5,467 research outputs found

    A Mid-Infrared Galaxy Atlas (MIGA)

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    A mid-infrared atlas of part of the Galactic plane (75∘<l<148∘,b=±6∘75^\circ < l < 148^\circ, b = \pm6^\circ) has been constructed using HIRES processed infrared data to provide a mid-infrared data set for the Canadian Galactic Plane Survey (CGPS). The addition of this data set to the CGPS will enable the study of the emission from the smallest components of interstellar dust at an angular resolution comparable to that of the radio, millimetre, and far-infrared data in the CGPS. The Mid-Infrared Galaxy Atlas (MIGA) is a mid-infrared (12 ÎŒ\mum and 25 ÎŒ\mum) counterpart to the far-infrared IRAS Galaxy Atlas (IGA), and consists of resolution enhanced (∌0.5â€Č\sim 0.5' resolution) HIRES images along with ancillary maps. This paper describes the processing and characteristics of the atlas, the cross-beam simulation technique used to obtain high-resolution ratio maps, and future plans to extend both the IGA and MIGA.Comment: 38 pages (including 15 tables), 13 figures (8 dithered GIF and 5 EPS). Submitted to Astrophysical Journal Supplement Series. A preprint with higher resolution figures is available at http://www.cita.utoronto.ca/~kerton/publications.htm

    Prevalence and risk factors for mast cell tumours in dogs in England

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    BACKGROUND: Mast cell tumour (MCT) appears to be a frequent tumour type in dogs, though there is little published in relation to its frequency in dogs in the UK. The current study aimed to investigate prevalence and risk factors for MCTs in dogs attending English primary-care veterinary practices. METHODS: Electronic patient records from practices participating in the VetCompass animal surveillance project between July 2007 and June 2013 were searched for MCT diagnosis. Various search terms and standard diagnostic terms (VeNom codes) identified records containing MCT diagnoses, which were evaluated against clinical criteria for inclusion to the study. MCT prevalence for the entire dataset and specific breed types were calculated. Descriptive statistics characterised MCT cases and multivariable logistic regression methods evaluated risk factors for association with MCT (P < 0.05). RESULTS: Within a population of 168,636 dogs, 453 had MCT, yielding a prevalence of 0.27% (95% confidence interval (CI) 0.24% - 0.29%). The highest breed type specific prevalences were for the Boxer at 1.95% (95% CI 1.40% - 2.51%), Golden Retriever at 1.39% (0.98% - 1.81%) and Weimaraner at 0.85% (95% CI 0.17% to 1.53%). Age, insurance status, neuter status, weight and breed type were associated with MCT diagnosis. Of dogs of specific breed type, the Boxer, Pug and Staffordshire Bull Terrier showed greater odds of MCT diagnosis compared with crossbred dogs. Conversely, the German Shepherd Dog, Border Collie, West Highland White Terrier, Springer Spaniel and Cocker Spaniel had reduced odds of MCT diagnosis compared with crossbred dogs. No association was found between MCT diagnosis and sex. CLINICAL SIGNIFICANCE: This study highlights a clinically significant prevalence of MCT and identifies specific breed types with predisposition to MCT, potentially aiding veterinarian awareness and facilitating diagnosis

    Polarization dependent photoionization cross-sections and radiative lifetimes of atomic states in Ba

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    The photoionization cross-sections of two even-parity excited states, 5d6d3D15d6d ^3D_1 and 6s7d3D26s7d ^3D_{2}, of atomic Ba at the ionization-laser wavelength of 556.6 nm were measured. We found that the total cross-section depends on the relative polarization of the atoms and the ionization-laser light. With density-matrix algebra, we show that, in general, there are at most three parameters in the photoionization cross-section. Some of these parameters are determined in this work. We also present the measurement of the radiative lifetime of five even-parity excited states of barium.Comment: 11 pages, 7 figure

    Variation in Heat Transfer During Transient Heating of a Hemisphere at a Mach Number of 2

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    Convective heat-transfer tests were made on a 5-inch-diameter hemisphere to determine the variation of Stanton number with the ratio of wall temperature to total temperature. The tests were made at a nominal Mach number of 2 for stagnation temperatures of 760 deg R, 1,030 deg R, and 1,380 deg R. The model was constructed so that radiation effects and also streamwise conduction effects within the model skin were minimized. The results of the tests verified that these effects were small. Tests which were made with different masses of air inside the model to check for conduction effects to the internal air cavity showed these effects to be negligible. For laminar flow on the hemisphere, the Stanton number remained essentially constant as the ratio of wall temperature to total temperature increased. However, for fully established turbulent flow, the Stanton number at some stations decreased on the order of 50 percent as the ratio of wall temperature to total temperature increased. A theory which agreed fairly well with the trend of this decrease is shown for comparison

    Ultrastable lasers based on vibration insensitive cavities

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    We present two ultra-stable lasers based on two vibration insensitive cavity designs, one with vertical optical axis geometry, the other horizontal. Ultra-stable cavities are constructed with fused silica mirror substrates, shown to decrease the thermal noise limit, in order to improve the frequency stability over previous designs. Vibration sensitivity components measured are equal to or better than 1.5e-11 per m.s^-2 for each spatial direction, which shows significant improvement over previous studies. We have tested the very low dependence on the position of the cavity support points, in order to establish that our designs eliminate the need for fine tuning to achieve extremely low vibration sensitivity. Relative frequency measurements show that at least one of the stabilized lasers has a stability better than 5.6e-16 at 1 second, which is the best result obtained for this length of cavity.Comment: 8 pages 12 figure

    Informal task-sharing practices in inpatient newborn settings in a low-income setting-A task analysis approach.

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    Aim To describe the complexity and criticality of neonatal nursing tasks and existing task‐sharing practices to identify tasks that might be safely shared in inpatient neonatal settings. Design We conducted a cross‐sectional study in a large geographically dispersed sample using the STROBE guidelines. Methods We used a task analysis approach to describe the complexity/criticality of neonatal nursing tasks and to explore the nature of task sharing using data from structured, self‐administered questionnaires. Data was collected between 26th April and 22nd August 2017. Results Thirty‐two facilities were surveyed between 26th April and 22nd August, 2017. Nearly half (42%, 6/14) of the “moderately critical” and “not critical” (41%, 5/11) tasks were ranked as consuming most of the nurses' time and reported as shared with mothers respectively. Most tasks were reported as shared in the public sector than in the private‐not‐for‐profit facilities. This may largely be a response to inadequate nurse staffing, as such, there may be space for considering the future role of health care assistants

    Excited-State Photophysics of Hypericin and Its Hexamethoxy Analog:  Intramolecular Proton Transfer as a Nonradiative Process in Hypericin

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    The excited-state photophysics of the light induced antiviral agent, hypericin, are compared with those of its methylated analog, hexamethoxyhypericin. This comparison is instructive in understanding both the ground- and the excited-state properties of hypericin. That the hexamethoxy analog has no labile protons that can be transferred, that it cannot protonate its own carbonyl groups, that it has a reduced fluorescence quantum yield and lifetime with respect to hypericin, and that it exhibits no stimulated emission or, more specifically, rise time in stimulated emission completely support our emerging model of the hypericin photophysics. The results are consistent with the presence of intramolecular excited-state proton transfer in hypericin but not in its methylated analog

    Unusually large polarizabilities and "new" atomic states in Ba

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    Electric polarizabilities of four low-J even-parity states and three low-J odd-parity states of atomic barium in the range 35,60035,600 to $36,000\ cmcm^{-1}areinvestigated.Thestatesofinterestareexcited(inanatomicbeam)viaanintermediateodd−paritystatewithasequenceoftwolaserpulses.Theodd−paritystatescanbeexcitedduetotheStark−inducedmixingwitheven−paritystates.Thepolarizabilitiesaremeasuredviadirectspectroscopyonthesecond−stagetransition.Severalstateshavetensorandscalarpolarizabilitiesthatexceedthevaluesthatmightbeexpectedfromtheknownenergylevelsofbariumbymorethantwoordersofmagnitude.TwooftheStark−inducedtransitionscannotbeidentifiedfromtheknownenergyspectrumofbarium.Theobservationssuggesttheexistenceofasyetunidentifiedodd−parityenergystates,whoseenergiesandangularmomentaaredeterminedinthepresentexperiment.Atentativeidentificationofthesestatesas[Xe] are investigated. The states of interest are excited (in an atomic beam) via an intermediate odd-parity state with a sequence of two laser pulses. The odd-parity states can be excited due to the Stark-induced mixing with even-parity states. The polarizabilities are measured via direct spectroscopy on the second-stage transition. Several states have tensor and scalar polarizabilities that exceed the values that might be expected from the known energy levels of barium by more than two orders of magnitude. Two of the Stark-induced transitions cannot be identified from the known energy spectrum of barium. The observations suggest the existence of as yet unidentified odd-parity energy states, whose energies and angular momenta are determined in the present experiment. A tentative identification of these states as [Xe]6s8p ^3P_{0,2}$ is suggested.Comment: 29 pages, 12 figure
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