998 resultados para D. B. Elkonin


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Prickly acacia (Vachellia nilotica subsp. indica), a native of the Indian subcontinent, is a serious weed of the grazing areas of northern Australia and is a target for classical biological control. Native range surveys in India identified a leaf webber, Phycita sp. (Lepidoptera: Pyralidae) as a prospective biological control agent for prickly acacia. In this study, we report the life cycle and host-specificity test results Phycita sp. and highlight the contradictory results between the no-choice tests in India and Australia and the field host range in India. In no-choice tests in India and Australia, Phycita sp. completed development on two of 11 and 16 of 27 non-target test plant species, respectively. Although Phycita sp. fed and completed development on two non-target test plant species (Vachellia planifrons and V. leucophloea) in no-choice tests in India, there was no evidence of the insect on the two non-target test plant species in the field. Our contention is that oviposition behaviour could be the key mechanism in host selection of Phycita sp., resulting in its incidence only on prickly acacia in India. This is supported by paired oviposition choice tests involving three test plant species (Acacia baileyana, A. mearnsii and A. deanei) in quarantine in Australia, where eggs were laid only on prickly acacia. However, in paired oviposition choice trials, only few eggs were laid, making the results unreliable. Although oviposition choice tests suggest that prickly acacia is the most preferred and natural host, difficulties in conducting choice oviposition tests with fully grown trees under quarantine conditions in Australia and the logistic difficulties of conducting open-field tests with fully grown native Australian plants in India have led to rejection of Phycita sp. as a potential biological control agent for prickly acacia in Australia.

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Segmentation defects of the vertebrae (SDV) are caused by aberrant somite formation during embryogenesis and result in irregular formation of the vertebrae and ribs. The Notch signal transduction pathway plays a critical role in somite formation and patterning in model vertebrates. In humans, mutations in several genes involved in the Notch pathway are associated with SDV, with both autosomal recessive (MESP2, DLL3, LFNG, HES7) and autosomal dominant (TBX6) inheritance. However, many individuals with SDV do not carry mutations in these genes. Using whole-exome capture and massive parallel sequencing, we identified compound heterozygous mutations in RIPPLY2 in two brothers with multiple regional SDV, with appropriate familial segregation. One novel mutation (c.A238T:p.Arg80*) introduces a premature stop codon. In transiently transfected C2C12 mouse myoblasts, the RIPPLY2 mutant protein demonstrated impaired transcriptional repression activity compared with wild-type RIPPLY2 despite similar levels of expression. The other mutation (c.240-4T>G), with minor allele frequency <0.002, lies in the highly conserved splice site consensus sequence 5' to the terminal exon. Ripply2 has a well-established role in somitogenesis and vertebral column formation, interacting at both gene and protein levels with SDV-associated Mesp2 and Tbx6. We conclude that compound heterozygous mutations in RIPPLY2 are associated with SDV, a new gene for this condition. © The Author 2014.

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A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN.

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Boron addition to conventional titanium alloys below the eutectic limit refines the cast microstructure and improves mechanical properties. The present work explores the influence of hypoeutectic boron addition on the microstructure and texture evolution in Ti-6Al-4V alloy under beta extrusion. The beta extruded microstructure of Ti-6Al-4V is characterized by shear bands parallel to the extrusion direction. In contrast, the extruded Ti-6Al-4V-0.1B alloy shows a regular beta worked microstructure consisting of fine prior beta grains and acicular alpha-lamellae with no signs of the microstructural instability. Crystallographic texture after extrusion was almost identical for the two alloys indicating the similarity in their transformation behavior, which is attributed to complete dynamic recrystallization during beta processing. Microstructural features as well as crystallographic texture indicate dominant grain boundary related deformation processes for the boron modified alloy that leads to homogeneous deformation without instability formation. The absence of shear bands has significant technological importance as far as the secondary processing of boron added alloys in (alpha + beta)-phase field are concerned. (C) 2012 Elsevier B.V. All rights reserved.

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The interaction of a single bubble with a single vortex ring in water has been studied experimentally. Measurements of both the bubble dynamics and vorticity dynamics have been done to help understand the two-way coupled problem. The circulation strength of the vortex ring (Gamma) has been systematically varied, while keeping the bubble diameter (D-b) constant, with the bubble volume to vortex core volume ratio (V-R) also kept fixed at about 0.1. The other important parameter in the problem is a Weber number based on the vortex ring strength. (We = 0.87 rho(Gamma/2 pi a)(2)/(sigma/D-b); a = vortex core radius, sigma = surface tension), which is varied over a large range, We = 3-406. The interaction between the bubble and ring for each of the We cases broadly falls into four stages. Stage I is before capture of the bubble by the ring where the bubble is drawn into the low-pressure vortex core, while in stage II the bubble is stretched in the azimuthal direction within the ring and gradually broken up into a number of smaller bubbles. Following this, in stage III the bubble break-up is complete and the resulting smaller bubbles slowly move around the core, and finally in stage IV the bubbles escape. Apart from the effect of the ring on the bubble, the bubble is also shown to significantly affect the vortex ring, especially at low We (We similar to 3). In these low-We cases, the convection speed drops significantly compared to the base case without a bubble, while the core appears to fragment with a resultant large decrease in enstrophy by about 50 %. In the higher-We cases (We > 100), there are some differences in convection speed and enstrophy, but the effects are relatively small. The most dramatic effects of the bubble on the ring are found for thicker core rings at low We (We similar to 3) with the vortex ring almost stopping after interacting with the bubble, and the core fragmenting into two parts. The present idealized experiments exhibit many phenomena also seen in bubbly turbulent flows such as reduction in enstrophy, suppression of structures, enhancement of energy at small scales and reduction in energy at large scales. These similarities suggest that results from the present experiments can be helpful in better understanding interactions of bubbles with eddies in turbulent flows.

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Contenido: El aristotelismo y el tomismo frente al egoísmo psicológico / María L. Lukac de Stier – El deseo natural de ver a Dios en la Summa contra Gentiles / Guillermo Jorge Cambiasso – La creación como encuentro del ser y de la nada en la teología del maestro Eckhart de Hochheim O.P. (1260-1327) / Brian J. Farrelly – Malebranche y el libertinage érudit / Francisco Leocata – The problem of person and Jean Mouroux / John M. McDermott ; Glenn J. Comandini – Los fundamentos de la Bioética de H. Tristram Engelhardt / Jorge Martínez Barrera – Cuando las contradictorias son verdaderas / Marisa Villalba de Tablón – Examen del escepticismo moral y del relativismo moral / Camilo Tale – Saint Thomas et le mystère de la création : une réponse aux interrogations de l’homme daujourdhui / Marie-Dominique Philippe – La finalidad de la naturaleza humana : alcance y actualidad de la cuestión / Beatriz Eugenia Reyes Oribe – La providencia y el gobierno del mundo / Alberto Caturelli – Saint Thomas et le problème de la possibilité dun univers créé éternel / Alain-Marie de Lassus – La causalidad material de los elementos en la generación de los cuerpos mixtos / Mario Enrique Sacchi -- Bibliografía

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ESCEPTICISMO

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Contenido: Verdad, historia y hermenéutica / Octavio N. Derisi – El lumen naturale en Santo Tomás y el essere ideale en Rosmini / William R. Darós – El constitutivo esencial de la persona / Octavio N. Derisi – Filosofía y desarrollo integral / Alberto Caturelli – La respuesta del hombre frente a lo existente : intuición y palabra / Osvaldo Francella – Notas y comentarios -- Bibliografía

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Contenido: Il Dio dei filosofi e il Dio dei teologi in Guglielmo di Ockham / Alessandro Ghisalberti – La Trinidad divina y la deificación del hombre por el nacimiento del hijo en el alma, según los escritos del maestro Eckhart / Brian J. Farrelly – Suárez y Descartes sobre la noción de verdades eternas y su relación con Dios / Bernardo Cantens – Interacción mente-cuerpo y libre arbitrio en Descarles / Enrique Chávez-Arvizo – Razón y verdad : Hobbes y el Aquinate / María L. Lukac de Stier – Pascal y la crisis de la razón / Francisco Leocata – La contribución de Jacques Maritain a la teología natural / Juan J. Álvarez – Ontología de lo social / Abelardo Pithod – Réflexions sur une introduction à la métaphysique / Yves Floucat – El conocimiento divino del ente futuro contingente / Gabriel Delgado – Insegnamento sociale cristiano : magistero e scienze umane / Enrique Colom – Aquinas on Aristotle and creation : use or misuse? / Timothy L. Smith – La verdad, raíz de la libertad / Gustavo Eloy PonferradaBesoin de Dieu et dsir de Dieu : l’illusion dune mort / Michel Mahé – El ser a merced de la afectividad / Mario Enrique Sacchi – Notas y comentarios -- Bibliografía

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Contenido: Los caracteres del espíritu / Octavio N. Derisi – Significado y alcance de lo naturalmente conocido frente a la gnoseología contemporánea / Osvaldo Francella – Valores, realidad e irrealidad / Omar Argerami – Notas y comentarios -- Bibliografía

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Contenido: Actualidad de la doctrina tomista de los objetos formales / Octavio N. Derisi – Tomás de Aquino en la Universidad de París / Gustavo E. Ponferrada – La participación de la inteligencia en la experiencia sensible / Mario E. Sacchi – El pensamiento de Tomás de Aquino y los problemas de nuestro tiempo / Carmen Balzer – La existente y el campo específico de la metafísica / Osvaldo Francella –Notas y comentarios -- Bibliografía

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Contenido: L’inquiétude de Dieu chez saint Augustin / Rosa Muriel Zelasco – El camino trinitario a la deificación conforme a los místicos renanos del siglo XIV: Meister Eckhart, Juan Tauler y el beato Enrique Seuze / Brian J. Farrelly – El comentario de Santo Tomás a los Posteriores analíticos: notas metodológicas / Celina A. Lértora Mendoza – Memoria e identidad en Santo Tomás de Aquino / Martín Federico Echavarría -- ¿Elegimos a Dios?: acerca de la no elección del fin último en concreto según Tomás de Aquino / Beatriz Reyes Oribe – Hacia un realismo hermenéutico sobre la base Santo Tomás de Aquino-Husserl: Los horizontes / Gabriel J. Zanotti – Pascal à la lumière de saint Jean de la Croix / André Bord – El principio de contradicción en Kant / Lorenzo Vicente Burgoa – La mutua implicación poder-saber según Michel Foucault / Jorge Martínez Barrera – Modernidad e Ilustración en Jürgen Habermas / Francisco Leocata – Hacia una hermenéutica analógico-icónica del símbolo / Mauricio Beuchot – El principio de autoridad / Mario Enrique Sacchi – Notas y comentarios – Discusiones -- Bibliografía

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Contenido: Lo permanente y lo cambiante del conocimiento intelectivo / Octavio N. Derisi – Significado y alcance de lo naturalmente conocido frente a la gnoseología contemporánea (fin) / Osvaldo Francella – Instantaneidad del cambio substancial / J. E. Bolzán – Etapas en la evolución del pensamiento de Jean-Paul Sartre desde el punto de vista ético / Judith B. de González – Notas y comentarios – Bibliografía

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Resumen: El presente artículo, después de trazar un resumen del recorrido de los modos de historiar la filosofía, enfoca el tema de la relación entre ambos aspectos: el de la filosofía teorética y el de la historia de la filosofía. Toma distancia crítica tanto de la concepción que independiza la historia de la filosofía de la labor de bsqueda de la verdad teorética, como de la identificación de ambas dimensiones, tesis que tomó forma sobre todo a partir de Hegel. Propone una aplicación de la hermenéutica en la lectura del pasado filosófico, para abrir nuevas cuestiones y horizontes de bsqueda en el mundo de la realidad y en las exigencias y desafíos de la propia época histórica. Dicha hermenéutica, a su vez, no se desliza hacia el relativismo, sino que confirma la perennidad de lo verdadero en su persistencia fecunda a lo largo del tiempo.

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Contenido: Aspectos fundamentales del conocimiento humano. 1. El conocimiento sensitivo / Octavio N. Derisi -- Filosofía griega y cristianismo según W. Jaeger / Cesáreo López Salgado -- La analogía en el concepto de ciencia aristotélico-tomista / William R. Darós -- Pasión e instinto en B. Pascal / Francisco Leocata -- Notas y comentarios -- Bibliografía