37 research outputs found
Nanostructures Defined by The Local Oxidation of Ferromagnetic GaMnAs Layer
The results of Local Anodic Oxidation (LAO) on the thin GaMnAs layers are reported. The ferromagnetic GaMnAs layers were prepared by low temperature MBE growth in a Veeco Mod Gen II machine. The LAO process was performed with the AFM microscope Smena NT-MDT placed in the sealed box with the controlled humidity in the range 45-80%. The oxide was grown in the semi-contact mode of the AFM. Sample was positively biased with respect to the AFM tip with the bias from 6 to 24 V. The conductive diamond coated AFM tips with the radius 30 nm were utilized for the oxidation. The tip speed during the oxidation was changed from 400 nm/s to 1.5 μm/s. The tip force was also changed during the oxidation. The height of oxide nanolines increases with applied voltage from 3 to 18 nm. The width of these lines was approximately 100 nm at half of the maximum
Refining the prediction for OJ 287 next impact flare arrival epoch
The bright blazar OJ~287 routinely parades high brightness bremsstrahlung
flares which are explained as being a result of a secondary supermassive black
hole (SMBH) impacting the accretion disk of a primary SMBH in a binary system.
We begin by showing that these flares occur at times predicted by a simple
analytical formula, based on the Kepler equation, which explains flares since
1888. The next impact flare, namely the flare number 26, is rather peculiar as
it breaks the typical pattern of two impact flares per 12 year cycle. This will
be the third bremsstrahlung flare of the current cycle that follows the already
observed 2015 and 2019 impact flares from OJ~287. Unfortunately, astrophysical
considerations make it difficult to predict the exact arrival epoch of the
flare number 26. In the second part of the paper, we describe our recent OJ~287
observations. They show that the pre-flare light curve of flare number 22,
observed in 2005, exhibits similar activity as the pre-flare light curve in
2022, preceding the expected flare number 26 in our model. We argue that the
pre-flare activity most likely arises in the primary jet whose activity is
modulated by the transit of the secondary SMBH through the accretion disk of
the primary. Observing the next impact flare of OJ~287 in October 2022 will
substantiate the theory of disk impacts in binary black hole systems.Comment: 16 pages, 2 figure
Internet-based interventions for the secondary prevention of coronary heart disease
Background
The Internet could provide a means of delivering secondary prevention programmes to people with coronary heart disease (CHD).
Objectives
To determine the effectiveness of Internet-based interventions targeting lifestyle changes and medicines management for the secondary prevention of CHD.
Search methods
We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, in December 2014. We also searched six other databases in October 2014, and three trials registers in January 2015 together with reference checking and handsearching to identify additional studies.
Selection criteria
Randomised controlled trials (RCTs) evaluating Internet-delivered secondary prevention interventions aimed at people with CHD.
Data collection and analysis
Two review authors independently assessed risk of bias and extracted data according to the Cochrane Handbook for Systematic Reviews of Interventions. We assessed evidence quality using the GRADE approach and presented this in a 'Summary of findings' table