Inflated Beta Distributions

This paper considers the issue of modeling fractional data observed in the interval [0,1), (0,1] or [0,1]. Mixed continuous-discrete distributions are proposed. The beta distribution is used to describe the continuous component of the model since its density can have quite diferent shapes depending on the values of the two parameters that index the distribution. Properties of the proposed distributions are examined. Also, maximum likelihood and method of moments estimation is discussed. Finally, practical applications that employ real data are presented.Comment: 15 pages, 4 figures. Submitted to Statistical Paper

The Indirect Effects of Conditional Cash Transfer Programs: An Empirical Analysis of Familias En Accion

Conditional cash transfer (CCT) programs have become the most important social policy in Latin America, and their influence has spread to countries around the world. A number of studies provide strong evidence of the positive impacts of these programs on the main targeted outcomes, education and health, and have proved successful in other outcomes such as nutrition, household income, and child labor. As we expect CCT programs to remain a permanent aspect of social policy for the foreseeable future, demand for evidence of the indirect effects of CCT programs has grown beyond the initial emphasis of these programs. My research pays particular attention to these relevant but unintended outcomes, which have been discussed less extensively in the literature. Familias en Accion (FA), a CCT program in Colombia, started operating in 2002 and has benefited approximately 1,500,000 households since its beginning. The results of the program’s evaluation survey, representative of poor rural households in Colombia, are a very good source or investigating not only the unintended effects of the program but also the microeconomic behavior of poor households and social policy issues in the country. Using a panel dataset from FA, I address three empirical policy questions: (i) to what extent is consumption of beneficiary households better insured against income shocks? (ii) has the program displaced child labor as a risk-coping instrument?, and (iii) are there any incentive effects of the cash transfers and the associated conditionalities on the labor supply of adults in recipient households? Each of my research questions is addressed separately; however, the results, taken together, can be informative in understanding the safety net value of the program and their potentialities to reduce poverty in the long term. I find that the program serves as an instrument for consumption smoothing. In particular, FA is effective in protecting food consumption, but not nonfood consumption, and it reduces consumption fluctuations in response to idiosyncratic shocks but not to covariate shocks. Results also reveal that FA works as insurance for the schooling of the poor but is not able to completely displace child labor. Finally, the results also show that beneficiary mothers are devoting more time to household chores and that girls and female adult labor are complementary. Male labor supply has increased while boys have increased leisure time as a response to the program

Large cities are less efficient for sustainable transport: The ABC of mobility

The distance travelled by car in a city has many negative impacts on its population, including pollution, noise and the use of space. Yet, quantifying the motorisation of urban mobility is a serious challenge, particularly across cities of different regions. Here we model the number of kilometres travelled by different modes of transport in a city by aggregating active mobility (A), public transport (B) and cars (C), thus expressing the modal share of a city by its ABC triplet. Data for over 800 cities across over 60 countries is used to model kilometres travelled by car and its relationship with city size. Our findings suggest that although public transport is more prominent in large cities, it is insufficient to reduce the distance travelled by car users within the city and, ultimately, their emissions. For cities outside the US, results show that although the proportion of journeys by car decreases in larger cities, distances become more prolonged, thus experiencing more distance travelled by car. When a city doubles its size, it has 87\% more car journeys, but they are 41% longer, thus experiencing 2.6 times more vehicle kilometres travelled. Further, by matching cities of similar size inside and outside the US, we estimate that cities in the US have 2.3 times more vehicle kilometres travelled than cities elsewhere.Comment: 14 pages, 6 figure

Validación de un instrumento de medición de ambiente escolar para docentes Colombianos

Este estudio explora la validez y fiabilidad de un instrumento de medición del ambiente escolar suministrado a 3610 docentes de las Instituciones Educativas oficiales de la ciudad de Medellín – Colombia en 2011. El análisis factorial exploratorio multinivel permitió establecer que a través de 20 reactivos el instrumento evalúa cuatro dimensiones de ambiente escolar a nivel individual: comunicación de la Institución Educativa hacia los docentes y comunicación de los docentes hacia los padres, nivel de participación en las decisiones de la Institución Educativa, respeto-seguridad emocional y expectativas académicas. A nivel grupal, los mismos reactivos permiten medir una dimensión general de ambiente escolar. Por tanto, los resultados sugieren que el instrumento permite establecer diferencias entre Instituciones Educativas en términos de ambiente escolar.This study explores the validity and reliability of a school environment instrument supplied to 3160 teachers from Medellin – Colombia public schools in 2011. The multilevel factorial analysis allowed establishing that through 20 reactives, the instrument evaluates four school environment dimensions at individual level: communication from the school to the teachers and communication from the teachers to the parents, participation level into the school decisions, respect-emotional security and academic expectations. At the group level, the same reactives allowed measuring a general school environment dimension. Therefore, results suggested the instrument permits to establish differences between schools in school environment terms

Patient centred diagnosis: sharing diagnostic decisions with patients in clinical practice.

Patient centred diagnosis is best practised through shared decision making; an iterative dialogue between doctor and patient, whichrespects a patient’s needs, values, preferences, and circumstances. Shared decision making for diagnostic situations differs fundamentally from that for treatment decisions. This has important implications when considering its practical application. The nature of dialogue should be tailored to the specific diagnostic decision; scenarios with higher stakes or uncertainty usually require more detailed conversation

Size polymorphism and low sequence diversity in the locus encoding the Plasmodium vivax rhoptry neck protein 4 (PvRON4) in Colombian isolates

Background: Designing a vaccine against Plasmodium vivax has focused on selecting antigens involved in invasion mechanisms that must have domains with low polymorphism for avoiding allele-specific immune responses. The rhoptry neck protein 4 (RON4) forms part of the tight junction, which is essential in the invasion of hepatocytes and/or erythrocytes; however, little is known about this locus’ genetic diversity. Methods: DNA sequences from 73 Colombian clinical isolates from pvron4 gene were analysed for characterizing their genetic diversity; pvron4 haplotype number and distribution, as well as the evolutionary forces determining diversity pattern, were assessed by population genetics and molecular evolutionary approaches. Results: ron4 has low genetic diversity in P. vivax at sequence level; however, a variable amount of tandem repeats at the N-terminal region leads to extensive size polymorphism. This region seems to be exposed to the immune system. The central region has a putative esterase/lipase domain which, like the protein’s C-terminal fragment, is highly conserved at intra- and inter-species level. Both regions are under purifying selection. Conclusions: pvron4 is the locus having the lowest genetic diversity described to date for P. vivax. The repeat regions in the N-terminal region could be associated with immune evasion mechanisms while the central region and the C-terminal region seem to be under functional or structural constraint. Bearing such results in mind, the PvRON4 central and/or C-terminal portions represent promising candidates when designing a subunit-based vaccine as they are aimed at avoiding an allele-specific immune response, which might limit vaccine efficacy. © 2016 The Author(s)