702 research outputs found

    A general framework for online audio source separation

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    We consider the problem of online audio source separation. Existing algorithms adopt either a sliding block approach or a stochastic gradient approach, which is faster but less accurate. Also, they rely either on spatial cues or on spectral cues and cannot separate certain mixtures. In this paper, we design a general online audio source separation framework that combines both approaches and both types of cues. The model parameters are estimated in the Maximum Likelihood (ML) sense using a Generalised Expectation Maximisation (GEM) algorithm with multiplicative updates. The separation performance is evaluated as a function of the block size and the step size and compared to that of an offline algorithm.Comment: International conference on Latente Variable Analysis and Signal Separation (2012

    Evaluation of barriers to national CO2 geological storage assessments

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    A survey to evaluate the main perceived barriers to national CO2 storage assessments was carried out in 2015, targeting countries where some Carbon dioxide Capture and Storage (CCS) activity was known or where CCS could potentially be implemented in the future. All the questionnaire respondents indicated that some level of national assessment had been achieved. In most cases, these assessments had been sufficient to allow policy makers to make informed decisions about priorities for follow-up actions. Where national storage assessments had been carried out, the major barriers had been mainly overcome through strong political and regulatory support for CCS and policies enabling access to relevant data

    Bioreduction of Cr(VI) by alkaliphilic Bacillus subtilis and interaction of the membrane groups

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    AbstractDetoxification of Cr(VI) under alkaline pH requires attention due to the alkaline nature of many effluents. An alkaliphilic gram-positive Bacillus subtilis isolated from tannery effluent contaminated soil was found to grow and reduce Cr(VI) up to 100% at an alkaline pH9. Decrease in pH to acidic range with growth of the bacterium signified the role played by metabolites (organic acids) in chromium resistance and reduction mechanism. The XPS and FT-IR spectra confirmed the reduction of Cr(VI) by bacteria into +3 oxidation state. Chromate reductase assay indicated that the reduction was mediated by constitutive membrane bound enzymes. The kinetics of Cr(VI) reduction activity derived using the monod equation proved (Ks=0.00032) high affinity of the organism to the metal. This study thus helped to localize the reduction activity at subcellular level in a chromium resistant alkaliphilic Bacillus sp

    Molecular and clinical characterization of a claudin-low subtype of gastric cancer

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    Purpose Claudin-low molecular subtypes have been identified in breast and bladder cancers and are characterized by low expression of claudins, enrichment for epithelial-to-mesenchymal transition (EMT), and tumor-initiating cell (TIC) features. We evaluated whether the claudin-low subtype also exists in gastric cancer. Materials and Methods Four hundred fifteen tumors from The Cancer Genome Atlas (TCGA) gastric cancer mRNA data set were clustered on the claudin, EMT, and TIC gene sets to identify claudin-low tumors. We derived a 24-gene predictor that classifies gastric cancer into claudin-low and non-claudin-low subtypes. This predictor was validated with the Asian Cancer Research Group(ACRG)data set. We characterized molecular and clinical features of claudin-low tumors. Results We identified 46 tumors that had consensus enrichment for claudin-low features in TCGA data set. Claudin-low tumors were most commonly diffuse histologic type (82%) and originally classified as TCGA genomically stable(GS)subtype (78%). Compared with GS subtype, claudin-low subtype had significant activation in Rho family of GTPases signaling, which appears to play a key role in its EMT and TIC properties. In the ACRG data set, 28 of 300 samples were classified as claudin-low tumors by the 24-gene predictor and were phenotypically similar to the initially derived claudin-low tumors. Clinically, claudin-low subtype had the worst overall survival. Of note, the hazard ratios that compared claudin-low versus GS subtype were 2.10 (95% CI, 1.07 to 4.11) in TCGA and 2.32 (95% CI, 1.18 to 4.55) in the ACRG cohorts, with adjustment for age and pathologic stage. Conclusion We identified a gastric claudin-low subtype that carries a poor prognosis likely related to therapeutic resistance as a result of its EMT and TIC phenotypes

    Magnetic fields in the early universe in the string approach to MHD

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    There is a reformulation of magnetohydrodynamics in which the fundamental dynamical quantities are the positions and velocities of the lines of magnetic flux in the plasma, which turn out to obey equations of motion very much like ideal strings. We use this approach to study the evolution of a primordial magnetic field generated during the radiation-dominated era in the early Universe. Causality dictates that the field lines form a tangled random network, and the string-like equations of motion, plus the assumption of perfect reconnection, inevitably lead to a self-similar solution for the magnetic field power spectrum. We present the predicted form of the power spectrum, and discuss insights gained from the string approximation, in particular the implications for the existence or not of an inverse cascade.Comment: 12 pages, 2 figure

    An opaque Sun? The potential for future, higher opacities to solve the solar abundance problem

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    Last year Bailey et al. announced their measurement of iron opacity that increases the Rosseland mean at the base of the solar convection zone by 7%. I ask what happens if the absorption by other elements is also stronger than predicted so far. Artificially increasing the absorption by other elements, proportional to the number of bound electrons in the absorber (reflecting our remaining ignorance of atomic physics) gives an opacity increase for a solar model, that has the potential to solve the long-standing solar abundance problem. Conclusion: Opacities are the likely source of the solar abundance problem, and the solar abundances are likely closer to those of Asplund et al. (2009) than to the various classic sets of abundances

    Safe surgery for glioblastoma: recent advances and modern challenges

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    One of the major challenges during glioblastoma surgery is balancing between maximizing extent of resection and preventing neurological deficits. Several surgical techniques and adjuncts have been developed to help identify eloquent areas both preoperatively (fMRI, nTMS, MEG, DTI) and intraoperatively (imaging (ultrasound, iMRI), electrostimulation (mapping), cerebral perfusion measurements (fUS)), and visualization (5-ALA, fluoresceine)). In this review, we give an update of the state-of-the-art management of both primary and recurrent glioblastomas. We will review the latest surgical advances, challenges, and approaches that define the onco-neurosurgical practice in a contemporary setting and give an overview of the current prospective scientific efforts

    Report on biological and ecological data in FFDB pilot version 1

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    Task 2.3 of work package 2 (Advancing biological knowledge and evaluation of current stock assessment models) focuses on the compilation of biological, ecological and fisheries dependent and fisheries independent data that is required for other FarFish WPs. During the first year of FarFish, some modifications in the objectives occurred, resulting in changes in the species. For example, in the Cape Verde and Seychelles CSs, the focus is now on by-catch species that are not assessed by the Regional Management Fisheries Organizations (RMFO): the International Commission for the Conservation of Atlantic Tunas (ICCAT) and the Indian Ocean Tuna Commission (IOTC). Lists of species for each CS have now been drawn up, sources of data identified, contacts have been made with RMFOs and DG MARE, and data is being compiled. Data compilation has been largely driven by the FarFish Data Base (FFDB) template developed in WP 6 (see deliverables D6.1 and D6.4). On the other hand, other data required for visualization purposes, especially time series, is also being compiled or requested. A formal data request is being prepared for DG MARE, while coastal state CS participants will be requested to provide data for the FFDB. Talks are also ongoing with RFMOs, especially CECAF, regarding data acquisition and how FarFish can contribute or add value to assessment and management. Actions that need to be taken by Task 2.3 participants include the provision of data and uploading of data to the FFDB. Task 2.3 is ongoing (Report on biological and ecological data in FFDB pilot version 2, due in Month 26 (July 31, 2019)

    Penggunaan Narkotika dikalangan Olahragawan Malaysia

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    Penelitian ini bertujuan untuk mengenalpasti penggunaan narkotika dikalangan atlet mengikut kemahiran, iaitu yang mewakili peringkat Nasional (negara), negeri, daerah dan universiti. Selain itu, ia juga untuk melihat perbezaan penggunaan narkotika dikalangan atlet berdasarkan gender. Penelitian ini menggunakan sampel 111 atlet Malaysia (Negara = 31; Negeri = 35; Daerah = 19; Universitas = 26), yang dipilih secara random semasa pertandingan olahraga antara universitas. Manakala dari segi gender, atlet lelaki adalah 66 dan atlet perempuan adalah 45. Angket Penggunaan Narkotika (Drug Use Questionnaire) digunakan dalam penelitian ini untuk mengukur tahap penggunaan narkotika. Hasil penelitian menunjukkan tujuan utama penggunaan narkotika adalah untuk menang. Selain itu, penggunaan narkotika dikalangan atlet lelaki lebih tinggi daripada perempuan. Hasil penelitian juga menunjukkan narkotika lebih tinggi diguna oleh olahragawan yang mewakili peringkat Nasional (Negara). Ahli-ahli psikologi olahraga harus memainkan peranan penting untuk menggurangkan ketagihan penggunaan narkotika dengan memberi terapi yang berkesan. Pemerintah Malaysia harus melarang olahragawan yang menggunakan narkotika terlibat dalam pertandingan olahraga
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