2,552 research outputs found

    Arrow of time across five centuries of classical music

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    The concept of time series irreversibility—the degree by which the statistics of signals are not invariant under time reversal—naturally appears in nonequilibrium physics in stationary systems which operate away from equilibrium and produce entropy. This concept has not been explored to date in the realm of musical scores as these are typically short sequences whose time reversibility estimation could suffer from strong finite size effects which preclude interpretability. Here we show that the so-called horizontal visibility graph method—which recently was shown to quantify such statistical property even in nonstationary signals—is a method that can estimate time reversibility of short symbolic sequences, thus unlocking the possibility of exploring such properties in the context of musical compositions. Accordingly, we analyze over 8000 musical pieces ranging from the Renaissance to the early Modern period and show that, indeed, most of them display clear signatures of time irreversibility. Since by construction stochastic processes with a linear correlation structure (such as 1 / f noise) are time reversible, we conclude that musical compositions have a considerably richer structure, that goes beyond the traditional properties retrieved by the power spectrum or similar approaches. We also show that musical compositions display strong signs of nonlinear correlations, that nonlinearity is correlated to irreversibility, and that these are also related to asymmetries in the abundance of musical intervals, which we associate to the narrative underpinning a musical composition. These findings provide tools for the study of musical periods and composers, as well as criteria related to music appreciation and cognition

    Unusual formations of the free electromagnetic field in vacuum

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    It is shown that there are exact solutions of the free Maxwell equations (FME) in vacuum allowing an existence of stable spherical formations of the free magnetic field and ring-like formations of the free electric field. It is detected that a form of these spheres and rings does not change with time in vacuum. It is shown that these convergent solutions are the result of an interference of some divergent solutions of FME. One can surmise that these electromagnetic formations correspond to Kapitsa's hypothesis about interference origin and a structure of fireball.Comment: Revtex-file, without figures. To get lournal-pdf-copy with figures contact with [email protected]

    Assembly of Matted Panels with Guadua Cane (Angustifolia Kunth), for Construction of Houses in Manabi Province

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    In some regions of Ecuador, mainly in the rural areas, the bamboo cane (Angustifolia Kunth), is presented as a renewable natural resource par excellence, which has ecological importance, the wood obtained from this plant is used since very ancient times in the construction of Housing, its technology has not changed in several years. Its industrialization is restricted, due to different factors, mainly because the natural characteristics of the material are unknown, such as age, moisture content, soil nutrients, and treatment after cutting, among others. Knowing these elements can be implemented technologies for the cutting and sterilization of the wood obtained from these plantations and develops a national technology for the construction of housing for social use, thereby achieving an impact on society by having more comfortable, safe and economic facilities

    A Comprehensive Analysis of Gene Expression and Genomic Alterations in a Newly Formed Autotetraploid of \u3cem\u3ePaspalum Notatum\u3c/em\u3e

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    The proportion of angiosperms that have experienced one or more episodes of chromosome doubling is estimated to be of the order of 50-70%. This prominence of polyploidy probably implies some adaptive significance. The emergence of novel phenotypes could allow polyploids to enter new niches or enhance their chances of being selected for use in agriculture. Although the causes of novel variation in polyploids are not well understood, they could involve changes in gene expression through dosage-regulation, altered regulatory interactions and rapid genetic/epigenetic changes. The objective of this work was to carry out an extensive transcript profiling and genome analysis of a diploid genotype of the pasture grass Paspalum notatum and its tetraploid derivative obtained after colchicine treatment

    Comparative pan-genome analysis of Piscirickettsia salmonis reveals genomic divergences within genogroups

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    Indexación: Scopus.Piscirickettsia salmonis is the etiological agent of salmonid rickettsial septicemia, a disease that seriously affects the salmonid industry. Despite efforts to genomically characterize P. salmonis, functional information on the life cycle, pathogenesis mechanisms, diagnosis, treatment, and control of this fish pathogen remain lacking. To address this knowledge gap, the present study conducted an in silico pan-genome analysis of 19 P. salmonis strains from distinct geographic locations and genogroups. Results revealed an expected open pan-genome of 3,463 genes and a core-genome of 1,732 genes. Two marked genogroups were identified, as confirmed by phylogenetic and phylogenomic relationships to the LF-89 and EM-90 reference strains, as well as by assessments of genomic structures. Different structural configurations were found for the six identified copies of the ribosomal operon in the P. salmonis genome, indicating translocation throughout the genetic material. Chromosomal divergences in genomic localization and quantity of genetic cassettes were also found for the Dot/Icm type IVB secretion system. To determine divergences between core-genomes, additional pan-genome descriptions were compiled for the so-termed LF and EM genogroups. Open pan-genomes composed of 2,924 and 2,778 genes and core-genomes composed of 2,170 and 2,228 genes were respectively found for the LF and EM genogroups. The core-genomes were functionally annotated using the Gene Ontology, KEGG, and Virulence Factor databases, revealing the presence of several shared groups of genes related to basic function of intracellular survival and bacterial pathogenesis. Additionally, the specific pan-genomes for the LF and EM genogroups were defined, resulting in the identification of 148 and 273 exclusive proteins, respectively. Notably, specific virulence factors linked to adherence, colonization, invasion factors, and endotoxins were established. The obtained data suggest that these genes could be directly associated with inter-genogroup differences in pathogenesis and host-pathogen interactions, information that could be useful in designing novel strategies for diagnosing and controlling P. salmonis infection. © 2017 Nourdin-Galindo, Sánchez, Molina, Espinoza-Rojas, Oliver, Ruiz, Vargas-Chacoff, Cárcamo, Figueroa, Mancilla, Maracaja-Coutinho and Yañez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00459/ful

    Seleção de porta-enxertos para maracujazeiro-amarelo nas condições da depressão cuiabana.

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    O presente trabalho foi realizado na Fazenda Experimental da Fundação Universidade Federal de Mato Grosso, com o objetivo de selecionar porta-enxertos, que apresentava maior vigor vegetativo para o maracujazeiros-amarelos, nas condições da Depressão Cuiabana. O delineamento experimental utilizado foi blocos ao acaso, sendo as épocas de avaliação consideradas como blocos (60, 75, 90, 105 e 120 dias), os tratamentos foram os porta-enxertos (seleção FB200 e a espécie Passiflora nítida), com 3 repetições. As variáveis estudadas foram o diâmetro do colo, diâmetro do tronco cerca de 1 cm acima da região enxertada, altura do colo da planta até o enxerto, altura a partir do enxerto, altura total, número de entrenós até a região enxertada, número de entrenós a partir da região enxertada e número de folhas. Os dados foram tabulados utilizando-se o pacote Statistical Package for the Social Science (SPSS) versão 11.0 e submetidos à analise estatística descritiva. Posteriormente, as variáveis foram submetidas à análise de variância multivariada com dois fatores (Manova two-way). O uso da análise de MANOVA, possibilitou observar que os porta-enxertos, o tempo e as interação entre eles tiveram grande importância na avaliação do desenvolvimento vegetativo do maracujazeiro-amarelo. A melhor resposta quanto ao desenvolvimento vegetativo foi induzido pelo porta-enxerto. O porta-enxerto ?FB200? apresentou resultados mais favoráveis quanto ao vigor de suas mudas

    Influence of Silver Nitrate on Somatic Embryogenesis Induction in Arabica Coffee (Coffea arabica L.).

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    Plant somatic embryogenesis (SE) has been defined as the formation of embryos from a single or group of haploid or somatic cells [1, 2]. Low frequency (LFSE) and high frequency somatic embryogenesis (HFSE) have been described. In the first type, somatic embryos are induced directly from pro-embryogenic cells of explants, while in the second, they originate from embryogenic callus [1]. It has been suggested that in LFSE the origin of somatic embryos is unicellular, whereas in HFSE has been described as unicellular or multicellular [3]. SE is a powerful biotechnological tool used to propagate elite plants or to conserve important genotypes [4]. Moreover, SE offers an efficient in vitro regeneration approach as a fundamental step in plant genetic improvement for studying basic aspects of ontogenesis of somatic embryos [5]. In Coffea spp., the first studies of SE have been reported at the beginning of 1970 [6]. Since then, a large quantity of LFSE and HFSE protocols have been optimized demonstrating that coffee is not a recalcitrant species for SE [4]. In the LFSE the somatic embryos are obtained faster (approximately 70 days) using only one medium meanwhile in HFSE several media are used and somatic embryo formation takes 9-10 months [4]. Although, in LFSE small number of somatic embryos are obtained (around 10 per explant) compared to hundreds of somatic embryos obtained per gram of embryogenic calli [4], the unicellular origin of somatic embryos in LFSE represents an advantage for the chemical and physical mutagenesis, genetic transformation and genetic editing, since prevents or reduces the appearance of chimeras [7]. In C. arabica and C. canephora many factors (such as genotype, explant type, the physiological state, age and growth conditions of the donor plants, the season of collection, nutrient composition of the medium, the volume of dissolved CO2 or O2 in the culture flask, and plant growth regulators) that affect LFSE induction have been studied [3, 8, 9, 10, 11, 12, 13]. However, few studies reported the effect of silver nitrate on LFSE using leaf explants of C. arabica L. and to the best of our knowledge it has not been analyzed using Caturra and Catuaí, which are two economic important producer cultivars in Costa Rica. Since SE is genotype dependent, the culture medium need to be modified for the different genotypes [7].Therefore, the objective of this study was to determine the influence of the benzyladenine (BAP), indole-3-acetic acid (IAA), and silver nitrate (AgNO3) on low frequency somatic embryogenesis using leaf explants of Coffea arabica L. cultivars Caturra and Catuaí

    The Mass-Radius Relationship for Very Low Mass Stars: Four New Discoveries from the HATSouth Survey

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    We report the discovery of four transiting F-M binary systems with companions between 0.1-0.2 Msun in mass by the HATSouth survey. These systems have been characterised via a global analysis of the HATSouth discovery data, combined with high-resolution radial velocities and accurate transit photometry observations. We determined the masses and radii of the component stars using a combination of two methods: isochrone fitting of spectroscopic primary star parameters, and equating spectroscopic primary star rotation velocity with spin-orbit synchronisation. These new very low mass companions are HATS550-016B (0.110 -0.006/+0.005 Msun, 0.147 -0.004/+0.003 Rsun), HATS551-019B (0.17 -0.01/+0.01 Msun, 0.18 -0.01/+0.01 Rsun), HATS551-021B (0.132 -0.005/+0.014 Msun, 0.154 -0.008/+0.006 Rsun), HATS553-001B (0.20 -0.02/+0.01 Msun, 0.22 -0.01/+0.01 Rsun). We examine our sample in the context of the radius anomaly for fully-convective low mass stars. Combining our sample with the 13 other well-studied very low mass stars, we find a tentative 5% systematic deviation between the measured radii and theoretical isochrone models.Comment: 17 pages, 8 figures, accepted for publication in MNRA
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