624 research outputs found

    Cancellariidae Gray, 1853 del Plioceno de la provincia de Málaga, España

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    Se ha realizado un estudio sistemático de la familia Cancellariidae Gray, 1853 del Plioceno de la provincia de Málaga con el objeto de catalogar la malacofauna perteneciente a dicha familia y la consecuente revisión de las categorías taxonómicas supraespecíficas. Se citan 12 especies: una perteneciente a la subfamilia Admetulinae Troschel, 1869: Admetula sp., y 11 pertenecientes a la subfamilia Cancellariinae Gray, 1853: Cancellaria (Bivetiella) cancellata (Linné, 1766); Sveltia lyrata (Brocchi, 1814); Sveltia varricosa (Brocchi, 1814); Calcarata calcarata (Brocchi, 1814); Trigonostoma (Trigonostoma) umbilicaris (Brocchi, 1814); Trigonostoma (Trigonostoma) bellardii (De Stefani & Pantanelli, 1880); Trigonostoma (Ventrilia) cassidea (Brocchi, 1814); Tribia tribulus (Brocchi, 1814); Bonellitia serrata (Bronn, 1831); Bonellitia bonellii (Bellardi, 1841) y Brocchinia mitraeformis (Brocchi, 1814). Palabras clave: Cancellariidae, Gastropoda, Mollusca, Plioceno, Málaga, España

    Genetic connectivity between Atlantic bluefin tuna (ABFT) Larvae Spawned in the GOM and MED

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    Highly migratory Atlantic bluefin tuna (ABFT) is managed as two stocks, Western and Eastern. Western ABFT spawn mainly in the Gulf of Mexico (GOM) and Eastern ABFT in the Mediterranean Sea (MED) (1). Understanding connectivity between ABFT populations is important for conservation and management of this valuable fishery resource that has been exploited for centuries. ABFT are highly mixed, with multiple disciplines supporting weak structuring between Western and Eastern stocks (1). Concerning genetics, subtle structuring of ABFT populations across the Atlantic Ocean has been the conclusion of studies describing genetic tools for traceability (2,3). Larval fish provide the genetic signal of successful breeders and have occasionally been genetically characterized with juveniles (young-of-the-year, YOY) collected in nursery areas. For the first time, cooperative field collection of tuna larvae during 2014 in the main spawning area for each stock enabled us to assess the structuring of ABFT genetic diversity in a precise temporal and spatial frame exclusively through larvae (5). Partitioning of genetic diversity at nuclear microsatellite loci and in the mitochondrial control region resulted in low significant fixation indices. Individual-based clustering analysis of larval ABFT genetic diversity indicate apparent connectivity between the GOM and MED spawning grounds that could support the hypothesis of mixing of breeders belonging to different stocks.This collaborative study was supported by "ECOLATUN" PROJECT CTM2015-68473-R (MINECO/FEDER) funded by Spanish Ministry of Economy and Competitiveness; "TUNAGEN" project funded by IEO; and "BLUEFIN" project financed by IEO and Balearic Island Observing and Forecasting System (SOCIB). This research was funded by NASA (NNX11AP76G S07), the NOAA National Marine Fisheries Science Service through the Southeast Fisheries Science Center, as well as by Cooperative Institute for Marine and Atmospheric Studies under Cooperative Agreement NA15OAR43200064 at the University of Miami. There was no additional external funding received for this study. The scientific results and conclusions, as well as any views or opinions expressed herein, are those of the author(s) and do not necessarily reflect those of NOAA or the Department of Commerce

    Genetic connectivity between Atlantic bluefin tuna larvae spawned in the Gulf of Mexico and in the Mediterranean Sea

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    The highly migratory Atlantic bluefin tuna (ABFT) is currently managed as two distinct stocks, in accordance with natal homing behavior and population structuring despite the absence of barriers to gene flow. Larval fish are valuable biological material for tuna molecular ecology. However, they have hardly been used to decipher the ABFT population structure, although providing the genetic signal from successful breeders. For the first time, cooperative field collection of tuna larvae during 2014 in the main spawning area for each stock, the Gulf of Mexico (GOM) and the Mediterranean Sea (MED), enabled us to assess the ABFT genetic structure in a precise temporal and spatial frame exclusively through larvae. Partitioning of genetic diversity at nuclear microsatellite loci and in the mitochondrial control region in larvae spawned contemporarily resulted in low significant fixation indices supporting connectivity between spawners in the main reproduction area for each population. No structuring was detected within the GOM after segregating nuclear diversity in larvae spawned in two hydrographically distinct regions, the eastern GOM (eGOM) and the western GOM (wGOM), with the larvae from eGOM being more similar to those collected in the MED than the larvae from wGOM. We performed clustering of genetically characterized ABFT larvae through Bayesian analysis and by Discriminant Analysis of Principal Components (DAPC) supporting the existence of favorable areas for mixing of ABFT spawners from Western and Eastern stocks, leading to gene flow and apparent connectivity between weakly structured populations. Our findings suggest that the eastern GOM is more prone for the mixing of breeders from the two ABFT populations. Conservation of this valuable resource exploited for centuries calls for intensification of tuna ichthyoplankton research and standardization of genetic tools for monitoring population dynamics.This collaborative study was supported by “ECOLATUN” PROJECT CTM2015-68473-R (MINECO/FEDER) funded by Spanish Ministry of Economy and Competitiveness; “TUNAGEN” project funded by Instituto Español de Oceanografía (IEO); and “BLUEFIN” project financed by IEO and Balearic Island Observing and Forecasting System (SOCIB). This research was funded by NASA (NNX11AP76G S07), the NOAA National Marine Fisheries Science Service through the Southeast Fisheries Science Center, as well as by the Cooperative Institute for Marine and Atmospheric Studies under Cooperative Agreement NA15OAR43200064 at the University of Miami, Miami, FL, USA. There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.En prens

    Chemical pressure effects on the spectroscopic properties of Nd3+-doped gallium nano-garnets

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    [EN] Nd3+-doped RE3Ga5O12 (RE = Gd, Y, and Lu) nano-crystalline garnets of 40-45 nm in size have been synthesized by a sol-gel method. With the decrease of the RE atom size, the chemical pressure related to the decreasing volumes of the GaO4 tetrahedral, GaO6 octahedral and REO8 dodecahedral units drive the nano-garnets toward a more compacted structure, which is evidenced by the change of the vibrational phonon mode frequencies. The chemical pressure also increases the crystal-field strength felt by the RE3+ ions while decreases the orthorhombic distortion of the REO8 local environment. These effects alter the absorption and emission properties of the Nd3+ ion measured in the near-infrared luminescence range from 0.87 to 1.43 ¿m associated with the 4 F3/2¿4 IJ (J = 9/2, 11/2, 13/2) transitions. The 4 F3/2 luminescence decay curves show non-exponential behavior due to dipole-dipole energy transfer interactions among Nd3+ ions that increases with pressure.Authors are grateful to The Governments of Spain and India for the Indo-Spanish Joint Programme of Bilateral Cooperation in Science and Technology (PRI-PIBIN-2011-1153/DST-INT-Spain-P-38-11). Dr. Venkatramu is grateful to DAE-BRNS, Government of India for the award of DAE Research Award for Young Scientist (No. 2010/20/34/5/BRNS/2223). This work have been partially supported by MINECO under The National Program of Materials (MAT2013-46649-C4-2-P/-3-P/-4-P), The Consolider-Ingenio 2010 Program (MALTA CSD2007-00045), by Fundacion CajaCanarias (ENER-01), and by the EU-FEDER funds. V. Monteseguro wishes to thank MICINN for the FPI grant (BES-2011-044596). Authors also thank Agencia Canaria de Investigacion, Innovacion y Sociedad de la Informacion for the funds given to Universidad de La Laguna, co-financed by The European Social Fund by a percentage of 85%.Monteseguro, V.; Rathaiah, M.; Linganna, K.; Lozano-Gorrin, AD.; Hernandez-Rodriguez, MA.; Martin, IR.; Babu, P.... (2015). Chemical pressure effects on the spectroscopic properties of Nd3+-doped gallium nano-garnets. Optical Materials Express. 5(8):1661-1673. https://doi.org/10.1364/OME.5.001661S1661167358Pollnau, M., Hardman, P. ., Clarkson, W. ., & Hanna, D. . (1998). Upconversion, lifetime quenching, and ground-state bleaching in Nd3+:LiYF4. Optics Communications, 147(1-3), 203-211. doi:10.1016/s0030-4018(97)00524-5Brandle, C. D., & Barns, R. L. (1974). Crystal stoichiometry of Czochralski grown rare-earth gallium garnets. Journal of Crystal Growth, 26(1), 169-170. doi:10.1016/0022-0248(74)90223-1Venkatramu, V., Giarola, M., Mariotto, G., Enzo, S., Polizzi, S., Jayasankar, C. K., … Speghini, A. (2010). Nanocrystalline lanthanide-doped Lu3Ga5O12garnets: interesting materials for light-emitting devices. Nanotechnology, 21(17), 175703. doi:10.1088/0957-4484/21/17/175703Speghini, A., Piccinelli, F., & Bettinelli, M. (2011). Synthesis, characterization and luminescence spectroscopy of oxide nanopowders activated with trivalent lanthanide ions: The garnet family. Optical Materials, 33(3), 247-257. doi:10.1016/j.optmat.2010.10.039Krsmanović, R., Morozov, V. A., Lebedev, O. I., Polizzi, S., Speghini, A., Bettinelli, M., & Tendeloo, G. V. (2007). Structural and luminescence investigation on gadolinium gallium garnet nanocrystalline powders prepared by solution combustion synthesis. Nanotechnology, 18(32), 325604. doi:10.1088/0957-4484/18/32/325604Naccache, R., Vetrone, F., Speghini, A., Bettinelli, M., & Capobianco, J. A. (2008). Cross-Relaxation and Upconversion Processes in Pr3+ Singly Doped and Pr3+/Yb3+ Codoped Nanocrystalline Gd3Ga5O12: The Sensitizer/Activator Relationship. The Journal of Physical Chemistry C, 112(20), 7750-7756. doi:10.1021/jp711494dAntic-Fidancev, E., Hölsä, J., Lastusaari, M., & Lupei, A. (2001). Dopant-host relationships in rare-earth oxides and garnets doped with trivalent rare-earth ions. Physical Review B, 64(19). doi:10.1103/physrevb.64.195108Rodríguez-Carvajal, J. (1993). Recent advances in magnetic structure determination by neutron powder diffraction. Physica B: Condensed Matter, 192(1-2), 55-69. doi:10.1016/0921-4526(93)90108-iMonteseguro, V., Rodríguez-Hernández, P., Ortiz, H. M., Venkatramu, V., Manjón, F. J., Jayasankar, C. K., … Muñoz, A. (2015). Structural, elastic and vibrational properties of nanocrystalline lutetium gallium garnet under high pressure. Physical Chemistry Chemical Physics, 17(14), 9454-9464. doi:10.1039/c4cp05903dRay, S., León-Luis, S. F., Manjón, F. J., Mollar, M. A., Gomis, Ó., Rodríguez-Mendoza, U. R., … Lavín, V. (2014). Broadband, site selective and time resolved photoluminescence spectroscopic studies of finely size-modulated Y2O3:Eu3+ phosphors synthesized by a complex based precursor solution method. Current Applied Physics, 14(1), 72-81. doi:10.1016/j.cap.2013.07.027Nekvasil, V. (1978). The Crystal Field for Nd3+ in Garnets. Physica Status Solidi (b), 87(1), 317-323. doi:10.1002/pssb.2220870137Rodríguez-Mendoza, U. R., León-Luis, S. F., Muñoz-Santiuste, J. E., Jaque, D., & Lavín, V. (2013). Nd3+-doped Ca3Ga2Ge3O12garnet: A new optical pressure sensor. Journal of Applied Physics, 113(21), 213517. doi:10.1063/1.4809217Kaminska, A., Buczko, R., Paszkowicz, W., Przybylińska, H., Werner-Malento, E., Suchocki, A., … Saxena, S. (2011). Merging of the4F3/2level states of Nd3+ions in the photoluminescence spectra of gadolinium-gallium garnets under high pressure. Physical Review B, 84(7). doi:10.1103/physrevb.84.075483Allik, T. H., Stewart, S. A., Sardar, D. K., Quarles, G. J., Powell, R. C., Morrison, C. A., … Pinto, A. A. (1988). Preparation, structure, and spectroscopic properties ofNd3+:{La1−xLux}3[Lu1−yGay]2Ga3O12crystals. Physical Review B, 37(16), 9129-9139. doi:10.1103/physrevb.37.9129Wu, K., Yao, B., Zhang, H., Yu, H., Wang, Z., Wang, J., & Jiang, M. (2010). Growth and properties of Nd:Lu3Ga5O12 laser crystal by floating-zone method. Journal of Crystal Growth, 312(24), 3631-3636. doi:10.1016/j.jcrysgro.2010.09.029Jia, Z., Arcangeli, A., Tao, X., Zhang, J., Dong, C., Jiang, M., … Tonelli, M. (2009). Efficient Nd3+→Yb3+ energy transfer in Nd3+,Yb3+:Gd3Ga5O12 multicenter garnet crystal. Journal of Applied Physics, 105(8), 083113. doi:10.1063/1.3115442Guillot-Noel, O., Bellamy, B., Viana, B., & Gourier, D. (1999). Correlation between rare-earth oscillator strengths and rare-earth–valence-band interactions in neodymium-dopedYMO4(M=V,P, As),Y3Al5O12,andLiYF4matrices. Physical Review B, 60(3), 1668-1677. doi:10.1103/physrevb.60.1668Demidovich, A. A., Shkadarevich, A. P., Danailov, M. B., Apai, P., Gasmi, T., Gribkovskii, V. P., … Batay, L. E. (1998). Comparison of cw laser performance of Nd:KGW, Nd:YAG, Nd:BEL, and Nd:YVO 4 under laser diode pumping. Applied Physics B: Lasers and Optics, 67(1), 11-15. doi:10.1007/s003400050467Inokuti, M., & Hirayama, F. (1965). Influence of Energy Transfer by the Exchange Mechanism on Donor Luminescence. The Journal of Chemical Physics, 43(6), 1978-1989. doi:10.1063/1.1697063Lupei, V., & Lupei, A. (2000). Emission dynamics of the4F3/2level ofNd3+in YAG at low pump intensities. Physical Review B, 61(12), 8087-8098. doi:10.1103/physrevb.61.8087Maeda, K., Wada, N., Umino, M., Abe, M., Takada, Y., Nakano, N., & Kuroda, H. (1984). Concentration Dependence of Fluorescence Lifetime of Nd3+-Doped Gd3Ga5O12Lasers. Japanese Journal of Applied Physics, 23(Part 2, No. 10), L759-L760. doi:10.1143/jjap.23.l759Geusic, J. E., Marcos, H. M., & Van Uitert, L. G. (1964). LASER OSCILLATIONS IN Nd‐DOPED YTTRIUM ALUMINUM, YTTRIUM GALLIUM AND GADOLINIUM GARNETS. Applied Physics Letters, 4(10), 182-184. doi:10.1063/1.1753928Löhring, J., Nicklaus, K., Kujath, N., & Hoffmann, D. (2007). Diode pumped Nd:YGG laser for direct generation of pulsed 935 nm radiation for water vapour measurements. Solid State Lasers XVI: Technology and Devices. doi:10.1117/12.708220Maunier, C., Doualan, J. L., Moncorgé, R., Speghini, A., Bettinelli, M., & Cavalli, E. (2002). Growth, spectroscopic characterization, and laser performance of Nd:LuVO_4, a new infrared laser material that is suitable for diode pumping. Journal of the Optical Society of America B, 19(8), 1794. doi:10.1364/josab.19.00179

    Reversible temperature-driven domain transition in bistable Fe magnetic nanostrips grown on Ru(0001)

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    © 2015 American Physical Society. High-aspect-ratio Fe nanostrips are studied with real-space micromagnetic imaging methods. We experimentally demonstrate reversible switching from essentially homogeneous single-domain states at room temperature to multidomain diamond states at elevated temperature. This temperature-dependent magnetic bistability can be understood and modeled by accounting for the temperature dependence of the magnetocrystalline, shape, and magnetoelastic anisotropies. These results show how the transition temperature between two magnetic domain states can be tailored by controlling epitaxial strain and particle geometry, which may generate new opportunities for magnetic memory and logic device design.Peer Reviewe

    Dependence of Induced Biological Damage on the Energy Distribution and Intensity of Clinical Intra-Operative Radiotherapy Electron Beams

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    The survival fraction of epithelial HaCaT cells was analysed to assess the biological damage caused by intraoperative radiotherapy electron beams with varying energy spectra and intensities. These conditions were achieved by irradiating the cells at different depths in water using nominal 6 MeV electron beams while consistently delivering a dose of 5 Gy to the cell layer. Furthermore, a Monte Carlo simulation of the entire irradiation procedure was performed to evaluate the molecular damage in terms of molecular dissociations induced by the radiation. A significant agreement was found between the molecular damage predicted by the simulation and the damage derived from the analysis of the survival fraction. In both cases, a linear relationship was evident, indicating a clear tendency for increased damage as the averaged incident electron energy and intensity decreased for a constant absorbed dose, lowering the dose rate. This trend suggests that the radiation may have a more pronounced impact on surrounding healthy tissues than initially anticipated. However, it is crucial to conduct additional experiments with different target geometries to confirm this tendency and quantify the extent of this effect

    Subwavelength slit acoustic metamaterial barrier

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    [EN] Reduction of noise in the transmission path is a very important environmental problem. The standard method to reduce this noise level is the use of acoustic barriers. In this paper, an acoustic metamaterial based on sound transmission through subwavelength slits, is tailored to be used as an acoustic barrier. This system consists of two rows of periodic repetition of vertical rigid pickets separated by a slit of subwavelength width, embedded in air. Here, both the experimental and the numerical analyses are presented. These analyses have facilitated the identification of the parameters that affect the insertion loss performance. The results demonstrated that the proposed barrier can be tuned to mitigate a band noise in a mechanical plant for buildings where openings for air flow are required as well as industrial noise, without excessive barrier thickness.This work was financially supported by the Spanish Ministry of Science and Innovation through project MAT2010-16879.Rubio Michavila, C.; Candelas Valiente, P.; Belmar Ibáñez, F.; Gómez Lozano, V.; Uris Martínez, A. (2015). Subwavelength slit acoustic metamaterial barrier. Journal of Physics D: Applied Physics. 48(39):1-9. https://doi.org/10.1088/0022-3727/48/39/395501S19483
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