Recent advancement of turbulent flow measurement techniques

Advancements of the fluctuating density gradient cross beam laser Schlieren technique, the fluctuating line-reversal temperature measurement and the development of the two-dimensional drag-sensing probe to a three-dimensional drag-sensing probe are discussed. The three-dimensionality of the instantaneous momentum vector can shed some light on the nature of turbulence especially with swirling flow. All three measured fluctuating quantities (density, temperature, and momentum) can provide valuable information for theoreticians

Epitaxial Growth of La1/3_{1/3}Sr2/3_{2/3}FeO3_3 thin films by laser ablation

We report on the synthesis of high quality La$_{1/3}$Sr$_{2/3}$FeO$_3$ (LSFO) thin films using the pulsed laser deposition technique on both SrTiO$_3$ (STO) and LaAlO$_3$ (LAO) substrates (100)-oriented. From X-Ray diffraction (XRD) studies, we find that the films have an out-of-plane lattice parameter around 0.3865nm, almost independent of the substrate (i.e. the nature of the strains). The transport properties reveal that, while LSFO films deposited on STO exhibit an anomaly in the resistivity vs temperature at 180K (corresponding to the charge-ordered transition and associated with a transition from a paramagnetic to an antiferromagnetic state), the films grown on LAO display a very small magnetoresistance behavior and present an hysteresis around 270K under the application of a 4T magnetic field. The changes in transport properties between both substrates are discussed and compared with the corresponding single crystals.Comment: 9 pages, 4 figure

A note on cluster expansions, tree graph identities, extra 1/ N ! factors!!!

We draw attention to a new tree graph identity which substantially improves on the usual tree graph method of proving convergence of cluster expansions in statistical mechanics and quantum field theory. We can control expansions that could not be controlled before.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43217/1/11005_2004_Article_BF00420041.pd

Sparsity driven ultrasound imaging

An image formation framework for ultrasound imaging from synthetic transducer arrays based on sparsity-driven regularization functionals using single-frequency Fourier domain data is proposed. The framework involves the use of a physics-based forward model of the ultrasound observation process, the formulation of image formation as the solution of an associated optimization problem, and the solution of that problem through efficient numerical algorithms. The sparsity-driven, model-based approach estimates a complex-valued reflectivity field and preserves physical features in the scene while suppressing spurious artifacts. It also provides robust reconstructions in the case of sparse and reduced observation apertures. The effectiveness of the proposed imaging strategy is demonstrated using experimental data

Orbital Structure and Magnetic Ordering in Layered Manganites: Universal Correlation and Its Mechanism

Correlation between orbital structure and magnetic ordering in bilayered manganites is examined. A level separation between the $3d_{3z^2-r^2}$ and $3d_{x^2-y^2}$ orbitals in a Mn ion is calculated in the ionic model for a large number of the compounds. It is found that the relative stability of the orbitals dominates the magnetic transition temperatures as well as the magnetic structures. A mechanism of the correlation between orbital and magnetism is investigated based on the theoretical model with the two $e_g$ orbitals under strong electron correlation.Comment: 4 pages, 4 figure

Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide

We sampled interstitial air from the perennial snowpack (firn) at a site near the West Antarctic Ice Sheet Divide (WAIS-D) and analyzed the air samples for a wide variety of gas species and their isotopes. We find limited convective influence (1.4–5.2 m, depending on detection method) in the shallow firn, gravitational enrichment of heavy species throughout the diffusive column in general agreement with theoretical expectations, a ~10 m thick lock-in zone beginning at ~67 m, and a total firn thickness consistent with predictions of Kaspers et al. (2004). Our modeling work shows that the air has an age spread (spectral width) of 4.8 yr for CO<sub>2</sub> at the firn-ice transition. We also find that advection of firn air due to the 22 cm yr<sup>−1</sup> ice-equivalent accumulation rate has a minor impact on firn air composition, causing changes that are comparable to other modeling uncertainties and intrinsic sample variability. Furthermore, estimates of Δage (the gas age/ice age difference) at WAIS-D appear to be largely unaffected by bubble closure above the lock-in zone. Within the lock-in zone, small gas species and their isotopes show evidence of size-dependent fractionation due to permeation through the ice lattice with a size threshold of 0.36 nm, as at other sites. We also see an unequivocal and unprecedented signal of oxygen isotope fractionation within the lock-in zone, which we interpret as the mass-dependent expression of a size-dependent fractionation process

Presentació

Obra col·lectiva biennal, creada per l'Institut de la Comunicació de la Universitat Autònoma de Barcelona (InCom-UAB), l'any 2000. La desena edició, corresponent al bienni 2017-2018, va comptar amb el suport de la Generalitat de Catalunya; el patrocini de Naturgy; la col·laboració de l'Ajuntament de Barcelona; la subscripció institucional de la Societat Catalana de Comunicació (filial de l'Institut d'Estudis Catalans); i la col·laboració científica de Comscore, Estudio General de Medios (EGM)/Asociación para la Investigación de Medios de Comunicación (AIMC), l'Observatori de la Comunicació a Catalunya, i el Portal de la Comunicació (InCom-UAB).En el marc del Grup Internacional d'Estudis sobre Comunicació i Cultura (InCom-UAB), reconegut com a Grup Consolidat de Recerca de la Generalitat de Catalunya per al període 2017-2020 (Referència de concessió 2017 SGR 00760).Aquest text que esteu llegint és la presentació de la desena edició de l'Informe de la comunicació a Catalunya. Arribar a aquest nombre de publicacions -i, a més a més, respectant i mantenint els compromisos adquirits des d'un bon principi- no ha estat gens fàcil. És més, aquesta fita hauria estat impossible sense el suport de la Generalitat de Catalunya, de Naturgy (abans Gas Natural Fenosa) i de la Universitat Autònoma de Barcelona, on té la seva seu l'Institut de la Comunicació (InCom-UAB). Cal tenir en compte que estem parlant d'un projecte acadèmic que ha estat capaç d'analitzar, edició rere edició, tots els canvis viscuts a la indústria del sector comunicatiu català i la preocupació del qual, per tant, per establir i consolidar vincles entre la universitat i l'empresa no és un fet recent, sinó que forma part de la seva essència

www.niss.org Construction of Full Sample and Replicate Weights for Project Talent, with Applications

Project Talent is a large, nationally representative longitudinal study developed by the American Institutes for Research and conducted from 1960 to 1974. The goals were to assess the interests, abilities, and demographics of 9 th –12 th graders and to follow their trajectories into adulthood. More than 1,200 junior and senior high schools participated. Replicate weights were not constructed at the time, preventing the estimation of standard errors. Today, Project Talent is being revived to study the physical, cognitive, economic, and social processes of aging. In this paper, the retrospective construction of 104 sets of student-level replicate weights is described. Partitioning analysis was performed to generate variance strata and variance primary sampling units. The student-level replicate weights were constructed using a jackknife procedure. The process included adjustment of the base year weights and calibration of (full sample and replicate weights) to the total number of secondary school students in the U. S. in the spring of 1960. The use of replicate weights is illustrated by estimating standard errors for means of composite cognitive scores constructed from student questionnaires. We also describe construction of mortality- and nonresponse-adjusted weights for the thre

Relation between crystal and magnetic structures of the layered manganites La2-2xSr1+2xMn2O7 (0.30 =< x =< 0.50)

Comprehensive neutron-powder diffraction and Rietveld analyses were carried out to clarify the relation between the crystal and magnetic structures of La2-2xSr1+2xMn2O7 (0.30 =< x =< 0.50). The Jahn-Teller (JT) distortion of Mn-O6 octahedra, i.e., the ratio of the averaged apical Mn-O bond length to the equatorial Mn-O bond length, is Delta_JT=1.042(5) at x=0.30, where the magnetic easy-axis at low temperature is parallel to the c axis. As the JT distortion becomes suppressed with increasing x, a planar ferromagnetic structure appears at x =< 0.32, which is followed by a canted antiferromagnetic (AFM) structure at x =< 0.39. The canting angle between neighboring planes continuously increases from 0 deg (planar ferromagnet: 0.32 =< x < 0.39) to 180 deg (A-type AFM: x=0.48 where Delta_JT=1.013(5)). Dominance of the A-type AF structure with decrease of JT distortion can be ascribed to the change in the eg orbital state from d3z^2-r^2 to dx^2-y^2