59 research outputs found

    Dynamics of organic carbon losses by water erosion after biocrust removal

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    In arid and semiarid ecosystems, plant interspaces are frequently covered by communities of cyanobacteria, algae, lichens and mosses, known as biocrusts. These crusts often act as runoff sources and are involved in soil stabilization and fertility, as they prevent erosion by water and wind, fix atmospheric C and N and contribute large amounts of C to soil. Their contribution to the C balance as photosynthetically active surfaces in arid and semiarid regions is receiving growing attention. However, very few studies have explicitly evaluated their contribution to organic carbon (OC) lost from runoff and erosion, which is necessary to ascertain the role of biocrusts in the ecosystem C balance. Furthermore, biocrusts are not resilient to physical disturbances, which generally cause the loss of the biocrust and thus, an increase in runoff and erosion, dust emissions, and sediment and nutrient losses. The aim of this study was to find out the influence of biocrusts and their removal on dissolved and sediment organic carbon losses. One-hour extreme rainfall simulations (50 mm h-1) were performed on small plots set up on physical soil crusts and three types of biocrusts, representing a development gradient, and also on plots where these crusts were removed from. Runoff and erosion rates, dissolved organic carbon (DOC) and organic carbon bonded to sediments (SdOC) were measured during the simulated rain. Our results showed different SdOC and DOC for the different biocrusts and also that the presence of biocrusts substantially decreased total organic carbon (TOC) (average 1.80±1.86 g m-2) compared to physical soil crusts (7.83±3.27 g m-2). Within biocrusts, TOC losses decreased as biocrusts developed, and erosion rates were lower. Thus, erosion drove TOC losses while no significant direct relationships were found between TOC losses and runoff. In both physical crusts and biocrusts, DOC and SdOC concentrations were higher during the first minutes after runoff began and decreased over time as nutrient-enriched fine particles were washed away by runoff water. Crust removal caused a strong increase in water erosion and TOC losses. The strongest impacts on TOC losses after crust removal occurred on the lichen plots, due to the increased erosion when they were removed. DOC concentration was higher in biocrust-removed soils than in intact biocrusts, probably because OC is more strongly retained by BSC structures, but easily blown away in soils devoid of them. However, SdOC concentration was higher in intact than removed biocrusts associated with greater OC content in the top crust than in the soil once the crust is scraped off. Consequently, the loss of biocrusts leads to OC impoverishment of nutrient-limited interplant spaces in arid and semiarid areas and the reduction of soil OC heterogeneity, essential for vegetation productivity and functioning of this type of ecosystems.This work was partially supported by several research projects: COSTRAS (RNM 3614), funded by the Consejería de Innovación, Ciencia y Empresa (Junta de Andalucía) including ERD (European Union of Regional Development) Funds, BACARCOS (CGL2011–29429) funded by Spanish national Plan for Research, Development and Innovation and including European Union of Regional Development Funds ERDF funds

    RoboARCH: An autonomous robot for analysis and documentation of historical architectures

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    The Mediterranean basin has an impressive amount of millenarian urban structures which have been modelled along centuries. Unfortunately, they are sometimes damaged due to both the passage of time as well as bad preservation criteria. In order to avoid these situations or reduce their effects, new preservation criteria have arisen in the last decades. These criteria aim to revitalize the historical value of these architectural remains from a cultural and economic perspective. In this line of research, the “Archaeology of Architecture” applies the theoretical principles of the archaeology to study buildings and streets, offering new methodologies of analysis. An important part of these methodologies incorporates new technologies, such as 3D scanners, robotic total stations, or virtual and augmented reality, to the data acquisition and processing tasks. The application of these technologies in the area of Historical Heritage results in a breakthrough in the graphic documentation of monuments and archaeological remains, which allows the development of new preservation strategies. Among all these new technologies, this abstract proposes the use of an autonomous robot to help identifying elements inside a building. The robot navigates through the environment, collects data and compares them against well-known historical and architectural archetypes, to find a set of candidates for each perceived pattern. The advantages of the proposed system when compared against current state-of-the-art techniques are the following: (i) the robot explores the environment autonomously using SLAM (Simultaneous Localization And Mapping) algorithms and acquires colour and depth information; (ii) no special markers, such as the targets or spheres usually employed by robotic total stations, are required; (iii) the system uses advanced image processing methods to automatically provide a first characterization of perceived borders, that will help in different identification processes, from single elements to more complex structures; (iv) obtained data are compared against historical and architectural archetypes included in a data base; (v) evaluation of the object position inside the stratigraphic sequence of the wall.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Afecciones de hemangiomas cutáneos en la infancia registrados en Villa Clara desde 2012 hasta 2015

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    Introducción: los hemangiomas son el tumor cutáneo más común en la infancia. Se clasifican dentro de las anomalías vasculares congénitas.Objetivo: identificar el comportamiento clínico-epidemiológico y resultados terapéuticos de los hemangiomas en pacientes atendidos en el Hospital Infantil “José Luis Miranda” de Santa Clara, Villa Clara en el período 2012-2015. Materiales y Métodos: se empleó el método bibliométrico y técnicas de visualización y representación de información. El estudio clasifica como descriptivo de tipo longitudinal retrospectivo. El universo lo constituyó todos los niños con hemangiomas cutáneos atendidos en el Hospital Infantil “José Luis Miranda”, de Villa Clara. Las variables que se analizaron fueron: edad, tipo de lesión, localización, complicaciones, afecciones por sexo, raza, antecedentes familiares del padecimiento, así como el tratamiento prescripto y su evaluación. Resultados: se determinaron las afecciones por raza, edad, sexo y antecedentes familiares de los infantes. Se estudiaron las lesiones por tipos y complicaciones. El comportamiento de las afecciones de hemangiomas cutáneos en la infancia registrada en Villa Clara, entre los años 2012 y 2015, coincide con criterios descritos por varios especialistas e investigadores de esta afección. Conclusiones: se corroboró que el sexo femenino, niños menores de 1 año y de piel blanca, fueron los pacientes afectados con mayor regularidad. Se identificó que las lesiones se localizaron con mayor frecuencia en cara, cuero cabelludo y tronco. Los tratamientos más efectivos fueron la cirugía, electrodesecación y los esteroides locales y sistémicos

    Vasculitis leucocitoclástica

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    Introducción: la vasculitis leucocitoclástica constituye un proceso clínico patológico caracterizado por inflamación y necrosis de los vasos sanguíneos. Objetivo: describir las características clínicas de la vasculitis leucocitoclástica y el tratamiento utilizado. Resultados: se indicaron estudios de laboratorios: eritrosedimentación, células LE I, II y III, factor reumatoide, exudado faríngeo, U.S.A y biopsia de piel; arrojando este último vasculitis leucocitoclástica. Conclusiones: la vasculitis leucocitoclástica se conoce con el nombre de venulitis cutánea necrotizante y ocurre en asociación a enfermedades crónicas, puede ser precipitada por infecciones o drogas y desarrollarse por causa desconocida. Los fármacos y agentes terapéuticos que se describen son: penicilina, sulfonamida, tiamina, hidantoina, alopurinol, hidralazina propiltiuracilo y después de la estreptoquinaza recombinante, anticuerpos monoclonales y radioterapia

    Deficiency in p53 is required for doxorubicin induced transcriptional activation of NF-кB target genes in human breast cancer

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    NF-кB has been linked to doxorubicin resistance in breast cancer patients. NF- кB nuclear translocation and DNA binding in doxorubicin treated-breast cancer cells have been extensively examined; however its functional relevance at transcriptional level on NF-кB -dependent genes and the biological consequences are unclear. We studied NF-кB -dependent gene expression induced by doxorubicin in breast cancer cells and fresh human cancer specimens with different genetic backgrounds focusing on their p53 status. NF-кB –dependent signature of doxorubicin was identified by gene expression microarrays in breast cancer cells treated with doxorubicin and the IKKβ-inhibitor MLN120B, and confirmed ex vivo in human cancer samples. The association with p53 was functionally validated. Finally, NF-кB activation and p53 status was determined in a cohort of breast cancer patients treated with adjuvant doxorubicin-based chemotherapy. Doxorubicin treatment in the p53-mutated MDA-MB-231 cells resulted in NF NF- кB driven-gene transcription signature. Modulation of genes related with invasion, metastasis and chemoresistance (ICAM-1, CXCL1, TNFAIP3, IL8) were confirmed in additional doxorubicin-treated cell lines and fresh primary human breast tumors. In both systems, p53-deficient background correlated with the activation of the NF-кB –dependent signature. Furthermore, restoration of p53WT in the mutant p53 MDAMB- 231 cells impaired NF-кB driven transcription induced by doxorubicin. Moreover, a p53 deficient background and nuclear NF-кB /p65 in breast cancer patients correlated with reduced disease free-survival. This study supports that p53 deficiency is necessary for a doxorubicin driven NF-кB -response that limits doxorubicin cytotoxicity in breast cancer and is linked to an aggressive clinical behavior.Financial support: This work was supported by RD12/0036/0051 (J.A.), RD09/0076/0101, RD09/0076/0036, RD12/0036/0054 (A.B), RD12/0036/0070 (A. Ll), PI12/00680 (J.A.), PI12/01552 (F.R.), PI12/01421 (A.Ll.), 2009 SGR 321 (J.A.), FMM 9757/002 (F.R.), and the “Xarxa de Bancs de tumors sponsored by Pla Director d’Oncologia de Catalunya (XBTC). J.A. and F.R. are recipients of intensification program ISCIII/FEDER. We thank Fundació Cellex (Barcelona) for a generous donation to the Hospital del Mar Medical Oncology Service. We thank Millenium for generously providing MLN120B

    Coupling sewage sludge amendment with cyanobacterial inoculation to enhance stability and carbon gain in dryland degraded soils

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    Sewage sludge (SS) is widely used as a soil conditioner in agricultural soil due to its high content of organic matter and nutrients. In addition, inoculants based on soil microorganisms, such as cyanobacteria, are being applied successfully in soil restoration to improve soil stability and fertility in agriculture. However, the combination of SS and cyanobacteria inoculation is an unexplored application that may be highly beneficial to soil. In this outdoor experiment, we studied the ability of cyanobacteria inoculum to grow on degraded soil amended with different concentrations of composted SS, and examined the effects of both SS concentration and cyanobacteria application on carbon gain and soil stability. We also explored the feasibility of using cyanobacteria for immobilizing salts in SS-amended soil. Our results showed that cyanobacteria growth increased in the soil amended with the lowest SS concentration tested (5 t ha−1, on soil 2 cm deep), as shown by its higher chlorophyll a content and associated deeper spectral absorption peak at 680 nm. At higher SS concentrations, inoculum growth decreased, which was attributed to competition of the inoculated cyanobacteria with the native SS bacterial community. However, SS significantly enhanced soil organic carbon gain and tightly-bound exopolysaccharide content. Cyanobacteria inoculation significantly improved soil stability and reduced soil’s wind erodibility. Moreover, it led to a decrease in the lixiviate electrical conductivity of salt-contaminated soils, indicating its potential for salt immobilization and soil bioremediation. Therefore, cyanobacteria inoculation, along with adequately dosed SS surface application, is an efficient strategy for improving carbon gain and surface stability in dryland agricultural soil

    Polyphasic evaluation of key cyanobacteria in biocrusts from the most arid region in Europe

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    Cyanobacteria are key microbes in topsoil communities that have important roles in preventing soil erosion, carbon and nitrogen fixation, and influencing soil hydrology. However, little is known regarding the identity and distribution of the microbial components in the photosynthetic assemblages that form a cohesive biological soil crust (biocrust) in drylands of Europe. In this study, we investigated the cyanobacterial species colonizing biocrusts in three representative dryland ecosystems from the most arid region in Europe (SE Spain) that are characterized by different soil conditions. Isolated cyanobacterial cultures were identified by a polyphasic approach, including 16S rRNA gene sequencing, phylogenetic relationship determination, and morphological and ecological habitat assessments. Three well-differentiated groups were identified: heterocystous-cyanobacteria (Nostoc commune, Nostoc calcicola, Tolypothrix distorta and Scytonema hyalinum), which play an important role in N and C cycling in soil; nonheterocystous bundle-forming cyanobacteria (Microcoleus steenstrupii, Trichocoleus desertorum, and Schizothrix cf. calcicola); and narrow filamentous cyanobacteria (Leptolyngbya frigida and Oculatella kazantipica), all of which are essential genera for initial biocrust formation. The results of this study contribute to our understanding of cyanobacterial species composition in biocrusts from important and understudied European habitats, such as the Mediterranean Basin, a hotspot of biodiversity, where these species are keystone pioneer organisms
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