A catalogue of velocities in the cluster of galaxies Abell 85

We present a catalogue of velocities for 551 galaxies (and give the coordinates of 39 stars misclassified as galaxies in our photometric plate catalogue) in a region covering about 100'$\times$100' (0.94$\times$0.94 Mpc for an average redshift of 0.0555, assuming H$_\circ$=50 km s$^{-1}$ Mpc$^{-1}$) in the direction of the rich cluster Abell 85. This catalogue includes previously published redshifts by Beers et al. (1991) and Malumuth et al. (1992), together with our 367 new measurements. A total of 305 galaxies have velocities in the interval 13350-20000 km s$^{-1}$, and will be considered as members of the cluster. Abell 85 therefore becomes one of the clusters with the highest number of measured redshifts; its optical properties are being investigated in a companion paper.Comment: Accepted for publication in A&AS, Table 4 available in electronic form onl

Superconducting gap variations induced by structural supermodulation in BSCCO

We discuss the possibility that the strain field introduced by the structural supermodulation in Bi-2212 and certain other cuprate materials may modulate the superconducting pairing interaction. We calculate the amplitude of this effect, visible in scanning tunneling spectroscopy experiments, and thereby relate a change in the local superconducting gap with the change in the local dopant displacements induced by the supermodulation. In principle, since this modulation is periodic, sufficiently accurate x-ray measurements or ab initio calculations should enable one to determine which atomic displacements enhance pairing and therefore T_c.Comment: 4 pages, 3 figure

Hydrogen-Air-Steam Combustion Regimes In Large Volumes

Dangerous pressure waves can be generated by the combustion of H2-air-steam mixtures if ordinary deflagrations accelerate to high speed or undergo deflagration-to-detonation transition (DDT). The purpose of this paper is to estimate the potentially dangerous mixtures in large volumes. There is a limited experimental data base for flame acceleration and DDT of EL-airsteam mixtures in smaller geometries. There is concern about the possible explosive combustion in the Space Shuttle main engine exhaust duct at Vandenberg AFB. There are no relevant experimental data or valid theories at this large scale (duct width, W, ~ 10 m) to predict flame acceleration and DDT. We have estimated potentially dangerous mixtures by extrapolating correlations used at smaller scale based on the detonation cell width, X. In square ducts DDTs are possible if W/X \u3e 1. We delineate three combustion regions: nonflammable, weakly flammable, and strongly flammable and potentially detonable. The nonflammable region is the region outside the flammability limit where self-sustaining combustion cannot occur. Flammability limits are independent of scale in large volumes. The strongly flammable region, where dangerous flame acceleration or DDT is possible, is bounded by mixtures with X = 10 m. We estimate detonations are possible when there is less than 45% steam. The weakly flammable region, which lies between the other two, should support only slow combustion, where no significant pressure waves should be generated

Mate Marote: a BigData platform for massive scale educational interventions

In this paper we present Mate Marote, a web platform for massive scale educational interventions. We focus on the scaling requirements needed on these kind of deployments. We show the designed architecture, how these decisions solve the imposed requirements and the implementation. To test this development, we performed a small pilot intervention where the whole system was evaluated. We conclude that Mate Marote is ready for production deployment and enabled to middleto- massive scale interventions. For this purpose, we have deployed this platform in CEIBAL program at Uruguay with more than 100K potential users.Sociedad Argentina de Informática e Investigación Operativ

Mate Marote: a BigData platform for massive scale educational interventions

In this paper we present Mate Marote, a web platform for massive scale educational interventions. We focus on the scaling requirements needed on these kind of deployments. We show the designed architecture, how these decisions solve the imposed requirements and the implementation. To test this development, we performed a small pilot intervention where the whole system was evaluated. We conclude that Mate Marote is ready for production deployment and enabled to middleto- massive scale interventions. For this purpose, we have deployed this platform in CEIBAL program at Uruguay with more than 100K potential users.Sociedad Argentina de Informática e Investigación Operativ

A Wavelet-Based Algorithm for the Spatial Analysis of Poisson Data

Wavelets are scaleable, oscillatory functions that deviate from zero only within a limited spatial regime and have average value zero. In addition to their use as source characterizers, wavelet functions are rapidly gaining currency within the source detection field. Wavelet-based source detection involves the correlation of scaled wavelet functions with binned, two-dimensional image data. If the chosen wavelet function exhibits the property of vanishing moments, significantly non-zero correlation coefficients will be observed only where there are high-order variations in the data; e.g., they will be observed in the vicinity of sources. In this paper, we describe the mission-independent, wavelet-based source detection algorithm WAVDETECT, part of the CIAO software package. Aspects of our algorithm include: (1) the computation of local, exposure-corrected normalized (i.e. flat-fielded) background maps; (2) the correction for exposure variations within the field-of-view; (3) its applicability within the low-counts regime, as it does not require a minimum number of background counts per pixel for the accurate computation of source detection thresholds; (4) the generation of a source list in a manner that does not depend upon a detailed knowledge of the point spread function (PSF) shape; and (5) error analysis. These features make our algorithm considerably more general than previous methods developed for the analysis of X-ray image data, especially in the low count regime. We demonstrate the algorithm's robustness by applying it to various images.Comment: Accepted for publication in Ap. J. Supp. (v. 138 Jan. 2002). 61 pages, 23 figures, expands to 3.8 Mb. Abstract abridged for astro-ph submissio

Reproducibility of optical coherence tomography in vein grafts used for coronary revascularization

Background: Optical coherence tomography (OCT) is a high-resolution imaging modality able to provide near-histological images of vessel walls making it possible to distinguish intima and media layers of the vessel wall separately. The use of this imaging technique is increasing while data on the variability and reliability is lacking. The aim of this study was to investigate the reproducibility of frequency-domain OCT in vein grafts used for coronary revascularization.Methods: Five pullbacks were analyzed by the same analyst with a 1-month delay (intraobserver) and by two different analysts (interobserver). Five pairs of pullbacks from the same catheters and vein graft were also analyzed (inter pullback).Results: Optical coherence tomography showed low variability in intra- and interobserver analysis with relative differences of mean media and intima thicknesses and areas of less than 5% for most parameters.Relative differences of the same parameters in the inter pullback analysis were in the 5–15% range. Intra- and interobserver reliability was excellent (intraclass correlation coefficient [ICC] > 0.90) for intima thickness and intima, media and intima-media area measurements. Inter pullback reliability was good (ICC: 0.75–0.90) for intima and intima-media area measurements, and moderate to good for mean intima thickness measurements (ICC: 0.79; 0.7338–0.8284).Conclusions: Optical coherence tomography provides good reproducibility for the measurements of parameters relevant for the development of atherosclerosis in vein grafts.Clinical trial registration: ID NCT01834846