Waseda University

About: Waseda University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Large Hadron Collider & Catalysis. The organization has 24220 authors who have published 46859 publications receiving 837855 citations. The organization is also known as: Waseda daigaku & Sōdai.

Search for massive, long-lived particles using multitrack displaced vertices or displaced lepton pairs in pp collisions at √s = 8 TeV with the ATLAS detector

Abstract: Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at root s = 8 TeV corresponding to an integrated luminosity of 20.3 fb(-1) collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios.

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at $\sqrt{s}=7\TeV$

Abstract: A measurement of the production cross-section for top quark pairs (t (t) over bar) in pp collisions at root s = 7 TeV is presented using data recorded with the ATLAS detector at the Large Hadron Co ...

Dilatonic black holes with a Gauss-Bonnet term

Abstract: We discuss black holes in an effective theory derived from a superstring model, which includes a dilaton field, a gauge field, and the Gauss-Bonnet term. Assuming U(1) or SU(2) symmetry for the gauge field, we find four types of spherically symmetric solutions, i.e., a neutral, an electrically charged, a magnetically charged, and a ``colored'' black hole, and discuss their thermodynamical properties and fate via the Hawking evaporation process. For neutral and electrically charged black holes, we find a critical point and a singular end point. Below the mass corresponding to the critical point, no solution exists, while the curvature on the horizon diverges and a naked singularity appears at the singular point. A cusp structure in the mass-entropy diagram is found at the critical point and black holes on the branch between the critical and singular points become unstable. For magnetically charged and ``colored'' black holes, the solution becomes singular just at the end point with a finite mass. Because the black hole temperature is always finite even at the critical point or the singular point, we may conclude that the evaporation process will not be stopped even at the critical point or the singular point, and the black hole will move to a dynamical evaporation phase or a naked singularity will appear.

A review of technology choice for teaching language skills and areas in the CALL literature

Abstract: The use of technology in language teaching and learning has been the focus of a number of recent research review studies, including developments in technology and CALL research (Zhao, 2003), CALL as an academic discipline (Debski, 2003), ICT effectiveness (Felix, 2005), and subject characteristics in CALL research (Hubbard, 2005), to name a few. Such studies have contributed to clarifying how language learning technologies have been investigated, but questions remain regarding how these technologies have been used in achieving learning objectives. In other words, what technologies do CALL practitioners select for the teaching of a certain language skill or area such as listening, grammar or pronunciation? Are the decisions to use these technologies made on pedagogical grounds, or alternatively, are there other aspects that are more instrumental in influencing what is used in the language classroom? The purpose of this study is to review the literature to examine what technologies are used in the teaching of the language skills and areas. All empirical research articles appearing in four major English-language journals in the field of CALL (CALICO Journal, CALL, Language Learning & Technology, and ReCALL) from 2001 to 2005 were examined and the results collated to determine (1) what types of technologies are being used in the teaching of specific language skills and areas, (2) whether researchers had a clear idea in mind regarding their choice of technology or technologies in relation to their learning objectives, and (3) whether the researchers attempted to capitalise upon the features inherent in the technology or technologies as opposed to traditional, non-CALL means. The paper concludes with a discussion of the relationship between technology and pedagogical goals.

Complex zeolite structure solved by combining powder diffraction and electron microscopy

Abstract: Many industrially important materials are polycrystalline and so most conventional methods to solve crystal structures, which require single crystals, are ineffective. Of the alternatives, transmission electron microscopy has so far solved only simple structures; and in powder diffraction the overlap of peaks with similar diffraction angles causes ambiguities in the intensities. Now, powder diffraction data applied to an algorithm incorporating phase information from high-resolution transmission electron micrographs has provided a way of solving zeolite structures using polycrystalline samples. The new technique has successfully solved the structure of zeolite TNU-9, the most complex zeolite known. Many industrially important materials, ranging from ceramics to catalysts to pharmaceuticals, are polycrystalline and cannot be grown as single crystals. This means that non-conventional methods of structure analysis must be applied to obtain the structural information that is fundamental to the understanding of the properties of these materials. Electron microscopy might appear to be a natural approach, but only relatively simple structures have been solved by this route. Powder diffraction is another obvious option, but the overlap of reflections with similar diffraction angles causes an ambiguity in the relative intensities of those reflections. Various ways of overcoming or circumventing this problem have been developed1,2, and several of these involve incorporating chemical information into the structure determination process3,4,5,6,7. For complex zeolite structures, the FOCUS algorithm8,9 has proved to be effective. Because it operates in both real and reciprocal space, phase information obtained from high-resolution transmission electron microscopy images can be incorporated directly into this algorithm in a simple way. Here we show that by doing so, the complexity limit can be extended much further. The power of this approach has been demonstrated with the solution of the structure of the zeolite TNU-9 (|H9.3|[Al9.3Si182.7O384]; ref. 10) with 24 topologically distinct (Si,Al) atoms and 52 such O atoms. For comparison, ITQ-22 (ref. 11), the most complex zeolite known to date, has 16 topologically distinct (Si,Ge) atoms.