4,521 research outputs found
Improved Noisy Student Training for Automatic Speech Recognition
Recently, a semi-supervised learning method known as "noisy student training"
has been shown to improve image classification performance of deep networks
significantly. Noisy student training is an iterative self-training method that
leverages augmentation to improve network performance. In this work, we adapt
and improve noisy student training for automatic speech recognition, employing
(adaptive) SpecAugment as the augmentation method. We find effective methods to
filter, balance and augment the data generated in between self-training
iterations. By doing so, we are able to obtain word error rates (WERs)
4.2%/8.6% on the clean/noisy LibriSpeech test sets by only using the clean 100h
subset of LibriSpeech as the supervised set and the rest (860h) as the
unlabeled set. Furthermore, we are able to achieve WERs 1.7%/3.4% on the
clean/noisy LibriSpeech test sets by using the unlab-60k subset of LibriLight
as the unlabeled set for LibriSpeech 960h. We are thus able to improve upon the
previous state-of-the-art clean/noisy test WERs achieved on LibriSpeech 100h
(4.74%/12.20%) and LibriSpeech (1.9%/4.1%).Comment: 5 pages, 5 figures, 4 tables; v2: minor revisions, reference adde
Splice variants of DOMINO control Drosophila circadian behavior and pacemaker neuron maintenance.
Circadian clocks control daily rhythms in behavior and physiology. In Drosophila, the small ventral lateral neurons (sLNvs) expressing PIGMENT DISPERSING FACTOR (PDF) are the master pacemaker neurons generating locomotor rhythms. Despite the importance of sLNvs and PDF in circadian behavior, little is known about factors that control sLNvs maintenance and PDF accumulation. Here, we identify the Drosophila SWI2/SNF2 protein DOMINO (DOM) as a key regulator of circadian behavior. Depletion of DOM in circadian neurons eliminates morning anticipatory activity under light dark cycle and impairs behavioral rhythmicity in constant darkness. Interestingly, the two major splice variants of DOM, DOM-A and DOM-B have distinct circadian functions. DOM-A depletion mainly leads to arrhythmic behavior, while DOM-B knockdown lengthens circadian period without affecting the circadian rhythmicity. Both DOM-A and DOM-B bind to the promoter regions of key pacemaker genes period and timeless, and regulate their protein expression. However, we identify that only DOM-A is required for the maintenance of sLNvs and transcription of pdf. Lastly, constitutive activation of PDF-receptor signaling rescued the arrhythmia and period lengthening of DOM downregulation. Taken together, our findings reveal that two splice variants of DOM play distinct roles in circadian rhythms through regulating abundance of pacemaker proteins and sLNvs maintenance
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FEE -BASED ONLINE SERVICES : EXPLORING CONSUMERS’ WILLINGNESS TO PAY
Many online service businesses are beginning to charge fees for services that they used to provide for free. It is unclear whether consumers are ready to embrace this practice. This study explores consumer attitudes toward fee-based online services. The results of the study indicate that consumers’ willingness to pay for online services is likely to be influenced by their perceived value of convenience these services provide, and by the extent to which they utilize these services. While consumers appear more willing to pay for services that are qualitatively better than free services, there is also indication that the belief remains strong among many that online services that were free in the past should remain free
Observation of interlayer phonon modes in van der Waals heterostructures
We have investigated the vibrational properties of van der Waals
heterostructures of monolayer transition metal dichalcogenides (TMDs),
specifically MoS2/WSe2 and MoSe2/MoS2 heterobilayers as well as twisted MoS2
bilayers, by means of ultralow-frequency Raman spectroscopy. We discovered
Raman features (at 30 ~ 40 cm-1) that arise from the layer-breathing mode (LBM)
vibrations between the two incommensurate TMD monolayers in these structures.
The LBM Raman intensity correlates strongly with the suppression of
photoluminescence that arises from interlayer charge transfer. The LBM is
generated only in bilayer areas with direct layer-layer contact and atomically
clean interface. Its frequency also evolves systematically with the relative
orientation between of the two layers. Our research demonstrates that LBM can
serve as a sensitive probe to the interface environment and interlayer
interactions in van der Waals materials
MicroRNA-34a is a tumor suppressor in choriocarcinoma via regulation of Delta-like1
Background: Choriocarcinoma is a gestational trophoblastic tumor which causes high mortality if left untreated. MicroRNAs (miRNAs) are small non protein-coding RNAs which inhibit target gene expression. The role of miRNAs in choriocarcinoma, however, is not well understood. In this study, we examined the effect of miR-34a in choriocarcinoma.Methods: MiR-34a was either inhibited or ectopically expressed transiently in two choriocarcinoma cell lines (BeWo and JEG-3) respectively. Its actions on cell invasion, proliferation and colony formation at low cell density were examined. The miR-34a putative target Notch ligand Delta-like 1 (DLL1) was identified by adoption of different approaches including: in-silico analysis, functional luciferase assay and western blotting. Real-time quantitative polymerase chain reaction was used to quantify changes in the expression of matrix proteinase in the treated cells. To nullify the effect of miR-34a ectopic expression, we activated Notch signaling through force-expression of the Notch intracellular domain in the miR-34a force-expressed cells. In addition, we studied the importance of DLL1 in BeWo cell invasion through ligand stimulation and antibody inhibition. Furthermore, the induction in tumor formation of miR-34a-inhibited BeWo cells in SCID mice was investigated.Results: Transient miR-34a force-expression significantly suppressed cell proliferation and invasion in BeWo and JEG-3 cells. In silicon miRNA target prediction, luciferase functional assays and Western blotting analysis demonstrated that miR-34a regulated DLL1 expression in both cell lines. Although force-expression of miR-34a suppressed the expression of DLL1 and NOTCH1, the extent of suppression was higher in DLL1 than NOTCH1 in both cell lines. MiR-34a-mediated DLL1 suppression led to reduced matrix metallopeptidase 9 and urokinase-type plasminogen activator expression. The effect of miR-34a on cell invasion was partially nullified by Notch signaling activation. DLL1 ligand stimulated while anti-DLL1 antibody treatment suppressed cell invasion. Mice inoculated with BeWo cells transfected with miR-34a inhibitor had significantly larger xenografts and stronger DLL1 expression than those with cells transfected with the control inhibitor.Conclusions: MiR-34a reduced cell proliferation and invasiveness, at least, partially through its inhibitory effect on DLL1. © 2013 Pang et al.; licensee BioMed Central Ltd.published_or_final_versio
Persistent Expression Changes of Fibrosis-Related Genes in the Lung Tissues of Rats Exposed to Lunar Dust Particles
The Moon's surface is covered by a layer of fine, potential reactive dust. Lunar dust contain about 12% of very fine respirable dust (less than 3 micrometers). The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to evaluate the toxicity of Apollo moon dust in rodents to assess the health risk of dust exposures to humans. One of the particular interests in the study is to evaluate dustinduced changes of the expression of fibrosisrelated genes, and to identify specific signaling pathways involved in lunar dustinduced toxicity. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in noseonly inhalation chambers to concentrations of 0 (control air), 2.1, 6.8, 21, and 61 milligrams per cubic meters of lunar dust. Five rats per group were euthanized at 1 day, 1 week, 1 month, and 3 months after the last inhalation exposure. The bronchoalveolar lavage fluid (BALF) was collected by lavaging with phosphatebuffered saline (PBS). A zymosaninduced luminolbased chemiluminescence assay was used to assess the activity of BAL cells. The lavaged lung tissue was snap frozen in LN2 and total RNA was isolated using the Qigen RNeasy kit. The expression of 84 fibrosisrelated genes were analyzed using the RT2 Profiler PCR Array technique. The expression of 18 genes of interest were further measured using realtime PCR technique in all the samples. 10 out of 18 genes of interest showed persistently significant expression changes in the local lung tissue exposed to lunar dust, indicating a prolonged proinflammatory response. The expressions of several of these genes were dose and timedependent and were significantly correlated with other pathological parameters. The potential signaling pathways and upstream regulators were further analyzed using IPA pathway analysis tool based on the gene expression data. The data presented in this study, for the first time, explore the molecular mechanisms of lunar dust induced toxicity, contributing not only the risk assessment for future space exploration, but also understandings of the dustinduced toxicity in humans on earth
Persistent Expression Changes of Fibrosis Related Genes in the Lung Tissues of Rats Exposed to Lunar Dust Particles
The Moon's surface is covered by a layer of reactive dust, containing 1-2% of respirable fine dust (< 3 microns). The habitable area of any lunar landing vehicle would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to evaluate the toxicity of Apollo moon dust in rodents through inhalation to assess the health risk of dust exposures to humans and to identify the mechanisms and potential pathways involved in lunar dust-induced toxicity. Ccl3, Ccl12, Cxcl2, Cxcl5, Itgb8, Tnf, Ldhc, Clec4e, Bmp7, and Smad6, showed persistently significant expression changes in the lung tissue. The expression of several of these genes were dose- and time- dependent, and were significantly correlated with other pathological. Our previous data showed that no pathological changes were detected in low dose groups. However, several genes, primarily produced by lung epithelial, were significantly altered persistently in response to low-dose dust exposure. The data presented in this study, for the first time, explores the molecular mechanisms of lunar dust induced toxicity, contributing not only the risk assessment for future space exploration, but also understandings of the dust-induced toxicity to humans on earth
Signaling Pathways Involved in Lunar Dust Induced Cytotoxicity
The Moon's surface is covered by a layer of fine, reactive dust. Lunar dust contain about 1-2% of very fine dust (< 3 micron), that is respirable. The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to evaluate the toxicity of Apollo moon dust in rodents to assess the health risk of dust exposures to humans. One of the particular interests in the study is to evaluate dust-induced changes of the expression of fibrosis-related genes, and to identify specific signaling pathways involved in lunar dust-induced toxicity. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose-only inhalation chambers to concentrations of 0 (control air), 2.1, 6.1, 21, and 61 mg/m(exp 3) of lunar dust. Five rats per group were euthanized 1 day, 1 week, 1 month, and 3 months after the last inhalation exposure. The total RNAs were isolated from the blood or lung tissue after being lavaged, using the Qigen RNeasy kit. The Rat Fibrosis RT2 Profile PCR Array was used to profile the expression of 84 genes relevant to fibrosis. The genes with significant expression changes are identified and the gene expression data were further analyzed using IPA pathway analysis tool to determine the signaling pathways with significant changes
Corporate social responsibility disclosures in international construction business: trends and prospects
There is increasing sophistication in corporate social responsibility (CSR) disclosures by international construction companies (ICCs). Nevertheless, a systematic analysis of the trends and prospects is yet to appear. This study fills that knowledge gap by providing an understanding of the idiosyncrasies of CSR disclosure and by offering suggestions for future reporting exercises. By examining the top fifty ICCs’ CSR/sustainability reports using content analysis, it found that the more negative impacts a company may have, the more remedial strategies it will disclose in a CSR report. ICCs from economically more developed countries maintain a high level of CSR disclosure, while their counterparts from developing countries have caught up in this CSR cause. As a way to improve the consistency and integrity of disclosed information, ICCs are increasingly adopting CSR reporting guidance frameworks and using third-party assurances. CSR disclosures present a high degree of uniformity while they also show nuanced and intriguing diversity. This research helps understand comprehensively the trends of CSR disclosure in international construction. It will help ICCs extrapolate their future CSR reporting exercises.postprin
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