1,964 research outputs found
Locally Inertial Reference Frames in Lorentzian and Riemann-Cartan Spacetimes
In this paper we scrutinize the concept of locally inertial reference frames
(LIRF) in Lorentzian and Riemann-Cartan spacetime structures. We present
rigorous mathematical definitions for those objects, something that needs
preliminary a clear mathematical distinction between the concepts of observers,
reference frames, naturally adapted coordinate functions to a given reference
frame and which properties may characterize an inertial reference frame (if
any) in the Lorentzian and Riemann-Cartan structures. We hope to have clarified
some eventual obscure issues associated to the concept of LIRF appearing in the
literature, in particular the relationship between LIRFs in Lorentzian and
Riemann-Cartan spacetimes and Einstein's most happy though, i.e., the
equivalence principle.Comment: In this version a new reference has been added, some misprints and
typos have been corrected and some few sentences in two remarks and in the
conclusions have been changed for better intelligibilit
John Hemings\u27 Monticello and Poplar Forest
A discussion of John Hemings\u27 creative architectural contributions to Monticello and Poplar Forest, Thomas Jefferson\u27s Virginia Estates. Author argues that Hemings, an enslaved person and a master carpenter, made vital and creative contributions to the building of the two estates which merit legal recognition. Author discusses how legal ideas about moral rights and statutory protections in the Architectural Works Copyright Protection Act could be adapted to cure a historica and representative injustice
Commentary on 'Improving the seasonal cycle and interannual variations of biomass burning aerosol sources' by Generoso et al.
In a recent published paper, Generoso et al. (2003) describe a method for improving the spatial and temporal distribution of pyrogenic aerosol emission inventories. In the course of their analysis, the authors note several significant discrepancies in the seasonality of burning as observed by the Visible and Infrared Scanner (VIRS) and four other biomass burning data sets derived from satellite observations. In this commentary we explain the source of these discrepancies and clarify the origin of the VIRS observations that were used by Generoso et al
A schlieren method for ultra-low angle light scattering measurements
We describe a self calibrating optical technique that allows to perform
absolute measurements of scattering cross sections for the light scattered at
extremely small angles. Very good performances are obtained by using a very
simple optical layout similar to that used for the schlieren method, a
technique traditionally used for mapping local refraction index changes. The
scattered intensity distribution is recovered by a statistical analysis of the
random interference of the light scattered in a half-plane of the scattering
wave vectors and the main transmitted beam. High quality data can be obtained
by proper statistical accumulation of scattered intensity frames, and the
static stray light contributions can be eliminated rigorously. The
potentialities of the method are tested in a scattering experiment from non
equilibrium fluctuations during a free diffusion experiment. Contributions of
light scattered from length scales as long as Lambda=1 mm can be accurately
determined.Comment: 7 pages, 3 figure
Analysis of public policies: implementation for environmental management in Brazil: the contribution of social network theory.
Abstract: The paper discusses the implementation of agro-environmental policies in municipalities through concepts of social networks, and proposes a model to do research in the area. The basic assertion is that development, success, or problems of technical actions of implementation are directly influenced by social relationships among actors involved in the task. The article tries to reach two objectives. The first is the application of social network theory to public policies, which is unusual in the literature. The second, as a result, is to present a tool specifically designed to investigate the validity of assumptions that has been tested in four Brazilian municipalities, showing applicability and an ability to generate data for questions about networks. Resumen: El documento analiza la implementación de las políticas agroambientales de los municipios a partir de los conceptos de redes sociales y propone un modelo para la investigación en el área. La afirmación básica es que el desarrollo, el éxito y los problemas de las acciones técnicas dependen de la aplicación de las relaciones sociales en las redes municipales. El trabajo busca dos objetivos. El primero de ellos es utilizar los conceptos de redes sociales en las políticas públicas, lo que hasta el presente no se ha realizado. El segundo, como resultado de lo anterior, es presentar una herramienta metodológica específicamente diseñada para investigar la validez de los supuestos y la herramienta fue probada en cuatro municipios brasileros, mostrando la aplicabilidad y la capacidad de generar datos para las cuestiones sobre redes. Résumé: Le document traite de la mise en ouvre des politiques agroenvironnementales des municipalités des concepts de réseaux sociaux et propose un modèle pour la recherche dans le domaine. L'affirmation fondamentale est que le développement, le succès et les problèmes de mesures techniques dépendent de l'application des relations sociales dans les réseaux municipaux. Le document vise deux objectifs. La première consiste à utiliser des concepts de réseaux sociaux dans les politiques publiques, qui jusqu'à présent n'a pas été réalisé. Deuxièmement, en raison de ce qui précède, est de présenter un outil méthodologique spécifiquement conçue pour étudier la validité des hypothèses et l'outil a été testé dans quatre villes brésiliennes, montrant l'applicabilité et la capacité à générer des données pour les problèmes des réseaux
As relações sociais como fatores determinantes na rede de implementação de políticas ambientais rurais: investigação a partir de alguns municípios do Estado de São Paulo.
Este artigo analisa o estabelecimento das políticas ambientais rurais dos municípios a partir do paradigma da sociedade em rede e dos conceitos de teorias sociais de redes e propõe um modelo para pesquisas na área. A proposição básica é que o desenvolvimento, o sucesso e os problemas das decisões e ações de implementação são diretamente influenciados pelas relações sociais dos atores envolvidos nas tarefas. A pesquisa caracteriza-se como qualitativa e interpretativa, a partir de documentos e entrevistas. Os dados foram coletados e interpretados utilizando-se as regras de análise de conteúdo. Os sujeitos são atores do governo e da sociedade civil e foram realizadas 15 entrevistas. O trabalho chegou a três resultados. O primeiro foi a sustentação da aplicação de teorias sociais de redes ao campo das políticas ambientais rurais, o que é pouco frequente na literatura. O segundo, como decorrência, foi apresentar um instrumento especialmente desenvolvido para investigar a validade dos pressupostos, o qual foi testado em quatro municípios, tendo mostrado aplicabilidade e capacidade de gerar dados para pesquisas e gestão no tema de políticas ambientais rurais. O terceiro foi indicar um caminho de ações gerenciais para as pessoas envolvidas na execução das políticas públicas, tais como os secretários de Meio Ambiente dos municípios
Effectiveness of bystander naloxone administration and overdose education programs: a meta-analysis
The objective of this review was to assess the effectiveness of bystander naloxone administration and overdose education programs by synthesizing quantitative results reported in the research literature. Studies meeting predefined criteria were identified and reviewed, and their results were synthesized through meta-analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for overdose recoveries for individuals who received naloxone dispensed by non-medical community members, and the standardized mean difference was calculated for test scores of non-medical volunteers who received training in overdose management versus the scores of untrained volunteers. Pooled data from four studies showed that naloxone administration by bystanders was associated with a significantly increased odds of recovery compared with no naloxone administration (OR = 8.58, 95% CI = 3.90 to 13.25). Data from five studies of overdose education indicated that average scores were significantly higher for trained participants than untrained participants for tests on naloxone administration, overdose recognition, and overdose response (standardized mean difference = 1.35, 95% CI = 0.92 to 1.77). Empirical evidence in the research literature suggests that bystander naloxone administration and overdose education programs are associated with increased odds of recovery and with improved knowledge of overdose recognition and management in non-clinical settings
Gravitation and Electromagnetism as Geometrical Objects of a Riemann-Cartan Spacetime Structure
In this paper we first show that any coupled system consisting of a
gravitational plus a free electromagnetic field can be described geometrically
in the sense that both Maxwell equations and Einstein equation having as source
term the energy-momentum of the electromagnetic field can be derived from a
geometrical Lagrangian proportional to the scalar curvature R of a particular
kind of Riemann-Cartan spacetime structure, where those fields are identified
as geometrical objects of the structure. We show moreover that the contorsion
tensor of the particular Riemann-Cartan spacetime structure of our theory
encodes the same information as the one contained in Chern-Simons term that is
proportional to the spin density of the electromagnetic field. Next we show
that by adding to the geometrical Lagrangian a term describing the interaction
of a electromagnetic current with a general electromagnetic plus the
gravitational field and a term describing the matter carrier of the current we
get Maxwell equations with source term and Einstein equation having as source
term the sum of the energy-momentum tensors of the electromagnetic and matter
terms. Finally modeling by dust charged matter the carrier of the
electromagnetic current we get the Lorentz force equation. Moreover, we prove
that our theory is gauge invariant. We also briefly discuss our reasons for the
present enterprise.Comment: In this version some few misprints have been corrected and a remark
has changed place. Paper will appear in Advances in Applied Clifford Algebra
Redesigning Public Speaking: A Case Study in the Use of Instructional Design to Create the Interchange Model
This case study describes the redesign of Public Speaking at a Research I institution. An instructional analysis revealed strengths of and concerns about the existing model--large lecture with small lab sections. Criteria for a new model emerged from that analysis, all of which hinged on an overarching goal: The course should incorporate learning theory and disciplinary theory and should result in student learning, student skill development, and enhanced satisfaction among stakeholders. The Interchange Model, which included some online delivery, was developed to meet identified needs and was fleshed out with course materials and semester plans. The model was piloted and then fully implemented with positive results
- …