786 research outputs found

    Modelling the Spoon IRS diagnostic diagram

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    We explore whether our models for starbursts, quiescent star-forming galaxies and for AGN dust tori are able to model the full range of IRS spectra measured with Spitzer. The diagnostic plot of 9.7 mu silicate optical depth versus 6.2 mu PAH equivalent width, introduced by Spoon and coworkers in 2007, gives a good indication of the age and optical depth of a starburst, and of the contribution of an AGN dust torus. However there is aliasing between age and optical depth at later times in the evolution of a starburst, and between age and the presence of an AGN dust torus. Modeling the full IRS spectra and using broad-band 25-850 mu fluxes can help to resolve these aliases. The observed spectral energy distributions require starbursts of a range of ages with initial dust optical depth ranging from 50-200, optically thin dust emission ('cirrus') illuminated by a range of surface brightnesses of the interstellar radiation field, and AGN dust tori with a range of viewing angles.Comment: Accepted for publication by MNRAS. 8 pages, 10 figure

    ISO observations and models of galaxies with Hidden Broad Line Regions

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    We present ISO mid-infrared spectrophotometry and far-infrared photometry of galaxies with Hidden Broad Line Regions (HBLR). We also present radiative transfer models of their spectral energy distributions which enable us to separate the contributions from the dusty disc of the AGN and the dusty starbursts. We find that the combination of tapered discs (discs whose thickness increases with distance from the central source in the inner part but stays constant in the outer part) and starbursts provide good fits to the data. The tapered discs dominate in the mid-infrared part of the spectrum and the starbursts in the far-infrared. After correcting the AGN luminosity for anisotropic emission we find that the ratio of the AGN luminosity to the starburst luminosity, L(AGN)/L(SB), ranges from about unity for IRAS14454-4343 to about 13 for IRAS01475-0740. Our results suggest that the warm IRAS colours of HBLR are due to the relatively high L(AGN)/L(SB). Our fits are consistent with the unified model and the idea that the infrared emission of AGN is dominated by a dusty disc in the mid-infrared and starbursts in the far-infrared.Comment: A&A accepeted, 8pages 2 Figures, final versio

    Interview of Margaret Mary Markmann, Ph.D.

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    Dr. Markmann was born in 1948 at the Anderson Hospital in Center City, Philadelphia. She was the fourth of eleven children born into a household of her mother, her father and her grandparents. She grew up in Philadelphia and has lived in the area for her entire life only leaving once after she completed nursing school. During her childhood her extended family lived nearby, her grandmother lived down the street and her Aunt and Uncle lived in the opposite direction. Her father was the direct descendent of Irish immigrants who settled in South West Philadelphia and lived in Southwest Philadelphia for the entirety of their lives. The family also had a summer home in Avalon, New Jersey. Dr. Markmann attended school in one of the largest Catholic Parishes in the United States. There were normally ninety students in the classroom. The school was very large and had 3,300 students attending when she was going to the school. Education was very important for Dr. Markmann and her siblings growing up. Both her father and mother made a point to try and send all eleven of them to college or some form of higher education. After she finished high school she took what she believed was the more practical option as compared to her original desire to become a doctor. Dr. Markmann went to nursing school at St. Joseph’s Hospital School of Nursing in Philadelphia Pennsylvania. She graduated in August 1969 and became a registered nurse. Dr. Markmann worked in the field nursing for a large portion if her professional life. Her first experience was as an emergency room nurse, a position that she held for one year before becoming a Clinical instructor at St. Joseph’s Hospital School of Nursing. She went back to school to get her Bachelor of Arts degree which she received in 1998 from La Salle University with a major in History and a minor in English. She received her Master of Arts from Temple University in 2001. Her original intention was to use that degree to teach high school students. However after she had contacted the Arch Diocese she did not hear back from them for four years. During that time she was contacted to teach a few history courses at La Salle University. That was the start of her professional life at La Salle University. She has been teaching at La Salle University as an adjunct professor since 2002. The majority of the courses that Dr. Markmann teaches at La Salle are Global history courses, most notably HIS 151 and HIS 251. She has also worked in the Dean of Arts and Sciences office as a student advisor for five years, non-consecutively. Many of her children have attended La Salle University and her husband is currently on the Board of Trustees at La Salle. She has been a member of the Parents association at La Salle and both she and her husband have set up the Markmann scholarship for students who attended Catholic School

    An Empirical Evaluation of the ClubsNSW (Australia) Multi-Venue Self-Exclusion Program

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    Few empirical studies have evaluated the effectiveness of self-exclusion programs. Research is required to identify factors contributing to decisions to enter and/or breach self-exclusion orders, or to self-excluded gamblers to seek additional treatment. Clinical characteristics of self-excluders remain relatively unknown in addition to factors that differentiate gamblers who do or do not breach. Limitations of current programs are that gamblers can self-exclude from only one or a limited number of venues. The Multi-venue Self-exclusion program, developed and implemented by ClubsNSW (Australia), is a centralised web-based system designed to help problem gamblers self exclude from up to 35 venues at a time. The online system presents gamblers with the choice of registering from within the venue assisted by the club manager or a trained staff member, or to self-exclude offsite through a gambling counsellor. In a retrospective design, the population characteristics, and the motivations and behaviours of a sample of self-excluded gamblers will be described; the implications of the study findings for the management of the Multi-venue Self-exclusion program will be discussed

    Anomalous optical surface absorption in nominally pure silicon samples at 1550 nm

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    The announcement of the direct detection of Gravitational Waves (GW) by the LIGO and Virgo collaboration in February 2016 has removed any uncertainty around the possibility of GW astronomy. It has demonstrated that future detectors with sensitivities ten times greater than the Advanced LIGO detectors would see thousands of events per year. Many proposals for such future interferometric GW detectors assume the use of silicon test masses. Silicon has low mechanical loss at low temperatures, which leads to low displacement noise for a suspended interferometer mirror. In addition to the low mechanical loss, it is a requirement that the test masses have a low optical loss. Measurements at 1550 nm have indicated that material with a low enough bulk absorption is available; however there have been suggestions that this low absorption material has a surface absorption of > 100 ppm which could preclude its use in future cryogenic detectors. We show in this paper that this surface loss is not intrinsic but is likely to be a result of particular polishing techniques and can be removed or avoided by the correct polishing procedure. This is an important step towards high gravitational wave detection rates in silicon based instruments

    Hybridisation:A ‘double-edged sword’ for neotropical plant diversity

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    Hybridization can facilitate both evolutionary diversification and extinction and has had a critical role in plant evolution, with c. 25% of species known to hybridize in some temperate floras. However, in the species-rich Neotropical flora, the role of hybridization in the evolution of diversity remains unclear. Our review examines studies of hybridization in seed plants from across the Neotropics and explores its outcomes on Neotropical plant evolution. We review studies on a per-biome basis and a spectrum of evolutionary outcomes from hybridization are evident across Neotropical biomes and taxa. These range from short-term impacts, such as the broadening of ecological amplitude in hybrid progeny with transgressive phenotypes and genetic swamping, through to long term impacts, such as the generation of new lineages. Among these studies certain themes emerge, such as the pervasive hybridization among species-rich plant radiations from the Andean páramos, suggesting a role for hybridization in rapid diversification events. Finally, we highlight that hybridization is relatively understudied in the Neotropical flora, despite its remarkable species richness. The advent of genomic techniques can facilitate the study of hybridization and its effects in understudied biomes and plant groups. The increasing availability of genomic resources will eventually allow comparisons between tropical and temperate floras and therefore shed light on the evolutionary impacts of hybridization across the latitudinal biodiversity gradient

    A comparison of urology training across five major english-speaking countries

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    © 2020 The Author(s). This article is licensed under the Creative Commons Attribution- NonCommercial-NoDerivatives 4.0 International License (CC BY- NC-ND) (http://www.karger.com/Services/OpenAccessLicense). Usage and distribution for commercial purposes as well as any dis-tribution of modified material requires written permission.Background: Urology is a rapidly evolving specialty, although wide variations exist between training programs in different countries. We aimed to compare the status of urology training in 5 English-speaking countries. Materials and Methods: Features compared include the training pathway structure, training requirements, competition levels and the process of moving country for international medical graduates. Results: Length of training varied considerably across countries, ranging from 5 years in the USA and Canada, to 7 years in Australia and New Zealand and 9 years in the UK. Ease of entering urology training for international medical graduates also varies, with the UK relatively easier compared to other countries. All countries encourage participation in research during training as well as completion of non-urology and urology specific surgical examinations. Conclusion: Following the Royal College of Surgeons Improving Surgical Training report, it is vital that the UK incorporates optimal elements of international programs in order to provide the best standards for trainees and world-class care in urology.Peer reviewe

    Constraining the Cosmological Constant from Large-Scale Redshift-Space Clustering

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    We show how the cosmological constant can be estimated from redshift surveys at different redshifts, using maximum-likelihood techniques. The apparent redshift-space clustering on large scales (\simgt 20 \himpc) are affected in the radial direction by infall, and curvature influences the apparent correlations in the transverse direction. The relative strengths of the two effects will strongly vary with redshift. Using a simple idealized survey geometry, we compute the smoothed correlation matrix of the redshift-space correlation function, and the Fisher matrix for \omm and \oml. These represent the best possible measurement of these parameters given the geometry. We find that the likelihood contours are turning, according to the behavior of the angular-diameter distance relation. The clustering measures from redshift surveys at intermediate-to-high redshifts can provide a surprisingly tight constraint on \oml. We also estimate confidence contours for real survey geometries, using the SDSS LRG and QSO surveys as specific examples. We believe that this method will become a practical tool to constrain the nature of the dark energy.Comment: 10 pages, 3 figures, submitted to ApJ Letter

    A 610-MHz survey of the ELAIS-N1 field with the Giant Metrewave Radio Telescope - Observations, data analysis and source catalogue

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    Observations of the ELAIS-N1 field taken at 610 MHz with the Giant Metrewave Radio Telescope are presented. Nineteen pointings were observed, covering a total area of 9 square degrees with a resolution of 6" x 5", PA +45 deg. Four of the pointings were deep observations with an rms of 40 microJy before primary beam correction, with the remaining fifteen pointings having an rms of 70 microJy. The techniques used for data reduction and production of a mosaicked image of the region are described, and the final mosaic is presented, along with a catalogue of 2500 sources detected above 6 sigma. This work complements the large amount of optical and infrared data already available on the region. We calculate 610-MHz source counts down to 270 microJy, and find further evidence for the turnover in differential number counts below 1 mJy, previously seen at both 610 MHz and 1.4 GHz.Comment: 12 pages, 18 figures, two tables. Table 1 can be found in full via http://www.mrao.cam.ac.uk/surveys/ . Accepted for publication in MNRA
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