Neutrinoless ββ\beta\beta decay nuclear matrix elements in an isotopic chain

We analyze nuclear matrix elements (NME) of neutrinoless double beta decay calculated for the Cadmium isotopes. Energy density functional methods including beyond mean field effects such as symmetry restoration and shape mixing are used. Strong shell effects are found associated to the underlying nuclear structure of the initial and final nuclei. Furthermore, we show that NME for two-neutrino double beta decay evaluated in the closure approximation, $M^{2\nu}_{\mathrm{cl}}$, display a constant proportionality with respect to the Gamow-Teller part of the neutrinoless NME, $M^{0\nu}_{\mathrm{GT}}$. This opens the possibility of determining the $M^{0\nu}_{\mathrm{GT}}$ matrix elements from $\beta^{\mp}$ Gamow-Teller strength functions. Finally, the interconnected role of deformation, pairing, configuration mixing and shell effects in the NMEs is discussed

Systematic study of infrared energy corrections in truncated oscillator spaces

We study the convergence properties of nuclear binding energies and two-neutron separation energies obtained with self-consistent mean-field calculations based on the Hartree-Fock-Bogolyubov (HFB) method with Gogny-type effective interactions. Owing to lack of convergence in a truncated working basis, we employ and benchmark one of the recently proposed infrared energy correction techniques to extrapolate our results to the limit of an infinite model space. We also discuss its applicability to global calculations of nuclear masses.Comment: 12 pages, 12 figure

Public financing with financial frictions and underground economy

What are the aggregate effects of informality in a financially constrained economy? We develop and calibrate an entrepreneurship model to data on matched employer-employee from both formal and informal sectors in Brazil. The model distinguishes between informality on the business side (extensive margin) and the informal hiring by formal firms (intensive margin). We find that when informality is eliminated along both margins, aggregate output increases 9.3%, capital 14.7%, TFP 5.4%, and tax revenue37%. The output and TFP increases would be much larger if informality were only eliminated on the extensive margin, a result that supports the view that the informal economy can play a positive role in an economy with financial frictions. Finally, we find that the output cost of financing social security in our baseline model is about twice as large as the one in an economy with no frictions

Testing the importance of collective correlations in neutrinoless ββ decay

We investigate the extent to which theories of collective motion can capture the physics that determines the nuclear matrix elements governing neutrinoless double-β decay. To that end we calculate the matrix elements for a series of isotopes in the full pf shell, omitting no spin-orbit partners. With the inclusion of isoscalar pairing, a separable collective Hamiltonian that is derived from the shell model effective interaction reproduces the full shell-model matrix elements with good accuracy. A version of the generator coordinate method that includes the isoscalar pairing amplitude as a coordinate also reproduces the shell model results well, an encouraging result for theories of collective motion, which can include more single-particle orbitals than the shell model. We briefly examine heavier nuclei relevant for experimental double-β decay searches, in which shell-model calculations with all spin-orbit partners are not feasible; our estimates suggest that isoscalar pairing also plays a significant role in these nuclei, though one we are less able to quantify precisely.This work was supported in part by an International Research Fellowship from the Japan Society for the Progress of Science (JSPS), and JSPS KAKENHI Grant No. 26·04323, by the Deutsche Forschungsgemeinschaft through Contract No. SFB 634, by the Helmholtz Association through the Helmholtz Alliance Program, Contract No. HA216/EMMI “Extremes of Density and Temperature: Cosmic Matter in the Laboratory”, by the European Research Council under Grant No. 307986 STRONGINT, by the U.S. Department of Energy through Contract No. DE-FG02-97ER41019, and by the Spanish MINECO under Programa Ramón y Cajal 11420 and FIS-2014-53434-

ZnO growth by MOCVD: numerical study

EnIII−V compound device fabrication is facing today challenging issues typically related to high volume manufacturing such as process reliability, process consistency, cost−reduction. Each step of the overall device manufacturing process must be carefully analysed and replicated to obtain reproducible device structures. Purifiers are commonly used in MOVPE processes and are becoming standard equipment in both research and production environments. In most cases implementation of gas purification strategies is enabling to achieve ultimate product purity and process reproducibility by defect and contamination control. In addition, an appropriate gas purification strategy is effective in high value component/chemicals protection (e.g. high purity MO sources), and as an assurance against line contamination due to human error or component failure. Purifier operating conditions can vary noticeably and a knowledge of which parameters can affect ultimate gas purity should be of interest to MOVPE operators to master gas distribution line contamination issues. Expertise on such parameters and their effect is essential to obtain a reliable product and sub−ppb contamination control throughout the purifier's lifetime and not only in spot demonstrations

Forecasting Adverse Weather Situations in the Road Network

Weather is an important factor that affects traffic flow and road safety. Adverse weather situations affect the driving conditions directly; hence, drivers must be informed about the weather conditions downstream to adapt their driving. In the framework of intelligent transport systems, several systems have been developed to know the weather situations and inform drivers. However, these systems do not forecast weather in advance, and they need the support of road operators to inform drivers. This paper presents a new autonomous system to forecast weather conditions in a short time and to give users the information obtained. The system uses a set of algorithms and rules to determine the weather and to forecast dangerous situations on the road network. It has been implemented using a multiagent approach and tested with real data. Results are very promising. The system is able to forecast adverse situations with a high degree of quality. This quality makes it possible to trust in the system and to avoid the supervision of operators

Estudio de la fluencia de una calcarenita: la Piedra de San Julián (Alicante)

Rocks creep has a great importance in the evaluation of the long-term behaviour of elements built with or within these materials. In this work, a porous well-known limestone locally named as San Julián stone has been physically and mechanically characterized. Uniaxial compressive tests for 96 h. at constant stress are carried out. Long-term behaviour has been modelled by means of a well-known creep model, the CEB-FIP Model code 2010, used for modelling other stony-material (i.e. concrete). Furthermore, a rheological model has been proposed. The main aim of this work is to investigate the possibility of exploiting the vast experience accumulated in the study of concrete deformational long-term behaviour in order to obtaining a reasonable approach to the behaviour of the rock, for too long testing times difficult to implement in laboratory. A creep function adapted to the studied rock only dependent on its elastic and mechanical characteristics is also proposed in this work.La fluencia de las rocas tiene gran importancia en la evaluación del comportamiento a largo plazo de elementos construidos con estos materiales. En este trabajo, se ha caracterizado física y mecánicamente una calcarenita porosa bien conocida localmente como Piedra de San Julián. Se han realizado ensayos de compresión uniaxial de 96 h. a carga constante. Se ha utilizado un modelo de fluencia bien conocido, el Código-modelo CEB-FIP 2010, usado para modelizar otro material pétreo (hormigón). Además, se ha propuesto un modelo reológico. El objetivo principal de este trabajo es investigar la posibilidad de aprovechar la gran experiencia acumulada en el estudio del hormigón, con el fin de obtener un enfoque para el comportamiento de la roca, para tiempos de prueba muy largos difíciles de implementar en laboratorio. Se propone una función de fluencia adaptada a la roca estudiada dependiente sólo de sus características elásticas y mecánicas

Riparian species and flow regime: ecological studies for application in environmental flow assessments and river restoration (Mijares river, Spain)

Riparian species and flow regime: ecological studies for application in environmental flow assessments and river restoration (Mijares river, Spain

Examination of the Feynman-Hibbs Approach in the Study of NeN_N-Coronene Clusters at Low Temperatures

Feynman-Hibbs (FH) effective potentials constitute an appealing approach for investigations of many-body systems at thermal equilibrium since they allow us to easily include quantum corrections within standard classical simulations. In this work we apply the FH formulation to the study of Ne$_N$-coronene clusters ($N=$ 1-4, 14) in the 2-14 K temperature range. Quadratic (FH2) and quartic (FH4) contributions to the effective potentials are built upon Ne-Ne and Ne-coronene analytical potentials. In particular, a new corrected expression for the FH4 effective potential is reported. FH2 and FH4 cluster energies and structures -obtained from energy optimization through a basin-hoping algorithm as well as classical Monte Carlo simulations- are reported and compared with reference path integral Monte Carlo calculations. For temperatures $T> 4$ K, both FH2 and FH4 potentials are able to correct the purely classical calculations in a consistent way. However, the FH approach fails at lower temperatures, especially the quartic correction. It is thus crucial to assess the range of applicability of this formulation and, in particular, to apply the FH4 potentials with great caution. A simple model of $N$ isotropic harmonic oscillators allows us to propose a means of estimating the cut-off temperature for the validity of the method, which is found to increase with the number of atoms adsorbed on the coronene molecule