799 research outputs found

    Harmonic states for the free particle

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    Different families of states, which are solutions of the time-dependent free Schr\"odinger equation, are imported from the harmonic oscillator using the Quantum Arnold Transformation introduced in a previous paper. Among them, infinite series of states are given that are normalizable, expand the whole space of solutions, are spatially multi-localized and are eigenstates of a suitably defined number operator. Associated with these states new sets of coherent and squeezed states for the free particle are defined representing traveling, squeezed, multi-localized wave packets. These states are also constructed in higher dimensions, leading to the quantum mechanical version of the Hermite-Gauss and Laguerre-Gauss states of paraxial wave optics. Some applications of these new families of states and procedures to experimentally realize and manipulate them are outlined.Comment: 21 pages, 3 figures. Title changed, content added, references adde

    The common envelope origins of the fast jet in the planetary nebula M 3-38

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    We present the analysis of Multi-Espectr\'ografo en GTC de Alta Resoluci\'on para Astronom\'ia (MEGARA) high-dispersion integral field spectroscopic observations of the bipolar planetary nebula (PN) M 3-38. These observations unveil the presence of a fast outflow aligned with the symmetry axis of M 3-38 that expands with a velocity up to ±\pm225 km s1^{-1}. The deprojected space velocity of this feature can be estimated to be \approx32060+130^{+130}_{-60} km s1^{-1}, which together with its highly collimated morphology suggests that it is one of the fastest jet detected in a PN. We have also used Kepler observations of the central star of M 3-38 to unveil variability associated with a dominant period of 17.7 days. We attribute this to the presence of a low-mass star with an orbital separation of \approx0.12-0.16 au. The fast and collimated ejection and the close binary system point towards a common envelope formation scenario for M 3-38.Comment: 9 pages, 5 figures, Accepted ApJ Lette

    Effect of wild ungulate density on invertebrates in a Mediterranean ecosystem

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    Efecto de la densidad de ungulados silvestres sobre los invertebrados en un ecosistema Mediterráneo En las últimas décadas, la abundancia y distribución de determinadas especies de caza mayor, especialmente el ciervo rojo (Cervus elaphus) y el jabalí (Sus scrofa), han aumentado en la zona centromeridional de España como resultado de las estrategias de gestión cinegética. La alta densidad de estas especies de ungulados puede afectar a la abundancia de los invertebrados epigeos. Estudiamos la relación entre la abundancia de las especies de caza mayor y la biodiversidad, la riqueza de taxones, la biomasa de invertebrados y su frecuencia en nueve fincas de caza, y se comparó con las zonas de exclusión de ungulados. De por sí, la exclusión de ungulados afectó a la riqueza de invertebrados, ya que se encontraron valores más bajos en las parcelas abiertas, mientras que las mayores diferencias en la diversidad de invertebrados entre parcelas abiertas y cercadas se encontraron en zonas con una alta densidad de jabalíes. Donde la densidad de jabalíes era alta, el número de invertebrados disminuyó, mientras que donde era baja, el ciervo rojo tuvo un efecto positivo en la abundancia de invertebrados. Así, las parcelas cercadas parecían ofrecer refugio a los invertebrados, sobre todo donde los jabalíes eran abundantes. Este estudio apoya la idea de que las poblaciones con una alta densidad de ungulados perjudican a la estructura de las comunidades faunísticas, probablemente debido a la disminución de la disponibilidad de alimentos como consecuencia del sobrepastoreo, la modificación de las condiciones de los micronichos ecológicos y la depredación directa. Sin embargo, los efectos dependieron del grupo de invertebrados, ya que las especies saprofitas podrían beneficiarse de la alta abundancia de ungulados. Nuestros resultados reflejan la necesidad de controlar la densidad de las poblaciones de ungulados en condiciones mediterráneas en el suroeste de Europa y de establecer parcelas de exclusión de ungulados.In recent decades, the abundance and distribution of certain big game species, particularly red deer (Cervus elaphus) and wild boar (Sus scrofa), have increased in south central Spain as a result of hunting management strategies. The high density of these ungulate species may affect the abundance of epigeous invertebrates. We tested the relationships between big game abundance and biodiversity, taxon richness, the biomass of invertebrates and their frequency on nine hunting estates and in comparison to ungulate exclusion areas. Ungulate exclusion itself affected invertebrate richness, since lower values were found in the open plots, whereas the highest differences in invertebrate diversity between fenced and open plots was found in areas with high wild boar density. Where wild boar densities were high, the number of invertebrates decreased, while where they were low, red deer had a positive effect on invertebrate abundance. Fenced plots thus seemed to provide refuge for invertebrates, particularly where wild boar were abundant. This study supports the idea that the structure of fauna communities is damaged by high density populations of ungulates, probably due to decreased food availability owing to overgrazing, modified conditions of ecological microniches and direct predation. However, the effects depended on the group of invertebrates, since saprophytic species could benefit from high ungulate abundance. Our findings reflect the need to control ungulate population density under Mediterranean conditions in south–western Europe and to implement ungulate exclusion plots.Efecto de la densidad de ungulados silvestres sobre los invertebrados en un ecosistema Mediterráneo En las últimas décadas, la abundancia y distribución de determinadas especies de caza mayor, especialmente el ciervo rojo (Cervus elaphus) y el jabalí (Sus scrofa), han aumentado en la zona centromeridional de España como resultado de las estrategias de gestión cinegética. La alta densidad de estas especies de ungulados puede afectar a la abundancia de los invertebrados epigeos. Estudiamos la relación entre la abundancia de las especies de caza mayor y la biodiversidad, la riqueza de taxones, la biomasa de invertebrados y su frecuencia en nueve fincas de caza, y se comparó con las zonas de exclusión de ungulados. De por sí, la exclusión de ungulados afectó a la riqueza de invertebrados, ya que se encontraron valores más bajos en las parcelas abiertas, mientras que las mayores diferencias en la diversidad de invertebrados entre parcelas abiertas y cercadas se encontraron en zonas con una alta densidad de jabalíes. Donde la densidad de jabalíes era alta, el número de invertebrados disminuyó, mientras que donde era baja, el ciervo rojo tuvo un efecto positivo en la abundancia de invertebrados. Así, las parcelas cercadas parecían ofrecer refugio a los invertebrados, sobre todo donde los jabalíes eran abundantes. Este estudio apoya la idea de que las poblaciones con una alta densidad de ungulados perjudican a la estructura de las comunidades faunísticas, probablemente debido a la disminución de la disponibilidad de alimentos como consecuencia del sobrepastoreo, la modificación de las condiciones de los micronichos ecológicos y la depredación directa. Sin embargo, los efectos dependieron del grupo de invertebrados, ya que las especies saprofitas podrían beneficiarse de la alta abundancia de ungulados. Nuestros resultados reflejan la necesidad de controlar la densidad de las poblaciones de ungulados en condiciones mediterráneas en el suroeste de Europa y de establecer parcelas de exclusión de ungulados

    Comportamiento de 13 modelos de cinta de riego en condiciones de invernadero con agua regenerada

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    El objetivo de este trabajo ha sido seleccionar modelos de cinta de riego con una mejor adaptación a las condiciones de invernadero y riego con aguas regeneradas. Se ha evaluado el comportamiento de 13 modelos comerciales de cintas de riego seleccionados de entre los más utilizados en los cultivos hortícolas al aire libre, y aquellos que, las empresas instaladoras y fabricantes consideren que, por sus características, pueden tener un buen comportamiento con este tipo de aguas. En la evaluación de campo todos los emisores han presentado valores de uniformidad elevados al comienzo de la campaña de riego. Cinco de las cintas se clasifican como excelentes y el resto como buenas. Al finalizar las 114 horas de trabajo decae sustancialmente la uniformidad. El comportamiento tras la finalización de la primera campaña de riego se puede considerar equiparable al obtenido en un estudio previo con una selección de 20 emisores en ramal convencional y este tipo de aguas. Se puede concluir que las cintas de riego localizado pueden ser una alternativa a los ramales de riego convencionales cuando se riega con aguas residuales urbanas regeneradas, siempre que se elija un material de una mínima calidad y el ratio de sustitución garantice una uniformidad alta

    Acute stress assessment using infrared thermography in fattening rabbits reacting to handling under winter and summer conditions

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    Aim of study: This study assesses acute stress by measuring, through infrared thermography in summer and winter, the temperature of the eye, outer ear, inner ear and nose in 40 fattening rabbits before and after handling.Area of study: Seville (Spain).Material and methods: Body thermographic temperatures were recorded during a 38-day fattening period twice weekly and twice a day, before and after the handler held the rabbits in their arms for one minute. Ambient temperature and relative humidity were also recorded, and their influence on body temperatures was assessed. For each anatomical part, the variation of the temperature between the handled and undisturbed rabbit, and the differential temperature between the anatomical part in the undisturbed rabbit and the ambient temperature were calculated.Main results: The variation in temperatures between handled and undisturbed rabbits ranged from 0.25±0.041 ºC for eye to 3.09±0.221 ºC for outer ear in summer and -0.41±0.182 ºC for nose to 2.09±0.178 ºC for outer ear in winter. The day of the fattening period influenced all the temperature traits during summer and winter, except for the inner ear in winter. In summer, unlike winter, the temperature variation at the end of fattening period between handled and undisturbed rabbits was lower than at weaning (-0.04 to 1.94 ºC vs. 0.54 to 5.52 ºC, respectively). The temperatures in undisturbed rabbits were correlated with ambient temperature.Research highlights: Measuring body temperature with infrared thermography is a useful tool to evaluate acute stress in handled rabbits, with the inner ear and eye the most reliable body parts for measuring it

    Active surveillance in prostate cancer: role of available biomarkers in daily practice

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    Prostate cancer (PCa) is the most commonly diagnosed cancer in men. The diagnosis is currently based on PSA levels, which are associated with overdiagnosis and overtreatment. Moreover, most PCas are localized tumours; hence, many patients with low-/very low-risk PCa could benefit from active surveillance (AS) programs instead of more aggressive, active treatments. Heterogeneity within inclusion criteria and follow-up strategies are the main controversial issues that AS presently faces. Many biomarkers are currently under investigation in this setting; however, none has yet demonstrated enough diagnostic ability as an independent predictor of pathological or clinical progression. This work aims to review the currently available literature on tissue, blood and urine biomarkers validated in clinical practice for the management of AS patients

    VP2 potentiates the proteccion induced by VP6 against the rotavirus infection in a DNA vaccine model

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    Viruses like particles (VLPs) composed of VP2/VP6 are very effective in inducing protection against the rotavirus infection in animal models. Individually, VP6 also can induce protection against the infection; however, there is no information about the immunogenicity of VP2. The aim of this work was to evaluate the efficacy of DNA vaccines that codify for VP2 and VP6 alone or combined to induce protection against the rotavirus infection. Murine rotavirus VP2 and VP6 genes were cloned into the pCDNA-3 vector. Adult BALB/c mice were inoculated 3 times by intramuscular injections with 100 or 200 mg of pCDNA-3VP2 and pCDNA-3VP6, alone or combined. Two weeks after the last inoculation, mice were challenged with the murine rotavirus EDIM. We found that both plasmids pCDNA-3VP2 and pCDNA-3VP6 were able to induce rotavirus-specific serum antibodies, but not intestinal rotavirus-specific IgA. Only pCDNA-3VP6 at 200 mg could induce 30 % protection against the infection. Co-administration of 100 mg of pCDNA-3VP2 with 100 mg of pCDNA-3VP6 induced 35 % protection. When different ratios of pCDNA-3VP2/pCDNA-3VP6 were used, it was found that the co-administration of 10 µg pCDNA-3VP2/ 100 µg pCDNA-3VP6 gave the best result with up to 55 % protection. These results indicate that the DNA plasmid expressing VP6 is a better vaccine candidate that the one expressing VP2 but co-administration of both plasmids is a good alternative to potentiate the protection induced by VP6, probably by the formation of VLPs VP2/VP6 in vivo

    Experimental and theoretical assessment of native oxide in the superconducting TaN

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    In this manuscript, we show through an experimental-computational proof of concept the native oxide formation into superconducting TaN films. First, TaN was synthesized at an ultra-high vacuum system by reactive pulsed laser deposition and characterized in situ by X-ray photoelectron spectroscopy. The material was also characterized ex situ by X-ray diffraction, transmission electron microscopy, and the four-point probe method. It was detected that TaN contained considerable oxygen impurities (up to 26 %O) even though it was grown in an ultra-high vacuum chamber. Furthermore, the impurified TaN evidence a face-centered cubic crystalline structure only and exhibits superconductivity at 2.99 K. To understand the feasibility of the native oxide in TaN, we study the effect of incorporating different amounts of O atoms in TaN using ab-initio calculations. A thermodynamic stability analysis shows that a TaOxN1-x model increases its stability as oxygen is added, demonstrating that oxygen may always be present in TaN, even when obtained at ultra-high vacuum conditions. All analyzed models exhibit metallic behavior. Charge density difference maps reveal that N and O atoms have a higher charge density redistribution than Ta atoms. The electron localization function maps and line profiles indicate that Ta-O and Ta-N bonds are mainly ionic. As expected, stronger ionic behavior is observed in the Ta-O bonds due to the electronegativity difference between O and N atoms. Recent evidence points to superconductivity in bulk TaO, confirming the asseverations of superconductivity in our samples. The results discussed here highlight the importance of considering native oxide when reporting superconductivity in TaN films since the TaO regions formed in the compound may be key to understanding the different critical temperatures reported in the literature.Comment: 23 pages, 7 figure

    IAA : Información y actualidad astronómica (27)

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    Sumario : Sagitario A*: el agujero negro en el corazón de la Vía Láctea.-- ESPECIAL: Año Internacional de la Astronomía.-- HISTORIAS DE ASTRONOMÍA. Chandrasekhar y los agujeros negros.-- DECONSTRUCCIÓN Y otros ENSAYOS. Binarias de rayos X.-- EL “MOBY DICK” DE...Pedro Amado.-- ACTUALIDAD.-- ENTRE BASTIDORES.-- CIENCIA: PILARES E INCERTIDUMBRES. El tiempo.-- ACTIVIDADES IAA.N
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