An X-ray View of Radio Sources

We review recent examples where the synergy between radio and X-ray observations has led to substantial progress in understanding astronomical systems. The sub-arcsecond imaging capabilities of the Chandra X-ray observatory provides a 100-fold improvement for comparing X-ray and radio structures. We specifically discuss examples which provide insight into the outflow of material and energy from pulsars and supernovae, the centers of clusters of galaxies, and the nuclei of quasars.Comment: 17 pages, 13 figures. Talk presented at the JENAM-2003 Symposium, "Radio Astronomy at 70: from Karl Jansky to microjansky," Budapest, Hungary, 27-30 August 2003. To be published by EDP Sciences, eds. L. Gurvits, S. Frey, and S. Rawling

Scientific investigations with the data base HEAO-1 scanning modulator collimator

The hardware specification for the Scanning Modulation Collimator (MC) experiment on HEAO-1 was to measure positions of bright (greater than 10(exp -11) ergs/cm(exp 2)s), hard (1 to 15 keV) x-ray sources to 5-10 arcsec, and to measure their size and structure in three energy bands down to 10 arcsec resolution. The scientific purpose of this specification was to enable the identification of these x-ray sources with optical and radio objects in order to elucidate the x-ray emission mechanism and the nature of the candidate astronomical system. The experiment was an outstanding success. Hardware systems functioned perfectly although loss of one (out of eight) proportional counters degraded our sensitivity by about 10 percent. Our aspect solution of 7 arcsec precision, allowed us to achieve statistic-limited location precision for all but the strongest sources. We vigorously pursued a strategy of determining the scientific importance of each identification, and of publishing each scientific result as it came along

EX56a study of extended X-ray emission around isolated galaxies EX56b identification and spectra of bright X-ray sources at high galactic latitude

The EXOSAT observations confirmed the identification and extended nature of PKS 2345-35. It gave a good 2 to 10 keV X-ray spectrum and a detailed spatial profile indicating asymmetry of the structure. In the high galactic latitidue investigation, the BL Lac object identified with the HEAO-1 source 1430+423 was detected, and the first X-ray spectrum was obtained. Several simulataneous observations of H0323+022 were obtained over a broad range of electromagnetic spectrum. Studies of luminous active galactic nuclei have given significant information on the spectrum of the quasar PKS 0558-504. In a study of Southern sky cataclysmic variables, the EXOSAT was used to determine the X-ray spectrum and search for periodicities in two objects. Studies of complete identifications have revealed that X-ray sources in two high galactic latitude fields are stars, and therefore are to be excluded from the Piccinotti extragalactic sample. Only one Piccinotti source remains to be identified

From manuscript catalogues to a handbook of Syriac literature: Modeling an infrastructure for Syriaca.org

Despite increasing interest in Syriac studies and growing digital availability of Syriac texts, there is currently no up-to-date infrastructure for discovering, identifying, classifying, and referencing works of Syriac literature. The standard reference work (Baumstark's Geschichte) is over ninety years old, and the perhaps 20,000 Syriac manuscripts extant worldwide can be accessed only through disparate catalogues and databases. The present article proposes a tentative data model for Syriaca.org's New Handbook of Syriac Literature, an open-access digital publication that will serve as both an authority file for Syriac works and a guide to accessing their manuscript representations, editions, and translations. The authors hope that by publishing a draft data model they can receive feedback and incorporate suggestions into the next stage of the project.Comment: Part of special issue: Computer-Aided Processing of Intertextuality in Ancient Languages. 15 pages, 4 figure

A Chandra Search for X-Ray Jets in Redshift 6 Quasars

We have searched for X-ray jets in the recent Chandra observations of three Sloan Digital Sky Survey (SDSS) quasars at redshift z ~ 6. All 3 quasars were detected in X-rays in these relatively short observations. SDSS 1030+0524 is not consistent with a point source, and may be a gravitationally lensed system. We find a possible jet-like feature 23" from the quasar SDSS 1306+0356. We can explain the emission by inverse Compton scattering off the Cosmic Microwave Background, assuming that the intrinsic properties of the system are similar to other X-ray jets at z<1. Deeper observations to confirm the interpretation as a jet will be practical.Comment: Revised probabilities of X-ray detections, established 1030+0524 as extended and suggested gravitational lensing. Version accepted by ApJ Letter

Shutting the Black Door: Using American Needle to Cure the Problem of Improper Product Definition

Section 1 of the Sherman Act is designed to protect competition by making illegal any agreement that has the effect of limiting consumer choice. To make this determination, courts first define the product at issue and then consider the challenged restraint\u27s impact on the market in which that product competes. When considering § 1 allegations against sports leagues, courts have tended to define products according to the structure of the leagues. The result of this tendency is that harm to competition between the leagues\u27 teams is not properly accounted for in the courts\u27 analyses. This, in turn, grants leagues a form of immunity to which they are not entitled under any statutory or doctrinal rule. In reaching this conclusion, this Note reviews the business structure of sports leagues and explains why they present such a difficult challenge for courts. It then examines a number of cases in which courts, struggling with those challenges, improperly defined the product according to league structure. For each case, the Note explains the mistake that was made and how that mistake granted leagues de facto immunity. This Note concludes by arguing that the Supreme Court\u27s recent decision in American Needle can serve as the impetus for correcting this mistake if courts broadly interpret the meaning of the case by looking to the logic that animates it

Shutting the Black Door: Using American Needle to Cure the Problem of Improper Product Definition

Section 1 of the Sherman Act is designed to protect competition by making illegal any agreement that has the effect of limiting consumer choice. To make this determination, courts first define the product at issue and then consider the challenged restraint\u27s impact on the market in which that product competes. When considering § 1 allegations against sports leagues, courts have tended to define products according to the structure of the leagues. The result of this tendency is that harm to competition between the leagues\u27 teams is not properly accounted for in the courts\u27 analyses. This, in turn, grants leagues a form of immunity to which they are not entitled under any statutory or doctrinal rule. In reaching this conclusion, this Note reviews the business structure of sports leagues and explains why they present such a difficult challenge for courts. It then examines a number of cases in which courts, struggling with those challenges, improperly defined the product according to league structure. For each case, the Note explains the mistake that was made and how that mistake granted leagues de facto immunity. This Note concludes by arguing that the Supreme Court\u27s recent decision in American Needle can serve as the impetus for correcting this mistake if courts broadly interpret the meaning of the case by looking to the logic that animates it

Lessons from the endothelial junctional mechanosensory complex

Mechanotransduction plays a key role in both normal physiology and in diseases such as cancer, atherosclerosis and hypertension. Nowhere is this more evident than in the vascular system, where fluid shear stress from blood flow plays a critical role in shaping the blood vessels and in determining their function and dysfunction. Responses to flow are mediated in part by a complex of proteins comprised of PECAM-1, VE-cadherin and VEGFR2 at endothelial cell-cell junctions; all proteins that clearly have other, non-mechanical functions. We review recent progress toward understanding the functions and mechanisms of mechanotransduction by this complex and suggest some principles that may apply more broadly