First order formulation of unimodular gravity

First order Lagrangians for the Weyl invariant formulation of unimodular gravity are proposed. Several alternatives are examined; in some of them, first and second order are equivalent in a certain gauge onlyThis work has been partially supported by the European Union FP7 ITN INVISIBLES (Marie Curie Actions, PITN- GA-2011- 289442) and (HPRN-CT-200-00148), COST action MP1405 (Quantum Structure of Spacetime), COST action MP1210 (The String Theory Universe) as well as by FPA2012-31880 (MINECO, Spain) and S2009ESP-1473 (CA Madrid). The authors acknowledge the support of the Spanish MINECO Centro de Excelencia Severo Ochoa Programme under grant SEV-2012-024

Acreditación de programas en la Universidad de Puerto Rico: Análisis de las políticas para evidenciar un proceso de cambio exitoso, 2003-2014

A first-rate university should demonstrate the excellence and quality of its programs, including how they meet continuous and complex changes in areas such as technological advances, demographic changes, fiscal policies, and new contents in the academic offerings. In 2003, the University of Puerto Rico initiated a process to establish a culture of external scrutiny and evaluation of its programs to ensure that they could respond to the challenge of working with these complex topics. As part of said process, it required that all the programs with voluntary accreditation should be accredited. The project was a success, and 84 percent of those programs were accredited by the corresponding agencies. Taking as reference the model by John P. Kotter, a research specialist on large-scale transformation and change, this article describes the different stages that the programs went through to ensure accreditation. At the same time, it also confirms that the Kotter model is applicable to higher education. Cómo citar: Freytes-González, C. E., & Figueras-Álvarez, C. (2017). Program accreditation at the University of Puerto Rico: Policy analysis to evidence a successful process of change, 2003-2014. Cuaderno de Investigación en la Educación, 32, 126-173. Recuperado a partir de https://revistas.upr.edu/index.php/educacion/article/view/16511Una universidad de primera debe demostrar la excelencia y calidad de sus programas, incluyendo cómo estos atienden cambios continuos y complejos, entre ellos, los adelantos tecnológicos, los cambios demográficos, políticas fiscales y los nuevos contenidos en la oferta académica. En 2003, la Universidad de Puerto Rico inició un proceso para establecer una cultura de evaluación y escrutinio externo que asegurara que sus programas sean de excelencia y capaces de enfrentar estos desafíos. Para ello, requirió la acreditación de todos los programas de acreditación voluntaria. El proyecto fue muy exitoso, y el 84 porciento de esos programas se acreditaron por las agencias correspondientes. Tomando como referencia el modelo de John P. Kotter, especialista en investigaciones sobre las transformaciones y cambios en ambientes a grandes escalas, este trabajo describe las etapas de los programas para acreditarse. Además, confirma que el modelo de Kotter es también aplicable a la educación superior. How to cite: Freytes-González, C. E., & Figueras-Álvarez, C. (2017). Program accreditation at the University of Puerto Rico: Policy analysis to evidence a successful process of change, 2003-2014. Cuaderno de Investigación en la Educación, 32, 126-173. Retrieved from https://revistas.upr.edu/index.php/educacion/article/view/1651

Agricultural nitrogen impacts on aquatic ecosystems

[ES] El desarrollo de la actividad agrícola intensiva de regadío en la segunda mitad del siglo XX, en España pero también en Europa y a nivel global, ha producido que las aguas superficiales y subterráneas se hayan visto sometidas a diversos tipos de estrés. Uno de los más importantes es su estado cualitativo, en el que la lixiviación del exceso de fertilizantes nitrogenados aplicados a los campos agrícolas es el principal mecanismo responsable de las elevadas concentraciones de nitratos medidas en las aguas subterráneas, superiores al límite máximo permitido y recomendado por la legislación existente. Los elevados tiempos de tránsito que normalmente presentan los sistemas acuíferos y su baja capacidad para atenuar la contaminación hacen que éstos se comporten como un almacén de nitrógeno. La exportación del mismo a través del drenaje superficial por su conexión hídrica con cuerpos de agua superficiales constituye el principal mecanismo de contaminación por nitratos de ríos, lagos, mares y océanos. Esas elevadas concentraciones producen problemas de tipo ambiental, como la progresiva eutrofización de sus aguas, así como riesgos para la salud humana, como la enfermedad del “bebe azul”. Para lograr la recuperación de los sistemas y alcanzar el buen estado ecológico de las masas de agua superficiales y subterráneas, se hace necesario el estudio exhaustivo de su funcionamiento hídrico y del origen, el destino y los procesos de transformación a los que es sometido el nitrógeno.[EN] Groundwater and surface water bodies have been affected to various stress types since the second half of the twentieth century due to the development of intensive agricultural irrigation activities not only in Spain but also in Europe and globally. Leaching of nitrogen from fertilizers applied to agricultural fields affects the qualitative state of groundwater resources, due to the high nitrate concentrations measured in this water bodies, above the maximum allowable limit. Groundwater acts as a long-term sink for nitrate due to the high transit times and low remediation capacity to mitigate pollution. Nitrogen exportation through the discharge to surface water bodies is the main mechanism of nitrate pollution of rivers, lakes, seas and oceans. High nitrate concentrations cause environmental issues such as the progressive water eutrophication and human health risks (>blue baby> disease). To achieve good ecological status of water bodies is necessary the comprehensive study of the conceptual model, taking into account the hydric behavior and the source, fate and its transformation processes of the nitrogen cycle.Peer Reviewe

The Villalcampo Shear Zone (Zamora, Spain), geometry, kinematics and the physical conditions of the strain

[Resumen] En este trabajo se presenta una cartografía detallada de un sistema de cizalla que incluye la zona de cizalla de Villalcampo propiamente dicha y las bandas asociadas. Este sistema tiene carácter regional, afecta a granitos intruidos después de la segunda fase hercínica y a sus encajantes metamórficos en un área de al menos 150 Km2. El estudio geométrico y cinemático de las bandas, la distribución de las rocas de falla, así como el estudio microestructural han permitido interpretar todo el sistema como una cizalla subvenical dextra de carácter dúctil-frágil, que termina hacia el NW en un abanico extensional y que se prolonga hacia el SE en otra amplia área interpretada como un duplex extensional. El valor de la cizalla 'Y es de 1,55 y el desplazamiento mínimo calculado es de 3,7 Km. Todas las bandas de cizalla que incluye el sistema de Villalcampo y las venas o filones asociados pueden relacionarse con un único campo de esfuerzos en el que la trayectoria del esfuerzo principal al, subhorizontal y de dirección aproximadamente N-S sufre una desviación en la zona terminal de la banda en sentido diferente según el labio de que se trate, tal como propone Anderson (1951). Para caracterizar el régimen y los mecanismos de la deformación se ha realizado un análisis microestructural detallado de las rocas de falla y un estudio petrográfico y de la petrofábrica de las milonitas. Se concluye que los yacimientos de oro de Pino están controlados estructuralmente por este sistema de cizalla ya que aparecen en venas extensionales ocupadas por milonitas brechificadas; las condiciones de la deformación de carácter alternativamente dúctil-frágil habrtan permitido la migración de fluidos mineralizadores y el sellado de las fracturas en ciclos repetidos. Se propone como hipótesis que los yacimientos de estaño y wolframio que aparecen en la región de Villaseco-Almaraz de Duero puedan estar controlados también por el duplex extensional de este sistema de cizalla.[Abstract] The present work reports" on a detailed mapping of the Villalcampo shear system, including the Villalcampo shear itself together with related shears and veins. This regional shear system affects granites intruded after the second hercynian deformation phase and their metamorphic host rocks over an area of about 150 Km2. A st~ctural study of the shear bands, encompassing geometric and kinematic criteria and also the distribution of fault rocks, has allowed the authors to interpret the whole of the system as a ductile-fragile subvenical dextral shear spaying to the NW in an extensional fan that is prolonged to the SE over a broad area interpreted as an extensional duplex. The value of the shear strain, 'Y = 1.55, and the minimum displacement, s = 3.700 m, is calculated. The distribution of shear bands and veins is coherent with the notion of a single stress field where the principal stress, o"¡, is subhorizontal and has a N-S trajectory that deviates to the tips of the main shear, as proposed by Anderson (1951). With a view to gaining insight into the shearing regimen and the physical conditions of the deformation, a microestructural exploration of the fault rocks was carried out together with a petrographical and petrofabric study of the mylonites. It is concluded that the Pino ore veins -with Au mineralization- are structurally controlled by this shear system because they are related to the extensional veins infilled by brecchiated mylonites. Additionally, it is proposed that the deformation conditions would have alternated between brittle and ductile; this would have permited the migration and sealing of microfractures by mineralizing fluids during repeated cycles. As an hypothesis, it is proposed that the Sn and W ores situated in -the Villaseco -Almaraz area are possibly related to the extensional duplex

Results for the Atlantic cod, roughhead grenadier, redfish, thorny skate and black dogfish of the Spanish Survey in the NAFO Div. 3L for the period 2003-2018

Since 2003, a stratified random spring bottom trawl survey was conducted by Spain in Division 3L of NAFO Regulatory Area (Flemish Pass). The surveys were carried out by the R/V “Vizconde de Eza” using bottom trawl net type Campelen. Entire series of mean catches, biomass and length distribution for Atlantic cod, roughhead grenadier, redfish, thorny skate and black dogfish are presented for the period 2003-2018

Results for the Atlantic cod, roughhead grenadier, redfish, thorny skate and black dogfish of the Spanish Survey in the NAFO Div. 3L for the period 2003-2019

Since 2003, a stratified random spring bottom trawl survey was conducted by Spain in Division 3L of NAFO Regulatory Area (Flemish Pass). The surveys were carried out by the R/V “Vizconde de Eza” using bottom trawl net type Campelen. Entire series of mean catches, biomass and length distribution for Atlantic cod, roughhead grenadier, redfish, thorny skate and black dogfish are presented for the period 2003-2019

Parallel computation of the reachability graph of petri net models with semantic information

Formal verification plays a crucial role when dealing with correctness of systems. In a previous work, the authors proposed a class of models, the Unary Resource Description Framework Petri Nets (U-RDF-PN), which integrated Petri nets and (RDF-based) semantic information. The work also proposed a model checking approach for the analysis of system behavioural properties that made use of the net reachability graph. Computing such a graph, specially when dealing with high-level structures as RDF graphs, is a very expensive task that must be considered. This paper describes the development of a parallel solution for the computation of the reachability graph of U-RDF-PN models. Besides that, the paper presents some experimental results when the tool was deployed in cluster and cloud frameworks. The results not only show the improvement in the total time required for computing the graph, but also the high scalability of the solution, which make it very useful thanks to the current (and future) availability of cloud infrastructures

Serum sample containing endogenous antibodies interfering with multiple hormone immunoassays. Laboratory strategies to detect interference

Objectives: Endogenous antibodies (EA) may interfere with immunoassays, causing erroneous results for hormone analyses. As (in most cases) this interference arises from the assay format and most immunoassays, even from different manufacturers, are constructed in a similar way, it is possible for a single type of EA to interfere with different immunoassays. Here we describe the case of a patient whose serum sample contains EA that interfere several hormones tests. We also discuss the strategies deployed to detect interference. Subjects and methods: Over a period of four years, a 30-year-old man was subjected to a plethora of laboratory and imaging diagnostic procedures as a consequence of elevated hormone results, mainly of pituitary origin, which did not correlate with the overall clinical picture. Results: Once analytical interference was suspected, the best laboratory approaches to investigate it were sample reanalysis on an alternative platform and sample incubation with antibody blocking tubes. Construction of an in-house ''nonsense'' sandwich assay was also a valuable strategy to confirm interference. In contrast, serial sample dilutions were of no value in our case, while polyethylene glycol (PEG) precipitation gave inconclusive results, probably due to the use of inappropriate PEG concentrations for several of the tests assayed. Conclusions: Clinicians and laboratorians must be aware of the drawbacks of immunometric assays, and alert to the possibility of EA interference when results do not fit the clinical pattern

Fabrication of strong magnetic micron-sized supraparticles with anisotropic magnetic properties for magnetorheology

Dr Tavacoli is acknowledged for useful discussions. This work was supported by MICINN PID2019-104883GB-I00 project (Spain), Junta de Andalucı´a P18-FR-2465 project and European Regional Development Fund (ERDF). J. R. M. acknowledges FPU14/01576 fellowship. E. C.-G. acknowledges financial support by CONACYT (Ref. #232347).We propose three different techniques to synthesize anisotropic magnetic supraparticles for their incorporation in the formulation of magnetorheological fluids with novel potential applications. The techniques include microtransfer molding, electrodeposition and microfluidic flow-focusing devices. Although the yield of these methods is not large, with their use, it is possible to synthesize supraparticles with anisotropy in both their magnetic content and shape. The magnetorheological characteristics (yield stress) of the resulting field-induced structures were computed using finite element method simulations and demonstrated to be strongly dependent on the microstructural anisotropy of the supraparticles. In anisotropic particles, the simulated yield stress is always larger than that of the isotropic ones consisting of magnetically homogeneous spherical particles.MICINN PID2019-104883GB-I00 project (Spain)Junta de Andalucía P18-FR-2465 projectEuropean Regional Development Fund (ERDF)FPU14/01576CONACYT (Ref. #232347