DNA Nucleobase Synthesis at Titan Atmosphere Analog by Soft X-rays

Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of N2 and CH4 and includes traces of many simple organic compounds. This atmosphere also partly consists of haze and aerosol particles which during the last 4.5 gigayears have been processed by electric discharges, ions, and ionizing photons, being slowly deposited over the Titan surface. In this work, we investigate the possible effects produced by soft X-rays (and secondary electrons) on Titan aerosol analogs in an attempt to simulate some prebiotic photochemistry. The experiments have been performed inside a high vacuum chamber coupled to the soft X-ray spectroscopy beamline at the Brazilian Synchrotron Light Source, Campinas, Brazil. In-situ sample analyses were performed by a Fourier transform infrared spectrometer. The infrared spectra have presented several organic molecules, including nitriles and aromatic CN compounds. After the irradiation, the brownish-orange organic residue (tholin) was analyzed ex-situ by gas chromatographic (GC/MS) and nuclear magnetic resonance (1H NMR) techniques, revealing the presence of adenine (C5H5N5), one of the constituents of the DNA molecule. This confirms previous results which showed that the organic chemistry on the Titan surface can be very complex and extremely rich in prebiotic compounds. Molecules like these on the early Earth have found a place to allow life (as we know) to flourish.Comment: To appear in Journal of Physical Chemistry A.; Number of pages: 6; Number of Figures: 5; Number of Tables: 1; Number of references:49; Full paper at http://pubs.acs.org/doi/abs/10.1021/jp902824

Prospects for the Improvement of Energy Performance in Agroindustry Using Phase Change Materials

This work was partially supported by the Fundação para a Ciência e Tecnologia, UIDB/00066/2020 (CTS – Center of Technology and Systems).The use of Phase Change Materials (PCMs), able to store latent heat, represents an opportunity to improve energy efficiency in the agroindustry by means of thermal energy storage. PCMs provide higher energy density then sensible heat storage mediums, thus paving the way to multiple applications, like supporting the integration of renewables or allowing for new storage architectures, decentralized and directly installed in the chain production equipment, creating e.g. the opportunity to recover and value low-grade operational heat sub-products. Such new and decentralized architecture, not currently applied in agroindustry, is proposed in this work. A chocolate tempering machine using an organic PCM is conceived and analyzed using ANSYS Fluent software for computational fluid dynamics simulations, comparing the main aspects in the storage capacity and discharging process with a conventional sensitive heat storage solution that uses water. PCMs allows improving the stored energy, keeping the chocolate in the working temperature after being tempered for more than four times longer than using only hot water. If the PCMs are charged by renewables, the self-consumption ratio can be improved while providing energy flexibility to the user.authorsversionpublishe

Protection of Spanish Ibex (Capra pyrenaica) against Bluetongue Virus Serotypes 1 and 8 in a Subclinical Experimental Infection

Many wild ruminants such as Spanish ibex (Capra pyrenaica) are susceptible to Bluetongue virus (BTV) infection, which causes disease mainly in domestic sheep and cattle. Outbreaks involving either BTV serotypes 1 (BTV-1) and 8 (BTV-8) are currently challenging Europe. Inclusion of wildlife vaccination among BTV control measures should be considered in certain species. In the present study, four out of fifteen seronegative Spanish ibexes were immunized with a single dose of inactivated vaccine against BTV-1, four against BTV-8 and seven ibexes were non vaccinated controls. Seven ibexes (four vaccinated and three controls) were inoculated with each BTV serotype. Antibody and IFN-gamma responses were evaluated until 28 days after inoculation (dpi). The vaccinated ibexes showed significant (P<0.05) neutralizing antibody levels after vaccination compared to non vaccinated ibexes. The non vaccinated ibexes remained seronegative until challenge and showed neutralizing antibodies from 7 dpi. BTV RNA was detected in the blood of non vaccinated ibexes from 2 to the end of the study (28 dpi) and in target tissue samples obtained at necropsy (8 and 28 dpi). BTV-1 was successfully isolated on cell culture from blood and target tissues of non vaccinated ibexes. Clinical signs were unapparent and no gross lesions were found at necropsy. Our results show for the first time that Spanish ibex is susceptible and asymptomatic to BTV infection and also that a single dose of vaccine prevents viraemia against BTV-1 and BTV-8 replication

The stratigraphy of Sierra de Neiba (Dominican Republic)

La reciente cartografía a escala 1:50.000 de los sectores centrales y meridionales, más desconocidos, de la Sierra de Neiba ha permitido establecer con mayor precisión su estratigrafía. Los materiales más antiguos corresponden a la Unidad de El Manguito, del Cretácico Superior. Son calizas y lutitas pizarrosas con intercalaciones de basaltos que afloran como un fragmento o bloque tectónico de interpretación estructural dudosa en el núcleo de un anticlinal. Por su edad, se considera que esta unidad debe constituir el sustrato de las series paleógenas de la Sierra de Neiba; la composición geoquímica de los basaltos (OIB-basaltos alcalinos intraplaca) sugiere su correlación con la meseta oceánica del Caribe. El registro estratigráfico más o menos continuo comienza en el Eoceno Inferior con el desarrollo de una extensa plataforma carbonatada, relativamente uniforme, que fue el medio de depósito de la Fm Neiba (sensu lato) y sus equivalentes, hasta el Mioceno Inferior. Durante buena parte del Eoceno, estos depósitos carbonatados coexistieron o fueron sustituidos por materiales volcánicos de signatura toleítica a alcalina (OIT a OIA) que se agrupan bajo la nueva denominación de Complejo Volcanosedimentario de El Aguacate de Neiba y se interpretan como generados en un contexto de intraplaca asociados al desarrollo de una pluma mantélica. La sedimentación de la Fm Sombrerito durante el Mioceno muestra los primeros signos de inestabilidad en la región: mientras que en los sectores septentrionales y centrales de la sierra sus facies más típicas se depositan en una cuenca turbidítica, en su extremo suroccidental afloran las calizas arrecifales de su Mb Barahona, propias de ambientes de plataforma somera, que se extienden con gran uniformidad hacia el sur hasta los dominios de la Sierra de Bahoruco. La Unidad de Cortadero, de nueva denominación y equivalente en edad a la Fm Sombrerito, con una posición intermedia entre ambos tipos de facies, puede representar el tránsito entre ellas.The recent 1:50.0000 scale mapping of the central and southern, most unknown, parts of the Sierra de Neiba, has allowed to establish its stratigraphy with higher precision. The oldest materials belong to the El Manguito Unit, of Upper Cretaceous age. They are limestones and shales with interbedded basalts that outcrop as part of a fragment or tectonic block of unknown structural origin in the core of an anticline. In view of its age, this unit may be considered to be the substratum of the Sierra de Neiba Palaeogene formations. The geochemical signature of the basalts (OIB-alkaline intraplate basalts) suggests their correlation to the Caribbean oceanic plateau. The continuous stratigraphic record starts in the Lower Eocene with the onset of an extensive relatively uniform carbonate platform that was the depositional environment for the Neiba Fm (sensu lato) and equivalent units up to the Lower Miocene. During most of the Eocene, these carbonate deposits coexisted with, or were replaced by, volcanic materials of a tholeitic to alkaline signature (OIT to OIA) grouped under the new denomination of El Aguacate de Neiba Volcanosedimentary Complex, and interpreted to originate in an intraplate context under the effect of a mantel plume. The sedimentation of the Sombrerito Fm during the Miocene reveals the first signs of regional instability: whereas in the northern and central areas of the sierra its most typical facies were deposited in a turbiditic basin, in its southwest margin the coral reef limestones of the Barahona Mb represent shallow platform environments that extended farther south to the domains of Sierra de Bahoruco. It is suggested that the Cortadero Unit, with the same age as the Sombrerito Fm and an intermediate position between these two extreme kind of facies, may represent the transition from one to the other.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUERepública Dominicana. Dirección General de MineríaUnidad Técnica de Gestión del programa SYSMINpu

Floating Patches of HCN at the Surface of Their Aqueous Solutions - Can They Make "HCN World" Plausible?

The liquid/vapor interface of the aqueous solutions of HCN of different concentrations has been investigated using molecular dynamics simulation and intrinsic surface analysis. Although HCN is fully miscible with water, strong interfacial adsorption of HCN is observed at the surface of its aqueous solutions, and, at the liquid surface, the HCN molecules tend to be located even at the outer edge of the surface layer. It turns out that in dilute systems the HCN concentration can be about an order of magnitude larger in the surface layer than in the bulk liquid phase. Furthermore, HCN molecules show a strong lateral self-association behavior at the liquid surface, forming thus floating HCN patches at the surface of their aqueous solutions. Moreover, HCN molecules are staying, on average, an order of magnitude longer at the liquid surface than water molecules, and this behavior is more pronounced at smaller HCN concentrations. Because of this enhanced dynamical stability, the floating HCN patches can provide excellent spots for polymerization of HCN, which can be the key step in the prebiotic synthesis of partially water-soluble adenine. All of these findings make the hypothesis of "HCN world" more plausible