709 research outputs found

    Influence of light intensity on plasma melatonin and locomotor activity rhythms in tench

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    ©2005. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted version of a Published Work that appeared in final form in Chronobiology International: The Journal of Biological and Medical Rhythm Research.Melatonin production by the pineal organ is influenced by light intensity, as has been described in most vertebrate species, in which melatonin is considered a synchronizer of circadian rhythms. In the case of tench, strict nocturnal activity rhythms have been described although the role of melatonin has not been clarified. In this study we investigated daily activity and melatonin rhythms under 12:12 light-dark (LD) conditions with two different light intensities (58.6 and 1091µW/cm2 ), and the effect of one hour broad spectrum white light pulses of different intensities (3.3, 5.3, 10.5, 1091.4 µW/cm2 ) applied at mid darkness (MD) on nocturnal circulating melatonin. The results showed that plasma melatonin in tench under LD 12:12 and high light conditions displayed a rhythmic variation, where values at MD (255.8 ± 65.9 pg/ml) were higher than at mid light (ML) (70.7 ± 31.9 pg/ml). Such a difference between MD and ML values was reduced in animals exposed to LD 12:12 and low light intensity. The application of one hour light pulses at MD lowered plasma melatonin to 111.6 ± 3.2 pg/ml (in the 3.3-10.5 µW/cm2 range) and to 61.8 ± 18.3 pg/ml (with the 1091.4 µW/cm2 light pulse) and totally suppressed nocturnal locomotor activity. These results showed that melatonin rhythms persisted in tench exposed to low light intensity although the amplitude of the rhythm is affected. In addition, it was observed that light pulses applied at MD affected plasma melatonin content and locomotor activity. Such a low threshold suggests that the melatonin system is capable of transducing light even under dim conditions, which may be used by this nocturnal fish to synchronize to weak night light signals (e.g. moonlight cycles

    Feeding entrainment of locomotor activity rhythms, digestive enzymes and neuroendocrine factors in goldfish

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    ©2007. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted version of a Published Work that appeared in final form in Journal of PHYSIOL BEHAV. To access the final edited and published work see http://doi: 10.1016/j.physbeh.2006.10.017L.M. VERA, N. DE PEDRO, E. GÓMEZ-MILÁN, M.J. DELGADO, M.J. SÁNCHEZ MUROS, J.A. MADRID, F.J. SÁNCHEZ-VÁZQUEZ. Feeding entrainment of locomotor activity, digestive enzymes and neuroendocrine factors in goldfish. PHYSIOL BEHAV 90 (2-3) 518-524, 2007. The existence of food anticipatory activity (FAA) in animals subjected to daily feeding schedules seems to be mediated by a feeding-entrainable oscillator (FEO). Such an FEO may help in anticipating meal time and so optimizing food acquisition and nutrient utilization. In this study we investigated the existence of FAA and whether digestive enzymes, plasma cortisol, hypothalamic NPY and gastrointestinal tract (GIT) and plasma melatonin were entrained by periodic feeding in goldfish. We observed that periodically fed goldfish showed FAA in locomotor activity as well as in amylase and NPY. Alkaline protease and GIT melatonin were higher after feeding, whereas plasma cortisol levels were reduced. Plasma melatonin remained unmodified before and after meal time. These results suggested that scheduled feeding entrained both behavioral and certain physiological patterns in goldfish, FAA being of adaptive value to anticipate a meal and prepare the digestive physiology of fish

    Revisión de la obra de Antonio Bisquert en la ciudad de Teruel a través de su análisis radiográfico y caracterización de materiales mediante SEM/EDX

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    El presente trabajo de investigación, con un claro carácter interdisciplinar, se focaliza en un estudio donde se han combinado datos histórico-artísticos junto a una extensa documentación radiográfica, más un amplio estudio estratigráfico y químico mediante Microscopía óptica y Microscopia electrónica de barrido. Todo ello sobre un conjunto de ocho lienzos de la producción artística del pintor Antonio Bisquert en la ciudad de Teruel. Las obras analizadas en este artículo se encuentran localizadas tanto en el Museo de Arte Sacro de Teruel, como en diferentes iglesias de esa misma localidad. Tanto los resultados obtenidos de las imágenes radiográficas como los que ofrecen las pruebas analíticas conforman un compendio inédito de lo que se refleja en todo el proceso creativo y su génesis, revelando atribuciones contrastadas y el empleo de posteriores retoques considerados como no originales, que fueron ejecutados por una misma mano en una misma época. Todos estos datos generan un gran interés para el reconocimiento y puesta en valor de la obra de este olvidado pintor. The present research work, with an interdisciplinary character, focuses on a study where historical-artistic data were combined with extensive radiographic documentation and extensive stratigraphic and chemical studies using optical microscopy and scanning electron microscopy. All this on a set of eight canvases of the artistic work''s Antonio Bisquert in the city of Teruel. These works are located in the Museum of Sacred Art of Teruel and in different churches of this area. The results show a compendium of radiographic unpublished images, which reflects the entire creative process and the genesis of the works, revealing contrasted attributions and the use of subsequent retouchings considered not original, which were executed by the same hand at the same time. All these data generate a great interest for the recognition and the development of forgotten the artist''s output

    The MEDESS-GIB database: tracking the Atlantic water inflow

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    García Sotillo, Marcos ... et al.-- 9 pages, 5 figures, 2 tablesOn 9 September 2014, an intensive drifter deployment was carried out in the Strait of Gibraltar. In the frame of the MEDESS-4MS Project (EU MED Program), the MEDESS-GIB experiment consisted of the deployment of 35 satellite tracked drifters, mostly of CODE-type, equipped with temperature sensor sampling at a rate of 30 min. Drifters were distributed along and on both sides of the Strait of Gibraltar. The MEDESS-GIB deployment plan was designed as to ensure quasi-synoptic spatial coverage. To this end, four boats covering an area of about 680NM2 in 6 h were coordinated. As far as these authors know, this experiment is the most important exercise in the area in terms of number of drifters released. Collected satellite-tracked data along drifter trajectories have been quality controlled and processed to build the presented MEDESS-GIB database. This paper reports the MEDESS-GIB data set that comprises drifter trajectories, derived surface currents and in situ SST measurements collected along the buoys tracks. This series of data is available through the PANGAEA (Data Publisher for Earth and Environmental Science) repository, with the following doi:10.1594/PANGAEA.853701. Likewise, the MEDESS-GIB data will be incorporated as part of the Copernicus Marine historical products. The MEDESS-GIB data set provides a complete Lagrangian view of the surface inflow of Atlantic waters through the Strait of Gibraltar and thus, very useful data for further studies on the surface circulation patterns in the Alboran Sea, and their links with one of the most energetic Mediterranean Sea flows: the Algerian CurrentThe MEDESS-GIB experiment was performed as part of the MEDESS-4MS Project activities (Project ref. 2S-MED11-01), supported by the European Regional Development Fund in the framework of the MED Programme. D. Conti is currently a PhD fellowship (FPI/1543/2013) granted by the Conselleria d’Educació, Cultura i Universitats from the Government of the Balearic Islands co-financed by the European Social Fund. J. M. Sayol is thankful for the financial support of CSIC and FSE with the JAE-pre PhD scholarship programPeer Reviewe

    Fragmentation of daily rhythms associates with obesity and cardiorespiratory fitness in adolescents: The HELENA study

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    Background & aims: Chronobiology studies periodic changes in living organisms and it has been proposed as a promising approach to investigate obesity. We analyze the association of the characteristics of the rest-activity rhythms with obesity, cardiorespiratory fitness and metabolic risk in adolescents from nine European countries. Methods: 1044 adolescents (12.5-17.5 y) were studied. Circadian health was evaluated by actigraphy with accelerometers (Actigraph GT1M). Characteristics of the daytime activity such as fragmentation (intradaily variability), estimated acrophase, and 10 h mean daytime activity index were obtained. Body composition was assessed using Bioelectrical-Impedance-Analysis, skinfold thickness, air-displacement-plethysmography and Dual-energy-X-ray-Absorptiometry. Cardiorespiratory fitness (VO2max) and metabolic risk were studied. Results: Highly fragmented activity rhythms were associated with obesity and central adiposity (P < 0.05). Obese adolescents had-3 times higher odds of having a high fragmentation of daytime activity compared to normal weight adolescents OR (95% CI) = 2.8 (1.170, 6.443). A highly fragmented rhythm was also related to lower cardiorespiratory fitness and higher metabolic risk (P < 0.05) so those adolescents classified as low fitness showed a significantly higher fragmentation of daytime activity than those included in the high fitness group (P < 0.0001). Other characteristics of the rhythms such as smaller 10 h daytime mean activity index and delayed estimated acrophase were also related to obesity and metabolic risk (P < 0.05). Conclusions: Our results indicate that the daily organization of the rest-activity cycle is more fragmented in obese and less fit adolescents and correlates with higher metabolic risk. This fact reinforces our hypothesis that disturbances in daily rhythms can be considered as sensitive markers of poorer adolescent's health

    Environmental impact of aquaculture on the marine benthos: exclusion - inclusion experiments

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    The present paper studies the impact of aquacultural organic wastes and wild fish on the macroinfauna assemblage and on the biogeochemical properties of marine sediments. Exclusion experiments were carried out on coarse and fine sands. Wild fish might reduce the organic material pool by eating feed, feces and infauna, as well as by facilitating the transport of organic materials to other areas. Granulometry stands out as the most important factor in the response of different sediments. We conclude that wild fish can reduce the impact of organic waste from aquaculture.Se ha examinado el impacto de una descarga de materiales orgánicos procedentes de una instalación de acuicultura y se estudia la influencia de la ictiofauna silvestre sobre el ensamblaje de la macroinfauna y las propiedades biogeoquímicas del sedimento. Se realizaron experimentos de exclusión sobre fondos de arenas gruesas y de arenas finas. La ictiofauna silvestre puede suavizar la acumulación de materia orgánica debajo de las jaulas flotantes consumiendo las heces, el pienso y la infauna, o bien facilitando la resuspensión y transporte de materia orgánica a otras zonas. La granulometría se ha destacado como la característica más importante que explica la diferenciación en la respuesta de los sedimentos. Se puede concluir que la ictiofauna silvestre suaviza los impactos derivados del excedente de materia orgánica de las granjas marinas.Instituto Español de Oceanografí

    Interstellar MHD Turbulence and Star Formation

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    This chapter reviews the nature of turbulence in the Galactic interstellar medium (ISM) and its connections to the star formation (SF) process. The ISM is turbulent, magnetized, self-gravitating, and is subject to heating and cooling processes that control its thermodynamic behavior. The turbulence in the warm and hot ionized components of the ISM appears to be trans- or subsonic, and thus to behave nearly incompressibly. However, the neutral warm and cold components are highly compressible, as a consequence of both thermal instability in the atomic gas and of moderately-to-strongly supersonic motions in the roughly isothermal cold atomic and molecular components. Within this context, we discuss: i) the production and statistical distribution of turbulent density fluctuations in both isothermal and polytropic media; ii) the nature of the clumps produced by thermal instability, noting that, contrary to classical ideas, they in general accrete mass from their environment; iii) the density-magnetic field correlation (or lack thereof) in turbulent density fluctuations, as a consequence of the superposition of the different wave modes in the turbulent flow; iv) the evolution of the mass-to-magnetic flux ratio (MFR) in density fluctuations as they are built up by dynamic compressions; v) the formation of cold, dense clouds aided by thermal instability; vi) the expectation that star-forming molecular clouds are likely to be undergoing global gravitational contraction, rather than being near equilibrium, and vii) the regulation of the star formation rate (SFR) in such gravitationally contracting clouds by stellar feedback which, rather than keeping the clouds from collapsing, evaporates and diperses them while they collapse.Comment: 43 pages. Invited chapter for the book "Magnetic Fields in Diffuse Media", edited by Elisabete de Gouveia dal Pino and Alex Lazarian. Revised as per referee's recommendation

    COSMO: Corrientes Marinas y Seguridad en el Medio Marino

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    Ejercicio internacional de salvamento y lucha contra la contaminación marina "Polex 24-17" organizado por la Dirección General de Marina Mercante y Salvamento Marítimo del 14 al 16 de junio de 2017 en SantanderDisponer en tiempo real de información sobre las corrientes oceánicas es clave para algunos de los servicios encomendados a la Sociedad de Salvamento y Seguridad Marítima y al Cuerpo Nacional de Policía (CNP). Un alto porcentaje de las emergencias de búsqueda de personas y náufragos, y de los incidentes de contaminación gestionados por Salvamento Marítimo, tienen lugar en zonas cercanas a la costa. Asimismo, el 71% de los casos de restos humanos no identificados (CSI) acontecidos en España durante el período 1968-2015 se da en zonas costeras. El proyecto COSMO busca mejorar la eficacia de las operaciones de búsqueda y de predicción de derivas, y mejorar la proporción de identificaciones positivas acelerando la resolución de casos de recuperación de restos humanosProyecto cofinanciado por el Ministerio de Economía Industria y Competitividad y Fondos FEDER de la UE (COSMO-CTM2016-79474-R, UE)Peer Reviewe
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