15 research outputs found

    Multi Pattern Features-Based Spoofing Detection Mechanism Using One Class Learning

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    Automatic Speaker Verification systems are prone to various voice spoofing attacks such as replays, voice conversion (VC) and speech synthesis. Malicious users can perform specific tasks such as controlling the bank account of someone, taking control of a smart home, and similar activities, by using advanced audio manipulation techniques. This study presents a Multi-Pattern Features Based Spoofing detection mechanism using the modified ResNet architecture and OC-Softmax layer to detect various LA and PA spoofing attacks. We proposed a novel Pattern features-based audio spoof detection scheme. The scheme contains three branches to evaluate different patterns on a Mel spectrogram of the audio file. This is the first work for the audio spoofing detection task using three different pattern representations of Mel spectrogram with modified ResNet architecture and OC-Softmax layer. Through the proposed network, we can extract pattern images from the Mel spectrogram and gives each of them into modified ResNet architecture. At the last step of each network, we use OC-Softmax to obtain a score for the current pattern image and then the method fuses three scores to label the input audio. Experimental results on the ASVspoof 2019 and ASVspoof 2021 corpuses show that the proposed method achieves better results in the challenges of ASVspoof 2019 than state-of-the-art methods. For example, in the logical access scenario, our model improves the tandem decision cost function and equal error rate scores by 0.06% and 2.14%, respectively, compared with state-of-the-art methods. Additionally, experiments illustrate that the proposed fused decision improved the performance of the system

    Distribution of Spoligotyping Defined Genotypic Lineages among Drug-Resistant Mycobacterium tuberculosis Complex Clinical Isolates in Ankara, Turkey

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    Background: Investigation of genetic heterogeneity and spoligotype-defined lineages of drug-resistant Mycobacterium tuberculosis clinical isolates collected during a three-year period in two university hospitals and National Tuberculosis Reference and Research Laboratory in Ankara, Turkey. Methods and Findings: A total of 95 drug-resistant M. tuberculosis isolates collected from three different centers were included in this study. Susceptibility testing of the isolates to four major antituberculous drugs was performed using proportion method on Löwenstein–Jensen medium and BACTEC 460-TB system. All clinical isolates were typed by using spoligotyping and IS6110-restriction fragment length polymorphism (RFLP) methods. Seventy-three of the 95 (76.8%) drug resistant M. tuberculosis isolates were isoniazid-resistant, 45 (47.4%) were rifampicin-resistant, 32 (33.7%) were streptomycinresistant and 31 (32.6%) were ethambutol-resistant. The proportion of multidrug-resistant isolates (MDR) was 42.1%. By using spoligotyping, 35 distinct patterns were observed; 75 clinical isolates were grouped in 15 clusters (clustering rate of 79%) and 20 isolates displayed unique patterns. Five of these 20 unique patterns corresponded to orphan patterns in th

    Treatment Outcomes of Multidrug-Resistant Tuberculosis: A Systematic Review and Meta-Analysis

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    BACKGROUND:Treatment outcomes for multidrug-resistant Mycobacterium Tuberculosis (MDRTB) are generally poor compared to drug sensitive disease. We sought to estimate treatment outcomes and identify risk factors associated with poor outcomes in patients with MDRTB. METHODOLOGY/PRINCIPAL FINDINGS:We performed a systematic search (to December 2008) to identify trials describing outcomes of patients treated for MDRTB. We pooled appropriate data to estimate WHO-defined outcomes at the end of treatment and follow-up. Where appropriate, pooled covariates were analyzed to identify factors associated with worse outcomes. Among articles identified, 36 met our inclusion criteria, representing 31 treatment programmes from 21 countries. In a pooled analysis, 62% [95% CI 57-67] of patients had successful outcomes, while 13% [9]-[17] defaulted, 11% [9]-[13] died, and 2% [1]-[4] were transferred out. Factors associated with worse outcome included male gender 0.61 (OR for successful outcome) [0.46-0.82], alcohol abuse 0.49 [0.39-0.63], low BMI 0.41[0.23-0.72], smear positivity at diagnosis 0.53 [0.31-0.91], fluoroquinolone resistance 0.45 [0.22-0.91] and the presence of an XDR resistance pattern 0.57 [0.41-0.80]. Factors associated with successful outcome were surgical intervention 1.91 [1.44-2.53], no previous treatment 1.42 [1.05-1.94], and fluoroquinolone use 2.20 [1.19-4.09]. CONCLUSIONS/SIGNIFICANCE:We have identified several factors associated with poor outcomes where interventions may be targeted. In addition, we have identified high rates of default, which likely contributes to the development and spread of MDRTB

    Inducible transcriptional activation of the human immunodeficiency virus long terminal repeat by protein kinase inhibitors.

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    The protein kinase inhibitor 2-aminopurine (2-AP) greatly stimulated expression in human promonocytes-macrophages of plasmid constructs carrying various reporter genes (chloramphenicol acetyltransferase, lacZ, firefly luciferase [luc], and Salmonella typhimurium histidinol dehydrogenase [his]) driven by the human immunodeficiency virus type 1 (HIV-1) long terminal repeat. Adenine, adenosine, and caffeine were also effective inducers, but other purine or pyrimidine derivatives were ineffective. Experiments with mutant derivatives of the HIV-1 long terminal repeat revealed no specific eukaryotic promoter elements necessary for 2-AP induction but indicated the need for some minimum combination of such elements. Induction of HIV-1-directed gene expression appeared not to require action of the transcription factor NF-kappa B. The mechanism of induction was investigated by using the luc and his genes linked to the HIV-1 long terminal repeat. 2-AP induced marked, steady rises in mRNA accumulation from both transfected and chromosomally integrated HIV-1 constructs but no increases from an endogenous gene encoding gamma-actin or glucose 6-phosphate dehydrogenase. Thus, induction is selective and not an artifact induced by transfecting DNA into cells. In run-on transcription experiments, the rates of transcription initiation of both transfected and integrated copies of the his gene increased about sixfold in cells treated with 2-AP. Thus, while increased initiation accounted for a portion of 2-AP induction, it could not cause the far greater increase in steady-state mRNA levels. 2-AP induction did not change mRNA decay rates and differed from the phorbol ester (phorbol myristate acetate)-induced activation of the protein kinase C-NF-kappa B pathway in its time course and in its requirement for new protein synthesis. Gel retardation assays showed that unlike phorbol myristate acetate induction, 2-AP induction is enhancer independent. Whereas many previous studies have implicated the activation of various protein kinases in gene induction, we here describe a mechanism of gene activation that appears to involve protein kinase inhibition as a component of the induction response

    rpoB Gene Mutations in Rifampin-Resistant Mycobacterium tuberculosis

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    Although DNA sequencing method has not been used routinely for detecting resistance of Mycobacterium tuberculosis to antituberculosis drugs, it is suggested for the investigation of gene mutations causing resistance. Using DNA sequencing (Automated Applied Biosystems), we attempted to determine mutations in the 81bp cor region (rifampin resistance determining region) of the rpoB gene in 48 Mycobacterium tuberculosis strains found to be rifampin resistant by classical phenotypic methods. Of the 48 strains, 46 (95.8%) were found to have rpo gene mutations with 13 different types while in two (4.2%) of the 48 strains, no mutations were detected. None of the strains had mutations at more than one codon. Point mutations at the 531st (52.1 %) and 526th (18.9 %) codons were frequent. The most frequent point mutation was Ser531Leu, and it was found in 21 (4398 %) of 48 strains. This is the first study from Turkey, reporting Ser522Leu point mutation in one isolate and deletion of 515th codon (ATG - Met) in two isolates

    The treatment of multidrug-resistant tuberculosis in Turkey

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    Background: We evaluated the results of treatment in 158 consecutive patients with multidrug-resistant tuberculosis who were treated at our center in Istanbul, Turkey

    An empirical investigation of the determinants of market efficiency in Borsa Istanbul

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    Following the last global financial crisis, efficiencies of stock markets have come to sight as a novel area of research. The question of what factors shape the efficiency of the stock market is naturally always of a curiosity in theory and practice. In line with the framework of this curiosity, this study examines the main determinants that play a crucial role in the efficiency of a certain stock market, Borsa Istanbul. Our study contributes to the literature by using five years and daily data belonging to both individual and institutional investors. We here aim to specify the ten determinants of market efficiency which are categorized under investor-based, market-based and country-based determinants. According to the three different regressions and VAR analysis, the results indicate the strong relationship between the market efficiency and the specified determinants such as turnover, market volatility, the share of foreign investors and interest rate
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