Localized Tachyons and the Quantum McKay Correspondence

The condensation of closed string tachyons localized at the fixed point of a C^d/\Gamma orbifold can be studied in the framework of renormalization group flow in a gauged linear sigma model. The evolution of the Higgs branch along the flow describes a resolution of singularities via the process of tachyon condensation. The study of the fate of D-branes in this process has lead to a notion of a ``quantum McKay correspondence.'' This is a hypothetical correspondence between fractional branes in an orbifold singularity in the ultraviolet with the Coulomb and Higgs branch branes in the infrared. In this paper we present some nontrivial evidence for this correspondence in the case C^2/Z_n by relating the intersection form of fractional branes to that of ``Higgs branch branes,'' the latter being branes which wrap nontrivial cycles in the resolved space.Comment: 25 pages; harvma

The GL(2, C) McKay correspondence

In this paper we show that for any affine complete rational surface singularity the quiver of the reconstruction algebra can be determined combinatorially from the dual graph of the minimal resolution. As a consequence the derived category of the minimal resolution is equivalent to the derived category of an algebra whose quiver is determined by the dual graph. Also, for any finite subgroup G of GL(2,C)GL(2,C), it means that the endomorphism ring of the special CM CC [[x, y]]G-modules can be used to build the dual graph of the minimal resolution of C2/GC2/G, extending McKay’s observation (McKay, Proc Symp Pure Math, 37:183–186, 1980) for finite subgroups of SL(2,C)SL(2,C) to all finite subgroups of GL(2,C)GL(2,C)

To be published in: e2000 Conference Proceedings. Inter- and Intra-Organisational Barriers to Sharing Knowledge in the Extended Supply-Chain

Abstract. This paper aims to describe the main barriers to knowledge sharing in the extended enterprise. The barriers were identified through a literature review and work with industrial companies. The barriers have been categorised according to the TOP (Technology, Organisation, People) classification. The main finding is that th

MAP D-PHASE: real-time demonstration of hydrological ensemble prediction systems

Mesoscale Alpine Programme Demonstration of Probabilistic Hydrological and Atmospheric Simulation of Flood Events (MAP D-PHASE) is a forecast demonstration project aiming at demonstrating recent improvements in the operational use of end-to-end forecasting system consisting of atmospheric models, hydrological prediction systems, nowcasting tools and warnings for end-users. Both deterministic and ensemble prediction systems (EPSs) have been implemented for the European Alps (atmospheric models) and a selection of mesoscale river basins (hydrological models) in Central Europe. A first insight into MAP D-PHASE with focus on operational ensemble hydrological simulations is presented here. Copyright 2008 Royal Meteorological Societ

MAP D-PHASE: real-time demonstration of hydrological ensemble prediction systems

Mesoscale Alpine Programme Demonstration of Probabilistic Hydrological and Atmospheric Simulation of Flood Events (MAP D-PHASE) is a forecast demonstration project aiming at demonstrating recent improvements in the operational use of end-to-end forecasting system consisting of atmospheric models, hydrological prediction systems, nowcasting tools and warnings for end-users. Both deterministic and ensemble prediction systems (EPSs) have been implemented for the European Alps (atmospheric models) and a selection of mesoscale river basins (hydrological models) in Central Europe. A first insight into MAP D-PHASE with focus on operational ensemble hydrological simulations is presented here

MEFFE, satellite and combined satellite-radar techniques in meteorological forecasting for flood events; research activities and results.

The risk management process implies a sequence of: 1) a long term meteorological forecasting (up to 7-10 days, done by Global Circulation Models); 2) a short term forecasting (up to 72 hours, done by Limited Area Models, LAM); 3) a very short term forecasting by observational tools (satellites and radar). A skilled rainfall rate forecast to minimize loss of life and economic damage is therefore important. The MEFFE project was concerted to produce improvements in rainfall intensity estimates for mitigating the risk of flood events using nowcasting techniques (meteorological satellite sensors, combined satellite-radar data and numerical models). The main goal was achieved by: 1) better knowledge of meteorological systems generating different flood events; 2) coupling satellite data, radar data and numerical Limited Area Models; 3) improving MW and VIS-IR algorithms for precipitation retrieval; 4) improving weather numerical models (LAM and Cloud Mesoscale Models) that combine surface and upper air measurements, and radar-satellite data; 5) defining the characteristics of Nowcasting procedures for rainfall rate intensity. The following points were considered: i) climatology of floods in Europe; ii) Rainfall estimates from VIS and IR satellites; iii) Microwave Radiometry; iv) Precipitating Cloud Models and Retrieval Algorithms; v) Short range weather forecasting by Limited Area Model; vi) The individual radar and networks of radars in nowcasting