Identification of Segments of French Urban Public Transport with a Latent Class Frontier Model

This paper analyses technical efficiency of French urban public transport from 1995 to 2002 with unbalanced panel data. The latent class frontier model is used allowing the identification of different segments in the production frontier. We find that there are three statistically significant segments in the sample. Therefore, we conclude that no common transport policy can reach all of the transportation companies analysed, thereby requiring transport policies by segments.Urban public transport, stochastic production frontier, latent class model, technical efficiency, panel data.

Productivity Growth and Biased Technological Change in UK Airports

In this paper we estimate the total factor productivity of UK airports using a Malmquist index. Productivity change is factored into an index of efficiency change and an index of technological change. Technological change is further decomposed into indexes that measure the bias in the production of outputs, the bias in the employment of inputs, and the magnitude of the shift in the production frontier. Airports are ranked according to their productivity change for the period 2000-2005. The majority of UK airports did not improve their efficiency during the period. Economic implications are derived.UK airports; productivity growth; biased technological change; policy implications

Accounting for unobservables in production models:management and inefficiency

This paper explores the role of unobserved managerial ability in production and its relationship with technical efficiency. Previous analyses of managerial ability have been based on strong assumptions about its role in production or on the use of proxies. We avoid these limitations by introducing managerial ability as an unobserved random variable in a translog production function. The resulting empirical model can be estimated as a stochastic production frontier with random coefficients.Managerial ability, technical efficiency, production frontier, random coefficients model, maximum simulated likelihood.

Recent trends in homeownership

The homeownership rate began to trend upward in 1995 after years of being relatively constant, near 64 percent. This article describes recent changes in the share of U.S. housing that is owner-occupied and explores the reasons for the surprising rise over the past decade. Explanations that have been offered include demographics, low mortgage rates, changes in housing policy, and innovations in the mortgage financial market. Of all these explanations, the most plausible one is that innovations in the financial markets increased access to mortgage finance, mainly by reducing downpayment constraints and allowing younger people to buy homes.Home ownership

Comportamento eletrônico, magnético e estrutural da ludwigita Co3O2BO3

Orientador: Eduardo Granado Monteiro da SilvaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb WataghinResumo: Co3O2BO3 é um oxiborato de valência mista que cristaliza na estrutura ludwigite. Um experimento recente de difração de nêutrons indica íons Co3+ em um estado de baixo spin a temperaturas abaixo de ~ 40 K, enquanto dados de suscetibilidade magnética são mais consistentes com esses íons em um estado de spin alto acima de ~ 150 K. Uma investigação mais completa dos estados eletrônicos e magnéticos de Co é assim requerida. Para este fim foram realizadas medidas de absorção de raios X, difração de raios X, susceptibilidade magnética e resistividade-cc. Observamos anomalias na condutividade elétrica e nos parâmetros de rede Co3O2BO3, onde a borda de absorção K do Co parece responder a essas anomalias. As bordas de absorção L2,3 do Co indicam íons Co3+ em um estado de spin alto à temperatura ambiente. Além disso, o inverso da curva de susceptibilidade magnética desvia da lei de Curie-Weiss até temperaturas tão altas quanto ~ 550 K. Essas observações são interpretadas em termos de duas transições de ordenamento de carga, as quais são acompanhados por uma reacomodação dos parâmetros de rede, e um cruzamento de estados de spin alto e baixo nos ions de Co3+Abstract: Co3O2BO3 is a mixed valence oxyborate that crystallizes in the ludwigite structure. A recent neutron powder diffraction experiment indicates Co3+ ions in a low spin (LS) state at temperatures below ~ 40 K, while magnetic susceptibility data are more consistent with these ions in a high spin (HS) state above ~ 150 K. A more thorough investigation of the Co electronic and magnetic states is thus called for. To this end, X-ray absorption, X-ray diffraction, magnetic susceptibility, and dc-resistivity measurements were performed. We have observed anomalies in the electrical conductivity and in the lattice parameters of Co3O2BO3, where the Co K absorption edge seems to respond accordingly to these anomalies. The Co L2,3 absorption edges indicate Co3+ ions in a HS state at room temperature. In addition, the inverse of magnetic susceptibility curve deviates from the Curie-Weiss law up to temperatures as high as ~ 550 K. These observations are interpreted in terms of two charge ordering transitions, which are accompanied by a reaccommodation of the lattice parameters, and a Co3+ LS-HS spin state crossoverMestradoFísicaMestre em Física165818/2013-1CNP

Lysosomal storage diseases

Lysosomes are cytoplasmic organelles that contain a variety of different hydrolases. A genetic deficiency in the enzymatic activity of one of these hydrolases will lead to the accumulation of the material meant for lysosomal degradation. Examples include glycogen in the case of Pompe disease, glycosaminoglycans in the case of the mucopolysaccharidoses, glycoproteins in the cases of the oligosaccharidoses, and sphingolipids in the cases of Niemann-Pick disease types A and B, Gaucher disease, Tay-Sachs disease, Krabbe disease, and metachromatic leukodystrophy. Sometimes, the lysosomal storage can be caused not by the enzymatic deficiency of one of the hydrolases, but by the deficiency of an activator protein, as occurs in the AB variant of GM2 gangliosidosis. Still other times, the accumulated lysosomal material results from failed egress of a small molecule as a consequence of a deficient transporter, as in cystinosis or Salla disease. In the last couple of decades, enzyme replacement therapy has become available for a number of lysosomal storage diseases. Examples include imiglucerase, taliglucerase and velaglucerase for Gaucher disease, laronidase for Hurler disease, idursulfase for Hunter disease, elosulfase for Morquio disease, galsulfase for Maroteaux-Lamy disease, alglucosidase alfa for Pompe disease, and agalsidase alfa and beta for Fabry disease. In addition, substrate reduction therapy has been approved for certain disorders, such as eliglustat for Gaucher disease. The advent of treatment options for some of these disorders has led to newborn screening pilot studies, and ultimately to the addition of Pompe disease and Hurler disease to the Recommended Uniform Screening Panel (RUSP) in 2015 and 2016, respectively