Homogeneous Lorentzian manifolds of a semisimple group

We describe the structure of $d$-dimensional homogeneous Lorentzian $G$-manifolds $M=G/H$ of a semisimple Lie group $G$. Due to a result by N. Kowalsky, it is sufficient to consider the case when the group $G$ acts properly, that is the stabilizer $H$ is compact. Then any homogeneous space $G/\bar H$ with a smaller group $\bar H \subset H$ admits an invariant Lorentzian metric. A homogeneous manifold $G/H$ with a connected compact stabilizer $H$ is called a minimal admissible manifold if it admits an invariant Lorentzian metric, but no homogeneous $G$-manifold $G/\tilde H$ with a larger connected compact stabilizer $\tilde H \supset H$ admits such a metric. We give a description of minimal homogeneous Lorentzian $n$-dimensional $G$-manifolds $M = G/H$ of a simple (compact or noncompact) Lie group $G$. For $n \leq 11$, we obtain a list of all such manifolds $M$ and describe invariant Lorentzian metrics on $M$

Fermionic topological charge of families of lattice gauge fields

Topological charge of families of lattice gauge fields is defined fermionically via families index theory for the overlap Dirac operator. Certain obstructions to gauge invariance of the overlap chiral fermion determinant, as well as the lattice analogues of certain obstructions to gauge fixings without the Gribov problem, have natural descriptions in this context.Comment: 4p., Lattice2002(chiral) (+ one paragraph not included in the proceedings version for length reasons

Jet Studies in STAR via Di-jet Triggered (2+1) Multi-hadron Correlations

We explore jet-medium interactions via the recently developed multi-hadron correlation or "2+1" technique. We restrict the di-jet kinematics by selecting a pair of approximately back-to-back high pT hadron triggers and study associated particles. Here we present our study of di-jet systematics comparing the measurements of associate yields and spectra in 200 GeV Au+Au and d+Au collisions in two different scenarios. We present Sum(pT) as an estimate for energy loss. First findings indicate little to no energy loss in the symmetric "2+1" scenario whereas model predictions are about 2 GeV.Comment: 4 pages, 3 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

The RHIC azimuth quadrupole: "perfect liquid" or gluonic radiation?

Large elliptic flow at RHIC seems to indicate that ideal hydrodynamics provides a good description of Au-Au collisions, at least at the maximum RHIC energy. The medium formed has been interpreted as a nearly perfect (low-viscosity) liquid, and connections have been made to gravitation through string theory. Recently, claimed observations of large flow fluctuations comparable to participant eccentricity fluctuations seem to confirm the ideal hydro scenario. However, determination of the azimuth quadrupole with 2D angular autocorrelations, which accurately distinguish ``flow'' (quadrupole) from ``nonflow'' (minijets), contradicts conventional interpretations. Centrality trends may depend only on the initial parton geometry, and methods used to isolate flow fluctuations are sensitive instead mainly to minijet correlations. The results presented in this paper suggest that the azimuth quadrupole may be a manifestation of gluonic multipole radiation.Comment: 11 pages, 6 figure

Citizenship education, truth and learning : some thoughts on professional deliberation

Through consideration of a classroom context observed as part of a PGCE student teacher’s professional development, reading as a learning activity is considered. It is proposed that ‘learning to read’ engages pupils in a critical social-cultural-political project. Through further analysis of a pupil response identified as ‘wrong’, learning in citizenship education is considered through the prism of realist and constructivist perspectives. Finally, current educational ‘good practice’ is identified as offering more than just ‘things to do in the classroom’; aspects are shown to be concordant with elements of constructivist thinking, thinking which potentially offers professionals a prism through which to examine practise. In short, this paper does not propose that teachers ‘become’ constructivist in orientation; rather it offers, as an example, how adopting various theoretical positions from which to deconstruct education can and does provide for alternative perspectives both on educational policy and personal-professional viewpoints

A collaboration environment to support distributed eXtreme programming

NUL

Environmental Justice: Where are the Fracking Sites?

This paper looks at the variables that determine the location of hydraulic fracturing wells. Using cross-sectional data on Texas counties, we test whether county income level and the percentage of the population that is minority are significant indicators of well location. This study mirrors other studies that focus on the location of undesirable land uses such as landfills. Our study finds that income level and the size of the minority population are not statistically significant indicators of hydraulic fracturing well location

Governor's Dialogue on Health Care: Vision and Values

Summarizes discussions with over four hundred business, civic, nonprofit and healthcare community leaders about their vision for their healthcare system, the roles of employers, government, individuals, and the free market, and the values behind that vis

Urban Land Reform Briefing Paper No 6: Explaining Urban Partnership Zones

This is one of six briefing papers prepared by Professor David Adams of the University of Glasgow to help explain key proposals for urban land reform made in 2014 by the Scottish Government’s Land Reform Review Group (LRRG) to whom he acted as an independent adviser. This paper focuses on the LRRG’s recommendations “that the well-established international practice of property land readjustment or land-pooling provides another effective means of addressing fragmented or multiple ownership of land. The Group recommends that the Scottish Government investigates the potential of introducing an Urban Partnership Zone mechanism in Scotland” (see pages 126-128 of the LRRG report)

Improving the locality of the overlap Dirac operator via approximate solutions of the Ginsparg-Wilson relation

We determine the free field hypercubic Dirac operator which is optimally close to satisfying the Ginsparg-Wilson relation. Inserting this operator into the overlap formula, we show that the analytic locality bound on the resulting overlap Dirac operator is substantially stronger than in the standard case. This improvement generally persists in gauge backgrounds when the plaquette variables are all close to unity.Comment: 3 pages, contributed to Proceedings of Lattice2003(chiral