2,156 research outputs found

    Algebraic computation of some intersection D-modules

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    Let XX be a complex analytic manifold, DXD\subset X a locally quasi-homogeneous free divisor, EE an integrable logarithmic connection with respect to DD and LL the local system of the horizontal sections of EE on XDX-D. In this paper we give an algebraic description in terms of EE of the regular holonomic D-module whose de Rham complex is the intersection complex associated with LL. As an application, we perform some effective computations in the case of quasi-homogeneous plane curves.Comment: 18 page

    Deformation Quantization: Quantum Mechanics Lives and Works in Phase-Space

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    Wigner's quasi-probability distribution function in phase-space is a special (Weyl) representation of the density matrix. It has been useful in describing quantum transport in quantum optics; nuclear physics; decoherence (eg, quantum computing); quantum chaos; "Welcher Weg" discussions; semiclassical limits. It is also of importance in signal processing. Nevertheless, a remarkable aspect of its internal logic, pioneered by Moyal, has only emerged in the last quarter-century: It furnishes a third, alternative, formulation of Quantum Mechanics, independent of the conventional Hilbert Space, or Path Integral formulations. In this logically complete and self-standing formulation, one need not choose sides--coordinate or momentum space. It works in full phase-space, accommodating the uncertainty principle. This is an introductory overview of the formulation with simple illustrations.Comment: LaTeX, 22 pages, 2 figure

    Dynamical description of the buildup process in resonant tunneling: Evidence of exponential and non-exponential contributions

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    The buildup process of the probability density inside the quantum well of a double-barrier resonant structure is studied by considering the analytic solution of the time dependent Schr\"{o}dinger equation with the initial condition of a cutoff plane wave. For one level systems at resonance condition we show that the buildup of the probability density obeys a simple charging up law, Ψ(τ)/ϕ=1eτ/τ0,| \Psi (\tau) / \phi | =1-e^{-\tau /\tau_0}, where ϕ\phi is the stationary wave function and the transient time constant τ0\tau_0 is exactly two lifetimes. We illustrate that the above formula holds both for symmetrical and asymmetrical potential profiles with typical parameters, and even for incidence at different resonance energies. Theoretical evidence of a crossover to non-exponential buildup is also discussed.Comment: 4 pages, 2 figure

    Colaboración en la dirección estratégica: ¿Cómo la gerencia moderna logra el éxito organizacional?

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    1 archivo PDF (10 páginas). magyeaddRESUMEN: Los retos y costos de las actividades en un mundo global han ido incrementándose día tras día, por ello, las organizaciones se orientan al establecimiento de relaciones comerciales diferentes a las formas tradicionales basadas en la adquisición de bienes y servicios en el mercado. Esta situación toma fuerza a partir de la década de los ochenta, cuando los entornos organizacionales se volvieron cada vez más complejos e inciertos. En esos momentos las organizaciones se vieron obligadas a obtener materias primas, habilidades, innovación, financiamiento o acceso a mercados mediante estrategias que les permitieran seguir creciendo, estrategias basadas principalmente en la colaboración con otras organizaciones. Esta situación requiere que las organizaciones compartan recursos y actividades para poder alcanzar sus objetivos particulares. Varias son las formas de colaboración organizacional, entre las que se pueden mencionar las alianzas estratégicas, las aventuras conjuntas, y las redes organizacionales (networks). Estás últimas consisten en acuerdos mediante las cuales dos o más organizaciones buscan obtener resultados que de manera individual no pudieran lograr, relación basada en la confianza, comunicación y el compromiso mutuo. En general, en este artículo se analiza la importancia actual de la dirección estratégica, así como la necesidad que tienen las organizaciones de colaborar para poder sobrevivir en un mundo complejo, global y cada día más demandante. ABSTRACT: The challenges and costs of activities in a global world have been increasing day by day, therefore, organizations are geared to the establishment of different trade relations to traditional forms based on the acquisition of goods and services in the market. This situation takes strength from the eighties, when the organizational environment became increasingly complex and uncertain. At that time the organizations were forced to obtain raw materials, skills, innovation, financing or market access through strategies that enable them to continue to grow, mainly based strategies in collaboration with other organizations. This situation requires organizations to share resources and activities to achieve their particular goals. There are several forms of organizational collaboration, among which may be mentioned strategic alliances, joint adventures, and organizational networks (networks). You are latter consist of agreements whereby two or more organizations seek to obtain results that individually could not achieve, relationship based on trust, communication and mutual commitment. In general, in this article the current importance of strategic direction as well as the need for organizations to collaborate to survive in a complex world, global and more demanding every day is analyzed. PALABRAS CLAVE: Organizaciones, globalización. KEYWORDS: Organizations, globalizatio

    Necesidades en salud oral de personas que viven con VIH/SIDA en Chile

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    Tesis (Cirujano Dentista)Objetivos: Determinar las necesidades en salud oral de personas que viven con VIH/SIDA en Chile. Materiales y métodos: Estudio cualitativo exploratorio. Se determinó cuáles son las necesidades en salud de personas que viven con VIH/SIDA mediante 2 focus group en los meses de junio y julio del 2017, con un total de 13 participantes, todos hombres entre 18 y 70 años diagnosticados con VIH positivo, pertenecientes a la Fundación Diversa. Resultados: Los resultados obtenidos se relacionan con los objetivos planteados en este estudio; Necesidad de información sobre temáticas de salud oral, Necesidad de tratamientos odontológicos y Medios de entrega de información en salud oral. Conclusión: En base a los resultados obtenidos, podemos concluir que hay una evidente necesidad de información sobre salud oral, necesidad de tratamiento odontológico integral y necesidad frente a medios de entrega de información certificados, de fácil acceso y comprensión por parte de las personas que viven con VIH/SIDA. Siendo esto de relevancia en la salud pública, ya que actualmente la población que vive con esta condición se ha incrementado en nuestro país y sus necesidades en salud oral no han sido determinadas, limitándolos a recibir una atención de salud integral y multidisciplinaria.Objectives: To determine the oral health needs of people living with HIV / AIDS in Chile. Materials and methods: Qualitative exploratory study. We determined the health needs of people living with HIV / AIDS through 2 focus groups in the months of June and July 2017, with a total of 13 participants, all men between 18 and 70 years diagnosed with HIV positive, belonging to the Diversa Foundation. Results: The results obtained relate to the objectives proposed in this study; Need for information on oral health issues, need for dental treatments and means of delivery of information in oral health. Conclusion: Based on the results obtained, we can conclude that there is a clear need for information on oral health, the need for comprehensive dental treatment and the need for certified means for delivery of information, easily accessible and understood by the people who live with HIV / AIDS. This being of relevance in public health, since currently the population living with this condition has increased in our country and their oral health needs have not been determined, limiting them to receive comprehensive and multidisciplinary health car

    Mid-Infrared Variability of protostars in IC 1396A

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    We have used Spitzer/IRAC to conduct a photometric monitoring program of the IC1396A dark globule in order to study the mid-IR (3.6 - 8 micron) variability of the heavily embedded Young Stellar Objects (YSOs) present in that area. We obtained light curves covering a 14 day timespan with a twice daily cadence for 69 YSOs, and continuous light curves with approximately 12 second cadence over 7 hours for 38 YSOs. Typical accuracies for our relative photometry were 1-2% for the long timespan data and a few mmag, corresponding to less than 0.5%, for the 7 hour continuous "staring-mode" data. More than half of the YSOs showed detectable variability, with amplitudes from ~0.05 mag to ~0.2 mag. About thirty percent of the YSOs showed quasi-sinusoidal light curve shapes with apparent periods from 5-12 days and light curve amplitudes approximately independent of wavelength over the IRAC bandpasses. We have constructed models which simulate the time dependent spectral energy distributions of Class I and I I YSOs in order to attempt to explain these light curves. Based on these models, the apparently periodic light curves are best explained by YSO models where one or two high latitude photospheric spots heat the inner wall of the circumstellar disk, and where we view the disk at fairly large inclination angle. Disk inhomogeneities, such as increasing the height where the accretion funnel flows to the stellar hotspot, enhances the light curve modulations. The other YSOs in our sample show a range of light curve shapes, some of which are probably due to varying accretion rate or disk shadowing events. One star, IC1396A-47, shows a 3.5 hour periodic light curve; this object may be a PMS Delta Scuti star

    Decay process accelerated by tunneling in its very early stage

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    We examine a fast decay process that arises in the transition period between the Gaussian and exponential decay processes in quantum decay systems. It is usually expected that the decay is decelerated by a confinement potential barrier. However, we find a case where the decay in the transition period is accelerated by tunneling through a confinement potential barrier. We show that the acceleration gives rise to an appreciable effect on the time evolution of the nonescape probability of the decay system.Comment: 4 pages, 6 figures; accepted for publication in Phys. Rev.

    Greening plans as (re)presentation of the city : toward an inclusive and gender-sensitive approach to urban greenspaces

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    Altres ajuts: acords transformatius de la UABUnidad de excelencia María de Maeztu CEX2019-000940-MCities around the world are increasingly expanding their sustainability agendas and adopting urban green and blue infrastructure planning as a strategy to become more resilient, healthy and sustainable. However, the development of urban greening governance often lacks a holistic vision that considers social inequities within the planning, implementation and management of green and blue spaces. Further, gender inequities have been a specific dimension particularly overlooked in urban greening planning, despite gender concerns gaining increasing political relevance in recent years. In this research, we assessed the extento to which social and gender equity are being considered in urban greening plans and projects at the local level. We chose Barcelona (Spain) as main case study due to its pioneering role in implementing crosscutting equity and gender policies at the municipal level. Building on document analysis and semi-structured interviews with key stakeholders, we examined how social justice and gender are understood and operationalized in practice, from the design phase to implementation and maintenance of greening projects. Our findings suggest a shift in the role of urban greening which evolved from an ornamental role to a multifunctional vision of greening and is recently incorporating equity and inclusivity concerns. We identified three action areas of inclusive, gender-sensitive urban green planning practices: first, the incorporation of inclusivity and care as guiding visible values to recognize multiple needs of city residents; second, urban design for different uses and perceptions of greenspaces, particularly in relation to accessibility and autonomy; and third, the awareness and expertise from municipal staff vis-à-vis the consideration of social and gender equity in green planning and participatory approaches. Finally, we provide practical examples of the strategies that the City of Barcelona is implementing in each area and discuss some challenges and limitations, including what we identify as ad hoc intersectional greening
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