Assessing Alternatives for Directional Detection of a WIMP Halo

The future of direct terrestrial WIMP detection lies on two fronts: new, much larger low background detectors sensitive to energy deposition, and detectors with directional sensitivity. The former can large range of WIMP parameter space using well tested technology while the latter may be necessary if one is to disentangle particle physics parameters from astrophysical halo parameters. Because directional detectors will be quite difficult to construct it is worthwhile exploring in advance generally which experimental features will yield the greatest benefits at the lowest costs. We examine the sensitivity of directional detectors with varying angular tracking resolution with and without the ability to distinguish forward versus backward recoils, and compare these to the sensitivity of a detector where the track is projected onto a two-dimensional plane. The latter detector regardless of where it is placed on the Earth, can be oriented to produce a significantly better discrimination signal than a 3D detector without this capability, and with sensitivity within a factor of 2 of a full 3D tracking detector. Required event rates to distinguish signals from backgrounds for a simple isothermal halo range from the low teens in the best case to many thousands in the worst.Comment: 4 pages, including 2 figues and 2 tables, submitted to PR

The occurrence of the extinct shark genus Sphenodus in the Jurassic of Sicily

During the systematic revision of some historical collections containing Mesozoic ammonites, housed at the "G.G. Gemmellaro" Geological Museum of the Palermo University, a fossil shark’s tooth has been discovered. This specimen, indicated as Lamna in the original catalogue, can be attributed to the genus Sphenodus, an extinct cosmopolitan shark ranging from Lower Jurassic rocks to the Paleocene. The specimen is part of the Mariano Gemmellaro Collection which mainly consists of Middle-Upper Jurassic ammonites coming from Tardàra Mountain, between Menfi and Sambuca di Sicilia (Agrigento Province, Southwestern Sicily). Some of the ammonite specimens were listed, but not illustrated, by M. Gemmellaro in a note of 1919. The succession described in this area consists (from bottom to the top) of Lower Jurassic shallow-water carbonates followed by condensed ammonitic limestones of “Rosso ammonitico-type” (Middle-Late Jurassic in age), Calpionellid limestones (Upper Jurassic-Lower Cretaceous) and cherty calcilutites of Scaglia-type (Upper Cretaceous-Eocene). Since the exact stratigraphic level from which the shark tooth comes is not recorded, a thin section was made of the rock matrix surrounding the tooth. The sedimentological and paleontological analysis of the thin section has highlighted the presence of a microfacies characteristic of the Upper Jurassic condensed deposits of Rosso ammonitico-type, data that fits very well with the geology of the Tardàra area. The study of the Tardàra shark’s tooth has provided both the stimulus and opportunity to undertake a taxonomic review of the Jurassic specimens of Sphenodus collected from a range of Sicilian localities (Gemmellaro G.G., 1871; Seguenza G., 1887; Di Stefano & Cortese, 1891; Seguenza L., 1900; De Gregorio A., 1922) that, to date, have not been re-examined in the light of more recent scholarship. In particular, the specimens described and illustrated by G.G. Gemmellaro (1871), and stored in his eponymous museum, have been revised with the aim of providing a contribution to our knowledge of the genus Sphenodus in the Sicilian Mesozoic successions

Discrete complex analysis on planar quad-graphs

We develop a linear theory of discrete complex analysis on general quad-graphs, continuing and extending previous work of Duffin, Mercat, Kenyon, Chelkak and Smirnov on discrete complex analysis on rhombic quad-graphs. Our approach based on the medial graph yields more instructive proofs of discrete analogs of several classical theorems and even new results. We provide discrete counterparts of fundamental concepts in complex analysis such as holomorphic functions, derivatives, the Laplacian, and exterior calculus. Also, we discuss discrete versions of important basic theorems such as Green's identities and Cauchy's integral formulae. For the first time, we discretize Green's first identity and Cauchy's integral formula for the derivative of a holomorphic function. In this paper, we focus on planar quad-graphs, but we would like to mention that many notions and theorems can be adapted to discrete Riemann surfaces in a straightforward way. In the case of planar parallelogram-graphs with bounded interior angles and bounded ratio of side lengths, we construct a discrete Green's function and discrete Cauchy's kernels with asymptotics comparable to the smooth case. Further restricting to the integer lattice of a two-dimensional skew coordinate system yields appropriate discrete Cauchy's integral formulae for higher order derivatives.Comment: 49 pages, 8 figure

Equation of the field lines of an axisymmetric multipole with a source surface

Optical spectropolarimeters can be used to produce maps of the surface magnetic fields of stars and hence to determine how stellar magnetic fields vary with stellar mass, rotation rate, and evolutionary stage. In particular, we now can map the surface magnetic fields of forming solar-like stars, which are still contracting under gravity and are surrounded by a disk of gas and dust. Their large scale magnetic fields are almost dipolar on some stars, and there is evidence for many higher order multipole field components on other stars. The availability of new data has renewed interest in incorporating multipolar magnetic fields into models of stellar magnetospheres. I describe the basic properties of axial multipoles of arbitrary degree ℓ and derive the equation of the field lines in spherical coordinates. The spherical magnetic field components that describe the global stellar field topology are obtained analytically assuming that currents can be neglected in the region exterior to the star, and interior to some fixed spherical equipotential surface. The field components follow from the solution of Laplace’s equation for the magnetostatic potential

Association Between p.Leu54Met Polymorphism at the Paraoxonase-1 Gene and Plantar Fascia Thickness in Young Subjects With Type 1 Diabetes

OBJECTIVE— In type 1 diabetes, plantar fascia, a collagen-rich tissue, is susceptible to glycation and oxidation. Paraoxonase-1 (PON1) is an HDL-bound antioxidant enzyme. PON1 polymorphisms have been associated with susceptibility to macro- and microvascular complications. We investigated the relationship between plantar fascia thickness (PFT) and PON1 gene variants, p.Leu54Met, p.Gln192Arg, and c.-107C>T, in type 1 diabetes

Development and fabrication of a fast recovery, high voltage power diode

The use of positive bevels for P-I-N mesa structures to achieve high voltages is described. The technique of glass passivation for mesa structures is described. The utilization of high energy radiation to control the lifetime of carriers in silicon is reported as a means to achieve fast recovery times. Characterization data is reported and is in agreement with design concepts developed for power diodes

Critical temperature oscillations in magnetically coupled superconducting mesoscopic loops

We study the magnetic interaction between two superconducting concentric mesoscopic Al loops, close to the superconducting/normal phase transition. The phase boundary is measured resistively for the two-loop structure as well as for a reference single loop. In both systems Little-Parks oscillations, periodic in field are observed in the critical temperature Tc versus applied magnetic field H. In the Fourier spectrum of the Tc(H) oscillations, a weak 'low frequency' response shows up, which can be attributed to the inner loop supercurrent magnetic coupling to the flux of the outer loop. The amplitude of this effect can be tuned by varying the applied transport current.Comment: 9 pages, 7 figures, accepted for publication in Phys. Rev.

Discrete conformal maps: boundary value problems, circle domains, Fuchsian and Schottky uniformization

We discuss several extensions and applications of the theory of discretely conformally equivalent triangle meshes (two meshes are considered conformally equivalent if corresponding edge lengths are related by scale factors attached to the vertices). We extend the fundamental definitions and variational principles from triangulations to polyhedral surfaces with cyclic faces. The case of quadrilateral meshes is equivalent to the cross ratio system, which provides a link to the theory of integrable systems. The extension to cyclic polygons also brings discrete conformal maps to circle domains within the scope of the theory. We provide results of numerical experiments suggesting that discrete conformal maps converge to smooth conformal maps, with convergence rates depending on the mesh quality. We consider the Fuchsian uniformization of Riemann surfaces represented in different forms: as immersed surfaces in \mathbb {R}^{3}, as hyperelliptic curves, and as \mathbb {CP}^{1} modulo a classical Schottky group, i.e., we convert Schottky to Fuchsian uniformization. Extended examples also demonstrate a geometric characterization of hyperelliptic surfaces due to Schmutz Schaller