Bocal: Improvisação vocal e performance

This article reflects on the work Bocal presented in November 2021 at the 34th Bienal de São Paulo, at the invitation of the Novas Frequências festival and the Cultura Artística organization. It is a vocal improvisation duo performed by artists Inés Terra and Paola Ribeiro. From the experience of improvisation in the mentioned event and conversations stimulated by readings linked to the study of voice in improvised music and performance art, the artists discuss their practices and possible perceptions of the work, confronting the initial ideas that configured it. and elaborations subsequent to its realization, contributing to the understanding of the creation processes mediated by vocal exploration and its sociocultural paradigms.Este artículo reflexiona sobre el trabajo Bocal presentado en noviembre de 2021 en la 34ª Bienal de São Paulo, por invitación del Festival Novas Frequências y la organización Cultura Artística. Es un dúo de improvisación vocal realizado por las artistas Inés Terra y Paola Ribeiro. A partir de la experiencia de improvisación en el evento mencionado y conversaciones estimuladas por lecturas vinculadas al estudio de la voz en la música improvisada y la performance, las artistas discuten sus prácticas y posibles percepciones del trabajo, confrontando las ideas iniciales que lo configuraron y las elaboraciones posteriores a su realización, contribuyendo a la comprensión de los procesos de creación mediados por la exploración vocal y sus paradigmas socioculturales.Este artigo reflete sobre o trabalho Bocal  apresentado em novembro de 2021 na 34ª Bienal de São Paulo, a convite do Festival Novas Frequências e da organização Cultura Artística. Trata-se de um duo de improvisação vocal realizado pelas artistas Inés Terra e Paola Ribeiro. A partir da experiência de improvisação no evento mencionado e de conversas estimuladas por leituras ligadas ao estudo da voz na música improvisada e na arte da performance, as artistas discorrem sobre suas práticas e sobre as percepções possíveis do trabalho, confrontando as ideias iniciais que o configuraram e elaborações posteriores a sua realização, contribuindo com o entendimento dos processos de criação mediados pela exploração vocal e seus paradigmas socioculturais

Distributed Graph Clustering using Modularity and Map Equation

We study large-scale, distributed graph clustering. Given an undirected graph, our objective is to partition the nodes into disjoint sets called clusters. A cluster should contain many internal edges while being sparsely connected to other clusters. In the context of a social network, a cluster could be a group of friends. Modularity and map equation are established formalizations of this internally-dense-externally-sparse principle. We present two versions of a simple distributed algorithm to optimize both measures. They are based on Thrill, a distributed big data processing framework that implements an extended MapReduce model. The algorithms for the two measures, DSLM-Mod and DSLM-Map, differ only slightly. Adapting them for similar quality measures is straight-forward. We conduct an extensive experimental study on real-world graphs and on synthetic benchmark graphs with up to 68 billion edges. Our algorithms are fast while detecting clusterings similar to those detected by other sequential, parallel and distributed clustering algorithms. Compared to the distributed GossipMap algorithm, DSLM-Map needs less memory, is up to an order of magnitude faster and achieves better quality.Comment: 14 pages, 3 figures; v3: Camera ready for Euro-Par 2018, more details, more results; v2: extended experiments to include comparison with competing algorithms, shortened for submission to Euro-Par 201

Modificações microestruturais e tribológicas nos açosferramenta AISI H13 e DIN X100CrMoV 8-1-1 produzidas por nitretação a plasma

The tool-steels AISI H13 and DIN X100CrMoV 8-1-1, which are used for different applications, were plasma nitrided in a low concentration nitrogen atmosphere at 500°C in order to increase the wear resistance. Then, metallurgical properties of these steels before and after nitriding were evaluated, and wear tests were also performed. The results demonstrated that plasma nitriding successfully increased the wear resistance on both steels. This study also demonstrated how the modified properties contributed in this way. Key words: plasma nitriding, wear, H13, DIN X100CrMoV 8-1-1.Os acos-ferramenta AISI H13 e DIN X100CrMoV 8-1- 1, de características e aplicações distintas, foram nitretados a plasma em atmosfera de baixa concentração de nitrogênio a 500°C com o objetivo de incrementar a resistência ao desgaste. Em seguida, foi feita uma avaliação de propriedades metalúrgicas nos aços antes e após a nitretacão, e também foram feitos ensaios de desgaste. Os resultados demonstraram que a nitretacão a plasma foi eficiente em aumentar a resistência ao desgaste dos dois aços. O estudo também demonstrou como as propriedades modificadas contribuíram neste sentido. Palavras-chave: nitretacão a plasma, desgaste, H13, DIN X100CrMoV 8-1-1

Quantifying the interdisciplinarity of scientific journals and fields

There is an overall perception of increased interdisciplinarity in science, but this is difficult to confirm quantitatively owing to the lack of adequate methods to evaluate subjective phenomena. This is no different from the difficulties in establishing quantitative relationships in human and social sciences. In this paper we quantified the interdisciplinarity of scientific journals and science fields by using an entropy measurement based on the diversity of the subject categories of journals citing a specific journal. The methodology consisted in building citation networks using the Journal Citation Reports database, in which the nodes were journals and edges were established based on citations among journals. The overall network for the 11-year period (1999-2009) studied was small-world and scale free with regard to the in-strength. Upon visualizing the network topology an overall structure of the various science fields could be inferred, especially their interconnections. We confirmed quantitatively that science fields are becoming increasingly interdisciplinary, with the degree of interdisplinarity (i.e. entropy) correlating strongly with the in-strength of journals and with the impact factor.Comment: 23 pages, 6 figure

Evaluation of two interaction techniques for visualization of dynamic graphs

Several techniques for visualization of dynamic graphs are based on different spatial arrangements of a temporal sequence of node-link diagrams. Many studies in the literature have investigated the importance of maintaining the user's mental map across this temporal sequence, but usually each layout is considered as a static graph drawing and the effect of user interaction is disregarded. We conducted a task-based controlled experiment to assess the effectiveness of two basic interaction techniques: the adjustment of the layout stability and the highlighting of adjacent nodes and edges. We found that generally both interaction techniques increase accuracy, sometimes at the cost of longer completion times, and that the highlighting outclasses the stability adjustment for many tasks except the most complex ones.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

Prediction of lethal and synthetically lethal knock-outs in regulatory networks

The complex interactions involved in regulation of a cell's function are captured by its interaction graph. More often than not, detailed knowledge about enhancing or suppressive regulatory influences and cooperative effects is lacking and merely the presence or absence of directed interactions is known. Here we investigate to which extent such reduced information allows to forecast the effect of a knock-out or a combination of knock-outs. Specifically we ask in how far the lethality of eliminating nodes may be predicted by their network centrality, such as degree and betweenness, without knowing the function of the system. The function is taken as the ability to reproduce a fixed point under a discrete Boolean dynamics. We investigate two types of stochastically generated networks: fully random networks and structures grown with a mechanism of node duplication and subsequent divergence of interactions. On all networks we find that the out-degree is a good predictor of the lethality of a single node knock-out. For knock-outs of node pairs, the fraction of successors shared between the two knocked-out nodes (out-overlap) is a good predictor of synthetic lethality. Out-degree and out-overlap are locally defined and computationally simple centrality measures that provide a predictive power close to the optimal predictor.Comment: published version, 10 pages, 6 figures, 2 tables; supplement at http://www.bioinf.uni-leipzig.de/publications/supplements/11-01

A Statistical Performance Analysis of Graph Clustering Algorithms

Measuring graph clustering quality remains an open problem. Here, we introduce three statistical measures to address the problem. We empirically explore their behavior under a number of stress test scenarios and compare it to the commonly used modularity and conductance. Our measures are robust, immune to resolution limit, easy to intuitively interpret and also have a formal statistical interpretation. Our empirical stress test results confirm that our measures compare favorably to the established ones. In particular, they are shown to be more responsive to graph structure, less sensitive to sample size and breakdowns during numerical implementation and less sensitive to uncertainty in connectivity. These features are especially important in the context of larger data sets or when the data may contain errors in the connectivity patterns

ESTUDO ELETROQUÍMICO SOBRE A OXIDAÇÃO DE BIODIESEL

Objetivando a preservação ambiental e a melhoria do desempenho dos motores dos transportes, a Agência Nacional do Petróleo, Gás Natural e Biocombustíveis estabelece a adição obrigatória de biodiesel ao diesel mineral em uma proporção de 5% de biodiesel, em volume, ao diesel. Um dos parâmetros de qualidade é o período de indução, que está relacionado com a estabilidade oxidativa do biodiesel e é determinado pelo método Rancimat. A RANP 14/12 estabelece o período de indução mínimo de 6 h, queindica que o biocombustível será estável por até 6 meses de armazenamento. O presente trabalho propõe uma metodologia eletroquímica para estudar o comportamento oxidativo do biodiesel, utilizando a técnica voltametria cíclica. O biodiesel metílico de soja, sintetizado a partir da rota com catálise básica homogênea, apresentou período de indução 4,88 h e foi utilizado em todos os experimentos deste trabalho. Dentre os meios estudados para os ensaios voltamétricos, optou-se pelo meio orgânico, utilizando ácido nítrico como eletrólito de suporte. A metodologia proposta apresentou boa resposta à oxidação eletroquímica do biodiesel, devido à boa linearidade de crescimento da corrente de pico anódico com as adições da amostra, com coeficiente de correlação 0,996, para concentrações de até 10,66 mg.mL-1 de biodiesel. A partir da concentração de 12,44 mg.mL-1, observa-se uma pequena perda de linearidade, que pode ser atribuída à limitação do processo catalítico na superfície do eletrodo de ouro e à possível formação de um filme de poliacetonitrila. Os resultados obtidos no presente trabalho confirmam a viabilidade do método proposto para o estudo eletroquímico sobre a oxidação do biodiesel.Palavras-chave: Biodiesel. Estabilidade Oxidativa. Voltametria Cíclica.  ELECTROCHEMICAL STUDY ABOUT THE OXIDATION OF BIODIESELAbstract: Aiming environmental preservation and improvement on performance of engines transports, the Brazilian National Agency of Petroleum, Natural Gas and Biofuels establishes the mandatory addition of biodiesel to mineral diesel in Brazil, in a proportion of 5% of biodiesel, in volume, to diesel. One of the quality parameters of the biodiesel is the induction period, which is related to its oxidative stability, it being determined by the Rancimat method. The RANP no 14/2012 establishes a minimum value of 6 h for the induction period, which indicates that the biofuel will be stable for 6 months storage. This work proposes an electrochemical methodology to study oxidative behavior of biodiesel, using cyclic voltammetry technique. A methylic soybean biodiesel was synthesized through a basic catalysis homogeneous route, presenting an induction period of 4,88 h, which was utilized in all experiments of this work. Among all conditions evaluated for the voltammetric study, the organic middle was the chosen, using nitric acid as supporting electrolyte, because it presented the best voltammetric results, in terms of resolution and sensitivity. The proposed methodology presented a good response for the electrochemical oxidation study of biodiesel, due to the good linear relationship obtained between the anodic peak current and biodiesel concentration, with a correlation coefficient of 0,996, to concentrations until 10,66 mg.mL-1 of biodiesel. From concentration of 12,44 mg.mL-1, a small deviation from linearity is observed, which could be attributed to the limitation of the catalytic process on the gold electrode surface and to the possible formation of a polyacetonitrile film.The results obtained in the present work confirm the viability of the proposed method to the electrochemical study about oxidation of biodiesel.Keywords: Biodiesel. Oxidative Stability. Cyclic Voltammetry.  ESTUDIO ELECTROQUÍMICO SOBRE LA OXIDACIÓN DE BIODIESELResumen: Con el objetivo de preservar el medio ambiente y mejorar el desempeño de los motores de los transportes, la Agencia Nacional de Petróleo, Gas Natural y Biocombustibles establece la adición obligatoria de biodiesel al diesel mineral en una proporción de 5% de biodiesel, en volumen, de diesel. Uno de los parámetros de calidad es el período de inducción, que tiene relación con la estabilidad oxidativa del biodiesel y se determina por el método Rancimat. La RANP 14/12 establece el período de inducción mínimo de 6 h, que indica que el biocombustible será estable durante 6 meses de almacenamiento. En este trabajo se propone una metodología electroquímica para estudiar el comportamiento electroquímico de la oxidación de biodiesel, utilizando la técnica de voltametría cíclica. El biodiesel de soja metílico, sintetizado a partir de la ruta con catálisis básica homogénea, presentó período de inducción de 4,88 h y se utilizó en todos los experimentos de este trabajo. De las condiciones estudiadas para los ensayos de voltametría, el medio orgánico fue el elegido, usando ácido nítrico como electrólito de soporte. La metodología propuesta presenta una buena respuesta a la oxidación electroquímica del biodiesel, debido a la buena linealidad de aumento de la corriente de pico anódico con adición de muestra, con un coeficiente de correlación 0,996 para concentraciones de hasta 10,66 mg.mL-1 de biodiesel. Después de la concentración de 12,44 mg.mL-1, una pequeña desviación de la linealidad se observa, lo que podría atribuirse a la limitación del proceso catalítico en la superficie del electrodo de oro y a la posible formación de una película de poliacetonitrila. Los resultados obtenidos en el presente trabajo confirman la viabilidad del método propuesto para el estudio sobre la oxidación electroquímica de biodiesel.Palabras clave: Biodiesel. Estabilidad oxidativa. Voltametría cíclica

Network centrality: an introduction

Centrality is a key property of complex networks that influences the behavior of dynamical processes, like synchronization and epidemic spreading, and can bring important information about the organization of complex systems, like our brain and society. There are many metrics to quantify the node centrality in networks. Here, we review the main centrality measures and discuss their main features and limitations. The influence of network centrality on epidemic spreading and synchronization is also pointed out in this chapter. Moreover, we present the application of centrality measures to understand the function of complex systems, including biological and cortical networks. Finally, we discuss some perspectives and challenges to generalize centrality measures for multilayer and temporal networks.Comment: Book Chapter in "From nonlinear dynamics to complex systems: A Mathematical modeling approach" by Springe

Measurement of finite-frequency current statistics in a single-electron transistor

Electron transport in nano-scale structures is strongly influenced by the Coulomb interaction which gives rise to correlations in the stream of charges and leaves clear fingerprints in the fluctuations of the electrical current. A complete understanding of the underlying physical processes requires measurements of the electrical fluctuations on all time and frequency scales, but experiments have so far been restricted to fixed frequency ranges as broadband detection of current fluctuations is an inherently difficult experimental procedure. Here we demonstrate that the electrical fluctuations in a single electron transistor (SET) can be accurately measured on all relevant frequencies using a nearby quantum point contact for on-chip real-time detection of the current pulses in the SET. We have directly measured the frequency-dependent current statistics and hereby fully characterized the fundamental tunneling processes in the SET. Our experiment paves the way for future investigations of interaction and coherence induced correlation effects in quantum transport.Comment: 7 pages, 3 figures, published in Nature Communications (open access