Geometric Crystals on Flag Varieties and Unipotent Subgroups of Classical Groups

For a classical simple algebraic group $G$ we obtain the affirmative answer for the conjecture in [8] that there exists an isomorphism between the geometric crystal on the flag variety and the one on the unipotent subgroup $U^-$.Comment: Latex, 21page

BIMA Array Observations of the Highly Unusual SiO Maser Source with a Bipolar Nebulosity, IRAS 19312+1950

We report the results of mapping observations of the bipolar nebula with SiO maser emission, IRAS 19312+1950, in the CO (J=1-0 and J=2-1), 13CO (J=1-0 and J=2-1), C18O (J=1-0), CS (J=2-1), SO (J_K=3_2-2_1) and HCO+ (J=3-2) lines with the Berkeley-Illinois-Maryland Association array. Evolutional status of this source has been evoking a controversy since its discovery, though SiO maser sources are usually identified as late-type stars with active mass loss. In line profiles, two kinematical components are found as reported in previous single-dish observations: a broad pedestal component and a narrow component. Spatio-kinetic properties of a broad component region traced by 12CO lines are roughly explained by a simple spherical outflow model with a typical expanding velocity of an AGB star, though some properties of the broad component region still conflict with properties of a typical AGB spherical outflow. A narrow component region apparently exhibits a bipolar flow. The angular size of the narrow component region is spatially larger than that of a broad component region. Intensity distribution of the CS emission avoids the central region of the source, and that of an SO broad component emission exhibits a small feature peaked exactly at the mapping center. According to the present results, if a broad component really originates in a spherical outflow, an oxygen-rich evolved stellar object seems to be a natural interpretation for the central star of IRAS 19312+1950.Comment: 27 pages, 11 figures; accepted for publication in Ap

A representation theorem on a filtering model with first-passage-type stopping time

We present a representation theorem for a filtering model with first-passage-type stopping time. The model is constructed from two unobservable processes and one observable process that is under the influence of two unobservable processes.A filter is constructed using Brownian motion in the observable process and a first-passage-type stopping time in an unobservable process.Though our theorems are similar to those of Nakagawa\cite{Nakagawa}, we do not use pinned Brownian motion measure, which is difficult to deal with. In addition, we describe a representation theorem for another filtration that was not discussed by Nakagaw

Antitumor factors of draining lymph node cells of the mouse sensitized with ehrlich ascites tumor cells. I. Antitumor effect of subcellular factor

The regional lymph node cells of the mice sensitized with Ehrlich ascites tumor cells is known to possess a substance that shows antitumor activity on target cells (JTC-II cells). For the purpose to clarify the localization of this substance the regional lymph node cells from such sensitized mice were treated with trypsin solution of different concentrations (1.0 %, 0.2 %, and 0.01 %), and the tissue culture was carried out with JTC.II cells. As a result it was found that these lymph node cells lost antitumor activity. Next, by the differential contrifugation of these sensitized lymphocytes we obtained F1 fraction (700 g, sediment), F2 (8,500 g sediment), F3 (100,000 g sediment) and F4 (100,000 g supernatant). In the presence of each of these fractions tissue culture was conducted with JTC-II cells as target cells, and it was found that the substance with antitumor activity is contained abundantly in F2 fraction (8,500 g sediment) and F4 fraction (100,000 g supernatant). After giving due consideration to the results of these two experiments and also to the available data in the literature, we assume that the substance with antitumor activity is contained in the cell membrane component.</p