BPS Domain Walls in Models with Flat Directions

We consider BPS domain walls in the four dimensional N=1 supersymmetric models with continuous global symmetry. Since the BPS equation is covariant under the global transformation, the solutions of the BPS walls also have the global symmetry. The moduli space of the supersymmetric vacua in such models have non-compact flat directions, and the complex BPS walls interpolating between two disjoint flat directions can exist. We examine this possibility in two models with global O(2) symmetry, and construct the solution of such BPS walls.Comment: LaTeX file, 19 pages, 8 eps figures, published versio

An Exact Solution of BPS Domain Wall Junction

An exact solution of domain wall junction is obtained in a four-dimensional N=1 supersymmetric U(1) X U(1)' gauge theory with three pairs of chiral superfields which is motivated by the N=2 SU(2) gauge theory with one flavor perturbed by an adjoint scalar mass. The solution allows us to evaluate various quantities including a new central charge Y_k associated with the junction besides Z_k which appears already in domain walls. We find that the new central charge Y_k gives a negative contribution to the mass of the domain wall junction whereas the central charge Z_k gives a dominant positive contribution. One has to be cautious to identify the central charge Y_k alone as the mass of the junction.Comment: LaTeX file, 13 page, 1 ps figur

高次視覚情報処理機能を有する三次元積層人工網膜チップの研究

要約のみTohoku University田中徹課

Geo-Biological Coupling of Authigenic Carbonate Formation and Autotrophic Faunal Colonization at Deep-Sea Methane Seeps I: Geo-Biological Settings

Methane (CH4) in sub-seafloor sediment is generated both biologically and non-biologically from organic and inorganic sources. A major part of the sub-seafloor methane is oxidized before leakage via “anaerobic oxidation of methane” (AOM) in the subsurface. The AOM-survivor methane, which is relatively minor part of the subsurface methane, leaches to the overlying water column and is eventually subject to thorough anaerobic and aerobic oxidation in the water column. The AOM with sulfate results in the generation of carbon dioxide and sulfide; the former (CO2) is incorporated into authigenic carbonate and autotrophic biomass, and the autotrophy is energetically driven by oxidation of the latter (H2S). These processes are typically observed at focused sites that are generally known as “methane seeps” or hydrocarbon seeps, or occasionally called as cold seeps in comparison with hydrothermal vents. Methane seeps are typically formed in passive and active continental margins, occasionally with unique features such as exposed methane hydrates, mud volcanoes, asphalt volcanoes, salt diapirs, and brine pools. Accordingly, authigenic carbonates and unique biological communities are shaped at respective methane seeps. This chapter overviews geological and biological setting for the formation of methane seeps associated with unique landscapes of carbonates and biomes

Refusals Produced by Japanese Learners of English

The present study investigates the production of the speech act of refusal by Japanese learners of English and by native speakers of American English at St. Cloud State University in closed, audio-taped, oral role-plays with an instrument based on the work of Hudson, Detmer, and Brown (1995). Twenty Japanese learners of English and twelve native speakers of English participated. First, the results suggest that having a choice of opting out might have affected the obtained data and increased the validity of this study, especially for Japanese participant groups. There seemed to be some associations between the variables of power, familiarity, affect, age and the opting out choice. Second, some questions of validity arose related to the instrument developed by Hudson et al. Each participant group held different views toward some of the situations used, and individual participants had different perceptions of the degree of influence for each situational variable. Some situations were rated as not likely to happen to participants, illustrating how hard it can be for researchers to design situations relevant to more than one culture. Third, it can be suggested that Japanese learners of English did not produce the same types of responses as native speakers of English in several situations. These findings can be explained by negative pragmatic and linguistic transfer from the Ll to L2. The data suggest that fewer Japanese participants produced no than the American counterparts. Since this study was small-scale and exploratory in nature, the generalizations presented are somewhat constrained. The discussion focuses on issues such as the choice of opting out, research methodology, negative transfer, and cultural stereotypes