Electronic structure and transport properties of atomic NiO spinvalves

Ab-initio quantum transport calculations show that short NiO chains suspended in Ni nanocontacts present a very strong spin-polarization of the conductance. The generalized gradient approximation we use here predicts a similiar polarization of the conductance as the one previously computed with non-local exchange, confirming the robustness of the result. Their use as nanoscopic spinvalves is proposed.Comment: 2 pages, 1 figure; accepted in JMMM (Proceedings of ICM'06, Kyoto

Investigation of plant growth and transpiration-induced matric suction under mixed grass-tree conditions

Although evapotranspiration-induced matric suction for single species has been widely studied, little is known about how mixed-species planting would affect the plant growth and induced matric suction. This study aims to explore the effects of grass-tree interaction on their growth and induced matric suction during evapotranspiration (ET) and rainfalls. Field monitoring was carried out to measure matric suction responses in compacted soil that was vegetated with (i) single tree species, Schefflera heptaphylla and (ii) mixed species of the trees and a grass species, Cynodon dactylon. In each condition, three tree spacings (120, 180 and 240 mm) were planted. When tree spacing increased from 120 to 240 mm, the peak tree root area index (RAI, for fine roots with diameterThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Argon plasma treatment techniques on steel and effects on diamond-like carbon structure and delamination

Copyright © 2011 Elsevier B.V. All rights reserved.We demonstrate alteration in diamond-like carbon (DLC) film structure, chemistry and adhesion on steel, related to variation in the argon plasma pretreatment stage of plasma enhanced chemical vapour deposition. We relate these changes to the alteration in substrate structure, crystallinity and chemistry due to application of an argon plasma process with negative self bias up to 600 V. Adhesion of the DLC film to the substrate was assessed by examination of the spallated fraction of the film following controlled deformation. Films with no pretreatment step immediately delaminated. At 300 V pretreatment, the spallated fraction is 8.2%, reducing to 1.2% at 450 V and 0.02% at 600V. For bias voltages below 450V the adhesion enhancement is explained by a reduction in carbon contamination on the substrate surface, from 59at.% with no treatment to 26at.% at 450V, concurrently with a decrease in the surface roughness, Rq, from 31.5nm to 18.9nm. With a pretreatment bias voltage of 600V a nanocrystalline, nanostructured surface is formed, related to removal of chromium and relaxation of stress; X-ray diffraction indicates this phase is incipient at 450V. In addition to improving film adhesion, the nanotexturing of the substrate prior to film deposition results in a DLC film that shows an increase in sp3/sp2 ratio from 1.2 to 1.5, a reduction in surface roughness from 31nm to 21nm, and DLC nodular asperities with reduced diameter and increased uniformity of size and arrangement. These findings are consistent with the substrate alterations due to the plasma pretreatment resulting in limitation of surface diffusion in the growth process. This suggests that in addition to deposition phase processes, the parameters of the pretreatment process need to be considered when designing diamond-like carbon coatings.This work is partially supported by the Technology Strategy Board, reference BD266E

Hamiltonian dynamics and spectral theory for spin-oscillators

We study the Hamiltonian dynamics and spectral theory of spin-oscillators. Because of their rich structure, spin-oscillators display fairly general properties of integrable systems with two degrees of freedom. Spin-oscillators have infinitely many transversally elliptic singularities, exactly one elliptic-elliptic singularity and one focus-focus singularity. The most interesting dynamical features of integrable systems, and in particular of spin-oscillators, are encoded in their singularities. In the first part of the paper we study the symplectic dynamics around the focus-focus singularity. In the second part of the paper we quantize the coupled spin-oscillators systems and study their spectral theory. The paper combines techniques from semiclassical analysis with differential geometric methods.Comment: 32 page

Twenty five years after KLS: A celebration of non-equilibrium statistical mechanics

When Lenz proposed a simple model for phase transitions in magnetism, he couldn't have imagined that the "Ising model" was to become a jewel in field of equilibrium statistical mechanics. Its role spans the spectrum, from a good pedagogical example to a universality class in critical phenomena. A quarter century ago, Katz, Lebowitz and Spohn found a similar treasure. By introducing a seemingly trivial modification to the Ising lattice gas, they took it into the vast realms of non-equilibrium statistical mechanics. An abundant variety of unexpected behavior emerged and caught many of us by surprise. We present a brief review of some of the new insights garnered and some of the outstanding puzzles, as well as speculate on the model's role in the future of non-equilibrium statistical physics.Comment: 3 figures. Proceedings of 100th Statistical Mechanics Meeting, Rutgers, NJ (December, 2008

Covid-19 pandemic impact on colonoscopy service and suggestions for managing recovery

Abstract Background and aim As the post-peak phase of the epidemic is approaching, there is an urgent need of an action plan to help resume endoscopy activity. To manage the Covid-19 pandemic-imposed backlog of postponed colonoscopy examinations, an efficient approach is needed. The practice of on-demand sedation with benzodiazepines and/or opiates will allow most patients to complete a water-aided examination with minimal or no sedation. Other methods reported to minimize patient discomfort during colonoscopy can be used, in addition to water-aided techniques. Unsedated or minimally sedated patients who do not require recovery or require a shorter one allow rapid turnaround. The practice obviates the need for assistance with deep sedation from anesthesiologists, who may be in short supply. Trainee education in water-aided colonoscopy has been demonstrated to confer benefits. This review provides some insights into the impact of Covid-19 on endoscopy services, challenges ahead, and possible solutions to help recovery of colonoscopy work and training

Prevalence and Prognostic Relevance of Ventricular Conduction Disturbances in Patients With Aortic Stenosis

Cardiolog

Searching for solar siblings in APOGEE and Gaia DR2 with N-body simulations

Computational astrophysic

Fulminant hyperpyrexia induced by bleomycin

Mild and self-limiting fever following bleomycin use is common, and a fatal hyperpyrexial response occurs rarely. In previously reported cases, such hyperpyrexia occurred either after the initial administration of the drug or during subsequent therapy following an initial pyrexial response. We describe a fatal hyperpyrexial reaction after bleomycin in a patient with T-cell lymphoma who had had no febrile response when she received her initial injection 3 weeks earlier. Since the occurrence of this hyperpyrexial response is unpredictable, health care workers as well as patients and relatives should always be alert to this potentially lethal complication and prompt measures should be taken in any patient who develops fever after bleomycin use.published_or_final_versio

Influence of Aging on Level and Layer-Specific Left Ventricular Longitudinal Strain in Subjects Without Structural Heart Disease

Cardiolog