Palatini approach to modified f(R) gravity and its bi-metric structure

f(R) gravity theories in the Palatini formalism has been recently used as an alternative way to explain the observed late-time cosmic acceleration with no need of invoking either dark energy or extra spatial dimension. However, its applications have shown that some subtleties of these theories need a more profound examination. Here we are interested in the conformal aspects of the Palatini approach in extended theories of gravity. As is well known, extremization of the gravitational action a la Palatini, naturally "selects" a new metric h related to the metric g of the subjacent manifold by a conformal transformation. The related conformal function is given by the derivative of f(R). In this work we examine the conformal symmetries of the flat (k=0) FLRW spacetime and find that its Conformal Killing Vectors are directly linked to the new metric h and also that each vector yields a different conformal function.Comment: 3 pages, 1 table, talk given at I CosmoSul: Cosmology and Gravitation in the Southern Con

Test of a universality ansatz for the contact values of the radial distribution functions of hard-sphere mixtures near a hard wall

Recent Monte Carlo simulation results for the contact values of polydisperse hard-sphere mixtures at a hard planar wall are considered in the light of a universality assumption made in approximate theoretical approaches. It is found that the data seem to fulfill the universality ansatz reasonably well, thus opening up the possibility of inferring properties of complicated systems from the study of simpler onesComment: 9 pages, 2 figures; v2: minor changes; to be published in the special issue of Molecular Physics dedicated to the Seventh Liblice Conference on the Statistical Mechanics of Liquids (Lednice, Czech Republic, June 11-16, 2006

Communication: Inferring the equation of state of a metastable hard-sphere fluid from the equation of state of a hard-sphere mixture at high densities

A possible approximate route to obtain the equation of state of the monodisperse hard-sphere system in the metastable fluid region from the knowledge of the equation of state of a hard-sphere mixture at high densities is discussed. The proposal is illustrated by using recent Monte Carlo simulation data for the pressure of a binary mixture. It is further shown to exhibit high internal consistency.Comment: 4 pages, 2 figures; v2: Simulation data for one-component hard spheres included in Fig.

English Language Minority Students and Education Policy: A Focus on the Latinx Population

Our federal government allows states to pass and ratify new laws every year. Over the last thirty years, America has experienced a polarized fight over the expansion or reduction of government involvement. In terms of education policy, local districts and governments can play an essential role in the implementation, evaluation, and development of equitable educational opportunities. This paper examines federal and state level policies in the context of English Language Learners’ (EL) educational opportunities. In particular, I focus on Mt. Diablo High School, which is located in the Mount Diablo District. According to the California State Department of Education, the percentage of English Language Learners at this school is 33.5%. Out of this percentage, a majority of English Language Learner students at Mt. Diablo High School are Latinx (84.98%). These statistics help to demonstrate that state and district level policies lack inclusivity, student awareness on academic resources, accessibility to career center programs, and a lack of parent and teacher participation. Due to these shortcomings, these policies primarily feed into the undereducation and retention of EL students. By analyzing existing Student Site Council meetings and state-level data sets, I argue that there is a higher need for accountability and support relative to the number of EL students attending Mt. Diablo High School

Gender analysis of the changes in indirect taxes introduced by the coalition government, 2010-2011

On behalf of the WBG, Jerome De Henau and Cristina Santos have produced an examination of the UK government's main changes in indirect taxes from a gender perspective. This considers changes in excise duties on alcohol, tobacco, fuel and in VAT, and analyses the combined effect of these changes, together with changes in insurance premium tax, air passenger duty and gambling duty

The morality of political liberalism

The paper discusses two ways to understand political liberalism. On the one hand, political liberalism may rely on the existence of an overlapping consensus among all reasonable comprehensive views present in our society. On the other hand, we may ground political liberalism on the moral value of equal respect for everyone. The dilemma between a factual identification of an overlapping consensus and a normative appeal to moral values arises at two levels. First, when we fill the content of our political conception of justice. And second, when we require impartiality to fill that content. In the former case, we may argue for a particular conception of justice through normative argument with moral premises, or our political conception of justice might be the area where all reasona-ble comprehensive views overlap. Similarly, we require that citizens offer impartial public reasons because this is what people holding different comprehensive views do think ap-propriate, or because they should consider it so. The author argues that we should define our political conception of justice through impartial normative argument, and that we should ground the demand of impartiality on the moral value of equal respect

Contact values of the particle-particle and wall-particle correlation functions in a hard-sphere polydisperse fluid

The contact values $g(\sigma,\sigma')$ of the radial distribution functions of a fluid of (additive) hard spheres with a given size distribution $f(\sigma)$ are considered. A ``universality'' assumption is introduced, according to which, at a given packing fraction $\eta$, $g(\sigma,\sigma')=G(z(\sigma,\sigma'))$, where $G$ is a common function independent of the number of components (either finite or infinite) and $z(\sigma,\sigma')=[2 \sigma \sigma'/(\sigma+\sigma')]\mu_2/\mu_3$ is a dimensionless parameter, $\mu_n$ being the $n$-th moment of the diameter distribution. A cubic form proposal for the $z$-dependence of $G$ is made and known exact consistency conditions for the point particle and equal size limits, as well as between two different routes to compute the pressure of the system in the presence of a hard wall, are used to express $G(z)$ in terms of the radial distribution at contact of the one-component system. For polydisperse systems we compare the contact values of the wall-particle correlation function and the compressibility factor with those obtained from recent Monte Carlo simulations.Comment: 9 pages, 7 figure