Intermittent many-body dynamics at equilibrium

The equilibrium value of an observable defines a manifold in the phase space of an ergodic and equipartitioned many-body system. A typical trajectory pierces that manifold infinitely often as time goes to infinity. We use these piercings to measure both the relaxation time of the lowest frequency eigenmode of the Fermi-Pasta-Ulam chain, as well as the fluctuations of the subsequent dynamics in equilibrium. The dynamics in equilibrium is characterized by a power-law distribution of excursion times far off equilibrium, with diverging variance. Long excursions arise from sticky dynamics close to q-breathers localized in normal mode space. Measuring the exponent allows one to predict the transition into nonergodic dynamics. We generalize our method to Klein-Gordon lattices where the sticky dynamics is due to discrete breathers localized in real space.We thank P. Jeszinszki and I. Vakulchyk for helpful discussions on computational aspects. The authors acknowledge financial support from IBS (Project Code No. IBS-R024-D1). (IBS-R024-D1 - IBS)Published versio

Flat Bands Under Correlated Perturbations

Flat band networks are characterized by coexistence of dispersive and flat bands. Flat bands (FB) are generated by compact localized eigenstates (CLS) with local network symmetries, based on destructive interference. Correlated disorder and quasiperiodic potentials hybridize CLS without additional renormalization, yet with surprising consequencies: (i) states are expelled from the FB energy $E_{FB}$, (ii) the localization length of eigenstates vanishes as $\xi \sim 1 / \ln (E- E_{FB})$, (iii) the density of states diverges logarithmically (particle-hole symmetry) and algebraically (no particle-hole symmetry), (iv) mobility edge curves show algebraic singularities at $E_{FB}$. Our analytical results are based on perturbative expansions of the CLS, and supported by numerical data in one and two lattice dimensions

Towards a time-reversal mirror for quantum systems

The reversion of the time evolution of a quantum state can be achieved by changing the sign of the Hamiltonian as in the polarization echo experiment in NMR. In this work we describe an alternative mechanism inspired by the acoustic time reversal mirror. By solving the inverse time problem in a discrete space we develop a new procedure, the perfect inverse filter. It achieves the exact time reversion in a given region by reinjecting a prescribed wave function at its periphery.Comment: 6 pages, 4 figures. Introduction modified, references added, one figure added to improve the discussio

ELVES IV: The Satellite Stellar-to-Halo Mass Relation Beyond the Milky-Way

Quantifying the connection between galaxies and their host dark matter halos has been key for testing cosmological models on various scales. Below $M_\star \sim 10^9\,M_\odot$, such studies have primarily relied on the satellite galaxy population orbiting the Milky Way. Here we present new constraints on the connection between satellite galaxies and their host dark matter subhalos using the largest sample of satellite galaxies in the Local Volume ($D \lesssim 12\,\mathrm{Mpc}$) to date. We use $250$ confirmed and $71$ candidate dwarf satellites around 27 Milky Way (MW)-like hosts from the Exploration of Local VolumE Satellites (ELVES) Survey and use the semi-analytical SatGen model for predicting the population of dark matter subhalos expected in the same volume. Through a Bayesian model comparison of the observed and the forward-modeled satellite stellar mass functions (SSMF), we infer the satellite stellar-to-halo mass relation. We find that the observed SSMF is best reproduced when subhalos at the low mass end are populated by a relation of the form $M_\star \propto M^\alpha_\mathrm{peak}$, with a moderate slope of $\alpha_\mathrm{const}=2.10 \pm 0.01$ and a low scatter, constant as a function of the peak halo mass, of $\sigma_\mathrm{const}=0.06^{+0.07}_{-0.05}$. A model with a steeper slope ($\alpha_\mathrm{grow}=2.39 \pm 0.06$) and a scatter that grows with decreasing $M_\mathrm{peak}$ is also consistent with the observed SSMF but is not required. Our new model for the satellite-subhalo connection, based on hundreds of Local Volume satellite galaxies, is in line with what was previously derived using only the Milky Way satellites.Comment: Accepted for publication in ApJ. Figure 8 shows the key result -- the Satellite Stellar to Halo Mass relation obtained in this work, in comparison to previous studie

Histone Deacetylase and Microtubules as Targets for the Synthesis of Releasable Conjugate Compounds

Design and synthesis of an HDAC inhibitor and its merger with three tubulin binders to create releasable conjugate compounds is described. The biological evaluation includes: a) in vitro reactivity with glutathione, b) antiproliferative activity, c) cell cycle analysis and d) quantification of protein acetylation. The cellular pharmacology study indicated that the HDAC-inhibitor-drug conjugates retained antimitotic and proapoptotic activity with a reduced potenc

Compact Discrete Breathers on Flat Band Networks

Linear wave equations on flat band networks host compact localized eigenstates (CLS). Nonlinear wave equations on translationally invariant flat band networks can host compact discrete breathers - time periodic and spatially compact localized solutions. Such solutions can appear as one-parameter families of continued linear compact eigenstates, or as discrete sets on families of non-compact discrete breathers, or even on purely dispersive networks with fine-tuned nonlinear dispersion. In all cases, their existence relies on destructive interference. We use CLS amplitude distribution properties and orthogonality conditions to derive existence criteria and stability properties for compact discrete breathers as continued CLS.Comment: 12 pages, 6 figure

Relação entre o provimento do cargo de diretor/a e a qualidade da educação: análise das condições de oferta e resultados escolares / Relationship between the appointment of the diretor and the quality of education: analysis of the conditions of offer and school results

O presente artigo tem por objetivo aproximar a forma de provimento dos/as diretores/as com as condições de oferta e resultados escolares, delimitando a discussão para os anos iniciais do Ensino Fundamental, separados em dois grupos de redes municipais: a) um somente com diretores/as no qual a forma de provimento foi por indicação e; b) outro com dirigentes eleitos pela comunidade. Na discussão da literatura acadêmica, se enfatiza a importância da gestão democrática e, consequentemente, a forma de provimento do/a diretor/a por eleição pela comunidade escolar, como valor agregado à melhoria da qualidade da educação.Em metodologia de análise dos dados, utilizou-se os questionários de contexto dos anos iniciais da Prova Brasil de 2013 e estudos de análise da gestão democrática, baseados em indicadores desenvolvidos para este fim, como elemento condicionante na qualidade da educação, permitindo uma aproximação com a realidade local das redes municipais contempladas na pesquisa. Analisou-se ainda, os resultados do Índice de Desenvolvimento da Educação Básica de 2013, desagregando-o e trabalhando as proficiências em Língua Portuguesa e Matemática, além das taxas de aprovação, dados dos anos iniciais do Ensino Fundamental, analisando comparativamente os dois grupos.Evidenciou-se diferença em todas as dimensões analisadas, favorecendo os resultados quantitativos para o conjunto de redes municipais em que os diretores/as foram eleitos pela comunidade escolar, onde os resultados são de maior homogeneidade, maiores Ideb, proficiências, taxas de aprovação dos anos iniciais do EF e condições de oferta mais privilegiadas, se comparadas com o grupo de redes municipais com diretores/as em que a forma de provimento foi somente por indicação.Ademais, tratam-se de resultados empíricos que possivelmente fomentem novas discussões acerca da temática proposta e, consequentemente, o papel da gestão democrática na qualidade da oferta educacional

As formas de escolha dos diretores das escolas de educação infantil nas redes municipais das capitais brasileiras

O presente artigo teve por objetivo revelar e discutir a forma de escolha dos diretores que atuam nas escolas que atendem exclusivamente a educação infantil nas capitais brasileiras e em Brasília. Para tanto, a metodologia empregada consistiu em uma análise documental que pudesse fornecer informações para a construção desse panorama, consultando páginas na Internet das Prefeituras, Governo Distrital, Conselhos Municipais/Distrital de Educação e Câmara dos Vereadores/Câmara Legislativa. Pautado na literatura voltada à discussão sobre a gestão democrática do ensino público brasileiro e nos princípios e apontamentos do tema na legislação nacional vigente, o resultado da pesquisa mostrou que 41% das capitais realizam o processo de escolha por eleição, 7% por indicação, 4% por concurso público e outras 7% utilizam modelos mistos. Destacamos ainda a dificuldade de acesso à informação deste ato público, pois em 41% das capitais não encontramos nenhuma informação em sites oficiais sobre a forma de escolha de seus diretores

Quantitative and Qualitative Assessments of Retinal Structure with Variable A-Scan Rate Spectralis OCT: Insights into IPL Multilaminarity

The aim of this study was to evaluate the qualitative and quantitative differences between 20 and 85 kHz A-scan rate optical coherence tomography (OCT) images acquired by spectral domain OCT. The study included 60 healthy subjects analyzed with horizontal linear scans with a variable A-scan rate (SHIFT technology, Heidelberg Engineering, Heidelberg, Germany). The retinal thickness measurement of each retinal layer was performed in three different positions (subfoveal, nasal, and temporal). The qualitative assessment was performed by two independent observers who rated every image with a score ranging from 1 ("sufficient") to 3 ("excellent") on the basis of three parameters: visualization of the vitreo-retinal interface, characterization of the retinal layers, and visualization of the sclero-choroidal interface. No statistically significant differences in terms of retinal layer thickness between the two A-scan rate scans were observed (p > 0.05). The coefficient of variation of the retinal thickness values was lower in the 20 kHz group (25.8% versus 30.1% with the 85 kHz). The 20 kHz images showed a higher quality index for both observers. An inner plexiform layer (IPL) multilaminarity was detected in 78.3% of patients from the 20 kHz group and in 40% of patients from the 85 kHz group (p < 0.05)