2,062 research outputs found

    Novos restos de Notosuchus terrestris Woodward, 1896 (Crocodyliformes: Mesoeucrocodylia) do Cretåceo Superior de Neuquén, PatagÎnia, Argentina

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    New materials of Notosuchus terrestris are here described. They were found on Bajo de la Carpa Formation outcrops, near the Universidad Nacional del Comahue, NeuquĂ©n City. Descriptions were based on five specimens, one of them the only specimen of Notosuchus with postcranial remains articulated to the skull. As in Sphagesaurus, it presents triangular teeth in cross-section and oblique molariforms with worn facet surface. As in Mariliasuchus, it possesses procumbent mandibular incisiform teeth and, like in other notosuchians and basal crocodyliforms, it was able of proal mandibular movement. The centra of cervical vertebrae possess ventral keel as in Chimaerasuchus. Elongated cervical neural spines and suprapostzygapophyseal laminae in cervicodorsal vertebrae are observed. The scapular dorsal end is greatly enlarged, while the coracoid ventromedial process end is moderately developed. The dorsal surface of the ilium is lateromedially wide with a greatly expanded acetabular roof and a prominent anteromedial process in the femoral shaft. Based on diverse cranial and postcranial characters, we infer that Notosuchus possessed facial and perioral musculature well developed and an herbivore diet, confirming the suggestions of previous authors. Notosuchus represents, based on phylogenetic studies, the sister taxon of Mariliasuchus and the monophyly of Notosuchia is demonstrated. Paleobiogeographycally, the occurrence of Chimaerasuchus in China evidences the faunistic interchange between Gondwana and Central Asia during the Early Cretaceous.Novos materiais de Notosuchus terrestris sĂŁo aqui descritos. Eles provĂȘm de afloramentos da Formação Bajo de la Carpa, localizados prĂłximos Ă  Universidad Nacional del Comahue, na cidade de NeuquĂ©n. As descriçÔes foram baseadas em cinco exemplares, um deles o Ășnico espĂ©cime de Notosuchus com restos pĂłs-cranianos articulados ao crĂąnio. Como em Sphagesaurus, N. terrestris apresenta dentes triangulares em seção cruzada e molariformes oblĂ­quos com superfĂ­cie da faceta com desgaste. Como em Mariliasuchus, a espĂ©cie possui dentes mandibulares incisiformes procumbentes e, como em outros notossĂșquios e crocodiliformes basais, era possĂ­vel realizar o movimento antero-posterior mandibular. Os centros das vĂ©rtebras cervicais possuem uma quilha ventral como em Chimaerasuchus. Espinhos neurais cervicais alongados e lĂąminas suprapĂłszigapofiseais em vĂ©rtebras cĂ©rvico-dorsais sĂŁo observados. A extremidade escapular dorsal Ă© amplamente alargada, enquanto a extremidade do processo ventro-medial do coracĂłide Ă© pouco desenvolvida. A superfĂ­cie dorsal do ilium Ă© larga lĂĄtero-medialmente com um teto acetabular amplamente expandido e processo Ăąntero-medial proeminente na diĂĄfise femoral. Baseado em diversos caracteres cranianos e pĂłs-cranianos, infere-se que Notosuchus apresentava grande desenvolvimento da musculatura facial e perioral e tinha uma dieta herbĂ­vora, confirmando o que foi sugerido anteriormente por outros autores. Notosuchus representa, baseado em estudos filogenĂ©ticos, o tĂĄxon irmĂŁo de Mariliasuchus e a monofilia de Notosuchia Ă© demonstrada. Paleobiogeograficamente, a ocorrĂȘncia de Chimaerasuchus na China evidencia o intercĂąmbio faunĂ­stico entre o Gondwana e a Ásia Central durante o CretĂĄceo Inferior.Fil: Fiorelli, Lucas Ernesto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja. - SecretarĂ­a de Industria y MinerĂ­a. Servicio GeolĂłgico Minero Argentino. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja; Argentina. Universidad Nacional del Comahue. Centro PaleontolĂłgico Lago Barreales; ArgentinaFil: Calvo, Jorge. Universidad Nacional del Comahue. Centro PaleontolĂłgico Lago Barreales; Argentin

    The first “Protosuchian” (Archosauria: Crocodyliformes) from the Cretaceous (Santonian) of Gondwana

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    El primer “protosuquio” (Archosauria: Crocodyliformes) del CretĂĄcico (Santoniano) de Gondwana. Los restos de “protosuquios” del CretĂĄcico provienen, a excepciĂłn del “crocodyliforme de Las Hoyas” del CretĂĄcico Inferior de España, exclusivamente de Asia Central: Zaraasuchus, Gobiosuchus, Zosuchus y Artzosuchus del CretĂĄcico Superior de Mongolia; Tagarosuchus del CretĂĄcico Inferior del sur de Siberia; Edentosuchus, Sichuanosuchus y Shantungosuchus del CretĂĄcico Inferior de China. AquĂ­ reportamos un nuevo taxĂłn de crocodyliforme basal, Neuquensuchus universitas gen.nov., sp.nov., de la provincia de NeuquĂ©n, Argentina, correspondiente a la FormaciĂłn Bajo de la Carpa, representando el primer y Ășnico “protosuquio” del CretĂĄcico de Gondwana. Los materiales fragmentarios y articulados corresponden a una especie esbelta y delgada, con extremidades largas y delgadas. Al igual que en Shantungosuchus, los centros cervicales son alargados, con una quilla ventral prominente y parapĂłfisis anteroventrales bien desarrolladas. Como en los crocodyliformes basales, Neuquensuchus posee dos vĂ©rtebras sacras. AdemĂĄs, una hoja escapular muy expandida, con un puente acromial bien desarrollado y el borde posterior similar a Sichuanosuchus. La cresta deltopectoral pronunciada en el hĂșmero es equivalente a la de Sichuanosuchus y al igual que este, la diĂĄfisis es circular, alargada y delgada con el cĂłndilo medial mayor que el lateral. Asimismo, las proporciones del radio y la Ășlna son similares a Sichuanosuchus. Como este, el pubis es alargado, muy delgado en su secciĂłn media y poco expandido distalmente. El fĂ©mur, tibia y fĂ­bula son alargados y similares a otros crocodyliformes no derivados. AdemĂĄs de representar el primer “protosuquio” cretĂĄcico de Gondwana, su presencia fuera de Asia y Europa durante el CretĂĄcico ofrece nueva evidencia de un evento de dispersiĂłn pre-Albiano entre Gondwana y Asia Central a travĂ©s de Europa.The remains of “protosuchians” from the Cretaceous come, to exception of “Las Hoyas crocodyliform” from the Lower Cretaceous of Spain, exclusively of Central Asia: Zaraasuchus, Gobiosuchus, Zosuchus, and Artzosuchus from the Upper Cretaceous of Mongolia; Tagarosuchus from Lower Cretaceous of Southern Siberia; Edentosuchus, Sichuanosuchus, and Shantungosuchus from Lower Cretaceous of China. We report a new basal crocodyliform taxon, Neuquensuchus universitas gen.nov., sp.nov., from NeuquĂ©n Province, Argentina, belonging to Bajo de la Carpa Formation, representing the first and only “protosuchian” from the Cretaceous of Gondwana. The articulated and fragmentary materials belonged to a willowy, slender species, with very long and thin extremities. As in Shantungosuchus, the cervical centers are lengthened, with prominent ventral keel and well developed anteroventral parapophyses. As in basal crocodylomorphs, it possesses two sacral vertebrae. Also, a much enlarged scapular blade, with well developed acromial ridge and the posterior edge similar to Sichuanosuchus. The pronounced deltopectoral crest in the complete humerus is equivalent to Sichuanosuchus and as this, a circular, elongated and thin shaft with the medial condyle longer than the lateral one. Also, the complete ulna and radius is similar in their proportions to Sichuanosuchus. As this, the pubis is lengthened, very thin in the half section and not very expanded distally. The femur, tibia and fibula are elongated and similar to other non-derivated crocodyliforms. Besides representing the first Cretaceous “protosuchian” of Gondwana, the occurrence of these outside of Asia and Europe during the Cretaceous offers new evidence of pre-Albian dispersion between Gondwana and Central Asia through Europe.Fil: Fiorelli, Lucas Ernesto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja. - SecretarĂ­a de Industria y MinerĂ­a. Servicio GeolĂłgico Minero Argentino. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones CientĂ­ficas y Transferencia TecnolĂłgica de La Rioja; ArgentinaFil: Calvo, Jorge Orlando. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Universidad Nacional del Comahue. Centro PaleontolĂłgico Lago Barreales; Argentin

    Sudden Stop, Financial Factors and Economic Collpase in Latin America: Learning from Argentina and Chile

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    This paper shows that the Russian 1998 crisis had a big impact on capital flows to Emerging Market Economies, EMs, especially in Latin America, and that the impact of the Russian shock differs quite markedly across EMs. To illustrate this statement, we compare the polar cases of Chile and Argentina. While Chile exhibited a significant economic slowdown after August 1998, it did not suffer the excruciating collapse suffered by Argentina, where even the payments system came to a full stop. We attribute their difference to the fact that Chile is more open to trade than Argentina, and that it appears to suffer much less from balance-sheet currency-denomination mismatch that was rampant in Argentina before the 2002 crisis (due to large domestic liability dollarization). The paper is essentially descriptive but is in line with and, thus, complements econometric studies like Calvo, Izquierdo and Mejia (NBER Working Paper 10520). The final section addresses policy issues in light of the paper's findings and conjectures.

    Sudden Stops, the Real Exchange Rate, and Fiscal Sustainability: Argentina's Lessons

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    We offer an alternative explanation for the fall of Argentina's Convertibility Program based on the country's vulnerability to Sudden Stops in capital flows. Sudden Stops are typically accompanied by a substantial increase in the real exchange rate that breaks havoc in countries that are heavily dollarized in their liabilities, turning otherwise sustainable fiscal and corporate sector positions into unsustainable ones. In particular, we stress that the required change in relative prices is larger the more closed an economy is in terms of its supply of tradable goods. By contrasting Argentina's performance relative to other Latin American countries that were also subject to the Sudden Stop triggered by the Russian crisis of 1998, we identify key vulnerability indicators that separated Argentina from its piers. We also provide an explanation for the political maelstrom that ensued after the Sudden Stop, based on a War of Attrition argument related to the wealth redistribution conflict triggered by the Sudden Stop and fiscal collapse. This framework also provides elements to rationalize the banking crisis that accompanied the fall of Convertibility.

    Phoenix Miracles in Emerging Markets: Recovering without Credit from Systemic Financial Crises

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    Using a sample of emerging markets that are integrated into global bond markets, we analyze the collapse and recovery phase of output collapses that coincide with systemic sudden stops, defined as periods of skyrocketing aggregate bond spreads and large capital flow reversals. Our findings indicate the presence of a very similar pattern across different episodes: output recovers with virtually no recovery in either domestic or foreign credit, a phenomenon that we call a Phoenix Miracle, where output rises from its ashes, suggesting that firms go through a process of financial engineering to restore liquidity outside formal credit markets. Moreover, we show that the U. S. Great Depression could be catalogued as a Phoenix Miracle. However, in contrast to the U. S. Great Depression, EM output collapses occur in a context of accelerating price inflation and falling real wages, casting doubt on price deflation and nominal wage rigidity as key elements in explaining output collapse, and suggesting that financial factors figure prominently in these collapses.

    Phoenix Miracles in Emerging Markets: Recovering without Credit from Systemic Financial Crises

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    Using a sample of emerging markets that are integrated into global bond markets, we analyze the collapse and recovery phase of output collapses that coincide with systemic sudden stops, defined as periods of skyrocketing aggregate bond spreads and large capital flow reversals. Our findings indicate the presence of a very similar pattern across different episodes: output recovers with virtually no recovery in either domestic or foreign credit, a phenomenon that we call Phoenix Miracle, where output %u201Crises from its ashes%u201D, suggesting that firms go through a process of financial engineering to restore liquidity outside the formal credit markets. Moreover, we show that the US Great Depression could be catalogued as a Phoenix Miracle. However, in contrast to the US Great Depression, EM output collapses occur in a context of accelerating price inflation and falling real wages, casting doubts on price deflation and nominal wage rigidity as key elements in explaining output collapse, and suggesting that financial factors are prominent for understanding these collapses.

    Direct Lithium Recovery from Aqueous Electrolytes with Electrochemical Ion Pumping and Lithium Intercalation

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    In this mini-review, we provide an account of recent developments on electrochemical methods for the direct extraction of lithium (DEL) from natural brines, geothermal fluids, seawater, and battery recycling electrolytes by ion-pumping entropy cells. A critical discussion of selected examples with the LiMn2O4 lithium intercalation battery cathode material is presented, with emphasis on the operation parameters, some experimental results and multiscale simulations, some limitations and challenges, and conditions for industrial scaleup.Fil: Calvo, Ernesto Julio. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a; Argentin

    Paradas repentinas, tipo de cambio real y viabilidad fiscal: enseñanzas de Argentina

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    (Disponible en idioma inglĂ©s Ășnicamente) Presentamos una explicaciĂłn alternativa de la caĂ­da del programa de convertibilidad de Argentina, basĂĄndonos en la vulnerabilidad del paĂ­s a las paradas repentinas de los flujos de capitales. Las paradas repentinas por lo general van acompañadas de un incremento considerable del tipo de cambio real, lo que provoca el caos en paĂ­ses con pasivos considerablemente dolarizados y hace insostenibles posiciones fiscales y del sector privado por lo demĂĄs sostenibles. Subrayamos en particular que la variaciĂłn necesaria de los precios relativos es mayor mientras mĂĄs cerrada sea una economĂ­a en tĂ©rminos de su oferta de bienes transables. Al contrastar el desempeño de Argentina con el de otros paĂ­ses latinoamericanos que tambiĂ©n estuvieron sometidos a la parada repentina provocada por la crisis de Rusia en 1998, identificamos indicadores claves de vulnerabilidad que distinguieron a Argentina de sus pares. TambiĂ©n ofrecemos una explicaciĂłn del torbellino polĂ­tico que se produjo a continuaciĂłn de la parada repentina, basĂĄndonos en un argumento de guerra de desgaste y colapso fiscal. Este marco tambiĂ©n aporta elementos para racionalizar la crisis bancaria que acompañó la caĂ­da de la convertibilidad.

    The AD detector array: a new tool for studying diffractive physics at the ALICE experiment

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    We present a new detector array proposal for the ALICE experiment at LHC. This new subdetector is composed of four stations of scintillator pads and its main goal is to extend our current rapidity coverage. Therefore, we would have more sensitivity to tag the rapidity gaps related to the diffractive processes. In particular, we show a study of the performance of this new subdetector and its impact in our ability to select diffractive events. Certainly, this new system will contribute to improve the ALICE capabilities in addressing several subjects on diffractive physics.Tesi

    Lithium solvation in dimethyl sulfoxide-acetonitrile mixtures

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    We present molecular dynamics simulation results pertaining to the solvation of Li+ in dimethyl sulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-air batteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences in ionic size and charge sign, the solvation of Li+ is compared to the ones observed for infinitely diluted K+ and Cl− species, in similar solutions. At all compositions, the cations are preferentially solvated by dimethyl sulfoxide. Contrasting, the first solvation shell of Cl− shows a gradual modification in its composition, which varies linearly with the global concentrations of the two solvents in the mixtures. Moreover, the energetics of the solvation, described in terms of the corresponding solute-solvent coupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were found for the stabilization of different ionic species in solution, compared to the ones exhibited by their electrically neutral counterparts. These tendencies account for the characteristics of the free energy associated to the stabilization of Li+Cl−, contact-ion-pairs in these solutions. Ionic transport is also analyzed. Dynamical results show concentration trends similar to those recently obtained from direct experimental measurements.Fil: Semino, Rocio. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a; ArgentinaFil: Zaldivar, Gervasio. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a; ArgentinaFil: Calvo, Ernesto Julio. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a; ArgentinaFil: Laria, Daniel Hector. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂ­mica, FĂ­sica de los Materiales, Medioambiente y EnergĂ­a; Argentina. ComisiĂłn Nacional de EnergĂ­a AtĂłmica; Argentin
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