Additive Noise Induces Front Propagation

The propagation of a front connecting a stable homogeneous state with a stable periodic state in the presence of additive noise is studied. The mean velocity was computed both numerically and analitically. The numerics are in good agreement with the analitical prediction.Comment: 4 pages, 5 figure

NMR Experiments on a Three-Dimensional Vibrofluidized Granular Medium

A three-dimensional granular system fluidized by vertical container vibrations was studied using pulsed field gradient (PFG) NMR coupled with one-dimensional magnetic resonance imaging (MRI). The system consisted of mustard seeds vibrated vertically at 50 Hz, and the number of layers N_ell <= 4 was sufficiently low to achieve a nearly time-independent granular fluid. Using NMR, the vertical profiles of density and granular temperature were directly measured, along with the distributions of vertical and horizontal grain velocities. The velocity distributions showed modest deviations from Maxwell-Boltzmann statistics, except for the vertical velocity distribution near the sample bottom which was highly skewed and non-Gaussian. Data taken for three values of N_ell and two dimensionless accelerations Gamma=15,18 were fit to a hydrodynamic theory, which successfully models the density and temperature profiles including a temperature inversion near the free upper surface.Comment: 14 pages, 15 figure

El modelo sistémico de aprendizaje y enseñanza, como apoyo en la inserción laboral

The main objective of the research was to find out how the systemic process influences with the teaching and learning approach, in the labor inclusion of graduates of the Faculty of Law of the National University Hermilio Valdizán. To achieve this, the study was developed based on a descriptive explanatory type, under a non-experimental, correlational and cross-sectional design, for which we worked with a population of 121 graduates and the sample consisted of 37 graduates from the years 2016 and 2017, being of the non-probabilistic type, which were constructed two questionnaires, a questionnaire to measure the systematic teaching-learning process variable, another questionnaire to measure the job placement opportunity variable, all to qualify the level of influence. Sperman's Ro test was applied to evaluate the hypothesis. As a result, our results confirmed the study hypothesis, showing that the systemic teaching-learning process shows a significant relationship with job placement and that there is a positive influence between both variables. Reaching the conclusion that exercising a systemic process in teaching and learning generates opportunity in labor inclusion.La investigación tuvo como objetivo principal buscar cómo influye el proceso sistémico con el enfoque de enseñanza y aprendizaje, en la inclusión laboral de los egresados de la Facultad de Derecho de la Universidad Nacional Hermilio Valdizán. Para lograrlo, se desarrolló el estudio en base a tipo descriptivo explicativo, bajo un diseño no experimental, correlacional &nbsp;y de tipo transversal, para lo cual se trabajó con una población de 121 egresados y la muestra estuvo constituida por 37 egresados de los años 2016 y 2017, siendo del tipo no probabilístico, los cuales se construyeron dos cuestionarios, un cuestionario para medir la variable proceso sistemático de enseñanza-aprendizaje, otro cuestionario para medir la variable oportunidad de inserción laboral, todo ello para calificar el nivel de influencia. Para evaluar la hipótesis se aplicó la prueba Ro de Sperman. A raíz de ello nuestros resultados confirmaron la hipótesis de estudio, demostrando que el proceso sistémico de enseñanza-aprendizaje muestra una relación significativa con la inserción laboral y que existe influencia positiva entre ambas variables. Llegando a la conclusión que ejercer un proceso sistémico en la enseñanza y aprendizaje genera oportunidad en la inclusión laboral

Glassy systems under time-dependent driving forces: application to slow granular rheology

We study the dynamics of a glassy model with infinite range interactions externally driven by an oscillatory force. We find a well-defined transition in the (Temperature-Amplitude-Frequency) phase diagram between (i) a `glassy' state characterized by the slow relaxation of one-time quantities, aging in two-time quantities and a modification of the equilibrium fluctuation-dissipation relation; and (ii) a `liquid' state with a finite relaxation time. In the glassy phase, the degrees of freedom governing the slow relaxation are thermalized to an effective temperature. Using Monte-Carlo simulations, we investigate the effect of trapping regions in phase space on the driven dynamics. We find that it alternates between periods of rapid motion and periods of trapping. These results confirm the strong analogies between the slow granular rheology and the dynamics of glasses. They also provide a theoretical underpinning to earlier attempts to present a thermodynamic description of moderately driven granular materials.Comment: Version accepted for publication - Physical Review

Cenozoic Antarctic DiatomWare/BugCam: An aid for research and teaching

Cenozoic Antarctic DiatomWare/BugCam© is an interactive, icon-driven digital-imagedatabase/software package that displays over 500 illustrated Cenozoic Antarctic diatom taxa along with original descriptions (including over 100 generic and 20 family-group descriptions). This digital catalog is designed primarily for use by micropaleontologists working in the field (at sea or on the Antarctic continent) where hard-copy literature resources are limited. This new package will also be useful for classroom/lab teaching as well as for any paleontologists making or refining taxonomic identifications at the microscope. The database (Cenozoic Antarctic DiatomWare) is displayed via a custom software program (BugCam) written in Visual Basic for use on PCs running Windows 95 or later operating systems. BugCam is a flexible image display program that utilizes an intuitive thumbnail “tree” structure for navigation through the database. The data are stored on Micrsosoft EXCEL spread sheets, hence no separate relational database program is necessary to run the package

CALIFA : a diameter-selected sample for an integral field spectroscopy galaxy survey

JMA acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild).We describe and discuss the selection procedure and statistical properties of the galaxy sample used by the Calar Alto Legacy Integral Field Area (CALIFA) survey, a public legacy survey of 600 galaxies using integral field spectroscopy. The CALIFA "mother sample" was selected from the Sloan Digital Sky Survey (SDSS) DR7 photometric catalogue to include all galaxies with an r-band isophotal major axis between 45 '' and 79 : 2 '' and with a redshift 0 : 005 M-r > -23 : 1 and over a stellar mass range between 10(9.7) and 10(11.4) M-circle dot. In particular, within these ranges, the diameter selection does not lead to any significant bias against - or in favour of - intrinsically large or small galaxies. Only below luminosities of M-r = -19 (or stellar masses <10(9.7) M-circle dot) is there a prevalence of galaxies with larger isophotal sizes, especially of nearly edge-on late-type galaxies, but such galaxies form <10% of the full sample. We estimate volume-corrected distribution functions in luminosities and sizes and show that these are statistically fully compatible with estimates from the full SDSS when accounting for large-scale structure. For full characterization of the sample, we also present a number of value-added quantities determined for the galaxies in the CALIFA sample. These include consistent multi-band photometry based on growth curve analyses; stellar masses; distances and quantities derived from these; morphological classifications; and an overview of available multi-wavelength photometric measurements. We also explore different ways of characterizing the environments of CALIFA galaxies, finding that the sample covers environmental conditions from the field to genuine clusters. We finally consider the expected incidence of active galactic nuclei among CALIFA galaxies given the existing pre-CALIFA data, finding that the final observed CALIFA sample will contain approximately 30 Sey2 galaxies.Peer reviewe

The NANOGrav Nine-year Data Set: Excess Noise in Millisecond Pulsar Arrival Times

Gravitational wave (GW) astronomy using a pulsar timing array requires high-quality millisecond pulsars (MSPs), correctable interstellar propagation delays, and high-precision measurements of pulse times of arrival. Here we identify noise in timing residuals that exceeds that predicted for arrival time estimation for MSPs observed by the North American Nanohertz Observatory for Gravitational Waves. We characterize the excess noise using variance and structure function analyses. We find that 26 out of 37 pulsars show inconsistencies with a white-noise-only model based on the short timescale analysis of each pulsar, and we demonstrate that the excess noise has a red power spectrum for 15 pulsars. We also decompose the excess noise into chromatic (radio-frequency-dependent) and achromatic components. Associating the achromatic red-noise component with spin noise and including additional power-spectrum-based estimates from the literature, we estimate a scaling law in terms of spin parameters (frequency and frequency derivative) and data-span length and compare it to the scaling law of Shannon & Cordes. We briefly discuss our results in terms of detection of GWs at nanohertz frequencies

The Cyprinodon variegatus genome reveals gene expression changes underlying differences in skull morphology among closely related species

Genes in durophage intersection set at 15 dpf. This is a comma separated table of the genes in the 15 dpf durophage intersection set. Given are edgeR results for each pairwise comparison. Columns indicating whether a gene is included in the intersection set at a threshold of 1.5 or 2 fold are provided. (CSV 13 kb