José Neves

Acute kidney injury in patients with sepsis: a contemporary analysis

OBJECTIVES To analyze the clinical characteristics of septic acute kidney injury (AKI) according to the Acute Kidney Injury Network (AKIN) classification, and to evaluate the capacity of this system in predicting in-hospital mortality of septic patients. METHODS Patients with sepsis admitted to the infectious diseases intensive care unit (ICU) of our hospital between January 2004 and June 2007 were retrospectively studied. Maximum AKIN stage within the first three days of hospitalization was recorded. RESULTS Three hundred fifteen patients were evaluated. According to AKIN criteria, 99 patients (31.4%) had AKI: 26.2% at stage 1, 20.2% at stage 2, and 53.6% at stage 3. Four patients (1.9%) with no AKI progressed to stage 1, two patients (7.7%) at stage 1 progressed to stage 2, one patient (3.8%) at stage 1 progressed to stage 3, and one patient at stage 2 (5%) progressed to stage 3. The mortality rate was 25.3% and increased significantly from normal renal function to stage 3 (normal, 12.5%; stage 1, 34.6%; stage 2, 45%; stage 3, 64.1%; p<0.0001). After adjusting for age, gender, race, pre-existing chronic kidney disease, illness severity as evaluated by acute physiology and chronic health evaluation, version II (APACHE II) score, need for mechanical ventilation, and vasopressor use, AKIN stage 1 (odds ratio (OR) 3.03, 95% confidence interval (CI) 1.12-8.19, p=0.029), stage 2 (OR 3.3, 95% CI 1.11-9.78, p=0.031), and stage 3 (OR 7.35, 95% CI 3.13-17.25, p<0.0001) predicted mortality. CONCLUSIONS AKIN criteria are a useful tool to characterize and stratify septic patients according to the risk of death.

Using Conical and Spherical Mirrors with Conventional Cameras for 360° Panorama Views in a Single Image

Conventional video cameras with projective lens have restricted fields of view. Adding mirrors of different shapes, 360deg panoramic views can be achieved in a single image. For robotic football, we envisage a simple and low cost setup. The system presented uses a single home made conical mirror. The setup conditions can be easily adjusted to cover other mirror shapes, such as spherical, paraboloidal, hyperboloidal and other shapes generated by axial revolution. The single viewpoint restrictions, usually imposed for general uses, are overcome by the specific setup conditions

Phase Space Signal Filtering

In this article we propose an approach based on the analysis of phase space of time series, in order to improve the filtering process. In some applications the traditional filtering process can produce results that lead to a insufficient representation of the information contained in the signal. Using phase space we can have a different meaning for noise, its correlation with the signal and a supporting theory for accurate filtering.

Simple camera calibration for light measurements

The availability and decreasing prices of digital photographic cameras using megapixel sensors could point to its use as high quality light measuring devices if simple and effective calibration procedures could be put to work. This paper proposes such a system, using a common digital camera combined with low cost reference color charts. The procedure to obtain the response function of the camera, the production of the color chart and its calibration is presented. In this way, it is possible to obtain light measurements otherwise only possible with sophisticated and expensive equipments.