640 research outputs found
Influence of the Lower Hybrid Drift Instability on the onset of Magnetic Reconnection
Two-dimensional and three-dimensional kinetic simulation results reveal the
importance of the Lower-Hybrid Drift Instability LHDI to the onset of magnetic
reconnection. Both explicit and implicit kinetic simulations show that the LHDI
heats electrons anisotropically and increases the peak current density. Linear
theory predicts these modifications can increase the growth rate of the tearing
instability by almost two orders of magnitude and shift the fastest growing
modes to significantly shorter wavelengths. These predictions are confirmed by
nonlinear kinetic simulations in which the growth and coalescence of small
scale magnetic islands leads to a rapid onset of large scale reconnection
990-53 Effects on Cardiovascular End Points and Psychological Variables of Metoprolol and Verapamil in Patients with Stable Angina Pectoris â The Angina Prognosis Study in Stockholm (APSIS)
The effect of treatment with metoprolol or verapamil was investigated in 809 patients with stable angina pectoris. End points for the study were: death, nonfatal cardiovascular events and three psychological variables reflecting aspects of quality of life. Nonfatal cardiovascular events included acute myocardial infarction, incapacitating or unstable angina, cerebrovascular and peripheral vascular events. The psychological variables were aggregate measures of psychosomatic symptoms and sleep disturbances and an evaluation of life satisfaction on a visual analogue scale. The mean age of the patients was 59±7 years and 30% were women. The patients were followed for a total of 2887 patient years, with a median follow-up time of 3.6 years. Total cardiovascular mortality in the metoprolol versus verapamit group were 5.4% versus 6.2% and 4.7% versus 4.7% respectively. Nonfatal cardiovascular events occurred in 26.4 and 24.1%, respectively. Psychosomatic symptoms and sleep disturbances were significantly improved in both treatment groups. The magnitude of change was small and not significantly different. Life satisfaction did not change on either drug. Withdrawals due to side effects occurred in 11.1 and 14.6%, respectively.ConclusionThis large scale long term study shows that both drugs were well tolerated and had the same effect on mortality, cardiovascular end points and measures of quality of life
Cosmic Ray Acceleration by Spiral Shocks in the Galactic Wind
Cosmic ray acceleration by shocks related with Slipping Interaction Regions
(SIRs) in the Galactic Wind is considered. SIRs are similar to Solar Wind
Corotating Interaction Regions. The spiral structure of our Galaxy results in a
strong nonuniformity of the Galactic Wind flow and in SIR formation at
distances of 50 to 100 kpc. SIRs are not corotating with the gas and magnetic
field because the angular velocity of the spiral pattern differs from that of
the Galactic rotation. It is shown that the collective reacceleration of the
cosmic ray particles with charge in the resulting shock ensemble can
explain the observable cosmic ray spectrum beyond the "knee" up to energies of
the order of eV. For the reaccelerated particles the Galactic Wind
termination shock acts as a reflecting boundary.Comment: LATEX, 14 pages, 7 figures, accepted to A&
Three-Dimensional Fermi Surface of Overdoped La-Based Cuprates
We present a soft x-ray angle-resolved photoemission spectroscopy study of
the overdoped high-temperature superconductors LaSrCuO and
LaEuSrCuO. In-plane and out-of-plane components of
the Fermi surface are mapped by varying the photoemission angle and the
incident photon energy. No dispersion is observed along the nodal
direction, whereas a significant antinodal dispersion is identified.
Based on a tight-binding parametrization, we discuss the implications for the
density of states near the van-Hove singularity. Our results suggest that the
large electronic specific heat found in overdoped LaSrCuO can
not be assigned to the van-Hove singularity alone. We therefore propose quantum
criticality induced by a collapsing pseudogap phase as a plausible explanation
for observed enhancement of electronic specific heat
Neutron powder diffraction study of NaMnO and LiMnO: New insights on spin-charge-orbital ordering
The high-pressure synthesized quasi-one-dimensional compounds NaMnO
and LiMnO are both antiferromagnetic insulators, and here
their atomic and magnetic structures were investigated using neutron powder
diffraction. The present crystal structural analyses of NaMn2O4 reveal that
Mn3+/Mn4+ charge-ordering state exist even at low temperature (down to 1.5 K).
It is evident from one of the Mn sites shows a strongly distorted Mn3+
octahedra due to the Jahn-Teller effect. Above TN = 39 K, a two-dimensional
short-range correlation is observed, as indicated by an asymmetric diffuse
scattering. Below TN, two antiferromagnetic transitions are observed (i) a
commensurate long-range Mn3+ spin ordering below 39 K, and (ii) an
incommensurate Mn4+ spin ordering below 10 K. The commensurate magnetic
structure (kC = 0.5, -0.5, 0.5) follows the magnetic anisotropy of the local
easy axes of Mn3+, while the incommensurate one shows a spin-density-wave order
with kIC = (0,0,0.216). For LiMnO, on the other hand, absence
of a long-range spin ordered state down to 1.5 K is confirmed.Comment: 11 pages, 8 figure
Heterogeneity after harmonisation: a retrospective cohort study of bleeding and stroke risk after the introduction of direct oral anticoagulants in four Western European countries
Purpose: Database heterogeneity can impact effect estimates. Harmonisation provided by common protocols and common data models (CDMs) can increase the validity of pharmacoepidemiologic research. In a case study measuring the changes in the safety and effectiveness of stroke prevention therapy after the introduction of direct oral anticoagulants (DOACs), we performed an international comparison. Methods: Using data from Stockholm, Denmark, Scotland and Norway, harmonised with a common protocol and CDM, two calendar-based cohorts were created: 2012 and 2017. Patients with a diagnosis code of atrial fibrillation 5 years preceding the 1-year cohort window were included. DOAC, vitamin K antagonist and aspirin treatment were assessed in the 6 months prior to the start of each year while strokes and bleeds were assessed during the year. A Poisson regression generated incidence rate ratios (IRRs) to compare outcomes from 2017 to 2012 adjusted for changes in individual-level baseline characteristics. Results: In 280 359 patients in the 2012 cohort and 356 779 in the 2017 cohort, treatment with OACs increased on average from 45% to 65%, while treatment with aspirin decreased from 30% to 10%. In all countries except Scotland, there were decreases in the risk of stroke and no changes in bleeding risk, after adjustment for changes in baseline characteristics. In Scotland, major bleeding (IRR 1.09, 95% confidence interval [CI] [1.00; 1.18]) and intracranial haemorrhage (IRR 1.31, 95% CI [1.13; 1.52]) increased from 2012 to 2017. Conclusions: Stroke prevention therapy improved from 2012 to 2017 with a corresponding reduction in stroke risk without increasing the risk of bleeding in all countries, except Scotland. The heterogeneity that remains after methodological harmonisation can be informative of the underlying population and database
InParanoid 7: new algorithms and tools for eukaryotic orthology analysis
The InParanoid project gathers proteomes of completely sequenced eukaryotic species plus Escherichia coli and calculates pairwise ortholog relationships among them. The new release 7.0 of the database has grown by an order of magnitude over the previous version and now includes 100 species and their collective 1.3 million proteins organized into 42.7 million pairwise ortholog groups. The InParanoid algorithm itself has been revised and is now both more specific and sensitive. Based on results from our recent benchmarking of low-complexity filters in homology assignment, a two-pass BLAST approach was developed that makes use of high-precision compositional score matrix adjustment, but avoids the alignment truncation that sometimes follows. We have also updated the InParanoid web site (http://InParanoid.sbc.su.se). Several features have been added, the response times have been improved and the site now sports a new, clearer look. As the number of ortholog databases has grown, it has become difficult to compare among these resources due to a lack of standardized source data and incompatible representations of ortholog relationships. To facilitate data exchange and comparisons among ortholog databases, we have developed and are making available two XML schemas: SeqXML for the input sequences and OrthoXML for the output ortholog clusters
Magnetism and Ion Diffusion in Honeycomb Layered Oxide KNiTeO: First Time Study by Muon Spin Rotation & Neutron Scattering
In the quest of finding novel and efficient batteries, a great interest has
raised in K-based honeycomb layer oxide materials both for their fundamental
properties and potential applications. A key issue in the realization of
efficient batteries based on such compounds, is to understand the K-ion
diffusion mechanism. However, investigation of potassium-ion (K) dynamics
in materials using magneto-spin properties has so far been challenging, due to
its inherently weak nuclear magnetic moment, in contrast to other alkali ions
such as lithium and sodium. Spin-polarised muons, having a high gyromagnetic
ratio, make the muon spin rotation and relaxation (+SR) technique ideal
for probing ions dynamics in weak magneto-spin moment materials. Here we report
the magnetic properties and K+ dynamics in honeycomb layered oxide material of
the KNiTeO using +SR measurements. Our low-temperature
+SR results together with, with complementary magnetic susceptibility,
find an antiferromagnetic transition at 26 K. Further +SR studies
performed at higher temperatures reveal that potassium ions (K) become
mobile above 250 K and the activation energy for the diffusion process is Ea =
121(13) meV. This is the first time that K+ dynamics in potassium-based battery
materials has been measured using +SR. Finally our results also indicate
an interesting possibility that K-ion self diffusion occurs predominantly at
the surface of the powder particles. This opens future possibilities for
improving ion diffusion and device performance using nano-structuring.Comment: 12 pages, 12 figure
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