3,445 research outputs found
The high energy limit of the trajectory representation of quantum mechanics
The trajectory representation in the high energy limit (Bohr correspondence
principle) manifests a residual indeterminacy. This indeterminacy is compared
to the indeterminacy found in the classical limit (Planck's constant to 0)
[Int. J. Mod. Phys. A 15, 1363 (2000)] for particles in the classically allowed
region, the classically forbiden region, and near the WKB turning point. The
differences between Bohr's and Planck's principles for the trajectory
representation are compared with the differences between these correspondence
principles for the wave representation. The trajectory representation in the
high energy limit is shown to go to neither classical nor statistical
mechanics. The residual indeterminacy is contrasted to Heisenberg uncertainty.
The relationship between indeterminacy and 't Hooft's information loss and
equivalence classes is investigated.Comment: 12 pages of LaTeX. No figures. Incorporated into the "Proceedings of
the Seventh International Wigner Symposium" (ed. M. E. Noz), 24-29 August
2001, U. of Maryland. Proceedings available at
http://www.physics.umd.edu/robo
The Energetic Gamma-Ray Experiment Telescope (EGRET) Science Symposium
The principle purpose of this symposium is to provide the EGRET (Energetic Gamma-Ray Experiment Telescope) scientists with an opportunity to study and improve their understanding of high energy gamma ray astronomy. The Symposium began with the galactic diffusion radiation both because of its importance in studying galactic cosmic rays, galactic structure, and dynamic balance, and because an understanding of its characteristics is important in the study of galactic sources. The galactic objects to be reviewed included pulsars, bursts, solar flares, and other galactic sources of several types. The symposium papers then proceeded outward from the Milky Way to normal galaxies, active galaxies, and the extragalactic diffuse radiation
International terrorism and the american dream: A dialectical fairytale
La construcción que hoy día se hace del terrorismo en el sistema internacional es parte
de nuestros mundos de ensueño de consumo masivo confrontado con las imágenes del
sueño americano. Estos mundos ideales proporcionan los discursos hegemónicos de una
política paneuropea y universalista que asesina a un gran número de civiles inocentes con
fines políticos, actos de terrorismo, al mismo tiempo que niega que tales actos constituyan
terrorismo. La violencia utilizada se representa como un sacrificio compartido y necesario
para el sueño americano, sugiriendo una unidad, de otra manera inexistente, supuestamente
en “defensa propia” frente al terrorismo. En realidad, lo que se está consumando no son
acciones contra el terrorismo y la guerra de agresión, sino guerra de agresión y terrorismo
en sí mismos haciéndose pasar por la defensa de las comunidades imaginadas de la nación
y “Occidente”. El artículo hace hincapié especialmente en los medios de comunicación y en
las películas de Hollywood, incluyendo las redes sociales. El trabajo se basa en el análisis
del sistema-mundo, académicos de Relaciones Internacionales y teóricos de la cultura, los
medios y la comunicación para analizar los usos del terrorismo hoy en día. Al mismo tiempo,
el artículo se basa en teóricos críticos y en intelectuales públicos, desde Edward Said a
Judith Butler o el Papa Francisco, para criticar las oposiciones binarias y orientalistas de
los discursos paneuropeos actuales sobre terrorismo internacional, de manera que queden
expuestas sus complejidades y realidades, históricamente y en la actualidadToday’s framing of terrorism in the international system is part of our contemporary
dreamworlds of mass consumption set against images of the American Dream. These
dreamworlds provide the hegemonic discourses of a European universalist foreign policy
that kills huge numbers of innocent non-combatants for political purposes, acts of terrorism,
while denying that such acts constitute terrorism. The violence used is represented as a
necessary and shared sacrifice for the American Dream, suggesting a unity, otherwise
lacking, supposedly in “self-defense” against terrorism. In reality, what is being consumed
are not actions against terrorism and aggressive war, but aggressive war and terrorism
themselves masquerading as a defense of the imagined communities of the nation and “the
West”. The focus of this article is especially on media and Hollywood films, including social
media. The work draws on both world-systems analysis, international relations scholars,
and theorists of culture, media and communication to analyze the uses of terrorism today.
Simultaneously the article draws on critical theorists and public intellectuals, from Edward
Said to Judith Butler to Pope Francis, to critique the binary Orientalist oppositions of today’s
pan-European discourses on international terrorism, in ways that expose their complexities
and realities, historically and currentl
Vibration Characteristics Of Free Thin Cylindrical Shells
This paper considers the flexural vibrations of free thin circular cylinders. A frequency equation is derived using free-free characteristic beam functions to represent the variation of mid-surface shell displacement components, u, v and w, with respect to the axial direction. Timoshenko strain-displacement relations for thin cylinders are used to determine elastic vibratory strain energy. Energy methods are applied to obtain the frequency equation and associated amplitude ratios for each of its roots. This energy solution is checked experimentally using a vibration exciter and numerically using the SABOR IV finite element program. With minor modification, the frequency equation conforms to the one obtained in a similar way by Arnold and Warburton for cylinders with clamped ends and simply supported ends. Thus the proposed form of frequency equation, by accommodating a greater variety of boundary conditions, simplifies the task of determining cylinder vibration characteristics. © 1974 by ASME
Survey of the Macrobenthic Community in Ferguson Lake, Saline County, Arkansas
One hundred thirty benthic samples were collected on 33 visits to Ferguson Lake, Saline County, Arkansas, between May 1997 and October 2000. Sediments were visually examined and described, and some were returned to the lab for sediment oxygen demand (SOD) analysis. Fourteen taxa, representing five phyla of invertebrates, were identified. In all samples, oligochaetes, chaoborids, and chironomids comprised the majority of individuals, reaching densities up to 7449, 14,208, and 8783 per m2, respectively. When seasonally grouped, largest total abundances and greatest abundances of most taxa were collected during the winter months (December-February). A minor abundance peak occurred in July due to a mid-year generation of Chaoborus. Some significant differences in abundance between seasons were present. The number of taxa collected per sample was also highest in winter but not significantly different from other seasons. Community diversity indicators were lowest in summer. Sediments over most of the lake consisted of a variable thickness (1 to 4 cm) layer of woody detritus above a deeper, rich, thinly divided mix of organic muck and inorganic particulates. Too little variation in sediments existed to test for macrobenthos preferences. The SOD tests revealed a nearly complete oxygen depletion in the chamber in 24 hours
Morphometry and Limnology of Ferguson Lake, Saline County, Arkansas
To more fully understand Ferguson Lake as an ecosystem and eventually relate its water quality and production potential to fisheries management, several limnological variables were sampled monthly from April 1997 through March 1999. Vertical profiles of temperature and dissolved oxygen were recorded, and water samples from 0.5 m. depth were tested for turbidity, pH, total alkalinity, total hardness, ortho-phosphate, nitrate-nitrogen, sulfate, iron and specific conductance. Evaporation rate experiments, spillway discharge and rainfall records were used to estimate lake hydrology. Depth transects on the lake and USGS topographic maps were used to measure and calculate morphometric and watershed features. The lake is essentially the deep end of a swamp (dmax =4.27 m.; dmean =1.92 m.) which is dominated by a lowland hardwood species-pine mix. Numerous cypress (Taxodium distichum) and tupelo gum (Nyssa aquatic) trees stand in the uppermost one-third of the lake. The rapid deposition and slow decomposition of organic debris on the lake bottom are the primary contributors to the brown water, relatively low pH, and hypoxia in and near the sediments from May through November. There was no evidence of thermal stratification, and pH ranged between 6 and 7, except for brief periods of rapid photosynthesis during the summers. Alkalinity, hardness and specific conductance were quite low, compared to most natural waters in this region. Phosphate, nitrate and sulfur were also comparatively low, and iron was low except after rainfall events which resulted in fairly heavy runoff
The Clustering Of Galaxies Around Radio-Loud AGNs
We examine the hypothesis that mergers and close encounters between galaxies
can fuel AGNs by increasing the rate at which gas accretes towards the central
black hole. We compare the clustering of galaxies around radio-loud AGNs with
the clustering around a population of radio-quiet galaxies with similar masses,
colors and luminosities. Our catalog contains 2178 elliptical radio galaxies
with flux densities greater than 2.8 mJy at 1.4 GHz from the 6dFGS survey. We
find that radio AGNs with more than 200 times the median radio power have, on
average, more close (r<160 kpc) companions than their radio-quiet counterparts,
suggestive that mergers play a role in forming the most powerful radio
galaxies. For ellipticals of fixed stellar mass, the radio power is not a
function of large-scale environment nor halo mass, consistent with the radio
powers of ellipticals varying by orders of magnitude over billions of years.Comment: 12 pages, 6 figure
Ways to Clear Worthless Brush for Pasture Use
There\u27s no shortage of total permanent pasture in the state to meet current production needs. But individual farm operators sometimes wish to convert a particular area or tract of brushland to pasture. How can this be done
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