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Individual Objects (individual + object)
Selected AbstractsCorrelated attributes and categorization in the first half-year of lifeDEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2004Ramesh S. Bhatt Abstract In two experiments with 36 human infants, we asked whether 3- and 6-month-olds could use correlations between attributes of individual objects to categorize. Infants learned to kick to move block mobiles that simultaneously displayed two categories defined by the figures displayed on them: the colors of the figures and the colors of the blocks. Two features were correlated, and the third varied across categories. Only 6-month-olds categorized novel category exemplars that preserved the original feature correlations (Experiment 1A), but both 3- and 6-month-olds discriminated feature recombinations that broke the original correlations (Experiment 1B). When category exemplars were presented successively, 6-month-olds also learned the feature correlations and used them to categorize (Experiment 2), but their performance was less robust. Infants' superior learning when stimuli were presented simultaneously may reflect "unitization," a learning disposition unique to immature infants. These experiments reveal that infants' ability to use correlated attributes to categorize emerges months earlier than previously thought. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 103,115, 2004. [source] Individuation of pairs of objects in infancyDEVELOPMENTAL SCIENCE, Issue 4 2007Alan M. Leslie Looking-time studies examined whether 11-month-old infants can individuate two pairs of objects using only shape information. In order to test individuation, the object pairs were presented sequentially. Infants were familiarized either with the sequential pairs, disk-triangle/disk-triangle (XY/XY), whose shapes differed within but not across pairs, or with the sequential pairs, disk-disk/triangle-triangle (XX/YY), whose shapes differed across but not within pairs. The XY/XY presentation looked to adults like a single pair of objects presented repeatedly, whereas the XX/YY presentation looked like different pairs of objects. Following familiarization to these displays, infants were given a series of test trials in which the screen was removed, revealing two pairs of objects in one of two outcomes, XYXY or XXYY. On the first test trial, infants familiarized with the identical pairs (XY/XY) apparently expected a single pair to be revealed because they looked longer than infants familiarized with the distinct pairs (XX/YY). Infants who had seen the distinct pairs apparently expected a double pair outcome. A second experiment showed outcomes of a single XY pair. This outcome is unexpected for XX/YY-familiarized infants but expected for XY/XY-familiarized infants, the reverse of Experiment 1. This time looking times were longer for XX/YY infants. Eleven-month-olds appear to be able to represent not just individual objects but also pairs of objects. These results suggest that if they can group the objects into sets, infants may be able to track more objects than their numerosity limit or available working memory slots would normally allow. We suggest possible small exact numerosity representations that would allow tracking of such sets. [source] Entorhinal cortex contributes to object-in-place scene memoryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2004David P. Charles Abstract Four rhesus monkeys (Macaca mulatta) were trained preoperatively in a test of object-in-place scene memory. They were presented daily with lists of unique computer-generated scenes each containing a spatial array of multiple individual objects. Within each scene, objects to be discriminated appeared in the foreground, each occupying a unique location, and monkeys were required to correctly discriminate the rewarded object to receive a food reward. Once this preoperative criterion was attained, the monkeys received bilateral entorhinal cortex ablation performed as either one or two surgical operations with a period of testing following each. Postoperatively, they were significantly impaired in learning new object-in-place scene problems. These results show that the entorhinal cortex, like anatomically related structures including the perirhinal cortex and the fornix, contributes to object-in-place scene learning. [source] Classification of protein crystallization images using Fourier descriptorsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3 2007James Foadi The two-dimensional Fourier transform (2D-FT) is well suited to the extraction of features to differentiate image texture, and the classification of images based on information acquired from the frequency domain provides a complementary method to approaches based within the spatial domain. The intensity, I, of the Fourier-transformed images can be modelled by an equation of power law form, I = Ar,, where A and , are constants and r is the radial spatial frequency. The power law is fitted over annuli, centred at zero spatial frequency, and the parameters, A and ,, determined for each spatial frequency range. The variation of the fitted parameters across wedges of fixed polar angle provides a measure of directionality and the deviation from the fitted model can be exploited for classification. The classification results are combined with an existing method to classify individual objects within the crystallization drop to obtain an improved overall classification rate. [source] Cover Picture: J. Biophoton.JOURNAL OF BIOPHOTONICS, Issue 7 20107/2010 Video rate STED Nanoscopy visualizes the motion of neurotransmitter vesicles in living neurons. A STED highresolution movie (front filmstrip) resolves individual objects in the axons. In contrast, a confocal movie (back filmstrip) shows only unspecific motion. (Picture: M. A. Lauterbach et al., see also pp. 417,424 in this issue) The authors thank Hartmut Sebesse (Printing and Graphics Office of the Max Planck Institute for Biophysical Chemistry) for his skillful help in preparing the cover picture (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Proper Names in Early Word Learning: Rethinking a Theoretical Account of Lexical DevelopmentMIND & LANGUAGE, Issue 4 2009D. GEOFFREY HALL There is evidence that children learn both proper names and count nouns from the outset of lexical development. Furthermore, children's first proper names are typically words for people, whereas their first count nouns are commonly terms for other objects, including artifacts. I argue that these facts represent a challenge for two well-known theoretical accounts of object word learning. I defend an alternative account, which credits young children with conceptual resources to acquire words for both individual objects and object categories, and conceptual biases to construe some objects (notably people) as individuals in their own right and most other objects as instances of their category. [source] Approximation algorithms for channel allocation problems in broadcast networksNETWORKS: AN INTERNATIONAL JOURNAL, Issue 4 2006Rajiv Gandhi Abstract We study two packing problems that arise in the area of dissemination-based information systems; a second theme is the study of distributed approximation algorithms. The problems considered have the property that the space occupied by a collection of objects together could be significantly less than the sum of the sizes of the individual objects. In the Channel Allocation Problem, there are requests that are subsets of topics. There are a fixed number of channels that can carry an arbitrary number of topics. All the topics of each request must be broadcast on some channel. The load on any channel is the number of topics that are broadcast on that channel; the objective is to minimize the maximum load on any channel. We present approximation algorithms for this problem, and also show that the problem is MAX-SNP hard. The second problem is the Edge Partitioning Problem addressed by Goldschmidt, Hochbaum, Levin, and Olinick (Networks, 41:13,23, 2003). Each channel here can deliver topics for at most k requests, and we aim to minimize the total load on all channels. We present an O(n1/3),approximation algorithm, and also show that the algorithm can be made fully distributed with the same approximation guarantee; we also generalize the (nondistributed) Edge Partitioning Problem of graphs to the case of hypergraphs. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 47(4), 225,236 2006 [source] Scientific Structuralism: On the Identity and Diversity of Objects in a StructureARISTOTELIAN SOCIETY SUPPLEMENTARY VOLUME, Issue 1 2007James Ladyman The identity and diversity of individual objects may be grounded or ungrounded, and intrinsic or contextual. Intrinsic individuation can be grounded in haecceities, or absolute discernibility. Contextual individuation can be grounded in relations, but this is compatible with absolute, relative or weak discernibility. Contextual individuation is compatible with the denial of haecceitism, and this is more harmonious with science. Structuralism implies contextual individuation. In mathematics contextual individuation is in general primitive. In physics contextual individuation may be grounded in relations via weak discernibility. [source] Accreting white dwarfs as supersoft X-ray sourcesASTRONOMISCHE NACHRICHTEN, Issue 2 2010M. Kato Abstract I review various phenomena associated with mass-accreting white dwarfs (WDs) in the view of supersoft X-ray sources. When the mass-accretion rate is low (,acc < a few × 10,7 M,yr,1), hydrogen nuclear burning is unstable and nova outbursts occur. A nova is a transient supersoft X-ray source (SSS) in its later phase which timescale depends strongly on the WD mass. The X-ray turn on/off time is a good indicator of the WD mass. At an intermediate mass-accretion rate an accreting WD becomes a persistent SSS with steady hydrogen burning. For a higher mass-accretion rate, the WD undergoes "accretion wind evolution" in which the WD accretes matter from the equatorial plane and loses mass by optically thick winds from the other directions. Two SSS, namely RX J0513-6951 and V Sge, are corresponding objects to this accretion wind evolution. We can specify mass increasing WDs from light-curve analysis based on the optically thick wind theory using multiwavelength observational data including optical, IR, and supersoft X-rays. Mass estimates of individual objects give important information for the binary evolution scenario of type Ia supernovae (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Evolution of radio galaxiesASTRONOMISCHE NACHRICHTEN, Issue 2-3 2009C.R. Kaiser Abstract The dynamical evolution of FRII-type radio galaxies can be successfully modelled employing purely analytical techniques. The solutions change depending on the lobe size relative to the characteristic length scale for individual objects, resulting in three distinct regimes. By far the best understood regime is that of large sources. For these we can also construct emission models predicting the evolution of the radio luminosity as a function of source size or age and a limited number of source parameters. We can use such models to constrain the evolution of the radio galaxy population as a whole. Building on these successes, we find some hints that radio galaxies can change their morphologies between the two FR classes. Better emission models for all length scales and models for FRI-type objects are now needed to progress our understanding of all evolutionary branches of radio galaxies (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Nearby stars of the Galactic disk and halo.ASTRONOMISCHE NACHRICHTEN, Issue 1 2004Abstract High-resolution spectroscopic observations of about 150 nearby stars or star systems are presented and discussed. The study of these and another 100 objects of the previous papers of this series implies that the Galaxy became reality 13 or 14 Gyr ago with the implementation of a massive, rotationally-supported population of thick-disk stars. The very high star formation rate in that phase gave rise to a rapid metal enrichment and an expulsion of gas in supernovae-driven Galactic winds, but was followed by a star formation gap for no less than three billion years at the Sun's galactocentric distance. In a second phase, then, the thin disk , our "familiar Milky Way" , came on stage. Nowadays it traces the bright side of the Galaxy, but it is also embedded in a huge coffin of dead thick-disk stars that account for a large amount of baryonic dark matter. As opposed to this, cold-dark-matter-dominated cosmologies that suggest a more gradual hierarchical buildup through mergers of minor structures, though popular, are a poor description for the Milky Way Galaxy , and by inference many other spirals as well , if, as the sample implies, the fossil records of its long-lived stars do not stick to this paradigm. Apart from this general picture that emerges with reference to the entire sample stars, a good deal of the present work is however also concerned with detailed discussions of many individual objects. Among the most interesting we mention the blue straggler or merger candidates HD 165401 and HD 137763/HD 137778, the likely accretion of a giant planet or brown dwarf on 59 Vir in its recent history, and HD 63433 that proves to be a young solar analog at , , 200 Myr. Likewise, the secondary to HR 4867, formerly suspected non-single from the Hipparcos astrometry, is directly detectable in the highresolution spectroscopic tracings, whereas the visual binary , Cet is instead at least triple, and presumably even quadruple. With respect to the nearby young stars a complete account of the UrsaMajor Association is presented, and we provide as well plain evidence for another, the "Hercules-Lyra Association", the likely existence of which was only realized in recent years. On account of its rotation, chemistry, and age we do confirm that the Sun is very typical among its G-type neighbors; as to its kinematics, it appears however not unlikely that the Sun's known low peculiar space velocity could indeed be the cause for the weak paleontological record of mass extinctions and major impact events on our parent planet during the most recent Galactic plane passage of the solar system. Although the significance of this correlation certainly remains a matter of debate for years to come, we point in this context to the principal importance of the thick disk for a complete census with respect to the local surface and volume densities. Other important effects that can be ascribed to this dark stellar population comprise (i) the observed plateau in the shape of the luminosity function of the local FGK stars, (ii) a small though systematic effect on the basic solar motion, (iii) a reassessment of the term "asymmetrical drift velocity" for the remainder (i.e. the thin disk) of the stellar objects, (iv) its ability to account for the bulk of the recently discovered high-velocity blue white dwarfs, (v) its major contribution to the Sun's ,220 km s,1 rotational velocity around the Galactic center, and (vi) the significant flattening that it imposes on the Milky Way's rotation curve. Finally we note a high multiplicity fraction in the small but volume-complete local sample of stars of this ancient population. This in turn is highly suggestive for a star formation scenario wherein the few existing single stellar objects might only arise from either late mergers or the dynamical ejection of former triple or higher level star systems. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||