine the variation of these factors with time to explore possible trends. The measures described here can be used as starting points for future discussions about issues related to balance within the astronomy and astrophysics research and analysis program.
Biplot and Singular Value Decomposition Macros for Excel
Ilya Lipkovich,Eric P. Smith
Journal of Statistical Software , 2002,
Abstract:
A new species of Osteocephalus (Anura: Hylidae) from Guyana
Smith,Eric N.; Noonan,Brice P.;
Revista de Biología Tropical , 2001,
Abstract: a new member of the genus osteocephalus is described from the pakaraima mountains of western guyana. this species is the smallest known member of the genus and is probably closely related to o. subtilis. both share a small size (less than 40 mm snout-vent length), large and bulgy eyes directed somewhat rostrally, green bones, smooth and brownish dorsal skin, relatively short and truncate snout, small tympanum, subgular and laterally expanded vocal sac, poorly developed subarticular and supernumerary tubercles, a supra-anal glandular ridge, and cream-white venter and subocular region. the new species can be distinguished from o. subtilis by the buff iris (vs black), smaller overall size (32.7 vs 35.8-38.8 mm snout-vent length), relatively larger toe disks, and less developed foot webbing. the cranium of the new species is well ossified, relatively reduced in width between the orbits, without an exposed frontoparietal fontanelle and with the anterior arm of the squamosal extending to about half the distance to the maxillary. the vocal sac is subgularly poorly developed and possess lateral extensions to the area behind the jaw angles. well developed supraocular and suprasquamosal cartilages give support to the enlarged eyes of this species.
A new species of Osteocephalus (Anura: Hylidae) from Guyana
Eric N. Smith,Brice P. Noonan
Revista de Biología Tropical , 2001,
Abstract: A new member of the genus Osteocephalus is described from the Pakaraima mountains of western Guyana. This species is the smallest known member of the genus and is probably closely related to O. subtilis. Both share a small size (less than 40 mm snout-vent length), large and bulgy eyes directed somewhat rostrally, green bones, smooth and brownish dorsal skin, relatively short and truncate snout, small tympanum, subgular and laterally expanded vocal sac, poorly developed subarticular and supernumerary tubercles, a supra-anal glandular ridge, and cream-white venter and subocular region. The new species can be distinguished from O. subtilis by the Buff iris (vs black), smaller overall size (32.7 vs 35.8-38.8 mm snout-vent length), relatively larger toe disks, and less developed foot webbing. The cranium of the new species is well ossified, relatively reduced in width between the orbits, without an exposed frontoparietal fontanelle and with the anterior arm of the squamosal extending to about half the distance to the maxillary. The vocal sac is subgularly poorly developed and possess lateral extensions to the area behind the jaw angles. Well developed supraocular and suprasquamosal cartilages give support to the enlarged eyes of this species. Un nuevo miembro del género Osteocephalus se describe de las monta as Pakaraima del oeste de Guyana. Es la especie más peque a del género y probablemente esté estrechamente relacionada con O. subtilis. Ambas especies comparten un tama o peque o (menos de 40 mm SVL), ojos grandes y sobresalientes, dirigidos hacia el rostro, huesos verdes, piel dorsal lisa, de tono casta o, hocico relativamente truncado y corto, tímpano peque o, saco vocal subgular y expandido lateralmente, tubérculos subarticulares y supernumerarios poco desarrollados, pliegue supra-cloacal glandular, vientre y área subocular de color blanco-crema. La nueva especie se distingue de O. subtilis por su iris casta o-mostaza (negro en O. subtilis), tama o menor (32.7 contra 35.8-38.8 mm SVL), discos de los dedos del pie relativamente más grandes, y membranas del pie menos desarrolladas. El cráneo de la nueva especie está bién osificado, relativamente reducido en ancho entre las orbitas de los ojos, sin una ventana frontoparietal expuesta, y con el brazo anterior del escuamoso extendiendose hasta cerca de la mitad de la distancia al maxilar. El saco vocal está poco desarrollado en el área subgular, y posee extensiones laterales hacia el área detrás del ángulo mandibular. Cartílagos supraoculares y supraescuamosales dan soporte a los grandes ojos de esta especi
NASA's Next Generation Space Telescope:Visiting a Time When Galaxies Were Young
Bernard D. Seery,Eric P. Smith,John C. Mather
Physics , 1998, DOI: 10.1364/OPN.9.7.000029
Abstract: With the discovery of galaxies that existed when the universe was very young (approximately 5 percent of its current age), of planets not in our own solar system, and with the tantalizing evidence that the conditions for life may have existed within our solar system on planets or moons outside of the earth system, the past year has seen an explosion of interest in astronomy. In particular, a new era of exploration and understanding seems imminent, where the connection between the existence for the conditions of life will be connected to the origin of galaxies, stars and planets within the Universe. Who knows where this quest for knowledge will take us? Keywords: Active Optics, Next Generation Space Telescope, Deployables, Detectors, NGST.
Key Changes to the GNU General Public License
Eric Smith
Technology Innovation Management Review , 2007,
Abstract: On June 29, 2007, the Free Software Foundation (FSF) issued the GNU General Public License Version 3. The issuance of GPLv3 marked the end of a remarkable public consultation process aimed at revamping the license to address issues that the FSF considers to be a threat to the Free Software movement, and to clarify issues that have been misunderstood or debated since the publications of GPL Version 2 (GPLv2). This article introduces the rationale for changing the GPL and introduces the changes that affect patents, Digital Rights Management (DRM), license compatibility, and the linking issue.
Trivial Spectrum of Free 1+1 Light-Cone Strings
Eric Smith
Physics , 1992, DOI: 10.1016/0370-2693(93)91065-U
Abstract: The BRST cohomology of 1+1 strings in a free light-cone gauge contains only the two-dimensional tachyon, and excludes all excited states of both matter and ghosts, including the special states that arise in the continuum conformal gauge quantization and in the $c = 1$ matrix models. This exclusion takes place at a very basic level, and therefore may signal some serious problems or at least unresolved issues involved in this gauge choice.
Light-Cone Gauge for 1+1 Strings
Eric Smith
Physics , 1992, DOI: 10.1016/0550-3213(92)90185-E
Abstract: Explicit construction of the light-cone gauge quantum theory of bosonic strings in 1+1 spacetime dimensions reveals unexpected structures. One is the existence of a gauge choice that gives a free action at the price of propagating ghosts and a nontrivial BRST charge. Fixing this gauge leaves a U(1) Kac-Moody algebra of residual symmetry, generated by a conformal tensor of rank two and a conformal scalar. Another is that the BRST charge made from these currents is nilpotent when the action includes a linear dilaton background, independent of the particular value of the dilaton gradient. Spacetime Lorentz invariance in this theory is still elusive, however, because of the linear dilaton background and the nature of the gauge symmetries.
Large-deviation principles, stochastic effective actions, path entropies, and the structure and meaning of thermodynamic descriptions
Eric Smith
Physics , 2011, DOI: 10.1088/0034-4885/74/4/046601
Abstract: The meaning of thermodynamic descriptions is found in large-deviations scaling of the fluctuations probabilities. The primary large-deviations rate function is the entropy, which is the basis for both fluctuation theorems and for characterizing the thermodynamic interactions of systems. Freidlin-Wentzell theory provides a general formulation of large-deviations scaling for non-equilibrium stochastic processes, through a representation in terms of a Hamiltonian dynamical system. A number of related methods now exist to construct the Freidlin-Wentzell Hamiltonian for many kinds of stochastic processes; one method due to Doi and Peliti, appropriate to integer counting statistics, is widely used in reaction-diffusion theory. Using these tools together with a path-entropy method due to Jaynes, we show how to construct entropy functions that both express large-deviations scaling of fluctuations, and describe system-environment interactions, for discrete stochastic processes either at or away from equilibrium. A collection of variational methods familiar within quantum field theory, but less commonly applied to the Doi-Peliti construction, is used to define a "stochastic effective action", which is the large-deviations rate function for arbitrary non-equilibrium paths. We show how common principles of entropy maximization, applied to different ensembles of states or of histories, lead to different entropy functions and different sets of thermodynamic state variables. Yet the relations of among all these levels of description may be constructed explicitly and understood in terms of information conditions. The example systems considered introduce methods that may be used to systematically construct descriptions with all the features familiar from equilibrium thermodynamics, for a much wider range of systems describable by stochastic processes.
The thermodynamic dual structure of linear-dissipative driven systems
Eric Smith
Physics , 2005, DOI: 10.1103/PhysRevE.72.036130
Abstract: The spontaneous emergence of dynamical order, such as persistent currents, is sometimes argued to require principles beyond the entropy maximization of the second law of thermodynamics. I show that, for linear dissipation in the Onsager regime, current formation can be driven by exactly the Jaynesian principle of entropy maximization, suitably formulated for extended systems and nonequilibrium boundary conditions. The Legendre dual structure of equilibrium thermodynamics is also preserved, though it requires the admission of current-valued state variables, and their correct incorporation in the entropy.
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