Seesaw Enhancement of Bi-large Mixing in Two-Zero Textures

The seesaw enhancement of the bi-large mixings are discussed for the two-zero textures of the neutrino mass matrix. There are no large mixings in both Dirac neutrino mass matrix $m_D$ and right-handed Majorana neutrino mass matrix $M_R$, however, the bi-large mixing is realized via the seesaw mechanism. We present twelve sets of $m_D$ and $M_R$ for the seesaw enhancement and discuss the related phenomena, the $\mu\to e+\gamma$ process and the leptogenesis. The decay rate of $\mu\to e+\gamma$ is enough suppressed due to zeros in the Dirac neutrino mass matrix. Six $m_D$ lead to the lepton asymmetry, which can explain the baryon number in the universe. Other six $m_D$ are the real matrices, which give no CP asymmetry. Modified Dirac neutrino mass matrices are also discussed.Comment: latex file, 16 page

Strong anisotropic flow in a finely layered asthenosphere

We derive the long wave length equivalents of the constitutive relations for finely stratified fluids as suggested by Saito and Abe [1984]. The results show the transversely isotropic relations characterized by two effective viscosities. One is associated with shear stress applied on the plane parallel to the layering and the other is with normal stress applied perpendicular to the layering. If thin soft layers exist in the low velocity zone, there may be a significant difference in these two viscosities. A simple calculation simulating mantle flow with large apparent anisotropy shows the possible existence of convection having large aspect ratio

Experimental determination and mathematical modeling of standard shapes of forming autophagosomes

オートファゴソーム標準形態の実験的決定と数理モデル --オートファジーを司る膜構造体の形の特徴を実験と理論で解明--. 京都大学プレスリリース. 2024-01-12.The formation of autophagosomes involves dynamic morphological changes of a phagophore from a flat membrane cisterna into a cup-shaped intermediate and a spherical autophagosome. However, the physical mechanism behind these morphological changes remains elusive. Here, we determine the average shapes of phagophores by statistically investigating three-dimensional electron micrographs of more than 100 phagophores. The results show that the cup-shaped structures adopt a characteristic morphology; they are longitudinally elongated, and the rim is catenoidal with an outwardly recurved shape. To understand these characteristic shapes, we establish a theoretical model of the shape of entire phagophores. The model quantitatively reproduces the average morphology and reveals that the characteristic shape of phagophores is primarily determined by the relative size of the open rim to the total surface area. These results suggest that the seemingly complex morphological changes during autophagosome formation follow a stable path determined by elastic bending energy minimization

Cement generations and diagenetic history of the upper Ordovician Cliefden Caves Limestone Group of New South Wales, Australia

Diagenetic features of the upper Ordovician (Caradocian) Cliefden Caves Limestone Group (N. S. W., Australia) were studied by the cathodoluminescence (CL) method, and their relation with depositional environments was discussed. The Cliefden Caves Limestone Group was deposited on a shallow marine carbonate platform developed on a volcanic island. The limestone succession reveals intertidal-subtidal lithofacies and consists of the Fossil Hill, Belubula, and Vandon Limestones, in ascending order. The Fossil Hill Limestone mostly consists of bedded limestone rich in brachiopods and sedentary organisms. The Belubula Limestone is a typical Middle-Upper Ordovician peritidal succession with syn-depositional dolomite and silicified fossil grains. The Vandon Limestone consists of fossiliferous stratified limestone occasionally containing red brown argillaceous limestone beds. The Cliefden Caves Limestone Group was subjected to various diagenetic processes. The investigation of CL is the best or only method to differentiate the diagenetic products. There are at least three cementation stages and a dissolution stage. The cements of the first stage are mainly dull fine-grained (10-30 µm) calcite crystals fringing inter- and intra-granular porosity, which typically indicate a marine phreatic environment. In some specimens of the Belubula Limestone, cement of the first generation exhibits meniscus fabrics suggesting precipitation in a marine vadose environment. The dissolution formed both molds of aragonitic skeletal grains and fabric-unrelated void spaces which can exceed several cm in diameter. Lack of the first generation cement within the dissolution voids indicates that the dissolution postdated the marine cementation. After the dissolution stage, the second cementation precipitated granular calcite crystals composed of non-luminescence, dull, and bright zones in the peripheral order. The relative thickness of non-luminescence and bright zones probably related with a redox condition during their diagenesis. The last generation of cements formed in a deep burial environment, is normally dull and filled almost all remained porosity. This diagenetic history fits to the change of depositional environment which may have been controlled by both of local and global environmental settings

Observation of Microtremors in the Tsukuba Area, Japan, using a Portable Broadband Seismometer

Studies of microtremors have been advanced by different approaches, that is, a variety of observational studies and analyses, for both the short-period and the long-period ranges since the microtremors for each range have their own source and site characteristics in time and space. We, therefore, conducted microtremor observation around Tsukuba City, Ibaraki, Japan, in July and August, 1991, in order to clarify site characteristics of six locations around the Tsukuba Mountain, deploying a portable broadband seismometer (Streckeisen STS-2) in the field of subsurface structure and studying ground motion in both frequency ranges, simultaneously. By a comparison with an STS-1 seismometer, the STS-2 gives reliable frequency ranges higher than 0.09 Hz and 0.05 Hz in horizontal and vertical components, respectively. The correlation of the reference site and the other sites implies that the source of microtremors shares common characteristics for the lower range ( 1 Hz), particularly 1.2 ～ 2.5 Hz, in this area. Three types of dominant peak frequencies for the range of 0.1 ～ 1 Hz are revealed: (1) the peak frequencies ranging from 0.2 to 0.3 Hz observed near Mt.Tsukuba can be explained by the topographic high model of Bard (1982). Two frequency peaks ranging (2) from 0.2 to 0.4 Hz and (3) from 0.5 to 0.8 Hz, observed at the stations on alluvials, are related to any vertical resonance in soft layers, consistent with other geological information. Amplitude ratios at sedimentary sites with respect to TSK (Mt.Tsukuba), a rock site, are greater than unity over 5 Hz where the ratios are reported to be smaller than unity in many areas, which implies relatively hard sedimentary layers in the Tsukuba area

1994 Multi-site Broadband Seismic Observation at Sakurajima Volcano, Japan

Broadband observation of volcanic earthquakes has been recently conducted at many volcanoes. At the Sakurajima Volcano in Japan, one of the most active volcanoes all over the world, we conducted two broadband seismic observations successfully in last three years. However, they left some problems in terms of the number of observation sites and recording systems. This paper reports the outline of our third observation using three broadband seismometers (Streckeisen STS-II) with continuous recording at the Sakurajima Volcano from February 18 to March 28, 1994. This observation is distinguished from the previous two by the three stations operating continuously over the entire period. Although the Sakurajima Volcano had very low seismic activities during this observation period, we observed some kinds of volcanic earthquake, A-type and B-type earthquakes and volcanic tremors, particularly one series of interesting clone events

Hybrid Textures of Neutrinos

We present numerical and comprehensive analyses of the sixty hybrid textures of neutrinos, which have an equality of matrix elements and one zero. These textures are possibly derived from the discrete symmetry. Only six textures among sixty ones are excluded by the present experimental data. Since there are many textures which give similar predictions, the textures are classified based on the numerical results. The neutrinoless double beta decay is also examined in these textures. Our results suggest that there remain still rich structures of the neutrino mass matrix in the phenomenological point of view.Comment: 19 pages, 9 figures; analytical discussions added, table and reference adde