Doped magnetic moments in a disordered electron system: insulator-metal transition, spin glass and `cmr'

Recent experiments on the amorphous magnetic semiconductor Gd_x Si_{1-x}, Phys. Rev. Lett. 77, 4652 (1996), ibid 83, 2266 (1999), ibid 84, 5411 (2000), ibid 85, 848 (2000), have revealed an insulator-metal transition (i-m-t), as a function of doping and magnetic field, a spin glass state at low temperature, and colossal magnetoresistance close to the i-m-t. There are also signatures of strong electron-electron interaction close to the i-m-t. Motivated by these results we examine the role of doped magnetic moments in a strongly disordered electron system. In this paper we study a model of electrons coupled to structural disorder and (classical) magnetic moments, through an essentially exact combination of spin Monte Carlo and fermion exact diagonalisation. Our preliminary results, ignoring electron-electron interactions, highlights the interplay of structural and magnetic `disorder' which is primarily responsible for the observed features in magnetism and transport.Comment: 12 pages, two column revtex, with 11 embedded figure

The exponential map for representations of Up,q(gl(2))U_{p,q}(gl(2))

For the quantum group $GL_{p,q}(2)$ and the corresponding quantum algebra $U_{p,q}(gl(2))$ Fronsdal and Galindo explicitly constructed the so-called universal $T$-matrix. In a previous paper we showed how this universal $T$-matrix can be used to exponentiate representations from the quantum algebra to get representations (left comodules) for the quantum group. Here, further properties of the universal $T$-matrix are illustrated. In particular, it is shown how to obtain comodules of the quantum algebra by exponentiating modules of the quantum group. Also the relation with the universal $R$-matrix is discussed.Comment: LaTeX-file, 7 pages. Submitted for the Proceedings of the 4th International Colloquium ``Quantum Groups and Integrable Systems,'' Prague, 22-24 June 199

Online Estimation and Optimization of Utility-Based Shortfall Risk

Utility-Based Shortfall Risk (UBSR) is a risk metric that is increasingly popular in financial applications, owing to certain desirable properties that it enjoys. We consider the problem of estimating UBSR in a recursive setting, where samples from the underlying loss distribution are available one-at-a-time. We cast the UBSR estimation problem as a root finding problem, and propose stochastic approximation-based estimations schemes. We derive non-asymptotic bounds on the estimation error in the number of samples. We also consider the problem of UBSR optimization within a parameterized class of random variables. We propose a stochastic gradient descent based algorithm for UBSR optimization, and derive non-asymptotic bounds on its convergence

Optimizing Closed Month Accounting by Utilizing Leases on Data Access and Editing

The present disclosure describes computer-implemented systems and methods for improved efficiency of closed month accounting procedures. More particularly, systems and methods can reduce system queries pertaining to a closed month by utilizing time-based locks, hereinafter “leases,” when preparing entries for the closed month. When a month begins to close, it is provided with a lease and an expiration time of the lease. During the lease, a user can commit entries to the closing month without creating data errors

KRT5 missense variant in a Cardigan Welsh Corgi with epidermolysis bullosa simplex.

Epidermolysis bullosa (EB) is a group of blistering disorders that includes several subtypes, classified according to their level of cleavage. Typical clinical signs are blisters and erosions resulting from minimal trauma. The disease has been described in many mammalian species and pathogenic variants in at least 18 different genes have been identified. In the present study, we investigated a Cardigan Welsh Corgi with congenital clinical signs consistent with epidermolysis bullosa. The puppy had blisters and erosions on the paw pads, and the oral mucosa. Histologic examination demonstrated the typical clefting between the dermis and epidermis and confirmed the clinical suspicion. We obtained whole genome sequencing data from the affected puppy and searched for variants in candidate genes known to cause EB. This revealed a heterozygous missense variant, KRT5:p.(E476K), affecting the highly conserved KLLEGE motif of keratin 5. The mutant allele in the affected puppy arose owing to a de novo mutation event as it was absent from both unaffected parents. Knowledge of the functional impact of KRT5 variants in other species together with the demonstration of the de novo mutation event establishes KRT5:p.(E476K) as causative variant for the observed EBS

Self-similarity under inflation and level statistics: a study in two dimensions

Energy level spacing statistics are discussed for a two dimensional quasiperiodic tiling. The property of self-similarity under inflation is used to write a recursion relation for the level spacing distributions defined on square approximants to the perfect quasiperiodic structure. New distribution functions are defined and determined by a combination of numerical and analytical calculations.Comment: Latex, 13 pages including 6 EPS figures, paper submitted to PR