Study of rotation curves of spiral galaxies with a scalar field dark matter model

In this work we study rotation curves of spiral galaxies using a model of dark matter based on a scalar-tensor theory of gravity. We show how to estimate the scalar field dark matter parameters using a sample of observed rotation curves.Comment: 6 pages, 2 figures. arXiv admin note: substantial text overlap with arXiv:1112.520

Do Unprejudiced Societies Need Equal Opportunity Legislation?

To what extent should banks, insurance companies and employers be allowed to use personal information about the people whom they lend to, insure or employ in setting the terms of the contract? Even when different treatment is motivated by profit not prejudice, banning discrimination (when combined with mandatory protection against failure) may well be the best way of effecting redistribution of income. Unlike income taxation, this policy achieves its goals without much adverse effect on incentives. Public provision of low-powered incentive contracts issued on generous terms is also a potent instrument of efficient redistribution. This is true even if the government cannot observe type but the private sector can.equal opportunities, incentive contracts, asymmetric information, distribution

Guess the score, fostering collective intelligence in the class

This paper proposes the use of serious games as a tool to enhance collective intelligence of undergraduate and graduate students. The development of social skills of individuals in a group is related to the performance of the collective intelligence of the group manifested through the shared and collaborative development of intellectual tasks [1]. Guess the Score GS, is a serious game implemented by means of an online tool, created to foster the development, collaboration and engagement of students. It's has been designed with the intention of facilitating the development of individual’s social skills in a group in order to promote education of collective intelligence. This paper concludes that the design of learning activities using serious games as a support tool in education, generate awareness about of utilities of gaming in the collective learning environment and the fostering of collective intelligence education.Postprint (published version

Productivity in economies with financial frictions: facts and a theory

We document and account for two facts regarding the relation between international interest rates and total factor productivity (TFP) in a sample of developing countries. First, there is a negative correlation between both variables at quarterly frequency. Second, the share of agricultural labor and interest rates are positively correlated, whereas the share of agricultural labor and TFP are negatively correlated. Manufacturing labor shows opposite correlations. These relationships are particularly strong in the aftermath of financial crises. We then construct a model in which the presence of costly intermediation can produce such relationships. We show that, after increases in interest rates, a requirement to intermediate factors of production in high productivity sectors, like manufacturing, causes resources to leave these sectors. Resources end up in low productivity sectors, like agriculture, where intermediation is cheaper. This lowers aggregate productivity. We show that the channel we identify is quantitatively important in the case of Korea after the 1997 financial crisis. Keywords; small open economy, financial intermediation, total factor productivity

Spontaneous symmetry breaking, and strings defects in hypercomplex gauge field theories

Inspired by the appearance of split-complex structures in the dimensional reduction of string theory, and in the theories emerging as byproducts, we study the hyper-complex formulation of Abelian gauge field theories, by incorporating a new complex unit to the usual complex one. The hypercomplex version of the traditional Mexican hat potential associated with the $U(1)$ gauge field theory, corresponds to a {\it hybrid} potential with two real components, and with $U(1)\times SO(1,1)$ as symmetry group. Each component corresponds to a deformation of the hat potential, with the appearance of a new degenerate vacuum. Hypercomplex electrodynamics will show novel properties, such as the spontaneous symmetry breaking scenarios with running masses for the vectorial and scalar Higgs fields, and the Aharonov-Bohm type strings defects as exact solutions; these topological defects may be detected only by quantum interference of charged particles through gauge invariant loop integrals. In a particular limit, the {\it hyperbolic} electrodynamics does not admit topological defects associated with continuous symmetriesComment: 40 page

Geomagnetic effects on cosmic ray propagation under different conditions for Buenos Aires and Marambio, Argentina

The geomagnetic field (Bgeo) sets a lower cutoff rigidity (Rc) to the entry of cosmic particles to Earth which depends on the geomagnetic activity. From numerical simulations of the trajectory of a proton using different models for Bgeo (performed with the MAGCOS code), we use backtracking to analyze particles arriving at the location of two nodes of the net LAGO (Large Aperture Gamma ray burst Observatory) that will be built in the near future: Buenos Aires and Marambio (Antarctica), Argentina. We determine the asymptotic trajectories and the values of Rc for different incidence directions, for each node. Simulations were done using several models for Bgeo that emulate different geomagnetic conditions. The presented results will help to make analysis of future observations of the flux of cosmic rays done at these two LAGO nodes.Comment: 9 page