The Buenos Aires water concession

The signing of a concession contract for the Buenos Aires water and sanitation system in December 1992, attracted worldwide attention, and caused considerable controversy in Argentina. It was one of the world's largest concessions, but the case was also interesting for other reasons. The concession was implemented rapidly, in contrast with slow implementation of privatization in Santiago, for example. And reform generated major improvements in the sector, including wider coverage, better service, more efficient company operations, and reduced waste. Moreover, the winning bid brought an immediate 26.9 percent reduction in water system tariffs. Consumers benefited from the system's expansion and from the immediate drop in real prices, which was only partly reversed by subsequent changes in tariffs, and access charges. And these improvements would probably not have occurred under public administration of the system. Still, the authors show information asymmetries, perverse incentives, and weak regulatory institutions could threaten the concession's sustainability. Opportunities for the company to act opportunistically - and the regulator, arbitrarily - exist, because of politicized regulation, a poor information base, serious flaws in the concession contract, a lumpy and ad hoc tariff system, and a general lack of transparency in the regulatory process. Because of these circumstances, public confidence in the process has eroded. The Buenos Aires concession shows how important transparent, rule-based decision-making is to maintain public trust in regulated infrastructure.Health Economics&Finance,Environmental Economics&Policies,Water Conservation,Water and Industry,Decentralization,Town Water Supply and Sanitation,Environmental Economics&Policies,Water and Industry,Water Supply and Sanitation Governance and Institutions,Water Conservation

Some aspects of the synchronization in coupled maps

Through numerical simulations we analyze the synchronization time and the Lyapunov dimension of a coupled map lattice consisting of a chain of chaotic logistic maps exhibiting power law interactions. From the observed behaviors we find a lower bound for the size $N$ of the lattice, independent of the range and strength of the interaction, which imposes a practical lower bound in numerical simulations for the system to be considered in the thermodynamic limit. We also observe the existence of a strong correlation between the averaged synchronization time and the Lyapunov dimension. This is an interesting result because it allows an analytical estimation of the synchronization time, which otherwise requires numerical simulations.Comment: 4 pages, 6 figure

Caracterização do carvão vegetal de Eucalyptus benthamii produzido em fornos rabo quente.

Resumo

Avaliação do poder calorífico da madeira de Eucalyptus benthamii (Maiden et Cambage) em função do teor de umidade.

Resumo

Balanço energético da produção de Eucalyptus benthamii em Guarapuava - PR.

CONBIEN

Uma viagem “No Mundo da Ciência” (Folha de S. Paulo/ 1947 a 1958): a história de um suplemento de ciência

Para entendermos a divulgação científica que é realizada, atualmente, é importante ampliarmos os aspectos históricos de sua constituição como campo de estudo e prática. Para isso, analisamos os textos publicados, pelo biologista do Instituto Biológico, um dos fundadores da SBPC e patrono da divulgação científica no Brasil, José Reis (1909-2002), na seção permanente de ciência "No Mundo da Ciência" criada no, então, jornal Folha da Manhã (atual Folha de S. Paulo). A análise de 344 artigos, no período de 1947-1958, pode evidenciar como as iniciativas de divulgação científica de forma mais organizada visaram à formação de um público educado cientificamente e constituírem-se em uma tendência para a consolidação do caráter público da ciência. O período de análise dos textos (1947-1958) é particularmente significativo, pois foi marcado pela mobilização da comunidade científica com a criação da SBPC (na qual José Reis foi um dos fundadores e integrante de seu Conselho Científico), do CNPq, da ideia da Fapesp, entre outros. A ênfase no período histórico do pós-guerra é explicada pela importância da ação do Estado e da pressão da própria comunidade científica pela institucionalização e profissionalização da ciência. A tentativa de inscrever a divulgação científica dentro de uma perspectiva histórica não se encerra na atuação do cientista-divulgador e dos textos analisados, no entanto, fica evidente a importância de seu trabalho na constituição do campo da popularização da ciência e do jornalismo científico promovidos atualmente

Mechanisms for Vascular Cell Adhesion Molecule-1 Activation of ERK1/2 during Leukocyte Transendothelial Migration

Background: During inflammation, adhesion molecules regulate recruitment of leukocytes to inflamed tissues. It is reported that vascular cell adhesion molecule-1 (VCAM-1) activates extracellular regulated kinases 1 and 2 (ERK1/2), but the mechanism for this activation is not known. Pharmacological inhibitors of ERK1/2 partially inhibit leukocyte transendothelial migration in a multi-receptor system but it is not known whether VCAM-1 activation of ERK1/2 is required for leukocyte transendothelial migration (TEM) on VCAM-1. Methodology/Principal Findings: In this study, we identified a mechanism for VCAM-1 activation of ERK1/2 in human and mouse endothelial cells. VCAM-1 signaling, which occurs through endothelial cell NADPH oxidase, protein kinase Ca (PKCa), and protein tyrosine phosphatase 1B (PTP1B), activates endothelial cell ERK1/2. Inhibition of these signals blocked VCAM-1 activation of ERK1/2, indicating that ERK1/2 is activated downstream of PTP1B during VCAM-1 signaling. Furthermore, VCAM-1-specific leukocyte migration under physiological laminar flow of 2 dynes/cm 2 was blocked by pretreatment of endothelial cells with dominant-negative ERK2 K52R or the MEK/ERK inhibitors, PD98059 and U0126, indicating for the first time that ERK regulates VCAM-1-dependent leukocyte transendothelial migration. Conclusions/Significance: VCAM-1 activation of endothelial cell NADPH oxidase/PKCa/PTP1B induces transient ERK1/2 activation that is necessary for VCAM-1-dependent leukocyte TEM

A new large cynodont from the Late Permian (Lopingian) of the South African Karoo Basin and its phylogenetic significance

The Karoo Basin of South Africa has the best global record of Lopingian (Late Permian) non-mammaliaform cynodonts, currently represented by five species. We describe Vetusodon elikhulu gen. et sp. nov., documented by four specimens from the Daptocephalus Assemblage Zone. With a basal skull length of ~18 cm, it is the largest Lopingian cynodont and is also larger than Induan representatives of the group. Vetusodon elikhulu has a cranial morphology that departs notably from that previously documented for Permo-Triassic cynodonts. It features a short and extremely wide snout, resembling that of the contemporaneous therocephalian Moschorhinus, and has large incisors and canines that contrast with the small unicusped postcanines, suggesting a more important role of the anterior dentition for feeding. The dentary is extremely long and robust, with the posterior margin located closer to the craniomandibular joint than in other Lopingian and Induan cynodonts (e.g. Thrinaxodon). The secondary palate morphology of V. elikhulu is unique, being short and incomplete and with the posterior portion of the maxilla partly covering the vomer. A phylogenetic analysis suggests that V. elikhulu is the sister taxon of Eucynodontia and thus the most derived of the Lopingian to Induan cynodonts yet discovered.Fil: Abdala, Nestor Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Gaetano, Leandro Carlos. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; ArgentinaFil: Smith, Roger M. H.. Evolutionary Studies Institute; SudáfricaFil: Rubidge, Bruce. Evolutionary Studies Institute; Sudáfric

MODELO EXPERIMENTAL DE GLOMERULONEFRITIS MEMBRANOSA INDUCIDA CON ALBUMINA BOVINA

El objetivo del presente trabajo fue diseñar un modelo experimental de Glomerulonefritis Membranosa (GM) en ratas Wistar, inducida con Seroalbúmina Bovina (BSA), y validarlo mediante la determinación de parámetros bioquímicos, histológicos, ultraestructurales y detección de inmunocomplejos por inmunofluorescencia (IF). Los animales del grupo experimental fueron inmunizados por vía subcutánea, con dosis de 3 mg c/u de BSA/PBS con adyuvante de Freund. Se efectuaron diferentes esquemas de inmunización. Cuando el título de anticuerpos fue ≥1/2, comenzó la administración diaria de 2 mg, por vía endovenosa de BSA/PBS, durante 15 días. Se evaluó la funcionalidad renal por la proteinuria; después de la 5° semana, desde su aparición, se determinó: depuración (clearance) de creatinina, uremia, proteinemia y perfil lipídico. Los dos riñones se usaron para estudios histológicos, ultraestructurales y detección de inmunocomplejos por IF. Los resultados mostraron que la inmunización fue efectiva con 5 R E S U M E N inoculaciones c/15 días. En los animales nefróticos la proteinuria, depuración (clearance) de creatinina, proteinemia , uremia y el perfil lipídico presentaron alteraciones significativas (p<0.0001). Al microscopio óptico se observó hipercelularidad, engrosamiento difuso de las membranas basales de los capilares glomerulares y diferentes grados de atrofia, esclerosis e hialinización de los glomérulos. Por IF se detectó inmunocomplejos IgG en el 100 % de los glomérulos. Ultraestructuralmente, se observaron depósitos subepiteliales electrodensos en la membrana basal engrosada, compatibles con inmunocomplejos . Se encontraron alteraciones en la estructura de los podocitos. En conclusión, los estudios bioquímicos, estructurales y ultraestructurales permitieron inferir la inducción de un síndrome nefrótico experimental. Concluimos que el protocolo utilizado tiene validez para la inducción de una glomerulonefritis membranosa en ratas Wistar