Vegas Research Articles

Introduction to Parallel Processing

Behrooz Parhmi Plenum Press, New York, 1999, 532 pp. ISBN 0-306-45970-1, $88.00 The book is organized in a very structured way making it suitable for use in a senior-level undergraduate or an introductory-level graduate course in computer science/engineering. While being successful in covering the main topics of parallel processing, the author has managed to arrive at an evenly divided book with fairly self-contained sections. As shown in page (xi), the book is comprised of six parts with each part containing four chapters. In the book, theoretical models of parallel processing are described and accompanied by techniques for exact analysis of parallel machines. The focus of the book is mainly on hardware issues, and software aspects such as parallel compilers/operating systems and concurrent programming are addressed in less detail. From the start, the author motivates the problem by explaining the continuing need for parallel processing regardless of advances in technology. Chapter 1 dwells on basic concepts of parallel processing. Fundamental computations including semigroup and parallel prefix computations are covered in Chapter 2. The reader here is introduced to simple parallel architectures such as linear array, binary tree, and 2D mesh. Most common communication primitives such as one to one routing, broadcasting, and sorting are described in conjunction with the said three architectures. In Chapter 3, asymptotic complexity along with complexity classes (NP-complete, NP, P, NC, etc.) is covered in detail. The author has done a good job in clarifying facts and fallacies of parallel processing. Chapter 4 concludes the first part of the book by intruding Flynn's classification of parallel machines, the PRAM model, and global versus distributed memory. Part II starts out with the PRAM as an extreme model for parallel computation. It then describes, in more detail than earlier chapters, the basic parallel algorithms. Algorithms aimed at systems with shared memory are discussed in Chapter 6. Synthesis and analysis of sorting networks are presented in Chapter 7, which is followed by more coverage of architectures designed for such parallel algorithms as DFT and FFT. Part III is devoted to mesh-based networks with associated algorithms. These networks are important due to their simplicity and low communication delay; they form the backbone of many parallel machines. I think, therefore, devotion of the whole part to mesh topologies is appropriate and well justified. Part IV covers the popular networks proposed over the past decades to serve as the underlying topology of parallel machines. These networks generally have low diameter and node degree and offer the familiar trade-off between speed and cost. Part V presents broad topics such as data flow, load balancing, and scheduling as well as system issues. Emulation (embedding) among parallel architectures is also discussed in a general way, with specific problems given at the end of the chapter. Finally Part VI adds much value to the text by addressing the implementation issues and introducing the contemporary parallel machines of different types. The book also contains useful and informative examples, illustrations, and problems. The end-of-chapter exercises are rigorous and relate directly to the subject just covered. References are recent and are taken from highly visible conferences/journals and books in the discipline. Finally, it should be pointed out that writing a book on computer architecture in general and parallel processing in particular is a challenge considering recent advances in technology. The author should be congratulated for composing a book, which appears to survive for years to come as it addresses, along with contemporary algorithms and architectures, concepts and innovations with little or no dependence on the current technology. Shahram Latifi University of Nevada, Las Vegas

Death in Vegas: Seduction, Kitsch, and Sacrifice

Death in Vegas: Seduction, Kitsch, and Sacrifice

Cinematic Re-Presentations of Las Vegas: Reality, Fiction and Compulsive Consumption

La these de la « classe creative » (Florida, 2002b) a suscite un large debat en science regionale. En mettant en avant la creativite comme competence cle du regime de croissance economique actuel, elle renouvelle l’analyse du role des villes au sein d’une economie de la connaissance en postulant que celles-ci doivent attirer et organiser les individus creatifs afin d’atteindre des sentiers vertueux de competitivite. A partir des travaux preliminaires qui ont suscite son developpement aux Etats-Unis mais egalement en menant une synthese du debat et des developpements dont elle a ete l’objet, cet article propose un panorama exhaustif de la these de la « classe creative » pour mettre en evidence, en depit de certaines de ses limites, l’apport qu’elle peut representer pour la science regionale.

The Story of Guadalupe: Luis Laso de la Vega's Huei tlamahuiçoltica of 1649, edited and translated by Lisa Sousa, Stafford Poole, CM., and James Lockhart.

"The Story of Guadalupe: Luis Laso de la Vega's Huei tlamahuiçoltica of 1649, edited and translated by Lisa Sousa, Stafford Poole, CM., and James Lockhart.." Canadian Journal of History, 35(1), pp. 192–193

Good Stuff Cheap

Gina Vega interviews Jerry Ellis, Founder and CEO, Building #19

ISOPHOT Observations of Dust Disks around Main Sequence (Vega-Like) Stars

The photometer (ISOPHOT) on the Infrared Space Observatory (ISO) has proved to be invaluable for investigating the dust around main sequence stars (both prototypes and candidate Vega-like stars). The long wavelength camera (at 60 and 90 μm) has been used to map the area around the stars to establish whether the dust disk is extended. Low-resolution spectra between 5.8 and 11.6 μm show whether the dust is composed of silicate grains, and whether molecular features are present. The four prototype Vega-like stars (Vega, β Pic, Fomalhaut, ϵ Eri) are studied, as well as eight other stars, which are main sequence stars with cool dust associated with them. We find that the spectra of β Pic, 49 Cet, HD98800, and HD135344 show excess emission from the cool dust around the star, HD144432 and HD139614 show silicate dust emission, HD169142 and HD34700 show emission features from carbon-rich molecules (possibly PAHs, polycyclic aromatic hydrocarbon molecules), and HD142666 shows emission features from both carbon-rich molecules and silicate dust. Up to 11.6 μm, the emission from Vega, Fomalhaut, and ϵ Eri is dominated by the stellar photosphere. At 60 and 90 μm, the extended dust emission is mapped, and the disk resolved in eight cases. The dust mass in the disks is found to range from around 10 −9 to 10 −4 M ⊙. Since several of the stars are younger than the Sun, and the disks have sufficient material of the type found in the Solar System, these disks could be in the early stages of planet formation.

Partial left ventriculectomy for the treatment of end-stage dilated cardiomyopathy.

To report our initial experience of the first 5 cases of partial left ventriculectomy (PLV or Batista operation), a new surgical therapy for treatment of end-stage dilated cardiomyopathy in China. From April to August 1998, 5 patients with idiopathic dilated cardiomyopathy received PLV at Anzhen Hospital. The mean age of the patients was 48.4 years (range: 42 to 53 years). Three patients were in New York Heart Association (NYHA) class III and 2 in class IV. All patients had mitral valve insufficiency (3 moderate and 2 severe) and 1 had severe tricuspid valve insufficiency in addition preoperatively. Cardiopulmonary bypass and cardiac arrest with cold blood cardioplegia were used in all patients. The average weight of the resected left ventricle muscle was 46.3 g. All patients underwent mitral annuloplasty and 1 plus tricuspid annuloplasty (De Vega). Echocardiography demonstrated a significant decrease in left ventricular diastolic diameter (8.4 +/- 1.1 cm to 5.4 +/- 0.4 cm, P < 0.01) and an increase in ejection fraction (17.78% +/- 6.26% to 34.82% +/- 3.18%, P < 0.025). One patient died of heart failure on the 6th postoperative day. The mean follow-up period of the 4 discharged patients were 4 months (from 3 to 6 months). One were in NYHA class I and 3 in class II; all had a normal life. Batista operation is a new and valuable alternative of the surgical treatment for end-stage dilated cardiomyopathy and the long-term results need further studies.

Spectral Irradiance Calibration in the Infrared. XI. Comparison of α Bootis and 1 Ceres with a Laboratory Standard

Infrared spectra of two celestial objects frequently used as flux standards are calibrated against an absolute laboratory flux standard at a spectral resolving power of 100 to 200. The spectrum of the K1.5III star, alpha Boo, is measured from 3 microns to 30 microns and that of the C-type asteroid, 1 Ceres, from 5 microns to 30 microns. While these 'standard' spectra do not have the apparent precision of those based on calculated models, they do not require the assumptions involved in theoretical models of stars and asteroids. Specifically they provide a model-independent means of calibrating celestial flux in the spectral range from 12 microns to 30 microns where accurate absolute photometry is not available. The agreement found between the spectral shapes of alpha Boo and Ceres based on laboratory standards, and those based on observed ratios to alpha CMa (Sirius) and alpha Lyr (Vega), flux calibrated by theoretical modeling of these hot stars strengthens our confidence in the applicability of the stellar models as primary irradiance standards.

La configuración Constitucional del Tribunal de Cuentas en España

Con la premisa de que el derecho constitucional español ha prestado una escasa atención al estudio del Tribunal de Cuentas en España, y a su posición dentro del conjunto del ordenamiento constitucional, el autor hace un estudio sobre este Tribunal abarcando sus antecedentes; la posición constitucional que ocupa en el ordenamiento; su organización y funciones, tanto la fiscalizadora como la de enjuiciamiento contable y la presencia que tiene frente a la opinión pública. En el artículo se hace un análisis de la naturaleza jurídica de la institución, llegándose a precisar las relaciones que mantiene con los órganos del poder del Estado. Además, examina la relación que existe entre el Tribunal y los órganos de control externo de las comunidades autónomas, exponiendo al respecto las resoluciones que ha emitido el Tribunal Constitucional, de entre las que sobresalen aquellas que establecen que el Tribunal de Cuentas es el órgano supremo, pero no el único, de fiscalización, ya que ni la Constitución ni la Ley Orgánica del Tribunal excluyen la existencia de los órganos de control externo de las comunidades autónomas.

Hey, Feds: Don't Botch the Workfare Miracle—Vegas

Hey, Feds: Don't Botch the Workfare Miracle—Vegas

Near the lights of Vegas, chemists are on a roll.

Near the lights of Vegas, chemists are on a roll.

An Explanation of the [ITAL]ROSAT[/ITAL] High-Resolution Imager Ultraviolet Sensitivity

The UV sensitivity to bright stars observed during operations of the high-resolution imager (HRI) on the X-ray-XUV Roentgen Satellite (ROSAT) has been commonly interpreted as a result of enhanced transmission solely in the wavelength range 1500-1700 A of the HRI's UV/ion shield. We report on recent laboratory UV transmission measurements of HRI flight spare filters that show transmissions much higher than previously assumed for wavelengths longward of approximately 2000 A. We present a model for the UV response of the HRI based on these measurements. Using this model and the known UV spectra of the A stars Vega (α Lyrae, V = +0.03) and β Carinae (V = +1.68), we successfully predict the observed HRI count rates for these two stars.

Gaming: Vegas Pauses for Breath

Gaming: Vegas Pauses for Breath

A search for molecular gas components in prototypal Vega-excess systems

We report the results of a deep search for submillimetre lines of 12CO around the nearby main-sequence stars Vega (α Lyr), ε Eridanus, Fomalhaut (α PsA), β Leo and β Pictoris. Upper limits on CO masses about 10 to 100 times lower than those previously reported have been obtained. If ‘normal’ interstellar medium CO abundances are assumed, the data suggest that the gas:dust mass ratio is reduced by a factor of ≳ 103 below that found in molecular clouds. These apparently low values can be explained by photodissociation of CO in the stellar or, in the case of ε Eri, the interstellar UV radiation field. The predicted CO column densities are similar to our limits if the CO is not replenished. Although the β Pic disc has the highest dust mass, the large grain size results in a relatively low UV extinction to the central star, and so CO photodissociation can readily occur. It has been suggested by others that the CO could be replenished by the occasional infall of comets, and we place an upper limit on the rate of cometary accretion for ε Eri.

MAP-based Trigonometric Parallaxes of ALTAIR and VEGA

view Abstract Citations (11) References (12) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS MAP-based Trigonometric Parallaxes of ALTAIR and VEGA Gatewood, George ; de Jonge, Joost Kiewiet Abstract Trigonometric parallaxes for stars in the regions of the nearby main-sequence A stars Altair and Vega are derived from data collected with the Multichannel Astrometric Photometer (MAP) and associated Thaw refractor of the University of Pittsburgh's Allegheny Observatory. The weighted mean parallax of all trigonometric studies of Altair is now +0".1963±0".00077, corresponding to a distance modulus of 1.465±0.009 mag and an absolute visual magnitude of 2.22±0.012. Altair's diameter is 1.63±0.08 solar diameters. The weighted mean trigonometric parallax of all trigonometric studies of Vega is now 0".1300±0".00077, yielding a distance modulus of 0.570±0.013 and an absolute visual magnitude of 0.60±0.013. Vega's diameter is 2.68 + 0.06 solar diameters. The apparent motion of both stars is linear over the period of observation, strongly suggesting the absence of short-period (1-6 yr) stellar or brown dwarf companions to either star. We also find a parallax of 0".0155±0".0006 for the high proper motion F8 reference star BD +38°3231. The derived luminosity, UV excess, and high space motion of this star all indicate that it is a subdwarf. Publication: The Astrophysical Journal Pub Date: September 1995 DOI: 10.1086/176146 Bibcode: 1995ApJ...450..364G Keywords: STARS: DISTANCES; STARS: INDIVIDUAL NAME: ALTAIR; STARS: INDIVIDUAL NAME: VEGA; STARS: FUNDAMENTAL PARAMETERS; STARS: LOW-MASS; BROWN DWARFS full text sources ADS | data products SIMBAD (5)

"The Resonances of Words": Lope de Vega and Geoffrey Hill

Comparant un sonnet de Lope de Vega, sa traduction par J. M. Cohen et sa reecriture par G. Hill, l'A. tente de mettre en evidence les resonances bibliques, patristiques et petrarquistes dans la nature intertextuelle de la poesie espagnole classique et anglaise contemporaine

A reinterpretation of millimeter observations of nearby IRAS excess stars

We analyze new and previously published 1300, 870, and 800 micrometers, single-element bolometer observations of Vega (alpha Lyr), Formalhaut (alpha PsA), epsilon Eri, tau(sup1) Eri, and Beta Leo. We show that these data are consistent with models in which the dust disks around these stars are larger than the radio telescope beams with which they were observed; thus, these disks may be many hundreds of AU in radius or larger. Our interpretation of submillimeter/millimeter measurements of these stars also indicates that for some Infrared Astronomy Satellite (IRAS) IR excess stars the assumption that there is no astrophysical flux in the OFF beams, when using the standard ON-minus-OFF chopping technique and the chop distance is less than 1000AU, may be incorrect. Therefore, for IRAS IR excess stars within approximately 20 pc, virtually all submillimeter/millimeter chopping observations with chop throws less than may have subtracted away some or most of the flux associated with their circumstellar disks. Finally, we present new 1300 micrometers continuum observations of Vega made with chop throws of 500 and 1000 AU. These data are consistent with an interpretation in which Vega has a disk that is at least 1000AU in radius; this disk could have a region with much less material per beam area near 500 AU than at both 100 AU and 1000 AU, corresponding to a gap at the orbital distance of alpha Lyr B. The observations of Vega are also consistent with the assumption that the circumVega dust structure is unresolved. Thus, these new data very effectively illustrate that the 'standard' model of small, unresolved, dust structures around main-sequence IRAS IR excess stars is not unique. Maps of IRAS IR excess stars, which soon will be available from submillimeter/millimeter array detectors, will determine whether the paradigm shift we propose will occur.

We Are (Not) in This Together: The Caribbean Imaginary in "Encancaranublado" by Ana Lydia Vega

We Are (Not) in This Together: The Caribbean Imaginary in "Encancaranublado" by Ana Lydia Vega

Political Posturing on the Jewish Question by Lope de Vega and Faria e Sousa

Dans un de ses sonnets, Manuel Faria e Sousa consacre son travail a une longue diatribe antisemite de Lope de Vega. Cette position favorable aux juifs frappe par son caractere inhabituel a l'egard d'un peuple sujet au racisme. L'opinion de Faria e Sousa exprimee dans un contexte particulier: celui de la celebration par Lope de Vega de la violence inquisitoriale et de la justification des souffrances juives a travers l'histoire, se presente sous un caractere libre a propos des structures sociales de l'Espagne du XVII e siecle

Women and Writing in Puerto Rico: An Interview with Ana Lydia Vega

Women and Writing in Puerto Rico: An Interview with Ana Lydia Vega