THE RECOVERY OF MECHANICALLY ENTRAPPED PLUTONIUM FROM CASTING SKULLS AND TURNINGS

The small critical mass of plutonium which limits charge size, coupled with its value necessithting quantitative recovery from all residues, makes the direct recovery of mechanically entrapped plutonium from casting skulls and oxidized turnings an economic necessity. The newest method used at the Los Alamos Scientific Laboratory for the direct recovery of entrapped plutonium involves mechanical stirring and vibration of the plutonium melt to physically break up to spongy skull and oxide film, thus allowing the heavier molten plutonium to settle out at the bottom of the melt. The recovery equipment and procedures are described. (auth

Come Forth and Bring Your Garlands

https://digitalcommons.library.umaine.edu/mmb-me/1034/thumbnail.jp

Shape Space Methods for Quantum Cosmological Triangleland

With toy modelling of conceptual aspects of quantum cosmology and the problem of time in quantum gravity in mind, I study the classical and quantum dynamics of the pure-shape (i.e. scale-free) triangle formed by 3 particles in 2-d. I do so by importing techniques to the triangle model from the corresponding 4 particles in 1-d model, using the fact that both have 2-spheres for shape spaces, though the latter has a trivial realization whilst the former has a more involved Hopf (or Dragt) type realization. I furthermore interpret the ensuing Dragt-type coordinates as shape quantities: a measure of anisoscelesness, the ellipticity of the base and apex's moments of inertia, and a quantity proportional to the area of the triangle. I promote these quantities at the quantum level to operators whose expectation and spread are then useful in understanding the quantum states of the system. Additionally, I tessellate the 2-sphere by its physical interpretation as the shape space of triangles, and then use this as a back-cloth from which to read off the interpretation of dynamical trajectories, potentials and wavefunctions. I include applications to timeless approaches to the problem of time and to the role of uniform states in quantum cosmological modelling.Comment: A shorter version, as per the first stage in the refereeing process, and containing some new reference

Duchenne Muscular Dystrophy and Brain Function

Muscular dystrophies have historically been characterised according to clinical criteria, however in the genomic age the muscular dystrophies are now subdivided into groups according to the primary gene defect. Currently identified are 29 different loci and encoded proteins, giving rise to 34 distinct forms of muscular dystrophy (Dalkilic & Kunkel 2003;Hsu 2004). The majority of these types of muscular dystrophy are caused by perturbations of different components of the dystrophin-glycoprotein complex (DGC) an integral component of the cellular cytoskeleton (see below). Dystrophin is the largest component of the DGC and is absent in Duchenne muscular dystrophy (DMD), and severely truncated with decreased levels in Becker muscular dystrophy (BMD) (Hoffman & Kunkel 1989). DMD and the allelic BMD are the most common forms of muscular dystrophy in humans and together they are termed dystrophinopathies (Kingston et al. 1984; Shaw & Dreifuss1969). DMD alone accounts for approximately 80% of all the myopathies in the muscular dystrophy group (Culligan et al. 1998).The dystrophin gene is the second largest described to date, totalling 1.5% of the X chromosome, 0.1% of the entire genome. The DMD gene is 99% introns, with a coding sequence of 86 exons (including the promoters) and remains the only known human metagene (Blake et al. 2002; Burmeister et al. 1988; Hamed & Hoffmann 2006; Kenwrick et al. 1987; Koenig et al. 1987; Kunkel et al. 1986; Muntoni et al. 2003; Roberts et al. 1993; Smith et al. 2006; Van Ommen et al. 1987; Wallis et al. 2004). Dystrophin wasdemonstrated to be localised at the sarcolemma in human skeletal muscle after its’ genetic characterisation (Arahata et al. 1988; Sugita et al. 1988; Zubrzycka-Gaarn et al. 1988). This discovery was followed by a report of dystrophin messenger RNA in brain, with the protein being specifically localised at postsynaptic densities (PSD) in the CNS, in particular in the hippocampus, cerebral cortex and in cerebellar Purkinje cells (PC) (Chamberlain et al. 1988; Chelly et al. 1988, 1989; Lidov et al. 1990, Nudel et al. 1988)

Condensation Energy and High Tc Superconductivity

From an analysis of the specific heat of one of the cuprate superconductors it is shown, that even if a large part of the experimental specific heat associated with the superconducting phase transition is due to fluctuations, this part must be counted when one tries to extract the condensation energy from the data. Previous work by Chakravarty, Kee and Abrahams, where the fluctuation part was subtracted, has resulted in an incorrect estimation of the condensation energy.Comment: 4 pages, 5 encapsulated Postscript figures, uses ReVTeX.st

Exploring potential germline associated roles of the TRIM-NHL protein NHL-2 through RNAi screening

TRIM-NHL proteins are highly conserved regulators of developmental pathways in vertebrates and invertebrates. The TRIM-NHL family member NHL-2 in Caenorhabditis elegans functions as a miRNA cofactor to regulate developmental timing. Similar regulatory roles have been reported in other model systems, with the mammalian ortholog in mice, TRIM32, contributing to muscle and neuronal cell proliferation via miRNA activity. Given the interest associated with TRIM-NHL family proteins, we aimed to further investigate the role of NHL-2 in C. elegans development by using a synthetic RNAi screening approach. Using the ORFeome library, we knocked down 11,942 genes in wild-type animals and nhl-2 null mutants. In total, we identified 42 genes that produced strong reproductive synthetic phenotypes when knocked down in nhl-2 null mutants, with little or no change when knocked down in wild-type animals. These included genes associated with transcriptional processes, chromosomal integrity, and key cofactors of the germline small 22G RNA pathway.Gregory M. Davis, Wai Y. Low, Joshua W.T. Anderson and Peter R. Boa

Extrinsic Curvature and the Einstein Constraints

The Einstein initial-value equations in the extrinsic curvature (Hamiltonian) representation and conformal thin sandwich (Lagrangian) representation are brought into complete conformity by the use of a decomposition of symmetric tensors which involves a weight function. In stationary spacetimes, there is a natural choice of the weight function such that the transverse traceless part of the extrinsic curvature (or canonical momentum) vanishes.Comment: 8 pages, no figures; added new section; significant polishing of tex

A New Recursion Relation for the 6j-Symbol

The 6j-symbol is a fundamental object from the re-coupling theory of SU(2) representations. In the limit of large angular momenta, its asymptotics is known to be described by the geometry of a tetrahedron with quantized lengths. This article presents a new recursion formula for the square of the 6j-symbol. In the asymptotic regime, the new recursion is shown to characterize the closure of the relevant tetrahedron. Since the 6j-symbol is the basic building block of the Ponzano-Regge model for pure three-dimensional quantum gravity, we also discuss how to generalize the method to derive more general recursion relations on the full amplitudes.Comment: 10 pages, v2: title and introduction changed, paper re-structured; Annales Henri Poincare (2011

Condensation energy in strongly coupled superconductors

We consider the condensation energy in superconductors where the pairing is electronic in origin and is mediated by a collective bosonic mode. We use magnetically-mediated superconductivity as an example, and show that for large spin-fermion couplings, the physics is qualitatively different from the BCS theory as the condensation energy results from the feedback on spin excitations, while the electronic contribution to the condensation energy is positive due to an ``undressing'' feedback on the fermions. The same feedback effect accounts for the gain of the kinetic energy at strong couplings.Comment: 4 pages, revtex 4, 3 eps figure

New Media in the Muslim World: The Emerging Public Sphere

The Muslim world is experiencing a media explosion - from street-corner kiosks to satellite television and the Internet. Islamic messages and discussions of them are everywhere. They are proliferating, thanks to increasingly accessible, user-friendly technologies, from the already-familiar tapes and the lowly telephone to the hi-tech Internet, from pulp fiction to new law review journals, from popular culture magazines to multimedia Islamic educational material. Redrawing the dimensions of Islamic discourse, identity, and consciousness extends beyond audience fragmentation to an expanding public sphere of new genre and channels of expression for new voices and interpreters