1,448 research outputs found
Nonlinear optical properties of organo-metallic films
Projecte fet en col.laboració amb l'Institut de Ciències FotòniquesJoining organic molecules and metallic nanoparticles into coupled heterostruc-
tures allows tuning their optical properties and o®ers novel possibilities for manipulating their
emission patterns. This Master Thesis is aimed at probing and understanding the nature of
the optical coupling between plasmonic nanoparticles and organic molecules. We carry out
second harmonic spectroscopy and interferometry experiments on thin flms of the nonlinear
dye crystal violet deposited on glass and on top of silver nanoparticles to study the interplay
between the resonance of the dye and the plasmon modes of the nanoparticles. We find a
small redshift of second harmonic emission from the nanoparticles, while the molecular second harmonic resonance displays a large blueshift of tens of nanometers in the vicinity of the
nanoparticles. Across both resonances a characteristic shift of ¼ in the phase of the generated
second harmonic light is observed by second harmonic interferometry. To explain our ¯nd-
ings, a phenomenological model with two coupled damped anharmonic oscillators is proposed.
With the model, we are able to reproduce the main features of the experimental data
Current archaeological research at the Nutria Mansa locality: New contributions from ground stone tools studies
Las investigaciones desarrolladas en la localidad arqueológica Nutria Mansa (partidos de General Alvarado y Lobería) han aportado importante información para el estudio de los cazadores-recolectores pampeanos que ocuparon el litoral marítimo bonaerense a finales del Holoceno. En este trabajo se presenta el estado actual de los estudios sobre la base de nuevos resultados del análisis faunístico (determinaciones taxonómicas y anatómicas, cuantificación zooarqueológica) y lítico (pigmentos minerales, remontajes, identificación de materias primas). Asimismo, se estudian con especial énfasis los artefactos picados y/o abradidos de la localidad. Este conjunto artefactual incluye instrumentos de molienda, bolas de boleadoras, percutores, yunques, abradidores-pulidores y artefactos compuestos. Se utilizaron rocas de procedencia principalmente local, y otras de fuentes inmediatamente disponibles u obtenidas a larga distancia. La mayor parte de los instrumentos de molienda y todas las bolas de boleadoras fueron manufacturadas, mientras que en los percutores fue frecuente aprovechar formas-base naturales sin modificaciones previas al uso. Se destaca la alta presencia de múltiples caras activas en cada pieza en la mayoría del conjunto picado y/o abradidos. Se identificaron diferentes estrategias de mantenimiento y administración del desgaste, así como también evidencias del reciclaje de artefactos. El análisis de las diferentes evidencias arqueológicas de la localidad Nutria Mansa permite abordar las múltiples actividades desarrolladas en campamentos de cazadores-recolectores asentados en las cercanías al litoral marítimo bonaerense.Research on Nutria Mansa archaeological locality has yielded important data for the study of Pampean hunter-gatherers that inhabited the maritime coast of Buenos Aires Province during the Late Holocene. This paper presents the current state of studies in this archaeological locality. New results on faunal analysis (taxonomic and anatomical determinations) and lithic analysis (mineral pigments, refitting, and raw material identification) are presented. Ground stone tools (grinding tools, bola stones, hammerstones, anvils, abraders, and composite tools) are analyzed with particular emphasis. This assemblage was mainly made of local raw materials. Rocks from immediate or long distance sources were also exploited. Most of the grinding tools and all bolas stones were modified by manufacture. The use of unmodified blanks was frequent between the hammerstones. Multiple used surfaces were frequently registered. Maintenance tasks were identified, as well as the presence of recycled artifacts. The analysis of the different archaeological evidences from Nutria Mansa locality shows multiple activities developed in camps of hunter-gatherers groups located close to the maritime coast of Buenos Aires Province.Fil: Bonomo, Mariano. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Matarrese, Marina Laura. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin
Chemometric study of the excipients’ influence on polymorphic-behavior: Mefenamic acid as case of study
The assessment of polymorphism is a problematical issue for regulatory agencies, because variations among crystalline forms of active pharmaceutical ingredient (API) can lead to changes in the efficacy and safety of formulated product. Such conversions are very hard to be detected, thus, the development of techniques for the identification, characterization and quantification of polymorphs results essential in all stages of the manufacturing process. The presence of excipients in formulated products may change the crystal stability of an API, by catalyzing a polymorphic transformation or stabilizing the less stable form. As paradox, all suitable analytical techniques (spectroscopies, thermal analysis, NMR and DRX, and others) for polymorphic analysis are affected by excipients. A deep understanding of the polymorphism-excipient relationship is in full accordance with Quality by Design (QbD) paradigm, the systematic approach focused in quality building into a product based in the full understanding of the products and process. In this work, a novel approach based on thermal stress, MIR monitoring, multivariate curve resolution with alternating least squares (MCR-ALS) and kinetic analysis was developed and applied to monitor polymorphism behavior of model API in formulated products. Commercial tablets, physical mixtures and commercial API, were processed and analyzed under the proposed approach. Commercial tablets of MFA revealed a fast conversion to Form II, contrasting to the behavior of the pure API. Physical mixtures showed similar behavior to commercial tablets, thus reduction in transformation times was related to MFA-excipients physical interaction, even at surface level. Calorimetric studies support the conclusion obtained. The developed approach could be extended to others APIs and other stress sources (humidity, solvents, mechanical forces and its combinations), being a valuable tool for QbD environment.Fil: Antonio, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Calvo, Natalia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Maggio, Ruben Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin
Experiencia de Aviturismo en la Patagonia Argentina: Programa Balneario El Condor Cielo de Aves
La observación de aves es una de las experiencias turísticas-recreativas de naturaleza más difundidas y valoradas. El turismo de naturaleza es una actividad establecida a nivel mundial,movilizando en Argentina al 80% de sus visitantes. El Balneario El Cóndor (BEC) (41°3 S 62°48 W), Patagonia Argentina, es considerado un Área Importante para la Conservación delas Aves, debido a su gran diversidad de aves y a la presencia de la colonia de loros barranqueros (Cyanoliseus patagonus), considerada la mayor colonia de loros del mundo. El BEC resguarda remanentes de Monte y Espinal, ambientes con graves problemas de conservación. El presente trabajo expone los alcances del Programa Aviturístico Balneario El Cóndor Cielo de Aves durante la temporada estival 2013/2014, complementado con un análisis del perfil de los usuarios. Se diseñaron 4 senderos de avifauna: Aves de la playa, Aves del acantilado, Aves del Monte y las dunas y Aves del estuario y la marisma del Río Negro.Organizado por el Municipio de Viedma y con carácter libre y gratuito, se realizaron 21 visitas guiadas al sendero de aves del Monte y las dunas. Participaron 582 personas arrojando un promedio de 27,7 usuarios/salida. Sólo el 15,3 % de los mismos manifestaron haber realizado alguna actividad de observación de aves al menos una vez anteriormente. El 63,2% (n = 368)de los usuarios fueron turistas, procedentes de varios destinos de Argentina y extranjeros de América del Norte y Europa; mientras que el 36,8% (n = 214) fueron recreacionistas (vecinos de la comarca Viedma - Patagones). Más del 40 % de los asistentes tenían entre 21 y 50 años de edad. Sobre un total de 220 grupos de usuarios, se observó un promedio de 2,6 usuarios/grupo, siendo la mayoría grupos familiares. Fueron observadas 41 especies de aves pertenecientes a 10 órdenes y 22 familias, con un promedio de 16 especies de aves observadas/salida. Sobre 300 usuarios encuestados, el 93,3 % manifestó que la actividad cubrió sus expectativas. El desarrollo del aviturismo responsable en el BEC, permitirían la inclusión de este sitio en el circuito patagónico de destinos especializados en turismo de naturaleza, fomentando la conservación de su biodiversidad y ambientes. El Programa Balneario El Cóndor Cielo de Aves representa la primera experiencia de aviturismo masivo,libre y gratuito de la Patagonia Noreste. La mayor colonia de loros del mundo, sumado a la diversidad de vida silvestre y paisajes disponibles a solo minutos de los centros de servicios,podrían estructurar el desarrollo del turismo en el BEC.Birdwatching is one of the most widespread and valued of tourist-recreational nature experiences. Nature tourism is a worldwide activity, engaged in by 80% of international visitors to Argentina. The Balneario El Condor (BEC) (41° 3' S - 62° 48' W), Patagonia Argentina, is considered an Important Bird Area, because of its great diversity of birds. And also, because of the presence of its colony of Burrowing Parrots (Cyanoliseus patagonus), which is considered the largest colony of parrots in the world. The BEC protects its remnant areas of Monte and Espinal vegetation, both habitats with serious global conservation problems. This report explains the scope of the birdwatching program “Balneario El Condor - Cielo de Aves” during the summer season 2013/2014, complemented by an analysis of the participants. Four bird watching trails were designed: "Birds of the beach", "Birds of the cliffs", "Birds of the Monte and dunes" and "Birds of the salt marsh and estuary of the Río Negro River". Organized by the Municipality of Viedma, 21 (free) guided trips along the Birds of the Monte and dunes trail were made. 582 people participated for an average of 28 persons/trip. Only 15% of them said that they had been bird watching before coming to BEC. 63 percent (n = 368) of the participants were from other places in Argentina or from North America and Europe; while 37% (n = 214) were local residents from the Viedma - Patagones area. More than 40% of the participants were between 21 and 50 years old. There was an average of 2.6 persons in 220 surveyed groups, with most groups consisting of families. Forty-one species of birds were seen, belonging to 10 orders and 22 families. An average of 16 birds species were seen per trip. Of 300 users questioned, 93% said that the activity reached their expectations. Responsible birdwatching development in the BEC would promote the addition of this site to the Patagonian circuit that specializes in nature tourism destinations, and there by promote the conservation of the local biodiversity and environments. “Balneario El Condor - Cielo de Aves” represents the first massive, free birdwatching program in northeastern Patagonia. Emphasizing the presence of the largest parrot colony in the world, added to the diversity of wildlife and landscapes available within minutes of the service centers, could greatly enhance tourism to the BEC.Fil: Failla, Mauricio. Proyecto Patagonia Noreste; ArgentinaFil: Winter, Marina. Proyecto Patagonia Noreste; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Soricetti, Mariano. Proyecto Patagonia Noreste; ArgentinaFil: Llanos, Fabián Andrés. Proyecto Patagonia Noreste; Argentin
MIR135A1 (microRNA 135a-1)
Review on MIR135A1, with data on DNA/RNA and where the gene is implicated
A field comparison of different olive (Olea europaea L.) cultivars as host of the ash whitefly Siphoninus phillyreae (Haliday)
La mosca blanca del fresno, Siphoninus
phillyreae (Haliday) , es una especie polífaga invasiva que causa graves daños
en sus hospedadores, entre ellos el olivo
(Olea europaea L.). El uso del hospedador
por parte de S. phillyreae fue observado en
tres cultivares de olivo (Arauco, Arbequina y
Aloreña) en el norte de la provincia de La Rioja
(Argentina) durante 2007 y 2008. De cada
cultivar se muestrearon seis plantas infestadas
y de cada planta se tomaron ocho hojas.
De cada hoja se registró la abundancia de
adultos y estados inmaduros de la mosca blanca
que fueron comparadas entre los cultivares
mediante modelos lineales generales y mixtos.
Los resultados obtenidos mostraron diferencias
significativas entre las densidades de adultos y
ninfas de S. phillyreae en los distintos cultivares
de olivo analizados. Dichos resultados indican
que este insecto realiza un uso diferente de los
cultivares de olivo, siendo Arauco y Arbequina
las variedades hospedadoras más utilizadas en
la zona de estudio.The ash whitefly, Siphoninus phillyreae
(Haliday) is an invasive polyphagous species
that causes serious damage to their hosts,
including olive (Olea europaea L.). Host use
by S. phillyreae was observed in three olive
cultivars (Arauco, Arbequina y Aloreña) in
North of La Rioja province (Argentina) during
2007 and 2008. Eight leaves of six infested
plants of each cultivar were sampled. Adults
and inmature stages abundances of each
leaf were recorded. These abundances per
cultivar were compared using general linear
mixed model. The results showed significant
differences between the densities of adults
and nymphs of S. phillyreae in each of the olive
cultivars analyzed. Thus, our results indicate
that this insect makes a different use of the olive
cultivars, Arauco and Arbequina being the most
used in the study area.Fil: Pedemonte, María Laura.
Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales.Fil: Bruno, Marina Anabel.
Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales.Fil: Grilli, Mariano Pablo.
Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales
Physical Education In Early Childhood Education: Educating Children Or Boys And Girls?
Este artigo trata das relações de gênero em aulas de Educação Física na Educação Infantil. A metodologia empregada na pesquisa que o originou consistiu na realização de observações de aulas e entrevistas com um professor e uma professora que lecionam em escolas públicas de um município da Região Metropolitana de Campinas, SP, Brasil. Expectativas e incentivos docentes, quando expressas para as crianças de forma polarizada, produziram desigualdades de gênero. Intervenções menos polarizadas produziram relações de gênero menos hierarquizadas e desiguais entre as crianças, constituindo meninos e meninas como capazes de aprender e vivenciar o corpo e os gestos de forma ampla e diversificada.4641143
Light harvesting in fiber array organic solar cells
Considering that the most abundant renewable energy source is the Sun, photovoltaic technology possesses one of the highest potentials to provide environmental benign and sustainable energy worldwide. Currently, most of commercial available modules are fabricated from crystalline silicon because of its high efficiency. To lower fabrication costs and increase the functionality of the solar modules, several thin film technologies are under development. Among them, organic photovoltaics has created large expectations provided it possesses some intrinsic advantages, such as light weight, flexibility or semi-transparency.
However, the low charge mobility in the majority of the organic semiconductor materials prevents the use of active layers thicker than a few hundred nanometers. This leads to a limited light harvesting capacity and, consequently, a limited conversion efficiency. Different optical approaches have been considered to enhance the absorption of organic solar cells and increase their efficiency. In this thesis, we propose a novel configuration based on the use of fiber arrays to effectively trap light and efficiently couple it into the active layer to enhance absorption.
The thesis work is presented in five chapters. After an introductory chapter, in chapter 2 light absorption of an organic solar cell deposited on the backside of a fiber array is studied theoretically. A strong enhancement in light harvesting is predicted using such configuration. For small diameter fibers the enhancements originated from light coupling to some low quality whispering gallery modes, while for large diameter fibers light seemed to be effectively trapped inside the fiber structure.
In chapter 3 and 4, we consider the dip-coating procedure, a fabrication technique that can be applied to deposit from a precursor solution, layers on a substrate irrespective of its shape. Its viability is demonstrated by applying it to different device architectures. The deposition on such non-flat substrates of the rest of the layers forming an organic solar cell is also examined. For instance, several relevant changes that had to be introduced to the ITO sputtering to obtain transparent electrodes with an optimal quality, both, optically and electrically, are discussed.
Once the layer deposition is optimized to fulfill the electrical and optical requirements of organic solar cells, in chapter 5, we experimentally demonstrate that an enhanced light absorption can be achieved from such organic solar cells when deposited on fiber arrays. Optical fibers of 80 µm in diameter were used to fabricate the arrays to be used as the cell substrate. Such substrates were coated with an organic solar cell of evaporated small molecules. The implemented fiber array configuration is seen to be an effective light trapping method. Indeed, the photogenerated current from such devices is shown to increase by a 26%, which is a considerable percentage when compared to the majority of the optical approaches that were considered in the past to enhance absorption in organic cells.Si considerem que la font d'energia renovable més a abundant és el Sol, la tecnologia fotovoltaica posseeix un dels potencials més alts per poder produir l'energia mundial de forma sostenible i benigne amb el medi ambient. Actualment la majoria dels mòduls comercials estan fabricats de silici cristal.lí ja que aquest material té una gran eficiència. Per tal de rebaixar els costos de producció i incrementar la funcionalitat d'aquest panells solars, diverses tecnologies de capa prima s'estan desenvolupant. Entre elles, la tecnologia fotovoltaica amb materials orgànics ha creat grans expectatives gràcies a les seves propietats intrínseques, com per exemple la seva lleugeresa, flexibilitat o bé semi transparència. Per altra banda, la baixa mobilitat de les càrregues en la majoria dels semiconductors orgànics impedeix l'ús de capes actives no molt més gruixudes que uns pocs nanòmetres. Això provoca que tinguin una capacitat de col.lecció lumínica limitada i com a conseqüència, la eficiència de conversió energètica també ho és. S'han considerat diferents estratègies òptiques per tal de millorar l'absorció en les cel.les solars orgàniques i incrementar la seva eficiència. En aquesta tesi proposem una configuració innovadora basada en l'ús d'una matriu de fibres, les quals atrapen i acoblen la llum en la capa activa per millorar l'absorció d'aquesta. La present tesi consta de cinc capítols. Després d'un capítol introductori, en el capítol 2 s'estudia teòricament l'absorció de llum d'una cel·la solar orgànica dipositada en la part posterior de la matriu de fibres. Per diàmetres de fibra petits, les millores són degudes a l'acoblament d'uns modes recirculants de llum de baixa qualitat. Mentre que per diàmetres grans, la llum sembla estar atrapada de forma efectiva dins de l'estructura formada per les fibres. En els capítols 3 i 4 hem considerat el recobriment per immersió, aquesta tècnica de fabricació pot ser aplicada per dipositar capes des d'una solució precursora a un substrat, independentment de la seva forma. La validesa de la tècnica es demostra quan s'aplica a diferents arquitectures de cel·la. El dipòsit en aquestes estructures no planes de la resta de les capes que formen la cel·la solar orgànica també s'ha investigat. Per exemple, es discuteixen varis canvis rellevants, els quals s'han tingut que introduir per la polvorització catòdica del ITO, per tal d'obtenir elèctrodes transparents amb unes qualitats òptiques i elèctriques òptimes
Physical Education in Early Childhood Education: Educating Children or Boys and Girls?
The article deals with gender relations in Physical Education classes in Early Childhood Education. The methodology involves performing class observations and interviews with a male teacher and a female teacher, who teach at public schools in a municipality of the Metropolitan Region of Campinas, SP, Brazil. Expectations and teachers incentives, when expressed in a polarized manner, produce gender inequalities. Less polarized interventions produced less hierarchical and unequal gender relations, forming boys and girls as being capable of learning and experiencing the body and gestures in a broad and diversified way.Este artigo trata das relações de gênero em aulas de Educação Física na Educação Infantil. A metodologia empregada na pesquisa que o originou consistiu na realização de observações de aulas e entrevistas com um professor e uma professora que lecionam em escolas públicas de um município da Região Metropolitana de Campinas, SP, Brasil. Expectativas e incentivos docentes, quando expressas para as crianças de forma polarizada, produziram desigualdades de gênero. Intervenções menos polarizadas produziram relações de gênero menos hierarquizadas e desiguais entre as crianças, constituindo meninos e meninas como capazes de aprender e vivenciar o corpo e os gestos de forma ampla e diversificada.04641143
Spatial and temporal variation of the different developmental stages of the sweet potato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in soybean
La soja es actualmente el cultivo más importante en la Argentina; a sus plagas tradicionales se ha sumado la mosca blanca, Bernisia tabaci. Los objetivos de este trabajo fueron establecer la distribución espacial de los diferentes estados de desarrollo (huevos, ninfas, pupas y adultos) de B. tabaci en lotes de soja del área central de la provincia de Córdoba (Argentina) y determinar la variación temporal de la abundancia de esos estados en dicha área. Se trabajó con muestras de lotes de dos localidades, Colonia Tirolesa y Colonia Caroya (Dpto. Colón). La comparación de abundancia entre localidades mostró variaciones entre ellas pero sólo se detectaron diferencias significativas entre adultos. Al comparar la variación de las abundancias entre fechas, sólo fue significativamente superior el aumento de ninfas y pupas durante la segunda fecha; en cuanto a los adultos se obtuvo mayor número durante la segunda fecha en Colonia Tirolesa. Cuando se analizó la variación de la abundancia tanto de inmaduros como de adultos se observaron diferencias significativas entre lotes para ambas localidades y para ambas fechas. Los resultados aquí presentados resultan de interés para ser utilizados en la toma de decisiones para el manejo de esta plaga.Soybean is now-a-days the most important crop in Argentina. Among all insect pests affecting this crop the sweetpotato whitefly, Bemisia tabaci, is becoming a new and increasingly important pest. In this paper we propose as objectives: a) to establish the spatial distribution of the different stages of B. tabaci in soybean plots in the central area of Cordoba province (Argentina) and b) to determine the spatio-temporal variation of the abundance of these stages in the same places. We worked with samples collected in to localities of Colon Department; Colonia Tirolesa and Colonia Caroya. The comparisons between localities showed a high variability between them but only the differences between adults were statistically significative. When we compared the variation of the abundance between sampling dates only the increase of nymphs and pupae were significative during the second sampling date in Colonia Tirolesa. When comparing the differences between soybean plots differences between plots in both localities and in all B. tabaci stages were observed. These results are an important input to be use in decision making for the management of this pest in the area.Fil: Cavallo, M. J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (p). Grupo Vinculado Centro de Relevamiento y Evaluacion de Recursos Agricolas y Naturales; ArgentinaFil: Bruno, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (p). Grupo Vinculado Centro de Relevamiento y Evaluacion de Recursos Agricolas y Naturales; ArgentinaFil: Irastorza, R.. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Grilli, Mariano Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (p). Grupo Vinculado Centro de Relevamiento y Evaluacion de Recursos Agricolas y Naturales; Argentin
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