383 research outputs found

    Efficient Hessian computation using sparse matrix derivatives in RAM notation

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    Within-person structures of daily cognitive performance cannot be inferred from between-person structures of cognitive abilities

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    First published online: 09 June 2020Over a century of research on between-person differences has resulted in the consensus that human cognitive abilities are hierarchically organized, with a general factor, termed general intelligence or "g," uppermost. Surprisingly, it is unknown whether this body of evidence is informative about how cognition is structured within individuals. Using data from 101 young adults performing nine cognitive tasks on 100 occasions distributed over six months, we find that the structures of individuals' cognitive abilities vary among each other, and deviate greatly from the modal between-person structure. Working memory contributes the largest share of common variance to both between- and within-person structures, but the g factor is much less prominent within than between persons. We conclude that between-person structures of cognitive abilities cannot serve as a surrogate for within-person structures. To reveal the development and organization of human intelligence, individuals need to be studied over time

    Search for three alpha states around an 16^{16}O core in 28^{28}Si

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    We investigate the existence of weakly coupled gas-like states comprised of three α\alpha particles around an 16^{16}O core in 28^{28}Si. We calculate the excited states in 28^{28}Si using the multi-configuration mixing method based on the 16^{16}O + 3α\alpha cluster model. We also include the 16^{16}O + 12^{12}C and 24^{24}Mg + α\alpha basis wave functions prepared by the generator coordinate method. To identify the gas-like states, we calculate the isoscalar monopole transition strengths and the overlap of the obtained states with the geometrical cluster wave function and the Tohsaki-Horiuchi-Schuck-R\"{o}pke (THSR) wave function. The results show that the obtained fourth and twelfth states significantly overlap with the THSR wave function. These two states clearly coexist with the 16^{16}O + 12^{12}C cluster states, emerging at similar energies. The calculated isoscalar monopole strengths between those two states are significantly large, indicating that the states are members of the excitation mode. Furthermore, the calculated root-mean-squared (RMS) radii for these states also suggest that a layer of gas-like three α\alpha particles could exist around the surface of the 16^{16}O core, which can be described as a "two-dimensional gas" in the intermediate state before the Hoyle-like three α\alpha states emerge.Comment: 5 pages, 3 figure

    Alpha-cluster Condensations in Nuclei and Experimental Approaches for their Studies

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    The formation of alpha-clusters in nuclei close to the decay thresholds is discussed. These states can be considered to be boson-condensates, which are formed in a second order phase transition in a mixture of nucleons and alpha-particles. The de Broglie wavelength of the alpha-particles is larger than the nuclear diameter, therefore the coherent properties of the alpha-particles give particular effects for the study of such states. The states are above the thresholds thus the enhanced emission of multiple-alphas into the same direction is observed. The probability for the emission of multiple-alphas is not described by Hauser-Feshbach theory for compound nucleus decay.Comment: 21 pages, 12 figures

    Déjà vu and the entorhinal cortex: dissociating recollective from familiarity disruptions in a single case patient

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    Past research has demonstrated a relationship between déjà vu and the entorhinal cortex in patients with wider medial temporal lobe damage. The aim of the present research was to investigate this crucial link in a patient (MR) with a selective lesion to the left lateral entorhinal cortex to provide a more direct exploration of this relationship. Two experiments investigated the experiences of déjà vécu (using the IDEA questionnaire) and déjà vu (using an adapted DRM paradigm) in MR and a set of matched controls. The results demonstrated that MR had quantitatively more and qualitatively richer recollective experiences of déjà vécu. In addition, under laboratory-based déjà vu conditions designed to elicit both false recollection (critical lures) and false familiarity (weakly-associated lures), MR only revealed greater memory impairments for the latter. The present results are therefore the first to demonstrate a direct relationship between the entorhinal cortex and the experience of both déjà vu and déjà vécu. They furthermore suggest that the entorhinal cortex is involved in both weakly-associative false memory as well as strongly-associative memory under conditions that promote familiarity-based processing

    A group comparison test under uncertain group membership

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    Di-neutron elastic transfer in the 4He(6He,6He)4He reaction

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    Elastic 6^{6}He+4^4He data measured at Ec.m.=11.6,E_{\rm c.m.}=11.6, 15.9, and 60.3 MeV have been analyzed within the coupled reaction channels (CRC) formalism, with the elastic-scattering and two-neutron (2n2n) transfer amplitudes coherently included. Contributions from the direct (one-step) and sequential (two-step) 2n2n-transfers were treated explicitly based on a realistic assumption for the 2n2n-transfer form factor. The oscillatory pattern observed in 4^4He(6^6He,6^6He)4^4He angular distribution at low energies was found to be due to an interference between the elastic scattering and 2n2n-transfer amplitudes. Our CRC analysis shows consistently that the direct 2n2n-transfer strongly dominates over the sequential transfer and thus confirms the dominance of 2n4n-^4He configuration over the n5n-^5He one in the 6^6He wave function. This result suggests a strong clusterization of the two valence neutrons and allows, therefore, a reliable estimate for the \emph{di-neutron} spectroscopic amplitude.Comment: Accepted for publication in Phys. Lett.

    16O+16O^{16}{\rm O} + ^{16}{\rm O} nature of the superdeformed band of 32S^{32}{\rm S} and the evolution of the molecular structure

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    The relation between the superdeformed band of 32S^{32}{\rm S} and 16O+16O^{16}{\rm O} + ^{16}{\rm O} molecular bands is studied by the deformed-base antisymmetrized molecular dynamics with the Gogny D1S force. It is found that the obtained superdeformed band members of 32S^{32}{\rm S} have considerable amount of the 16O+16O^{16}{\rm O} + ^{16}{\rm O} component. Above the superdeformed band, we have obtained two excited rotational bands which have more prominent character of the 16O+16O^{16}{\rm O} + ^{16}{\rm O} molecular band. These three rotational bands are regarded as a series of 16O+16O^{16}{\rm O} + ^{16}{\rm O} molecular bands which were predicted by using the unique 16O^{16}{\rm O} -16O^{16}{\rm O} optical potentil. As the excitation energy and principal quantum number of the relative motion increase, the 16O+16O^{16}{\rm O} + ^{16}{\rm O} cluster structure becomes more prominent but at the same time, the band members are fragmented into several states
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