2,115 research outputs found
Models of atypical development must also be models of normal development
Functional magnetic resonance imaging studies of developmental disorders and normal cognition that include children are becoming increasingly common and represent part of a newly expanding field of developmental cognitive neuroscience. These studies have illustrated the importance of the process of development in understanding brain mechanisms underlying cognition and including children ill the study of the etiology of developmental disorders
From perceptual to language-mediated categorization
From at least two months onwards, infants can form perceptual categories. During the first year of life, object knowledge develops from the ability to represent individual object features to representing correlations between attributes and to integrate information from different sources. At the end of the first year, these representations are shaped by labels, opening the way to conceptual knowledge. Here, we review the development of object knowledge and object categorization over the first year of life. We then present an artificial neural network model that models the transition from early perceptual categorization to categories mediated by labels. The model informs a current debate on the role of labels in object categorization by suggesting that although labels do not act as object features they nevertheless affect perceived similarity of perceptually distinct objects sharing the same label. The model presents the first step of an integrated account from early perceptual categorization to language-based concept learning
Biostratigraphy of the upper Bajocian-middle Callovian (Middle Jurassic), South America
The biostratigraphic division of the upper Bajocian-middle Callovian of South America is based on ammonites from different sections of the following provinces and regions: Neuquén, Mendoza, and San Juan in Argentina; Malleco, Linares, Talca, Atacama, Antofagasta, and Tarapacá in Chile. The complete upper Bajocian-middle Callovian succession includes the following biostratigraphic units: the Megasphaeroceras magnum assemblage zone, lowermost upper Bajocian; the Cadomites-Tulitidae mixed assemblage, (?lower) middle and upper Bathonian; the Steinmanni zone, index Lilloettia steinmanni (Spath), uppermost Bathonian, with two local horizons — Stehnocephalites gerthi horizon (Argentina) and Choffatia jupiter horizon (northern Chile); the Vergarensis zone, index Eur y cep halites vergarensis (Burck.), near the Bathonian-Callovian boundary; the Bodenbenderi zone, index Neuquenicerás (Frickites) bodenbenderi (Tornq.), lower Callovian; the Proximum zone, index Hecticoceras proximum Elmi, uppermost lower Callovian; and the Rehmannia (Loczyceras) patagoniensis horizon, middle Callovian.La división bioestratigráfica del Bajociano superior-Caloviano inferior de América del Sur esté basada en la fauna de amonites proveniente de diferentes secciones de las provincias/regiones de Neuquén, Mendoza, San Juan (Argentina), Malleco, Linares, Talca, Atacama, Antofagasta, y Tarapacá (Chile). La sucesión del Bajociano superior-Caloviano medio incluye las siguientes unidades bioestratigráfícas: zona de asociación de Megasphaeroceras magnum, Bajociano superior bajo; asociación de mezcla de Cadomites- Tulitidae, Bathoniano (?inferior) medio y superior; zona de Steinmanni, fósil guía Lilloettia steinmanni (Spath), Bathoniano superior alto, con dos horizontes locales — horizonte con Stehnocephalites gerthi (Argentina) y horizonte con Choffatia jupiter (norte de Chile); zona de Vergarensis, fósil guía Eurycephalites vergarensis (Burck.), aproximadamente límite Bathoniano-Caloviano; zona de Bodenbenderi, fósil guía Neuquenicerás (Frickites) bodenbenderi (Tornq.), Caloviano inferior; zona de Proximum, fósil guía Hecticoceras proximum Elmi, Caloviano inferior alto; horizonte con Rehmannia (Loczyceras) patagoniensis, Caloviano medio.Facultad de Ciencias Naturales y Muse
Biostratigraphy of the upper Bajocian-middle Callovian (Middle Jurassic), South America
The biostratigraphic division of the upper Bajocian-middle Callovian of South America is based on ammonites from different sections of the following provinces and regions: Neuquén, Mendoza, and San Juan in Argentina; Malleco, Linares, Talca, Atacama, Antofagasta, and Tarapacá in Chile. The complete upper Bajocian-middle Callovian succession includes the following biostratigraphic units: the Megasphaeroceras magnum assemblage zone, lowermost upper Bajocian; the Cadomites-Tulitidae mixed assemblage, (?lower) middle and upper Bathonian; the Steinmanni zone, index Lilloettia steinmanni (Spath), uppermost Bathonian, with two local horizons — Stehnocephalites gerthi horizon (Argentina) and Choffatia jupiter horizon (northern Chile); the Vergarensis zone, index Eur y cep halites vergarensis (Burck.), near the Bathonian-Callovian boundary; the Bodenbenderi zone, index Neuquenicerás (Frickites) bodenbenderi (Tornq.), lower Callovian; the Proximum zone, index Hecticoceras proximum Elmi, uppermost lower Callovian; and the Rehmannia (Loczyceras) patagoniensis horizon, middle Callovian.La división bioestratigráfica del Bajociano superior-Caloviano inferior de América del Sur esté basada en la fauna de amonites proveniente de diferentes secciones de las provincias/regiones de Neuquén, Mendoza, San Juan (Argentina), Malleco, Linares, Talca, Atacama, Antofagasta, y Tarapacá (Chile). La sucesión del Bajociano superior-Caloviano medio incluye las siguientes unidades bioestratigráfícas: zona de asociación de Megasphaeroceras magnum, Bajociano superior bajo; asociación de mezcla de Cadomites- Tulitidae, Bathoniano (?inferior) medio y superior; zona de Steinmanni, fósil guía Lilloettia steinmanni (Spath), Bathoniano superior alto, con dos horizontes locales — horizonte con Stehnocephalites gerthi (Argentina) y horizonte con Choffatia jupiter (norte de Chile); zona de Vergarensis, fósil guía Eurycephalites vergarensis (Burck.), aproximadamente límite Bathoniano-Caloviano; zona de Bodenbenderi, fósil guía Neuquenicerás (Frickites) bodenbenderi (Tornq.), Caloviano inferior; zona de Proximum, fósil guía Hecticoceras proximum Elmi, Caloviano inferior alto; horizonte con Rehmannia (Loczyceras) patagoniensis, Caloviano medio.Facultad de Ciencias Naturales y Muse
Biostratigraphy of the upper Bajocian-middle Callovian (Middle Jurassic), South America
The biostratigraphic division of the upper Bajocian-middle Callovian of South America is based on ammonites from different sections of the following provinces and regions: Neuquén, Mendoza, and San Juan in Argentina; Malleco, Linares, Talca, Atacama, Antofagasta, and Tarapacá in Chile. The complete upper Bajocian-middle Callovian succession includes the following biostratigraphic units: the Megasphaeroceras magnum assemblage zone, lowermost upper Bajocian; the Cadomites-Tulitidae mixed assemblage, (?lower) middle and upper Bathonian; the Steinmanni zone, index Lilloettia steinmanni (Spath), uppermost Bathonian, with two local horizons — Stehnocephalites gerthi horizon (Argentina) and Choffatia jupiter horizon (northern Chile); the Vergarensis zone, index Eur y cep halites vergarensis (Burck.), near the Bathonian-Callovian boundary; the Bodenbenderi zone, index Neuquenicerás (Frickites) bodenbenderi (Tornq.), lower Callovian; the Proximum zone, index Hecticoceras proximum Elmi, uppermost lower Callovian; and the Rehmannia (Loczyceras) patagoniensis horizon, middle Callovian.La división bioestratigráfica del Bajociano superior-Caloviano inferior de América del Sur esté basada en la fauna de amonites proveniente de diferentes secciones de las provincias/regiones de Neuquén, Mendoza, San Juan (Argentina), Malleco, Linares, Talca, Atacama, Antofagasta, y Tarapacá (Chile). La sucesión del Bajociano superior-Caloviano medio incluye las siguientes unidades bioestratigráfícas: zona de asociación de Megasphaeroceras magnum, Bajociano superior bajo; asociación de mezcla de Cadomites- Tulitidae, Bathoniano (?inferior) medio y superior; zona de Steinmanni, fósil guía Lilloettia steinmanni (Spath), Bathoniano superior alto, con dos horizontes locales — horizonte con Stehnocephalites gerthi (Argentina) y horizonte con Choffatia jupiter (norte de Chile); zona de Vergarensis, fósil guía Eurycephalites vergarensis (Burck.), aproximadamente límite Bathoniano-Caloviano; zona de Bodenbenderi, fósil guía Neuquenicerás (Frickites) bodenbenderi (Tornq.), Caloviano inferior; zona de Proximum, fósil guía Hecticoceras proximum Elmi, Caloviano inferior alto; horizonte con Rehmannia (Loczyceras) patagoniensis, Caloviano medio.Facultad de Ciencias Naturales y Muse
Growth and saturation of the Kelvin-Helmholtz instability with parallel and anti-parallel magnetic fields
We investigate the Kelvin-Helmholtz instability occuring at the interface of a shear flow configuration in 2D compressible magnetohydrodynamics (MHD). The linear growth and the subsequent non-linear saturation of the instability are studied numerically. We consider an initial magnetic field aligned with the shear flow, and analyze the differences between cases where the initial field is unidirectional everywhere (uniform case), and where the field changes sign at the interface (reversed case). We recover and extend known results for pure hydrodynamic and MHD cases with a discussion of the dependence of the non-linear saturation on the wavenumber, the sound Mach number, and the Alfvenic Mach number for the MHD case. A reversed field acts to destabilize the linear phase of the Kelvin-Helmholtz instability compared to the pure hydrodynamic case, while a uniform field suppresses its growth. In resistive MHD, reconnection events almost instantly accelerate the buildup of a global plasma circulation. They play an important role throughout the further non-linear evolution as well, since the initial current sheet gets amplified by the vortex flow and can become unstable to tearing instabilities forming magnetic islands. As a result, the saturation behaviour and the overall evolution of the density and the magnetic field is markedly different for the uniform versus the reversed field case
The Indo-Pacific ammonite <i>Mayaites</i> in the Oxfordian of the Southern Andes
Oxfordian Iitho- and biostratigraphy of the Chilean and Argentine Andes is reviewed (P. N. Stipanicic). Within the Chacay Group, the Lower to basal Upper Oxfordian La Manga Formation, below, mostly detrital and biogenic, and the Upper Oxfordian Auquilco Formation, above, mainly chemical, are distinguished. The La Manga Formation (with Gryphaea calceola lumachelle) is rich in ammonite faunas, particularly of thc upper Cordatum to lower Canaliculatum Zones. In Neuquén and Mendoza provinces of Argentina, the Plicatilis Zone or Middle Oxfordian has yielded Perísphinctes spp., Euaspidoceras spp., Aspidoceras spp., together with Mayaítes (Araucanites ) stípanícfcí, M. (A.) reyesi, and M. (A.) mulai, Westermann et Riccardi subgen. et spp. nov. The first find of Mayaitidae outside the Indo-Pacific province is discussed in light of _plate-tectonic theory.La revisión Iito- y bioestratigráfica del Oxfordiano de los Andes de Argentina y Chile (P. N. Stipanicic) ha permitido reconocer dentro del Grupo Chacay: 1) abajo, la Formación La Manga, mayormente detrítica y biogénica, del Oxfordiano inferior-superior basa!, y 2) arriba, la Formación Auquilco, mayormente química, del Oxfordiano superior. La Formación La Manga (con lumachelas de Gryphaea calceola) contiene abundante cantidad de amonitas, particularmente de las Zonas de Cordatum superior a Canaliculatum inferior. En las provincias de Mendoza y Neuquén, Argentina, la Zona de Plicatilis (Oxfordiano medio) contiene Perispbinctes spp., Euaspidoceras spp., Aspidoceras spp., conjuntamente con Mayaites (Araucanites) stipanicici, M. (A.) reyesi, y M. (A.) mulai, Westermann et Riccardi subgen. et spp. nov. El primer hallazgo de Mayaitidae fuera de la provincia lndo-Pacífica es discutido tomando en consideración la teoría de tectónica de placas.Universidad Nacional de La Plata (UNLP) - Facultad de Ciencias Naturales y Museo (FCNM
The Indo-Pacific ammonite <i>Mayaites</i> in the Oxfordian of the Southern Andes
Oxfordian Iitho- and biostratigraphy of the Chilean and Argentine Andes is reviewed (P. N. Stipanicic). Within the Chacay Group, the Lower to basal Upper Oxfordian La Manga Formation, below, mostly detrital and biogenic, and the Upper Oxfordian Auquilco Formation, above, mainly chemical, are distinguished. The La Manga Formation (with Gryphaea calceola lumachelle) is rich in ammonite faunas, particularly of thc upper Cordatum to lower Canaliculatum Zones. In Neuquén and Mendoza provinces of Argentina, the Plicatilis Zone or Middle Oxfordian has yielded Perísphinctes spp., Euaspidoceras spp., Aspidoceras spp., together with Mayaítes (Araucanites ) stípanícfcí, M. (A.) reyesi, and M. (A.) mulai, Westermann et Riccardi subgen. et spp. nov. The first find of Mayaitidae outside the Indo-Pacific province is discussed in light of _plate-tectonic theory.La revisión Iito- y bioestratigráfica del Oxfordiano de los Andes de Argentina y Chile (P. N. Stipanicic) ha permitido reconocer dentro del Grupo Chacay: 1) abajo, la Formación La Manga, mayormente detrítica y biogénica, del Oxfordiano inferior-superior basa!, y 2) arriba, la Formación Auquilco, mayormente química, del Oxfordiano superior. La Formación La Manga (con lumachelas de Gryphaea calceola) contiene abundante cantidad de amonitas, particularmente de las Zonas de Cordatum superior a Canaliculatum inferior. En las provincias de Mendoza y Neuquén, Argentina, la Zona de Plicatilis (Oxfordiano medio) contiene Perispbinctes spp., Euaspidoceras spp., Aspidoceras spp., conjuntamente con Mayaites (Araucanites) stipanicici, M. (A.) reyesi, y M. (A.) mulai, Westermann et Riccardi subgen. et spp. nov. El primer hallazgo de Mayaitidae fuera de la provincia lndo-Pacífica es discutido tomando en consideración la teoría de tectónica de placas.Universidad Nacional de La Plata (UNLP) - Facultad de Ciencias Naturales y Museo (FCNM
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Tumor necrosis factor-alpha regulates the expression of inducible costimulator receptor ligand on CD34+ progenitor cells during differentiation into antigen presenting cells
The inducible costimulator receptor (ICOS) is a third member of the CD28 receptor family that regulates T cell activation and function. ICOS binds to a newly identified ligand on antigen presenting cells different from the CD152 ligands CD80 and CD86. We used soluble ICOSIg and a newly developed murine anti-human ICOS ligand (ICOSL) monoclonal antibody to further characterize the ICOSL during ontogeny of antigen presenting cells. In a previous study, we found that ICOSL is expressed on monocytes, dendritic cells, and B cells. To define when ICOSL is first expressed on myeloid antigen presenting cells, we examined ICOSL expression on CD34 cells in bone marrow. We found that CD34bright cells regardless of their myeloid commitment were ICOSL , whereas ICOSL was first expressed when CD34 expression diminished and the myeloid marker CD33 appeared
The Geoff Egan Memorial Lecture 2011. Artefacts, art and artifice: reconsidering iconographic sources for archaeological objects in early modern Europe
A first systematic analysis of historic domestic material culture depicted in contemporaneous Western painting and prints, c.1400-1800. Drawing on an extensive data set, the paper proposes to methodologies and hermeneutics for historical analysis and archaeological correspondence
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