1,950 research outputs found

    Separation and fractionation of order and disorder in highly polydisperse systems

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    Microcanonical Monte Carlo simulations of a polydisperse soft-spheres model for liquids and colloids have been performed for very large polydispersity, in the region where a phase-separation is known to occur when the system (or part of it) solidifies. By studying samples of different sizes, from N=256 to N=864, we focus on the nature of the two distinct coexisting phases. Measurements of crystalline order in particles of different size reveal that the solid phase segregates between a crystalline solid with cubic symmetry and a disordered phase. This phenomenon is termed fractionation.Comment: 8 pages, 5 figure

    COVID-19 Lockdown and Disney+ strategy on social networks on its launch during the State of alarm in Spain

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    The launch of Disney+ in Spain in March 2020 coincided with the Covid-19 pandemic and a period of home confinement for many Spaniards. This study examines the advertising and engagement strategy used by Disney+ on Twitter and Instagram, analyzing 2,268 messages. The platform’s social media use is similar to that of its competitors, with Twitter used for user engagement and Instagram used for content promotion. However, the study finds that the platform missed the opportunity to emphasize its unique qualities and appeal to the brand’s values. Despite this, Disney+ generated significant engagement during its launch month, reflecting high levels of user anticipation. Popular original productions such as The Mandalorian and Aladdin, as well as acquired content like The Simpsons, indicate the brand’s focus on a family or broad-spectrum target audience, in contrast to the younger and niche audiences favored by its competitors.La llegada de Disney+ a España en marzo de 2020 estuvo marcada por la pandemia del Covid-19. El periodo de confinamiento domiciliario entre la población española coincidió con la irrupción del nuevo servicio streaming de una de las marcas más conocidas y queridas a nivel mundial. Este estudio analiza la estrategia publicitaria y de engagement empleada por Disney+ en Twitter e Instagram. El análisis de contenido incluye 2.268 mensajes. Se aprecia un uso de las redes sociales similar a marcas competidoras como Netflix con un uso de Twitter para informar y responder a los comentarios de los usuarios; mientras que de Instagram se promueven nuevos contenidos, en especial películas. Se observa que en el intento de destacar sus elementos diferenciales como servicio bajo demanda, se pierde la oportunidad de apelar a los valores propios de la marca del ratón. La plataforma consiguió un mejor engagement durante el mes de lanzamiento, lo que muestra la alta expectativa de los usuarios. Entre las publicaciones más virales se encuentran producciones originales como The Mandalorian o Aladdín, pero también productos adquiridos como Los Simpson, y que apuntan al interés de la marca por un target familiar o de amplio espectro, frente a audiencias más jóvenes y de nicho valoradas por la competencia

    Equilibrium fluid-solid coexistence of hard spheres

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    We present a tethered Monte Carlo simulation of the crystallization of hard spheres. Our method boosts the traditional umbrella sampling to the point of making practical the study of constrained Gibb's free energies depending on several crystalline order-parameters. We obtain high-accuracy estimates of the fluid-crystal coexistence pressure for up to 2916 particles (enough to accommodate fluid-solid interfaces). We are able to extrapolate to infinite volume the coexistence pressure (p_{co}=11.5727(10) k_B T/\sigma^3) and the interfacial free energy (\gamma_{100}=0.636(11) k_B T/\sigma^2).Comment: 6 pages, 4 pdf figures. Version to be published in PRL. Appendices contain Supplemental Materia

    Management of coastal dunes affected by shrub encroachment: are rabbits an ally or an enemy of restoration?

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    In coastal dunes, shrub encroachment disrupts natural disturbance, and reduces habitat heterogeneity and species composition. In this paper, we implemented a pilot scale trial aimed at restoring coastal dunes affected by the encroachment by the shrub Retama monosperma (hereinafter Retama) as well as strengthening the populations of Thymus carnosus (regionally cataloged as ‘Critically Endangered’). A total 3 ha of Retama shrub was clearcut in two sites with different Retama cover (54 and 72%). The effect of rabbits on vegetation recovery was assessed by placing exclosures both in treated and untreated plots in Spring, 2015. Plant composition, species richness and diversity were evaluated two years after treatments (with and without Retama clearing, and with and without rabbit exclusion). Retama clearing alone did not allow the recovery of plant composition typical of gray dunes two-years after treatments, but resulted in a biodiversity loss within the Retama understorey when rabbits were present. However, Retama clearing resulted in a significant vigor improvement of T. carnosus in the site with the highest density of Retama. Rabbit exclusion significantly increased species richness and Shannon-Wiener diversity index, and allowed the recovery of plant composition typical of gray dunes. The results suggest that shrub encroachment caused by Retama has a long-lasting negative impact on dune vegetation and that periodic clearing should be combined with rabbit exclusion at least during early restoration stages of dune vegetation. To recover the population of T. carnosus, Retama should be prevented from reaching high cover and periodic clearing without rabbit exclusion is suggested

    Comparación de técnicas para determinar la proporción de verde y seco en Koeleria permollis Nees.

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    Comparación de técnicas para determinar la proporción de verde y seco en Koeleria permollis Nees

    Role of Klotho and AGE/RAGE-Wnt/β-catenin signalling pathway on the development of cardiac and renal fibrosis in diabetes

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    Fibrosis plays an important role in the pathogenesis of long-term diabetic complications and contributes to the development of cardiac and renal dysfunction. The aim of this experimental study, performed in a long-term rat model, which resembles type 1 diabetes mellitus, was to investigate the role of soluble Klotho (sKlotho), advanced glycation end products (AGEs)/receptor for AGEs (RAGE), fibrotic Wnt/β-catenin pathway, and pro-fibrotic pathways in kidney and heart. Diabetes was induced by streptozotocin. Glycaemia was maintained by insulin administration for 24 weeks. Serum and urine sKlotho, AGEs, soluble RAGE (sRAGE) and biochemical markers were studied. The levels of Klotho, RAGEs, ADAM10, markers of fibrosis (collagen deposition, fibronectin, TGF-β1, and Wnt/β-catenin pathway), hypertrophy of the kidney and/or heart were analysed. At the end of study, diabetic rats showed higher levels of urinary sKlotho, AGEs and sRAGE and lower serum sKlotho compared with controls without differences in the renal Klotho expression. A significant positive correlation was found between urinary sKlotho and AGEs and urinary albumin/creatinine ratio (uACR). Fibrosis and RAGE levels were significantly higher in the heart without differences in the kidney of diabetic rats compared to controls. The results also suggest the increase in sKlotho and sRAGE excretion may be due to polyuria in the diabetic rats

    Gamma Irradiation of Magnetoresistive Sensors for Planetary Exploration

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    A limited number of Anisotropic Magnetoresistive (AMR) commercial-off-the-shelf (COTS) magnetic sensors of the HMC series by Honeywell, with and without integrated front-end electronics, were irradiated with gamma rays up to a total irradiation dose of 200 krad (Si), following the ESCC Basic Specification No. 22900. Due to the magnetic cleanliness required for these tests a special set-up was designed and successfully employed. Several parameters of the sensors were monitored during testing and the results are reported in this paper. The authors conclude that AMR sensors without front-end electronics seem to be robust against radiation doses of up to 200 krad (Si) with a dose rate of 5 krad (Si)/hour and up to a resolution of tens of nT, but sensors with an integrated front-end seem to be more vulnerable to radiation

    Opinión de los alumnos respecto a la asignatura del grado de farmacia “Formulación Magistral”

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    La asignatura Formulación Magistral es una asignatura optativa del Grado de Farmacia de la Universidad de Alcalá de carácter tanto teórico como práctico, se ha implementado en el presente curso académico 2014-15, con la intervención de varios profesores. Con objeto de ver la satisfacción de los alumnos en el diseño y puesta en marcha de esta asignatura así como su utilidad se ha diseñado un cuestionario de carácter anónimo para los alumnos matriculados. Este cuestionario fue cumplimentado por el 100% de los alumnos lo cual muestra un gran compromiso dado su carácter voluntario. El análisis de los resultados obtenidos muestra entre otros la gran utilidad de esta asignatura para su futuro profesional al adquirir no sólo conocimientos teóricos sino habilidades prácticas y competencias profesionales (56%). Además el 69% de los alumnos manifiestan que se han alcanzado los objetivos de la asignatura al proporcionar los conocimientos necesarios en el correcto diseño, elaboración, dispensación y aspectos legales de las formulaciones magistrales tanto a nivel hospitalario como de Oficina de Farmacia. El 42% de los alumnos han encontrado que las prácticas facilitan el autoaprendizaje. Aunque otros resultados sugieren la introducción de algunas mejoras para el próximo curso académico

    Peat-forming plants in the Maastrichtian coals of the Eastern Pyrenees

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    The Lower Maastrichtian of Fumanya and neighbouring localities of the Vallcebre syncline (Eastern Pyrenees, Catalonia) provide the first taphonomic evidence for the hypothesis that cheirolepidiacean conifers were significant precursors of Maastrichtian Pyrenean coal. Most Frenelopsis-rich lignite beds do not bear rootlet marks, suggesting that the original peat was detrital. Sedimentological and taphonomic evidence indicates deposition in the margins of a lagoon after the transport of the cheirolepidiacean remains by flotation. The same parautochtonous assemblage includes complete impressions Sabalites longirhachis leaves and large impressions of logs attributed to the same palm trees. Other parautochthonous or allochthonous plant megaremains include extremely rare cycadalean and monocot leaves and abundant minute angiosperm seeds. Rootlet marks associated with thin lignite beds occur at the top of some charophyte limestones. The charophyte association, dominated by in situ accumulation of Peckichara and Microchara gyrogonites, suggests that these limestones were deposited in shallow, freshwater lakes and that the corresponding peat mires were limnic rather than paralic in nature. The botanical affinity of plant remains associated with these root-bearing lignites is uncertain. Palynological analysis showed abundant bisaccates, with less abundant fern spores and freshwater algal oospores. Locally, the abundant rootlet marks were associated with large brush-like rooting structures attributed to Sabalites longirhachis palms. Our results show that, at the beginning of the Maasrichtian, cheirolepidiacean conifers were still significant peat-producing plants, although, unlike analogous Lower Cretaceous ones, they shared this role with rare angiosperms, such as palms
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