A New Approach to Stochastic State selections in Quantum Spin Systems

We propose a new type of Monte Carlo approach in numerical studies of quantum systems. Introducing a probability function which determines whether a state in the vector space survives or not, we can evaluate expectation values of powers of the Hamiltonian from a small portion of the full vector space. This method is free from the negative sign problem because it is not based on importance sampling techniques. In this paper we describe our method and, in order to examine how effective it is, present numerical results on the 4x4, 6x6 and 8x8 Heisenberg spin one-half model. The results indicate that we can perform useful evaluations with limited computer resources. An attempt to estimate the lowest energy eigenvalue is also stated.Comment: 10 pages, 2 figures, 8 table

R&D Status of Nuclear Emulsion For Directional Dark Matter Search

In this study, we are doing R&D for directional dark matter search with nuclear emulsion. First of all, higher resolution nuclear emulsion with fine silver halide crystals was developed in the production facility of emulsion at Nagoya university, and we confirmed that it can detect the expected nuclear recoil tracks. The readout of submicron tracks was required the new technology. We developed the expansion technique, and could readout the signal by shape analysis with optical microscopy. The two dimensional angular resolution is 36 degrees at the original track length of range from 150nm to 200nm with optical microscopy. Finally we demonstrated by using recoiled nuclei induced by 14.8MeV neutron, and confirmed the technique.Moreover, we developed the X-ray microscope system with SPring-8 as final check with higher resolution of selected candidate tracks with optical microscopy. The angular resolution was improved from 31 degrees with optical microscopy to 17degrees with X-ray microscopy at the track length of range from 150nm to 250nm. We are developing the practical system and planning for start of the test running with prototype detector.Comment: Proceedings of the 3rd International conference on Directional Detection of Dark Matter (CYGNUS 2011), Aussois, France, 8-10 June 201

The Measurement of Strength in Children: Is the Peak Value Truly Maximal?

It is unclear whether the measurement of maximum muscle strength in younger children can be performed accurately due to factors such as motivation and maturity (i.e., the ability to receive instruction). If there is a large change in a ratio between muscular strength and size from the youngest to the oldest, then this might provide some indication that the youngest may not have been able to voluntarily activate their muscles for reasons mentioned previously. The purpose of this study was to observe the ratio between handgrip strength (HGS) and forearm muscle thickness (MT) across differing ages in younger children. A total of 1133 preschool children (559 boys and 574 girls) between the ages of 4.5 and 6.5 years had MT and HGS measurements and calculated the ratio of HGS/MT (kg/cm). Linear regression was used to assess the impact of age and sex on the dependent variables of MT, HGS, and the HGS/MT ratio. The HGS/MT ratio increases moderately from age 4.5 to 6.5 in both boys and girls. However, the difference in this ratio was small between the age ranges in this sample. Our results indicate children as young as 4.5 may be accurately measured with the handgrip strength test

Dynamic regulation of Ero1 and peroxiredoxin 4 localization in the secretory pathway

In the early secretory compartment (ESC), a network of chaper- ones and enzymes assists oxidative folding of nascent proteins. Ero1 flavoproteins oxidize protein disulfide isomerase (PDI), gen- erating H2O2 as a byproduct. Peroxiredoxin 4 (Prx4) can utilize luminal H2O2 to oxidize PDI, thus favoring oxidative folding while limiting oxidative stress. Interestingly, neither ER oxidase contains known ER retention signal(s), raising the question of how cells pre- vent their secretion. Here we show that the two proteins share sim- ilar intracellular localization mechanisms. Their secretion is pre- vented by sequential interactions with PDI and ERp44, two resident proteins of the ESC-bearing KDEL-like motifs. PDI binds preferentially Ero1 , whereas ERp44 equally retains Ero1 and Prx4. The different binding properties of Ero1 and Prx4 increase the robustness of ER redox homeostasis