Factors affecting learning of Mexican primary school children

This paper isolates factors affecting Mexican primary school children's grade repetition rates and their educational outcomes, as measured by reading and math scores on a standardized test. We estimate an econometric production function for primary school education where the endogenous variables are language achievement, math achievement and grade repetition for individual children. The empirical results indicate that gender, socioeconomic status, parental education levels and past repetition of a grade are significant and common determinants of the endogenous variables. This study also shows that more teaching hours and increased student-teacher interaction, coupled with improved facilities and libraries, improve children's math and language achievement scores. Policy implications flowing from these results are outlined.

Rotational Instabilities and Centrifugal Hangup

One interesting class of gravitational radiation sources includes rapidly rotating astrophysical objects that encounter dynamical instabilities. We have carried out a set of simulations of rotationally induced instabilities in differentially rotating polytropes. An $n$=1.5 polytrope with the Maclaurin rotation law will encounter the $m$=2 bar instability at $T/|W| \gtrsim 0.27$. Our results indicate that the remnant of this instability is a persistent bar-like structure that emits a long-lived gravitational radiation signal. Furthermore, dynamical instability is shown to occur in $n$=3.33 polytropes with the $j$-constant rotation law at $T/|W| \gtrsim 0.14$. In this case, the dominant mode of instability is $m$=1. Such instability may allow a centrifugally-hung core to begin collapsing to neutron star densities on a dynamical timescale. If it occurs in a supermassive star, it may produce gravitational radiation detectable by LISA.Comment: 13 pages (includes 11 figures) and 1 separate jpeg figure; to appear in Astrophysical Sources of Gravitational Radiation, AIP conference proceedings, edited by Joan M. Centrell

Assessing Student Exposure to and Use of Computer Technologies through an Examination of Course Syllabi

A syllabus analysis instrument was developed to assist program evaluators, administrators and faculty in the identification of skills that students use as they complete their college coursework. While this instrument can be tailored for use with a variety of learning domains, we used it to assess students\u27 use of and exposure to computer technology skills. The reliability and validity of the instrument was examined through an analysis of 88 syllabi from courses within the teacher education program and the core curriculum at a private Midwest US university. Results indicate that the instrument has good inter‐rater reliability and ratings by and interviews with faculty and students provide evidence of construct validity. The use and limitations of the instrument in educational program evaluation are discussed

Positioning with stationary emitters in a two-dimensional space-time

The basic elements of the relativistic positioning systems in a two-dimensional space-time have been introduced in a previous work [Phys. Rev. D {\bf 73}, 084017 (2006)] where geodesic positioning systems, constituted by two geodesic emitters, have been considered in a flat space-time. Here, we want to show in what precise senses positioning systems allow to make {\em relativistic gravimetry}. For this purpose, we consider stationary positioning systems, constituted by two uniformly accelerated emitters separated by a constant distance, in two different situations: absence of gravitational field (Minkowski plane) and presence of a gravitational mass (Schwarzschild plane). The physical coordinate system constituted by the electromagnetic signals broadcasting the proper time of the emitters are the so called {\em emission coordinates}, and we show that, in such emission coordinates, the trajectories of the emitters in both situations, absence and presence of a gravitational field, are identical. The interesting point is that, in spite of this fact, particular additional information on the system or on the user allows not only to distinguish both space-times, but also to complete the dynamical description of emitters and user and even to measure the mass of the gravitational field. The precise information under which these dynamical and gravimetric results may be obtained is carefully pointed out.Comment: 14 pages; 5 figure

Bioinorganic Chemistry

This book covers material that could be included in a one-quarter or one-semester course in bioinorganic chemistry for graduate students and advanced undergraduate students in chemistry or biochemistry. We believe that such a course should provide students with the background required to follow the research literature in the field. The topics were chosen to represent those areas of bioinorganic chemistry that are mature enough for textbook presentation. Although each chapter presents material at a more advanced level than that of bioinorganic textbooks published previously, the chapters are not specialized review articles. What we have attempted to do in each chapter is to teach the underlying principles of bioinorganic chemistry as well as outlining the state of knowledge in selected areas. We have chosen not to include abbreviated summaries of the inorganic chemistry, biochemistry, and spectroscopy that students may need as background in order to master the material presented. We instead assume that the instructor using this book will assign reading from relevant sources that is appropriate to the background of the students taking the course. For the convenience of the instructors, students, and other readers of this book, we have included an appendix that lists references to reviews of the research literature that we have found to be particularly useful in our courses on bioinorganic chemistry

The Intermediate Mass Black Hole Candidate in the Center of NGC 404: New Evidence from Radio Continuum Observations

We present the results of deep, high-resolution, 5 GHz Expanded Very Large Array (EVLA) observations of the nearby, dwarf lenticular galaxy and intermediate mass black hole candidate (M ~4.5 x 10^5 M_sun), NGC 404. For the first time, radio emission at frequencies above 1.4 GHz has been detected in this galaxy. We found a modestly resolved source in the NGC 404 nucleus with a total radio luminosity of 7.6 +/- 0.7 x 10^17 W/Hz at 5 GHz and a spectral index from 5 to 7.45 GHz of alpha = -0.88 +/- 0.30. NGC 404 is only the third central intermediate mass black hole candidate detected in the radio regime with subarcsecond resolution. The position of the radio source is consistent with the optical center of the galaxy and the location of a known, hard X-ray point source (Lx ~1.2 x 10^37 erg/s). The faint radio and X-ray emission could conceivably be produced by an X-ray binary, star formation, a supernova remnant or a low-luminosity AGN powered by an intermediate mass black hole. In light of our new EVLA observations, we find that the most likely scenario is an accreting intermediate mass black hole, with other explanations incompatible with the observed X-ray and/or radio luminosities or statistically unlikely.Comment: Accepted for publication to Ap

Fighter Experience in All Quiet in the Western Front - 1929 by Erich Maria Remarque

Estudio de la novela de E. M. Remarque im westen nichts neues, fina descripción de sus experiencias como soldado en la gran guerra, que por su veracidad y profundo humanismo de gran calado ético y autocrítico se ha convertido en texto de referencia de lasStudy E. M. Remarque s novel all quiet in the Western front, fine description of his experiences as a soldier in the great war, which for its accuracy and deep humanism of great ethical and self-criticism has become a reference text of the war experience