Natural transmission of Leishmania infantum through experimentally infected Phlebotomus perniciosus highlights the virulence of Leishmania parasites circulating in the human visceral leishmaniasis outbreak in Madrid, Spain

A human leishmaniasis outbreak is occurring in the Madrid region, Spain, with the parasite and vector involved being Leishmania infantum and Phlebotomus perniciosus respectively. The aim of this study was to investigate the virulence of L. infantum isolates from the focus using a natural transmission model. Hamsters were infected by intraperitoneal inoculation (IP) or by bites of sand flies experimentally infected with L. infantum isolates obtained from P. perniciosus collected in the outbreak area (IPER/ES/2012/BOS1FL1 and IPER/ES/2012/POL2FL6) and a well characterized L. infantum strain JPCM5 (MCAN/ES/98/LLM-877). Hamster infections were monitored by clinical examination, serology, culture, parasite burden, Giemsa-stained imprints, PCR, histopathology and xenodiagnostic studies. Establishment of infection of L. infantum was achieved with the JPCM5 strain and outbreak isolates by both P. perniciosus infective bites or IP route. However, high virulence of BOS1FL1 and POL2FL6 isolates was highlighted by the clinical outcome of disease, high parasite detection in spleen and liver, high parasitic loads and positivity of Leishmania serology. Transmission by bite of POL2FL6 infected flies generated a slower progression of clinical disease than IP infection, but both groups were infective to P. perniciosus by xenodiagnosis at 2 months post-infection. Conversely, hamsters inoculated with JPCM5 were not infective to sand flies. Histopathology studies confirmed the wide spread of POL2FL6 parasites to several organs. A visceral leishmaniasis model that mimics the natural transmission in nature allowed us to highlight the high virulence of isolates that are circulating in the focus. These findings contribute to a better understanding of the outbreak epidemiology.This study was partially funded by the Spanish Ministry of Science & Innovation (Project AGL2008‑01592) and by the EU grant FP7‑2011‑261504 EDENext. The paper is catalogued by the EDENext Steering Committee as EDENext372. We would like to thank the Veterinary Unit (ISCIII) for animal handling, Histopathology Unit (ISCIII) for histology sections preparation, Sonia Hernández for excellent sand fly rearing and Ancare Velasco for technical work. We would like to dedicate this work to the memory of Cesar Eguiluz who sadly passed away during the course of revision of this paper.S

Isotropic extensions of the vacuum solutions in general relativity

In this work, we obtain isotropic extensions of the usual spherically symmetric vacuum geometries in general relativity. Exact and perturbative solutions are derived. The classes of geometries obtained include black holes in compact and noncompact universes, wormholes in the interior region of cosmological horizons, and anti-de Sitter geometries with excess/deficit solid angle. The tools developed here are applicable in more general contexts.Comment: 12 pages, 6 figures. Version to be published in Physical Review

CRiSOL: Opinion Knowledge-base for Spanish

El presente trabajo se centra en la clasificación de polaridad de comentarios de hoteles en español (COAH) y presenta un nuevo recurso léxico, CRiSOL. Este nuevo recurso toma como base la lista de palabras de opinión iSOL, a la cual incluye los valores de polaridad de los synsets de SentiWordNet. Debido a que SentiWordNet no es un recurso para español, se ha tenido que usar como pivote la versión española de WordNet incluida en el Repositorio Central Multilingüe (MCR). Se ha desarrollado un clasificador de la polaridad no supervisada para evaluar la validez de CRiSOL. Los resultados obtenidos con CRiSOL superan los obtenidos por los lexicones base iSOL y SentiWordNet por separado, lo cual nos anima a seguir trabajando en esta línea.In this paper we focus on Spanish polarity classification in a corpus of hotel reviews (COAH) and we introduce a new lexical resource called CRiSOL. This new resource is built on the list of Spanish opinion words iSOL. CRiSOL appends to each word of iSOL the polarity value of the related synset of SentiWordNet. Due to the fact that SentiWordNet is not a Spanish linguistic resource, a Spanish version of WordNet had to be used. The Spanish version of WordNet chosen was Multilingual Central Repository (MCR). An unsupervised classifier has been developed with the aim of assessing the validity of CRiSOL. The results reached by CRiSOL are higher than the ones reached by iSOL and SentiWordNet, so that encourage us to continue this research line.Esta investigación ha sido parcialmente financiada por el Fondo Europeo de Desarrollo Regional (FEDER), el proyecto ATTOS (TIN2012-38536-C03-0) del Gobierno de España y el proyecto AORESCU (P11-TIC-7684 MO) del gobierno autonómico de la Junta de Andalucía. Por último, el proyecto CEATIC (CEATIC-2013-01) de la Universidad de Jaén también ha financiado parcialmente este artículo

Identificando actividades de matematización horizontal y vertical en un proceso de clasificación

La noción de matematización progresiva se expresa través de una secuencia generada por dos tipos de actividad matemática relacionadas reflexivamente: la matematización horizontal y la vertical (Treffers, 1987). Aunque, frecuentemente, la matematización horizontal se describe a través de la transformación de una situación problemática en un problema matemático propiamente dicho, en nuestro trabajo utilizaremos este concepto en un sentido más amplio que nos permitirá incluir situaciones de partida que sean de naturaleza ya matemática (Rasmussen, Zandieh, King & Teppo, 2005). Las actividades que pueden ser identificadas cuando se produce la matematización horizontal y la matematización vertical han sido descritas por Üzel y Mert Uyangör (2006)

Extreme cycles. The center of a Leavitt path algebra

In this paper we introduce new techniques in order to deepen into the structure of a Leavitt path algebra with the aim of giving a description of the center. Extreme cycles appear for the first time; they concentrate the purely infinite part of a Leavitt path algebra and, jointly with the line points and vertices in cycles without exits, are the key ingredients in order to determine the center of a Leavitt path algebra. Our work will rely on our previous approach to the center of a prime Leavitt path algebra