On toric geometry, Spin(7) manifolds, and type II superstring compactifications

We consider type II superstring compactifications on the singular Spin(7) manifold constructed as a cone on SU(3)/U(1). Based on a toric realization of the projective space CP^2, we discuss how the manifold can be viewed as three intersecting Calabi-Yau conifolds. The geometric transition of the manifold is then addressed in this setting. The construction is readily extended to higher dimensions where we speculate on possible higher-dimensional geometric transitions. Armed with the toric description of the Spin(7) manifold, we discuss a brane/flux duality in both type II superstring theories compactified on this manifold.Comment: 14 pages, v2: version to be publishe

Effective Potential Theory: A Practical Way to Extend Plasma Transport Theory to Strong Coupling

The effective potential theory is a physically motivated method for extending traditional plasma transport theories to stronger coupling. It is practical in the sense that it is easily incorporated within the framework of the Chapman-Enskog or Grad methods that are commonly applied in plasma physics and it is computationally efficient to evaluate. The extension is to treat binary scatterers as interacting through the potential of mean force, rather than the bare Coulomb or Debye-screened Coulomb potential. This allows for aspects of many-body correlations to be included in the transport coefficients. Recent work has shown that this method accurately extends plasma theory to orders of magnitude stronger coupling when applied to the classical one-component plasma model. The present work shows that similar accuracy is realized for the Yukawa one-component plasma model and it provides a comparison with other approaches.Comment: 6 pages, 3 figures, Proceedings of the Strongly Coupled Coulomb Systems conference 201

New State Record and Notable Range Extension for \u3ci\u3eLibellula Semifasciata\u3c/i\u3e (Odonata: Libellulidae)

The painted skimmer, Libellula semifasciata Burmeister (Odonata: Libellulidae), is an eastern species of dragonfly that has never been documented in Iowa. In this note we report two observations and the collection of a voucher for this species in southeast Iowa in the last three years. Based on other records of this species, including those from neighboring states and more northerly latitudes, we propose that these observations are evidence of a range extension

Adaptive, cautious, predictive control with Gaussian process priors

Nonparametric Gaussian Process models, a Bayesian statistics approach, are used to implement a nonlinear adaptive control law. Predictions, including propagation of the state uncertainty are made over a k-step horizon. The expected value of a quadratic cost function is minimised, over this prediction horizon, without ignoring the variance of the model predictions. The general method and its main features are illustrated on a simulation example

The effects of reciprocal teaching upon year 6 students\u27 reading comprehension

The purpose of this study was to investigate the effects of Reciprocal Teaching on the reading comprehension of Year 6 students. Forty-one Year 6 students from two metropolitan primary schools took part in the study. An experimental pre-test - post-test control group design was used. Subjects were matched according to the results of the Test of Reading Comprehension (TORCH) used as a pre-test. Matched pair-mates were randomly allocated to either treatment or control groups. After 14 sessions of training in Reciprocal Teaching, results of an analysis of covariance (ANCOVA) with teachers nested in groups, showed no statistically significant differences in reading comprehension between the treatment and control groups. Some naive comprehenders (students who appear to lack knowledge about the purposes and strategies of reading), however, showed improvements when their data were analysed individually