Search results for "ESOL"
showing 10 items of 2444 documents
Problemas Descriptivos de Fracciones
2016
Resumen En este trabajo se presenta un estudio sobre los problemas verbales de fracciones que ha transmitido la tradición escolar. Se trata de problemas descriptivos, porque su contexto es una historieta o narración pseudorealista que no pretende dar respuesta a ninguna situación verdaderamente práctica. Mediante el análisis didáctico e histórico-epistemológico se aporta claridad metodológica sobre estos problemas de fracciones, al identificar sus distintos tipos, sus estructuras, sus lecturas analíticas, sus reglas, fórmulas y métodos de resolución.
Parallel fractional correlation: an optical implementation
2008
An optical setup to obtain all the fractional correlations of a one-dimensional input in a single display is implemented. The system works as a multichannel parallel correlator for a continuous set of fractional orders and presents a variable shift variance. Some experimental results together with computer simulations are performed to illustrate the performance of our proposal.
Impact of the Agent’s Environment on Discretion in the Field of EU Conflict Resolution
2017
Employing an agent–principal perspective on EU conflict resolution and focusing on the politics of discretion, we argue that the context in which the agent acts affects the principal–agent relation. Our conceptualization draws on the agent’s actions as a source of discretion, which can be either an unintentional product of the characteristics of the external environment in which the agent performs (structure-induced discretion) or a product of intentionally pursued agent action (interest-induced discretion). Focusing particularly on the European External Action Service, we find that the agent can exploit urgency and third party interplay as characteristics of EU conflict resolution in order…
Ultrafast Metamorphosis of a Complex Charge Density Wave in Tantalumdiselenite
2016
Using ultrafast electron diffraction, we record the transformation between a nearly-commensurate and an incommensurate charge-density-wave in 1T-TaS2, which takes place orders of magnitude faster than previously observed for commensurate-to-incommensurate transitions.
Pseudo-bosons and Riesz Bi-coherent States
2016
After a brief review on D-pseudo-bosons we introduce what we call Riesz bi-coherent states, which are pairs of states sharing with ordinary coherent states most of their features. In particular, they produce a resolution of the identity and they are eigenstates of two different annihilation operators which obey pseudo-bosonic commutation rules.
A Scanning Electron Microscope for Ultracold Atoms
2006
We propose a new technique for the detection of single atoms in ultracold quantum gases. The technique is based on scanning electron microscopy and employs the electron impact ionization of trapped atoms with a focussed electron probe. Subsequent detection of the resulting ions allows for the reconstruction of the atoms position. This technique is expected to achieve a much better spatial resolution compared to any optical detection method. In combination with the sensitivity to single atoms, it makes new in situ measurements of atomic correlations possible. The detection principle is also well suited for the addressing of individual sites in optical lattices.
High-resolution scanning electron microscopy of an ultracold quantum gas
2008
Our knowledge of ultracold quantum gases is strongly influenced by our ability to probe these objects. In situ imaging combined with single-atom sensitivity is an especially appealing scenario, as it can provide direct information on the structure and the correlations of such systems. For a precise characterization a high spatial resolution is mandatory. In particular, the perspective to study quantum gases in optical lattices makes a resolution well below one micrometre highly desirable. Here, we report on a novel microscopy technique, which is based on scanning electron microscopy and allows for the detection of single atoms inside a quantum gas with a spatial resolution of better than 15…
From atomic to molecular Bose-Einstein condensates: a physically realizable term-crossing model for cold atom association
2010
Using an exact third-order NL di®erential equation for the molecular state probability, we develop a variational approach which enables us to construct highly accurate analytic approximations describing time dynamics of the coupled atom-molecular system in each of the interaction regimes. We show that the approximation describing time evolution of the molecular state probability both in the weak interaction limit and in the large detuning regime of the strong interaction limit can be written as a sum of two distinct terms; the ¯rst one, being a solution to a limit ¯rst-order NL equation, e®ectively describes the process of the molecule formation while the second one, being a scaled solution…
Valence band photoemission from thin iron films - A comparison of experimental and theoretical results
1998
Abstract In this contribution, we report on photoemission data from thin iron films on W(110) that have been carried out by means of spin-resolved photoelectron spectroscopy as well as Magnetic Circular Dichroism in valence band photoemission at the storage ring BESSY. These techniques give complementary information on the electronic and magnetic properties, such as exchange and spin–orbit splitting. We compare our experimental data to new photoemission calculations, which have been obtained in the framework of a fully relativistic one-step theory for ferromagnetic materials.
Auto calibration of a cone-beam-CT
2012
Purpose: This paper introduces a novel autocalibration method for cone-beam-CTs (CBCT) or flat-panel CTs, assuming a perfect rotation. The method is based on ellipse-fitting. Autocalibration refers to accurate recovery of the geometric alignment of a CBCT device from projection images alone, without any manual measurements. Methods: The authors use test objects containing small arbitrarily positioned radio-opaque markers. No information regarding the relative positions of the markers is used. In practice, the authors use three to eight metal ball bearings (diameter of 1 mm), e.g., positioned roughly in a vertical line such that their projection image curves on the detector preferably form l…