8 research outputs found

    A large topographic feature on the surface of the trans-Neptunian object (307261) 2002 MS4_4 measured from stellar occultations

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    This work aims at constraining the size, shape, and geometric albedo of the dwarf planet candidate 2002 MS4 through the analysis of nine stellar occultation events. Using multichord detection, we also studied the object's topography by analyzing the obtained limb and the residuals between observed chords and the best-fitted ellipse. We predicted and organized the observational campaigns of nine stellar occultations by 2002 MS4 between 2019 and 2022, resulting in two single-chord events, four double-chord detections, and three events with three to up to sixty-one positive chords. Using 13 selected chords from the 8 August 2020 event, we determined the global elliptical limb of 2002 MS4. The best-fitted ellipse, combined with the object's rotational information from the literature, constrains the object's size, shape, and albedo. Additionally, we developed a new method to characterize topography features on the object's limb. The global limb has a semi-major axis of 412 ±\pm 10 km, a semi-minor axis of 385 ±\pm 17 km, and the position angle of the minor axis is 121 ^\circ ±\pm 16^\circ. From this instantaneous limb, we obtained 2002 MS4's geometric albedo and the projected area-equivalent diameter. Significant deviations from the fitted ellipse in the northernmost limb are detected from multiple sites highlighting three distinct topographic features: one 11 km depth depression followed by a 255+4^{+4}_{-5} km height elevation next to a crater-like depression with an extension of 322 ±\pm 39 km and 45.1 ±\pm 1.5 km deep. Our results present an object that is \approx138 km smaller in diameter than derived from thermal data, possibly indicating the presence of a so-far unknown satellite. However, within the error bars, the geometric albedo in the V-band agrees with the results published in the literature, even with the radiometric-derived albedo

    Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

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    Contains fulltext : 172380.pdf (publisher's version ) (Open Access

    Sonographic real-time imaging of tissue perfusion in a porcine haemorrhagic shock model

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    Injection of fluorescence-labelled microspheres (FMs) in pigs allows only the postmortem determination of organ perfusion. Colour duplex ultrasound (CDU) and contrast-enhanced ultrasound were established as techniques for real-time imaging of tissue perfusion in a porcine haemorrhagic shock model. Haemorrhagic shock was provoked in nine domestic pigs by taking at least 15% of the calculated blood volume. Ultrasound examinations were performed with a Hitachi HI VISION Ascendus. SonoVue was injected for contrast-enhanced ultrasound. Monitoring of the resistive index and time-to-peak ratio enabled quantification of tissue perfusion in vivo during the entire study, allowing real-time differentiation of animals with systemic shock versus failing shock effect. Postmortem analyses of injected FMs confirmed the sonographic in vivo results. Determination of the resistive index and time-to-peak ratio by CDU and contrast-enhanced ultrasound allowed real-time monitoring of tissue perfusion. Effects of haemorrhagic shock and therapeutic approaches related to organ perfusion can be observed live and in vivo. (C) 2019 The Author(s). Published by Elsevier Inc. on behalf of World Federation for Ultrasound in Medicine & Biology

    Is applanation tonometry a reliable method for monitoring blood pressure in morbidly obese patients undergoing bariatric surgery?

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    Background: The aim of this study was to evaluate the validity of non-invasive continuous BP measurement by applanation tonometry in morbidly obese patients undergoing bariatric surgery. Methods: Arterial blood pressure (AP) was recorded intraoperatively both by applanation tonometry (AT) (T-Line 200pro, Tensys Medical(R), USA) and an arterial line (AL) after radial cannulation in obese patients undergoing bariatric surgery. Discrepancies between the two methods were assessed as bias, limits of agreement and percentage error. Mean, systolic, and diastolic arterial pressures were assessed (MAP, SAP, DAP respectively). Trending ability was assessed by concordance based on four-quadrant plotting. Results: Mean (SD) BMI of the 28 patients was 49.4 (9.7 kg m(-2)). A total of 201 907 time points were available for analysis. Bias for MAP(AT) compared with MAP(AL) was +3.97 mm Hg (SAP(AT) + 3.45 mm Hg; DAP(AT) +3.66 mm Hg) with limits of agreement for MAP(AT) of -14.47 and +22.41 mm Hg (SAP(AT) -22.0 and +28.9 mm Hg; DAP(AT) -15.7 and +23.1 mm Hg). Percentage error for MAP(AT) was 23.5% (23.4% for SAP(AT); 30.5% for DAP(AT)). Trending ability for MAP, SAP, and DAP revealed a concordance of 0.74, 0.72, and 0.71, respectively. Conclusions: Continuous BP assessment by applanation tonometry is feasible in morbidly obese patients undergoing bariatric surgery. However, despite a low mean difference, 95% limits of agreement and trending ability indicate that the technology needs to be improved further, before being recommended for routine use in this group of patients

    Assessing volume responsiveness using right ventricular dynamic indicators of preload

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    Purpose!#!Dynamic indicators of preload currently only do reflect preload requirements of the left ventricle. To date, no dynamic indicators of right ventricular preload have been established. The aim of this study was to calculate dynamic indicators of right ventricular preload and assess their ability to predict ventricular volume responsiveness.!##!Materials and methods!#!The study was designed as experimental trial in 20 anaesthetized pigs. Micro-tip catheters and ultrasonic flow probes were used as experimental reference to enable measurement of right ventricular stroke volume and pulse pressure. Hypovolemia was induced (withdrawal of blood 20 ml/kg) and thereafter three volume-loading steps were performed. ROC analysis was performed to assess the ability of dynamic right ventricular parameters to predict volume response.!##!Results!#!ROC analysis revealed an area under the curve (AUC) of 0.82 (CI 95% 0.73-0.89; p < 0.001) for right ventricular stroke volume variation (SVV!##!Conclusions!#!In our experimental animal setting, calculating dynamic indicators of right ventricular preload is possible and appears promising in predicting volume responsiveness

    Fatores de erros na mensuração da mortalidade infantil Error factors in the measurement of infant mortality

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    Dentre os indicadores de saúde tradicionalmente utilizados a mortalidade infantil destaca-se como um dos mais importantes. Frequentemente é utilizada por profissionais de saúde pública na caracterização do nível de saúde e em avaliações de programas. Existem, porém, vários fatores de erros que afetam o seu valor e dentre esses são destacados: a definição dos nascidos vivos e sua aplicação na prática, o sub-registro de óbito e de nascimento, o registro do óbito por local de ocorrência, a definição de nascido vivo no ano e a declaração errada na idade. Existem também erros qualitativos que dizem respeito, principalmente, a declarações erradas da causa de morte. Vários desses fatores foram medidos para São Paulo.<br>Among the traditionally used health indices the infant mortality rate is distinguished as the most important one. Frequently it is used by the public health professionals for health level characterization and for the evaluation of programmes. There are, however, several error factors that affect its value, among which are the live birth definition and its true use; underregistration of deaths and births; the death register by place of occurrence; live birth definition in the year, and the wrong age information. There are also qualitative errors due to wrong information as regards the causes of death. Several of these factors were discussed for S. Paulo
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