Femtosecond control of electric currents at the interfaces of metallic ferromagnetic heterostructures

The idea to utilize not only the charge but also the spin of electrons in the operation of electronic devices has led to the development of spintronics, causing a revolution in how information is stored and processed. A novel advancement would be to develop ultrafast spintronics using femtosecond laser pulses. Employing terahertz (10$^{12}$ Hz) emission spectroscopy, we demonstrate optical generation of spin-polarized electric currents at the interfaces of metallic ferromagnetic heterostructures at the femtosecond timescale. The direction of the photocurrent is controlled by the helicity of the circularly polarized light. These results open up new opportunities for realizing spintronics in the unprecedented terahertz regime and provide new insights in all-optical control of magnetism.Comment: 3 figures and 2 tables in the main tex

A functional variant in the Stearoyl-CoA desaturase gene promoter enhances fatty acid desaturation in pork

There is growing public concern about reducing saturated fat intake. Stearoyl-CoA desaturase (SCD) is the lipogenic enzyme responsible for the biosynthesis of oleic acid (18:1) by desaturating stearic acid (18:0). Here we describe a total of 18 mutations in the promoter and 3′ non-coding region of the pig SCD gene and provide evidence that allele T at AY487830:g.2228T>C in the promoter region enhances fat desaturation (the ratio 18:1/18:0 in muscle increases from 3.78 to 4.43 in opposite homozygotes) without affecting fat content (18:0+18:1, intramuscular fat content, and backfat thickness). No mutations that could affect the functionality of the protein were found in the coding region. First, we proved in a purebred Duroc line that the C-T-A haplotype of the 3 single nucleotide polymorphisms (SNPs) (g.2108C>T; g.2228T>C; g.2281A>G) of the promoter region was additively associated to enhanced 18:1/18:0 both in muscle and subcutaneous fat, but not in liver. We show that this association was consistent over a 10-year period of overlapping generations and, in line with these results, that the C-T-A haplotype displayed greater SCD mRNA expression in muscle. The effect of this haplotype was validated both internally, by comparing opposite homozygote siblings, and externally, by using experimental Duroc-based crossbreds. Second, the g.2281A>G and the g.2108C>T SNPs were excluded as causative mutations using new and previously published data, restricting the causality to g.2228T>C SNP, the last source of genetic variation within the haplotype. This mutation is positioned in the core sequence of several putative transcription factor binding sites, so that there are several plausible mechanisms by which allele T enhances 18:1/18:0 and, consequently, the proportion of monounsaturated to saturated fat.This research was supported by grants from the Spanish Ministry of Science and Innovation (AGL2009-09779 and AGL2012-33529). RRF is recipient of a PhD scholarship from the Spanish Ministry of Science and Innovation (BES-2010-034607). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of manuscript

GENERALIZED SOLUTIONS TO NONLINEAR 1ST-ORDER SYSTEMS

In the present work we reinterpret a result of approximate solutions to a nonlinear first order system in the framework of Colombeau's theory, defining an algebra of generalized germs where the problem u(t) = f(x,t,u,u(x)), u\t=0 = u(o)(x) has a unique solution, where f and u(o) are vector-valued functions.1184167172

BORELS THEOREM FOR GENERALIZED-FUNCTIONS

81217918

On the Benney-Lin and Kawahara equations

We establish global well-posedness for the initial value problem (IVP) associated to the so-called Benney-Lin equation. This model is a Korteweg-de Vries equation perturbed by dissipative and dispersive terms which appears in fluid dynamics. We also study the limiting behaviour of solutions to this IVP when the parameters of the perturbed terms approach 0. (C) 1997 Academic Press.211113115

GENERALIZED SOLUTIONS TO THE KORTEWEG-DEVRIES AND THE REGULARIZED LONG-WAVE EQUATIONS

In this article generalized solutions to two model equations describing nonlinear dispersive waves are studied. The solutions are found in certain algebras of new generalized functions containing spaces of distributions. On the one hand, this allows the handling of initial data with strong singularities. On the other hand, suitable scaling allows one to introduce an infinitesimally small coefficient; thereby the authors produce generalized solutions in the sense of Colombeau to the inviscid Burgers equation.23492394

GENERALIZED SOLUTIONS OF THE BENJAMIN-ONO AND SMITH EQUATIONS

182246548

Evolution PDE with elliptic dissipative terms: critical index for singular initial data, self-similar solutions and analytic regularity

We investigate the influence of the elliptic dissipative terms of evolution equations in R-n and T-n on the critical L-p, 1 less than or equal to p less than or equal to infinity, index of the singularity of the initial data, the analytic regularity for positive time and the existence of self-similar solutions. (C) Academie des Sciences/Elsevier, Paris.3271414

Fractional derivative estimates in Gevrey spaces, global regularity and decay for solutions to semilinear equations in R-n

We propose a unified functional analytic approach to study the uniform analytic-Gevrey regularity and the decay of solutions to semilinear elliptic equations on R-n. First, we develop a fractional calculus for nonlinear maps in Banach spaces of L-P based Gevrey functions, 1s(cr)>0 depending on the nonlinearity. Next, we investigate the type of decay-polynomial or exponential-of the derivatives of solutions to semilinear elliptic equations, provided they decay a priori slowly as o(\x\(-tau)), \x\ --> infinity for some small tau>0. The restrictions, involved in our results, are optimal. In particular, given a hyperplane L, we construct 2d - 2 strongly singular solutions (locally in H-P(s)(R-n) for s<s(cr)) to the semilinear Laplace equation Deltau + cu(d) = 0, whose singularities are concentrated on L. (C) 2003 Elsevier Inc. All rights reserved.194114016