Detecting supersymmetric Q-balls with neutron stars

Supersymmetric Q-balls trapped in neutron stars or white dwarfs may cause the stars to explode. Trapping of Q-balls in neutron stars is shown to be less likely, but trapping in neutron star progenitors more likely than hitherto assumed, making neutron stars very sensitive Q-ball "detectors". White dwarfs only trap potentially dangerous Q-balls in a narrow parameter range.Comment: 6 pages, 2 figures, accepted for publication in Physics Letters

On the Classification of Real Forms of Non-Abelian Toda Theories and W-algebras

We consider conformal non-Abelian Toda theories obtained by hamiltonian reduction from Wess-Zumino-Witten models based on general real Lie groups. We study in detail the possible choices of reality conditions which can be imposed on the WZW or Toda fields and prove correspondences with sl(2,R) embeddings into real Lie algebras and with the possible real forms of the associated W-algebras. We devise a a method for finding all real embeddings which can be obtained from a given embedding of sl(2,C) into a complex Lie algebra. We then apply this to give a complete classification of real embeddings which are principal in some simple regular subalgebra of a classical Lie algebra.Comment: 42 pages, LaTeX; Minor corrections to ensure consistent conventions; some references adde

Q-balls in Underground Experiments

In this paper we present some features of Q-balls and we discuss their interactions with matter, and their energy losses in the Earth, for a large range of velocities. These calculations are used to compute the fractional geometrical acceptance of the MACRO detector. Furthermore a systematic analysis of the energy losses of Q-balls in three types of detectors is investigated. More specifically we have computed the light yield in liquid scintillators, the ionization in streamer tubes and the Restricted Energy Loss in the CR39 nuclear track detectors.Comment: 7 pages, 4 PS figures included with epsfig, uses espcrc2.sty Talk given at the Sixth Topical Seminar on Neutrino and Astroparticle Physics, San Miniato, Italy, 17-21 May 199

Electronic structure of the ferromagnetic superconductor UCoGe from first principles

The superconductor UCoGe is analyzed with electronic structure calculations using Linearized Augmented Plane Wave method based on Density Functional Theory. Ferromagnetic and antiferromagnetic calculations with and without correlations (via LDA+U) were done. In this compound the Fermi level is situated in a region where the main contribution to DOS comes from the U-5f orbital. The magnetic moment is mainly due to the Co-3d orbital with a small contribution from the U-5f orbital. The possibility of fully non-collinear magnetism in this compound seems to be ruled out. These results are compared with the isostructural compound URhGe, in this case the magnetism comes mostly from the U-5f orbital

Programming with Purity Reflection: Peaceful Coexistence of Effects, Laziness, and Parallelism

We present purity reflection, a programming language feature that enables higher-order functions to inspect the purity of their function arguments and to vary their behavior based on this information. The upshot is that operations on data structures can selectively use lazy and/or parallel evaluation while ensuring that side effects are never lost or re-ordered. The technique builds on a recent Hindley-Milner style type and effect system based on Boolean unification which supports both effect polymorphism and complete type inference. We illustrate that avoiding the so-called \u27poisoning problem\u27 is crucial to support purity reflection. We propose several new data structures that use purity reflection to switch between eager and lazy, sequential and parallel evaluation. We propose a DelayList, which is maximally lazy but switches to eager evaluation for impure operations. We also propose a DelayMap which is maximally lazy in its values, but also exploits eager and parallel evaluation. We implement purity reflection as an extension of the Flix programming language. We present a new effect-aware form of monomorphization that eliminates purity reflection at compile-time. And finally, we evaluate the cost of this new monomorphization on compilation time and on code size, and determine that it is minimal

On smoothable surgery for 4-manifolds

Under certain homological hypotheses on a compact 4-manifold, we prove exactness of the topological surgery sequence at the stably smoothable normal invariants. The main examples are the class of finite connected sums of 4-manifolds with certain product geometries. Most of these compact manifolds have non-vanishing second mod 2 homology and have fundamental groups of exponential growth, which are not known to be tractable by Freedman-Quinn topological surgery. Necessarily, the *-construction of certain non-smoothable homotopy equivalences requires surgery on topologically embedded 2-spheres and is not attacked here by transversality and cobordism.Comment: 18 pages, separated into two journal submission

On the estimation of normal copula discrete regression models using the continuous extension and simulated likelihood

The continuous extension of a discrete random variable is amongst the computational methods used for estimation of multivariate normal copula-based models with discrete margins. Its advantage is that the likelihood can be derived conveniently under the theory for copula models with continuous margins, but there has not been a clear analysis of the adequacy of this method. We investigate the asymptotic and small-sample efficiency of two variants of the method for estimating the multivariate normal copula with univariate binary, Poisson, and negative binomial regressions, and show that they lead to biased estimates for the latent correlations, and the univariate marginal parameters that are not regression coefficients. We implement a maximum simulated likelihood method, which is based on evaluating the multidimensional integrals of the likelihood with randomized quasi Monte Carlo methods. Asymptotic and small-sample efficiency calculations show that our method is nearly as efficient as maximum likelihood for fully specified multivariate normal copula-based models. An illustrative example is given to show the use of our simulated likelihood method

Big Changes in How Students are Tested

For the past decade, school accountability has relied on tests for which the essential format has remained unchanged. Educators are familiar with the yearly testing routine: schools are given curriculum frameworks, teachers use the frameworks to guide instruction, students take one big test at year’s end which relies heavily upon multiple-choice bubble items, and then school leaders wait anxiously to find out whether enough of their students scored at or above proficiency to meet state standards. All this will change with the adoption of Common Core standards. Testing and accountability aren’t going away. Instead, they are developing and expanding in ways that aim to address many of the present shortcomings of state testing routines. Most importantly, these new tests will be computer-based. As such, they will potentially shorten testing time, increase tests’ precision, and provide immediate feedback to students and teachers

DEVELOPMENT OF A TEST PROTOCOL TO IDENTIFY POTENTIAL RISK FACTORS FOR LOWER LIMB INJURIES IN BALLET DANCERS

The aim of the present study was to develop a test protocol to identify potential risk factors for lower limb injuries during ballet jump landings. Two ballet dancers, a beginner level and an advanced level dancer, participated in the study. The dancers performed multiple Sautés in first position, Grand Jeté, and Grand Pas de Chat jump landings on a plantar pressure mat on top of a force platform. The participants wore ballet slipper thongs, while a three-segment kinematic model of the foot was used to provide a more detailed understanding of foot posture during landings, and to investigate how the dancers adapted to the high foot/ankle loadings. Potential risk factors were identified as high free moment peaks, high impact velocities, and improper technique with missing turnouts during landings. Furthermore, there seems a potential to distinguish between dancers’ ability levels and associated injury risks