559 research outputs found

    Open-Set Speaker Identification under Mismatch Conditions

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    Full text of this paper is not available in the UHRA.This paper presents investigations into the performance of open-set, text-independent speaker identification (OSTI-SI) under mismatched data conditions. The scope of the study includes attempts to reduce the adverse effects of such conditions through the introduction of a modified parallel model combination (PMC) method together with condition-adjusted T-Norm (CT-Norm) into the OSTI-SI framework. The experiments are conducted using examples of real world noise. Based on the outcomes, it is demonstrated that the above approach can lead to considerable improvements in the accuracy of open-set speaker identification operating under severely mismatched data conditions. The paper details the realisation of the modified PMC method and CT-Norm in the context of OSTI-SI, presents the experimental investigations and provides an analysis of the results.otherPeer reviewe

    CLASSIFICATION OF RISK IN PSYCHIATRY

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    Psychiatric risk-assessments generally quantify risk using broad, categorical, indicators (e.g., high-risk, low-risk). We examined reliability of such indicators when applied by mental-health professionals. Four versions of a questionnaire were used, each specifying a different clinical outcome along with a range of different probabilities at which that outcome might occur. Respondents classified each probability, allowing a comparison of the level of likelihood at which different professionals would apply the terms \u27high-risk\u27, \u27medium-risk\u27 and \u27low-risk\u27. We found little consistency among professionals who assessed risk for the same outcomes. Moreover, there were also large and unpredicted differences in response-profiles between the 4 clinical outcomes. These findings raise concerns about the communication value of current risk-assessment terminology

    TIA-1 RRM23 binding and recognition of target oligonucleotides

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    TIA-1 (T-cell restricted intracellular antigen-1) is an RNA-binding protein involved in splicing and translational repression. It mainly interacts with RNA via its second and third RNA recognition motifs (RRMs), with specificity for U-rich sequences directed by RRM2. It has recently been shown that RRM3 also contributes to binding, with preferential binding for C-rich sequences. Here we designed UC-rich and CU-rich 10-nt sequences for engagement of both RRM2 and RRM3 and demonstrated that the TIA-1 RRM23 construct preferentially binds the UC-rich RNA ligand (5΄-UUUUUACUCC-3΄). Interestingly, this binding depends on the presence of Lys274 that is C-terminal to RRM3 and binding to equivalent DNA sequences occurs with similar affinity. Small-angle X-ray scattering was used to demonstrate that, upon complex formation with target RNA or DNA, TIA-1 RRM23 adopts a compact structure, showing that both RRMs engage with the target 10-nt sequences to form the complex. We also report the crystal structure of TIA-1 RRM2 in complex with DNA to 2.3 Å resolution providing the first atomic resolution structure of any TIA protein RRM in complex with oligonucleotide. Together our data support a specific mode of TIA-1 RRM23 interaction with target oligonucleotides consistent with the role of TIA-1 in binding RNA to regulate gene expressio

    Functional relevance of nonsynonymous mutations in the HIV-1 tat gene within an epidemiologically-linked transmission cohort

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    Here we investigated the nature and functional consequences of mutations in the HIV-1 tat gene within an epidemiologically-linked AIDS transmission cohort consisting of a non-progressing donor (A) and two normal progressing recipients (B and C). Multiple nonsynonymous mutations in the tat first exon were observed across time in all individuals. Some mutations demonstrated striking host specificity despite the cohort being infected with a common virus. Phylogenetic segregation of the tat clones at the time of progression to AIDS was also observed especially in recipient C. Tat clones supporting high levels of transactivation were present at all time points in all individuals, although a number of clones defective for transactivation were observed for recipient C in later time points. Here we show that the tat quasispecies in a linked transmission cohort diversify and evolve independently between hosts following transmission. It supports the belief that quasispecies variation in HIV-1 is a mechanism for selection towards defining a fitter gene variant that is capable of resisting the human immune system

    PrPC Controls via Protein Kinase A the Direction of Synaptic Plasticity in the Immature Hippocampus

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    The cellular form of prion protein PrPC is highly expressed in the brain, where it can be converted into its abnormally folded isoform PrPSc to cause neurodegenerative diseases. Its predominant synaptic localization suggests a crucial role in synaptic signaling. Interestingly, PrPC is developmentally regulated and its high expression in the immature brain could be instrumental in regulating neurogenesis and cell proliferation. Here, PrPC-deficient (Prnp0/0) mice were used to assess whether the prion protein is involved in synaptic plasticity processes in the neonatal hippocampus. To this aim, calcium transients associated with giant depolarizing potentials, a hallmark of developmental networks, were transiently paired with mossy fiber activation in such a way that the two events were coincident. While this procedure caused long-term potentiation (LTP) in wild-type (WT) animals, it caused long-term depression (LTD) in Prnp0/0 mice. Induction of LTP was postsynaptic and required the activation of cAMP-dependent protein kinase A (PKA) signaling. The induction of LTD was presynaptic and relied on G-protein-coupled GluK1 receptor and protein lipase C. In addition, at emerging CA3-CA1 synapses in WT mice, but not in Prnp0/0 mice, pairing Schaffer collateral stimulation with depolarization of CA1 principal cells induced LTP, known to be PKA dependent. Postsynaptic infusion of a constitutively active isoform of PKA catalytic subunit C\u3b1 into CA1 and CA3 principal cells in the hippocampus of Prnp0/0 mice caused a persistent synaptic facilitation that was occluded by subsequent pairing. These data suggest that PrPC plays a crucial role in regulating via PKA synaptic plasticity in the developing hippocampus. \ua9 2013 the authors

    Problems of identification among species of sardinella

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    In spite of several recent studies, confusion still surrounds on the identification of few Indian clupeoids sucfi as Sardinella, llisha and Thryssa because of their morphological similarity between species, which has severely restricted the useful biological studies CBabu Rao, 1962; Whitehead, 1973; Ramaiyan and Whitehead, 1975; and Wongratana, 1983). Of all the clupeids. the identification of the species of Sardinella by various authors based on meristic and morphomairic characters is often confusing. The identity of S. longiceps, S clupeoids, S. leiogaster, S. sirm based on few meristic and morphometric characters is relatively easy however, the same characters are not satisfactory for S. albelia. S. brachysoma, S. dayi, S. fimbriata, S. gibbosa, S. melanura and S. sirtdensis
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