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Sample records for hierarchically organized auditory

  1. Hierarchical organization of speech perception in human auditory cortex

    Directory of Open Access Journals (Sweden)

    Colin eHumphries

    2014-12-01

    Full Text Available Human speech consists of a variety of articulated sounds that vary dynamically in spectral composition. We investigated the neural activity associated with the perception of two types of speech segments: (a the period of rapid spectral transition occurring at the beginning of a stop-consonant vowel (CV syllable and (b the subsequent spectral steady-state period occurring during the vowel segment of the syllable. Functional magnetic resonance imaging (fMRI was recorded while subjects listened to series of synthesized CV syllables and non-phonemic control sounds. Adaptation to specific sound features was measured by varying either the transition or steady-state periods of the synthesized sounds. Two spatially distinct brain areas in the superior temporal cortex were found that were sensitive to either the type of adaptation or the type of stimulus. In a relatively large section of the bilateral dorsal superior temporal gyrus (STG, activity varied as a function of adaptation type regardless of whether the stimuli were phonemic or non-phonemic. Immediately adjacent to this region in a more limited area of the ventral STG, increased activity was observed for phonemic trials compared to non-phonemic trials, however, no adaptation effects were found. In addition, a third area in the bilateral medial superior temporal plane showed increased activity to non-phonemic compared to phonemic sounds. The results suggest a multi-stage hierarchical stream for speech sound processing extending ventrolaterally from the superior temporal plane to the superior temporal sulcus. At successive stages in this hierarchy, neurons code for increasingly more complex spectrotemporal features. At the same time, these representations become more abstracted from the original acoustic form of the sound.

  2. Segregation of vowels and consonants in human auditory cortex: Evidence for distributed hierarchical organization

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    Jonas eObleser

    2010-12-01

    Full Text Available The speech signal consists of a continuous stream of consonants and vowels, which must be de– and encoded in human auditory cortex to ensure the robust recognition and categorization of speech sounds. We used small-voxel functional magnetic resonance imaging (fMRI to study information encoded in local brain activation patterns elicited by consonant-vowel syllables, and by a control set of noise bursts.First, activation of anterior–lateral superior temporal cortex was seen when controlling for unspecific acoustic processing (syllables versus band-passed noises, in a classic subtraction-based design. Second, a classifier algorithm, which was trained and tested iteratively on data from all subjects to discriminate local brain activation patterns, yielded separations of cortical patches discriminative of vowel category versus patches discriminative of stop-consonant category across the entire superior temporal cortex, yet with regional differences in average classification accuracy. Overlap (voxels correctly classifying both speech sound categories was surprisingly sparse. Third, lending further plausibility to the results, classification of speech–noise differences was generally superior to speech–speech classifications, with the notable exception of a left anterior region, where speech–speech classification accuracies were significantly better.These data demonstrate that acoustic-phonetic features are encoded in complex yet sparsely overlapping local patterns of neural activity distributed hierarchically across different regions of the auditory cortex. The redundancy apparent in these multiple patterns may partly explain the robustness of phonemic representations.

  3. Expectation and attention in hierarchical auditory prediction.

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    Chennu, Srivas; Noreika, Valdas; Gueorguiev, David; Blenkmann, Alejandro; Kochen, Silvia; Ibáñez, Agustín; Owen, Adrian M; Bekinschtein, Tristan A

    2013-07-03

    Hierarchical predictive coding suggests that attention in humans emerges from increased precision in probabilistic inference, whereas expectation biases attention in favor of contextually anticipated stimuli. We test these notions within auditory perception by independently manipulating top-down expectation and attentional precision alongside bottom-up stimulus predictability. Our findings support an integrative interpretation of commonly observed electrophysiological signatures of neurodynamics, namely mismatch negativity (MMN), P300, and contingent negative variation (CNV), as manifestations along successive levels of predictive complexity. Early first-level processing indexed by the MMN was sensitive to stimulus predictability: here, attentional precision enhanced early responses, but explicit top-down expectation diminished it. This pattern was in contrast to later, second-level processing indexed by the P300: although sensitive to the degree of predictability, responses at this level were contingent on attentional engagement and in fact sharpened by top-down expectation. At the highest level, the drift of the CNV was a fine-grained marker of top-down expectation itself. Source reconstruction of high-density EEG, supported by intracranial recordings, implicated temporal and frontal regions differentially active at early and late levels. The cortical generators of the CNV suggested that it might be involved in facilitating the consolidation of context-salient stimuli into conscious perception. These results provide convergent empirical support to promising recent accounts of attention and expectation in predictive coding.

  4. Hierarchical processing of auditory objects in humans.

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    Sukhbinder Kumar

    2007-06-01

    Full Text Available This work examines the computational architecture used by the brain during the analysis of the spectral envelope of sounds, an important acoustic feature for defining auditory objects. Dynamic causal modelling and Bayesian model selection were used to evaluate a family of 16 network models explaining functional magnetic resonance imaging responses in the right temporal lobe during spectral envelope analysis. The models encode different hypotheses about the effective connectivity between Heschl's Gyrus (HG, containing the primary auditory cortex, planum temporale (PT, and superior temporal sulcus (STS, and the modulation of that coupling during spectral envelope analysis. In particular, we aimed to determine whether information processing during spectral envelope analysis takes place in a serial or parallel fashion. The analysis provides strong support for a serial architecture with connections from HG to PT and from PT to STS and an increase of the HG to PT connection during spectral envelope analysis. The work supports a computational model of auditory object processing, based on the abstraction of spectro-temporal "templates" in the PT before further analysis of the abstracted form in anterior temporal lobe areas.

  5. Hierarchical organization versus self-organization

    OpenAIRE

    Busseniers, Evo

    2014-01-01

    In this paper we try to define the difference between hierarchical organization and self-organization. Organization is defined as a structure with a function. So we can define the difference between hierarchical organization and self-organization both on the structure as on the function. In the next two chapters these two definitions are given. For the structure we will use some existing definitions in graph theory, for the function we will use existing theory on (self-)organization. In the t...

  6. Sensory Hierarchical Organization and Reading.

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    Skapof, Jerome

    The purpose of this study was to judge the viability of an operational approach aimed at assessing response styles in reading using the hypothesis of sensory hierarchical organization. A sample of 103 middle-class children from a New York City public school, between the ages of five and seven, took part in a three phase experiment. Phase one…

  7. Sensorineural hearing loss and auditory perceptual organization

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    Hall, Joseph W.; Grose, John H.; Buss, Emily

    2004-05-01

    This talk will consider the implications of sensorineural hearing loss for auditory perceptual organization. In everyday environments, the listener is often faced with the difficulty of processing a target sound that intermingles acoustically with one or more extraneous sounds. Under such circumstances, several auditory processes enable the complex waveforms reaching the two ears to be interpreted in terms of putative auditory objects giving rise to the target and extraneous sounds. Such processes of perceptual organization depend upon the central analysis of cues that allow distributed spectral information to be either linked together or split apart on the basis of details related to such variables as synchrony of onset/modulation, harmonic relation, rhythm, and interaural differences. Efficient perceptual organization must depend not only upon such central auditory analyses but also upon the fidelity with which the peripheral auditory system encodes the spectral and temporal characteristics of sound. We will consider the implications of sensorineural hearing loss for perceptual organization in terms of both peripheral and central auditory processes.

  8. HIERARCHICAL ORGANIZATION OF INFORMATION, IN RELATIONAL DATABASES

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    Demian Horia

    2008-05-01

    Full Text Available In this paper I will present different types of representation, of hierarchical information inside a relational database. I also will compare them to find the best organization for specific scenarios.

  9. Hierarchical self-organization of tectonic plates

    OpenAIRE

    2010-01-01

    The Earth's surface is subdivided into eight large tectonic plates and many smaller ones. We reconstruct the plate tessellation history and demonstrate that both large and small plates display two distinct hierarchical patterns, described by different power-law size-relationships. While small plates display little organisational change through time, the structure of the large plates oscillate between minimum and maximum hierarchical tessellations. The organization of large plates rapidly chan...

  10. Dynamic Organization of Hierarchical Memories.

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    Kurikawa, Tomoki; Kaneko, Kunihiko

    2016-01-01

    In the brain, external objects are categorized in a hierarchical way. Although it is widely accepted that objects are represented as static attractors in neural state space, this view does not take account interaction between intrinsic neural dynamics and external input, which is essential to understand how neural system responds to inputs. Indeed, structured spontaneous neural activity without external inputs is known to exist, and its relationship with evoked activities is discussed. Then, how categorical representation is embedded into the spontaneous and evoked activities has to be uncovered. To address this question, we studied bifurcation process with increasing input after hierarchically clustered associative memories are learned. We found a "dynamic categorization"; neural activity without input wanders globally over the state space including all memories. Then with the increase of input strength, diffuse representation of higher category exhibits transitions to focused ones specific to each object. The hierarchy of memories is embedded in the transition probability from one memory to another during the spontaneous dynamics. With increased input strength, neural activity wanders over a narrower state space including a smaller set of memories, showing more specific category or memory corresponding to the applied input. Moreover, such coarse-to-fine transitions are also observed temporally during transient process under constant input, which agrees with experimental findings in the temporal cortex. These results suggest the hierarchy emerging through interaction with an external input underlies hierarchy during transient process, as well as in the spontaneous activity.

  11. The Harmonic Organization of Auditory Cortex

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    Xiaoqin eWang

    2013-12-01

    Full Text Available A fundamental structure of sounds encountered in the natural environment is the harmonicity. Harmonicity is an essential component of music found in all cultures. It is also a unique feature of vocal communication sounds such as human speech and animal vocalizations. Harmonics in sounds are produced by a variety of acoustic generators and reflectors in the natural environment, including vocal apparatuses of humans and animal species as well as music instruments of many types. We live in an acoustic world full of harmonicity. Given the widespread existence of the harmonicity in many aspects of the hearing environment, it is natural to expect that it be reflected in the evolution and development of the auditory systems of both humans and animals, in particular the auditory cortex. Recent neuroimaging and neurophysiology experiments have identified regions of non-primary auditory cortex in humans and non-human primates that have selective responses to harmonic pitches. Accumulating evidence has also shown that neurons in many regions of the auditory cortex exhibit characteristic responses to harmonically related frequencies beyond the range of pitch. Together, these findings suggest that a fundamental organizational principle of auditory cortex is based on the harmonicity. Such an organization likely plays an important role in music processing by the brain. It may also form the basis of the preference for particular classes of music and voice sounds.

  12. Hierarchical self-organization of tectonic plates

    CERN Document Server

    Morra, Gabriele; Müller, R Dietmar

    2010-01-01

    The Earth's surface is subdivided into eight large tectonic plates and many smaller ones. We reconstruct the plate tessellation history and demonstrate that both large and small plates display two distinct hierarchical patterns, described by different power-law size-relationships. While small plates display little organisational change through time, the structure of the large plates oscillate between minimum and maximum hierarchical tessellations. The organization of large plates rapidly changes from a weak hierarchy at 120-100 million years ago (Ma) towards a strong hierarchy, which peaked at 65-50, Ma subsequently relaxing back towards a minimum hierarchical structure. We suggest that this fluctuation reflects an alternation between top and bottom driven plate tectonics, revealing a previously undiscovered tectonic cyclicity at a timescale of 100 million years.

  13. Neurophysiological mechanisms involved in auditory perceptual organization

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    Aurélie Bidet-Caulet

    2009-09-01

    Full Text Available In our complex acoustic environment, we are confronted with a mixture of sounds produced by several simultaneous sources. However, we rarely perceive these sounds as incomprehensible noise. Our brain uses perceptual organization processes to independently follow the emission of each sound source over time. If the acoustic properties exploited in these processes are well-established, the neurophysiological mechanisms involved in auditory scene analysis have raised interest only recently. Here, we review the studies investigating these mechanisms using electrophysiological recordings from the cochlear nucleus to the auditory cortex, in animals and humans. Their findings reveal that basic mechanisms such as frequency selectivity, forward suppression and multi-second habituation shape the automatic brain responses to sounds in a way that can account for several important characteristics of perceptual organization of both simultaneous and successive sounds. One challenging question remains unresolved: how are the resulting activity patterns integrated to yield the corresponding conscious perceptsµ

  14. Hierarchical Self-organization of Complex Systems

    Institute of Scientific and Technical Information of China (English)

    CHAI Li-he; WEN Dong-sheng

    2004-01-01

    Researches on organization and structure in complex systems are academic and industrial fronts in modern sciences. Though many theories are tentatively proposed to analyze complex systems, we still lack a rigorous theory on them. Complex systems possess various degrees of freedom, which means that they should exhibit all kinds of structures. However, complex systems often show similar patterns and structures. Then the question arises why such similar structures appear in all kinds of complex systems. The paper outlines a theory on freedom degree compression and the existence of hierarchical self-organization for all complex systems is found. It is freedom degree compression and hierarchical self-organization that are responsible for the existence of these similar patterns or structures observed in the complex systems.

  15. Hierarchical organization of cognitive memory.

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    Mishkin, M; Suzuki, W A; Gadian, D G; Vargha-Khadem, F

    1997-10-29

    This paper addresses the question of the organization of memory processes within the medial temporal lobe. Evidence obtained in patients with late-onset amnesia resulting from medial temporal pathology has given rise to two opposing interpretations of the effects of such damage on long-term cognitive memory. One view is that cognitive memory, including memory for both facts and events, is served in a unitary manner by the hippocampus and its surrounding cortices; the other is that the basic function affected in amnesia is event memory, the memory for factual material often showing substantial preservation. Recent findings in patients with amnesia resulting from relatively selective hippocampal damage sustained early in life suggest a possible reconciliation of the two views. The new findings suggest that the hippocampus may be especially important for event as opposed to fact memory, with the surrounding cortical areas contributing to both. Evidence from neuroanatomical and neurobehavioural studies in monkeys is presented in support of this proposal.

  16. Relative Priming of Temporal Local-Global Levels in Auditory Hierarchical Stimuli

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    List, Alexandra; Justus, Timothy

    2009-01-01

    Priming is a useful tool for ascertaining the circumstances under which previous experiences influence behavior. Previously, using hierarchical stimuli, we demonstrated that selectively attending to one temporal scale of an auditory stimulus improved subsequent attention to a repeated (vs. changed) temporal scale, i.e., we demonstrated inter-trial auditory temporal level-priming. Here, we have extended those results to address whether level-priming relied on absolute or relative temporal information. Both relative and absolute temporal information are important in auditory perception: speech and music can be recognized over various temporal scales, but become uninterpretable to a listener when presented too quickly or slowly. We first confirmed that temporal level-priming generalized over new temporal scales. Second, in the context of multiple temporal scales, we found that temporal level-priming operates predominantly on the basis of relative, rather than absolute, temporal information. These findings are discussed in the context of expectancies and relational invariance in audition. PMID:20045889

  17. Efficient promotion strategies in hierarchical organizations

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    Pluchino, Alessandro; Rapisarda, Andrea; Garofalo, Cesare

    2011-10-01

    The Peter principle has recently been investigated by means of an agent-based simulation, and its validity has been numerically corroborated. It has been confirmed that, within certain conditions, it can really influence in a negative way the efficiency of a pyramidal organization adopting meritocratic promotions. It was also found that, in order to bypass these effects, alternative promotion strategies should be adopted, as for example a random selection choice. In this paper, within the same line of research, we study promotion strategies in a more realistic hierarchical and modular organization, and we show the robustness of our previous results, extending their validity to a more general context. We also discuss why the adoption of these strategies could be useful for real organizations.

  18. Tonotopic organization of human auditory association cortex.

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    Cansino, S; Williamson, S J; Karron, D

    1994-11-07

    Neuromagnetic studies of responses in human auditory association cortex for tone burst stimuli provide evidence for a tonotopic organization. The magnetic source image for the 100 ms component evoked by the onset of a tone is qualitatively similar to that of primary cortex, with responses lying deeper beneath the scalp for progressively higher tone frequencies. However, the tonotopic sequence of association cortex in three subjects is found largely within the superior temporal sulcus, although in the right hemisphere of one subject some sources may be closer to the inferior temporal sulcus. The locus of responses for individual subjects suggests a progression across the cortical surface that is approximately proportional to the logarithm of the tone frequency, as observed previously for primary cortex, with the span of 10 mm for each decade in frequency being comparable for the two areas.

  19. Myosin VIIA, important for human auditory function, is necessary for Drosophila auditory organ development.

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    Sokol V Todi

    Full Text Available BACKGROUND: Myosin VIIA (MyoVIIA is an unconventional myosin necessary for vertebrate audition [1]-[5]. Human auditory transduction occurs in sensory hair cells with a staircase-like arrangement of apical protrusions called stereocilia. In these hair cells, MyoVIIA maintains stereocilia organization [6]. Severe mutations in the Drosophila MyoVIIA orthologue, crinkled (ck, are semi-lethal [7] and lead to deafness by disrupting antennal auditory organ (Johnston's Organ, JO organization [8]. ck/MyoVIIA mutations result in apical detachment of auditory transduction units (scolopidia from the cuticle that transmits antennal vibrations as mechanical stimuli to JO. PRINCIPAL FINDINGS: Using flies expressing GFP-tagged NompA, a protein required for auditory organ organization in Drosophila, we examined the role of ck/MyoVIIA in JO development and maintenance through confocal microscopy and extracellular electrophysiology. Here we show that ck/MyoVIIA is necessary early in the developing antenna for initial apical attachment of the scolopidia to the articulating joint. ck/MyoVIIA is also necessary to maintain scolopidial attachment throughout adulthood. Moreover, in the adult JO, ck/MyoVIIA genetically interacts with the non-muscle myosin II (through its regulatory light chain protein and the myosin binding subunit of myosin II phosphatase. Such genetic interactions have not previously been observed in scolopidia. These factors are therefore candidates for modulating MyoVIIA activity in vertebrates. CONCLUSIONS: Our findings indicate that MyoVIIA plays evolutionarily conserved roles in auditory organ development and maintenance in invertebrates and vertebrates, enhancing our understanding of auditory organ development and function, as well as providing significant clues for future research.

  20. Hierarchical effects of task engagement on amplitude modulation encoding in auditory cortex.

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    Niwa, Mamiko; O'Connor, Kevin N; Engall, Elizabeth; Johnson, Jeffrey S; Sutter, M L

    2015-01-01

    We recorded from middle lateral belt (ML) and primary (A1) auditory cortical neurons while animals discriminated amplitude-modulated (AM) sounds and also while they sat passively. Engagement in AM discrimination improved ML and A1 neurons' ability to discriminate AM with both firing rate and phase-locking; however, task engagement affected neural AM discrimination differently in the two fields. The results suggest that these two areas utilize different AM coding schemes: a "single mode" in A1 that relies on increased activity for AM relative to unmodulated sounds and a "dual-polar mode" in ML that uses both increases and decreases in neural activity to encode modulation. In the dual-polar ML code, nonsynchronized responses might play a special role. The results are consistent with findings in the primary and secondary somatosensory cortices during discrimination of vibrotactile modulation frequency, implicating a common scheme in the hierarchical processing of temporal information among different modalities. The time course of activity differences between behaving and passive conditions was also distinct in A1 and ML and may have implications for auditory attention. At modulation depths ≥ 16% (approximately behavioral threshold), A1 neurons' improvement in distinguishing AM from unmodulated noise is relatively constant or improves slightly with increasing modulation depth. In ML, improvement during engagement is most pronounced near threshold and disappears at highly suprathreshold depths. This ML effect is evident later in the stimulus, and mainly in nonsynchronized responses. This suggests that attention-related increases in activity are stronger or longer-lasting for more difficult stimuli in ML.

  1. Spatial organization of tettigoniid auditory receptors: insights from neuronal tracing.

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    Strauß, Johannes; Lehmann, Gerlind U C; Lehmann, Arne W; Lakes-Harlan, Reinhard

    2012-11-01

    The auditory sense organ of Tettigoniidae (Insecta, Orthoptera) is located in the foreleg tibia and consists of scolopidial sensilla which form a row termed crista acustica. The crista acustica is associated with the tympana and the auditory trachea. This ear is a highly ordered, tonotopic sensory system. As the neuroanatomy of the crista acustica has been documented for several species, the most distal somata and dendrites of receptor neurons have occasionally been described as forming an alternating or double row. We investigate the spatial arrangement of receptor cell bodies and dendrites by retrograde tracing with cobalt chloride solution. In six tettigoniid species studied, distal receptor neurons are consistently arranged in double-rows of somata rather than a linear sequence. This arrangement of neurons is shown to affect 30-50% of the overall auditory receptors. No strict correlation of somata positions between the anterio-posterior and dorso-ventral axis was evident within the distal crista acustica. Dendrites of distal receptors occasionally also occur in a double row or are even massed without clear order. Thus, a substantial part of auditory receptors can deviate from a strictly straight organization into a more complex morphology. The linear organization of dendrites is not a morphological criterion that allows hearing organs to be distinguished from nonhearing sense organs serially homologous to ears in all species. Both the crowded arrangement of receptor somata and dendrites may result from functional constraints relating to frequency discrimination, or from developmental constraints of auditory morphogenesis in postembryonic development.

  2. The structure and function of auditory chordotonal organs in insects.

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    Yack, Jayne E

    2004-04-15

    Insects are capable of detecting a broad range of acoustic signals transmitted through air, water, or solids. Auditory sensory organs are morphologically diverse with respect to their body location, accessory structures, and number of sensilla, but remarkably uniform in that most are innervated by chordotonal organs. Chordotonal organs are structurally complex Type I mechanoreceptors that are distributed throughout the insect body and function to detect a wide range of mechanical stimuli, from gross motor movements to air-borne sounds. At present, little is known about how chordotonal organs in general function to convert mechanical stimuli to nerve impulses, and our limited understanding of this process represents one of the major challenges to the study of insect auditory systems today. This report reviews the literature on chordotonal organs innervating insect ears, with the broad intention of uncovering some common structural specializations of peripheral auditory systems, and identifying new avenues for research. A general overview of chordotonal organ ultrastructure is presented, followed by a summary of the current theories on mechanical coupling and transduction in monodynal, mononematic, Type 1 scolopidia, which characteristically innervate insect ears. Auditory organs of different insect taxa are reviewed, focusing primarily on tympanal organs, and with some consideration to Johnston's and subgenual organs. It is widely accepted that insect hearing organs evolved from pre-existing proprioceptive chordotonal organs. In addition to certain non-neural adaptations for hearing, such as tracheal expansion and cuticular thinning, the chordotonal organs themselves may have intrinsic specializations for sound reception and transduction, and these are discussed. In the future, an integrated approach, using traditional anatomical and physiological techniques in combination with new methodologies in immunohistochemistry, genetics, and biophysics, will assist in

  3. Simulating Self-organization and Interference between Certain Hierarchical Structures.

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    Raczynski, Stanislaw

    2014-10-01

    A model of the dynamics and interactions between organizations with self-organizing hierarchical structures is presented for discrete events. The active objects of the model are individuals (people, organization members). The parameters of an individual are ability, corruption level, resources, and lust for power, among others. Three organizations are generated and interact with each other, attempting to gain more members and power. The individuals appear and disappear, due to a simple 'birth-and-death' process. If an individual disappears from the model, a corresponding reconfiguration in the hierarchical structure occurs. The organization's growth and macro-patterns are the result of the activities of the individuals. The aim of the simulation is to visualize the evolution of the organizations and the stability of the whole system. A 'steady state' for the model is rare; instead, in most parameter configurations, the model enters into oscillations.

  4. Temporal Organization of Sound Information in Auditory Memory

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    Kun Song

    2017-06-01

    Full Text Available Memory is a constructive and organizational process. Instead of being stored with all the fine details, external information is reorganized and structured at certain spatiotemporal scales. It is well acknowledged that time plays a central role in audition by segmenting sound inputs into temporal chunks of appropriate length. However, it remains largely unknown whether critical temporal structures exist to mediate sound representation in auditory memory. To address the issue, here we designed an auditory memory transferring study, by combining a previously developed unsupervised white noise memory paradigm with a reversed sound manipulation method. Specifically, we systematically measured the memory transferring from a random white noise sound to its locally temporal reversed version on various temporal scales in seven experiments. We demonstrate a U-shape memory-transferring pattern with the minimum value around temporal scale of 200 ms. Furthermore, neither auditory perceptual similarity nor physical similarity as a function of the manipulating temporal scale can account for the memory-transferring results. Our results suggest that sounds are not stored with all the fine spectrotemporal details but are organized and structured at discrete temporal chunks in long-term auditory memory representation.

  5. Temporal Organization of Sound Information in Auditory Memory

    Science.gov (United States)

    Song, Kun; Luo, Huan

    2017-01-01

    Memory is a constructive and organizational process. Instead of being stored with all the fine details, external information is reorganized and structured at certain spatiotemporal scales. It is well acknowledged that time plays a central role in audition by segmenting sound inputs into temporal chunks of appropriate length. However, it remains largely unknown whether critical temporal structures exist to mediate sound representation in auditory memory. To address the issue, here we designed an auditory memory transferring study, by combining a previously developed unsupervised white noise memory paradigm with a reversed sound manipulation method. Specifically, we systematically measured the memory transferring from a random white noise sound to its locally temporal reversed version on various temporal scales in seven experiments. We demonstrate a U-shape memory-transferring pattern with the minimum value around temporal scale of 200 ms. Furthermore, neither auditory perceptual similarity nor physical similarity as a function of the manipulating temporal scale can account for the memory-transferring results. Our results suggest that sounds are not stored with all the fine spectrotemporal details but are organized and structured at discrete temporal chunks in long-term auditory memory representation. PMID:28674512

  6. Conceptual hierarchical modeling to describe wetland plant community organization

    Science.gov (United States)

    Little, A.M.; Guntenspergen, G.R.; Allen, T.F.H.

    2010-01-01

    Using multivariate analysis, we created a hierarchical modeling process that describes how differently-scaled environmental factors interact to affect wetland-scale plant community organization in a system of small, isolated wetlands on Mount Desert Island, Maine. We followed the procedure: 1) delineate wetland groups using cluster analysis, 2) identify differently scaled environmental gradients using non-metric multidimensional scaling, 3) order gradient hierarchical levels according to spatiotem-poral scale of fluctuation, and 4) assemble hierarchical model using group relationships with ordination axes and post-hoc tests of environmental differences. Using this process, we determined 1) large wetland size and poor surface water chemistry led to the development of shrub fen wetland vegetation, 2) Sphagnum and water chemistry differences affected fen vs. marsh / sedge meadows status within small wetlands, and 3) small-scale hydrologic differences explained transitions between forested vs. non-forested and marsh vs. sedge meadow vegetation. This hierarchical modeling process can help explain how upper level contextual processes constrain biotic community response to lower-level environmental changes. It creates models with more nuanced spatiotemporal complexity than classification and regression tree procedures. Using this process, wetland scientists will be able to generate more generalizable theories of plant community organization, and useful management models. ?? Society of Wetland Scientists 2009.

  7. Self-organized Criticality in Hierarchical Brain Network

    Institute of Scientific and Technical Information of China (English)

    YANG Qiu-Ying; ZHANG Ying-Yue; CHEN Tian-Lun

    2008-01-01

    It is shown that the cortical brain network of the macaque displays a hierarchically clustered organization and the neuron network shows small-world properties. Now the two factors will be considered in our model and the dynamical behavior of the model will be studied. We study the characters of the model and find that the distribution of avalanche size of the model follows power-law behavior.

  8. Functional organization for musical consonance and tonal pitch hierarchy in human auditory cortex.

    Science.gov (United States)

    Bidelman, Gavin M; Grall, Jeremy

    2014-11-01

    Pitch relationships in music are characterized by their degree of consonance, a hierarchical perceptual quality that distinguishes how pleasant musical chords/intervals sound to the ear. The origins of consonance have been debated since the ancient Greeks. To elucidate the neurobiological mechanisms underlying these musical fundamentals, we recorded neuroelectric brain activity while participants listened passively to various chromatic musical intervals (simultaneously sounding pitches) varying in their perceptual pleasantness (i.e., consonance/dissonance). Dichotic presentation eliminated acoustic and peripheral contributions that often confound explanations of consonance. We found that neural representations for pitch in early human auditory cortex code perceptual features of musical consonance and follow a hierarchical organization according to music-theoretic principles. These neural correlates emerge pre-attentively within ~ 150 ms after the onset of pitch, are segregated topographically in superior temporal gyrus with a rightward hemispheric bias, and closely mirror listeners' behavioral valence preferences for the chromatic tone combinations inherent to music. A perceptual-based organization implies that parallel to the phonetic code for speech, elements of music are mapped within early cerebral structures according to higher-order, perceptual principles and the rules of Western harmony rather than simple acoustic attributes.

  9. Hierarchical clustering techniques for image database organization and summarization

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    Vellaikal, Asha; Kuo, C.-C. Jay

    1998-10-01

    This paper investigates clustering techniques as a method of organizing image databases to support popular visual management functions such as searching, browsing and navigation. Different types of hierarchical agglomerative clustering techniques are studied as a method of organizing features space as well as summarizing image groups by the selection of a few appropriate representatives. Retrieval performance using both single and multiple level hierarchies are experimented with and the algorithms show an interesting relationship between the top k correct retrievals and the number of comparisons required. Some arguments are given to support the use of such cluster-based techniques for managing distributed image databases.

  10. Hierarchical self-organization of non-cooperating individuals

    CERN Document Server

    Nepusz, Tamás

    2013-01-01

    Hierarchy is one of the most conspicuous features of numerous natural, technological and social systems. The underlying structures are typically complex and their most relevant organizational principle is the ordering of the ties among the units they are made of according to a network displaying hierarchical features. In spite of the abundant presence of hierarchy no quantitative theoretical interpretation of the origins of a multi-level, knowledge-based social network exists. Here we introduce an approach which is capable of reproducing the emergence of a multi-levelled network structure based on the plausible assumption that the individuals (representing the nodes of the network) can make the right estimate about the state of their changing environment to a varying degree. Our model accounts for a fundamental feature of knowledge-based organizations: the less capable individuals tend to follow those who are better at solving the problems they all face. We find that relatively simple rules lead to hierarchic...

  11. Specialized prefrontal auditory fields: organization of primate prefrontal-temporal pathways

    Directory of Open Access Journals (Sweden)

    Maria eMedalla

    2014-04-01

    Full Text Available No other modality is more frequently represented in the prefrontal cortex than the auditory, but the role of auditory information in prefrontal functions is not well understood. Pathways from auditory association cortices reach distinct sites in the lateral, orbital, and medial surfaces of the prefrontal cortex in rhesus monkeys. Among prefrontal areas, frontopolar area 10 has the densest interconnections with auditory association areas, spanning a large antero-posterior extent of the superior temporal gyrus from the temporal pole to auditory parabelt and belt regions. Moreover, auditory pathways make up the largest component of the extrinsic connections of area 10, suggesting a special relationship with the auditory modality. Here we review anatomic evidence showing that frontopolar area 10 is indeed the main frontal auditory field as the major recipient of auditory input in the frontal lobe and chief source of output to auditory cortices. Area 10 is thought to be the functional node for the most complex cognitive tasks of multitasking and keeping track of information for future decisions. These patterns suggest that the auditory association links of area 10 are critical for complex cognition. The first part of this review focuses on the organization of prefrontal-auditory pathways at the level of the system and the synapse, with a particular emphasis on area 10. Then we explore ideas on how the elusive role of area 10 in complex cognition may be related to the specialized relationship with auditory association cortices.

  12. Hierarchical self-organization of non-cooperating individuals.

    Directory of Open Access Journals (Sweden)

    Tamás Nepusz

    Full Text Available Hierarchy is one of the most conspicuous features of numerous natural, technological and social systems. The underlying structures are typically complex and their most relevant organizational principle is the ordering of the ties among the units they are made of according to a network displaying hierarchical features. In spite of the abundant presence of hierarchy no quantitative theoretical interpretation of the origins of a multi-level, knowledge-based social network exists. Here we introduce an approach which is capable of reproducing the emergence of a multi-levelled network structure based on the plausible assumption that the individuals (representing the nodes of the network can make the right estimate about the state of their changing environment to a varying degree. Our model accounts for a fundamental feature of knowledge-based organizations: the less capable individuals tend to follow those who are better at solving the problems they all face. We find that relatively simple rules lead to hierarchical self-organization and the specific structures we obtain possess the two, perhaps most important features of complex systems: a simultaneous presence of adaptability and stability. In addition, the performance (success score of the emerging networks is significantly higher than the average expected score of the individuals without letting them copy the decisions of the others. The results of our calculations are in agreement with a related experiment and can be useful from the point of designing the optimal conditions for constructing a given complex social structure as well as understanding the hierarchical organization of such biological structures of major importance as the regulatory pathways or the dynamics of neural networks.

  13. Hierarchically organized soft-materials based on fullerenes

    Science.gov (United States)

    Nakanishi, Takashi

    2009-04-01

    Simple chemical modifications of fullerene (C60) with long aliphatic chains provide novel type amphiphilic molecules playing in organic solvents due to the two different intermolecular interactions, namely π-π on C60 and van der Waals interactions on aliphatic chain moieties, respectively, and open a door developing supramolecular soft-materials having hierarchically organized architectures, various morphologies and functions based on fullerenes. By tuning the length and number of aliphatic chains on the derivatives as well as experimental conditions such as solvents, temperature, substrates for preparation of the assemblies, the assembled fullerenes showed various faces such as creating of many unique-shaped objects with controlled their dimensionality. For instance, nanowires and thin disks with single bilayer thickness in nanometer size, globular, fibrous, conical objects in mesoscopic (sub-micrometer) scale and flower-shaped and direction-controlled spiral objects in micrometer scale are obtained. As bulk states, thermotropic liquid crystals and room temperature (isotropic) liquid fullerenes are interestingly prepared from this molecular designs and showed not only their fluid natures and comparably high carrier mobility as fullerene-based organic-semiconductor phenomena. In addition, nano-carbon superhydrophobic surface with fractal morphology of the two-tier roughness on a nano- and microscopic scale was created from one of the supramolecular objects. The all of hierarchical supramolecular assemblies describing in this review is derived from fine-tuning intermolecular interactions of fullerene derivatives bearing long aliphatic chains.

  14. Hierarchical self-organization of cytoskeletal active networks

    CERN Document Server

    Gordon, Daniel; Keasar, Chen; Farago, Oded

    2012-01-01

    The structural reorganization of the actin cytoskeleton is facilitated through the action of motor proteins that crosslink the actin filaments and transport them relative to each other. Here, we present a combined experimental-computational study that probes the dynamic evolution of mixtures of actin filaments and clusters of myosin motors. While on small spatial and temporal scales the system behaves in a very noisy manner, on larger scales it evolves into several well distinct patterns such as bundles, asters, and networks. These patterns are characterized by junctions with high connectivity, whose formation is possible due to the organization of the motors in "oligoclusters" (intermediate-size aggregates). The simulations reveal that the self-organization process proceeds through a series of hierarchical steps, starting from local microscopic moves and ranging up to the macroscopic large scales where the steady-state structures are formed. Our results shed light into the mechanisms involved in processes li...

  15. Hierarchical organization of brain functional network during visual task

    CERN Document Server

    Zhuo, Zhao; Fu, Zhong-Qian; Zhang, Jie

    2011-01-01

    In this paper, the brain functional networks derived from high-resolution synchronous EEG time series during visual task are generated by calculating the phase synchronization among the time series. The hierarchical modular organizations of these networks are systematically investigated by the fast Girvan-Newman algorithm. At the same time, the spatially adjacent electrodes (corresponding to EEG channels) are clustered into functional groups based on anatomical parcellation of brain cortex, and this clustering information are compared to that of the functional network. The results show that the modular architectures of brain functional network are in coincidence with that from the anatomical structures over different levels of hierarchy, which suggests that population of neurons performing the same function excite and inhibit in identical rhythms. The structure-function relationship further reveals that the correlations among EEG time series in the same functional group are much stronger than those in differe...

  16. Auditory Temporal-Organization Abilities in School-Age Children with Peripheral Hearing Loss

    Science.gov (United States)

    Koravand, Amineh; Jutras, Benoit

    2013-01-01

    Purpose: The objective was to assess auditory sequential organization (ASO) ability in children with and without hearing loss. Method: Forty children 9 to 12 years old participated in the study: 12 with sensory hearing loss (HL), 12 with central auditory processing disorder (CAPD), and 16 with normal hearing. They performed an ASO task in which…

  17. Auditory Temporal-Organization Abilities in School-Age Children with Peripheral Hearing Loss

    Science.gov (United States)

    Koravand, Amineh; Jutras, Benoit

    2013-01-01

    Purpose: The objective was to assess auditory sequential organization (ASO) ability in children with and without hearing loss. Method: Forty children 9 to 12 years old participated in the study: 12 with sensory hearing loss (HL), 12 with central auditory processing disorder (CAPD), and 16 with normal hearing. They performed an ASO task in which…

  18. Modeling evolutionary dynamics of epigenetic mutations in hierarchically organized tumors.

    Directory of Open Access Journals (Sweden)

    Andrea Sottoriva

    2011-05-01

    Full Text Available The cancer stem cell (CSC concept is a highly debated topic in cancer research. While experimental evidence in favor of the cancer stem cell theory is apparently abundant, the results are often criticized as being difficult to interpret. An important reason for this is that most experimental data that support this model rely on transplantation studies. In this study we use a novel cellular Potts model to elucidate the dynamics of established malignancies that are driven by a small subset of CSCs. Our results demonstrate that epigenetic mutations that occur during mitosis display highly altered dynamics in CSC-driven malignancies compared to a classical, non-hierarchical model of growth. In particular, the heterogeneity observed in CSC-driven tumors is considerably higher. We speculate that this feature could be used in combination with epigenetic (methylation sequencing studies of human malignancies to prove or refute the CSC hypothesis in established tumors without the need for transplantation. Moreover our tumor growth simulations indicate that CSC-driven tumors display evolutionary features that can be considered beneficial during tumor progression. Besides an increased heterogeneity they also exhibit properties that allow the escape of clones from local fitness peaks. This leads to more aggressive phenotypes in the long run and makes the neoplasm more adaptable to stringent selective forces such as cancer treatment. Indeed when therapy is applied the clone landscape of the regrown tumor is more aggressive with respect to the primary tumor, whereas the classical model demonstrated similar patterns before and after therapy. Understanding these often counter-intuitive fundamental properties of (non-hierarchically organized malignancies is a crucial step in validating the CSC concept as well as providing insight into the therapeutical consequences of this model.

  19. Hierarchically Organized Iterative Solutions of the Evolution Equations in QCD

    CERN Document Server

    Jadach, S; Was, Z

    2007-01-01

    The task of Monte Carlo simulation of the evolution of the parton distributions in QCD and of constructing new parton shower Monte Carlo algorithms requires new way of organizing solutions of the QCD evolution equations, in which quark-gluon transitions on one hand and quark-quark or gluon-gluon transitions (pure gluonstrahlung) on the other hand, are treated separately and differently. This requires certain reorganization of the iterative solutions of the QCD evolution equations and leads to what we refer to as a hierarchic iterative solutions of the evolution equations. We present three formal derivations of such a solution. Results presented here are already used in the other recent works to formulate new MC algorithms for the parton-shower-like implementations of the QCD evolution equations. They are primarily of the non-Markovian type. However, such a solution can be used for the Markovian-type MCs as well. We also comment briefly on the relation of the presented formalism to similar methods used in othe...

  20. The auditory cortex of the bat Phyllostomus discolor: Localization and organization of basic response properties.

    Science.gov (United States)

    Hoffmann, Susanne; Firzlaff, Uwe; Radtke-Schuller, Susanne; Schwellnus, Britta; Schuller, Gerd

    2008-07-14

    The mammalian auditory cortex can be subdivided into various fields characterized by neurophysiological and neuroarchitectural properties and by connections with different nuclei of the thalamus. Besides the primary auditory cortex, echolocating bats have cortical fields for the processing of temporal and spectral features of the echolocation pulses. This paper reports on location, neuroarchitecture and basic functional organization of the auditory cortex of the microchiropteran bat Phyllostomus discolor (family: Phyllostomidae). The auditory cortical area of P. discolor is located at parieto-temporal portions of the neocortex. It covers a rostro-caudal range of about 4800 mum and a medio-lateral distance of about 7000 mum on the flattened cortical surface. The auditory cortices of ten adult P. discolor were electrophysiologically mapped in detail. Responses of 849 units (single neurons and neuronal clusters up to three neurons) to pure tone stimulation were recorded extracellularly. Cortical units were characterized and classified depending on their response properties such as best frequency, auditory threshold, first spike latency, response duration, width and shape of the frequency response area and binaural interactions. Based on neurophysiological and neuroanatomical criteria, the auditory cortex of P. discolor could be subdivided into anterior and posterior ventral fields and anterior and posterior dorsal fields. The representation of response properties within the different auditory cortical fields was analyzed in detail. The two ventral fields were distinguished by their tonotopic organization with opposing frequency gradients. The dorsal cortical fields were not tonotopically organized but contained neurons that were responsive to high frequencies only. The auditory cortex of P. discolor resembles the auditory cortex of other phyllostomid bats in size and basic functional organization. The tonotopically organized posterior ventral field might represent the

  1. The auditory cortex of the bat Phyllostomus discolor: Localization and organization of basic response properties

    Directory of Open Access Journals (Sweden)

    Schwellnus Britta

    2008-07-01

    Full Text Available Abstract Background The mammalian auditory cortex can be subdivided into various fields characterized by neurophysiological and neuroarchitectural properties and by connections with different nuclei of the thalamus. Besides the primary auditory cortex, echolocating bats have cortical fields for the processing of temporal and spectral features of the echolocation pulses. This paper reports on location, neuroarchitecture and basic functional organization of the auditory cortex of the microchiropteran bat Phyllostomus discolor (family: Phyllostomidae. Results The auditory cortical area of P. discolor is located at parieto-temporal portions of the neocortex. It covers a rostro-caudal range of about 4800 μm and a medio-lateral distance of about 7000 μm on the flattened cortical surface. The auditory cortices of ten adult P. discolor were electrophysiologically mapped in detail. Responses of 849 units (single neurons and neuronal clusters up to three neurons to pure tone stimulation were recorded extracellularly. Cortical units were characterized and classified depending on their response properties such as best frequency, auditory threshold, first spike latency, response duration, width and shape of the frequency response area and binaural interactions. Based on neurophysiological and neuroanatomical criteria, the auditory cortex of P. discolor could be subdivided into anterior and posterior ventral fields and anterior and posterior dorsal fields. The representation of response properties within the different auditory cortical fields was analyzed in detail. The two ventral fields were distinguished by their tonotopic organization with opposing frequency gradients. The dorsal cortical fields were not tonotopically organized but contained neurons that were responsive to high frequencies only. Conclusion The auditory cortex of P. discolor resembles the auditory cortex of other phyllostomid bats in size and basic functional organization. The

  2. Discovery of a lipid synthesising organ in the auditory system of an insect.

    Science.gov (United States)

    Lomas, Kathryn F; Greenwood, David R; Windmill, James F C; Jackson, Joseph C; Corfield, Jeremy; Parsons, Stuart

    2012-01-01

    Weta possess typical Ensifera ears. Each ear comprises three functional parts: two equally sized tympanal membranes, an underlying system of modified tracheal chambers, and the auditory sensory organ, the crista acustica. This organ sits within an enclosed fluid-filled channel-previously presumed to be hemolymph. The role this channel plays in insect hearing is unknown. We discovered that the fluid within the channel is not actually hemolymph, but a medium composed principally of lipid from a new class. Three-dimensional imaging of this lipid channel revealed a previously undescribed tissue structure within the channel, which we refer to as the olivarius organ. Investigations into the function of the olivarius reveal de novo lipid synthesis indicating that it is producing these lipids in situ from acetate. The auditory role of this lipid channel was investigated using Laser Doppler vibrometry of the tympanal membrane, which shows that the displacement of the membrane is significantly increased when the lipid is removed from the auditory system. Neural sensitivity of the system, however, decreased upon removal of the lipid-a surprising result considering that in a typical auditory system both the mechanical and auditory sensitivity are positively correlated. These two results coupled with 3D modelling of the auditory system lead us to hypothesize a model for weta audition, relying strongly on the presence of the lipid channel. This is the first instance of lipids being associated with an auditory system outside of the Odentocete cetaceans, demonstrating convergence for the use of lipids in hearing.

  3. Similar structural dimensions in bushcricket auditory organs in spite of different foreleg size: consequences for auditory tuning.

    Science.gov (United States)

    Rössler, W; Kalmring, K

    1994-11-01

    The bushcricket species Decticus albifrons, Decticus verrucivorus and Pholidoptera griseoaptera (Tettigoniidae) belong to the same subfamily (Decticinae) but differ significantly in body size. In spite of the great differences in the dimensions of the forelegs, where the auditory organs are located, the most sensitive range of the hearing threshold lies between 6 and 25 kHz in each case. Only in the frequency range from 2 to 5 kHz and above 25 kHz, significant differences are present. The anatomy of the auditory receptor organs was compared quantitatively, using the techniques of semi-thin sectioning and computer-guided morphometry. The overall number of scolopidia and the length of the crista acustica differs in the three species, but the relative distribution of scolopidia along the crista acustica is very similar. Additionally, the scolopidia and their attachment structures (tectorial membrane, dorsal tracheal wall, cap cells) are of equal size at equivalent relative positions along the crista acustica. The results indicate that the constant relations and dimensions of corresponding structures within the cristae acusticae of the three species are responsible for the similarities in the tuning of the auditory thresholds.

  4. Hierarchic Theory of Complex Systems (biosystems, colloids) self-organization and osmosis

    CERN Document Server

    Kaivarainen, A

    2000-01-01

    Summary of 'Hierarchic theory of condensed matter' Introduction 1. Protein domain mesoscopic organization 2. Quantum background of lipid domain organization in biomembranes 3. Hierarchic approach to theory of solutions and colloid systems 4. Distant solvent-mediated interaction between macromolecules 5. Spatial self-organization in the water-macromolecular systems 6. Properties of [bisolvent - polymer system] 7. Osmosis and solvent activity. Traditional and mesoscopic approach

  5. Predictability of extremes in non-linear hierarchically organized systems

    Science.gov (United States)

    Kossobokov, V. G.; Soloviev, A.

    2011-12-01

    Understanding the complexity of non-linear dynamics of hierarchically organized systems progresses to new approaches in assessing hazard and risk of the extreme catastrophic events. In particular, a series of interrelated step-by-step studies of seismic process along with its non-stationary though self-organized behaviors, has led already to reproducible intermediate-term middle-range earthquake forecast/prediction technique that has passed control in forward real-time applications during the last two decades. The observed seismic dynamics prior to and after many mega, great, major, and strong earthquakes demonstrate common features of predictability and diverse behavior in course durable phase transitions in complex hierarchical non-linear system of blocks-and-faults of the Earth lithosphere. The confirmed fractal nature of earthquakes and their distribution in space and time implies that many traditional estimations of seismic hazard (from term-less to short-term ones) are usually based on erroneous assumptions of easy tractable analytical models, which leads to widespread practice of their deceptive application. The consequences of underestimation of seismic hazard propagate non-linearly into inflicted underestimation of risk and, eventually, into unexpected societal losses due to earthquakes and associated phenomena (i.e., collapse of buildings, landslides, tsunamis, liquefaction, etc.). The studies aimed at forecast/prediction of extreme events (interpreted as critical transitions) in geophysical and socio-economical systems include: (i) large earthquakes in geophysical systems of the lithosphere blocks-and-faults, (ii) starts and ends of economic recessions, (iii) episodes of a sharp increase in the unemployment rate, (iv) surge of the homicides in socio-economic systems. These studies are based on a heuristic search of phenomena preceding critical transitions and application of methodologies of pattern recognition of infrequent events. Any study of rare

  6. Hierarchical organization of segmentation in non-functional action sequences

    DEFF Research Database (Denmark)

    Nielbo, Kristoffer Laigaard; Schjødt, Uffe; Sørensen, Jesper

    2013-01-01

    Both folk and scientific taxonomies of behavior distinguish between instrumental and ritual behavior. Recent studies indicate that behaviors dominated by ritual features tend to increase cognitive load by focusing attentional and working memory resources on low-level perceptual details and psycho......-physics. In contrast to the general consensus in anthropology and the study of religion, one study did not find any modulation effect of expectations (e.g., cultural information or priors) on cognitive load. It has, therefore, been suggested that the increase reflects a perceptual mechanism that drives categorization...... of ritual behavior. The present study investigated how an increase in cognitive load elicited by ritual behavior can influence hierarchically-related representations of actions and if expectation can modulate such hierarchical action representations. The study found that hierarchical alignment during...

  7. Dynamics and thermodynamics in hierarchically organized systems applications in physics, biology and economics

    CERN Document Server

    Auger, P

    2013-01-01

    One of the most fundamental and efficient ways of conceptualizing complex systems is to organize them hierarchically. A hierarchically organized system is represented by a network of interconnected subsystems, each of which has its own network of subsystems, and so on, until some elementary subsystems are reached that are not further decomposed. This original and important book proposes a general mathematical theory of a hierarchical system and shows how it can be applied to very different topics such as physics (Hamiltonian systems), biology (coupling the molecular and the cellular levels), e

  8. The evolutionary origin of auditory receptors in Tettigonioidea: the complex tibial organ of Schizodactylidae.

    Science.gov (United States)

    Strauss, Johannes; Lakes-Harlan, Reinhard

    2009-01-01

    Audition in insects is of polyphyletic origin. Tympanal ears derived from proprioceptive or vibratory receptor organs, but many questions of the evolution of insect auditory systems are still open. Despite the rather typical bauplan of the insect body, e.g., with a fixed number of segments, tympanal ears evolved at very different places, but only ensiferans have ears at the foreleg tibia, located in the tibial organ. The homology and monophyly of ensiferan ears is controversial, and no precursor organ was unambiguously identified for auditory receptors. The latter can only be identified by comparative study of recent atympanate taxa. These atympanate taxa are poorly investigated. In this paper, we report the neuroanatomy of the tibial organ of Comicus calcaris (Irish 1986), an atympanate Schizodactylid (splay-footed cricket). This representative of a Gondwana relict group has a tripartite sensory organ, homologous to tettigoniid ears. A comparison with morphology-based cladistic phylogeny indicates that the tripartite neuronal organization present in the majority of Tettigonioidea presumably preceded evolution of a hearing sense in the Tettigonioidea. Furthermore, the absence of a tripartite organ in Grylloidea argues against a monophyletic origin and homology of the cricket and katydid ears. The tracheal attachment of sensory neurons typical for ears of Tettigonioidea is present in C. calcaris and may have facilitated cooption for auditory function. The functional auditory organ was presumably formed in evolution by successive non-neural modifications of trachea and tympana. This first investigation of the neuroanatomy of Schizodactylidae suggests a non-auditory chordotonal organ as the precursor for auditory receptors of related tympanate taxa and adds evidence for the phylogenetic position of the group.

  9. Bedside Evaluation of the Functional Organization of the Auditory Cortex in Patients with Disorders of Consciousness.

    Science.gov (United States)

    Henriques, Julie; Pazart, Lionel; Grigoryeva, Lyudmila; Muzard, Emelyne; Beaussant, Yvan; Haffen, Emmanuel; Moulin, Thierry; Aubry, Régis; Ortega, Juan-Pablo; Gabriel, Damien

    2016-01-01

    To measure the level of residual cognitive function in patients with disorders of consciousness, the use of electrophysiological and neuroimaging protocols of increasing complexity is recommended. This work presents an EEG-based method capable of assessing at an individual level the integrity of the auditory cortex at the bedside of patients and can be seen as the first cortical stage of this hierarchical approach. The method is based on two features: first, the possibility of automatically detecting the presence of a N100 wave and second, in showing evidence of frequency processing in the auditory cortex with a machine learning based classification of the EEG signals associated with different frequencies and auditory stimulation modalities. In the control group of twelve healthy volunteers, cortical frequency processing was clearly demonstrated. EEG recordings from two patients with disorders of consciousness showed evidence of partially preserved cortical processing in the first patient and none in the second patient. From these results, it appears that the classification method presented here reliably detects signal differences in the encoding of frequencies and is a useful tool in the evaluation of the integrity of the auditory cortex. Even though the classification method presented in this work was designed for patients with disorders of consciousness, it can also be applied to other pathological populations.

  10. Evoked response audiometry used in testing auditory organs of miners

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, T.; Klepacki, J.; Wagstyl, R.

    1980-01-01

    The evoked response audiometry method of testing hearing loss is presented and the results of comparative studies using subjective tonal audiometry and evoked response audiometry in tests of 56 healthy men with good hearing are discussed. The men were divided into three groups according to age and place of work: work place without increased noise; work place with noise and vibrations (at drilling machines); work place with noise and shocks (work at excavators in surface coal mines). The ERA-MKII audiometer produced by the Medelec-Amplaid firm was used. Audiometric threshhold curves for the three groups of tested men are given. At frequencies of 500, 1000 and 4000 Hz mean objective auditory threshhold was shifted by 4-9.5 dB in comparison to the subjective auditory threshold. (21 refs.) (In Polish)

  11. Tonotopic organization of auditory receptors of the bushcricket pholidoptera griseoaptera (Tettigoniidae, decticinae)

    Science.gov (United States)

    Stolting; Stumpner

    1998-11-01

    The peripheral and central tonotopy of auditory receptors of the bushcricket Pholidoptera griseoaptera is described. Out of 24 auditory receptor cells of the crista acustica 18 were identified by single-cell recordings in the prothoracic ganglion and complete staining with neurobiotin. Proximal receptor cells of the crista acustica were most sensitive to 6 kHz, with medial cells being sensitive to 20-30 kHz, whereas distal cells were most sensitive to frequencies higher than 50 kHz. Projection areas within the auditory neuropile in the prothoracic ganglion were to- notopically arranged. Proximal cells projected anteriorly, medial cells ventrally and posteriorly, and distal cells to more dorsal regions. Identified receptor cells revealed an interindividual variability of tuning and central projections. Receptor cells from the intermediate organ of a bushcricket were identified for the first time. Receptors of the distal intermediate organ were broadly tuned and less sensitive than those of the crista acustica. Receptor cells of the proximal intermediate organ were most sensitive to frequencies below 10 kHz. They projected in anterior portions of the auditory neuropile, whereas cells of the distal intermediate organ had terminations spread over almost the whole auditory neuropile.

  12. Hierarchic Theory of Complex Systems (biosystems, colloids): self-organization & osmos

    OpenAIRE

    Kaivarainen, Alex

    2000-01-01

    1. Protein domain mesoscopic organization 2. Quantum background of lipid domain organization in biomembranes 3. Hierarchic approach to theory of solutions and colloid systems 4. Distant solvent-mediated interaction between macromolecules 5. Spatial self-organization in the water-macromolecular systems 6. Properties of [bisolvent - polymer system] 7. Osmosis and solvent activity. Traditional and mesoscopic approach

  13. Hierarchical supramolecules and organization using boronic acid building blocks.

    Science.gov (United States)

    Kubo, Yuji; Nishiyabu, Ryuhei; James, Tony D

    2015-02-07

    Current progress on hierarchical supramolecules using boronic acids has been highlighted in this feature article. Boronic acids can participate in "click reactions" with diols and their congeners with dynamic covalent functionality. By comprehensively exploring versatile sequential boronate esterification linkages between plural boronic acid-appended molecules and multiple hydroxyl counterparts, not only versatile supramolecular polymers but also structurally well-defined network nanostructures have been developed. In addition orthogonal interactions such as dative bonds of the boron center with Lewis bases have led to the formation of hierarchical nano/microstructures. Boronate systems have the potential to be used as materials for smart gels, chemosensors, active architectures for electronics, heterogeneous catalysts, chemical-stimulus responsive systems for drug delivery, etc. Here, we fully discuss the feasibility of the structure-directing ability of boronic acids from the standpoint of the generation of new smart materials.

  14. Measuring efficiency of a hierarchical organization with fuzzy DEA method

    OpenAIRE

    LUBAN Florica

    2009-01-01

    The paper analyses how the data envelopment analysis (DEA) and fuzzy set theory can be used to measure and evaluate the efficiency of a hierarchical system with n decision making units and a coordinating unit. It is presented a model for determining the of activity levels of decision making units so as to achieve both fuzzy objectives of achieving global target levels of coordination unit on the inputs and outputs and individual target levels of decision making units, and then some methods to...

  15. Hierarchical self-organization of non-cooperating individuals

    OpenAIRE

    Tamás Nepusz; Tamás Vicsek

    2013-01-01

    Hierarchy is one of the most conspicuous features of numerous natural, technological and social systems. The underlying structures are typically complex and their most relevant organizational principle is the ordering of the ties among the units they are made of according to a network displaying hierarchical features. In spite of the abundant presence of hierarchy no quantitative theoretical interpretation of the origins of a multi-level, knowledge-based social network exists. Here we introdu...

  16. Discovery of a lipid synthesising organ in the auditory system of an insect.

    Directory of Open Access Journals (Sweden)

    Kathryn F Lomas

    Full Text Available Weta possess typical Ensifera ears. Each ear comprises three functional parts: two equally sized tympanal membranes, an underlying system of modified tracheal chambers, and the auditory sensory organ, the crista acustica. This organ sits within an enclosed fluid-filled channel-previously presumed to be hemolymph. The role this channel plays in insect hearing is unknown. We discovered that the fluid within the channel is not actually hemolymph, but a medium composed principally of lipid from a new class. Three-dimensional imaging of this lipid channel revealed a previously undescribed tissue structure within the channel, which we refer to as the olivarius organ. Investigations into the function of the olivarius reveal de novo lipid synthesis indicating that it is producing these lipids in situ from acetate. The auditory role of this lipid channel was investigated using Laser Doppler vibrometry of the tympanal membrane, which shows that the displacement of the membrane is significantly increased when the lipid is removed from the auditory system. Neural sensitivity of the system, however, decreased upon removal of the lipid-a surprising result considering that in a typical auditory system both the mechanical and auditory sensitivity are positively correlated. These two results coupled with 3D modelling of the auditory system lead us to hypothesize a model for weta audition, relying strongly on the presence of the lipid channel. This is the first instance of lipids being associated with an auditory system outside of the Odentocete cetaceans, demonstrating convergence for the use of lipids in hearing.

  17. Multiple dynamical time-scales in networks with hierarchically nested modular organization

    Indian Academy of Sciences (India)

    Sitabhra Sinha; Swarup Poria

    2011-11-01

    Many natural and engineered complex networks have intricate mesoscopic organization, e.g., the clustering of the constituent nodes into several communities or modules. Often, such modularity is manifested at several different hierarchical levels, where the clusters defined at one level appear as elementary entities at the next higher level. Using a simple model of a hierarchical modular network, we show that such a topological structure gives rise to characteristic time-scale separation between dynamics occurring at different levels of the hierarchy. This generalizes our earlier result for simple modular networks, where fast intramodular and slow intermodular processes were clearly distinguished. Investigating the process of synchronization of oscillators in a hierarchical modular network, we show the existence of as many distinct time-scales as there are hierarchical levels in the system. This suggests a possible functional role of such mesoscopic organization principle in natural systems, viz., in the dynamical separation of events occurring at different spatial scales.

  18. Preparation of hierarchically organized calcium phosphate–organic polymer composites by calcification of hydrogel

    Directory of Open Access Journals (Sweden)

    Kozue Furuichi, Yuya Oaki, Hirofumi Ichimiya, Jun Komotori and Hiroaki Imai

    2006-01-01

    Full Text Available A novel type of calcium phosphate–organic polymer composite having a hierarchical structure was prepared by calcification of a poly(acrylic acid hydrogel. Macroscopically, an organic gel containing phosphate ions was transformed into an opaque solid material by diffusion of calcium ions. We observed the formation of micrometer-scale layered structures consisting of nanoscale crystals of hydroxylapatite (HAp in the opaque products. The laminated architecture resulting from the periodic precipitation of calcium phosphate varied with the reaction conditions, such as the concentrations of the precursor ions and the density of the gel. The nanoscopic structure of HAp crystals was modified by the addition of gelatin to the polymer matrix.

  19. Broca's area processes the hierarchical organization of observed action.

    Science.gov (United States)

    Wakita, Masumi

    2013-01-01

    Broca's area has been suggested as the area responsible for the domain-general hierarchical processing of language and music. Although meaningful action shares a common hierarchical structure with language and music, the role of Broca's area in this domain remains controversial. To address the involvement of Broca's area in the processing action hierarchy, the activation of Broca's area was measured using near-infrared spectroscopy. Measurements were taken while participants watched silent movies that featured hand movements playing familiar and unfamiliar melodies. The unfamiliar melodies were reversed versions of the familiar melodies. Additionally, to investigate the effect of a motor experience on the activation of Broca's area, the participants were divided into well-trained and less-trained groups. The results showed that Broca's area in the well-trained participants demonstrated a significantly larger activation in response to the hand motion when an unfamiliar melody was played than when a familiar melody was played. However, Broca's area in the less-trained participants did not show a contrast between conditions despite identical abilities of the two participant groups to identify the melodies by watching key pressing actions. These results are consistent with previous findings that Broca's area exhibits increased activation in response to grammatically violated sentences and musically deviated chord progressions as well as the finding that this region does not represent the processing of grammatical structure in less-proficient foreign language speakers. Thus, the current study suggests that Broca's area represents action hierarchy and that sufficiently long motor training is necessary for it to become sensitive to motor syntax. Therefore, the notion that hierarchical processing in Broca's area is a common function shared between language and music may help to explain the role of Broca's area in action perception.

  20. Interconnected growing self-organizing maps for auditory and semantic acquisition modeling

    Directory of Open Access Journals (Sweden)

    Mengxue eCao

    2014-03-01

    Full Text Available Based on the incremental nature of knowledge acquisition, in this study we propose a growing self-organizing neural network approach for modeling the acquisition of auditory and semantic categories. We introduce an Interconnected Growing Self-Organizing Maps (I-GSOM algorithm, which takes associations between auditory information and semantic information into consideration, in this paper. Direct phonetic--semantic association is simulated in order to model the language acquisition in early phases, such as the babbling and imitation stages, in which no phonological representations exist. Based on the I-GSOM algorithm, we conducted experiments using paired acoustic and semantic training data. We use a cyclical reinforcing and reviewing training procedure to model the teaching and learning process between children and their communication partners; a reinforcing-by-link training procedure and a link-forgetting procedure are introduced to model the acquisition of associative relations between auditory and semantic information. Experimental results indicate that (1 I-GSOM has good ability to learn auditory and semantic categories presented within the training data; (2 clear auditory and semantic boundaries can be found in the network representation; (3 cyclical reinforcing and reviewing training leads to a detailed categorization as well as to a detailed clustering, while keeping the clusters that have already been learned and the network structure that has already been developed stable; and (4 reinforcing-by-link training leads to well-perceived auditory--semantic associations. Our I-GSOM model suggests that it is important to associate auditory information with semantic information during language acquisition. Despite its high level of abstraction, our I-GSOM approach can be interpreted as a biologically-inspired neurocomputational model.

  1. Psychological autonomy and hierarchical relatedness as organizers of developmental pathways.

    Science.gov (United States)

    Keller, Heidi

    2016-01-19

    The definition of self and others can be regarded as embodying the two dimensions of autonomy and relatedness. Autonomy and relatedness are two basic human needs and cultural constructs at the same time. This implies that they may be differently defined yet remain equally important. The respective understanding of autonomy and relatedness is socialized during the everyday experiences of daily life routines from birth on. In this paper, two developmental pathways are portrayed that emphasize different conceptions of autonomy and relatedness that are adaptive in two different environmental contexts with very different affordances and constraints. Western middle-class children are socialized towards psychological autonomy, i.e. the primacy of own intentions, wishes, individual preferences and emotions affording a definition of relatedness as psychological negotiable construct. Non-Western subsistence farmer children are socialized towards hierarchical relatedness, i.e. positioning oneself into the hierarchical structure of a communal system affording a definition of autonomy as action oriented, based on responsibility and obligations. Infancy can be regarded as a cultural lens through which to study the different socialization agendas. Parenting strategies that aim at supporting these different socialization goals in German and Euro-American parents on the one hand and Nso farmers from North Western Cameroon on the other hand are described. It is concluded that different pathways need to be considered in order to understand human psychology from a global perspective. © 2015 The Author(s).

  2. Shape Controlled Hierarchical Porous Hydrophobic/Oleophilic Metal-Organic Nanofibrous Gel Composites for Oil Adsorption.

    Science.gov (United States)

    Jayaramulu, Kolleboyina; Geyer, Florian; Petr, Martin; Zboril, Radek; Vollmer, Doris; Fischer, Roland A

    2017-03-01

    A versatile and facile synthetic route toward a ultralight hierarchical poroushybrid composed of metal-organic gels and fluorinated graphene oxide is reported. The composite gels show excellent absorbency of oil and various organic solvents due to their prominent meso/macropores, notable hydrophobicity, and superoleophilicity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Mapping the Tonotopic Organization in Human Auditory Cortex with Minimally Salient Acoustic Stimulation

    NARCIS (Netherlands)

    Langers, Dave R. M.; van Dijk, Pim

    2012-01-01

    Despite numerous neuroimaging studies, the tonotopic organization in human auditory cortex is not yet unambiguously established. In this functional magnetic resonance imaging study, 20 subjects were presented with low-level task-irrelevant tones to avoid spread of cortical activation. Data-driven an

  4. Hierarchical Helical Order in the Twisted Growth of Plant Organs

    Science.gov (United States)

    Wada, Hirofumi

    2012-09-01

    The molecular and cellular basis of left-right asymmetry in plant morphogenesis is a fundamental issue in biology. A rapidly elongating root or hypocotyl of twisting mutants of Arabidopsis thaliana exhibits a helical growth with a handedness opposite to that of the underlying cortical microtubule arrays in epidermal cells. However, how such a hierarchical helical order emerges is currently unknown. We propose a model for investigating macroscopic chiral asymmetry in Arabidopsis mutants. Our elastic model suggests that the helical pattern observed is a direct consequence of the simultaneous presence of anisotropic growth and tilting of cortical microtubule arrays. We predict that the root helical pitch angle is a function of the microtubule helical angle and elastic moduli of the tissues. The proposed model is versatile and is potentially important for other biological systems ranging from protein fibrous structures to tree trunks.

  5. Spatially Resolved Monitoring of Drying of Hierarchical Porous Organic Networks.

    Science.gov (United States)

    Velasco, Manuel Isaac; Silletta, Emilia V; Gomez, Cesar G; Strumia, Miriam C; Stapf, Siegfried; Monti, Gustavo Alberto; Mattea, Carlos; Acosta, Rodolfo H

    2016-03-01

    Evaporation kinetics of water confined in hierarchal polymeric porous media is studied by low field nuclear magnetic resonance (NMR). Systems synthesized with various degrees of cross-linker density render networks with similar pore sizes but different response when soaked with water. Polymeric networks with low percentage of cross-linker can undergo swelling, which affects the porosity as well as the drying kinetics. The drying process is monitored macroscopically by single-sided NMR, with spatial resolution of 100 μm, while microscopic information is obtained by measurements of spin-spin relaxation times (T2). Transition from a funicular to a pendular regime, where hydraulic connectivity is lost and the capillary flow cannot compensate for the surface evaporation, can be observed from inspection of the water content in different sample layers. Relaxation measurements indicate that even when the larger pore structures are depleted of water, capillary flow occurs through smaller voids.

  6. Proton Conduction in Sulfonated Organic-Inorganic Hybrid Monoliths with Hierarchical Pore Structure.

    Science.gov (United States)

    von der Lehr, Martin; Seidler, Christopher F; Taffa, Dereje H; Wark, Michael; Smarsly, Bernd M; Marschall, Roland

    2016-09-28

    Porous organic-inorganic hybrid monoliths with hierarchical porosity exhibiting macro- and mesopores are prepared via sol-gel process under variation of the mesopore size. Organic moieties in the pore walls are incorporated by substituting up to 10% of the silicon precursor tetramethylorthosilicate with bisilylated benzene molecules. After functionalization with sulfonic acid groups, the resulting sulfonated hybrid monoliths featuring a bimodal pore structure are investigated regarding proton conduction depending on temperature and relative humidity. The hierarchical pore system and controlled mesopore design turn out to be crucial for sulfonation and proton conduction. These sulfonated hybrid hierarchical monoliths containing only 10% organic precursor exhibit higher proton conduction at different relative humidities than sulfonated periodic mesoporous organosilica made of 100% bisilylated precursors exhibiting solely mesopores, even with a lower concentration of sulfonic acid groups.

  7. Multilevel compression of random walks on networks reveals hierarchical organization in large integrated systems

    CERN Document Server

    Rosvall, M

    2010-01-01

    To comprehend the hierarchical organization of large integrated systems, we introduce the hierarchical map equation that reveals multilevel structures in networks. In this information-theoretic approach, we exploit the duality between compression and pattern detection; by compressing a description of a random walker as a proxy for real flow on a network, we find regularities in the network that induce this system-wide flow. Finding the shortest multilevel description of the random walker therefore gives us the best hierarchical clustering of the network, the optimal number of levels and modular partition at each level, with respect to the dynamics on the network. With a novel search algorithm, we extract and illustrate the rich multilevel organization of several large social and biological networks. For example, from the global air traffic network we uncover countries and continents, and from the pattern of scientific communication we reveal more than 100 scientific fields organized in four major disciplines:...

  8. Memory Stacking in Hierarchical Networks.

    Science.gov (United States)

    Westö, Johan; May, Patrick J C; Tiitinen, Hannu

    2016-02-01

    Robust representations of sounds with a complex spectrotemporal structure are thought to emerge in hierarchically organized auditory cortex, but the computational advantage of this hierarchy remains unknown. Here, we used computational models to study how such hierarchical structures affect temporal binding in neural networks. We equipped individual units in different types of feedforward networks with local memory mechanisms storing recent inputs and observed how this affected the ability of the networks to process stimuli context dependently. Our findings illustrate that these local memories stack up in hierarchical structures and hence allow network units to exhibit selectivity to spectral sequences longer than the time spans of the local memories. We also illustrate that short-term synaptic plasticity is a potential local memory mechanism within the auditory cortex, and we show that it can bring robustness to context dependence against variation in the temporal rate of stimuli, while introducing nonlinearities to response profiles that are not well captured by standard linear spectrotemporal receptive field models. The results therefore indicate that short-term synaptic plasticity might provide hierarchically structured auditory cortex with computational capabilities important for robust representations of spectrotemporal patterns.

  9. Sustained activity in hierarchical modular neural networks: self-organized criticality and oscillations

    Directory of Open Access Journals (Sweden)

    Sheng-Jun Wang

    2011-06-01

    Full Text Available Cerebral cortical brain networks possess a number of conspicuous features of structure and dynamics. First, these networks have an intricate, non-random organization. They are structured in a hierarchical modular fashion, from large-scale regions of the whole brain, via cortical areas and area subcompartments organized as structural and functional maps to cortical columns, and finally circuits made up of individual neurons. Second, the networks display self-organized sustained activity, which is persistent in the absence of external stimuli. At the systems level, such activity is characterized by complex rhythmical oscillations over a broadband background, while at the cellular level, neuronal discharges have been observed to display avalanches, indicating that cortical networks are at the state of self-organized criticality. We explored the relationship between hierarchical neural network organization and sustained dynamics using large-scale network modeling. It was shown that sparse random networks with balanced excitation and inhibition can sustain neural activity without external stimulation. We find that a hierarchical modular architecture can generate sustained activity better than random networks. Moreover, the system can simultaneously support rhythmical oscillations and self-organized criticality, which are not present in the respective random networks. The underlying mechanism is that each dense module cannot sustain activity on its own, but displays self-organized criticality in the presence of weak perturbations. The hierarchical modular networks provide the coupling among subsystems with self-organized criticality. These results imply that the hierarchical modular architecture of cortical networks plays an important role in shaping the ongoing spontaneous activity of the brain, potentially allowing the system to take advantage of both the sensitivityof critical state and predictability and timing of oscillations for efficient

  10. Organization of the auditory brainstem in a lizard, Gekko gecko. I. Auditory nerve, cochlear nuclei, and superior olivary nuclei

    DEFF Research Database (Denmark)

    Tang, Y. Z.; Christensen-Dalsgaard, J.; Carr, C. E.

    2012-01-01

    We used tract tracing to reveal the connections of the auditory brainstem in the Tokay gecko (Gekko gecko). The auditory nerve has two divisions, a rostroventrally directed projection of mid- to high best-frequency fibers to the nucleus angularis (NA) and a more dorsal and caudal projection of lo...... of auditory connections in lizards and archosaurs but also different processing of low- and high-frequency information in the brainstem. J. Comp. Neurol. 520:17841799, 2012. (C) 2011 Wiley Periodicals, Inc...

  11. Hierarchical organization and performance inequality: Evidence from professional cycling

    NARCIS (Netherlands)

    Candelon, B.; Dupuy, A.

    This article proposes an equilibrium theory of the organization of work in an economy with an implicit market for productive time. In this market, agents buy or sell productive time. This implicit market gives rise to the formation of teams, organized in hierarchies with one leader (buyer) at the

  12. Multi-Organ Contribution to the Metabolic Plasma Profile Using Hierarchical Modelling.

    Directory of Open Access Journals (Sweden)

    Frida Torell

    Full Text Available Hierarchical modelling was applied in order to identify the organs that contribute to the levels of metabolites in plasma. Plasma and organ samples from gut, kidney, liver, muscle and pancreas were obtained from mice. The samples were analysed using gas chromatography time-of-flight mass spectrometry (GC TOF-MS at the Swedish Metabolomics centre, Umeå University, Sweden. The multivariate analysis was performed by means of principal component analysis (PCA and orthogonal projections to latent structures (OPLS. The main goal of this study was to investigate how each organ contributes to the metabolic plasma profile. This was performed using hierarchical modelling. Each organ was found to have a unique metabolic profile. The hierarchical modelling showed that the gut, kidney and liver demonstrated the greatest contribution to the metabolic pattern of plasma. For example, we found that metabolites were absorbed in the gut and transported to the plasma. The kidneys excrete branched chain amino acids (BCAAs and fatty acids are transported in the plasma to the muscles and liver. Lactic acid was also found to be transported from the pancreas to plasma. The results indicated that hierarchical modelling can be utilized to identify the organ contribution of unknown metabolites to the metabolic profile of plasma.

  13. Hierarchical Organization of Organic Dyes and Protein Cages into Photoactive Crystals.

    Science.gov (United States)

    Mikkilä, Joona; Anaya-Plaza, Eduardo; Liljeström, Ville; Caston, Jose R; Torres, Tomas; Escosura, Andrés de la; Kostiainen, Mauri A

    2016-01-26

    Phthalocyanines (Pc) are non-natural organic dyes with wide and deep impact in materials science, based on their intense absorption at the near-infrared (NIR), long-lived fluorescence and high singlet oxygen ((1)O2) quantum yields. However, Pcs tend to stack in buffer solutions, losing their ability to generate singlet oxygen, which limits their scope of application. Furthermore, Pcs are challenging to organize in crystalline structures. Protein cages, on the other hand, are very promising biological building blocks that can be used to organize different materials into crystalline nanostructures. Here, we combine both kinds of components into photoactive biohybrid crystals. Toward this end, a hierarchical organization process has been designed in which (a) a supramolecular complex is formed between octacationic zinc Pc (1) and a tetraanionic pyrene (2) derivatives, driven by electrostatic and π-π interactions, and (b) the resulting tetracationic complex acts as a molecular glue that binds to the outer surface anionic patches of the apoferritin (aFt) protein cage, inducing cocrystallization. The obtained ternary face-centered cubic (fcc) packed cocrystals, with diameters up to 100 μm, retain the optical properties of the pristine dye molecules, such as fluorescence at 695 nm and efficient light-induced (1)O2 production. Considering that (1)O2 is utilized in important technologies such as photodynamic therapy (PDT), water treatments, diagnostic arrays and as an oxidant in organic synthesis, our results demonstrate a powerful methodology to create functional biohybrid systems with unprecedented long-range order. This approach should greatly aid the development of nanotechnology and biomedicine.

  14. Hierarchical Recursive Organization and the Free Energy Principle: From Biological Self-Organization to the Psychoanalytic Mind

    Directory of Open Access Journals (Sweden)

    Patrick Connolly

    2017-09-01

    Full Text Available The present paper argues that a systems theory epistemology (and particularly the notion of hierarchical recursive organization provides the critical theoretical context within which the significance of Friston's (2010a Free Energy Principle (FEP for both evolution and psychoanalysis is best understood. Within this perspective, the FEP occupies a particular level of the hierarchical organization of the organism, which is the level of biological self-organization. This form of biological self-organization is in turn understood as foundational and pervasive to the higher levels of organization of the human organism that are of interest to both neuroscience as well as psychoanalysis. Consequently, central psychoanalytic claims should be restated, in order to be located in their proper place within a hierarchical recursive organization of the (situated organism. In light of the FEP the realization of the psychoanalytic mind by the brain should be seen in terms of the evolution of different levels of systematic organization where the concepts of psychoanalysis describe a level of hierarchical recursive organization superordinate to that of biological self-organization and the FEP. The implication of this formulation is that while “psychoanalytic” mental processes are fundamentally subject to the FEP, they nonetheless also add their own principles of process over and above that of the FEP. A model found in Grobbelaar (1989 offers a recursive bottom-up description of the self-organization of the psychoanalytic ego as dependent on the organization of language (and affect, which is itself founded upon the tendency toward autopoiesis (self-making within the organism, which is in turn described as formally similar to the FEP. Meaningful consilience between Grobbelaar's model and the hierarchical recursive description available in Friston's (2010a theory is described. The paper concludes that the valuable contribution of the FEP to psychoanalysis

  15. Organization of the auditory pathway in the thoracic ganglia of noctuid moths.

    Science.gov (United States)

    Boyan, G; Williams, L; Fullard, J

    1990-05-08

    We describe the neuroarchitecture of the noctuid thoracic nerve cord and use this framework to interpret the organization of the auditory pathway responsible for escape behaviour in noctuid moths. Noctuid moths possess only two auditory receptors (A1, A2), in each ear. The axon of the A1 cell projects initially to a glomerulus located ventrally and medially in the metathoracic ganglion, where it bifurcates. One branch ascends in the ventral intermediate tract to the brain, the other descends in the ventral intermediate tract into abdominal neuromeres of the metathoracic ganglion. Both axons arborize in the median ventral and ring tracts in each neuromere. The central projections of the A2 cell remain largely within the metathoracic ganglion. The axon bifurcates at the midline and directs arborizations dorsally to the dorsal intermediate and median dorsal tracts, and ventrally into the ring tract where the arborizations overlap those of the A1 afferent. The afferent projections remain ipsilateral to the ear of origin. We describe a posterior auditory association area in the metathoracic ganglion in which the major arborizations of several identified interneurones overlap those of the A1 afferent and make monosynaptic connections with it. These interneurones all respond tonically to sound stimuli. We have also identified the projections of the A1 afferent, interneurones, and motor neurones in the segmentally equivalent anterior auditory association area of the mesothoracic ganglion. An interneurone with major arborizations in the same tracts as the A1 afferent, and receiving monosynaptic input from it, is described. The arborizations of higher order interneurones lie mainly in dorsal tracts along with those of flight motor neurones. All the interneurones in this anterior centre respond phasically or phasic/tonically to sound stimuli. The relevance of this anatomical organization for predator avoidance behaviour is considered and the organization of auditory pathways

  16. Multilevel compression of random walks on networks reveals hierarchical organization in large integrated systems.

    Directory of Open Access Journals (Sweden)

    Martin Rosvall

    Full Text Available To comprehend the hierarchical organization of large integrated systems, we introduce the hierarchical map equation, which reveals multilevel structures in networks. In this information-theoretic approach, we exploit the duality between compression and pattern detection; by compressing a description of a random walker as a proxy for real flow on a network, we find regularities in the network that induce this system-wide flow. Finding the shortest multilevel description of the random walker therefore gives us the best hierarchical clustering of the network--the optimal number of levels and modular partition at each level--with respect to the dynamics on the network. With a novel search algorithm, we extract and illustrate the rich multilevel organization of several large social and biological networks. For example, from the global air traffic network we uncover countries and continents, and from the pattern of scientific communication we reveal more than 100 scientific fields organized in four major disciplines: life sciences, physical sciences, ecology and earth sciences, and social sciences. In general, we find shallow hierarchical structures in globally interconnected systems, such as neural networks, and rich multilevel organizations in systems with highly separated regions, such as road networks.

  17. Where sociality and relatedness diverge: the genetic basis for hierarchical social organization in African elephants

    DEFF Research Database (Denmark)

    Wittemyer, George; Okello, John B. A.; Rasmussen, Henrik B.

    2009-01-01

    Hierarchical properties characterize elephant fission-fusion social organization whereby stable groups of individuals coalesce into higher order groups or split in a predictable manner. This hierarchical complexity is rare among animals and, as such, an examination of the factors driving its...... emergence offers unique insight into the evolution of social behaviour. Investigation of the genetic basis for such social affiliation demonstrates that while the majority of core social groups (second-tier affiliates) are significantly related, this is not exclusively the case. As such, direct benefits...

  18. Hierarchical Pore Development by Plasma Etching of Zr-Based Metal-Organic Frameworks.

    Science.gov (United States)

    DeCoste, Jared B; Rossin, Joseph A; Peterson, Gregory W

    2015-12-07

    The typically stable Zr-based metal-organic frameworks (MOFs) UiO-66 and UiO-66-NH2 were treated with tetrafluoromethane (CF4 ) and hexafluoroethane (C2 F6 ) plasmas. Through interactions between fluoride radicals from the perfluoroalkane plasma and the zirconium-oxygen bonds of the MOF, the resulting materials showed the development of mesoporosity, creating a hierarchical pore structure. It is anticipated that this strategy can be used as a post-synthetic technique for developing hierarchical networks in a variety of MOFs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Towards a Hierarchical Definition of Life, the Organism, and Death

    NARCIS (Netherlands)

    Jagers Op Akkerhuis, G.A.J.M.

    2010-01-01

    Despite hundreds of definitions, no consensus exists on a definition of life or on the closely related and problematic definitions of the organism and death. These problems retard practical and theoretical development in, for example, exobiology, artificial life, biology and evolution. This paper

  20. Sustained Activity in Hierarchical Modular Neural Networks: Self-Organized Criticality and Oscillations

    Science.gov (United States)

    Wang, Sheng-Jun; Hilgetag, Claus C.; Zhou, Changsong

    2010-01-01

    Cerebral cortical brain networks possess a number of conspicuous features of structure and dynamics. First, these networks have an intricate, non-random organization. In particular, they are structured in a hierarchical modular fashion, from large-scale regions of the whole brain, via cortical areas and area subcompartments organized as structural and functional maps to cortical columns, and finally circuits made up of individual neurons. Second, the networks display self-organized sustained activity, which is persistent in the absence of external stimuli. At the systems level, such activity is characterized by complex rhythmical oscillations over a broadband background, while at the cellular level, neuronal discharges have been observed to display avalanches, indicating that cortical networks are at the state of self-organized criticality (SOC). We explored the relationship between hierarchical neural network organization and sustained dynamics using large-scale network modeling. Previously, it was shown that sparse random networks with balanced excitation and inhibition can sustain neural activity without external stimulation. We found that a hierarchical modular architecture can generate sustained activity better than random networks. Moreover, the system can simultaneously support rhythmical oscillations and SOC, which are not present in the respective random networks. The mechanism underlying the sustained activity is that each dense module cannot sustain activity on its own, but displays SOC in the presence of weak perturbations. Therefore, the hierarchical modular networks provide the coupling among subsystems with SOC. These results imply that the hierarchical modular architecture of cortical networks plays an important role in shaping the ongoing spontaneous activity of the brain, potentially allowing the system to take advantage of both the sensitivity of critical states and the predictability and timing of oscillations for efficient information

  1. Sustained activity in hierarchical modular neural networks: self-organized criticality and oscillations.

    Science.gov (United States)

    Wang, Sheng-Jun; Hilgetag, Claus C; Zhou, Changsong

    2011-01-01

    Cerebral cortical brain networks possess a number of conspicuous features of structure and dynamics. First, these networks have an intricate, non-random organization. In particular, they are structured in a hierarchical modular fashion, from large-scale regions of the whole brain, via cortical areas and area subcompartments organized as structural and functional maps to cortical columns, and finally circuits made up of individual neurons. Second, the networks display self-organized sustained activity, which is persistent in the absence of external stimuli. At the systems level, such activity is characterized by complex rhythmical oscillations over a broadband background, while at the cellular level, neuronal discharges have been observed to display avalanches, indicating that cortical networks are at the state of self-organized criticality (SOC). We explored the relationship between hierarchical neural network organization and sustained dynamics using large-scale network modeling. Previously, it was shown that sparse random networks with balanced excitation and inhibition can sustain neural activity without external stimulation. We found that a hierarchical modular architecture can generate sustained activity better than random networks. Moreover, the system can simultaneously support rhythmical oscillations and SOC, which are not present in the respective random networks. The mechanism underlying the sustained activity is that each dense module cannot sustain activity on its own, but displays SOC in the presence of weak perturbations. Therefore, the hierarchical modular networks provide the coupling among subsystems with SOC. These results imply that the hierarchical modular architecture of cortical networks plays an important role in shaping the ongoing spontaneous activity of the brain, potentially allowing the system to take advantage of both the sensitivity of critical states and the predictability and timing of oscillations for efficient information

  2. Is Inequality Inevitable in Society? Income Distribution as a Consequence of Resource Flow in Hierarchical Organizations

    Science.gov (United States)

    Sinha, Sitabhra; Srivastava, Nisheeth

    Almost all societies, once they attain a certain level of complexity, exhibit inequality in the income of its members. Hierarchical stratification of social classes may be a major contributor to such unequal distribution of income, with intra-class variation often being negligible compared to inter-class differences. In this paper, examples from different historical periods, such as 10th century Byzantium and the Mughal empire of India in the 15th century, and different kinds of organizations, such as a criminal gang in the USA and Manufacturing & IT Services companies in India, are shown to suggest a causal relation between the hierarchical structure of social organization and the observed income inequality in societies. Proceeding from the assumption that income inequality may be a consequence of resource flow in a hierarchically structured social network, we present a model to show that empirically observed long-tailed income distribution can be explained through a process of division of assets at various levels in a hierarchical organization.

  3. Attentional selection of levels within hierarchically organized figures is mediated by object-files.

    Science.gov (United States)

    Valdés-Sosa, Mitchell J; Iglesias-Fuster, Jorge; Torres, Rosario

    2014-01-01

    Objects frequently have a hierarchical organization (tree-branch-leaf). How do we select the level to be attended? This has been explored with compound letters: a global letter built from local letters. One explanation, backed by much empirical support, is that attentional competition is biased toward certain spatial frequency (SF) bands across all locations and objects (a SF filter). This view assumes that the global and local letters are carried respectively by low and high SF bands, and that the bias can persist over time. Here we advocate a complementary view in which perception of hierarchical level is determined by how we represent letters in object-files. Although many properties bound to an object-file (i.e., position, color, even shape) can mutate without affecting its persistence over time, we posit that same object-file cannot be used to store information from different hierarchical levels. Thus, selection of level would be independent from locations but not from the way objects are represented at each moment. These views were contrasted via an attentional blink paradigm that presented letters within compound figures, but only one level at a time. Attending to two letters in rapid succession was easier if they were at the same-compared to different-levels, as predicted by both accounts. However, only the object-file account was able to explain why it was easier to report two targets on the same moving object compared to the same targets on distinct objects. The interference of different masks on target recognition was also easier to predict by the object-file account than by an SF filter. The methods introduced here allowed us to investigate attention to hierarchical levels and to object-files within the same empirical framework. The data suggests that SF information is used to structure the internal organization of object representations, a process understood best by integrating object-file theory with previous models of hierarchical perception.

  4. Intrusion Detection Method Based on Improved Growing Hierarchical Self-Organizing Map

    Institute of Scientific and Technical Information of China (English)

    张亚平; 布文秀; 苏畅; 王璐瑶; 许涵

    2016-01-01

    Considering that growing hierarchical self-organizing map(GHSOM) ignores the influence of individ-ual component in sample vector analysis, and its accurate rate in detecting unknown network attacks is relatively lower, an improved GHSOM method combined with mutual information is proposed. After theoretical analysis, experiments are conducted to illustrate the effectiveness of the proposed method by accurately clustering the input data. Based on different clusters, the complex relationship within the data can be revealed effectively.

  5. Where sociality and relatedness diverge: the genetic basis for hierarchical social organization in African elephants.

    Science.gov (United States)

    Wittemyer, George; Okello, John B A; Rasmussen, Henrik B; Arctander, Peter; Nyakaana, Silvester; Douglas-Hamilton, Iain; Siegismund, Hans R

    2009-10-07

    Hierarchical properties characterize elephant fission-fusion social organization whereby stable groups of individuals coalesce into higher order groups or split in a predictable manner. This hierarchical complexity is rare among animals and, as such, an examination of the factors driving its emergence offers unique insight into the evolution of social behaviour. Investigation of the genetic basis for such social affiliation demonstrates that while the majority of core social groups (second-tier affiliates) are significantly related, this is not exclusively the case. As such, direct benefits received through membership of these groups appear to be salient to their formation and maintenance. Further analysis revealed that the majority of groups in the two higher social echelons (third and fourth tiers) are typically not significantly related. The majority of third-tier members are matrilocal, carrying the same mtDNA control region haplotype, while matrilocality among fourth-tier groups was slightly less than expected at random. Comparison of results to those from a less disturbed population suggests that human depredation, leading to social disruption, altered the genetic underpinning of social relations in the study population. These results suggest that inclusive fitness benefits may crystallize elephant hierarchical social structuring along genetic lines when populations are undisturbed. However, indirect benefits are not critical to the formation and maintenance of second-, third- or fourth-tier level bonds, indicating the importance of direct benefits in the emergence of complex, hierarchical social relations among elephants. Future directions and conservation implications are discussed.

  6. Attentional modulation and domain-specificity underlying the neural organization of auditory categorical perception.

    Science.gov (United States)

    Bidelman, Gavin M; Walker, Breya S

    2017-03-01

    Categorical perception (CP) is highly evident in audition when listeners' perception of speech sounds abruptly shifts identity despite equidistant changes in stimulus acoustics. While CP is an inherent property of speech perception, how (if) it is expressed in other auditory modalities (e.g., music) is less clear. Moreover, prior neuroimaging studies have been equivocal on whether attentional engagement is necessary for the brain to categorically organize sound. To address these questions, we recorded neuroelectric brain responses [event-related potentials (ERPs)] from listeners as they rapidly categorized sounds along a speech and music continuum (active task) or during passive listening. Behaviorally, listeners' achieved sharper psychometric functions and faster identification for speech than musical stimuli, which was perceived in a continuous mode. Behavioral results coincided with stronger ERP differentiation between prototypical and ambiguous tokens (i.e., categorical processing) for speech but not for music. Neural correlates of CP were only observed when listeners actively attended to the auditory signal. These findings were corroborated by brain-behavior associations; changes in neural activity predicted more successful CP (psychometric slopes) for active but not passively evoked ERPs. Our results demonstrate auditory categorization is influenced by attention (active > passive) and is stronger for more familiar/overlearned stimulus domains (speech > music). In contrast to previous studies examining highly trained listeners (i.e., musicians), we infer that (i) CP skills are largely domain-specific and do not generalize to stimuli for which a listener has no immediate experience and (ii) categorical neural processing requires active engagement with the auditory stimulus.

  7. An alternative hierarchical organization of the mental disorders of the DSM-IV.

    Science.gov (United States)

    Flanagan, Elizabeth H; Keeley, Jared; Blashfield, Roger K

    2008-08-01

    With the approaching publication of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM), alternative organizations of the DSM (4th ed.; DSM-IV; American Psychiatric Association, 1994) categories have been proposed. This article compares several published alternative organizations to clinicians' organization of the DSM-IV categories. As demonstrations of their organization of DSM-IV categories, psychologists and psychiatrists sorted 66 DSM-IV diagnostic categories into groups of similar diagnoses and then made progressively larger and smaller groups of diagnoses or placed similar groups next to each other on a table. Hierarchical agglomerative data analysis of clinicians' individual sortings showed that clinicians retained many lower level DSM-IV categories (e.g., anxiety disorders, mood disorders), but not the higher level DSM-IV categories (e.g., Axis I vs. Axis II). Instead, at the highest hierarchical level, clinicians' categories resembled the structure of the first edition of the DSM (American Psychiatric Association, 1952), which followed clinicians' diagnostic decision-making scheme, dividing mental disorders into organic versus nonorganic and then psychotic versus neurotic disorders. At minimum, these data suggest a DSM organization that makes sense to clinicians.

  8. Construction of hierarchically porous metal-organic frameworks through linker labilization

    Science.gov (United States)

    Yuan, Shuai; Zou, Lanfang; Qin, Jun-Sheng; Li, Jialuo; Huang, Lan; Feng, Liang; Wang, Xuan; Bosch, Mathieu; Alsalme, Ali; Cagin, Tahir; Zhou, Hong-Cai

    2017-05-01

    A major goal of metal-organic framework (MOF) research is the expansion of pore size and volume. Although many approaches have been attempted to increase the pore size of MOF materials, it is still a challenge to construct MOFs with precisely customized pore apertures for specific applications. Herein, we present a new method, namely linker labilization, to increase the MOF porosity and pore size, giving rise to hierarchical-pore architectures. Microporous MOFs with robust metal nodes and pro-labile linkers were initially synthesized. The mesopores were subsequently created as crystal defects through the splitting of a pro-labile-linker and the removal of the linker fragments by acid treatment. We demonstrate that linker labilization method can create controllable hierarchical porous structures in stable MOFs, which facilitates the diffusion and adsorption process of guest molecules to improve the performances of MOFs in adsorption and catalysis.

  9. Hierarchically Structured Graphene Coupled Microporous Organic Polymers for Superior CO2 Capture.

    Science.gov (United States)

    Liu, Fa-Qian; Wang, Li-Li; Li, Guo-Hua; Li, Wei; Li, Chao-Qin

    2017-10-04

    Hierarchically porous materials containing interconnected macro-/meso-/micropores are promising candidates for energy storage, catalysis, and gas separation. Here, we present an effective approach for synthesizing three-dimensional (3D) sulfonated graphene coupled microporous organic polymers (SG-MOPs). The resulting SG-MOPs possess uniform macropores with an average size of ca. 350 nm, abundant mesopores, and micropores with an average size of ca. 0.6 nm. The SG-supported adsorbents exhibit a high nitrogen content (more than 38.1 wt %), high adsorption capacity (up to 3.37 mmol CO2 g(-1)), high CO2/N2 selectivity from 42 to 51, moderate heat of adsorption, as well as good stability because of the hierarchical porous structure and excellent thermal conductivity of the SG scaffold. Thus, these nitrogen-enriched adsorbents allow the overall CO2 capture process to be promising and sustainable.

  10. An organization of visual and auditory fear conditioning in the lateral amygdala.

    Science.gov (United States)

    Bergstrom, Hadley C; Johnson, Luke R

    2014-12-01

    Pavlovian fear conditioning is an evolutionary conserved and extensively studied form of associative learning and memory. In mammals, the lateral amygdala (LA) is an essential locus for Pavlovian fear learning and memory. Despite significant progress unraveling the cellular mechanisms responsible for fear conditioning, very little is known about the anatomical organization of neurons encoding fear conditioning in the LA. One key question is how fear conditioning to different sensory stimuli is organized in LA neuronal ensembles. Here we show that Pavlovian fear conditioning, formed through either the auditory or visual sensory modality, activates a similar density of LA neurons expressing a learning-induced phosphorylated extracellular signal-regulated kinase (p-ERK1/2). While the size of the neuron population specific to either memory was similar, the anatomical distribution differed. Several discrete sites in the LA contained a small but significant number of p-ERK1/2-expressing neurons specific to either sensory modality. The sites were anatomically localized to different levels of the longitudinal plane and were independent of both memory strength and the relative size of the activated neuronal population, suggesting some portion of the memory trace for auditory and visually cued fear conditioning is allocated differently in the LA. Presenting the visual stimulus by itself did not activate the same p-ERK1/2 neuron density or pattern, confirming the novelty of light alone cannot account for the specific pattern of activated neurons after visual fear conditioning. Together, these findings reveal an anatomical distribution of visual and auditory fear conditioning at the level of neuronal ensembles in the LA.

  11. Hierarchical organization of functional connectivity in the mouse brain: a complex network approach

    Science.gov (United States)

    Bardella, Giampiero; Bifone, Angelo; Gabrielli, Andrea; Gozzi, Alessandro; Squartini, Tiziano

    2016-08-01

    This paper represents a contribution to the study of the brain functional connectivity from the perspective of complex networks theory. More specifically, we apply graph theoretical analyses to provide evidence of the modular structure of the mouse brain and to shed light on its hierarchical organization. We propose a novel percolation analysis and we apply our approach to the analysis of a resting-state functional MRI data set from 41 mice. This approach reveals a robust hierarchical structure of modules persistent across different subjects. Importantly, we test this approach against a statistical benchmark (or null model) which constrains only the distributions of empirical correlations. Our results unambiguously show that the hierarchical character of the mouse brain modular structure is not trivially encoded into this lower-order constraint. Finally, we investigate the modular structure of the mouse brain by computing the Minimal Spanning Forest, a technique that identifies subnetworks characterized by the strongest internal correlations. This approach represents a faster alternative to other community detection methods and provides a means to rank modules on the basis of the strength of their internal edges.

  12. Shaping the mammalian auditory sensory organ by the planar cell polarity pathway.

    Science.gov (United States)

    Kelly, Michael; Chen, Ping

    2007-01-01

    The human ear is capable of processing sound with a remarkable resolution over a wide range of intensity and frequency. This ability depends largely on the extraordinary feats of the hearing organ, the organ of Corti and its sensory hair cells. The organ of Corti consists of precisely patterned rows of sensory hair cells and supporting cells along the length of the snail-shaped cochlear duct. On the apical surface of each hair cell, several rows of actin-containing protrusions, known as stereocilia, form a "V"-shaped staircase. The vertices of all the "V"-shaped stereocilia point away from the center of the cochlea. The uniform orientation of stereocilia in the organ of Corti manifests a distinctive form of polarity known as planar cell polarity (PCP). Functionally, the direction of stereociliary bundle deflection controls the mechanical channels located in the stereocilia for auditory transduction. In addition, hair cells are tonotopically organized along the length of the cochlea. Thus, the uniform orientation of stereociliary bundles along the length of the cochlea is critical for effective mechanotransduction and for frequency selection. Here we summarize the morphological and molecular events that bestow the structural characteristics of the mammalian hearing organ, the growth of the snail-shaped cochlear duct and the establishment of PCP in the organ of Corti. The PCP of the sensory organs in the vestibule of the inner ear will also be described briefly.

  13. Template-Free Synthesis of Hierarchical Porous Metal-Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Yanfeng [ORNL; Qiao, Zhen-an [University of Tennessee, Knoxville (UTK); Fulvio, Pasquale F [ORNL; Dai, Sheng [ORNL; Binder, Andrew J [ORNL; Tian, Chengcheng [ORNL; Nelson, Kimberly M [ORNL; Zhu, Xiang [ORNL

    2013-01-01

    A template-free synthesis of a hierarchical microporous-mesoporous metal-organic framework (MOF) of Zn(II)-2,5-dihydroxy-1,4-benzenedicarboxylate, namely Zn-MOF-74, is reported. The surface morphology and porosity of the bimodal materials can be modified by etching the pore walls with the synthesis solvent under different reaction times and different solvents. This template-free strategy allows for the preparation of stable frameworks with mesopores exceeding 15 nm, which was previously unattained by the synthesis of MOFs by ligand exten-sion method.

  14. Enforcing Access Control in Virtual Organizations Using Hierarchical Attribute-Based Encryption

    CERN Document Server

    Asim, Muhammad; Petkovic, Milan; Trivellato, Daniel; Zannone, Nicola

    2012-01-01

    Virtual organizations are dynamic, inter-organizational collaborations that involve systems and services belonging to different security domains. Several solutions have been proposed to guarantee the enforcement of the access control policies protecting the information exchanged in a distributed system, but none of them addresses the dynamicity characterizing virtual organizations. In this paper we propose a dynamic hierarchical attribute-based encryption (D-HABE) scheme that allows the institutions in a virtual organization to encrypt information according to an attribute-based policy in such a way that only users with the appropriate attributes can decrypt it. In addition, we introduce a key management scheme that determines which user is entitled to receive which attribute key from which domain authority.

  15. INFLUENCE OF THE SKELETON HIERARCHICAL ORGANIZATION ON ELECTRONIC STATE OF IONS IN BONE MATRIX

    Directory of Open Access Journals (Sweden)

    A. S. Avrunin

    2016-01-01

    Full Text Available The authors suggested the 3D-superlattice (3DSL model to describe the effect of coplanar assembly of the hydroxyapatite (HA nanocrystallites on local electronic state of ions in mineralized bone. This model is based on the main structural and functional relationships between adjacent levels of the hierarchical organization of bone tissue. In the framework of the 3DSL model the authors predicted the distinct assembly-to-crystal red shift of the unoccupied electronic states located near the bottom of the conduction band in HA and dependence of this shift on the ratio of the thickness of the hydrated layer to the crystallite size. To check these predictions the experimental X-ray absorption studies of native bone are performed near the Ca2р1/2,3/2-, P2р1/2,3/2- и O1s edges. Comparison of the measured spectra with the known spectra of the reference compounds has confirmed appearance of the distinct assembly-to-crystal red shift. The observed effect is the ground for development of new diagnostic methods for bone status and imaging changes in the local electronic structure of bone tissue by using ultrasoft X-ray absorption spectroscopy and measuring the assembly-tocrystal shifts. The experimental data analysis proved the applicability of the 3DSL model for better understanding of the hierarchical organization of bone at nanolevel.

  16. The Role of Feature Sharedness in the Hierarchical Organization of Semantic Knowledge

    Directory of Open Access Journals (Sweden)

    J. Frederico Marques

    2013-01-01

    Full Text Available Data from neuropsychological research suggest that categorizing objects at different levels of specificity requires different cognitive and neural processes. This short paper presents and discusses a theoretical hypothesis for this organization in terms of feature sharedness. It is proposed that superordinate concepts involve a larger absolute number of exemplars that share a particular feature, thus making them more resistant to damage than basic level concepts (i.e. superordinate advantage. Simultaneously, in relative terms, features are less shared overall by superordinate members than by basic level members, which imply higher executive requirements and can conversely lead to superordinate deficits. This hypothesis is discussed in relation to behavioral data from semantic dementia and stroke aphasia patients and fMRI data from healthy subjects that support the role of feature sharedness in the hierarchical organization of semantic knowledge.

  17. Microscopy of hierarchically organized TiO{sub 2} photoelectrode for dye solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Eskandar, A., E-mail: aeska07@gmail.com [Department of Electrical and Electronics, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia); Mohamed, N. M., E-mail: noranimuti-mohamed@petronas.com.my [Centre of Innovative Nanostructures and Nanodevices, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia)

    2015-07-22

    Research on improving the performance of dye solar cells has various aspects of the device being investigated. This paper analyzes the deliberately hierarchized photoelectrode configuration for DSC applications to improve the performance of DSCs. Multiple layers of differently composed TiO{sub 2} particle types namely aggregates and nanoparticles were deposited to form a photoelectrode with thickness of about 12 µm. The photoelectrodes were assembled into working DSCs with an active area of 1 cm{sup 2}. Measurement for solar power conversion performance was measured under 1 sun at AM1.5 spectrum simulated sunlight. Electron microscopy for photoelectrode analysis was conducted using Field Emission Scattering Electron Microscopy with enhanced resolution. External Quantum Efficiency was measured using a purpose built instrument. Kinetics were investigated using the Electrochemical Impedance Spectroscopy (EIS) measurement with a potentiostat. The best performing DSC is of the hierarchically organized photoelectrode with a photoconversion efficiency of 4.58%, an increase of 14% in comparison to the reference samples with fully aggregates configuration. Short circuit current density, Jsc increases by about 2.223 mA cm{sup −2} relative to the blanks. The electron microscopy confirmed expected thickness at around 10 µm and layers forming the photoelectrode being hierarchically deposited with ∼20 nm TiO{sub 2} nanoparticles and 450 nm TiO{sub 2} aggregates mixture composition. EQE improved especially for visible region of 500-550 nm light wavelengths with 12 % increase in the response of in that region. Improvement to the diffusion coefficient as measured by the EIS contributed to the performance increase of the photoelectrode configuration under investigation.

  18. A top-down hierarchical spatio-temporal process description method and its data organization

    Science.gov (United States)

    Xie, Jiong; Xue, Cunjin

    2009-10-01

    Modeling and representing spatio-temporal process is the key foundation for analyzing geographic phenomenon and acquiring spatio-temporal high-level knowledge. Spatio-temporal representation methods with bottom-up approach based on object modeling view lack of explicit definition of geographic phenomenon and finer-grained representation of spatio-temporal causal relationships. Based on significant advances in data modeling of spatio-temporal object and event, aimed to represent discrete regional dynamic phenomenon composed with group of spatio-temporal objects, a regional spatio-temporal process description method using Top-Down Hierarchical approach (STP-TDH) is proposed and a data organization structure based on relational database is designed and implemented which builds up the data structure foundation for carrying out advanced data utilization and decision-making. The land use application case indicated that process modeling with top-down approach was proved to be good with the spatio-temporal cognition characteristic of our human, and its hierarchical representation framework can depict dynamic evolution characteristic of regional phenomenon with finer-grained level and can reduce complexity of process description.

  19. Hierarchical compression of Caenorhabditis elegans locomotion reveals phenotypic differences in the organization of behaviour

    Science.gov (United States)

    2016-01-01

    Regularities in animal behaviour offer insights into the underlying organizational and functional principles of nervous systems and automated tracking provides the opportunity to extract features of behaviour directly from large-scale video data. Yet how to effectively analyse such behavioural data remains an open question. Here, we explore whether a minimum description length principle can be exploited to identify meaningful behaviours and phenotypes. We apply a dictionary compression algorithm to behavioural sequences from the nematode worm Caenorhabditis elegans freely crawling on an agar plate both with and without food and during chemotaxis. We find that the motifs identified by the compression algorithm are rare but relevant for comparisons between worms in different environments, suggesting that hierarchical compression can be a useful step in behaviour analysis. We also use compressibility as a new quantitative phenotype and find that the behaviour of wild-isolated strains of C. elegans is more compressible than that of the laboratory strain N2 as well as the majority of mutant strains examined. Importantly, in distinction to more conventional phenotypes such as overall motor activity or aggregation behaviour, the increased compressibility of wild isolates is not explained by the loss of function of the gene npr-1, which suggests that erratic locomotion is a laboratory-derived trait with a novel genetic basis. Because hierarchical compression can be applied to any sequence, we anticipate that compressibility can offer insights into the organization of behaviour in other animals including humans. PMID:27581484

  20. Empowering Change Agents in Hierarchical Organizations: Participatory Action Research in Prisons.

    Science.gov (United States)

    Penrod, Janice; Loeb, Susan J; Ladonne, Robert A; Martin, Lea M

    2016-06-01

    Participatory action research (PAR) approaches harness collaborative partnerships to stimulate change in defined communities. The purpose of this article is to illustrate key methodological strategies used in the application of PAR methods in the particularly challenging environment of a hierarchical organization. A study designed to promote sustainable, insider-generated system-level changes in the provision of end-of-life (EOL) care in the restrictive setting of six state prisons is used as an exemplar of the application of three cardinal principles of PAR. First, development of a collaborative network with active partnership between outsider academic researchers and insider co-researchers began with careful attention to understanding the culture and processes of prisons and gaining the support of organizational leadership, using qualitative data gathering and trust-building. During the implementation phase, promoting co-ownership of change in EOL care through the co-construction of knowledge and systems to enhance sustainable change required carefully-orchestrated strategies to maximize the collaborative spirit of the project. Co-researchers were empowered to examine their worlds and capture opportunities for change using new leadership skills role-modeled by the research team. Third, their local knowledge of the barriers inherent in the contextual reality of prisons was translated into achievable system change by production of a toolkit of formalized and well-rehearsed change strategies that collaborative teams were empowered to enact within their hierarchical prison environment. © 2016 Wiley Periodicals, Inc.

  1. Hierarchical compression of Caenorhabditis elegans locomotion reveals phenotypic differences in the organization of behaviour.

    Science.gov (United States)

    Gomez-Marin, Alex; Stephens, Greg J; Brown, André E X

    2016-08-01

    Regularities in animal behaviour offer insights into the underlying organizational and functional principles of nervous systems and automated tracking provides the opportunity to extract features of behaviour directly from large-scale video data. Yet how to effectively analyse such behavioural data remains an open question. Here, we explore whether a minimum description length principle can be exploited to identify meaningful behaviours and phenotypes. We apply a dictionary compression algorithm to behavioural sequences from the nematode worm Caenorhabditis elegans freely crawling on an agar plate both with and without food and during chemotaxis. We find that the motifs identified by the compression algorithm are rare but relevant for comparisons between worms in different environments, suggesting that hierarchical compression can be a useful step in behaviour analysis. We also use compressibility as a new quantitative phenotype and find that the behaviour of wild-isolated strains of C. elegans is more compressible than that of the laboratory strain N2 as well as the majority of mutant strains examined. Importantly, in distinction to more conventional phenotypes such as overall motor activity or aggregation behaviour, the increased compressibility of wild isolates is not explained by the loss of function of the gene npr-1, which suggests that erratic locomotion is a laboratory-derived trait with a novel genetic basis. Because hierarchical compression can be applied to any sequence, we anticipate that compressibility can offer insights into the organization of behaviour in other animals including humans.

  2. Immunophenotype Discovery, Hierarchical Organization, and Template-based Classification of Flow Cytometry Samples

    Directory of Open Access Journals (Sweden)

    Ariful Azad

    2016-08-01

    Full Text Available We describe algorithms for discovering immunophenotypes from large collections of flow cytometry (FC samples, and using them to organize the samples into a hierarchy based on phenotypic similarity. The hierarchical organization is helpful for effective and robust cytometry data mining, including the creation of collections of cell populations characteristic of different classes of samples, robust classification, and anomaly detection. We summarize a set of samples belonging to a biological class or category with a statistically derived template for the class. Whereas individual samples are represented in terms of their cell populations (clusters, a template consists of generic meta-populations (a group of homogeneous cell populations obtained from the samples in a class that describe key phenotypes shared among all those samples. We organize an FC data collection in a hierarchical data structure that supports the identification of immunophenotypes relevant to clinical diagnosis. A robust template-based classification scheme is also developed, but our primary focus is in the discovery of phenotypic signatures and inter-sample relationships in an FC data collection. This collective analysis approach is more efficient and robust since templates describe phenotypic signatures common to cell populations in several samples, while ignoring noise and small sample-specific variations.We have applied the template-base scheme to analyze several data setsincluding one representing a healthy immune system, and one of Acute Myeloid Leukemia (AMLsamples. The last task is challenging due to the phenotypic heterogeneity of the severalsubtypes of AML. However, we identified thirteen immunophenotypes corresponding to subtypes of AML, and were able to distinguish Acute Promyelocytic Leukemia from other subtypes of AML.

  3. Detecting and interpreting distortions in hierarchical organization of complex time series

    CERN Document Server

    Drożdż, Stanisław

    2015-01-01

    Hierarchical organization is a cornerstone of complexity and multifractality constitutes its central quantifying concept. For model uniform cascades the corresponding singularity spectra are symmetric while those extracted from empirical data are often asymmetric. Using the selected time series representing such diverse phenomena like price changes and inter-transaction times in the financial markets, sentence length variability in the narrative texts, Missouri River discharge and Sunspot Number variability as examples, we show that the resulting singularity spectra appear strongly asymmetric, more often left-sided but in some cases also right-sided. We present a unified view on the origin of such effects and indicate that they may be crucially informative for identifying composition of the time series. One particularly intriguing case of this later kind of asymmetry is detected in the daily reported Sunspot Number variability. This signals that either the commonly used famous Wolf formula distorts the real d...

  4. Modularity and hierarchical organization of action programs in human acquisition of graphic skills.

    Science.gov (United States)

    Manoel, Edison de J; Basso, Luciano; Correa, Umberto C; Tani, Go

    2002-12-25

    If motor or action programs become modules with practice their defining features (e.g. relative timing) should remain relatively invariant in new tasks. To test this hypothesis 24 adults practiced a graphic skill over 100 trials and were transferred to a more complex task enclosing the practiced figure. The data acquired by a digital tablet resulted in total movement and total pause times to draw the figure indicating skill acquisition and variability measures of relative timing and pause time and sequencing referring to features that identify a module. Being transferred to a more complex task did not lead to significant increases in the time to perform the criterion figure embedded in the new pattern. Modularity was evidenced by the stability of relative timing and sequencing shown in the performance of the criterion figure. Hence, it might be that action programs become modules that are then hierarchically organized to form more complex skills.

  5. The arbitration-extension hypothesis: a hierarchical interpretation of the functional organization of the basal ganglia

    Directory of Open Access Journals (Sweden)

    Iman eKamali Sarvestani

    2011-03-01

    Full Text Available Based on known anatomy and physiology, we present a hypothesis where the basal gangliamotor loop is hierarchically organized in two main subsystems: the arbitration system andthe extension system. The arbitration system, comprised of the subthalamic nucleus, globuspallidus, and pedunculopontine nucleus, serves the role of selecting one out of several candidateactions as they are ascending from various brain stem motor regions and aggregated in thecentromedian thalamus or descending from the extension system or from the cerebral cortex.This system is an action-input/action-output system whose winner-take-all mechanism findsthe strongest response among several candidates to execute. This decision is communicatedback to the brain stem by facilitating the desired action via cholinergic/glutamatergic projectionsand suppressing conflicting alternatives via GABAergic connections. The extension system,comprised of the striatum and, again, globus pallidus, can extend the repertoire of responsesby learning to associate novel complex states to certain actions. This system is a state-input/action-output system, whose organization enables it to encode arbitrarily complex Booleanlogic rules using striatal neurons that only fire given specific constellations of inputs (BooleanAND and pallidal neurons that are silenced by any striatal input (Boolean OR. We demonstratethe capabilities of this hierarchical system by a computational model where a simulatedgeneric animal interacts with an environment by selecting direction of movement basedon combinations of sensory stimuli, some being appetitive, others aversive or neutral. Whilethe arbitration system can autonomously handle conflicting actions proposed by brain stemmotor nuclei, the extension system is required to execute learned actions not suggested byexternal motor centers. Being precise in the functional role of each component of the system,this hypothesis generates several readily testable predictions.

  6. IC-Finder: inferring robustly the hierarchical organization of chromatin folding.

    Science.gov (United States)

    Haddad, Noelle; Vaillant, Cédric; Jost, Daniel

    2017-01-26

    The spatial organization of the genome plays a crucial role in the regulation of gene expression. Recent experimental techniques like Hi-C have emphasized the segmentation of genomes into interaction compartments that constitute conserved functional domains participating in the maintenance of a proper cell identity. Here, we propose a novel method, IC-Finder, to identify interaction compartments (IC) from experimental Hi-C maps. IC-Finder is based on a hierarchical clustering approach that we adapted to account for the polymeric nature of chromatin. Based on a benchmark of realistic in silico Hi-C maps, we show that IC-Finder is one of the best methods in terms of reliability and is the most efficient numerically. IC-Finder proposes two original options: a probabilistic description of the inferred compartments and the possibility to explore the various hierarchies of chromatin organization. Applying the method to experimental data in fly and human, we show how the predicted segmentation may depend on the normalization scheme and how 3D compartmentalization is tightly associated with epigenomic information. IC-Finder provides a robust and generic 'all-in-one' tool to uncover the general principles of 3D chromatin folding and their influence on gene regulation. The software is available at http://membres-timc.imag.fr/Daniel.Jost/DJ-TIMC/Software.html.

  7. Facile Carbonization of Microporous Organic Polymers into Hierarchically Porous Carbons Targeted for Effective CO2 Uptake at Low Pressures.

    Science.gov (United States)

    Gu, Shuai; He, Jianqiao; Zhu, Yunlong; Wang, Zhiqiang; Chen, Dongyang; Yu, Guipeng; Pan, Chunyue; Guan, Jianguo; Tao, Kai

    2016-07-20

    The advent of microporous organic polymers (MOPs) has delivered great potential in gas storage and separation (CCS). However, the presence of only micropores in these polymers often imposes diffusion limitations, which has resulted in the low utilization of MOPs in CCS. Herein, facile chemical activation of the single microporous organic polymers (MOPs) resulted in a series of hierarchically porous carbons with hierarchically meso-microporous structures and high CO2 uptake capacities at low pressures. The MOPs precursors (termed as MOP-7-10) with a simple narrow micropore structure obtained in this work possess moderate apparent BET surface areas ranging from 479 to 819 m(2) g(-1). By comparing different activating agents for the carbonization of these MOPs matrials, we found the optimized carbon matrials MOPs-C activated by KOH show unique hierarchically porous structures with a significant expansion of dominant pore size from micropores to mesopores, whereas their microporosity is also significantly improved, which was evidenced by a significant increase in the micropore volume (from 0.27 to 0.68 cm(3) g(-1)). This maybe related to the collapse and the structural rearrangement of the polymer farmeworks resulted from the activation of the activating agent KOH at high temperature. The as-made hierarchically porous carbons MOPs-C show an obvious increase in the BET surface area (from 819 to 1824 m(2) g(-1)). And the unique hierarchically porous structures of MOPs-C significantly contributed to the enhancement of the CO2 capture capacities, which are up to 214 mg g(-1) (at 273 K and 1 bar) and 52 mg g(-1) (at 273 K and 0.15 bar), superior to those of the most known MOPs and porous carbons. The high physicochemical stabilities and appropriate isosteric adsorption heats as well as high CO2/N2 ideal selectivities endow these hierarchically porous carbon materials great potential in gas sorption and separation.

  8. Hierarchically Organized Behavior and Its Neural Foundations: A Reinforcement Learning Perspective

    Science.gov (United States)

    Botvinick, Matthew M.; Niv, Yael; Barto, Andrew C.

    2009-01-01

    Research on human and animal behavior has long emphasized its hierarchical structure--the divisibility of ongoing behavior into discrete tasks, which are comprised of subtask sequences, which in turn are built of simple actions. The hierarchical structure of behavior has also been of enduring interest within neuroscience, where it has been widely…

  9. Hierarchically Organized Behavior and Its Neural Foundations: A Reinforcement Learning Perspective

    Science.gov (United States)

    Botvinick, Matthew M.; Niv, Yael; Barto, Andrew C.

    2009-01-01

    Research on human and animal behavior has long emphasized its hierarchical structure--the divisibility of ongoing behavior into discrete tasks, which are comprised of subtask sequences, which in turn are built of simple actions. The hierarchical structure of behavior has also been of enduring interest within neuroscience, where it has been widely…

  10. How Amelogenin Orchestrates the Organization of Hierarchical Elongated Microstructures of Apatite

    Science.gov (United States)

    Yang, Xiudong; Wang, Lijun; Qin, Yueling; Sun, Zhi; Henneman, Zachary J.; Moradian-Oldak, Janet; Nancollas, George H.

    2010-01-01

    Amelogenin (Amel) accelerates the nucleation of hydroxyapatite (HAP) in supersaturated solutions of calcium phosphate (Ca-P), shortening the induction time (delay period), under near-physiological conditions of pH, temperature, and ionic strength. Hierarchically organized Amel and amorphous calcium phosphate (ACP) nanorod microstructures are formed involving co-assembly of Amel-ACP particles at low supersaturations and low protein concentrations in a slow, well-controlled, constant composition (CC) crystallization system. At the earliest nucleation stages, the CC method allows the capture of prenucleation clusters and intermediate nanoclusers, spherical nanoparticles, and nanochains prior to enamel–like nanorod microstructure formations at later maturation stages. Amel-ACP nanoscaled building blocks are formed spontaneously by synergistic interactions between flexible Amel protein molecules and Ca-P prenucleation clusters, and these spherical nanoparticles evolve by orientated aggregation to form nanochains. Our results suggest that, in vivo, Amel may determine the structure of enamel by controlling prenucleation cluster aggregation at the earliest stages by forming stable Amel-ACP microstructures prior to subsequent crystal growth and mineral maturation. PMID:20104924

  11. Impact of informal networks on opinion dynamics in hierarchically formal organization

    Science.gov (United States)

    Song, Xiao; Shi, Wen; Ma, Yaofei; Yang, Chen

    2015-10-01

    Traditional opinion dynamics model focused mainly on the conditions under which a group of agents would reach a consensus. Conclusion has been gained that continuous opinion dynamics are subject to the constraint that convergent opinion adjustment only proceeds when opinion difference is below a given tolerance. This conclusion is useful but neglected the fact that an organization often consists of overlapped networks including formally hierarchical network and small-world/scale-free informal networks. To study the impact of different types of informal networks on converging speed or the number of opinion clusters, four typical types of informal networks (small-world, scale-free, tree and fully connected) are modeled and proposed as complements to formal communications. Experiments to compare formal network and hybrid networks are then carried out. It is observed that opinion dynamics with supplemented communications of informal networks can benefit convergence speed and reduce opinion clusters. More importantly, it is revealed that three key factors of informal networks affect their impact on formal network. These factors of informal network in descending orders are: agents' tolerances, scale and number of links.

  12. Detecting and interpreting distortions in hierarchical organization of complex time series

    Science.gov (United States)

    DroŻdŻ, Stanisław; OświÈ©cimka, Paweł

    2015-03-01

    Hierarchical organization is a cornerstone of complexity and multifractality constitutes its central quantifying concept. For model uniform cascades the corresponding singularity spectra are symmetric while those extracted from empirical data are often asymmetric. Using selected time series representing such diverse phenomena as price changes and intertransaction times in financial markets, sentence length variability in narrative texts, Missouri River discharge, and sunspot number variability as examples, we show that the resulting singularity spectra appear strongly asymmetric, more often left sided but in some cases also right sided. We present a unified view on the origin of such effects and indicate that they may be crucially informative for identifying the composition of the time series. One particularly intriguing case of this latter kind of asymmetry is detected in the daily reported sunspot number variability. This signals that either the commonly used famous Wolf formula distorts the real dynamics in expressing the largest sunspot numbers or, if not, that their dynamics is governed by a somewhat different mechanism.

  13. Spider's super-glue: thread anchors are composite adhesives with synergistic hierarchical organization.

    Science.gov (United States)

    Wolff, Jonas O; Grawe, Ingo; Wirth, Marina; Karstedt, André; Gorb, Stanislav N

    2015-03-28

    Silk is a key innovation in spiders, fascinating both biologists and material scientists. However, to fulfil their biological function silken threads must be strongly fastened to substrates or other threads. The majority of modern spiders produce a unique and rather unexplored bio-adhesive: the two-compound pyriform secretion, which is spun into elaborate patterns (so called attachment discs) and used to anchor silken threads to substrates. Strong adhesion is achieved on a high variety of surfaces with a minimum of material consumption. Pyriform threads polymerize under ambient conditions, become functional within less than a second and can remain stable for years. They are biodegradable, biocompatible and highly versatile - the adhesion and the overall toughness of the attachment disc can be controlled by spinneret movements on a macroscopic level (ref. 1: V. Sahni et al., Nat. Commun., 2012, 3, 1106, DOI: 10.1038/ncomms2099). We found that the pyriform thread is a silk fibre that is coated with glue-like cement consisting of aligned nanofibrils, lipid enclosures and a dense, isotropic boundary layer. The threads are spun in a meshwork pattern that promotes stress distribution and crack arresting. Our results demonstrate, that hierarchical organization and fibre embedding may explain the high adhesive strength and flaw tolerance of a structure made by the same, rather simple type of silk glands.

  14. Cortico-amygdala-striatal circuits are organized as hierarchical subsystems through the primate amygdala.

    Science.gov (United States)

    Cho, Youngsun T; Ernst, Monique; Fudge, Julie L

    2013-08-28

    The prefrontal and insula cortex, amygdala, and striatum are key regions for emotional processing, yet the amygdala's role as an interface between the cortex and striatum is not well understood. In the nonhuman primate (Macaque fascicularis), we analyzed a collection of bidirectional tracer injections in the amygdala to understand how cortical inputs and striatal outputs are organized to form integrated cortico-amygdala-striatal circuits. Overall, diverse prefrontal and insular cortical regions projected to the basal and accessory basal nuclei of the amygdala. In turn, these amygdala regions projected to widespread striatal domains extending well beyond the classic ventral striatum. Analysis of the cases in aggregate revealed a topographic colocalization of cortical inputs and striatal outputs in the amygdala that was additionally distinguished by cortical cytoarchitecture. Specifically, the degree of cortical laminar differentiation of the cortical inputs predicted amygdalostriatal targets, and distinguished three main cortico-amygdala-striatal circuits. These three circuits were categorized as "primitive," "intermediate," and "developed," respectively, to emphasize the relative phylogenetic and ontogenetic features of the cortical inputs. Within the amygdala, these circuits appeared arranged in a pyramidal-like fashion, with the primitive circuit found in all examined subregions, and subsequent circuits hierarchically layered in discrete amygdala subregions. This arrangement suggests a stepwise integration of the functions of these circuits across amygdala subregions, providing a potential mechanism through which internal emotional states are managed with external social and sensory information toward emotionally informed complex behaviors.

  15. Synthesis of strontium carbonate rods and hierarchical branches in the presence of two organic additives

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Long; Chen, Guoping; Wang, Xixi; Fang, Hongxia; Wu, Chengxiu; Xing, Tiantian [Department of Chemistry, Huangshan University, Huangshan 245041 (China)

    2010-03-15

    In this paper, strontium carbonate (SrCO{sub 3}) crystals have been synthesized in the presence of two organic additives, including sodium citrate and hexamethylenetetramine (HMT). Scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, X-ray powder diffractometry and selected area electron diffraction (SAED) were used to characterize the products. The results indicate that SrCO{sub 3}rods with the ratio of length to diameter about 20 are obtained in the aqueous solution containing sodium citrate. While polycrystalline SrCO{sub 3} hierarchical branches with about 10 {mu}m length are produced by using HMT.The possible formation mechanism of the SrCO{sub 3}crystals obtained in above two systems is discussed, which can be interpreted by particle-aggregation based non-classical crystallization laws. Sodium citrate and HMT may direct the formation of SrCO{sub 3} rod-like or branch-like structures by adsorbing onto certain facets of SrCO{sub 3} crystals. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Hybrid organic-inorganic heterojunction solar cells with 12% efficiency by utilizing flexible film-silicon with a hierarchical surface.

    Science.gov (United States)

    Thiyagu, Subramani; Hsueh, Chen-Chih; Liu, Chien-Ting; Syu, Hong-Jhang; Lin, Tzu-Ching; Lin, Ching-Fuh

    2014-03-21

    This paper reports an organic-inorganic hybrid solar cell with a hierarchical surface composed of high density silicon nanoholes and micro-desert textures. High-efficiency organic-inorganic hybrid solar cell Si/PEDOT-PSS with a hierarchical surface, showing a power conversion efficiency of 12%. The structure provides excellent light absorption over 97% for the spectral range of 300 to 1100 nm with a thickness of 60 μm due to internal multiple reflections caused by subwavelength features of high density silicon nanoholes and micro-desert textures. In addition, from the angle of incidence (AOI) observed, even at the large angle of 75°, the reflectance value still exhibits less than 1%. With the advantage of very thin silicon material and inexpensive processing, hybrid silicon/polymer solar cells are promising for various applications and thus could be an economically feasible alternative energy solution in the future.

  17. Leading processes of patient care and treatment in hierarchical healthcare organizations in Sweden--process managers' experiences.

    Science.gov (United States)

    Nilsson, Kerstin; Sandoff, Mette

    2015-01-01

    The purpose of this study is to gain better understanding of the roles and functions of process managers by describing Swedish process managers' experiences of leading processes involving patient care and treatment when working in a hierarchical health-care organization. This study is based on an explorative design. The data were gathered from interviews with 12 process managers at three Swedish hospitals. These data underwent qualitative and interpretative analysis with a modified editing style. The process managers' experiences of leading processes in a hierarchical health-care organization are described under three themes: having or not having a mandate, exposure to conflict situations and leading process development. The results indicate a need for clarity regarding process manager's responsibility and work content, which need to be communicated to all managers and staff involved in the patient care and treatment process, irrespective of department. There also needs to be an emphasis on realistic expectations and orientation of the goals that are an intrinsic part of the task of being a process manager. Generalizations from the results of the qualitative interview studies are limited, but a deeper understanding of the phenomenon was reached, which, in turn, can be transferred to similar settings. This study contributes qualitative descriptions of leading care and treatment processes in a functional, hierarchical health-care organization from process managers' experiences, a subject that has not been investigated earlier.

  18. Hierarchical Self-Organization of ABn Dendron-type Giant Molecules into Supramolecular Lattice Sequence

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xueyan; Zhang, Ruimeng; Li, Yiwen; Hong, You-lee; Guo, Dong; Lang, Kening; Wu, Kuan-Yi; Huang, Mingjun; Mao, Jialin; Wesdemiotis, Chrys; Nishiyama, Yusuke; Zhang, Wei; Zhang, Wei; Miyoshi, Toshikazu; Li, Tao; Chang, Stephen Z. D.

    2017-08-23

    To understand the hierarchical self-organization behaviors of soft materials as well as their dependence on molecular geometry, a series of ABn dendron-type giant molecules based on polyhedral oligomeric silsesquioxane (POSS) nanoparticles were designed and synthesized. The apex of these molecules is a hydrophilic POSS cage with fourteen hydroxyl groups (denoted DPOSS). At its periphery, there are different numbers (n = 1–8) of hydrophobic POSS cages with seven isobutyl groups (denoted BPOSS), connected to the apical DPOSS via flexible dendron type linker(s). With varying the BPOSS number from one to seven, a supramolecular lattice formation sequence ranging from lamella (DPOSS-BPOSS), double gyroid (space group of Ia3 ̅d, DPOSS-BPOSS2), hexagonal cylinder (space group of P6mm, DPOSS-BPOSS3), Frank-Kasper A15 (space group of Pm3 ̅n, DPOSS-BPOSS4, DPOSS-BPOSS5, and DPOSS-BPOSS6), to Frank-Kasper sigma (space group of P42/mnm, DPOSS-BPOSS7) phases can be observed. The nanostructure formations in this series of ABn dendron-type giant molecules are mainly directed by the macromolecular geometric shapes. Furthermore, within each spherical motif, the soft spherical core is consisted of hydrophilic DPOSS cages with flexible linkages, while the hydrophobic BPOSS cages form the relative rigid shell and contact with neighbors to provide decreased interfaces among the spherical motifs for constructing final polyhedral motifs in these Frank-Kasper lattices. This study provides the design principle of macromolecules with specific geometric shapes and functional groups to achieve anticipated structures and macroscopic properties.

  19. Hierarchical Self-Organization of AB n Dendron-like Molecules into a Supramolecular Lattice Sequence.

    Science.gov (United States)

    Feng, Xueyan; Zhang, Ruimeng; Li, Yiwen; Hong, You-Lee; Guo, Dong; Lang, Kening; Wu, Kuan-Yi; Huang, Mingjun; Mao, Jialin; Wesdemiotis, Chrys; Nishiyama, Yusuke; Zhang, Wei; Zhang, Wei; Miyoshi, Toshikazu; Li, Tao; Cheng, Stephen Z D

    2017-08-23

    To understand the hierarchical self-organization behaviors of soft materials as well as their dependence on molecular geometry, a series of AB n dendron-like molecules based on polyhedral oligomeric silsesquioxane (POSS) nanoparticles were designed and synthesized. The apex of these molecules is a hydrophilic POSS cage with 14 hydroxyl groups (denoted DPOSS). At its periphery, there are different numbers (n = 1-8) of hydrophobic POSS cages with seven isobutyl groups (denoted BPOSS), connected to the apical DPOSS via flexible dendron type linker(s). By varying the BPOSS number from one to seven, a supramolecular lattice formation sequence ranging from lamella (DPOSS-BPOSS), double gyroid (space group of Ia3̅d, DPOSS-BPOSS2), hexagonal cylinder (plane group of P6mm, DPOSS-BPOSS3), Frank-Kasper A15 (space group of Pm3̅n, DPOSS-BPOSS4, DPOSS-BPOSS5, and DPOSS-BPOSS6), to Frank-Kasper sigma (space group of P42/mnm, DPOSS-BPOSS7) phases can be observed. The nanostructure formations in this series of AB n dendron-like molecules are mainly directed by the molecular geometric shapes. Furthermore, within each spherical motif, the spherical core consists hydrophilic DPOSS cages with flexible linkages, while the hydrophobic BPOSS cages form the relative rigid shell, and contact with neighbors to provide decreased interfaces among the spherical motifs for constructing final polyhedral motifs in these Frank-Kasper lattices. This study provides the design principle of molecules with specific geometric shapes and functional groups to achieve anticipated structures and macroscopic properties.

  20. Ionic liquid assisted hydrothermal fabrication of hierarchically organized γ-AlOOH hollow sphere

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhe, E-mail: tangzhe1983@163.com [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China); Liu, Yunqi, E-mail: liuyq@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China); Li, Guangci, E-mail: liguangci1984@yahoo.com.cn [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China); Hu, Xiaofu, E-mail: hjj19850922@126.cn [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China); Liu, Chenguang, E-mail: cgliu@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China)

    2012-11-15

    Highlights: ► The γ-AlOOH hollow spheres were synthesized via an ionic liquid-assisted hydrothermal treatment. ► Ionic liquid plays an important role in the morphology of the product. ► Ionic liquid can be easily removed from the product and reused in next experiment. ► A “aggregation–solution–recrystallization” formation mechanism may occur in the system. -- Abstract: Hierarchically organized γ-AlOOH hollow spheres with nanoflake-like porous surface texture have been successfully synthesized via an ionic liquid-assisted hydrothermal synthesis method in citric acid monohydrate (CAMs). It was found that ionic liquid [bmim]{sup +}Cl{sup −} played an important role in the morphology of the product due to its strong interactions with reaction particles. The samples were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM). The results show that the product has narrow particle size distribution (500–900 nm particle diameter range), high specific surface area (240.5 m{sup 2}/g) and large pore volume (0.61 cm{sup 3}/g). The corresponding γ-Al{sub 2}O{sub 3} hollow spheres can be obtained by calcining it at 550 °C for 3 h. The proposed formation mechanism and other influencing factors of the γ-AlOOH hollow sphere material, such as reaction temperature, reaction duration, CAMs and urea, have also been investigated.

  1. Organization of Estrogen-Associated Circuits in the Mouse Primary Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Liisa A. Tremere

    2011-01-01

    Full Text Available Sex steroid hormones influence the perceptual processing of sensory signals in vertebrates. In particular, decades of research have shown that circulating levels of estrogen correlate with hearing function. The mechanisms and sites of action supporting this sensory-neuroendocrine modulation, however, remain unknown. Here we combined a molecular cloning strategy, fluorescence in-situ hybridization and unbiased quantification methods to show that estrogen-producing and -sensitive neurons heavily populate the adult mouse primary auditory cortex (AI. We also show that auditory experience in freely-behaving animals engages estrogen-producing and -sensitive neurons in AI. These estrogen-associated networks are greatly stable, and do not quantitatively change as a result of acute episodes of sensory experience. We further demonstrate the neurochemical identity of estrogen-producing and estrogen-sensitive neurons in AI and show that these cell populations are phenotypically distinct. Our findings provide the first direct demonstration that estrogen-associated circuits are highly prevalent and engaged by sensory experience in the mouse auditory cortex, and suggest that previous correlations between estrogen levels and hearing function may be related to brain-generated hormone production. Finally, our findings suggest that estrogenic modulation may be a central component of the operational framework of central auditory networks.

  2. Modular networks with hierarchical organization: The dynamical implications of complex structure

    Indian Academy of Sciences (India)

    Raj Kumar Pan; Sitabhra Sinha

    2008-08-01

    Several networks occurring in real life have modular structures that are arranged in a hierarchical fashion. In this paper, we have proposed a model for such networks, using a stochastic generation method. Using this model we show that, the scaling relation between the clustering and degree of the nodes is not a necessary property of hierarchical modular networks, as had previously been suggested on the basis of a deterministically constructed model. We also look at dynamics on such networks, in particular, the stability of equilibria of network dynamics and of synchronized activity in the network. For both of these, we find that, increasing modularity or the number of hierarchical levels tends to increase the probability of instability. As both hierarchy and modularity are seen in natural systems, which necessarily have to be robust against environmental fluctuations, we conclude that additional constraints are necessary for the emergence of hierarchical structure, similar to the occurrence of modularity through multi-constraint optimization as shown by us previously.

  3. Comparative observation of protective effects of earplug and barrel on auditory organs of guinea pigs exposed to experimental blast underpressure

    Institute of Scientific and Technical Information of China (English)

    LI Chao-jun; ZHU Pei-fang; LIU Zhao-hua; WANG Zheng-guo; YANG Cheng; CHEN Hai-bin; NING Xin; ZHOU Ji-hong; Chen Jian

    2006-01-01

    Objective: To explore the protective effects of earplug and barrel on auditory organs of guinea pigs exposed to experimental blast underpressure (BUP).Methods: The hearing thresholds of the guinea pigs were assessed with auditory brainstem responses (ABR).The traumatic levels of tympanic membrane and ossicular chain were observed under stereo-microscope. The rate of outer hair cells (OHCs) loss was analyzed using a light microscope. The changes of guinea pigs protected with barrel and earplug were compared with those of the control group without any protection.Results: An important ABR threshold shift of the guinea pigs without any protection was detected from 8h to 14d after being exposed to BUP with a peak ranging from -64.5kPa to -69.3kPa (P<0.01). The rate of perforation of tympanic membrane reached 87.5 % and that of total OHCs loss was 19.46% + 5.38% at 14d after exposure. The guinea pigs protected with barrel and earplug had lower ABR threshold and total OHCs loss rate compared with the animals without any protection (P < 0.01 ). All of the tympanic membrane and ossicular chain of the protected animals maintained their integrities.Meanwhile, the guinea pigs protected with the barrel had lower ABR threshold and total OHCs loss rate than those with earplug (P<0.01).Conclusions: The earplug and barrel have protective effects against BUP-induced trauma on auditory organs of the guinea pigs and the protective effects of barrel are better than those of earplug.

  4. Specialization of Binaural Responses in Ventral Auditory Cortices

    Science.gov (United States)

    Higgins, Nathan C.; Storace, Douglas A.; Escabí, Monty A.

    2010-01-01

    Accurate orientation to sound under challenging conditions requires auditory cortex, but it is unclear how spatial attributes of the auditory scene are represented at this level. Current organization schemes follow a functional division whereby dorsal and ventral auditory cortices specialize to encode spatial and object features of sound source, respectively. However, few studies have examined spatial cue sensitivities in ventral cortices to support or reject such schemes. Here Fourier optical imaging was used to quantify best frequency responses and corresponding gradient organization in primary (A1), anterior, posterior, ventral (VAF), and suprarhinal (SRAF) auditory fields of the rat. Spike rate sensitivities to binaural interaural level difference (ILD) and average binaural level cues were probed in A1 and two ventral cortices, VAF and SRAF. Continuous distributions of best ILDs and ILD tuning metrics were observed in all cortices, suggesting this horizontal position cue is well covered. VAF and caudal SRAF in the right cerebral hemisphere responded maximally to midline horizontal position cues, whereas A1 and rostral SRAF responded maximally to ILD cues favoring more eccentric positions in the contralateral sound hemifield. SRAF had the highest incidence of binaural facilitation for ILD cues corresponding to midline positions, supporting current theories that auditory cortices have specialized and hierarchical functional organization. PMID:20980610

  5. Stimulus transmission in the auditory receptor organs of the foreleg of bushcrickets (Tettigoniidae) I. The role of the tympana.

    Science.gov (United States)

    Bangert, M; Kalmring, K; Sickmann, T; Stephen, R; Jatho, M; Lakes-Harlan, R

    1998-01-01

    The auditory organs of the tettigoniid are located just below the femoral tibial joint in the forelegs. Structurally each auditory organ consists of a tonotopically organized crista acustica and intermediate organ and associated sound conducting structures; an acoustic trachea and two lateral tympanic membranes located at the level of the receptor complex. The receptor cells and associated satellite structures are located in a channel filled with hemolymph fluid. The vibratory response characteristics of the tympanic membranes generated by sound stimulation over the frequency range 2-40 kHz have been studied using laser vibrometry. The acoustic trachea was found to be the principal structure through which sound energy reached the tympana. The velocity of propagation down the trachea was observed to be independent of the frequency and appreciably lower than the velocity of sound in free space. Structurally the tympana are found to be partially in contact with the air in the trachea and with the hemolymph in the channel containing the receptor cells. The two tympana were found to oscillate in phase, with a broad band frequency response, have linear coherent response characteristics and small time constant. Higher modes of vibration were not observed. Measurements of the pattern of vibration of the tympana showed that these structures vibrate as hinged flaps rather than vibrating stretched membranes. These findings, together with the morphology of the organ and physiological data from the receptor cells, suggest the possibility of an impedance matching function for the tympana in the transmission of acoustic energy to the receptor cells in the tettigoniid ear.

  6. Testing Edge versus Hierarchical C2 Organizations using the ELICIT Platform and Common Identification Picture Tool

    Science.gov (United States)

    2011-06-01

    application designed for conducting human-in-the-loop experiments focused on information and social domain phenomena (Martin and Mc Ever, 2008...environment designed to experiment and research differences between Edge and Hierarchical organizational configurations within the information and social ...indicated in the following tables. Tests of Normality ,132 17 ,200* ,927 17 ,191 ,131 17 ,200* ,919 17 ,141 Grupo Edge SIN Edge CON Rend Statistic df Sig

  7. Facile preparation of hierarchically porous carbons from metal-organic gels and their application in energy storage

    Science.gov (United States)

    Xia, Wei; Qiu, Bin; Xia, Dingguo; Zou, Ruqiang

    2013-06-01

    Porous carbon materials have numerous applications due to their thermal and chemical stability, high surface area and low densities. However, conventional preparing porous carbon through zeolite or silica templates casting has been criticized by the costly and/or toxic procedure. Creating three-dimensional (3D) carbon products is another challenge. Here, we report a facile way to prepare porous carbons from metal-organic gel (MOG) template, an extended metal-organic framework (MOF) structure. We surprisingly found that the carbon products inherit the highly porous nature of MOF and combine with gel's integrated character, which results in hierarchical porous architectures with ultrahigh surface areas and quite large pore volumes. They exhibit considerable hydrogen uptake and excellent electrochemical performance as cathode material for lithium-sulfur battery. This work provides a general method to fast and clean synthesis of porous carbon materials and opens new avenues for the application of metal-organic gel in energy storage.

  8. Automation of control and analysis of execution of official duties and instructions in the hierarchical organization

    Directory of Open Access Journals (Sweden)

    Demchenko A.I.

    2017-01-01

    Full Text Available The article considers the problem of monitoring over execution of official duties of employees. This problem is characteristic of the enterprises having a hierarchical management structure. The functions and the modes of monitoring are defined, the types of analysis of the staff activities are provided. The description of the program complex allowing distributing functions and instructions for between the employees is given. The developed computer program allows tracking the performance, creating reports. The computer program has a demarcation of access rights and provides the can be operated in both local, and a large-scale network.

  9. Hierarchically porous silicon-carbon-nitrogen hybrid materials towards highly efficient and selective adsorption of organic dyes.

    Science.gov (United States)

    Meng, Lala; Zhang, Xiaofei; Tang, Yusheng; Su, Kehe; Kong, Jie

    2015-01-21

    The hierarchically macro/micro-porous silicon-carbon-nitrogen (Si-C-N) hybrid material was presented with novel functionalities of totally selective and highly efficient adsorption for organic dyes. The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates. Owing to the Van der Waals force between sp-hybridized carbon domains and triphenyl structure of dyes, and electrostatic interaction between dyes and Si-C-N matrix, it exhibites high adsorption capacity and good regeneration and recycling ability for the dyes with triphenyl structure, such as methyl blue (MB), acid fuchsin (AF), basic fuchsin and malachite green. The adsorption process is determined by both surface adsorption and intraparticle diffusion. According to the Langmuir model, the adsorption capacity is 1327.7 mg·g(-1) and 1084.5 mg·g(-1) for MB and AF, respectively, which is much higher than that of many other adsorbents. On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red. Thus, the hierarchically porous Si-C-N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants.

  10. Hierarchically porous silicon-carbon-nitrogen hybrid materials towards highly efficient and selective adsorption of organic dyes

    Science.gov (United States)

    Meng, Lala; Zhang, Xiaofei; Tang, Yusheng; Su, Kehe; Kong, Jie

    2015-01-01

    The hierarchically macro/micro-porous silicon-carbon-nitrogen (Si-C-N) hybrid material was presented with novel functionalities of totally selective and highly efficient adsorption for organic dyes. The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates. Owing to the Van der Waals force between sp-hybridized carbon domains and triphenyl structure of dyes, and electrostatic interaction between dyes and Si-C-N matrix, it exhibites high adsorption capacity and good regeneration and recycling ability for the dyes with triphenyl structure, such as methyl blue (MB), acid fuchsin (AF), basic fuchsin and malachite green. The adsorption process is determined by both surface adsorption and intraparticle diffusion. According to the Langmuir model, the adsorption capacity is 1327.7 mg.g-1 and 1084.5 mg.g-1 for MB and AF, respectively, which is much higher than that of many other adsorbents. On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red. Thus, the hierarchically porous Si-C-N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants.

  11. Hierarchically porous silicon–carbon–nitrogen hybrid materials towards highly efficient and selective adsorption of organic dyes

    Science.gov (United States)

    Meng, Lala; Zhang, Xiaofei; Tang, Yusheng; Su, Kehe; Kong, Jie

    2015-01-01

    The hierarchically macro/micro-porous silicon–carbon–nitrogen (Si–C–N) hybrid material was presented with novel functionalities of totally selective and highly efficient adsorption for organic dyes. The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates. Owing to the Van der Waals force between sp2-hybridized carbon domains and triphenyl structure of dyes, and electrostatic interaction between dyes and Si-C-N matrix, it exhibites high adsorption capacity and good regeneration and recycling ability for the dyes with triphenyl structure, such as methyl blue (MB), acid fuchsin (AF), basic fuchsin and malachite green. The adsorption process is determined by both surface adsorption and intraparticle diffusion. According to the Langmuir model, the adsorption capacity is 1327.7 mg·g−1 and 1084.5 mg·g−1 for MB and AF, respectively, which is much higher than that of many other adsorbents. On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red. Thus, the hierarchically porous Si–C–N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants. PMID:25604334

  12. EFFECTS OF RESTRICTED BASILAR PAPILLAR LESIONS AND HAIR CELL REGENERATION ON AUDITORY FOREBRAIN FREQUENCY ORGANIZATION IN ADULT EUROPEAN STARLINGS

    Science.gov (United States)

    Irvine, Dexter R. F.; Brown, Mel; Kamke, Marc R.; Rubel, Edwin W

    2009-01-01

    The frequency organization of neurons in the forebrain Field L complex (FLC) of adult starlings was investigated to determine the effects of hair cell (HC) destruction in the basal portion of the basilar papilla (BP) and of subsequent HC regeneration. Conventional microelectrode mapping techniques were used in normal starlings and in lesioned starlings either 2 days or 6–10 weeks after aminoglycoside treatment. Histological examination of the BP and recordings of auditory brainstem evoked responses confirmed massive loss of HCs in the basal portion of the BP and hearing losses at frequencies above 2 kHz in starlings tested 2 days after aminoglycoside treatment. In these birds, all neurons in the region of the FLC in which CFs normally increase from 2 to 6 kHz had characteristic frequency (CF) in the range 2–4 kHz. The significantly elevated thresholds of responses in this region of altered tonotopic organization indicated that they were the residue of pre-lesion responses and did not reflect central nervous system plasticity. In the long-term recovery birds, there was histological evidence of substantial HC regeneration. The tonotopic organization of the high frequency region of the FLC did not differ from that in normal starlings, but the mean threshold at CF in this frequency range was intermediate between the values in the normal and lesioned short-recovery groups. The recovery of normal tonotopicity indicates considerable stability of the topography of neuronal connections in the avian auditory system, but the residual loss of sensitivity suggests deficiencies in high-frequency HC function. PMID:19474314

  13. Effects of restricted basilar papillar lesions and hair cell regeneration on auditory forebrain frequency organization in adult European starlings.

    Science.gov (United States)

    Irvine, Dexter R F; Brown, Mel; Kamke, Marc R; Rubel, Edwin W

    2009-05-27

    The frequency organization of neurons in the forebrain Field L complex (FLC) of adult starlings was investigated to determine the effects of hair cell (HC) destruction in the basal portion of the basilar papilla (BP) and of subsequent HC regeneration. Conventional microelectrode mapping techniques were used in normal starlings and in lesioned starlings either 2 d or 6-10 weeks after aminoglycoside treatment. Histological examination of the BP and recordings of auditory brainstem evoked responses confirmed massive loss of HCs in the basal portion of the BP and hearing losses at frequencies >2 kHz in starlings tested 2 d after aminoglycoside treatment. In these birds, all neurons in the region of the FLC in which characteristic frequencies (CFs) normally increase from 2 to 6 kHz had CF in the range of 2-4 kHz. The significantly elevated thresholds of responses in this region of altered tonotopic organization indicated that they were the residue of prelesion responses and did not reflect CNS plasticity. In the long-term recovery birds, there was histological evidence of substantial HC regeneration. The tonotopic organization of the high-frequency region of the FLC did not differ from that in normal starlings, but the mean threshold at CF in this frequency range was intermediate between the values in the normal and lesioned short-recovery groups. The recovery of normal tonotopicity indicates considerable stability of the topography of neuronal connections in the avian auditory system, but the residual loss of sensitivity suggests deficiencies in high-frequency HC function.

  14. Hierarchical organization in the temporal structure of infant-direct speech and song.

    Science.gov (United States)

    Falk, Simone; Kello, Christopher T

    2017-06-01

    Caregivers alter the temporal structure of their utterances when talking and singing to infants compared with adult communication. The present study tested whether temporal variability in infant-directed registers serves to emphasize the hierarchical temporal structure of speech. Fifteen German-speaking mothers sang a play song and told a story to their 6-months-old infants, or to an adult. Recordings were analyzed using a recently developed method that determines the degree of nested clustering of temporal events in speech. Events were defined as peaks in the amplitude envelope, and clusters of various sizes related to periods of acoustic speech energy at varying timescales. Infant-directed speech and song clearly showed greater event clustering compared with adult-directed registers, at multiple timescales of hundreds of milliseconds to tens of seconds. We discuss the relation of this newly discovered acoustic property to temporal variability in linguistic units and its potential implications for parent-infant communication and infants learning the hierarchical structures of speech and language. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. A Modulator-Induced Defect-Formation Strategy to Hierarchically Porous Metal-Organic Frameworks with High Stability.

    Science.gov (United States)

    Cai, Guorui; Jiang, Hai-Long

    2017-01-09

    The pore size enlargement and structural stability have been recognized as two crucial targets, which are rarely achieved together, in the development of metal-organic frameworks (MOFs). Herein, we have developed a versatile modulator-induced defect-formation strategy, in the presence of monocarboxylic acid as a modulator and an insufficient amount of organic ligand, successfully realizing the controllable synthesis of hierarchically porous MOFs (HP-MOFs) with high stability and tailorable pore characters. Remarkably, the integration of high stability and large mesoporous property enables these HP-MOFs to be important porous platforms for applications involving large molecules, especially in catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Land-use intensity and the effects of organic farming on biodiversity: a hierarchical meta-analysis.

    Science.gov (United States)

    Tuck, Sean L; Winqvist, Camilla; Mota, Flávia; Ahnström, Johan; Turnbull, Lindsay A; Bengtsson, Janne

    2014-06-01

    The benefits of organic farming to biodiversity in agricultural landscapes continue to be hotly debated, emphasizing the importance of precisely quantifying the effect of organic vs. conventional farming. We conducted an updated hierarchical meta-analysis of studies that compared biodiversity under organic and conventional farming methods, measured as species richness. We calculated effect sizes for 184 observations garnered from 94 studies, and for each study, we obtained three standardized measures reflecting land-use intensity. We investigated the stability of effect sizes through time, publication bias due to the 'file drawer' problem, and consider whether the current literature is representative of global organic farming patterns. On average, organic farming increased species richness by about 30%. This result has been robust over the last 30 years of published studies and shows no sign of diminishing. Organic farming had a greater effect on biodiversity as the percentage of the landscape consisting of arable fields increased, that is, it is higher in intensively farmed regions. The average effect size and the response to agricultural intensification depend on taxonomic group, functional group and crop type. There is some evidence for publication bias in the literature; however, our results are robust to its impact. Current studies are heavily biased towards northern and western Europe and North America, while other regions with large areas of organic farming remain poorly investigated. Synthesis and applications. Our analysis affirms that organic farming has large positive effects on biodiversity compared with conventional farming, but that the effect size varies with the organism group and crop studied, and is greater in landscapes with higher land-use intensity. Decisions about where to site organic farms to maximize biodiversity will, however, depend on the costs as well as the potential benefits. Current studies have been heavily biased towards

  17. Carbon-cryogel hierarchical composites as effective and scalable filters for removal of trace organic pollutants from water.

    Science.gov (United States)

    Busquets, Rosa; Ivanov, Alexander E; Mbundi, Lubinda; Hörberg, Sofia; Kozynchenko, Oleksandr P; Cragg, Peter J; Savina, Irina N; Whitby, Raymond L D; Mikhalovsky, Sergey V; Tennison, Stephen R; Jungvid, Hans; Cundy, Andrew B

    2016-11-01

    Effective technologies are required to remove organic micropollutants from large fluid volumes to overcome present and future challenges in water and effluent treatment. A novel hierarchical composite filter material for rapid and effective removal of polar organic contaminants from water was developed. The composite is fabricated from phenolic resin-derived carbon microbeads with controllable porous structure and specific surface area embedded in a monolithic, flow permeable, poly(vinyl alcohol) cryogel. The bead-embedded monolithic composite filter retains the bulk of the high adsorptive capacity of the carbon microbeads while improving pore diffusion rates of organic pollutants. Water spiked with organic contaminants, both at environmentally relevant concentrations and at high levels of contamination, was used to determine the purification limits of the filter. Flow through tests using water spiked with the pesticides atrazine (32 mg/L) and malathion (16 mg/L) indicated maximum adsorptive capacities of 641 and 591 mg pollutant/g carbon, respectively. Over 400 bed volumes of water contaminated with 32 mg atrazine/L, and over 27,400 bed volumes of water contaminated with 2 μg atrazine/L, were treated before pesticide guideline values of 0.1 μg/L were exceeded. High adsorptive capacity was maintained when using water with high total organic carbon (TOC) levels and high salinity. The toxicity of water filtrates was tested in vitro with human epithelial cells with no evidence of cytotoxicity after initial washing.

  18. Thermally Stable Metal-Organic Framework-Templated Synthesis of Hierarchically Porous Metal Sulfides: Enhanced Photocatalytic Hydrogen Production.

    Science.gov (United States)

    Xiao, Juan-Ding; Jiang, Hai-Long

    2017-07-01

    Porous nanostructured materials are demonstrated to be very promising in catalysis due to their well accessible active sites. Thermally stable metal-organic frameworks (MOFs) as hard templates are successfully utilized to afford porous metal oxides and subsequently metal sulfides by a nanocasting method. The resultant metal oxides/sulfides show considerable Brunauer-Emmett-Teller (BET) surface areas, by partially inheriting the pore character of MOF templates. Preliminary investigation on the obtained hierarchically porous CdS for water splitting, as a proof of concept, demonstrates its much higher activity than both corresponding bulk and nanosized counterparts, under visible light irradiation. Given the structural diversity and tailorability of MOFs, such synthetic approach may open an avenue to the synthesis of advanced porous materials for functional applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Metal-Organic Framework Derived Hierarchically Porous Nitrogen-Doped Carbon Nanostructures as Novel Electrocatalyst for Oxygen Reduction Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Shaofang; Zhu, Chengzhou; Zhou, Yazhou; Yang, Guohai; Jeon, Ju Won; Lemmon, John P.; Du, Dan; Nune, Satish K.; Lin, Yuehe

    2015-10-01

    The hierarchically porous nitrogen-doped carbon materials, derived from nitrogen-containing isoreticular metal-organic framework-3 (IRMOF-3) through direct carbonization, exhibited excellent electrocatalytic activity in alkaline solution for oxygen reduction reaction (ORR). This high activity is attributed to the 10 presence of high percentage of quaternary and pyridinic nitrogen, the high surface area as well as good conductivity. When IRMOF-3 was carbonized at 950 °C (CIRMOF-3-950), it showed four-electron reduction pathway for ORR and exhibited better stability (about 78.5% current density was maintained) than platinum/carbon (Pt/C) in the current durability test. In addition, CIRMOF-3-950 presented high selectivity to cathode reactions compared to commercial Pt/C.

  20. Hierarchically structured ZnO-graphene hollow microspheres towards effective reusable adsorbent for organic pollutant via photodegradation process

    Energy Technology Data Exchange (ETDEWEB)

    Bera, Susanta; Pal, Moumita; Naskar, Atanu; Jana, Sunirmal, E-mail: sjana@cgcri.res.in

    2016-06-05

    Present work reports on successful synthesis of hierarchical hollow microspheres (HHM) from ZnO-chemically converted graphene (CCG) nanocomposites by adopting low-temperature surfactant/template free solution method, varying graphene oxide (GO) to zinc acetate dihydrate weight ratio (R = 0.00, 0.01, 0.032, 0.063) in the precursors. It is found that the HHM consist of self-assembled ZnO nanoparticles, chemically interacted with CCG as evidenced from structural characterizations (X-ray diffraction, field emission scanning and transmission electron microscopes) with UV–Vis, FTIR, Raman and X-ray photoelectron spectroscopies. Multipoint BET nitrogen adsorption–desorption isotherms of ZG30, synthesized using an optimum GO content (R = 0.032) showed relatively high specific surface area. The sample showed significantly improved adsorption capacity of rhodamine B dye (as water pollutant) compare to pristine ZnO (R = 0.0) as well as commercially available P25 (TiO{sub 2}). The ZG30 functioned as reusable adsorbent due to its highly efficient photocatalytic activity under UV (λ, 254 nm) irradiation. Methyl orange and phenol were also used to check the effectiveness of ZG30 for permanent cleaning of the pollutants. This facile process could create an avenue for synthesis of hollow microspheres from different metal oxide semiconductor–graphene nanocomposites for efficient and reusable adsorbent of water soluble organic pollutants. - Graphical abstract: Hierarchical hollow microspheres from ZnO-graphene nanocomposites as reusable adsorbent of organic water pollutant. - Highlights: • Prepared hollow microspheres of ZnO-graphene nanocomposite (ZG) by solution route. • By optimizing graphene content, ZG shows improved adsorption capacity of dyes. • ZG shows a highly efficient photocatalytic activity of the dye pollutants. • It acts as a reusable adsorbent of the pollutants.

  1. Hierarchical organization of the coordinative structure of the skill of clay kneading.

    Science.gov (United States)

    Yamamoto, Tomoyuki; Fujinami, Tsutomu

    2008-10-01

    An experiment was conducted to study the skill of clay kneading in pottery. This task usually requires a few years to master and is therefore well suited to study the long-term development of a complex motor skill. Participants' kneading movements were measured in 3D using a motion capture device and phase relations among coordinates and joint angles were analyzed in terms of the mutual phase relative to a reference point using the Hilbert transform. While a certain degree of periodicity was observed in all 10 participants, the behavior of the experts was characterized by a significant delay for the right elbow (i.e., the pushing arm) and the fore-aft position of the upper torso and only brief delays for the other parts, which all tended to synchronize with the reference. These findings are consistent with our notion of "differentiation within coordination", according to which skill learning proceeds in a hierarchical manner in that coordination among limb movements is established first, followed by modulations of specific limb movements within the established coordination. Although this feature of expert behavior was also apparent in our previous studies of clay kneading and samba shaking and dancing, the numbers of participants in those studies were not sufficient to draw firm conclusions. Since the present study involved more participants and a superior method of analysis, the present evidence for the principle of differentiation within coordination is more conclusive.

  2. The hierarchical organization of semantic memory: executive function in the processing of superordinate concepts.

    Science.gov (United States)

    Raposo, Ana; Mendes, Mafalda; Marques, J Frederico

    2012-01-16

    Research on the processing of objects at different hierarchical levels has suggested that understanding superordinate concepts (e.g. fruit), relative to basic level concepts (e.g. apple), requires greater semantic control demands. Yet, it is unclear which factors underlie this difference in executive processing. We built on previous research showing that superordinate concepts have less shared features among their members and therefore may involve higher semantic control requirements. To test this hypothesis, we developed an fMRI study in which we orthogonally manipulated feature sharedness (more shared vs. less shared) and concept level (superordinate vs. basic) in a sentence verification task. Sentences involving less shared features, relative to more shared features, significantly engaged the L lateral PFC. Importantly, sentences that included superordinate concepts, relative to those with basic level concepts, also revealed a stronger response in L lateral PFC, along with posterior temporal gyrus activation. There was also a significant interaction between feature sharedness and concept level in several PFC regions and L posterior temporal areas. The results suggest that relative to basic level concepts, processing superordinate concepts requires extra semantic control in L lateral PFC to coordinate information that is less shared by other members of the category level. These findings demonstrate that feature sharedness impacts the neural basis of semantic knowledge, and is a critical dimension in the processing of superordinate concepts.

  3. Hey2 functions in parallel with Hes1 and Hes5 for mammalian auditory sensory organ development

    Directory of Open Access Journals (Sweden)

    Chin Michael T

    2008-02-01

    Full Text Available Abstract Background During mouse development, the precursor cells that give rise to the auditory sensory organ, the organ of Corti, are specified prior to embryonic day 14.5 (E14.5. Subsequently, the sensory domain is patterned precisely into one row of inner and three rows of outer sensory hair cells interdigitated with supporting cells. Both the restriction of the sensory domain and the patterning of the sensory mosaic of the organ of Corti involve Notch-mediated lateral inhibition and cellular rearrangement characteristic of convergent extension. This study explores the expression and function of a putative Notch target gene. Results We report that a putative Notch target gene, hairy-related basic helix-loop-helix (bHLH transcriptional factor Hey2, is expressed in the cochlear epithelium prior to terminal differentiation. Its expression is subsequently restricted to supporting cells, overlapping with the expression domains of two known Notch target genes, Hairy and enhancer of split homolog genes Hes1 and Hes5. In combination with the loss of Hes1 or Hes5, genetic inactivation of Hey2 leads to increased numbers of mis-patterned inner or outer hair cells, respectively. Surprisingly, the ectopic hair cells in Hey2 mutants are accompanied by ectopic supporting cells. Furthermore, Hey2-/-;Hes1-/- and Hey2-/-;Hes1+/- mutants show a complete penetrance of early embryonic lethality. Conclusion Our results indicate that Hey2 functions in parallel with Hes1 and Hes5 in patterning the organ of Corti, and interacts genetically with Hes1 for early embryonic development and survival. Our data implicates expansion of the progenitor pool and/or the boundaries of the developing sensory organ to account for patterning defects observed in Hey2 mutants.

  4. Activity in a premotor cortical nucleus of zebra finches is locally organized and exhibits auditory selectivity in neurons but not in glia.

    Directory of Open Access Journals (Sweden)

    Michael H Graber

    Full Text Available Motor functions are often guided by sensory experience, most convincingly illustrated by complex learned behaviors. Key to sensory guidance in motor areas may be the structural and functional organization of sensory inputs and their evoked responses. We study sensory responses in large populations of neurons and neuron-assistive cells in the songbird motor area HVC, an auditory-vocal brain area involved in sensory learning and in adult song production. HVC spike responses to auditory stimulation display remarkable preference for the bird's own song (BOS compared to other stimuli. Using two-photon calcium imaging in anesthetized zebra finches we measure the spatio-temporal structure of baseline activity and of auditory evoked responses in identified populations of HVC cells. We find strong correlations between calcium signal fluctuations in nearby cells of a given type, both in identified neurons and in astroglia. In identified HVC neurons only, auditory stimulation decorrelates ongoing calcium signals, less for BOS than for other sound stimuli. Overall, calcium transients show strong preference for BOS in identified HVC neurons but not in astroglia, showing diversity in local functional organization among identified neuron and astroglia populations.

  5. An in situ self-assembly template strategy for the preparation of hierarchical-pore metal-organic frameworks

    Science.gov (United States)

    Huang, Hongliang; Li, Jian-Rong; Wang, Keke; Han, Tongtong; Tong, Minman; Li, Liangsha; Xie, Yabo; Yang, Qingyuan; Liu, Dahuan; Zhong, Chongli

    2015-01-01

    Metal-organic frameworks (MOFs) have recently emerged as a new type of nanoporous materials with tailorable structures and functions. Usually, MOFs have uniform pores smaller than 2 nm in size, limiting their practical applications in some cases. Although a few approaches have been adopted to prepare MOFs with larger pores, it is still challenging to synthesize hierarchical-pore MOFs (H-MOFs) with high structural controllability and good stability. Here we demonstrate a facile and versatile method, an in situ self-assembly template strategy for fabricating stable H-MOFs, in which multi-scale soluble and/or acid-sensitive metal-organic assembly (MOA) fragments form during the reactions between metal ions and organic ligands (to construct MOFs), and act as removable dynamic chemical templates. This general strategy was successfully used to prepare various H-MOFs that show rich porous properties and potential applications, such as in large molecule adsorption. Notably, the mesopore sizes of the H-MOFs can be tuned by varying the amount of templates. PMID:26548441

  6. In-Situ Formed Hierarchical Metal-Organic Flexible Cathode for High-Energy Sodium-Ion Batteries.

    Science.gov (United States)

    Huang, Ying; Fang, Chun; Zeng, Rui; Liu, Yaojun; Zhang, Wang; Wang, Yanjie; Liu, Qingju; Huang, Yunhui

    2017-09-10

    Metal-organic compounds are a family of electrode materials with structural diversity and excellent thermal stability for rechargeable batteries. Here, we fabricate a hierarchical nanocomposite with metal-organic cuprous tetracyanoquino- dimethane (CuTCNQ) in three-dimensional (3D) conductive carbon nanofibers (CNFs) network by in-situ growth, and evaluate it as flexible cathode for sodium-ion batteries (SIBs). CuTCNQ in such flexible composite electrode is able to exhibit a superhigh capacity of 252 mAh g-1 at 0.1 C and highly reversible stability for 1200 cycles within the voltage range of 2.5 - 4.1 V (vs. Na+/Na). A high specific energy of 762 Wh kg-1 is obtained with high average potential of 3.2 V (vs. Na+/Na). The in-situ formed electroactive metal-organic composites with tailored nanoarchitecture provide a promising alternative choice for high-performance cathode materials in sodium-ion batteries with high energy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Principal Covariates Clusterwise Regression (PCCR): Accounting for Multicollinearity and Population Heterogeneity in Hierarchically Organized Data.

    Science.gov (United States)

    Wilderjans, Tom Frans; Vande Gaer, Eva; Kiers, Henk A L; Van Mechelen, Iven; Ceulemans, Eva

    2017-03-01

    In the behavioral sciences, many research questions pertain to a regression problem in that one wants to predict a criterion on the basis of a number of predictors. Although in many cases, ordinary least squares regression will suffice, sometimes the prediction problem is more challenging, for three reasons: first, multiple highly collinear predictors can be available, making it difficult to grasp their mutual relations as well as their relations to the criterion. In that case, it may be very useful to reduce the predictors to a few summary variables, on which one regresses the criterion and which at the same time yields insight into the predictor structure. Second, the population under study may consist of a few unknown subgroups that are characterized by different regression models. Third, the obtained data are often hierarchically structured, with for instance, observations being nested into persons or participants within groups or countries. Although some methods have been developed that partially meet these challenges (i.e., principal covariates regression (PCovR), clusterwise regression (CR), and structural equation models), none of these methods adequately deals with all of them simultaneously. To fill this gap, we propose the principal covariates clusterwise regression (PCCR) method, which combines the key idea's behind PCovR (de Jong & Kiers in Chemom Intell Lab Syst 14(1-3):155-164, 1992) and CR (Späth in Computing 22(4):367-373, 1979). The PCCR method is validated by means of a simulation study and by applying it to cross-cultural data regarding satisfaction with life.

  8. Auditory agnosia.

    Science.gov (United States)

    Slevc, L Robert; Shell, Alison R

    2015-01-01

    Auditory agnosia refers to impairments in sound perception and identification despite intact hearing, cognitive functioning, and language abilities (reading, writing, and speaking). Auditory agnosia can be general, affecting all types of sound perception, or can be (relatively) specific to a particular domain. Verbal auditory agnosia (also known as (pure) word deafness) refers to deficits specific to speech processing, environmental sound agnosia refers to difficulties confined to non-speech environmental sounds, and amusia refers to deficits confined to music. These deficits can be apperceptive, affecting basic perceptual processes, or associative, affecting the relation of a perceived auditory object to its meaning. This chapter discusses what is known about the behavioral symptoms and lesion correlates of these different types of auditory agnosia (focusing especially on verbal auditory agnosia), evidence for the role of a rapid temporal processing deficit in some aspects of auditory agnosia, and the few attempts to treat the perceptual deficits associated with auditory agnosia. A clear picture of auditory agnosia has been slow to emerge, hampered by the considerable heterogeneity in behavioral deficits, associated brain damage, and variable assessments across cases. Despite this lack of clarity, these striking deficits in complex sound processing continue to inform our understanding of auditory perception and cognition. © 2015 Elsevier B.V. All rights reserved.

  9. Principal component analysis vs. self-organizing maps combined with hierarchical clustering for pattern recognition in volcano seismic spectra

    Science.gov (United States)

    Unglert, K.; Radić, V.; Jellinek, A. M.

    2016-06-01

    Variations in the spectral content of volcano seismicity related to changes in volcanic activity are commonly identified manually in spectrograms. However, long time series of monitoring data at volcano observatories require tools to facilitate automated and rapid processing. Techniques such as self-organizing maps (SOM) and principal component analysis (PCA) can help to quickly and automatically identify important patterns related to impending eruptions. For the first time, we evaluate the performance of SOM and PCA on synthetic volcano seismic spectra constructed from observations during two well-studied eruptions at Klauea Volcano, Hawai'i, that include features observed in many volcanic settings. In particular, our objective is to test which of the techniques can best retrieve a set of three spectral patterns that we used to compose a synthetic spectrogram. We find that, without a priori knowledge of the given set of patterns, neither SOM nor PCA can directly recover the spectra. We thus test hierarchical clustering, a commonly used method, to investigate whether clustering in the space of the principal components and on the SOM, respectively, can retrieve the known patterns. Our clustering method applied to the SOM fails to detect the correct number and shape of the known input spectra. In contrast, clustering of the data reconstructed by the first three PCA modes reproduces these patterns and their occurrence in time more consistently. This result suggests that PCA in combination with hierarchical clustering is a powerful practical tool for automated identification of characteristic patterns in volcano seismic spectra. Our results indicate that, in contrast to PCA, common clustering algorithms may not be ideal to group patterns on the SOM and that it is crucial to evaluate the performance of these tools on a control dataset prior to their application to real data.

  10. Optimizing the imaging of the monkey auditory cortex: sparse vs. continuous fMRI.

    Science.gov (United States)

    Petkov, Christopher I; Kayser, Christoph; Augath, Mark; Logothetis, Nikos K

    2009-10-01

    The noninvasive imaging of the monkey auditory system with functional magnetic resonance imaging (fMRI) can bridge the gap between electrophysiological studies in monkeys and imaging studies in humans. Some of the recent imaging of monkey auditory cortical and subcortical structures relies on a technique of "sparse imaging," which was developed in human studies to sidestep the negative influence of scanner noise by adding periods of silence in between volume acquisition. Among the various aspects that have gone into the ongoing optimization of fMRI of the monkey auditory cortex, replacing the more common continuous-imaging paradigm with sparse imaging seemed to us to make the most obvious difference in the amount of activity that we could reliably obtain from awake or anesthetized animals. Here, we directly compare the sparse- and continuous-imaging paradigms in anesthetized animals. We document a strikingly greater auditory response with sparse imaging, both quantitatively and qualitatively, which includes a more expansive and robust tonotopic organization. There were instances where continuous imaging could better reveal organizational properties that sparse imaging missed, such as aspects of the hierarchical organization of auditory cortex. We consider the choice of imaging paradigm as a key component in optimizing the fMRI of the monkey auditory cortex.

  11. Immobilization of Bacillus subtilis lipase on a Cu-BTC based hierarchically porous metal-organic framework material: a biocatalyst for esterification.

    Science.gov (United States)

    Cao, Yu; Wu, Zhuofu; Wang, Tao; Xiao, Yu; Huo, Qisheng; Liu, Yunling

    2016-04-28

    Bacillus subtilis lipase (BSL2) has been successfully immobilized into a Cu-BTC based hierarchically porous metal-organic framework material for the first time. The Cu-BTC hierarchically porous MOF material with large mesopore apertures is prepared conveniently by using a template-free strategy under mild conditions. The immobilized BSL2 presents high enzymatic activity and perfect reusability during the esterification reaction. After 10 cycles, the immobilized BSL2 still exhibits 90.7% of its initial enzymatic activity and 99.6% of its initial conversion.

  12. Metal organic framework synthesis in the presence of surfactants: towards hierarchical MOFs?

    NARCIS (Netherlands)

    Seoane, B.; Dikhtiarenko, A.; Mayoral, A.; Tellez, C.; Coronas,J.; Kapteijn, F.; Gascon, J.

    2015-01-01

    The effect of synthesis pH and H2O/EtOH molar ratio on the textural properties of different aluminium trimesate metal organic frameworks (MOFs) prepared in the presence of the well-known cationic surfactant cetyltrimethylammonium bromide (CTAB) at 120 °C was studied with the purpose of obtaining a

  13. HIERARCHICAL DOCUMENT ORGANIZATION AND RETRIEVAL BASED ON THEMES FOR NEWS TRACKS

    Directory of Open Access Journals (Sweden)

    S. M. Arnica Sowmi

    2013-12-01

    Full Text Available Organizing text documents is an important task and there are also numbers of strategies available in it. A good document clustering approach can assist computers in organizing the document corpus automatically into a meaningful cluster hierarchy for efficient browsing and navigation, which is very valuable for overcoming the deficiencies of traditional information retrieval methods. By clustering the text documents, the documents sharing the same topic are grouped together. Unlike document classification, no labelled documents are provided in clustering. Hence clustering is also known as unsupervised learning. In case of term based data retrieval, time consumption problem prevails. This is because as for each term, the data set’s has to be retrieved. Hence we are going for taxonomy based data retrieval. This paper presents the taxonomical approach of clustering data set in a dynamic environment. It is a difficult task to cluster data in a dynamic environment. But this can be made easily by using RSS feeds.

  14. The E3 ligase Ubr3 regulates Usher syndrome and MYH9 disorder proteins in the auditory organs of Drosophila and mammals

    Science.gov (United States)

    Li, Tongchao; Giagtzoglou, Nikolaos; Eberl, Daniel F; Jaiswal, Sonal Nagarkar; Cai, Tiantian; Godt, Dorothea; Groves, Andrew K; Bellen, Hugo J

    2016-01-01

    Myosins play essential roles in the development and function of auditory organs and multiple myosin genes are associated with hereditary forms of deafness. Using a forward genetic screen in Drosophila, we identified an E3 ligase, Ubr3, as an essential gene for auditory organ development. Ubr3 negatively regulates the mono-ubiquitination of non-muscle Myosin II, a protein associated with hearing loss in humans. The mono-ubiquitination of Myosin II promotes its physical interaction with Myosin VIIa, a protein responsible for Usher syndrome type IB. We show that ubr3 mutants phenocopy pathogenic variants of Myosin II and that Ubr3 interacts genetically and physically with three Usher syndrome proteins. The interactions between Myosin VIIa and Myosin IIa are conserved in the mammalian cochlea and in human retinal pigment epithelium cells. Our work reveals a novel mechanism that regulates protein complexes affected in two forms of syndromic deafness and suggests a molecular function for Myosin IIa in auditory organs. DOI: http://dx.doi.org/10.7554/eLife.15258.001 PMID:27331610

  15. Auditory pathways: anatomy and physiology.

    Science.gov (United States)

    Pickles, James O

    2015-01-01

    This chapter outlines the anatomy and physiology of the auditory pathways. After a brief analysis of the external, middle ears, and cochlea, the responses of auditory nerve fibers are described. The central nervous system is analyzed in more detail. A scheme is provided to help understand the complex and multiple auditory pathways running through the brainstem. The multiple pathways are based on the need to preserve accurate timing while extracting complex spectral patterns in the auditory input. The auditory nerve fibers branch to give two pathways, a ventral sound-localizing stream, and a dorsal mainly pattern recognition stream, which innervate the different divisions of the cochlear nucleus. The outputs of the two streams, with their two types of analysis, are progressively combined in the inferior colliculus and onwards, to produce the representation of what can be called the "auditory objects" in the external world. The progressive extraction of critical features in the auditory stimulus in the different levels of the central auditory system, from cochlear nucleus to auditory cortex, is described. In addition, the auditory centrifugal system, running from cortex in multiple stages to the organ of Corti of the cochlea, is described.

  16. Shape-tailored polymer colloids on the road to become structural motifs for hierarchically organized materials.

    Science.gov (United States)

    Plüisch, Claudia Simone; Wittemann, Alexander

    2013-12-01

    Anisometric polymer colloids are likely to behave differently when compared with centrosymmetric particles. Their study may not only shine new light on the organization of matter; they may also serve as building units with specific symmetries and complexity to build new materials from them. Polymer colloids of well-defined complex geometries can be obtained by packing a limited number of spherical polymer particles into clusters with defined configurations. Such supracolloidal architectures can be fabricated at larger scales using narrowly dispersed emulsion droplets as templates. Assemblies built from at least two different types of particles as elementary building units open perspectives in selective targeting of colloids with specific properties, aiming for mesoscale building blocks with tailor-made morphologies and multifunctionality. Polymer colloids with defined geometries are also ideal to study shape-dependent properties such as the diffusion of complex particles. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Modularity and hierarchical organization of action programs in children's acquisition of graphic skills.

    Science.gov (United States)

    Manoel, Edison de J; Dantas, Luiz; Gimenez, Roberto; de Oliveira, Dalton Lustosa

    2011-10-01

    The organization of actions is based on modules in memory as a result of practice, easing the demand of performing more complex actions. If this modularization occurs, the elements of the module must remain invariant in new tasks. To test this hypothesis, 35 children, age 10 yr., practiced a graphic criterion task on a digital tablet and completed a complex graphic task enclosing the previous one. Total movement and pause times to draw the figure indicated skill acquisition. A module was identified by the variability of relative timing, pause time, and sequencing. Total movement to perform the criterion task did not increase significantly when it was embedded in the more complex task. Modularity was evidenced by the stability of relative timing and pause time and sequencing. The spatial position of new elements did not perturb the module, so the grammar of action may still have been forming.

  18. K-shell decomposition reveals hierarchical cortical organization of the human brain

    Science.gov (United States)

    Lahav, Nir; Ksherim, Baruch; Ben-Simon, Eti; Maron-Katz, Adi; Cohen, Reuven; Havlin, Shlomo

    2016-08-01

    In recent years numerous attempts to understand the human brain were undertaken from a network point of view. A network framework takes into account the relationships between the different parts of the system and enables to examine how global and complex functions might emerge from network topology. Previous work revealed that the human brain features ‘small world’ characteristics and that cortical hubs tend to interconnect among themselves. However, in order to fully understand the topological structure of hubs, and how their profile reflect the brain’s global functional organization, one needs to go beyond the properties of a specific hub and examine the various structural layers that make up the network. To address this topic further, we applied an analysis known in statistical physics and network theory as k-shell decomposition analysis. The analysis was applied on a human cortical network, derived from MRI\\DSI data of six participants. Such analysis enables us to portray a detailed account of cortical connectivity focusing on different neighborhoods of inter-connected layers across the cortex. Our findings reveal that the human cortex is highly connected and efficient, and unlike the internet network contains no isolated nodes. The cortical network is comprised of a nucleus alongside shells of increasing connectivity that formed one connected giant component, revealing the human brain’s global functional organization. All these components were further categorized into three hierarchies in accordance with their connectivity profile, with each hierarchy reflecting different functional roles. Such a model may explain an efficient flow of information from the lowest hierarchy to the highest one, with each step enabling increased data integration. At the top, the highest hierarchy (the nucleus) serves as a global interconnected collective and demonstrates high correlation with consciousness related regions, suggesting that the nucleus might serve as a

  19. Synthesis of hierarchical porous carbon monoliths with incorporated metal-organic frameworks for enhancing volumetric based CO₂ capture capability.

    Science.gov (United States)

    Qian, Dan; Lei, Cheng; Hao, Guang-Ping; Li, Wen-Cui; Lu, An-Hui

    2012-11-01

    This work aims to optimize the structural features of hierarchical porous carbon monolith (HCM) by incorporating the advantages of metal-organic frameworks (MOFs) (Cu₃(BTC)₂) to maximize the volumetric based CO₂ capture capability (CO₂ capacity in cm³ per cm³ adsorbent), which is seriously required for the practical application of CO₂ capture. The monolithic HCM was used as a matrix, in which Cu₃(BTC)₂ was in situ synthesized, to form HCM-Cu₃(BTC)₂ composites by a step-by-step impregnation and crystallization method. The resulted HCM-Cu₃(BTC)₂ composites, which retain the monolithic shape and exhibit unique hybrid structure features of both HCM and Cu₃(BTC)₂, show high CO₂ uptake of 22.7 cm³ cm⁻³ on a volumetric basis. This value is nearly as twice as the uptake of original HCM. The dynamic gas separation measurement of HCM-Cu₃(BTC)₂, using 16% (v/v) CO₂ in N₂ as feedstock, illustrates that CO₂ can be easily separated from N₂ under the ambient conditions and achieves a high separation factor for CO₂ over N₂, ranging from 67 to 100, reflecting a strongly competitive CO₂ adsorption by the composite. A facile CO₂ release can be realized by purging an argon flow through the fixed-bed adsorber at 25 °C, indicating the good regeneration ability.

  20. Metal organic framework derived magnetically separable 3-dimensional hierarchical Ni@C nanocomposites: Synthesis and adsorption properties

    Science.gov (United States)

    Song, Yixuan; Qiang, Tingting; Ye, Ming; Ma, Qiuyang; Fang, Zhen

    2015-12-01

    Design an effective absorbent that has high surface area, and perfect recyclable is imperative for pollution elimination. Herein, we report a facile two-step strategy to fabricate magnetically separable 3-dimensional (3D) hierarchical carbon-coated nickel (Ni@C) nanocomposites by calcinating nickel based metal organic framework (Ni3(OH)2(C8H4O4)2(H2O)4). SEM and TEM images illuminate that the nanocomposites were constructed by 8 nm nickel nanoparticle encapsulated in 3D flake like carbon. The specific surface area of the obtained nanocomposites is up to 120.38 m2 g-1. Room temperature magnetic measurement indicates the nanocomposites show soft magnetism property, which endows the nanocomposites with an ideal fast magnetic separable property. The maximum adsorption capacity of the nanocomposites for rhodamine B is 84.5 mg g-1. Furthermore, the nanocomposites also exhibit a high adsorption capacity for heavy metal ions. The adsorbent can be very easily separated from the solution by using a common magnet without exterior energy. The as-prepared Ni@C nanocomposites can apply in waste water treatment on a large-scale as a new adsorbent with high efficiency and excellent recyclability.

  1. Template-free solvothermal synthesis of hierarchical boehmite hollow microspheres with strong affinity toward organic pollutants in water

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Weiquan, E-mail: caiwq@whut.edu.cn [School of Chemical Engineering, Wuhan University of Technology, Luoshi Road 205, Wuhan 430070 (China); Chen, Shuanggui [School of Chemical Engineering, Wuhan University of Technology, Luoshi Road 205, Wuhan 430070 (China); Yu, Jiaguo, E-mail: jiaguoyu@yahoo.com [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China); Hu, Yuzhen; Dang, Chengxiong [School of Chemical Engineering, Wuhan University of Technology, Luoshi Road 205, Wuhan 430070 (China); Ma, Shuhua [Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2013-02-15

    Three-dimensional hierarchical boehmite hollow microspheres with a very high yield at low cost were successfully synthesized via a one-pot template-free solvothermal route using aluminum chloride hexahydrate as precursor in a mixed ethanol–water solution with assistance of trisodium citrate. The as-synthesized products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption/desorption techniques. The results show that Cl{sup −} and addition amount of trisodium citrate have significant effect on the morphologies of the resultant products, and 6–8 mmol of trisodium citrate is optimal for the synthesis of boehmite hollow microspheres assembled from randomly interconnecting and aligned nanorods with solvothermal time no less than 15 h. A synergistic mediation mechanism of citrate ions and Cl{sup −} to form boehmite hollow spheres via self-assembly morphology evolution was proposed based on the experimental results. Interestingly, the typical boehmite hollow microspheres with a surface area of 102 m{sup 2} g{sup −1}, pore volume of 0.37 cm3 g{sup −1}, and the average pore size of 14.6 nm show superb adsorption properties for Congo red with maximum capacity of 114.7 mg g{sup −1} which is higher than that of a commercial boehmite. This simple synthetic route is a very promising way for the design and synthesis of new functional hierarchical nanostructured materials with desired adsorptive properties. - Graphical abstract: Boehmite hollow microspheres with strong affinity toward organic pollutants were successfully synthesized via a one-pot template-free solvothermal route using AlCl{sub 3}·6H{sub 2}O as aluminum precursor in a mixed ethanol–water solution with assistance of trisodium citrate, and its adsorption performance toward Congo red is much higher than that of the commercial boehmite powder due to its unique hollow structure. Highlights: ► Boehmite

  2. University Organization Reform: Hierarchical Organization Structure and Communication of Organizations%高校组织改革中的科层组织结构和组织沟通

    Institute of Scientific and Technical Information of China (English)

    王志敏; 张红梅

    2012-01-01

    利用科层组织管理的优势,同时在高校管理组织机构中建立组织沟通制度,让两种管理模式互补,可以提高组织效能,加强高校内部学术权力与行政权力的沟通与平衡,完善整个组织的管理体制。%In university management organizations, communication system of organizations should be established by using the advantage of management of hierarchical organizations. As the two management modes are complementary, the organizational effectiveness can be improved to strengthen the communication and balance between internal academic authorities and administrative powers, so as to perfect the whole organization' s management system.

  3. Auditory hallucinations.

    Science.gov (United States)

    Blom, Jan Dirk

    2015-01-01

    Auditory hallucinations constitute a phenomenologically rich group of endogenously mediated percepts which are associated with psychiatric, neurologic, otologic, and other medical conditions, but which are also experienced by 10-15% of all healthy individuals in the general population. The group of phenomena is probably best known for its verbal auditory subtype, but it also includes musical hallucinations, echo of reading, exploding-head syndrome, and many other types. The subgroup of verbal auditory hallucinations has been studied extensively with the aid of neuroimaging techniques, and from those studies emerges an outline of a functional as well as a structural network of widely distributed brain areas involved in their mediation. The present chapter provides an overview of the various types of auditory hallucination described in the literature, summarizes our current knowledge of the auditory networks involved in their mediation, and draws on ideas from the philosophy of science and network science to reconceptualize the auditory hallucinatory experience, and point out directions for future research into its neurobiologic substrates. In addition, it provides an overview of known associations with various clinical conditions and of the existing evidence for pharmacologic and non-pharmacologic treatments.

  4. cDNA cloning, tissue distribution, and chromosomal localization of Ocp2, a gene encoding a putative transcription-associated factor predominantly expressed in the auditory organs

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hong; Thalmann, I.; Thalmann, R. [Washington Univ., St. Louis, MO (United States)] [and others

    1995-06-10

    We report the cloning of the Ocp2 gene encoding OCP-II from a guinea pig organ-of-Corti cDNA library. The predicted open reading frame encodes a protein of 163 amino acids with an estimated molecular mass of 18.6 kDa. A homology search revealed that Ocp2 shares significant sequence similarity with p15, a sub-unit of transcription factor SIII that regulates the activity of the RNA polymerase II elongation complex. The Ocp2 messenger RNA is expressed abundantly in the cochlea while not significantly in any other tissues examined, including brain, eye, heart, intestine, kidney, liver, lung, thigh muscle, and testis, demonstrating that the expression of this gene may be restricted to auditory organs. A polyclonal antiserum was raised against the N-terminal region of OCP-II. Immunohistochemical staining of paraffin-embedded sections of the cochlea showed that OCP-II is localized abundantly in nonsensory cells in the organ of Corti; in addition, it was also detected, at a lower concentration, in vestibular sensory organs, as well as auditory and vestibular brain stem nuclei. The Ocp2 gene was mapped to mouse chromosome 4 as well as 11. Our results suggest that OCP-II may be involved in transcription regulation for the development or maintenance of specialized functions of the inner ear. 40 refs., 5 figs.

  5. The role of the auditory brainstem in processing musically-relevant pitch

    Directory of Open Access Journals (Sweden)

    Gavin M. Bidelman

    2013-05-01

    Full Text Available Neuroimaging work has shed light on the cerebral architecture involved in processing the melodic and harmonic aspects of music. Here, recent evidence is reviewed illustrating that subcortical auditory structures contribute to the early formation and processing of musically-relevant pitch. Electrophysiological recordings from the human brainstem and population responses from the auditory nerve reveal that nascent features of tonal music (e.g., consonance/dissonance, pitch salience, harmonic sonority are evident at early, subcortical levels of the auditory pathway. The salience and harmonicity of brainstem activity is strongly correlated with listeners’ perceptual preferences and perceived consonance for the tonal relationships of music. Moreover, the hierarchical ordering of pitch intervals/chords described by the Western music practice and their perceptual consonance is well-predicted by the salience with which pitch combinations are encoded in subcortical auditory structures. While the neural correlates of consonance can be tuned and exaggerated with musical training, they persist even in the absence of musicianship or long-term enculturation. As such, it is posited that the structural foundations of musical pitch might result from innate processing performed by the central auditory system. A neurobiological predisposition for consonant, pleasant sounding pitch relationships may be one reason why these pitch combinations have been favored by composers and listeners for centuries. It is suggested that important perceptual dimensions of music emerge well before the auditory signal reaches cerebral cortex and prior to attentional engagement. While cortical mechanisms are no doubt critical to the perception, production, and enjoyment of music, the contribution of subcortical structures implicates a more integrated, hierarchically organized network underlying music processing within the brain.

  6. The role of the auditory brainstem in processing musically relevant pitch.

    Science.gov (United States)

    Bidelman, Gavin M

    2013-01-01

    Neuroimaging work has shed light on the cerebral architecture involved in processing the melodic and harmonic aspects of music. Here, recent evidence is reviewed illustrating that subcortical auditory structures contribute to the early formation and processing of musically relevant pitch. Electrophysiological recordings from the human brainstem and population responses from the auditory nerve reveal that nascent features of tonal music (e.g., consonance/dissonance, pitch salience, harmonic sonority) are evident at early, subcortical levels of the auditory pathway. The salience and harmonicity of brainstem activity is strongly correlated with listeners' perceptual preferences and perceived consonance for the tonal relationships of music. Moreover, the hierarchical ordering of pitch intervals/chords described by the Western music practice and their perceptual consonance is well-predicted by the salience with which pitch combinations are encoded in subcortical auditory structures. While the neural correlates of consonance can be tuned and exaggerated with musical training, they persist even in the absence of musicianship or long-term enculturation. As such, it is posited that the structural foundations of musical pitch might result from innate processing performed by the central auditory system. A neurobiological predisposition for consonant, pleasant sounding pitch relationships may be one reason why these pitch combinations have been favored by composers and listeners for centuries. It is suggested that important perceptual dimensions of music emerge well before the auditory signal reaches cerebral cortex and prior to attentional engagement. While cortical mechanisms are no doubt critical to the perception, production, and enjoyment of music, the contribution of subcortical structures implicates a more integrated, hierarchically organized network underlying music processing within the brain.

  7. Hierarchical β-Mo2 C Nanotubes Organized by Ultrathin Nanosheets as a Highly Efficient Electrocatalyst for Hydrogen Production.

    Science.gov (United States)

    Ma, Fei-Xiang; Wu, Hao Bin; Xia, Bao Yu; Xu, Cheng-Yan; Lou, Xiong Wen David

    2015-12-14

    Production of hydrogen by electrochemical water splitting has been hindered by the high cost of precious metal catalysts, such as Pt, for the hydrogen evolution reaction (HER). In this work, novel hierarchical β-Mo2 C nanotubes constructed from porous nanosheets have been fabricated and investigated as a high-performance and low-cost electrocatalyst for HER. An unusual template-engaged strategy has been utilized to controllably synthesize Mo-polydopamine nanotubes, which are further converted into hierarchical β-Mo2 C nanotubes by direct carburization at high temperature. Benefitting from several structural advantages including ultrafine primary nanocrystallites, large exposed surface, fast charge transfer, and unique tubular structure, the as-prepared hierarchical β-Mo2 C nanotubes exhibit excellent electrocatalytic performance for HER with small overpotential in both acidic and basic conditions, as well as remarkable stability.

  8. Growth mechanism and photocatalytic activity of self-organized N-doped (BiO)₂CO₃ hierarchical nanosheet microspheres from bismuth citrate and urea.

    Science.gov (United States)

    Dong, Fan; Xiong, Ting; Wang, Rui; Sun, Yanjuan; Jiang, Yanke

    2014-05-14

    Synthesis of nano-/microstructured functional materials with 3D hierarchical microspheres structure has provided new opportunities for optimizing their physical and chemical properties. This work revealed a new growth mechanism of self-organized N-doped (BiO)2CO3 hierarchical microspheres which were fabricated by hydrothermal treatment of bismuth citrate and urea without an additive. Based on time-dependent observation, several evolution processes were believed to account for the formation of the self-organized N-doped (BiO)2CO3 hierarchical microspheres. Initially, crystallized (BiO)4CO3(OH)2 particles were formed during the nucleation and crystallization processes. Subsequently, the intermediate (BiO)4CO3(OH)2 reacted with CO3(2-) to generate (BiO)2CO3 growth nuclei on the surface of the CO2 bubbles which can act as heterogeneous nucleation centers. Next, the (BiO)2CO3 growth nuclei aggregated together after the consumption of CO2 bubbles with the increased concentration of OH(-) and further grew to be nanosheets. The microspheres constructed by small nanosheets further grew with the consumption of small particles. Finally, all (BiO)4CO3(OH)2 transformed to the (BiO)2CO3 phase, accompanied by the doping of N element into the lattice of (BiO)2CO3, and thereby, the well-defined N-doped (BiO)2CO3 hierarchical microspheres were shaped. Depending on the distance between neighboring CO2 bubbles, the resulting microspheres can be linked or dispersed. Besides, the gradual release of CO2 bubbles and CO3(2-) played a crucial role in controlling the nucleation and growth process, resulting in different sizes of microspheres. The fabricated N-doped (BiO)2CO3 hierarchical microspheres displayed admirably efficient and durable photocatalytic activity under both UV and visible light towards removal of NO, which is mainly attributed to the introduction of N element and the special hierarchical structure. This work provides new insights into the controlled synthesis of

  9. Detecting Hierarchical Structure in Networks

    DEFF Research Database (Denmark)

    Herlau, Tue; Mørup, Morten; Schmidt, Mikkel Nørgaard;

    2012-01-01

    a generative Bayesian model that is able to infer whether hierarchies are present or not from a hypothesis space encompassing all types of hierarchical tree structures. For efficient inference we propose a collapsed Gibbs sampling procedure that jointly infers a partition and its hierarchical structure......Many real-world networks exhibit hierarchical organization. Previous models of hierarchies within relational data has focused on binary trees; however, for many networks it is unknown whether there is hierarchical structure, and if there is, a binary tree might not account well for it. We propose....... On synthetic and real data we demonstrate that our model can detect hierarchical structure leading to better link-prediction than competing models. Our model can be used to detect if a network exhibits hierarchical structure, thereby leading to a better comprehension and statistical account the network....

  10. Hierarchical hollow Fe2O3@MIL-101(Fe)/C derived from metal-organic frameworks for superior sodium storage

    Science.gov (United States)

    Li, Chengping; Hu, Qian; Li, Yan; Zhou, Hang; Lv, Zhaolin; Yang, Xiangjun; Liu, Lixiang; Guo, Hong

    2016-05-01

    A facile generic template-free strategy is employed to prepare hierarchical hollow hybrid Fe2O3@MIL-101(Fe)/C materials derived from metal-organic frameworks as anode materials for Na-ion batteries. The intrinsic hollow nanostructure can shorten the lengths for both electronic and ionic transport, enlarge the surface areas of electrodes, and improve accommodation of the volume change during Na+ insertion/extraction cycling. Therefore, The stable reversible capacity of Fe2O3@MIL-101(Fe)/C electrode is 710 mAhg‑1, and can be retained at 662 mAhg‑1 after 200 cycles with the retention of 93.2%. Especially, its overall rate performance data confirm again the importance of the hierarchical hollow structures and multi-elements characteristics toward high capacities in both low and high current rates. This general strategy may shed light on a new avenue for fast synthesis of hierarchic hollow functional materials for energy storage, catalyst, sensor and other new applications.

  11. In-situ observation for growth of hierarchical metal-organic frameworks and their self-sequestering mechanism for gas storage

    Science.gov (United States)

    Hyo Park, Jung; Min Choi, Kyung; Joon Jeon, Hyung; Jung Choi, Yoon; Ku Kang, Jeung

    2015-07-01

    Although structures with the single functional constructions and micropores were demonstrated to capture many different molecules such as carbon dioxide, methane, and hydrogen with high capacities at low temperatures, their feeble interactions still limit practical applications at room temperature. Herein, we report in-situ growth observation of hierarchical pores in pomegranate metal-organic frameworks (pmg-MOFs) and their self-sequestering storage mechanism, not observed for pristine MOFs. Direct observation of hierarchical pores inside the pmg-MOF was evident by in-situ growth X-ray measurements while self-sequestering storage mechanism was revealed by in-situ gas sorption X-ray analysis and molecular dynamics simulations. The results show that meso/macropores are created at the early stage of crystal growth and then enclosed by micropore crystalline shells, where hierarchical pores are networking under self-sequestering mechanism to give enhanced gas storage. This pmg-MOF gives higher CO2 (39%) and CH4 (14%) storage capacity than pristine MOF at room temperature, in addition to fast kinetics with robust capacity retention during gas sorption cycles, thus giving the clue to control dynamic behaviors of gas adsorption.

  12. Hierarchical photocatalysts.

    Science.gov (United States)

    Li, Xin; Yu, Jiaguo; Jaroniec, Mietek

    2016-05-01

    As a green and sustainable technology, semiconductor-based heterogeneous photocatalysis has received much attention in the last few decades because it has potential to solve both energy and environmental problems. To achieve efficient photocatalysts, various hierarchical semiconductors have been designed and fabricated at the micro/nanometer scale in recent years. This review presents a critical appraisal of fabrication methods, growth mechanisms and applications of advanced hierarchical photocatalysts. Especially, the different synthesis strategies such as two-step templating, in situ template-sacrificial dissolution, self-templating method, in situ template-free assembly, chemically induced self-transformation and post-synthesis treatment are highlighted. Finally, some important applications including photocatalytic degradation of pollutants, photocatalytic H2 production and photocatalytic CO2 reduction are reviewed. A thorough assessment of the progress made in photocatalysis may open new opportunities in designing highly effective hierarchical photocatalysts for advanced applications ranging from thermal catalysis, separation and purification processes to solar cells.

  13. Intracranial Electrophysiology of Auditory Selective Attention Associated with Speech Classification Tasks

    Science.gov (United States)

    Nourski, Kirill V.; Steinschneider, Mitchell; Rhone, Ariane E.; Howard III, Matthew A.

    2017-01-01

    Auditory selective attention paradigms are powerful tools for elucidating the various stages of speech processing. This study examined electrocorticographic activation during target detection tasks within and beyond auditory cortex. Subjects were nine neurosurgical patients undergoing chronic invasive monitoring for treatment of medically refractory epilepsy. Four subjects had left hemisphere electrode coverage, four had right coverage and one had bilateral coverage. Stimuli were 300 ms complex tones or monosyllabic words, each spoken by a different male or female talker. Subjects were instructed to press a button whenever they heard a target corresponding to a specific stimulus category (e.g., tones, animals, numbers). High gamma (70–150 Hz) activity was simultaneously recorded from Heschl’s gyrus (HG), superior, middle temporal and supramarginal gyri (STG, MTG, SMG), as well as prefrontal cortex (PFC). Data analysis focused on: (1) task effects (non-target words in tone detection vs. semantic categorization task); and (2) target effects (words as target vs. non-target during semantic classification). Responses within posteromedial HG (auditory core cortex) were minimally modulated by task and target. Non-core auditory cortex (anterolateral HG and lateral STG) exhibited sensitivity to task, with a smaller proportion of sites showing target effects. Auditory-related areas (MTG and SMG) and PFC showed both target and, to a lesser extent, task effects, that occurred later than those in the auditory cortex. Significant task and target effects were more prominent in the left hemisphere than in the right. Findings demonstrate a hierarchical organization of speech processing during auditory selective attention. PMID:28119593

  14. Seeing the song: left auditory structures may track auditory-visual dynamic alignment.

    Directory of Open Access Journals (Sweden)

    Julia A Mossbridge

    Full Text Available Auditory and visual signals generated by a single source tend to be temporally correlated, such as the synchronous sounds of footsteps and the limb movements of a walker. Continuous tracking and comparison of the dynamics of auditory-visual streams is thus useful for the perceptual binding of information arising from a common source. Although language-related mechanisms have been implicated in the tracking of speech-related auditory-visual signals (e.g., speech sounds and lip movements, it is not well known what sensory mechanisms generally track ongoing auditory-visual synchrony for non-speech signals in a complex auditory-visual environment. To begin to address this question, we used music and visual displays that varied in the dynamics of multiple features (e.g., auditory loudness and pitch; visual luminance, color, size, motion, and organization across multiple time scales. Auditory activity (monitored using auditory steady-state responses, ASSR was selectively reduced in the left hemisphere when the music and dynamic visual displays were temporally misaligned. Importantly, ASSR was not affected when attentional engagement with the music was reduced, or when visual displays presented dynamics clearly dissimilar to the music. These results appear to suggest that left-lateralized auditory mechanisms are sensitive to auditory-visual temporal alignment, but perhaps only when the dynamics of auditory and visual streams are similar. These mechanisms may contribute to correct auditory-visual binding in a busy sensory environment.

  15. Supercapacitance of nitrogen-sulfur-oxygen co-doped 3D hierarchical porous carbon in aqueous and organic electrolyte

    Science.gov (United States)

    Yang, Wang; Yang, Wu; Song, Ailing; Gao, Lijun; Su, Li; Shao, Guangjie

    2017-08-01

    This work report the synthesis of porous carbon with hierarchical pore structure and uniform nitrogen-sulfur-oxygen doping. The favorable pore structure (micro-, meso-, and macro-pores) is beneficial to ion adsorption and transportation, and the doping heteroatoms can introduce electrochemical active sites which contribute to additional pseudocapacitance. Therefore, the carbon material shows good electrochemical performance when employed as supercapacitor electrode. High specific capacitance (367 F g-1 at 0.3 A g-1), good rate performance and stable cycling characteristics are obtained in 6 M KOH. In addition, when tested in 1 M H2SO4, a higher specific capacitance (382 F g-1 at 0.3 A g-1) is delivered. Furthermore, the assembled symmetric cell yields a maximum specific energy of 35.3 W h kg-1 in 1 M TEABF4/AN, significantly improving the specific energy of carbon-based supercapacitors.

  16. 3D hierarchical rutile TiO2 and metal-free organic sensitizer producing dye-sensitized solar cells 8.6% conversion efficiency.

    Science.gov (United States)

    Lin, Jianjian; Heo, Yoon-Uk; Nattestad, Andrew; Sun, Ziqi; Wang, Lianzhou; Kim, Jung Ho; Dou, Shi Xue

    2014-08-29

    Three-dimensional (3D) hierarchical nanoscale architectures comprised of building blocks, with specifically engineered morphologies, are expected to play important roles in the fabrication of 'next generation' microelectronic and optoelectronic devices due to their high surface-to-volume ratio as well as opto-electronic properties. Herein, a series of well-defined 3D hierarchical rutile TiO2 architectures (HRT) were successfully prepared using a facile hydrothermal method without any surfactant or template, simply by changing the concentration of hydrochloric acid used in the synthesis. The production of these materials provides, to the best of our knowledge, the first identified example of a ledgewise growth mechanism in a rutile TiO2 structure. Also for the first time, a Dye-sensitized Solar Cell (DSC) combining a HRT is reported in conjunction with a high-extinction-coefficient metal-free organic sensitizer (D149), achieving a conversion efficiency of 5.5%, which is superior to ones employing P25 (4.5%), comparable to state-of-the-art commercial transparent titania anatase paste (5.8%). Further to this, an overall conversion efficiency 8.6% was achieved when HRT was used as the light scattering layer, a considerable improvement over the commercial transparent/reflector titania anatase paste (7.6%), a significantly smaller gap in performance than has been seen previously.

  17. [Auditory fatigue].

    Science.gov (United States)

    Sanjuán Juaristi, Julio; Sanjuán Martínez-Conde, Mar

    2015-01-01

    Given the relevance of possible hearing losses due to sound overloads and the short list of references of objective procedures for their study, we provide a technique that gives precise data about the audiometric profile and recruitment factor. Our objectives were to determine peripheral fatigue, through the cochlear microphonic response to sound pressure overload stimuli, as well as to measure recovery time, establishing parameters for differentiation with regard to current psychoacoustic and clinical studies. We used specific instruments for the study of cochlear microphonic response, plus a function generator that provided us with stimuli of different intensities and harmonic components. In Wistar rats, we first measured the normal microphonic response and then the effect of auditory fatigue on it. Using a 60dB pure tone acoustic stimulation, we obtained a microphonic response at 20dB. We then caused fatigue with 100dB of the same frequency, reaching a loss of approximately 11dB after 15minutes; after that, the deterioration slowed and did not exceed 15dB. By means of complex random tone maskers or white noise, no fatigue was caused to the sensory receptors, not even at levels of 100dB and over an hour of overstimulation. No fatigue was observed in terms of sensory receptors. Deterioration of peripheral perception through intense overstimulation may be due to biochemical changes of desensitisation due to exhaustion. Auditory fatigue in subjective clinical trials presumably affects supracochlear sections. The auditory fatigue tests found are not in line with those obtained subjectively in clinical and psychoacoustic trials. Copyright © 2013 Elsevier España, S.L.U. y Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

  18. Auditory Hallucination

    Directory of Open Access Journals (Sweden)

    MohammadReza Rajabi

    2003-09-01

    Full Text Available Auditory Hallucination or Paracusia is a form of hallucination that involves perceiving sounds without auditory stimulus. A common is hearing one or more talking voices which is associated with psychotic disorders such as schizophrenia or mania. Hallucination, itself, is the most common feature of perceiving the wrong stimulus or to the better word perception of the absence stimulus. Here we will discuss four definitions of hallucinations:1.Perceiving of a stimulus without the presence of any subject; 2. hallucination proper which are the wrong perceptions that are not the falsification of real perception, Although manifest as a new subject and happen along with and synchronously with a real perception;3. hallucination is an out-of-body perception which has no accordance with a real subjectIn a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and located in external objective space. We are going to discuss it in details here.

  19. Hierarchical (Ni,Co)Se 2 /Carbon Hollow Rhombic Dodecahedra Derived from Metal-Organic Frameworks for Efficient Water-Splitting Electrocatalysis

    KAUST Repository

    Ming, Fangwang

    2017-08-12

    In this work, we demonstrate that the electrocatalytic activity of transition metal chalcogenides can be greatly enhanced by simultaneously engineering the active sites, surface area, and conductivity. Using metal-organic frameworks-derived (Ni,Co)Se2/C hollow rhombic dodecahedra (HRD) as a demonstration, we show that the incorporation of Ni into CoSe2 could generates additional active sites, the hierarchical hollow structure promotes the electrolyte diffusion, the in-situ hybridization with C improves the conductivity. As a result, the (Ni,Co)Se2/C HRD exhibit superior performance toward the overall water-splitting electrocatalysis in 1M KOH with a cell voltage as low as 1.58V at the current density of 10mAcm−2, making the (Ni,Co)Se2/C HRD as a promising alternative to noble metal catalysts for water splitting.

  20. The auditory organ: active amplifier and highly sensitive measuring system; Das Hoerorgan: Aktiver Schallverstaerker und hochempfindliches Messsystem

    Energy Technology Data Exchange (ETDEWEB)

    Kafka-Luetzow, A. [Univ. Wien (Austria). Inst. fuer Allgemeine und Vergleichende Physiologie

    1997-12-01

    The present paper provides a brief review on topical issues of auditory physiology. Recent data on transduction mechanism and adaptation in hair cells as well as on the possible role of outer hair cells in amplifying basilar membrane motion are presented. Strategies of present physiological research in dealing with sensorineural deafness are discussed. (orig.) [Deutsch] Neuere Erkenntnisse der Hoerphysiologie haben einige der Mechanismen aufgezeigt, welche fuer die hohe Empfindlichkeit, die gute Frequenzdiskrimination und das bei Lautstaerkenerhoehung nicht lineare Verhalten dieses Sinnessystems verantwortlich sein duerften. Demnach haben die 2 Typen akustischer Sinneszellen voellig unterschiedliche Funktionen. Nur ein Typ, die Inneren Haarzellen, duerften Sensoren im engeren Sinn sein, indem sie die wesentliche akustische Information an das Zentralnervensystem liefern. Der zweite Typ, die Aeusseren Haarzellen scheinen vornehmlich als Eingangsverstaerker zu fungieren. Sie setzen die bei Schalleinwirkung auf das Ohr an ihrer Membran auftretende Potentialaenderung in rasche Laengskontraktionen um. Damit verstaerken sie die durch die Schalleinwirkung ausgeloesten Basilarmembranschwingungen. Ausserdem duerften die von den Aeusseren Haarzellen aktiv erzeugten Schwingungen die Quelle der im aeusseren Gehoergang messbaren `otoakustischen Emissionen` sein. Die gegenstaendliche Uebersicht fasst den aktuellen Wissensstand ueber den Transduktionsmechanismus und die Elektromotilitaet der Haarzellen zusammen. Darueber hinaus wird die moegliche auditive Funktion von Haarzellen im Gleichgewichtssystem sowie Befunde aus der in den letzten Jahren entbrannten Diskussion um eine allfaellige Regeneration von Haarzellen aus dem vestibulocochleaeren System von adulten Saeugern diskutiert. Im Zusammenhang mit der Druckausbreitung im Innenohr werden einige morphologische Besonderheiten insbesonders der cochleaeren Fluessigkeitsraeume und ihrer Verbindungen sowie deren funktionelle

  1. The Cancer Stem Cell Fraction in Hierarchically Organized Tumors Can Be Estimated Using Mathematical Modeling and Patient-Specific Treatment Trajectories.

    Science.gov (United States)

    Werner, Benjamin; Scott, Jacob G; Sottoriva, Andrea; Anderson, Alexander R A; Traulsen, Arne; Altrock, Philipp M

    2016-04-01

    Many tumors are hierarchically organized and driven by a subpopulation of tumor-initiating cells (TIC), or cancer stem cells. TICs are uniquely capable of recapitulating the tumor and are thought to be highly resistant to radio- and chemotherapy. Macroscopic patterns of tumor expansion before treatment and tumor regression during treatment are tied to the dynamics of TICs. Until now, the quantitative information about the fraction of TICs from macroscopic tumor burden trajectories could not be inferred. In this study, we generated a quantitative method based on a mathematical model that describes hierarchically organized tumor dynamics and patient-derived tumor burden information. The method identifies two characteristic equilibrium TIC regimes during expansion and regression. We show that tumor expansion and regression curves can be leveraged to infer estimates of the TIC fraction in individual patients at detection and after continued therapy. Furthermore, our method is parameter-free; it solely requires the knowledge of a patient's tumor burden over multiple time points to reveal microscopic properties of the malignancy. We demonstrate proof of concept in the case of chronic myeloid leukemia (CML), wherein our model recapitulated the clinical history of the disease in two independent patient cohorts. On the basis of patient-specific treatment responses in CML, we predict that after one year of targeted treatment, the fraction of TICs increases 100-fold and continues to increase up to 1,000-fold after 5 years of treatment. Our novel framework may significantly influence the implementation of personalized treatment strategies and has the potential for rapid translation into the clinic. Cancer Res; 76(7); 1705-13. ©2016 AACR.

  2. A novel family of Toxoplasma IMC proteins displays a hierarchical organization and functions in coordinating parasite division.

    Science.gov (United States)

    Beck, Josh R; Rodriguez-Fernandez, Imilce A; de Leon, Jessica Cruz; Huynh, My-Hang; Carruthers, Vern B; Morrissette, Naomi S; Bradley, Peter J

    2010-09-09

    Apicomplexans employ a peripheral membrane system called the inner membrane complex (IMC) for critical processes such as host cell invasion and daughter cell formation. We have identified a family of proteins that define novel sub-compartments of the Toxoplasma gondii IMC. These IMC Sub-compartment Proteins, ISP1, 2 and 3, are conserved throughout the Apicomplexa, but do not appear to be present outside the phylum. ISP1 localizes to the apical cap portion of the IMC, while ISP2 localizes to a central IMC region and ISP3 localizes to a central plus basal region of the complex. Targeting of all three ISPs is dependent upon N-terminal residues predicted for coordinated myristoylation and palmitoylation. Surprisingly, we show that disruption of ISP1 results in a dramatic relocalization of ISP2 and ISP3 to the apical cap. Although the N-terminal region of ISP1 is necessary and sufficient for apical cap targeting, exclusion of other family members requires the remaining C-terminal region of the protein. This gate-keeping function of ISP1 reveals an unprecedented mechanism of interactive and hierarchical targeting of proteins to establish these unique sub-compartments in the Toxoplasma IMC. Finally, we show that loss of ISP2 results in severe defects in daughter cell formation during endodyogeny, indicating a role for the ISP proteins in coordinating this unique process of Toxoplasma replication.

  3. Hierarchical model of fibrillar collagen organization for interpreting the second-order susceptibility tensors in biological tissue.

    Science.gov (United States)

    Tuer, Adam E; Akens, Margarete K; Krouglov, Serguei; Sandkuijl, Daaf; Wilson, Brian C; Whyne, Cari M; Barzda, Virginijus

    2012-11-21

    The second-order nonlinear polarization properties of fibrillar collagen in various rat tissues (vertebrae, tibia, tail tendon, dermis, and cornea) are investigated with polarization-dependent second-harmonic generation (P-SHG) microscopy. Three parameters are extracted: the second-order susceptibility ratio, R = [Formula: see text] ; a measure of the fibril distribution asymmetry, |A|; and the weighted-average fibril orientation, . A hierarchical organizational model of fibrillar collagen is developed to interpret the second-harmonic generation polarization properties. Highlights of the model include: collagen type (e.g., type-I, type-II), fibril internal structure (e.g., straight, constant-tilt), and fibril architecture (e.g., parallel fibers, intertwined, lamellae). Quantifiable differences in internal structure and architecture of the fibrils are observed. Occurrence histograms of R and |A| distinguished parallel from nonparallel fibril distributions. Parallel distributions possessed low parameter values and variability, whereas nonparallel distributions displayed an increase in values and variability. From the P-SHG parameters of vertebrae tissue, a three-dimensional reconstruction of lamellae of intervertebral disk is presented.

  4. A novel family of Toxoplasma IMC proteins displays a hierarchical organization and functions in coordinating parasite division.

    Directory of Open Access Journals (Sweden)

    Josh R Beck

    Full Text Available Apicomplexans employ a peripheral membrane system called the inner membrane complex (IMC for critical processes such as host cell invasion and daughter cell formation. We have identified a family of proteins that define novel sub-compartments of the Toxoplasma gondii IMC. These IMC Sub-compartment Proteins, ISP1, 2 and 3, are conserved throughout the Apicomplexa, but do not appear to be present outside the phylum. ISP1 localizes to the apical cap portion of the IMC, while ISP2 localizes to a central IMC region and ISP3 localizes to a central plus basal region of the complex. Targeting of all three ISPs is dependent upon N-terminal residues predicted for coordinated myristoylation and palmitoylation. Surprisingly, we show that disruption of ISP1 results in a dramatic relocalization of ISP2 and ISP3 to the apical cap. Although the N-terminal region of ISP1 is necessary and sufficient for apical cap targeting, exclusion of other family members requires the remaining C-terminal region of the protein. This gate-keeping function of ISP1 reveals an unprecedented mechanism of interactive and hierarchical targeting of proteins to establish these unique sub-compartments in the Toxoplasma IMC. Finally, we show that loss of ISP2 results in severe defects in daughter cell formation during endodyogeny, indicating a role for the ISP proteins in coordinating this unique process of Toxoplasma replication.

  5. Converting 2D inorganic-organic ZnSe-DETA hybrid nanosheets into 3D hierarchical nanosheet-based ZnSe microspheres with enhanced visible-light-driven photocatalytic performances

    Science.gov (United States)

    Wu, Xuan; Xu, Rui; Zhu, Rongjiao; Wu, Rui; Zhang, Bin

    2015-05-01

    Engineering two-dimensional (2D) nanosheets into three-dimensional (3D) hierarchical structures is one of the great challenges in nanochemistry and materials science. We report a facile and simple chemical conversion route to fabricate 3D hierarchical nanosheet-based ZnSe microspheres by using 2D inorganic-organic hybrid ZnSe-DETA (DETA = diethylenetriamine) nanosheets as the starting precursors. The conversion mechanism involves the controlled depletion of the organic-component (DETA) from the hybrid precursors and the subsequent self-assembly of the remnant inorganic-component (ZnSe). The transformation reaction of ZnSe-DETA nanosheets is mainly influenced by the concentration of DETA in the reaction solution. We demonstrated that this organic-component depletion method could be extended to the synthesis of other hierarchical structures of metal sulfides. In addition, the obtained hierarchical nanosheet-based ZnSe microspheres exhibited outstanding performance in visible light photocatalytic degradation of methyl orange and were highly active for photocatalytic H2 production.Engineering two-dimensional (2D) nanosheets into three-dimensional (3D) hierarchical structures is one of the great challenges in nanochemistry and materials science. We report a facile and simple chemical conversion route to fabricate 3D hierarchical nanosheet-based ZnSe microspheres by using 2D inorganic-organic hybrid ZnSe-DETA (DETA = diethylenetriamine) nanosheets as the starting precursors. The conversion mechanism involves the controlled depletion of the organic-component (DETA) from the hybrid precursors and the subsequent self-assembly of the remnant inorganic-component (ZnSe). The transformation reaction of ZnSe-DETA nanosheets is mainly influenced by the concentration of DETA in the reaction solution. We demonstrated that this organic-component depletion method could be extended to the synthesis of other hierarchical structures of metal sulfides. In addition, the obtained

  6. Otalgia and eschar in the external auditory canal in scrub typhus complicated by acute respiratory distress syndrome and multiple organ failure

    Directory of Open Access Journals (Sweden)

    Hu Sung-Yuan

    2011-03-01

    Full Text Available Abstract Background Scrub typhus, a mite-transmitted zoonosis caused by Orientia tsutsugamushi, is an endemic disease in Taiwan and may be potentially fatal if diagnosis is delayed. Case presentations We encountered a 23-year-old previously healthy Taiwanese male soldier presenting with the right ear pain after training in the jungle and an eleven-day history of intermittent high fever up to 39°C. Amoxicillin/clavulanate was prescribed for otitis media at a local clinic. Skin rash over whole body and abdominal cramping pain with watery diarrhea appeared on the sixth day of fever. He was referred due to progressive dyspnea and cough for 4 days prior to admission in our institution. On physical examination, there were cardiopulmonary distress, icteric sclera, an eschar in the right external auditory canal and bilateral basal rales. Laboratory evaluation revealed thrombocytopenia, elevation of liver function and acute renal failure. Chest x-ray revealed bilateral diffuse infiltration. Doxycycline was prescribed for scrub typhus with acute respiratory distress syndrome and multiple organ failure. Fever subsided dramatically the next day and he was discharged on day 7 with oral tetracycline for 7 days. Conclusion Scrub typhus should be considered in acutely febrile patients with multiple organ involvement, particularly if there is an eschar or a history of environmental exposure in endemic areas. Rapid and accurate diagnosis, timely administration of antibiotics and intensive supportive care are necessary to decrease mortality of serious complications of scrub typhus.

  7. Functional annotation of hierarchical modularity.

    Directory of Open Access Journals (Sweden)

    Kanchana Padmanabhan

    Full Text Available In biological networks of molecular interactions in a cell, network motifs that are biologically relevant are also functionally coherent, or form functional modules. These functionally coherent modules combine in a hierarchical manner into larger, less cohesive subsystems, thus revealing one of the essential design principles of system-level cellular organization and function-hierarchical modularity. Arguably, hierarchical modularity has not been explicitly taken into consideration by most, if not all, functional annotation systems. As a result, the existing methods would often fail to assign a statistically significant functional coherence score to biologically relevant molecular machines. We developed a methodology for hierarchical functional annotation. Given the hierarchical taxonomy of functional concepts (e.g., Gene Ontology and the association of individual genes or proteins with these concepts (e.g., GO terms, our method will assign a Hierarchical Modularity Score (HMS to each node in the hierarchy of functional modules; the HMS score and its p-value measure functional coherence of each module in the hierarchy. While existing methods annotate each module with a set of "enriched" functional terms in a bag of genes, our complementary method provides the hierarchical functional annotation of the modules and their hierarchically organized components. A hierarchical organization of functional modules often comes as a bi-product of cluster analysis of gene expression data or protein interaction data. Otherwise, our method will automatically build such a hierarchy by directly incorporating the functional taxonomy information into the hierarchy search process and by allowing multi-functional genes to be part of more than one component in the hierarchy. In addition, its underlying HMS scoring metric ensures that functional specificity of the terms across different levels of the hierarchical taxonomy is properly treated. We have evaluated our

  8. Hierarchical Classes Analysis (HICLAS: A novel data reduction method to examine associations between biallelic SNPs and perceptual organization phenotypes in schizophrenia

    Directory of Open Access Journals (Sweden)

    Jamie Joseph

    2015-06-01

    Full Text Available The power of SNP association studies to detect valid relationships with clinical phenotypes in schizophrenia is largely limited by the number of SNPs selected and non-specificity of phenotypes. To address this, we first assessed performance on two visual perceptual organization tasks designed to avoid many generalized deficit confounds, Kanizsa shape perception and contour integration, in a schizophrenia patient sample. Then, to reduce the total number of candidate SNPs analyzed in association with perceptual organization phenotypes, we employed a two-stage strategy: first a priori SNPs from three candidate genes were selected (GAD1, NRG1 and DTNBP1; then a Hierarchical Classes Analysis (HICLAS was performed to reduce the total number of SNPs, based on statistically related SNP clusters. HICLAS reduced the total number of candidate SNPs for subsequent phenotype association analyses from 6 to 3. MANCOVAs indicated that rs10503929 and rs1978340 were associated with the Kanizsa shape perception filling in metric but not the global shape detection metric. rs10503929 was also associated with altered contour integration performance. SNPs not selected by the HICLAS model were unrelated to perceptual phenotype indices. While the contribution of candidate SNPs to perceptual impairments requires further clarification, this study reports the first application of HICLAS as a hypothesis-independent mathematical method for SNP data reduction. HICLAS may be useful for future larger scale genotype-phenotype association studies.

  9. Translation and adaptation of functional auditory performance indicators (FAPI

    Directory of Open Access Journals (Sweden)

    Karina Ferreira

    2011-12-01

    Full Text Available Work with deaf children has gained new attention since the expectation and goal of therapy has expanded to language development and subsequent language learning. Many clinical tests were developed for evaluation of speech sound perception in young children in response to the need for accurate assessment of hearing skills that developed from the use of individual hearing aids or cochlear implants. These tests also allow the evaluation of the rehabilitation program. However, few of these tests are available in Portuguese. Evaluation with the Functional Auditory Performance Indicators (FAPI generates a child's functional auditory skills profile, which lists auditory skills in an integrated and hierarchical order. It has seven hierarchical categories, including sound awareness, meaningful sound, auditory feedback, sound source localizing, auditory discrimination, short-term auditory memory, and linguistic auditory processing. FAPI evaluation allows the therapist to map the child's hearing profile performance, determine the target for increasing the hearing abilities, and develop an effective therapeutic plan. Objective: Since the FAPI is an American test, the inventory was adapted for application in the Brazilian population. Material and Methods: The translation was done following the steps of translation and back translation, and reproducibility was evaluated. Four translated versions (two originals and two back-translated were compared, and revisions were done to ensure language adaptation and grammatical and idiomatic equivalence. Results: The inventory was duly translated and adapted. Conclusion: Further studies about the application of the translated FAPI are necessary to make the test practicable in Brazilian clinical use.

  10. The auditory-vibratory system of the bushcricket Polysarcus denticauda (Phaneropterinae, Tettigoniidae). I. Morphology of the complex tibial organs.

    Science.gov (United States)

    Sickmann, T; Kalmring, K; Müller, A

    1997-02-01

    The structure of the complex tibial organs in the fore-, mid- and hindlegs of the bushcricket Polysarcus denticauda (Tettigoniidae, Phaneropterinae) is described comparatively. As is common for bushcrickets, in each leg the tibial organs consist of the subgenual and intermediate organs and the crista acustica. Only in the forelegs are sound-transmitting structures present. They consist of the spiracle, acoustic trachea, and two tympana; the latter are not protected by tympanal covers. The tympana in P. denticauda are extremely thick, not only bordering the two tracheal branches to the outside but also forming the outer wall of the hemolymph channel. The morphology of the tracheae in the mid- and hindlegs is significantly different, causing structural differences, especially in dimensions of the hemolymph channel. The number of scolopidia of the crista acustica of the foreleg is extremely high for a bushcricket. Approximately 50 receptor cells were found, about half of them being located in the distal quarter of the long axis of this organ. Some of the receptors are positioned in parallel on the dorsal wall of the anterior tracheal branch. The number, morphology and dimensions of the scolopidia within the crista acustica of the mid- and hindlegs differ significantly from those of the forelegs, decreasing in both legs to eight and seven receptor cells, respectively. Although the dimensions of the subgenual and intermediate organs are considerably larger in the mid- and hindlegs, the number of receptor cells is approximately the same in the different legs, being somewhat higher in both receptor organs than in those of many other bushcricket species studied previously.

  11. Converting 2D inorganic-organic ZnSe-DETA hybrid nanosheets into 3D hierarchical nanosheet-based ZnSe microspheres with enhanced visible-light-driven photocatalytic performances.

    Science.gov (United States)

    Wu, Xuan; Xu, Rui; Zhu, Rongjiao; Wu, Rui; Zhang, Bin

    2015-06-07

    Engineering two-dimensional (2D) nanosheets into three-dimensional (3D) hierarchical structures is one of the great challenges in nanochemistry and materials science. We report a facile and simple chemical conversion route to fabricate 3D hierarchical nanosheet-based ZnSe microspheres by using 2D inorganic-organic hybrid ZnSe-DETA (DETA = diethylenetriamine) nanosheets as the starting precursors. The conversion mechanism involves the controlled depletion of the organic-component (DETA) from the hybrid precursors and the subsequent self-assembly of the remnant inorganic-component (ZnSe). The transformation reaction of ZnSe-DETA nanosheets is mainly influenced by the concentration of DETA in the reaction solution. We demonstrated that this organic-component depletion method could be extended to the synthesis of other hierarchical structures of metal sulfides. In addition, the obtained hierarchical nanosheet-based ZnSe microspheres exhibited outstanding performance in visible light photocatalytic degradation of methyl orange and were highly active for photocatalytic H2 production.

  12. HDS: Hierarchical Data System

    Science.gov (United States)

    Pearce, Dave; Walter, Anton; Lupton, W. F.; Warren-Smith, Rodney F.; Lawden, Mike; McIlwrath, Brian; Peden, J. C. M.; Jenness, Tim; Draper, Peter W.

    2015-02-01

    The Hierarchical Data System (HDS) is a file-based hierarchical data system designed for the storage of a wide variety of information. It is particularly suited to the storage of large multi-dimensional arrays (with their ancillary data) where efficient access is needed. It is a key component of the Starlink software collection (ascl:1110.012) and is used by the Starlink N-Dimensional Data Format (NDF) library (ascl:1411.023). HDS organizes data into hierarchies, broadly similar to the directory structure of a hierarchical filing system, but contained within a single HDS container file. The structures stored in these files are self-describing and flexible; HDS supports modification and extension of structures previously created, as well as functions such as deletion, copying, and renaming. All information stored in HDS files is portable between the machines on which HDS is implemented. Thus, there are no format conversion problems when moving between machines. HDS can write files in a private binary format (version 4), or be layered on top of HDF5 (version 5).

  13. Multifunctional Supramolecular Hybrid Materials Constructed from Hierarchical Self-Ordering of In Situ Generated Metal-Organic Framework (MOF) Nanoparticles.

    Science.gov (United States)

    Chaudhari, Abhijeet K; Han, Intaek; Tan, Jin-Chong

    2015-06-25

    A synergistic approach is described to engineer supramolecular hybrid materials based on metal-organic frameworks, encompassing HKUST-1 nanoparticles formed in situ, coexisting with an electrically conducting gel fiber network. Following findings were made: (a) multistimuli-responsive structural transformation via reversible sol-gel switching, and (b) radical conversion of a soft hybrid gel into a mechanically malleable, viscoelastic matter. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Hierarchical architecture of active knits

    Science.gov (United States)

    Abel, Julianna; Luntz, Jonathan; Brei, Diann

    2013-12-01

    Nature eloquently utilizes hierarchical structures to form the world around us. Applying the hierarchical architecture paradigm to smart materials can provide a basis for a new genre of actuators which produce complex actuation motions. One promising example of cellular architecture—active knits—provides complex three-dimensional distributed actuation motions with expanded operational performance through a hierarchically organized structure. The hierarchical structure arranges a single fiber of active material, such as shape memory alloys (SMAs), into a cellular network of interlacing adjacent loops according to a knitting grid. This paper defines a four-level hierarchical classification of knit structures: the basic knit loop, knit patterns, grid patterns, and restructured grids. Each level of the hierarchy provides increased architectural complexity, resulting in expanded kinematic actuation motions of active knits. The range of kinematic actuation motions are displayed through experimental examples of different SMA active knits. The results from this paper illustrate and classify the ways in which each level of the hierarchical knit architecture leverages the performance of the base smart material to generate unique actuation motions, providing necessary insight to best exploit this new actuation paradigm.

  15. Multi-Scale Entrainment of Coupled Neuronal Oscillations in Primary Auditory Cortex

    Science.gov (United States)

    O’Connell, M. N.; Barczak, A.; Ross, D.; McGinnis, T.; Schroeder, C. E.; Lakatos, P.

    2015-01-01

    Earlier studies demonstrate that when the frequency of rhythmic tone sequences or streams is task relevant, ongoing excitability fluctuations (oscillations) of neuronal ensembles in primary auditory cortex (A1) entrain to stimulation in a frequency dependent way that sharpens frequency tuning. The phase distribution across A1 neuronal ensembles at time points when attended stimuli are predicted to occur reflects the focus of attention along the spectral attribute of auditory stimuli. This study examined how neuronal activity is modulated if only the temporal features of rhythmic stimulus streams are relevant. We presented macaques with auditory clicks arranged in 33 Hz (gamma timescale) quintets, repeated at a 1.6 Hz (delta timescale) rate. Such multi-scale, hierarchically organized temporal structure is characteristic of vocalizations and other natural stimuli. Monkeys were required to detect and respond to deviations in the temporal pattern of gamma quintets. As expected, engagement in the auditory task resulted in the multi-scale entrainment of delta- and gamma-band neuronal oscillations across all of A1. Surprisingly, however, the phase-alignment, and thus, the physiological impact of entrainment differed across the tonotopic map in A1. In the region of 11–16 kHz representation, entrainment most often aligned high excitability oscillatory phases with task-relevant events in the input stream and thus resulted in response enhancement. In the remainder of the A1 sites, entrainment generally resulted in response suppression. Our data indicate that the suppressive effects were due to low excitability phase delta oscillatory entrainment and the phase amplitude coupling of delta and gamma oscillations. Regardless of the phase or frequency, entrainment appeared stronger in left A1, indicative of the hemispheric lateralization of auditory function. PMID:26696866

  16. Multi-scale entrainment of coupled neuronal oscillations in primary auditory cortex.

    Directory of Open Access Journals (Sweden)

    Monica Noelle O'Connell

    2015-12-01

    Full Text Available Earlier studies demonstrate that when the frequency of rhythmic tone sequences or streams is task relevant, ongoing excitability fluctuations (oscillations of neuronal ensembles in primary auditory cortex (A1 entrain to stimulation in a frequency dependent way that sharpens frequency tuning. The phase distribution across A1 neuronal ensembles at time points when attended stimuli are predicted to occur reflects the focus of attention along the spectral attribute of auditory stimuli. This study examined how neuronal activity is modulated if only the temporal features of rhythmic stimulus streams are relevant. We presented macaques with auditory clicks arranged in 33 Hz (gamma timescale quintets, repeated at a 1.6 Hz (delta timescale rate. Such multi-scale, hierarchically organized temporal structure is characteristic of vocalizations and other natural stimuli. Monkeys were required to detect and respond to deviations in the temporal pattern of gamma quintets. As expected, engagement in the auditory task resulted in the multi-scale entrainment of delta- and gamma-band neuronal oscillations across all of A1. Surprisingly, however, the phase-alignment, and thus, the physiological impact of entrainment differed across the tonotopic map in A1. In the region of 11-16 kHz representation, entrainment most often aligned high excitability oscillatory phases with task-relevant events in the input stream and thus resulted in response enhancement. In the remainder of the A1 sites, entrainment generally resulted in response suppression. Our data indicate that the suppressive effects were due to low excitability phase delta oscillatory entrainment and the phase amplitude coupling of delta and gamma oscillations. Regardless of the phase or frequency, entrainment appeared stronger in left A1, indicative of the hemispheric lateralization of auditory function.

  17. ZnO nanowires coated stainless steel meshes as hierarchical photocatalysts for catalytic photodegradation of four kinds of organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Fu-Hsiang; Lo, Wei-Ju [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan (China); Chang, Yu-Cheng, E-mail: ychang0127@gmail.com [Department of Materials Science and Engineering, Feng Chia University, Taichung, 40724, Taiwan (China); Guo, Jin-You; Chen, Chien-Ming [Department of Materials Science and Engineering, Feng Chia University, Taichung, 40724, Taiwan (China)

    2016-09-05

    ZnO nanostructures were grown on the stainless steel mesh substrates using an aqueous chemical growth method. The different additives (such as 1,3-diaminopropane and polyethyleneimine) can be used to control the morphology of ZnO nanostructures. ZnO nanowires exhibit very prominent green emission and week UV emission from defect and band gap in the cathodoluminescence spectrum, respectively. The different morphology of ZnO nanostructures on the stainless steel mesh substrates can be used to irradiate UV light for the photocatalytic degradation of four kinds of organic pollutants, such as methylene blue, rhodamine 6G, methyl orange, and 4-nitrophenol. The ZnO nanowires can provide a higher surface-to-volume ratio and stronger defect emission, resulting in their highest photocatalytic performance in 10 W UV light irradiation. The ZnO nanowire arrays on the stainless steel mesh substrates provide a large-scale, facile, low-cost, high surface area, and high photocatalytic efficiency, which shall be of significant value for practical applications of the decomposition of environment pollutants and reusing of wastewater treatment. - Highlights: • ZnO NWs were grown on the stainless steel mesh by aqueous chemical growth method. • Longer ZnO NW arrays have been grown at short reaction time (2 h). • ZnO NWs revealed green emission from surface defect in the CL spectrum. • The different morphologies of ZnO were evaluated organic pollutant degradation. • ZnO NWs were also exhibited great photocatalytic activity and reusability.

  18. Formation of microcraters and hierarchically-organized surface structures in TiNi shape memory alloy irradiated with a low-energy, high-current electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Meisner, L. L., E-mail: llm@ispms.tsc.ru; Meisner, S. N., E-mail: myp@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Markov, A. B., E-mail: a.markov@hq.tsc.ru; Ozur, G. E., E-mail: vrotshtein@yahoo.com; Yakovlev, E. V., E-mail: msn@ispms.tsc.ru [Institute of High Current Electronics SB RAS, Tomsk, 634055 (Russian Federation); Rotshtein, V. P., E-mail: yakovev@lve.hcei.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Tomsk State Pedagogical University, Tomsk, 634050 (Russian Federation); Gudimova, E. Yu., E-mail: ozur@lve.hcei.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)

    2015-10-27

    The regularities of surface cratering in TiNi alloy irradiated with a low-energy, high-current electron beam (LEHCEB) in dependence on energy density and number of pulses are studied. LEHCEB processing of TiNi samples was carried out using RITM-SP facility. Energy density E{sub s} was varied from 1 to 5 J/cm{sup 2}, pulse duration was 2.5–3.0 μs, the number of pulses n = 1–128. The dominant role of non-metallic inclusions [mainly, TiC(O)] in the nucleation of microcraters was found. It was revealed that at small number of pulses (n = 2), an increase in energy density leads both to increasing average diameter and density of microcraters. An increase in the number of pulses leads to a monotonic decrease in density of microcraters, and, therefore, that of the proportion of the area occupied by microcraters, as well as a decrease in the surface roughness. The multiple LEHCEB melting of TiNi alloy in crater-free modes enables to form quasi-periodical, hierarchically-organized microsized surface structures.

  19. Hierarchical self-assembly: Self-organized nanostructures in a nematically ordered matrix of self-assembled polymeric chains

    Science.gov (United States)

    Mubeena, Shaikh; Chatterji, Apratim

    2015-03-01

    We report many different nanostructures which are formed when model nanoparticles of different sizes (diameter σn) are allowed to aggregate in a background matrix of semiflexible self-assembled polymeric wormlike micellar chains. The different nanostructures are formed by the dynamical arrest of phase-separating mixtures of micellar monomers and nanoparticles. The different morphologies obtained are the result of an interplay of the available free volume, the elastic energy of deformation of polymers, the density (chemical potential) of the nanoparticles in the polymer matrix, and, of course, the ratio of the size of self-assembling nanoparticles and self-avoidance diameter of polymeric chains. We have used a hybrid semi-grand-canonical Monte Carlo simulation scheme to obtain the (nonequilibrium) phase diagram of the self-assembled nanostructures. We observe rodlike structures of nanoparticles which get self-assembled in the gaps between the nematically ordered chains, as well as percolating gel-like network of conjoined nanotubes. We also find a totally unexpected interlocked crystalline phase of nanoparticles and monomers, in which each crystal plane of nanoparticles is separated by planes of perfectly organized polymer chains. We identified the condition which leads to such interlocked crystal structure. We suggest experimental possibilities of how the results presented in this paper could be used to obtain different nanostructures in the laboratory.

  20. Hierarchical self-assembly: Self-organized nanostructures in a nematically ordered matrix of self-assembled polymeric chains.

    Science.gov (United States)

    Mubeena, Shaikh; Chatterji, Apratim

    2015-03-01

    We report many different nanostructures which are formed when model nanoparticles of different sizes (diameter σn) are allowed to aggregate in a background matrix of semiflexible self-assembled polymeric wormlike micellar chains. The different nanostructures are formed by the dynamical arrest of phase-separating mixtures of micellar monomers and nanoparticles. The different morphologies obtained are the result of an interplay of the available free volume, the elastic energy of deformation of polymers, the density (chemical potential) of the nanoparticles in the polymer matrix, and, of course, the ratio of the size of self-assembling nanoparticles and self-avoidance diameter of polymeric chains. We have used a hybrid semi-grand-canonical Monte Carlo simulation scheme to obtain the (nonequilibrium) phase diagram of the self-assembled nanostructures. We observe rodlike structures of nanoparticles which get self-assembled in the gaps between the nematically ordered chains, as well as percolating gel-like network of conjoined nanotubes. We also find a totally unexpected interlocked crystalline phase of nanoparticles and monomers, in which each crystal plane of nanoparticles is separated by planes of perfectly organized polymer chains. We identified the condition which leads to such interlocked crystal structure. We suggest experimental possibilities of how the results presented in this paper could be used to obtain different nanostructures in the laboratory.

  1. Auditory Imagery: Empirical Findings

    Science.gov (United States)

    Hubbard, Timothy L.

    2010-01-01

    The empirical literature on auditory imagery is reviewed. Data on (a) imagery for auditory features (pitch, timbre, loudness), (b) imagery for complex nonverbal auditory stimuli (musical contour, melody, harmony, tempo, notational audiation, environmental sounds), (c) imagery for verbal stimuli (speech, text, in dreams, interior monologue), (d)…

  2. Hierarchically Flower-like N-Doped Porous Carbon Materials Derived from an Explosive 3-Fold Interpenetrating Diamondoid Copper Metal-Organic Framework for a Supercapacitor.

    Science.gov (United States)

    Li, Zuo-Xi; Zou, Kang-Yu; Zhang, Xue; Han, Tong; Yang, Ying

    2016-07-05

    A peculiar copper metal-organic framework (Cu-MOF) was synthesized by a self-assembly method, which presents a 3-fold interpenetrating diamondoid net based on the square-planar Cu(II) node. Although it exhibits a high degree of interpenetration, the Cu-MOF still exhibits a one-dimensional channel, which provides a template for constructing porous materials through the "precursor" strategy. Furthermore, the explosive ClO4(-) ion, which resided in the channel, could induce the quick decomposition of organic ingredients and release a huge amount of gas, which is beneficial for the porosity of postsynthetic materials. Significantly, we first utilize this explosive MOF to prepare a series of Cu@C composites through the calcination-thermolysis method at different temperatures, which contain copper particles exhibiting various shapes and combinations with the carbon substrate. Considering the hole-forming effect of copper particles, Cu@C composites were etched by HCl to afford a sequence of hierarchically flower-like N-doped porous carbon materials (NPCs), which retain the original morphology of the Cu-MOF. Interestingly, NPC-900, originating from the calcination of the Cu-MOF at 900 °C, exhibits a more regular flower-like morphology, the largest specific surface area, abundant porosities, and multiple nitrogen functionalities. The remarkable specific capacitances are 138 F g(-1) at 5 mV s(-1) and 149 F g(-1) at 0.5 A g(-1) for the NPC-900 electrode in a 6 M potassium hydroxide aqueous solution. Moreover, the retention of capacitance remains 86.8% (125 F g(-1)) at 1 A g(-1) over 2000 cycles, which displays good chemical stability. These findings suggest that NPC-900 can be applied as a suitable electrode for a supercapacitor.

  3. Peripheral Auditory Mechanisms

    CERN Document Server

    Hall, J; Hubbard, A; Neely, S; Tubis, A

    1986-01-01

    How weIl can we model experimental observations of the peripheral auditory system'? What theoretical predictions can we make that might be tested'? It was with these questions in mind that we organized the 1985 Mechanics of Hearing Workshop, to bring together auditory researchers to compare models with experimental observations. Tbe workshop forum was inspired by the very successful 1983 Mechanics of Hearing Workshop in Delft [1]. Boston University was chosen as the site of our meeting because of the Boston area's role as a center for hearing research in this country. We made a special effort at this meeting to attract students from around the world, because without students this field will not progress. Financial support for the workshop was provided in part by grant BNS- 8412878 from the National Science Foundation. Modeling is a traditional strategy in science and plays an important role in the scientific method. Models are the bridge between theory and experiment. Tbey test the assumptions made in experim...

  4. Synthesis of Hierarchically Structured Hybrid Materials by Controlled Self-Assembly of Metal-Organic Framework with Mesoporous Silica for CO2 Adsorption.

    Science.gov (United States)

    Chen, Chong; Li, Bingxue; Zhou, Lijin; Xia, Zefeng; Feng, Nengjie; Ding, Jing; Wang, Lei; Wan, Hui; Guan, Guofeng

    2017-07-12

    The HKUST-1@SBA-15 composites with hierarchical pore structure were constructed by in situ self-assembly of metal-organic framework (MOF) with mesoporous silica. The structure directing role of SBA-15 had an obvious impact on the growth of MOF crystals, which in turn affected the morphologies and structural properties of the composites. The pristine HKUST-1 and the composites with different content of SBA-15 were characterized by XRD, N2 adsorption-desorption, SEM, TEM, FT-IR, TG, XPS, and CO2-TPD techniques. It was found that the composites were assembled by oriented growth of MOF nanocrystals on the surfaces of SBA-15 matrix. The interactions between surface silanol groups and metal centers induced structural changes and resulted in the increases in surface areas as well as micropore volumes of hybrid materials. Besides, the additional constraints from SBA-15 also restrained the expansion of HKUST-1, contributing to their smaller crystal sizes in the composites. The adsorption isotherms of CO2 on the materials were measured and applied to calculate the isosteric heats of adsorption. The HS-1 composite exhibited an increase of 15.9% in CO2 uptake capacity compared with that of HKUST-1. Moreover, its higher isosteric heats of CO2 adsorption indicated the stronger interactions between the surfaces and CO2 molecules. The adsorption rate of the composite was also improved due to the introduction of mesopores. Ten cycles of CO2 adsorption-desorption experiments implied that the HS-1 had excellent reversibility of CO2 adsorption. This study was intended to provide the possibility of assembling new composites with tailored properties based on MOF and mesoporous silica to satisfy the requirements of various applications.

  5. Hierarchical Network Design

    DEFF Research Database (Denmark)

    Thomadsen, Tommy

    2005-01-01

    of different types of hierarchical networks. This is supplemented by a review of ring network design problems and a presentation of a model allowing for modeling most hierarchical networks. We use methods based on linear programming to design the hierarchical networks. Thus, a brief introduction to the various....... The thesis investigates models for hierarchical network design and methods used to design such networks. In addition, ring network design is considered, since ring networks commonly appear in the design of hierarchical networks. The thesis introduces hierarchical networks, including a classification scheme...... linear programming based methods is included. The thesis is thus suitable as a foundation for study of design of hierarchical networks. The major contribution of the thesis consists of seven papers which are included in the appendix. The papers address hierarchical network design and/or ring network...

  6. Auditory imagery: empirical findings.

    Science.gov (United States)

    Hubbard, Timothy L

    2010-03-01

    The empirical literature on auditory imagery is reviewed. Data on (a) imagery for auditory features (pitch, timbre, loudness), (b) imagery for complex nonverbal auditory stimuli (musical contour, melody, harmony, tempo, notational audiation, environmental sounds), (c) imagery for verbal stimuli (speech, text, in dreams, interior monologue), (d) auditory imagery's relationship to perception and memory (detection, encoding, recall, mnemonic properties, phonological loop), and (e) individual differences in auditory imagery (in vividness, musical ability and experience, synesthesia, musical hallucinosis, schizophrenia, amusia) are considered. It is concluded that auditory imagery (a) preserves many structural and temporal properties of auditory stimuli, (b) can facilitate auditory discrimination but interfere with auditory detection, (c) involves many of the same brain areas as auditory perception, (d) is often but not necessarily influenced by subvocalization, (e) involves semantically interpreted information and expectancies, (f) involves depictive components and descriptive components, (g) can function as a mnemonic but is distinct from rehearsal, and (h) is related to musical ability and experience (although the mechanisms of that relationship are not clear).

  7. Hierarchical analysis of acceptable use policies

    Directory of Open Access Journals (Sweden)

    P. A. Laughton

    2008-01-01

    Full Text Available Acceptable use policies (AUPs are vital tools for organizations to protect themselves and their employees from misuse of computer facilities provided. A well structured, thorough AUP is essential for any organization. It is impossible for an effective AUP to deal with every clause and remain readable. For this reason, some sections of an AUP carry more weight than others, denoting importance. The methodology used to develop the hierarchical analysis is a literature review, where various sources were consulted. This hierarchical approach to AUP analysis attempts to highlight important sections and clauses dealt with in an AUP. The emphasis of the hierarchal analysis is to prioritize the objectives of an AUP.

  8. Hierarchical Multiagent Reinforcement Learning

    Science.gov (United States)

    2004-01-25

    In this paper, we investigate the use of hierarchical reinforcement learning (HRL) to speed up the acquisition of cooperative multiagent tasks. We...introduce a hierarchical multiagent reinforcement learning (RL) framework and propose a hierarchical multiagent RL algorithm called Cooperative HRL. In

  9. Reconsidering Tonotopic Maps in the Auditory Cortex and Lemniscal Auditory Thalamus in Mice.

    Science.gov (United States)

    Tsukano, Hiroaki; Horie, Masao; Ohga, Shinpei; Takahashi, Kuniyuki; Kubota, Yamato; Hishida, Ryuichi; Takebayashi, Hirohide; Shibuki, Katsuei

    2017-01-01

    The auditory thalamus and auditory cortex (AC) are pivotal structures in the central auditory system. However, the thalamocortical mechanisms of processing sounds are largely unknown. Investigation of this process benefits greatly from the use of mice because the mouse is a powerful animal model in which various experimental techniques, especially genetic tools, can be applied. However, the use of mice has been limited in auditory research, and thus even basic anatomical knowledge of the mouse central auditory system has not been sufficiently collected. Recently, optical imaging combined with morphological analyses has enabled the elucidation of detailed anatomical properties of the mouse auditory system. These techniques have uncovered fine AC maps with multiple frequency-organized regions, each of which receives point-to-point thalamocortical projections from different origins inside the lemniscal auditory thalamus, the ventral division of the medial geniculate body (MGv). This precise anatomy now provides a platform for physiological research. In this mini review article, we summarize these recent achievements that will facilitate physiological investigations in the mouse auditory system.

  10. Hierarchical Identity-Based Lossy Trapdoor Functions

    CERN Document Server

    Escala, Alex; Libert, Benoit; Rafols, Carla

    2012-01-01

    Lossy trapdoor functions, introduced by Peikert and Waters (STOC'08), have received a lot of attention in the last years, because of their wide range of applications in theoretical cryptography. The notion has been recently extended to the identity-based scenario by Bellare et al. (Eurocrypt'12). We provide one more step in this direction, by considering the notion of hierarchical identity-based lossy trapdoor functions (HIB-LTDFs). Hierarchical identity-based cryptography generalizes identitybased cryptography in the sense that identities are organized in a hierarchical way; a parent identity has more power than its descendants, because it can generate valid secret keys for them. Hierarchical identity-based cryptography has been proved very useful both for practical applications and to establish theoretical relations with other cryptographic primitives. In order to realize HIB-LTDFs, we first build a weakly secure hierarchical predicate encryption scheme. This scheme, which may be of independent interest, is...

  11. Hierarchical Network Design

    DEFF Research Database (Denmark)

    Thomadsen, Tommy

    2005-01-01

    Communication networks are immensely important today, since both companies and individuals use numerous services that rely on them. This thesis considers the design of hierarchical (communication) networks. Hierarchical networks consist of layers of networks and are well-suited for coping...... the clusters. The design of hierarchical networks involves clustering of nodes, hub selection, and network design, i.e. selection of links and routing of ows. Hierarchical networks have been in use for decades, but integrated design of these networks has only been considered for very special types of networks....... The thesis investigates models for hierarchical network design and methods used to design such networks. In addition, ring network design is considered, since ring networks commonly appear in the design of hierarchical networks. The thesis introduces hierarchical networks, including a classification scheme...

  12. Ca(II) doped β-In2S3 hierarchical structures for photocatalytic hydrogen generation and organic dye degradation under visible light irradiation.

    Science.gov (United States)

    Yang, Shuang; Xu, Cheng-Yan; Zhang, Bao-You; Yang, Li; Hu, Sheng-Peng; Zhen, Liang

    2017-04-01

    Hierarchical structures assembled by two-dimensional (2D) nanosheets could inherit the characteristics of nanosheets and acquire additional advantages from the unique secondary architectures, which would have important influences on the photocatalytic properties of semiconductor nanomaterials. In this work, we successfully synthesized Ca(II) doped β-In2S3 hierarchical structures stacked by thin nanosheets by a simple solution chemical process. The effects of reaction temperature and Ca(2+) concentration on the size and morphology of the products were systematically investigated. The photocatalytic applications of the β-In2S3 hierarchical structures were evaluated for hydrogen production and degradation of Rhodamine B (RhB) under visible light irradiation (λ>420nm). The β-In2S3 hierarchical structures showed promising activity towards photocatalytic hydrogen production (145.0μmolg(-1)h(-1)) and RhB solution (1×10(-5)M) was completely degraded within 100min under visible light irradiation.

  13. Facile synthesis of BiOI in hierarchical nanostructure preparation and its photocatalytic application to organic dye removal and biocidal effect of bacteria.

    Science.gov (United States)

    Long, Yang; Wang, Yi; Zhang, Dun; Ju, Peng; Sun, Yan

    2016-11-01

    Novel BiOI hierarchical nanostructures with porous architecture was prepared at room temperature by an economical, facile and rapid route. The coupling adsorption and degradation efficiency of rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) could achieve 98.7%, 43.2%, 76.9% within 180min in the presence of BiOI, respectively. BiOI hierarchical nanostructures also exhibit excellent effective biocidal performances, and the disinfection rate of the typical biofouling bacteria Bacillus sp. and Pseudoalteromonas sp. could reach 99.9% and 99.8% in 60min, respectively. The circulate photocatalytic degradation of RhB experiment verified the good stability and reusability of BiOI hierarchical nanostructures. Based on active specie trapping experiments, the superoxide radicals (O2(-)) and holes (h(+)) were proved to be the main reactive species in the BiOI-based system. The obviously enhanced coupling adsorption and photocatalytic degradation performance of BiOI hierarchical nanostructures could be mainly attributed to the large surface area (64.5m(2)/g), negatively charged surface and the intrinsic electron structure. This study provides a new strategy to develop novel photocatalysts for water treatment and marine antifouling. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Resizing Auditory Communities

    DEFF Research Database (Denmark)

    Kreutzfeldt, Jacob

    2012-01-01

    Heard through the ears of the Canadian composer and music teacher R. Murray Schafer the ideal auditory community had the shape of a village. Schafer’s work with the World Soundscape Project in the 70s represent an attempt to interpret contemporary environments through musical and auditory...

  15. Linking topography to tonotopy in the mouse auditory thalamocortical circuit

    DEFF Research Database (Denmark)

    Hackett, Troy A; Rinaldi Barkat, Tania; O'Brien, Barbara M J;

    2011-01-01

    The mouse sensory neocortex is reported to lack several hallmark features of topographic organization such as ocular dominance and orientation columns in primary visual cortex or fine-scale tonotopy in primary auditory cortex (AI). Here, we re-examined the question of auditory functional topography...

  16. Hierarchical modularity in human brain functional networks

    CERN Document Server

    Meunier, D; Fornito, A; Ersche, K D; Bullmore, E T; 10.3389/neuro.11.037.2009

    2010-01-01

    The idea that complex systems have a hierarchical modular organization originates in the early 1960s and has recently attracted fresh support from quantitative studies of large scale, real-life networks. Here we investigate the hierarchical modular (or "modules-within-modules") decomposition of human brain functional networks, measured using functional magnetic resonance imaging (fMRI) in 18 healthy volunteers under no-task or resting conditions. We used a customized template to extract networks with more than 1800 regional nodes, and we applied a fast algorithm to identify nested modular structure at several hierarchical levels. We used mutual information, 0 < I < 1, to estimate the similarity of community structure of networks in different subjects, and to identify the individual network that is most representative of the group. Results show that human brain functional networks have a hierarchical modular organization with a fair degree of similarity between subjects, I=0.63. The largest 5 modules at ...

  17. Auditory-motor learning influences auditory memory for music.

    Science.gov (United States)

    Brown, Rachel M; Palmer, Caroline

    2012-05-01

    In two experiments, we investigated how auditory-motor learning influences performers' memory for music. Skilled pianists learned novel melodies in four conditions: auditory only (listening), motor only (performing without sound), strongly coupled auditory-motor (normal performance), and weakly coupled auditory-motor (performing along with auditory recordings). Pianists' recognition of the learned melodies was better following auditory-only or auditory-motor (weakly coupled and strongly coupled) learning than following motor-only learning, and better following strongly coupled auditory-motor learning than following auditory-only learning. Auditory and motor imagery abilities modulated the learning effects: Pianists with high auditory imagery scores had better recognition following motor-only learning, suggesting that auditory imagery compensated for missing auditory feedback at the learning stage. Experiment 2 replicated the findings of Experiment 1 with melodies that contained greater variation in acoustic features. Melodies that were slower and less variable in tempo and intensity were remembered better following weakly coupled auditory-motor learning. These findings suggest that motor learning can aid performers' auditory recognition of music beyond auditory learning alone, and that motor learning is influenced by individual abilities in mental imagery and by variation in acoustic features.

  18. Growth of self-organized hierarchical ZnO nanoarchitectures by a simple In/In2S3 controlled thermal evaporation process.

    Science.gov (United States)

    Shen, Guozhen; Bando, Yoshio; Lee, Cheol-Jin

    2005-06-02

    Novel hierarchical ZnO nanoarchitectures, such as microtrepangs, microbelts, nanoflowers, nanocombs, nanowheels, and nanofans assembled by ZnO nanocones, nanobowling pins, nanobottles, nanoarrows, and nanonails, have had their growth controlled by the thermal evaporation of Zn and a mixture of In and In2S3. Both the morphologies of the products and their construction units could be efficiently controlled by simple adjustment of the weight ratio of In/In2S3. The phase structure, morphologies, and photoluminescence properties of the ZnO products were investigated by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and photoluminescence spectroscopy. These novel hierarchical ZnO nanoarchitectures may be attractive building blocks for creating optical or other nanodevices.

  19. Behavioral modulation of neural encoding of click-trains in the primary and nonprimary auditory cortex of cats.

    Science.gov (United States)

    Dong, Chao; Qin, Ling; Zhao, Zhenling; Zhong, Renjia; Sato, Yu

    2013-08-07

    Neural representation of acoustic stimuli in the mammal auditory cortex (AC) has been extensively studied using anesthetized or awake nonbehaving animals. Recently, several studies have shown that active engagement in an auditory behavioral task can substantially change the neuron response properties compared with when animals were passively listening to the same sounds; however, these studies mainly investigated the effect of behavioral state on the primary auditory cortex and the reported effects were inconsistent. Here, we examined the single-unit spike activities in both the primary and nonprimary areas along the dorsal-to-ventral direction of the cat's AC, when the cat was actively discriminating click-trains at different repetition rates and when it was passively listening to the same stimuli. We found that the changes due to task engagement were heterogeneous in the primary AC; some neurons showed significant increases in driven firing rate, others showed decreases. But in the nonprimary AC, task engagement predominantly enhanced the neural responses, resulting in a substantial improvement of the neural discriminability of click-trains. Additionally, our results revealed that neural responses synchronizing to click-trains gradually decreased along the dorsal-to-ventral direction of cat AC, while nonsynchronizing responses remained less changed. The present study provides new insights into the hierarchical organization of AC along the dorsal-to-ventral direction and highlights the importance of using behavioral animals to investigate the later stages of cortical processing.

  20. Weather regimes over Senegal during the summer monsoon season using self-organizing maps and hierarchical ascendant classification. Part II: interannual time scale

    Energy Technology Data Exchange (ETDEWEB)

    Gueye, A.K. [ESP, UCAD, Dakar (Senegal); Janicot, Serge; Sultan, Benjamin [LOCEAN/IPSL, IRD, Universite Pierre et Marie Curie, Paris cedex 05 (France); Niang, A. [LTI, ESP/UCAD, Dakar (Senegal); Sawadogo, S. [LTI, EPT, Thies (Senegal); Diongue-Niang, A. [ANACIM, Dakar (Senegal); Thiria, S. [LOCEAN/IPSL, UPMC, Paris (France)

    2012-11-15

    The aim of this work is to define over the period 1979-2002 the main synoptic weather regimes relevant for understanding the daily variability of rainfall during the summer monsoon season over Senegal. ''Interannual'' synoptic weather regimes are defined by removing the influence of the mean 1979-2002 seasonal cycle. This is different from Part I where the seasonal evolution of each year was removed, then removing also the contribution of interannual variability. As in Part I, the self-organizing maps approach, a clustering methodology based on non-linear artificial neural network, is combined with a hierarchical ascendant classification to compute these regimes. Nine weather regimes are identified using the mean sea level pressure and 850 hPa wind field as variables. The composite circulation patterns of all these nine weather regimes are very consistent with the associated anomaly patterns of precipitable water, mid-troposphere vertical velocity and rainfall. They are also consistent with the distribution of rainfall extremes. These regimes have been then gathered into different groups. A first group of four regimes is included in an inner circuit and is characterized by a modulation of the semi-permanent trough located along the western coast of West Africa and an opposite modulation on the east. This circuit is important because it associates the two wettest and highly persistent weather regimes over Senegal with the driest and the most persistent one. One derivation of this circuit is highlighted, including the two driest regimes and the most persistent one, what can provide important dry sequences occurrence. An exit of this circuit is characterised by a filling of the Saharan heat low. An entry into the main circuit includes a southward location of the Saharan heat low followed by its deepening. The last weather regime is isolated from the other ones and it has no significant impact on Senegal. It is present in June and September, and

  1. Auditory Integration Training

    Directory of Open Access Journals (Sweden)

    Zahra Jafari

    2002-07-01

    Full Text Available Auditory integration training (AIT is a hearing enhancement training process for sensory input anomalies found in individuals with autism, attention deficit hyperactive disorder, dyslexia, hyperactivity, learning disability, language impairments, pervasive developmental disorder, central auditory processing disorder, attention deficit disorder, depressin, and hyperacute hearing. AIT, recently introduced in the United States, and has received much notice of late following the release of The Sound of a Moracle, by Annabel Stehli. In her book, Mrs. Stehli describes before and after auditory integration training experiences with her daughter, who was diagnosed at age four as having autism.

  2. Hierarchical structure of biological systems

    Science.gov (United States)

    Alcocer-Cuarón, Carlos; Rivera, Ana L; Castaño, Victor M

    2014-01-01

    A general theory of biological systems, based on few fundamental propositions, allows a generalization of both Wierner and Berthalanffy approaches to theoretical biology. Here, a biological system is defined as a set of self-organized, differentiated elements that interact pair-wise through various networks and media, isolated from other sets by boundaries. Their relation to other systems can be described as a closed loop in a steady-state, which leads to a hierarchical structure and functioning of the biological system. Our thermodynamical approach of hierarchical character can be applied to biological systems of varying sizes through some general principles, based on the exchange of energy information and/or mass from and within the systems. PMID:24145961

  3. Automatic Hierarchical Color Image Classification

    Directory of Open Access Journals (Sweden)

    Jing Huang

    2003-02-01

    Full Text Available Organizing images into semantic categories can be extremely useful for content-based image retrieval and image annotation. Grouping images into semantic classes is a difficult problem, however. Image classification attempts to solve this hard problem by using low-level image features. In this paper, we propose a method for hierarchical classification of images via supervised learning. This scheme relies on using a good low-level feature and subsequently performing feature-space reconfiguration using singular value decomposition to reduce noise and dimensionality. We use the training data to obtain a hierarchical classification tree that can be used to categorize new images. Our experimental results suggest that this scheme not only performs better than standard nearest-neighbor techniques, but also has both storage and computational advantages.

  4. Auditory Responses of Infants

    Science.gov (United States)

    Watrous, Betty Springer; And Others

    1975-01-01

    Forty infants, 3- to 12-months-old, participated in a study designed to differentiate the auditory response characteristics of normally developing infants in the age ranges 3 - 5 months, 6 - 8 months, and 9 - 12 months. (Author)

  5. Treatment Protocols as Hierarchical Structures

    Science.gov (United States)

    Ben-Bassat, Moshe; Carlson, Richard W.; Puri, Vinod K.; Weil, Max Harry

    1978-01-01

    We view a treatment protocol as a hierarchical structure of therapeutic modules. The lowest level of this structure consists of individual therapeutic actions. Combinations of individual actions define higher level modules, which we call routines. Routines are designed to manage limited clinical problems, such as the routine for fluid loading to correct hypovolemia. Combinations of routines and additional actions, together with comments, questions, or precautions organized in a branching logic, in turn, define the treatment protocol for a given disorder. Adoption of this modular approach may facilitate the formulation of treatment protocols, since the physician is not required to prepare complex flowcharts. This hierarchical approach also allows protocols to be updated and modified in a flexible manner. By use of such a standard format, individual components may be fitted together to create protocols for multiple disorders. The technique is suited for computer implementation. We believe that this hierarchical approach may facilitate standarization of patient care as well as aid in clinical teaching. A protocol for acute pancreatitis is used to illustrate this technique.

  6. Auditory hallucinations induced by trazodone.

    Science.gov (United States)

    Shiotsuki, Ippei; Terao, Takeshi; Ishii, Nobuyoshi; Hatano, Koji

    2014-04-03

    A 26-year-old female outpatient presenting with a depressive state suffered from auditory hallucinations at night. Her auditory hallucinations did not respond to blonanserin or paliperidone, but partially responded to risperidone. In view of the possibility that her auditory hallucinations began after starting trazodone, trazodone was discontinued, leading to a complete resolution of her auditory hallucinations. Furthermore, even after risperidone was decreased and discontinued, her auditory hallucinations did not recur. These findings suggest that trazodone may induce auditory hallucinations in some susceptible patients.

  7. Green self-assembly of zein-conjugated ZnO/Cd(OH)Cl hierarchical nanocomposites with high cytotoxicity and immune organs targeting

    Science.gov (United States)

    Wang, Hua-Jie; Cao, Ying; Wang, Cai-Feng; Cui, Shi-Zhong; Mi, Li-Wei; Miyazawa, Teruo

    2016-04-01

    Inorganic nanomedicines in the fight against cancer have progressed rapidly during recent years, with the synergistic advantages of multifunctional nanosystems compared to single component. Herein, a drug-combination opinion was introduced into “nanomedicine” based on the understanding of Trojan horse-anti-tumor mechanism of inorganic nano-medicines. Moreover, we reported the green and facile synthesis route of mono-dispersed and rod-like zein-conjugated ZnO/Cd(OH)Cl hierarchical nanocomposites. We found that the nanocomposites exhibited high-efficiency killing ability to tumor cells through lipid peroxidation mediated-membrane disintegration route. The safety studies in BALB/c mice didn’t detect injection anaphylaxis, hemolysis and cytotoxicity. More interestingly, the nano-composites could specially accumulate in liver and kidney, which will be helpful for targeting cure to these regional cancers.

  8. Hierarchical organization of fluxes in Escherichia coli metabolic network: using flux coupling analysis for understanding the physiological properties of metabolic genes.

    Science.gov (United States)

    Hosseini, Zhaleh; Marashi, Sayed-Amir

    2015-05-01

    Flux coupling analysis is a method for investigating the connections between reactions of metabolic networks. Here, we construct the hierarchical flux coupling graph for the reactions of the Escherichia coli metabolic network model to determine the level of each reaction in the graph. This graph is constructed based on flux coupling analysis of metabolic network: if zero flux through reaction a results in zero flux through reaction b (and not vice versa), then reaction a is located at the top of reaction b in the flux coupling graph. We show that in general, more important, older and essential reactions are located at the top of the graph. Strikingly, genes corresponding to these reactions are found to be the genes which are most regulated.

  9. Micromechanics of hierarchical materials

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon, Jr.

    2012-01-01

    A short overview of micromechanical models of hierarchical materials (hybrid composites, biomaterials, fractal materials, etc.) is given. Several examples of the modeling of strength and damage in hierarchical materials are summarized, among them, 3D FE model of hybrid composites...... with nanoengineered matrix, fiber bundle model of UD composites with hierarchically clustered fibers and 3D multilevel model of wood considered as a gradient, cellular material with layered composite cell walls. The main areas of research in micromechanics of hierarchical materials are identified, among them......, the investigations of the effects of load redistribution between reinforcing elements at different scale levels, of the possibilities to control different material properties and to ensure synergy of strengthening effects at different scale levels and using the nanoreinforcement effects. The main future directions...

  10. Hierarchical auxetic mechanical metamaterials.

    Science.gov (United States)

    Gatt, Ruben; Mizzi, Luke; Azzopardi, Joseph I; Azzopardi, Keith M; Attard, Daphne; Casha, Aaron; Briffa, Joseph; Grima, Joseph N

    2015-02-11

    Auxetic mechanical metamaterials are engineered systems that exhibit the unusual macroscopic property of a negative Poisson's ratio due to sub-unit structure rather than chemical composition. Although their unique behaviour makes them superior to conventional materials in many practical applications, they are limited in availability. Here, we propose a new class of hierarchical auxetics based on the rotating rigid units mechanism. These systems retain the enhanced properties from having a negative Poisson's ratio with the added benefits of being a hierarchical system. Using simulations on typical hierarchical multi-level rotating squares, we show that, through design, one can control the extent of auxeticity, degree of aperture and size of the different pores in the system. This makes the system more versatile than similar non-hierarchical ones, making them promising candidates for industrial and biomedical applications, such as stents and skin grafts.

  11. Introduction into Hierarchical Matrices

    KAUST Repository

    Litvinenko, Alexander

    2013-12-05

    Hierarchical matrices allow us to reduce computational storage and cost from cubic to almost linear. This technique can be applied for solving PDEs, integral equations, matrix equations and approximation of large covariance and precision matrices.

  12. Hierarchical Auxetic Mechanical Metamaterials

    Science.gov (United States)

    Gatt, Ruben; Mizzi, Luke; Azzopardi, Joseph I.; Azzopardi, Keith M.; Attard, Daphne; Casha, Aaron; Briffa, Joseph; Grima, Joseph N.

    2015-02-01

    Auxetic mechanical metamaterials are engineered systems that exhibit the unusual macroscopic property of a negative Poisson's ratio due to sub-unit structure rather than chemical composition. Although their unique behaviour makes them superior to conventional materials in many practical applications, they are limited in availability. Here, we propose a new class of hierarchical auxetics based on the rotating rigid units mechanism. These systems retain the enhanced properties from having a negative Poisson's ratio with the added benefits of being a hierarchical system. Using simulations on typical hierarchical multi-level rotating squares, we show that, through design, one can control the extent of auxeticity, degree of aperture and size of the different pores in the system. This makes the system more versatile than similar non-hierarchical ones, making them promising candidates for industrial and biomedical applications, such as stents and skin grafts.

  13. Applied Bayesian Hierarchical Methods

    CERN Document Server

    Congdon, Peter D

    2010-01-01

    Bayesian methods facilitate the analysis of complex models and data structures. Emphasizing data applications, alternative modeling specifications, and computer implementation, this book provides a practical overview of methods for Bayesian analysis of hierarchical models.

  14. Programming with Hierarchical Maps

    DEFF Research Database (Denmark)

    Ørbæk, Peter

    This report desribes the hierarchical maps used as a central data structure in the Corundum framework. We describe its most prominent features, ague for its usefulness and briefly describe some of the software prototypes implemented using the technology....

  15. Catalysis with hierarchical zeolites

    DEFF Research Database (Denmark)

    Holm, Martin Spangsberg; Taarning, Esben; Egeblad, Kresten

    2011-01-01

    Hierarchical (or mesoporous) zeolites have attracted significant attention during the first decade of the 21st century, and so far this interest continues to increase. There have already been several reviews giving detailed accounts of the developments emphasizing different aspects of this research...... topic. Until now, the main reason for developing hierarchical zeolites has been to achieve heterogeneous catalysts with improved performance but this particular facet has not yet been reviewed in detail. Thus, the present paper summaries and categorizes the catalytic studies utilizing hierarchical...... zeolites that have been reported hitherto. Prototypical examples from some of the different categories of catalytic reactions that have been studied using hierarchical zeolite catalysts are highlighted. This clearly illustrates the different ways that improved performance can be achieved with this family...

  16. Musical training orchestrates coordinated neuroplasticity in auditory brainstem and cortex to counteract age-related declines in categorical vowel perception.

    Science.gov (United States)

    Bidelman, Gavin M; Alain, Claude

    2015-01-21

    Musicianship in early life is associated with pervasive changes in brain function and enhanced speech-language skills. Whether these neuroplastic benefits extend to older individuals more susceptible to cognitive decline, and for whom plasticity is weaker, has yet to be established. Here, we show that musical training offsets declines in auditory brain processing that accompanying normal aging in humans, preserving robust speech recognition late into life. We recorded both brainstem and cortical neuroelectric responses in older adults with and without modest musical training as they classified speech sounds along an acoustic-phonetic continuum. Results reveal higher temporal precision in speech-evoked responses at multiple levels of the auditory system in older musicians who were also better at differentiating phonetic categories. Older musicians also showed a closer correspondence between neural activity and perceptual performance. This suggests that musicianship strengthens brain-behavior coupling in the aging auditory system. Last, "neurometric" functions derived from unsupervised classification of neural activity established that early cortical responses could accurately predict listeners' psychometric speech identification and, more critically, that neurometric profiles were organized more categorically in older musicians. We propose that musicianship offsets age-related declines in speech listening by refining the hierarchical interplay between subcortical/cortical auditory brain representations, allowing more behaviorally relevant information carried within the neural code, and supplying more faithful templates to the brain mechanisms subserving phonetic computations. Our findings imply that robust neuroplasticity conferred by musical training is not restricted by age and may serve as an effective means to bolster speech listening skills that decline across the lifespan. Copyright © 2015 the authors 0270-6474/15/351240-10$15.00/0.

  17. Music and the auditory brain: where is the connection?

    Directory of Open Access Journals (Sweden)

    Israel eNelken

    2011-09-01

    Full Text Available Sound processing by the auditory system is understood in unprecedented details, even compared with sensory coding in the visual system. Nevertheless, we don't understand yet the way in which some of the simplest perceptual properties of sounds are coded in neuronal activity. This poses serious difficulties for linking neuronal responses in the auditory system and music processing, since music operates on abstract representations of sounds. Paradoxically, although perceptual representations of sounds most probably occur high in auditory system or even beyond it, neuronal responses are strongly affected by the temporal organization of sound streams even in subcortical stations. Thus, to the extent that music is organized sound, it is the organization, rather than the sound, which is represented first in the auditory brain.

  18. From ear to hand: the role of the auditory-motor loop in pointing to an auditory source

    Science.gov (United States)

    Boyer, Eric O.; Babayan, Bénédicte M.; Bevilacqua, Frédéric; Noisternig, Markus; Warusfel, Olivier; Roby-Brami, Agnes; Hanneton, Sylvain; Viaud-Delmon, Isabelle

    2013-01-01

    Studies of the nature of the neural mechanisms involved in goal-directed movements tend to concentrate on the role of vision. We present here an attempt to address the mechanisms whereby an auditory input is transformed into a motor command. The spatial and temporal organization of hand movements were studied in normal human subjects as they pointed toward unseen auditory targets located in a horizontal plane in front of them. Positions and movements of the hand were measured by a six infrared camera tracking system. In one condition, we assessed the role of auditory information about target position in correcting the trajectory of the hand. To accomplish this, the duration of the target presentation was varied. In another condition, subjects received continuous auditory feedback of their hand movement while pointing to the auditory targets. Online auditory control of the direction of pointing movements was assessed by evaluating how subjects reacted to shifts in heard hand position. Localization errors were exacerbated by short duration of target presentation but not modified by auditory feedback of hand position. Long duration of target presentation gave rise to a higher level of accuracy and was accompanied by early automatic head orienting movements consistently related to target direction. These results highlight the efficiency of auditory feedback processing in online motor control and suggest that the auditory system takes advantages of dynamic changes of the acoustic cues due to changes in head orientation in order to process online motor control. How to design an informative acoustic feedback needs to be carefully studied to demonstrate that auditory feedback of the hand could assist the monitoring of movements directed at objects in auditory space. PMID:23626532

  19. From ear to hand: the role of the auditory-motor loop in pointing to an auditory source

    Directory of Open Access Journals (Sweden)

    Eric Olivier Boyer

    2013-04-01

    Full Text Available Studies of the nature of the neural mechanisms involved in goal-directed movements tend to concentrate on the role of vision. We present here an attempt to address the mechanisms whereby an auditory input is transformed into a motor command. The spatial and temporal organization of hand movements were studied in normal human subjects as they pointed towards unseen auditory targets located in a horizontal plane in front of them. Positions and movements of the hand were measured by a six infrared camera tracking system. In one condition, we assessed the role of auditory information about target position in correcting the trajectory of the hand. To accomplish this, the duration of the target presentation was varied. In another condition, subjects received continuous auditory feedback of their hand movement while pointing to the auditory targets. Online auditory control of the direction of pointing movements was assessed by evaluating how subjects reacted to shifts in heard hand position. Localization errors were exacerbated by short duration of target presentation but not modified by auditory feedback of hand position. Long duration of target presentation gave rise to a higher level of accuracy and was accompanied by early automatic head orienting movements consistently related to target direction. These results highlight the efficiency of auditory feedback processing in online motor control and suggest that the auditory system takes advantages of dynamic changes of the acoustic cues due to changes in head orientation in order to process online motor control. How to design an informative acoustic feedback needs to be carefully studied to demonstrate that auditory feedback of the hand could assist the monitoring of movements directed at objects in auditory space.

  20. Coding of melodic gestalt in human auditory cortex.

    Science.gov (United States)

    Schindler, Andreas; Herdener, Marcus; Bartels, Andreas

    2013-12-01

    The perception of a melody is invariant to the absolute properties of its constituting notes, but depends on the relation between them-the melody's relative pitch profile. In fact, a melody's "Gestalt" is recognized regardless of the instrument or key used to play it. Pitch processing in general is assumed to occur at the level of the auditory cortex. However, it is unknown whether early auditory regions are able to encode pitch sequences integrated over time (i.e., melodies) and whether the resulting representations are invariant to specific keys. Here, we presented participants different melodies composed of the same 4 harmonic pitches during functional magnetic resonance imaging recordings. Additionally, we played the same melodies transposed in different keys and on different instruments. We found that melodies were invariantly represented by their blood oxygen level-dependent activation patterns in primary and secondary auditory cortices across instruments, and also across keys. Our findings extend common hierarchical models of auditory processing by showing that melodies are encoded independent of absolute pitch and based on their relative pitch profile as early as the primary auditory cortex.

  1. Role of the auditory system in speech production.

    Science.gov (United States)

    Guenther, Frank H; Hickok, Gregory

    2015-01-01

    This chapter reviews evidence regarding the role of auditory perception in shaping speech output. Evidence indicates that speech movements are planned to follow auditory trajectories. This in turn is followed by a description of the Directions Into Velocities of Articulators (DIVA) model, which provides a detailed account of the role of auditory feedback in speech motor development and control. A brief description of the higher-order brain areas involved in speech sequencing (including the pre-supplementary motor area and inferior frontal sulcus) is then provided, followed by a description of the Hierarchical State Feedback Control (HSFC) model, which posits internal error detection and correction processes that can detect and correct speech production errors prior to articulation. The chapter closes with a treatment of promising future directions of research into auditory-motor interactions in speech, including the use of intracranial recording techniques such as electrocorticography in humans, the investigation of the potential roles of various large-scale brain rhythms in speech perception and production, and the development of brain-computer interfaces that use auditory feedback to allow profoundly paralyzed users to learn to produce speech using a speech synthesizer.

  2. Auditory and Visual Sensations

    CERN Document Server

    Ando, Yoichi

    2010-01-01

    Professor Yoichi Ando, acoustic architectural designer of the Kirishima International Concert Hall in Japan, presents a comprehensive rational-scientific approach to designing performance spaces. His theory is based on systematic psychoacoustical observations of spatial hearing and listener preferences, whose neuronal correlates are observed in the neurophysiology of the human brain. A correlation-based model of neuronal signal processing in the central auditory system is proposed in which temporal sensations (pitch, timbre, loudness, duration) are represented by an internal autocorrelation representation, and spatial sensations (sound location, size, diffuseness related to envelopment) are represented by an internal interaural crosscorrelation function. Together these two internal central auditory representations account for the basic auditory qualities that are relevant for listening to music and speech in indoor performance spaces. Observed psychological and neurophysiological commonalities between auditor...

  3. Using Hierarchical Folders and Tags for File Management

    Science.gov (United States)

    Ma, Shanshan

    2010-01-01

    Hierarchical folders have been widely used for managing digital files. A well constructed hierarchical structure can keep files organized. A parent folder can have several subfolders and one subfolder can only reside in one parent folder. Files are stored in folders or subfolders. Files can be found by traversing a given path, going through…

  4. Robust central pattern generators for embodied hierarchical reinforcement learning

    NARCIS (Netherlands)

    Snel, M.; Whiteson, S.; Kuniyoshi, Y.

    2011-01-01

    Hierarchical organization of behavior and learning is widespread in animals and robots, among others to facilitate dealing with multiple tasks. In hierarchical reinforcement learning, agents usually have to learn to recombine or modulate low-level behaviors when facing a new task, which costs time t

  5. Functional properties of human auditory cortical fields

    Directory of Open Access Journals (Sweden)

    David L Woods

    2010-12-01

    Full Text Available While auditory cortex in non-human primates has been subdivided into multiple functionally-specialized auditory cortical fields (ACFs, the boundaries and functional specialization of human ACFs have not been defined. In the current study, we evaluated whether a widely accepted primate model of auditory cortex could explain regional tuning properties of fMRI activations on the cortical surface to attended and nonattended tones of different frequency, location, and intensity. The limits of auditory cortex were defined by voxels that showed significant activations to nonattended sounds. Three centrally-located fields with mirror-symmetric tonotopic organization were identified and assigned to the three core fields of the primate model while surrounding activations were assigned to belt fields following procedures similar to those used in macaque fMRI studies. The functional properties of core, medial belt, and lateral belt field groups were then analyzed. Field groups were distinguished by tonotopic organization, frequency selectivity, intensity sensitivity, contralaterality, binaural enhancement, attentional modulation, and hemispheric asymmetry. In general, core fields showed greater sensitivity to sound properties than did belt fields, while belt fields showed greater attentional modulation than core fields. Significant distinctions in intensity sensitivity and contralaterality were seen between adjacent core fields A1 and R, while multiple differences in tuning properties were evident at boundaries between adjacent core and belt fields. The reliable differences in functional properties between fields and field groups suggest that the basic primate pattern of auditory cortex organization is preserved in humans. A comparison of the sizes of functionally-defined ACFs in humans and macaques reveals a significant relative expansion in human lateral belt fields implicated in the processing of speech.

  6. Hierarchical representations of the five-factor model of personality in predicting job performance: integrating three organizing frameworks with two theoretical perspectives.

    Science.gov (United States)

    Judge, Timothy A; Rodell, Jessica B; Klinger, Ryan L; Simon, Lauren S; Crawford, Eean R

    2013-11-01

    Integrating 2 theoretical perspectives on predictor-criterion relationships, the present study developed and tested a hierarchical framework in which each five-factor model (FFM) personality trait comprises 2 DeYoung, Quilty, and Peterson (2007) facets, which in turn comprise 6 Costa and McCrae (1992) NEO facets. Both theoretical perspectives-the bandwidth-fidelity dilemma and construct correspondence-suggest that lower order traits would better predict facets of job performance (task performance and contextual performance). They differ, however, as to the relative merits of broad and narrow traits in predicting a broad criterion (overall job performance). We first meta-analyzed the relationship of the 30 NEO facets to overall job performance and its facets. Overall, 1,176 correlations from 410 independent samples (combined N = 406,029) were coded and meta-analyzed. We then formed the 10 DeYoung et al. facets from the NEO facets, and 5 broad traits from those facets. Overall, results provided support for the 6-2-1 framework in general and the importance of the NEO facets in particular. (c) 2013 APA, all rights reserved.

  7. Sharing the proceeds from a hierarchical venture

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Moreno-Ternero, Juan D.; Tvede, Mich;

    2017-01-01

    We consider the problem of distributing the proceeds generated from a joint venture in which the participating agents are hierarchically organized. We introduce and characterize a family of allocation rules where revenue ‘bubbles up’ in the hierarchy. The family is flexible enough to accommodate...

  8. Human Auditory Processing: Insights from Cortical Event-related Potentials

    Directory of Open Access Journals (Sweden)

    Alexandra P. Key

    2016-04-01

    Full Text Available Human communication and language skills rely heavily on the ability to detect and process auditory inputs. This paper reviews possible applications of the event-related potential (ERP technique to the study of cortical mechanisms supporting human auditory processing, including speech stimuli. Following a brief introduction to the ERP methodology, the remaining sections focus on demonstrating how ERPs can be used in humans to address research questions related to cortical organization, maturation and plasticity, as well as the effects of sensory deprivation, and multisensory interactions. The review is intended to serve as a primer for researchers interested in using ERPs for the study of the human auditory system.

  9. Parallel hierarchical radiosity rendering

    Energy Technology Data Exchange (ETDEWEB)

    Carter, M.

    1993-07-01

    In this dissertation, the step-by-step development of a scalable parallel hierarchical radiosity renderer is documented. First, a new look is taken at the traditional radiosity equation, and a new form is presented in which the matrix of linear system coefficients is transformed into a symmetric matrix, thereby simplifying the problem and enabling a new solution technique to be applied. Next, the state-of-the-art hierarchical radiosity methods are examined for their suitability to parallel implementation, and scalability. Significant enhancements are also discovered which both improve their theoretical foundations and improve the images they generate. The resultant hierarchical radiosity algorithm is then examined for sources of parallelism, and for an architectural mapping. Several architectural mappings are discussed. A few key algorithmic changes are suggested during the process of making the algorithm parallel. Next, the performance, efficiency, and scalability of the algorithm are analyzed. The dissertation closes with a discussion of several ideas which have the potential to further enhance the hierarchical radiosity method, or provide an entirely new forum for the application of hierarchical methods.

  10. Auditory excitation patterns : the significance of the pulsation threshold method for the measurement of auditory nonlinearity

    NARCIS (Netherlands)

    H. Verschuure (Hans)

    1978-01-01

    textabstractThe auditory system is the toto[ of organs that translates an acoustical signal into the perception of a sound. An acoustic signal is a vibration. It is decribed by physical parameters. The perception of sound is the awareness of a signal being present and the attribution of certain qual

  11. Auditory evacuation beacons

    NARCIS (Netherlands)

    Wijngaarden, S.J. van; Bronkhorst, A.W.; Boer, L.C.

    2005-01-01

    Auditory evacuation beacons can be used to guide people to safe exits, even when vision is totally obscured by smoke. Conventional beacons make use of modulated noise signals. Controlled evacuation experiments show that such signals require explicit instructions and are often misunderstood. A new si

  12. Virtual Auditory Displays

    Science.gov (United States)

    2000-01-01

    timbre , intensity, distance, room modeling, radio communication Virtual Environments Handbook Chapter 4 Virtual Auditory Displays Russell D... musical note “A” as a pure sinusoid, there will be 440 condensations and rarefactions per second. The distance between two adjacent condensations or...and complexity are pitch, loudness, and timbre respectively. This distinction between physical and perceptual measures of sound properties is an

  13. Neutrosophic Hierarchical Clustering Algoritms

    Directory of Open Access Journals (Sweden)

    Rıdvan Şahin

    2014-03-01

    Full Text Available Interval neutrosophic set (INS is a generalization of interval valued intuitionistic fuzzy set (IVIFS, whose the membership and non-membership values of elements consist of fuzzy range, while single valued neutrosophic set (SVNS is regarded as extension of intuitionistic fuzzy set (IFS. In this paper, we extend the hierarchical clustering techniques proposed for IFSs and IVIFSs to SVNSs and INSs respectively. Based on the traditional hierarchical clustering procedure, the single valued neutrosophic aggregation operator, and the basic distance measures between SVNSs, we define a single valued neutrosophic hierarchical clustering algorithm for clustering SVNSs. Then we extend the algorithm to classify an interval neutrosophic data. Finally, we present some numerical examples in order to show the effectiveness and availability of the developed clustering algorithms.

  14. The neglected neglect: auditory neglect.

    Science.gov (United States)

    Gokhale, Sankalp; Lahoti, Sourabh; Caplan, Louis R

    2013-08-01

    Whereas visual and somatosensory forms of neglect are commonly recognized by clinicians, auditory neglect is often not assessed and therefore neglected. The auditory cortical processing system can be functionally classified into 2 distinct pathways. These 2 distinct functional pathways deal with recognition of sound ("what" pathway) and the directional attributes of the sound ("where" pathway). Lesions of higher auditory pathways produce distinct clinical features. Clinical bedside evaluation of auditory neglect is often difficult because of coexisting neurological deficits and the binaural nature of auditory inputs. In addition, auditory neglect and auditory extinction may show varying degrees of overlap, which makes the assessment even harder. Shielding one ear from the other as well as separating the ear from space is therefore critical for accurate assessment of auditory neglect. This can be achieved by use of specialized auditory tests (dichotic tasks and sound localization tests) for accurate interpretation of deficits. Herein, we have reviewed auditory neglect with an emphasis on the functional anatomy, clinical evaluation, and basic principles of specialized auditory tests.

  15. Hierarchical social networks and information flow

    Science.gov (United States)

    López, Luis; F. F. Mendes, Jose; Sanjuán, Miguel A. F.

    2002-12-01

    Using a simple model for the information flow on social networks, we show that the traditional hierarchical topologies frequently used by companies and organizations, are poorly designed in terms of efficiency. Moreover, we prove that this type of structures are the result of the individual aim of monopolizing as much information as possible within the network. As the information is an appropriate measurement of centrality, we conclude that this kind of topology is so attractive for leaders, because the global influence each actor has within the network is completely determined by the hierarchical level occupied.

  16. Hierarchic Models of Turbulence, Superfluidity and Superconductivity

    CERN Document Server

    Kaivarainen, A

    2000-01-01

    New models of Turbulence, Superfluidity and Superconductivity, based on new Hierarchic theory, general for liquids and solids (physics/0102086), have been proposed. CONTENTS: 1 Turbulence. General description; 2 Mesoscopic mechanism of turbulence; 3 Superfluidity. General description; 4 Mesoscopic scenario of fluidity; 5 Superfluidity as a hierarchic self-organization process; 6 Superfluidity in 3He; 7 Superconductivity: General properties of metals and semiconductors; Plasma oscillations; Cyclotron resonance; Electroconductivity; 8. Microscopic theory of superconductivity (BCS); 9. Mesoscopic scenario of superconductivity: Interpretation of experimental data in the framework of mesoscopic model of superconductivity.

  17. Integration and segregation in auditory scene analysis

    Science.gov (United States)

    Sussman, Elyse S.

    2005-03-01

    Assessment of the neural correlates of auditory scene analysis, using an index of sound change detection that does not require the listener to attend to the sounds [a component of event-related brain potentials called the mismatch negativity (MMN)], has previously demonstrated that segregation processes can occur without attention focused on the sounds and that within-stream contextual factors influence how sound elements are integrated and represented in auditory memory. The current study investigated the relationship between the segregation and integration processes when they were called upon to function together. The pattern of MMN results showed that the integration of sound elements within a sound stream occurred after the segregation of sounds into independent streams and, further, that the individual streams were subject to contextual effects. These results are consistent with a view of auditory processing that suggests that the auditory scene is rapidly organized into distinct streams and the integration of sequential elements to perceptual units takes place on the already formed streams. This would allow for the flexibility required to identify changing within-stream sound patterns, needed to appreciate music or comprehend speech..

  18. Towards a sustainable manufacture of hierarchical zeolites.

    Science.gov (United States)

    Verboekend, Danny; Pérez-Ramírez, Javier

    2014-03-01

    Hierarchical zeolites have been established as a superior type of aluminosilicate catalysts compared to their conventional (purely microporous) counterparts. An impressive array of bottom-up and top-down approaches has been developed during the last decade to design and subsequently exploit these exciting materials catalytically. However, the sustainability of the developed synthetic methods has rarely been addressed. This paper highlights important criteria to ensure the ecological and economic viability of the manufacture of hierarchical zeolites. Moreover, by using base leaching as a promising case study, we verify a variety of approaches to increase reactor productivity, recycle waste streams, prevent the combustion of organic compounds, and minimize separation efforts. By reducing their synthetic footprint, hierarchical zeolites are positioned as an integral part of sustainable chemistry. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Anatomy and Physiology of the Auditory Tracts

    Directory of Open Access Journals (Sweden)

    Mohammad hosein Hekmat Ara

    1999-03-01

    Full Text Available Hearing is one of the excel sense of human being. Sound waves travel through the medium of air and enter the ear canal and then hit the tympanic membrane. Middle ear transfer almost 60-80% of this mechanical energy to the inner ear by means of “impedance matching”. Then, the sound energy changes to traveling wave and is transferred based on its specific frequency and stimulates organ of corti. Receptors in this organ and their synapses transform mechanical waves to the neural waves and transfer them to the brain. The central nervous system tract of conducting the auditory signals in the auditory cortex will be explained here briefly.

  20. PLASTICITY IN THE ADULT CENTRAL AUDITORY SYSTEM.

    Science.gov (United States)

    Irvine, Dexter R F; Fallon, James B; Kamke, Marc R

    2006-04-01

    The central auditory system retains into adulthood a remarkable capacity for plastic changes in the response characteristics of single neurons and the functional organization of groups of neurons. The most dramatic examples of this plasticity are provided by changes in frequency selectivity and organization as a consequence of either partial hearing loss or procedures that alter the significance of particular frequencies for the organism. Changes in temporal resolution are also seen as a consequence of altered experience. These forms of plasticity are likely to contribute to the improvements exhibited by cochlear implant users in the post-implantation period.

  1. PLASTICITY IN THE ADULT CENTRAL AUDITORY SYSTEM

    Science.gov (United States)

    Irvine, Dexter R. F.; Fallon, James B.; Kamke, Marc R.

    2007-01-01

    The central auditory system retains into adulthood a remarkable capacity for plastic changes in the response characteristics of single neurons and the functional organization of groups of neurons. The most dramatic examples of this plasticity are provided by changes in frequency selectivity and organization as a consequence of either partial hearing loss or procedures that alter the significance of particular frequencies for the organism. Changes in temporal resolution are also seen as a consequence of altered experience. These forms of plasticity are likely to contribute to the improvements exhibited by cochlear implant users in the post-implantation period. PMID:17572797

  2. Hierarchical Porous Structures

    Energy Technology Data Exchange (ETDEWEB)

    Grote, Christopher John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-07

    Materials Design is often at the forefront of technological innovation. While there has always been a push to generate increasingly low density materials, such as aero or hydrogels, more recently the idea of bicontinuous structures has gone more into play. This review will cover some of the methods and applications for generating both porous, and hierarchically porous structures.

  3. [The concept of the organ, as a hierarchal unit of human body, and its place in teaching histology at the medical university and medical college].

    Science.gov (United States)

    Miadelets, O D; Miadelets, N Ia; Miadelets, V O

    2011-01-01

    This paper deals with the methodological aspects of teaching histology at the medical university and medical college. The authors raise the issue of the necessity of teaching of the topic "Introduction to Special Histology" and the inclusion of the appropriate chapter into the textbooks. This is important for the students, as the formation of the general concepts of organ structure and function, components, and classification will aid in the further study of specific organs during the course of Special Histology. The authors describe their own experience in teaching of the section, dedicated to the general regularities of organ structure, present some definitions and classifications that are used by them for a number of years.

  4. Animal models for auditory streaming.

    Science.gov (United States)

    Itatani, Naoya; Klump, Georg M

    2017-02-19

    Sounds in the natural environment need to be assigned to acoustic sources to evaluate complex auditory scenes. Separating sources will affect the analysis of auditory features of sounds. As the benefits of assigning sounds to specific sources accrue to all species communicating acoustically, the ability for auditory scene analysis is widespread among different animals. Animal studies allow for a deeper insight into the neuronal mechanisms underlying auditory scene analysis. Here, we will review the paradigms applied in the study of auditory scene analysis and streaming of sequential sounds in animal models. We will compare the psychophysical results from the animal studies to the evidence obtained in human psychophysics of auditory streaming, i.e. in a task commonly used for measuring the capability for auditory scene analysis. Furthermore, the neuronal correlates of auditory streaming will be reviewed in different animal models and the observations of the neurons' response measures will be related to perception. The across-species comparison will reveal whether similar demands in the analysis of acoustic scenes have resulted in similar perceptual and neuronal processing mechanisms in the wide range of species being capable of auditory scene analysis.This article is part of the themed issue 'Auditory and visual scene analysis'.

  5. 应用生长、分级的自组织映射模型进行意识任务分类%GROWING HIERARCHICAL SELF-ORGANIZING MAP MODELS FOR MENTAL TASK CLASSIFICATION

    Institute of Scientific and Technical Information of China (English)

    刘海龙; 王珏; 郑崇勋

    2005-01-01

    提出一种使用生长、分级的自组织映射(growing hierarchical self-organizing map,GHSOM)模型进行基于EEG信号的意识任务分类来实现脑机接口技术的方法.GHSOM模型是自组织映射(self-organizing map,SOM)的一种变体,由多层的SOM组成,具有一定的分级结构,能够表达数据中不同层次的信息.同时研究了使用平均量化误差(mean quantization error,mqe)和量化误差(quantization error,qe)两种方法实现的GHSOM模型对意识任务分类的作用.结果表明,GHSOM模型对于意识任务的可分性能够提供可视化的信息,并且发现使用量化误差方法实现的GHSOM模型提供较多的数据信息和较高的分类精度.使用GHSOM模型进行了5类意识任务的分类,平均分类精度可达80%.

  6. Sensitivity improvement of a sandwich-type ELISA immunosensor for the detection of different prostate-specific antigen isoforms in human serum using electrochemical impedance spectroscopy and an ordered and hierarchically organized interfacial supramolecular architecture.

    Science.gov (United States)

    Gutiérrez-Zúñiga, Gabriela Guadalupe; Hernández-López, José Luis

    2016-01-01

    A gold millielectrode (GME) functionalized with a mixed (16-MHA + EG3SH) self-assembled monolayer (SAM) was used to fabricate an indirect enzyme-linked immunosorbent assay (ELISA) immunosensor for the sensitive detection of prostate-specific antigen (PSA), a prostate cancer (PCa) biomarker, in human serum samples. To address and minimize the issue of non-specific protein adsorption, an organic matrix (amine-PEG3-biotin/avidin) was assembled on the previously functionalized electrode surface to build up an ordered and hierarchically organized interfacial supramolecular architecture: Au/16-MHA/EG3SH/amine-PEG3-biotin/avidin. The electrode was then exposed to serum samples at different concentrations of a sandwich-type immunocomplex molecule ((Btn)Ab-AgPSA-(HRP)Ab), and its interfacial properties were characterized using electrochemical impedance spectroscopy (EIS). Calibration curves for polarization resistance (RP) and capacitance (1/C) vs. total and free PSA concentrations were obtained and their analytical quality parameters were determined. This approach was compared with results obtained from a commercially available ELISA immunosensor. The results obtained in this work showed that the proposed immunosensor can be successfully applied to analyze serum samples of patients representative of the Mexican population.

  7. Tonotopic and field-specific representation of long-lasting sustained activity in rat auditory cortex

    Directory of Open Access Journals (Sweden)

    Tomoyo Isoguchi Shiramatsu

    2016-08-01

    performance of the SLR deteriorated when the test frequencies were close, supporting the hypothesis that the sustained activities were organized in a tonotopic manner. Finally, unlike transient activities, sustained activities were more informative in the belt than in the core region, indicating that higher-order auditory areas predominate over lower-order areas during sustained activities. Taken together, our results indicate that the auditory cortex processes sound information tonotopically and in a hierarchical manner.

  8. Cortical connections of auditory cortex in marmoset monkeys: lateral belt and parabelt regions.

    Science.gov (United States)

    de la Mothe, Lisa A; Blumell, Suzanne; Kajikawa, Yoshinao; Hackett, Troy A

    2012-05-01

    The current working model of primate auditory cortex is constructed from a number of studies of both new and old world monkeys. It includes three levels of processing. A primary level, the core region, is surrounded both medially and laterally by a secondary belt region. A third level of processing, the parabelt region, is located lateral to the belt. The marmoset monkey (Callithrix jacchus jacchus) has become an important model system to study auditory processing, but its anatomical organization has not been fully established. In previous studies, we focused on the architecture and connections of the core and medial belt areas (de la Mothe et al., 2006a, J Comp Neurol 496:27-71; de la Mothe et al., 2006b, J Comp Neurol 496:72-96). In this study, the corticocortical connections of the lateral belt and parabelt were examined in the marmoset. Tracers were injected into both rostral and caudal portions of the lateral belt and parabelt. Both regions revealed topographic connections along the rostrocaudal axis, where caudal areas of injection had stronger connections with caudal areas, and rostral areas of injection with rostral areas. The lateral belt had strong connections with the core, belt, and parabelt, whereas the parabelt had strong connections with the belt but not the core. Label in the core from injections in the parabelt was significantly reduced or absent, consistent with the idea that the parabelt relies mainly on the belt for its cortical input. In addition, the present and previous studies indicate hierarchical principles of anatomical organization in the marmoset that are consistent with those observed in other primates.

  9. Profile of auditory information-processing deficits in schizophrenia.

    Science.gov (United States)

    Turetsky, Bruce I; Bilker, Warren B; Siegel, Steven J; Kohler, Christian G; Gur, Raquel E

    2009-01-30

    Schizophrenia patients exhibit abnormalities in several different auditory event-related potential (ERP) measures. It is unclear how these abnormalities relate to each other, since multiple measures are rarely acquired from the same sample. This study addressed two related questions: 1) Are specific auditory ERP measures differentially impaired in schizophrenia? 2) Do abnormalities co-aggregate within the same patients? Nine auditory ERP measures were acquired in a single testing session from 23 schizophrenia patients and 22 healthy subjects. Hierarchical oblique factor analysis revealed that these measures aggregated into four factors, with each loading primarily on a single factor. Patient deficits were observed for two independent factors: N100/mismatch negativity (MMN) and P3a/P3b. N100/MMN abnormalities were associated with symptoms of alogia and formal thought disorder. P3a/P3b abnormalities were associated with avolition, attentional disturbances and delusions. We conclude that deficits in different ERP measures of early sensory processing at the level of the auditory cortex co-occur in patients. These likely represent a single differential deficit indexing the physiological abnormality underlying impaired language and verbal processing. This is relatively independent of a higher cortical deficit that mediates cognitive stimulus evaluation and underlies deficits in motivation, attention and reality testing. Such multidimensional profiling of ERP abnormalities may help to clarify the clinical and genetic heterogeneity of schizophrenia.

  10. Metabolic emergent auditory effects by means of physical particle modeling : the example of musical sand

    OpenAIRE

    Luciani, Annie; Castagné, Nicolas; Tixier, Nicolas

    2003-01-01

    International audience; In the context of Computer Music, physical modeling is usually dedicated to the modeling of sound sources or physical instruments. This paper presents an innovative use of physical modeling in order to model and synthesize complex auditory effects such as collective acoustic phenomena producing metabolic emergent auditory organizations. As a case study, we chose the "dune effect", which in open nature leads both to visual and auditory effects. The article introduces tw...

  11. Collaborative Hierarchical Sparse Modeling

    CERN Document Server

    Sprechmann, Pablo; Sapiro, Guillermo; Eldar, Yonina C

    2010-01-01

    Sparse modeling is a powerful framework for data analysis and processing. Traditionally, encoding in this framework is done by solving an l_1-regularized linear regression problem, usually called Lasso. In this work we first combine the sparsity-inducing property of the Lasso model, at the individual feature level, with the block-sparsity property of the group Lasso model, where sparse groups of features are jointly encoded, obtaining a sparsity pattern hierarchically structured. This results in the hierarchical Lasso, which shows important practical modeling advantages. We then extend this approach to the collaborative case, where a set of simultaneously coded signals share the same sparsity pattern at the higher (group) level but not necessarily at the lower one. Signals then share the same active groups, or classes, but not necessarily the same active set. This is very well suited for applications such as source separation. An efficient optimization procedure, which guarantees convergence to the global opt...

  12. Hierarchical manifold learning.

    Science.gov (United States)

    Bhatia, Kanwal K; Rao, Anil; Price, Anthony N; Wolz, Robin; Hajnal, Jo; Rueckert, Daniel

    2012-01-01

    We present a novel method of hierarchical manifold learning which aims to automatically discover regional variations within images. This involves constructing manifolds in a hierarchy of image patches of increasing granularity, while ensuring consistency between hierarchy levels. We demonstrate its utility in two very different settings: (1) to learn the regional correlations in motion within a sequence of time-resolved images of the thoracic cavity; (2) to find discriminative regions of 3D brain images in the classification of neurodegenerative disease,

  13. Hierarchically Structured Electrospun Fibers

    Directory of Open Access Journals (Sweden)

    Nicole E. Zander

    2013-01-01

    Full Text Available Traditional electrospun nanofibers have a myriad of applications ranging from scaffolds for tissue engineering to components of biosensors and energy harvesting devices. The generally smooth one-dimensional structure of the fibers has stood as a limitation to several interesting novel applications. Control of fiber diameter, porosity and collector geometry will be briefly discussed, as will more traditional methods for controlling fiber morphology and fiber mat architecture. The remainder of the review will focus on new techniques to prepare hierarchically structured fibers. Fibers with hierarchical primary structures—including helical, buckled, and beads-on-a-string fibers, as well as fibers with secondary structures, such as nanopores, nanopillars, nanorods, and internally structured fibers and their applications—will be discussed. These new materials with helical/buckled morphology are expected to possess unique optical and mechanical properties with possible applications for negative refractive index materials, highly stretchable/high-tensile-strength materials, and components in microelectromechanical devices. Core-shell type fibers enable a much wider variety of materials to be electrospun and are expected to be widely applied in the sensing, drug delivery/controlled release fields, and in the encapsulation of live cells for biological applications. Materials with a hierarchical secondary structure are expected to provide new superhydrophobic and self-cleaning materials.

  14. Hierarchical video summarization

    Science.gov (United States)

    Ratakonda, Krishna; Sezan, M. Ibrahim; Crinon, Regis J.

    1998-12-01

    We address the problem of key-frame summarization of vide in the absence of any a priori information about its content. This is a common problem that is encountered in home videos. We propose a hierarchical key-frame summarization algorithm where a coarse-to-fine key-frame summary is generated. A hierarchical key-frame summary facilitates multi-level browsing where the user can quickly discover the content of the video by accessing its coarsest but most compact summary and then view a desired segment of the video with increasingly more detail. At the finest level, the summary is generated on the basis of color features of video frames, using an extension of a recently proposed key-frame extraction algorithm. The finest level key-frames are recursively clustered using a novel pairwise K-means clustering approach with temporal consecutiveness constraint. We also address summarization of MPEG-2 compressed video without fully decoding the bitstream. We also propose efficient mechanisms that facilitate decoding the video when the hierarchical summary is utilized in browsing and playback of video segments starting at selected key-frames.

  15. Behind the Scenes of Auditory Perception

    OpenAIRE

    Shamma, Shihab A.; Micheyl, Christophe

    2010-01-01

    Auditory scenes” often contain contributions from multiple acoustic sources. These are usually heard as separate auditory “streams”, which can be selectively followed over time. How and where these auditory streams are formed in the auditory system is one of the most fascinating questions facing auditory scientists today. Findings published within the last two years indicate that both cortical and sub-cortical processes contribute to the formation of auditory streams, and they raise importan...

  16. Auditory and non-auditory effects of noise on health

    NARCIS (Netherlands)

    Basner, M.; Babisch, W.; Davis, A.; Brink, M.; Clark, C.; Janssen, S.A.; Stansfeld, S.

    2013-01-01

    Noise is pervasive in everyday life and can cause both auditory and non-auditory health eff ects. Noise-induced hearing loss remains highly prevalent in occupational settings, and is increasingly caused by social noise exposure (eg, through personal music players). Our understanding of molecular mec

  17. Auditory and non-auditory effects of noise on health

    NARCIS (Netherlands)

    Basner, M.; Babisch, W.; Davis, A.; Brink, M.; Clark, C.; Janssen, S.A.; Stansfeld, S.

    2013-01-01

    Noise is pervasive in everyday life and can cause both auditory and non-auditory health eff ects. Noise-induced hearing loss remains highly prevalent in occupational settings, and is increasingly caused by social noise exposure (eg, through personal music players). Our understanding of molecular

  18. Spiking neurons in a hierarchical self-organizing map model can learn to develop spatial and temporal properties of entorhinal grid cells and hippocampal place cells.

    Directory of Open Access Journals (Sweden)

    Praveen K Pilly

    Full Text Available Medial entorhinal grid cells and hippocampal place cells provide neural correlates of spatial representation in the brain. A place cell typically fires whenever an animal is present in one or more spatial regions, or places, of an environment. A grid cell typically fires in multiple spatial regions that form a regular hexagonal grid structure extending throughout the environment. Different grid and place cells prefer spatially offset regions, with their firing fields increasing in size along the dorsoventral axes of the medial entorhinal cortex and hippocampus. The spacing between neighboring fields for a grid cell also increases along the dorsoventral axis. This article presents a neural model whose spiking neurons operate in a hierarchy of self-organizing maps, each obeying the same laws. This spiking GridPlaceMap model simulates how grid cells and place cells may develop. It responds to realistic rat navigational trajectories by learning grid cells with hexagonal grid firing fields of multiple spatial scales and place cells with one or more firing fields that match neurophysiological data about these cells and their development in juvenile rats. The place cells represent much larger spaces than the grid cells, which enable them to support navigational behaviors. Both self-organizing maps amplify and learn to categorize the most frequent and energetic co-occurrences of their inputs. The current results build upon a previous rate-based model of grid and place cell learning, and thus illustrate a general method for converting rate-based adaptive neural models, without the loss of any of their analog properties, into models whose cells obey spiking dynamics. New properties of the spiking GridPlaceMap model include the appearance of theta band modulation. The spiking model also opens a path for implementation in brain-emulating nanochips comprised of networks of noisy spiking neurons with multiple-level adaptive weights for controlling autonomous

  19. Clinical Observation on Treatment of Auditory Hallucinosis by Electroacupuncture--A Report of 30 Cases

    Institute of Scientific and Technical Information of China (English)

    Lin Hong; Li Cheng

    2005-01-01

    @@ Auditory hallucinosis, a kind of hallucinations in sensory disturbance, is very common in psychopathic clinic. Patients with this disorder could hear sounds of different variety or nature in the absence of any appropriate external stimulus. It is especially true in patients with schizophrenia, organic psychonosema,and alcoholic psychonosema. At present, the neuroleptic agents are often used to relieve auditory hallucinosis during treatment of the mental disease,and there is not a therapy that is effective in treating auditory hallucinosis. With electro-acupuncture, the authors have treated 30 cases of auditory hallucinosis with satisfactory results. A report follows.

  20. Word Recognition in Auditory Cortex

    Science.gov (United States)

    DeWitt, Iain D. J.

    2013-01-01

    Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

  1. Partial Epilepsy with Auditory Features

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2004-07-01

    Full Text Available The clinical characteristics of 53 sporadic (S cases of idiopathic partial epilepsy with auditory features (IPEAF were analyzed and compared to previously reported familial (F cases of autosomal dominant partial epilepsy with auditory features (ADPEAF in a study at the University of Bologna, Italy.

  2. Hierarchical Cobalt Hydroxide and B/N Co-Doped Graphene Nanohybrids Derived from Metal-Organic Frameworks for High Energy Density Asymmetric Supercapacitors

    Science.gov (United States)

    Tabassum, Hassina; Mahmood, Asif; Wang, Qingfei; Xia, Wei; Liang, Zibin; Qiu, Bin; Zhao, Ruo; Zou, Ruqiang

    2017-02-01

    To cater for the demands of electrochemical energy storage system, the development of cost effective, durable and highly efficient electrode materials is desired. Here, a novel electrode material based on redox active β-Co(OH)2 and B, N co-doped graphene nanohybrid is presented for electrochemical supercapacitor by employing a facile metal-organic frameworks (MOFs) route through pyrolysis and hydrothermal treatment. The Co(OH)2 could be firmly stabilized by dual protection of N-doped carbon polyhedron (CP) and B/N co-doped graphene (BCN) nanosheets. Interestingly, the porous carbon and BCN nanosheets greatly improve the charge storage, wettability, and redox activity of electrodes. Thus the hybrid delivers specific capacitance of 1263 F g‑1 at a current density of 1A g‑1 with 90% capacitance retention over 5000 cycles. Furthermore, the new aqueous asymmetric supercapacitor (ASC) was also designed by using Co(OH)2@CP@BCN nanohybrid and BCN nanosheets as positive and negative electrodes respectively, which leads to high energy density of 20.25 Whkg‑1. This device also exhibits excellent rate capability with energy density of 15.55 Whkg‑1 at power density of 9331 Wkg‑1 coupled long termed stability up to 6000 cycles.

  3. Hierarchical Cobalt Hydroxide and B/N Co-Doped Graphene Nanohybrids Derived from Metal-Organic Frameworks for High Energy Density Asymmetric Supercapacitors

    Science.gov (United States)

    Tabassum, Hassina; Mahmood, Asif; Wang, Qingfei; Xia, Wei; Liang, Zibin; Qiu, Bin; zhao, Ruo; Zou, Ruqiang

    2017-01-01

    To cater for the demands of electrochemical energy storage system, the development of cost effective, durable and highly efficient electrode materials is desired. Here, a novel electrode material based on redox active β-Co(OH)2 and B, N co-doped graphene nanohybrid is presented for electrochemical supercapacitor by employing a facile metal-organic frameworks (MOFs) route through pyrolysis and hydrothermal treatment. The Co(OH)2 could be firmly stabilized by dual protection of N-doped carbon polyhedron (CP) and B/N co-doped graphene (BCN) nanosheets. Interestingly, the porous carbon and BCN nanosheets greatly improve the charge storage, wettability, and redox activity of electrodes. Thus the hybrid delivers specific capacitance of 1263 F g−1 at a current density of 1A g−1 with 90% capacitance retention over 5000 cycles. Furthermore, the new aqueous asymmetric supercapacitor (ASC) was also designed by using Co(OH)2@CP@BCN nanohybrid and BCN nanosheets as positive and negative electrodes respectively, which leads to high energy density of 20.25 Whkg−1. This device also exhibits excellent rate capability with energy density of 15.55 Whkg−1 at power density of 9331 Wkg−1 coupled long termed stability up to 6000 cycles. PMID:28240224

  4. Modular, Hierarchical Learning By Artificial Neural Networks

    Science.gov (United States)

    Baldi, Pierre F.; Toomarian, Nikzad

    1996-01-01

    Modular and hierarchical approach to supervised learning by artificial neural networks leads to neural networks more structured than neural networks in which all neurons fully interconnected. These networks utilize general feedforward flow of information and sparse recurrent connections to achieve dynamical effects. The modular organization, sparsity of modular units and connections, and fact that learning is much more circumscribed are all attractive features for designing neural-network hardware. Learning streamlined by imitating some aspects of biological neural networks.

  5. Effects of tonotopicity, adaptation, modulation tuning, and temporal coherence in “primitive” auditory stream segregation

    DEFF Research Database (Denmark)

    Christiansen, Simon Krogholt; Jepsen, Morten Løve; Dau, Torsten

    2014-01-01

    The perceptual organization of two-tone sequences into auditory streams was investigated using a modeling framework consisting of an auditory pre-processing front end [Dau et al., J. Acoust. Soc. Am. 102, 2892–2905 (1997)] combined with a temporal coherence-analysis back end [Elhilali et al...

  6. Representation of lateralization and tonotopy in primary versus secondary human auditory cortex

    NARCIS (Netherlands)

    Langers, Dave R. M.; Backes, Walter H.; van Dijk, Pim

    2007-01-01

    Functional MRI was performed to investigate differences in the basic functional organization of the primary and secondary auditory cortex regarding preferred stimulus lateratization and frequency. A modified sparse acquisition scheme was used to spatially map the characteristics of the auditory cort

  7. Auditory and visual lexical neighborhoods in audiovisual speech perception.

    Science.gov (United States)

    Tye-Murray, Nancy; Sommers, Mitchell; Spehar, Brent

    2007-12-01

    Much evidence suggests that the mental lexicon is organized into auditory neighborhoods, with words that are phonologically similar belonging to the same neighborhood. In this investigation, we considered the existence of visual neighborhoods. When a receiver watches someone speak a word, a neighborhood of homophenes (ie, words that look alike on the face, such as pat and bat) is activated. The simultaneous activation of a word's auditory and visual neighborhoods may, in part, account for why individuals recognize speech better in an auditory-visual condition than what would be predicted by their performance in audition-only and vision-only conditions. A word test was administered to 3 groups of participants in audition-only, vision-only, and auditory-visual conditions, in the presence of 6-talker babble. Test words with sparse visual neighborhoods were recognized more accurately than words with dense neighborhoods in a vision-only condition. Densities of both the acoustic and visual neighborhoods as well as their intersection overlap were predictive of how well the test words were recognized in the auditory-visual condition. These results suggest that visual neighborhoods exist and that they affect auditory-visual speech perception. One implication is that in the presence of dual sensory impairment, the boundaries of both acoustic and visual neighborhoods may shift, adversely affecting speech recognition.

  8. The neural processing of hierarchical structure in music and speech at different timescales

    Directory of Open Access Journals (Sweden)

    Morwaread Mary Farbood

    2015-05-01

    Full Text Available Music, like speech, is a complex auditory signal that contains structures at multiple timescales, and as such a potentially powerful entry point into the question of how the brain integrates complex streams of information. Using an experimental design modeled after previous studies that used scrambled versions of a spoken story (Lerner, Honey, Silbert, & Hasson, 2011 and a silent movie (Hasson, Yang, Vallines, Heeger, & Rubin, 2008, we investigate whether listeners perceive hierarchical structure in music beyond short (~6 sec time windows and whether there is cortical overlap between music and language processing at multiple timescales. Experienced pianists were presented with an extended musical excerpt scrambled at multiple timescales––by measure, phrase, and section––while measuring brain activity with functional magnetic resonance imaging (fMRI. The reliability of evoked activity, as quantified by inter-subject correlation of the fMRI responses was measured. We found that response reliability depended systematically on musical structural coherence, revealing a topographically organized hierarchy of processing timescales. Early auditory areas (at the bottom of the hierarchy responded reliably in all conditions. For brain areas at the top of the hierarchy, the original (unscrambled excerpt evoked more reliable responses than any of the scrambled excerpts, indicating that these brain areas process long-timescale musical structures, on the order of minutes. The topography of processing timescales was analogous with that reported previously for speech, but the timescale gradients for music and speech overlapped with one another only partially, suggesting that temporally analogous structures––words/measures, sentences/musical phrases, paragraph/sections––are processed separately.

  9. The neural processing of hierarchical structure in music and speech at different timescales

    Science.gov (United States)

    Farbood, Morwaread M.; Heeger, David J.; Marcus, Gary; Hasson, Uri; Lerner, Yulia

    2015-01-01

    Music, like speech, is a complex auditory signal that contains structures at multiple timescales, and as such is a potentially powerful entry point into the question of how the brain integrates complex streams of information. Using an experimental design modeled after previous studies that used scrambled versions of a spoken story (Lerner et al., 2011) and a silent movie (Hasson et al., 2008), we investigate whether listeners perceive hierarchical structure in music beyond short (~6 s) time windows and whether there is cortical overlap between music and language processing at multiple timescales. Experienced pianists were presented with an extended musical excerpt scrambled at multiple timescales—by measure, phrase, and section—while measuring brain activity with functional magnetic resonance imaging (fMRI). The reliability of evoked activity, as quantified by inter-subject correlation of the fMRI responses, was measured. We found that response reliability depended systematically on musical structure coherence, revealing a topographically organized hierarchy of processing timescales. Early auditory areas (at the bottom of the hierarchy) responded reliably in all conditions. For brain areas at the top of the hierarchy, the original (unscrambled) excerpt evoked more reliable responses than any of the scrambled excerpts, indicating that these brain areas process long-timescale musical structures, on the order of minutes. The topography of processing timescales was analogous with that reported previously for speech, but the timescale gradients for music and speech overlapped with one another only partially, suggesting that temporally analogous structures—words/measures, sentences/musical phrases, paragraph/sections—are processed separately. PMID:26029037

  10. Context updates are hierarchical

    Directory of Open Access Journals (Sweden)

    Anton Karl Ingason

    2016-10-01

    Full Text Available This squib studies the order in which elements are added to the shared context of interlocutors in a conversation. It focuses on context updates within one hierarchical structure and argues that structurally higher elements are entered into the context before lower elements, even if the structurally higher elements are pronounced after the lower elements. The crucial data are drawn from a comparison of relative clauses in two head-initial languages, English and Icelandic, and two head-final languages, Korean and Japanese. The findings have consequences for any theory of a dynamic semantics.

  11. Auditory Cortex Characteristics in Schizophrenia: Associations With Auditory Hallucinations.

    Science.gov (United States)

    Mørch-Johnsen, Lynn; Nesvåg, Ragnar; Jørgensen, Kjetil N; Lange, Elisabeth H; Hartberg, Cecilie B; Haukvik, Unn K; Kompus, Kristiina; Westerhausen, René; Osnes, Kåre; Andreassen, Ole A; Melle, Ingrid; Hugdahl, Kenneth; Agartz, Ingrid

    2017-01-01

    Neuroimaging studies have demonstrated associations between smaller auditory cortex volume and auditory hallucinations (AH) in schizophrenia. Reduced cortical volume can result from a reduction of either cortical thickness or cortical surface area, which may reflect different neuropathology. We investigate for the first time how thickness and surface area of the auditory cortex relate to AH in a large sample of schizophrenia spectrum patients. Schizophrenia spectrum (n = 194) patients underwent magnetic resonance imaging. Mean cortical thickness and surface area in auditory cortex regions (Heschl's gyrus [HG], planum temporale [PT], and superior temporal gyrus [STG]) were compared between patients with (AH+, n = 145) and without (AH-, n = 49) a lifetime history of AH and 279 healthy controls. AH+ patients showed significantly thinner cortex in the left HG compared to AH- patients (d = 0.43, P = .0096). There were no significant differences between AH+ and AH- patients in cortical thickness in the PT or STG, or in auditory cortex surface area in any of the regions investigated. Group differences in cortical thickness in the left HG was not affected by duration of illness or current antipsychotic medication. AH in schizophrenia patients were related to thinner cortex, but not smaller surface area of the left HG, a region which includes the primary auditory cortex. The results support that structural abnormalities of the auditory cortex underlie AH in schizophrenia. © The Author 2016. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. MAP3K1 function is essential for cytoarchitecture of the mouse organ of Corti and survival of auditory hair cells

    Directory of Open Access Journals (Sweden)

    Rizwan Yousaf

    2015-12-01

    Full Text Available MAP3K1 is a serine/threonine kinase that is activated by a diverse set of stimuli and exerts its effect through various downstream effecter molecules, including JNK, ERK1/2 and p38. In humans, mutant alleles of MAP3K1 are associated with 46,XY sex reversal. Until recently, the only phenotype observed in Map3k1tm1Yxia mutant mice was open eyelids at birth. Here, we report that homozygous Map3k1tm1Yxia mice have early-onset profound hearing loss accompanied by the progressive degeneration of cochlear outer hair cells. In the mouse inner ear, MAP3K1 has punctate localization at the apical surface of the supporting cells in close proximity to basal bodies. Although the cytoarchitecture, neuronal wiring and synaptic junctions in the organ of Corti are grossly preserved, Map3k1tm1Yxia mutant mice have supernumerary functional outer hair cells (OHCs and Deiters' cells. Loss of MAP3K1 function resulted in the downregulation of Fgfr3, Fgf8, Fgf10 and Atf3 expression in the inner ear. Fgfr3, Fgf8 and Fgf10 have a role in induction of the otic placode or in otic epithelium development in mice, and their functional deficits cause defects in cochlear morphogenesis and hearing loss. Our studies suggest that MAP3K1 has an essential role in the regulation of these key cochlear morphogenesis genes. Collectively, our data highlight the crucial role of MAP3K1 in the development and function of the mouse inner ear and hearing.

  13. Efferent axons in the avian auditory nerve.

    Science.gov (United States)

    Köppl, C

    2001-05-01

    The sensory hair cells of the inner ear receive both afferent and efferent innervation. The efferent supply to the auditory organ has evolved in birds and mammals into a separate complex system, with several types of neurons of largely unknown function. In this study, the efferent axons in four different species of birds (chicken, starling, barn owl and emu) were examined anatomically. Total numbers of efferents supplying the cochlear duct (auditory basilar papilla and the vestibular lagenar macula) were determined; separate estimates of the efferents to the lagenar macula only were also derived and subtracted. The numbers for auditory efferents thus varied between 120 (chicken) and 1068 (barn owl). Considering the much larger numbers of hair cells in the basilar papilla, each efferent is predicted to branch extensively. However, pronounced species-specific differences as well as regional differences along the tonotopic gradient of the basilar papilla were documented. Myelinated and unmyelinated axons were found, with mean diameters of about 1 microm and about 0.5 microm, respectively. This suggests two basic populations of efferents, however, they did not appear to be distinguished sharply. Evidence is presented that some efferents lose their myelination at the transition from central oligodendrocyte to peripheral Schwann cell myelin. Finally, a comparison of the four bird species evaluated suggests that the efferent population with smaller, unmyelinated axons is the phylogenetically more primitive one. A new population probably arose in parallel with the evolution and differentiation of the specialized hair-cell type it innervates, the short hair cell.

  14. Integration of auditory and visual speech information

    NARCIS (Netherlands)

    Hall, M.; Smeele, P.M.T.; Kuhl, P.K.

    1998-01-01

    The integration of auditory and visual speech is observed when modes specify different places of articulation. Influences of auditory variation on integration were examined using consonant identifi-cation, plus quality and similarity ratings. Auditory identification predicted auditory-visual integra

  15. Auditory-Verbal Comprehension Development of 2-5 Year Old Normal Persian Speaking Children in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Fariba Yadegari

    2011-06-01

    Full Text Available Background and Aim: Understanding and defining developmental norms of auditory comprehension is a necessity for detecting auditory-verbal comprehension impairments in children. We hereby investigated lexical auditory development of Persian (Farsi speaking children.Methods: In this cross-sectional study, auditory comprehension of four 2-5 year old normal children of adult’s child-directed utterance at available nurseries was observed by researchers primarily to gain a great number of comprehendible words for the children of the same age. The words were classified into nouns, verbs and adjectives. Auditory-verbal comprehension task items were also considered in 2 sections of subordinates and superordinates auditory comprehension. Colored pictures were provided for each item. Thirty 2-5 year old normal children were randomly selected from nurseries all over Tehran. Children were tested by this task and subsequently, mean of their correct response were analyzed. Results: The findings revealed that there is a high positive correlation between auditory-verbal comprehension and age (r=0.804, p=0.001. Comparing children in 3 age groups of 2-3, 3-4 and 4-5 year old, showed that subordinate and superordinate auditory comprehension of the former group is significantly lower (p0.05, while the difference between subordinate and superordinate auditory comprehension was significant in all age groups (p<0.05.Conclusion: Auditory-verbal comprehension develop much faster at lower than older ages and there is no prominent difference between word linguistic classes including nouns, verbs and adjectives. Slower development of superordinate auditory comprehension implies semantic hierarchical evolution of words.

  16. Auditory short-term memory in the primate auditory cortex.

    Science.gov (United States)

    Scott, Brian H; Mishkin, Mortimer

    2016-06-01

    Sounds are fleeting, and assembling the sequence of inputs at the ear into a coherent percept requires auditory memory across various time scales. Auditory short-term memory comprises at least two components: an active ׳working memory' bolstered by rehearsal, and a sensory trace that may be passively retained. Working memory relies on representations recalled from long-term memory, and their rehearsal may require phonological mechanisms unique to humans. The sensory component, passive short-term memory (pSTM), is tractable to study in nonhuman primates, whose brain architecture and behavioral repertoire are comparable to our own. This review discusses recent advances in the behavioral and neurophysiological study of auditory memory with a focus on single-unit recordings from macaque monkeys performing delayed-match-to-sample (DMS) tasks. Monkeys appear to employ pSTM to solve these tasks, as evidenced by the impact of interfering stimuli on memory performance. In several regards, pSTM in monkeys resembles pitch memory in humans, and may engage similar neural mechanisms. Neural correlates of DMS performance have been observed throughout the auditory and prefrontal cortex, defining a network of areas supporting auditory STM with parallels to that supporting visual STM. These correlates include persistent neural firing, or a suppression of firing, during the delay period of the memory task, as well as suppression or (less commonly) enhancement of sensory responses when a sound is repeated as a ׳match' stimulus. Auditory STM is supported by a distributed temporo-frontal network in which sensitivity to stimulus history is an intrinsic feature of auditory processing. This article is part of a Special Issue entitled SI: Auditory working memory.

  17. Auditory-olfactory synesthesia coexisting with auditory-visual synesthesia.

    Science.gov (United States)

    Jackson, Thomas E; Sandramouli, Soupramanien

    2012-09-01

    Synesthesia is an unusual condition in which stimulation of one sensory modality causes an experience in another sensory modality or when a sensation in one sensory modality causes another sensation within the same modality. We describe a previously unreported association of auditory-olfactory synesthesia coexisting with auditory-visual synesthesia. Given that many types of synesthesias involve vision, it is important that the clinician provide these patients with the necessary information and support that is available.

  18. Neural Correlates of Auditory Processing, Learning and Memory Formation in Songbirds

    Science.gov (United States)

    Pinaud, R.; Terleph, T. A.; Wynne, R. D.; Tremere, L. A.

    Songbirds have emerged as powerful experimental models for the study of auditory processing of complex natural communication signals. Intact hearing is necessary for several behaviors in developing and adult animals including vocal learning, territorial defense, mate selection and individual recognition. These behaviors are thought to require the processing, discrimination and memorization of songs. Although much is known about the brain circuits that participate in sensorimotor (auditory-vocal) integration, especially the ``song-control" system, less is known about the anatomical and functional organization of central auditory pathways. Here we discuss findings associated with a telencephalic auditory area known as the caudomedial nidopallium (NCM). NCM has attracted significant interest as it exhibits functional properties that may support higher order auditory functions such as stimulus discrimination and the formation of auditory memories. NCM neurons are vigorously dr iven by auditory stimuli. Interestingly, these responses are selective to conspecific, relative to heterospecific songs and artificial stimuli. In addition, forms of experience-dependent plasticity occur in NCM and are song-specific. Finally, recent experiments employing high-throughput quantitative proteomics suggest that complex protein regulatory pathways are engaged in NCM as a result of auditory experience. These molecular cascades are likely central to experience-associated plasticity of NCM circuitry and may be part of a network of calcium-driven molecular events that support the formation of auditory memory traces.

  19. Auditory Neuropathy - A Case of Auditory Neuropathy after Hyperbilirubinemia

    Directory of Open Access Journals (Sweden)

    Maliheh Mazaher Yazdi

    2007-12-01

    Full Text Available Background and Aim: Auditory neuropathy is an hearing disorder in which peripheral hearing is normal, but the eighth nerve and brainstem are abnormal. By clinical definition, patient with this disorder have normal OAE, but exhibit an absent or severely abnormal ABR. Auditory neuropathy was first reported in the late 1970s as different methods could identify discrepancy between absent ABR and present hearing threshold. Speech understanding difficulties are worse than can be predicted from other tests of hearing function. Auditory neuropathy may also affect vestibular function. Case Report: This article presents electrophysiological and behavioral data from a case of auditory neuropathy in a child with normal hearing after bilirubinemia in a 5 years follow-up. Audiological findings demonstrate remarkable changes after multidisciplinary rehabilitation. Conclusion: auditory neuropathy may involve damage to the inner hair cells-specialized sensory cells in the inner ear that transmit information about sound through the nervous system to the brain. Other causes may include faulty connections between the inner hair cells and the nerve leading from the inner ear to the brain or damage to the nerve itself. People with auditory neuropathy have OAEs response but absent ABR and hearing loss threshold that can be permanent, get worse or get better.

  20. Musical and auditory hallucinations: A spectrum.

    Science.gov (United States)

    E Fischer, Corinne; Marchie, Anthony; Norris, Mireille

    2004-02-01

    Musical hallucinosis is a rare and poorly understood clinical phenomenon. While an association appears to exist between this phenomenon and organic brain pathology, aging and sensory impairment the precise association remains unclear. The authors present two cases of musical hallucinosis, both in elderly patients with mild-moderate cognitive impairment and mild-moderate hearing loss, who subsequently developed auditory hallucinations and in one case command hallucinations. The literature in reference to musical hallucinosis will be reviewed and a theory relating to the development of musical hallucinations will be proposed.

  1. Explicit and Latent Authority in Hierarchical Organizations

    NARCIS (Netherlands)

    van den Brink, J.R.; Gilles, R.P.

    2005-01-01

    We consider the problem of control of access to a firm's productive asset, embedding the decision makers into a structure of formal authority relationships.Within such a structure, decision makers act as principal to some decision makers, while they act as agent to other decision makers.We study und

  2. Explicit and Latent Authority in Hierarchical Organizations

    NARCIS (Netherlands)

    van den Brink, J.R.; Gilles, R.P.

    2005-01-01

    We consider the problem of control of access to a firm's productive asset, embedding the decision makers into a structure of formal authority relationships.Within such a structure, decision makers act as principal to some decision makers, while they act as agent to other decision makers.We study und

  3. Brain rhythms reveal a hierarchical network organization.

    Directory of Open Access Journals (Sweden)

    G Karl Steinke

    2011-10-01

    Full Text Available Recordings of ongoing neural activity with EEG and MEG exhibit oscillations of specific frequencies over a non-oscillatory background. The oscillations appear in the power spectrum as a collection of frequency bands that are evenly spaced on a logarithmic scale, thereby preventing mutual entrainment and cross-talk. Over the last few years, experimental, computational and theoretical studies have made substantial progress on our understanding of the biophysical mechanisms underlying the generation of network oscillations and their interactions, with emphasis on the role of neuronal synchronization. In this paper we ask a very different question. Rather than investigating how brain rhythms emerge, or whether they are necessary for neural function, we focus on what they tell us about functional brain connectivity. We hypothesized that if we were able to construct abstract networks, or "virtual brains", whose dynamics were similar to EEG/MEG recordings, those networks would share structural features among themselves, and also with real brains. Applying mathematical techniques for inverse problems, we have reverse-engineered network architectures that generate characteristic dynamics of actual brains, including spindles and sharp waves, which appear in the power spectrum as frequency bands superimposed on a non-oscillatory background dominated by low frequencies. We show that all reconstructed networks display similar topological features (e.g. structural motifs and dynamics. We have also reverse-engineered putative diseased brains (epileptic and schizophrenic, in which the oscillatory activity is altered in different ways, as reported in clinical studies. These reconstructed networks show consistent alterations of functional connectivity and dynamics. In particular, we show that the complexity of the network, quantified as proposed by Tononi, Sporns and Edelman, is a good indicator of brain fitness, since virtual brains modeling diseased states display lower complexity than virtual brains modeling normal neural function. We finally discuss the implications of our results for the neurobiology of health and disease.

  4. Hierarchical organization in aggregates of protein molecules

    DEFF Research Database (Denmark)

    Bohr, Henrik; Kyhle, Anders; Sørensen, Alexis Hammer

    1997-01-01

    The aggregation of proteins into small clusters is studied by atomic force and electron microscopy. Scaling laws and fractal behaviour in the growth of the aggregates and in the correlation between aggregates is seen. A phase diagram of the aggregation process where the protonic concentration...

  5. Translating Management Ideas in Hierarchical Organization

    DEFF Research Database (Denmark)

    Wæraas, Arild; Nielsen, Jeppe

    of Leadership Pipeline in a Danish fire department and how the translators’ approach changed over time from a modifying to a reproducing mode. The study finds that translation does not necessarily imply transformation of the management idea at every phase of the process, pointing instead to efforts of exact...

  6. Explicit and Latent Authority in Hierarchical Organizations

    NARCIS (Netherlands)

    van den Brink, J.R.; Gilles, R.P.

    2005-01-01

    We consider the problem of control of access to a firm's productive asset, embedding the decision makers into a structure of formal authority relationships.Within such a structure, decision makers act as principal to some decision makers, while they act as agent to other decision makers.We study

  7. Hierarchical partial order ranking.

    Science.gov (United States)

    Carlsen, Lars

    2008-09-01

    Assessing the potential impact on environmental and human health from the production and use of chemicals or from polluted sites involves a multi-criteria evaluation scheme. A priori several parameters are to address, e.g., production tonnage, specific release scenarios, geographical and site-specific factors in addition to various substance dependent parameters. Further socio-economic factors may be taken into consideration. The number of parameters to be included may well appear to be prohibitive for developing a sensible model. The study introduces hierarchical partial order ranking (HPOR) that remedies this problem. By HPOR the original parameters are initially grouped based on their mutual connection and a set of meta-descriptors is derived representing the ranking corresponding to the single groups of descriptors, respectively. A second partial order ranking is carried out based on the meta-descriptors, the final ranking being disclosed though average ranks. An illustrative example on the prioritization of polluted sites is given.

  8. Trees and Hierarchical Structures

    CERN Document Server

    Haeseler, Arndt

    1990-01-01

    The "raison d'etre" of hierarchical dustering theory stems from one basic phe­ nomenon: This is the notorious non-transitivity of similarity relations. In spite of the fact that very often two objects may be quite similar to a third without being that similar to each other, one still wants to dassify objects according to their similarity. This should be achieved by grouping them into a hierarchy of non-overlapping dusters such that any two objects in ~ne duster appear to be more related to each other than they are to objects outside this duster. In everyday life, as well as in essentially every field of scientific investigation, there is an urge to reduce complexity by recognizing and establishing reasonable das­ sification schemes. Unfortunately, this is counterbalanced by the experience of seemingly unavoidable deadlocks caused by the existence of sequences of objects, each comparatively similar to the next, but the last rather different from the first.

  9. Hierarchical Affinity Propagation

    CERN Document Server

    Givoni, Inmar; Frey, Brendan J

    2012-01-01

    Affinity propagation is an exemplar-based clustering algorithm that finds a set of data-points that best exemplify the data, and associates each datapoint with one exemplar. We extend affinity propagation in a principled way to solve the hierarchical clustering problem, which arises in a variety of domains including biology, sensor networks and decision making in operational research. We derive an inference algorithm that operates by propagating information up and down the hierarchy, and is efficient despite the high-order potentials required for the graphical model formulation. We demonstrate that our method outperforms greedy techniques that cluster one layer at a time. We show that on an artificial dataset designed to mimic the HIV-strain mutation dynamics, our method outperforms related methods. For real HIV sequences, where the ground truth is not available, we show our method achieves better results, in terms of the underlying objective function, and show the results correspond meaningfully to geographi...

  10. Optimisation by hierarchical search

    Science.gov (United States)

    Zintchenko, Ilia; Hastings, Matthew; Troyer, Matthias

    2015-03-01

    Finding optimal values for a set of variables relative to a cost function gives rise to some of the hardest problems in physics, computer science and applied mathematics. Although often very simple in their formulation, these problems have a complex cost function landscape which prevents currently known algorithms from efficiently finding the global optimum. Countless techniques have been proposed to partially circumvent this problem, but an efficient method is yet to be found. We present a heuristic, general purpose approach to potentially improve the performance of conventional algorithms or special purpose hardware devices by optimising groups of variables in a hierarchical way. We apply this approach to problems in combinatorial optimisation, machine learning and other fields.

  11. How hierarchical is language use?

    Science.gov (United States)

    Frank, Stefan L.; Bod, Rens; Christiansen, Morten H.

    2012-01-01

    It is generally assumed that hierarchical phrase structure plays a central role in human language. However, considerations of simplicity and evolutionary continuity suggest that hierarchical structure should not be invoked too hastily. Indeed, recent neurophysiological, behavioural and computational studies show that sequential sentence structure has considerable explanatory power and that hierarchical processing is often not involved. In this paper, we review evidence from the recent literature supporting the hypothesis that sequential structure may be fundamental to the comprehension, production and acquisition of human language. Moreover, we provide a preliminary sketch outlining a non-hierarchical model of language use and discuss its implications and testable predictions. If linguistic phenomena can be explained by sequential rather than hierarchical structure, this will have considerable impact in a wide range of fields, such as linguistics, ethology, cognitive neuroscience, psychology and computer science. PMID:22977157

  12. How hierarchical is language use?

    Science.gov (United States)

    Frank, Stefan L; Bod, Rens; Christiansen, Morten H

    2012-11-22

    It is generally assumed that hierarchical phrase structure plays a central role in human language. However, considerations of simplicity and evolutionary continuity suggest that hierarchical structure should not be invoked too hastily. Indeed, recent neurophysiological, behavioural and computational studies show that sequential sentence structure has considerable explanatory power and that hierarchical processing is often not involved. In this paper, we review evidence from the recent literature supporting the hypothesis that sequential structure may be fundamental to the comprehension, production and acquisition of human language. Moreover, we provide a preliminary sketch outlining a non-hierarchical model of language use and discuss its implications and testable predictions. If linguistic phenomena can be explained by sequential rather than hierarchical structure, this will have considerable impact in a wide range of fields, such as linguistics, ethology, cognitive neuroscience, psychology and computer science.

  13. Associative Hierarchical Random Fields.

    Science.gov (United States)

    Ladický, L'ubor; Russell, Chris; Kohli, Pushmeet; Torr, Philip H S

    2014-06-01

    This paper makes two contributions: the first is the proposal of a new model-The associative hierarchical random field (AHRF), and a novel algorithm for its optimization; the second is the application of this model to the problem of semantic segmentation. Most methods for semantic segmentation are formulated as a labeling problem for variables that might correspond to either pixels or segments such as super-pixels. It is well known that the generation of super pixel segmentations is not unique. This has motivated many researchers to use multiple super pixel segmentations for problems such as semantic segmentation or single view reconstruction. These super-pixels have not yet been combined in a principled manner, this is a difficult problem, as they may overlap, or be nested in such a way that the segmentations form a segmentation tree. Our new hierarchical random field model allows information from all of the multiple segmentations to contribute to a global energy. MAP inference in this model can be performed efficiently using powerful graph cut based move making algorithms. Our framework generalizes much of the previous work based on pixels or segments, and the resulting labelings can be viewed both as a detailed segmentation at the pixel level, or at the other extreme, as a segment selector that pieces together a solution like a jigsaw, selecting the best segments from different segmentations as pieces. We evaluate its performance on some of the most challenging data sets for object class segmentation, and show that this ability to perform inference using multiple overlapping segmentations leads to state-of-the-art results.

  14. A hierarchical neuronal model for generation and online recognition of birdsongs.

    Directory of Open Access Journals (Sweden)

    Izzet B Yildiz

    2011-12-01

    Full Text Available The neuronal system underlying learning, generation and recognition of song in birds is one of the best-studied systems in the neurosciences. Here, we use these experimental findings to derive a neurobiologically plausible, dynamic, hierarchical model of birdsong generation and transform it into a functional model of birdsong recognition. The generation model consists of neuronal rate models and includes critical anatomical components like the premotor song-control nucleus HVC (proper name, the premotor nucleus RA (robust nucleus of the arcopallium, and a model of the syringeal and respiratory organs. We use Bayesian inference of this dynamical system to derive a possible mechanism for how birds can efficiently and robustly recognize the songs of their conspecifics in an online fashion. Our results indicate that the specific way birdsong is generated enables a listening bird to robustly and rapidly perceive embedded information at multiple time scales of a song. The resulting mechanism can be useful for investigating the functional roles of auditory recognition areas and providing predictions for future birdsong experiments.

  15. Use of auditory learning to manage listening problems in children

    National Research Council Canada - National Science Library

    David R Moore; Lorna F Halliday; Sygal Amitay

    2009-01-01

    .... It considers the auditory contribution to developmental listening and language problems and the underlying principles of auditory learning that may drive further refinement of auditory learning applications...

  16. Auditory Processing Disorder (For Parents)

    Science.gov (United States)

    ... CAPD often have trouble maintaining attention, although health, motivation, and attitude also can play a role. Auditory ... programs. Several computer-assisted programs are geared toward children with APD. They mainly help the brain do ...

  17. Discovering Structure in Auditory Input: Evidence from Williams Syndrome

    Science.gov (United States)

    Elsabbagh, Mayada; Cohen, Henri; Karmiloff-Smith, Annette

    2010-01-01

    We examined auditory perception in Williams syndrome by investigating strategies used in organizing sound patterns into coherent units. In Experiment 1, we investigated the streaming of sound sequences into perceptual units, on the basis of pitch cues, in a group of children and adults with Williams syndrome compared to typical controls. We showed…

  18. Hierarchical Participation Constraints for Adaptive Learning and Coordination

    DEFF Research Database (Denmark)

    Yi, Sangyoon; Stieglitz, Nils; Knudsen, Thorbjørn

    From the knowledge-based view of competence, firms exist as an institution where knowledge accumulation and knowledge application are facilitated by organizing principles that markets cannot provide. While scholars perceive that these two interdependent knowledge processes could be influenced...... by formal aspects of organizations, the underlying mechanisms still need to be unpacked. As such an organizing principle, we suggest in this study that hierarchical participation constraints promote both adaptive learning at the individual level and dynamic coordination at the organization level...

  19. Hierarchical Dragonfly Wing: Microstructure-Biomechanical Behavior Relations

    Institute of Scientific and Technical Information of China (English)

    Yinglong Chen; Xishu Wang; Huaihui Ren; Hang Yin; Su Jia

    2012-01-01

    The dragonfly wing,which consists of veins and membrane,is of biological hierarchical material.We observed the cross-sections of longitudinal veins and membrane using Environmental Scanning Electron Microscopy (ESEM).Based on the experiments and previous studies,we described the longitudinal vein and the membrane in terms of two hierarchical levels of organization of composite materials at the micro- and nano-scales.The longitudinal vein of dragonfly wing has a complex sandwich structure with two chitinous shells and a protein layer,and it is considered as the first hierarchical level of the vein.Moreover,the chitinous shells are concentric multilayered structures.Clusters of nano-fibrils grow along the circumferential orientation embedded into the protein layer.It is considered as the second level of the hierarchy.Similarly,the upper and lower epidermises of membrane constitute the first hierarchical level of organization in micro scale.Similar to the vein shell,the membrane epidermises were found to be a paralleled multilayered structure,defined as the second hierarchical level of the membrane.Combining with the mechanical behavior analysis of the dragonfly wing,we concluded that the growth orientation of the hierarchical structure of the longitudinal vein and membrane is relevant to its biomechanical behavior.

  20. Neural Mechanisms of Hierarchical Planning in a Virtual Subway Network.

    Science.gov (United States)

    Balaguer, Jan; Spiers, Hugo; Hassabis, Demis; Summerfield, Christopher

    2016-05-18

    Planning allows actions to be structured in pursuit of a future goal. However, in natural environments, planning over multiple possible future states incurs prohibitive computational costs. To represent plans efficiently, states can be clustered hierarchically into "contexts". For example, representing a journey through a subway network as a succession of individual states (stations) is more costly than encoding a sequence of contexts (lines) and context switches (line changes). Here, using functional brain imaging, we asked humans to perform a planning task in a virtual subway network. Behavioral analyses revealed that humans executed a hierarchically organized plan. Brain activity in the dorsomedial prefrontal cortex and premotor cortex scaled with the cost of hierarchical plan representation and unique neural signals in these regions signaled contexts and context switches. These results suggest that humans represent hierarchical plans using a network of caudal prefrontal structures. VIDEO ABSTRACT.

  1. Cortical activity of children with dyslexia during natural speech processing: evidence of auditory processing deficiency.

    Science.gov (United States)

    Putter-Katz, Hanna; Kishon-Rabin, Liat; Sachartov, Emma; Shabtai, Esther L; Sadeh, Michelle; Weiz, Raphael; Gadoth, Natan; Pratt, Hillel

    2005-01-01

    Children with dyslexia have difficulties with phonological processing. It is assumed that deficits in auditory temporal processing underlie the phonological difficulties of dyslectic subjects (i.e. the processing of rapid acoustic changes that occur in speech). In this study we assessed behavioral and electrophysiological evoked brain responses of dyslectic and skilled reading children while performing a set of hierarchically structured auditory tasks. Stimuli consisted of auditory natural unmodified speech that was controlled for the parameter of changing rate of main acoustic cues: vowels (slowly changing speech cues: /i/ versus /u/) and consonant-vowel (CV) syllables (rapidly changing speech cues: /da/ versus /ga/). Brain auditory processing differed significantly between groups: reaction time of dyslectic readers was prolonged in identifying speech stimuli and increased with increased phonological demand. Latencies of auditory evoked responses (auditory event related potentials [AERPs]) recorded during syllable identification of the dyslectic group were prolonged relative to those of skilled readers. Moreover, N1 amplitudes during vowel processing were larger for the dyslectic children and P3 amplitudes during CV processing were smaller for the dyslectic children. From the results of this study it is evident that the latency and amplitude of AERPs are sensitive measures of the complexity of phonological processing in skilled and dyslectic readers. These results may be signs of deficient auditory processing of natural speech under normal listening conditions as a contributing factor to reading difficulties in dyslexia. Detecting a dysfunction in the central auditory processing pathway might lead to early detection of children who may benefit from phonetic-acoustic training methods.

  2. Modeling hierarchical structures - Hierarchical Linear Modeling using MPlus

    CERN Document Server

    Jelonek, M

    2006-01-01

    The aim of this paper is to present the technique (and its linkage with physics) of overcoming problems connected to modeling social structures, which are typically hierarchical. Hierarchical Linear Models provide a conceptual and statistical mechanism for drawing conclusions regarding the influence of phenomena at different levels of analysis. In the social sciences it is used to analyze many problems such as educational, organizational or market dilemma. This paper introduces the logic of modeling hierarchical linear equations and estimation based on MPlus software. I present my own model to illustrate the impact of different factors on school acceptation level.

  3. An auditory feature detection circuit for sound pattern recognition.

    Science.gov (United States)

    Schöneich, Stefan; Kostarakos, Konstantinos; Hedwig, Berthold

    2015-09-01

    From human language to birdsong and the chirps of insects, acoustic communication is based on amplitude and frequency modulation of sound signals. Whereas frequency processing starts at the level of the hearing organs, temporal features of the sound amplitude such as rhythms or pulse rates require processing by central auditory neurons. Besides several theoretical concepts, brain circuits that detect temporal features of a sound signal are poorly understood. We focused on acoustically communicating field crickets and show how five neurons in the brain of females form an auditory feature detector circuit for the pulse pattern of the male calling song. The processing is based on a coincidence detector mechanism that selectively responds when a direct neural response and an intrinsically delayed response to the sound pulses coincide. This circuit provides the basis for auditory mate recognition in field crickets and reveals a principal mechanism of sensory processing underlying the perception of temporal patterns.

  4. Enhanced representation of spectral contrasts in the primary auditory cortex

    Directory of Open Access Journals (Sweden)

    Nicolas eCatz

    2013-06-01

    Full Text Available The role of early auditory processing may be to extract some elementary features from an acoustic mixture in order to organize the auditory scene. To accomplish this task, the central auditory system may rely on the fact that sensory objects are often composed of spectral edges, i.e. regions where the stimulus energy changes abruptly over frequency. The processing of acoustic stimuli may benefit from a mechanism enhancing the internal representation of spectral edges. While the visual system is thought to rely heavily on this mechanism (enhancing spatial edges, it is still unclear whether a related process plays a significant role in audition. We investigated the cortical representation of spectral edges, using acoustic stimuli composed of multi-tone pips whose time-averaged spectral envelope contained suppressed or enhanced regions. Importantly, the stimuli were designed such that neural responses properties could be assessed as a function of stimulus frequency during stimulus presentation. Our results suggest that the representation of acoustic spectral edges is enhanced in the auditory cortex, and that this enhancement is sensitive to the characteristics of the spectral contrast profile, such as depth, sharpness and width. Spectral edges are maximally enhanced for sharp contrast and large depth. Cortical activity was also suppressed at frequencies within the suppressed region. To note, the suppression of firing was larger at frequencies nearby the lower edge of the suppressed region than at the upper edge. Overall, the present study gives critical insights into the processing of spectral contrasts in the auditory system.

  5. Psychology of auditory perception.

    Science.gov (United States)

    Lotto, Andrew; Holt, Lori

    2011-09-01

    Audition is often treated as a 'secondary' sensory system behind vision in the study of cognitive science. In this review, we focus on three seemingly simple perceptual tasks to demonstrate the complexity of perceptual-cognitive processing involved in everyday audition. After providing a short overview of the characteristics of sound and their neural encoding, we present a description of the perceptual task of segregating multiple sound events that are mixed together in the signal reaching the ears. Then, we discuss the ability to localize the sound source in the environment. Finally, we provide some data and theory on how listeners categorize complex sounds, such as speech. In particular, we present research on how listeners weigh multiple acoustic cues in making a categorization decision. One conclusion of this review is that it is time for auditory cognitive science to be developed to match what has been done in vision in order for us to better understand how humans communicate with speech and music. WIREs Cogni Sci 2011 2 479-489 DOI: 10.1002/wcs.123 For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.

  6. Modeling hierarchical structures - Hierarchical Linear Modeling using MPlus

    OpenAIRE

    Jelonek, Magdalena

    2006-01-01

    The aim of this paper is to present the technique (and its linkage with physics) of overcoming problems connected to modeling social structures, which are typically hierarchical. Hierarchical Linear Models provide a conceptual and statistical mechanism for drawing conclusions regarding the influence of phenomena at different levels of analysis. In the social sciences it is used to analyze many problems such as educational, organizational or market dilemma. This paper introduces the logic of m...

  7. Metal hierarchical patterning by direct nanoimprint lithography.

    Science.gov (United States)

    Radha, Boya; Lim, Su Hui; Saifullah, Mohammad S M; Kulkarni, Giridhar U

    2013-01-01

    Three-dimensional hierarchical patterning of metals is of paramount importance in diverse fields involving photonics, controlling surface wettability and wearable electronics. Conventionally, this type of structuring is tedious and usually involves layer-by-layer lithographic patterning. Here, we describe a simple process of direct nanoimprint lithography using palladium benzylthiolate, a versatile metal-organic ink, which not only leads to the formation of hierarchical patterns but also is amenable to layer-by-layer stacking of the metal over large areas. The key to achieving such multi-faceted patterning is hysteretic melting of ink, enabling its shaping. It undergoes transformation to metallic palladium under gentle thermal conditions without affecting the integrity of the hierarchical patterns on micro- as well as nanoscale. A metallic rice leaf structure showing anisotropic wetting behavior and woodpile-like structures were thus fabricated. Furthermore, this method is extendable for transferring imprinted structures to a flexible substrate to make them robust enough to sustain numerous bending cycles.

  8. Merging functional and structural properties of the monkey auditory cortex

    Directory of Open Access Journals (Sweden)

    Olivier eJoly

    2014-07-01

    Full Text Available Recent neuroimaging studies in primates aim to define the functional properties of auditory cortical areas, especially areas beyond A1, in order to further our understanding of the auditory cortical organization. Precise mapping of functional magnetic resonance imaging (fMRI results and interpretation of their localizations among all the small auditory subfields remains challenging. To facilitate this mapping, we combined here information from cortical folding, micro-anatomy, surface-based atlas and tonotopic mapping. We used for the first time, phase-encoded fMRI design for mapping the monkey tonotopic organization. From posterior to anterior, we found a high-low-high progression of frequency preference on the superior temporal plane. We show a faithful representation of the fMRI results on a locally flattened surface of the superior temporal plane. In a tentative scheme to delineate core versus belt regions which share similar tonotopic organizations we used the ratio of T1-weighted and T2-weighted MR images as a measure of cortical myelination. Our results, presented along a co-registered surface-based atlas, can be interpreted in terms of a current model of the monkey auditory cortex.

  9. Neural dynamics of phonological processing in the dorsal auditory stream.

    Science.gov (United States)

    Liebenthal, Einat; Sabri, Merav; Beardsley, Scott A; Mangalathu-Arumana, Jain; Desai, Anjali

    2013-09-25

    Neuroanatomical models hypothesize a role for the dorsal auditory pathway in phonological processing as a feedforward efferent system (Davis and Johnsrude, 2007; Rauschecker and Scott, 2009; Hickok et al., 2011). But the functional organization of the pathway, in terms of time course of interactions between auditory, somatosensory, and motor regions, and the hemispheric lateralization pattern is largely unknown. Here, ambiguous duplex syllables, with elements presented dichotically at varying interaural asynchronies, were used to parametrically modulate phonological processing and associated neural activity in the human dorsal auditory stream. Subjects performed syllable and chirp identification tasks, while event-related potentials and functional magnetic resonance images were concurrently collected. Joint independent component analysis was applied to fuse the neuroimaging data and study the neural dynamics of brain regions involved in phonological processing with high spatiotemporal resolution. Results revealed a highly interactive neural network associated with phonological processing, composed of functional fields in posterior temporal gyrus (pSTG), inferior parietal lobule (IPL), and ventral central sulcus (vCS) that were engaged early and almost simultaneously (at 80-100 ms), consistent with a direct influence of articulatory somatomotor areas on phonemic perception. Left hemispheric lateralization was observed 250 ms earlier in IPL and vCS than pSTG, suggesting that functional specialization of somatomotor (and not auditory) areas determined lateralization in the dorsal auditory pathway. The temporal dynamics of the dorsal auditory pathway described here offer a new understanding of its functional organization and demonstrate that temporal information is essential to resolve neural circuits underlying complex behaviors.

  10. Hierarchical fringe tracking

    CERN Document Server

    Petrov, Romain G; Boskri, Abdelkarim; Folcher, Jean-Pierre; Lagarde, Stephane; Bresson, Yves; Benkhaldoum, Zouhair; Lazrek, Mohamed; Rakshit, Suvendu

    2014-01-01

    The limiting magnitude is a key issue for optical interferometry. Pairwise fringe trackers based on the integrated optics concepts used for example in GRAVITY seem limited to about K=10.5 with the 8m Unit Telescopes of the VLTI, and there is a general "common sense" statement that the efficiency of fringe tracking, and hence the sensitivity of optical interferometry, must decrease as the number of apertures increases, at least in the near infrared where we are still limited by detector readout noise. Here we present a Hierarchical Fringe Tracking (HFT) concept with sensitivity at least equal to this of a two apertures fringe trackers. HFT is based of the combination of the apertures in pairs, then in pairs of pairs then in pairs of groups. The key HFT module is a device that behaves like a spatial filter for two telescopes (2TSF) and transmits all or most of the flux of a cophased pair in a single mode beam. We give an example of such an achromatic 2TSF, based on very broadband dispersed fringes analyzed by g...

  11. Onboard hierarchical network

    Science.gov (United States)

    Tunesi, Luca; Armbruster, Philippe

    2004-02-01

    The objective of this paper is to demonstrate a suitable hierarchical networking solution to improve capabilities and performances of space systems, with significant recurrent costs saving and more efficient design & manufacturing flows. Classically, a satellite can be split in two functional sub-systems: the platform and the payload complement. The platform is in charge of providing power, attitude & orbit control and up/down-link services, whereas the payload represents the scientific and/or operational instruments/transponders and embodies the objectives of the mission. One major possibility to improve the performance of payloads, by limiting the data return to pertinent information, is to process data on board thanks to a proper implementation of the payload data system. In this way, it is possible to share non-recurring development costs by exploiting a system that can be adopted by the majority of space missions. It is believed that the Modular and Scalable Payload Data System, under development by ESA, provides a suitable solution to fulfil a large range of future mission requirements. The backbone of the system is the standardised high data rate SpaceWire network http://www.ecss.nl/. As complement, a lower speed command and control bus connecting peripherals is required. For instance, at instrument level, there is a need for a "local" low complexity bus, which gives the possibility to command and control sensors and actuators. Moreover, most of the connections at sub-system level are related to discrete signals management or simple telemetry acquisitions, which can easily and efficiently be handled by a local bus. An on-board hierarchical network can therefore be defined by interconnecting high-speed links and local buses. Additionally, it is worth stressing another important aspect of the design process: Agencies and ESA in particular are frequently confronted with a big consortium of geographically spread companies located in different countries, each one

  12. Hierarchical Reverberation Mapping

    CERN Document Server

    Brewer, Brendon J

    2013-01-01

    Reverberation mapping (RM) is an important technique in studies of active galactic nuclei (AGN). The key idea of RM is to measure the time lag $\\tau$ between variations in the continuum emission from the accretion disc and subsequent response of the broad line region (BLR). The measurement of $\\tau$ is typically used to estimate the physical size of the BLR and is combined with other measurements to estimate the black hole mass $M_{\\rm BH}$. A major difficulty with RM campaigns is the large amount of data needed to measure $\\tau$. Recently, Fine et al (2012) introduced a new approach to RM where the BLR light curve is sparsely sampled, but this is counteracted by observing a large sample of AGN, rather than a single system. The results are combined to infer properties of the sample of AGN. In this letter we implement this method using a hierarchical Bayesian model and contrast this with the results from the previous stacked cross-correlation technique. We find that our inferences are more precise and allow fo...

  13. Topography of acoustic response characteristics in the auditory cortex of the Kunming mouse

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Topography of acoustic response characteristics in the auditory cortex (AC) of the Kunming (KM) mouse has been examined by using microelectrode recording techniques.Based on best-frequency (BF) maps,both the primary auditory field (AⅠ) and the anterior auditory field (AAF) are tonotopically organized with a counter running frequency gradient.Within an isofrequency stripe,the width of the frequency-threshold curves of single neurons increases,and minimum threshold (MT) decreases towards more ventral locations.BFs in AⅠand AAF range from 4 to 38 kHz.Auditory neurons with BFs above 40 kHz are located at the rostrodorsal part of the AC.The findings suggest that the KM mouse is a good model suitable for auditory research.

  14. 树形层次化组织机构中的分级访问控制模型%Multi-level access control model for tree-like hierarchical organizations

    Institute of Scientific and Technical Information of China (English)

    於光灿; 李瑞轩; 卢正鼎; Mudar Sarem; 宋伟; 苏永红

    2008-01-01

    在BLP模型基础上提出一个新的分级访问控制模型,模型中建立部门之间的层次关系,提出岗位这一新的概念,简化了安全标记指派这一烦琐工作.通过为岗位指派多个安全标记,实现上下级及平级部门之间的互相沟通,在树形层次中靠得越近的部门,其职员之间可交流的客体密级越高.定义3个层次的访问矩阵.实现多种粒度的灵活的自主访问控制.模型在增加灵活性和实用性的同时保证信息的流动始终处于系统的控制之下.继承了BLP模型最突出的优点,并通过形式化证明的方式对模型进行了验证.%An access control model is proposed based on the famous Bell-LaPadula (BLP) model. In the proposed model, hierarchical relationships among departments are built, a new concept named post is proposed, and assigning security tags to subjects and objects is greatly simplified. The interoperation among different departments is implemented through assigning multiple security tags to one post, and the more departments are dosed on the organization tree, the more secret objects can be exchanged by the staff of the departments. The access control matrices of the department, post and staff are defined. By using the three access control matrices, a multi granularity and flexible discretionary access control policy is implemented. The outstanding merit of the BLP model is inherited, and the new model can guarantee that all the information flow is under control. Finally, our study shows that compared to the BLP model, the proposed model is more flexible.

  15. Exposure to a novel stimulus environment alters patterns of lateralization in avian auditory cortex.

    Science.gov (United States)

    Yang, L M; Vicario, D S

    2015-01-29

    Perceptual filters formed early in development provide an initial means of parsing the incoming auditory stream. However, these filters may not remain fixed, and may be updated by subsequent auditory input, such that, even in an adult organism, the auditory system undergoes plastic changes to achieve a more efficient representation of the recent auditory environment. Songbirds are an excellent model system for experimental studies of auditory phenomena due to many parallels between song learning in birds and language acquisition in humans. In the present study, we explored the effects of passive immersion in a novel heterospecific auditory environment on neural responses in caudo-medial neostriatum (NCM), a songbird auditory area similar to the secondary auditory cortex in mammals. In zebra finches, a well-studied species of songbirds, NCM responds selectively to conspecific songs and contains a neuronal memory for tutor and other familiar conspecific songs. Adult male zebra finches were randomly assigned to either a conspecific or heterospecific auditory environment. After 2, 4 or 9 days of exposure, subjects were presented with heterospecific and conspecific songs during awake electrophysiological recording. The neural response strength and rate of adaptation to the testing stimuli were recorded bilaterally. Controls exposed to conspecific environment sounds exhibited the normal pattern of hemispheric lateralization with higher absolute response strength and faster adaptation in the right hemisphere. The pattern of lateralization was fully reversed in birds exposed to heterospecific environment for 4 or 9 days and partially reversed in birds exposed to heterospecific environment for 2 days. Our results show that brief passive exposure to a novel category of sounds was sufficient to induce a gradual reorganization of the left and right secondary auditory cortices. These changes may reflect modification of perceptual filters to form a more efficient representation

  16. Hierarchical materials: Background and perspectives

    DEFF Research Database (Denmark)

    2016-01-01

    Hierarchical design draws inspiration from analysis of biological materials and has opened new possibilities for enhancing performance and enabling new functionalities and extraordinary properties. With the development of nanotechnology, the necessary technological requirements for the manufactur...

  17. Hierarchical clustering for graph visualization

    CERN Document Server

    Clémençon, Stéphan; Rossi, Fabrice; Tran, Viet Chi

    2012-01-01

    This paper describes a graph visualization methodology based on hierarchical maximal modularity clustering, with interactive and significant coarsening and refining possibilities. An application of this method to HIV epidemic analysis in Cuba is outlined.

  18. Direct hierarchical assembly of nanoparticles

    Science.gov (United States)

    Xu, Ting; Zhao, Yue; Thorkelsson, Kari

    2014-07-22

    The present invention provides hierarchical assemblies of a block copolymer, a bifunctional linking compound and a nanoparticle. The block copolymers form one micro-domain and the nanoparticles another micro-domain.

  19. Cortical oscillations in auditory perception and speech: evidence for two temporal windows in human auditory cortex

    Directory of Open Access Journals (Sweden)

    Huan eLuo

    2012-05-01

    Full Text Available Natural sounds, including vocal communication sounds, contain critical information at multiple time scales. Two essential temporal modulation rates in speech have been argued to be in the low gamma band (~20-80 ms duration information and the theta band (~150-300 ms, corresponding to segmental and syllabic modulation rates, respectively. On one hypothesis, auditory cortex implements temporal integration using time constants closely related to these values. The neural correlates of a proposed dual temporal window mechanism in human auditory cortex remain poorly understood. We recorded MEG responses from participants listening to non-speech auditory stimuli with different temporal structures, created by concatenating frequency-modulated segments of varied segment durations. We show that these non-speech stimuli with temporal structure matching speech-relevant scales (~25 ms and ~200 ms elicit reliable phase tracking in the corresponding associated oscillatory frequencies (low gamma and theta bands. In contrast, stimuli with non-matching temporal structure do not. Furthermore, the topography of theta band phase tracking shows rightward lateralization while gamma band phase tracking occurs bilaterally. The results support the hypothesis that there exists multi-time resolution processing in cortex on discontinuous scales and provide evidence for an asymmetric organization of temporal analysis (asymmetrical sampling in time, AST. The data argue for a macroscopic-level neural mechanism underlying multi-time resolution processing: the sliding and resetting of intrinsic temporal windows on privileged time scales.

  20. Hierarchical Neural Regression Models for Customer Churn Prediction

    Directory of Open Access Journals (Sweden)

    Golshan Mohammadi

    2013-01-01

    Full Text Available As customers are the main assets of each industry, customer churn prediction is becoming a major task for companies to remain in competition with competitors. In the literature, the better applicability and efficiency of hierarchical data mining techniques has been reported. This paper considers three hierarchical models by combining four different data mining techniques for churn prediction, which are backpropagation artificial neural networks (ANN, self-organizing maps (SOM, alpha-cut fuzzy c-means (α-FCM, and Cox proportional hazards regression model. The hierarchical models are ANN + ANN + Cox, SOM + ANN + Cox, and α-FCM + ANN + Cox. In particular, the first component of the models aims to cluster data in two churner and nonchurner groups and also filter out unrepresentative data or outliers. Then, the clustered data as the outputs are used to assign customers to churner and nonchurner groups by the second technique. Finally, the correctly classified data are used to create Cox proportional hazards model. To evaluate the performance of the hierarchical models, an Iranian mobile dataset is considered. The experimental results show that the hierarchical models outperform the single Cox regression baseline model in terms of prediction accuracy, Types I and II errors, RMSE, and MAD metrics. In addition, the α-FCM + ANN + Cox model significantly performs better than the two other hierarchical models.

  1. Effects of chronic stress on the auditory system and fear learning: an evolutionary approach.

    Science.gov (United States)

    Dagnino-Subiabre, Alexies

    2013-01-01

    Stress is a complex biological reaction common to all living organisms that allows them to adapt to their environments. Chronic stress alters the dendritic architecture and function of the limbic brain areas that affect memory, learning, and emotional processing. This review summarizes our research about chronic stress effects on the auditory system, providing the details of how we developed the main hypotheses that currently guide our research. The aims of our studies are to (1) determine how chronic stress impairs the dendritic morphology of the main nuclei of the rat auditory system, the inferior colliculus (auditory mesencephalon), the medial geniculate nucleus (auditory thalamus), and the primary auditory cortex; (2) correlate the anatomic alterations with the impairments of auditory fear learning; and (3) investigate how the stress-induced alterations in the rat limbic system may spread to nonlimbic areas, affecting specific sensory system, such as the auditory and olfactory systems, and complex cognitive functions, such as auditory attention. Finally, this article gives a new evolutionary approach to understanding the neurobiology of stress and the stress-related disorders.

  2. Effects of aging on peripheral and central auditory processing in rats.

    Science.gov (United States)

    Costa, Margarida; Lepore, Franco; Prévost, François; Guillemot, Jean-Paul

    2016-08-01

    Hearing loss is a hallmark sign in the elderly population. Decline in auditory perception provokes deficits in the ability to localize sound sources and reduces speech perception, particularly in noise. In addition to a loss of peripheral hearing sensitivity, changes in more complex central structures have also been demonstrated. Related to these, this study examines the auditory directional maps in the deep layers of the superior colliculus of the rat. Hence, anesthetized Sprague-Dawley adult (10 months) and aged (22 months) rats underwent distortion product of otoacoustic emissions (DPOAEs) to assess cochlear function. Then, auditory brainstem responses (ABRs) were assessed, followed by extracellular single-unit recordings to determine age-related effects on central auditory functions. DPOAE amplitude levels were decreased in aged rats although they were still present between 3.0 and 24.0 kHz. ABR level thresholds in aged rats were significantly elevated at an early (cochlear nucleus - wave II) stage in the auditory brainstem. In the superior colliculus, thresholds were increased and the tuning widths of the directional receptive fields were significantly wider. Moreover, no systematic directional spatial arrangement was present among the neurons of the aged rats, implying that the topographical organization of the auditory directional map was abolished. These results suggest that the deterioration of the auditory directional spatial map can, to some extent, be attributable to age-related dysfunction at more central, perceptual stages of auditory processing.

  3. Advanced hierarchical distance sampling

    Science.gov (United States)

    Royle, Andy

    2016-01-01

    In this chapter, we cover a number of important extensions of the basic hierarchical distance-sampling (HDS) framework from Chapter 8. First, we discuss the inclusion of “individual covariates,” such as group size, in the HDS model. This is important in many surveys where animals form natural groups that are the primary observation unit, with the size of the group expected to have some influence on detectability. We also discuss HDS integrated with time-removal and double-observer or capture-recapture sampling. These “combined protocols” can be formulated as HDS models with individual covariates, and thus they have a commonality with HDS models involving group structure (group size being just another individual covariate). We cover several varieties of open-population HDS models that accommodate population dynamics. On one end of the spectrum, we cover models that allow replicate distance sampling surveys within a year, which estimate abundance relative to availability and temporary emigration through time. We consider a robust design version of that model. We then consider models with explicit dynamics based on the Dail and Madsen (2011) model and the work of Sollmann et al. (2015). The final major theme of this chapter is relatively newly developed spatial distance sampling models that accommodate explicit models describing the spatial distribution of individuals known as Point Process models. We provide novel formulations of spatial DS and HDS models in this chapter, including implementations of those models in the unmarked package using a hack of the pcount function for N-mixture models.

  4. Auditory Hallucinations in Acute Stroke

    Directory of Open Access Journals (Sweden)

    Yair Lampl

    2005-01-01

    Full Text Available Auditory hallucinations are uncommon phenomena which can be directly caused by acute stroke, mostly described after lesions of the brain stem, very rarely reported after cortical strokes. The purpose of this study is to determine the frequency of this phenomenon. In a cross sectional study, 641 stroke patients were followed in the period between 1996–2000. Each patient underwent comprehensive investigation and follow-up. Four patients were found to have post cortical stroke auditory hallucinations. All of them occurred after an ischemic lesion of the right temporal lobe. After no more than four months, all patients were symptom-free and without therapy. The fact the auditory hallucinations may be of cortical origin must be taken into consideration in the treatment of stroke patients. The phenomenon may be completely reversible after a couple of months.

  5. Synthesis strategies in the search for hierarchical zeolites.

    Science.gov (United States)

    Serrano, D P; Escola, J M; Pizarro, P

    2013-05-07

    Great interest has arisen in the past years in the development of hierarchical zeolites, having at least two levels of porosities. Hierarchical zeolites show an enhanced accessibility, leading to improved catalytic activity in reactions suffering from steric and/or diffusional limitations. Moreover, the secondary porosity offers an ideal space for the deposition of additional active phases and for functionalization with organic moieties. However, the secondary surface represents a discontinuity of the crystalline framework, with a low connectivity and a high concentration of silanols. Consequently, hierarchical zeolites exhibit a less "zeolitic behaviour" than conventional ones in terms of acidity, hydrophobic/hydrophilic character, confinement effects, shape-selectivity and hydrothermal stability. Nevertheless, this secondary surface is far from being amorphous, which provides hierarchical zeolites with a set of novel features. A wide variety of innovative strategies have been developed for generating a secondary porosity in zeolites. In the present review, the different synthetic routes leading to hierarchical zeolites have been classified into five categories: removal of framework atoms, surfactant-assisted procedures, hard-templating, zeolitization of preformed solids and organosilane-based methods. Significant advances have been achieved recently in several of these alternatives. These include desilication, due to its versatility, dual templating with polyquaternary ammonium surfactants and framework reorganization by treatment with surfactant-containing basic solutions. In the last two cases, the materials so prepared show both mesoscopic ordering and zeolitic lattice planes. Likewise, interesting results have been obtained with the incorporation of different types of organosilanes into the zeolite crystallization gels, taking advantage of their high affinity for silicate and aluminosilicate species. Crystallization of organofunctionalized species favours the

  6. Effects of Auditory Input in Individuation Tasks

    Science.gov (United States)

    Robinson, Christopher W.; Sloutsky, Vladimir M.

    2008-01-01

    Under many conditions auditory input interferes with visual processing, especially early in development. These interference effects are often more pronounced when the auditory input is unfamiliar than when the auditory input is familiar (e.g. human speech, pre-familiarized sounds, etc.). The current study extends this research by examining how…

  7. Biominerals--hierarchical nanocomposites: the example of bone.

    Science.gov (United States)

    Beniash, Elia

    2011-01-01

    Many organisms incorporate inorganic solids in their tissues to enhance their functional, primarily mechanical, properties. These mineralized tissues, also called biominerals, are unique organo-mineral nanocomposites, organized at several hierarchical levels, from nano- to macroscale. Unlike man-made composite materials, which often are simple physical blends of their components, the organic and inorganic phases in biominerals interface at the molecular level. Although these tissues are made of relatively weak components under ambient conditions, their hierarchical structural organization and intimate interactions between different elements lead to superior mechanical properties. Understanding basic principles of formation, structure, and functional properties of these tissues might lead to novel bioinspired strategies for material design and better treatments for diseases of the mineralized tissues. This review focuses on general principles of structural organization, formation, and functional properties of biominerals on the example the bone tissues.

  8. Hierarchical topic modeling with nested hierarchical Dirichlet process

    Institute of Scientific and Technical Information of China (English)

    Yi-qun DING; Shan-ping LI; Zhen ZHANG; Bin SHEN

    2009-01-01

    This paper deals with the statistical modeling of latent topic hierarchies in text corpora. The height of the topic tree is assumed as fixed, while the number of topics on each level as unknown a priori and to be inferred from data. Taking a nonparametric Bayesian approach to this problem, we propose a new probabilistic generative model based on the nested hierarchical Dirichlet process (nHDP) and present a Markov chain Monte Carlo sampling algorithm for the inference of the topic tree structure as welt as the word distribution of each topic and topic distribution of each document. Our theoretical analysis and experiment results show that this model can produce a more compact hierarchical topic structure and captures more free-grained topic relationships compared to the hierarchical latent Dirichlet allocation model.

  9. Hierarchical processing in the prefrontal cortex in a variety of cognitive domains

    Directory of Open Access Journals (Sweden)

    Hyeon-Ae eJeon

    2014-11-01

    Full Text Available This review scrutinizes several findings on human hierarchical processing within the prefrontal cortex (PFC in diverse cognitive domains. Converging evidence from previous studies has shown that the PFC, specifically Brodmann area (BA 44, may function as the essential region for hierarchical processing across the domains. In language fMRI studies, BA 44 was significantly activated for the hierarchical processing of center-embedded sentences and this pattern of activations was also observed in artificial grammar. The same pattern was observed in the visuo-spatial domain where BA44 was actively involved in the processing of hierarchy for the visual symbol. Musical syntax, which is the rule-based arrangement of musical sets, has also been construed as hierarchical processing as in the language domain such that the activation in BA44 was observed in a chord sequence paradigm. P600 ERP was also engendered during the processing of musical hierarchy. Along with a longstanding idea that a human’s number faculty is developed as a by-product of language faculty, BA44 was closely involved in hierarchical processing in mental arithmetic. This review extended its discussion of hierarchical processing to hierarchical behavior, that is, human action which has been referred to as being hierarchically composed. Several lesion and TMS studies supported the involvement of BA44 for hierarchical processing in the action domain. Lastly, the hierarchical organization of cognitive controls was discussed within the PFC, forming a cascade of top-down hierarchical processes operating along a posterior-to-anterior axis of the lateral PFC including BA44 within the network. It is proposed that PFC is actively involved in different forms of hierarchical processing and specifically BA44 may play an integral role in the process. Taking levels of proficiency and subcortical areas into consideration may provide further insight into the functional role of BA44 for hierarchical

  10. Auditory and audio-visual processing in patients with cochlear, auditory brainstem, and auditory midbrain implants: An EEG study.

    Science.gov (United States)

    Schierholz, Irina; Finke, Mareike; Kral, Andrej; Büchner, Andreas; Rach, Stefan; Lenarz, Thomas; Dengler, Reinhard; Sandmann, Pascale

    2017-04-01

    There is substantial variability in speech recognition ability across patients with cochlear implants (CIs), auditory brainstem implants (ABIs), and auditory midbrain implants (AMIs). To better understand how this variability is related to central processing differences, the current electroencephalography (EEG) study compared hearing abilities and auditory-cortex activation in patients with electrical stimulation at different sites of the auditory pathway. Three different groups of patients with auditory implants (Hannover Medical School; ABI: n = 6, CI: n = 6; AMI: n = 2) performed a speeded response task and a speech recognition test with auditory, visual, and audio-visual stimuli. Behavioral performance and cortical processing of auditory and audio-visual stimuli were compared between groups. ABI and AMI patients showed prolonged response times on auditory and audio-visual stimuli compared with NH listeners and CI patients. This was confirmed by prolonged N1 latencies and reduced N1 amplitudes in ABI and AMI patients. However, patients with central auditory implants showed a remarkable gain in performance when visual and auditory input was combined, in both speech and non-speech conditions, which was reflected by a strong visual modulation of auditory-cortex activation in these individuals. In sum, the results suggest that the behavioral improvement for audio-visual conditions in central auditory implant patients is based on enhanced audio-visual interactions in the auditory cortex. Their findings may provide important implications for the optimization of electrical stimulation and rehabilitation strategies in patients with central auditory prostheses. Hum Brain Mapp 38:2206-2225, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  11. Perception of Complex Auditory Scenes

    Science.gov (United States)

    2014-07-02

    facility is a 4.3-m diameter geodesic sphere housed in an anechoic chamber. 277 Bose 11-cm full –range loudspeakers are mounted on the surface of the...conduction to loudness judgments, hearing damage risk criteria, and auditory localization. The purpose of this line of research was to develop and

  12. Auditory Hallucinations Nomenclature and Classification

    NARCIS (Netherlands)

    Blom, Jan Dirk; Sommer, Iris E. C.

    2010-01-01

    Introduction: The literature on the possible neurobiologic correlates of auditory hallucinations is expanding rapidly. For an adequate understanding and linking of this emerging knowledge, a clear and uniform nomenclature is a prerequisite. The primary purpose of the present article is to provide an

  13. Auditory Temporal Conditioning in Neonates.

    Science.gov (United States)

    Franz, W. K.; And Others

    Twenty normal newborns, approximately 36 hours old, were tested using an auditory temporal conditioning paradigm which consisted of a slow rise, 75 db tone played for five seconds every 25 seconds, ten times. Responses to the tones were measured by instantaneous, beat-to-beat heartrate; and the test trial was designated as the 2 1/2-second period…

  14. Nigel: A Severe Auditory Dyslexic

    Science.gov (United States)

    Cotterell, Gill

    1976-01-01

    Reported is the case study of a boy with severe auditory dyslexia who received remedial treatment from the age of four and progressed through courses at a technical college and a 3-year apprenticeship course in mechanics by the age of eighteen. (IM)

  15. Molecular approach of auditory neuropathy.

    Science.gov (United States)

    Silva, Magali Aparecida Orate Menezes da; Piatto, Vânia Belintani; Maniglia, Jose Victor

    2015-01-01

    Mutations in the otoferlin gene are responsible for auditory neuropathy. To investigate the prevalence of mutations in the mutations in the otoferlin gene in patients with and without auditory neuropathy. This original cross-sectional case study evaluated 16 index cases with auditory neuropathy, 13 patients with sensorineural hearing loss, and 20 normal-hearing subjects. DNA was extracted from peripheral blood leukocytes, and the mutations in the otoferlin gene sites were amplified by polymerase chain reaction/restriction fragment length polymorphism. The 16 index cases included nine (56%) females and seven (44%) males. The 13 deaf patients comprised seven (54%) males and six (46%) females. Among the 20 normal-hearing subjects, 13 (65%) were males and seven were (35%) females. Thirteen (81%) index cases had wild-type genotype (AA) and three (19%) had the heterozygous AG genotype for IVS8-2A-G (intron 8) mutation. The 5473C-G (exon 44) mutation was found in a heterozygous state (CG) in seven (44%) index cases and nine (56%) had the wild-type allele (CC). Of these mutants, two (25%) were compound heterozygotes for the mutations found in intron 8 and exon 44. All patients with sensorineural hearing loss and normal-hearing individuals did not have mutations (100%). There are differences at the molecular level in patients with and without auditory neuropathy. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  16. Auditory Hallucinations Nomenclature and Classification

    NARCIS (Netherlands)

    Blom, Jan Dirk; Sommer, Iris E. C.

    Introduction: The literature on the possible neurobiologic correlates of auditory hallucinations is expanding rapidly. For an adequate understanding and linking of this emerging knowledge, a clear and uniform nomenclature is a prerequisite. The primary purpose of the present article is to provide an

  17. Dynamics of auditory working memory

    Directory of Open Access Journals (Sweden)

    Jochen eKaiser

    2015-05-01

    Full Text Available Working memory denotes the ability to retain stimuli in mind that are no longer physically present and to perform mental operations on them. Electro- and magnetoencephalography allow investigating the short-term maintenance of acoustic stimuli at a high temporal resolution. Studies investigating working memory for non-spatial and spatial auditory information have suggested differential roles of regions along the putative auditory ventral and dorsal streams, respectively, in the processing of the different sound properties. Analyses of event-related potentials have shown sustained, memory load-dependent deflections over the retention periods. The topography of these waves suggested an involvement of modality-specific sensory storage regions. Spectral analysis has yielded information about the temporal dynamics of auditory working memory processing of individual stimuli, showing activation peaks during the delay phase whose timing was related to task performance. Coherence at different frequencies was enhanced between frontal and sensory cortex. In summary, auditory working memory seems to rely on the dynamic interplay between frontal executive systems and sensory representation regions.

  18. Molecular approach of auditory neuropathy

    Directory of Open Access Journals (Sweden)

    Magali Aparecida Orate Menezes da Silva

    2015-06-01

    Full Text Available INTRODUCTION: Mutations in the otoferlin gene are responsible for auditory neuropathy. OBJECTIVE: To investigate the prevalence of mutations in the mutations in the otoferlin gene in patients with and without auditory neuropathy. METHODS: This original cross-sectional case study evaluated 16 index cases with auditory neuropathy, 13 patients with sensorineural hearing loss, and 20 normal-hearing subjects. DNA was extracted from peripheral blood leukocytes, and the mutations in the otoferlin gene sites were amplified by polymerase chain reaction/restriction fragment length polymorphism. RESULTS: The 16 index cases included nine (56% females and seven (44% males. The 13 deaf patients comprised seven (54% males and six (46% females. Among the 20 normal-hearing subjects, 13 (65% were males and seven were (35% females. Thirteen (81% index cases had wild-type genotype (AA and three (19% had the heterozygous AG genotype for IVS8-2A-G (intron 8 mutation. The 5473C-G (exon 44 mutation was found in a heterozygous state (CG in seven (44% index cases and nine (56% had the wild-type allele (CC. Of these mutants, two (25% were compound heterozygotes for the mutations found in intron 8 and exon 44. All patients with sensorineural hearing loss and normal-hearing individuals did not have mutations (100%. CONCLUSION: There are differences at the molecular level in patients with and without auditory neuropathy.

  19. Deliberate change without hierarchical influence?

    DEFF Research Database (Denmark)

    Nørskov, Sladjana; Kesting, Peter; Ulhøi, John Parm

    2017-01-01

    Purpose This paper aims to present that deliberate change is strongly associated with formal structures and top-down influence. Hierarchical configurations have been used to structure processes, overcome resistance and get things done. But is deliberate change also possible without formal...... reveals that deliberate change is indeed achievable in a non-hierarchical collaborative OSS community context. However, it presupposes the presence and active involvement of informal change agents. The paper identifies and specifies four key drivers for change agents’ influence. Originality....../value The findings contribute to organisational analysis by providing a deeper understanding of the importance of leadership in making deliberate change possible in non-hierarchical settings. It points to the importance of “change-by-conviction”, essentially based on voluntary behaviour. This can open the door...

  20. Static Correctness of Hierarchical Procedures

    DEFF Research Database (Denmark)

    Schwartzbach, Michael Ignatieff

    1990-01-01

    A system of hierarchical, fully recursive types in a truly imperative language allows program fragments written for small types to be reused for all larger types. To exploit this property to enable type-safe hierarchical procedures, it is necessary to impose a static requirement on procedure calls....... We introduce an example language and prove the existence of a sound requirement which preserves static correctness while allowing hierarchical procedures. This requirement is further shown to be optimal, in the sense that it imposes as few restrictions as possible. This establishes the theoretical...... basis for a general type hierarchy with static type checking, which enables first-order polymorphism combined with multiple inheritance and specialization in a language with assignments. We extend the results to include opaque types. An opaque version of a type is different from the original but has...

  1. Big Data Processing in Complex Hierarchical Network Systems

    CERN Document Server

    Polishchuk, Olexandr; Tyutyunnyk, Maria; Yadzhak, Mykhailo

    2016-01-01

    This article covers the problem of processing of Big Data that describe process of complex networks and network systems operation. It also introduces the notion of hierarchical network systems combination into associations and conglomerates alongside with complex networks combination into multiplexes. The analysis is provided for methods of global network structures study depending on the purpose of the research. Also the main types of information flows in complex hierarchical network systems being the basic components of associations and conglomerates are covered. Approaches are proposed for creation of efficient computing environments, distributed computations organization and information processing methods parallelization at different levels of system hierarchy.

  2. The encoding of auditory objects in auditory cortex: insights from magnetoencephalography.

    Science.gov (United States)

    Simon, Jonathan Z

    2015-02-01

    Auditory objects, like their visual counterparts, are perceptually defined constructs, but nevertheless must arise from underlying neural circuitry. Using magnetoencephalography (MEG) recordings of the neural responses of human subjects listening to complex auditory scenes, we review studies that demonstrate that auditory objects are indeed neurally represented in auditory cortex. The studies use neural responses obtained from different experiments in which subjects selectively listen to one of two competing auditory streams embedded in a variety of auditory scenes. The auditory streams overlap spatially and often spectrally. In particular, the studies demonstrate that selective attentional gain does not act globally on the entire auditory scene, but rather acts differentially on the separate auditory streams. This stream-based attentional gain is then used as a tool to individually analyze the different neural representations of the competing auditory streams. The neural representation of the attended stream, located in posterior auditory cortex, dominates the neural responses. Critically, when the intensities of the attended and background streams are separately varied over a wide intensity range, the neural representation of the attended speech adapts only to the intensity of that speaker, irrespective of the intensity of the background speaker. This demonstrates object-level intensity gain control in addition to the above object-level selective attentional gain. Overall, these results indicate that concurrently streaming auditory objects, even if spectrally overlapping and not resolvable at the auditory periphery, are individually neurally encoded in auditory cortex, as separate objects. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Structural integrity of hierarchical composites

    Directory of Open Access Journals (Sweden)

    Marco Paggi

    2012-01-01

    Full Text Available Interface mechanical problems are of paramount importance in engineering and materials science. Traditionally, due to the complexity of modelling their mechanical behaviour, interfaces are often treated as defects and their features are not explored. In this study, a different approach is illustrated, where the interfaces play an active role in the design of innovative hierarchical composites and are fundamental for their structural integrity. Numerical examples regarding cutting tools made of hierarchical cellular polycrystalline materials are proposed, showing that tailoring of interface properties at the different scales is the way to achieve superior mechanical responses that cannot be obtained using standard materials

  4. Repetition suppression and expectation suppression are dissociable in time in early auditory evoked fields.

    Science.gov (United States)

    Todorovic, Ana; de Lange, Floris P

    2012-09-26

    Repetition of a stimulus, as well as valid expectation that a stimulus will occur, both attenuate the neural response to it. These effects, repetition suppression and expectation suppression, are typically confounded in paradigms in which the nonrepeated stimulus is also relatively rare (e.g., in oddball blocks of mismatch negativity paradigms, or in repetition suppression paradigms with multiple repetitions before an alternation). However, recent hierarchical models of sensory processing inspire the hypothesis that the two might be separable in time, with repetition suppression occurring earlier, as a consequence of local transition probabilities, and suppression by expectation occurring later, as a consequence of learnt statistical regularities. Here we test this hypothesis in an auditory experiment by orthogonally manipulating stimulus repetition and stimulus expectation and, using magnetoencephalography, measuring the neural response over time in human subjects. We found that stimulus repetition (but not stimulus expectation) attenuates the early auditory response (40-60 ms), while stimulus expectation (but not stimulus repetition) attenuates the subsequent, intermediate stage of auditory processing (100-200 ms). These findings are well in line with hierarchical predictive coding models, which posit sequential stages of prediction error resolution, contingent on the level at which the hypothesis is generated.

  5. Segmental processing in the human auditory dorsal stream.

    Science.gov (United States)

    Zaehle, Tino; Geiser, Eveline; Alter, Kai; Jancke, Lutz; Meyer, Martin

    2008-07-18

    In the present study we investigated the functional organization of sublexical auditory perception with specific respect to auditory spectro-temporal processing in speech and non-speech sounds. Participants discriminated verbal and nonverbal auditory stimuli according to either spectral or temporal acoustic features in the context of a sparse event-related functional magnetic resonance imaging (fMRI) study. Based on recent models of speech processing, we hypothesized that auditory segmental processing, as is required in the discrimination of speech and non-speech sound according to its temporal features, will lead to a specific involvement of a left-hemispheric dorsal processing network comprising the posterior portion of the inferior frontal cortex and the inferior parietal lobe. In agreement with our hypothesis results revealed significant responses in the posterior part of the inferior frontal gyrus and the parietal operculum of the left hemisphere when participants had to discriminate speech and non-speech stimuli based on subtle temporal acoustic features. In contrast, when participants had to discriminate speech and non-speech stimuli on the basis of changes in the frequency content, we observed bilateral activations along the middle temporal gyrus and superior temporal sulcus. The results of the present study demonstrate an involvement of the dorsal pathway in the segmental sublexical analysis of speech sounds as well as in the segmental acoustic analysis of non-speech sounds with analogous spectro-temporal characteristics.

  6. Brainstem auditory evoked potential abnormalities in type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Sharat Gupta

    2013-01-01

    Full Text Available Background: Diabetes mellitus represents a syndrome complex in which multiple organ systems, including the central nervous system, are affected. Aim: The study was conducted to determine the changes in the brainstem auditory evoked potentials in type 2 diabetes mellitus. Materials and Methods: A cross sectional study was conducted on 126 diabetic males, aged 35-50 years, and 106 age-matched, healthy male volunteers. Brainstem auditory evoked potentials were recorded and the results were analyzed statistically using student′s unpaired t-test. The data consisted of wave latencies I, II, III, IV, V and interpeak latencies I-III, III-V and I-V, separately for both ears. Results: The latency of wave IV was significantly delayed only in the right ear, while the latency of waves III, V and interpeak latencies III-V, I-V showed a significant delay bilaterally in diabetic males. However, no significant difference was found between diabetic and control subjects as regards to the latency of wave IV unilaterally in the left ear and the latencies of waves I, II and interpeak latency I-III bilaterally. Conclusion: Diabetes patients have an early involvement of central auditory pathway, which can be detected with fair accuracy with auditory evoked potential studies.

  7. Formation of the avian nucleus magnocellularis from the auditory anlage.

    Science.gov (United States)

    Hendricks, Susan J; Rubel, Edwin W; Nishi, Rae

    2006-10-01

    In the avian auditory system, the neural network for computing the localization of sound in space begins with bilateral innervation of nucleus laminaris (NL) by nucleus magnocellularis (NM) neurons. We used antibodies against the neural specific markers Hu C/D, neurofilament, and SV2 together with retrograde fluorescent dextran labeling from the contralateral hindbrain to identify NM neurons within the anlage and follow their development. NM neurons could be identified by retrograde labeling as early as embryonic day (E) 6. While the auditory anlage organized itself into NM and NL in a rostral-to-caudal fashion between E6 and E8, labeled NM neurons were visible throughout the extent of the anlage at E6. By observing the pattern of neuronal rearrangements together with the pattern of contralaterally projecting NM fibers, we could identify NL in the ventral anlage. Ipsilateral NM fibers contacted the developing NL at E8, well after NM collaterals had projected contralaterally. Furthermore, the formation of ipsilateral connections between NM and NL neurons appeared to coincide with the arrival of VIIIth nerve fibers in NM. By E10, immunoreactivity for SV2 was heavily concentrated in the dorsal and ventral neuropils of NL. Thus, extensive pathfinding and morphological rearrangement of central auditory nuclei occurs well before the arrival of cochlear afferents. Our results suggest that NM neurons may play a central role in formation of tonotopic connections in the auditory system.

  8. Modelling hierarchical and modular complex networks: division and independence

    Science.gov (United States)

    Kim, D.-H.; Rodgers, G. J.; Kahng, B.; Kim, D.

    2005-06-01

    We introduce a growing network model which generates both modular and hierarchical structure in a self-organized way. To this end, we modify the Barabási-Albert model into the one evolving under the principles of division and independence as well as growth and preferential attachment (PA). A newly added vertex chooses one of the modules composed of existing vertices, and attaches edges to vertices belonging to that module following the PA rule. When the module size reaches a proper size, the module is divided into two, and a new module is created. The karate club network studied by Zachary is a simple version of the current model. We find that the model can reproduce both modular and hierarchical properties, characterized by the hierarchical clustering function of a vertex with degree k, C(k), being in good agreement with empirical measurements for real-world networks.

  9. Liquid phase epitaxial growth of heterostructured hierarchical MOF thin films

    KAUST Repository

    Chernikova, Valeriya

    2017-05-10

    Precise control of epitaxial growth of MOF-on-MOF thin films, for ordered hierarchical tbo-type structures is demonstrated. The heterostructured MOF thin film was fabricated by successful sequential deposition of layers from two different MOFs. The 2-periodic layers, edge-transitive 4,4-square lattices regarded as supermolecular building layers, were commendably cross-linked using a combination of inorganic/organic and organic pillars.

  10. Hierarchical honeycomb auxetic metamaterials.

    Science.gov (United States)

    Mousanezhad, Davood; Babaee, Sahab; Ebrahimi, Hamid; Ghosh, Ranajay; Hamouda, Abdelmagid Salem; Bertoldi, Katia; Vaziri, Ashkan

    2015-12-16

    Most conventional materials expand in transverse directions when they are compressed uniaxially resulting in the familiar positive Poisson's ratio. Here we develop a new class of two dimensional (2D) metamaterials with negative Poisson's ratio that contract in transverse directions under uniaxial compressive loads leading to auxeticity. This is achieved through mechanical instabilities (i.e., buckling) introduced by structural hierarchy and retained over a wide range of applied compression. This unusual behavior is demonstrated experimentally and analyzed computationally. The work provides new insights into the role of structural organization and hierarchy in designing 2D auxetic metamaterials, and new opportunities for developing energy absorbing materials, tunable membrane filters, and acoustic dampeners.

  11. One-Step Conversion from Core-Shell Metal-Organic Framework Materials to Cobalt and Nitrogen Codoped Carbon Nanopolyhedra with Hierarchically Porous Structure for Highly Efficient Oxygen Reduction.

    Science.gov (United States)

    Hu, Zhaowen; Zhang, Zhengping; Li, Zhilin; Dou, Meiling; Wang, Feng

    2017-05-17

    Rational design of porous structure is an effective way to fabricate the nonprecious metal electrocatalysts (NPMCs) toward oxygen reduction reaction (ORR) with high activity comparable or even superior to Pt-based electrocatalysts. Herein, we demonstrate a facile synthetic route to fabricate cobalt and nitrogen codoped carbon nanopolyhedra with hierarchically porous structure (Co,N-HCNP) by one-step carbonization of core-shell structured ZIF-8@ZIF-67 crystals. The resultant Co,N-HCNP electrocatalyst possesses a unique hierarchically micro/mesoporous structure with internal micropores and external mesopores, of which sufficient exposure and accessibility of ORR active sites can be achieved due to the large specific surface area and efficient transport pathway. More importantly, the existence of ZIF-8 core in the core-shell structured ZIF-8@ZIF-67 can promote the homogeneous pyrolysis of ZIF-67 shell, leading to a uniform distribution of Co-Nx active sites for Co,N-HCNP. As a result, the well-designed Co,N-HCNP electrocatalyst exhibits remarkable ORR activity with a high onset potential comparable to the commercial Pt/C, a half-wave potential of 0.855 V (9 mV more positive than that of Pt/C), and a kinetic current density of 63.84 mA cm(-2) at 0.8 V (2.3-fold enhancement compared with that of Pt/C) in alkaline electrolyte. Furthermore, the Co,N-HCNP electrocatalyst also presents outstanding electrochemical durability and methanol tolerance in comparison with Pt/C. The unique hierarchically porous structure of Co,N-HCNP achieved in this work provides a new insight into the design and synthesis of nanoarchitecture with targeted pore structure and opens a new avenue for the synthesis of highly efficient NPMCs for ORR.

  12. 3D Printing of Hierarchical Silk Fibroin Structures.

    Science.gov (United States)

    Sommer, Marianne R; Schaffner, Manuel; Carnelli, Davide; Studart, André R

    2016-12-21

    Like many other natural materials, silk is hierarchically structured from the amino acid level up to the cocoon or spider web macroscopic structures. Despite being used industrially in a number of applications, hierarchically structured silk fibroin objects with a similar degree of architectural control as in natural structures have not been produced yet due to limitations in fabrication processes. In a combined top-down and bottom-up approach, we exploit the freedom in macroscopic design offered by 3D printing and the template-guided assembly of ink building blocks at the meso- and nanolevel to fabricate hierarchical silk porous materials with unprecedented structural control. Pores with tunable sizes in the range 40-350 μm are generated by adding sacrificial organic microparticles as templates to a silk fibroin-based ink. Commercially available wax particles or monodisperse polycaprolactone made by microfluidics can be used as microparticle templates. Since closed pores are generated after template removal, an ultrasonication treatment can optionally be used to achieve open porosity. Such pore templating particles can be further modified with nanoparticles to create a hierarchical template that results in porous structures with a defined nanotopography on the pore walls. The hierarchically porous silk structures obtained with this processing technique can potentially be utilized in various application fields from structural materials to thermal insulation to tissue engineering scaffolds.

  13. The auditory brainstem is a barometer of rapid auditory learning.

    Science.gov (United States)

    Skoe, E; Krizman, J; Spitzer, E; Kraus, N

    2013-07-23

    To capture patterns in the environment, neurons in the auditory brainstem rapidly alter their firing based on the statistical properties of the soundscape. How this neural sensitivity relates to behavior is unclear. We tackled this question by combining neural and behavioral measures of statistical learning, a general-purpose learning mechanism governing many complex behaviors including language acquisition. We recorded complex auditory brainstem responses (cABRs) while human adults implicitly learned to segment patterns embedded in an uninterrupted sound sequence based on their statistical characteristics. The brainstem's sensitivity to statistical structure was measured as the change in the cABR between a patterned and a pseudo-randomized sequence composed from the same set of sounds but differing in their sound-to-sound probabilities. Using this methodology, we provide the first demonstration that behavioral-indices of rapid learning relate to individual differences in brainstem physiology. We found that neural sensitivity to statistical structure manifested along a continuum, from adaptation to enhancement, where cABR enhancement (patterned>pseudo-random) tracked with greater rapid statistical learning than adaptation. Short- and long-term auditory experiences (days to years) are known to promote brainstem plasticity and here we provide a conceptual advance by showing that the brainstem is also integral to rapid learning occurring over minutes.

  14. Spectral organization of the human lateral superior temporal gyrus revealed by intracranial recordings.

    Science.gov (United States)

    Nourski, Kirill V; Steinschneider, Mitchell; Oya, Hiroyuki; Kawasaki, Hiroto; Jones, Robert D; Howard, Matthew A

    2014-02-01

    The place of the posterolateral superior temporal (PLST) gyrus within the hierarchical organization of the human auditory cortex is unknown. Understanding how PLST processes spectral information is imperative for its functional characterization. Pure-tone stimuli were presented to subjects undergoing invasive monitoring for refractory epilepsy. Recordings were made using high-density subdural grid electrodes. Pure tones elicited robust high gamma event-related band power responses along a portion of PLST adjacent to the transverse temporal sulcus (TTS). Responses were frequency selective, though typically broadly tuned. In several subjects, mirror-image response patterns around a low-frequency center were observed, but typically, more complex and distributed patterns were seen. Frequency selectivity was greatest early in the response. Classification analysis using a sparse logistic regression algorithm yielded above-chance accuracy in all subjects. Classifier performance typically peaked at 100-150 ms after stimulus onset, was comparable for the left and right hemisphere cases, and was stable across stimulus intensities. Results demonstrate that representations of spectral information within PLST are temporally dynamic and contain sufficient information for accurate discrimination of tone frequencies. PLST adjacent to the TTS appears to be an early stage in the hierarchy of cortical auditory processing. Pure-tone response patterns may aid auditory field identification.

  15. Adaptation in the auditory system: an overview

    Directory of Open Access Journals (Sweden)

    David ePérez-González

    2014-02-01

    Full Text Available The early stages of the auditory system need to preserve the timing information of sounds in order to extract the basic features of acoustic stimuli. At the same time, different processes of neuronal adaptation occur at several levels to further process the auditory information. For instance, auditory nerve fiber responses already experience adaptation of their firing rates, a type of response that can be found in many other auditory nuclei and may be useful for emphasizing the onset of the stimuli. However, it is at higher levels in the auditory hierarchy where more sophisticated types of neuronal processing take place. For example, stimulus-specific adaptation, where neurons show adaptation to frequent, repetitive stimuli, but maintain their responsiveness to stimuli with different physical characteristics, thus representing a distinct kind of processing that may play a role in change and deviance detection. In the auditory cortex, adaptation takes more elaborate forms, and contributes to the processing of complex sequences, auditory scene analysis and attention. Here we review the multiple types of adaptation that occur in the auditory system, which are part of the pool of resources that the neurons employ to process the auditory scene, and are critical to a proper understanding of the neuronal mechanisms that govern auditory perception.

  16. Auditory adaptation improves tactile frequency perception.

    Science.gov (United States)

    Crommett, Lexi E; Pérez-Bellido, Alexis; Yau, Jeffrey M

    2017-01-11

    Our ability to process temporal frequency information by touch underlies our capacity to perceive and discriminate surface textures. Auditory signals, which also provide extensive temporal frequency information, can systematically alter the perception of vibrations on the hand. How auditory signals shape tactile processing is unclear: perceptual interactions between contemporaneous sounds and vibrations are consistent with multiple neural mechanisms. Here we used a crossmodal adaptation paradigm, which separated auditory and tactile stimulation in time, to test the hypothesis that tactile frequency perception depends on neural circuits that also process auditory frequency. We reasoned that auditory adaptation effects would transfer to touch only if signals from both senses converge on common representations. We found that auditory adaptation can improve tactile frequency discrimination thresholds. This occurred only when adaptor and test frequencies overlapped. In contrast, auditory adaptation did not influence tactile intensity judgments. Thus, auditory adaptation enhances touch in a frequency- and feature-specific manner. A simple network model in which tactile frequency information is decoded from sensory neurons that are susceptible to auditory adaptation recapitulates these behavioral results. Our results imply that the neural circuits supporting tactile frequency perception also process auditory signals. This finding is consistent with the notion of supramodal operators performing canonical operations, like temporal frequency processing, regardless of input modality.

  17. Auditory Dysfunction in Patients with Cerebrovascular Disease

    Directory of Open Access Journals (Sweden)

    Sadaharu Tabuchi

    2014-01-01

    Full Text Available Auditory dysfunction is a common clinical symptom that can induce profound effects on the quality of life of those affected. Cerebrovascular disease (CVD is the most prevalent neurological disorder today, but it has generally been considered a rare cause of auditory dysfunction. However, a substantial proportion of patients with stroke might have auditory dysfunction that has been underestimated due to difficulties with evaluation. The present study reviews relationships between auditory dysfunction and types of CVD including cerebral infarction, intracerebral hemorrhage, subarachnoid hemorrhage, cerebrovascular malformation, moyamoya disease, and superficial siderosis. Recent advances in the etiology, anatomy, and strategies to diagnose and treat these conditions are described. The numbers of patients with CVD accompanied by auditory dysfunction will increase as the population ages. Cerebrovascular diseases often include the auditory system, resulting in various types of auditory dysfunctions, such as unilateral or bilateral deafness, cortical deafness, pure word deafness, auditory agnosia, and auditory hallucinations, some of which are subtle and can only be detected by precise psychoacoustic and electrophysiological testing. The contribution of CVD to auditory dysfunction needs to be understood because CVD can be fatal if overlooked.

  18. Multiscale mapping of frequency sweep rate in mouse auditory cortex.

    Science.gov (United States)

    Issa, John B; Haeffele, Benjamin D; Young, Eric D; Yue, David T

    2017-02-01

    Functional organization is a key feature of the neocortex that often guides studies of sensory processing, development, and plasticity. Tonotopy, which arises from the transduction properties of the cochlea, is the most widely studied organizational feature in auditory cortex; however, in order to process complex sounds, cortical regions are likely specialized for higher order features. Here, motivated by the prevalence of frequency modulations in mouse ultrasonic vocalizations and aided by the use of a multiscale imaging approach, we uncover a functional organization across the extent of auditory cortex for the rate of frequency modulated (FM) sweeps. In particular, using two-photon Ca(2+) imaging of layer 2/3 neurons, we identify a tone-insensitive region at the border of AI and AAF. This central sweep region behaves fundamentally differently from nearby neurons in AI and AII, responding preferentially to fast FM sweeps but not to tones or bandlimited noise. Together these findings define a second dimension of organization in the mouse auditory cortex for sweep rate complementary to that of tone frequency.

  19. A Hierarchical Bayesian Model for Crowd Emotions

    Science.gov (United States)

    Urizar, Oscar J.; Baig, Mirza S.; Barakova, Emilia I.; Regazzoni, Carlo S.; Marcenaro, Lucio; Rauterberg, Matthias

    2016-01-01

    Estimation of emotions is an essential aspect in developing intelligent systems intended for crowded environments. However, emotion estimation in crowds remains a challenging problem due to the complexity in which human emotions are manifested and the capability of a system to perceive them in such conditions. This paper proposes a hierarchical Bayesian model to learn in unsupervised manner the behavior of individuals and of the crowd as a single entity, and explore the relation between behavior and emotions to infer emotional states. Information about the motion patterns of individuals are described using a self-organizing map, and a hierarchical Bayesian network builds probabilistic models to identify behaviors and infer the emotional state of individuals and the crowd. This model is trained and tested using data produced from simulated scenarios that resemble real-life environments. The conducted experiments tested the efficiency of our method to learn, detect and associate behaviors with emotional states yielding accuracy levels of 74% for individuals and 81% for the crowd, similar in performance with existing methods for pedestrian behavior detection but with novel concepts regarding the analysis of crowds. PMID:27458366

  20. Electrostimulation mapping of comprehension of auditory and visual words.

    Science.gov (United States)

    Roux, Franck-Emmanuel; Miskin, Krasimir; Durand, Jean-Baptiste; Sacko, Oumar; Réhault, Emilie; Tanova, Rositsa; Démonet, Jean-François

    2015-10-01

    In order to spare functional areas during the removal of brain tumours, electrical stimulation mapping was used in 90 patients (77 in the left hemisphere and 13 in the right; 2754 cortical sites tested). Language functions were studied with a special focus on comprehension of auditory and visual words and the semantic system. In addition to naming, patients were asked to perform pointing tasks from auditory and visual stimuli (using sets of 4 different images controlled for familiarity), and also auditory object (sound recognition) and Token test tasks. Ninety-two auditory comprehension interference sites were observed. We found that the process of auditory comprehension involved a few, fine-grained, sub-centimetre cortical territories. Early stages of speech comprehension seem to relate to two posterior regions in the left superior temporal gyrus. Downstream lexical-semantic speech processing and sound analysis involved 2 pathways, along the anterior part of the left superior temporal gyrus, and posteriorly around the supramarginal and middle temporal gyri. Electrostimulation experimentally dissociated perceptual consciousness attached to speech comprehension. The initial word discrimination process can be considered as an "automatic" stage, the attention feedback not being impaired by stimulation as would be the case at the lexical-semantic stage. Multimodal organization of the superior temporal gyrus was also detected since some neurones could be involved in comprehension of visual material and naming. These findings demonstrate a fine graded, sub-centimetre, cortical representation of speech comprehension processing mainly in the left superior temporal gyrus and are in line with those described in dual stream models of language comprehension processing.

  1. Sacculo-collic pathway dysfunction accompanying auditory neuropathy.

    Science.gov (United States)

    Sheykholeslami, Kianoush; Schmerber, Sébastien; Habiby Kermany, Mohammad; Kaga, Kimitaka

    2005-07-01

    In a patient with bilateral auditory neuropathy (AN), the vestibular-evoked myogenic potential (VEMP) was probably absent because of a neuropathy involving the inferior vestibular nerve and/or its end organ, the saccule. Our result can therefore be interpreted as a concomitant unilateral sacculo-collic neuropathy. We suggest the use of more precise terms to characterize AN patients with involvement of different parts of the inner ear and its innervations. We encourage detailed vestibular assessment in patients with AN in order to assess the co-existence of any symptomatic or asymptomatic vestibular disorder. Information such as that provided in this report will be valuable for clinicians caring for this group of patients. AN is a disorder characterized by the absence or severe impairment of auditory brainstem responses in the presence of normal cochlear outer hair cell function as revealed by otoacoustic emissions (OAEs) and/or electrocochleography (ECoG). A variety of processes and etiologies are thought to be involved in its pathophysiology. In most literature reports the auditory profile of patients with AN is discussed. However, the extent of vestibular involvement, especially that involving the saccule, is not known. We performed vestibular tests to assess the status of the saccule in a patient with AN. One patient with AN was studied. The patient was a right-handed 21-year-old female with chief complaints of hearing loss and speech perception difficulty. The auditory test results were consistent with the diagnosis of AN, i.e. absent auditory brainstem responses, moderate hearing loss, an inappropriately profound speech discrimination score and the presence of OAEs and measurable cochlear microphonics on ECoG. On neurological examination, gait and balance tests were normal. Ice-water caloric testing induced a sensation of dizziness in both ears. Short tone-burst VEMPs showed no response on left-ear stimulation and a biphasic response with normal latency and

  2. Hierarchical structuring of liquid crystal polymer-Laponite hybrid materials.

    Science.gov (United States)

    Tritschler, Ulrich; Zlotnikov, Igor; Zaslansky, Paul; Aichmayer, Barbara; Fratzl, Peter; Schlaad, Helmut; Cölfen, Helmut

    2013-09-03

    Biomimetic organic-inorganic composite materials were fabricated via one-step self-organization on three hierarchical levels. The organic component was a polyoxazoline with pendent cholesteryl and carboxyl (N-Boc-protected amino acid) side chains that was able to form a chiral nematic lyotropic phase and bind to positively charged inorganic faces of Laponite. The Laponite particles formed a mesocrystalline arrangement within the liquid-crystal (LC) polymer phase upon shearing a viscous dispersion of Laponite nanoparticles and LC polymer in DMF. Complementary analytical and mechanical characterization techniques (AUC, POM, TEM, SEM, SAXS, μCT, and nanoindentation) covering the millimeter, micrometer, and nanometer length scales reveal the hierarchical structures and properties of the composite materials consisting of different ratios of Laponite nanoparticles and liquid-crystalline polymer.

  3. Auditory Motion Elicits a Visual Motion Aftereffect

    Directory of Open Access Journals (Sweden)

    Christopher C. Berger

    2016-12-01

    Full Text Available The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

  4. Functional maps of human auditory cortex: effects of acoustic features and attention.

    Directory of Open Access Journals (Sweden)

    David L Woods

    Full Text Available BACKGROUND: While human auditory cortex is known to contain tonotopically organized auditory cortical fields (ACFs, little is known about how processing in these fields is modulated by other acoustic features or by attention. METHODOLOGY/PRINCIPAL FINDINGS: We used functional magnetic resonance imaging (fMRI and population-based cortical surface analysis to characterize the tonotopic organization of human auditory cortex and analyze the influence of tone intensity, ear of delivery, scanner background noise, and intermodal selective attention on auditory cortex activations. Medial auditory cortex surrounding Heschl's gyrus showed large sensory (unattended activations with two mirror-symmetric tonotopic fields similar to those observed in non-human primates. Sensory responses in medial regions had symmetrical distributions with respect to the left and right hemispheres, were enlarged for tones of increased intensity, and were enhanced when sparse image acquisition reduced scanner acoustic noise. Spatial distribution analysis suggested that changes in tone intensity shifted activation within isofrequency bands. Activations to monaural tones were enhanced over the hemisphere contralateral to stimulation, where they produced activations similar to those produced by binaural sounds. Lateral regions of auditory cortex showed small sensory responses that were larger in the right than left hemisphere, lacked tonotopic organization, and were uninfluenced by acoustic parameters. Sensory responses in both medial and lateral auditory cortex decreased in magnitude throughout stimulus blocks. Attention-related modulations (ARMs were larger in lateral than medial regions of auditory cortex and appeared to arise primarily in belt and parabelt auditory fields. ARMs lacked tonotopic organization, were unaffected by acoustic parameters, and had distributions that were distinct from those of sensory responses. Unlike the gradual adaptation seen for sensory responses

  5. Auditory evoked potentials and multiple sclerosis

    OpenAIRE

    Carla Gentile Matas; Sandro Luiz de Andrade Matas; Caroline Rondina Salzano de Oliveira; Isabela Crivellaro Gonçalves

    2010-01-01

    Multiple sclerosis (MS) is an inflammatory, demyelinating disease that can affect several areas of the central nervous system. Damage along the auditory pathway can alter its integrity significantly. Therefore, it is important to investigate the auditory pathway, from the brainstem to the cortex, in individuals with MS. OBJECTIVE: The aim of this study was to characterize auditory evoked potentials in adults with MS of the remittent-recurrent type. METHOD: The study comprised 25 individuals w...

  6. Speech distortion measure based on auditory properties

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo; HU Xiulin; ZHANG Yunyu; ZHU Yaoting

    2000-01-01

    The Perceptual Spectrum Distortion (PSD), based on auditory properties of human being, is presented to measure speech distortion. The PSD measure calculates the speech distortion distance by simulating the auditory properties of human being and converting short-time speech power spectrum to auditory perceptual spectrum. Preliminary simulative experiments in comparison with the Itakura measure have been done. The results show that the PSD measure is a perferable speech distortion measure and more consistent with subjective assessment of speech quality.

  7. Hierarchical Prisoner's Dilemma in Hierarchical Public-Goods Game

    CERN Document Server

    Fujimoto, Yuma; Kaneko, Kunihiko

    2016-01-01

    The dilemma in cooperation is one of the major concerns in game theory. In a public-goods game, each individual pays a cost for cooperation, or to prevent defection, and receives a reward from the collected cost in a group. Thus, defection is beneficial for each individual, while cooperation is beneficial for the group. Now, groups (say, countries) consisting of individual players also play games. To study such a multi-level game, we introduce a hierarchical public-goods (HPG) game in which two groups compete for finite resources by utilizing costs collected from individuals in each group. Analyzing this HPG game, we found a hierarchical prisoner's dilemma, in which groups choose the defection policy (say, armaments) as a Nash strategy to optimize each group's benefit, while cooperation optimizes the total benefit. On the other hand, for each individual within a group, refusing to pay the cost (say, tax) is a Nash strategy, which turns to be a cooperation policy for the group, thus leading to a hierarchical d...

  8. Auditory Training and Its Effects upon the Auditory Discrimination and Reading Readiness of Kindergarten Children.

    Science.gov (United States)

    Cullen, Minga Mustard

    The purpose of this investigation was to evaluate the effects of a systematic auditory training program on the auditory discrimination ability and reading readiness of 55 white, middle/upper middle class kindergarten students. Following pretesting with the "Wepman Auditory Discrimination Test,""The Clymer-Barrett Prereading Battery," and the…

  9. Effects of Methylphenidate (Ritalin) on Auditory Performance in Children with Attention and Auditory Processing Disorders.

    Science.gov (United States)

    Tillery, Kim L.; Katz, Jack; Keller, Warren D.

    2000-01-01

    A double-blind, placebo-controlled study examined effects of methylphenidate (Ritalin) on auditory processing in 32 children with both attention deficit hyperactivity disorder and central auditory processing (CAP) disorder. Analyses revealed that Ritalin did not have a significant effect on any of the central auditory processing measures, although…

  10. Central auditory function of deafness genes.

    Science.gov (United States)

    Willaredt, Marc A; Ebbers, Lena; Nothwang, Hans Gerd

    2014-06-01

    The highly variable benefit of hearing devices is a serious challenge in auditory rehabilitation. Various factors contribute to this phenomenon such as the diversity in ear defects, the different extent of auditory nerve hypoplasia, the age of intervention, and cognitive abilities. Recent analyses indicate that, in addition, central auditory functions of deafness genes have to be considered in this context. Since reduced neuronal activity acts as the common denominator in deafness, it is widely assumed that peripheral deafness influences development and function of the central auditory system in a stereotypical manner. However, functional characterization of transgenic mice with mutated deafness genes demonstrated gene-specific abnormalities in the central auditory system as well. A frequent function of deafness genes in the central auditory system is supported by a genome-wide expression study that revealed significant enrichment of these genes in the transcriptome of the auditory brainstem compared to the entire brain. Here, we will summarize current knowledge of the diverse central auditory functions of deafness genes. We furthermore propose the intimately interwoven gene regulatory networks governing development of the otic placode and the hindbrain as a mechanistic explanation for the widespread expression of these genes beyond the cochlea. We conclude that better knowledge of central auditory dysfunction caused by genetic alterations in deafness genes is required. In combination with improved genetic diagnostics becoming currently available through novel sequencing technologies, this information will likely contribute to better outcome prediction of hearing devices.

  11. Fluorocarbon Adsorption in Hierarchical Porous Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Motkuri, Radha K.; Annapureddy, Harsha V.; Vijayakumar, M.; Schaef, Herbert T.; Martin, P F.; McGrail, B. Peter; Dang, Liem X.; Krishna, Rajamani; Thallapally, Praveen K.

    2014-07-09

    The adsorption behavior of a series of fluorocarbon derivatives was examined on a set of microporous metal organic framework (MOF) sorbents and another set of hierarchical mesoporous MOFs. The microporous M-DOBDC (M = Ni, Co) showed a saturation uptake capacity for R12 of over 4 mmol/g at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous MOF MIL-101 showed an exceptionally high uptake capacity reaching over 14 mmol/g at P/Po of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption were found to generally correlate with the polarizability of the refrigerant with R12 > R22 > R13 > R14 > methane. These results suggest the possibility of exploiting MOFs for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling and refrigeration applications.

  12. Intuitionistic fuzzy hierarchical clustering algorithms

    Institute of Scientific and Technical Information of China (English)

    Xu Zeshui

    2009-01-01

    Intuitionistic fuzzy set (IFS) is a set of 2-tuple arguments, each of which is characterized by a mem-bership degree and a nonmembership degree. The generalized form of IFS is interval-valued intuitionistic fuzzy set (IVIFS), whose components are intervals rather than exact numbers. IFSs and IVIFSs have been found to be very useful to describe vagueness and uncertainty. However, it seems that little attention has been focused on the clus-tering analysis of IFSs and IVIFSs. An intuitionistic fuzzy hierarchical algorithm is introduced for clustering IFSs, which is based on the traditional hierarchical clustering procedure, the intuitionistic fuzzy aggregation operator, and the basic distance measures between IFSs: the Hamming distance, normalized Hamming, weighted Hamming, the Euclidean distance, the normalized Euclidean distance, and the weighted Euclidean distance. Subsequently, the algorithm is extended for clustering IVIFSs. Finally the algorithm and its extended form are applied to the classifications of building materials and enterprises respectively.

  13. Hierarchical Formation of Galactic Clusters

    CERN Document Server

    Elmegreen, B G

    2006-01-01

    Young stellar groupings and clusters have hierarchical patterns ranging from flocculent spiral arms and star complexes on the largest scale to OB associations, OB subgroups, small loose groups, clusters and cluster subclumps on the smallest scales. There is no obvious transition in morphology at the cluster boundary, suggesting that clusters are only the inner parts of the hierarchy where stars have had enough time to mix. The power-law cluster mass function follows from this hierarchical structure: n(M_cl) M_cl^-b for b~2. This value of b is independently required by the observation that the summed IMFs from many clusters in a galaxy equals approximately the IMF of each cluster.

  14. Hierarchical matrices algorithms and analysis

    CERN Document Server

    Hackbusch, Wolfgang

    2015-01-01

    This self-contained monograph presents matrix algorithms and their analysis. The new technique enables not only the solution of linear systems but also the approximation of matrix functions, e.g., the matrix exponential. Other applications include the solution of matrix equations, e.g., the Lyapunov or Riccati equation. The required mathematical background can be found in the appendix. The numerical treatment of fully populated large-scale matrices is usually rather costly. However, the technique of hierarchical matrices makes it possible to store matrices and to perform matrix operations approximately with almost linear cost and a controllable degree of approximation error. For important classes of matrices, the computational cost increases only logarithmically with the approximation error. The operations provided include the matrix inversion and LU decomposition. Since large-scale linear algebra problems are standard in scientific computing, the subject of hierarchical matrices is of interest to scientists ...

  15. Hierarchical Cont-Bouchaud model

    CERN Document Server

    Paluch, Robert; Holyst, Janusz A

    2015-01-01

    We extend the well-known Cont-Bouchaud model to include a hierarchical topology of agent's interactions. The influence of hierarchy on system dynamics is investigated by two models. The first one is based on a multi-level, nested Erdos-Renyi random graph and individual decisions by agents according to Potts dynamics. This approach does not lead to a broad return distribution outside a parameter regime close to the original Cont-Bouchaud model. In the second model we introduce a limited hierarchical Erdos-Renyi graph, where merging of clusters at a level h+1 involves only clusters that have merged at the previous level h and we use the original Cont-Bouchaud agent dynamics on resulting clusters. The second model leads to a heavy-tail distribution of cluster sizes and relative price changes in a wide range of connection densities, not only close to the percolation threshold.

  16. Hierarchical Clustering and Active Galaxies

    CERN Document Server

    Hatziminaoglou, E; Manrique, A

    2000-01-01

    The growth of Super Massive Black Holes and the parallel development of activity in galactic nuclei are implemented in an analytic code of hierarchical clustering. The evolution of the luminosity function of quasars and AGN will be computed with special attention paid to the connection between quasars and Seyfert galaxies. One of the major interests of the model is the parallel study of quasar formation and evolution and the History of Star Formation.

  17. Hybrid and hierarchical composite materials

    CERN Document Server

    Kim, Chang-Soo; Sano, Tomoko

    2015-01-01

    This book addresses a broad spectrum of areas in both hybrid materials and hierarchical composites, including recent development of processing technologies, structural designs, modern computer simulation techniques, and the relationships between the processing-structure-property-performance. Each topic is introduced at length with numerous  and detailed examples and over 150 illustrations.   In addition, the authors present a method of categorizing these materials, so that representative examples of all material classes are discussed.

  18. Differences in neurogenesis differentiate between core and shell regions of auditory nuclei in the turtle (Pelodiscus sinensis): evolutionary implications.

    Science.gov (United States)

    Zeng, Shao-Ju; Xi, Chao; Zhang, Xin-Wen; Zuo, Ming-Xue

    2007-01-01

    There is a clear core-versus-shell distinction in cytoarchitecture, electrophysiological properties and neural connections in the mesencephalic and diencephalic auditory nuclei of amniotes. Determining whether the embryogenesis of auditory nuclei shows a similar organization is helpful for further understanding the constituent organization and evolution of auditory nuclei. Therefore in the present study, we injected [(3)H]-thymidine into turtle embryos (Pelodiscus sinensis) at various stages of development. Upon hatching, [(3)H]-thymidine labeling was examined in both the core and shell auditory regions in the midbrain, diencephalon and dorsal ventricular ridge. Met-enkephalin and substance P immunohistochemistry was used to distinguish the core and shell regions. In the mesencephalic auditory nucleus, the occurrence of heavily labeled neurons in the nucleus centralis of the torus semicircularis reached its peak at embryonic day 9, one day later than the surrounding shell. In the diencephalic auditory nucleus, the production of heavily labeled neurons in the central region of the reuniens (Re) was highest at embryonic day (E) 8, one day later than that in the shell region of reuniens. In the region of the dorsal ventricular ridge that received inputs from the central region of Re, the appearance of heavily labeled neurons also reached a peak one day later than that in the area receiving inputs from the shell region of reuniens. Thus, there is a core-versus-shell organization of neuronal generation in reptilian auditory areas. Copyright (c) 2007 S. Karger AG, Basel.

  19. Towards an auditory account of speech rhythm: application of a model of the auditory 'primal sketch' to two multi-language corpora.

    Science.gov (United States)

    Lee, Christopher S; Todd, Neil P McAngus

    2004-10-01

    The world's languages display important differences in their rhythmic organization; most particularly, different languages seem to privilege different phonological units (mora, syllable, or stress foot) as their basic rhythmic unit. There is now considerable evidence that such differences have important consequences for crucial aspects of language acquisition and processing. Several questions remain, however, as to what exactly characterizes the rhythmic differences, how they are manifested at an auditory/acoustic level and how listeners, whether adult native speakers or young infants, process rhythmic information. In this paper it is proposed that the crucial determinant of rhythmic organization is the variability in the auditory prominence of phonetic events. In order to test this auditory prominence hypothesis, an auditory model is run on two multi-language data-sets, the first consisting of matched pairs of English and French sentences, and the second consisting of French, Italian, English and Dutch sentences. The model is based on a theory of the auditory primal sketch, and generates a primitive representation of an acoustic signal (the rhythmogram) which yields a crude segmentation of the speech signal and assigns prominence values to the obtained sequence of events. Its performance is compared with that of several recently proposed phonetic measures of vocalic and consonantal variability.

  20. Rodent Auditory Perception: Critical Band Limitations and Plasticity

    Science.gov (United States)

    King, Julia; Insanally, Michele; Jin, Menghan; Martins, Ana Raquel O.; D'amour, James A.; Froemke, Robert C.

    2015-01-01

    What do animals hear? While it remains challenging to adequately assess sensory perception in animal models, it is important to determine perceptual abilities in model systems to understand how physiological processes and plasticity relate to perception, learning, and cognition. Here we discuss hearing in rodents, reviewing previous and recent behavioral experiments querying acoustic perception in rats and mice, and examining the relation between behavioral data and electrophysiological recordings from the central auditory system. We focus on measurements of critical bands, which are psychoacoustic phenomena that seem to have a neural basis in the functional organization of the cochlea and the inferior colliculus. We then discuss how behavioral training, brain stimulation, and neuropathology impact auditory processing and perception. PMID:25827498

  1. Auditory hallucinations in nonverbal quadriplegics.

    Science.gov (United States)

    Hamilton, J

    1985-11-01

    When a system for communicating with nonverbal, quadriplegic, institutionalized residents was developed, it was discovered that many were experiencing auditory hallucinations. Nine cases are presented in this study. The "voices" described have many similar characteristics, the primary one being that they give authoritarian commands that tell the residents how to behave and to which the residents feel compelled to respond. Both the relationship of this phenomenon to the theoretical work of Julian Jaynes and its effect on the lives of the residents are discussed.

  2. Autosomal recessive hereditary auditory neuropathy

    Institute of Scientific and Technical Information of China (English)

    王秋菊; 顾瑞; 曹菊阳

    2003-01-01

    Objectives: Auditory neuropathy (AN) is a sensorineural hearing disorder characterized by absent or abnormal auditory brainstem responses (ABRs) and normal cochlear outer hair cell function as measured by otoacoustic emissions (OAEs). Many risk factors are thought to be involved in its etiology and pathophysiology. Three Chinese pedigrees with familial AN are presented herein to demonstrate involvement of genetic factors in AN etiology. Methods: Probands of the above - mentioned pedigrees, who had been diagnosed with AN, were evaluated and followed up in the Department of Otolaryngology Head and Neck Surgery, China PLA General Hospital. Their family members were studied and the pedigree diagrams were established. History of illness, physical examination,pure tone audiometry, acoustic reflex, ABRs and transient evoked and distortion- product otoacoustic emissions (TEOAEs and DPOAEs) were obtained from members of these families. DPOAE changes under the influence of contralateral sound stimuli were observed by presenting a set of continuous white noise to the non - recording ear to exam the function of auditory efferent system. Some subjects received vestibular caloric test, computed tomography (CT)scan of the temporal bone and electrocardiography (ECG) to exclude other possible neuropathy disorders. Results: In most affected subjects, hearing loss of various degrees and speech discrimination difficulties started at 10 to16 years of age. Their audiological evaluation showed absence of acoustic reflex and ABRs. As expected in AN, these subjects exhibited near normal cochlear outer hair cell function as shown in TEOAE & DPOAE recordings. Pure- tone audiometry revealed hearing loss ranging from mild to severe in these patients. Autosomal recessive inheritance patterns were observed in the three families. In Pedigree Ⅰ and Ⅱ, two affected brothers were found respectively, while in pedigree Ⅲ, 2 sisters were affected. All the patients were otherwise normal without

  3. Narrow, duplicated internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

    2003-05-01

    A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

  4. Further Evidence of Auditory Extinction in Aphasia

    Science.gov (United States)

    Marshall, Rebecca Shisler; Basilakos, Alexandra; Love-Myers, Kim

    2013-01-01

    Purpose: Preliminary research ( Shisler, 2005) suggests that auditory extinction in individuals with aphasia (IWA) may be connected to binding and attention. In this study, the authors expanded on previous findings on auditory extinction to determine the source of extinction deficits in IWA. Method: Seventeen IWA (M[subscript age] = 53.19 years)…

  5. Primary Auditory Cortex Regulates Threat Memory Specificity

    Science.gov (United States)

    Wigestrand, Mattis B.; Schiff, Hillary C.; Fyhn, Marianne; LeDoux, Joseph E.; Sears, Robert M.

    2017-01-01

    Distinguishing threatening from nonthreatening stimuli is essential for survival and stimulus generalization is a hallmark of anxiety disorders. While auditory threat learning produces long-lasting plasticity in primary auditory cortex (Au1), it is not clear whether such Au1 plasticity regulates memory specificity or generalization. We used…

  6. Mapping tonotopy in human auditory cortex

    NARCIS (Netherlands)

    van Dijk, Pim; Langers, Dave R M; Moore, BCJ; Patterson, RD; Winter, IM; Carlyon, RP; Gockel, HE

    2013-01-01

    Tonotopy is arguably the most prominent organizational principle in the auditory pathway. Nevertheless, the layout of tonotopic maps in humans is still debated. We present neuroimaging data that robustly identify multiple tonotopic maps in the bilateral auditory cortex. In contrast with some earlier

  7. Auditory Processing Disorder and Foreign Language Acquisition

    Science.gov (United States)

    Veselovska, Ganna

    2015-01-01

    This article aims at exploring various strategies for coping with the auditory processing disorder in the light of foreign language acquisition. The techniques relevant to dealing with the auditory processing disorder can be attributed to environmental and compensatory approaches. The environmental one involves actions directed at creating a…

  8. Primary Auditory Cortex Regulates Threat Memory Specificity

    Science.gov (United States)

    Wigestrand, Mattis B.; Schiff, Hillary C.; Fyhn, Marianne; LeDoux, Joseph E.; Sears, Robert M.

    2017-01-01

    Distinguishing threatening from nonthreatening stimuli is essential for survival and stimulus generalization is a hallmark of anxiety disorders. While auditory threat learning produces long-lasting plasticity in primary auditory cortex (Au1), it is not clear whether such Au1 plasticity regulates memory specificity or generalization. We used…

  9. Passive auditory stimulation improves vision in hemianopia.

    Directory of Open Access Journals (Sweden)

    Jörg Lewald

    Full Text Available UNLABELLED: Techniques employed in rehabilitation of visual field disorders such as hemianopia are usually based on either visual or audio-visual stimulation and patients have to perform a training task. Here we present results from a completely different, novel approach that was based on passive unimodal auditory stimulation. Ten patients with either left or right-sided pure hemianopia (without neglect received one hour of unilateral passive auditory stimulation on either their anopic or their intact side by application of repetitive trains of sound pulses emitted simultaneously via two loudspeakers. Immediately before and after passive auditory stimulation as well as after a period of recovery, patients completed a simple visual task requiring detection of light flashes presented along the horizontal plane in total darkness. The results showed that one-time passive auditory stimulation on the side of the blind, but not of the intact, hemifield of patients with hemianopia induced an improvement in visual detections by almost 100% within 30 min after passive auditory stimulation. This enhancement in performance was reversible and was reduced to baseline 1.5 h later. A non-significant trend of a shift of the visual field border toward the blind hemifield was obtained after passive auditory stimulation. These results are compatible with the view that passive auditory stimulation elicited some activation of the residual visual pathways, which are known to be multisensory and may also be sensitive to unimodal auditory stimuli as were used here. TRIAL REGISTRATION: DRKS00003577.

  10. Bilateral duplication of the internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Weon, Young Cheol; Kim, Jae Hyoung; Choi, Sung Kyu [Seoul National University College of Medicine, Department of Radiology, Seoul National University Bundang Hospital, Seongnam-si (Korea); Koo, Ja-Won [Seoul National University College of Medicine, Department of Otolaryngology, Seoul National University Bundang Hospital, Seongnam-si (Korea)

    2007-10-15

    Duplication of the internal auditory canal is an extremely rare temporal bone anomaly that is believed to result from aplasia or hypoplasia of the vestibulocochlear nerve. We report bilateral duplication of the internal auditory canal in a 28-month-old boy with developmental delay and sensorineural hearing loss. (orig.)

  11. Auditory Processing Disorder and Foreign Language Acquisition

    Science.gov (United States)

    Veselovska, Ganna

    2015-01-01

    This article aims at exploring various strategies for coping with the auditory processing disorder in the light of foreign language acquisition. The techniques relevant to dealing with the auditory processing disorder can be attributed to environmental and compensatory approaches. The environmental one involves actions directed at creating a…

  12. Automatic thoracic anatomy segmentation on CT images using hierarchical fuzzy models and registration

    Science.gov (United States)

    Sun, Kaioqiong; Udupa, Jayaram K.; Odhner, Dewey; Tong, Yubing; Torigian, Drew A.

    2014-03-01

    This paper proposes a thoracic anatomy segmentation method based on hierarchical recognition and delineation guided by a built fuzzy model. Labeled binary samples for each organ are registered and aligned into a 3D fuzzy set representing the fuzzy shape model for the organ. The gray intensity distributions of the corresponding regions of the organ in the original image are recorded in the model. The hierarchical relation and mean location relation between different organs are also captured in the model. Following the hierarchical structure and location relation, the fuzzy shape model of different organs is registered to the given target image to achieve object recognition. A fuzzy connected delineation method is then used to obtain the final segmentation result of organs with seed points provided by recognition. The hierarchical structure and location relation integrated in the model provide the initial parameters for registration and make the recognition efficient and robust. The 3D fuzzy model combined with hierarchical affine registration ensures that accurate recognition can be obtained for both non-sparse and sparse organs. The results on real images are presented and shown to be better than a recently reported fuzzy model-based anatomy recognition strategy.

  13. A organização do autoconceito: análise da estrutura hierárquica em adolescentes Self-concept organization: analysis of hierarchical structure in adolescents

    Directory of Open Access Journals (Sweden)

    Francisco Peixoto

    2011-01-01

    Full Text Available Este estudo tem como objectivo principal a análise da estrutura hierárquica do autoconceito em adolescentes e, adicionalmente, a comparação dessa estrutura em alunos com e sem repetência no seu passado escolar. Participaram no estudo 943 alunos portugueses do 7º, 9º e 11º ano de escolaridade, que responderam a uma escala de autoconceito e de auto-estima. Os resultados obtidos sustentam a ideia de uma organização hierárquica do autoconceito e um modelo que subdivide o autoconceito em quatro factores de ordem superior. Os resultados sugerem, ainda, uma associação entre a dimensão comportamento e diferentes dimensões de ordem superior, nomeadamente as duas dimensões do autoconceito académico e o autoconceito social. Os resultados divergem quando tomamos alunos com maior e menor sucesso escolar, justificando maior atenção na investigação e na intervenção a este aspecto.The main goal of this research is to analyze the hierarchical structure of self-concept in adolescents and, additionally, to compare this structure in students who have failed in their academic career and in those who have not. Nine hundred and forty-three Portuguese students from the 7th, 9th and 11th grades participated in the research. They completed self-concept and self-esteem scales. Results support the assertion that self-concept is hierarchically structured, and also support a model that subdivides self-concept into four higher order factors. Results also suggest an association between the behavioral dimension and various different higher order dimensions, namely, the two academic self-concept dimensions and the social self-concept one. However, they show divergences when the structure of self-concept between achievers and underachievers is compared. This aspect needs to be examined with greater attention on future researches and interventions.

  14. The influence of (central auditory processing disorder in speech sound disorders

    Directory of Open Access Journals (Sweden)

    Tatiane Faria Barrozo

    2016-02-01

    Full Text Available ABSTRACT INTRODUCTION: Considering the importance of auditory information for the acquisition and organization of phonological rules, the assessment of (central auditory processing contributes to both the diagnosis and targeting of speech therapy in children with speech sound disorders. OBJECTIVE: To study phonological measures and (central auditory processing of children with speech sound disorder. METHODS: Clinical and experimental study, with 21 subjects with speech sound disorder aged between 7.0 and 9.11 years, divided into two groups according to their (central auditory processing disorder. The assessment comprised tests of phonology, speech inconsistency, and metalinguistic abilities. RESULTS: The group with (central auditory processing disorder demonstrated greater severity of speech sound disorder. The cutoff value obtained for the process density index was the one that best characterized the occurrence of phonological processes for children above 7 years of age. CONCLUSION: The comparison among the tests evaluated between the two groups showed differences in some phonological and metalinguistic abilities. Children with an index value above 0.54 demonstrated strong tendencies towards presenting a (central auditory processing disorder, and this measure was effective to indicate the need for evaluation in children with speech sound disorder.

  15. The influence of (central) auditory processing disorder in speech sound disorders.

    Science.gov (United States)

    Barrozo, Tatiane Faria; Pagan-Neves, Luciana de Oliveira; Vilela, Nadia; Carvallo, Renata Mota Mamede; Wertzner, Haydée Fiszbein

    2016-01-01

    Considering the importance of auditory information for the acquisition and organization of phonological rules, the assessment of (central) auditory processing contributes to both the diagnosis and targeting of speech therapy in children with speech sound disorders. To study phonological measures and (central) auditory processing of children with speech sound disorder. Clinical and experimental study, with 21 subjects with speech sound disorder aged between 7.0 and 9.11 years, divided into two groups according to their (central) auditory processing disorder. The assessment comprised tests of phonology, speech inconsistency, and metalinguistic abilities. The group with (central) auditory processing disorder demonstrated greater severity of speech sound disorder. The cutoff value obtained for the process density index was the one that best characterized the occurrence of phonological processes for children above 7 years of age. The comparison among the tests evaluated between the two groups showed differences in some phonological and metalinguistic abilities. Children with an index value above 0.54 demonstrated strong tendencies towards presenting a (central) auditory processing disorder, and this measure was effective to indicate the need for evaluation in children with speech sound disorder. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  16. Template-Free Fabrication of Bi2WO6 Hierarchical Hollow Microspheres with Visible-Light-Driven Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Yuxue Zhou

    2016-09-01

    Full Text Available Highly hierarchical hollow bismuth tungstate (Bi2WO6 microspheres self-assembled by thin nanoplates have been fabricated via a facile template-free solvothermal route. The possible growth pattern and formation mechanism of hierarchical hollow Bi2WO6 microspheres was investigated. The excellent visible-light-driven photocatalytic performance on rhodamine B (RhB degradation was displayed by hierarchical hollow Bi2WO6 microspheres. Such well-organized hierarchical hollow Bi2WO6 microspheres show potential application in water treatment fields by full use of solar energy.

  17. Speech perception as complex auditory categorization

    Science.gov (United States)

    Holt, Lori L.

    2002-05-01

    Despite a long and rich history of categorization research in cognitive psychology, very little work has addressed the issue of complex auditory category formation. This is especially unfortunate because the general underlying cognitive and perceptual mechanisms that guide auditory category formation are of great importance to understanding speech perception. I will discuss a new methodological approach to examining complex auditory category formation that specifically addresses issues relevant to speech perception. This approach utilizes novel nonspeech sound stimuli to gain full experimental control over listeners' history of experience. As such, the course of learning is readily measurable. Results from this methodology indicate that the structure and formation of auditory categories are a function of the statistical input distributions of sound that listeners hear, aspects of the operating characteristics of the auditory system, and characteristics of the perceptual categorization system. These results have important implications for phonetic acquisition and speech perception.

  18. Hierarchical structure of biological systems: A bioengineering approach

    OpenAIRE

    Alcocer-Cuarón, Carlos; Rivera, Ana L; Castaño, Victor M.

    2013-01-01

    A general theory of biological systems, based on few fundamental propositions, allows a generalization of both Wierner and Berthalanffy approaches to theoretical biology. Here, a biological system is defined as a set of self-organized, differentiated elements that interact pair-wise through various networks and media, isolated from other sets by boundaries. Their relation to other systems can be described as a closed loop in a steady-state, which leads to a hierarchical structure and function...

  19. Changes in auditory perceptions and cortex resulting from hearing recovery after extended congenital unilateral hearing loss

    Directory of Open Access Journals (Sweden)

    Jill B Firszt

    2013-12-01

    Full Text Available Monaural hearing induces auditory system reorganization. Imbalanced input also degrades time-intensity cues for sound localization and signal segregation for listening in noise. While there have been studies of bilateral auditory deprivation and later hearing restoration (e.g. cochlear implants, less is known about unilateral auditory deprivation and subsequent hearing improvement. We investigated effects of long-term congenital unilateral hearing loss on localization, speech understanding, and cortical organization following hearing recovery. Hearing in the congenitally affected ear of a 41 year old female improved significantly after stapedotomy and reconstruction. Pre-operative hearing threshold levels showed unilateral, mixed, moderately-severe to profound hearing loss. The contralateral ear had hearing threshold levels within normal limits. Testing was completed prior to, and three and nine months after surgery. Measurements were of sound localization with intensity-roved stimuli and speech recognition in various noise conditions. We also evoked magnetic resonance signals with monaural stimulation to the unaffected ear. Activation magnitudes were determined in core, belt, and parabelt auditory cortex regions via an interrupted single event design. Hearing improvement following 40 years of congenital unilateral hearing loss resulted in substantially improved sound localization and speech recognition in noise. Auditory cortex also reorganized. Contralateral auditory cortex responses were increased after hearing recovery and the extent of activated cortex was bilateral, including a greater portion of the posterior superior temporal plane. Thus, prolonged predominant monaural stimulation did not prevent auditory system changes consequent to restored binaural hearing. Results support future research of unilateral auditory deprivation effects and plasticity, with consideration for length of deprivation, age at hearing correction, degree and type

  20. THE EFFECTS OF SALICYLATE ON AUDITORY EVOKED POTENTIAL AMPLITWDE FROM THE AUDITORY CORTEX AND AUDITORY BRAINSTEM

    Institute of Scientific and Technical Information of China (English)

    Brian Sawka; SUN Wei

    2014-01-01

    Tinnitus has often been studied using salicylate in animal models as they are capable of inducing tempo-rary hearing loss and tinnitus. Studies have recently observed enhancement of auditory evoked responses of the auditory cortex (AC) post salicylate treatment which is also shown to be related to tinnitus like behavior in rats. The aim of this study was to observe if enhancements of the AC post salicylate treatment are also present at structures in the brainstem. Four male Sprague Dawley rats with AC implanted electrodes were tested for both AC and auditory brainstem response (ABR) recordings pre and post 250 mg/kg intraperitone-al injections of salicylate. The responses were recorded as the peak to trough amplitudes of P1-N1 (AC), ABR wave V, and ABR waveⅡ. AC responses resulted in statistically significant enhancement of ampli-tude at 2 hours post salicylate with 90 dB stimuli tone bursts of 4, 8, 12, and 20 kHz. Wave V of ABR re-sponses at 90 dB resulted in a statistically significant reduction of amplitude 2 hours post salicylate and a mean decrease of amplitude of 31%for 16 kHz. WaveⅡamplitudes at 2 hours post treatment were signifi-cantly reduced for 4, 12, and 20 kHz stimuli at 90 dB SPL. Our results suggest that the enhancement chang-es of the AC related to salicylate induced tinnitus are generated superior to the level of the inferior colliculus and may originate in the AC.

  1. Effect of auditory constraints on motor performance depends on stage of recovery post-stroke.

    Science.gov (United States)

    Aluru, Viswanath; Lu, Ying; Leung, Alan; Verghese, Joe; Raghavan, Preeti

    2014-01-01

    In order to develop evidence-based rehabilitation protocols post-stroke, one must first reconcile the vast heterogeneity in the post-stroke population and develop protocols to facilitate motor learning in the various subgroups. The main purpose of this study is to show that auditory constraints interact with the stage of recovery post-stroke to influence motor learning. We characterized the stages of upper limb recovery using task-based kinematic measures in 20 subjects with chronic hemiparesis. We used a bimanual wrist extension task, performed with a custom-made wrist trainer, to facilitate learning of wrist extension in the paretic hand under four auditory conditions: (1) without auditory cueing; (2) to non-musical happy sounds; (3) to self-selected music; and (4) to a metronome beat set at a comfortable tempo. Two bimanual trials (15 s each) were followed by one unimanual trial with the paretic hand over six cycles under each condition. Clinical metrics, wrist and arm kinematics, and electromyographic activity were recorded. Hierarchical cluster analysis with the Mahalanobis metric based on baseline speed and extent of wrist movement stratified subjects into three distinct groups, which reflected their stage of recovery: spastic paresis, spastic co-contraction, and minimal paresis. In spastic paresis, the metronome beat increased wrist extension, but also increased muscle co-activation across the wrist. In contrast, in spastic co-contraction, no auditory stimulation increased wrist extension and reduced co-activation. In minimal paresis, wrist extension did not improve under any condition. The results suggest that auditory task constraints interact with stage of recovery during motor learning after stroke, perhaps due to recruitment of distinct neural substrates over the course of recovery. The findings advance our understanding of the mechanisms of progression of motor recovery and lay the foundation for personalized treatment algorithms post-stroke.

  2. Hierarchical Control for Smart Grids

    DEFF Research Database (Denmark)

    Trangbæk, K; Bendtsen, Jan Dimon; Stoustrup, Jakob

    2011-01-01

    This paper deals with hierarchical model predictive control (MPC) of smart grid systems. The design consists of a high level MPC controller, a second level of so-called aggregators, which reduces the computational and communication-related load on the high-level control, and a lower level...... of autonomous consumers. The control system is tasked with balancing electric power production and consumption within the smart grid, and makes active use of the flexibility of a large number of power producing and/or power consuming units. The objective is to accommodate the load variation on the grid, arising...

  3. Auditory agnosia due to long-term severe hydrocephalus caused by spina bifida - specific auditory pathway versus nonspecific auditory pathway.

    Science.gov (United States)

    Zhang, Qing; Kaga, Kimitaka; Hayashi, Akimasa

    2011-07-01

    A 27-year-old female showed auditory agnosia after long-term severe hydrocephalus due to congenital spina bifida. After years of hydrocephalus, she gradually suffered from hearing loss in her right ear at 19 years of age, followed by her left ear. During the time when she retained some ability to hear, she experienced severe difficulty in distinguishing verbal, environmental, and musical instrumental sounds. However, her auditory brainstem response and distortion product otoacoustic emissions were largely intact in the left ear. Her bilateral auditory cortices were preserved, as shown by neuroimaging, whereas her auditory radiations were severely damaged owing to progressive hydrocephalus. Although she had a complete bilateral hearing loss, she felt great pleasure when exposed to music. After years of self-training to read lips, she regained fluent ability to communicate. Clinical manifestations of this patient indicate that auditory agnosia can occur after long-term hydrocephalus due to spina bifida; the secondary auditory pathway may play a role in both auditory perception and hearing rehabilitation.

  4. Relationship between Sympathetic Skin Responses and Auditory Hypersensitivity to Different Auditory Stimuli.

    Science.gov (United States)

    Kato, Fumi; Iwanaga, Ryoichiro; Chono, Mami; Fujihara, Saori; Tokunaga, Akiko; Murata, Jun; Tanaka, Koji; Nakane, Hideyuki; Tanaka, Goro

    2014-07-01

    [Purpose] Auditory hypersensitivity has been widely reported in patients with autism spectrum disorders. However, the neurological background of auditory hypersensitivity is currently not clear. The present study examined the relationship between sympathetic nervous system responses and auditory hypersensitivity induced by different types of auditory stimuli. [Methods] We exposed 20 healthy young adults to six different types of auditory stimuli. The amounts of palmar sweating resulting from the auditory stimuli were compared between groups with (hypersensitive) and without (non-hypersensitive) auditory hypersensitivity. [Results] Although no group × type of stimulus × first stimulus interaction was observed for the extent of reaction, significant type of stimulus × first stimulus interaction was noted for the extent of reaction. For an 80 dB-6,000 Hz stimulus, the trends for palmar sweating differed between the groups. For the first stimulus, the variance became larger in the hypersensitive group than in the non-hypersensitive group. [Conclusion] Subjects who regularly felt excessive reactions to auditory stimuli tended to have excessive sympathetic responses to repeated loud noises compared with subjects who did not feel excessive reactions. People with auditory hypersensitivity may be classified into several subtypes depending on their reaction patterns to auditory stimuli.

  5. Hierarchical Structures in Hypertext Learning Environments

    NARCIS (Netherlands)

    Bezdan, Eniko; Kester, Liesbeth; Kirschner, Paul A.

    2011-01-01

    Bezdan, E., Kester, L., & Kirschner, P. A. (2011, 9 September). Hierarchical Structures in Hypertext Learning Environments. Presentation for the visit of KU Leuven, Open University, Heerlen, The Netherlands.

  6. Auditory, Visual and Audiovisual Speech Processing Streams in Superior Temporal Sulcus.

    Science.gov (United States)

    Venezia, Jonathan H; Vaden, Kenneth I; Rong, Feng; Maddox, Dale; Saberi, Kourosh; Hickok, Gregory

    2017-01-01

    The human superior temporal sulcus (STS) is responsive to visual and auditory information, including sounds and facial cues during speech recognition. We investigated the functional organization of STS with respect to modality-specific and multimodal speech representations. Twenty younger adult participants were instructed to perform an oddball detection task and were presented with auditory, visual, and audiovisual speech stimuli, as well as auditory and visual nonspeech control stimuli in a block fMRI design. Consistent with a hypothesized anterior-posterior processing gradient in STS, auditory, visual and audiovisual stimuli produced the largest BOLD effects in anterior, posterior and middle STS (mSTS), respectively, based on whole-brain, linear mixed effects and principal component analyses. Notably, the mSTS exhibited preferential responses to multisensory stimulation, as well as speech compared to nonspeech. Within the mid-posterior and mSTS regions, response preferences changed gradually from visual, to multisensory, to auditory moving posterior to anterior. Post hoc analysis of visual regions in the posterior STS revealed that a single subregion bordering the mSTS was insensitive to differences in low-level motion kinematics yet distinguished between visual speech and nonspeech based on multi-voxel activation patterns. These results suggest that auditory and visual speech representations are elaborated gradually within anterior and posterior processing streams, respectively, and may be integrated within the mSTS, which is sensitive to more abstract speech information within and across presentation modalities. The spatial organization of STS is consistent with processing streams that are hypothesized to synthesize perceptual speech representations from sensory signals that provide convergent information from visual and auditory modalities.

  7. Spatial auditory processing in pinnipeds

    Science.gov (United States)

    Holt, Marla M.

    Given the biological importance of sound for a variety of activities, pinnipeds must be able to obtain spatial information about their surroundings thorough acoustic input in the absence of other sensory cues. The three chapters of this dissertation address spatial auditory processing capabilities of pinnipeds in air given that these amphibious animals use acoustic signals for reproduction and survival on land. Two chapters are comparative lab-based studies that utilized psychophysical approaches conducted in an acoustic chamber. Chapter 1 addressed the frequency-dependent sound localization abilities at azimuth of three pinniped species (the harbor seal, Phoca vitulina, the California sea lion, Zalophus californianus, and the northern elephant seal, Mirounga angustirostris). While performances of the sea lion and harbor seal were consistent with the duplex theory of sound localization, the elephant seal, a low-frequency hearing specialist, showed a decreased ability to localize the highest frequencies tested. In Chapter 2 spatial release from masking (SRM), which occurs when a signal and masker are spatially separated resulting in improvement in signal detectability relative to conditions in which they are co-located, was determined in a harbor seal and sea lion. Absolute and masked thresholds were measured at three frequencies and azimuths to determine the detection advantages afforded by this type of spatial auditory processing. Results showed that hearing sensitivity was enhanced by up to 19 and 12 dB in the harbor seal and sea lion, respectively, when the signal and masker were spatially separated. Chapter 3 was a field-based study that quantified both sender and receiver variables of the directional properties of male northern elephant seal calls produce within communication system that serves to delineate dominance status. This included measuring call directivity patterns, observing male-male vocally-mediated interactions, and an acoustic playback study

  8. Auditory filters at low-frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Møller, Henrik

    2009-01-01

    Prediction and assessment of low-frequency noise problems requires information about the auditory filter characteristics at low-frequencies. Unfortunately, data at low-frequencies is scarce and practically no results have been published for frequencies below 100 Hz. Extrapolation of ERB results......-ear transfer function), the asymmetry of the auditory filter changed from steeper high-frequency slopes at 1000 Hz to steeper low-frequency slopes below 100 Hz. Increasing steepness at low-frequencies of the middle-ear high-pass filter is thought to cause this effect. The dynamic range of the auditory filter...

  9. Assessing the aging effect on auditory-verbal memory by Persian version of dichotic auditory verbal memory test

    Directory of Open Access Journals (Sweden)

    Zahra Shahidipour

    2014-01-01

    Conclusion: Based on the obtained results, significant reduction in auditory memory was seen in aged group and the Persian version of dichotic auditory-verbal memory test, like many other auditory verbal memory tests, showed the aging effects on auditory verbal memory performance.

  10. Auditory free classification of nonnative speech

    Science.gov (United States)

    Atagi, Eriko; Bent, Tessa

    2013-01-01

    Through experience with speech variability, listeners build categories of indexical speech characteristics including categories for talker, gender, and dialect. The auditory free classification task—a task in which listeners freely group talkers based on audio samples—has been a useful tool for examining listeners’ representations of some of these characteristics including regional dialects and different languages. The free classification task was employed in the current study to examine the perceptual representation of nonnative speech. The category structure and salient perceptual dimensions of nonnative speech were investigated from two perspectives: general similarity and perceived native language background. Talker intelligibility and whether native talkers were included were manipulated to test stimulus set effects. Results showed that degree of accent was a highly salient feature of nonnative speech for classification based on general similarity and on perceived native language background. This salience, however, was attenuated when listeners were listening to highly intelligible stimuli and attending to the talkers’ native language backgrounds. These results suggest that the context in which nonnative speech stimuli are presented—such as the listeners’ attention to the talkers’ native language and the variability of stimulus intelligibility—can influence listeners’ perceptual organization of nonnative speech. PMID:24363470

  11. Auditory free classification of nonnative speech.

    Science.gov (United States)

    Atagi, Eriko; Bent, Tessa

    2013-11-01

    Through experience with speech variability, listeners build categories of indexical speech characteristics including categories for talker, gender, and dialect. The auditory free classification task-a task in which listeners freely group talkers based on audio samples-has been a useful tool for examining listeners' representations of some of these characteristics including regional dialects and different languages. The free classification task was employed in the current study to examine the perceptual representation of nonnative speech. The category structure and salient perceptual dimensions of nonnative speech were investigated from two perspectives: general similarity and perceived native language background. Talker intelligibility and whether native talkers were included were manipulated to test stimulus set effects. Results showed that degree of accent was a highly salient feature of nonnative speech for classification based on general similarity and on perceived native language background. This salience, however, was attenuated when listeners were listening to highly intelligible stimuli and attending to the talkers' native language backgrounds. These results suggest that the context in which nonnative speech stimuli are presented-such as the listeners' attention to the talkers' native language and the variability of stimulus intelligibility-can influence listeners' perceptual organization of nonnative speech.

  12. Use of auditory learning to manage listening problems in children

    OpenAIRE

    Moore, David R.; Halliday, Lorna F.; Amitay, Sygal

    2008-01-01

    This paper reviews recent studies that have used adaptive auditory training to address communication problems experienced by some children in their everyday life. It considers the auditory contribution to developmental listening and language problems and the underlying principles of auditory learning that may drive further refinement of auditory learning applications. Following strong claims that language and listening skills in children could be improved by auditory learning, researchers hav...

  13. Multisorted Tree-Algebras for Hierarchical Resources Allocation

    Directory of Open Access Journals (Sweden)

    Erick Patrick Zobo

    2015-01-01

    Full Text Available This paper presents a generic abstract model for the study of disparities between goals and results in hierarchical multiresources allocation systems. In an organization, disparities in resource allocation may occur, when, after comparison of a resource allocation decision with an allocation reference goal or property, some agents have surplus resources to accomplish their tasks, while at the same time other agents have deficits of expected resources. In the real world, these situations are frequently encountered in organizations facing scarcity of resources and/or inefficient management. These disparities can be corrected using allocation decisions, by measuring and reducing gradually such disparities and their related costs, without totally canceling the existing resource distribution. While a lot of research has been carried out in the area of resource allocation, this specific class of problems has not yet been formally studied. The paper exposes the results of an exploratory research study of this class of problems. It identifies the commonalities of the family of hierarchical multiresource allocation systems and proposes the concept of multisorted tree-algebra for the modeling of these problems. The research presented here is not yet an in-depth descriptive research study of the mathematical theory of multisorted tree-algebra, but a formal study on modelling hierarchical multiresource allocation problems.

  14. Spectral characterization of hierarchical network modularity and limits of modularity detection.

    Directory of Open Access Journals (Sweden)

    Somwrita Sarkar

    Full Text Available Many real world networks are reported to have hierarchically modular organization. However, there exists no algorithm-independent metric to characterize hierarchical modularity in a complex system. The main results of the paper are a set of methods to address this problem. First, classical results from random matrix theory are used to derive the spectrum of a typical stochastic block model hierarchical modular network form. Second, it is shown that hierarchical modularity can be fingerprinted using the spectrum of its largest eigenvalues and gaps between clusters of closely spaced eigenvalues that are well separated from the bulk distribution of eigenvalues around the origin. Third, some well-known results on fingerprinting non-hierarchical modularity in networks automatically follow as special cases, threreby unifying these previously fragmented results. Finally, using these spectral results, it is found that the limits of detection of modularity can be empirically established by studying the mean values of the largest eigenvalues and the limits of the bulk distribution of eigenvalues for an ensemble of networks. It is shown that even when modularity and hierarchical modularity are present in a weak form in the network, they are impossible to detect, because some of the leading eigenvalues fall within the bulk distribution. This provides a threshold for the detection of modularity. Eigenvalue distributions of some technological, social, and biological networks are studied, and the implications of detecting hierarchical modularity in real world networks are discussed.

  15. Hierarchy concepts: classification and preparation strategies for zeolite containing materials with hierarchical porosity.

    Science.gov (United States)

    Schwieger, Wilhelm; Machoke, Albert Gonche; Weissenberger, Tobias; Inayat, Amer; Selvam, Thangaraj; Klumpp, Michael; Inayat, Alexandra

    2016-06-13

    'Hierarchy' is a property which can be attributed to a manifold of different immaterial systems, such as ideas, items and organisations or material ones like biological systems within living organisms or artificial, man-made constructions. The property 'hierarchy' is mainly characterised by a certain ordering of individual elements relative to each other, often in combination with a certain degree of branching. Especially mass-flow related systems in the natural environment feature special hierarchically branched patterns. This review is a survey into the world of hierarchical systems with special focus on hierarchically porous zeolite materials. A classification of hierarchical porosity is proposed based on the flow distribution pattern within the respective pore systems. In addition, this review might serve as a toolbox providing several synthetic and post-synthetic strategies to prepare zeolitic or zeolite containing material with tailored hierarchical porosity. Very often, such strategies with their underlying principles were developed for improving the performance of the final materials in different technical applications like adsorptive or catalytic processes. In the present review, besides on the hierarchically porous all-zeolite material, special focus is laid on the preparation of zeolitic composite materials with hierarchical porosity capable to face the demands of industrial application.

  16. Frequency band-importance functions for auditory and auditory-visual speech recognition

    Science.gov (United States)

    Grant, Ken W.

    2005-04-01

    In many everyday listening environments, speech communication involves the integration of both acoustic and visual speech cues. This is especially true in noisy and reverberant environments where the speech signal is highly degraded, or when the listener has a hearing impairment. Understanding the mechanisms involved in auditory-visual integration is a primary interest of this work. Of particular interest is whether listeners are able to allocate their attention to various frequency regions of the speech signal differently under auditory-visual conditions and auditory-alone conditions. For auditory speech recognition, the most important frequency regions tend to be around 1500-3000 Hz, corresponding roughly to important acoustic cues for place of articulation. The purpose of this study is to determine the most important frequency region under auditory-visual speech conditions. Frequency band-importance functions for auditory and auditory-visual conditions were obtained by having subjects identify speech tokens under conditions where the speech-to-noise ratio of different parts of the speech spectrum is independently and randomly varied on every trial. Point biserial correlations were computed for each separate spectral region and the normalized correlations are interpreted as weights indicating the importance of each region. Relations among frequency-importance functions for auditory and auditory-visual conditions will be discussed.

  17. Discovering hierarchical structure in normal relational data

    DEFF Research Database (Denmark)

    Schmidt, Mikkel Nørgaard; Herlau, Tue; Mørup, Morten

    2014-01-01

    Hierarchical clustering is a widely used tool for structuring and visualizing complex data using similarity. Traditionally, hierarchical clustering is based on local heuristics that do not explicitly provide assessment of the statistical saliency of the extracted hierarchy. We propose a non-param...

  18. Discursive Hierarchical Patterning in Economics Cases

    Science.gov (United States)

    Lung, Jane

    2011-01-01

    This paper attempts to apply Lung's (2008) model of the discursive hierarchical patterning of cases to a closer and more specific study of Economics cases and proposes a model of the distinct discursive hierarchical patterning of the same. It examines a corpus of 150 Economics cases with a view to uncovering the patterns of discourse construction.…

  19. A Model of Hierarchical Key Assignment Scheme

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhigang; ZHAO Jing; XU Maozhi

    2006-01-01

    A model of the hierarchical key assignment scheme is approached in this paper, which can be used with any cryptography algorithm. Besides, the optimal dynamic control property of a hierarchical key assignment scheme will be defined in this paper. Also, our scheme model will meet this property.

  20. Cooperative mechanism of self-regulation in hierarchical living systems

    CERN Document Server

    Lubashevsky, I A

    1998-01-01

    We study the problem of how a ``living'' system complex in structure can respond perfectly to local changes in the environment. Such a system is assumed to consist of a distributed ``living'' medium and a hierarchical ``supplying'' network that provides this medium with ``nutritious'' products. Because of the hierarchical organization each element of the supplying network has to behave in a self-consistent way for the system can adapt to changes in the environment. We propose a cooperative mechanism of self-regulation by which the system as a whole can react perfectly. This mechanism is based on an individual response of each element to the corresponding small piece of the information on the state of the ``living'' medium. The conservation of flux through the supplying network gives rise to a certain processing of information and the self-consistent behavior of the elements, leading to the perfect self-regulation. The corresponding equations governing the ``living'' medium state are obtained.

  1. Hierarchical nanostructure and synergy of multimolecular signalling complexes

    Science.gov (United States)

    Sherman, Eilon; Barr, Valarie A.; Merrill, Robert K.; Regan, Carole K.; Sommers, Connie L.; Samelson, Lawrence E.

    2016-01-01

    Signalling complexes are dynamic, multimolecular structures and sites for intracellular signal transduction. Although they play a crucial role in cellular activation, current research techniques fail to resolve their structure in intact cells. Here we present a multicolour, photoactivated localization microscopy approach for imaging multiple types of single molecules in fixed and live cells and statistical tools to determine the nanoscale organization, topology and synergy of molecular interactions in signalling complexes downstream of the T-cell antigen receptor. We observe that signalling complexes nucleated at the key adapter LAT show a hierarchical topology. The critical enzymes PLCγ1 and VAV1 localize to the centre of LAT-based complexes, and the adapter SLP-76 and actin molecules localize to the periphery. Conditional second-order statistics reveal a hierarchical network of synergic interactions between these molecules. Our results extend our understanding of the nanostructure of signalling complexes and are relevant to studying a wide range of multimolecular complexes. PMID:27396911

  2. Hierarchical nanostructure and synergy of multimolecular signalling complexes

    Science.gov (United States)

    Sherman, Eilon; Barr, Valarie A.; Merrill, Robert K.; Regan, Carole K.; Sommers, Connie L.; Samelson, Lawrence E.

    2016-07-01

    Signalling complexes are dynamic, multimolecular structures and sites for intracellular signal transduction. Although they play a crucial role in cellular activation, current research techniques fail to resolve their structure in intact cells. Here we present a multicolour, photoactivated localization microscopy approach for imaging multiple types of single molecules in fixed and live cells and statistical tools to determine the nanoscale organization, topology and synergy of molecular interactions in signalling complexes downstream of the T-cell antigen receptor. We observe that signalling complexes nucleated at the key adapter LAT show a hierarchical topology. The critical enzymes PLCγ1 and VAV1 localize to the centre of LAT-based complexes, and the adapter SLP-76 and actin molecules localize to the periphery. Conditional second-order statistics reveal a hierarchical network of synergic interactions between these molecules. Our results extend our understanding of the nanostructure of signalling complexes and are relevant to studying a wide range of multimolecular complexes.

  3. Organizations

    DEFF Research Database (Denmark)

    Hatch, Mary Jo

    Most of us recognize that organizations are everywhere. You meet them on every street corner in the form of families and shops, study in them, work for them, buy from them, pay taxes to them. But have you given much thought to where they came from, what they are today, and what they might become...... in the future? How and why do they have so much influence over us, and what influences them? How do they contribute to and detract from the meaningfulness of lives, and how might we improve them so they better serve our needs and desires? This Very Short Introductions addresses all of these questions...

  4. Efficient coding of spectrotemporal binaural sounds leads to emergence of the auditory space representation

    Directory of Open Access Journals (Sweden)

    Wiktor eMlynarski

    2014-03-01

    Full Text Available To date a number of studies have shown that receptive field shapes of early sensory neurons can be reproduced by optimizing coding efficiency of natural stimulus ensembles. A still unresolved question is whether the efficientcoding hypothesis explains formation of neurons which explicitly represent environmental features of different functional importance. This paper proposes that the spatial selectivity of higher auditory neurons emerges as a direct consequence of learning efficient codes for natural binaural sounds. Firstly, it is demonstrated that a linear efficient coding transform - Independent Component Analysis (ICA trained on spectrograms of naturalistic simulated binaural sounds extracts spatial information present in the signal. A simple hierarchical ICA extension allowing for decoding of sound position is proposed. Furthermore, it is shown that units revealing spatial selectivity can be learned from a binaural recording of a natural auditory scene. In both cases a relatively small subpopulation of learned spectrogram features suffices to perform accurate sound localization. Representation of the auditory space is therefore learned in a purely unsupervised way by maximizing the coding efficiency and without any task-specific constraints. This results imply that efficient coding is a useful strategy for learning structures which allow for making behaviorally vital inferences about the environment.

  5. Efficient coding of spectrotemporal binaural sounds leads to emergence of the auditory space representation.

    Science.gov (United States)

    Młynarski, Wiktor

    2014-01-01

    To date a number of studies have shown that receptive field shapes of early sensory neurons can be reproduced by optimizing coding efficiency of natural stimulus ensembles. A still unresolved question is whether the efficient coding hypothesis explains formation of neurons which explicitly represent environmental features of different functional importance. This paper proposes that the spatial selectivity of higher auditory neurons emerges as a direct consequence of learning efficient codes for natural binaural sounds. Firstly, it is demonstrated that a linear efficient coding transform-Independent Component Analysis (ICA) trained on spectrograms of naturalistic simulated binaural sounds extracts spatial information present in the signal. A simple hierarchical ICA extension allowing for decoding of sound position is proposed. Furthermore, it is shown that units revealing spatial selectivity can be learned from a binaural recording of a natural auditory scene. In both cases a relatively small subpopulation of learned spectrogram features suffices to perform accurate sound localization. Representation of the auditory space is therefore learned in a purely unsupervised way by maximizing the coding efficiency and without any task-specific constraints. This results imply that efficient coding is a useful strategy for learning structures which allow for making behaviorally vital inferences about the environment.

  6. Cognitive representation of "musical fractals": Processing hierarchy and recursion in the auditory domain.

    Science.gov (United States)

    Martins, Mauricio Dias; Gingras, Bruno; Puig-Waldmueller, Estela; Fitch, W Tecumseh

    2017-04-01

    The human ability to process hierarchical structures has been a longstanding research topic. However, the nature of the cognitive machinery underlying this faculty remains controversial. Recursion, the ability to embed structures within structures of the same kind, has been proposed as a key component of our ability to parse and generate complex hierarchies. Here, we investigated the cognitive representation of both recursive and iterative processes in the auditory domain. The experiment used a two-alternative forced-choice paradigm: participants were exposed to three-step processes in which pure-tone sequences were built either through recursive or iterative processes, and had to choose the correct completion. Foils were constructed according to generative processes that did not match the previous steps. Both musicians and non-musicians were able to represent recursion in the auditory domain, although musicians performed better. We also observed that general 'musical' aptitudes played a role in both recursion and iteration, although the influence of musical training was somehow independent from melodic memory. Moreover, unlike iteration, recursion in audition was well correlated with its non-auditory (recursive) analogues in the visual and action sequencing domains. These results suggest that the cognitive machinery involved in establishing recursive representations is domain-general, even though this machinery requires access to information resulting from domain-specific processes. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Beta-Band Oscillations Represent Auditory Beat and Its Metrical Hierarchy in Perception and Imagery.

    Science.gov (United States)

    Fujioka, Takako; Ross, Bernhard; Trainor, Laurel J

    2015-11-11

    Dancing to music involves synchronized movements, which can be at the basic beat level or higher hierarchical metrical levels, as in a march (groups of two basic beats, one-two-one-two …) or waltz (groups of three basic beats, one-two-three-one-two-three …). Our previous human magnetoencephalography studies revealed that the subjective sense of meter influences auditory evoked responses phase locked to the stimulus. Moreover, the timing of metronome clicks was represented in periodic modulation of induced (non-phase locked) β-band (13-30 Hz) oscillation in bilateral auditory and sensorimotor cortices. Here, we further examine whether acoustically accented and subjectively imagined metric processing in march and waltz contexts during listening to isochronous beats were reflected in neuromagnetic β-band activity recorded from young adult musicians. First, we replicated previous findings of beat-related β-power decrease at 200 ms after the beat followed by a predictive increase toward the onset of the next beat. Second, we showed that the β decrease was significantly influenced by the metrical structure, as reflected by differences across beat type for both perception and imagery conditions. Specifically, the β-power decrease associated with imagined downbeats (the count "one") was larger than that for both the upbeat (preceding the count "one") in the march, and for the middle beat in the waltz. Moreover, beamformer source analysis for the whole brain volume revealed that the metric contrasts involved auditory and sensorimotor cortices; frontal, parietal, and inferior temporal lobes; and cerebellum. We suggest that the observed β-band activities reflect a translation of timing information to auditory-motor coordination. With magnetoencephalography, we examined β-band oscillatory activities around 20 Hz while participants listened to metronome beats and imagined musical meters such as a march and waltz. We demonstrated that β-band event

  8. Galaxy formation through hierarchical clustering

    Science.gov (United States)

    White, Simon D. M.; Frenk, Carlos S.

    1991-01-01

    Analytic methods for studying the formation of galaxies by gas condensation within massive dark halos are presented. The present scheme applies to cosmogonies where structure grows through hierarchical clustering of a mixture of gas and dissipationless dark matter. The simplest models consistent with the current understanding of N-body work on dissipationless clustering, and that of numerical and analytic work on gas evolution and cooling are adopted. Standard models for the evolution of the stellar population are also employed, and new models for the way star formation heats and enriches the surrounding gas are constructed. Detailed results are presented for a cold dark matter universe with Omega = 1 and H(0) = 50 km/s/Mpc, but the present methods are applicable to other models. The present luminosity functions contain significantly more faint galaxies than are observed.

  9. Groups possessing extensive hierarchical decompositions

    CERN Document Server

    Januszkiewicz, T; Leary, I J

    2009-01-01

    Kropholler's class of groups is the smallest class of groups which contains all finite groups and is closed under the following operator: whenever $G$ admits a finite-dimensional contractible $G$-CW-complex in which all stabilizer groups are in the class, then $G$ is itself in the class. Kropholler's class admits a hierarchical structure, i.e., a natural filtration indexed by the ordinals. For example, stage 0 of the hierarchy is the class of all finite groups, and stage 1 contains all groups of finite virtual cohomological dimension. We show that for each countable ordinal $\\alpha$, there is a countable group that is in Kropholler's class which does not appear until the $\\alpha+1$st stage of the hierarchy. Previously this was known only for $\\alpha= 0$, 1 and 2. The groups that we construct contain torsion. We also review the construction of a torsion-free group that lies in the third stage of the hierarchy.

  10. Quantum transport through hierarchical structures.

    Science.gov (United States)

    Boettcher, S; Varghese, C; Novotny, M A

    2011-04-01

    The transport of quantum electrons through hierarchical lattices is of interest because such lattices have some properties of both regular lattices and random systems. We calculate the electron transmission as a function of energy in the tight-binding approximation for two related Hanoi networks. HN3 is a Hanoi network with every site having three bonds. HN5 has additional bonds added to HN3 to make the average number of bonds per site equal to five. We present a renormalization group approach to solve the matrix equation involved in this quantum transport calculation. We observe band gaps in HN3, while no such band gaps are observed in linear networks or in HN5. We provide a detailed scaling analysis near the edges of these band gaps.

  11. Hierarchical networks of scientific journals

    CERN Document Server

    Palla, Gergely; Mones, Enys; Pollner, Péter; Vicsek, Tamás

    2015-01-01

    Scientific journals are the repositories of the gradually accumulating knowledge of mankind about the world surrounding us. Just as our knowledge is organised into classes ranging from major disciplines, subjects and fields to increasingly specific topics, journals can also be categorised into groups using various metrics. In addition to the set of topics characteristic for a journal, they can also be ranked regarding their relevance from the point of overall influence. One widespread measure is impact factor, but in the present paper we intend to reconstruct a much more detailed description by studying the hierarchical relations between the journals based on citation data. We use a measure related to the notion of m-reaching centrality and find a network which shows the level of influence of a journal from the point of the direction and efficiency with which information spreads through the network. We can also obtain an alternative network using a suitably modified nested hierarchy extraction method applied ...

  12. Adaptive Sampling in Hierarchical Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Knap, J; Barton, N R; Hornung, R D; Arsenlis, A; Becker, R; Jefferson, D R

    2007-07-09

    We propose an adaptive sampling methodology for hierarchical multi-scale simulation. The method utilizes a moving kriging interpolation to significantly reduce the number of evaluations of finer-scale response functions to provide essential constitutive information to a coarser-scale simulation model. The underlying interpolation scheme is unstructured and adaptive to handle the transient nature of a simulation. To handle the dynamic construction and searching of a potentially large set of finer-scale response data, we employ a dynamic metric tree database. We study the performance of our adaptive sampling methodology for a two-level multi-scale model involving a coarse-scale finite element simulation and a finer-scale crystal plasticity based constitutive law.

  13. Multicollinearity in hierarchical linear models.

    Science.gov (United States)

    Yu, Han; Jiang, Shanhe; Land, Kenneth C

    2015-09-01

    This study investigates an ill-posed problem (multicollinearity) in Hierarchical Linear Models from both the data and the model perspectives. We propose an intuitive, effective approach to diagnosing the presence of multicollinearity and its remedies in this class of models. A simulation study demonstrates the impacts of multicollinearity on coefficient estimates, associated standard errors, and variance components at various levels of multicollinearity for finite sample sizes typical in social science studies. We further investigate the role multicollinearity plays at each level for estimation of coefficient parameters in terms of shrinkage. Based on these analyses, we recommend a top-down method for assessing multicollinearity in HLMs that first examines the contextual predictors (Level-2 in a two-level model) and then the individual predictors (Level-1) and uses the results for data collection, research problem redefinition, model re-specification, variable selection and estimation of a final model.

  14. Hierarchically Nanostructured Materials for Sustainable Environmental Applications

    Science.gov (United States)

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-11-01

    This article presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions and multiple functionalities towards water remediation, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology.

  15. A neural signature of hierarchical reinforcement learning.

    Science.gov (United States)

    Ribas-Fernandes, José J F; Solway, Alec; Diuk, Carlos; McGuire, Joseph T; Barto, Andrew G; Niv, Yael; Botvinick, Matthew M

    2011-07-28

    Human behavior displays hierarchical structure: simple actions cohere into subtask sequences, which work together to accomplish overall task goals. Although the neural substrates of such hierarchy have been the target of increasing research, they remain poorly understood. We propose that the computations supporting hierarchical behavior may relate to those in hierarchical reinforcement learning (HRL), a machine-learning framework that extends reinforcement-learning mechanisms into hierarchical domains. To test this, we leveraged a distinctive prediction arising from HRL. In ordinary reinforcement learning, reward prediction errors are computed when there is an unanticipated change in the prospects for accomplishing overall task goals. HRL entails that prediction errors should also occur in relation to task subgoals. In three neuroimaging studies we observed neural responses consistent with such subgoal-related reward prediction errors, within structures previously implicated in reinforcement learning. The results reported support the relevance of HRL to the neural processes underlying hierarchical behavior.

  16. Hierarchically nanostructured materials for sustainable environmental applications

    Science.gov (United States)

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-01-01

    This review presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions, and multiple functionalities toward water remediation, biosensing, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing, and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology. PMID:24790946

  17. Hierarchically Nanostructured Materials for Sustainable Environmental Applications

    Directory of Open Access Journals (Sweden)

    Zheng eRen

    2013-11-01

    Full Text Available This article presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions and multiple functionalities towards water remediation, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology.

  18. Activation of Heschl's gyrus during auditory hallucinations

    National Research Council Canada - National Science Library

    Dierks, T; Linden, D E; Jandl, M; Formisano, E; Goebel, R; Lanfermann, H; Singer, W

    1999-01-01

    Apart from being a common feature of mental illness, auditory hallucinations provide an intriguing model for the study of internally generated sensory perceptions that are attributed to external sources...

  19. [Approaches to therapy of auditory agnosia].

    Science.gov (United States)

    Fechtelpeter, A; Göddenhenrich, S; Huber, W; Springer, L

    1990-01-01

    In a 41-year-old stroke patient with bitemporal brain damage, we found severe signs of auditory agnosia 6 months after onset. Recognition of environmental sounds was extremely impaired when tested in a multiple choice sound-picture matching task, whereas auditory discrimination between sounds and picture identifications by written names was almost undisturbed. In a therapy experiment, we tried to enhance sound recognition via semantic categorization and association, imitation of sound and analysis of auditory features, respectively. The stimulation of conscious auditory analysis proved to be increasingly effective over a 4-week period of therapy. We were able to show that the patient's improvement was not only a simple effect of practicing, but it was stable and carried over to nontrained items.

  20. Prelingual auditory verbal agnosia, A rare condition

    National Research Council Canada - National Science Library

    Violeta Necula; Cristina Mirela Stamate; Krishna Luchoo; Marcel Cosgarea

    2017-01-01

    Auditory agnosia, agnosia for speech is a rare condition, caused mostly by stroke, in adults, while in children it is often a sequel of herpes simplex encephalitis or is associated with epilepsy, in Landau–Kleffner syndrome...

  1. Auditory neuroplasticity, hearing loss and cochlear implants.

    Science.gov (United States)

    Ryugo, David

    2015-07-01

    Data from our laboratory show that the auditory brain is highly malleable by experience. We establish a base of knowledge that describes the normal structure and workings at the initial stages of the central auditory system. This research is expanded to include the associated pathology in the auditory brain stem created by hearing loss. Utilizing the congenitally deaf white cat, we demonstrate the way that cells, synapses, and circuits are pathologically affected by sound deprivation. We further show that the restoration of auditory nerve activity via electrical stimulation through cochlear implants serves to correct key features of brain pathology caused by hearing loss. The data suggest that rigorous training with cochlear implants and/or hearing aids offers the promise of heretofore unattained benefits.

  2. Auditory-visual spatial interaction and modularity

    Science.gov (United States)

    Radeau, M

    1994-02-01

    The results of dealing with the conditions for pairing visual and auditory data coming from spatially separate locations argue for cognitive impenetrability and computational autonomy, the pairing rules being the Gestalt principles of common fate and proximity. Other data provide evidence for pairing with several properties of modular functioning. Arguments for domain specificity are inferred from comparison with audio-visual speech. Suggestion of innate specification can be found in developmental data indicating that the grouping of visual and auditory signals is supported very early in life by the same principles that operate in adults. Support for a specific neural architecture comes from neurophysiological studies of the bimodal (auditory-visual) neurons of the cat superior colliculus. Auditory-visual pairing thus seems to present the four main properties of the Fodorian module.

  3. Effect of omega-3 on auditory system

    Directory of Open Access Journals (Sweden)

    Vida Rahimi

    2014-01-01

    Full Text Available Background and Aim: Omega-3 fatty acid have structural and biological roles in the body 's various systems . Numerous studies have tried to research about it. Auditory system is affected a s well. The aim of this article was to review the researches about the effect of omega-3 on auditory system.Methods: We searched Medline , Google Scholar, PubMed, Cochrane Library and SID search engines with the "auditory" and "omega-3" keywords and read textbooks about this subject between 19 70 and 20 13.Conclusion: Both excess and deficient amounts of dietary omega-3 fatty acid can cause harmful effects on fetal and infant growth and development of brain and central nervous system esspesially auditory system. It is important to determine the adequate dosage of omega-3.

  4. Environment for Auditory Research Facility (EAR)

    Data.gov (United States)

    Federal Laboratory Consortium — EAR is an auditory perception and communication research center enabling state-of-the-art simulation of various indoor and outdoor acoustic environments. The heart...

  5. Hierarchically Nanoporous Bioactive Glasses for High Efficiency Immobilization of Enzymes

    DEFF Research Database (Denmark)

    He, W.; Min, D.D.; Zhang, X.D.

    2014-01-01

    Bioactive glasses with hierarchical nanoporosity and structures have been heavily involved in immobilization of enzymes. Because of meticulous design and ingenious hierarchical nanostructuration of porosities from yeast cell biotemplates, hierarchically nanostructured porous bioactive glasses can...

  6. Hierarchical mutual information for the comparison of hierarchical community structures in complex networks

    CERN Document Server

    Perotti, Juan Ignacio; Caldarelli, Guido

    2015-01-01

    The quest for a quantitative characterization of community and modular structure of complex networks produced a variety of methods and algorithms to classify different networks. However, it is not clear if such methods provide consistent, robust and meaningful results when considering hierarchies as a whole. Part of the problem is the lack of a similarity measure for the comparison of hierarchical community structures. In this work we give a contribution by introducing the {\\it hierarchical mutual information}, which is a generalization of the traditional mutual information, and allows to compare hierarchical partitions and hierarchical community structures. The {\\it normalized} version of the hierarchical mutual information should behave analogously to the traditional normalized mutual information. Here, the correct behavior of the hierarchical mutual information is corroborated on an extensive battery of numerical experiments. The experiments are performed on artificial hierarchies, and on the hierarchical ...

  7. [A case of carcinoma adenoides cysticum in the external auditory canal].

    Science.gov (United States)

    Soboczyński, R; Wojnowski, W

    2001-01-01

    The authors present a case of a woman aged 31 with carcinoma adenoides cysticum at external auditory canal. The tumor was surgically removed; after 9 month a recrudescence was ascertained but there were no metastasis to other organs. The tumor was once more surgically removed. Now it has been a year of observation and no renewal of neoplastic process was noticed.

  8. A critical period for auditory thalamocortical connectivity

    DEFF Research Database (Denmark)

    Rinaldi Barkat, Tania; Polley, Daniel B; Hensch, Takao K

    2011-01-01

    connectivity by in vivo recordings and day-by-day voltage-sensitive dye imaging in an acute brain slice preparation. Passive tone-rearing modified response strength and topography in mouse primary auditory cortex (A1) during a brief, 3-d window, but did not alter tonotopic maps in the thalamus. Gene...... locus of change for the tonotopic plasticity. The evolving postnatal connectivity between thalamus and cortex in the days following hearing onset may therefore determine a critical period for auditory processing....

  9. Perceptual consequences of disrupted auditory nerve activity.

    Science.gov (United States)

    Zeng, Fan-Gang; Kong, Ying-Yee; Michalewski, Henry J; Starr, Arnold

    2005-06-01

    Perceptual consequences of disrupted auditory nerve activity were systematically studied in 21 subjects who had been clinically diagnosed with auditory neuropathy (AN), a recently defined disorder characterized by normal outer hair cell function but disrupted auditory nerve function. Neurological and electrophysical evidence suggests that disrupted auditory nerve activity is due to desynchronized or reduced neural activity or both. Psychophysical measures showed that the disrupted neural activity has minimal effects on intensity-related perception, such as loudness discrimination, pitch discrimination at high frequencies, and sound localization using interaural level differences. In contrast, the disrupted neural activity significantly impairs timing related perception, such as pitch discrimination at low frequencies, temporal integration, gap detection, temporal modulation detection, backward and forward masking, signal detection in noise, binaural beats, and sound localization using interaural time differences. These perceptual consequences are the opposite of what is typically observed in cochlear-impaired subjects who have impaired intensity perception but relatively normal temporal processing after taking their impaired intensity perception into account. These differences in perceptual consequences between auditory neuropathy and cochlear damage suggest the use of different neural codes in auditory perception: a suboptimal spike count code for intensity processing, a synchronized spike code for temporal processing, and a duplex code for frequency processing. We also proposed two underlying physiological models based on desynchronized and reduced discharge in the auditory nerve to successfully account for the observed neurological and behavioral data. These methods and measures cannot differentiate between these two AN models, but future studies using electric stimulation of the auditory nerve via a cochlear implant might. These results not only show the unique

  10. Synthesis of New Dynamic Movement Primitives Through Search in a Hierarchical Database of Example Movements

    Directory of Open Access Journals (Sweden)

    Miha Deniša

    2015-10-01

    Full Text Available This paper presents a novel approach to discovering motor primitives in a hierarchical database of example trajectories. An initial set of example trajectories is obtained by human demonstration. The trajectories are clustered and organized in a binary tree-like hierarchical structure, from which transition graphs at different levels of granularity are constructed. A novel procedure for searching in this hierarchical structure is presented. It can exploit the interdependencies between movements and can discover new series of partial paths. From these partial paths, complete new movements are generated by encoding them as dynamic movement primitives. In this way, the number of example trajectories that must be acquired with the assistance of a human teacher can be reduced. By combining the results of the hierarchical search with statistical generalization techniques, a complete representation of new, not directly demonstrated, movement primitives can be generated.

  11. A Review on the Fabrication of Hierarchical ZnO Nanostructures for Photocatalysis Application

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    Yi Xia

    2016-11-01

    Full Text Available Semiconductor photocatalysis provides potential solutions for many energy and environmental-related issues. Recently, various semiconductors with hierarchical nanostructures have been fabricated to achieve efficient photocatalysts owing to their multiple advantages, such as high surface area, porous structures, as well as enhanced light harvesting. ZnO has been widely investigated and considered as the most promising alternative photocatalyst to TiO2. Herein, we present a review on the fabrication methods, growth mechanisms and photocatalytic applications of hierarchical ZnO nanostructures. Various synthetic strategies and growth mechanisms, including multistep sequential growth routes, template-based synthesis, template-free self-organization and precursor or self-templating strategies, are highlighted. In addition, the fabrication of multicomponent ZnO-based nanocomposites with hierarchical structures is also included. Finally, the application of hierarchical ZnO nanostructures and nanocomposites in typical photocatalytic reactions, such as pollutant degradation and H2 evolution, is reviewed.

  12. Phase transition from egalitarian to hierarchical societies driven by competition between cognitive and social constraints

    CERN Document Server

    Caticha, Nestor; Vicente, Renato

    2016-01-01

    Empirical evidence suggests that social structure may have changed from hierarchical to egalitarian and back along the evolutionary line of humans. We model a society subject to competing cognitive and social navigation constraints. The theory predicts that the degree of hierarchy decreases with encephalization and increases with group size. Hence hominin groups may have been driven from a phase with hierarchical order to a phase with egalitarian structures by the encephalization during the last two million years, and back to hierarchical due to fast demographical changes during the Neolithic. The dynamics in the perceived social network shows evidence in the egalitarian phase of the observed phenomenon of Reverse Dominance. The theory also predicts for modern hunter-gatherers in mild climates a trend towards an intermediate hierarchy degree and a phase transition for harder ecological conditions. In harsher climates societies would tend to bemore egalitarian if organized in small groups but more hierarchical...

  13. A corollary discharge mechanism modulates central auditory processing in singing crickets.

    Science.gov (United States)

    Poulet, J F A; Hedwig, B

    2003-03-01

    Crickets communicate using loud (100 dB SPL) sound signals that could adversely affect their own auditory system. To examine how they cope with this self-generated acoustic stimulation, intracellular recordings were made from auditory afferent neurons and an identified auditory interneuron-the Omega 1 neuron (ON1)-during pharmacologically elicited singing (stridulation). During sonorous stridulation, the auditory afferents and ON1 responded with bursts of spikes to the crickets' own song. When the crickets were stridulating silently, after one wing had been removed, only a few spikes were recorded in the afferents and ON1. Primary afferent depolarizations (PADs) occurred in the terminals of the auditory afferents, and inhibitory postsynaptic potentials (IPSPs) were apparent in ON1. The PADs and IPSPs were composed of many summed, small-amplitude potentials that occurred at a rate of about 230 Hz. The PADs and the IPSPs started during the closing wing movement and peaked in amplitude during the subsequent opening wing movement. As a consequence, during silent stridulation, ON1's response to acoustic stimuli was maximally inhibited during wing opening. Inhibition coincides with the time when ON1 would otherwise be most strongly excited by self-generated sounds in a sonorously stridulating cricket. The PADs and the IPSPs persisted in fictively stridulating crickets whose ventral nerve cord had been isolated from muscles and sense organs. This strongly suggests that the inhibition of the auditory pathway is the result of a corollary discharge from the stridulation motor network. The central inhibition was mimicked by hyperpolarizing current injection into ON1 while it was responding to a 100 dB SPL sound pulse. This suppressed its spiking response to the acoustic stimulus and maintained its response to subsequent, quieter stimuli. The corollary discharge therefore prevents auditory desensitization in stridulating crickets and allows the animals to respond to external

  14. Neuroarchitecture of the auditory cortex in the rufous horseshoe bat (Rhinolophus rouxi).

    Science.gov (United States)

    Radtke-Schuller, S

    2001-07-01

    This study describes the location and anatomical subdivisions of the auditory cortex of the horseshoe bat, Rhinolophus rouxi. The basic cyto- and myeloarchitectural features and cytochrome oxidase reactivity patterns are evaluated in brains where auditory fields have been previously established neurophysiologically (Radtke-Schuller and Schuller 1995). Thus, the neuroanatomical findings from these brains and additional analyzed material are related to neurophysiological characteristics. The neocortex of Rhinolophus shows a typical mammalian six-layered organization. It is poorly laminated, has a low density of granular elements, a wide layer I, and a phylogenetically old pyramidal cell type in a sharply accentuated layer II. These features are generally considered 'primitive' or conservative. Frontal, parietal, temporal and occipital regions can be distinguished. In the temporal cortex, layers III and IV are found to be markedly thicker than layer V, in contrast to the parietal region, where a prominent layer V, containing a high concentration of large pyramidal cells is the most outstanding feature. The entire temporal region, most of the parietal and parts of the occipital region are responsive to auditory stimuli. The primary auditory field corresponds to most of the temporal region. The fields of the parietal region almost completely coincide with the dorsal fields of the auditory cortex. Border zones between the temporal, parietal, and occipital regions correspond to the posterior auditory field. The non-primary fields of the auditory cortex occupy a larger area of the bat's neocortex than the primary field. The accentuated neuroarchitectural features, like cortical thickness and staining intensity, are shown to coincide with the physiological representation of biologically significant parameters.

  15. Long Latency Auditory Evoked Potentials during Meditation.

    Science.gov (United States)

    Telles, Shirley; Deepeshwar, Singh; Naveen, Kalkuni Visweswaraiah; Pailoor, Subramanya

    2015-10-01

    The auditory sensory pathway has been studied in meditators, using midlatency and short latency auditory evoked potentials. The present study evaluated long latency auditory evoked potentials (LLAEPs) during meditation. Sixty male participants, aged between 18 and 31 years (group mean±SD, 20.5±3.8 years), were assessed in 4 mental states based on descriptions in the traditional texts. They were (a) random thinking, (b) nonmeditative focusing, (c) meditative focusing, and (d) meditation. The order of the sessions was randomly assigned. The LLAEP components studied were P1 (40-60 ms), N1 (75-115 ms), P2 (120-180 ms), and N2 (180-280 ms). For each component, the peak amplitude and peak latency were measured from the prestimulus baseline. There was significant decrease in the peak latency of the P2 component during and after meditation (Pmeditation facilitates the processing of information in the auditory association cortex, whereas the number of neurons recruited was smaller in random thinking and non-meditative focused thinking, at the level of the secondary auditory cortex, auditory association cortex and anterior cingulate cortex.

  16. Auditory processing in fragile x syndrome.

    Science.gov (United States)

    Rotschafer, Sarah E; Razak, Khaleel A

    2014-01-01

    Fragile X syndrome (FXS) is an inherited form of intellectual disability and autism. Among other symptoms, FXS patients demonstrate abnormalities in sensory processing and communication. Clinical, behavioral, and electrophysiological studies consistently show auditory hypersensitivity in humans with FXS. Consistent with observations in humans, the Fmr1 KO mouse model of FXS also shows evidence of altered auditory processing and communication deficiencies. A well-known and commonly used phenotype in pre-clinical studies of FXS is audiogenic seizures. In addition, increased acoustic startle response is seen in the Fmr1 KO mice. In vivo electrophysiological recordings indicate hyper-excitable responses, broader frequency tuning, and abnormal spectrotemporal processing in primary auditory cortex of Fmr1 KO mice. Thus, auditory hyper-excitability is a robust, reliable, and translatable biomarker in Fmr1 KO mice. Abnormal auditory evoked responses have been used as outcome measures to test therapeutics in FXS patients. Given that similarly abnormal responses are present in Fmr1 KO mice suggests that cellular mechanisms can be addressed. Sensory cortical deficits are relatively more tractable from a mechanistic perspective than more complex social behaviors that are typically studied in autism and FXS. The focus of this review is to bring together clinical, functional, and structural studies in humans with electrophysiological and behavioral studies in mice to make the case that auditory hypersensitivity provides a unique opportunity to integrate molecular, cellular, circuit level studies with behavioral outcomes in the search for therapeutics for FXS and other autism spectrum disorders.

  17. Auditory Processing in Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Sarah E Rotschafer

    2014-02-01

    Full Text Available Fragile X syndrome (FXS is an inherited form of intellectual disability and autism. Among other symptoms, FXS patients demonstrate abnormalities in sensory processing and communication. Clinical, behavioral and electrophysiological studies consistently show auditory hypersensitivity in humans with FXS. Consistent with observations in humans, the Fmr1 KO mouse model of FXS also shows evidence of altered auditory processing and communication deficiencies. A well-known and commonly used phenotype in pre-clinical studies of FXS is audiogenic seizures. In addition, increased acoustic startle is also seen in the Fmr1 KO mice. In vivo electrophysiological recordings indicate hyper-excitable responses, broader frequency tuning and abnormal spectrotemporal processing in primary auditory cortex of Fmr1 KO mice. Thus, auditory hyper-excitability is a robust, reliable and translatable biomarker in Fmr1 KO mice. Abnormal auditory evoked responses have been used as outcome measures to test therapeutics in FXS patients. Given that similarly abnormal responses are present in Fmr1 KO mice suggests that cellular mechanisms can be addressed. Sensory cortical deficits are relatively more tractable from a mechanistic perspective than more complex social behaviors that are typically studied in autism and FXS. The focus of this review is to bring together clinical, functional and structural studies in humans with electrophysiological and behavioral studies in mice to make the case that auditory hypersensitivity provides a unique opportunity to integrate molecular, cellular, circuit level studies with behavioral outcomes in the search for therapeutics for FXS and other autism spectrum disorders.

  18. Auditory dysfunction associated with solvent exposure

    Directory of Open Access Journals (Sweden)

    Fuente Adrian

    2013-01-01

    Full Text Available Abstract Background A number of studies have demonstrated that solvents may induce auditory dysfunction. However, there is still little knowledge regarding the main signs and symptoms of solvent-induced hearing loss (SIHL. The aim of this research was to investigate the association between solvent exposure and adverse effects on peripheral and central auditory functioning with a comprehensive audiological test battery. Methods Seventy-two solvent-exposed workers and 72 non-exposed workers were selected to participate in the study. The test battery comprised pure-tone audiometry (PTA, transient evoked otoacoustic emissions (TEOAE, Random Gap Detection (RGD and Hearing-in-Noise test (HINT. Results Solvent-exposed subjects presented with poorer mean test results than non-exposed subjects. A bivariate and multivariate linear regression model analysis was performed. One model for each auditory outcome (PTA, TEOAE, RGD and HINT was independently constructed. For all of the models solvent exposure was significantly associated with the auditory outcome. Age also appeared significantly associated with some auditory outcomes. Conclusions This study provides further evidence of the possible adverse effect of solvents on the peripheral and central auditory functioning. A discussion of these effects and the utility of selected hearing tests to assess SIHL is addressed.

  19. Speech Evoked Auditory Brainstem Response in Stuttering

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    Ali Akbar Tahaei

    2014-01-01

    Full Text Available Auditory processing deficits have been hypothesized as an underlying mechanism for stuttering. Previous studies have demonstrated abnormal responses in subjects with persistent developmental stuttering (PDS at the higher level of the central auditory system using speech stimuli. Recently, the potential usefulness of speech evoked auditory brainstem responses in central auditory processing disorders has been emphasized. The current study used the speech evoked ABR to investigate the hypothesis that subjects with PDS have specific auditory perceptual dysfunction. Objectives. To determine whether brainstem responses to speech stimuli differ between PDS subjects and normal fluent speakers. Methods. Twenty-five subjects with PDS participated in this study. The speech-ABRs were elicited by the 5-formant synthesized syllable/da/, with duration of 40 ms. Results. There were significant group differences for the onset and offset transient peaks. Subjects with PDS had longer latencies for the onset and offset peaks relative to the control group. Conclusions. Subjects with PDS showed a deficient neural timing in the early stages of the auditory pathway consistent with temporal processing deficits and their abnormal timing may underlie to their disfluency.

  20. Phonological Processing In Human Auditory Cortical Fields

    Directory of Open Access Journals (Sweden)

    David L Woods

    2011-04-01

    Full Text Available We used population-based cortical-surface analysis of functional magnetic imaging (fMRI data to characterize the processing of consonant-vowel-consonant syllables (CVCs and spectrally-matched amplitude-modulated noise bursts (AMNBs in human auditory cortex as subjects attended to auditory or visual stimuli in an intermodal selective attention paradigm. Average auditory cortical field (ACF locations were defined using tonotopic mapping in a previous study. Activations in auditory cortex were defined by two stimulus-preference gradients: (1 Medial belt ACFs preferred AMNBs and lateral belt and parabelt fields preferred CVCs. This preference extended into core ACFs with medial regions of primary auditory cortex (A1 and rostral field (R preferring AMNBs and lateral regions preferring CVCs. (2 Anterior ACFs showed smaller activations but more clearly defined stimulus preferences than did posterior ACFs. Stimulus preference gradients were unaffected by auditory attention suggesting that different ACFs are specialized for the automatic processing of different spectrotemporal sound features.

  1. Auditory model inversion and its application

    Institute of Scientific and Technical Information of China (English)

    ZHAO Heming; WANG Yongqi; CHEN Xueqin

    2005-01-01

    Auditory model has been applied to several aspects of speech signal processing field, and appears to be effective in performance. This paper presents the inverse transform of each stage of one widely used auditory model. First of all it is necessary to invert correlogram and reconstruct phase information by repetitious iterations in order to get auditory-nerve firing rate. The next step is to obtain the negative parts of the signal via the reverse process of the HWR (Half Wave Rectification). Finally the functions of inner hair cell/synapse model and Gammatone filters have to be inverted. Thus the whole auditory model inversion has been achieved. An application of noisy speech enhancement based on auditory model inversion algorithm is proposed. Many experiments show that this method is effective in reducing noise.Especially when SNR of noisy speech is low it is more effective than other methods. Thus this auditory model inversion method given in this paper is applicable to speech enhancement field.

  2. Auditory processing disorders: relationship to cognitive processes and underlying auditory neural integrity.

    Science.gov (United States)

    Allen, Prudence; Allan, Chris

    2014-02-01

    Auditory processing disorder (APD) in children has been reported and discussed in the clinical and research literature for many years yet there remains poor agreement on diagnostic criteria, the relationship between APD and cognitive skills, and the importance of assessing underlying neural integrity. The present study used a repeated measures design to examine the relationship between a clinical APD diagnosis achieved with behavioral tests used in many clinics, cognitive abilities measured with standardized tests of intelligence, academic achievement, language, phonology, memory and attention and measures of auditory neural integrity as measured with acoustic reflex thresholds and auditory brainstem responses. Participants were 63 children, 7-17 years of age, who reported listening difficulties in spite of normal hearing thresholds. Parents/guardians completed surveys about the child's auditory and attention behavior while children completed an audiologic examination that included 5 behavioral tests of auditory processing ability. Standardized tests that examined intelligence, academic achievement, language, phonology, memory and attention, and objective tests auditory function included crossed and uncrossed acoustic reflex thresholds and auditory brainstem responses (ABR) were also administered to each child. Forty of the children received an APD diagnosis based on the 5 behavioral tests and 23 did not. The groups of children performed similarly on intelligence measures but the children with an APD diagnosis tended to perform more poorly on other cognitive measures. Auditory brainstem responses and acoustic reflex thresholds were often abnormal in both groups of children. Results of this study suggest that a purely behavioral test battery may be insufficient to accurately identify all children with auditory processing disorders. Physiologic test measures, including acoustic reflex and auditory brainstem response tests, are important indicators of auditory

  3. Adult-onset juvenile xanthogranuloma of the external auditory canal: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Hur, Joon Ho; Kim, Jae Kyun; Seo, Gi Young; Choi, Woo Sun; Byun, Jun Soo; Lee, Woong Jae; Lee, Tae Jin [Chung-Ang University College of Medicine, Chung-Ang University Hospital, Seoul (Korea, Republic of); Kim, Na Ra [Dept. of Radiology, Samsung Medical Center, Sungkyunkwan University College of Medicine, Seoul (Korea, Republic of)

    2016-05-15

    Juvenile xanthogranuloma (JXG) is a benign, spontaneously regressing lesion that usually occurs during the first year of life, but may also occur in adulthood. Although the most common presentation of JXG is the cutaneous lesion, it can also manifest in various visceral organs. JXG of the external auditory canal is extremely rare, and there have been only a few reports of those cases in the English literature. In this study, we present a case of pathologically proven JXG that occurred in the external auditory canal with a symptomatic clinical presentation.

  4. Entropical Aspects in Auditory Processes and Psychoacoustical Law of Weber-Fechner

    Science.gov (United States)

    Cosma, I.; Popescu, D. I.

    For hearing sense, the mechanoreceptors fire action potentials when their membranes are physically stretched. Based on the statistical physics, we analyzed the entropical aspects in auditory processes of hearing. We develop a model that connects the logarithm of relative intensity of sound (loudness) to the level of energy disorder within the system of cellular sensory system. The increasing of entropy and disorder in the system is connected to the free energy available to signal the production of action potentials in inner hair cells of the vestibulocochlear auditory organ.

  5. HIDEN: Hierarchical decomposition of regulatory networks

    Directory of Open Access Journals (Sweden)

    Gülsoy Günhan

    2012-09-01

    Full Text Available Abstract Background Transcription factors regulate numerous cellular processes by controlling the rate of production of each gene. The regulatory relations are modeled using transcriptional regulatory networks. Recent studies have shown that such networks have an underlying hierarchical organization. We consider the problem of discovering the underlying hierarchy in transcriptional regulatory networks. Results We first transform this problem to a mixed integer programming problem. We then use existing tools to solve the resulting problem. For larger networks this strategy does not work due to rapid increase in running time and space usage. We use divide and conquer strategy for such networks. We use our method to analyze the transcriptional regulatory networks of E. coli, H. sapiens and S. cerevisiae. Conclusions Our experiments demonstrate that: (i Our method gives statistically better results than three existing state of the art methods; (ii Our method is robust against errors in the data and (iii Our method’s performance is not affected by the different topologies in the data.

  6. Hierarchical Design Method for Micro Device

    Directory of Open Access Journals (Sweden)

    Zheng Liu

    2013-05-01

    Full Text Available Traditional mask-beginning design flow of micro device is unintuitive and fussy for designers. A hierarchical design method and involved key technologies for features mapping procedure are presented. With the feature-based design framework, the model of micro device is organized by various features in different designing stages, which can be converted into each other based on the mapping rules. The feature technology is the foundation of the three-level design flow that provides a more efficient design way. In system level, functional features provide the top level of schematic and functional description. After the functional mapping procedure, on the other hand, parametric design features construct the 3D model of micro device in device level, which is based on Hybird Model representation. By means of constraint features, the corresponding revision rules are applied to the rough model to optimize the original structure. As a result, the model reconstruction algorithm makes benefit for the model revision and constraint features mapping process. Moreover, the formulating description of manufacturing features derivation provides the automatic way for model conversion.

  7. Fluorocarbon adsorption in hierarchical porous frameworks

    Science.gov (United States)

    Motkuri, Radha Kishan; Annapureddy, Harsha V. R.; Vijaykumar, M.; Schaef, H. Todd; Martin, Paul F.; McGrail, B. Peter; Dang, Liem X.; Krishna, Rajamani; Thallapally, Praveen K.

    2014-07-01

    Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity for dichlorodifluoromethane of >4 mmol g-1 at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous framework shows an exceptionally high uptake capacity reaching >14 mmol g-1 at P/Po of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption is found to generally correlate with the polarizability and boiling point of the refrigerant, with dichlorodifluoromethane >chlorodifluoromethane >chlorotrifluoromethane >tetrafluoromethane >methane. These results suggest the possibility of exploiting these sorbents for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling.

  8. Hierarchical group dynamics in pigeon flocks.

    Science.gov (United States)

    Nagy, Máté; Akos, Zsuzsa; Biro, Dora; Vicsek, Tamás

    2010-04-08

    Animals that travel together in groups display a variety of fascinating motion patterns thought to be the result of delicate local interactions among group members. Although the most informative way of investigating and interpreting collective movement phenomena would be afforded by the collection of high-resolution spatiotemporal data from moving individuals, such data are scarce and are virtually non-existent for long-distance group motion within a natural setting because of the associated technological difficulties. Here we present results of experiments in which track logs of homing pigeons flying in flocks of up to 10 individuals have been obtained by high-resolution lightweight GPS devices and analysed using a variety of correlation functions inspired by approaches common in statistical physics. We find a well-defined hierarchy among flock members from data concerning leading roles in pairwise interactions, defined on the basis of characteristic delay times between birds' directional choices. The average spatial position of a pigeon within the flock strongly correlates with its place in the hierarchy, and birds respond more quickly to conspecifics perceived primarily through the left eye-both results revealing differential roles for birds that assume different positions with respect to flock-mates. From an evolutionary perspective, our results suggest that hierarchical organization of group flight may be more efficient than an egalitarian one, at least for those flock sizes that permit regular pairwise interactions among group members, during which leader-follower relationships are consistently manifested.

  9. Hierarchical spatiotemporal matrix models for characterizing invasions.

    Science.gov (United States)

    Hooten, Mevin B; Wikle, Christopher K; Dorazio, Robert M; Royle, J Andrew

    2007-06-01

    The growth and dispersal of biotic organisms is an important subject in ecology. Ecologists are able to accurately describe survival and fecundity in plant and animal populations and have developed quantitative approaches to study the dynamics of dispersal and population size. Of particular interest are the dynamics of invasive species. Such nonindigenous animals and plants can levy significant impacts on native biotic communities. Effective models for relative abundance have been developed; however, a better understanding of the dynamics of actual population size (as opposed to relative abundance) in an invasion would be beneficial to all branches of ecology. In this article, we adopt a hierarchical Bayesian framework for modeling the invasion of such species while addressing the discrete nature of the data and uncertainty associated with the probability of detection. The nonlinear dynamics between discrete time points are intuitively modeled through an embedded deterministic population model with density-dependent growth and dispersal components. Additionally, we illustrate the importance of accommodating spatially varying dispersal rates. The method is applied to the specific case of the Eurasian Collared-Dove, an invasive species at mid-invasion in the United States at the time of this writing.

  10. [Presbycusis: neural degeneration and aging on the auditory receptor of C57/BL6J mice].

    Science.gov (United States)

    Castillo, E; Carricondo, F; Bartolomé, M V; Vicente-Torres, A; Poch Broto, J; Gil-Loyzaga, P

    2006-11-01

    Presbycusis is a progressive hearing impairment associated with aging, characterized by hearing loss and a degeneration of cochlear structures. In this paper we analyze the effects of aging on the auditory system of C57/BL6J mice, with electrophysiological and morphological studies. With this aim the auditory potentials of mice aging 1, 3, 6, 9, 12, 15, 18, 21 and 24 months were recorded, and then the morphology of the cochleal were analyzed. Auditory potentials revealed an increase in wave latencies, as well as a decrease in their amplitudes during aging. Morphological results showed a total Corti's organ degeneration, being replaced by a flat epithelial layer, and a total absence of hair cells.

  11. Membrane potential dynamics of populations of cortical neurons during auditory streaming.

    Science.gov (United States)

    Farley, Brandon J; Noreña, Arnaud J

    2015-10-01

    How a mixture of acoustic sources is perceptually organized into discrete auditory objects remains unclear. One current hypothesis postulates that perceptual segregation of different sources is related to the spatiotemporal separation of cortical responses induced by each acoustic source or stream. In the present study, the dynamics of subthreshold membrane potential activity were measured across the entire tonotopic axis of the rodent primary auditory cortex during the auditory streaming paradigm using voltage-sensitive dye imaging. Consistent with the proposed hypothesis, we observed enhanced spatiotemporal segregation of cortical responses to alternating tone sequences as their frequency separation or presentation rate was increased, both manipulations known to promote stream segregation. However, across most streaming paradigm conditions tested, a substantial cortical region maintaining a response to both tones coexisted with more peripheral cortical regions responding more selectively to one of them. We propose that these coexisting subthreshold representation types could provide neural substrates to support the flexible switching between the integrated and segregated streaming percepts.

  12. Optogenetic stimulation of the auditory pathway for research and future prosthetics.

    Science.gov (United States)

    Moser, Tobias

    2015-10-01

    Sound is encoded by spiral ganglion neurons (SGNs) in the hearing organ, the cochlea, with great temporal, spectral and intensity resolution. When hearing fails, electric stimulation by implanted prostheses can partially restore hearing. Optical stimulation promises a fundamental advance of hearing restoration over electric prostheses since light can be conveniently focused and hence might dramatically improve frequency resolution of sound encoding. Combining optogenetic manipulation of neurons with innovative optical stimulation technology promises versatile spatiotemporal stimulation patterns in the auditory system. Therefore, using optical stimulation of SGNs also has great potential for auditory research. Here, I review recent progress in optogenetic stimulation of the auditory system and its potential for future application in research and hearing restoration.

  13. Morphological and physiological regeneration in the auditory system of adult Mecopoda elongata (Orthoptera: Tettigoniidae).

    Science.gov (United States)

    Krüger, Silke; Butler, Casey S; Lakes-Harlan, Reinhard

    2011-02-01

    Orthopterans are suitable model organisms for investigations of regeneration mechanisms in the auditory system. Regeneration has been described in the auditory systems of locusts (Caelifera) and of crickets (Ensifera). In this study, we comparatively investigate the neural regeneration in the auditory system in the bush cricket Mecopoda elongata. A crushing of the tympanal nerve in the foreleg of M. elongata results in a loss of auditory information transfer. Physiological recordings of the tympanal nerve suggest outgrowing fibers 5 days after crushing. An anatomical regeneration of the fibers within the central nervous system starts 10 days after crushing. The neuronal projection reaches the target area at day 20. Threshold values to low frequency airborne sound remain high after crushing, indicating a lower regeneration capability of this group of fibers. However, within the central target area the low frequency areas are also innervated. Recordings of auditory interneurons show that the regenerating fibers form new functional connections starting at day 20 after crushing.

  14. Biomimetic Hierarchical Assembly of Helical Supraparticles from Chiral Nanoparticles.

    Science.gov (United States)

    Zhou, Yunlong; Marson, Ryan L; van Anders, Greg; Zhu, Jian; Ma, Guanxiang; Ercius, Peter; Sun, Kai; Yeom, Bongjun; Glotzer, Sharon C; Kotov, Nicholas A

    2016-03-22

    Chiroptical materials found in butterflies, beetles, stomatopod crustaceans, and other creatures are attributed to biocomposites with helical motifs and multiscale hierarchical organization. These structurally sophisticated materials self-assemble from primitive nanoscale building blocks, a process that is simpler and more energy efficient than many top-down methods currently used to produce similarly sized three-dimensional materials. Here, we report that molecular-scale chirality of a CdTe nanoparticle surface can be translated to nanoscale helical assemblies, leading to chiroptical activity in the visible electromagnetic range. Chiral CdTe nanoparticles coated with cysteine self-organize around Te cores to produce helical supraparticles. D-/L-Form of the amino acid determines the dominant left/right helicity of the supraparticles. Coarse-grained molecular dynamics simulations with a helical pair-potential confirm the assembly mechanism and the origin of its enantioselectivity, providing a framework for engineering three-dimensional chiral materials by self-assembly. The helical supraparticles further self-organize into lamellar crystals with liquid crystalline order, demonstrating the possibility of hierarchical organization and with multiple structural motifs and length scales determined by molecular-scale asymmetry of nanoparticle interactions.

  15. Auditory function in vestibular migraine

    Directory of Open Access Journals (Sweden)

    John Mathew

    2016-01-01

    Full Text Available Introduction: Vestibular migraine (VM is a vestibular syndrome seen in patients with migraine and is characterized by short spells of spontaneous or positional vertigo which lasts between a few seconds to weeks. Migraine and VM are considered to be a result of chemical abnormalities in the serotonin pathway. Neuhauser′s diagnostic criteria for vestibular migraine is widely accepted. Research on VM is still limited and there are few studies which have been published on this topic. Materials and Methods: This study has two parts. In the first part, we did a retrospective chart review of eighty consecutive patients who were diagnosed with vestibular migraine and determined the frequency of auditory dysfunction in these patients. The second part was a prospective case control study in which we compared the audiological parameters of thirty patients diagnosed with VM with thirty normal controls to look for any significant differences. Results: The frequency of vestibular migraine in our population is 22%. The frequency of hearing loss in VM is 33%. Conclusion: There is a significant difference between cases and controls with regards to the presence of distortion product otoacoustic emissions in both ears. This finding suggests that the hearing loss in VM is cochlear in origin.

  16. Hierarchically structured, nitrogen-doped carbon membranes

    KAUST Repository

    Wang, Hong

    2017-08-03

    The present invention is a structure, method of making and method of use for a novel macroscopic hierarchically structured, nitrogen-doped, nano-porous carbon membrane (HNDCMs) with asymmetric and hierarchical pore architecture that can be produced on a large-scale approach. The unique HNDCM holds great promise as components in separation and advanced carbon devices because they could offer unconventional fluidic transport phenomena on the nanoscale. Overall, the invention set forth herein covers a hierarchically structured, nitrogen-doped carbon membranes and methods of making and using such a membranes.

  17. A Model for Slicing JAVA Programs Hierarchically

    Institute of Scientific and Technical Information of China (English)

    Bi-Xin Li; Xiao-Cong Fan; Jun Pang; Jian-Jun Zhao

    2004-01-01

    Program slicing can be effectively used to debug, test, analyze, understand and maintain objectoriented software. In this paper, a new slicing model is proposed to slice Java programs based on their inherent hierarchical feature. The main idea of hierarchical slicing is to slice programs in a stepwise way, from package level, to class level, method level, and finally up to statement level. The stepwise slicing algorithm and the related graph reachability algorithms are presented, the architecture of the Java program Analyzing Tool (JATO) based on hierarchical slicing model is provided, the applications and a small case study are also discussed.

  18. Hierarchical modeling and analysis for spatial data

    CERN Document Server

    Banerjee, Sudipto; Gelfand, Alan E

    2003-01-01

    Among the many uses of hierarchical modeling, their application to the statistical analysis of spatial and spatio-temporal data from areas such as epidemiology And environmental science has proven particularly fruitful. Yet to date, the few books that address the subject have been either too narrowly focused on specific aspects of spatial analysis, or written at a level often inaccessible to those lacking a strong background in mathematical statistics.Hierarchical Modeling and Analysis for Spatial Data is the first accessible, self-contained treatment of hierarchical methods, modeling, and dat

  19. Continuum damage modeling and simulation of hierarchical dental enamel

    Science.gov (United States)

    Ma, Songyun; Scheider, Ingo; Bargmann, Swantje

    2016-05-01

    Dental enamel exhibits high fracture toughness and stiffness due to a complex hierarchical and graded microstructure, optimally organized from nano- to macro-scale. In this study, a 3D representative volume element (RVE) model is adopted to study the deformation and damage behavior of the fibrous microstructure. A continuum damage mechanics model coupled to hyperelasticity is developed for modeling the initiation and evolution of damage in the mineral fibers as well as protein matrix. Moreover, debonding of the interface between mineral fiber and protein is captured by employing a cohesive zone model. The dependence of the failure mechanism on the aspect ratio of the mineral fibers is investigated. In addition, the effect of the interface strength on the damage behavior is studied with respect to geometric features of enamel. Further, the effect of an initial flaw on the overall mechanical properties is analyzed to understand the superior damage tolerance of dental enamel. The simulation results are validated by comparison to experimental data from micro-cantilever beam testing at two hierarchical levels. The transition of the failure mechanism at different hierarchical levels is also well reproduced in the simulations.

  20. Hierarchical Heteroclinics in Dynamical Model of Cognitive Processes: Chunking

    Science.gov (United States)

    Afraimovich, Valentin S.; Young, Todd R.; Rabinovich, Mikhail I.

    Combining the results of brain imaging and nonlinear dynamics provides a new hierarchical vision of brain network functionality that is helpful in understanding the relationship of the network to different mental tasks. Using these ideas it is possible to build adequate models for the description and prediction of different cognitive activities in which the number of variables is usually small enough for analysis. The dynamical images of different mental processes depend on their temporal organization and, as a rule, cannot be just simple attractors since cognition is characterized by transient dynamics. The mathematical image for a robust transient is a stable heteroclinic channel consisting of a chain of saddles connected by unstable separatrices. We focus here on hierarchical chunking dynamics that can represent several cognitive activities. Chunking is the dynamical phenomenon that means dividing a long information chain into shorter items. Chunking is known to be important in many processes of perception, learning, memory and cognition. We prove that in the phase space of the model that describes chunking there exists a new mathematical object — heteroclinic sequence of heteroclinic cycles — using the technique of slow-fast approximations. This new object serves as a skeleton of motions reflecting sequential features of hierarchical chunking dynamics and is an adequate image of the chunking processing.