Universidad Tecnológica de Bolívar

About: Universidad Tecnológica de Bolívar is a education organization based out in Cartagena, Colombia. It is known for research contribution in the topics: AC power & Computer science. The organization has 507 authors who have published 724 publications receiving 3900 citations. The organization is also known as: UTB & Utb.

Texture Analysis of Ultrasound Images for Pneumonia Detection in Pediatric Patients

Abstract: Pneumonia is a condition that can be life-threatening and affects a high number of children around the world. Lung ultrasound can be used for the diagnosis of pneumonia, but requires high experience. This paper presents an approach for pneumonia detection based on texture analysis of ultrasound images. Several measures were taken in healthy tissues and pneumonia lesions, and the most significant features were identified by statistical analysis. The results of the analysis of variance and exploratory analysis suggest that detection of pneumonia is possible based on image texture features.

Exact Relativistic Models of Thin Disks around Static Black Holes in a Magnetic Field

Abstract: The exact superposition of a central static black hole with surrounding thin disk in presence of a magnetic field is investigated. We consider two models of disk, one of infinite extension based on a Kuzmin–Chazy–Curzon metric and other finite based on the first Morgan–Morgan disk. We also analyze a simple model of active galactic nuclei (AGN) consisting of black hole, a Kuzmin–Chazy–Curzon disk and two rods representing jets, in presence of magnetic field. To explain the stability of the disks, we consider the matter of the disk made of two pressureless streams of counter-rotating charged particles (counter-rotating model) moving along electrogeodesic. Using the Rayleigh criterion, we derivate for circular orbits the stability conditions of the particles of the streams. The influence of the magnetic field on the matter properties of the disk and on its stability are also analyzed.

Effect of Deficit Irrigation on Yield, Quality, and Costs of the Production of Native Spearmint

Abstract: Water-saving strategies aimed at improving water use efficiency need to be applied in agriculture today to ensure sustainable use of scarce water resources. This article presents results of a 2-year study done at Washington State University’s Irrigated Agriculture Research and Extension Center (IAREC) to determine the effect of various water stress levels applied at various times during the growth period to the yield quantity, quality, and production costs of drip-irrigated native spearmint (Mentha spicata L.). The field experiment included four irrigation levels (40, 54, 80, and 100% of ETc) and four stress timings: T1(the irrigation levels were applied throughout the growing season), T2, T3, and T4 where the irrigation levels were applied 21, 14, and 7 days before harvest, respectively. Hay yields decreased with increasing water stress; mean annual hay yield ranged from 47.2 Mg/ha under the driest treatment (40% irrigation level at timing T1) to 61.2 Mg/ha under 100% irrigation level. Mean ann...