Stabilization of vortex beams in Kerr media by nonlinear absorption

We elaborate a new solution for the problem of stable propagation of transversely localized vortex beams in homogeneous optical media with self-focusing Kerr nonlinearity. Stationary nonlinear Bessel-vortex states are stabilized against azimuthal breakup and collapse by multiphoton absorption, while the respective power loss is offset by the radial influx of the power from an intrinsic reservoir. A linear stability analysis and direct numerical simulations reveal a region of stability of these vortices. Beams with multiple vorticities have their stability regions too. These beams can then form robust tubular filaments in transparent dielectrics as common as air, water and optical glasses at sufficiently high intensities. We also show that the tubular, rotating and speckle-like filamentation regimes, previously observed in experiments with axicon-generated Bessel beams, can be explained as manifestations of the stability or instability of a specific nonlinear Bessel-vortex state, which is fully identified.Comment: Physical Review A, in press, 9 pages, 6 figure

The portuguese self-administered computerised 24-hour dietary recall

Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.Rationale: Measuring the diets of school-aged children is a challenging process. Technology offers the opportunity to automate more accurate methods of dietary assessment, making them less expensive, easier to use and an alternative to nutritionist interviews.info:eu-repo/semantics/publishedVersio

Plant data survey in Porto Santo (Madeira Archipelago, Portugal): an update

The present contribution updates BORGES et al. (2008)’s “A list of the terrestrial fungi, flora and fauna of Madeira and Selvagens archipelagos”. Since then, and until the summer of 2019, 131 new taxa were cited, namely 30 bryophytes, one pteridophyte and 100 spermatophytes. Based on the compilation of written and unpublished information about the diversity of terrestrial plants cited for Porto Santo, the present work lists 696 taxa, including 134 bryophytes, 13 pteridophytes and 549 spermatophytes. Two species of mosses, Sematophyllum substrumulosum (Hampe) E. Britton and Tortula lanceolata R. H. Zander are recorded for the first time from Porto Santo, corresponding to material collected in 2018. Additionally, 12 species of spermatophytes, all cultivated, are referred for the first time to the island. Two species of pteridophytes, Ophioglossum lusitanicum L. and Hymenophyllum wilsonii Hook are proposed to be considered extinct.info:eu-repo/semantics/publishedVersio

Citrate and isocitrate in plant metabolism

The relevance of citrate and isocitrate metabolism in plants is discussed in connection with the different pathways for their conversions. The routes for citrate and isocitrate conversions are incorporated into the system of cross-linked metabolic processes and may provide carbon skeletons for nitrogen assimilation and reducing equivalents for biosynthetic reactions, support the functioning of the glyoxylate cycle and play an important role in the TCA and energy metabolism as a whole. The possibility of the coupling of citrate and isocitrate metabolism with various electron transport systems is discussed from the point of view of the efficiency of the balancing cellular NAD P H Ž . Ž . rNAD P and ATP q rADP ratios. The role of citrate and isocitrate and their derivations as potent effectors of some enzymes is considered. Special attention is paid to the enzymes associated with citrate and isocitrate metabolism and to the mechanisms which regulate their activity. The possibilities of the coordination of the main processes of energy and biosynthetic metabolism at the level of citrate and isocitrate distribution are discussed.The authors are grateful to Dr., Professor, Academician of the Russian Academy of Sciences, V.P. ŽSkulachev Moscow State University, Institute of. Molecular Biology for carefully and critically reading the manuscript and stimulating discussions. We also thank Dr. Teresa M. Santos for her help during the preparation of the manuscript. The work of Prof. Tatyana N. Popova in Madeira University was supported by the grant no. 9r96r1r0618 of the Portuguese Foundation for Support of the Scientific Community JNICT and the Madeiran Scientific and Ž . Technological Centre CITMA . Ž .info:eu-repo/semantics/publishedVersio

International business tourism : a growth rate model

The aim of this paper is to understand the factors influencing business tourism on a global scale, in order to assess the competence of the countries in this tourism segment and prescribe them guidelines for action. For the development of data analysis, a growth rate model was estimated and a sample of 136 countries for the years 2005 and 2009 was collected. Results reveal that, for the development of policies to stimulate the growth in the business tourism segment, countries should develop measures that encourage capital investment in tourism, leisure tourism and trade openness.8316-FD77-85EB | Pedro Miguel Fonseca Moreira de CarvalhoN/

Monitoring and control system of discomfort in disability, bed rest people and surgical patients

Project aims to develop a system that allows to provide to the People with Special Needs(PSN) a relief to the level of the sensitive perception of discomfort, assuring greater independence,welfare, quality of life, prevention of illnesses/wounds, through the development of textile and polymers applications (cushions, mattresses and mattresses overlays) with functions of monitoring and control of pressure in the body's areas in contact with the support surfaces. In this group of PSN will be enclosed the people with serious motor limitations conditioning their mobility/deambulation, such as bed rest people, patients under effect of sedatives or anaesthesia during long surgeries (intra and post operative), patients and users in general of wheelchairs. These people have, for the most part of the cases, a commitment of sensitivity in the body's areas in contact with the support surfaces, or its motor capacity does not allow them to move regularly of position autonomously, as it would do a healthy person unconsciously. Then, insufficient sanguineous irrigation occurs as result of pressure exceeding too long the tissue capillary pressure depriving tissues of oxygen and essential nutrients, owing to ischemia and hypoxia, which then causes the pressure ulcers (PU) development

Analysis of body differences for the design of children's clothing

This paper discusses anthropometric data obtained through 3D body scanner technology, aiming the dimensioning of Portuguese children's measurements for the design of clothing. The study comprises boys and girls from the Northern Region of Portugal aged between two and ten years old. The main objective of this part of the study was to evaluate the possibility of grouping children with six and seven years old in a same garment size, proposing the same body measurements in the final standard measurements table. In addition to the children's anthropometric measurements, it was checked the body conformation of the children and the possibility of identifying the main biotypes. As a preliminary result, through cluster analysis it was found that it is possible to combine these children in the same group in the proposed standard measurements table.POFC - Programa Operacional Temático Factores de Competitividade(UID/CTM/000264