Dispersion managed mode-locking dynamics in a Ti:Sapphire laser

We present what is to our knowledge the most complete 1-D numerical analysis of the evolution and the propagation dynamics of an ultrashort laser pulse in a Ti:Sapphire laser oscillator. This study confirms the dispersion managed model of mode-locking, and emphasizes the role of the Kerr nonlinearity in generating mode-locked spectra with a smooth and well-behaved spectral phase. A very good agreement with preliminary experimental measurements is found.Comment: 11 pages, 4 figures, submitted to Optics Letter

Topological superconductivity in lead nanowires

Superconductors with an odd number of bands crossing the Fermi energy have topologically protected Andreev states at interfaces, including Majorana states in one dimensional geometries. Superconductivity, a low number of 1D channels, large spin orbit coupling, and a sizeable Zeeman energy, are present in lead nanowires produced by nanoindentation of a Pb tip on a Pb substrate, in magnetic fields higher than the Pb bulk critical field. A number of such devices have been analyzed. In some of them, the dependence of the critical current on magnetic field, and the Multiple Andreev Reflections observed at finite voltages, are compatible with the existence of topological superconductivity

Solitary-wave vortices in quadratic nonlinear media

We find families of vortex solitary waves in bulk quadratic nonlinear media under conditions for second-harmonic generation. We show that the vortex solitary waves are azimuthally unstable and that they decay into sets of stable spatial solitons. We calculate the growth rates of the azimuthal perturbations and show how those affect the pattern of output light. © 1998 Optical Society of AmericaPeer ReviewedPostprint (published version

Probing halo nucleus structure through intermediate energy elastic scattering

This work addresses the question of precisely what features of few body models of halo nuclei are probed by elastic scattering on protons at high centre-of-mass energies. Our treatment is based on a multiple scattering expansion of the proton-projectile transition amplitude in a form which is well adapted to the weakly bound cluster picture of halo nuclei. In the specific case of $^{11}$Li scattering from protons at 800 MeV/u we show that because core recoil effects are significant, scattering crosssections can not, in general, be deduced from knowledge of the total matter density alone. We advocate that the optical potential concept for the scattering of halo nuclei on protons should be avoided and that the multiple scattering series for the full transition amplitude should be used instead.Comment: 8 pages REVTeX, 1 eps figure, accepted for publication in Phys. Rev.

The Kinematics of HH 34 from HST Images with a Nine-year Time Baseline

We study archival HST [S II] 6716+30 and Hα images of the HH 34 outflow, taken in 1998.71 and in 2007.83. The ~9 yr time baseline and the high angular resolution of these observations allow us to carry out a detailed proper-motion study. We determine the proper motions of the substructure of the HH 34S bow shock (from the [S II] and Hα frames) and of the aligned knots within ~30'' from the outflow source (only from the [S II] frames). We find that the present-day motions of the knots along the HH 34 jet are approximately ballistic, and that these motions directly imply the formation of a major mass concentration in ~900 yr, at a position similar to the one of the present-day HH 34S bow shock. In other words, we find that the knots along the HH 34 jet will merge to form a more massive structure, possibly resembling HH 34S

Magnetic-dipole transition probabilities in B-like and Be-like ions

The magnetic-dipole transition probabilities between the fine-structure levels (1s^2 2s^2 2p) ^2P_1/2 - ^2P_3/2 for B-like ions and (1s^2 2s 2p) ^3P_1 - ^3P_2 for Be-like ions are calculated. The configuration-interaction method in the Dirac-Fock-Sturm basis is employed for the evaluation of the interelectronic-interaction correction with negative-continuum spectrum being taken into account. The 1/Z interelectronic-interaction contribution is derived within a rigorous QED approach employing the two-time Green function method. The one-electron QED correction is evaluated within framework of the anomalous magnetic-moment approximation. A comparison with the theoretical results of other authors and with available experimental data is presented

Spiders from Macaronesia: Cabo Verde.

ABSTRACT: The data presented in this study were obtained from samples collected as part of the project "Macaronesian Islands as a testing ground to assess biodiversity drivers at multiple scales" (FCT - MACDIV) (2015-2018). This project aimed at gaining insights into the factors influencing community assembly in Macaronesian islands. To assess spider diversity, we employed the COBRA (Conservation Oriented Biodiversity Rapid Assessment) sampling protocol. Our sampling efforts were conducted in ten 50 m x 50 m dry shrub plots located on the Cabo Verde Islands of Santo Antão (comprising five plots) and São Vicente (comprising five plots). Additional ad-hoc samples are also available. With this publication, we contribute valuable information to the understanding of the arachnofauna of Cabo verde, specifically focusing on the islands of Santo Antão and São Vicente.info:eu-repo/semantics/publishedVersio

Weissella halotolerans W22 combines arginine deiminase and ornithine decarboxylation pathways and converts arginine to putrescine

Aims: To demonstrate that the meat food strain Weissella halotolerans combines an ornithine decarboxylation pathway and an arginine deiminase (ADI) pathway and is able to produce putrescine, a biogenic amine. Evidence is shown that these two pathways produce a proton motive force (PMF). Methods and Results: Internal pH in W. halotolerans was measured with the sensitive probe 2',7'-bis-(2-carboxyethyl)-5(and-6)-carboxyfluorescein. Membrane potential was measured with the fluorescent probe 3,3'-dipropylthiocarbocyanine iodine. Arginine and ornithine transport studies were made under several conditions, using cells loaded or not loaded with the biogenic amine putrescine. ADI pathway caused an increase in Delta pH dependent on the activity of F(0)F(1)ATPase. Ornithine decarboxylation pathway generates both a Delta pH and a Delta Psi. Both these pathways lead to the generation of a PMF. Conclusions: Weissella halotolerans W22 combines an ADI pathway and an ornithine decarboxylation pathway, conducing to the production of the biogenic amine putrescine and of a PMF. Transport studies suggest the existence of a unique antiporter arginine/putrescine in this lactic acid bacteria strain. Significance and Impact of the Study: The coexistence of two different types of amino acid catabolic pathways, leading to the formation of a PMF, is shown for a Weissella strain for the first time. Moreover, a unique antiport arginine/putrescine is hypothesized to be present in this food strain