1,567 research outputs found
Influence of topography and Co domain walls on the magnetization reversal of the FeNi layer in FeNi/AlO/Co magnetic tunnel junctions
We have studied the magnetization reversal dynamics of FeNi/AlO/Co
magnetic tunnel junctions deposited on step-bunched Si substrates using
magneto-optical Kerr effect and time-resolved x-ray photoelectron emission
microscopy combined with x-ray magnetic circular dichroism (XMCD-PEEM).
Different reversal mechanisms have been found depending on the substrate miscut
angle. Larger terraces (smaller miscut angles) lead to a higher nucleation
density and stronger domain wall pinning. The width of domain walls with
respect to the size of the terraces seems to play an important role in the
reversal. We used the element selectivity of XMCD-PEEM to reveal the strong
influence of the stray field of domain walls in the hard magnetic layer on the
magnetic switching of the soft magnetic layer.Comment: 8 Pages, 7 Figure
Performance-Based Compensation in Member-Owned Firms: An Examination of Medical Group Practices
We examine the importance of agency considerations for the mix of salary and performance-based compensation in member-owned medical practices. Performance-based pay increases with the informativeness of clinical productivity measures, and declines with greater reimbursement from capitation contracts. Inexperienced physicians receive more compensation from salary, but compensation mix does not change as physicians near retirement. Larger practices and practices using outside management companies place more weight on performance-based compensation. However, when more physicians in the group practice the same specialty, less emphasis is placed on performance-based compensation. Finally, the presence of an executive partner has no influence on compensation mix
Association between Resistin Levels and All-Cause and Cardiovascular Mortality: A New Study and a Systematic Review and Meta-Analysis.
CONTEXT: Studies concerning the association between circulating resistin and mortality risk have reported, so far, conflicting results.
OBJECTIVE: To investigate the association between resistin and both all-cause and cardiovascular (CV) mortality risk by 1) analyzing data from the Gargano Heart Study (GHS) prospective design (n=359 patients; 81 and 58 all-cause and CV deaths, respectively); 2) performing meta-analyses of all published studies addressing the above mentioned associations.
DATA SOURCE AND STUDY SELECTION: MEDLINE and Web of Science search of studies reporting hazard ratios (HR) of circulating resistin for all-cause or CV mortality.
DATA EXTRACTION: Performed independently by two investigators, using a standardized data extraction sheet.
DATA SYNTHESIS: In GHS, adjusted HRs per one standard deviation (SD) increment in resistin concentration were 1.28 (95% CI: 1.07-1.54) and 1.32 (95% CI: 1.06-1.64) for all-cause and CV mortality, respectively. The meta-analyses included 7 studies (n=4016; 961 events) for all-cause mortality and 6 studies (n=4,187: 412 events) for CV mortality. Pooled HRs per one SD increment in resistin levels were 1.21 (95% CI: 1.03-1.42, Q-test p for heterogeneity<0.001) and 1.05 (95% CI: 1.01-1.10, Q-test p for heterogeneity=0.199) for all-cause and CV mortality, respectively. At meta-regression analyses, study mean age explained 9.9% of all-cause mortality studies heterogeneity. After adjusting for age, HR for all-cause mortality was 1.24 (95% CI: 1.06-1.45).
CONCLUSIONS: Our results provide evidence for an association between circulating resistin and mortality risk among high-risk patients as are those with diabetes and coronary artery disease
Dynamics of magnetic domain wall motion after nucleation: Dependence on the wall energy
The dynamics of magnetic domain wall motion in the FeNi layer of a
FeNi/Al2O3/Co trilayer has been investigated by a combination of x-ray magnetic
circular dichroism, photoelectron emission microscopy, and a stroboscopic
pump-probe technique. The nucleation of domains and subsequent expansion by
domain wall motion in the FeNi layer during nanosecond-long magnetic field
pulses was observed in the viscous regime up to the Walker limit field. We
attribute an observed delay of domain expansion to the influence of the domain
wall energy that acts against the domain expansion and that plays an important
role when domains are small.Comment: Accepted for publication in Physical Review Letter
Magnetic relaxation of exchange biased (Pt/Co) multilayers studied by time-resolved Kerr microscopy
Magnetization relaxation of exchange biased (Pt/Co)5/Pt/IrMn multilayers with
perpendicular anisotropy was investigated by time-resolved Kerr microscopy.
Magnetization reversal occurs by nucleation and domain wall propagation for
both descending and ascending applied fields, but a much larger nucleation
density is observed for the descending branch, where the field is applied
antiparallel to the exchange bias field direction. These results can be
explained by taking into account the presence of local inhomogeneities of the
exchange bias field.Comment: To appear in Physical Review B (October 2005
Interplay between magnetic anisotropy and interlayer coupling in nanosecond magnetization reversal of spin-valve trilayers
The influence of magnetic anisotropy on nanosecond magnetization reversal in
coupled FeNi/Cu/Co trilayers was studied using a photoelectron emission
microscope combined with x-ray magnetic circular dicroism. In quasi-isotropic
samples the reversal of the soft FeNi layer is determined by domain wall
pinning that leads to the formation of small and irregular domains. In samples
with uniaxial magnetic anisotropy, the domains are larger and the influence of
local interlayer coupling dominates the domain structure and the reversal of
the FeNi layer
Magnetic relaxation measurements of exchange biased (Pt/Co) multilayers with perpendicular anisotropy
Magnetic relaxation measurements were carried out by magneto-optical Kerr
effect on exchange biased (Pt/Co)5/Pt/FeMn multilayers with perpendicular
anisotropy. In these films the coercivity and the exchange bias field vary with
Pt spacer thickness, and have a maximum for 0.2 nm. Hysteresis loops do not
reveal important differences between the reversal for ascending and descending
fields. Relaxation measurements were fitted using Fatuzzo's model, which
assumes that reversal occurs by domain nucleation and domain wall propagation.
For 2 nm thick Pt spacer (no exchange bias) the reversal is dominated by domain
wall propagation starting from a few nucleation centers. For 0.2 nm Pt spacer
(maximum exchange bias) the reversal is strongly dominated by nucleation, and
no differences between the behaviour of the ascending and descending branches
can be observed. For 0.4 nm Pt spacer (weaker exchange bias) the nucleation
density becomes less important, and the measurements reveal a much stronger
density of nucleation centers in the descending branch.Comment: Europhysical Journal B, in print DOI: 10.1140/epjb/e2005-00053-
Magnetization reversal, asymmetry, and role of uncompensated spins in perpendicular exchange coupled systems
This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.Soft x-ray resonant magnetic scattering has been used to investigate the element-selective microscopic magnetization reversal behavior of room temperature perpendicular exchange coupled ferromagnetic∕antiferromagnetic (F∕AF) systems and to study the role of the interfacial coupling strength on it. Different nucleation processes and domain size distributions along the decreasing and increasing branches of the reversal have been found. The size of the magnetic domains during reversal depends on both the F anisotropy and F∕AF coupling strength, decreasing when one of them increases. Evidence of the exchange bias(coercivity enhancement) being induced by pinned (unpinned) uncompensated AF interfacial spins is also shown
Standards for European training requirements in interventional neuroradiology: Guidelines by the Division of Neuroradiology/Section of Radiology European Union of Medical Specialists (UEMS), in cooperation with the Division of Interventional Radiology/UEMS, the European Society of Neuroradiology (ESNR), and the European Society of Minimally Invasive Neurological Therapy (ESMINT)
This document sets out standards for training in Interventional Neuroradiology (INR) in Europe. These standards have been developed by a working group of the European Society of Neuroradiology (ESNR) and the European Society of Minimally Invasive Neurological Therapy (ESMINT) on the initiative and under the umbrella of the Division of Neuroradiology/Section of Radiology of the European Union of Medical Specialists (UEMS)
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