Search results for "Zone"

Shaping Brillouin Light in Specialty Optical Fibers

2017

Magnetic excitations of a doped two-dimensional antiferromagnet

1993

Magnetic excitations of the two-dimensional (2D) t-J model are considered in the presence of a small concentration of holes c. The spin-wave approximation used implies long-range antiferromagnetic ordering from the beginning. Migdal's theorem is shown to be valid for the model considered. The energy spectrum of the magnons is determined with the help of the one-pole approximation for the hole Green's function. If the concentration of mobile holes is larger than a critical value an additional branch of overdamped magnons arises near the \ensuremath{\Gamma} and M points of the Brillouin zone. This is connected with the generation of electron-hole pairs (the Stoner excitations) by magnons. The…

Theoretical modeling of antiferrodistortive phase transition forSrTiO3ultrathin films

2013

Combining group-theoretical analysis and first-principles density functional theory calculations, we confirm theoretically the antiferrodistortive phase transition in ultrathin SrTiO${}_{3}$ (001) TiO${}_{2}$-terminated films and compare it with a similar transition in the bulk. We demonstrate phonon softening at the $M$ point of the surface Brillouin zone and analyze the change in the calculated electronic and phonon properties upon phase transition.

Giant Dzyaloshinskii-Moriya Interaction and Room-Temperature Nanoscale Skyrmions in CoFeB/MgO Heterostructures

2021

Magnetic skyrmions in heavy metal (HM)/CoFeB/MgO structures are of particular interest for skyrmion-based magnetic tunnel junction (MTJ) devices because of their reliable generation, stability and read-out through purely electrical methods. To optimize the properties, such as stability, a strong Dzyaloshinskii-Moriya interaction (DMI) is required at room temperature. Here, using first-principles calculations, we demonstrate that giant DMI can be obtained in Ir/CoFe structures with an Fe-terminated configuration. Moreover, Brillouin light scattering measurements show that indeed Ta/Ir/Co20Fe60B20/MgO thin films with perpendicular magnetic anisotropy exhibit a large DMI value (1.13 mJ/m2), wh…

Combination of ozonation and photocatalysis for purification of aqueous effluents containing formic acid as probe pollutant and bromide ion

2014

The treatment by advanced oxidation processes (AOPs) of waters contaminated by organic pollutants and containing also innocuous bromide ions may generate bromate ions as a co-product. In the present work heterogeneous photocatalysis and ozonation have individually been applied and in combination (integrated process) to degrade the organic compounds in water containing also bromide anions. The results show that: i) the sole photocatalysis does not produce bromate ions and in the case of its presence, it is able to reduce bromate to innocuous bromide ions; ii) the integration of photocatalysis and ozonation synergistically enhances the oxidation capabilities; and iii) in the integrated proces…

Piranesi Prix de Roma. INTERNATIONAL SEMINAR OF STUDIES ON ARCHITECTURE FOR ARCHAEOLOGY

2018

Tivoli Amusement Park Tour Guide

2019

The Tivoli Amusement Park is one of the largest amusement parks in the World, the total area is 250 hectares. It includes many attractions, some are very recent and others were made several years ago, but all of them are still able to arouse curiosity and fun for young and old people. Some people says that it's the only 2nd oldest surviving amusement park, untouched until today, after the one of Dyrehavsbakken, near Copenhagen. But these are only rumors, because by visiting the Tivoli Amusement Park it will be possible to undoubtedly remove this thoughts. The Tivoli Amusement Park is divided into 5 large entertainment areas: the Cardo & Decumano, the Aniene Water Park, Villa d'Este, the…

Detection of protection benefits for predatory fishes depends on census methodology

2021

Marine protected areas (MPAs) are used as fisheries management and conservation tools. Well-enforced no-take zones allow the rebuilding of natural populations of exploited species; however, there is still controversy on the role of buffer zones. The effectiveness of MPAs could be underestimated, as fish population assessments depend largely on traditional methodologies that have difficulties in detecting predatory fish because of their low abundances, their patchy distribution, and their reaction to the presence of divers. The performance of different census methods was compared in assessing the protection benefits for large predatory fishes under different protection levels (i.e. no-take a…

Barrier effects on the spatial distribution of Xylella fastidiosa in Alicante, Spain

2021

AbstractSpatial models often assume isotropy and stationarity, implying that spatial dependence is direction invariant and uniform throughout the study area. However, these assumptions are violated when dispersal barriers are present in the form of geographical features or disease control interventions. Despite this, the issue of non-stationarity has been little explored in the context of plant health. The objective of this study was to evaluate the influence of different barriers in the distribution of the quarantine plant pathogenic bacterium Xylella fastidiosa in the demarcated area in Alicante, Spain. Occurrence data from the official surveys in 2018 were analyzed with four spatial Baye…

Expression of Putative Fatty Acid Transporter Genes Are Regulated by Peroxisome Proliferator-activated Receptor α and γ Activators in a Tissue- and I…

1998

Regulation of gene expression of three putative long-chain fatty acid transport proteins, fatty acid translocase (FAT), mitochondrial aspartate aminotransferase (mAspAT), and fatty acid transport protein (FATP), by drugs that activate peroxisome proliferator-activated receptor (PPAR) alpha and gamma were studied using normal and obese mice and rat hepatoma cells. FAT mRNA was induced in liver and intestine of normal mice and in hepatoma cells to various extents only by PPARalpha-activating drugs. FATP mRNA was similarly induced in liver, but to a lesser extent in intestine. The induction time course in the liver was slower for FAT and FATP mRNA than that of an mRNA encoding a peroxisomal en…