Balmer Line Variations in the Radio-Loud AGN PG 1512+370

We present spectroscopic observations of the quasar PG~1512+370, covering the Hbeta line spectral range and collected at moderate resolution (2-7 A FWHM) from 1988 to 1996. The observations show that the blue wing of the Hbeta broad profile component has changed significantly in flux and shape between 1988 and 1990 and between 1995 and 1996. A displaced blue peak on the Hbeta profile, visible in 1988, but not in the 1990-1995 spectra, is revealed again in one of the spectra obtained in 1996. The blue peak (in both the 1988 and 1996 spectra) is centered at Delta v_r ~ -3000 +/- 500 km/s from the rest frame defined by the narrow component of Hbeta, and the OIII lambda4959,5007 lines. We discuss several conflicting interpretations of the data. We find that the variability of the Hbeta blue wing is consistent with Balmer line emission from regions whose motion is predominantly radial, if variations of the blue wing are a response to continuum changes. Alternatively, we note that observed Hbeta line profile variations are consistent with a variable line component as in a ``binary black hole'' scenario. More frequent observations of Hbeta are needed to distinguish among these hypotheses.Comment: 19 pages, 1 embedded figure (eps), to appear in ApJ 49

Orbital parameters of supergiant fast X-ray transients

Supergiant fast X-ray transient (SFXT) is a new class of the high mass X-ray binary that shows short X-ray flares. The physical mechanism of SFXT short flares is still open for discussion. The accretion process of dense clumps in stellar wind onto neutron star (NS) has been proposed as the origin of such short flares. In order to examine the applicability of the clumpy wind scenario, we focus on the accretion mode that depends on orbital parameters. Our goal is to impose restrictions on the orbital parameters of SFXT. Assuming a simple analytic model of clumpy wind, we investigate the condition where the size of accretion cylinder overcomes the clump size. The allowed parameter region for SFXT is restricted in a relatively narrow window in $P_{\rm{orb}} - e$ diagram. Binary systems with large eccentricities (e \ga 0.4) and moderate orbital periods ($P_{\rm{orb}} \sim 10$ d) are prone to show periodic X-ray outbursts which are characteristic for SFXT. We confirm that systems with a long orbital period of more than 100 days cannot produce bright X-ray flares in the simple clumpy wind scenario.Comment: 6 pages, accepted for publication in A&

Percutaneous Nephrolithotomy in Children

The surgical management of pediatric stone disease has evolved significantly over the last three decades. Prior to the introduction of shockwave lithotripsy (SWL) in the 1980s, open lithotomy was the lone therapy for children with upper tract calculi. Since then, SWL has been the procedure of choice in most pediatric centers for children with large renal calculi. While other therapies such as percutaneous nephrolithotomy (PNL) were also being advanced around the same time, PNL was generally seen as a suitable therapy in adults because of the concerns for damage in the developing kidney. However, recent advances in endoscopic instrumentation and renal access techniques have led to an increase in its use in the pediatric population, particularly in those children with large upper tract stones. This paper is a review of the literature focusing on the indications, techniques, results, and complications of PNL in children with renal calculi

Spatial averaging and apparent acceleration in inhomogeneous spaces

As an alternative to dark energy that explains the observed acceleration of the universe, it has been suggested that we may be at the center of an inhomogeneous isotropic universe described by a Lemaitre-Tolman-Bondi (LTB) solution of Einstein's field equations. To test this possibility, it is necessary to solve the null geodesics. In this paper we first give a detailed derivation of a fully analytical set of differential equations for the radial null geodesics as functions of the redshift in LTB models. As an application we use these equaions to show that a positive averaged acceleration $a_D$ obtained in LTB models through spatial averaging can be incompatible with cosmological observations. We provide examples of LTB models with positive $a_D$ which fail to reproduce the observed luminosity distance $D_L(z)$. Since the apparent cosmic acceleration $a^{FLRW}$ is obtained from fitting the observed luminosity distance to a FLRW model we conclude that in general a positive $a_D$ in LTB models does not imply a positive $a^{FLRW}$.Comment: 16 pages, 12 figures. Explicit derivation of the fully analytical null geodesic equations has been added. Published in GR

Separaxion anxiety in pediatric migraine without aura: A pilot study

Background: Separation anxiety (SA) can be defined as the fear reaction and protest manifested by children when the main caregivers move away from him/her or in front of unfamiliar person. SA near eight months may be considered as an important and normal phase of the correct and typical social neurodevelopment. Aims of the present pilot study is assessing the prevalence of separation anxiety in a population of patients with migraine without aura (MwA). Materials and methods: 119 children (69 males) suffering from MwA (mean age 1.78 ± 7:59) were consecutively recruited. The control population consisted of 231 (114 males) healthy subjects similar for age (7.64 ± 1:34; p = 0.768) and gender (p=0.987) The Screen for child anxiety related emotional disorders (SCARED) test was used to assess the prevalence of separation anxiety among MwA children. Results: Healthy individuals are on average less affected (mean 4.72 ± 0:32) of the Separation Anxiety Disorder respect of MwA children (mean 6.83 ± 0.97; p < 0.001) (Figure 1). Conclusion. MwA presents many psychiatric comorbidities and among ones separation anxiety may be considered in the clinical and therapeutic management of pediatric primary headache

Environmental Activism of Teacher-Scholars in the Neoliberal University

This article takes a case study approach to examine social justice-oriented environmental activism of faculty in the context of neoliberalism. As an evolving trend, university corporatization places new economic burdens on universities and their students and has contributed to a tenuous landscape for faculty in terms of academic freedom and job security. In particular, we examine a faculty-led response to hydraulic fracturing, or fracking, at the University of Northern Colorado in Greeley, Colorado. Drawing on participant observation, semi-structured interviews, and campus-wide survey data, we document this response as a “tempered grassroots leader-ship” approach to workplace inquiry and activism. We discuss both the opportunities and limitations of promoting more transparent, informed, and inclusive decision-making on campus via internal and tempered activism strategies. Ultimately, this case presents lessons learned regarding social change practices of teacher-scholar-activists on college campuses. These experiences are especially germane in the “Trump era” of top-down and socially regressive decision-making