343 research outputs found
Dynamics of supercooled confined water measured by deep inelastic neutron scattering
In this paper, we present the results of deep inelastic neutron scattering (DINS) measurements on supercooled water confined within the pores (average pore diameter ~ 20 Ã) of a disordered hydrophilic silica matrix obtained through hydrolysis and polycondensation of the alkoxide precursor Tetra-Methyl-Ortho-Silicate via the sol-gel method. Experiments were performed at two temperatures (250 K and 210 K, i.e., before and after the putative liquidâliquid transition of supercooled confined water) on a âwetâ sample with hydration h ~ 40% w/w, which is high enough to have water-filled pores but low enough to avoid water crystallization. A virtually âdryâ sample at h ~ 7% was also investigated to measure the contribution of the silica matrix to the neutron scattering signal. As is well known, DINS measurements allow the determination of the mean kinetic energy and the momentum distribution of the hydrogen atoms in the system and therefore, allow researchers to probe the local structure of supercooled confined water. The main result obtained is that at 210 K the hydrogen mean kinetic energy is equal or even slightly higher than at 250 K. This is at odds with the predictions of a semiempirical harmonic model recently proposed to describe the temperature dependence of the kinetic energy of hydrogen in water. This is a new and very interesting result, which suggests that at 210 K, the water hydrogens experience a stiffer intermolecular potential than at 250 K. This is in agreement with the liquidâliquid transition hypothesis
SAMBA E DESACATO EM SINHÔ: "REI" DO SAMBA, "REI" DA POLÊMICA
José Barbosa da Silva, J. Silva, ou Sinhô, alcunhado de Rei do samba, vaidoso, elegante, polêmico, contestador, foi um dos fundadores do samba urbano carioca e um dos responsáveis pela profissionalização, divulgação e comercialização do samba como produto e como gênero musical. Músico - pianista - conhecido e reconhecido nos ambientes onde o samba e a intriga fermentavam e borbulhavam nas décadas de 1910 e 1920, no Rio de Janeiro, compôs grandes preciosidades do cancioneiro nacional, ricas em sentimento poético, balanço rítmico e melodias de rápido sucesso. Polêmico, procurou, encontrou e viveu, no curso de pouco mais de dez anos, entre 1917 e 1930, interrompido pela morte prematura, por tuberculose, uma série de motivos e adversários para grandes polêmicas musicais e sobre direitos de composição. A polêmica que mais ficou conhecida e produziu maiores frutos foi aquela travada com os "baianos" da casa da Tia Ciata, objeto deste trabalho.Palavras-chave: Sinhô. Samba. Polêmica musical
RODA DE SAMBA, RODA DA VIDA: FILOSOFIA DE BOTEQUIM EM NOEL, PAULINHO E CHICO
Neste trabalho, busca-se demonstrar o conteúdo filosófico no pensamento miúdo do samba. Para isso, foram reunidos três “sambistas pensadores”, espécies de vetores de um modo típico de pensar a vida: Noel Rosa, Paulinho da Viola e Chico Buarque, que apresentam em suas obras legítima “filosofia de botequim”. Defende-se que esse modo típico de pensar foi gestado dentro das rodas de canto e com elas evoluiu até concretizar a metáfora do “botequim” como o ambiente propício a uma maneira sincopada de ação e pensamento. Palavras-chave: Filosofia de botequim. Noel Rosa. Paulinho da Viola. Chico Buarque. Rodas de samba. Pensamento sincopado
“Um samba em homenagem à nata da malandragem”: o samba malandro, de João da Bahiana a Chico Buarque
No mundo do samba, o malandro assumiu forma típica de comportamento, gingado, com base na síncopa característica do ritmo negro dos povos de origem banto. Essa forma de malandragem contribuiu para a evolução do gênero musical “samba”, por intermediar o diálogo entre a cultura tradicional do mundo reprimido, oprimido e perseguido dos negros pós-abolição da escravatura – fins do século XIX e início do século XX – e a nascente indústria cultural do mundo branco, com motivações capitalistas. O malandro do samba, no entanto, se investiu de características próprias e, dono do dom da palavra, de um discurso sedutor, porém caricato. É essa “conversa de malandro” que se focaliza neste trabalho, tendo como exemplos “Batuque na cozinha”, de João da Bahiana, e as canções sobre o malandro da peça Ópera do malandro, assinadas por Chico Buarque
Oxidación catalítica heterogénea de R-(+)-limoneno sobre catalizadores tipo Jacobsen
The development of heterogeneous catalytic processes is highly desirable in order to overcome somedrawbacks of homogeneous catalysts, such as the separation and recycling of these catalysts. In this work,we report that Jacobsen type catalysts are efficient and selective for the oxidation of R-(+)-limonene to itscorresponding diepoxides using in situ generated dimethyldioxirane (DMD) as oxidant. It was demonstratedthat the solid NaHCO3 addition to the initial reaction mixture, improves the catalytic activity. Additionally,catalyst samples can be recovered and reused at least twice without significant loss of its initial catalyticactivity.El desarrollo de procesos catalíticos heterogéneos es muy deseable dado que se pueden superar las dificultades que presentan los catalizadores homogéneos, tales como la separación y el reciclado de estos catalizadores. En este trabajo, reportamos que los catalizadores tipo Jacobsen son eficientes y selectivos
para la oxidación de R-(+)-limoneno a sus correspondientes diepóxidos cuando dimetildioxirano generado in situ es utilizado como agente oxidante. Se demostró que la adición de NaHCO3 sólido, al inicio de la reacción, mejora la actividad catalítica. Además, el catalizador puede ser recuperado y reutilizado al menos
dos veces sin pérdida significativa de su actividad catalítica inicial.Fil: Cubillos Lobo, Jairo Antonio. Universidad Pedagogica y Tecnologica de Colombia. Facultad de Ciencias. Escuela de Quimica; ColombiaFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigación y Desarrollo En Ciencias Aplicadas; ArgentinaFil: Paez Guevara, L. A.. Universidad Pedagogica y Tecnologica de Colombia. Facultad de Ciencias. Escuela de Quimica; Colombi
Advances in novel activation methods to perform green organic synthesis using recyclable heteropolyacid catalysis
Highly functionalized, high value added bioactive molecules are generally obtained by synthetic procedures that are highly selective, economical, with high atom economy, and environmentally friendly. Following these guidelines, the use of recoverable solid catalysts, nonpolluting substrates, or toxic organic solvent contributes greatly to these demands. In the last three decades, heteropolyacids (HPAs) and its derivatives have received great attention as recyclable solid catalysts, due to their strong Brönsted acidity, excellent oxidizing capacity under mild conditions, and various reuse cycles without appreciable loss of their catalytic activity. However, new activation methods should be investigated to improve the sustainability of a process using HPAs. In this review, we report the latest advances associated with the synthesis of potentially bioactive molecules using more energy efficient alternatives such as microwaves, ultrasound, mechanochemistry, and photochemistry to minimize the energy consumption associated with organic synthesis. The transformations studied include construction reaction, heterocycle synthesis, selective oxidation, and biomass recovery.Fil: Ruiz, Diego Manuel. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Cátedra de Química Orgánica; Argentina. Universidad Nacional de la Plata. Facultad de Cs.agrarias y Forestales. Centro de Investigacion En Sanidad Vegetal.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Pasquale, Gustavo Antonio. Universidad Nacional de la Plata. Facultad de Cs.agrarias y Forestales. Centro de Investigacion En Sanidad Vegetal.; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Cátedra de Química Orgánica; ArgentinaFil: Martínez, José J.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Romanelli, Gustavo Pablo. Universidad Nacional de la Plata. Facultad de Cs.agrarias y Forestales. Centro de Investigacion En Sanidad Vegetal.; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Cátedra de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin
Valorizacion de derivados de biomasa; produccion de levulinato de etilo con bajo impacto ambiental empleando un heteropoliacido de estructura Preyssler
El catalizador con estructura tipo Preyssler fue inmovilizado por primera vez mediante la técnica sol-gel en sílice. Este catalizador se utilizó en la esterificación del ácido levulínico con etanol, a 78 ºC para obtener levulinato de etilo. La reacción de esterificación entre el ácido levulínico y etanol, para producir levulinato de etilo, han demostrado que el PSiO incluido en la sílice HPA es activo y selectivo para esta reacción, mantuvo su estructura y actividad catalítica después de dos ciclos consecutivos de reacción. El procedimiento descrito permite reemplazara los catalizadores ácidos solubles usuales, contribuyendo a una reducción de la generación de residuos.Fil: Pasquale, Gustavo Antonio. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Catedra de Quimica Organica; ArgentinaFil: Ruiz, Diego Manuel. Universidad Nacional de la Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Catedra de Quimica Organica; ArgentinaFil: Sathicq, Angel Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigación y Desarrollo En Ciencias Aplicadas; ArgentinaFil: Baronetti, Graciela Teresita. Universidad de Buenos Aires. Facultad de Ingenieria. Departamento de Ingenieria Quimica. Laboratorio de Procesos Cataliticos; ArgentinaFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigación y Desarrollo En Ciencias Aplicadas; Argentin
Installation of a very broad band borehole seismic station in Ferrara (Emilia)
The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is the Italian agency devoted to monitor in real time the seismicity on the Italian territory. The seismicity in Italy is of course variable in time and space, being also very much dependant on local noise conditions. Specifically, monitoring seismicity in an alluvial basin like the Po one is a challenge, due to consistent site effects induced by soft alluvial deposits and bad coupling with the deep bedrock (Steidl et al., 1996). This problem was tackled by INGV first with the Cavola experiment (Bordoni et al., 2007), where a landslide was seismically characterized using a seismic array and also down-hole logging of P- and S-wave travel times at a borehole drilled within the array; later, with an ad hoc project in 2000-2001, with the first installation of a broad band seismic station nearby Ferrara in a borehole of 135 meters depth. Comparison of recordings with a surface seismic station indicated a noise reduction of 2 decades in power spectral density at frequencies larger than 1.0 Hz (Cocco et al., 2001). The instrumentation in Ferrara has been working for several months but after that the seismic station was discontinued due to lack of maintenance manpower.
The Centro di Ricerche Sismologiche (CRS, Seismological Research Center) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the Northeastern Italy (NI) Seismic Network: it currently consists of 15 very sensitive broad band and 21 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data center in Udine (Fig. 1).
Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of about 100 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of Northeastern Italy. Since 2002 OGS-CRS is using the Antelope software suite on several workstations plus a SUN cluster as the main tool for collecting, analyzing, archiving and exchanging seismic data, initially in the framework of the EU Interreg IIIA project “Trans-national seismological networks in the South-Eastern Alps”. SeisComP is also used as a real time data exchange server tool (Bragato et al., 2011).
Among the various Italian institution with which OGS is cooperating for real time monitoring of local seismicity there is the Regione Veneto (Barnaba et al., 2012). The Southern part of the Veneto Region stands on the Po alluvial basin: earthquake localization and characterization is here again affected in this area by the presence of soft alluvial deposits. OGS ha already experience in running a local seismic network in difficult noise conditions making use of borehole installations (Priolo et al., 2012) in the case of the monitoring of a local storage site for the Italian national electricity company ENEL. Following the ML=5.9 earthquake that struck the Emilia region around Ferrara in Northern Italy on May 20, 2012 at 02:03:53 UTC, a cooperation of INGV, OGS, the Comune di Ferrara and the University of Ferrara lead to the reinstallation of the very broad band borehole seismic station in Ferrara. The aim of the OGS intervention was on one hand to extend its real time seismic monitoring capabilities toward South-East (Fig. 1), including Ferrara and its surroundings, and on the other hand to evaluate the seismic response at the site.
As concerns the superficial geology of the area where the borehole seismic station has been installed, the outcropping materials are represented by alluvial deposits of different environments, like channel and proximal levee, inter-fluvial, meander and swamps deposits. As a consequence, the outcropping deposits are everywhere Holocene in age substantially loose or poorly compacted in the first meters-decameters and granulometrically could vary from clay to coarse sand.
Two preliminary reports prepared by the Italian Department of Civil Defense (Dipartimento Nazionale di Protezione Civile) in collaboration with other institutions describe the data recorded by the national accelerometric network and complemented by additional data recorded by a number of temporary stations (Dolce et al., 2012a; Dolce et al., 2012b). These reports bear witness of strong ground motion values with an acceleration peak of about 0.9 g in the vertical component recorded during the ML=5.8 earthquake of May 29, 2012 by the Mirandola station, located at about 2 km from the epicentre. The analysis of the seismic noise recorded at some stations shows a quite pronounced peak of the horizontal-to-vertical spectral ratio (H/V) in the frequency range of 0.6 – 0.9 Hz common to all stations. Finally, strong evidence of liquefaction phenomena are reported at several sites (e.g.: S. Carlo, S. Agostino and Mirabello), most of which have been attributed to the occurrence of saturated sandy layer(s) at shallow depth deposited along an abandoned reach of the Reno River (Papathanassiou et al., 2012).
Details of the station configuration and installation will be outlined, with first results
Adjustments, extinction, and remains of selenocysteine incorporation machinery in the nematode lineage
This article is distributed exclusively by the RNA Society for the first 12 months after the full-issue publication date. After 12 months, it is available under a Creative Commons License (Attribution-NonCommercial 4.0 International).Selenocysteine (Sec) is encoded by an UGA codon with the help of a SECIS element present in selenoprotein mRNAs. SECIS-binding protein (SBP2/SCBP-2) mediates Sec insertion, but the roles of its domains and the impact of its deficiency on Sec insertion are not fully understood. We used Caenorhabditis elegans to examine SBP2 function since it possesses a single selenoprotein, thioredoxin reductase-1 (TRXR-1). All SBP2 described so far have an RNA-binding domain (RBD) and a Secincorporation domain (SID). Surprisingly, C. elegans SBP2 lacks SID and consists only of an RBD. An sbp2 deletion mutant strain ablated Sec incorporation demonstrating SBP2 essentiality for Sec incorporation. Further in silico analyses of nematode genomes revealed conservation of SBP2 lacking SID and maintenance of Sec incorporation linked to TRXR-1. Remarkably, parasitic plant nematodes lost the ability to incorporate Sec, but retained SecP43, a gene associated with Sec incorporation. Interestingly, both selenophosphate synthetase (SPS) genes are absent in plant parasitic nematodes, while only Cys-containing SPS2 is present in Sec-incorporating nematodes. Our results indicate that C. elegans and the nematode lineage provide key insights into Sec incorporation and the evolution of Sec utilization trait, selenoproteomes, selenoproteins, and Sec residues. Finally, our study provides evidence of noncanonical translation initiation in C. elegans, not previously known for this well-established animal model.This work was supported by Universidad de la República, Uruguay (Grant Number 418 to G.S., PhD fellowship to L.O.); Asociación Española de Cooperación Internacional (C/7646/07 to A.M.-V. and G.S.; A/016083/08 to A.M.-V. and G.S.); Asociación Universitaria Iberoamericana de Posgrado and Agencia Nacional de Innovación e Investigación (BE_POS_2009_183 and BE_POS_2010_2160 to L.O.), and was partially funded by FOCEM (MERCOSUR Structural Convergence Fund), [COF 03/11].Peer Reviewe
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