Local density of states in metal - topological superconductor hybrid systems

We study by means of the recursive Green's function technique the local density-of-states of (finite and semi-infinite) multi-band spin-orbit coupled semiconducting nanowires in proximity to an s-wave superconductor and attached to normal-metal electrodes. When the nanowire is coupled to a normal electrode, the zero-energy peak, corresponding to the Majorana state in the topological phase, broadens with increasing transmission between the wire and the leads, eventually disappearing for ideal interfaces. Interestingly, for a finite transmission a peak is present also in the normal electrode, even though it has a smaller amplitude and broadens more rapidly with the strength of the coupling. Unpaired Majorana states can survive close to a topological phase transition even when the number of open channels (defined in the absence of superconductivity) is even. We finally study the Andreev-bound-state spectrum in superconductor-normal metal-superconductor junctions and find that in multi-band nanowires the distinction between topologically trivial and non-trivial systems based on the number of zero-energy crossings is preserved.Comment: 11 pages, 12 figures, published versio

Dark Monopoles in Grand Unified Theories

We consider a Yang-Mills-Higgs theory with gauge group $G=SU(n)$ broken to $G_{v} = [SU(p)\times SU(n-p)\times U(1)]/Z$ by a Higgs field in the adjoint representation. We obtain monopole solutions whose magnetic field is not in the Cartan Subalgebra. Since their magnetic field vanishes in the direction of the generator of the electromagnetic group $U(1)_{em}$, we call them Dark Monopoles. These Dark Monopoles must exist in some Grand Unified Theories (GUTs) without the need to introduce a dark sector. We analyze the particular case of $SU(5)$ GUT, where we obtain that their mass is $M = 4\pi v \widetilde{E}(\lambda/e^{2})/e$, where $\widetilde{E}(\lambda/e^{2})$ is a monotonically increasing function of $\lambda/e^{2}$ with $\widetilde{E}(0)=1.294$ and $\widetilde{E}(\infty)=3.262.$ We also give a geometrical interpretation to their non-abelian magnetic charge.Comment: 22 pages; added some comments on possible cosmological implications of Dark Monopoles in the last section and added some references. Published Versio

Welcome to the Neighborhood: Does Where you Live Affect the Use of Nutrition, Health, and Welfare Programs?

Despite the recent upsurge in neighborhood effects research, few studies have examined the impact of neighborhood characteristics on the use of nutrition, health, and welfare programs. To explore these issues, this study used data from Welfare, Children, and Families: A Three-City Study, a longitudinal dataset comprised of low-income neighborhoods in Boston, San Antonio, and Chicago (n=1,712). Using hierarchical linear models, the results indicated that both individual (education, employment, and marriage) and perceived neighborhood disorder factors were related to social service use

La nueva regulaci\uf2n del contrato por proyecto en el ordenamiento italiano

El estudio, desde la perspectiva de una reconstrucci\uf3n general del trabajo econ\uf3micamente dependiente en el ordenamiento italiano, examina las modificaciones que introdujo la Ley de reforma del mercado de trabajo de 2012 en el contrato por proyecto y en la regulaci\uf3n de otros tipos de trabajo por cuenta propia, como las \u2013as\ued llamadas\u2013 falsas partite IV

The AMBRE Project: Parameterisation of FGK-type stars from the ESO:HARPS archived spectra

The AMBRE project is a collaboration between the European Southern Observatory (ESO) and the Observatoire de la Cote d'Azur (OCA). It has been established to determine the stellar atmospheric parameters (effective temperature, surface gravity, global metallicities and abundance of alpha-elements over iron) of the archived spectra of four ESO spectrographs. The analysis of the ESO:HARPS archived spectra is presented. The sample being analysed (AMBRE:HARPS) covers the period from 2003 to 2010 and is comprised of 126688 scientific spectra corresponding to 17218 different stars. For the analysis of the spectral sample, the automated pipeline developed for the analysis of the AMBRE:FEROS archived spectra has been adapted to the characteristics of the HARPS spectra. Within the pipeline, the stellar parameters are determined by the MATISSE algorithm, developed at OCA for the analysis of large samples of stellar spectra in the framework of galactic archaeology. In the present application, MATISSE uses the AMBRE grid of synthetic spectra, which covers FGKM-type stars for a range of gravities and metallicities. We first determined the radial velocity and its associated error for the ~15% of the AMBRE:HARPS spectra, for which this velocity had not been derived by the ESO:HARPS reduction pipeline. The stellar atmospheric parameters and the associated chemical index [alpha/Fe] with their associated errors have then been estimated for all the spectra of the AMBRE:HARPS archived sample. Based on quality criteria, we accepted and delivered the parameterisation of ~71% of the total sample to ESO. These spectra correspond to ~10706 stars; each are observed between one and several hundred times. This automatic parameterisation of the AMBRE:HARPS spectra shows that the large majority of these stars are cool main-sequence dwarfs with metallicities greater than -0.5 dex

SwSt 1: an O-rich planetary nebula around a C-rich central star

The hydrogen-deficient carbon-rich [WCL] type central star HD167362 and its oxygen-rich planetary nebula (PN) SwSt~1 are investigated. The nebular chemistry might indicate a recent origin for the carbon-rich stellar spectrum. Its stellar and nebular properties might therefore provide further understanding of the origin of the [WCL] central star class. The UV-IR stellar spectra are modelled with state of the codes and show ~40kK central star with a wind and a C/O~3, indicative of efficient third dredge-up. The synthetic stellar flux distribution is used to model the high density, compact PN, which has a solar C/O ratio, is still enshrouded by 1200K and 230K dust shells and, reported here for the first time, in molecular hydrogen. Although it appears that the change in C/O ratio has been recent, the published spectroscopy since 1895 has been re-examined and no clear spectral change is seen. If an event occurred that has turned it into a hydrogen-deficient central star, it did not happen in the last 100 years.Comment: 31 pages, 19 figures (some are gif files), MNRAS in pres

\u3cem\u3ePromises I Can Keep: Why Poor Women put Motherhood before Marriage.\u3c/em\u3e Kathryn Edin and Maria Kefalas.

Book note for Kathryn Edin and Maria Kefalas, Promises I can Keep: Why Poor Women put Motherhood before Marriage. Berkeley, CA: University of California Press, 2005. $24.95 hardcover,$15.95 papercover

Global analysis of fragmentation functions for pions and kaons and their uncertainties

We present new sets of pion and kaon fragmentation functions obtained in NLO combined analyses of single-inclusive hadron production in electron-positron annihilation, proton-proton collisions, and deep-inelastic lepton-proton scattering with either pions or kaons identified in the final state. At variance with all previous fits, the present analyses take into account data where hadrons of different electrical charge are identified, which allow to discriminate quark from anti-quark fragmentation functions without the need of non trivial flavor symmetry assumptions. The resulting sets are in good agreement with all data analyzed, which cover a much wider kinematical range than in previous fits. An extensive use of the Lagrange multiplier technique is made in order to assess the uncertainties in the extraction of the fragmentation functions and the synergy from the complementary data sets in our global analysis.Comment: 28 pages, 25 figure