Computation of atomic astrophysical opacities

The revision of the standard Los Alamos opacities in the 1980-1990s by a group from the Lawrence Livermore National Laboratory (OPAL) and the Opacity Project (OP) consortium was an early example of collaborative big-data science, leading to reliable data deliverables (atomic databases, monochromatic opacities, mean opacities, and radiative accelerations) widely used since then to solve a variety of important astrophysical problems. Nowadays the precision of the OPAL and OP opacities, and even of new tables (OPLIB) by Los Alamos, is a recurrent topic in a hot debate involving stringent comparisons between theory, laboratory experiments, and solar and stellar observations in sophisticated research fields: the standard solar model (SSM), helio and asteroseismology, non-LTE 3D hydrodynamic photospheric modeling, nuclear reaction rates, solar neutrino observations, computational atomic physics, and plasma experiments. In this context, an unexpected downward revision of the solar photospheric metal abundances in 2005 spoiled a very precise agreement between the helioseismic indicators (the radius of the convection zone boundary, the sound-speed profile, and helium surface abundance) and SSM benchmarks, which could be somehow reestablished with a substantial opacity increase. Recent laboratory measurements of the iron opacity in physical conditions similar to the boundary of the solar convection zone have indeed predicted significant increases (30-400%), although new systematic improvements and comparisons of the computed tables have not yet been able to reproduce them. We give an overview of this controversy, and within the OP approach, discuss some of the theoretical shortcomings that could be impairing a more complete and accurate opacity accountingComment: 31 pages, 10 figures. This review is originally based on a talk given at the 12th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas, Sao Paulo, Brazil, July 2016. It has been published in the Atoms online journa

Renormalization and forcing of horseshoe orbits

In this paper we deal with the Boyland order of horseshoe orbits. We prove that there exists a set $\mathcal{R}$ of renormalizable horseshoe orbits containing only quasi-one-dimensional ones, that is, for these orbits the Boyland order coincides with the unimodal order

Extending cosmology: the metric approach

In this chapter it is shown how the introduction of a fundamental constant of nature with dimensions of acceleration into the theory of gravity makes it possible to extend gravity in a very consistent manner.Comment: 2012, Extending Cosmology: The Metric Approach, Open Questions in Cosmology; Review article for an Intech "Open questions in cosmology" book chapter (19 pages, 3 figures). Available from: http://www.intechopen.com/books/open-questions-in-cosmology/extending-cosmology-the-metric-approac

The Contradiction of Crimmigation

This essay argues that we should find Crimmigration, which is the collapsing of immigration law with criminal law, morally problematic for three reasons. First, it denies those who are facing criminal penalties important constitutional protections. Second, it doubly punishes those who have already served their criminal sentence with an added punishment that should be considered cruel and unusual (i.e., indefinite imprisonment or exile). Third, when the tactics aimed at protecting and serving local communities get usurped by the federal government for immigration enforcement purposes, they often undermine these original aims or get used in ways that conflict with the U.S. Constitution. These concerns should prompt us therefore either to reject the government’s plenary power over immigration or require the federal government to be more consistent about maintaining the separation between criminal law and immigration law

Modeling pre-invasive bronchial epithelial lesions

The growth of cancer cells involves many different processes which can only be captured by a complex model. However, simplified models provide a great deal of insight into the fundamental processes involved. In this workshop we proposed two simple models - one discrete stochastic model and one PDE modelto solve a 2-D simplification of the original problem

[Review of] Flore Zephir, Haitian Immigrants in Black American: A Sociological and Sociolinguistic Portrait

Zephir explores Haitians\u27 identification with Americans through the transitional nature of Haitians\u27 ethnicity, roles of languages, the roles of bilingual educational programs, the generational transmission of Haitian ethnicity, and Haitians\u27 and Black Americans\u27 relationships. For historians and sociologists who are unfamiliar with the history of Haiti and Haitians in American, this book is informative and insightful, especially because of its useful maps and tables. Scholars interested in migration and adaptation are provided with helpful demographic information on Haitians\u27 immigration and settlement in America. Very relevant is a critical discussion of Haiti\u27s history and the resulting effects in the behavior and attitudes of Haitian immigrants in New York

Planting Seeds of Change: Strategies for Engaging Asian Pacific Americans in Healthy Eating and Active Living Initiatives

This 23-page report draws on results from an innovative technique called Photovoice involving 28 community members, community-level data of 308 surveys, as well as extensive input from key stakeholders. Planting Seeds of Change highlights the complexity of engaging Asian Pacific Americans (APAs) in healthy eating and active living efforts. It discusses the opportunities and challenges of a community who has a long agrarian history and ties to the food system. It also discusses issues that come with living as an immigrant and resident in a large metropolitan area. The development of community gardens for Asian Pacific Americans was prioritized as a strategy for addressing access to healthy food, physical activity, and public open spaces.Policy recommendations call for increasing initiatives, funding, and trainings that (1) support and integrate cultural competency into community gardens' outreach, planning, and growing, (2) utilize stewardship programs to increase creation of community gardens, and (3) promote community gardens as a model for leadership development programs. Practice recommendations call for incorporating best practices that community gardens can use to increase participation of APAs in healthy food and active living initiatives, such as site assessments, intensive planning sessions with community, workshops on traditional methods and local sustainability, multi-sectoral collaboration, and creation of sustainability plans

Modeling Particle Transport Distances as a Function of Slope and Surface Roughness

Significant effort has been put into modeling the evolution of hillslope profiles through time. The models use a continuum approach and are commonly deterministic. Early models assumed a linear relationship between hillslope angle and sediment flux. This relationship produces hillslope profiles that increase in steepness from crest to base. However, hillslopes observed in the field are commonly planar downslope of their convex crests. Recently, non-linear sediment transport equations have been developed that produce hillslope profiles closer to those which are observed in nature, yet the mid-slope sections are not entirely planar. Currently, there is interest in using a non-deterministic approach where transport distances follow probability distributions that depend on hillslope angle. In order to qualitatively and quantitatively characterize this probabilistic relationship, the transport distances of individual particles released into a dry ravel flume with a rough surface were measured as a function of flume angle. Using the inputs of flume angle and surface roughness, the results of the experiments were replicated with a discrete element model in which the motion of the particles was modeled with the momentum equation. The implication of this study is that this method can be used with inputs measured from the field to model the evolution of entire hillslopes