55 research outputs found

    Linking soil microbial community structure to potential carbon mineralization: A continental scale assessment of reduced tillage

    Get PDF
    Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal community structure and potential microbial drivers of Cmin in soils maintained under various degrees of physical disturbance. Potential carbon mineralization, 16S rRNA sequences, and soil characterization data were collected as part of the North American Project to Evaluate Soil Health Measurements (NAPESHM). Results showed that type of cropping system, intensity of physical disturbance, and soil pH influenced microbial sensitivity to physical disturbance. Furthermore, 28% of amplicon sequence variants (ASVs), which were important in modeling Cmin, were enriched under soils managed with minimal physical disturbance. Sequences identified as enriched under minimal disturbance and important for modeling Cmin, were linked to organisms which could produce extracellular polymeric substances and contained metabolic strategies suited for tolerating environmental stressors. Understanding how physical disturbance shapes microbial communities across climates and inherent soil properties and drives changes in Cmin provides the context necessary to evaluate management impacts on standardized measures of soil microbial activity

    Natural history of G ynaikothrips uzeli (Thysanoptera, Phlaeothripidae) in galls of Ficus benjamina (Rosales, Moraceae)

    Get PDF
    ABSTRACT Galls induced by thrips are simple structures when compared to those of other groups of arthropods, and little is known regarding many of their aspects. This study aimed to investigate aspects of the natural history of Gynaikothrips uzeli Zimmermann, 1900 in galls of Ficus benjamina L., 1753 using seasonal sampling (summer and winter). Twenty trees were sampled and divided into quadrants. From each of them, five galls were collected, forming a total of 400 galls per collection. Thrips showed greater abundance at higher temperatures (25.7°C) and no precipitation. Sex ratio was biased towards females (0.022 males per female), pointing to an inbred mating structure. Arthropod fauna associated with galls was more abundant (N=798) in winter, and it included representatives of the orders Hemiptera, Hymenoptera, Araneae, Coleoptera, Neuroptera, Psocoptera, Thysanoptera, Diptera and Blattodea

    Comportamiento alimentario de Frankliniella occidentalis (Pergande) y la incidencia de TSWV (Tomato Spotted Wild Virus) en plantas de papa del cultivar Innovator

    No full text
    Los objetivos de este trabajo son: analizar el comportamiento de alimentación de las hembras de Frankliniella occidentalis confinadas individualmente en discos de hoja de papa de seis cultivares y comprobar y comparar la transmisión de TSWV por F. occidentalis a los cultivares de papa Spunta e Innovator con la finalidad de encontrar una posible causa que pueda explicar la mayor incidencia de TSWV en cultivos de papa del cultivar Innovator. La habilidad de transmitir TSWV fue evaluada en cultivares de papa Spunta e Innovador. Se realizaron pruebas de preferencia de alimentación por Frankliniella occidentalis. Se colocaron hembras adultas de F. occidentalis individualmente y se evaluó la alimentación en seis cultivares de papa. Se contó el número de gotitas fecales por disco de hojas. Los vectores se alimentaban significativamente menos en discos de hojas del cultivar Innovator que en otros cultivares. El porcentaje de discos de hojas de papa positivo para TSWV en Innovator fue superior al de Spunta. Las hembras transmitieron con la misma eficiencia que los machos en Innovator y menos eficientemente en Spunta. Es probable que se produzcan menos daños en las células de Innovator debido a una menor ingesta y probablemente mayor número de pruebas de hembras de F. occidentalis. Esto permitiría la supervivencia de una mayor cantidad de células infectadas con el virus. La mayor incidencia de TSWV puede explicarse porque distintos cultivares inducen a los vectores comportamientos diferentes entre otras posibles causas

    Field programmable gate arrays for enhancing the speed and energy efficiency of quantum dynamics simulations

    No full text
    We present the first application of field programmable gate arrays (FPGAs) as new, customizable hardware architectures for carrying out fast and energy-efficient quantum dynamics simulations of large chemical/material systems. Instead of tailoring the software to fixed hardware, which is the typical case for writing quantum chemistry code for central processing units (CPUs) and graphics processing units (GPUs), FPGAs allow us to directly customize the underlying hardware (even at the level of specific electrical signals in the circuit) to give a truly optimized computational performance for quantum dynamics calculations. By offloading the most intensive and repetitive calculations onto an FPGA, we show that the computational performance of our real-time electron dynamics calculations can even exceed that of optimized commercial mathematical libraries running on high-performance GPUs. In addition to this impressive computational speedup, we show that FPGAs are immensely energy-efficient and consume 4 times less energy than modern GPU or CPU architectures. These energy savings are a practical and important metric for supercomputing centers (many of which exceed over $1 million in power costs alone), as exascale computing capabilities become more widespread and commonplace. Taken together, the implementation techniques and performance metrics of our study demonstrate that FPGAs could play a promising role in upcoming quantum chemistry and materials science applications, particularly for the acceleration and energy-efficient execution of quantum dynamics calculations.Fil: Rodríguez-Borbón, José M.. University Of California Riverside; Estados UnidosFil: Kalantar, Amin. University Of California Riverside; Estados UnidosFil: Yamijala, Sharma S. R. K. C.. University Of California Riverside; Estados UnidosFil: Oviedo, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Cs.químicas. Departamento de Química Teórica y Computacional; ArgentinaFil: Najjar, Walid. University Of California Riverside; Estados UnidosFil: Wong, Bryan M.. University Of California Riverside; Estados Unido

    ESTUDIO DEL IMPACTO TÉCNICO DE MEZCLAS DE CONCRETO HIDRÁULICO POR LA SUSTITUCIÓN PARCIAL DE CEMENTO POR ZEOLITA

    No full text
    La industria de la construcción cada vez más consciente de la necesidad de ejecutar obras con materiales que se obtengan y/o utilicen procesos industriales que minimicen la contaminación y, que contribuyan en el comportamiento de un producto como lo es el concreto hidráulico en la construcción, ha estado buscando alternativas de materiales que sustituyan total o parcialmente al cemento por otro cementante que contamine menos en su procesos de obtención y que conserve las propiedades o las mejore. Una alternativa para sustitución parcial del cemento es la zeolita, es un mineral que se obtiene por proceso de excavación y molienda de puzolana. La norma ASTM-618, define a las puzolanas como materiales silíceo o aluminio-silíceo que por sí solo poseen poco a ningún valor cementante, pero cuando se han dividido finamente y en presencia de agua e hidróxido de calcio (Cal) reaccionan químicamente a temperatura ambiente para formar cementantes (Miranda, 2008). Recientemente se ha estudiado el efecto de adicionar mineral Cal-Zeolita para la elaboración del concreto, cuyos resultados son favorables al comportamiento mecánico y su durabilidad (Dopico J.J., et al. 2009). Para la elaboración de morteros para recubrimientos al incorporar arenas zeolíticas como sustituto de la arena tradicional (Tiburcio et al. 2008). El presente proyecto evaluó el comportamiento del concreto hidráulico en estado fresco y endurecido al sustituir de manera parcial cemento por zeolita. Se enfocó a la evaluación del comportamiento mecánico como al diseño de la mezcla de concreto hidráulico fabricado con cemento normal y con cemento-zeolita. Tomando en cuenta los resultados obtenidos, la zeolita incorporada en porcentajes entre el 5% y 10 % tiende a valores de resistencias muy cercanos al concreto normal, los modelos obtenidos así lo corroboran, por lo que se puede concluir la factibilidad de sustitución parcial de cemento por zeolita tomando en cuenta el comportamiento mecánico

    An innovative multimodality approach for sentinel node mapping and biopsy in head and neck malignancies

    No full text
    Purpose: Recent innovations such as preoperative SPECT/CT, intraoperative imaging using portable devices and a hybrid tracer were evaluated in a multimodality approach for sentinel node (SN) mapping and biopsy in head and neck malignancies. Material and methods: The evaluation included 25 consecutive patients with head and neck malignancies (16 melanomas and 9 oral cavity squamous cell carcinomas). Patients were peritumorally injected with the hybrid tracer ICG-Tc-99m-nanocolloid. SNs were initially identified with lymphoscintigraphy followed by single photon emission computed tomography (SPECT/CT) 2 hours after tracer administration. During surgery a portable gamma camera in combination with a near-infrared fluorescence camera was used in addition to a handheld gamma ray detection probe to locate the SNs. Results: In all patients the use of conventional lymphoscintigraphy, SPECT/CT and the additional help of the portable gamma camera in one case were able to depict a total of 67 SNs (55 of them visualized on planar images, 11 additional on SPECT/CT and 1 additional with the portable gamma camera). A total of 67 of the preoperatively defined SNs together with 22 additional SNs were removed intraoperatively; 12 Out of the 22 additional SNs found during operation were located in the vicinity of the injection site in anatomical areas such as the periauricular or submental regions. The other 10 additional SNs were found by radioguided post-resection control of the excision SN site. Conclusion: In the present series 26% additional SNs were found using the multimodal approach, that incorporates SPECT/CT and intraoperative imaging to the conventional procedure. This approach appears to be useful in malignancies located close to the area of lymphatic drainage such as the periauricular area and the oral cavity. (C) 2013 Elsevier Espana, S.L.U. and SEMNIM. All rights reserve
    corecore