611 research outputs found
Linear-response theory of spin Seebeck effect in ferromagnetic insulators
We formulate a linear response theory of the spin Seebeck effect, i.e., a
spin voltage generation from heat current flowing in a ferromagnet. Our
approach focuses on the collective magnetic excitation of spins, i.e., magnons.
We show that the linear-response formulation provides us with a qualitative as
well as quantitative understanding of the spin Seebeck effect observed in a
prototypical magnet, yttrium iron garnet.Comment: 6 pages, 3 figures. Added references and revised argument on the
length scales at the end of Sec.
Mesoscopic Stern-Gerlach spin filter by nonuniform spin-orbit interaction
A novel spin filtering in two-dimensional electron system with nonuniform
spin-orbit interactions (SOI) is theoretically studied. The strength of SOI is
modulated perpendicular to the charge current. A spatial gradient of effective
magnetic field due to the nonuniform SOI causes the Stern-Gerlach type spin
separation. The direction of the polarization is perpendicular to the current
and parallel to the spatial gradient. Almost 100 % spin polarization can be
realized even without applying any external magnetic fields and without
attaching ferromagnetic contacts. The spin polarization persists even in the
presence of randomness.Comment: 6 pages, 5 figures (2 color figures), to appear in Phys. Rev. B,
Rapid Commu
Electrocardiographic Parameters and Fatal Arrhythmic Events in Patients With Brugada Syndrome
Objectives This study aimed to determine the usefulness of the combination of several electrocardiographic markers on risk assessment of ventricular fibrillation (VF) in patients with Brugada syndrome (BrS).
Background Detection of high-/low-risk BrS patients using a noninvasive method is an important issue in the clinical setting. Several electrocardiographic markers related to depolarization and repolarization abnormalities have been reported, but the relationship and usefulness of these parameters in VF events are unclear.
Methods Baseline characteristics of 246 consecutive patients (236 men; mean age, 47.6 +/- 13.6 years) with a Brugada-type electrocardiogram, including 13 patients with a history of VF and 40 patients with a history of syncope episodes, were retrospectively analyzed. During the mean follow-up period of 45.1 months, VF in 23 patients and sudden cardiac death (SCD) in 1 patient were observed. Clinical/ genetic and electrocardiographic parameters were compared with VF/SCD events.
Results On univariate analysis, a history of VF and syncope episodes, paroxysmal atrial fibrillation, spontaneous type 1 pattern in the precordial leads, and electrocardiographic markers of depolarization abnormalities (QRS duration >= 120 ms, and fragmented QRS [f-QRS]) and those of repolarization abnormalities (inferolateral early repolarization [ER] pattern and QT prolongation) were associated with later cardiac events. On multivariable analysis, a history of VF and syncope episodes, inferolateral ER pattern, and f-QRS were independent predictors of documented VF and SCD (odds ratios: 19.61, 28.57, 2.87, and 5.21, respectively; p < 0.05). Kaplan-Meier curves showed that the presence/ absence of inferolateral ER and f-QRS predicted a worse/better prognosis (log-rank test, p < 0.01).
Conclusions The combination of depolarization and repolarization abnormalities in BrS is associated with later VF events. The combination of these abnormalities is useful for detecting high-and low-risk BrS patients
Charge and Spin Currents Generated by Dynamical Spins
We demonstrate theoretically that a charge current and a spin current are
generated by spin dynamics in the presence of spin-orbit interaction in the
perturbative regime. We consider a general spin-orbit interaction including the
spatially inhomogeneous case. Spin current due to spin damping is identified as
one origin of generated charge current, but other contributions exist, such as
the one due to an induced conservative field and the one arising from the
inhomogeneity of spin-orbit interaction.Comment: 14 pages, 4 figure
Perturbation theory of the dynamic inverse spin Hall effect with charge conservation
We present gauge-invariant theory of the dynamic inverse spin Hall effect
driven by the spin--orbit interaction in metallic systems. Charge conservation
is imposed diagrammatically by including vertex corrections. We show the charge
current is induced by an effective electric field that is proportional to the
spin current pumped by the magnetization dynamics. The result is consistent
with recent experiments.Comment: 16pages, 5figure
Impact of childhood experiences on the development of entrepreneurial intentions
Fostering entrepreneurship and an entrepreneurial culture has become a key policy priority for governments. To encourage entrepreneurship and an entrepreneurial culture, however, there is a need to understand the factors that influence and shape individuals' intentions to start a business. This study extends models of entrepreneurial intentions by investigating the influence of various childhood-experience factors on the perceived feasibility and desirability of starting a business. A structured questionnaire was completed by over 1,000 university students and analysed using regression analysis. Results indicated that perceptions of entrepreneurship were influenced not only by parental ownership of a business, but also by a difficult childhood and frequent relocation
- …