Has long become longer or short become shorter? Evidence from a censored quantile regression analysis of the changes in the distribution of U.S. unemployment duration

There is conflicting evidence regarding the recent evolution of unemployment duration in the U.S. In this study we rely on censored quantile regression methods to analyze the changes in the US unemployment duration distribution. We employed the decomposition method proposed by Machado and Mata (2003) to disentangle the contribution of the changes generated by the covariate distribution and by the conditional distribution and adapted it to a duration analysis framework.The data used in this inquiry are taken from the nationally representative Displaced Worker Survey of 1988 and 1998. We provide evidence that the unemployment duration distribution shifted leftward. The main driving force behind that shift was the sharp leftward move in the unemployment rate distribution. This force was partially counteracted by the ageing of the displaced population, the striking absence of impact from being displaced via a plant shutdown, and the higher sensitivity of unemployment duration to unemployment ratesQuantile Regression, Duration Analysis, Unemployment Duration, Counterfactual Decomposition

Market Penetration and Late Entry in Mobile Telephony

We consider some two dynamic models of entry in mobile telephony, with and without strategic pricing, and taking into account market penetration at entry, locked-in consumers and tariff-mediated network externalities. We show that on/off-net differentials may reduce the possibility of entry if incumbents are large, while they have no long-run effects if there are no locked-in consumers, or reduce the difference in subscriber numbers in their presence. Asymmetric fixedto- mobile or mobile-to-mobile termination rates increase (decrease) market share and profit of the network with the higher (lower) rate. While the fixed-to-mobile waterbed effect is not full at the network level, it will be full in the aggregate

Incentives to Invest and to Give Access to Non-Regulated Next Generation Networks

We analyze the incentives of a telecommunications incumbent to invest and give access to a downstream entrant to a next generation network, NGN. We model the industry as a duopoly, where a vertically integrated incumbent and a downstream entrant, that requires access to the incumbent's network, compete on Hotelling's line. The incumbent can invest in the deployment of a NGN that improves the quality of the retail services. Access to the old network is regulated, but access to the NGN is not. If the innovation is drastic, the incumbent always invests in the NGN, but does not give access to the entrant. If the innovation is non-drastic and if the access price to the old network is low, the incumbent voluntarily gives access to the NGN. If the innovation is non-drastic, there is no monotonic relation between the access price to the old network and the incumbent's incentives to invest. A regulatory moratorium emerges as socially optimal, if the innovation is large but non-drastic. We also analyze the case where both rms can invest in the deployment of a NGN

Deriving water quality parameters using sentinel-2 imagery: A case study in the Sado Estuary, Portugal

Monitoring water quality parameters and their ecological effects in transitional waters is usually performed through in situ sampling programs. These are expensive and time-consuming, and often do not represent the total area of interest. Remote sensing techniques offer enormous advantages by providing cost-effective systematic observations of a large water system. This study evaluates the potential of water quality monitoring using Sentinel-2 observations for the period 2018-2020 for the Sado estuary (Portugal), through an algorithm intercomparison exercise and time-series analysis of different water quality parameters (i.e., colored dissolved organic matter (CDOM), chlorophyll-a (Chl-a), suspended particulate matter (SPM), and turbidity). Results suggest that Sentinel-2 is useful for monitoring these parameters in a highly dynamic system, however, with challenges in retrieving accurate data for some of the variables, such as Chl-a. Spatio-temporal variability results were consistent with historical data, presenting the highest values of CDOM, Chl-a, SPM and turbidity during Spring and Summer. This work is the first study providing annual and seasonal coverage with high spatial resolution (10 m) for the Sado estuary, being a key contribution for the definition of effective monitoring programs. Moreover, the potential of remote sensing methodologies for continuous water quality monitoring in transitional systems under the scope of the European Water Framework Directive is briefly discussed.Fil: Sent, Giulia. Universidade Nova de Lisboa; PortugalFil: Biguino, Beatriz. Universidade Nova de Lisboa; PortugalFil: Favareto, Luciane. Universidade Nova de Lisboa; PortugalFil: Cruz, Joana. Universidade Nova de Lisboa; PortugalFil: Sá, Carolina. Universidade Nova de Lisboa; PortugalFil: Dogliotti, Ana Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Palma, Carla. Instituto Hidrográfico; PortugalFil: Brotas, Vanda. Universidade Nova de Lisboa; PortugalFil: Brito, Ana C.. Universidade Nova de Lisboa; Portuga

VIII Coloquio Ibérico de Geografía : Lisboa (Portugal), 30 de setembre al 2 d'octubre de 1999

Organitzat per la Universidade Nova de Lisboa, va tenir lloc a Lisboa el VIII Coloquio Ibérico de Geografía. L'objectiu de la trobada era donar a conèixer els treballs d'investigació que porten a terme geògrafs i geògrafes espanyols i portuguesos i establir un àmbit de reflexió entre les persones participants.Organizado por la Universidade Nova de Lisboa, tuvo lugar en Lisboa el VIII Coloquio Ibérico de Geografía. El objetivo del encuentro era dar a conocer los trabajos de investigación que llevan a cabo geógrafos y geógrafas españoles y portugueses y establecer un ámbito de reflexión entre las personas participantes.Organisé par la Universidade Nova de Lisboa, le VIIIème Colloque Ibérique de Géographie a eu lieu à Lisbonne. L'objectif était connaitre et réflechir sur les travails de recherche des géographes espagnols et portugais et d'établir une atmosphère de réflexion entre les participants.The VIIIth Iberian Geographical Congress was held at the Universidade Nova de Lisboa; the goal of the congress was to know and discuss the research that Spanish and Portuguese geographers are doing at this moment

Market Penetration and Late Entry in Mobile Telephony

We consider some two dynamic models of entry in mobile telephony, with and without strategic pricing, and taking into account market penetration at entry, locked-in consumers and tariff-mediated network externalities. We show that on/off-net differentials may reduce the possibility of entry if incumbents are large, while they have no long-run effects if there are no locked-in consumers, or reduce the difference in subscriber numbers in their presence. Asymmetric fixedto- mobile or mobile-to-mobile termination rates increase (decrease) market share and profit of the network with the higher (lower) rate. While the fixed-to-mobile waterbed effect is not full at the network level, it will be full in the aggregate

Substrate-dependent modulation of the enzymatic catalytic activity: Reduction of nitrate, chlorate and perchlorate by respiratory nitrate reductase from Marinobacter hydrocarbonoclasticus 617

The respiratory nitrate reductase complex (NarGHI) from Marinobacter hydrocarbonoclasticus 617 (Mh, formerly Pseudomonas nautica 617) catalyzes the reduction of nitrate to nitrite. This reaction is the first step of the denitrification pathway and is coupled to the quinone pool oxidation and proton translocation to the periplasm, which generates the proton motive force needed for ATP synthesis. The Mh NarGH water-soluble heterodimer has been purified and the kinetic and redox properties have been studied through in-solution enzyme kinetics, protein film voltammetry and spectropotentiometric redox titration. The kinetic parameters of Mh NarGH toward substrates and inhibitors are consistent with those reported for other respiratory nitrate reductases. Protein film voltammetry showed that at least two catalytically distinct forms of the enzyme, which depend on the applied potential, are responsible for substrate reduction. These two forms are affected differentially by the oxidizing substrate, as well as by pH and inhibitors. A new model for the potential dependence of the catalytic efficiency of Nars is proposed.Fil: Marangon, Jacopo. Universidade Nova de Lisboa; PortugalFil: Paes De Sousa, Patrícia M.. Universidade Nova de Lisboa; PortugalFil: Moura, Isabel. Universidade Nova de Lisboa; PortugalFil: Brondino, Carlos Dante. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Moura, José J. G.. Universidade Nova de Lisboa; PortugalFil: González, Pablo J.. Universidade Nova de Lisboa; Portuga

Incentives to Invest and to Give Access to Non-Regulated Next Generation Networks

We analyze the incentives of a telecommunications incumbent to invest and give access to a downstream entrant to a next generation network, NGN. We model the industry as a duopoly, where a vertically integrated incumbent and a downstream entrant, that requires access to the incumbent's network, compete on Hotelling's line. The incumbent can invest in the deployment of a NGN that improves the quality of the retail services. Access to the old network is regulated, but access to the NGN is not. If the innovation is drastic, the incumbent always invests in the NGN, but does not give access to the entrant. If the innovation is non-drastic and if the access price to the old network is low, the incumbent voluntarily gives access to the NGN. If the innovation is non-drastic, there is no monotonic relation between the access price to the old network and the incumbent's incentives to invest. A regulatory moratorium emerges as socially optimal, if the innovation is large but non-drastic. We also analyze the case where both rms can invest in the deployment of a NGN

Kinetic and structural studies of aldehyde oxidoreductase from Desulfovibrio gigas reveal a dithiolene-based chemistry for enzyme activation and inhibition by H2O2

Mononuclear Mo-containing enzymes of the xanthine oxidase (XO) family catalyze the oxidative hydroxylation of aldehydes and heterocyclic compounds. The molybdenum active site shows a distorted square-pyramidal geometry in which two ligands, a hydroxyl/water molecule (the catalytic labile site) and a sulfido ligand, have been shown to be essential for catalysis. The XO family member aldehyde oxidoreductase from Desulfovibrio gigas (DgAOR) is an exception as presents in its catalytically competent form an equatorial oxo ligand instead of the sulfido ligand. Despite this structural difference, inactive samples of DgAOR can be activated upon incubation with dithionite plus sulfide, a procedure similar to that used for activation of desulfo-XO. The fact that DgAOR does not need a sulfido ligand for catalysis indicates that the process leading to the activation of inactive DgAOR samples is different to that of desulfo-XO. We now report a combined kinetic and X-ray crystallographic study to unveil the enzyme modification responsible for the inactivation and the chemistry that occurs at the Mo site when Dg AOR is activated. In contrast to XO, which is activated by resulfuration of the Mo site, DgAOR activation/inactivation is governed by the oxidation state of the dithiolene moiety of the pyranopterin cofactor, which demonstrates the non-innocent behavior of the pyranopterin in enzyme activity. We also showed that Dg AOR incubation with dithionite plus sulfide in the presence of dioxygen produces hydrogen peroxide not associated with the enzyme activation. The peroxide molecule coordinates to molybdenum in a η2 fashion inhibiting the enzyme activity.Fil: Marangon, Jacopo. Universidade Nova de Lisboa; PortugalFil: Correia, Hugo D.. Universidade Nova de Lisboa; PortugalFil: Brondino, Carlos Dante. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moura, José J. G.. Universidade Nova de Lisboa; PortugalFil: Romão, Maria J.. Universidade Nova de Lisboa; PortugalFil: González, Pablo Javier. Universidade Nova de Lisboa; Portugal. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Santos Silva, Teresa. Universidade Nova de Lisboa; Portuga

Sobre “Monumentalidade e Espaço Públic Lourenço Marques (1930-1940)” de Gerbert Verheij

El artículo reproduce la intervención del profesor Abreu, en el jurado de evaluación de la tesis del master en Historia del Arte, “Monumentalidade e Espaço Público em Lourenço Marques (1930-1940)” de Gerbert Verheij realizada en la Facutad de Ciencias Sociales y Humanas de la Universidade Nova de Lisboa el 3 de Enero de 2012El artículo reproduce la intervención del profesor Abreu, en el jurado de evaluación de la tesis del master en Historia del Arte, “Monumentalidade e Espaço Público em Lourenço Marques (1930-1940)” de Gerbert Verheij realizada en la Facutad de Ciencias Sociales y Humanas de la Universidade Nova de Lisboa el 3 de Enero de 2012This article reproduces the reasoning by Prof. Abreu, on the jury to evaluate the master thesis in History of Art, “Monumentality and Public Space in Lourenço Marques (1930-1940)” by Gerbert Verheij, held in Faculty of Social Sciences and Humanities at the Universidade Nova de Lisboa on January 3, 201