3,272 research outputs found
In vivo cranial bone strain and bite force in the agamid lizard Uromastyx geyri
In vivo bone strain data are the most direct evidence of deformation and strain regimes in the vertebrate cranium during feeding and can provide important insights into skull morphology. Strain data have been collected during feeding across a wide range of mammals; in contrast, in vivo cranial bone strain data have been collected from few sauropsid taxa. Here we present bone strain data recorded from the jugal of the herbivorous agamid lizard Uromastyx geyri along with simultaneously recorded bite force. Principal and shear strain magnitudes in Uromastyx geyri were lower than cranial bone strains recorded in Alligator mississippiensis, but higher than those reported from herbivorous mammals. Our results suggest that variations in principal strain orientations in the facial skeleton are largely due to differences in feeding behavior and bite location, whereas food type has little impact on strain orientations. Furthermore, mean principal strain orientations differ between male and female Uromastyx during feeding, potentially because of sexual dimorphism in skull morphology
Trajectory generation for road vehicle obstacle avoidance using convex optimization
This paper presents a method for trajectory generation using convex optimization to find a feasible, obstacle-free path for a road vehicle. Consideration of vehicle rotation is shown to be necessary if the trajectory is to avoid obstacles specified in a fixed Earth axis system. The paper establishes that, despite the presence of significant non-linearities, it is possible to articulate the obstacle avoidance problem in a tractable convex form using multiple optimization passes. Finally, it is shown by simulation that an optimal trajectory that accounts for the vehicle’s changing velocity throughout the manoeuvre is superior to a previous analytical method that assumes constant speed
Biomedical image sequence analysis with application to automatic quantitative assessment of facial paralysis
Facial paralysis is a condition causing decreased movement on one side of the face. A quantitative, objective, and reliable assessment system would be an invaluable tool for clinicians treating patients with this condition. This paper presents an approach based on the automatic analysis of patient video data. Facial feature localization and facial movement detection methods are discussed. An algorithm is presented to process the optical flow data to obtain the motion features in the relevant facial regions. Three classification methods are applied to provide quantitative evaluations of regional facial nerve function and the overall facial nerve function based on the House-Brackmann scale. Experiments show the radial basis function (RBF) neural network to have superior performance
Biomedical image sequence analysis with application to automatic quantitative assessment of facial paralysis
Facial paralysis is a condition causing decreased movement on one side of the face. A quantitative, objective, and reliable assessment system would be an invaluable tool for clinicians treating patients with this condition. This paper presents an approach based on the automatic analysis of patient video data. Facial feature localization and facial movement detection methods are discussed. An algorithm is presented to process the optical flow data to obtain the motion features in the relevant facial regions. Three classification methods are applied to provide quantitative evaluations of regional facial nerve function and the overall facial nerve function based on the House-Brackmann scale. Experiments show the radial basis function (RBF) neural network to have superior performance
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Receptive Field Characteristics That Allow Parietal Lobe Neurons to Encode Spatial Properties of Visual Input: A Computational Analysis
A subset of visually sensitive neurons in the parietal lobe apparently can encode the locations of stimuli, whereas visually sensitive neurons in the inferotemporal cortex (area IT) cannot. This finding is puzzling because both sorts of neurons have large receptive fields, and yet location can be encoded in one case, but not in the other. The experiments reported here investigated the hypothesis that a crucial difference between the IT and parietal neurons is the spatial distribution of their response profiles. In particular, IT neurons typically respond maximally when stimuli are presented at the fovea, whereas parietal neurons do not. We found that a parallel-distributed-processing network could map a point in an array to a coordinate representation more easily when a greater proportion of its input units had response peaks off the center of the input array. Furthermore, this result did not depend on potentially implausible assumptions about the regularity of the overlap in receptive fields or the homogeneity of the response profiles of different units. Finally, the internal representations formed within the network had receptive fields resembling those found in area 7a of the parietal lobe.Psycholog
Revista de Indias y Anuario de Estudios Americanos. Visibilidad y uso de la ediciĂłn electrĂłnica
Una dĂ©cada americanista en lĂnea, 2010, [En lĂnea], Puesto en lĂnea el 25 mayo 2010[EN] In this article we analyze the online visibility and content usage of two Americanist Journals published by CSIC, Revista de Indias and Anuario de Estudios Americanos. The online edition dates back to 2007; contents are comparable in terms of accessible documents, and both Journals are published in Open Access, with a 6-months embargo. We also discuss some methodological issues in terms of the need of a data normalization allowing the measurement of genuine downloads assimilable to document reading. Both Journals registered close to 500,000 normalized downloads along 2008 and 2009, most coming from Latin America and the United States (70%). Data show a high degree of repeated downloads of the same document from the same user (25% of total downloads) and indexation downloads (25% of normalized downloads), and also the lack of correlation between Journal’s visibility (webpage visits) and content usage (document downloads). Access restriction has a negative effect, as evidenced by the low downloading of embargoed documents[ES] En este artĂculo analizamos los datos de visibilidad y uso de las dos revistas de temática americanista editadas por el CSIC, Revista de Indias y Anuario de Estudios Americanos. La ediciĂłn electrĂłnica de ambas data de 2007, y su contenido en artĂculos accesibles es comparable; ambas se publican en Acceso Abierto (OA) con un embargo de acceso de 6 meses. TambiĂ©n analizamos cuestiones metodolĂłgicas relativas al análisis de descargas, en el sentido de la necesidad de una normalizaciĂłn de los datos que permita determinar las descargas reales, asimilables a una lectura del documento. Durante los años 2008 y 2009, ambas revistas han recibido cerca de 500.000 descargas normalizadas, que provienen en su mayorĂa de LatinoamĂ©rica y Estados Unidos (70%). Los datos muestran el elevado nĂşmero de descargas repetidas de documentos en periodos cortos de tiempo por el mismo usuario (25% de las totales registradas) y de descargas de indizaciĂłn (25% de las descargas normalizadas), y tambiĂ©n la falta de correlaciĂłn entre visibilidad de las revistas (visitas a páginas web) y uso de los contenidos (descarga de documentos). La restricciĂłn de acceso tiene un efecto perjudicial, evidenciado por el bajo nivel de descarga de los documentos sometidos a embargoPeer reviewe
Conceptual learning : the priority for higher education
The common sense notion of learning as the all-pervasive acquisition of new behaviour and knowledge, made vivid by experience, is an incomplete characterisation, because it assumes that the learning of behaviour and the learning of knowledge are indistinguishable, and that acquisition constitutes learning without reference to transfer. A psychological level of analysis is used to argue that conceptual learning should have priority in higher education
Competing anisotropies in exchange biased nano-structured thin films
The magnetic anisotropies of a patterned, exchange biased Fe50 Mn50 /Ni80 Fe20 system are studied using ferromagnetic resonance, supplemented by Brillouin light scattering experiments and Kerr magnetometry. The exchange biased bilayer is partially etched into an antidot geometry so that the system approximates a Ni80 Fe20 layer in contact with antidot structured Fe50 Mn50 . Brillouin light scattering measurements of the spin wave frequency dependence on the wave vector reveal a magnonic band gap as expected for a periodic modulation of the
magnetic properties. Analysis of the ferromagnetic resonance spectra reveals eightfold and fourfold contributions to the magnetic anisotropy. Additionally, the antidot patterning decreases the magnitude of the exchange bias and modifies strongly its angular dependence. Softening of all resonance modes is most pronounced for the applied magnetic field aligned within 10â—¦ of the antidot axis, in the direction of the bias. Given the degree to which one can tailor the ground state, the resulting asymmetry at low frequencies could make this an interesting candidate for applications such as selective/directional microwave filtering and multistate magnetic logic
Prolonged magmatism and growth of the Iran-Anatolia Cadomian continental arc segment in Northern Gondwana
Much of the crust of Iran and Anatolia, including their oldest exposed rocks, formed during an episode of intense convergent margin (arc) magmatism as a result of subduction of oceanic lithosphere beneath northern Gondwana from ca 620 Ma to ca 500 Ma, the Cadomian crust-forming event. Most igneous rocks formed between ca 570 and 525 Ma. Cadomian crust is well-known from western and southern Europe and from eastern North America but is much less well-known from Iran and Anatolia. We use published age and compositional data and contribute new data in order to better understand this ancient magmatic system. Cadomian magmatism included calc-alkaline igneous rocks of arc affinity in the main arc and alkalic igneous rocks that formed in a back-arc setting; these igneous rocks are associated with sedimentary rocks. Geochemical and isotopic modelling reveals that basaltic magmas were the main input, that these formed by partial melting in the upper mantle, and that basaltic magmas evolved further in deep crustal hot zones to form granitic magmas through a combination of assimilating older continental crust and fractional crystalization of basaltic magmas.This study was funded by the “ National Key Research and Development Program of China ( 2016YFE0203000 )” and by “ Chinese Academy of Sciences , President's International Fellowship Initiative (PIFI, 2019VCB0013 ). Financial support was also received from the Alexander von Humboldt Foundation in the form of a senior research grant and GEOMAR Helmholtz Centre while preparing these results for publication. FL gratefully acknowledges the PRIN2017 Project 20177BX42Z_001 (Intraplate deformation, magmatism and topographic evolution of a diffuse collisional belt: Insights into the geodynamics of the Arabia-Eurasia collisional zones) and the grant to Department of Science, Roma Tre University (MIUR-Italy Dipartimenti di Eccellenza, ARTICOLO 1, COMMI 314 – 337 LEGGE 232/2016 ). We thank Semih Gürsu for providing us bulk rock data from Derik complex of Turkey. Zircon U–Pb geochronology and and Lu–Hf isotope data were obtained using instrumentation funded by DEST Systemic Infrastructure Grants, ARC LIEF, NCRIS/AuScope, industry partners, and Macquarie University. All logistical support for field studies came from Damghan University. This is contribution 1544 from the ARC Centre of Excellence for Core to Crust Fluid Systems ( http://www.ccfs.mq.edu.au ) and 1412 in the GEMOC Key Centre ( http://www.gemoc.mq.edu.au ), and 1380 from UTD Geosciences and is related to IGCP-662. from the ARC Centre of Excellence for Core to Crust Fluid Systems ( http://www.ccfs.mq.edu.au ), xxxx from the GEMOC Key Centre ( http://www.gemoc.mq.edu.au ), and xxxx from UTD Geosciences and is related to IGCP-662
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