Spin dynamics and quantum tunneling in Fe8 nanomagnet and in AFM rings by NMR

In this thesis, our main interest has been to investigate the spin dynamics and quantum tunneling in single molecule magnets (SMMs). For this we have selected two different classes of SMMs: a ferromagnetic total high spin S = 10 cluster Fe8 and antiferromagnetic (AFM) ring-type clusters. For Fe8, our efforts have been devoted to the investigation of the quantum tunneling of magnetization in the very low temperature region. The most remarkable experimental finding in Fe8 is that the nuclear spin-lattice relaxation rate (1/T1) at low temperatures takes place via strong collision mechanism, and thus it allows to measure directly the tunneling rate vs. T and H for the first time. For AFM rings, we have shown that 1/T1 probes the thermal fluctuations of the magnetization in the intermediate temperature range. We find that the fluctuations are dominated by a single characteristic frequency which has a power-law T-dependence indicative of fluctuations due to electron-acoustic phonon interactions

Brief Review of the Role of Glycogen Synthase Kinase-3β in Amyotrophic Lateral Sclerosis

Glycogen synthase kinase-3β (GSK-3β) is known to affect a diverse range of biological functions controlling gene expression, cellular architecture, and apoptosis. GSK-3β has recently been identified as one of the important pathogenic mechanisms in motor neuronal death related to amyotrophic lateral sclerosis (ALS). Therefore, the development of methods to control GSK-3β could be helpful in postponing the symptom progression of ALS. Here we discuss the known roles of GSK-3β in motor neuronal cell death in ALS and the possibility of employing GSK-3β modulators as a new therapeutic strategy

Changes in Economic Activity, Skills and Inequality in the Service Economy

This paper aims to understand how wage inequality is associated with different level and kind of skills in service economy. Our logic of argument, changes in economic activity and skills in the service economy, is suggested following our observation on changes in skill by examining the International Standard of Industrial Classification of all Economies (ISIC) and the International Standard Classification of Occupations (ISCO). Then we examine how the service sector contributes to total income inequality since the 1980s through conducting a MLD (Mean Logarithmic Deviation) based decomposition analysis with four selected countries, Germany, United States, Sweden and Taiwan, using the Luxembourg Income Study (LIS) Database. Overall, the findings suggest that inequality within the service sector contributes most to total inequality. Among the three skill levels in service sector, inequality within the middle skill level contributed most to the total service sector inequality in all four selected countries

11B^{11}B NMR and Relaxation in MgB2MgB_2 Superconductor

$^{11}B$ NMR and nuclear spin-lattice relaxation rate (NSLR) are reported at 7.2 Tesla and 1.4 Tesla in powder samples of the intermetallic compound $MgB_2$ with superconducting transition temperature in zero field $T_c$ = 39.2 K. From the first order quadrupole perturbed NMR specrum a quadrupole coupling frequency of 835 $\pm$ 5 kHz is obtained. The Knight shift is very small and it decreases to zero in the superconducting phase. The NSLR follows a linear law with $T_1T$ = 165 $\pm$ 10 (sec K) . The results in the normal phase indicate a negligible $s$-character of the wave function of the conduction electrons at the Fermi level. Below $T_c$ the NSLR is strongly field dependent indicating the presence of an important contribution related to the density and the thermal motion of flux lines. No coherence peak is observed at the lower field investigated (1.4 T)

Reproductive ecology of dominant dinoflagellate, Ceratium furca, in the coastal area of Sagami Bay

Reproductive ecology of dinoflagellate, Ceratium furca, was studied in the coastal area of Sagami Bay. Field samplings and laboratory experiments were conducted to investigate seasonal changes of the field population and effects of temperature, salinity and irradiance on the growth rate of C. furca. Abundance of the species increased significantly from April to September and was decreased in November. In particular, the population increased during the spring when the water column was weakly stratified and relatively low nutrient conditions were observed in the surface layer. High growth rates of C. furca were observed at the conditions of 20-28℃, 17-34 PSU and 216-800μEm^s^ with the highest growth rate (μ=0.72d^) being observed at 24℃, 30 PSU and 600μEm^s^. In addition, the growth rates increased gradually with increasing irradiance from 58 to 216μEm^s^ in the all salinity conditions, and afterwards the rates reached plateaus between 216 and 796μEm^s^. The field survey and laboratory experiments indicated that the species is distributed throughout the year and adapted to a wide-range of environmental fluctuations such as water temperature, salinity, irradiance and nutrients. These specific characteristics make C. furca one of the dominant dinoflagellates in the coastal area

Interplay of charge density waves, disorder, and superconductivity in 2H-TaSe2 elucidated by NMR

Single crystals of pristine and 6% Pd-intercalated 2H‐TaSe2 have been studied by means of 77Se nuclear magnetic resonance. The temperature dependence of the 77Se spectrum, with an unexpected line narrowing upon Pd intercalation, unravels the presence of correlated local lattice distortions far above the transition temperature of the charge density wave (CDW) order, thereby supporting a strong-coupling CDW mechanism in 2H‐TaSe2. While, the Knight shift data suggest that the incommensurate CDW transition involves a partial Fermi surface gap opening. As for spin dynamics, the 77Se spin-lattice relaxation rate T1-1 as a function of temperature shows that a pseudogap behavior dominates the low-energy spin excitations even within the CDW phase, and gets stronger along with superconductivity in the Pd-6% sample. We discuss that CDW fluctuations may be responsible for the pseudogap as well as superconductivity, although the two phenomena are unlikely to be directly linked each other