Universidad del Norte, Colombia

About: Universidad del Norte, Colombia is a education organization based out in Barranquilla, Colombia. It is known for research contribution in the topics: Population & Context (language use). The organization has 3562 authors who have published 4355 publications receiving 37861 citations. The organization is also known as: University of the North, Colombia & Uninorte.

Non-Local SVD Denoising of MRI Based on Sparse Representations.

Abstract: Magnetic Resonance (MR) Imaging is a diagnostic technique that produces noisy images, which must be filtered before processing to prevent diagnostic errors. However, filtering the noise while keeping fine details is a difficult task. This paper presents a method, based on sparse representations and singular value decomposition (SVD), for non-locally denoising MR images. The proposed method prevents blurring, artifacts, and residual noise. Our method is composed of three stages. The first stage divides the image into sub-volumes, to obtain its sparse representation, by using the KSVD algorithm. Then, the global influence of the dictionary atoms is computed to upgrade the dictionary and obtain a better reconstruction of the sub-volumes. In the second stage, based on the sparse representation, the noise-free sub-volume is estimated using a non-local approach and SVD. The noise-free voxel is reconstructed by aggregating the overlapped voxels according to the rarity of the sub-volumes it belongs, which is computed from the global influence of the atoms. The third stage repeats the process using a different sub-volume size for producing a new filtered image, which is averaged with the previously filtered images. The results provided show that our method outperforms several state-of-the-art methods in both simulated and real data.

A new species of Procephalothrix (Nemertea, Anopla, Archinemertea) from Chile

Abstract: A new species of archinemertean, Procephalothrix hermaphroditicus, is fully described and illustrated from specimens collected intertidally at Cocholgue and Metri, Chile The species is both the first member of the genus to be reported from Chilean waters, and the first recorded hermaphroditic archinemertean The systematics of the genus and its contained species are discussed

Leptospira spp. y leptospirosis humana

Abstract: Resumen Introduccion. La leptospirosis, enfermedad bacteriana zoonotica y emergente mas importante en el mundo, es causada por las especies patogenas de Leptospira spp. Objetivo. Revisar informacion reciente sobre Leptospira spp. y leptospirosis humana con enfasis en America y Colombia. Metodologia. Revision de articulos indexados en PubMed, relacionados con la microbiologia, epidemiologia, presentacion clinica en humanos, diagnostico, tratamiento y prevencion de la enfermedad (vacunas). Resultados. Veinte especies de Leptospira spp han sido descritas; se ha determinado la secuencia del ADN genomico de algunas cepas patogenas, la funcion de la mayoria de los genes involucrados en su patogenesis permanece desconocida. La leptospirosis humana presenta un rango de sintomas que van desde una fiebre indiferenciada hasta una ictericia, hemorragia, fallas renales y pulmonares severas. La administracion temprana e intravenosa de penicilina G es requerida para reducir las tasas de mortalidad, pero los antibioticos pueden no ser efectivos en la enfermedad pulmonar severa. En las Americas, las areas de alto riesgo son Brasil, Centro America y el Caribe. Pocos estudios han sido realizados en Colombia. La prueba serologica de oro, la microaglutinacion tiene alta sensibilidad y especificidad cuando se usan baterias de serovariedades locales pero es serogrupo especifica. Las vacunas generan respuestas especificas para la serovariedad usada, pero no previenen la infeccion o trasmision. Conclusiones. Problemas en el diagnostico de laboratorio de la leptospirosis conllevan a un sub-registro en el numero de casos; altas tasas de mortalidad asociadas a fallas renal y pulmonar son resultado de las dificultades en el manejo de los casos.

Vínculos de apego en niños víctimas de la violencia intrafamiliar.

Abstract: The objective of this investigation was to describe attachment relation that children who are victims of active or passive domestic violence establish with the people around them. The study was done with a sample of 27 children between the ages of 9 and 12, who live in sectors of levels 1 and 2 in Barranquilla. The Grounded Theory method of Glasser & Strauss (1967) was chosen for this investigation, and it was useful for establishing postures from the children’s interpretations of their attachment relation with their parents, caregivers or other people of their environment. Following these guidelines, a semi-structured interview was designed. It contained four categories of analysis: Con fi dence, Comprehension of Feelings, Intimacy and Availability. The results determined, in fi rst instance, the active presence of different people and contexts in the life of these children that go beyond the nuclear family. These subsidiary fi gures, like grandparents, uncles, cousins, brothers or sisters who play parental roles, friends, neighbors, and teachers, among others, are perceived as people who help them create a self-image, offer affection and con fi dence and look out for them. They help to mitigate the basic de fi ciencies of an inadequate relationship with parents. It was also found that children who were victims of active domestic violence perceive a greater rejection from their main caregivers than victims of passive domestic violence. This fact is related to a greater search for acceptance and demonstration of their worthiness from other fi gures, such as their friends or other adults