13,966 research outputs found
Nonlocal Optics of Plasmonic Nanowire Metamaterials
We present an analytical description of the nonlocal optical response of
plasmonic nanowire metamaterials that enable negative refraction, subwavelength
light manipulation, and emission lifetime engineering. We show that dispersion
of optical waves propagating in nanowire media results from coupling of
transverse and longitudinal electromagnetic modes supported by the composite
and derive the nonlocal effective medium approximation for this dispersion. We
derive the profiles of electric field across the unit cell, and use these
expressions to solve the long-standing problem of additional boundary
conditions in calculations of transmission and reflection of waves by nonlocal
nanowire media. We verify our analytical results with numerical solutions of
Maxwell's equations and discuss generalization of the developed formalism to
other uniaxial metamaterials
Anomalous Phase Transition in Strained SrTiO Thin Films
We have studied the cubic to tetragonal phase transition in epitaxial
SrTiO films under various biaxial strain conditions using synchrotron X-ray
diffraction. Measuring the superlattice peak associated with TiO octahedra
rotation in the low temperature tetragonal phase indicates the presence of a
phase transition whose critical temperature is a strong function of strain,
with T as much as 50K above the corresponding bulk temperature.
Surprisingly, the lattice constants evolve smoothly through the transition with
no indication of a phase change. This signals an important change in the nature
of the phase transition due to the epitaxy strain and substrate clamping
effect. The internal degrees of freedom (TiO rotations) have become
uncoupled from the overall lattice shape.Comment: 4 pages, 3 figures, REVTeX
Compensatory Consumption and Consumer Compromises: A State of the Art Review
Compensatory consumption has been an increasingly researched yet widely debated area of consumer behaviour over the last 20 years. Extant research formulates the term as overwhelmingly negative, largely due to the simplistic and fragmented conceptualisations assumed in prior work. The purpose of the current paper is to present a comprehensive review of the umbrella term of compensatory consumption, incorporating a continuum of behaviours and accounting for the pre- and post-consumption periods including both positive and negative viewpoints. In addition, expanding upon the theory of need satisfaction, the current paper introduces a novel conceptual distinction between compensation and compromise. Finally, a proposed theoretical framework is presented that differentiates between compensatory and compromisory consumption based on the extent of consumer consciousness, rationality and rationalisation. Future research directions are offered
Cmah-dystrophin deficient mdx mice display an accelerated cardiac phenotype that is improved following peptide-PMO exon skipping treatment
Duchenne muscular dystrophy (DMD) is caused by loss of dystrophin protein, leading to progressive muscle weakness and premature death due to respiratory and/or cardiac complications. Cardiac involvement is characterized by progressive dilated cardiomyopathy, decreased fractional shortening and metabolic dysfunction involving reduced metabolism of fatty acids—the major cardiac metabolic substrate. Several mouse models have been developed to study molecular and pathological consequences of dystrophin deficiency, but do not recapitulate all aspects of human disease pathology and exhibit a mild cardiac phenotype. Here we demonstrate that Cmah (cytidine monophosphate-sialic acid hydroxylase)-deficient mdx mice (Cmah−/−;mdx) have an accelerated cardiac phenotype compared to the established mdx model. Cmah−/−;mdx mice display earlier functional deterioration, specifically a reduction in right ventricle (RV) ejection fraction and stroke volume (SV) at 12 weeks of age and decreased left ventricle diastolic volume with subsequent reduced SV compared to mdx mice by 24 weeks. They further show earlier elevation of cardiac damage markers for fibrosis (Ctgf), oxidative damage (Nox4) and haemodynamic load (Nppa). Cardiac metabolic substrate requirement was assessed using hyperpolarized magnetic resonance spectroscopy indicating increased in vivo glycolytic flux in Cmah−/−;mdx mice. Early upregulation of mitochondrial genes (Ucp3 and Cpt1) and downregulation of key glycolytic genes (Pdk1, Pdk4, Ppara), also denote disturbed cardiac metabolism and shift towards glucose utilization in Cmah−/−;mdx mice. Moreover, we show long-term treatment with peptide-conjugated exon skipping antisense oligonucleotides (20-week regimen), resulted in 20% cardiac dystrophin protein restoration and significantly improved RV cardiac function. Therefore, Cmah−/−;mdx mice represent an appropriate model for evaluating cardiac benefit of novel DMD therapeutics
The Effect of Oil Well Brines on Agricultural Fields and Water
What is Brine and Where Does it Come From? Brine is the salty water trapped in rock formations associated with oil and gas deposits. It consists mostly of sodium chloride but can also contain other things such as organics, bromide, some heavy metals and boron. Its source as a pollutant is usually oil stripper wells which produce less than 10 barrels of oil per day with typically a 10:1 ratio of brine to oil. Such wells are distributed throughout Kentucky and are often located on farmland. In some cases, brine rises to the land surface even where no oil wells are present
The metacognitions about smoking questionnaire : development and psychometric properties
The Metacognitions about Smoking Questionnaire was shown to possess good psychometric properties, as well as predictive and divergent validity within the populations that were tested. The metacognition factors explained incremental variance in smoking behaviour above smoking outcome expectancies
ARPES Study of the Metal-Insulator Transition in Bismuth Cobaltates
We present an angle-resolved photoemission spectroscopy (ARPES) study of a
Mott-Hubbard-type bismuth cobaltate system across a metal-insulator transition.
By varying the amount of Pb substitution, and by doping with Sr or Ba cation, a
range of insulating to metallic properties is obtained. We observe a systematic
change in the spectral weight of the coherent and incoherent parts, accompanied
by an energy shift of the incoherent part. The band dispersion also shows the
emergence of a weakly dispersing state at the Fermi energy with increasing
conductivity. These changes correspond with the changes in the
temperature-dependent resistivity behavior. We address the nature of the
coherent-incoherent parts in relation to the peak-dip-hump feature seen in
cuprates superconductors
Multifractal Scaling of Thermally-Activated Rupture Processes
We propose a ``multifractal stress activation'' model combining thermally
activated rupture and long memory stress relaxation, which predicts that
seismic decay rates after mainshocks follow the Omori law with
exponents linearly increasing with the magnitude of the mainshock and
the inverse temperature. We carefully test this prediction on earthquake
sequences in the Southern California Earthquake catalog: we find power law
relaxations of seismic sequences triggered by mainshocks with exponents
increasing with the mainshock magnitude by approximately for each
magnitude unit increase, from to ,
in good agreement with the prediction of the multifractal model.Comment: four pages and 2 figure
Development of a high-altitude airborne dial system: The Lidar Atmospheric Sensing Experiment (LASE)
The ability of a Differential Absorption Lidar (DIAL) system to measure vertical profiles of H2O in the lower atmosphere was demonstrated both in ground-based and airborne experiments. In these experiments, tunable lasers were used that required real-time experimenter control to locate and lock onto the atmospheric H2O absorption line for the DIAL measurements. The Lidar Atmospheric Sensing Experiment (LASE) is the first step in a long-range effort to develop and demonstrate an autonomous DIAL system for airborne and spaceborne flight experiments. The LASE instrument is being developed to measure H2O, aerosol, and cloud profiles from a high-altitude ER-2 (extended range U-2) aircraft. The science of the LASE program, the LASE system design, and the expected measurement capability of the system are discussed
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