5,784 research outputs found
Expertise with non-speech 'auditory Greebles' recruits speech-sensitive cortical regions
Regions of the human temporal lobe show greater activation for speech than for other sounds. These differences may reflect intrinsically specialized domain-specific adaptations for processing speech, or they may be driven by the significant expertise we have in listening to the speech signal. To test the expertise hypothesis, we used a video-game-based paradigm that tacitly trained listeners to categorize acoustically complex, artificial nonlinguistic sounds. Before and after training, we used functional MRI to
measure how expertise with these sounds modulated temporal lobe activation. Participants’ ability to explicitly categorize the nonspeech sounds predicted the change in pretraining to posttraining activation in speech-sensitive regions of the left posterior superior temporal sulcus, suggesting that emergent auditory expertise may help drive this functional regionalization. Thus, seemingly domain-specific patterns of neural activation in higher cortical regions may be driven in part by experience-based
restructuring of high-dimensional perceptual space
The role of the left head of caudate in suppressing irrelevant words
Suppressing irrelevant words is essential to successful speech production and is expected to involve general control mechanisms that reduce interference from task-unrelated processing. To investigate the neural mechanisms that suppress visual word interference, we used fMRI and a Stroop task, using a block design with an event-related analysis. Participants indicated with a finger press whether a visual stimulus was colored pink or blue. The stimulus was either the written word "BLUE," the written word "PINK," or a string of four Xs, with word interference introduced when the meaning of the word and its color were "incongruent" (e.g., BLUE in pink hue) relative to congruent (e.g., BLUE in blue) or neutral (e.g., XXXX in pink). The participants also made color decisions in the presence of spatial interference rather than word interference (i.e., the Simon task). By blocking incongruent, congruent, and neutral trials, we identified activation related to the mechanisms that suppress interference as that which was greater at the end relative to the start of incongruency. This highlighted the role of the left head of caudate in the control of word interference but not spatial interference. The response in the left head of caudate contrasted to bilateral inferior frontal activation that was greater at the start than at the end of incongruency, and to the dorsal anterior cingulate gyrus which responded to a change in the motor response. Our study therefore provides novel insights into the role of the left head of caudate in the mechanisms that suppress word interference
The magnetic reorientation transition in thin ferromagnetic films treated by many-body Green's function theory
This contribution describes the reorientation of the magnetization of thin
ferromagnetic Heisenberg films as function of the temperature and/or an
external field. Working in a rotating frame allows an exact treatment of the
single-ion anisotropy when going to higher-order Green's functions. Terms due
to the exchange interaction are treated by a generalized Tyablikov (RPA)
decoupling.Comment: 9 pages, 2 figure
Herschel and ALMA Observations of Massive SZE-selected Clusters
We present new Herschel observations of four massive, Sunyaev-Zel'dovich
Effect (SZE)-selected clusters at , two of which have also
been observed with ALMA. We detect 19 Herschel/PACS counterparts to
spectroscopically confirmed cluster members, five of which have redshifts
determined via CO() and [CI]() lines. The mean [CI]/CO
line ratio is in brightness temperature units, consistent with
previous results for field samples. We do not detect significant stacked ALMA
dust continuum or spectral line emission, implying upper limits on mean
interstellar medium (H + HI) and molecular gas masses. An apparent
anticorrelation of with clustercentric radius is driven by the tight
relation between star formation rate and stellar mass. We find average specific
star formation rate log(sSFR/yr) = -10.36, which is below the SFR
correlation measured for field galaxies at similar redshifts. The fraction of
infrared-bright galaxies (IRBGs; ) per cluster
and average sSFR rise significantly with redshift. For CO detections, we find
, comparable to those of field galaxies, and gas depletion
timescales of about 2 Gyr. We use radio observations to distinguish active
galactic nuclei (AGNs) from star-forming galaxies. At least four of our 19
Herschel cluster members have , implying an AGN fraction for our PACS-selected sample.Comment: Accepted in ApJ, 46 pages, 13 figure
Progressive promoter element combinations classify conserved orthogonal plant circadian gene expression modules
We aimed to test the proposal that progressive combinations of multiple promoter elements acting in concert may be responsible for the full range of phases observed in plant circadian output genes. In order to allow reliable selection of informative phase groupings of genes for our purpose, intrinsic cyclic patterns of expression were identified using a novel, non-biased method for the identification of circadian genes. Our non-biased approach identified two dominant, inherent orthogonal circadian trends underlying publicly available microarray data from plants maintained under constant conditions. Furthermore, these trends were highly conserved across several plant species. Four phase-specific modules of circadian genes were generated by projection onto these trends and, in order to identify potential combinatorial promoter elements that might classify genes into these groups, we used a Random Forest pipeline which merged data from multiple decision trees to look for the presence of element combinations. We identified a number of regulatory motifs which aggregated into coherent clusters capable of predicting the inclusion of genes within each phase module with very high fidelity and these motif combinations changed in a consistent, progressive manner from one phase module group to the next, providing strong support for our hypothesis
Growth-related quantitative trait loci in domestic and wild rainbow trout (Oncorhynchus mykiss)
Background: Somatic growth is a complex process that involves the action and interaction of genes and environment. A number of quantitative trait loci (QTL) previously identified for body weight and condition factor in rainbow trout (Oncorhynchus mykiss), and two other salmonid species, were used to further investigate the genetic architecture of growth-influencing genes in this species. Relationships among previously mapped candidate genes for growth and their co-localization to identified QTL regions are reported. Furthermore, using a comparative genomic analysis of syntenic rainbow trout linkage group clusters to their homologous regions within model teleost species such as zebrafish, stickleback and medaka, inferences were made regarding additional possible candidate genes underlying identified QTL regions.Results: Body weight (BW) QTL were detected on the majority of rainbow trout linkage groups across 10 parents from 3 strains. However, only 10 linkage groups (i.e., RT-3, -6, -8, -9, -10, -12, -13, -22, -24, -27) possessed QTL regions with chromosome-wide or genome-wide effects across multiple parents. Fewer QTL for condition factor (K) were identified and only six instances of co-localization across families were detected (i.e. RT-9, -15, -16, -23, -27, -31 and RT-2/9 homeologs). Of note, both BW and K QTL co-localize on RT-9 and RT-27. The incidence of epistatic interaction across genomic regions within different female backgrounds was also examined, and although evidence for interaction effects within certain QTL regions were evident, these interactions were few in number and statistically weak. Of interest, however, was the fact that these predominantly occurred within K QTL regions. Currently mapped growth candidate genes are largely congruent with the identified QTL regions. More QTL were detected in male, compared to female parents, with the greatest number evident in an F 1male parent derived from an intercross between domesticated and wild strain of rainbow trout which differed strongly in growth rate.Conclusions: Strain background influences the degree to which QTL effects are evident for growth-related genes. The process of domestication (which primarily selects faster growing fish) may largely reduce the genetic influences on growth-specific phenotypic variation. Although heritabilities have been reported to be relatively high for both BW and K growth traits, the genetic architecture of K phenotypic variation appears less defined (i.e., fewer major contributing QTL regions were identified compared with BW QTL regions)
On the emergent Semantic Web and overlooked issues
The emergent Semantic Web, despite being in its infancy, has already received a lotof attention from academia and industry. This resulted in an abundance of prototype systems and discussion most of which are centred around the underlying infrastructure. However, when we critically review the work done to date we realise that there is little discussion with respect to the vision of the Semantic Web. In particular, there is an observed dearth of discussion on how to deliver knowledge sharing in an environment such as the Semantic Web in effective and efficient manners. There are a lot of overlooked issues, associated with agents and trust to hidden assumptions made with respect to knowledge representation and robust reasoning in a distributed environment. These issues could potentially hinder further development if not considered at the early stages of designing Semantic Web systems. In this perspectives paper, we aim to help engineers and practitioners of the Semantic Web by raising awareness of these issues
Density Mediated Drug Release From Dapivirine Vaginal Rings Produced by Additive Manufacturing
Background: Droplet deposition modelling (DDM) is a form of 3D printing that fuses droplets of molten polymer to create each layer, providing exquisite levels of control over an object‘s design and morphology. Such manipulation allows properties including density, geometry and surface area to be manipulated in ways that have been unthinkable using conventional thermoplastic processing techniques. Here we utilise the DDM process and compare this to injection moulding to produce dapivirine (DPV) loaded vaginal rings using a pharmaceutically relevant, life science grade thermoplastic polyurethane.Methods: Vaginal rings (54.0 mm outer diameter, 4.0 mm cross sectional diameter) were fabricated by injection molding or Arburg Plastic Freeforming - a proprietary DDM process, using a hydrophobic TPU loaded with 10% w/w dapivirine. Using the DDM process, rings of 100, 50 and 10% matrix density were produced. Rings were evaluated for in vitro drug release over 29 days in an aqueous release media and assessed for thermal characteristics. Results: Daily DPV release from all ring designs ranged between 387 - 8666 μg (Day 1) and 193 - 992 μg on Day 29. DDM printed VRs with 10% infill density (68 mg DPV load) exhibited a seven fold increase in DPV release rate compared to injection molded rings containing 190 mg DPV. For DDM printed rings, there was very significant correlation between decreasing ring density and increasing DPV release rate as a percentage of total drug loading. Thermal analysis showed that the DPV melt endotherm was absent from TPU + 10% w/w DPV, suggesting that DPV was fully solubilised within the TPU at the experimental conditions.Conclusions: DDM printing on an Arburg Freeformer has been shown to create vaginal rings with a range of densities and has provided a new potential to either increase the release rate of poorly water soluble compounds or reduce the loading required to maintain a desired release rate
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