Using a Gridded Global Dataset to Characterize Regional Hydroclimate in Central Chile

Central Chile is facing dramatic projections of climate change, with a consensus for declining precipitation, negatively affecting hydropower generation and irrigated agriculture. Rising from sea level to 6000 m within a distance of 200 km, precipitation characterization is difficult because of a lack of long-term observations, especially at higher elevations. For understanding current mean and extreme conditions and recent hydroclimatological change, as well as to provide a baseline for downscaling climate model projections, a temporally and spatially complete dataset of daily meteorology is essential. The authors use a gridded global daily meteorological dataset at 0.25° resolution for the period 1948–2008, adjusted by monthly precipitation observations interpolated to the same grid using a cokriging method with elevation as a covariate. For validation, daily statistics of the adjusted gridded precipitation are compared to station observations. For further validation, a hydrology model is driven with the gridded 0.25° meteorology and streamflow statistics are compared with observed flow. The high elevation precipitation is validated by comparing the simulated snow extent to Moderate Resolution Imaging Spectroradiometer (MODIS) images. Results show that the daily meteorology with the adjusted precipitation can accurately capture the statistical properties of extreme events as well as the sequence of wet and dry events, with hydrological model results displaying reasonable agreement with observed streamflow and snow extent. This demonstrates the successful use of a global gridded data product in a relatively data-sparse region to capture hydroclimatological characteristics and extremes

Buffering plasmons in nanoparticle waveguides at the virtual-localized transition

We study the plasmonic energy transfer from a locally excited nanoparticle (LE-NP) to a linear array of small NPs and we obtain the parametric dependence of the response function. An analytical expression allows us to distinguish the extended resonant states and the localized ones, as well as an elusive regime of virtual states. This last appears when the resonance width collapses and before it becomes a localized state. Contrary to common wisdom, the highest excitation transfer does not occur when the system has a well defined extended resonant state but just at the virtual-localized transition, where the main plasmonic modes have eigenfrequencies at the passband edge. The slow group velocity at this critical frequency enables the excitation buffering and hence favors a strong signal inside the chain. A similar situation should appear in many other physical systems. The extreme sensitivity of this transition to the waveguide and LE-NP parameters provides new tools for plasmonics.Comment: Regular article: 7 pages and 5 figure

Simulación numérica de la resistencia al avance de un catamarán usando OpenFOAM

In the present study, numerical resistance predictions using OpenFOAM were performed considering the Cormorant Evolution Catamaran, which provides travel services in the Galapagos Islands. These predictions were compared with experimental data published by Chávez and Lucín [1] and with systematic series [2].Simulations were made at model scale of 2 [m] in two load conditions, considering demi and twin hull (s=0.56 [m]) configurations. A mesh convergence study was performed with 3 different meshes for V=1.05 [m/s] at Light Condition (T=0.086 [m]). The converged mesh, with 1 million of cells approximately, has the lower standard deviation and a 5% error when compared to its experimental value of 1.79 [N]. The errors between the experimental data and the numerical simulations for demi hull configuration were 43% and 36% for Light and Full conditions, respectively. Besides, for twin hull configuration the errors were around 14% and 32% for Light and Full conditions, respectively.En el presente estudio, predicciones numéricas de resistencia usando OpenFOAM fueron realizadas considerando el Catamarán “Cormorant Evolution”, que ofrece servicios turísticos en las Islas Galápagos. Las predicciones numéricas fueron comparadas con datos experimentales publicados por Chávez y Lucín [1], y con métodos estadísticos [2]. Las simulaciones fueron realizadas con un modelo de 2[m] en dos condiciones de carga, considerando uno y los dos cascos (s=0.56 [m]). Se realizó un estudio de convergencia con tres mallas para V=1.05 [m/s] en condición ligera (T=0.086 [m]). La malla seleccionada contiene alrededor de 1 millón de celdas y presenta un error del 5% frente a una resistencia experimental de 1.79 [N]. El promedio de los errores entre datos experimentales y simulaciones numéricas para un casco son del 43% y 36% para condición ligera y cargada, respectivamente. Por otro lado, los errores para dos cascos son del 14% y 32% para condición ligera y cargada, respectivamente

RR Lyrae stars in the globular cluster Palomar 2

A CCD VI imaging time-series over 11-year is employed to explore the light curves of stars in the field of Palomar 2. We discovered 20 RRab and 1 RRc variables. A revision of Gaia-DR3 data enabled us to identify 10 more variables and confirm the RRab nature of 6 of them and one RGB. The cluster membership is discussed and 18 variables are most likely cluster members. The Fourier light curve decomposition for the 11 best quality light curves of cluster member stars leads to independent estimates of the cluster distance 27.2 +- 1.8 kpc and [Fe/H]ZW=-1.39 +- 0.55. We confirm the cluster as of the Oo I type.Comment: 10 pages, 6 figures, 1 table. Submitted to Revista Mexicana de Astronom\'ia y Astrof\'isic

Primer registro del género y la especie Zefevazia peruana (Boucomont, 1902) (Coleoptera: Bolboceratidae: Bolboceratinae) para Ecuador

The first report of the genus and species Zefevazia peruana (Boucomont, 1902) for Ecuador is presented. The species is previously known only from a few localities in northern Peru, and is now also recorded from Santa Elena, southern Ecuador. This report represents the northernmost record of the genus and species.Se presenta el primer reporte del género y la especie Zefevazia peruana (Boucomont, 1902) para Ecuador. La especie es conocida previamente de unas pocas localidades en el norte de Perú, y ahora también es registrada en Santa Elena, sur de Ecuador. Este reporte representa el registro más al norte del género y la especie

Redox-Active Nanomaterials For Nanomedicine Applications

Nanomedicine utilizes the remarkable properties of nanomaterials for the diagnosis, treatment, and prevention of disease. Many of these nanomaterials have been shown to have robust antioxidative properties, potentially functioning as strong scavengers of reactive oxygen species. Conversely, several nanomaterials have also been shown to promote the generation of reactive oxygen species, which may precipitate the onset of oxidative stress, a state that is thought to contribute to the development of a variety of adverse conditions. As such, the impacts of nanomaterials on biological entities are often associated with and influenced by their specific redox properties. In this review, we overview several classes of nanomaterials that have been or projected to be used across a wide range of biomedical applications, with discussion focusing on their unique redox properties. Nanomaterials examined include iron, cerium, and titanium metal oxide nanoparticles, gold, silver, and selenium nanoparticles, and various nanoscale carbon allotropes such as graphene, carbon nanotubes, fullerenes, and their derivatives/variations. Principal topics of discussion include the chemical mechanisms by which the nanomaterials directly interact with biological entities and the biological cascades that are thus indirectly impacted. Selected case studies highlighting the redox properties of nanomaterials and how they affect biological responses are used to exemplify the biologically-relevant redox mechanisms for each of the described nanomaterials

Propiedad Extranjera y Especialización Productiva en la Industria del Vino en Chile

En este trabajo se analizan los diferentes patrones de especialización productiva seguidos por inversionistas extranjeros en la industria del vino en Chile; en particular, su efecto sobre la estructura de propiedad que la firma escoge para su nuevo negocio vitivinícola. Existe evidencia que viñas organizadas como Joint Venture (JV) tienen mayor participación en los segmentos de vinos exportados con mayor valor unitario, respecto al caso de viñas que son filiales de inversionistas extranjeros. La hipótesis central bajo estudio es que para inversionistas extranjeros con producción más especializada en vinos de mayor valor, acuerdos de ‘propiedad compartida’ o JV pueden ser un mecanismo eficiente para incentivar las inversiones y esfuerzos productivos requeridos por tal tipo de producción. Las razones analizadas se refieren fundamentalmente al diseño de incentivos contractuales eficientes.Inversión Extranjera; Joint Venture; Industria Vitivinícola