674 research outputs found

    Sintomatologia, etiología y algunos factores que inciden en la caída de plántulas de algodonero en Andalucía Occidental

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    Se describen los resultados de dos prospecciones sobre Caída de plántulas de algodonero efectuadas en 1999 en 28 parcelas con historia de incidencia de la enfermedad en Andalucía occidental. En la prospección temprana se recogieron 401 plantas de rodales con problemas y se encontró una mayor incidencia de Rhizoctonia solani. En la tardía se recogieron 976 plantas al azar y Thielaviopsis basteóla fue el que se encontró con más frecuencia, notándose un incremento de la importancia de este hongo en los suelos arcillosos al sur de Sevilla. Se ha estudiado la sintomatologia presente y encontrado una asociación entre los aislamientos de R. solani y la muerte de las plántulas y entre T. basicola y las necrosis más oscuras y negras, comprobándose además que un elevado número de síndromes estuvieron causados por agentes abióticos. Se presentan datos previos de las relaciones entre la frecuencia de aislamientos de estos patógenos y algunas prácticas culturales como fueron el quemado de los restos del cultivo anterior y las dosis del abonado de fondo. En este trabajo se realizaron análisis de la germinación de la semilla sembrada por los agricultores y se hacen consideraciones sobre el "vigor" de la semilla empleadaResults of two cotton surveys on cotton damping-off realized in west Andalucía (Spain) are described. Twenty eight cotton fields known as disease prone were sampled. At first survey 401 plants were collected from infected areas of the fields and Rhizoctonia solani was the fungus most frequently recovered. One month later, the same fields were randomly sampled and 976 plants were collected founding a higher incidence of Thielaviopsis basicola, specially on clay soils southern Seville. Plants were classified by symptoms and related to isolated fungi. R. solani was associated with seedling death and T. basicola with dark brown or black necrosis. A high percentage of syndromes had an abiotic origin. Preliminary conclusions on relationships between both fungi and fertilization management and previous crops stubble are presented. Germination of seeds planted by farmers was studied and some considerations about their vigor are made

    Métodos de trabajo y resultados de refuerzos en madera de un forjado del siglo XVII de la Sacristía de San Miguel en Morón de la Frontera (Sevilla)

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    During the 20th century numerous solutions for reinforcing wood sub-floors with concrete slabs and frameworks were introduced with the aim of remedying malfunctions due to rheological reasons or the deterioration of some of the components. In certain cases, however, these solutions created an excessive load, and as time went by they aggravated the original pathologies, to the extent where props were required. This is precisely the case of one of the sub-floors in the sacristy that was abutted to the parish church of San Miguel in Morón during the 17th century. The sub-floors on both levels are made of timber beams and hollow plaster bricks. As part of the restoration works carried out in 2013, a concrete slab added for reinforcement in 1970 was removed and replaced with a new reinforcement made out of plywood, pre-tensioning the joints between the new and old pieces. This has significantly reduced the cambers, preserved all the principal elements and led to a more efficient performance. This paper describes the conditions prior to the intervention, the process followed and the results obtained during these restoration works. It also assesses the calculations and projections made.Durante el pasado siglo se pusieron en práctica numerosas soluciones de refuerzo de antiguos forjados de madera mediante losas que pretendían suplir las carencias de funcionamiento por causas reológicas o por deterioro de algunas de sus piezas. Algunas de estas soluciones, sin embargo, supusieron una sobrecarga innecesaria que agravó las patologías previas con el paso del tiempo, hasta el punto de requerir su apuntalamiento. Éste es el caso de uno de los forjados de la sacristía de la parroquia de San Miguel de Morón, un edificio levantado en el transcurso del siglo XVII anexo al templo. Los pisos de sus dos plantas estaban solucionados mediante forjados de vigas de madera y bovedillas de yeso. Como parte de los trabajos de restauración realizados en 2013, se desmontó un refuerzo previo realizado en 1970 mediante losa de hormigón, para ejecutar posteriormente un novedoso tipo de refuerzo con madera laminada, pretensando la unión entre las piezas nuevas y viejas, lo que ha permitido reducir de forma notable las flechas, mantener todos sus elementos principales y obtener un comportamiento más eficiente. La presente aportación expone las condiciones previas a la intervención, el proceso seguido y los resultados obtenidos durante esta restauración valorando los cálculos y previsiones realizadas

    The Minimum-Uncertainty Squeezed States for for Atoms and Photons in a Cavity

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    We describe a six-parameter family of the minimum-uncertainty squeezed states for the harmonic oscillator in nonrelativistic quantum mechanics. They are derived by the action of corresponding maximal kinematical invariance group on the standard ground state solution. We show that the product of the variances attains the required minimum value 1/4 only at the instances that one variance is a minimum and the other is a maximum, when the squeezing of one of the variances occurs. The generalized coherent states are explicitly constructed and their Wigner function is studied. The overlap coefficients between the squeezed, or generalized harmonic, and the Fock states are explicitly evaluated in terms of hypergeometric functions. The corresponding photons statistics are discussed and some applications to quantum optics, cavity quantum electrodynamics, and superfocusing in channeling scattering are mentioned. Explicit solutions of the Heisenberg equations for radiation field operators with squeezing are found.Comment: 27 pages, no figures, 174 references J. Phys. B: At. Mol. Opt. Phys., Special Issue celebrating the 20th anniversary of quantum state engineering (R. Blatt, A. Lvovsky, and G. Milburn, Guest Editors), May 201

    Autophagy upregulation and loss of NF-kB in oxidative stress-related immunodeficient SAMP8 mice

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    Aged spleens from senescence-accelerated prone mice 8 (SAMP8) and senescence-accelerated resistant mice 1 (SAMR1) were examined to determine whether sex or melatonin had an effect on oxidative stress-related immune impairments. We observed that the immunosenescence of SAMP8 mice was associated with a redox imbalance, leading to an age-related increase in oxidative damage, resulting from a decrease in antioxidant defense and protease activity. Moreover, increased apoptotic cell death, a decrease in proliferative activity and the loss of NF-kB activation were also related to the immunodeficiency seen in SAMP8 compared to SAMR1 mice. Females demonstrated higher oxidative stress-related alterations in the immune response, and subsequent, melatonin treatment provided the best protective effects. Pathways involved in autophagy were upregulated in SAMP8 as an adaptive response to oxidative stress, in an attempt to rescue the cell from increased apoptosis and age-related immunodeficiency. However, the NF-kB signaling and autophagic processes were unaffected by treatment with melatonin. Therefore, we propose a key role for NF-kB signaling and autophagy in the oxidative stress-related immunosenescent spleens of SAMP8 mice

    Transition metal oxide nanocatalysts for the deoxygenation of palm oil to green diesel

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    This study investigated the hydrodeoxygenation of palm oil by different oxide nanocatalysts of transition metals α -Fe2O3, NiO, and NiFe2O4, which were synthesized by hot injection. All nanomaterials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and dynamic light dispersion. The catalytic evaluation was performed in a Parr-type reactor at 350°C, 3.5 MPa of H2 pressure, and 3 h of reaction. The liquid product obtained was analyzed by ultraviolet-visible light spectroscopy to identify the n-C16 generated during the reaction. The activity in the deoxygenation of fatty acids to produce n-C16 hydrocarbons has the following order: α-Fe2O3 < NiFe2O4 < NiO

    Induction of androgenesis and production of haploid embryos in anther cultures of borage (Borago officinalis L.)

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    [EN] Borage (Borago officinalis L.) is an important medicinal plant with different culinary, pharmaceutical and industrial properties. Unfortunately, there are no published reports on the establishment of protocols to produce DHs in this species up to now. In this work, we show for the first time the induction of borage microspores to become embryogenic calli, from which haploid embryos are produced. In addition, we evaluated the effect of using different flower bud sizes, carbon sources, concentrations of 2,4-D and BAP, cold (4 A degrees C) pretreatments and heat shock treatments. Production of total calli, embryogenic calli and callus-derived embryos was differently affected by the different parameters studied. Our results showed that the use of 5-7 mm-long flower buds, a cold (4 A degrees C) pretreatment during 4 days, a 32 A degrees C heat shock for 3 days, and the addition of 3 % maltose and 2 mgl(-1) 2,4-D and 1 mgl(-1) BAP to the culture medium, was beneficial for embryo production. Overall, this work demonstrates that DH technology is possible in borage, and opens the door for future improvements needed to finally obtain borage DH plants.Eshaghi, ZC.; Abdollahi, MR.; Moosavi, SS.; Deljou, A.; Seguí-Simarro, JM. (2015). Induction of androgenesis and production of haploid embryos in anther cultures of borage (Borago officinalis L.). Plant Cell, Tissue and Organ Culture. 122:321-329. doi:10.1007/s11240-015-0768-5S321329122Abdollahi MR, Moieni A, Javaran MJ (2004) Interactive effects of shock and culture density on embryo induction in isolated microspore culture of Brassica napus L. cv. 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    High Mitochondrial DNA Stability in B-Cell Chronic Lymphocytic Leukemia

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    BACKGROUND: Chronic Lymphocytic Leukemia (CLL) leads to progressive accumulation of lymphocytes in the blood, bone marrow, and lymphatic tissues. Previous findings have suggested that the mtDNA could play an important role in CLL. METHODOLOGY/PRINCIPAL FINDINGS: The mitochondrial DNA (mtDNA) control-region was analyzed in lymphocyte cell DNA extracts and compared with their granulocyte counterpart extract of 146 patients suffering from B-Cell CLL; B-CLL (all recruited from the Basque country). Major efforts were undertaken to rule out methodological artefacts that would render a high false positive rate for mtDNA instabilities and thus lead to erroneous interpretation of sequence instabilities. Only twenty instabilities were finally confirmed, most of them affecting the homopolymeric stretch located in the second hypervariable segment (HVS-II) around position 310, which is well known to constitute an extreme mutational hotspot of length polymorphism, as these mutations are frequently observed in the general human population. A critical revision of the findings in previous studies indicates a lack of proper methodological standards, which eventually led to an overinterpretation of the role of the mtDNA in CLL tumorigenesis. CONCLUSIONS/SIGNIFICANCE: Our results suggest that mtDNA instability is not the primary causal factor in B-CLL. A secondary role of mtDNA mutations cannot be fully ruled out under the hypothesis that the progressive accumulation of mtDNA instabilities could finally contribute to the tumoral process. Recommendations are given that would help to minimize erroneous interpretation of sequencing results in mtDNA studies in tumorigenesis
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