1,438 research outputs found

    X-ray view of four high-luminosity Swift/BAT AGN: Unveiling obscuration and reflection with Suzaku

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    The Swift/BAT nine-month survey observed 153 AGN, all with ultra-hard X-ray BAT fluxes in excess of 10^-11 erg cm^-2 s^-1 and an average redshift of 0.03. Among them, four of the most luminous BAT AGN (44.73 < Log L(BAT) < 45.31) were selected as targets of Suzaku follow-up observations: J2246.0+3941 (3C 452), J0407.4+0339 (3C 105), J0318.7+6828, and J0918.5+0425. The column density, scattered/reflected emission, the properties of the Fe K line, and a possible variability are fully analyzed. For the latter, the spectral properties from Chandra, XMM-Newton and Swift/XRT public observations were compared with the present Suzaku analysis. Of our sample, 3C 452 is the only certain Compton-thick AGN candidate because of i) the high absorption and strong Compton reflection; ii) the lack of variability; iii) the "buried" nature, i.e. the low scattering fraction (<0.5%) and the extremely low relative [OIII] luminosity. In contrast 3C 105 is not reflection-dominated, despite the comparable column density, X-ray luminosity and radio morphology, but shows a strong long-term variability in flux and scattering fraction, consistent with the soft emission being scattered from a distant region (e.g., the narrow emission line region). The sample presents high (>100) X-to-[OIII] luminosity ratios, confirming the [OIII] luminosity to be affected by residual extinction in presence of mild absorption, especially for "buried" AGN such as 3C 452. Three of our targets are powerful FRII radio galaxies, making them the most luminous and absorbed AGN of the BAT Seyfert survey despite the inversely proportional N_H - L_X relation.Comment: A&A paper in press, 17 page

    Methodological and terminological issues in animal-assisted interventions: An umbrella review of systematic reviews

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    Recently, animal-assisted interventions (AAIs), which are defined as psychological, educational, and rehabilitation support activities, have become widespread in different contexts. For many years, they have been a subject of interest in the international scientific community and are at the center of an important discussion regarding their effectiveness and the most appropriate practices for their realization. We carried out an umbrella review (UR) of systematic reviews (SRs), created for the purpose of exploring the literature and aimed at deepening the terminological and methodological aspects of AAIs. It is created by exploring the online databases PubMed, Google Scholar, and Cochrane Library. The SRs present in the high-impact indexed search engines Web of Sciences and Scopus are selected. After screening, we selected 15 SRs that met the inclusion criteria. All papers complained of the poor quality of AAIs; some considered articles containing interventions that did not always correspond to the terminology they have explored and whose operating practices were not always comparable. This stresses the need for the development and consequent diffusion of not only operational protocols, but also research protocols which provide for the homogeneous use of universally recognized terminologies, thus facilitating the study, deepening, and comparison between the numerous experiences described

    Sustainable landscape in arid zones : useful ornamental xeric species

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    Se analiza el valor económico, ecológico y paisajístico de especies vegetales, pertenecientes a la flora espontánea de Mendoza (Argentina), resistentes a la sequía y que pueden alcanzar porte arbóreo. Su empleo ahorra agua de riego en espacios verdes ornamentales y de protección ambiental. Se sugiere medidas de conservación de las especies espontáneas más útiles paisajísticamente, así como normas generales sobre métodos de plantación y mantenimiento. Se recomiendan especies leñosas espontáneas de la provincia, de bajo requerimiento hídrico, utilizables paisajísticamente.This paper analyzes the economic, ecological and landscape value of drought resistant species from the spontaneous flora of Mendoza (Argentina). Some of such species could reach tree size and its use might save the irrigation water used for ornamental and environmental protection areas. Actions to protect the most useful spontaneous species, as well as general rules for plantation and maintenance are suggested. Spontaneous wooden species of low water requirements, to use in different landscape objectives, are recommended.Fil: Codina, Ramón A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Manzano, Enrique R.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Carrieri, Sergio A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Fioretti, Sonia B.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción Agropecuari

    Photoassociation inside an optical dipole trap: absolute rate coefficients and Franck-Condon factors

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    We present quantitative measurements of the photoassociation of cesium molecules inside a far-detuned optical dipole trap. A model of the trap depletion dynamics is derived which allows to extract absolute photoassociation rate coefficients for the initial single-photon photoassociation step from measured trap-loss spectra. The sensitivity of this approach is demonstrated by measuring the Franck-Condon modulation of the weak photoassociation transitions into the low vibrational levels of the outer well of the 0g- state that correlates to the 6s+6p3/2 asymptote. The measurements are compared to theoretical predictions. In a magneto-optical trap these transitions have previously only been observed indirectly through ionization of ground state molecules

    Environmental value calculus of the frontal urban gardens. : Mendoza (Argentina)

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    Los espacios verdes y, en general, la vegetación que cumple funciones estéticas y de protección ambiental son valorados, medidos y calculados por el área destinada al cultivo, en lugar de basar los cálculos en los elementos vegetales constitutivos. Esto significa una simplificación excesiva de la valoración de la vegetación (actual o proyectada) que no aporta criterios de cuantificación valorativa necesarios, actualmente, tanto para preservar vegetación existente como para políticas de desarrollo urbano y proyectos de ingeniería del mejoramiento ambiental. En el presente trabajo se propone aplicar a la valoración de los jardines frontales urbanos de la ciudad de Mendoza una metodología cuantitativa desarrollada por R. Codina et al., que se apoya en un concepto nuevo que es su influencia como mejoradores ambientales. La ecuación de cálculo se integra con índices de valoración como el Índice de Vegetación Ambientalmente Activa y el Índice Ambiental Urbanístico, que permiten cuantificar la importancia urbanística y ambiental de la vegetación. También se propone una base para implementar una política de incentivo de los jardines frontales mediante la disminución del avalúo valor terreno del impuesto inmobiliario, en una escala progresiva según el Índice Ambiental Urbanístico de cada propiedad, tendiente a la transformación de la ciudad en una ciudad-jardín, mejorando la calidad de vida y el atractivo turístico urbano.The green spaces and in general, the vegetation used for aesthetics and environmental protection are valuated, measured and calculated through the area destinated to the cultivation instead of calculus based in the component vegetal elements. This means an excessive simplification in the vegetal valoration (current or projected) that not contribute with cuantitative valoration criterion, which are needed today in preservation of existent vegetation, urban development policies and in engineering projects of environmental improvement. This work proposes the application to the frontal urbans gardens in Mendoza city, of a cuantitative metodology developed by R. Codina et al., which is based in a new concept, it influences as environmental improvement. The calculus equation is to be composed of valoration indexes as the Environmental Active Vegetation Index and the Urbanistic Environmental Index, that allow the cuantification of the urbanistic and environmental importance of vegetation. Also is proposed a base for the implementation of an incentive policy of the frontals urban gardens through the diminution of the real estate tax land appraisal, in a progressive scale according the Urbanistic Environmental Index of each property, tending to transformation the city in a garden-city, to improve the life´s quality and the urban touristic charm.Fil: Codina, Ramón A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Passera, Carlos B.. Universidad Autónoma de Nuevo León (México). Facultad de Ciencias BiológicasFil: Naranjo, Gabriela. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Carrieri, Sergio A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Fioretti, Sonia B.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Manzano, Enrique R.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción Agropecuari

    Data model issues in the Cherenkov Telescope Array project

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    The planned Cherenkov Telescope Array (CTA), a future ground-based Very-High-Energy (VHE) gamma-ray observatory, will be the largest project of its kind. It aims to provide an order of magnitude increase in sensitivity compared to currently operating VHE experiments and open access to guest observers. These features, together with the thirty years lifetime planned for the installation, impose severe constraints on the data model currently being developed for the project. In this contribution we analyze the challenges faced by the CTA data model development and present the requirements imposed to face them. While the full data model is still not completed we show the organization of the work, status of the design, and an overview of the prototyping efforts carried out so far. We also show examples of specific aspects of the data model currently under development.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

    Formation of ultracold LiCs molecules

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    We present the first observation of ultracold LiCs molecules. The molecules are formed in a two-species magneto-optical trap and detected by two-photon ionization and time-of-flight mass spectrometry. The production rate coefficient is found to be in the range 10^{-18}\unit{cm^3s^{-1}} to 10^{-16}\unit{cm^3s^{-1}}, at least an order of magnitude smaller than for other heteronuclear diatomic molecules directly formed in a magneto-optical trap.Comment: 8 pages, 2 figure

    L\'evy flights of photons in hot atomic vapours

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    Properties of random and fluctuating systems are often studied through the use of Gaussian distributions. However, in a number of situations, rare events have drastic consequences, which can not be explained by Gaussian statistics. Considerable efforts have thus been devoted to the study of non Gaussian fluctuations such as L\'evy statistics, generalizing the standard description of random walks. Unfortunately only macroscopic signatures, obtained by averaging over many random steps, are usually observed in physical systems. We present experimental results investigating the elementary process of anomalous diffusion of photons in hot atomic vapours. We measure the step size distribution of the random walk and show that it follows a power law characteristic of L\'evy flights.Comment: This final version is identical to the one published in Nature Physic

    Molecular vibration in cold collision theory

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    Cold collisions of ground state oxygen molecules with Helium have been investigated in a wide range of cold collision energies (from 1 μ\muK up to 10 K) treating the oxygen molecule first as a rigid rotor and then introducing the vibrational degree of freedom. The comparison between the two models shows that at low energies the rigid rotor approximation is very accurate and able to describe all the dynamical features of the system. The comparison between the two models has also been extended to cases where the interaction potential He - O2_2 is made artificially stronger. In this case vibration can perturb rate constants, but fine-tuning the rigid rotor potential can alleviate the discrepancies between the two models.Comment: 11 pages, 3 figure

    Molecular Dynamics Simulation of Sympathetic Crystallization of Molecular Ions

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    It is shown that the translational degrees of freedom of a large variety of molecules, from light diatomic to heavy organic ones, can be cooled sympathetically and brought to rest (crystallized) in a linear Paul trap. The method relies on endowing the molecules with an appropriate positive charge, storage in a linear radiofrequency trap, and sympathetic cooling. Two well--known atomic coolant species, 9Be+{}^9{\hbox{Be}}^+ and 137Ba+{}^{137}{\hbox{Ba}}^+, are sufficient for cooling the molecular mass range from 2 to 20,000 amu. The large molecular charge required for simultaneous trapping of heavy molecules and of the coolant ions can easily be produced using electrospray ionization. Crystallized molecular ions offer vast opportunities for novel studies.Comment: Accepted for publication in Phys. Rev.
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