Universality and criticality of a second-order granular solid-liquid-like phase transition

We experimentally study the critical properties of the non-equilibrium solid-liquid-like transition that takes place in vibrated granular matter. The critical dynamics is characterized by the coupling of the density field with the bond-orientational order parameter $Q_4$, which measures the degree of local crystallization. Two setups are compared, which present the transition at different critical accelerations as a a result of modifying the energy dissipation parameters. In both setups five independent critical exponents are measured, associated to different properties of $Q_4$: the correlation length, relaxation time, vanishing wavenumber limit (static susceptibility), the hydrodynamic regime of the pair correlation function, and the amplitude of the order parameter. The respective critical exponents agree in both setups and are given by $\nu_{\perp} = 1$, $\nu_{\parallel} = 2$, $\gamma = 1$, $\eta \approx 0.6 - 0.67$, and $\beta=1/2$, whereas the dynamical critical exponent is $z = \nu_{\parallel}/\nu_{\perp} = 2$. The agreement on five exponents is an exigent test for the universality of the transition. Thus, while dissipation is strictly necessary to form the crystal, the path the system undergoes towards the phase separation is part of a well defined universality class. In fact, the local order shows critical properties while density does not. Being the later conserved, the appropriate model that couples both is model C in the Hohenberg and Halperin classification. The measured exponents are in accord with the non-equilibrium extension to model C if we assume that $\alpha$, the exponent associated in equilibrium to the specific heat divergence but with no counterpart in this non-equilibrium experiment, vanishes.Comment: 14 pages, 13 figures, accepted in PR

Fluctuations and Criticality of a Granular Solid-Liquid-like Phase Transition

We present an experimental study of density and order fluctuations in the vicinity of the solid-liquid-like transition that occurs in a vibrated quasi-two-dimensional granular system. The two-dimensional projected static and dynamic correlation functions are studied. We show that density fluctuations, characterized through the structure factor, increase in size and intensity as the transition is approached, but they do not change significantly at the transition itself. The dense, metastable clusters, which present square symmetry, also increase their local order in the vicinity of the transition. This is characterized through the bond-orientational order parameter $Q_4$, which in Fourier space obeys an Ornstein-Zernike behavior. Depending on filling density and vertical height, the transition can be of first or second order type. In the latter case, the associated correlation length $\xi_4$, relaxation time $\tau_4$, zero $k$ limit of $Q_4$ fluctuations (static susceptibility), the pair correlation function of $Q_4$, and the amplitude of the order parameter obey critical power laws, with saturations due to finite size effects. Their respective critical exponents are $\nu_{\bot} = 1$, $\nu_{||} = 2$, $\gamma = 1$, $\eta=0.67$, and $\beta=1/2$, whereas the dynamical critical exponent $z = \nu_{||}/\nu_{\bot} = 2$. These results are consistent with model C of dynamical critical phenomena, valid for a non-conserved critical order parameter (bond-orientation order) coupled to a conserved field (density).Comment: 5 pages, 3 figures, to be published in Physical Review Letter

The early evolutionary history of neo-sex chromosomes in Neotropical grasshoppers, Boliviacris noroestensis (Orthoptera: Acrididae: Melanoplinae)

Neo-sex chromosomes are an important component of chromosome variation in Orthoptera, particularly South American Melanoplinae species, which have proven to be outstanding experimental model system to study the mechanism of sex chromosome evolution in this group of insects. In terms of their origin, most derived sex chromosome mechanisms involve a Robertsonian fusion (i.e. translocation) between the ancestral X chromosome and an autosome. In the grasshopper, Boliviacris noroestensis Ronderos & Cigliano (1990) (Orthoptera: Acrididae: Melanoplinae), our results point to a small degree of differentiation (conserved homology between the XR arm and the neo-Y) of the neo-XY chromosomes, which may be of recent evolutionary origin. However, a simple centric fusion model does not explain their origin, mainly because of the observed reduction in the fundamental number (FN) of arms. We propose two models which, we hope, clarify the genesis of B. noroestensis neo-sex chromosomes. Records of karyotype variation in related species due to multiple rearrangements support our models. We propose a possible adaptive advantage for neo-sex chromosome carriers, such changes perhaps representing the primary force that increases their frequency within natural populations compared with non-fused translocated forms, and occurring without apparent detriment to the microevolutionary forces that may also act, at least at the beginning of the evolutionary history of individuals bearing such neo-sex chromosomes.Fil: Castillo, Elio Rodrigo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Taffarel, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Marti, Dardo Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentin

Global Sources of Moisture: characterization and study of its variability

The current work is a climatological study and characterization of the global sources of moisture for continental precipitation based on a Lagrangian analysis technique. It consists of a synopsis of a series of articles published in specialist publications, thereby demonstrating the quality of the outcomes. The five key articles form the main structure of this research and it is these that address the crucial aspects of the atmospheric branch of the hydrological cycle, such as the characterization of the global sources of moisture, the interannual variability of the moisture transport, and the distribution of continental precipitation from oceanic moisture source regions. The study provides a robust identification of all major oceanic moisture sources as well as an assessment of their recent changes in amplitude, allowing three key scientific questions to be answered: (i) have the moisture source regions been stationary, or have they changed over the last three decades?, (ii) how do the changes in the intensity (more evaporation) and position of the sources affect the distribution of continental precipitation?, and (iii) what is the role of the main modes of climate variability such as ENSO, NAM and SAM in the variability of the moisture regions and the continental precipitation associated with each source? Moreover, by studying the potential influence on continental precipitation of the oceanic regions with higher evaporation minus precipitation rates in a future climate change scenario, this work is an analysis of the oceanic sources of continental precipitation linked to climate change. Finally, by using a catalogue to identify and characterize all the major moisture sources associated with the continental climatic regions based on two different regionalization schemes, this study provides a reliable and robust assessment of source-sink relationships in the atmospheric water cycle for regional climates, which is a requirement for understanding the major driving factor for extreme weather and climate events.Universidad de Costa Rica/[]/UCR/Costa RicaMinisterio de Ciencia e Innovación/[]/MICINN/EspañaFondo Europeo de Desarrollo Regional/[]/FEDER/EspañaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI

The skewness of scientific productivity

This paper exploits a unique 2003-2011 large dataset, indexed by Thomson & Reuters, consisting of 17.2 million disambiguated authors classified into 30 broad scientific fields, as well as the 48.2 million articles resulting from a multiplying strategy in which any article co-authored by two or more persons is wholly assigned as many times as necessary to each of them. The dataset is characterized by a large proportion of authors who have their oeuvre in several fields. We measure individual productivity in two ways that are uncorrelated: as the number of articles per person, and as the mean citation per article per person in the 2003-2011 period. We analyze the shape of the two types of individual productivity distributions in each field using size- and scale-independent indicators. For productivity inequality, we use the coefficient of variation. To assess the skewness of productivity distributions we use a robust index of skeweness, as well as the Characteristic Scores and Scales approach. For productivity inequality, we use the coefficient of variation. In each field, we study two samples: the entire population, and what we call “successful authors”, namely, the subset of scientists whose productivity is above their field average. The main result is that, in spite of wide differences in production and citation practices across fields, the shape of field productivity distributions are very similar across fields. The parallelism of the results for the population as a whole and for the subset of successful authors when productivity is measured as mean citation per article per person, reveals the fractal nature of the skewness of scientific productivity in this case. These results are essentially maintained when any article co-authored by two or more persons is fractionally assigned to each of them.Ruiz-Castillo also acknowledges financial help from the Spanish MEC through grant ECO2010-19596

Individual and Field Citation Distributions in 29 Broad Scientific Fields

Using a large unique dataset consisting of 35.1 million authors and 105.3 million articles published in the period 2000-2016, which are classified into 29 broad scientific fields, we search for regularities at the individual level for very productive authors with citation distributions of a certain size, and for the existence of a macro-micro relationship between the characteristics of a scientific field citation distribution and the characteristics of the individual citation distributions of the authors belonging to the field. Our main results are the following three. Firstly, although the skewness of individual citation distributions varies greatly within each field, their average skewness is of a similar order of magnitude in all fields. Secondly, as in the previous literature, field citation distributions are highly skewed and the degree of skewness is very similar across fields. Thirdly, the skewness of field citation distributions is essentially explained in terms of the average skewness of individual authors, as well as individuals’ differences in mean citation rates and the number of publications per author. These results have important conceptual and practical consequences: to understand the skewness of field citation distributions at any aggregate level we must simply explain the skewness of the individual citation distributions of their very productive authors.This is the second version of a paper with the same title published in this series in January 2018. J. Ruiz-Castillo acknowledges financial support from the Spanish MEC through grants ECO2014-55953-P and MDM 2014-0431, as well as grant MadEco-CM (S2015/HUM-3444) from the Comunidad Autónoma de Madrid. Research assistantship by Patricia Llopis, as well as conversations with Ricardo Mora, and especially Vincent Traag, are gratefully acknowledged. All remaining shortcomings are the authors’ sole responsibility

Synthesis of silicon- and germanium-rich phases at high-pressure conditions

The main focus of the present work was the Ge-rich part of the binary Ba – Ge system, in which by inspecting the behavior of the clathrate-I Ba8Ge43 under pressure, several new phases were found. The new phases in this system have the following compositions: BaGe3 (with two modifications), BaGe5, BaGe5.5 and BaGe6, therefore they are quite close in composition range: 75% - ~85% at. Ge. Concerning the conditions required for the synthesis of each phase, several combinations of temperature and pressure were employed in order to find a stability range. It was possible to establish such a formation range for all phases. In some cases two phases were found for a given conditions and in many other cases three or more phases were found to coexist. Thus, the stability range of pressure and temperature for single phase formation turned out to be very narrow. By inspecting of some structural features, for instance the interatomic distances, it is found that the average of the Ge – Ge distances change in line with the composition, i.e. the shorter contacts belong to BaGe6 while the longer distances are present in BaGe3 (both modification). An opposite trend is observed for the calculated density of each phase (neglecting the tI32 form of BaGe3): the lower density is found for BaGe3 and the denser compound is found to be BaGe6. Of course this is not coincidence, since due to the Ge content, BaGe6 has the largest molar mass. Similarly, by examining the density as a function of the interatomic distance. In such case, the denser compound is characterized by shorter Ge – Ge contacts, while the less dense phase holds the longest Ge – Ge contacts. This is in agreement with the building motifs within each crystal structure: columns in BaGe3 (open framework) passing through layers in BaGe5, ending in a three-dimensional network (closed framework) in BaGe6

Análisis de la figura de la filiación en la Legislación Nicaragüense

El trabajo de investigación se realizó con la expectativa de tener amplio conocimiento sobre diversos temas del derecho de familia, por lo tanto se obtuvo información en materia de filiación. El objetivo radica en analizar desde la óptica legal la f iliación, la relación entre el Padre, la Madre y los H ijos, las obligaciones y los derechos que genera el vínculo filial. El estudio de las generalidades sobre la figura de la filiación desde el punto de vista de la doctrina ,así como identificación del marco normativo que regula la figura de la filiación,además de la comparación de la legislación sobre la filiación de Nicaragua con la legislación de El Salvador y Costa Rica son otros objetivos que contribuyeron a la obtención de los resultados. La investigación es de carácter descriptivo expli cativo y la técnica que se utilizó fue mediante consulta bibliográfica, combinada con entrevistas a profesionales del Derecho. El tema de filiación es muy importante ya que se refiere a la procedencia de los hijos respecto a los padres. Es un derecho que toda persona tiene des de el momento de su procreación. Es la relación jurídica que se establece entre las personas a quienes el Derecho coloca en la condición de Padre,Madre y sitúa a los hijos, en su realidad biológica la cual es recogida por el ordenamiento jurídico, proporcionándoles derechos y obligaciones entre sí. Análisis de la Figura de la Filiación en la Legislación Nicaragüense La filiación, en sentido biológico se refiere a la relación entre el generado y los venerantes. En sentido jurídico,filiación es el vínculo que une al progenitor con el hijo y es reconocido por el Derecho.No se trata de puro origen genético, sino de aquella relación que basada en éste origen, pero no de modo necesario, reconoce el derecho que existe entre padres e hijos y en virtud de la cual se establecen deberes y derechos a cargo de unos y otros. Aquí, frente a la realidad biológica, hay hijos que no tienen Padre, o Madre, o ninguno de los dos; como los que tienen un Padre o unos Padres de quienes no proceden biológicamente: (los adoptivos).El presente estudio muestra que aparte de los derechos que se crean a través de la filiación, no solo está el derecho a ser reconocido como hijo o hija,también sirve para efectos sucesorios, la patria potestad, también se toma en cuenta para establecer prohibiciones en el nombramiento de funcionarios públicos que éstos tengan parentesco. En el estudio se hizo uso del Derecho comparado entre los códigos de familia de los países de Costa Rica, El Salvador y el proyecto de código de familia de Nicaragua los cuales tienen similitudes en la protección de los derechos de los niños y niñas y se utilizan formas muy parecidas de determinación de la filiación,La diferencia radica en que estos países cuentan desde hace mucho tiempo, con un código de familia que regula todo lo relacionado en materia de filiación. Mientras que a Nicaragua le hace mucha falta dicho código debido a que todas las leyes en materia de familia están dispersas y es necesario disponer en un mismo libro todo lo relacionado al tema

Draft Whole-Genome Sequences of Xylella fastidiosa subsp. fastidiosa Strains TPD3 and TPD4, Isolated from Grapevines in Hou-li, Taiwan.

We report the draft assemblies of TPD3 and TPD4, two Xylella fastidiosa subsp. fastidiosa isolates infecting grapevines in Hou-li, Taiwan. TPD3 and TPD4 showed similar characteristics regarding genome size (2,483,503 bp and 2,491,539 bp, respectively), GC content (51.49% and 51.47%, respectively), and number of protein-coding sequences (2,394 and 2,413, respectively)