A return to strong radio flaring by Circinus X-1 observed with the Karoo Array Telescope test array KAT-7

Circinus X-1 is a bright and highly variable X-ray binary which displays strong and rapid evolution in all wavebands. Radio flaring, associated with the production of a relativistic jet, occurs periodically on a ~17-day timescale. A longer-term envelope modulates the peak radio fluxes in flares, ranging from peaks in excess of a Jansky in the 1970s to an historic low of milliJanskys during the years 1994 to 2007. Here we report first observations of this source with the MeerKAT test array, KAT-7, part of the pathfinder development for the African dish component of the Square Kilometre Array (SKA), demonstrating successful scientific operation for variable and transient sources with the test array. The KAT-7 observations at 1.9 GHz during the period 13 December 2011 to 16 January 2012 reveal in temporal detail the return to the Jansky-level events observed in the 1970s. We compare these data to contemporaneous single-dish measurements at 4.8 and 8.5 GHz with the HartRAO 26-m telescope and X-ray monitoring from MAXI. We discuss whether the overall modulation and recent dramatic brightening is likely to be due to an increase in the power of the jet due to changes in accretion rate or changing Doppler boosting associated with a varying angle to the line of sight.Comment: 7 pages, 5 figures, accepted for publication in MNRAS 14 May 201

Radio observations of NGC 6388: an upper limit on the mass of its central black hole

We present the results of deep radio observations with the Australia Telescope Compact Array (ATCA) of the globular cluster NGC 6388. We show that there is no radio source detected (with a r.m.s. noise level of 27 uJy) at the cluster centre of gravity or at the locations of the any of the Chandra X-ray sources in the cluster. Based on the fundamental plane of accreting black holes which is a relationship between X-ray luminosity, radio luminosity and black hole mass, we place an upper limit of 1500 M_sun on the mass of the putative intermediate-mass black hole located at the centre of NGC 6388. We discuss the uncertainties of this upper limit and the previously suggested black hole mass of 5700 M_sun based on surface density profile analysis.Comment: 6 pages, 2 figures, accepted for publication in MNRA

A lung computed tomography assessment of positive end-expiratory pressureinduced lung overdistention

OBJETIVO: O objetivo do presente estudo foi determinar o limite tomográfico da hiperdistensão pulmonar em indivíduos normais, bem como avaliar o recrutamento e a hiperdistensão pulmonares induzidos pela pressão expiratória final positiva em pacientes com lesão pulmonar aguda. MATERIAIS E MÉTODOS: Inicialmente, o limite da hiperdistensão pulmonar foi determinado em seis voluntários sadios, nos quais tomografias computadorizadas espiraladas de tórax foram obtidas em capacidade residual funcional e em capacidade pulmonar total mais pressão positiva de 30 cm H2O. Posteriormente, foram avaliados seis pacientes com lesão pulmonar aguda nos quais as tomografias foram obtidas em zero de pressão expiratória final positiva e em pressão expiratória final positiva. As tomografias computadorizadas foram realizadas do ápex ao diafragma, e os volumes pulmonares quantificados por análise dos histogramas de densidade RESULTADOS: A análise dos histogramas de densidade em voluntários sadios em capacidade residual funcional mostrou histogramas monofásicos, com um pico em -791 + 12 UH. Em capacidade pulmonar total, o volume pulmonar aumentou em 79 + 35% e o pico das densidades pulmonares caiu para -886 + 26 UH. Mais de 70% do aumento no volume pulmonar foi localizado abaixo de -900 UH, sugerindo que este valor possa ser definido como o limite da hiperdistensão. Os pacientes com lesão pulmonar aguda mostraram em zero de pressão expiratória final positiva uma distribuição monofásica (n=3) ou bifásica (n=3), com densidades pulmonares médias situadas em 319 + 34 UH. Com a aplicação de pressão expiratória final positiva, o volume pulmonar aumentou em 47 + 19%, enquanto que as densidades pulmonares caíram para -538 + 171 UH. Pressão expiratória final positiva induziu um recrutamento alveolar de 320 + 160 ml e uma hiperdistensão de 238 + 320 ml. CONCLUSÕES: O limite de hiperdistensão em voluntários sadios foi de -900 UH. Este limite pode ser usado em pacientes com lesão pulmonar aguda para diferenciar recrutamento alveolar de hiperdistensão pressão expiratória final positiva induzidos.OBJECTIVE: The aim of the present study was to establish the tomographic limit of lung overdistention in normal individuals as well as to assess positive end-expiratory pressure-induced overdistention and alveolar recruitment in patients with acute lung injury. MATERIALS AND METHODS: Lung distention was first determined in six healthy volunteers in whom computed tomographic sections were obtained at functional residual capacity and total lung capacity with a positive airway pressure of 30 cmH2O. Tomographic scans at zero end-expiratory pressure and positive end-expiratory pressure were performed in six patients with acute lung injury. Computed tomographies were performed from the apex to the diaphragm and lung volumes were quantified by the analysis of the density histograms RESULTS: Analysis of the density histograms in healthy volunteers was monophasic with a peak at -791 ± 12 Housenfield units. In total lung capacity, lung volume increased by 79 ± 35% and the peak of lung density decreased to -886 ±26 Housenfield units. More than 70% of the increase in lung volume was located below -900 Housenfield units, suggesting that this value can be considered as the threshold separating normal aeration from overdistention. In patients with acute lung injury, at zero end-expiratory pressure the distribution of density histograms was either monophasic (n=3) or biphasic (n=3), with mean density of -319 ± 34 Housenfield units. With positive end-expiratory pressure application, lung volume increased by 47 ± 19%, while lung density decreased to -538 ± Housenfield units. Positive endexpiratory pressure induced a mean alveolar recruitment of 238 ±320 ml. CONCLUSIONS: The limit of overdistention in healthy individuals was -900 Housenfield units. This threshold can be used in patients with acute lung injury for differentiating alveolar recruitment from lung overdistention

Quality Indicators for Colonoscopy Procedures: A Prospective Multicentre Method for Endoscopy Units

BACKGROUND AND AIMS: Healthcare professionals are required to conduct quality control of endoscopy procedures, and yet there is no standardised method for assessing quality. The topic of the present study was to validate the applicability of the procedure in daily practice, giving physicians the ability to define areas for continuous quality improvement. METHODS: In ten endoscopy units in France, 200 patients per centre undergoing colonoscopy were enrolled in the study. An evaluation was carried out based on a prospectively developed checklist of 10 quality-control indicators including five dependent upon and five independent of the colonoscopy procedure. RESULTS: Of the 2000 procedures, 30% were done at general hospitals, 20% at university hospitals, and 50% in private practices. The colonoscopies were carried out for a valid indication for 95.9% (range 92.5-100). Colon preparation was insufficient in 3.7% (range 1-10.5). Colonoscopies were successful in 95.3% (range 81-99). Adenoma detection rate was 0.31 (range 0.17-0.45) in successful colonoscopies. CONCLUSION: This tool for evaluating the quality of colonoscopy procedures in healthcare units is based on standard endoscopy and patient criteria. It is an easy and feasible procedure giving the ability to detect suboptimal practice and differences between endoscopy-units. It will enable individual units to assess the quality of their colonoscopy techniques