3,333 research outputs found

    Diversity of N2-fixing cyanobacteria from Andalusian paddy fields and analysis of their potential as bioinoculants

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    The marshes of the Guadalquivir River contain the largest area of rice cultivation in Spain, where more than 40,000 ha are used every year for rice production. These wetland areas provide a perfect place for rice cultivation, and represent a unique aquaticterrestrial habitat that hold more wintering waterfowl than any other European wetland. Paddies require large amounts nitrogen and phosphorus for their growth, development and production. Though, flooded conditions used for rice cultivation drastically diminish efficiency inorganic nitrogen fertilizers, being only 30–40% used by the plant, and in some cases even less. Large amounts of nitrogen fertilizers are dissolved in the surface water and lost, causing environmental pollution and health problems due to losses through N2O and NO volatilization, denitrification, and leaching (Ishii et al., 2011)

    Simulación mediante ordenador de movimientos bidimensionales en medios resistentes

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    We have accomplished a simulation program of mechanics; it is developed in laboratory practice by students in their first years of physics studies ata University level. Its aim is a better understanding of the influence of the variable forces of friction in bidimensional movements. We have verified the effectiveness of this teaching method through the evaluation of the students' progress during the courses in which we have carried out this practice

    Drawing the Architectural Heritage on the Coast of the Mediterranean (1936-39)

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    During the civil war (1936-39) was built a network of defensive settlements on the coast in anticipation of attacks enemies, forming the so-called 'wall Mediterranean', because of its similarity with the Wall Atlantic of the World War II. These enclaves were composed of groups of batteries, bunkers and buildings. This communication comes to inventory and draw the remains of more than 50 architectures that are located in the Valencian South Coast (from Denia to Torrevieja), documenting the first ruins of hormigion armed with our history. It's a set of military settlements anti-aircraft, mostly scattered coastal rural, which are a great heritage and landscape value, and from which planes haven't been preserved. It is to lift current state record of them all, proceeding to its typological classification, in order to contribute to its assessment and protection on the grounds that they constitute a legacy of architectural heritage that increases our cultural memory.history

    Comunidades de hongos endófitos en plantaciones de pino y robledales del norte de España

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    Replacement of native forest with plantations of other species can have important consequences over the ecosystem. Some of these changes have been widely studied, but very little information is available about what happen with fungal communities and specifically with endophyte species living there. In this work endophyte assemblages of pine plantations (Pinus sylvestris, P. nigra and P. pinaster) are compared with those found in the original oak forest (Quercus pyrenaica) of the study area (north of Palencia province, Spain). For this purpose, samples of needles/leaves and twigs from three trees in each one of the three plots sampled per host species, were first collected and later processed in the lab to detect all endophyte species living there. Besides an intensive data compilation was realized in the twelve sites studied to analyze the environmental, crown condition, dendrometric and soil variables involved in the distribution of the fungi. Endophyte assemblages of P. nigra and P. sylvestris resulted to be closer, and at the same time separated from the ones of P. pinaster and Q. pyrenaica. In addition, some variables were found to be related to the endophyte communities’ distribution. Finally, a change in the endophyte communities was detected due to the deterioration and replacement of native oak forests with pine plantations.La sustitución de los bosques autóctonos por plantaciones de otras especies puede tener importantes consecuencias sobre el ecosistema. Algunos de esos cambios ya han sido ampliamente estudiados, pero hasta el momento hay muy poca información acerca de lo que ocurre con las comunidades fúngicas y en especial con las de los endófitos que ahí viven. En este trabajo se analizaron las agrupaciones de endófitos existentes en las plantaciones de pino (Pinus sylvestris, P. nigra y P. pinaster) y bosques nativos de rebollo (Quercus pyrenaica) en el norte de la provincia de Palencia (España). Para ello se recogieron muestras de acículas/hojas y ramillos de cada una de las especies estudiadas que fueron procesadas en laboratorio para determinar qué especies de hongos endófitos portaban. Además se realizó una exhaustiva toma de datos en las doce parcelas estudiadas para analizar las variables ambientales, del estado fitosanitario de la copa, dendrométricas y edáficas implicadas en la distribución de los hongos. Las comunidades de endófitos encontradas en P. sylvestris y P. nigra resultaron ser similares entre sí, y al mismo tiempo diferentes de las de P. pinaster. Los endófitos aparecidos sobre Q. pyrenaica resultaron estar alejados de los del resto de los hospedantes, por lo que la conservación de los robledales es importante para evitar la pérdida de la diversidad fúngica. Finalmente se encontraron algunas variables ambientales relacionadas con la distribución de las comunidades de endófitos

    Large N expansions and Painlev\'e hierarchies in the Hermitian matrix model

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    We present a method to characterize and compute the large N formal asymptotics of regular and critical Hermitian matrix models with general even potentials in the one-cut and two-cut cases. Our analysis is based on a method to solve continuum limits of the discrete string equation which uses the resolvent of the Lax operator of the underlying Toda hierarchy. This method also leads to an explicit formulation, in terms of coupling constants and critical parameters, of the members of the Painlev\'e I and Painlev\'e II hierarchies associated with one-cut and two-cut critical models respectively

    Nueva forma de entender las pruebas de condición física en relación con la salud

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    El objetivo de este trabajo es mostrar una nueva forma de entender la evaluación de la “condición física en relación con la salud”, para evitar la inactividad y el sedentarismo. Los antecedentes se encuentran en las baterías de test utilizadas desde 1976 hasta la actualidad. Se utiliza el concepto de salud de la OMS. Se analizan pruebas con criterios de funcionalidad, economía, validez, fiabilidad y especificidad. Se eligen las siguientes pruebas y se calculan los umbrales: UKK Walk test (P75), 6” en sprint test 20 m (P75), 19 repeticiones en Chair Stand Test(P25), 11 repeticiones Arm Curl Test (P25), -10,5 cm Back Scratch Test (P25), -17,5 cm en Chair Sit and Reach Test. Se propugna la elaboración de una batería de test universal e inclusiva y elaborar percentiles mundiales ayudados por el big dataThe aim of this research was to propose a new way of understanding health-related physical fitness assessment in order to prevent inactivity and sedentarism. The background lies in the test batteries used from 1976 to the present. WHO's health concept was used. Tests were analysed based on functionality, economy, validity, reliability and specificity criteria. The following tests were chosen and the thresholds were calculated: 1,425s in the UKK walk test (P75), 6s in the 20-m sprint test (P75), 19 repetitions in the chair stand test (P25), 11 repetitions in the arm curl test (P25), -10.5cm in the back scratch test (P25), -17.5cm in the chair sit-and-reach test (P25). It was proposed that a universal and inclusive test battery be developed and the percentiles for the world population are determined with the help of big dat

    Diversity of N2-fixing cyanobacteria from Andalusian paddy fields and analysis of their potential as bioinoculants

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    The marshes of the Guadalquivir River contain the largest area of rice cultivation in Spain, where more than 40,000 ha are used every year for rice production. These wetland areas provide a perfect place for rice cultivation, and represent a unique aquatic-terrestrial habitat that hold more wintering waterfowl than any other European wetland.Paddies require large amounts nitrogen and phosphorus for their growth, development and production. Though, flooded conditions used for rice cultivation drastically diminish efficiency inorganic nitrogen fertilizers, being only 30–40% used by the plant, and in some cases even less. Large amounts of nitrogen fertilizers are dissolved in the surface water and lost, causing environmental pollution and health problems due to losses through N2O and NO volatilization, denitrification, and leaching (Ishii et al., 2011).The paddy field ecosystem provides a favourable environment for the growth of phototrophic microorganisms including nitrogen-fixing cyanobacteria, as it meets their requirements for light, water, temperature and nutrient availability. The ability of this type of cyanobacteria to fix N2 provides a natural source of fixed nitrogen to the plant that is evidently priceless, and encourages research to develop new cyanobacteria-based biofertilizers for rice cultivation. In our laboratory, diversity of N2-fixing cyanobacteria from Andalusian paddies has been studied by means of metagenomic analysis and classical microbiological approaches. We have found that agronomic techniques influence microbial diversity (Ramírez-Moncayo et al., 2018). We have also isolated Nitrogen-fixing cyanobacteria from the paddy fields and we have found that Nostocaceae and Rivulariaceae are the dominant N2-fixing cyanobacteria families in these isolates (Alves-Martínez et al., 2017). Genetic analysis of the different isolates revealed the presence of new uncharacterized strains. We have evaluated their potential as bioinoculants for plant fortification. Some of the strains showed a strong attraction and attachment to rice roots, which could be an indication of possible supply to the plant of nitrogen-fixed metabolites by the cyanobacterium. These isolates might be used for the formulation of new ecological biofertilizers alternative to chemical synthetic fertilizers

    Efecto de la poda en plantaciones de pino radiata afectadas por Fusarium circinatum

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    Fusarium circinatum Nirenberg and O’Donnell (1998) is the causal agent of Pitch Canker Disease (PCD) in Pinus species, producing damage to the main trunk and lateral branches as well as causing branch dieback. The disease has been detected recently in northern Spain in Pinus spp. seedlings at nurseries and in Pinus radiata D. Don adult trees in plantations. Fusarium circinatum seems to require a wound to enter the tree, not only that as caused by insects but also that resulting from damage by humans, i.e. mechanical wounds. However, the effects of pruning on the infection process have yet to be studied. The aim of the present study was to know how the presence of mechanical damage caused by pruning affects PCD occurrence and severity in P. radiata plantations. Fifty P. radiata plots (pruned and unpruned) distributed throughout 16 sites affected by F. circinatum in the Cantabria region (northern Spain) were studied. Symptoms of PCD presence, such as dieback, oozing cankers and trunk deformation were evaluated in 25 trees per plot and related to pruning effect. A significant relationship between pruning and the number of cankers per tree was observed, concluding that wounds caused by pruning increase the chance of pathogen infection. Other trunk symptoms, such as the presence of resin outside the cankers, were also higher in pruned plots. These results should be taken into account for future management of Monterrey Pine plantations.Fusarium circinatum Nirenberg and O’Donnell (1998) es el agente causante de la enfermedad del chancro resinoso del pino, que afecta a especies del género Pinus y provoca la aparición de chancros resinosos en el tronco y en ramas gruesas, además de puntisecado en la guía terminal. Esta enfermedad fue detectada recientemente en el norte de España asociada a plántulas de coníferas en vivero y a plantaciones de Pinus radiata D. Don. Fusarium circinatum suele requerir una herida en el árbol para poder infectarlo. Estas heridas pueden estar causadas por insectos o ser de origen antrópico, como las heridas mecánicas. Con la finalidad de conocer cómo las heridas producidas durante la poda afectan a la severidad de la enfermedad del chancro resinoso del pino, se estudiaron 50 parcelas de P. radiata (podadas y no podadas) distribuidas a lo largo de la provincia de Cantabria. En cada una de las parcelas fueron evaluados 25 árboles, en los que se estudiaron los síntomas más característicos de la enfermedad, como son puntisecado, presencia de chancros resinosos y deformación del tronco, relacionándolos con la presencia de poda. Se observó una relación significativa entre la poda y el número de chancros presentes en el árbol, lo que indica que la herida producida en este tratamiento selvícola es susceptible de infección por parte del patógeno. Otros síntomas también presentes en el tronco, como los exudados de resina fuera del chancro, aparecieron más frecuentemente en las parcelas podadas. Estos resultados son de gran trascendencia para el futuro manejo de las plantaciones de P. radiata afectadas por el chancro resinoso del pino
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