The de Almeida–Thouless Line in Hierarchical Quantum Spin Glasses

We determine explicitly and discuss in detail the effects of the joint presence of a longitudinal and a transversal (random) magnetic field on the phases of the Random Energy Model and its hierarchical generalization, the GREM. Our results extent known results both in the classical case of vanishing transversal field and in the quantum case for vanishing longitudinal field. Following Derrida and Gardner, we argue that the longitudinal field has to be implemented hierarchically also in the Quantum GREM. We show that this ensures the shrinking of the spin glass phase in the presence of the magnetic fields as is also expected for the Quantum Sherrington–Kirkpatrick model.

The rapidly oscillating Ap star γ Equ: linear polarization as an enhanced pulsation diagnostic?

ABSTRACT We present the first short time-scale observations of the rapidly oscillating Ap (roAp) star γ Equ in linear polarized light obtained with the Potsdam Echelle Polarimetric and Spectroscopic Instrument installed at the Large Binocular Telescope. These observations are used to search for pulsation variability in Stokes Q and U line profiles belonging to different elements. The atmospheres of roAp stars are significantly stratified with spectral lines of different elements probing different atmospheric depths. roAp stars with strong magnetic fields, such as γ Equ with a magnetic field modulus of 4 kG and a pulsation period of 12.21 min, are of special interest because the effect of the magnetic field on the structure of their atmospheres can be studied with greatest detail and accuracy. Our results show that we may detect changes in the transversal field component in Fe i and rare earth element lines possessing large second-order Landé factors. Such variability can be due to the impact of pulsation on the transverse magnetic field, causing changes in the obliquity angles of the magnetic force lines. Further studies of roAp stars in linear polarized light and subsequent detailed modelling are necessary to improve our understanding of the involved physics.

Application of Platelet Rich Fibrin, Platelet Rich Plasma, Plasma Rich Growth Factors in Different Fields of Dentistry: An Overview

A huge number of studies have demonstrated that platelet-rich preparations applied to surgical sites, injuries, or wounds are effective way to promote soft tissue healing and bone growth. The potential use of platelet rich preparations like Platelet - rich plasma and Platelet - rich fibrin are new boon to dentistry termed under the general acronyms PRP (Platelet-Rich Plasma) or PRF (Platelet-Rich Fibrin), is an important current transversal field of research across many fundamental and clinical disciplines.The third important is PRGF. Plasma Rich in Growth Factor (or PRGF) is a type of plasma enriched of proteins and circulating growth factors able to aid the bone and soft tissue regeneration. PRGF includes plasma proteins and coagulative factors and is then more valuable compared to PRP. There are many scientific literature which cover one or other concise aspect of platelet rich preparation. This review aims at covering all basic definitions, key element, history, preparation, differences between PRF and PRP and applications in a simplified manner.

Análisis de capas PML en una región de campo electromagnético utilizando el Método de Diferencias Finitas en el Dominio del Tiempo

The Finite Difference in Time Domain (FDTD) method is currently one of the most used electromagnetism methods in electromagnetic field simulation, however, in order to obtain reliable results from this simulation it is necessary to have optimal boundary conditions. Perfectly Coupled Layers (PML) is characterized by the decomposition of the transversal field to the direction of propagation in its rectangular projections, and the use of both electrical and magnetic conductivity in the numerical layers for the absorption of electromagnetic fields. The PML layers are characterized by values of permittivity, permeability and conductivity that are assigned to each of the equations according to their position in the region. Because it is the same set of equations there is no need to use connection conditions at the junction of the analysis region with the PML absorption region, which provides a natural transition throughout the region. This paper presents the study of the difference between the calculation region with and without PML layers.

Ibero-American Research on Local Development. An Analysis of Its Evolution and New Trends

Local development is a subject that arouses significant interest in the international scientific community in general, and in the Ibero-American one, in particular. The process of globalization has transformed the management of local development, altering the role that is played by local and regional entities, and it is the object of an important follow-up and analysis by academia. This research uses a bibliometric methodology and a fractional counting method, reviewing the 738 articles from the Scopus database in order to understand the state of Ibero-American research on local development, and analyze the scientific literature on the topic. The results show a significant increase in the number of publications in the 21st century, with Spain and Brazil leading the way. In addition, this research provides interesting results regarding the most influential authors on this topic, the most relevant journals, and the most important institutions and funding organizations. There are several areas of knowledge involved since local development is a transversal field, such as Social Science, environment, business, economics, and agriculture. A deep analysis of authors’ keywords identified new trends, linking local development with tourism, education, geotourism, climate change, local sustainable development, social innovation, and creativity, which provides academia with potential new lines of research.

Selective Soldering on Printed Circuit Boards with Endogenous Induction Heat at Appropriate Susceptors

In this work, methods for the endogenous heating of printed circuit boards (PCBs) by means of inductive losses in built-in susceptors are presented. Two basic types of inductive heating were studied, the heating in the transversal field and the heating in the longitudinal field. Elementary test stands were constructed and characterized for both field geometries. These setups were then used to analyze various susceptor materials like copper and aluminum for the transversal field heating and nickel and iron for the longitudinal field heating. To demonstrate the soldering processes by means of inductive heating, exemplary processes were conducted on both test stands by emulating a standard solder reflow profile. The limitations of using induction heating on printed circuit boards are illustrated by component lead frames, which also heat up in the inductive field and can hence be damaged.In short, this paper presents a selective heating method, based on induction heating, for printed circuit boards. Furthermore possible setups for implementing this heating method are described.