Damping-Antidamping Effect on Comets Motion

We make an observation about Galilean transformation on a 1-D mass variable systems which leads us to the right way to deal with mass variable systems. Then using this observation, we study two-bodies gravitational problem where the mass of one of the bodies varies and suffers a damping-antidamping effect due to star wind during its motion. For this system, a constant of motion, a Lagrangian and a Hamiltonian are given for the radial motion, and the period of the body is studied using the constant of motion of the system. Our theoretical results are applied to Halley's comet.Comment: 19 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:0910.468

A vulnerability approach to the definition of the middle class

Measurement of the middle class has recently come to the center of policy debate in middle-income countries as they search for the potential engines of growth and good governance. This debate assumes, first, that there is a meaningful definition of class, and second, that thresholds that define relatively homogeneous groups in terms of pre-determined sociological characteristics can be found empirically. This paper aims at proposing a view of the middle class based on vulnerability to poverty. Following this approach the paper exploits panel data to determine the amount of comparable income -- associated with a low probability of falling into poverty -- which could define the lower bound of the middle class. The paper looks at absolute thresholds, challenging the view that people above the poverty line are actually part of the middle class. The estimated lower threshold is used in cross-section surveys to quantify the size and the evolution of middle classes in Chile, Mexico, and Peru over the past two decades. The first relevant feature relates to the fact that the proposed thresholds lie around the 60th percentile of the distribution. The evidence also shows that the middle class has increased significantly in all three countries, suggesting that a higher number of households face lower probabilities of falling into poverty than they did in the 1990s. There is an important group of people, however, which cannot be defined as middle class from this perspective, but are not eligible for poverty programs according to traditional definitions of poverty.Rural Poverty Reduction,Inequality,Regional Economic Development,Urban Partnerships&Poverty,Services&Transfers to Poor

Role Model Stories That Unite Children of Oaxacan Immigrants

Through my internship at Castroville Library Homework Center I endure power by telling stories to unite with children of Oaxacan immigrants while helping them with homework. Dacher Keltner power principles helped me have a trusting communication to learn the success and struggles in the children of Oaxacan immigrant’s education

The Decline in Inequality in Latin America: How Much, Since When and Why

Between 2000 and 2009, the Gini coefficient declined in 13 of 17 Latin American countries for which comparable data exist. The decline was statistically significant and robust to changes in the time interval, inequality measures and data sources. In depth country studies for Argentina, Brazil, Mexico and Peru suggest that there are two phenomena which underlie this trend: (i) a fall in the premium to skilled labor (as measured by returns to education); and (ii) higher and more progressive government transfers. The fall in the premium to skills results from a combination of supply and demand factors and, in Argentina and, to a lesser extent, in Brazil, from more active labor market policies as well.Income inequality, wage gap, government transfers, Latin America

The decline in inequality in Latin America: How much, since when and why

Between 2000 and 2009, the Gini coefficient declined in 13 of 17 Latin American countries for which comparable data exist. The decline was statistically significant and robust to changes in the time interval, inequality measures and data sources. In depth country studies for Argentina, Brazil, Mexico and Peru suggest that there are two phenomena which underlie this trend: (i) a fall in the premium to skilled labor (as measured by returns to education); and (ii) higher and more progressive government transfers. The fall in the premium to skills results from a combination of supply and demand factors and, in Argentina—and to a lesser extent in Brazil--, from more active labor market policies as well.Income inequality, wage gap, government transfers, Latin America.