Adaptive, locally-linear models of complex dynamics

The dynamics of complex systems generally include high-dimensional, non-stationary and non-linear behavior, all of which pose fundamental challenges to quantitative understanding. To address these difficulties we detail a new approach based on local linear models within windows determined adaptively from the data. While the dynamics within each window are simple, consisting of exponential decay, growth and oscillations, the collection of local parameters across all windows provides a principled characterization of the full time series. To explore the resulting model space, we develop a novel likelihood-based hierarchical clustering and we examine the eigenvalues of the linear dynamics. We demonstrate our analysis with the Lorenz system undergoing stable spiral dynamics and in the standard chaotic regime. Applied to the posture dynamics of the nematode $C. elegans$ our approach identifies fine-grained behavioral states and model dynamics which fluctuate close to an instability boundary, and we detail a bifurcation in a transition from forward to backward crawling. Finally, we analyze whole-brain imaging in $C. elegans$ and show that the stability of global brain states changes with oxygen concentration.Comment: 25 pages, 16 figure

Complex Grid Computing

This article investigates the performance of grid computing systems whose interconnections are given by random and scale-free complex network models. Regular networks, which are common in parallel computing architectures, are also used as a standard for comparison. The processing load is assigned to the processing nodes on demand, and the efficiency of the overall computing is quantified in terms of the respective speed-ups. It is found that random networks allow higher computing efficiency than their scale-free counterparts as a consequence of the smaller number of isolated clusters implied by the former model. At the same time, for fixed cluster sizes, the scale free model tend to provide slightly better efficiency. Two modifications of the random and scale free paradigms, where new connections tend to favor more recently added nodes, are proposed and shown to be more effective for grid computing than the standard models. A well-defined correlation is observed between the topological properties of the network and their respective computing efficiency.Comment: 5 pages, 2 figure

Gramsci, Leitor de Marx

No artigo sugerida uma aproxima o entre as proposi es contidas nas teses do jovem Karl Marx 1818-1883 e do pensador italiano Antonio Gramsci 1891-1937 em per odo de sua vida anterior ao c rcere fascista ou seja antes de 1926 Contrariamente a qualquer arroubo extempor neo de minimizar o valor e a originalidade das obras de maturidade de Gramsci este trabalho pretende assinalar a consist ncia te rica e a pr tica pol tica amadurecida em um crisol de lutas ambiente no qual foram lavrados os escritos anteriores aos Quaderni del carcere obra considerada como uma atualiza o cabal das estrat gias do marxismo para a o na contemporaneidad

Emergent complexity in slowly driven stochastic processes

We consider the distribution of first passage time events in the presence of non-ergodic modes that drive otherwise ergodic dynamics on a potential landscape. We find that in the limit of slow and large enough fluctuations the distribution of first passage time events, $f(t)$, exhibits heavy tails dominated by a power law with exponent $f(t)\sim t^{-2}$, and corrections that depend on the strength and the nature of fluctuations. We support our theoretical findings through direct numerical simulations in illustrative examples.Comment: 13 pages, 7 figure

Biotechnology and vaccines

Biotechnology has demonstrated its importance for health development, especially in the discovery of new drugs and production of vaccines. On account of the occurrence of many diseases that have killed millions of people in the world, vaccines were developed to control infections and prevent diseases caused by viruses, bacteria, protozoans and fungi, and even eradicate them, as is the case of smallpox. Vaccines can be of first, second and third generation. Currently, vaccine manufacturing can be directed to the use of DNA containing the gene that encodes an antigenic protein. The present work is a literature review, with the objective to present the first-, second- and third-generation vaccines, as well as to make an analysis of the use of these vaccines in Brazil

Herdabilidade estimada por diferentes métodos em quatro gerações de progênies de um cruzamento de guandu

The objective of this work was to compare different methods to estimate heritability in 30 pigeon pea families from the F3, F4, F5, and F6 generations, for nine variables. The experimental design was a randomized complete block with three replicates and 20 plants per plot. Broad-sense heritability was estimated by the analysis of variance (ANOVA) [h2b-E(MS)], restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) (h2b-REML), parent-offspring regression (h2PO), and standard deviation unit (h2UP). The h2b-E(MS) and h2b-REML estimates were similar for seven of the analyzed variables. For a higher genetic control and easier selection, values of h2b-E(MS) and h2b-REML >0.70 were estimated for two variables in four generations, two variables in three generations, three variables in two generations, and one variable in one generation. Values of h2UP and h2PO >0.70 were obtained for four and five variables, respectively. The estimates via regression or parent-offspring correlation showed some values outside the expected range of 0 to 1. The ANOVA [h2b-E(MS)] and REML/BLUP [h2b-REML] methods are the best to estimate pigeon pea heritability.O objetivo deste trabalho foi comparar diferentes métodos para estimar a herdabilidade em 30 linhagens de guandu das gerações F3, F4, F5 e F6,  para nove variáveis. O delineamento experimental foi em blocos ao acaso, com três repetições e 20 plantas por parcela. Estimou-se a herdabilidade no sentido amplo por meio de análise de variância (ANOVA) [h2b-E(MS)], máxima verossimilhança restrita/melhor predição linear não viciada (REML/BLUP) (h2b-REML), regressão pai-filho (h2PO) e unidade do desvio-padrão (h2UP). As estimativas de h2b-E(MS) e h2b-REML foram de magnitude próxima para sete das variáveis analisadas. Para maior controle genético e facilidade na seleção, valores de h2b-E(MS) e h2b-REML >0,70 foram estimados para duas variáveis em quatro gerações, duas variáveis em três gerações, três variáveis em duas gerações e uma variável em uma geração. Valores de h2UP e h2PO >0,70 foram obtidos para quatro e cinco variáveis, respectivamente. As estimativas via regressão ou correlação pai-filho mostraram alguns valores fora da variação esperada de 0 a 1. Os métodos ANOVA [h2b-E(MS)] e REML/BLUP [h2b-REML] são os melhores para estimar a herdabilidade em guandu

A trajetória masculina no mundo da dança na sociedade moderna brasileira

Este artigo visa percorrer, através de incursao documental sobre o mundo da dança na sociedade moderna e sobretudo em sua prática na cidade do Rio de Janeiro. O objeto do trabalho é a presença do homem nos vários contextos em havia a prática da dança, seja nos espaços da alta sociedade, nos saloes de frequência predominante masculina ou nas ruas na forma do lazer e da sátira, como é o caso do carnaval. Nesse estudo coube nossas reflexoes pessoais, considerando nossa experiência no campo da dança e as valorosas contribuiçoes dos jornais de época, quando nos concentramos no cotidiano do século XIX e início do Século XX. As maiores contribuiçoes partem das crônicas do Jornalista Delso Renault, que compilou inúmeras reportagens de época onde a presença do homem no mundo da dança nao reflete o atual momento em que a predominância da presença feminina nos saloes e nos palcos nos revela uma imagem de que o homem abandonou, se afastou ou foi excluído por algum motivo no cenário que envolve a dança. Nesse sentido o trabalho no levou analisar a trajetória do homem na dança e como esse gênero se fez e se faz ausente ou presente em determinado espaços sociais. Além de Delso Renault, fizemos incursos pela literatura discutindo o cotidiano e sua transformaçao moral, religiosa, artística e sócio-econômica, uma vez que a dança deixa de ser um aspecto meramente lúdico, de aproximaçao corporal de homem e mulher e passa, em boa parte de sua prática, por um ato profissiona

Modeling the ballistic-to-diffusive transition in nematode motility reveals variation in exploratory behavior across species

A quantitative understanding of organism-level behavior requires predictive models that can capture the richness of behavioral phenotypes, yet are simple enough to connect with underlying mechanistic processes. Here we investigate the motile behavior of nematodes at the level of their translational motion on surfaces driven by undulatory propulsion. We broadly sample the nematode behavioral repertoire by measuring motile trajectories of the canonical lab strain $C. elegans$ N2 as well as wild strains and distant species. We focus on trajectory dynamics over timescales spanning the transition from ballistic (straight) to diffusive (random) movement and find that salient features of the motility statistics are captured by a random walk model with independent dynamics in the speed, bearing and reversal events. We show that the model parameters vary among species in a correlated, low-dimensional manner suggestive of a common mode of behavioral control and a trade-off between exploration and exploitation. The distribution of phenotypes along this primary mode of variation reveals that not only the mean but also the variance varies considerably across strains, suggesting that these nematode lineages employ contrasting ``bet-hedging'' strategies for foraging.Comment: 46 pages, 18 figures, 6 table

Associação entre potássio sérico na admissão hospitalar e letalidade da leptospirose em homens

Severe leptospirosis affects predominantly males and presents a high susceptibility to hypokalemic acute renal failure. As hypokalemia and hyperkalemia induce severe complications, it is important to evaluate if the initial serum potassium is an independent risk factor for death in leptospirosis. The medical records of 1016 patients hospitalized with the diagnosis of leptospirosis were reviewed. The analysis was restricted to 442, according to the following criteria: male, 18 years or older, information about death or hospital discharge and recorded values of serum potassium, serum creatinine and duration of symptoms at admission. Potassium values lower than 3.5 mEq/L (hypoK), 3.5-5 mEq/L (normoK) and above 5 mEq/L (hyperK) were detected in 180, 245 and 17 patients, respectively. The death rate increased with serum potassium: 11.1% in the hypoK, 14.7% in the normoK and 47.1% in the hyperK group (p = 0.002). In a logistic regression model (normoK as referent), including age, creatinine and duration of symptoms, hypoK was not associated with increased death rate (odds ratio (OR) = 0.80; p >; 0.1). On the other hand, hyperK showed a significant association with increased risk of death (OR = 3.95, p = 0.021). In conclusion, in this sample of men with leptospirosis initial serum potassium was positively and independently correlated with the risk of in-hospital death.Leptospirose grave afeta predominantemente os homens e apresenta alta susceptibilidade para insuficiência renal aguda com hipocalemia. Como hipocalemia e hipercalemia induzem complicações graves, é importante avaliar se o potássio sérico é um independente fator de risco de morte na leptospirose. Foram revistos os prontuários de 1016 pacientes internados com o diagnóstico de leptospirose. A análise foi restrita a 442, obedecendo os seguintes critérios: sexo masculino, idade igual ou superior a 18 anos, informação sobre morte ou alta hospitalar e registro dos valores do potássio sérico, da creatinina sérica e da duração dos sintomas. Valores de potássio menor do que 3,5 mEq/l (hipoK), 3,5-5 mEq/L (normoK) e superior a 5 mEq/L (hiperK) foram detectados em 180, 245 e 17 pacientes, respectivamente. A mortalidade aumentou com a elevação do potássio: 11,1% no grupo hipoK, 14,7% no normoK e 47,1% no hiperK (p = 0,002). Em um modelo de regressão logística (normoK como referência), incluindo idade, creatinina e duração de sintomas, hipoK não se associou com aumento da mortalidade (odds ratio (OR) = 0,72; p >; 0,1). Contrariamente, hiperK foi significantemente associado com risco aumentado de morte (OR = 3,95; p = 0,021). Em conclusão, nesta amostra de homens com leptospirose o potássio sérico inicial foi positivamente e independentemente correlacionado com risco de morte hospitalar