Elusive AGN in the XMM-Newton bright serendipitous survey

AIMS: We investigate here the nature of all the sources (35 in total) in the XBS survey (which is 86% optically identified) showing an optical spectrum dominated by the light from the host galaxy with no evidence (or little evidence) for the presence of an AGN. METHODS: We use the X-ray spectral analysis to assess the presence of an AGN in these sources and to characterize its properties. RESULTS: We detect AGN activity in 33 out of 35 sources. The remaining 2 sources are the ones with the lowest X-ray luminosity in the sample (L[2-10keV]<10^41 erg s^-1) and their X-ray emission could be produced within the host galaxy. We find that the ``recognition problem'' for AGN is very critical in the low-luminosity regime (at least 60% of the AGN with L[2-10keV]<10^43 erg s^-1 are elusive) becoming negligible for high X-ray luminosities (~1.5% of elusive AGN with L[2-10keV]>10^44 erg s^-1). This problem affects mostly absorbed AGN (~40% of type~2 AGN in the survey are elusive) but also a significant fraction of unabsorbed AGN (8%). CONCLUSIONS: We find that the simplest explanations of why these 33 (or most of them) AGNs are elusive are two: at low X-ray luminosities (<10^43 erg s^-1) the most important reason is the intrinsically low AGN/galaxy contrast (optical dilution) while at high luminosities (>10^44 erg s^-1) it is due to the optical absorption (in the Compton-thin regime, i.e. NH<10^24 cm^-2). Alternative hypotheses, like the presence of Compton-thick sources, BL Lac objects or ``non-standard'' AGN (e.g. with alpha_OX<1 or with weak/absorbed Narrow Line Region) are not supported by the data although we cannot exclude the presence in the sample of a few sources of these types.Comment: accepted for publication in A&A, 17 pages, 9 figure

ESRC IAA Workshop: Towards Maximising International PhD Students' Experience: Extended Summary

No abstract available

“Being in Balance”: Self-Management Experiences Among Young Women with Type 1 Diabetes

Women possess characteristics and experiences unique and different from men. Biological processes such as puberty, menstruation, motherhood and menopause may present challenges to self-management for individuals living with type 1 (T1) diabetes mellitus. In this study, descriptive phenomenology was used to uncover the self-management experiences of nine women aged 22- 30 years living with T1 diabetes. Data collection and analysis occurred simultaneously and followed the methodical structure of van Manen (1997). Study findings revealed five themes: 1) elusiveness of control; 2) dualism of technology; 3) forecasting and maintaining routines; 4) dealing with the “ups and downs”; and, 5) interfacing with the health care team. The essence of the experience for participants revolved around trying to achieve a state of “being in balance.” For these young women, self-management encompassed a desire and need to be in balance with their life and blood sugar levels

\u3ci\u3eFisher v. Grutter\u3c/i\u3e

There is no reason for the Supreme Court to have granted certiorari in Fisher v. University of Texas at Austin. Unless, of course, the Court plans to overrule Grutter v. Bollinger—the case on which the Texas affirmative action plan at issue in Fisher was based. If that is its plan, the Court can invalidate the Texas program on some narrow ground that masks the magnitude of what it is doing. Or it can explicitly overrule Grutter—a case that no longer commands majority support on a Supreme Court whose politics of affirmative action has now been refashioned by personnel changes. The author predicts that the Court will invalidate the Texas plan in a narrow opinion that leaves open the theoretical possibility of some future affirmative action plans surviving constitutional scrutiny. But ironically—as a proponent of racial justice—she hopes that any decision to invalidate the Texas plan expressly overrules Grutter and articulates the Court’s apparent preference for shutting the door on affirmative action completely, rather than disingenuously allowing the light of false hope to seep through a crack in the doorway. If the Supreme Court closes the door, the political process can react directly to the Court’s racial ideology, rather than continuing to be distracted by the Court’s coquettish conception of racial equality. With any luck, this will put the future of affirmative action back in the hands of the political branches—which, of course, is where it belonged to begin with

A Fortiori Logic: Innovations, History and Assessments

A Fortiori Logic: Innovations, History and Assessments is a wide-ranging and in-depth study of a fortiori reasoning, comprising a great many new theoretical insights into such argument, a history of its use and discussion from antiquity to the present day, and critical analyses of the main attempts at its elucidation. Its purpose is nothing less than to lay the foundations for a new branch of logic and greatly develop it; and thus to once and for all dispel the many fallacious ideas circulating regarding the nature of a fortiori reasoning. The work is divided into three parts. The first part, Formalities, presents the author’s largely original theory of a fortiori argument, in all its forms and varieties. Its four (or eight) principal moods are analyzed in great detail and formally validated, and secondary moods are derived from them. A crescendo argument is distinguished from purely a fortiori argument, and similarly analyzed and validated. These argument forms are clearly distinguished from the pro rata and analogical forms of argument. Moreover, we examine the wide range of a fortiori argument; the possibilities of quantifying it; the formal interrelationships of its various moods; and their relationships to syllogistic and analogical reasoning. Although a fortiori argument is shown to be deductive, inductive forms of it are acknowledged and explained. Although a fortiori argument is essentially ontical in character, more specifically logical-epistemic and ethical-legal variants of it are acknowledged. The second part of the work, Ancient and Medieval History, looks into use and discussion of a fortiori argument in Greece and Rome, in the Talmud, among post-Talmudic rabbis, and in Christian, Moslem, Chinese and Indian sources. Aristotle’s approach to a fortiori argument is described and evaluated. There is a thorough analysis of the Mishnaic qal vachomer argument, and a reassessment of the dayo principle relating to it, as well as of the Gemara’s later take on these topics. The valuable contribution, much later, by Moshe Chaim Luzzatto is duly acknowledged. Lists are drawn up of the use of a fortiori argument in the Jewish Bible, the Mishna, the works of Plato and Aristotle, the Christian Bible and the Koran; and the specific moods used are identified. Moreover, there is a pilot study of the use of a fortiori argument in the Gemara, with reference to Rodkinson’s partial edition of the Babylonian Talmud, setting detailed methodological guidelines for a fuller study. There is also a novel, detailed study of logic in general in the Torah. The third part of the present work, Modern and Contemporary Authors, describes and evaluates the work of numerous (some thirty) recent contributors to a fortiori logic, as well as the articles on the subject in certain lexicons. Here, we discover that whereas a few authors in the last century or so made some significant contributions to the field, most of them shot woefully off-target in various ways. The work of each author, whether famous or unknown, is examined in detail in a dedicated chapter, or at least in a section; and his ideas on the subject are carefully weighed. The variety of theories that have been proposed is impressive, and stands witness to the complexity and elusiveness of the subject, and to the crying need for the present critical and integrative study. But whatever the intrinsic value of each work, it must be realized that even errors and lacunae are interesting because they teach us how not to proceed. This book also contains, in a final appendix, some valuable contributions to general logic, including new analyses of symbolization and axiomatization, existential import, the tetralemma, the Liar paradox and the Russell paradox

Boston University Symphony Orchestra, October 28, 2014

This is the concert program of the Boston University Symphony Orchestra performance on Tuesday, October 28, 2014 at 8:00 p.m., at the Tsai Performance Center, 685 Commonwealth Avenue, Boston, Massachusetts. Works performed were A Pastoral Symphony (Symphony No. 3) by Ralph Vaughan Williams, High Bridge - Prelude for Orchestra by Charles Fussell, and Ibéria (Images II) by Claude Debussy. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund

Corpus Analysis and Lexical Pragmatics: An Overview

Lexical pragmatics studies the processes by which lexically encoded meanings are modified in use; well-studied examples include lexical narrowing, approximation and metaphorical extension. Relevance theorists have been trying to develop a unitary account on which narrowing, approximation and metaphorical extension are all explained in the same way. While there have been several corpus-based studies of metaphor and a few of hyperbole or approximation, there has been no attempt so far to test the unitary account using corpus data. This paper reports the results of a corpus-based investigation of lexical-pragmatic processes, and discusses the theoretical issues and challenges it raises