Propagation of localized surface plasmons in sets of metallic nanocylinders at the exit of subwavelength slits

We analyze, by means of numerical simulations, transmission enhancements through sub- wavelength slits due to the presence of sets of plasmonic nanocylinders, placed near the exit of these apertures. Further, we extend this study to photonic crystals of dipolar plasmonic particles in front of an array of extraordinarily transmitting slits practiced in a metallic slab.Comment: 20 pages, 9 figures. Submitted to Journal of Nanophotonic

H2 distribution during 2-phase Molecular Cloud Formation

We performed high-resolution, 3D MHD simulations and we compared to observations of translucent molecular clouds. We show that the observed populations of rotational levels of H2 can arise as a consequence of the multi-phase structure of the ISM.Comment: 2 pages, 1 figure. Due to appear in the proceedings of the 6th Zermatt ISM Symposium: "Conditions and Impact of Star Formation: From Lab to Space

A holistic approach to enhance the use of neglected and underutilized species: the case of Andean grains in Bolivia and Peru

The IFAD-NUS project, implemented over the course of a decade in two phases, represents the first UN-supported global effort on neglected and underutilized species (NUS). This initiative, deployed and tested a holistic and innovative value chain framework using multi-stakeholder, participatory, inter-disciplinary, pro-poor gender- and nutrition-sensitive approaches. The project has been linking aspects often dealt with separately by R&D, such as genetic diversity, selection, cultivation, harvest, value addition, marketing, and final use, with the goal to contribute to conservation, better incomes, and improved nutrition and strengthened livelihood resilience. The project contributed to the greater conservation of Andean grains and their associated indigenous knowledge, through promoting wider use of their diversity by value chain actors, adoption of best cultivation practices, development of improved varieties, dissemination of high quality seed, and capacity development. Reduced drudgery in harvest and postharvest operations, and increased food safety were achieved through technological innovations. Development of innovative food products and inclusion of Andean grains in school meal programs is projected to have had a positive nutrition outcome for targeted communities. Increased income was recorded for all value chain actors, along with strengthened networking skills and self-reliance in marketing. The holistic approach taken in this study is advocated as an effective strategy to enhance the use of other neglected and underutilized species for conservation and livelihood benefits

Hamster-to-rat heart and liver xenotransplantation with FK506 plus antiproliferative drugs

Heterotopic hamster hearts transplanted to unmodified LEW rats underwent humoral rejection in 3 days. Survival was prolonged to a median of 4 days with 2 mg/kg/day FK506. As monotherapy, 15 mg/kg/day cyclophosphamide greatly prolonged graft survival-far more than could be accomplished with RS-61443, brequinar (BQR), mizoribine, methotrexate, or deoxyspergualin. However, when FK506 treatment, which was ineffective alone, was combined with a short induction course (14 or 30 days) of subtherapeutic BQR, RS-61443, or cyclophosphamide, routine survival of heart xenografts was possible for as long as the daily FK506 was continued. In addition, a single large dose of 80 mg/kg cyclophosphamide 10 days preoperatively allowed routine cardiac xenograft survival under FK506. The ability of these antimetabolites to unmask the therapeutic potential of FK506 correlated, although imperfectly, with the prevention of rises of preformed heterospecific cytotoxic antibodies immediately postoperatively. As an adjunct to FK506, azathioprine was of marginal value, whereas mizoribine, methotrexate, and deoxyspergualin (DSPG) were of intermediate efficacy. After orthotopic hepatic xenotransplantation, the perioperative survival of the liver with its well-known resistance to antibodies was less dependent than the heart on the antimetabolite component of the combined drug therapy, but the unsatisfactory results with monotherapy of FK506, BQR, RS-61443, or cyclophosphamide were changed to routine success by combining continuous FK506 with a short course of any of the other drugs. Thus, by breaking down the antibody barrier to xenotransplantation with these so-called antiproliferative drugs, it has been possible with FK506 to transplant heart and liver xenografts with consistent long-term survival of healthy recipients

Donor species complement after liver xenotransplantation: The mechanism of protection from hyperacute rejection

Hamster hearts transplanted into stable rat recipients of hamster livers (OLT rats) were hyperacutely rejected after transfer with unaltered rat antihamster hyperimmune serum (HS). This was followed by immediate liver xenograft rejection in 4 of 5 rats. In contrast, simple heat inactivation of the rat HS resulted in prolonged survival of hamster hearts to 25 days without deterioration effect in the liver xenografts. This effect was species-specific because third-party mouse heart grafts in OLT rats were hyperacutely rejected in minutes if either active or heat inactivated antimouse HS was given. In cytotoxicity experiments, the complement in OLT serum produced weak lysis of hamster lymphocytes, while efficiently doing so with mouse cell targets. Because normal hamster serum caused no lysis at all of hamster target cells, the residual low-grade lysis of OLT serum was possibly being mediated by extrahepatic sources of rat C. In conclusion, the homology of C and target cells represents a mechanism of protection that the liver confers to other organs, and that is most easily seen in xenografts but may be allospecifically operational with allografts as well within the limits of MHC restriction. © 1994 by Williams and Wilkins

Early Cretaceous absolute geomagnetic paleointensities from Córdoba province (Argentina)

We present here new paleointensity and geochronology results from Early Cretaceous volcanic rocks of Sierra Chica de Cordoba (Argentina). The new K-Ar isotopic ages of 5 samples range from 136 to 122 Ma. Twenty five samples from 7 individual flows yielded acceptable paleointensity estimates. The mean paleointensity values per flow are ranging from 53.0±1.9 to 25.4±2.6 μT and the corresponding Virtual Dipole Moments (VDMs) are ranging from 9.3±1.3 to 4.6±0.5 (1022 Am2). This corresponds to the mean value of 7.3±1.7x1022 Am2, which is compatible to the present geomagnetic axial dipole. Currently available selected paleointensity data from 80 to 130 Ma suggest that geomagnetic field strength frequently fluctuated before and during the Cretaceous Normal Superchron while the magnetic polarity maintained stable. The mean paleointensities derived from Cordoba lavas agree remarkably well with those obtained from the Parana Magmatic Province (133-132 Ma). This reinforces the hypothesis about the unreliability of ‘Mesozoic Dipole Low'.Fil: Cejudo Ruiz, Ruben. Universidad Nacional Autónoma de México; MéxicoFil: Goguitchaichvili, Avto. Universidad Nacional Autónoma de México; MéxicoFil: Geuna, Silvana Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Alva-Valdivia, Luis M.. Universidad Nacional Autónoma de México; MéxicoFil: Solé, Jesus. Universidad Nacional Autónoma de México; MéxicoFil: Morales, Juan. Universidad Nacional Autónoma de México; Méxic

Multi-Fluid Simulation of the Magnetic Field Evolution in Neutron Stars

Using a numerical simulation, we study the effects of ambipolar diffusion and ohmic diffusion on the magnetic field evolution in the interior of an isolated neutron star. We are interested in the behavior of the magnetic field on a long time scale, over which all Alfven and sound waves have been damped. We model the stellar interior as an electrically neutral plasma composed of neutrons, protons and electrons, which can interact with each other through collisions and electromagnetic forces. Weak interactions convert neutrons and charged particles into each other, erasing chemical imbalances. As a first step, we assume that the magnetic field points in one fixed Cartesian direction but can vary along an orthogonal direction. We start with a uniform-density background threaded by a homogeneous magnetic field and study the evolution of a magnetic perturbation as well as the density fluctuations it induces in the particles. We show that the system evolves through different quasi-equilibrium states and estimate the characteristic time scales on which these quasi-equilibria occur.Comment: It will be published in AIP Proceedings of the Conference '40 Years of Pulsars: Milisecond Pulsars, Magnetars and More' held at University of McGill, Montreal, Canada, August 2007. Contributed Talk at Conference '40 Years of Pulsars: Milisecond Pulsars, Magnetars and More