Photovoltaic effect in ferroelectric ceramics

The ceramic structure was simulated in a form that is more tractable to correlation between experiment and theory. Single crystals (of barium titanate) were fabricated in a simple corrugated structure in which the pedestals of the corrugation simulated the grain while the intervening cuts could be filled with materials simulating the grain boundaries. The observed photovoltages were extremely small (100 mv)

Protecting Chrysanthemums from Disease

Now\u27s the time to take steps to assure fall color from chrysanthemums. Though mums are susceptible to a number of diseases, a few preventive steps will hold problems to a minimum

Lower bounds for several online variants of bin packing

We consider several previously studied online variants of bin packing and prove new and improved lower bounds on the asymptotic competitive ratios for them. For that, we use a method of fully adaptive constructions. In particular, we improve the lower bound for the asymptotic competitive ratio of online square packing significantly, raising it from roughly 1.68 to above 1.75.Comment: WAOA 201

Magnetic resonance imaging of myocardial strain after acute ST-segment-elevation myocardial infarction: a systematic review

The purpose of this systematic review is to provide a clinically relevant, disease-based perspective on myocardial strain imaging in patients with acute myocardial infarction or stable ischemic heart disease. Cardiac magnetic resonance imaging uniquely integrates myocardial function with pathology. Therefore, this review focuses on strain imaging with cardiac magnetic resonance. We have specifically considered the relationships between left ventricular (LV) strain, infarct pathologies, and their associations with prognosis. A comprehensive literature review was conducted in accordance with the PRISMA guidelines. Publications were identified that (1) described the relationship between strain and infarct pathologies, (2) assessed the relationship between strain and subsequent LV outcomes, and (3) assessed the relationship between strain and health outcomes. In patients with acute myocardial infarction, circumferential strain predicts the recovery of LV systolic function in the longer term. The prognostic value of longitudinal strain is less certain. Strain differentiates between infarcted versus noninfarcted myocardium, even in patients with stable ischemic heart disease with preserved LV ejection fraction. Strain recovery is impaired in infarcted segments with intramyocardial hemorrhage or microvascular obstruction. There are practical limitations to measuring strain with cardiac magnetic resonance in the acute setting, and knowledge gaps, including the lack of data showing incremental value in clinical practice. Critically, studies of cardiac magnetic resonance strain imaging in patients with ischemic heart disease have been limited by sample size and design. Strain imaging has potential as a tool to assess for early or subclinical changes in LV function, and strain is now being included as a surrogate measure of outcome in therapeutic trials

Energy Density-Flux Correlations in an Unusual Quantum State and in the Vacuum

In this paper we consider the question of the degree to which negative and positive energy are intertwined. We examine in more detail a previously studied quantum state of the massless minimally coupled scalar field, which we call a ``Helfer state''. This is a state in which the energy density can be made arbitrarily negative over an arbitrarily large region of space, but only at one instant in time. In the Helfer state, the negative energy density is accompanied by rapidly time-varying energy fluxes. It is the latter feature which allows the quantum inequalities, bounds which restrict the magnitude and duration of negative energy, to hold for this class of states. An observer who initially passes through the negative energy region will quickly encounter fluxes of positive energy which subsequently enter the region. We examine in detail the correlation between the energy density and flux in the Helfer state in terms of their expectation values. We then study the correlation function between energy density and flux in the Minkowski vacuum state, for a massless minimally coupled scalar field in both two and four dimensions. In this latter analysis we examine correlation functions rather than expectation values. Remarkably, we see qualitatively similar behavior to that in the Helfer state. More specifically, an initial negative energy vacuum fluctuation in some region of space is correlated with a subsequent flux fluctuation of positive energy into the region. We speculate that the mechanism which ensures that the quantum inequalities hold in the Helfer state, as well as in other quantum states associated with negative energy, is, at least in some sense, already ``encoded'' in the fluctuations of the vacuum.Comment: 21 pages, 7 figures; published version with typos corrected and one added referenc

Plant Disease Outcome in 1967

The influence of disease on crops and trees will be decided by a large number of interacting factors. Most of the diseases responsible for loss and profit in crops can be eliminated by preventive measures you and your neighbors take

Using directed-content analysis to identify a framework for understanding quality of life in adults with Rett syndrome

Purpose: Rett syndrome (RTT) is a rare neurodevelopmental disorder mainly affecting females and is caused by a mutation in the MECP2 gene. Recent research identified the domains of quality of life (QOL) important for children with RTT but there has been no investigation of domains important for adults. This qualitative study explored QOL in adults with RTT and compared domains with those previously identified for children. Methods: The sample comprised parents and/or primary caregivers of 20 adults, aged 18–38 years, who were registered with the Australian Rett Syndrome Database. Semi-structured telephone interviews were conducted to investigate aspects of life that were observed to be satisfying or challenging. Data were analyzed using directed content analysis, based on existing QOL domains for children with RTT that related to health and wellbeing, daily activities, and community immersion and services. Results: Each of the domains identified for children with RTT was represented in the adult dataset, with no new domains emerging. Conclusion: This is the first study to identify QOL domains important for adults with RTT. Health and therapy needs are ongoing during adulthood but services may be limited. Findings will guide choice of an appropriate QOL measure for this group.IMPLICATIONS FOR REHABILITATION Knowing the important domains of quality of life enables clinicians and service providers to systematically review and address key management issues. Despite a high level of dependency and sometimes poor health, parent caregivers perceive potential for strong quality of life in adulthood. Services that maintain functional skills and health throughout the lifespan are valued for their support of quality of life in adults with Rett syndrome

Fabrication and Characterization of Modulation-Doped ZnSe/(Zn,Cd)Se (110) Quantum Wells: A New System for Spin Coherence Studies

We describe the growth of modulation-doped ZnSe/(Zn,Cd)Se quantum wells on (110) GaAs substrates. Unlike the well-known protocol for the epitaxy of ZnSe-based quantum structures on (001) GaAs, we find that the fabrication of quantum well structures on (110) GaAs requires significantly different growth conditions and sample architecture. We use magnetotransport measurements to confirm the formation of a two-dimensional electron gas in these samples, and then measure transverse electron spin relaxation times using time-resolved Faraday rotation. In contrast to expectations based upon known spin relaxation mechanisms, we find surprisingly little difference between the spin lifetimes in these (110)-oriented samples in comparison with (100)-oriented control samples.Comment: To appear in Journal of Superconductivity (Proceedings of 3rd Conference on Physics and Applications of Spin-dependent Phenomena in Semiconductors