Holographic Relaxation of Finite Size Isolated Quantum Systems

We study holographically the out of equilibrium dynamics of a finite size closed quantum system in 2+1 dimensions, modelled by the collapse of a shell of a massless scalar field in AdS4. In global coordinates there exists a variety of evolutions towards final black hole formation which we relate with different patterns of relaxation in the dual field theory. For large scalar initial data rapid thermalization is achieved as a priori expected. Interesting phenomena appear for small enough amplitudes. Such shells do not generate a black hole by direct collapse, but quite generically an apparent horizon emerges after enough bounces off the AdS boundary. We relate this bulk evolution with relaxation processes at strong coupling which delay in reaching an ergodic stage. Besides the dynamics of bulk fields, we monitor the entanglement entropy, finding that it oscillates quasi-periodically before final equilibration. The radial position of the traveling shell is brought into correspondence with the evolution of the entanglement pattern in the dual field theory. The entanglement entropy is not only able to portrait the streaming of entangled excitations, but it is also a useful probe of interaction effects.Comment: 37 pages, 27 figure

Métodos de alimentación alternativa para recién-nacidos prematuros

OBJECTIVE: To present a literature review about the use of glass/cup as an alternative method of feeding premature newborns and to identify if there is a consensus on its indication for this population. DATA SOURCE: A narrative review of the literature. Articles were selected from Medline, Lilacs, SciELO, and Cochrane databases, regardless of year, using the following specific key-words: feeding, premature newborn, breastfeeding, feeding methods. DATA SYNTHESIS: Although some studies showed that feeding premature and term newborns using the glass/cup is safe and efficient, most of them did not apply an objective evaluation of the swallowing to identify the effect of the method in this population. CONCLUSIONS: There is no consensus in the literature about feeding premature newborn infants by glass/cup. Controlled studies should be conducted in order to evaluate risks and benefits of alternative feeding methods in preterm newborn infants.OBJETIVO: Presentar revisión de literatura sobre el uso de vaso/taza como método alternativo de alimentación para recién-nacidos prematuros y verificar si hay consenso sobre su indicación para esta población. FUENTES DE DATOS: Revisión de literatura narrativa, habiendo sido seleccionados artículos en las bases de datos Medline, Lilacs, SciELO y Cochrane, independientemente del año, usando descriptores específicos: alimentación artificial, recién-nacido prematuro, lactancia materna, métodos de alimentación. SÍNTESIS DE LOS DATOS: Aunque algunos estudios afirmen que el método vaso/taza es eficaz y seguro para alimentar a recién-nacidos pre-término y a término, tales estudios no evalúan de modo objetivo el efecto del método sobre la deglución de estos pacientes. CONCLUSIONES: Se verificó que no hay consenso en la literatura respecto a la complementación de la alimentación de recién-nacidos prematuros mediante vaso/taza. Se debe realizar estudios controlados con la finalidad de rever riesgos y beneficios del uso de métodos alternativos en la alimentación del recién-nacido prematuro.OBJETIVO: Apresentar revisão de literatura sobre o uso do copo/xícara como método alternativo de alimentação para recém-nascidos prematuros e verificar se há consenso sobre sua indicação para essa população. FONTES DE DADOS: Revisão de literatura narrativa, tendo sido selecionados artigos nas bases de dados Medline, Lilacs, SciELO e Cochrane, independentemente do ano, usando descritores específicos: alimentação artificial, recém-nascido prematuro, aleitamento materno, métodos de alimentação. SÍNTESE DOS DADOS: Apesar de alguns estudos afirmarem que o método do copo/xícara é eficaz e seguro para alimentar recém-nascidos pré-termo e a termo, tais estudos não avaliam de forma objetiva o efeito do método sobre a deglutição desses pacientes. CONCLUSÕES: Verificou-se não haver consenso na literatura quanto à complementação da alimentação de recém-nascidos prematuros por meio do copo/xícara. Estudos controlados devem ser realizados com a finalidade de rever riscos e benefícios do uso de métodos alternativos na alimentação do recém-nascido prematuro.Universidade Federal de São Paulo (UNIFESP)Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de FonoaudiologiaUNIFESPSciEL

Collapse and Revival in Holographic Quenches

We study holographic models related to global quantum quenches in finite size systems. The holographic set up describes naturally a CFT, which we consider on a circle and a sphere. The enhanced symmetry of the conformal group on the circle motivates us to compare the evolution in both cases. Depending on the initial conditions, the dual geometry exhibits oscillations that we holographically interpret as revivals of the initial field theory state. On the sphere, this only happens when the energy density created by the quench is small compared to the system size. However on the circle considerably larger energy densities are compatible with revivals. Two different timescales emerge in this latter case. A collapse time, when the system appears to have dephased, and the revival time, when after rephasing the initial state is partially recovered. The ratio of these two times depends upon the initial conditions in a similar way to what is observed in some experimental setups exhibiting collapse and revivals

Sistemas Agroflorestais no entorno de Parques Nacionais: o caso do Parque Nacional do Iguaçu

Trabalho de Conclusão de Curso apresentado ao Instituto Latino- Americano de Economia, sociedade e política da Universidade Federal da Integração Latino-Americana, como requisito parcial à obtenção do título de Bacharel em Desenvolvimento Rural e Segurança Alimentar Orientadora: Prof. Ana Alice EleutérioO presente trabalho investiga a adoção de técnicas agroflorestais, após um curso sobre o tema, ser ministrado no Colégio Agrícola de Foz do Iguaçu, em dezembro de 2017, para agricultores do entorno do Parque Nacional do Iguaçu. O objetivo deste trabalho foi apurar a adaptabilidade e o interesse dos agricultores em adotar o sistema agroflorestal como método de produção em sua propriedade, de modo a promover o desenvolvimento territorial, revelando contiguamente a vantagem aos parques nacionais em fomentar este tipo de técnica agrícola em seu entorno. Para alcançar tais objetivos foram utilizadas referências bibliográficas relacionadas ao tema e aplicação de um questionário aos participantes do curso. O estudo concluiu que há uma potencialidade latente para o desenvolvimento de sistemas agroflorestais na região.The present work investigates the endorsement of agroforestry techniques, after a course on the subject was taught at the Agricultural College of Foz do Iguaçu, in December 2017, for small scale landowners in the vicinity of the Iguaçu National Park. In order to determine the adaptability and interest on embracing the agroforestry system as a method of production on their property, contiguously revealing the advantage to national parks in promoting this type of agricultural technique on their surroundings. To achieve these objectives, bibliographical references related to the topic and application of a questionnaire to course participants were used. The study concludes a latent potentiality for the development of agroforestry systems in the regio

Die Natur und das Verhalten von Edelgasatomen auf Metalloberflaechen

Diese Dissertation beschaeftigt sich mit dem Verhalten von Edelgasatomen auf Metalloberflaechen, welches traditionsgemaess in der Festkoerperphysik als Modellsysteme dient. Weiterhin stellen auf der Metalloberflaeche adsorbierte Edelgasatome ein Musterbeispiel fuer die schwache Wechselwirkung, die Physisorption, dar. In Anbetracht der Natur der Edelgasatome, insbesondere ihrer abgeschlossenen Schalen, wird ueblicherweise angenommen, dass van der Waals Anziehung und Pauli Abstossung die Hauptwechselwirkungen, welche es zu beruecksichtigen gilt, sind. Ausgehend von diesem Bild und der Erwartung, dass Edelgasadsorbate auf Metalloberflaechen im allgemeinen ungerichtete Adsorbat-Substrat-Bindungen bilden, wird angenommen, dass Xe-Atome bevorzugt auf hochkoordinierten Plaetzen adsorbieren, z.B. auf fcc und hcp Plaetzen der dicht gepackten Oberflaechen. Man sah dieses Bild durch Untersuchungen mittels spinpolarisierter Elektronenbeugung (LEED) an Xe-Atomen, die auf Pd(111) und Pt(111) adsorbiert sind, und durch theoretische Berechnungen unter Verwendung von Lennard--Jones Paarpotentialen, z.B. an Xe Adatomen auf der Ni(110) Oberflaeche, bestaetigt. Vor etwa 10 Jahren wurde jedoch vorgeschlagen, dass Xe-Atome auf niedrig-koordinierten top-Plaetzen, anstatt auf den hochkoordinieren Muldenplaetzen, adsorbieren. Diese ueberraschende und im allgemeinen nicht akzeptierte Behauptung basiert auf Beugungsdaten von Heliumatomen an der bei tiefen Temperaturen uniaxial komprimierten Phase der Xe-Adatomen auf Pt(111). Die Bevorzugung der top-Positionen wurde jedoch kuerzlich durch LEED Intensitaetanalysen von Xe-Atomen, adsorbiert auf Cu(111), Ru(0001), Pd(111) und Pt(111) in der $(sqrt{3} imes sqrt{3})R30^{circ}$ Struktur, bestaetigt. Es wurde nun spekuliert, dass im Gegensatz zum akzeptierten van der Waals und Pauli-Abstossungs-Bild, ein kovalenter Beitrag zur Bindung die top-Platz-Praeferenz verursacht. Folglich wurden, trotz der vermeintlichen "Einfachheit" der Edelgas/Metall-Systeme, sogar ganz grundlegende Fragen nicht zufriedenstellend beantwortet: Welcher ist der bevorzugte Adsorptionsplatz und wieso gerade dieser? Was ist die Natur der Adsorbat-Substrat-Bindung? Um die mikroskopische Natur der Wechselwirkung zwischen Xe-Atomen und Uebergangsmetalloberflaechen zu bestimmen, um die bevorzugten Adsorptionsplaetze zu ermitteln und konsistent zu erklaeren, sowie ein verbessertes Verstaendnis der Wechselwirkung zwischen Edelgasatomen und Metalloberflaechen zu erlangen, wurden in dieser Arbeit Dichtefunktionalrechnungen innerhalb der lokalen Dichtenaeherung und der Gradienten-korrigierten Naeherung, unter Verwendung der All-Elektronen {it Full-Potential Linearized Augmented Plane Wave} Methode fuer die Systeme Ar/Pd(111), Kr/Pd(111), Xe/Mg(0001), Xe/Al(111), Xe/Ti(0001), Xe/Cu(111), Xe/Pd(111) und Xe/Pt(111) durchgefuehrt. Es wurde gefunden, dass Xe-Adatome bei verschiedenen Bedeckungen, z.B. $Theta_{ m Xe}$ $=$ $1/3$, $1/4$ und $1/9$, bevorzugt an niedrig-koordinierten top-Plaetzen der Übergangsmetalle aber auch an einfachen freie-Elektonen Metallen bei $Theta_{ m Xe}$ $=$ $1/3$ binden. Weiter wird gefunden, dass Ar- und Kr-Adatome bei $Theta_{ m Ar}$ $=$ $Theta_{ m Kr}$ $=$ $1/3$ auf der Pd(111) Oberflaeche auf den top-Plaetzen adsorbieren. Daher binden Edelgas Adatome bevorzugt auf top-Plaetzen der basalen Metalloberflaechen. Desweiteren wurde ermittelt, dass die Xe Adatom-Adatom Wechselwirkung auf Pt(111) und Pd(111) abstossend ist. Geometrische Daten, die aus der Adsorbat-Substrat-Gleichgewichtsgeometrien abgeleitet wurden, werden im Detail diskutiert. Bezueglich der mikroskopischen Natur des Wechselwirkungsmechanismus zwischen Edelgasatomen und Metalloberflaechen wurden folgende Schluesse gezogen: (i) die Pauli Abstossung ist Platz-abhaengig. Sie ist schwaecher fuer Edelgasatome, die auf top-Positionen der Metalloberflaeche adsorbiert sind; (ii) es wurde gefunden, dass das Edelgas-Adatom polarisiert wird, wenn es sich der Oberflaeche naehert, was zu einem induzierten Dipolmoment fuehrt, welches fast auf dem Adsorbat lokalisiert ist und von der Oberflaeche weg weist. Somit kann die Erniedrigung der Austrittsarbeit der Metalloberflaeche bei Adsorption eines Edelgasatoms erklaert werden. Die Bevorzugung der top-Position wird durch die staerkere Polarisation und die schwaechere Pauli Abstossung fuer Edelgasatome auf top-Positionen bestimmt. Die am Wechselwirkungsmechanismus beteiligten Adsorbat- und Substrat-Orbitale sowie der Ursprung des induzierten Dipolmoments wurden indentifiziert und werden im Detail in dieser Arbeit diskutiert. Das beschriebene mikroskopische Bild der Wechselwirkung zwischen Edelgasatom und Metalloberflaeche ist allgemein, in dem Sinne, dass es auf andere Uebergangsmetalle und freie-Elektron-Metall-Substrate angewandt werden kann.This dissertation focuses on the behavior of rare-gas atoms on metal surfaces, which have a long tradition in serving as model systems in condensed matter physics. Furthermore, rare-gas atoms adsorbed on metal surfaces represent a paradigm of weak adsorption, i.e., physisorption. Noting the nature of the rare-gas atoms, in particular, that they have close shells, it is typically assumed that the main interactions at play are the van der Waals attraction and Pauli repulsion. From this picture and because of the fact that rare-gas adsorbates on metal surfaces are generally expected to form non-directional adsorbate-substrate bonds, it has been assumed that Xe atoms preferentially adsorb on highly coordinated sites, e.g., fcc and hcp sites on the terraces of close-packed surfaces. This picture was thought to be confirmed by spin-polarized low-energy electron diffraction (LEED) studies of Xe atoms adsorbed on the Pd(111) and Pt(111) surfaces and by theoretical calculations employing the interatomic Lennard-Jones pair potential, e.g., Xe adatoms on the Ni(110) surface. However about ten years ago, based on helium atom diffraction data from the low-temperature uniaxially compressed phase of Xe adatoms on Pt(111), it was argued that Xe atoms adsorb in low coordination on-top sites instead of the expected high coordination hollow sites; a quite surprising, widely not accepted suggestion. The on-top site preference, however, was recently confirmed by LEED intensity analyses for Xe atoms adsorbed on the Cu(111), Ru(0001), Pd(111), and Pt(111) surfaces in the commensurate $(sqrt{3} imes sqrt{3})R30^{circ}$ structure. It was speculated, in contrast to the typically accepted van der Waals and Pauli repulsion picture, that a covalent contribution to the binding determines the on-top Xe adsorption site preference. Thus, despite the conceived ''simplicity'' of the rare-gas/metal systems, even the most basic questions have not been answered satisfactorily: What is the adsorption site and {it why} is it what it is? and what is the nature of the adsorbate-substrate bond? To determine the microscopic nature of the interaction between Xe atoms and transition metal surfaces, hence, to determine the adsorption site preference and explain it consistently, as well as to provide an improved understanding of the interaction between rare-gas atoms and metal surfaces, density functional theory within local-density and generalized gradient approximations calculations employing the all-electron full-potential linearized augmented plane wave method for the Ar/Pd(111), Kr/Pd(111), Xe/Mg(0001), Xe/Al(111), Xe/Ti(0001), Xe/Cu(111), Xe/Pd(111), and Xe/Pt(111) systems were performed in the present thesis. It is found that Xe adatoms preferentially bind at low coordination on-top sites on transition metal surfaces for different Xe coverages, i.e., $Theta_{ m Xe} = 1/3$, $1/4$ and $1/9$, as well as on simple free-electron-like metal surfaces at $Theta_{ m Xe} = 1/3$. Furthermore, it is found that Ar and Kr adatoms adsorb in the on-top sites on the Pd(111) surface at $Theta_{ m Ar}$ $=$ $Theta_{ m Kr} = 1/3$. Therefore, rare-gas adatoms preferentially bind in the on-top sites on close-packed metal surfaces. Furthermore, it is was obtained that the Xe adatom-adatom interaction is repulsive for Xe adatoms on the Pt(111) and Pd(111) surfaces. The geometrical parameters derived at the equilibrium adsorbate-substrate geometry were calculated and are discussed in detail in the thesis. With respect to the microscopic nature of the interaction mechanism between rare-gas atoms and metal surfaces, the following conclusions were obtained: $(i)$ the Pauli repulsion is site-dependent, and it is weaker for rare-gas atoms adsorbed in the on-top site on metal surfaces; $(ii)$ it is found that the rare-gas adatom polarizes as it approaches the surface, which gives rise to an induced dipole moment almost located on the adsorbate and pointing out of the surface; thus, it explains the work function decrease of the metal substrate upon rare-gas adsorption. The on-top site preference is determined by the stronger polarization and weaker Pauli repulsion for rare-gas adatoms in the on-top sites. The adsorbate and substrate orbitals involved in the interaction mechanism, as well as the origin of the induced dipole moment, were identified and are discussed in detail in the thesis. The described microscopic picture for the interaction between rare-gas atoms and metal surfaces is general, in the sense that it can be applied to other transition metal and free-electron-like metal substrates

A LEGITIMIDADE DOS CONCURSOS PÚBLICOS REALIZADOS PELAS INSTITUIÇÕES FEDERAIS DE ENSINO SUPERIOR PARA O CARGO DE SECRETÁRIO-EXECUTIVO

Este artigo apresenta uma análise dos concursos públicos realizados pelas Instituições Federais de Ensino Superior (IFES), no período de 2010 a 2014, para o provimento do cargo de secretário-executivo. O objetivo foi compreender se as provas aplicadas aos candidatos têm sido legítimas no sentido de contemplar conteúdos constantes na descrição do cargo, leis de regulamentação da profissão, diretrizes e grades curriculares dos cursos superiores de Secretariado, de modo que selecionem profissionais que possam atender às necessidades dessas instituições. Os dados, obtidos por meio de uma análise predominantemente quantitativa, demonstraram que as IFES não têm considerado a formação do secretário-executivo de maneira significativa na construção dessas provas e tampouco têm elaborado questões diretamente associadas à descrição do cargo. Concluiu-se que, de modo geral, os concursos abrangidos pelo recorte da pesquisa não mensuraram os conhecimentos requeridos para o bom desempenho das funções desses profissionais, assim como não utilizaram instrumentos que permitissem avaliar suas habilidades e comportamentos. Nesse sentido, foram ineficazes na identificação de competências e podem ter limitado a seleção de candidatos com alto potencial de contribuição