Sphere rolling on the surface of a cone

We analyse the motion of a sphere that rolls without slipping on a conical surface having its axis in the direction of the constant gravitational field of the Earth. This nonholonomic system admits a solution in terms of quadratures. We exhibit that the only circular of the system orbit is stable and furthermore show that all its solutions can be found using an analogy with central force problems. We also discuss the case of motion with no gravitational field, that is, of motion on a freely falling cone.Comment: 12 pages, 2 figures, to be published in Eur J Phy

Effect of dietary free fatty acid content on growth and hepatic morphology in sole (Solea Senegalensis) juveniles

Utilization in aquaculture of unusual meals with unbalanced lipid content or inadequate previous treatment may result in harmful state for fish. This research studied the effects caused by different dietary free fatty acid (FFA) content on growth performance and hepatic morphology in liver in sole juveniles. Results revealed an inverse relationship between dietary FFA content and ability of fish to grow. Moreover, hepatic morphology analysis indicated an overall healthier status in hepatocytes of fish fed with low dietary FFA content. Dietary fatty acids must be esterified to glycerols seem an absolutely necessary requisite in sole, allowing a proper energy storing and its latter mobilisation to gain biomass.This work was supported by Interreg Project 0251_ECOAQUA_5_E, financed by the EDRF (European Regional Development Fund). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaquaLa utilizaci&oacute;n en la acuicultura de dietas inusuales con contenido lip&iacute;dico desequilibrados o tratamientos previos inadecuados puede resultar nocivo para los peces. Esta investigaci&oacute;n estudi&oacute; los efectos causados por distintas dietas con diferente contenido en &aacute;cidos grasos libres (FFA) en el crecimiento y la morfolog&iacute;a hep&aacute;tica en juveniles de lenguado. Los resultados revelaron una relaci&oacute;n inversa entre el contenido de FFA en la dieta y la capacidad de los peces para crecer. Por otra parte, el an&aacute;lisis de la morfolog&iacute;a hep&aacute;tica indic&oacute; un estado m&aacute;s saludable en los hepatocitos de los peces alimentados con una dieta baja en FFA . La esterificaci&oacute;n con glicerina de &aacute;cidos grasos es un requisito indispensable en lenguados, lo que permite un adecuado almacenamiento de energ&iacute;a y su posterior movilizaci&oacute;n para ganar biomasa.Este trabajo fue apoyado por el proyecto Interreg 0251_ECOAQUA_5_E , financiado por el FEDER (Fondo Europeo de Desarrollo Regional). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.</p

Caracterización química del aceite de girasol oxidado mediante UV y ozono con diferentes grados de oxidación y estudio de su acción antimicrobiana

Oxidation by the action of ozone takes place at high rates and involves the reaction of ozone molecules with fatty acid double bonds followed by the formation of stable oxidation products with biological activity. In the present work, a comparative study on sunflower oil oxidized by ultraviolet (UV) light and ozone was carried out. This study involved the chemical characterization of sunflower oil oxidized by UV irradiation and ozonation, in addition to assessing the germicidal activity of oxidized oils obtained under various conditions. The results indicated that under the conditions studied, the increase in the dose of UV irradiation did not produce significant changes in the level of oxidation of the oil. Ozonation promoted the formation of oxygenated compounds at higher rates, increasing in concentration as the applied dosage of ozone increased. The germicidal activity of the oils behaved similarly, with considerably higher activity found in the ozonized oils.La oxidación por acción del ozono tiene lugar a tasas muy altas e implica la reacción de las moléculas de ozono con los dobles enlaces de los ácidos grasos, seguida de la formación de productos de oxidación estables con actividad biológica. En el presente trabajo se realizó un estudio comparativo del aceite de girasol oxidado por luz UV y por ozono. Este estudio consistió en la caracterización química del aceite de girasol oxidado por irradiación UV y por ozonización. En segundo lugar, se evaluó la influencia en la actividad germicida potencial del producto final obtenido en varias condiciones de ozonización. Los resultados indicaron que, en las condiciones estudiadas, el aumento de la dosis de irradiación UV no produjo cambios significativos en el nivel de oxidación del aceite. La ozonización promovió la formación de compuestos oxigenados en mayor proporción, aumentando su concentración a medida que aumentaba la dosis de ozono aplicada. La actividad germicida de los aceites se comportó de forma similar, encontrándose una actividad considerablemente mayor en los aceites ozonizados

Evolución de los deltas submarinos de los ríos Guadalfeo y Adra en respuesta a las variaciones de los aportes sedimentarios

The Guadalfeo and the Adra submarine deltas off the northern coast of the Alboran Sea have been built up under the direct influence of short and mountainous rivers. The area is subjected to strong climatic seasonality, with sporadic winter torrential floods and high summer aridity. In addition numerous anthropogenic activities have affected these systems, mostly during the last two centuries. In order to decode the influence of climatic variability and anthropogenic impacts on sediment supplies during the recent past, five sediment cores were collected from the Guadalfeo and Adra submarine deltas. Benthic foraminiferal and sedimentological analyses, combined with radiocarbon dating, were performed. The impact of torrential floods alternating with periods of low rainfall or dry periods were recorded in the Adra and Guadalfeo prodeltas. Periods with low abundance of benthic foraminifera and high amounts of coarse-grained sediments, were interpreted as the result of enhanced sediment supply to the shelf triggered by major flood events. On the other hand, periods with high amounts of fine-grained sediments and high abundances of colonizers and opportunistic foraminiferal species indicate the establishment of new environments with distinct ecological constraints. These environments were driven by lower sediment supplies during low rainfall or dry periods. The most recent sedimentation seems to reflect the human interventions in the rivers basins, such as deviation of the main river courses and dams construction, which reduced the sediment input and promoted the deposition of shallow-water submarine deltas.Versión del edito

An approach to the spatial distribution of fishing effort in the Gulf of Cadiz.

The spatial distribution of the fishing effort exerted by the trawl fleet of Isla Cristina port (Huelva, Spain) is simulated by means of an application (FAST) for Geographic Information Systems (ArcView), which can offer results just with limited input data. The simulation were carried out with three input variables: depth, distance from fishing grounds to port and the fishing laws in force in the area. The results obtained from two simulations tested match up the effort distribution detected in the area for both the fleet as a whole and a given segment of the same.Postprin

Los mosquitos del estado de Quintana Roo, México (Diptera: Culicidae).

A study on the distribution of the mosquitoes of Quintana Roo State of México was carried out by collecting immature and adult stages during September and October 2006. The collections were made from different locations in the three physiogeographical provinces of the state: Carso Yucateco, Carso, Lomeríos de Campeche, and Costa Baja de Quintana Roo. A total of 420 larvae, 294 pupae, and 726 adults representing 13 genera and 41 species were collected. Two genera, three subgenera, and 11 species are new to the mosquito fauna of Quintana Roo State. Collection and bionomical data are included for species collected during the study, and a checklist of species newly and previously recorded from the state is provided.Un estudio de la distribución de los mosquitos del estado de Quintana Roo, México fue realizado por medio de colectas de estados inmaduros y adultos durante Septiembre y Octubre del 2006. Las colectas fueron realizadas en diferentes localidades de las tres provincias fisiográficas del estado: Carso Yucateco, Carso, Lomeríos de Campeche y Costa Baja de Quintana Roo. Un total de 420 larvas, 294 pupas y 726 adultos fueron colectados representando 13 géneros y 41 especies. Dos géneros, tres subgéneros y 11 especies son nuevos registros estatales para Quintana Roo

The evolution of the Guadalfeo submarine delta (northern Alboran Sea) during the last ca. 200 years

The Guadalfeo submarine delta is located on the northern Alboran Sea shelf in the western Mediterranean Sea. The sedimentary dynamics of the deltaic system is governed by the discharge of one of the major rivers in this area draining the western sector of the near-coastal Sierra Nevada Mountains. The area is under the influence of a Mediterranean climate, with high spatial and temporal (i.e., inter- and intra-annual) rain variability. Major anthropogenic forcing affected the river system during the 1930’s, with the deviation of the main river channel 2.5 km to the west, to its present position. More recently, the construction of Béznar (1977-1985) and Rules (1993-2003) dams have also contributed to limit the amount of sediments exported to the deltaic system. In order to understand the interaction between river discharges and the evolution of the submarine delta at different timescales, sediment cores were collected off the ancient (core 13) and present-day (cores12 and 15) river courses. A chronological framework was performed and combined with sedimentological and benthic foraminiferal analyses. Radiocarbon dating of plant debris from the base of the cores indicates that the sedimentary record goes back 200 years. In core 13, the variations between coarse and fine fractions along the core and the upward increase of benthic foraminiferal population density, would indicate that deposition possibly occurred until the deviation of the main river course to its present position. In the lower part of core 12, the strong alternation between coarse and fine sediment textures and the variable amounts of benthic foraminiferal species are interpreted as the result of an active fluvial regime. The upper part, with high percentages of fine sediments and high values of population density, could be attributed to the stabilization of the river course in its present-day location. Core 15, located at 11 m water depth, showed the highest content of gravel in the lower part of the core, high contents of silt at two core depths and increased percentages of sand to the top, indicating the strong influence of human interventions in the river basin and consequent changes in the sediment supply to the Guadalfeo submarine delta.info:eu-repo/semantics/publishedVersio

Multi-proxy evidence of rainfall variability recorded in subaqueous deltaic deposits off the Adra River, southeast Iberian Peninsula

The Adra River deltaic system, southeast Iberian Peninsula, shows a steep topography and is subjected to strong climatic seasonality. This system has been affected by alternating wet and dry periods, and it has also undergone numerous anthropogenic activities such as deforestation, mining activities, river channel deviations and dam construction, particularly during the last two centuries. Two sediment cores were retrieved off the Adra River, from the western (MS_V9) and eastern (MS_V4) lobes of the subaqueous deltaic deposit. A multi-proxy study was carried out, including grain size, benthic foraminiferal assemblages, magnetic susceptibility and geochemical element analyses, in order to understand the sedimentary expression of recent climatic cycles and anthropogenic interventions in the river basin. Periods of increased deposition of coarse-grained sediments, low absolute abundance of benthic foraminifera and high elemental ratios indicative of terrigenous contributions, were interpreted as periods of increased sediment supply to the shelf. Four flooding events were recorded in core MS_V9 and three events on core MS_V4, of which two were observed in both cores. They were related to periods with major floods that were documented on the southern Iberian Peninsula around 1770e1810 and 1860 e1870 AD. On the other hand, sediment core intervals exhibiting increasing proportion of fine-grained sediments and higher abundances of foraminiferal species assigned as successful colonizers (Textularia earlandi) and opportunistic species that feed on bacteria or terrestrial organic matter (Bolivina ordinaria, Bulimina elongata, Eggerelloides scaber and Ammonia beccarii or tepida), indicate the establishment of new environments with new ecological constraints. They were related to significant decreases of terrigenous sediment input during low rainfall or dry periods. The increase of opportunistic species feeding on fresh phytodetritus (Nonionella iridea, Nonionella stella, Nonionella sp., Brizalina dilatata, Epistominella vitrea and Bolivinellina pseudopuntata), under more stable environmental conditions, also point to a stronger marine influence on the prodeltaic environments during these periods. The human interventions on the river basin after 1872 AD, with the deviation of the main river channel to the east, led to a drastic reduction of the sediment exported to the western delta lobe. This study showed that the sedimentation on the Adra subaqueous deltaic deposit was mainly controlled by rainfall variability from 1663 to 1872 AD, and afterwards by anthropogenic interventions.En prensa2,247

Geological, geochemical and mineralogical characteristics of REE-bearing Las Mercedes bauxite deposit, Dominican Republic

Bauxite deposits, traditionally the main source of 'aluminum, have been recently targeted for their remarkable contents in rare earth elements (REE). With Sigma REE (lanthanoids + Sc + Y) concentrations systematically higher than similar to 1400 ppm (ay. = 1530 ppm), the Las Mercedes karstic bauxites in the Dominican Republic rank as one of the REE-richest deposits of its style.The bauxitic ore in the Las Mercedes deposit is mostly unlithified and has a homogeneous-massive lithostructure, with only local cross-stratification and graded bedding. The dominant arenaceous and round-grained texture is composed of bauxite particles and subordinate ooids, pisoids and carbonate clasts. Mineralogically, the bauxite ore is composed mostly of gibbsite and lesser amounts of kaolinite, hematite, boehmite, anatase, goethite, chromian spinel and zircon. Identified REE-minerals include cerianite and monazite-Ce, whose composition accounts for the steady enrichment in light-relative to medium-and heavy-REE of the studied bauxites.Considering the paleo-geomorphology of the study area, we propose that bauxites in the Las Mercedes deposit are the product of the erosion and deposition of lithified bauxites located at higher elevations in the Bahoruco ranges. Based on the available data, we suggest a mixed lithological source for the bauxite deposits at the district scale: bedrock carbonates and an igneous source of likely mafic composition. (C) 2017 Elsevier B.V. All rights reserved