A direct comparison of the performance of public-private partnerships with that of traditional contracting / Una comparación directa del desempeño de una CPP con el modelo tradicional de contratación pública / Uma comparação direta do desempenho de uma PPP com o modelo tradicional de contratação pública

Abstract This paper assesses the city of Belo Horizonte's experience building school infrastructure through public-private partnerships (PPPs). Between 2009 and 2015, Belo Horizonte built very similar schools using both PPPs and traditional public contracting (TPC). As the choice of mode of contracting was unrelated to our outcomes of interest, the experience constitutes a quasi-experiment that allows for a simple and direct comparison of PPPs to TPC. We examine construction- and operation-phase outcomes measured using administrative data and a survey of school administrators. We find that schools constructed under the PPP contracting model outperformed those built using TPCs in most outcomes.

Resumen Este artículo evalúa la experiencia del municipio de Belo Horizonte en la construcción y operación de infraestructura escolar a través de una Colaboración Público-Privada (CPP). Entre 2009 y 2015, Belo Horizonte construyó escuelas similares usando tanto CPPs como el modelo tradicional de contratación pública (MTCP). Dado que la elección del modelo de contratación no tenía relación causal con los resultados evaluados, se puede afirmar que esa experiencia constituye un cuasi experimento que permite la comparación simple y directa de las CPPs con el MTCP. Evaluamos los principales resultados en las etapas de construcción y operación usando datos administrativos sumistrados por la alcaldía y con cuestionario aplicado a los directores de las escuelas. El artículo muestra que las escuelas construidas en el modelo de CPP tuvieron un desempeño mejor que las que usaron el MTCP.

Resumo Este artigo avalia a experiência do município de Belo Horizonte na construção e operação de infraestrutura escolar por meio de Parcerias Público-Privadas (PPPs). Entre 2009 e 2015, Belo Horizonte construiu escolas similares usando tanto PPPs como o modelo tradicional de contratação pública (MTCP). Dado que a escolha do modelo de contratação não tinha relação causal direta com os resultados avaliados, pode-se afirmar que essa experiência constitui um quasi experimento que permite a comparação simples e direta das PPPs com o MTCP. Avaliamos os principais resultados nas fases de construção e operação usando dados administrativos fornecidos pela prefeitura e com questionário aplicado aos diretores das escolas. O artigo mostra que as escolas construídas no modelo de PPP tiveram um desempenho melhor do que as que usaram o MTCP.

Phosphate diester hydrolysis and DNA damage promoted by new cis-aqua/hydroxy copper(II) complexes containing tridentate imidazole-rich ligands.

The tridentate Schiff base [(2-(imidazol-4-yl)ethyl)(1-methylimidazol-2-yl)methyl)imine (HISMIMI) and its reduced form HISMIMA were synthesized and characterized, as well their mononuclear cis-dihalo copper(II) complexes 1 and 2, respectively. In addition, the dinuclear [CuII(mu-OH)2CuII](2+) complexes (3) and (4) obtained from complexes 1 and 2, respectively, were also isolated and characterized by several physicochemical techniques, including magnetochemistry, electrochemistry, and EPR and UV-vis spectroscopies. The crystal structures of 1 and 2 were determined by X-ray crystallography and revealed two neutral complexes with their tridentate chelate ligands meridionally coordinated. Completing the coordination spheres of the square-pyramidal structures, a chloride ion occupies the apical position and another is bonded in the basal plane. In addition, complexes 1 and 2 were investigated by infrared, electronic, and EPR spectroscopies, cyclic voltammetry, and potentiometric equilibrium studies. The hydrolytic activity on phosphate diester cleavage of 1 and 2 was investigated utilizing 2,4-BDNPP as substrate. These experiments were carried out at 50 degrees C, and the data treatment was based on the Michaelis-Menten approach, giving the following kinetic parameters (complex 1/complex 2): vmax (mol L(-1) s(-1))=16.4x10(-9)/7.02x10(-9); KM (mol L(-1))=17.3x10(-3)/3.03x10(-3); kcat (s(-1))=3.28x10(-4)/1.40x10(-4). Complex 1 effectively promoted the hydrolytic cleavage of double-strand plasmid DNA under anaerobic and aerobic conditions, with a rate constant of 0.28 h(-1) for the decrease of form I, which represents about a 10(7) rate increase compared with the estimated uncatalyzed rate of hydrolysis.