Quantum Layers over Surfaces Ruled Outside a Compact Set

In this paper, we proved the quantum layer over a surface which is ruled outside a compact set, asymptotically flat but not totally geodesic admits ground states

REASSURE: A Self-contained Mechanism for Healing Software Using Rescue Points

Software errors are frequently responsible for the limited availability of Internet Services, loss of data, and many security compromises. Self-healing using rescue points (RPs) is a mechanism that can be used to recover software from unforeseen errors until a more permanent remedy, like a patch or update, is available. We present REASSURE, a self-contained mechanism for recovering from such errors using RPs. Essentially, RPs are existing code locations that handle certain anticipated errors in the target application, usually by returning an error code. REASSURE enables the use of these locations to also handle unexpected faults. This is achieved by rolling back execution to a RP when a fault occurs, returning a valid error code, and enabling the application to gracefully handle the unexpected error itself. REASSURE can be applied on already running applications, while disabling and removing it is equally facile. We tested REASSURE with various applications, including the MySQL and Apache servers, and show that it allows them to successfully recover from errors, while incurring moderate overhead between 1% and 115%. We also show that even under very adverse conditions, like their continuous bombardment with errors, REASSURE protected applications remain operational

Photoproduction of the ω\omega meson on the proton at large momentum transfer

The differential cross section, $d\sigma/dt$ for $\omega$ meson exclusive photoproduction on the proton above the resonance region ($2.6<W<2.9$ GeV) was measured up to a momentum transfer $-t = 5$ GeV$^2$ using the CLAS detector at Jefferson Laboratory. The $\omega$ channel was identified by detecting a proton and $\pi^+$ in the final state and using the missing mass technique. While the low momentum transfer region shows the typical diffractive pattern expected from Pomeron and Reggeon exchange, at large $-t$ the differential cross section has a flat behavior. This feature can be explained by introducing quark interchange processes in addition to the QCD-inspired two-gluon exchange.Comment: 5 pages, 5 figure

The Keck/OSIRIS Nearby AGN Survey (KONA) I. The Nuclear K-band Properties of Nearby AGN

We introduce the Keck Osiris Nearby AGN survey (KONA), a new adaptive optics-assisted integral-field spectroscopic survey of Seyfert galaxies. KONA permits at ~0.1" resolution a detailed study of the nuclear kinematic structure of gas and stars in a representative sample of 40 local bona fide active galactic nucleus (AGN). KONA seeks to characterize the physical processes responsible for the coevolution of supermassive black holes and galaxies, principally inflows and outflows. With these IFU data of the nuclear regions of 40 Seyfert galaxies, the KONA survey will be able to study, for the first time, a number of key topics with meaningful statistics. In this paper we study the nuclear K-band properties of nearby AGN. We find that the luminosities of the unresolved Seyfert 1 sources at 2.1 microns are correlated with the hard X-ray luminosities, implying that the majority of the emission is non-stellar. The best-fit correlation is logLK = 0.9logL2-10 keV + 4 over 3 orders of magnitude in both K-band and X-ray luminosities. We find no strong correlation between 2.1 microns luminosity and hard X-ray luminosity for the Seyfert 2 galaxies. The spatial extent and spectral slope of the Seyfert 2 galaxies indicate the presence of nuclear star formation and attenuating material (gas and dust), which in some cases is compact and in some galaxies extended. We detect coronal-line emission in 36 galaxies and for the first time in five galaxies. Finally, we find 4/20 galaxies that are optically classified as Seyfert 2 show broad emission lines in the near-IR, and one galaxy (NGC 7465) shows evidence of a double nucleus.Comment: Accepted for publication in ApJ, 19 pages with 18 figure

Temperatures of continuously operated mobile x-ray focal spots

We use the adjective "mobile" to describe a focal spot in an x‐ray tube which moves cyclically in a closed path relative to the target surface on which it is generated quite without reference to whether the spot be fixed or in motion with respect to the tube. Alex Müller and also A. Bouwers have made calculations of the thermal effects in such spots energized for very short fractions of one cycle of motion. This paper treats the case where the focal spot is energized continuously so that a "steady" state of thermal oscillation is set up. The solutions obtained refer only to conditions after this steady state of oscillation is reached. Only the ideal case of a spot of uniform intensity with sharp boundaries is treated. For simplicity the flow of heat from front target surface to cooling water is assumed one dimensional and normal to the front surface over an everywhere uniform thickness d. Curves are plotted showing the ratio of temperature rise in moving spots to that in fixed spots of the same size as a function of r the size of the spot relative to the length of path it describes and of θ a variable depending on the speed of rotation, the thickness d and the thermal constants of the target material. Curves of the ratio of permissible energy input for moving and fixed spots, respectively, as a function of the aforementioned variables are also shown. The paper gives a solution reduced to figures and curves of the heat flow equation for certain boundary conditions which to the author's knowledge has never before been obtained and therefore has some interest beyond its immediate application to x‐ray tubes. Certain mathematical difficulties of practical interest are also overcome in a way which may be helpful in other problems of similar nature. For the reader uninterested in mathematics the results are independently discussed in a separate section. Approximate methods are given for applying the results of the paper to targets consisting of two materials such as tungsten and copper

A z=0.9 supercluster of X-ray luminous, optically-selected, massive galaxy clusters

We report the discovery of a compact supercluster structure at z=0.9. The structure comprises three optically-selected clusters, all of which are detected in X-rays and spectroscopically confirmed to lie at the same redshift. The Chandra X-ray temperatures imply individual masses of ~5x10^14 Msun. The X-ray masses are consistent with those inferred from optical--X-ray scaling relations established at lower redshift. A strongly-lensed z~4 Lyman break galaxy behind one of the clusters allows a strong-lensing mass to be estimated for this cluster, which is in good agreement with the X-ray measurement. Optical spectroscopy of this cluster gives a dynamical mass in good agreement with the other independent mass estimates. The three components of the RCS2319+00 supercluster are separated from their nearest neighbor by a mere <3 Mpc in the plane of the sky and likely <10 Mpc along the line-of-sight, and we interpret this structure as the high-redshift antecedent of massive (~10^15 Msun) z~0.5 clusters such as MS0451.5-0305.Comment: ApJ Letters accepted. 5 pages in emulateapj, 3 figure

Design and Implementation of a Python-Based Active Network Platform for Network Management and Control

Active networks can provide lightweight solutions for network management-related tasks. Specific requirements for these tasks have to be met, while at the same time several issues crucial for active networks can be solved rather easily. A system addressing especially network management was developed and implemented. It provides a flexible environment for rapid development using the platform-independent programming language Python, and also supports platform dependent native code. By allowing to add new functions to network devices it improves the performance of Internet routers, and simplifies the introduction and maintenance of new services