Transport properties of diluted magnetic semiconductors: Dynamical mean field theory and Boltzmann theory

The transport properties of diluted magnetic semiconductors (DMS) are calculated using dynamical mean field theory (DMFT) and Boltzmann transport theory. Within DMFT we study the density of states and the dc-resistivity, which are strongly parameter dependent such as temperature, doping, density of the carriers, and the strength of the carrier-local impurity spin exchange coupling. Characteristic qualitative features are found distinguishing weak, intermediate, and strong carrier-spin coupling and allowing quantitative determination of important parameters defining the underlying ferromagnetic mechanism. We find that spin-disorder scattering, formation of bound state, and the population of the minority spin band are all operational in DMFT in different parameter range. We also develop a complementary Boltzmann transport theory for scattering by screened ionized impurities. The difference in the screening properties between paramagnetic ($T>T_c$) and ferromagnetic ($T<T_c$) states gives rise to the temperature dependence (increase or decrease) of resistivity, depending on the carrier density, as the system goes from the paramagnetic phase to the ferromagnetic phase. The metallic behavior below $T_c$ for optimally doped DMS samples can be explained in the Boltzmann theory by temperature dependent screening and thermal change of carrier spin polarization.Comment: 15 pages, 15 figure

Local magnetic anisotropy in BaFe2_2As2_2: a polarized inelastic neutron scattering study

The anisotropy of the magnetic excitations in BaFe$_2$As$_2$ was studied by polarized inelastic neutron scattering which allows one to separate the components of the magnetic response. Despite the in-plane orientation of the static ordered moment we find the in-plane polarized magnons to exhibit a larger gap than the out-of-plane polarized ones indicating very strong single-ion anisotropy within the layers. It costs more energy to rotate a spin within the orthorhombic {\it a-b} plane than rotating it perpendicular to the FeAs layers.Comment: 4 pages, 4 figure

Numerical analysis of tsunami-induced inundation behind building along coasts

To evaluate the effects of impermeable rigid buildings located near vertical quay walls on the reduction of the inundation water volumes due to run-up tsunamis, a full-scale three-dimensional numerical analysis is performed using a three-dimensional coupled fluid-structure-sediment interaction model. Numerical results show that the inundation water volume can be reduced with an increase in the shielding ratio of the long-shore width of the buildings with respect to the total width of the coastline, and accordingly the buildings located along the coasts have the reduction effects of the inundation water volume. This suggests that countermeasures against tsunamis can be evaluated in a\ud comprehensive manner in terms of not only shore protection facilities for tsunamis at relatively high frequencies but also such buildings. Furthermore, the inundation depth at the seaward side of the buildings and the cross-shore bottom flow velocity at the gaps between the buildings increase with the shielding ratio, suggesting an increase in tsunami force and the onset of local scouring when the shielding ratio is large. Consequently, when designing buildings along the coasts, it is essential to consider an appropriate balance between the reduction effects of the inundation water volume and the instability of the buildings caused by the tsunami force and the local scouring

Limits to in vivo fate changes of epithelia in thymus and parathyroid by ectopic expression of transcription factors Gcm2 and Foxn1

The development of the parathyroid and the thymus from the third pharyngeal pouch depends on the activities of the Gcm2 and Foxn1 transcription factors, respectively, whose expression domains sharply demarcate two regions in the developing third pharyngeal pouch. Here, we have generated novel mouse models to examine whether ectopic co-expression of Gcm2 in the thymic epithelium and of Foxn1 in the parathyroid perturbs the establishment of organ fates in vivo. Expression of Gcm2 in the thymic rudiment does not activate a parathyroid-specific expression programme, even in the absence of Foxn1 activity. Co-expression of Foxn1 in the parathyroid fails to impose thymopoietic capacity. We conclude that the actions of Foxn1 and Gcm2 transcription factors are cell context-dependent and that they each require permissive transcription factor landscapes in order to successfully interfere with organ-specific cell fate

Spin dynamics of a one-dimensional spin-1/2 fully anisotropic Ising-like antiferromagnet in a transverse magnetic field

We consider the one-dimensional Ising-like fully anisotropic S=1/2 Heisenberg antiferromagnetic Hamiltonian and study the dynamics of domain wall excitations in the presence of transverse magnetic field $h_x$. We obtain dynamical spin correlation functions along the magnetic field $S^{xx}(q,\omega)$ and perpendicular to it $S^{yy}(q,\omega)$. It is shown that the line shapes of $S^{xx}(q,\omega)$ and $S^{yy}(q,\omega)$ are purely symmetric at the zone-boundary. It is observed in $S^{yy}(q,\omega)$ for $\pi/2<q<\pi$ that the spectral weight moves toward low energy side with the increase of $h_x$. This model is applicable to study the spin dynamics of CsCoCl$_3$ in the presence of weak interchain interactions.Comment: 19 pages, LaTeX, 12 eps figure

Varietal differences in the texture of grape berries measured by penetration tests

Penetration tests were made on 8 mm thick flesh sections from grape berries of 22 cultivars of Vitis vinifera L. and 18 of Vitis labruscana Bailey. Deformation at the first major peak (DFP), maximum force (MF), force at the first major peak (FFP) and work to the first major peak (WFP) were recorded. High correlation coefficients were obtained between the rating of difficulty of breakdown on mastication in the sensory tests and DFP (r=0.86**), and the rating of flesh firmness in the sensory test and MF (r=0.84**). The mean value and variance of DFP and WFP were significantly higher in V. labruscana than in V. vinifera, whereas those of MF were nearly the same. DFP and MF were not correlated for V. vinifera cultivars, but were for V. labruscana cultivars (r=0.68**). These results indicate that the texture of V. labruscana had a wide variation in toughness whereas that of V. vinifera was brittle and did not have a wide variation in toughness; both groups had the same variation in firmness

Study of Magnetic Excitation in Singlet-Ground-State Magnets CsFeCl3_3 and RbFeCl3_3 by Nuclear Magnetic Relaxation

The temperature dependences of spin-lattice relaxation time $T_1$ of $^{133}$Cs in CsFeCl$_3$ and $^{87}$Rb in RbFeCl$_3$ were measured in the temperature range between 1.5 K and 22 K, at various fields up to 7 T applied parallel (or perpendicular) to the c-axis, and the analysis was made on the basis of the DCEFA. The mechanism of the nuclear magnetic relaxation is interpreted in terms of the magnetic fluctuations which are characterized by the singlet ground state system. In the field region where the phase transition occurs, $T_1^{-1}$ exhibited the tendency of divergence near $T_{\rm N}$, and this feature was ascribed to the transverse spin fluctuation associated with the mode softening at the $K$-point. It was found that the damping constant of the soft mode is remarkably affected by the occurrence of the magnetic ordering at lower temperature, and increases largely in the field region where the phase transition occurs.Comment: 12 pages, 18 figures, submitted to J. Phys. Soc. Jp

The Morphological Changes in the Vestibular Sensory Epithelia Following Electrical Stimulation

The morphological changes of the vestibular sensory epithelia of the guinea pig following electrical stimulation were investigated using scanning electron microscope. Positive and negative square wave pulse stimulation was given through a silver ball electrode placed on the round window membrane for one hour. The current intensities used were 100, 200 and 300 A. While the direct current stimulation at intensities of 100 or 200 A did not cause any significant changes, severe damage of the utricular macula and the ampullar crista of the lateral semicircular canal was observed at 300 A. The degenerative changes such as fusion of sensory hairs, protrusion of the cuticular plate and loss of sensory cells were found on both the utricle and the semicircular canal. In the most severely damaged area, the sensory epithelial surface was badly torn apart. In the clinical application of direct current to the inner ear for relieving tinnitus, special attention should be paid to the vestibular organ

Presentations of major peripheral arterial disease and risk of major outcomes in patients with type 2 diabetes: results from the ADVANCE-ON study.

BACKGROUND: Peripheral arterial disease (PAD) is known to be associated with high cardiovascular risk, but the individual impact of PAD presentations on risk of macrovascular and microvascular events has not been reliably compared in patients with type 2 diabetes. We aimed to evaluate the impact of major PAD, and its different presentations, on the 10-year risk of death, major macrovascular events, and major clinical microvascular events in these patients. METHODS: Participants in the action in diabetes and vascular disease: PreterAx and DiamicroN modified-release controlled evaluation (ADVANCE) trial and the ADVANCE-ON post-trial study were followed for a median of 5.0 (in-trial), 5.4 (post-trial), and 9.9 (overall) years. Major PAD at baseline was subdivided into lower-extremity chronic ulceration or amputation secondary to vascular disease and history of peripheral revascularization by angioplasty or surgery. RESULTS: Among 11,140 participants, 516 (4.6 %) had major PAD at baseline: 300 (2.7 %) had lower-extremity ulceration or amputation alone, 190 (1.7 %) had peripheral revascularization alone, and 26 (0.2 %) had both presentations. All-cause mortality, major macrovascular events, and major clinical microvascular events occurred in 2265 (20.3 %), 2166 (19.4 %), and 807 (7.2 %) participants, respectively. Compared to those without PAD, patients with major PAD had increased rates of all-cause mortality (HR 1.35, 95 % CI 1.15-1.60, p = 0.0004), and major macrovascular events (1.47 [1.23-1.75], p < 0.0001), after multiple adjustments for region of origin, cardiovascular risk factors and treatments, peripheral neuropathy markers, and randomized treatments. We have also observed a trend toward an association of baseline PAD with risk of major clinical microvascular events [1.31 (0.96-1.78), p = 0.09]. These associations were comparable for patients with a lower-extremity ulceration or amputation and for those with a history of peripheral revascularization. Furthermore, the risk of retinal photocoagulation or blindness, but not renal events, increased in patients with lower-extremity ulceration or amputation [1.53 (1.01-2.30), p = 0.04]. CONCLUSIONS: Lower-extremity ulceration or amputation, and peripheral revascularization both increased the risks of death and cardiovascular events, but only lower-extremity ulceration or amputation increased the risk of severe retinopathy in patients with type 2 diabetes. Screening for major PAD and its management remain crucial for cardiovascular prevention in patients with type 2 diabetes (ClinicalTrials.gov number, NCT00949286)

Morphological Changes in the Vestibular Epithelia and Ganglion Induced by Ototoxic Drug

The morphological changes of the vestibular sensory epithelia and the vestibular ganglions induced by Gentamicin (GM) were investigated using scanning electron microscope, transmission electron microscope and light microscope. The guinea pigs were injected with a single application of 4 mg (0.1ml) of GM into the middle ear through the tympanic membrane. The vestibular organs and the ganglions were observed up to 6 months after the treatment. Four days after the injection, fused, ballooned and missing cilia were observed in the vestibular sensory epithelia. These changes progressed and extended toward the periphery of the crista and the macula. The changes of the vestibular ganglions were first observed one month after the treatment. The degenerative process started from destruction of the mitochondrial cristae and vacuolization of the cytoplasm in the Schwann cell. The next step of the change was dissociation of the myelin sheath around the ganglion cell. The cytoplasmic organelles in the ganglion cell gradually deteriorated. At the later stage, the myelin sheath around the ganglion cell disappeared and the number of the cell reduced. Furthermore, the myelin sheath of the nerve fiber was dissociated. In this study the signs of the vestibular ganglion damage were later than that of the vestibular organ. However, we thought the changes in the ganglion are probably due to direct influence of GM, since the degeneration was found to develop in a relatively short period