Velocity and Distribution of Primordial Neutrinos

The Cosmic Neutrinos Background (\textbf{CNB}) are Primordial Neutrinos decoupled when the Universe was very young. Its detection is complicated, especially if we take into account neutrino mass and a possible breaking of Lorentz Invariance at high energy, but has a fundamental relevance to study the Big-Bang. In this paper, we will see that a Lorentz Violation does not produce important modification, but the mass does. We will show how the neutrinos current velocity, with respect to comobile system to Universe expansion, is of the order of 1065 $[\frac{km}{s}]$, much less than light velocity. Besides, we will see that the neutrinos distribution is complex due to Planetary motion. This prediction differs totally from the usual massless case, where we would get a correction similar to the Dipolar Moment of the \textbf{CMB}.Comment: 16 pages, latex, 7 figure

Pressure-induced structural, electronic, and magnetic effects in BiFeO3

We present a first-principles study of multiferroic BiFeO3 at high pressures. Our work reveals the main structural (change in Bi's coordination and loss of ferroelectricity), electronic (spin crossover and metallization), and magnetic (loss of order) effects favored by compression and how they are connected. Our results are consistent with the striking manifold transition observed experimentally by Gavriliuk et al. [Phys. Rev. B 77, 155112 (2008)] and provide an explanation for it.Comment: 4 pages with 4 figures embedded. More information at http://www.icmab.es/dmmis/leem/jorg

First-principles predictions of low-energy phases of multiferroic BiFeO3

We used first-principles methods to perform a systematic search for potentially-stable phases of multiferroic BiFeO3. We considered a simulation cell compatible with the atomic distortions that are most common among perovskite oxides, and found a large number of local minima of the energy within 100 meV/f.u. of the ferroelectric ground state. We discuss the variety of low-symmetry structures discovered, as well as the implications of these findings as regards current experimental (e.g., on thin films displaying {\em super-tetragonal} phases) and theoretical (on models for BiFeO3's structural phase transitions) work on this compound.Comment: 14 pages, 9 figures, accepted in PRB (contains small changes in the text with respect to the first version

Global effects of US uncertainty: real and financial shocks on real and financial markets

We estimate the effects of financial, macroeconomic and policy uncertainty from the United States on the dynamics of credit growth, stock prices, economic activity, bond yields and inflation in five of the main receptors of US foreign direct investment from 1950 to 2019: The United Kingdom, The Netherlands, Ireland, Canada and Switzerland. Our multicounty approach allows us to clearly identify the effects of the different sources of uncertainty by imposing natural contemporaneous exogenity restrictions which cannot be used in a single-country perspective, frequently undertaken by the literature. It also considers international common cycle factors that have been previously identified and which are key to adequately measure the dynamics of the effects of uncertainty shocks on financial and real markets, on a global basis (...

Interdependent Capital Structure Choices and the Macroeconomy

This study shows that capital structure choices of US corporations are interdependent across time. We follow a two-step estimation approach. First, using a large cross-section of firms we estimate year-by-year average capital structure choices, i.e., the average firm’s percentage of new funding that is secured through debt, its term composition, and the percentage of new equity represented by retained earnings. Second, these time series are included in a Factor Augmented Vector Autoregressive model in which three factors representing real economic activity, expected future funding conditions, and prices, are included. We test for the interdependence between optimal capital structure decisions and for the influence exerted by macroeconomic conditions on these decisions. Results show there is a hierarchical order in which firms make capital structure decisions. They first decide on the share of debt out of total new funding they will hire. Conditional on this they decide on the term of their debt and on their earnings retention policy. Of outmost importance, macroeconomic factors are key for making capital structure decisions

Automatic plankton quantification using deep features

The study of marine plankton data is vital to monitor the health of the world’s oceans. In recent decades, automatic plankton recognition systems have proved useful to address the vast amount of data collected by specially engineered in situ digital imaging systems. At the beginning, these systems were developed and put into operation using traditional automatic classification techniques, which were fed with handdesigned local image descriptors (such as Fourier features), obtaining quite successful results. In the past few years, there have been many advances in the computer vision community with the rebirth of neural networks. In this paper, we leverage how descriptors computed using Convolutional Neural Networks (CNNs) trained with out-of-domain data are useful to replace hand-designed descriptors in the task of estimating the prevalence of each plankton class in a water sample. To achieve this goal, we have designed a broad set of experiments that show how effective these deep features are when working in combination with state-of-the-art quantification algorithms

Tin oxide preparation and characterization and use as a catalyst in the reaction of unsaturated fatty esters epoxidation

La síntesis y la caracterización del óxido de estaño se estudiaron en este trabajo para evaluar su actividad catalítica en la reacción de epoxidación del metilricinoleato proveniente del aceite de ricino. La obtención del óxido se realiza por el método de precipitación controlada, encontrándose que se obtienen ventajas significativas al emplear soluciones acuosas de SnCl2.2H2O como precursor. Su caracterización se efectuó por medio de las técnicas de DTA, TGA, DRX, encontrándose que para obtener un alto rendimiento hacia el sistema casiterita el valor de pH óptimo fue de 6.25, mientras que un pH de 8.0 conlleva hacia el sistema romarchita. En el caso de las técnicas de MEB y área superficial, se determinó que el tamaño de partícula encontrado estaba por debajo de los 50 nm con un área superficial de 19 m2/g. El ester ricinoleico se obtuvo a partir del aceite empleando metilato de sodio como catalizador y seguidamente se hace reaccionar con peróxido de hidrógeno como agente oxidante y óxido de estaño para producir un epóxido. Finalmente, los productos de reacción se identifican por cromatografía de gases, encontrando que los óxidos de estaño son activos para la obtención de epóxidos con un mejor desempeño del sistema cristalino romarchita (SnO) principalmente hacia el metil-12-hidroxi-9,10-epoxioctadecanoato (MHEOD). Abstract Tin oxide synthesis and characterization were studied in the present work in order to evaluate its catalytic activity in the reaction of methyl ricinoleate from castor oil. Oxide is obtained through the controlled precipitation method, and significant advantages are obtained when using water solutions of SnCl2.2H2O as precursor. Its characterization was done using the techniques DTA, TGA, XRD, finding that in order to have high performance for the cassiterite system the optimum pH value was 6,25 whereas a pH of 8.0 was leading to the romarchite system. When using SEM techniques and a surface area, the size of the particle found was below 50 nm with a surface area of 19 m2/g. The ricinoleate ester was obtained from the oil using sodium methylate as catalyst and then making it react with hydrogen peroxide as oxidant agent and tin oxide to produce an epoxide. Finally, reaction products are identified through gas chromatography finding that tin oxides are active for obtaining epoxides with better performance of the romarchite crystal system (SnO) especially towards the methyl-12-hydroxi-9, 10-epoxioctadecanote (MHEOD)

A systematic mapping study on testing technique experiments: has the situation changed since 2000?

Context: Empirical Software Engineering (ESE) replication researchers need to store and manipulate experimental data for several purposes, in particular analysis and reporting. Current research needs call for sharing and preservation of experimental data as well. In a previous work, we analyzed Replication Data Management (RDM) needs. A novel concept, called Experimental Ecosystem, was proposed to solve current deficiencies in RDM approaches. The empirical ecosystem provides replication researchers with a common framework that integrates transparently local heterogeneous data sources. A typical situation where the Empirical Ecosystem is applicable, is when several members of a research group, or several research groups collaborating together, need to share and access each other experimental results. However, to be able to apply the Empirical Ecosystem concept and deliver all promised benefits, it is necessary to analyze the software architectures and tools that can properly support it

Hábitats biogénicos como reguladores de la variabilidad de las comunidades bentónicas de invertebrados en la bahía de Tongoy (costa del Pacífico SE): implicaciones de la cosecha de macroalgas

Habitat biogenic complexity is thought to exert a significant positive influence on benthic communities. We examined the link between the seasonal variability of macroinvertebrate community structure (species and trophic richness, diversity and biomass) and habitats with different macroalgal assemblages. We identified macroinvertebrates and algae from 336 samples spread over four types of habitat: sand, mud, sand-gravel and seagrass meadows. Considering the whole macroalgal and macroinvertebrate assemblage, we confirmed that macroinvertebrate community variability within and among habitats can be mainly (but not only) explained by a few macroalgal structuring species. The variability of macroinvertebrate communities between habitats and seasons depended on the changes in the relative contribution of the explanatory biostructuring species in the overall algal community. Biomass, trophic behaviour and species richness remained stable in habitats with conspicuous macroalgal communities in contrast with habitats devoid of macroalgae. However, invertebrate species richness and biomass remained stable only in habitats whose dominant species did not change between seasons and not in those where dominant structuring species shifted. The seasonal change in a key structuring macroalgal species (Condracanthus chamissoi), probably as a result of harvesting, led to a major reduction in invertebrate community biomass and richness both in the particular habitat and in those nearby at species level. These consequences are especially important for invertebrates linked by trophic relationships and targeted by fisheries.La complejidad biogénica del hábitat ejercería una importante influencia positiva sobre las comunidades bentónicas. Examinamos la relación entre la variabilidad estacional de la estructura de las comunidades de macroinvertebrados (riqueza, diversidad y biomasa de especies y grupos tróficos) en hábitats con diferentes ensambles de macroalgas. Identificamos macroinvertebrados y algas en 336 muestras distribuidas en cuatro tipos de hábitats: arena, lodo, arena-grava y praderas de pastos marinos. En este estudio, considerando todo el conjunto de macroalgas y macroinvertebrados, confirmamos que la variabilidad de la comunidad de macroinvertebrados dentro y entre los hábitats puede ser explicada principalmente (pero no sólo) por unas pocas especies estructurantes de macroalgas. La variabilidad de la comunidad de macroinvertebrados entre hábitats y estaciones dependió de los cambios de la contribución relativa de las especies biostructurales explicativas en la comunidad algal. La biomasa, el comportamiento trófico y la riqueza de especies permanecieron estables en los hábitats con comunidades de macroalgas conspicuas, en contraste con los hábitats desprovistos de macroalgas. Sin embargo, la riqueza de especies de invertebrados y la biomasa sólo se mantuvieron estables en los hábitats cuyas especies dominantes no cambiaron entre estaciones, pero no en aquellos en los que las especies estructurantes dominantes cambiaron. El cambio estacional de una especie de macroalga estructurante clave (Condracanthus chamissoi), probablemente debido a su cosecha, tuvo importantes consecuencias en la reducción de la biomasa y la riqueza de la comunidad de invertebrados, tanto en su hábitat como en los hábitats adyacentes. Estas consecuencias son especialmente relevantes para los invertebrados vinculados por relaciones tróficas y que además son recursos pesqueros

Projections of Heat Waves Events in the Intra-Americas Region Using Multimodel Ensemble

Significant accelerated warming of the Sea Surface Temperature of 0.15°C per decade (1982–2012) was recently detected, which motivated the research for the present consequences and future projections on the heat index and heat waves in the intra-Americas region. Present records every six hours are retrieved from NCEP reanalysis (1948–2015) to calculate heat waves changes. Heat index intensification has been detected in the region since 1998 and driven by surface pressure changes, sinking air enhancement, and warm/weaker cold advection. This regional warmer atmosphere leads to heat waves intensification with changes in both frequency and maximum amplitude distribution. Future projections using a multimodel ensemble mean for five global circulation models were used to project heat waves in the future under two scenarios: RCP4.5 and RCP8.5. Massive heat waves events were projected at the end of the 21st century, particularly in the RCP8.5 scenario. Consequently, the regional climate change in the current time and in the future will require special attention to mitigate the more intense and frequent heat waves impacts on human health, countries’ economies, and energy demands in the IAR