Dirac points merging and wandering in a model Chern insulator

We present a model for a Chern insulator on the square lattice with complex first and second neighbor hoppings and a sublattice potential which displays an unexpectedly rich physics. Similarly to the celebrated Haldane model, the proposed Chern insulator has two topologically non-trivial phases with Chern numbers $\pm1$. As a distinctive feature of the present model, phase transitions are associated to Dirac points that can move, merge and split in momentum space, at odds with Haldane's Chern insulator where Dirac points are bound to the corners of the hexagonal Brillouin zone. Additionally, the obtained phase diagram reveals a peculiar phase transition line between two distinct topological phases, in contrast to the Haldane model where such transition is reduced to a point with zero sublattice potential. The model is amenable to be simulated in optical lattices, facilitating the study of phase transitions between two distinct topological phases and the experimental analysis of Dirac points merging and wandering

Simpler is better: a novel genetic algorithm to induce compact multi-label chain classifiers

Multi-label classification (MLC) is the task of assigning multiple class labels to an object based on the features that describe the object. One of the most effective MLC methods is known as Classifier Chains (CC). This approach consists in training q binary classifiers linked in a chain, y1 → y2 → ... → yq, with each responsible for classifying a specific label in {l1, l2, ..., lq}. The chaining mechanism allows each individual classifier to incorporate the predictions of the previous ones as additional information at classification time. Thus, possible correlations among labels can be automatically exploited. Nevertheless, CC suffers from two important drawbacks: (i) the label ordering is decided at random, although it usually has a strong effect on predictive accuracy; (ii) all labels are inserted into the chain, although some of them might carry irrelevant information to discriminate the others. In this paper we tackle both problems at once, by proposing a novel genetic algorithm capable of searching for a single optimized label ordering, while at the same time taking into consideration the utilization of partial chains. Experiments on benchmark datasets demonstrate that our approach is able to produce models that are both simpler and more accurate

Polirradiculoneuropatia desmielinizante inflamatória aguda (síndrome de Guillain-Barré) após dengue

Este trabalho relata o caso de uma criança, sexo feminino, seis anos que desenvolveu subitamente cefaléia lancinante, febre, mialgia e paresia. Os exames de investigação clínica, que incluíram hemograma, contagem de plaquetas, dosagens bioquímicas (uréia, creatinina, transferases e billirrubina total e frações) e por títulos específicos de IgM, por enzima-imunoensaio (EIA) com antígeno tetravalente de dengue. Após dez dias de internação e já em ambiente domiciliar, novo quadro clínico surgiu caracterizado por disfagia, disfonia, paresia, paralisia facial periférica e parestesias. O diagnóstico do dengue e da Síndrome de Guillain-Barré foi baseado nos achados clínicos, no exame do líquido cefalorraquidiano, achados eletrofisiológicos e na exclusão de outras patologias. Neste caso, como em alguns relato anteriores, chama a atenção para a possibilidade de que Síndrome de Guillain-Barré pode ocorrer em associação com a dengue.This paper reports a case of dengue in a six-year-old female child who suddenly developed excruciating headaches, fever, myalgia and paresis. Laboratory examinations included blood count, platelet count, biochemical tests (BUN, creatinine, aminotransferases, and total bilirubin and bilirubin fractions) and specific IgM titers (enzyme-immunoassay with recombinant tetravalent dengue). After ten days of hospitalization and having already been in a home environment, a new clinical image emerged, characterized by dysphagia, dysphonia, weakness, peripheral facial palsy and paresthesia. The diagnosis of Guillain-Barré Syndrome was based on clinical findings, cerebrospinal fluid examination, electrophysiological findings and the exclusion of other pathologies. Our case, as some shown in previous reports, calls attention to the possibility that Guillain-Barré Syndrome may occur in association with dengue

A distribuição espacial da atividade inovadora brasileira: uma análise exploratória

The aim of this paper is to analyze the spatial distribution of innovation, measured as per capita patents, in geographical microregions of Brazil. This purpose is achieved by using exploratory spatial data analysis. This paper is pioneer in adopting this set of statistical tools when we look at the Brazilian innovation literature. Our findings reveal that the per capita patents are distributed nonrandomly, suggesting positive spatial autocorrelation. The spatial heterogeneity confirms the existence of North-South polarization regime in terms of technological activity in Brazil. Local indicators of spatial association are also computed as well as bivariate Moran statistics as means of assessing the influence of neighborhood on each microregion’s technological performance. We find out that lack of some elements such as industrialization, higher-educated population, PhD researchers, workers with technological background, and technological and industrial diversity in a microregion may be working as spatial barriers, thus precluding the diffusion process of knowledge spillovers.exploratory spatial data analysis, per capita patents, spatial autocorrelation, spatial regimes, Brazil

A Quantification of the Rhythmic Qualities of Salience and Kinesis

From a cognitive point of view, it is easily perceived that some music rhythmic structures are able to create saliences (i.e. pulses perceived as louder). Depending where in a metrical grid these salient pulses are located, a sense of stability or instability will arise. When instability is present in a rhythmic structure one will tend to psychological feel kinesis (i.e. a sense of motion). Salience and kinesis can then be identified as basic rhythmic qualities. Inspired by the theoretical construct Just in Time - an empirical based music theoretical construct for the analysis of rhythm - we decided to quantify some of its analytical output; more specifically the measure of salience and kinesis of a rhythmic sequence. We then developed a web-based tool that calculates the amount of salience and kinesis for a particular rhythmic sequence. We conclude this article pointing how this tool can be used in analysis and music education as well as other possible applications, and future research

Wine routes and regional development

[Resumo] Vinho e turismo constituem hoje dois produtos cada vez mais complementares,mormente em regiões vitivinícolas deprimidas e que encetaram processos de restruturaçãocom a introdução da componente turística. Estamos, assim, perante duas componentes determinadasa partir do contexto territorial, porquanto quer a regulamentação e certificaçãodo vinho parte de pressupostos regionais – a região demarcada – e o turismo que se articulacom o desenho e a atracção do destino – local ou regional – exercida sobre o turista. Esta associaçãodo vinho ao turismo implica ainda a valorização da “marca” onde o ênfase regional vaicontribuir, sobremaneira, para o desenvolvimento e a sustentabilidade da região.Assim, o enoturismo representa actualmente mais do que uma motivação específica para arealização da viagem induzida pelo vinho, ele constitui uma nova oportunidade de negócio eum catalisador para a economia de uma região vitivinícola. A par, pode igualmente contribuirpara o “afinar do destino turístico”, pois passa a promover a região e um conjunto de actividadesassociadas ao vinho.Por conseguinte, o sucesso de um destino enoturístico e o desenho das rotas vitícolas estãosimultaneamente associados à reputação do vinho da região, à organização da adega e aoacolhimento dos visitantes, à dinamização e promoção dos elementos endógenos e do único,á criação de um conjunto de serviços, atracções e eventos que permitem complementar aadega e qualificar a região enquanto produto”turismo integrado numa matriz cultural.[Abstract] Wine and tourism are two products today increasingly complementary, especially in depressedand wine regions that have depressed upon restructuring with the introduction oftourism component. Moreover, these two components can be determined from the territorialcontext, because both the regulations and certification of the wine part of regional assumptions- the demarcated region - tourism and, in turn, is linked to the design and attractivenessof destination - local or regional - exerted on the tourist. This association of wine to tourismalso implies the recognition of the “brand” where the regional emphasis will greatly contributeto the development and sustainability of the region.Thus, wine tourism currently represents more than a specific motivation for holding the winedriven trip, it is a new business opportunity and a catalyst for the economy of a wine region.At the same time, it can also contribute to “fine tune the tourist destination”, as it starts to promotethe region and a range of activities associated with wine.Therefore, the success of a wine tourism destination and the design of wine routes are both associatedwith the reputation of the region’s wine, the organization of the cellar and the receptionof visitors, the stimulation and promotion of endogenous elements and of the “unique”,will create a set of services, attractions and events that allow to complement the winery and toqualify the region as an integrated tourist product.[Resumen] Vino y turismo constituyen hoy dos productos cada vez más complementarios, especialmenteen las regiones vitivinícolas deprimidas y que han emprendido procesos de reestructuracióncon la introducción del componente turístico. Además, estos dos componentespueden ser determinados a partir del contexto territorial, por cuanto la regulación y la certificacióndel vino parte de presupuestos regionales –la región demarcada- y el turismo, asu vez, se articula con el diseño y el atractivo del destino –local o regional- ejercido sobreel turista. Esta asociación de vino y turismo implica el reconocimiento de la “marca”, dondeel énfasis regional contribuirá, en gran medida, al desarrollo y la sostenibilidad de la región.Así, el enoturismo representa actualmente más que una motivación específica para la realizacióndel viaje inducido por el vino, al constituir una nueva oportunidad de negocio y uncatalizador para la economía de una región vitivinícola. Además, puede contribuir igualmentea “afinar el destino turístico”, pues pasa a promover la región y un conjunto de actividadesasociadas al vino.Por consiguiente, el éxito de un destino enoturístico y el diseño de rutas vitícolas están simultáneamenteasociados a la reputación del vino de la región, a la organización de la bodega y ala recepción de los visitantes, la dinamización y promoción de los elementos endógenos y delo “único”, la creación de un conjunto de servicios, atracciones y eventos que permitan complementarla bodega y calificar la región en cuanto producto turístico integrado

Two-ballot versus plurality rule: an empirical investigation on the number of candidates

Duverger claimed more than 50 years ago that the number of candidates in elections should be a function of electoral rules. Both his “law” and “hypothesis” suggest the number of candidates vying for seats in elections to be tightly linked to characteristics of the electoral process such as its degree of proportionality and the presence of runoffs. Here we test the validity of Duverger’s claim using data from municipal elections in Brazil. Our study differs from others in the field in two important dimensions. First, by using municipal data we avoid the usual problems that plague statistical analysis using cross-country data. Secondly, we have a truly exogenous source of variation due to a change in electoral legislation introduced by the constitutional reform of 1988: simple plurality remained the rule only in municipalities with less than 200,000 voters, and a second-ballot became mandatory for the others above that threshold. This allows for a neat identification strategy using panel data. Our main finding is that elections with runoffs lure greater numbers of candidates in municipalities with sufficiently high levels of heterogeneity.Duverger's law, runoff, heterogeneity