Carried Out (carried + out)

Distribution by Scientific Domains


Selected Abstracts


Dynamic emission properties of pulsars B0943+10 and B1822,09 , I. Comparison, and the discovery of a ,Q'-mode precursor

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2010
Isaac Backus
ABSTRACT This paper reports new observations of pulsars B0943+10 and B1822,09 carried out with the Arecibo Observatory and the Giant Metrewave Radio Telescope, respectively. Both stars exhibit two stable emission modes. We report the discovery in B0943+10 of a highly linearly polarized ,precursor' (PC) component that occurs primarily in only one mode. This emission feature closely resembles B1822,09's PC which also occurs brightly in only one mode. B0943+10's other mode is well known for its highly regular drifting subpulses that are apparently produced by a rotating ,carousel' system of 20 ,beamlets.' Similarly, B1822,09 exhibits subpulse-modulation behaviour only in the mode where its PC is absent. We survey our 18 h of B0943+10 observations and find that the ,sideband'-modulation features, from which the carousel-rotation time can be directly determined, occur rarely , less than 5 per cent of the time , but always indicating 20 ,beamlets'. We present an analysis of B1822,09's modal modulation characteristics at 325 MHz and compare them in detail with B0943+10. The pulsar never seems to null, and we find a 43-rotation-period P3 feature in the star's ,Q' mode that modulates the interpulse (IP) as well as the conal features in the main pulse (MP). We conclude that B1822,09 must have a nearly orthogonal geometry and that its carousel circulation time is long compared to the modal subsequences available in our observations, and the MP/IP separation is almost exactly 180. We conclude the PCs for both stars are incompatible with core,cone emission. We assess the interesting suggestion by Dyks et al. that downward-going radiation produces B1822,09's PC emission. [source]


Photometric study of the OB star clusters NGC 1502 and NGC 2169 and mass estimation of their members at the University Observatory Jena,

ASTRONOMISCHE NACHRICHTEN, Issue 5 2009
M.M. Hohle
Abstract In this work we present detailed photometric results of the trapezium like galactic nearby OB clusters NGC 1502 and NGC 2169 carried out at the University Observatory Jena. We determined absolute BVRI magnitudes of the mostly resolved components using Landolt standard stars. This multi colour photometry enables us to estimate spectral type and absorption as well as the masses of the components, which were not available for most of the cluster members in the literature so far, using models of stellar evolution. Furthermore, we investigated the optical spectrum of the components ADS 2984A and SZ Cam of the sextuple system in NGC 1502. Our spectra clearly confirm the multiplicity of these components, which is the first investigation of this kind at the University Observatory Jena ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Educational and Research Implications of Portable Human Patient Simulation in Acute Care Medicine

ACADEMIC EMERGENCY MEDICINE, Issue 11 2008
Leo Kobayashi MD
Abstract Advanced medical simulation has become widespread. One development, the adaptation of simulation techniques and manikin technologies for portable operation, is starting to impact the training of personnel in acute care fields such as emergency medicine (EM) and trauma surgery. Unencumbered by cables and wires, portable simulation programs mitigate several limitations of traditional (nonportable) simulation and introduce new approaches to acute care education and research. Portable simulation is already conducted across multiple specialties and disciplines. In situ medical simulations are those carried out within actual clinical environments, while off-site portable simulations take place outside of clinical practice settings. Mobile simulation systems feature functionality while moving between locations; progressive simulations are longer-duration events using mobile simulations that follow a simulated patient through sequential care environments. All of these variants have direct applications for acute care medicine. Unique training and investigative opportunities are created by portable simulation through four characteristics: 1) enhancement of experiential learning by reframing training inside clinical care environments, 2) improving simulation accessibility through delivery of training to learner locations, 3) capitalizing on existing care environments to maximize simulation realism, and 4) provision of improved training capabilities for providers in specialized fields. Research agendas in acute care medicine are expanded via portable simulation's introduction of novel topics, new perspectives, and innovative methodologies. Presenting opportunities and challenges, portable simulation represents an evolutionary progression in medical simulation. The use of portable manikins and associated techniques may increasingly complement established instructional measures and research programs at acute care institutions and simulation centers. [source]


The use of renal scintigraphy in assessing the potential for recovery in the obstructed renal tract in children

BJU INTERNATIONAL, Issue 9 2001
A. Thompson
Objective To assess the value of renal scintigraphy with 99mTc-dimercaptosuccinic acid (DMSA) in predicting functional recovery after the surgical relief of obstructed kidneys in children. Patients and methods Forty-three children underwent surgery to relieve upper urinary tract obstruction; 37 had pelvi-ureteric junction obstruction and six had vesico-ureteric junction obstruction. The indication for surgery was a combination of an obstructed renogram with symptoms of either pain or pyelonephritis. Most children (41) had < 40% function on the affected side before surgery, with just two having hyperfunction (> 55%). In all patients intravenous urography before surgery showed hydronephrosis, and a micturating cystogram was used to exclude coexisting reflux in the presence of an associated megaureter. Diuretic renography (using 99mTc-mercaptoacetyl triglycine or 123I-hippuran) and DMSA scintigraphy were both carried out before surgery and the renography repeated 6 months afterward. Results The renographic drainage curves improved from obstructed to unobstructed or ,dilated unobstructed' on all postoperative studies. Regression analysis showed that preoperative DMSA scan was an excellent predictor of outcome (P < 0.001) whilst the preoperative renogram was a relatively poor predictor of the functional result. In four patients where the initial renographic function was < 10%, DMSA scintigraphy predicted correctly the capacity for recovery in three and the inability to improve in the fourth. Conclusion Before surgery, DMSA scintigraphy in children with upper urinary tract obstruction is a more useful estimate of probable long-term renal function than value from diuresis renography. If there is doubt about the desirability of reconstructive surgery, a DMSA scan may eliminate the need for more invasive methods of estimating recovery, e.g. a period of nephrostomy drainage. [source]