663 research outputs found

    Growth and magnetism of self-organized arrays of Fe(110) wires formed by deposition on kinetically grooved W(110)

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    Homoepitaxy of W(110) and Mo(110) is performed in a kinetically-limited regime to yield a nanotemplate in the form of a uniaxial array of hills and grooves aligned along the [001] direction. The topography and organization of the grooves were studied with RHEED and STM. The nanofacets, of type {210}, are tilted 18° away from (110). The lateral period could be varied from 4 to 12nm by tuning the deposition temperature. Magnetic nanowires were formed in the grooves by deposition of Fe at 150°C on such templates. Fe/W wires display an easy axis along [001] and a mean blocking temperature Tb=100KComment: Proceedings of ECOSS 2006 (Paris

    Manipulating Semicrystalline Polymers in Confinement

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    Because final properties of nanoscale polymeric structures are largely determined by the solid-state microstructure of the confined polymer, it is imperative not only to understand how the microstructure of polymers develops under nanoscale confinement but also to establish means to manipulate it. Here we present a series of processing strategies, adapted from methods used in bulk polymer processing, that allow to control the solidification of polymer nanostructures. Firstly, we show that supramolecular nucleating agents can be readily used to modify the crystallization kinetics of confined poly(vinylidene fluoride) (PVDF). In addition, we demonstrate that microstructural features that are not traditionally affected by nucleating agents, such as the orientation of crystals, can be tuned with the crystallization temperature applied. Interestingly, we also show that high crystallization temperatures and long annealing periods induce the formation of the modification of PVDF, hence enabling the simple production of ferro/piezoelectric nanostructures. We anticipate that the approaches presented here can open up a plethora of new possibilities for the processing of polymer-based nanostructures with tailored properties and functionalities

    The dynamical response to the node defect in thermally activated remagnetization of magnetic dot array

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    The influence of nonmagnetic central node defect on dynamical properties of regular square-shaped 5 x 5 segment of magnetic dot array under the thermal activation is investigated via computer simulations. Using stochastic Landau-Lifshitz-Gilbert equation we simulate hysteresis and relaxation processes. The remarkable quantitative and qualitative differences between magnetic dot arrays with nonmagnetic central node defect and magnetic dot arrays without defects have been found.Comment: 4 pages,5 figures, submitted to J. Magn. Magn. Matte

    A Prostaglandin D2 system in the human testis

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    As shown recently, cyclooxygenase 2 (COX2), the inducible key enzyme for the prostaglandin (PG) biosynthetic pathway, is abundantly present in interstitial cells of testes of men suffering from different forms of impaired spermatogenesis and sub- or infertility, but it is absent in human testes with normal spermatogenesis. Although the spectrum of the downstream products of COX2 action in testis, namely PGs, and their effects are not known, our results show that Prostaglandin D2 (PGD2) likely plays a role. We describe (a) PGD2 synthetases, as well as receptors for PGD2 (DP) in testicular interstitial cells of men suffering from spermatogenic damage and infertility, and report that (b) PGD2 is produced by and can affect Leydig cells of an animal model, which expresses testicular COX2 and DP.Fil: Schell, Cristoph. Ludwig Maximilians Universitat; AlemaniaFil: Frungieri, Monica Beatriz. Ludwig Maximilians Universitat; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Albrecht, Martín. Ludwig Maximilians Universitat; AlemaniaFil: Gonzalez de Calvar, Silvia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Köhn, Frank M.. Andrologicum Munich; AlemaniaFil: Calandra, Ricardo Saul. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Mayerhofer, Artur. Ludwig Maximilians Universitat; Alemani

    A Survey of HC3N in Extragalactic Sources - Is HC3N a Tracer of Activity in ULIRGs?

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    Context. HC3N is a molecule that is mainly associated with Galactic star-forming regions, but it has also been detected in extragalactic environments. Aims. To present the first extragalactic survey of HC3N, when combining earlier data from the literature with six new single-dish detections, and to compare HC3N with other molecular tracers (HCN, HNC), as well as other properties (silicate absorption strength, IR flux density ratios, C II flux, and megamaser activity). Methods. We present mm IRAM 30 m, OSO 20 m, and SEST observations of HC3N rotational lines (mainly the J = 10-9 transition) and of the J = 1-0 transitions of HCN and HNC. Our combined HC3N data account for 13 galaxies (excluding the upper limits reported for the non-detections), while we have HCN and HNC data for more than 20 galaxies. Results. A preliminary definition "HC3N-luminous galaxy" is made based upon the HC3N/HCN ratio. Most (~80 %) HC3N-luminous galaxies seem to be deeply obscured galaxies and (U)LIRGs. A majority (~60 % or more) of the HC3N-luminous galaxies in the sample present OH mega- or strong kilomaser activity. A possible explanation is that both HC3N and OH megamasers need warm dust for their excitation. Alternatively, the dust that excites the OH megamaser offers protection against UV destruction of HC3N. A high silicate absorption strength is also found in several of the HC3N-luminous objects, which may help the HC3N to survive. Finally, we find that a high HC3N/HCN ratio is related to a high dust temperature and a low C II flux.Comment: 17 pages, 12 figures, to be published in Astronomy & Astrophysic

    Política, Gobierno e Instituciones en la Provincia de Misiones. El radicalismo como partido gobernante y sus relaciones con la oposición (1983-1987). 16H247

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    Actividades desarrolladas durante el período: Albrecht, Grabriela cursó y aprobó seminarios de la Maestría en Políticas Sociales; avance en la búsqueda de información respecto de las políticas sanitarias en el territorio de Misiones durante el período 1882 – 1953, para presentar el informe final de investigación; Medina, Martín: Defensa de la Tesis de Maestría en Ciencias Políticas; Gómez, Bárbara Natalia: En proceso de redacción de la tesis de maestría; Pyke, Jorge Nelson - Alvarez, Norma Graciela: Entre las actividades desarrolladas durante el 2009, debemos señalar la sistematización de la base de datos en relación con los debates parlamentarios de los diversos proyectos de leyes presentados por los legisladores y el Poder Ejecutivo durante el período 1983-1987. Asimismo se elaboraron ponencias para ser presentadas en diferentes encuentros científicos relaccionados con la temática investigada (ver apartado 9 Producción del Proyecto). Se continuó con el análisis y sistematización de los datos provenientes principalmente de los Diarios de Sesiones en relación con las discusiones de las leyes que, para nuestra investigación, consideramos fundamentales dentro la gestión de gobierno de la UCR

    Política de partidos: conformación y fragmentación de facciones en la provincia de Misiones (1983-2005). Segunda etapa. 16H178

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    El proyecto constituía la continuación de la investigación (Política de Partidos….primera etapa) que se desarrolló durante los años 2003-2004. En esta segunda etapa se profundizaba en el análisis de los partidos políticos –PJ y UCR- de Misiones a partir del año 1983 hasta el 2005. El estudio se centró particularmente en analizar los conflictos (relaciones de poder) subyacentes al interior de los mismo. Investigar y analizar las estrategias implementadas por los actores políticos y las líneas internas con el fin de preservar o acceder al poder partido y, disputar los lugares en las listas de candidatos a cargos electivos

    Rotational Velocities of Individual Components in Very Low Mass Binaries

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    We present rotational velocities for individual components of 11 very low mass (VLM) binaries with spectral types between M7 and L7.5. These results are based on observations taken with the near-infrared spectrograph, NIRSPEC, and the Keck II laser guide star adaptive optics system. We find that the observed sources tend to be rapid rotators (v sin i > 10 km s^(–1)), consistent with previous seeing-limited measurements of VLM objects. The two sources with the largest v sin i, LP 349–25B and HD 130948C, are rotating at ~30% of their break-up speed, and are among the most rapidly rotating VLM objects known. Furthermore, five binary systems, all with orbital semimajor axes ≾3.5 AU, have component v sin i values that differ by greater than 3σ. To bring the binary components with discrepant rotational velocities into agreement would require the rotational axes to be inclined with respect to each other, and that at least one component is inclined with respect to the orbital plane. Alternatively, each component could be rotating at a different rate, even though they have similar spectral types. Both differing rotational velocities and inclinations have implications for binary star formation and evolution. We also investigate possible dynamical evolution in the triple system HD 130948A–BC. The close binary brown dwarfs B and C have significantly different v sin i values. We demonstrate that components B and C could have been torqued into misalignment by the primary star, A, via orbital precession. Such a scenario can also be applied to another triple system in our sample, GJ 569A–Bab. Interactions such as these may play an important role in the dynamical evolution of VLM binaries. Finally, we note that two of the binaries with large differences in component v sin i, LP 349–25AB and 2MASS 0746+20AB, are also known radio sources

    The Submillimeter Array 1.3 mm line survey of Arp 220

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    We present the first aperture synthesis unbiased spectral line survey toward an extragalactic object. The survey covered the 40 GHz frequency range between 202 and 242 GHz of the 1.3 mm atmospheric window. We find that 80% of the observed band shows molecular emission, with 73 features identified from 15 molecular species and 6 isotopologues. The 13C isotopic substitutions of HC3N and transitions from H2(18)O, 29SiO, and CH2CO are detected for the first time outside the Galaxy. Within the broad observed band, we estimate that 28% of the total measured flux is due to the molecular line contribution, with CO only contributing 9% to the overall flux. We present maps of the CO emission at a resolution of 2.9"x1.9" which, though not enough to resolve the two nuclei, recover all the single-dish flux. The 40 GHz spectral scan has been modelled assuming LTE conditions and abundances are derived for all identified species. The chemical composition of Arp 220 shows no clear evidence of an AGN impact on the molecular emission but seems indicative of a purely starburst-heated ISM. The overabundance of H2S and the low isotopic ratios observed suggest a chemically enriched environment by consecutive bursts of star formation, with an ongoing burst at an early evolutionary stage. The large abundance of water (~10^-5), derived from the isotopologue H2(18)O, as well as the vibrationally excited emission from HC3N and CH3CN are claimed to be evidence of massive star forming regions within Arp 220. Moreover, the observations put strong constraints on the compactness of the starburst event in Arp 220. We estimate that such emission would require ~2-8x10^6 hot cores, similar to those found in the Sgr B2 region in the Galactic center, concentrated within the central 700 pc of Arp 220.Comment: Accepted for publication in A&

    Daily feeding and protein metabolism rhythms in Senegalese sole post-larvae

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    Fish hatcheries must adapt larval feeding protocols to feeding behavior and metabolism patterns to obtain more efficient feed utilization. Fish larvae exhibit daily ingesting rhythms rather than ingesting food continuously throughout the day. The aim of this study was to determine the daily patterns of feed intake, protein digestibility, protein retention and catabolism in Senegalese sole post-larvae (Solea senegalensis; 33 days post-hatching) using C-14-labeled Artemia protein and incubation in metabolic chambers. Sole post-larvae were fed at 09: 00, 15: 00, 21: 00, 03: 00 and 09: 00+1 day; and those fed at 09: 00, 21: 00, 03: 00 and 09: 00+1 day showed significantly higher feed intake than post-larvae fed at 15: 00 h (P=0.000). Digestibility and evacuation rate of ingested protein did not change during the whole cycle (P=0.114); however, post-larvae fed at 21: 00 and 03: 00 h showed the significantly highest protein retention efficiency and lowest catabolism (P=0.002). Therefore, results confirm the existence of daily rhythmicity in feeding activity and in the utilization of the ingested nutrients in Senegalese sole post-larvae.Fundacao para a Ciencia e a Tecnologia (FCT; Portugal) [CCMAR/Multi/04326/2013, 310305/FEP/71, IF/00482/2014/CP1217/CT0005]; PROMAR Program; Fundo Regional para a Ciencia e Tecnologia (FEDER); Ministerio de Economia y Competitividad (MINECO; Spain) by project EFISHDIGEST [AGL2014-52888-R]; FEDER/European Region Development Fund (ERDF); Ministerio de Economia y Competitividad (Spain) [BES-2012-051956]; European Social Fund under the Operational Programme for the Enhancement of Human Potentialinfo:eu-repo/semantics/publishedVersio
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