Instrumental Resolution of the Chopper Spectrometer 4SEASONS Evaluated by Monte Carlo Simulation

We performed simulations of the resolution function of the 4SEASONS spectrometer at J-PARC by using the Monte Carlo simulation package McStas. The simulations showed reasonably good agreement with analytical calculations of energy and momentum resolutions by using a simplified description. We implemented new functionalities in Utsusemi, the standard data analysis tool used in 4SEASONS, to enable visualization of the simulated resolution function and predict its shape for specific experimental configurations.Comment: 8 pages, 5 figure

Impact of Environmental Enrichment on Adult Hippocampal Neurogenesis in a Preclinical Mouse Model of Fetal Alcohol Spectrum Disorder (FASD)

Alcohol is a potent teratogen to the developing CNS, and moderate-heavy alcohol intake during pregnancy causes fetal alcohol syndrome (FAS) and fetal alcohol spectrum disorder (FASD). These patients display CNS symptoms associated with developmental deficits, cognitive impairment and social abnormalities, with structural impairments in several brain regions. In this dissertation, we investigated the role of FASD in neurogenic functional deficits in the adult hippocampal dentate gyrus. The dentate gyrus is a subregion of the hippocampus that displays unique plasticity, in that new dentate granule neurons are continuously produced throughout life. Adult hippocampal neurogenesis is thought to play key roles in pattern separation and associative learning and in depression-like behaviors. Interestingly, adult neurogenesis is stimulated by physical and social enrichment (enriched environments) and learning. It is becoming increasingly apparent that prenatal alcohol exposure produces long-lasting impairments in postnatal hippocampal neurogenesis and learning impairment. My dissertation research addressed the hypothesis that prenatal alcohol exposure (FASD) impairs the EE-mediated survival and electrophysiological properties of newborn DGCs in the adult hippocampus. Utilizing a combination of histological, behavioral and electrophysiological approaches, we addressed the following specific aims Specific Aim 1: To determine whether prenatal alcohol (FASD) impairs the neurogenic response to environmental enrichment in adult Nestin:CreERT2:YFP bitransgenic mice; and if so, to delineate the stage of neural stem cell lineage most impacted by prenatal alcohol exposure. Specific Aim 2: To determine whether adult-generated DGCs in FASD mice display normal electrophysiological properties after developing under standard and enriched conditions. Specific Aim 3: To determine whether adult-generated DGCs in FASD mice display dendritic morphological plasticity in response to enriched environment. My overall findings indicate that FASD severely impairs the late-stage survival of adult-generated DGCs and disrupts the electrophysiological response to EE in the existing granule cell layer, and that this is accompanied by heightened excitatory synaptic transmission in surviving DGCs. These findings suggest that FASD imparts resistance to the full benefits of social and physical enrichment therapies through both impairment of neurogenic and GCL circuitry mechanisms

Ferromagnetic insulating phase in Pr{1-x}Ca{x}MnO3

A ferromagnetic insulating (FM-I) state in Pr0.75Ca0.25MnO3 has been studied by neutron scattering experiment and theoretical calculation. The insulating behavior is robust against an external magnetic field, and is ascribed to neither the phase separation between a ferromagnetic metallic (FM-M) phase and a non-ferromagnetic insulating one, nor the charge ordering. We found that the Jahn-Teller type lattice distortion is much weaker than PrMnO3 and the magnetic interaction is almost isotropic. These features resembles the ferromagnetic metallic state of manganites, but the spin exchange interaction J is much reduced compared to the FM-M state. The theoretical calculation based on the staggered type orbital order well reproduces several features of the spin and orbital state in the FM-I phase.Comment: REVTeX4, 10 pages, 9 figure

DEVELOPMENT OF AERODYNAMICS SIMULATION FRAMEWORK FOR SKI- JUMPING

The purpose of this study was to construct a simulation framework for predicting unsteady aerodynamic characteristics in ski jumping competition. Here, we focused on from takeoffs to the early flight phase in which transient characteristics are expected to greatly affect the distance traveled. For the purpose of applying the developed framework to actual competition, the posture change was reconstructed from the sagittal plane obtained from the video image and simulation was performed. Moreover, in order to examine the validity of the result, it is compared with the simulation result obtained from the three-dimensional motion measured by the motion capture at the same time. In fluid simulation, we developed a finite volume method based on a hierarchical Cartesian grid for the purpose of reproducing complicated posture changes and obtaining results at high speed

Effects of Citric Acid and l-Carnitine on Physical Fatigue

We examined the effects of citric acid and l-carnitine administration on physical fatigue. In a double-blind, placebo-controlled, 3-way crossover study, 18 healthy volunteers were randomized to oral citric acid (2,700 mg/day), l-carnitine (1,000 mg/day), or placebo for 8 days. The fatigue-inducing physical task consisted of workload trials on a cycle ergometer at fixed workloads for 2 h on 2 occasions. Before the physical load, salivary chromogranin A, measured as a physiological stress marker, was lower in the group given citric acid than in the group given placebo. Also, after the physical load, the subjective feeling of fatigue assessed with a visual analogue scale was lower in the citric acid group than in the placebo group. In contrast, l-carnitine had no effect on chromogranin A or subjective fatigue. These results suggest that citric acid reduces physiological stress and attenuates physical fatigue, whereas l-carnitine does not

Ordering Process and Its Hole Concentration Dependence of the Stripe Order in La{2-x}Sr{x}NiO{4}

Ordering process of stripe order in La{2-x}Sr{x}NiO{4} with x being around 1/3 was investigated by neutron diffraction experiments. When the stripe order is formed at high temperature, incommensurability \epsilon of the stripe order has a tendency to show the value close to 1/3 for the samples with x at both sides of 1/3. With decreasing temperature, however, \epsilon becomes close to the value determined by the linear relation of \epsilon = n_h, where n_h is a hole concentration. This variation of the \epsilon strongly affects the character of the stripe order through the change of the carrier densities in stripes and antiferromagnetic domains.Comment: 5 pages, 3 figures, REVTeX, to be published in Phys. Rev.

Novel stripe-type charge ordering in the metallic A-type antiferromagnet Pr{0.5}Sr{0.5}MnO{3}

We demonstrate that an A-type antiferromagnetic (AFM) state of Pr{0.5}Sr{0.5}MnO{3} exhibits a novel charge ordering which governs the transport property. This charge ordering is stripe-like, being characterized by a wave vector q ~ (0,0,0.3) with very anisotropic correlation parallel and perpendicular to the stripe direction. This charge ordering is specific to the manganites with relatively wide one-electron band width (W) which often exhibit a metallic A-type AFM state, and should be strictly distinguished from the CE-type checkerboard-like charge ordering which is commonly observed in manganites with narrower W such as La{1-x}Ca{x}MnO{3} and Pr{1-x}Ca{x}MnO{3}.Comment: REVTeX4, 5 pages, 4 figure