Firm Entry, Productivity Differentials and Turnovers in Import Substituting Markets: A study of the petrochemical industry in Colombia

This paper analyses plant entry, total factor productivity growth, average productivity level differentials and turnovers across Colombia's petrochemical industry for the 1974-1998 period. Results show that successful entrants shaped industry productivity and induced plant restructuring among incumbent plants. There is consistent plant heterogeneity across plant cohorts as well as across sub-markets within petrochemicals. Entry flows were steady increasing within plastics regardless of trade policy regimes. Survival rates are remarkably high and consistent over time in medium-size plants meaning that entrants adopted competitive post-entry strategies. Total factor productivity growth decomposition shows that the incumbent effect dominates the turnover effect. Market share reallocation among continuing plants constitutes an important source of productivity growth. Econometric results suggest that barriers to entry associated with plant technology licensing and dependence of imported raw materials deter entry while complementary market variables such as industry productivity levels, growth in housing construction, and fringe competition induce firm entry.Entry, Turnover, Total Factor Productivity, Petrochemical Industry

Corporate Valuation and Governance: Evidence from Colombia

We examine for the first time the association of different measures of ownership and control, and separation ratios with firm’s value and performance for 108 non-financial firms that traded their stock during the period 1998 to 2002. We found that large blockholders exert a positive influence upon firm’s valuation and performance, which validates the positive monitoring approach of large shareholders, but also found that this relation is not monotone implying that when separation of control and ownership tends to increase, a negative effect is exerted on firm’s valuation. Furthermore, we report first estimates of a survey of corporate governance practices conducted in 2004 for 43 Colombian non-financial companies. The index’s scores suggest that implementation of good governance in Colombian firms has been slow and poor as measured by the average of the Index that is below half the maximum attainable value. Regrettably, we did not find any support to recent theories that predict a positive association between good governance practices, measured by the CGI, and performance. At most there exists a positive relationship for sub-index but the results were not statistically significant in general.Ownership, Control, Corporate Governance, Colombia

Corporate Governance and Firm Valuation in Colombia

This paper studies the separation of ownership and control of 108 listed companies in Colombia from 1996 to 2002, finding that voting rights are greater than cash flow rights because of indirect ownership across firms. The paper also examines the association of various ownership and control measures and separation ratios with a firm’s value and performance for the same sample of companies that traded their stock from 1998 to 2002. Large blockholders were found to exert a positive influence upon a firm’s valuation and performance, which validates the positive monitoring approach of large shareholders, but this relationship is not monotonic. The paper further reports results from a 2004 survey which suggests that Colombian firms have been slow to improve their corporate governance practices.

Corporate Valuation and Governance: Evidence from Colombia

This paper examines for the first time the association of different ownership and control measures and separation ratios with a firm`s value and performance for 108 non-financial firms that traded their stock during the period 1998 to 2002. Large blockholders were found to exert a positive influence upon a firm`s valuation and performance, which validates the positive monitoring approach of large shareholders, but it was also found that this relationship is not monotonic, implying that when separation of control and ownership tends to increase, a negative effect is exerted on firm`s valuation. This paper also reports the first estimates of a survey of corporate governance practices conducted in 2004 for 43 Colombian non-financial companies. The corporate governance index`s (CGI) scores suggest that implementation of good governance in Colombian firms has been slow and poor, as measured by an index average that is below half the maximum attainable value. Regrettably, it was not possible to find any support to recent theories that predict a positive association between good governance practices -as measured by the CGI - and performance. At most, there exists a positive relationship for the sub-index, but the results were not statistically significant in general.

Análisis de la reacción hidrógeno-aire mediante métodos de perturbaciones singulares

Cuando en el estudio de las reacciones químicas se da simplemente la reacción global, se esta haciendo realmente una descripción muy parcial de la reacción química. Dar la reacción global es dar las proporciones en que intervienen los reactantes en la reacción, asi como las proporciones en que aparecen los productos. Implicitamente se supone que la reaccion tiene lugar adiabaticamente, que el proceso es a presion constante y que se parte de las condiciones standard. Se supone, además, que los productos se encuentran finalmente en equilibrio termodinamico. Asi, cuando se escribe que la reacció

Einstein-Maxwell-scalar black holes: the hot, the cold and the bald

The phenomenon of spontaneous scalarisation of charged black holes (BHs) has recently motivated studies of various Einstein-Maxwell-scalar models. Within these models, different classes of BH solutions are possible, depending on the non-minimal coupling function $f(\phi)$, between the scalar field and the Maxwell invariant. Here we consider the class wherein both the (bald) electrovacuum Reissner-Nordstr\"om (RN) BH and new scalarised BHs co-exist, and the former are never unstable against scalar perturbations. In particular we examine the model, within this subclass, with a quartic coupling function: $f(\Phi) = 1+\alpha \Phi ^4$. The domain of existence of the scalarised BHs, for fixed $\alpha$, is composed of two branches. The first branch (cold scalarised BHs) is continuously connected to the extremal RN BH. The second branch (hot scalarised BHs) connects to the first one at the minimum value of the charge to mass ratio and it includes overcharged BHs. We then assess the perturbative stability of the scalarised solutions, focusing on spherical perturbations. On the one hand, cold scalarised BHs are shown to be unstable by explicitly computing growing modes. The instability is quenched at both endpoints of the first branch. On the other hand, hot scalarised BHs are shown to be stable by using the S-deformation method. Thus, in the spherical sector this model possesses two stable BH local ground states (RN and hot scalarised). We point out that the branch structure of BHs in this model parallels the one of BHs in five dimensional vacuum gravity, with [Myer-Perry BHs, fat rings, thin rings] playing the role of [RN, cold scalarised, hot scalarised] BHs.Comment: 12 pages, 6 figure

On diffusive supersonic combustion (chemical kinetic effects in diffusive supersonic combustion)

Simple analytical methods are presented for the analysis of chemical kinetic effects in supersonic combustion. Three different regions are shown to occur in supersonic diffusive combustion. The first region is close to the injector exit, where the flow may be considered frozen for the main reacting species and where the radical concentration is being built up. This is the ignition delay region. A simplified kinetic scheme of the H2-air reaction is deduced for this region. The linear differential equation giving the H concentration has been discussed and integrated in a representative case. In terms of this solution the limits of the ignition region may be determined. Far from the injector exit the flow is close to chemical equilibrium. The reaction region is very thin, so that convection effects may be neglected. Then the governing equations reduce to ordinary differential equations, that may be integrated by using an integral method. In this way, deviations from equilibrium may be determined in terms of the reaction kinetics. An extension of the integral method, developed for the analysis of the near-equilibrium region is proposed for the study of the transition region

Nuestra experiencia con la enfermedad de Freiberg

Analizamos una serie de 34 pacientes, 9 varones y 25 mujeres, con enfermedad de Freiberg, detallando su localización y grado evolutivo en el momento del diagnóstico. Clínicamente la severidad del cuadro fue muy variable, y con frecuencia discordante con la imagen radiológica. Tan solo en 5 pacientes fue necesario el tratamiento quirúrgico. No se pudo detectar un factor etiológico claro y único, existiendo casos con y sin antecedentes traumáticos. Se describe la evolución radiológica de esta enfermedad. La RMN permite de forma precoz, detectar las anomalías óseas en las fases más iniciales.We analyze a series of 34 patients, 9 males and 25 females, with Freiberg's disease, detailing their location and severity at moment of the diagnosis. Clinically the severity of disease was variable, and frequently discordant with the radiological image. Only in 5 patients was necessary the surgical treatment. There was no etiologic factor clearly found in any of the cases, with and without traumatic precedents. We describe the radiological pattern of this disease. The MRI permits at early stage detection of bone anomalies

Motor Competence Assessment (MCA) Scoring Method

The Motor Competence Assessment (MCA) is a quantitative test battery that assesses motor competence across the whole lifespan. It is composed of three sub-scales: locomotor, stability, and manipulative, each of them assessed by two different objectively measured tests. The MCA construct validity for children and adolescents, having normative values from 3 to 23 years of age, and the configural invariance between age groups, were recently established. The aim of this study is to expand the MCA’s development and validation by defining the best and leanest method to score and classify MCA sub-scales and total score. One thousand participants from 3 to 22 years of age, randomly selected from the Portuguese database on MC, participated in the study. Three different procedures to calculate the sub-scales and total MCA values were tested according to alternative models. Results were compared to the reference method, and Intraclass Correlation Coefficient, Cronbach’s Alpha, and Bland–Altman statistics were used to describe agreement between the three methods. The analysis showed no substantial differences between the three methods. Reliability values were perfect (0.999 to 1.000) for all models, implying that all the methods were able to classify everyone in the same way. We recommend implementing the most economic and efficient algorithm, i.e., the configural model algorithm, averaging the percentile scores of the two tests to assess each MCA sub-scale and total scores.4811-99FE-2ECD | Luis Paulo RodriguesN/