Calibrated stellar models for metal-poor population

We extend to lower metallicities recent evolutionary computations devoted to Magellanic Clouds stars, presenting and discussing new stellar models with Z=0.0002, 0.0004, 0.0006, 0.001 and suitable assumptions about the original He content. As in the previous paper, evolutionary results are compared with observational data to properly calibrate the assumptions about the efficiency of the surface convection. On this basis, we follow the evolution of stellar models in the mass range 0.6 to 11Mo from the Main Sequence (MS) to the C ignition or the onset of thermal pulses in the advanced Asymptotic Giant Branch (AGB) phase, presenting cluster isochrones covering the range of ages from 20 Myr to 20 Gyr. Selected predictions constraining the cluster ages are discussed, presenting a calibration of the difference in magnitude between the luminous MS termination and the He burning giants in terms of the cluster age. Both evolutionary tracks and isochrones are available at the URL http://astro.df.unipi.it/SAA/PEL/Z0.html. Data files are also available at the CDS.Comment: In publication on Astronomy and Astrophysic

A Tutorial on HTML

The World Wide Web is one large web of electronic documents. These documents are accessible to anyone connected to the Net using a browser. The design of a web page is crucial for presenting information in a manner that is most comp elling to read. This design is possible because of a special language called HTML. This paper aims at giving a very brief in sight into the concepts of the Hyper Text Markup Language. A few important HTML tags are described to give the user a very basic working knowledge of the language

A new catalog of photometric redshifts in the Hubble Deep Field

Using the newly available infrared images of the Hubble Deep Field in the J, H, and K bands and an optimal photometric method, we have refined a technique to estimate the redshifts of 1067 galaxies. A detailed comparison of our results with the spectroscopic redshifts in those cases where the latter are available shows that this technique gives very good results for bright enough objects (AB(8140) < 26.0). From a study of the distribution of residuals (Dz(rms)/(1+z) ~ 0.1 at all redshifts) we conclude that the observed errors are mainly due to cosmic variance. This very important result allows for the assessment of errors in quantities to be directly or indirectly measured from the catalog. We present some of the statistical properties of the ensemble of galaxies in the catalog, and finish by presenting a list of bright high-redshift (z ~ 5) candidates extracted from our catalog, together with recent spectroscopic redshift determinations confirming that two of them are at z=5.34 and z=5.60.Comment: 28 pages, 12PS+4JPEG figures, aaspp style. Accepted for publication in The Astrophysical Journal. The catalog, together with a clickable map of the HDF, Tables 4 and 5 (HTML, LaTeX or ASCII format), and the figures, are available at http://bat.phys.unsw.edu.au/~fsoto/hdfcat.htm

Enhancing Knowledge Management With XML

Knowledge Management involves gathering, categorizing, storing and sharing of knowledge. There are several available tools that can be used to build a knowledge management infrastruc-ture to achieve its goals. This paper discusses issues involved in designing an information Portal using XML-based tools. As compared to traditional HTML-based portals, use of XML offers several benefits - it provides a great way of efficiently aggregating, classifying, and presenting both structured and unstructured content over the Internet or similar networks

Accelerating Bayesian hierarchical clustering of time series data with a randomised algorithm

We live in an era of abundant data. This has necessitated the development of new and innovative statistical algorithms to get the most from experimental data. For example, faster algorithms make practical the analysis of larger genomic data sets, allowing us to extend the utility of cutting-edge statistical methods. We present a randomised algorithm that accelerates the clustering of time series data using the Bayesian Hierarchical Clustering (BHC) statistical method. BHC is a general method for clustering any discretely sampled time series data. In this paper we focus on a particular application to microarray gene expression data. We define and analyse the randomised algorithm, before presenting results on both synthetic and real biological data sets. We show that the randomised algorithm leads to substantial gains in speed with minimal loss in clustering quality. The randomised time series BHC algorithm is available as part of the R package BHC, which is available for download from Bioconductor (version 2.10 and above) via http://bioconductor.org/packages/2.10/bioc/html/BHC.html. We have also made available a set of R scripts which can be used to reproduce the analyses carried out in this paper. These are available from the following URL. https://sites.google.com/site/randomisedbhc/

Slovenian Virtual Gallery on the Internet

The Slovenian Virtual Gallery (SVG) is a World Wide Web based multimedia collection of pictures, text, clickable-maps and video clips presenting Slovenian fine art from the gothic period up to the present days. Part of SVG is a virtual gallery space where pictures hang on the walls while another part is devoted to current exhibitions of selected Slovenian art galleries. The first version of this application was developed in the first half of 1995. It was based on a file system for storing all the data and custom developed software for search, automatic generation of HTML documents, scaling of pictures and remote management of the system. Due to the fast development of Web related tools a new version of SVG was developed in 1997 based on object-oriented relational database server technology. Both implementations are presented and compared in this article with issues related to the transion between the two versions. At the end, we will also discuss some extensions to SVG. We will present the GUI (Graphical User Interface) developed specially for presentation of current exhibitions over the Web which is based on GlobalView panoramic navigation extension to developed Internet Video Server (IVS). And since SVG operates with a lot of image data, we will confront with the problem of Image Content Retrieval

Topic Maps and TEI - Using Topic Maps as a Tool for Presenting TEI Documents

This paper describes a method used by the website of the New Zealand Electronic Text Centre (NZETC), in which Topic Maps are used as a tool for presenting TEI-encoded texts in HTML form. Many electronic text archives transform their TEI texts into HTML for publishing their texts on the World Wide Web. Typically each chapter or page is transformed from TEI into a separate web page. Such a method produces websites that have the same structure as a physical book. However, TEI is more expressive than HTML and can encode many other features of interest than just chapters, pages, and paragraphs. For example, TEI is also used to encode information about people and places and events, as well as literary criticism, and linguistic analysis. Indeed, TEI is designed to be extended to suit all kinds of scholarly needs. These more complex aspects of text encoding are more difficult to transform into HTML. Because TEI is designed to be convenient for scholars to encode complex information, rather than for readers to understand it, it is necessary to transform the TEI into another form suitable for display. For instance, where a TEI corpus includes references to people, these references might be collated together to produce an index. For practical purposes, it is often necessary to extract information from TEI into a database, so that it can be queried conveniently and transformed into a web site. The new "Topic Map" standard of the International Standards Organisation is identified as a suitable technology for solving this problem. A topic map is a kind of Web database with an extremely flexible structure. This paper describes a framework for using TEI in conjunction with Topic Maps to produce a large website which can be navigated easily in many directions