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

Credibilidade da Política Monetária e a Previsão do Trade-off entre Inflação e Desemprego: Uma Aplicação para o Brasil

This paper evaluates, as proposed by Laxton and N’Diaye (2002), if the consideration of a measure of monetary policy credibility in the forecast of the Brazilian Phillips Curve, after the introduction of inflation targeting, implies an improvement. The findings denote that the use of a measure of monetary policy credibility for the Brazilian economy can provide a statistical model with a forecast quality for unemployment-inflation trade-off better than models of inflation that consider a stable relation between inflation expectations and inflation.Credibilidade, Trade-Off entre Inflação e Desemprego, Metas para Inflação Bank, Fear of Floating

Niveles de ansiedad en jugadores de elite de equipos de rugby «Sub-18» y «Sub-20» en diferentes posiciones de campo

The objective of this study was to encourage Rugby players to promote abilities in this sport, therefore we have evaluated the somatic anxiety, cognitive anxiety and self-confidence values of U18 and U20 rugby athletes of the Portuguese Nationals Rugby Teams, who participated respectively in the U18 Elite European Championship and in the U20 Trophy World Rugby, comparing forwards and defenders. For data collection, we used the CSAI-2 which assesses cognitive anxiety, somatic anxiety and self-confidence. The results showed more favourable average parameters for the group of athletes U20. However, there were only significant differences favourable to the U20 team in the domain of self-confidence, in a general level between teams and in the forward positions.El objetivo de este estudio fue animar a los jugadores de rugby para promover las habilidades en este deporte, la evaluación de la ansiedad somática, ansiedad cognitiva y la autoconfianza de los atletas de rugby Sub 18 y Sub 20 de los equipos nacionales de rugby portugués que participó, respectivamente, en U18 European Elite Campeonato y en el U20 Trophy World Rugby, comparando avanzados y defensas. Para la recolección de datos, utilizamos el CSAI-2 que evalúa la ansiedad cognitiva, la ansiedad somática y la autoconfianza. Los resultados mostraron parámetros medios más favorables para el grupo de atletas Sub-20. Sin embargo, sólo hubo diferencias significativas favorables para el equipo Sub-20 en el dominio de la autoconfianza, en un nivel general entre equipos y en las posiciones de avanzados.info:eu-repo/semantics/publishedVersio

Using Anthropometric Data and Physical Fitness Scores to Predict Selection in a National U19 Rugby Union Team

The purpose of this study was to compare measures of anthropometry characteristics and physical fitness performance between rugby union players (17.9 ± 0.5 years old) recruited (n = 39) and non-recruited (n = 145) to the Portuguese under-19 (U19) national team, controlling for their playing position (forwards or backs). Standardized anthropometric, physical, and performance assessment tests included players’ body mass and height, push up and pull-up test, squat test, sit- and-reach test, 20 m shuttle run test, flexed arm hang test, Sargent test, handgrip strength test, Illinois agility test, and 20-m and 50-m sprint test. Results showed that recruited forwards players had better agility scores (p = 0.02, ES = −0.55) than the non-recruited forwards, whereas recruited backs players had higher right (p < 0.01, ES = 0.84) and left (p = 0.01, ES = 0.74) handgrip strength scores than their counterparts. Logistic regression showed that better agility (for the forwards) and right handgrip strength scores (for the backs) were the only variables significantly associated with an increased likelihood of being recruited to the national team. In sum, these findings suggest that certain well- developed physical qualities, namely, agility for the forwards players and upper-body strength for the back players, partially explain the selection of U19 rugby players to their national team.info:eu-repo/semantics/publishedVersio

Intergenerational Transfer of Occupational Status in Portugal, 1850-1960: Unravelling Modernization Processes

This paper sets out to investigate the consequences of modernization processes as they took place in Portugal between 1850 and 1960 on the transfer of occupational status from father to son. Information from marriage registers in six municipalities in Portugal will be used

Thermal behavior of a BIPV combined with water storage: an experimental analysis

ABSTRACT: Buildings play an active role in the global energy consumption and are required to not only minimize their energy use, but also generate energy in a sustainable manner. The integration of renewable energies in building elements can improve their overall performance, as they are able to replace common construction materials, while offering both electrical and thermal energy. The scope of this paper is to present the first results of an experimental study of a Building-Integrated Photovoltaic system combined with a water storage tank (BIPV-WS), a combined integration not extensively studied yet. Both layers are separated by a ventilated air cavity, and the thermal behavior of the system was analyzed experimentally in real functioning conditions. The water tank performs as a thermal storage, maintaining a regular temperature of about 20-30 degrees C during a typical winter day of Lisbon for a period of 11 h. Moreover, through the ventilation of the air cavity, the heat provided by the solar panel was naturally recovered to the indoors of the building, while keeping the temperature high enough to heat up the water. During summer, the ventilated BIPV-WS enabled beneficial nocturnal heat loss while delaying diurnal space heating.info:eu-repo/semantics/publishedVersio

Variation in upper thermal tolerance among 19 species from temperate wetlands

Communities usually possess a multitude of interconnected trophic interactions within food webs. Their regulation generally depends on a balance between bottom-up and top-down effects. However, if sensitivity to temperature varies among species, rising temperatures may change trophic interactions via direct and indirect effects. We examined the critical thermal maximum (CTmax) of 19 species from temperate wetlands (insect predators, amphibian larvae, zooplankton and amphipods) and determined if they vary in their sensitivity to warming temperatures. CTmax differed between the groups, with predatory insects having higher CTmax than amphibians (both herbivorous larval anurans and predatory larval salamanders), amphipods and zooplankton. In a scenario of global warming, these differences in thermal tolerance may affect top-down and bottom-up processes, particularly considering that insect predators are more likely to maintain or improve their performance at higher temperatures, which could lead to increased predation rates on the herbivores in the food web. Further studies are needed to understand how the energy flows through communities, how species’ energy budgets may change and whether other physiological and behavioral responses (such as phenotypic plasticity and thermoregulation) can buffer or increase these changes in the top-down regulation of wetland food webs.U.S. National Science Foundation 0716149Ministerio de Ciencia e Innovación CGL2009-12767-C02-02Ministerio de Economía y Competitividad CGL201240246C0201, CGL2017-86924-

Extrusion of poly(vinylidene fluoride) recycled filaments : effect of the processing cycles on the degree of crystallinity and electroactive phase content

This study analyses the possibility of reprocessing used poly(vinylidene fluoride), PVDF, maintaining the main properties critical for its use in piezoelectric sensor/actuator applications. The influence of multiple reprocessing cycles of PVDF on crystallinity and ß-phase content fundamental for its electroactive behaviour, was studied. Nine reprocessing cycles were completed and it was found that the material preserved the characteristics required for its use as piezoelectric polymer without significant degradation.The authors thank the Portuguese Foundation for Science and Technology (FCT) (gs1) for financial support under Project Piezotex - PTDC (PTDC/CTM/108801/2008) and in the framework of the Strategic Project PEst-C/FIS/ UI607/20112011, PEst-C/CTM/LA0025/2011 and PEst-C/CTM/UI0264/2011. MPS thanks the FCT for financial support under grant SFRH/BD/70303/2010

Effect of the processing conditions on the mechanical and electrical properties of extruded conductive PP tape and filament

Polypropylene (PP) shows a number of desirable properties that make it a versatile material among thermoplastic polymers. Due to its low cost and density, it is an excellent resin for conductive polymer composites (CPCs).[1] CPCs mainly consist on a polymer matrix with incorporated carbonaceous fillers. These multifunctional materials are routinely employed in various commercial applications due to their good electrical conductivity, corrosion resistance, light weight and enhanced mechanical properties. [2] The filler content is the crucial aspect in conductive polymer composites fabrication: due to mechanical behaviour it must be as low as possible but enough to allow fulfilling the electrical requirements.[2] In this work commercial conductive master batch PP was extruded in the form of tape and filament using different processing conditions, namely different draw ratios and temperatures. In order to tailor the mechanical performance of the material, different several amounts of PP homopolymer were added to the commercial conductive resin. The results show that the amount of homopolymer directly influences mechanical and electrical performance of the material. Increasing homopolymer content yields a more stretchable, and mechanically resistant, material but, on the other hand, reduces its electrical conductivity. This study focuses on the optimization of the processing conditions and composition in order to tailor the mechanical and electrical properties of the material for specific applicationsFundação para a Ciência e a Tecnologia (FCT) - PTDC/CTM/108801/2008, POCI 2010, Pluriannual program