The QSO evolution derived from the HBQS and other complete QSO surveys

An ESO Key programme dedicated to an Homogeneous Bright QSO Survey (HBQS) has been completed. 327 QSOs (Mb<-23, 0.3<z<2.2) have been selected over 555 deg^2 with 15<B<18.75. For B<16.4 the QSO surface density turns out to be a factor 2.2 higher than what measured by the PG survey, corresponding to a surface density of 0.013+/-.006 deg^{-2}. If the Edinburgh QSO Survey is included, an overdensity of a factor 2.5 is observed, corresponding to a density of 0.016+/-0.005 deg^{-2}. In order to derive the QSO optical luminosity function (LF) we used Monte Carlo simulations that take into account of the selection criteria, photometric errors and QSO spectral slope distribution. The LF can be represented with a Pure Luminosity Evolution (L(z)\propto(1+z)^k) of a two power law both for q_0=0.5 and q_0=0.1. For q_0=0.5 k=3.26, slower than the previous Boyle's (1992) estimations of k=3.45. A flatter slope beta=-3.72 of the bright part of the LF is also required. The observed overdensity of bright QSOs is concentrated at z<0.6. It results that in the range 0.3<z<0.6 the luminosity function is flatter than observed at higher redshifts. In this redshift range, for Mb<-25, 32 QSOs are observed instead of 19 expected from our best-fit PLE model. This feature requires a luminosity dependent luminosity evolution in order to satisfactorily represent the data in the whole 0.3<z<2.2 interval.Comment: Invited talk in "Wide Field Spectroscopy" (20-24 May 1996, Athens), eds. M. Kontizas et al. 6 pages and 3 eps figures, LaTex file, uses epfs.sty and crckapb.sty (included

Megaschallunterstützter Stofftransport in LIGA-Mikrostrukturen

Die Herstellung von hohen Strukturen mit hohem Aspektverhältnis ist eine aktuelle Aufgabe der LIGA-Technologie. Um die Prozessdauer der nasschemischen Prozessschritte wie Entwicklung und Galvanoformung zu minimieren und die hohe Qualität der Mikrostrukturen zu gewährleisten, sollten die Stofftransportbedingungen untersucht und optimiert werden. Ziel dieser Arbeit ist, den Wirkmechanismus des Megaschalls auf den Stofftransport vor allem in LIGA-Mikrostrukturen mit hohem Aspektverhältnis experimentell aufzuklären. Als Untersuchungsmethode wurde die elektrochemische Grenzstrommethode ausgewählt. Diese Methode zeichnet sich durch die Möglichkeit einer direkten Messung der Stofftransportrate in situ aus. Für die praktische Umsetzung dieser Methode unter Megaschallbedingungen wurde eine neue Megaschallzelle konzipiert und aufgebaut. Für die Untersuchung der Stofftransportprozesse in Mikrostrukturen dienten rotierende zurückgesetzte Mikrostrukturelektroden (RMEs). In dieser Arbeit wurden erstmals LIGA-Mikrostrukturen in die rotierenden Mikrostrukturelektroden eingesetzt. Für die Herstellung dieser Arbeitselektroden wurde eine LIGA-basierte Technik ausgearbeitet. Im experimentellen Teil dieser Arbeit wurden die möglichen Einflussparameter wie die Position der Probe im Schallfeld, die elektrische Leistung der Schallquelle und die Geometrie der Mikrostrukturen, variiert und der Grenzstrom als Maß für die Stofftransportrate aufgenommen. Als Ergebnis der durchgeführten Experimente wurden folgende Zusammenhänge festgestellt: • Die Positionierung der Probe bezüglich der Schallquelle hat einen wesentlichen Einfluss auf die Stofftransportrate. Es besteht eine Korrelation zwischen den räumlichen Schalldruck- und Grenzstromverteilungen. • Die Stofftransportrate hängt von der elektrischen Leistung der Megaschallquelle ab. Die Form dieser Abhängigkeit ist für die unterschiedlichen Strukturgeometrien unterschiedlich. • Die Beschallung ruft eine lokale Erwärmung innerhalb der Mikrostrukturen hervor. • Der Grad der gesamten Verbesserung des Stofftransportes hängt unter anderem von der Geometrie der Mikrostrukturen und deren Zusammensetzung ab. Diese Ergebnisse werden im Folgenden mit Ergebnissen aus der Literatur verglichen und daraus ein Modell zum Wirkmechanismus des Megaschalls abgeleitet. Die Stofftransportrate bei megaschallunterstützten Prozessen in Mikrostrukturen wird durch zwei Effekte beeinflusst, durch die lokale Erwärmung und durch die Ausbildung der akustischen Mikroströmungen innerhalb der Strukturen. Der thermische Effekt trägt für alle Strukturtypen bei, während der Beitrag des hydrodynamischen Effektes stark von der Strukturgeometrie abhängt. Durch den thermischen Effekt ist die Vergrößerung der Stofftransportrate um bis zu 30 % möglich. Die Größe dieses Beitrages hängt von der Resisthöhe ab. Der hydrodynamische Effekt kann eine Zunahme der Stofftransportrate um ein Mehrfaches hervorrufen

A cross sectional study on prescription pattern of drugs in upper respiratory tract infections in a tertiary care hospital

Background: Upper respiratory tract infections are one of the leading causes of hospital visits worldwide. Judicious use of antibiotics is challenging for upper respiratory tract infections (URTIs) in developing countries like India. This leads to inappropriate use of antibiotics causing many dreaded conditions like antibacterial resistance among other things. Hence rational use of drugs, mainly antibacterial, is a priority to reduce the burden of treatment failure. The objective of this study is to study the prescribing patterns and rationality of drugs prescribed in the management of URTIs.Methods: This was a cross-sectional study. Data was collected from records of 300 outpatients clinically diagnosed as URTIs from SSIMS and RC Hospital, Davangere between January 2015 and June 2016. The prescribing patterns, approval status and listing of drugs in World Health Organization (WHO) essential medicines list/ National List of Essential Medicines (NLEM) were analysed. The data was presented as percentages, mean and standard deviations.Results: A total of 300 cases were studied. Among these, acute pharyngitis (29%) and acute sinusitis (26%) are the most common infections. Of the 300 cases studied, 283 (94.3%) were prescribed antimicrobials. Of the total 740 medications prescribed, 393 (53.1%) were fixed-dose combinations (FDCs). A total of 724 medications (97.8%) were approved by Drugs Controller General of India and 248 (33.5%) by Food and Drug Administration. Only 5.8% of the prescribed drugs have been listed in WHO’s and NLEM. The most common class of antibacterials prescribed was Beta-lactams.Conclusions: Oral formulations were preferred over parenteral formulations and FDCs were preferred over single drug formulations. Beta-lactams comprised the major class of antibacterial prescribed

An Enhanced Edge Detection Method Based on Integration of Entropy—Canny Technique

When analysing objects in images, it is necessary to distinguish the objects of interest from the background. This task can be achieved through segmentation process. Image segmentation is one of the most challenging issues in image processing domain. It remains an active research area with aims to distinguish between the foreground and background of objects. In order to extract the useful information from an image, edge detection is a reliable technique to solve this issue. Edge detection is a technique that aims at extracting the boundaries of the image by manipulating discontinuities gaps between pixels. This paper focuses on demonstrating an enhanced integrating framework; a modified entropy based approach with an enhanced Canny technique. By integrating two well-known techniques, the true edges were able to identify effectively. The peak signal-to-noise ratio (PSNR) and structural similarity index measure (SSIM) for the proposed technique shown was 4.1% and 16.75% higher than prominent techniques respectively. The proposed technique produced better similarity quality image and contains lesser noise

UV/Optical Detections of Candidate Tidal Disruption Events by GALEX and CFHTLS

We present two luminous UV/optical flares from the nuclei of apparently inactive early-type galaxies at z=0.37 and 0.33 that have the radiative properties of a flare from the tidal disruption of a star. In this paper we report the second candidate tidal disruption event discovery in the UV by the GALEX Deep Imaging Survey, and present simultaneous optical light curves from the CFHTLS Deep Imaging Survey for both UV flares. The first few months of the UV/optical light curves are well fitted with the canonical t^(-5/3) power-law decay predicted for emission from the fallback of debris from a tidally disrupted star. Chandra ACIS X-ray observations during the flares detect soft X-ray sources with T_bb= (2-5) x 10^5 K or Gamma > 3 and place limits on hard X-ray emission from an underlying AGN down to L_X (2-10 keV) <~ 10^41 ergs/s. Blackbody fits to the UV/optical spectral energy distributions of the flares indicate peak flare luminosities of > 10^44-10^45 ergs/s. The temperature, luminosity, and light curves of both flares are in excellent agreement with emission from a tidally disrupted main sequence star onto a central black hole of several times 10^7 msun. The observed detection rate of our search over ~ 2.9 deg^2 of GALEX Deep Imaging Survey data spanning from 2003 to 2007 is consistent with tidal disruption rates calculated from dynamical models, and we use these models to make predictions for the detection rates of the next generation of optical synoptic surveys.Comment: 28 pages, 27 figures, 11 tables, accepted to ApJ, final corrections from proofs adde

The HST Survey of BL Lac Objects: Gravitational Lens Candidates and Other Unusual Sources

We present HST observations of seven unusual objects from the HST ``snapshot survey'' of BL Lac objects, of which four are gravitational lens candidates. In three cases a double point sources is observed: 0033+595, with 1.58 arcsec separation, and 0502+675 and 1440+122, each with $\sim 0.3$ arcsec separation. The last two also show one or more galaxies, which could be either host or lensing galaxies. If any are confirmed as lenses, these BL Lac objects are excellent candidates for measuring H$_0$ via gravitational time delay because of their characteristic rapid, high amplitude variability. An additional advantage is that, like other blazars, they are likely superluminal radio sources, in which case the source plane is mapped out over a period of years, providing strong additional constraints on the lensing mass distribution. The fourth gravitational lens candidate is 1517+656, which is surrounded by three arclets forming an almost perfect ring of radius 2.4 arcsec. If this is indeed an Einstein ring, it is most likely a background source gravitationally lensed by the BL Lac object host galaxy and possibly a surrounding group or cluster. In the extreme case that all four candidates are true lenses, the derived frequency of gravitational lensing in this BL Lac sample would be an order of magnitude higher than in comparable quasar samples. We also report on three other remarkable BL Lac objects: 0138-097, which is surrounded by a large number of close companion galaxies; 0806+524, whose host galaxy contains an uncommon arc-like structure; and 1959+650, which is hosted by a gas rich elliptical galaxy with a prominent dust lane of $\sim 5\times 10^5 M_\odot$.Comment: 29 pages in total, 12 figure