The Optical/Near-IR Colors of Broad Absorption Line Quasars, Including the Candidate Radio-Loud BAL Quasar 1556+3517

A candidate radio-loud broad absorption line quasar (RLBAL) has been reported by Becker et al. (1997). We present JHK observations of this object and three other radio-detected BALs taken with the new Michigan-Dartmouth-MIT/Ohio State/Aladdin IR Camera (MOSAIC) on the KPNO 4-meter. The candidate RLBAL 1556+3517 has B-K=6.63, redder than all but one or two known z>1 quasars. This strongly suggests the observed continuum of this quasar is reddened by dust. Even when this extreme reddening is taken into account 1556+3517 is still probably radio-loud, although near-IR spectroscopy to measure its Balmer decrement will be needed to verify this. In addition, since it is a flat-spectrum object, VLBI observations to determine the extent (if any) to which beaming affects our estimate of its radio luminosity will be needed before 1556+3517 can be unequivocally declared a radio-loud BAL. We also use our data and data from the literature to show that optically selected BALs as a class have B-K colors consistent with the observed distribution for optically selected quasars as a whole. Thus there is currently no evidence that the tendency of optically selected BALs to be preferentially radio-intermediate (Hooper, Francis, & Impey 1993) is due to extinction artificially lowering estimated BAL optical luminosities. However, as most quasar surveys, both radio and optical, would be insensitive to a population of reddened radio-quiet BALs, the existence of a large population of reddened BALs similar to 1556+3517 cannot yet be ruled out.Comment: Accepted to ApJ Letters; 10 pages including 1 figure and 2 tables. This version somewhat revised from initial submission, with a better figur

Axial Symmetry and Rotation in the SiO Maser Shell of IK Tauri

We observed v=1, J=1-0 43-GHz SiO maser emission toward the Mira variable IK Tauri (IK Tau) using the Very Long Baseline Array (VLBA). The images resulting from these observations show that SiO masers form a highly elliptical ring of emission approximately 58 x 32 mas with an axial ratio of 1.8:1. The major axis of this elliptical distribution is oriented at position angle of ~59 deg. The line-of-sight velocity structure of the SiO masers has an apparent axis of symmetry consistent with the elongation axis of the maser distribution. Relative to the assumed stellar velocity of 35 km/s, the blue- and red-shifted masers were found to lie to the northwest and southeast of this symmetry axis respectively. This velocity structure suggests a NW-SE rotation of the SiO maser shell with an equatorial velocity, which we determine to be ~3.6 km/s. Such a NW-SE rotation is in agreement with a circumstellar envelope geometry invoked to explain previous water and OH maser observations. In this geometry, water and OH masers are preferentially created in a region of enhanced density along the NE-SW equator orthogonal to the rotation/polar axis suggested by the SiO maser velocities.Comment: 17 Pages, 4 figures (2 color); accepted for publication in Ap

A Three Micron Survey of the Chamaeleon I Dark Cloud

We describe an L-band photometric survey of 0.5 square deg of the Cha I dark cloud. The survey has a completeness limit of L < 11.0. Our survey detects 124 sources, including all known pre-main sequence stars with L < 11. The fraction of sources with near-IR excess emission is 58% +- 4% for K = 9-11. Cha I sources have bluer H-K and K-L colors than pre-main sequence stars in Taurus-Auriga. These sources also have a strong correlation between EW(H-alpha) and K-L. Stars with K-L 0.6 have strong H-alpha emission. Because many Cha I sources are heavily reddened, this division between weak emission T Tauri stars and classical T Tauri stars occurs at a redder K-L than in Taurus-Auriga.Comment: 12 pages of text, 4 figures, and 1 three page table of data modified version adds reference and acknowledgemen

The Voices of History: theorising the interpersonal semantics of historical discourses

‘The individual consumer, the learner of history, is offered an impressive array of discursive products geared to catch his or her attention, to persuade him or her of the truth of whatever message is transmitted’ (Blanco and Rosa 1997: 197. In this article I examine these discursive products from the perspective of ‘voice’. I do this as a way of bringing to conscious attention the strategies that historians use in order to persuade and position the ‘consumer’. ‘Voice’ in recent systemic linguistic theorizing refers to distinctive configurations of APPRAISAL choices. Within the domain of history, research to date has identified three main configurations or voices—‘recorder’, ‘interpreter’, and ‘adjudicator’. Central to the research reported on in this article is Martin’s APPRAISAL framework (Martin 1997, 2000). APPRAISAL 1 systems are the semantic resources used to negotiate emotions, judgments, and valuations. In this article I will examine how choices from these systems vary in ways that are systematic — different history texts speak with different ‘voices’. These voices, I argue, are a key rhetorical strategy in history discourse. Different combinations of APPRAISAL resources are drawn on to negotiate the heteroglossic positions of their audiences. As such they are a key resource for both the professional and apprentice historian in their assessment of interpretations of the past

An Explicit Framework for Interaction Nets

Interaction nets are a graphical formalism inspired by Linear Logic proof-nets often used for studying higher order rewriting e.g. \Beta-reduction. Traditional presentations of interaction nets are based on graph theory and rely on elementary properties of graph theory. We give here a more explicit presentation based on notions borrowed from Girard's Geometry of Interaction: interaction nets are presented as partial permutations and a composition of nets, the gluing, is derived from the execution formula. We then define contexts and reduction as the context closure of rules. We prove strong confluence of the reduction within our framework and show how interaction nets can be viewed as the quotient of some generalized proof-nets

Factor structure of the shortened six-item version of the de Jong Gierveld Loneliness Scale (DJGLS-6) : A systematic review and testing factor models in a nationally representative sample

Introduction: Loneliness is linked to negative physical and mental health outcomes. Therefore, it is important to employ reliable and valid screening measures for early detection and treatment. A widely used scale for assessing loneliness is the shortened six-item Jong Gierveld Loneliness Scale (DJGLS-6). Aims: To review and evaluate the factor structure of the DJGLS-6. Methods: Study 1 was a systematic review. To examine the factor structure of the DJGLS-6, peer-reviewed studies were reviewed in accordance with PRISMA guidelines. Study 2 tested the factor analytic models found in Study 1. Confirmatory factor analysis (CFA) was performed using data from a nationally representative sample of adults to assess the latent structure of the six-item scale. Results: In Study 1, findings from the two papers reviewed suggested that the scale measures two correlated dimensions: social and emotional loneliness. This finding was consistent with the results of Study 2. However, the fit statistics for the one and two-factor CFA models were not acceptable. Modification indices indicated that adding a cross-factor loading to allow item 2 (“I miss having people around”) of the social loneliness factor, to load on both the emotional and social factor, to load on both the emotional and social factors would significantly improve the fit of the model. Conclusions: The analysis failed to support previous findings concerning the robustness of the subscales. We recommend performing future evaluations of the scale and for the authors to consider changing item 2 accordingly

A homotopy approach to the feedback stabilization of linear systems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76174/1/AIAA-20236-533.pd

Testing the Blazar Paradigm: ASCA Observations of FSRQs with Steep Soft X-ray Spectra

We present the first observations at medium-hard X-rays with ASCA in 1998 August--November of four Flat Spectrum Radio Quasars (FSRQs), characterized by unusually steep soft X-ray spectra (photon index, \Gamma_{0.2-2.4 keV} \sim 2-2.5), as previously measured with ROSAT. Such steep X-ray slopes are similar to those observed in synchrotron-dominated BL Lacs and are unexpected in the context of the recent blazar paradigm, where sources with strong emission lines (such as FSRQs) are dominated in soft X-rays by a flat inverse Compton tail. We find that the ASCA spectra of the four FSRQs are consistent with a power law model with \Gamma_{2-10 keV} \sim 1.8, flatter than their ROSAT spectra. This indicates the onset of an inverse Compton component at energies \gtrsim 2 keV, in agreement with the blazar unification scheme. However, these objects are still anomalous within the blazar class for their steep soft X-ray continua which, together with non-simultaneous data at longer wavelengths, hint at the possibility that the synchrotron emission extends to soft X-rays. This would imply an anomalously high synchotron peak frequency for a quasar with luminous broad lines, challenging current blazar unification schemes. Alternatively, a plausible explanation for the steep optical-to-soft X-ray continua of the four FSRQs is thermal emission from the accretion disk, similar to the blazars 3C~273 and 3C~345. In the Appendix, we present fits to the SIS data in an effort to contribute to the ongoing calibration of the the time-dependence of the SIS response at low energies.Comment: accepted for publication in The Astrophysical Journa

Urinary Glyphosate Concentrations Among Pregnant Participants in a Randomized, Crossover Trial of Organic and Conventional Diets

Background: Consumption of an organic diet reduces exposure to a range of agricultural pesticides. Only three studies have examined the effect of an organic diet intervention on exposure to the herbicide glyphosate, the most heavily used agricultural chemical in the world. Despite its widespread use, the primary sources of glyphosate exposure in humans are poorly understood. Objective: Our objective was to examine the effect of an organic diet intervention on urinary glyphosate concentrations among pregnant individuals. Methods: We conducted a 2-wk randomized crossover trial in which 39 pregnant participants living near (≤ 0.5 km) or far (\u3e 0.5 km) from agricultural fields received a 1-wk supply of conventional groceries and 1 wk of organic groceries, randomized to order. We collected daily first morning void urine samples and analyzed composite samples from each week for glyphosate. We examined differences in urinary glyphosate concentrations between the conventional week and the organic week among all participants and stratified by residential proximity to an agricultural field. Results: Median specific gravity–adjusted glyphosate concentrations were 0.19 microgram per liter 0.19 μg/L and 0.16 μg/L during the conventional and organic weeks, respectively. We observed modest decreases in urinary glyphosate concentrations from the conventional to organic week among far-field participants, but no difference among near-field participants. In secondary analyses excluding participants who did not meet a priori criteria of compliance with the intervention, we observed significant decreases in urinary glyphosate concentrations, particularly among far-field participants (p \u3c 0.01–0.02, depending on exclusion criteria). Discussion: This trial is the first to examine the effect of an organic diet intervention on glyphosate among people living near and far from agricultural fields. Our results suggest that diet is an important contributor to glyphosate exposure in people living \u3c 0.5 km from agricultural fields; for people living near crops, agriculture may be a dominant exposure source during the pesticide spray season