Vegas Research Articles

Latino Heartland: Of Borders and Belonging in the Midwest by Sujey Vega

Latino Heartland: Of Borders and Belonging in the Midwest by Sujey Vega

Pyramid Hunters: The Iron Tomb by Peter Vegas

Pyramid Hunters: The Iron Tomb by Peter Vegas

Commentary on Tenureland

Commentary on Tenureland

Vega starspots may be light, not dark

Vega starspots may be light, not dark

Spots spotted on Vega star

Spots spotted on Vega star

Discovery of starspots on Vega

Context. The theoretically studied impact of rapid rotation on stellar evolution needs to be compared with these results of high-resolution spectroscopy-velocimetry observations. Early-type stars present a perfect laboratory for these studies. The prototype A0 star Vega has been extensively monitored in recent years in spectropolarimetry. A weak surface magnetic field was detected, implying that there might be a (still undetected) structured surface. First indications of the presence of small amplitude stellar radial velocity variations have been reported recently, but the confirmation and in-depth study with the highly stabilized spectrograph SOPHIE/OHP was required.

Aprendiendo del símbolo: imagen y referencia simbólica en los inicios del discurso arquitectónico posmoderno

El presente artículo efectúa una aproximación a la recuperación simbólica como argumento fundamental utilizado en la edición revisada de <em>Aprendiendo de Las Vegas</em> (Venturi, Scott Brown & Izenour, 1977), texto que asumió una importante repercusión en la teoría arquitectónica contramodernista. Esta recuperación, extremadamente crítica con la imposición vulgarizada del funcionalismo del estilo internacional, resulta coincidente con el rechazo de la neovanguardia norteamericana hacia el academicismo formalista del expresionismo abstracto, así como con la crisis del concepto de modernidad, propiciada por lo que —no sin cierta confusión— se conceptualizó como pensamiento posmoderno.

“Man, I really like Vegas” – Elvis Presley

“Man, I really like Vegas” – Elvis Presley

¿Puede considerarse portadores asintomáticos a los donantes de sangre seropositivos para Trypanosoma cruzi? Un estudio de validación en el proyecto CHICAMOCHA

Introducción: Identificar el deterioro clínico de individuos seropositivos para la enfermedad de Chagas requiere observar la evolución de personas con infección establecida por Trypanosoma cruzi (T.cruzi), libres de signos y síntomas de cardiomiopatía en una línea de base. Objetivo: Realizar una comparación entre donantes de bancos de sangre de Bucaramanga con serología positiva y negativa para T. cruzi. Metodología: La muestra consistió en donantes elegibles con pruebas de tamización positivas para T. cruzi, pero negativas para otros agentes infecciosos tamizados por los bancos de sangre. Estos registros fueron apareados con una muestra aleatoria 1:4 de donantes con pruebas negativas a todas las pruebas de tamización. Los participantes fueron entrevistados para conocer aspectos sociodemográficos y de percepción de su estado de salud, se realizó examen físico y se tomaron muestras de sangre para exámenes paraclínicos. Se reportaron las frecuencias y proporciones de los participantes. Se hicieron pruebas de hipótesis de no diferencias entre los dos grupos con la prueba Chi cuadrado, con un nivel alfa de significancia de 5%. Resultados: La muestra consistió en 2,132 donantes de sangre incluidos entre mayo de 2000 y marzo de 2004. Mediante prueba serológica se identificaron 488 (22.9%) seropositivos y 1644 (77.1%) seronegativos. Los seropositivos fueron mayores en edad, presentaron indicadores socioeconómicos menos favorables y menor afiliación a seguridad social con el régimen contributivo y tenían una mejor percepción de su salud en comparación con los seronegativos (p<0.05). No se observaron diferencias estadísticamente significativas en cuanto a la percepción del funcionamiento de los tres sistemas evaluados (cardiovascular, urinario y gastrointestinal) en ambos grupos. Conclusiones: Los hallazgos del estudio permiten inferir que los donantes de sangre seropositivos para T. cruzi podrían considerarse como portadores asintomáticos, sin evidencia clínica de cardiomiopatía. [Villar JC, Herrera VM, Vega A, Moso F. ¿Puede considerarse portadores asintomáticos a los donantes de sangre seropositivos para Trypanosoma cruzi? Un estudio de validación en el proyecto CHICAMOCHA. MedUNAB 2015; 18 (1):34-41]

A search for weak or complex magnetic fields in the B3V star Herculis

We obtained 128 high signal-to-noise ratio Stokes $V$ spectra of the B3V star $\iota$~Her on 5 consecutive nights in 2012 with the ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope, with the aim of searching for the presence of weak and/or complex magnetic fields. Least-Squares Deconvolution mean profiles were computed from individual spectra, averaged over individual nights and over the entire run. No Zeeman signatures are detected in any of the profiles. The longitudinal magnetic field in the grand average profile was measured to be $-0.24 \pm 0.32 $ G, as compared to $-0.22 \pm 0.32$ G in the null profile. Our observations therefore provide no evidence for the presence of Zeeman signatures analogous to those observed in the A0V star Vega by Lignieres et al. (2009). We interpret these observations in three ways. First, we compare the LSD profiles with synthetic Stokes $V$ profiles corresponding to organised (dipolar) magnetic fields, for which we find an upper limit of about 8~G on the polar strength of any surface dipole present. Secondly, we compare the grand average profile with calculations corresponding to the random magnetic spot topologies of Kochukhov & Sudnik (2013), inferring that spots, if present, of 2 degrees radius with strengths of 2-4 G and a filling factor of 50% should have been detected in our data. Finally, we compare the observations with synthetic $V$ profiles corresponding to the surface magnetic maps of Vega (Petit et al. 2010) computed for the spectral characteristics of $\iota$ Her. We conclude that while it is unlikely we would have detected a magnetic field identical to Vega's, we would have likely detected one with a peak strength of about 30 G, i.e. approximately four times as strong as that of Vega.

Comparison of TCP Variants in Wired-Cum-Wireless Environment

In this work, the performance of TCP in terms of throughput, goodput and congestion window behavior has been compared over different TCP variants (Tahoe, NewReno, SACK & Vegas) in wired-cum-wireless environment using Network Simulator (NS-2). Firstly, data has been sent from wired to wireless part and then from wireless to wired part. Simulation results show that in both the cases, in terms of throughput and goodput, TCP Tahoe performs best and TCP Vegas performs worst, but in terms of congestion window, TCP Vegas performs best.

Fizyolojik optik sinir başı çukurlaşması olan olgularda optik sinir başının heidelberg retina tomografisi ve optik koherens tomografi ile değerlendirilmesi: karşılaştırmalı çalışma

amaclandi. Gerec ve Yontem: Daha once glokom tanisi almamis ve rutin muayenede cup/disk orani (C/D) ≥ 0.6 olan fizyolojik cukurlasmali 57 olgunun 57 gozu ile C/D ≤ 0.4 olan 55 olgunun 55 gozu (normal grup) ve glokom birimimizde takipli erken glokomatoz hasari olan 56 hastanin 56 gozu calismaya alindi. Tum olgulara tam oftalmolojik muayene, gun ici intraokuler basinc takibi, gonyoskopi, santral kornea kalinligi (SKK), OKT ile RSLT kalinlik analizleri, HRT ile OSB parametreleri olcumleri ve GA testleri yapildi. Tum olgularin birer gozleri randomize olarak secildi. Bulgular: OKT ve HRT ile yapilan olcumlerde uc grup arasinda anlami farklilik oldugu goruldu (p<0.001). FC'li olgularin disk alaninin her iki gruptan anlamli olarak daha buyuk oldugu goruldu (p<0.001). FC'li olgularin cukurluk alani EG'lu olgularin cukurluk alanina benzer (p=0.085) bulunurken NK grubundaki olgulardan anlamli olarak yuksek bulunmustur (p<0.001). Rim alaninda beklendigi gibi FC'li ve NK' lu olgular arasinda fark yoktu (p=0.355) ve her iki grubun rim alani EG'lu olgulardan daha kalin olarak olculdu (p=0.002). FC, EG olgulari birbirinden ayirdedebilen en onemli OKT parametresinin ortalama RSLT kalinligi oldugu goruldu. OKT ve HRT ile yapilan olcumlerin FC'li olgulari ayirt etmedeki duyarliligi ve ozgunlugu karsilastirildiginda OKT'nin daha ustun oldugu goruldu. Sonuc: Optik koherens tomografi ve Heidelberg retina tomografisi genis optik sinir basi cukurlugu olan olgularin glokomdan ayriminda faydali olabilirler. Anahtar kelimeler: Fizyolojik cukurlasma, OKT, HRT, RSLT ABSTRACT Optic nerve head evaluation with heidelberg retinal tomography and optical coherence tomography in cases with physiologic large cups: a comperative study Objective: In this study we evaluated the optic nerve head (ONH) cupping parameters and thickness of retinal nerve fibre layers (RNFL) with Heidelberg retinal tomography (HRT) and optical coherence tomography (OCT) in patients with the diagnosis of physiological cupping whose intraocular pressure (IOP) and visual fields (VF) are normal but ONH cupping is more than 0.6. We then compared them with early glaucomatous (EG) patients and normal cases as control (NK). Material and Methods: The study enclosed 57 eyes of 57 patients having no previous diagnosis of glaucoma but with physiological cupping C/D≥0.6 on routine ophthalomological evaluation and 56 eyes of 56 early glaucomatous patients followed in our glaucoma unit. Control group (NK) consisted of 55 eyes of 55 cases with C/D≤0.4. All the patients were evaluated with whole ophthalmologic examination, intraocular pressure measurements, with gonioscopy and tests for thickness of central cornea (TCC), OCT, RNFL analyses, HRT, ONH parameters and VF tests. Only one eyes of each patient were randomly chosen. Results: All of the three groups were comparable with regards to TCC and refraction values (p=0.437 and p=0.478). But there was significant differences regarding OCT and HRT evaluations (p<0.001). Disc areas of PC cases were greater than those of other groups (p<0.001). The cupping area of PC cases was similar to those of EG cases (p=0.085) whereas it was significantly greater than those in control group (p<0.001). There was no difference in Rim area of PC and C groups as was expected (p=0.355) and Rim area of both groups was measured thicker than that of EG cases (p=0.002). It was seen that the most important OCT parameter differentiating PC and EG cases from each other was mean RNFL thickness. When the sensitivity and specificity of OCT and HRT measurements in differentiating PC cases were compared it was seen that OCT was superior. Conclusion: Optic coherence tomography and Heidelberg retinal tomography might be valuable in differentiating between large optic nerve head

Vitruvius and Borromeus in the Chancel of the Cathedral of Santiago de Compostela: Proportion and Symmetry according to Canon José de Vega y Verdugo (1656-1657)

En el archivo de la catedral de Santiago de Compostela, se conserva un memorial dirigido al cabildo, hoy conocido como Memoria sobre las Obras de la Catedral de Santiago, escrito entre 1656 y 1657 por el entonces joven canonigo Jose de Vega y Verdugo. Este excepcional manuscrito, joya de la literatura artistica barroca, recoge las ideas del autor para reformar la capilla mayor medieval, el recinto que alberga la tumba del apostol Santiago y que recibe a peregrinos procedentes de toda Europa. Sus propuestas, de contenido clasicista e ilustrado con varios dibujos de su mano, denotan la influencia del De Architectura, de Vitruvio, las Instructiones Fabricae, de Carlos Borromeo, y otros escritos de signo contrarreformista. Al estudio de tales fuentes se dedica el presente estudio.

RESOLVING VEGA AND THE INCLINATION CONTROVERSY WITH CHARA/MIRC

Optical and infrared interferometers definitively established that the photometric standard Vega (alpha Lyrae) is a rapidly rotating star viewed nearly pole-on. Recent independent spectroscopic analyses could not reconcile the inferred inclination angle with the observed line profiles, preferring a larger inclination. In order to resolve this controversy, we observed Vega using the six-beam Michigan Infrared Combiner on the Center for High Angular Resolution Astronomy Array. With our greater angular resolution and dense (u,v)-coverage, we find Vega is rotating less rapidly and with a smaller gravity darkening coefficient than previous interferometric results. Our models are compatible with low photospheric macroturbulence and also consistent with the possible rotational period of ~0.71 days recently reported based on magnetic field observations. Our updated evolutionary analysis explicitly incorporates rapid rotation, finding Vega to have a mass of 2.15+0.10_-0.15 Msun and an age 700-75+150 Myrs, substantially older than previous estimates with errors dominated by lingering metallicity uncertainties (Z=0.006+0.003-0.002).

Review of “The kitchen as laboratory” edited by César Vega, Job Ubbink, and Erik van der Linden

Vega C, Ubbink J, van der Linden E The Kitchen as Laboratory. Reflections on the Science of Food and Cooking. New York: Columbia University Press; 2012 312 pages, ISBN 978-0-231-15344-7

Europe's new Vega rocket completes flawless first flight

Europe's new Vega rocket completes flawless first flight

ASTD TechKnowledge 2012

eLearn Magazine's Editor in Chief, Jane Bozarth, provides a thorough overview of the American Society of Training and Development's Tech Knowledge (TK) 2012 conference, held in Las Vegas, Nevada. Keep reading for some key highlights.

Weak magnetic fields of intermediate‐mass stars

AbstractWe present the result of a highly sensitive spectropolarimetric study dedicated to intermediate‐mass stars. We report the detection of sub‐gauss surface magnetic fields on the normal, rapidly‐rotating A‐type star Vega and on the moderately‐rotating Am star Sirius A. These magnetic detections constitute the first evidence that tepid stars that do not belong to the class of Ap/Bp stars can also host magnetized photospheres, suggesting that a significant fraction of stars in this mass regime are magnetic. We present here the observational clues gathered so far to progress towards understanding the physical processes at the origin of this newly identified Vega‐like magnetism (© 2011 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic?

We aim at a highly sensitive search for weak magnetic fields in main sequence stars of intermediate mass, by scanning classes of stars with no previously reported magnetic members. After detecting a weak magnetic field on the normal, rapidly rotating A-type star Vega, we concentrate here on the bright star Sirius A, taken as a prototypical, chemically peculiar, moderately rotating Am star. We employed the NARVAL and ESPaDOnS high-resolution spectropolarimeters to collect 442 circularly polarized spectra, complemented by 60 linearly polarized spectra. Using a list of about 1,100 photospheric spectral lines, we computed a cross correlation line profile from every spectrum, leading to a signal-to-noise ratio of up to 30,000 in the polarized profile. We report the repeated detection of circularly polarized, highly asymmetric signatures in the line profiles, interpreted as Zeeman signatures of a large-scale photospheric magnetic field, with a line-of-sight component equal to $0.2 \pm 0.1$ G. This is the first polarimetric detection of a surface magnetic field on an Am star. Using rough estimates of the physical properties of the upper layers of Sirius A, we suggest that a dynamo operating in the shallow convective envelope cannot account for the field strength reported here. Together with the magnetic field of Vega, this result confirms that a new class of magnetic objects exists among non Ap/Bp intermediate-mass stars, and it may indicate that a significant fraction of tepid stars are magnetic.

Hanging out in Vegas

Hanging out in Vegas