242 research outputs found

    Evaluación de los diferentes índices para cartografiar biocostras a partir de información espectral

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    Revista oficial de la Asociación Española de Teledetección[EN] Biological soil crusts (BSC) are complex communities formed by a close association of soil particles and cyanobacteria, algae, microfungi, lichens or bryophytes that live within or immediately on top of the uppermost millimeters of the soil surface. These communities cover non vegetated areas in most of the arid and semiarid ecosystems, and modify numerous soil surface properties and ecosystem processes. Given the importance of BSC in ecosystem functioning, accurate and spatially explicit information on the distribution of BSC is mandatory. With this objective, considerable effort has been devoted to identify and map BSC using remote sensing data, and some spectral indices have been developed. These indexes use the spectral differences among BSC and other surface components like vegetation or bare soil to identify the areas dominated by BSC. Our main objective is to test the feasibility of the previous indices published in the literature for mapping different types of BSC in a complex study area, where these index have not been developed, at different spatial scales. Our results showed the low capability of indexes based on multiespectral images to identify areas covered by BSCat field and image spatial scales. Hyperspetral indices, on the other hand, showed better results than those obtained with multispectral indices, with an accuracy around 71% because they analyzed specific absorption features related with photosynthetic pigments like chlorophyll and carotenoids. We can conclude that the spatial heterogeneity of the area and the spectral similarities among BSC, green and dry vegetation or bare soil makes it difficult to correctly distinguish BSC in arid and semiarid ecosystems using only multispectral information, whereas hyperspectral images offer an important tool to map different types of BSC and to discriminate among these and other surface components.[ES] Las biocostras o costras biológicas del suelo (CBS) son comunidades formadas por la asociación de partí-culas de suelo con microorganismos como cianobacterias, algas, hongos, líquenes, hepáticas o briófitos, que viven en la superficie del suelo. Estas comunidades bióticas cubren las áreas desprovistas de vegetación en los ecosistemas áridos y semiáridos, modificando las propiedades del suelo e influyendo en numerosos procesos clave para el funcio-namiento de los ecosistemas. Aunque representan una porción insignificante del perfil del suelo, las CBS regulan el intercambio de gases, agua y nutrientes desde y hacia el suelo, por lo que desempeñan un papel fundamental en los ecosistemas en los que aparecen. Debido al importante papel que ejercen las CBS en los ecosistemas donde aparecen y a su fragilidad frente a las acciones antrópicas, es necesario conocer de forma precisa su distribución espacial. Para ello, recientemente, se han desarrollado varios índices que permiten cartografiarlas a partir de imágenes obtenidas de sensores remotos. Este trabajo tiene por objetivo evaluar los diferentes índices desarrollados para cartografiar CBS, aplicándolos a una zona distinta para las que han sido desarrolladas. Los diferentes índices se evaluarán a dos escalas espaciales diferentes, parcela y ecosistema. A ambas escalas se analizará la fiabilidad de cada uno de los índices para la cartografía de CBS y su capacidad de diferenciar entre diferentes tipos, así como las principales cubiertas presentes en los sistemas áridos y semiáridos. La gran heterogeneidad espacial de la zona y la similitud espectral entre las CBS y la vegetación seca dificultan la correcta cartografía de ecosistemas en los que las CBS son una componente impor-tante utilizando información multiespectral. Sin embargo, los índices basados en información hiperespectral y alta resolución espacial constituyen una herramienta sólida para cartografiar CBS proporcionando una fiabilidad de 71%.Este trabajo ha sido cofinanciado por el proyecto COSTRAS (RNM 3614) de la Junta de Andalucía, y por el Ministerio de Ciencia y Tecnología a través del proyecto BACARCOS (CGL2011-29429), ambos cofinanciados con fondos FEDER. Los autores ademas agradecen al area de teledeteccion del INTA (Labtel) su inestimable ayAlonso, M.; Rodríguez-Caballero, E.; Chamizo, S.; Escribano, P.; Cantón, Y. (2014). Evaluation of the different spectral indices to map biocrust using spectral information. Revista de Teledetección. (42):79-98. https://doi.org/10.4995/raet.2014.2317SWORD79984

    Organization of Patient Management and Fungal Epidemiology in Cystic Fibrosis

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    The achievement of a better life for cystic fibrosis (CF) patients is mainly caused by a better management and infection control over the last three decades. Herein, we want to summarize the cornerstones for an effective management of CF patients and to give an overview of the knowledge about the fungal epidemiology in this clinical context in Europe. Data from a retrospective analysis encompassing 66,616 samples from 3235 CF patients followed-up in 9 CF centers from different European countries are shown

    Evaluation of frequency of antibodies against Toxoplasma gondii, Neospora caninum and Sarcocystis spp. and transmission routes in sheep from Humid Pampa, Argentina

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    The aim of this study was to describe the frequency of ovine specific antibodies to Toxoplasma gondii, Neospora caninum and Sarcocystis spp. and to estimate different transmission routes of these infections. One hundred and thirty Texel sheep and their 117 Texel lambs were included in the study. Serum samples were tested for antibodies to T. gondii, N. caninum and Sarcocystis spp. using IFAT. Toxoplasma gondii seroprevalence was 10.00% in sheep (IC95%: 4.80-15.20%), being higher in adult sheep (≥12 year) than in younger sheep (OR 1.30; 95% CI, 1.10-1.50). N. caninum and Sarcocystis spp. seroprevalences were 1.54% (IC95%: 0.00-5.70) and 72.09% (IC95%: 67.70-82.70), respectively, with no association between age and seropositivity in sheep (P>0.05). T. gondii seroprevalence in lambs was 4.27% (IC95%: 0.61-7.94). No association between T. gondii serological status in sheep and their lambs was detected (P = 0.07). Two T. gondii and Sarcocystis spp. seropositive lambs were euthanized and T. gondii and Sarcocystis spp. DNA was detected by PCR in their tissues. In conclusion, the increase of T. gondii seropositivity in relationship with sheep age and the lack of association between sheep-lamb serological status, suggest that horizontal infection is the main transmission route in this flock as reported before. Due to the low number of N. caninum-seropositive ewes no assumptions can be done about the impact of this parasite in this flock. According with previous reports, the main transmission route for Sarcocystis spp. in this species in the present study was horizontal.Facultad de Ciencias Veterinaria

    Real Time QRS Detection Based on M-ary Likelihood Ratio Test on the DFT Coefficients

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    This paper shows an adaptive statistical test for QRS detection of electrocardiography (ECG) signals. The method is based on a M-ary generalized likelihood ratio test (LRT) defined over a multiple observation window in the Fourier domain. The motivations for proposing another detection algorithm based on maximum a posteriori (MAP) estimation are found in the high complexity of the signal model proposed in previous approaches which i) makes them computationally unfeasible or not intended for real time applications such as intensive care monitoring and (ii) in which the parameter selection conditions the overall performance. In this sense, we propose an alternative model based on the independent Gaussian properties of the Discrete Fourier Transform (DFT) coefficients, which allows to define a simplified MAP probability function. In addition, the proposed approach defines an adaptive MAP statistical test in which a global hypothesis is defined on particular hypotheses of the multiple observation window. In this sense, the observation interval is modeled as a discontinuous transmission discrete-time stochastic process avoiding the inclusion of parameters that constraint the morphology of the QRS complexes.This work has received research funding from the Spanish government (www.micinn.es) under project TEC2012 34306 (DiagnoSIS, Diagnosis by means of Statistical Intelligent Systems, 70K€) and projects P09-TIC-4530 (300K€) and P11-TIC-7103 (156K€) from the Andalusian government (http://www.juntadeandalucia.es/organismo​s/economiainnovacioncienciayempleo.html)

    Encephalopathy associated with autoimmune thyroid disease in patients with Graves' disease: clinical manifestations, follow-up, and outcomes

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    <p>Abstract</p> <p>Background</p> <p>The encephalopathy associated with autoimmune thyroid disease (EAATD) is characterized by neurological/psychiatric symptoms, high levels of anti-thyroid antibodies, increased cerebrospinal fluid protein concentration, non-specific electroencephalogram abnormalities, and responsiveness to the corticosteroid treatment in patients with an autoimmune thyroid disease. Almost all EAATD patients are affected by Hashimoto's thyroiditis (HT), although fourteen EAATD patients with Graves' disease (GD) have been also reported.</p> <p>Methods</p> <p>We have recorded and analyzed the clinical, biological, radiological, and electrophysiological findings and the data on the therapeutic management of all GD patients with EAATD reported so far as well as the clinical outcomes in those followed-up in the long term.</p> <p>Results</p> <p>Twelve of the fourteen patients with EAATD and GD were women. The majority of GD patients with EAATD presented with mild hyperthyroidism at EAATD onset or shortly before it. Active anti-thyroid autoimmunity was detected in all cases. Most of the patients dramatically responded to corticosteroids. The long term clinical outcome was benign but EAATD can relapse, especially at the time of corticosteroid dose tapering or withdrawal. GD and HT patients with EAATD present with a similar clinical, biological, radiological, and electrophysiological picture and require an unaffected EAATD management.</p> <p>Conclusions</p> <p>GD and HT equally represent the possible background condition for the development of EAATD, which should be considered in the differential diagnosis of all patients with encephalopathy of unknown origin and an autoimmune thyroid disease, regardless of the nature of the underlying autoimmune thyroid disease.</p

    Immune response to Neospora caninum live tachyzoites in prepubertal female calves

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    The aim of the present study was to characterize the specific immune response in prepubertal female calves inoculated with Neospora caninum. Forty-eight N. caninum-seronegative 6-month-old Angus female calves were randomly allocated into two groups: group A calves were inoculated subcutaneously (sc) with 1 × 106 tachyzoites of the low virulence NC-Argentina LP1 isolate in sterile phosphate-buffered saline (PBS); group B calves were mock inoculated sc with sterile PBS. Calves from group A developed a specific immune response characterized by the production of IgG antibodies and the expression of IFN-γ and TNF-α cytokines. Animals did not present any febrile reaction or reactions at the site of inoculation. Although chronic N. caninum infection was developed in 50% of calves of group A after inoculation, according to the presence of antibodies against rNc-SAG4, antigen characteristic of bradyzoites, N. caninum antibodies dropped below the cut-off of ELISA from day 210 post-inoculation onwards. Future trials using the same group of inoculated animals will allow the characterization of the evolution of the immune response during pregnancy and to determine whether the immunization with the local isolate is able to prevent congenital transmission and to protect against heterologous challenges.Facultad de Ciencias Veterinaria
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