Organic Molecules in the Galactic Center. Hot Core Chemistry without Hot Cores

We study the origin of large abundances of complex organic molecules in the Galactic center (GC). We carried out a systematic study of the complex organic molecules CH3OH, C2H5OH, (CH3)2O, HCOOCH3, HCOOH, CH3COOH, H2CO, and CS toward 40 GC molecular clouds. Using the LTE approximation, we derived the physical properties of GC molecular clouds and the abundances of the complex molecules.The CH3OH abundance between clouds varies by nearly two orders of magnitude from 2.4x10^{-8} to 1.1x10^{-6}. The abundance of the other complex organic molecules relative to that of CH3OH is basically independent of the CH3OH abundance, with variations of only a factor 4-8. The abundances of complex organic molecules in the GC are compared with those measured in hot cores and hot corinos, in which these complex molecules are also abundant. We find that both the abundance and the abundance ratios of the complex molecules relative to CH3OH in hot cores are similar to those found in the GC clouds. However, hot corinos show different abundance ratios than observed in hot cores and in GC clouds. The rather constant abundance of all the complex molecules relative to CH3OH suggests that all complex molecules are ejected from grain mantles by shocks. Frequent (similar 10^{5}years) shocks with velocities >6km/s are required to explain the high abundances in gas phase of complex organic molecules in the GC molecular clouds. The rather uniform abundance ratios in the GC clouds and in Galactic hot cores indicate a similar average composition of grain mantles in both kinds of regions. The Sickle and the Thermal Radio Arches, affected by UV radiation, show different relative abundances in the complex organic molecules due to the differentially photodissociation of these molecules.Comment: 18 pages, 10 Postscript figures, uses aa.cls, aa.bst, 10pt.rtx, natbib.sty, revsymb.sty revtex4.cls, aps.rtx and aalongtabl.sty. Accepted in A&A 2006. version 2. relocated figures and tables. Language editor suggestions. added reference

An estimate of necessary effort in the development of software projects

International Workshop on Intelligent Technologies for Software Engineering (WITSE'04). 19th IEEE International Conference on Automated Software Engineering (Linz, Austria, September 20th - 25th, 2004)The estimated of the effort in the development of software projects has already been studied in the field of software engineering. For this purpose different ways of measurement such as Unes of code and function points, generally addressed to relate software size with project cost (effort) have been used. In this work we are presenting a research project that deals with this field, us'mg machine learning techniques to predict the software project cost. Several public set of data are used. The analysed sets of data only relate the effort invested in the development of software projects and the size of the resultant code. For this reason, we can say that the data used are poor. Despite that, the results obtained are good, because they improve the ones obtained in previous analyses. In order to get results closer to reality we should find data sets of a bigger size that take into account more variables, thus offering more possibilities to obtain solutions in a more efficient way.Publicad

History, poetry, and politics in Gaspar de Villagrá's : Historia de la nueva México

Gaspar de Villagrá’s Historia de la nveva Mexico (1610) has lingered on the margins of U.S. literary history for centuries. Embraced as a source of historical information, the poem was seldom seen as a work of literary merit. In the past four decades, however, critics of Chicano/a literature have paved the way for a reinterpretation of the poem that places Villagrá’s Historia at the onset of Chicano/a letters. But reclaiming the poem means addressing its politics as well. In this article, I analyze the ways in which history, poetry, and politics are intertwined in Villagrá’s Historia in ways that maximize ambiguity, open-endedness, and contradiction.La Historia de la Nueva Mexico (1610) de Gaspar de Villagrá ha permanecido en los márgenes de la historia literaria estadounidense hasta fechas recientes. Si bien se ha valorado con frecuencia su importancia como testimonio histórico, pocos estudiosos han defendido sus méritos literarios. Durante las últimas cuatro décadas, sin embargo, el creciente interés por el poema entre los expertos en la literatura chicana ha conseguido situar la historia de Villagrá en un lugar fundacional para las letras norteamericanas. La asignatura pendiente, en lo que a esta recuperación concierne, ha sido la de valorar el legado político del poema. En este artículo, analizo la forma en que la historia de Villagrá articula las tensiones entre historia, poesía y política potenciando la ambigüedad, la apertura y la contradicción

History, poetry, and politics in Gaspar de Villagrá's : Historia de la nueva México

Gaspar de Villagrá’s Historia de la nveva Mexico (1610) has lingered on the margins of U.S. literary history for centuries. Embraced as a source of historical information, the poem was seldom seen as a work of literary merit. In the past four decades, however, critics of Chicano/a literature have paved the way for a reinterpretation of the poem that places Villagrá’s Historia at the onset of Chicano/a letters. But reclaiming the poem means addressing its politics as well. In this article, I analyze the ways in which history, poetry, and politics are intertwined in Villagrá’s Historia in ways that maximize ambiguity, open-endedness, and contradiction.La Historia de la Nueva Mexico (1610) de Gaspar de Villagrá ha permanecido en los márgenes de la historia literaria estadounidense hasta fechas recientes. Si bien se ha valorado con frecuencia su importancia como testimonio histórico, pocos estudiosos han defendido sus méritos literarios. Durante las últimas cuatro décadas, sin embargo, el creciente interés por el poema entre los expertos en la literatura chicana ha conseguido situar la historia de Villagrá en un lugar fundacional para las letras norteamericanas. La asignatura pendiente, en lo que a esta recuperación concierne, ha sido la de valorar el legado político del poema. En este artículo, analizo la forma en que la historia de Villagrá articula las tensiones entre historia, poesía y política potenciando la ambigüedad, la apertura y la contradicción

Voces, gestos y signos : de oralidad a la escritura en "...Y no se lo tragó la Tierra" de Tomás Rivera

Abstract en inglés.This essay analyzes Tomás Riviera' s novel ". . . y no se lo tragó la tierra" as a\ud landmark in Chicano literary history. The article explores the way in which Riviera sets out to chronicle the transition from a cultural past marked by a communal oral culture to a cultural present dominated by writing. The moment of transition from one world to the other is seen in the final paragraph of the novel, in which the young protagonist communicates by gestures with a young person he sees in the distance. In thus moving from voice to silence, the main character (and with him the novelist) poetically envisions his readership, as well as the process by which silent writing (somewhat paradoxically) manages to capture and transmit the words and the expression of Chicano farmworkers in the 1950s

"El llano en letras": an intertextual approach to the works of Rudolfo A. Anaya

This essay analyzes the value of an intertextual approach to reading the works of Rudolfo A. Anaya. My intention is not to discuss the influence of other writers on Anaya’s works but, rather, the ways in which Anaya makes reference to authors and titles from multiple literary traditions. I explore the different types of intertextual allusions in Anaya’s works to then concentrate on an in-depth analysis of intertextuality in Anaya’s Sonny Baca quartet. I argue that Anaya uses intertextuality to both represent and transcend culture in a way that blurs the differences between the local and the global, the particular and the universal