1,848 research outputs found

    The Compositional Nature of Verb and Argument Representations in the Human Brain

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    How does the human brain represent simple compositions of objects, actors,and actions? We had subjects view action sequence videos during neuroimaging (fMRI) sessions and identified lexical descriptions of those videos by decoding (SVM) the brain representations based only on their fMRI activation patterns. As a precursor to this result, we had demonstrated that we could reliably and with high probability decode action labels corresponding to one of six action videos (dig, walk, etc.), again while subjects viewed the action sequence during scanning (fMRI). This result was replicated at two different brain imaging sites with common protocols but different subjects, showing common brain areas, including areas known for episodic memory (PHG, MTL, high level visual pathways, etc.,i.e. the 'what' and 'where' systems, and TPJ, i.e. 'theory of mind'). Given these results, we were also able to successfully show a key aspect of language compositionality based on simultaneous decoding of object class and actor identity. Finally, combining these novel steps in 'brain reading' allowed us to accurately estimate brain representations supporting compositional decoding of a complex event composed of an actor, a verb, a direction, and an object.Comment: 11 pages, 6 figure

    The Compositional Nature of Event Representations in the Human Brain

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    How does the human brain represent simple compositions of constituents: actors, verbs, objects, directions, and locations? Subjects viewed videos during neuroimaging (fMRI) sessions from which sentential descriptions of those videos were identified by decoding the brain representations based only on their fMRI activation patterns. Constituents (e.g., fold and shirt) were independently decoded from a single presentation. Independent constituent classification was then compared to joint classification of aggregate concepts (e.g., fold-shirt); results were similar as measured by accuracy and correlation. The brain regions used for independent constituent classification are largely disjoint and largely cover those used for joint classification. This allows recovery of sentential descriptions of stimulus videos by composing the results of the independent constituent classifiers. Furthermore, classifiers trained on the words one set of subjects think of when watching a video can recognise sentences a different subject thinks of when watching a different video

    Assessment of viral and non-viral gene transfer into adult rat brains using HSV-1, calcium phosphate and PEI-based methods

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    CNS gene transfer could provide new approaches to the modelling of neurodegenerative diseases and devising potential therapies. One such disorder is Parkinson’s disease (PD), in which dysfunction of several different metabolic processes has been implicated. Here we review the literature on gene transfer systems based on herpes simplex virus type 1 (HSV-1) and non-viral polyethyleneimine (PEI) and calcium phosphate nanoparticle methods. We also assess the usefulness of various CNS gene delivery methods and present some of our own data to exemplify such usefulness. Our data result from vectors stereotaxically introduced to the substantia nigra (SN) of adult rats and evaluated 1 week and/or 1 month post injection using histochemical methods to assess recombinant ß-galactosidase enzyme activity. Gene transfer using PEI or calcium phosphate-mediated transfections was observed for both methods and PEI was comparable to that of HSV-1 amplicon. Our data show that the amplicon delivery was markedly increased when packaged with a helper virus and was similar to the expression profile achieved with a full-size replication-defective HSV-1 recombinant (8117/43). We also examine whether PEI or HSV-1 amplicon-mediated gene transfer could facilitate assessment of the biological effects induced by a dominant negative FGF receptor-1 mutant to model the reduced FGF signalling thought to occur in Parkinson’s disease

    Seeing is Worse than Believing: Reading People’s Minds Better than Computer-Vision Methods Recognize Actions

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    We had human subjects perform a one-out-of-six class action recognition task from video stimuli while undergoing functional magnetic resonance imaging (fMRI). Support-vector machines (SVMs) were trained on the recovered brain scans to classify actions observed during imaging, yielding average classification accuracy of 69.73% when tested on scans from the same subject and of 34.80% when tested on scans from different subjects. An apples-to-apples comparison was performed with all publicly available software that implements state-of-the-art action recognition on the same video corpus with the same cross-validation regimen and same partitioning into training and test sets, yielding classification accuracies between 31.25% and 52.34%. This indicates that one can read people’s minds better than state-of-the-art computer-vision methods can perform action recognition.This work was supported, in part, by the Center for Brains, Minds and Machines (CBMM), funded by NSF STC award CCF - 1231216. AB, DPB, NS, and JMS were supported, in part, by Army Research Laboratory (ARL) Cooperative Agreement W911NF-10-2-0060, AB, in part, by the Center forBrains, Minds and Machines (CBMM), funded by NSF STC award CCF-1231216, WC, CX, and JJC, in part, by ARL Cooperative Agreement W911NF-10-2-0062 and NSF CAREER grant IIS-0845282, CDF, in part, by NSF grant CNS-0855157, CH and SJH, in part, by the McDonnell Foundation, and BAP, in part, by Science Foundation Ireland grant 09/IN.1/I2637

    Magnetic interactions between radical pairs in chiral graphene nanoribbons

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    Open-shell graphene nanoribbons have become promising candidates for future applications, including quantum technologies. Here, we characterize magnetic states hosted by chiral graphene nanoribbons (chGNRs). The substitution of a hydrogen atom at the chGNR edge by a ketone effectively adds one pz electron to the π-electron network, producing an unpaired π-radical. A similar scenario occurs for regular ketone-functionalized chGNRs in which one ketone is missing. Two such radical states can interact via exchange coupling, and we study those interactions as a function of their relative position, which includes a remarkable dependence on the chirality, as well as on the nature of the surrounding ribbon, that is, with or without ketone functionalization. Besides, we determine the parameters whereby this type of system with oxygen heteroatoms can be adequately described within the widely used mean-field Hubbard model. Altogether, we provide insight to both theoretically model and devise GNR-based nanostructures with tunable magnetic properties.We acknowledge financial support from the MCIN/AEI/10.13039/501100011033 (Grants PID2019-107338RB-C62, PID2019-107338RB-C63, PID2020-115406GB-I00, PCI2019-111933-2 (FLAG-ERA grant LEGOCHIP), and Juan de la Cierva Grant FJC2019-041202-I), the European Union’s Horizon 2020 research and innovation program (FET-OPEN project SPRING, Grant No. 863098 and Marie SkƂodowska-Curie Actions Individual Fellowship No. 101022150), the Xunta de Galicia (Centro Singular de InvestigaciĂłn de Galicia, 2019-2022, Grant ED431G2019/03), the European Regional Development Fund, the Basque Government (IT-1255-19), the Basque Government (PIBA Grant PI_2020_1_0014), the Basque Departamento de EducaciĂłn through the Ph.D. scholarship No. PRE_2020_2_0049 (S.S.), the Spanish Research Council (LINKC20002).Peer reviewe

    Functional Inequality in Latin America: News from the Twentieth Century

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    We report on a novel approach for the measurement of gas adsorption in microporous solids using X-ray computed tomography (CT) that we refer to as digital adsorption. Similar to conventional macroscopic methods, the proposed protocol combines observations with an inert and an adsorbing gas to produce equilibrium isotherms in terms of the truly measurable quantity in an adsorption experiment, namely the surface excess. Most significantly, X-ray CT allows probing the adsorption process in three dimensions, so as to build spatially-resolved adsorption isotherms with a resolution of approximately 10 mm3 within a fixed-bed column. Experiments have been carried out at 25 C and in the pressure range 1-30bar using CO2 on activated carbon, zeolite 13X and glass beads (as control material), and results are validated against literature data. A scaling approach was applied to analyze the whole population of measured adsorption isotherms (~7600), leading to single universal adsorption isotherm curves that are descriptive of all voxels for a given adsorbate-adsorbent system. By analyzing the adsorption heterogeneity at multiple length scales (1 mm3 to 1 cm3), packing heterogeneity was identified as the main contributor for the larger spatial variability in the adsorbed amount observed for the activated carbon rods as compared to zeolite pellets. We also show that this technique is readily applicable to a large spectrum of commercial porous solids, and that it can be further extended to weakly adsorbing materials with appropriate protocols that reduce measurement uncertainties. As such, the obtained results prove the feasibility of digital adsorption and highlight substantial opportunities for its wider use in the field of adsorptive characterization of porous solids

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Standalone vertex ïŹnding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ Îł, H → Z Z∗ →4l and H →W W∗ →lÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon Ό\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, ΌΌ\mu\mu or eΌe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde
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