Cosmic Microwave Background temperature and polarization anisotropies from the large-N limit of global defects

We determine the full C_l spectra and correlation functions of the temperature and polarization anisotropies in the CMB, generated by a source modeled by the large N limit of spontaneously broken global O(N)-theories. We point out a problem in the standard approach of treating the radiation-matter transition by interpolating the eigenvectors of the unequal-time correlators of the source energy-momentum tensor. This affects the CMB predictions from all type of cosmic defects. We propose a method to overcome this difficulty, and find that in the large-N global model that we study, differences in the final CMB power spectra amplitudes reach up to 25%, when compared to implementations of the eigenvector interpolation technique. We discuss as well how to optimally search for the contribution in the CMB from active sources such as cosmic defects, in experiments like Planck, COrE and PRISM.Comment: 16+4 pages, 13 figures (Version 2: minor changes to match published version in PRD

The local B-polarization of the CMB: a very sensitive probe of cosmic defects

We present a new and especially powerful signature of cosmic strings and other topological or non-topological defects in the polarization of the cosmic microwave background (CMB). We show that even if defects contribute 1% or less in the CMB temperature anisotropy spectrum, their signature in the local $\tilde{B}$-polarization correlation function at angular scales of tens of arc minutes is much larger than that due to gravitational waves from inflation, even if the latter contribute with a ratio as big as $r\simeq 0.1$ to the temperature anisotropies. We show that when going from non-local to local $\tilde{B}$-polarization, the ratio of the defect signal-to-noise with respect to the inflationary value increases by about an order of magnitude. Proposed B-polarization experiments, with a good sensitivity on arcminute scales, may either detect a contribution from topological defects produced after inflation or place stringent limits on them. Even Planck should be able to improve present constraints on defect models by at least an order of magnitude, to the level of \ep <10^{-7}. A future full-sky experiment like CMBpol, with polarization sensitivities of the order of $1\mu$K-arcmin, will be able to constrain the defect parameter \ep=Gv^2 to a few $\times10^{-9}$, depending on the defect model.Comment: Version Published in Physics Letters

Coupled Negative magnetocapacitance and magnetic susceptibility in a Kagome staircase-like compound Co3V2O8

The dielectric constant of the Kagome staircase-like Co3V2O8 polycrystalline compound has been measured as function of temperature and magnetic field up to 14T. It is found that the application of an external magnetic field suppresses the anomaly for the dielectric constant beyond 6.1K. Furthermore, its magnetic field dependence reveals a negative magnetocapacitance which is proportional to the magnetic susceptibility, suggesting a common magnetostrictive origin for the magnetic field dependence of the two quantities. This result is very different from that obtained from the isostructural compound Ni3V2O8 that presents a peak in the dielectric constant at the incommensurate magnetic phase transition coupled to a sign change of the magnetocapacitance

La implementación de normas de seguridad industrial y la prevención de riesgos eléctricos en los laboratorios de la especialidad de electricidad de la Facultad de Tecnología de la UNE

La presente tesis tiene como objetivo principal, el proponer e implementar las normas de seguridad industrial y la prevención de riesgos eléctricos en los laboratorios de la especialidad de electricidad, con la finalidad de implementar, el plan de estudios la asignatura de “seguridad industrial y la prevención de riesgos eléctricos”

La implementación de normas de seguridad industrial y la prevención de riesgos eléctricos en los laboratorios de la especialidad de electricidad de la Facultad de Tecnología de la UNE

La presente tesis tiene como objetivo principal, el proponer e implementar las normas de seguridad industrial y la prevención de riesgos eléctricos en los laboratorios de la especialidad de electricidad, con la finalidad de implementar, el plan de estudios la asignatura de “seguridad industrial y la prevención de riesgos eléctricos”

The Power Spectrum for a Multi-Component Inflaton to Second-Order Corrections in the Slow-Roll Expansion

We derive the power spectrum $\mathcal P(k)$ of the density perturbations produced during inflation up to second-order corrections in the standard slow-roll approximation for an inflaton with more than one degree of freedom. We also present the spectral index $n$ up to first-order corrections including previously missing terms, and the running ${dn}/{d\ln k}$ to leading order.Comment: 11 pages, no figure. KAIST-TH 2002/0

Dielectric catastrophe at the magnetic field induced insulator to metal transition in Pr1-xCaxMnO3 (x=0.30, 0.37) crystals

The dielectric permittivity and resistivity have been measured simultaneously as a function of magnetic field in Pr1-xCaxMnO3 crystals with different doping. A huge increase of dielectric permittivity was detected near percolation threshold. The dielectric and conductive properties are found to be mutually correlated throughout insulator to metal transition evidencing the dielectric catastrophe phenomenon. Data are analyzed in a framework of Maxwell-Garnett theory and the Mott-Hubbard theory attributed to the role of strong Coulomb interactions.Comment: 5 pages, 5 figure

Inflationary models inducing non-Gaussian metric fluctuations

We construct explicit models of multi-field inflation in which the primordial metric fluctuations do not necessarily obey Gaussian statistics. These models are realizations of mechanisms in which non-Gaussianity is first generated by a light scalar field and then transferred into curvature fluctuations. The probability distribution functions of the metric perturbation at the end of inflation are computed. This provides a guideline for designing strategies to search for non-Gaussian signals in future CMB and large scale structure surveys.Comment: 4 pages, 7 figure

Baryogenesis by R-parity violating top quark decays and neutron-antineutron oscillations

Generation of the cosmological baryon asymmetry in SUSY based model with broken R-parity and low scale gravity is considered. The model allows for a long-life time or even stable proton and observable neutron-antineutron oscillations.Comment: 26 pages, 2 figures, uses axodraw.sty, added reference

Teaching to Get Nurses an Midwives Empowering Women: Nursing Students’ Perceptions on Professional´s Roles during Perinatal Care

Female empowerment is a key concept in the current healthcare environment, especially in perinatal care. The educational process offered by universities to train future nurses and midwives has a great influence on their professional attitude and performance. To be able to educate in a way that encourages empowerment, it is essential for higher education institutions to know the starting point relating to students’ opinions on the subject. It was conducted a cross-sectional descriptive observational study, at the University of Huelva. It used a self-developed, semi-structured questionnaire, previously validated, to gather quantitative and qualitative data. A total of 117 nursing student were surveyed. Participants consider that general nurses supplement the work of the midwife and acts as a facilitator for the process of women’s empowerment in the perinatal period. They believe that the midwife is the professional figure of reference and the one in which they place greater trust. Improvement proposals for both types of professionals are based on improving training and resources. To encourage the development of the profession and improve the quality of care, it is essential to introduce features related to women’s empowerment in the undergraduate training of future nurses and midwives