Dielectric anisotropy and phonon modes of ordered indirect-gap Al\u3csub\u3e0.52\u3c/sub\u3eIn\u3csub\u3e0.48\u3c/sub\u3eP studied by far-infrared ellipsometry

The infrared (100–600 cm−1) optical properties of partially CuPt-type ordered Al0.52In0.48P deposited lattice matched on GaAs are studied by ellipsometry. The authors determine the ordinary and extraordinary dielectric functions and report on the evolution of the optical phonon mode frequencies of Al0.52In0.48P as a function of the degree of ordering. In addition to the InP- and AlP-like phonon modes, they observe two alloy-induced phonon modes which are anisotropic upon CuPt ordering. The observed modes are associated to vibrations with E and A1 symmetries. The alloy-induced phonon modes are useful for classifying the degree of ordering in this indirect band gap alloy

Statistical Models for Infectious Disease Surveillance Counts

Models for infectious disease surveillance counts have to take into account the specific characteristics of this type of data. While showing a regular, often seasonal, pattern over long time periods, there are occasional irregularities or outbreaks. A model which is a compromise between mechanistic models and empirical models is proposed. A key idea is to distinguish between an endemic and an epidemic component, which allows to separate the regular pattern from the irregularities and outbreaks. This is of particular advantage for outbreak detection in public health surveillance. While the endemic component is parameter-driven, the epidemic component is based on observationdriven approaches, including an autoregression on past observations. A particular challenge of infectious disease counts is the modelling of the outbreaks and irregularities in the data. We model the autoregressive parameter of the epidemic component by a Bayesian changepoint model, which shows an adaptive amount of smoothing, and is able to model the jumps and fast increases as well as the smooth decreases in the data. While the model can be used as a generic approach for infectious disease counts, it is particularly suited for outbreak detection in public health surveillance. Furthermore, the predictive qualities of the Bayesian changepoint model allow for short term predictions of the number of disease cases, which are of particular public health interest. A sequential update using a particle filter is provided, that can be used for a prospective analysis of the changepoint model conditioning on fixed values for the other parameters, which is of particular advantage for public health surveillance. A suitable multivariate extension is provided, that is able to explain the interactions between units, e.g. age groups or spatial regions. An application to influenza and meningococcal disease data shows that the occasional outbreaks of meningococcal disease can largely be explained by the influence of influenza on meningococcal disease. The risk of a future meningococcal disease outbreak caused by influenza can be predicted. The comparison of the different models, including a model based on Gaussian Markov random fields shows that the inclusion of the epidemic component as well as a time varying epidemic parameter improves the fit and the predictive qualities of the model

Zum zeitlichen Zusammenhang zwischen der Verschiebung der selektiven visuellen Aufmerksamkeit und den Bewegungen der Augen

Was wird zuerst verlagert und was folgt hinterher? Bei der Betrachtung der menschlichen Wahrnehmung spielen die Verlagerung des Orts der visuellen Aufmerksamkeit und die Verlagerung des Fixationsorts eine wichtige Rolle. Zur Reihenfolge, in der beide verlagert werden, existieren unterschiedliche Annahmen und Forschungsergebnisse, die vorgestellt werden. Es werden zwei zu dieser Thematik durchgeführte Experimente berichtet, in denen versucht wurde, vorliegende widersprüchliche Forschungsergebnisse zu integrieren. Es sollte gezeigt werden, dass neben der Aufmerksamkeit weitere Einflussgrößen existieren, die in Hinsicht auf diese Widersprüche Erklärungskraft besitzen. Mittels Bildbetrachtung und darauf folgender Wiedererkennensaufgaben wurde bestätigt, dass zu Beginn einer Fixation häufiger Ort und Inhalt der vorangegangenen Fixation angegeben werden. Dies wird nicht als ein Hinterherhinken der Aufmerksamkeit, sondern als Indiz für eine verzögerte Verarbeitung der Fixationsinhalte interpretiert. Im zweiten Experiment wurde zudem gezeigt, dass es kaum möglich ist, den Inhalt spezifischer vergangener Fixationen – hier konkret der vorletzten – gezielt zu erinnern

TERAHERTZ RESONATOR

A tunable terahertz resonator includes a semiconductor Substrate and a metal layer contacting a surface of the semiconductor substrate. A depletion layer is formed in the semiconductor substrate near an interface between the metal layer and the semiconductor Substrate. A chiral nanostructure is coupled to the substrate or the metal layer, the chiral nanostructure including a conducting or semiconducting material and having an inductance. A bias circuit applies a bias Voltage across the metal layer and the semiconductor Substrate to control a capacitance of a tunable capacitor that includes the depletion layer. The chiral nanostructure and the tunable capacitor form a tunable resonant circuit. The tunable terahertz resonator can be used in a terahertz radiation emitter or receiver

POLARIZATION-COUPLED FERROELECTRIC UNPOLARUNCTION MEMORY AND ENERGY STORAGE DEVICE

A memory device is provided. The memory device includes a plurality of memory cells and a controller to write data to and read data from the memory cells. Each memory cell includes a first semiconductor material having a spontaneous polarization, a resistive ferroelectric material having a switchable spontaneous polarization, and a second semiconductor material having a spontaneous polarization, the resistive ferroelectric material being positioned between and in contact with the first and second semiconductor materials. The memory device can be configured to store energy that can be released by applying a voltage pulse to the memory device

Muddying the Waters: reconsidering Migration in the Neolithic of Britain, Ireland and Denmark

This paper explores the current narratives of migration for the start and spread of the Neolithic with a particular focus on the role that the new ancient DNA data have provided. While the genetic data are important and instructive, here it is argued that archaeologists should also consider other strands of evidence. More nuanced appreciations of migration as a long-term process can be created by exploring modern mobility studies alongside considerations of continued mobility throughout the Neolithic in Europe. We can also re-interpret the material evidence itself in the light of these approaches to help trace multiple possible links and migrations from multiple different origin points. This involves the investigation of complex, but connected, practices, such as monument construction and deposition across wider areas of northern Europe than are currently normally investigated. Such an approach will enable us to address long-term processes of movement, migration and interaction and investigate how new, shared social experiences emerged in a setting in which mobility and migration may have been the norm

COMBINED USE OF OSCILLATING MEANS AND ELLIPSOMETRY TO DETERMINE UNCORRELATED EFFECTIVE THICKNESS AND OPTICAL CONSTANTS OF MATERIAL DEPOSITED AT OR ETCHED FROM A WORKING ELECTRODE THAT PREFERRABLY COMPRISES NON - NORMAL ORIENTED NANOFIBERS

Disclosed are systems and methods that enable determination of uncorrelated thickness of a working electrode and surface region optical constants in settings involving electrochemical processing at a working electrodes in a Piezo electric Balance system , by simultaneous application of an Ellipsometer system , the working electrode optionally having a multiplicity of nanofibers that are oriented non normally to a surface of said working electrode . Further disclosed is , simultaneous with said determinations , the monitoring of electrochemical processes at a piezoelectric balance working electrode driven by electrical energy applied between said working electrode and counter electrode

Infrared Dielectric Anisotropy and Phonon Modes of Rutile TiO2

Spectroscopic ellipsometry in the mid-infrared and far-infrared spectral range and generalized ellipsometry in the mid-infrared spectral range are used to investigate the anisotropic dielectric response of rutile TiO2. The ordinary and extraordinary dielectric function tensor components and all infrared active phonon mode parameters of single crystalline rutile TiO2 are determined with high accuracy for wavelengths from 3 μm to 83 μm. The data were acquired from samples of (001), (100), and (111) surfaces cut from bulk single crystals. A factorized model dielectric function is employed in order to determine the frequencies and damping parameters of the transverse and longitudinal phonon modes with A2u and Eu symmetries. The bands of total reflection of s- and p-polarized light in dependence of the angle of incidence for highly symmetric sample cuts and orientations are derived. Excellent agreement with phonon modes reported in literature is obtained. Introduction of two additional modes for ordinary as well as extraordinary component of the dielectric function tensor was necessary to most accurately match the experimental data. The spectral position of the additional modes is compared to the calculated phonon density of states. The low-frequency dielectric constants are calculated from the determined phonon mode parameters and the high-frequency dielectric constants by applying the Lyddanne-Sachs-Teller relation. The presented data revise existing infrared optical function data and will be suitable for interpretation of any kind of infrared spectra for bulk TiO2 single crystal substrates, thin films, and TiO2 nanostructures

Empirical Correction for Spectroscopic Ellipsometric Measurements of Rough or Textured Surfaces

A method of applying spectroscopic ellipsometry to arrive at accurate values of optical and physical properties for thin films on samples having rough or textured surfaces