Supersymmetric extension of Moyal algebra and its application to the matrix model

We construct operator representation of Moyal algebra in the presence of fermionic fields. The result is used to describe the matrix model in Moyal formalism, that treat gauge degrees of freedom and outer degrees of freedom equally.Comment: to appear in Mod.Phys.Let

Threshold corrections to the radiative breaking of electroweak symmetry and neutralino dark matter in supersymmetric seesaw model

We study the radiative electroweak symmetry breaking and the relic abundance of neutralino dark matter in the supersymmetric type I seesaw model. In this model, there exist threshold corrections to Higgs bilinear terms coming from heavy singlet sneutrino loops, which make the soft supersymmetry breaking (SSB) mass for up-type Higgs shift at the seesaw scale and thus a minimization condition for the Higgs potential is affected. We show that the required fine-tuning between the Higgsino mass parameter mu and the SSB mass for up-type Higgs may be reduced at the electroweak scale, due to the threshold corrections. We also present how the parameter mu depends on the SSB B-parameter for heavy singlet sneutrinos. Since the property of neutralino dark matter is quite sensitive to the size of mu, we discuss how the relic abundance of neutralino dark matter is affected by the SSB B-parameter. Taking the SSB B-parameter of order of a few hundreds TeV, the required relic abundance of neutralino dark matter can be correctly achieved. In this case, dark matter is a mixture of bino and Higgsino, under the condition that gaugino masses are universal at the grand unification scale.Comment: 27 pages, 3 figures; references added, discussion about RGEs added, the version published on PR

Investigation of Microstructure of Cementitious Materials Exposed to High Temperature by Non-destructive Integrated CT-XRD Method

Severe accident occurred in 2011 at the Fukushima Daiichi nuclear power plant and it can be assumed that the concrete building was exposed to high temperatures environment for a long time due to loss of the cooling function of the nuclear reactor. In order to prepare for the best scenario in the decommission plan, it should be first needed to clarify and evaluate the level of damage and deterioration of the contaminated concrete. To solve this problem, experiments were conducted for cementitious materials with the maximum temperature of 400 or 1000 degrees Celsius with durations of up to 2 hours. Subsequent results were evaluated microscopically. In this research, authors have employed a Non-Destructive Integrated CT-XRD Method using synchrotron white X-ray. The unique feature of this method is that both CT for measuring internal structure and XRD for identifying crystal structure can be performed on the same specimen at the same time. Therefore, in addition to other measurements such as the Thin film X-ray diffraction technique, the application of this method is expected to bring an interesting exploration with regard to the physical and chemical alteration of the concrete that was endured by high temperatures

Computational cell model based on autonomous cell movement regulated by cell-cell signalling successfully recapitulates the "inside and outside" pattern of cell sorting

<p>Abstract</p> <p>Background</p> <p>Development of multicellular organisms proceeds from a single fertilized egg as the combined effect of countless numbers of cellular interactions among highly dynamic cells. Since at least a reminiscent pattern of morphogenesis can be recapitulated in a reproducible manner in reaggregation cultures of dissociated embryonic cells, which is known as cell sorting, the cells themselves must possess some autonomous cell behaviors that assure specific and reproducible self-organization. Understanding of this self-organized dynamics of heterogeneous cell population seems to require some novel approaches so that the approaches bridge a gap between molecular events and morphogenesis in developmental and cell biology. A conceptual cell model in a computer may answer that purpose. We constructed a dynamical cell model based on autonomous cell behaviors, including cell shape, growth, division, adhesion, transformation, and motility as well as cell-cell signaling. The model gives some insights about what cellular behaviors make an appropriate global pattern of the cell population.</p> <p>Results</p> <p>We applied the model to "inside and outside" pattern of cell-sorting, in which two different embryonic cell types within a randomly mixed aggregate are sorted so that one cell type tends to gather in the central region of the aggregate and the other cell type surrounds the first cell type. Our model can modify the above cell behaviors by varying parameters related to them. We explored various parameter sets with which the "inside and outside" pattern could be achieved. The simulation results suggested that direction of cell movement responding to its neighborhood and the cell's mobility are important for this specific rearrangement.</p> <p>Conclusion</p> <p>We constructed an <it>in silico </it>cell model that mimics autonomous cell behaviors and applied it to cell sorting, which is a simple and appropriate phenomenon exhibiting self-organization of cell population. The model could predict directional cell movement and its mobility are important in the "inside and outside" pattern of cell sorting. Those behaviors are altered by signal molecules and consequently affect the global pattern of the cell sorting. Our model is also applicable to other developmental processes beyond cell sorting.</p