Relativistic Positioning Systems: The Emission Coordinates

This paper introduces some general properties of the gravitational metric and the natural basis of vectors and covectors in 4-dimensional emission coordinates. Emission coordinates are a class of space-time coordinates defined and generated by 4 emitters (satellites) broadcasting their proper time by means of electromagnetic signals. They are a constitutive ingredient of the simplest conceivable relativistic positioning systems. Their study is aimed to develop a theory of these positioning systems, based on the framework and concepts of general relativity, as opposed to introducing `relativistic effects' in a classical framework. In particular, we characterize the causal character of the coordinate vectors, covectors and 2-planes, which are of an unusual type. We obtain the inequality conditions for the contravariant metric to be Lorentzian, and the non-trivial and unexpected identities satisfied by the angles formed by each pair of natural vectors. We also prove that the metric can be naturally split in such a way that there appear 2 parameters (scalar functions) dependent exclusively on the trajectory of the emitters, hence independent of the time broadcast, and 4 parameters, one for each emitter, scaling linearly with the time broadcast by the corresponding satellite, hence independent of the others.Comment: 13 pages, 3 figures. Only format changed for a new submission. Submitted to Class. Quantum Gra

Compliance with the Municipal Agro-Environmental Legislation in Francisco de Orellana, Ecuador

The Decentralized Autonomous Municipal Government of the Francisco de Orellana canton is made up of the following rural parishes: Alejandro Labaka, Armenia, Dayuma, El Dorado, El Edén, García Moreno, Guayusa, Inés Arango, La Belleza, Nuevo Paraiso, Taracoa and the Urban Parish of El Coca. The Constitution of the Republic of Ecuador (2008) establishes the rights of nature and protects the biodiversity of the Amazon ecosystem. This is complemented by the provisions of the Organic Code of Territorial Organization, Autonomy and Decentralization (2010), the Organic Code of the Environment (2017) and also the Organic Law for the Integrated Planning of the Special Amazon Territorial District (2018). This article reviewed compliance with municipal agro-environmental legislation in the Decentralized Municipal Autonomous Government of the Francisco de Orellana canton. This analysis was based on the publication of the Organic Law for the Integrated Planning of the Special Territorial District of the Amazon in the Official Registry Supplement 245, dated May 21, 2018. A qualitative methodology was used. Data were collected through analysis of public policies, regulations, legislation and ordinances, and interviews with the main actors of the Decentralized Municipal Autonomous Government. The results suggested that the Municipal Government seeks to protect the biodiversity of the Amazon ecosystem by adopting sustainable development and conservation policies, but it is clear that ordinances are needed for agro-environmental education, garbage classification, recycling, organic gardens, and greater integration into municipal agro-environmental projects. Keywords: agriculture, Amazon, environment, biodiversity, municipal, Ecuador. Resumen El Gobierno Autónomo Descentralizado Municipal del cantón Francisco de Orellana está integrado por las Parroquias Rurales: Alejandro Labaka, Armenia, Dayuma, El Dorado, El Edén, García Moreno, Guayusa, Inés Arango, La Belleza, Nuevo Paraiso, Taracoa y la Parroquia Urbana de El Coca. La Constitución de la República del Ecuador (2008), establece los derechos de la naturaleza y protege la biodiversidad del ecosistema amazónico, esto se complementa con lo establecido en el Código Orgánico de Organización Territorial Autonomía y Descentralización (2010), el Código Orgánico del Ambiente (2017) y ademas la Ley Orgánica para la Planificación Integral de la Circunscripción Territorial Especial Amazónica (2018). Este artículo revisa el cumplimiento de la legislación agroambiental municipal en el Gobierno Autónomo Descentralizado Municipal del cantón Francisco de Orellana, este análisis se realiza a partir de la publicación de la Ley Orgánica para la Planificación Integral de la Circunscripción Territorial Especial Amazónica en el Registro Oficial Suplemento 245, de fecha 21 de mayo del 2018. La metodología utilizada se basó en un análisis cualitativo usando técnicas y herramientas como la obtención de datos, análisis de las políticas públicas, normativa, legislación, ordenanzas y entrevista con los principales actores del Gobierno Autónomo Descentralizado Municipal del cantón Francisco de Orellana. Los principales resultados sugieren que el Gobierno Municipal busque precautelar la biodiversidad del ecosistema amazónico, adoptando políticas de desarrollo sostenible y de conservación, pero es evidente que son necesarias ordenanzas encaminadas a la educación agroambiental, clasificación de la basura, reciclaje, huertos orgánicos, y una mayor integración en proyectos agroambientales municipales. Palabras clave: agricultura, Amazonía, ambiente, biodiversidad, municipal, Ecuador

Jet shapes in ep collisions at HERA

New measurements of the jet shape in ep collisions at HERA using the k_T-cluster jet algorithm are presented.Comment: 7 pages, 3 figures; plenary talk given at the 3rd UK Phenomenology Workshop on HERA Physics, Durham, UK, September 199

Developing numerical libraries in Java

The rapid and widespread adoption of Java has created a demand for reliable and reusable mathematical software components to support the growing number of compute-intensive applications now under development, particularly in science and engineering. In this paper we address practical issues of the Java language and environment which have an effect on numerical library design and development. Benchmarks which illustrate the current levels of performance of key numerical kernels on a variety of Java platforms are presented. Finally, a strategy for the development of a fundamental numerical toolkit for Java is proposed and its current status is described.Comment: 11 pages. Revised version of paper presented to the 1998 ACM Conference on Java for High Performance Network Computing. To appear in Concurrency: Practice and Experienc

Photodegradation of nimodipine and felodipine in microheterogeneous systems

Indexación: Web of Science; ScieloThe photochemical behavior of nimodipine (NIMO) and felodipine (FELO), photolabile drugs widely used as antihypertensive calcium channel blockers, is studied in constrained media. Specifically, we are interested in the kinetic analysis of 4-aryl-1,4-dihydropyridine photodegradation processes when they are incorporated in biological-mimicking systems like micelles or liposomes. In order to establish if the nature of the head of surfactant (ionic or nonionic) could be important modulating the photo-reactivity of these drugs, we studied the photodegradation of NIMO and FELO incorporated in micelles formed with sodium dodecyl sulfate (SDS, anionic), dodecyl-pyridinium chloride (DPC, cationic) and mono lauryl sucrose ester (MLS, nonionic) as surfactants. Additionally, the results of the photodegradation of these compounds in liposomes were also included. The results clearly indicate that both dihydropyridines studied, NIMO and FELO, are located near to the interface, but the surface charge of micelles does not affect neither, the photodegradation rate constant nor the photodegradation products profile. The absence of singlet oxygen generation in micellar media is consistent with the proposition of these 4-aryl-1,4-dihidropyridines located near to the interface of the micelle, where a polar environment is sensed. In addition, the ethanol preferential location on membranes and dihydropyridine enhanced photodegradation by alcohol presence are interesting results to consider in future research.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000300025&nrm=is