6,063 research outputs found

    Book review: The Learning Cycle: Insights for Faithful Teaching from Neuroscience and the Social Sciences

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    Book Revie

    Multisensory Integration Sites Identified by Perception of Spatial Wavelet Filtered Visual Speech Gesture Information

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    Perception of speech is improved when presentation of the audio signal is accompanied by concordant visual speech gesture information. This enhancement is most prevalent when the audio signal is degraded. One potential means by which the brain affords perceptual enhancement is thought to be through the integration of concordant information from multiple sensory channels in a common site of convergence, multisensory integration (MSI) sites. Some studies have identified potential sites in the superior temporal gyrus/sulcus (STG/S) that are responsive to multisensory information from the auditory speech signal and visual speech movement. One limitation of these studies is that they do not control for activity resulting from attentional modulation cued by such things as visual information signaling the onsets and offsets of the acoustic speech signal, as well as activity resulting from MSI of properties of the auditory speech signal with aspects of gross visual motion that are not specific to place of articulation information. This fMRI experiment uses spatial wavelet bandpass filtered Japanese sentences presented with background multispeaker audio noise to discern brain activity reflecting MSI induced by auditory and visual correspondence of place of articulation information that controls for activity resulting from the above-mentioned factors. The experiment consists of a low-frequency (LF) filtered condition containing gross visual motion of the lips, jaw, and head without specific place of articulation information, a midfrequency (MF) filtered condition containing place of articulation information, and an unfiltered (UF) condition. Sites of MSI selectively induced by auditory and visual correspondence of place of articulation information were determined by the presence of activity for both the MF and UF conditions relative to the LF condition. Based on these criteria, sites of MSI were found predominantly in the left middle temporal gyrus (MTG), and the left STG/S (including the auditory cortex). By controlling for additional factors that could also induce greater activity resulting from visual motion information, this study identifies potential MSI sites that we believe are involved with improved speech perception intelligibility

    Quantum mutual information of an entangled state propagating through a fast-light medium

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    Although it is widely accepted that classical information cannot travel faster than the speed of light in vacuum, the behavior of quantum correlations and quantum information propagating through actively-pumped fast-light media has not been studied in detail. To investigate this behavior, we send one half of an entangled state of light through a gain-assisted fast-light medium and detect the remaining quantum correlations. We show that the quantum correlations can be advanced by a small fraction of the correlation time while the entanglement is preserved even in the presence of noise added by phase-insensitive gain. Additionally, although we observe an advance of the peak of the quantum mutual information between the modes, we find that the degradation of the mutual information due to the added noise appears to prevent an advancement of the leading edge. In contrast, we show that both the leading and trailing edges of the mutual information in a slow-light system can be significantly delayed

    Neonatal NMDA receptor blockade disrupts spike timing and glutamatergic synapses in fast spiking interneurons in a NMDA receptor hypofunction model of schizophrenia

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    The dysfunction of parvalbumin-positive, fast-spiking interneurons (FSI) is considered a primary contributor to the pathophysiology of schizophrenia (SZ), but deficits in FSI physiology have not been explicitly characterized. We show for the first time, that a widely-employed model of schizophrenia minimizes first spike latency and increases GluN2B-mediated current in neocortical FSIs. The reduction in FSI first-spike latency coincides with reduced expression of the Kv1.1 potassium channel subunit which provides a biophysical explanation for the abnormal spiking behavior. Similarly, the increase in NMDA current coincides with enhanced expression of the GluN2B NMDA receptor subunit, specifically in FSIs. In this study mice were treated with the NMDA receptor antagonist, MK-801, during the first week of life. During adolescence, we detected reduced spike latency and increased GluN2B-mediated NMDA current in FSIs, which suggests transient disruption of NMDA signaling during neonatal development exerts lasting changes in the cellular and synaptic physiology of neocortical FSIs. Overall, we propose these physiological disturbances represent a general impairment to the physiological maturation of FSIs which may contribute to schizophrenia-like behaviors produced by this model

    Exploring the nuclear pion dispersion relation through the anomalous coupling of photon to photon and neutral pion

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    We investigate the possibility of measuring the pion dispersion relation in nuclear matter through the anomalous coupling in the reaction \gamma - \gamma' \pi_0. It is shown that this reaction permits the study of pionic modes for space-like momenta. If the pion is softened in nuclear matter due to mixing with the delta-hole state, significant strength for this reaction is expected to move into the space-like region. Competing background processes are evaluated, and it is concluded that useful insight can be obtained experimentally, but only through a difficult exclusive measurement

    A Tale of Two Narrow-Line Regions: Ionization, Kinematics, and Spectral Energy Distributions for a Local Pair of Merging Obscured Active Galaxies

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    We explore the gas ionization and kinematics, as well as the optical--IR spectral energy distributions for UGC 11185, a nearby pair of merging galaxies hosting obscured active galactic nuclei (AGNs), also known as SDSS J181611.72+423941.6 and J181609.37+423923.0 (J1816NE and J1816SW, z≈0.04z \approx 0.04). Due to the wide separation between these interacting galaxies (∼23\sim 23 kpc), observations of these objects provide a rare glimpse of the concurrent growth of supermassive black holes at an early merger stage. We use BPT line diagnostics to show that the full extent of the narrow line emission in both galaxies is photoionized by an AGN and confirm the existence of a 10-kpc-scale ionization cone in J1816NE, while in J1816SW the AGN narrow-line region is much more compact (1--2 kpc) and relatively undisturbed. Our observations also reveal the presence of ionized gas that nearly spans the entire distance between the galaxies which is likely in a merger-induced tidal stream. In addition, we carry out a spectral analysis of the X-ray emission using data from {\em XMM-Newton}. These galaxies represent a useful pair to explore how the [\ion{O}{3}] luminosity of an AGN is dependent on the size of the region used to explore the extended emission. Given the growing evidence for AGN "flickering" over short timescales, we speculate that the appearances and impact of these AGNs may change multiple times over the course of the galaxy merger, which is especially important given that these objects are likely the progenitors of the types of systems commonly classified as "dual AGNs."Comment: 15 pages, 10 figures, accepted by the Astrophysical Journa

    Sodium Bose-Einstein Condensates in an Optical Lattice

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    The phase transition from a superfluid to a Mott insulator has been observed in a 23^{23}Na Bose-Einstein condensate. A dye laser detuned ≈5\approx 5nm red of the Na 323^2S→32 \to 3^2P1/2_{1/2} transition was used to form the three dimensional optical lattice. The heating effects of the small detuning as well as the three-body decay processes constrained the timescale of the experiment. Certain lattice detunings were found to induce a large loss of atoms. These loss features were shown to be due to photoassociation of atoms to vibrational levels in the Na2_2 (1)3Σg+(1) ^3\Sigma_g^+ state.Comment: Figures somewhat compromised due to size reductio

    The Poetics of Revolution: Cultures, Practices, and Politics of Anti-Colonialism in Iraq, 1932-1960

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    This dissertation uses Iraqi poetry, memoirs, and newspapers alongside British and American archival documents to analyze the cultural dynamics of popular opposition to foreign political, economic, and cultural hegemony in the post-mandatory state. It argues that the varied instances of political, social, and cultural revolution during this period were rooted in a fundamental commitment to anti-colonialism and national liberation and illustrates the historical contingency of ideological conflict and sectarian commitments in nationalist narratives used by scholars to classify and categorize revolutionary movements as fragmentary expressions of local grievances and demonstrate the global dimensions of these revolutionary currents. By shifting attention from the domain of elite politics and the ideological debates of isolated intellectual circles toward the cultural arena of popular political poetry and the social dimensions of tribal disintegration, urban migration, and capitalist dislocation, the dissertation shows how popular poets appealed to diverse populations of peasants, workers, and students and helped to mobilize popular movements that transcended sectarian and class conflicts. The dissertation shows that the Iraqi public overwhelmingly refused to consider colonialism as part of the historical past as long as power remained in the hands of foreign officials and the old colonial elite and virtually all revolutionary currents in this period were aimed at eradicating the vestiges of colonialism. It illustrates the ways in which social change and cultural politics contributed to the development of mass politics and the emergence of a public sphere and fundamentally shaped revolutionary anti-colonial movements and challenged competing loyalties to class, sect, and ideology. The dissertation analyzes the social role of popular poetry in shaping national political discourse and mobilizing mass political action and contends that the binary dichotomies of Iraqist and pan-Arabist nationalism or radical and reactionary social ideologies have obscured the national solidarities constructed through public protest and opposition to British and American policies in Iraq and the Arab world. By juxtaposing the testimony of immediate and retrospective historical texts, like poems and memoirs, the dissertation illustrates the extent to which these ideological narratives were applied retroactively to justify post-revolutionary political agendas.PHDHistoryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/100047/1/kevjones_1.pd
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