English vowel identification in quiet and noise: effects of listeners’ native language background

Purpose: To investigate the effect of listener’s native language (L1) and the types of noise on English vowel identification in noise.Method: Identification of twelve English vowels was measured in quiet and in long-term speech-shaped noise and multi-talker babble noise for English- (EN), Chinese- (CN) and Korean-native (KN) listeners at various signal-to-noise ratios.Results: Compared to non-native listeners, EN listeners performed significantly better in quiet and in noise. Vowel identification in long-term speech-shaped noise and in multi-talker babble noise was similar between CN and KN listeners. This is different from our previous study in which KN listeners performed better than CN listeners in English sentence recognition in multi-talker babble noise. Discussion: Results from the current study suggest that depending on speech materials, the effect of non-native listeners’ L1 on speech perception in noise may be different. That is, in the perception of speech materials with little linguistic cues like isolated vowels, the characteristics of non-native listener’s native language may not play a significant role. On the other hand, in the perception of running speech in which listeners need to use more linguistic cues (e.g., acoustic-phonetic, semantic, and prosodic cues), the non-native listener’s native language background might result in a different masking effect

Categorical Perception of Lexical Tones in Mandarin-speaking Congenital Amusics

Previous research suggests that within Mandarin-speaking congenital amusics, only a subgroup has behavioral lexical tone perception impairments (tone agnosia), whereas the rest of amusics do not. The purpose of the current study was to investigate the categorical nature of lexical tone perception in Mandarin-speaking amusics with and without behavioral lexical tone deficits. Three groups of listeners (controls, pure amusics and amusics with tone agnosia) participated in tone identification and discrimination tasks. Indexes of the categorical perception of a physical continuum of fundamental frequencies ranging from a rising to level tone were measured. Specifically, the stimulus durations were manipulated at 100 and 200 ms. For both stimulus durations, all groups exhibited similar categorical boundaries. The pure amusics showed sharp identification slopes and significantly peaked discrimination functions similar to those of normal controls. However, such essential characteristics for the categorical perception of lexical tones were not observed in amusics with tone agnosia. An enlarged step-size from 20 Hz to 35 Hz was not able to produce any discrimination peaks in tone agnosics either. The current study revealed that only amusics with tone agnosia showed a lack of categorical tone perception, while the pure amusics demonstrated typical categorical perception of lexical tones, indicating that the deficit of pitch processing in music does not necessarily result in the deficit in the categorical perception of lexical tones. The different performance between congenital amusics with and without tone agnosia provides a new perspective on the proposition of the relationship between music and speech perception

Classification of Five-Second Epileptic EEG Recordings Using Distribution Entropy and Sample Entropy

Epilepsy is an electrophysiological disorder of the brain, the hallmark of which is recurrent and unprovoked seizures. Electroencephalogram (EEG) measures electrical activity of the brain that is commonly applied as a non-invasive technique for seizure detection. Although a vast number of publications have been published on intelligent algorithms to classify interictal and ictal EEG, it remains an open question whether they can be detected using short-length EEG recordings. In this study, we proposed three protocols to select 5 s EEG segment for classifying interictal and ictal EEG from normal. We used the publicly-accessible Bonn database, which consists of normal, interical, and ictal EEG signals with a length of 4,097 sampling points (23.6 s) per record. In this study, we selected three segments of 868 points (5 s) length from each recordings and evaluated results for each of them separately. The well-studied irregularity measure – sample entropy (SampEn) – and a more recently proposed complexity measure – distribution entropy (DistEn) – were used as classification features. A total of 20 combinations of input parameters m and τ for the calculation of SampEn and DistEn were selected for compatibility. Results showed that SampEn was undefined for half of the used combinations of input parameters and indicated a large intra-class variance. Moreover, DistEn performed robustly for short-length EEG data indicating relative independence from input parameters and small intra-class fluctuations. In addition, it showed acceptable performance for all three classification problems (interictal EEG from normal, ictal EEG from normal, and ictal EEG from interictal) compared to SampEn, which showed better results only for distinguishing normal EEG from interictal and ictal. Both SampEn and DistEn showed good reproducibility and consistency, as evidenced by the independence of results on analysing protocol

Metabolic investigation in Gluconacetobacter xylinus and its bacterial cellulose production under a direct current electric field

The effects of a direct current (DC) electric field on the growth and metabolism of Gluconacetobacter xylinus were investigated in static culture. When a DC electric field at 10 mA was applied using platinum electrodes to the culture broth, bacterial cellulose (BC) production was promoted in 12 hours (h) but was inhibited in the last 12 h as compared to the control (without DC electric field). At the cathode, the presence of the hydrogen generated a strong reductive environment that is beneficial to cell growth. As compared to the control, the activities of glycolysis and tricarboxylic acid cycle, as well as BC productivity were observed to be slightly higher in the first 12 h. However, due to the absence of sufficient oxygen, lactic acid was accumulated from pyruvic acid at 18 h, which was not in favor of BC production. At the anode, DC inhibited cell growth in 6 h when compared to the control. The metabolic activity in G. xylinus was inhibited through the suppression of the tricarboxylic acid cycle and glycolysis. At 18-24 h, cell density was observed to decrease, which might be due to the electrolysis of water that significantly dropped the pH of cultural broth far beyond the optimal range. Meanwhile, metabolites for self-protection were accumulated, for instance proline, glutamic acid, gluconic acid and fatty acids. Notably, the accumulation of gluconic acid and lactic acid made it a really tough acid stress to cells at the anode and finally led to depression of cell growth

Polynucleotide phosphorylase regulates multiple virulence factors and the stabilities of small RNAs RsmY/Z in Pseudomonas aeruginosa

Post-transcriptional regulation enables bacteria to quickly response to environmental stresses. Polynucleotide phosphorylase (PNPase), which contains an N-terminal catalytic core and C-terminal RNA binding KH-S1 domains, is involved in RNA processing. Here we demonstrate that in Pseudomonas aeruginosa the KH-S1 domains of PNPase are required for the type III secretion system (T3SS) and bacterial virulence. Transcriptome analysis revealed a pleiotropic role of PNPase in gene regulation. Particularly, the RNA level of exsA was decreased in the ΔKH-S1 mutant, which was responsible for the reduced T3SS expression. Meanwhile, the pilus biosynthesis genes were down regulated and the type VI secretion system (T6SS) genes were up regulated in the ΔKH-S1 mutant, which were caused by increased levels of small RNAs, RsmY and RsmZ. Further studies revealed that deletion of the KH-S1 domains did not affect the transcription of RsmY/Z, but increased their stabilities. An in vivo pull-down and in vitro electrophoretic mobility shift assay (EMSA) demonstrated a direct interaction between RsmY/Z and the KH-S1 fragment. Overall, this study reveals the roles of PNPase in the regulation of virulence factors and stabilities of small RNAs in P. aeruginosa

Development and identification of SSR markers associated with starch properties and β-carotene content in the storage root of sweet potato (Ipomoea batatas L.)

Sweet potato (Ipomoea batatas L.) is a nutritious food crop and, based on the high starch content of its storage root, a potential bioethanol feedstock. Enhancing the nutritional value and starch quantity of storage roots are important goals of sweet potato breeding programs aimed at developing improved varieties for direct consumption, processing, and industrial uses. However, developing improved lines of sweet potato is challenging due to the genetic complexity of this plant and the lack of genome information. Short sequence repeat (SSR) markers are powerful molecular tools for tracking important loci in crops and for molecular-based breeding strategies; however, few SSR markers and marker-trait associations have hitherto been identified in sweet potato. In this study, we identified 1,824 SSRs by using a de novo assembly of publicly available ESTs and mRNAs in sweet potato, and designed 1,476 primer pairs based on SSR-containing sequences. We mapped 214 pairs of primers in a natural population comprised of 239 germplasms, and identified 1,278 alleles with an average of 5.972 alleles per locus and a major allele frequency of 0.7702. Population structure analysis revealed two subpopulations in this panel of germplasms, and phenotypic characterization demonstrated that this panel is suitable for association mapping of starch-related traits. We identified 32, 16, and 17 SSR markers associated with starch content, β-carotene content, and starch composition in the storage root, respectively, using association analysis and further evaluation of a subset of sweet potato genotypes with various characteristics. The SSR markers identified here can be used to select varieties with desired traits and to investigate the genetic mechanism underlying starch and carotenoid formation in the starchy roots of sweet potato

Immunization with Individual Proteins of the Lrp/AsnC Family Induces Protection Against Brucella melitensis 16M Challenges in Mice

Brucellosis is one of the most common zoonoses worldwide. Subunit vaccines are promising for the prevention of human brucellosis. In our previous protective antigen screening studies, we identified a new protective antigen, BMEI0357, which belongs to the Lrp/asnC protein family, a conserved transcriptional regulator in bacteria that is absent in eukaryotes. In the present study, the Brucella genome annotation was screened and a total of 6 proteins were identified as members of the Lrp/AsnC family. Lrp/AsnC proteins have 2 domains that are conserved among the family members. However, sequence similarities between these proteins ranged from 9% to 50%, indicating high sequence heterogeneity. To test whether proteins of this family have similar characteristics, all 6 proteins were cloned and expressed in Escherichia coli. The recombinant proteins were purified and their protective efficacy was evaluated in BALB/c mice challenged with Brucella melitensis 16M. The results show that all 6 Lrp/AsnC proteins could induce a protective immune response against Brucella melitensis 16M. Antibodies against the Lrp/AsnC proteins were detected in the immunized mice. However, levels of antibodies against these proteins were relatively variable in human brucellosis sera. Taken together, our results show that these 6 proteins of the Lrp/AsnC family in Brucella could induce protective immune responses in mice

Prevalence and Detection of Stenotrophomonas maltophilia Carrying Metallo-β-lactamase blaL1 in Beijing, China

Intrinsic β-lactam resistance in Stenotrophomonas maltophilia S. maltophilia is caused by blaL1 and/or blaL2, a kind of metallo-β-lactamase with a broad substrate spectrum including carbapenems. A rapid and sensitive molecular method for the detection of blaL1 in clinical samples is needed to guide therapeutic treatment. In present study, we first described a loop-mediated isothermal amplification (LAMP) method for the rapid detection of blaL1 in clinical samples by using two methods including a chromogenic method using calcein/Mn2+ complex and the real-time turbidity monitoring to assess the reaction. Then dissemination of L1-producing S. maltophilia was investigated from ICU patients in three top hospital in Beijing, China. The results showed that both methods detected the target DNA within 60 min under 65°C. The detection limit of LAMP was 3.79 pg/µl DNA, and its sensitivity 100-fold greater than that of conventional PCR. All 21 test strains except for S. maltophilia were negative for blaL1, indicative of the high-specificity of the primers for the blaL1. A total of 22 L1-positive isolates were identified for LAMP-based surveillance of blaL1 from 105 ICU patients with clinically suspected multi-resistant infections. The sequences of these blaL1 genes were conservative with only a few sites mutated, and the strains had highly resistant to β-lactam antibiotics. The MLST recovered that 22 strains belonged to seven different ST types. Furthermore, co-occurrence of blaL1 and blaL2 genes were detected in all of isolates. Strikingly, S. maltophilia DCPS-01 was recovered to contain blaL1, blaL2, and blaNDM‑1 genes, possessing an ability to hydrolyse all β-lactams antibiotics. Our data showed the diversity types of S. maltophilia carrying blaL1 and co-occurrence of many resistant genes in the clinical strains signal an ongoing and fast evolution of S. maltophilia resulting from their wide spread in the respiratory infections, and therefore will be difficult to control

Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo

Advanced LIGO and Advanced Virgo are monitoring the sky and collecting gravitational-wave strain data with sufficient sensitivity to detect signals routinely. In this paper we describe the data recorded by these instruments during their first and second observing runs. The main data products are gravitational-wave strain time series sampled at 16384 Hz. The datasets that include this strain measurement can be freely accessed through the Gravitational Wave Open Science Center at http://gw-openscience.org, together with data-quality information essential for the analysis of LIGO and Virgo data, documentation, tutorials, and supporting software