Defending Adversarial Attacks on Cloud-aided Automatic Speech Recognition Systems

With the advancement of deep learning based speech recognition technology, an increasing number of cloud-aided automatic voice assistant applications, such as Google Home, Amazon Echo, and cloud AI services, such as IBM Watson, are emerging in our daily life. In a typical usage scenario, after keyword activation, the user's voice will be recorded and submitted to the cloud for automatic speech recognition (ASR) and then further action(s) might be triggered depending on the user's command(s). However, recent researches show that the deep learning based systems could be easily attacked by adversarial examples. Subsequently, the ASR systems are found being vulnerable to audio adversarial examples. Unfortunately, very few works about defending audio adversarial attack are known in the literature. Constructing a generic and robust defense mechanism to resolve this issue remains an open problem. In this work, we propose several proactive defense mechanisms against targeted audio adversarial examples in the ASR systems via code modulation and audio compression. We then show the effectiveness of the proposed strategies through extensive evaluation on natural dataset

Effects of Inorganic Passivators on Gas Production and Heavy Metal Passivation Performance during Anaerobic Digestion of Pig Manure and Corn Straw

The treatment of livestock manure caused by the expansion of the breeding industry in China has attracted wide attention. Heavy metals in pig manure can pollute soil and water and even transfer to crops, posing harm to humans through the food chain. In this study, corn straw was selected as the additive and introduced into the anaerobic digestion. Sepiolite (SE), ferric oxide (Fe2O3), attapulgite (AT) and ferric sulfate (FeSO4) were used as passivators to compare the effects of these inorganic passivators on gas production and passivation of heavy metals during the process of the anaerobic digestion. When the dry mass ratio of pig manure to straw is 8:2, the gas production efficiency is optimal. SE, AT and ferric sulfate have a much stronger ability to improve gas production performance than Fe2O3. The total gas production increased by 10.34%, 6.62% and 4.56%, and the average methane production concentration increased by 0.7%, 0.3% and 0.4%, respectively. The influence of SE, AT and ferric sulfate on the passivation of heavy metals is much better than Fe2O3, and the fractions in biological effective forms of Cu and Zn reduced by 41.87 and 19.32%, respectively. The anaerobic digestion of mixed materials is conducive to the gas production and the passivation of heavy metals. Therefore, SE, AT and ferric sulfate are selected as composite passivators, and the optimal ratio of inorganic composite passivators i: AT 7.5 g/L, ferric sulfate 5 g/L and SE 7.5 g/L, according to the results of orthogonal experiments. This study can provide a theoretical basis for the safe application of biogas fertilizers

Comparative transcriptome analysis reveals mechanisms of restriction feeding on lipid metabolism in ducks

ABSTRACT: Presently, excessive fat deposition is the main reason to limit the development of duck industry. In the production, the methods of restricted feeding (RF) were widely used to reduce the lipid deposition of ducks. The liver (L), abdominal adipose (AA), and subcutaneous adipose (SA) were the main tissues of lipid metabolism and deposition of ducks. However, the mechanisms of lipid metabolism and deposition of ducks under RF have not been fully clarified. In this study, in order to better understand the mechanisms of lipid metabolism and deposition in ducks under RF, a total of 120 male Nonghua ducks were randomly divided into a free feeding group (FF, n = 60) and RF group (RF, n = 60), then comparative transcriptomic analysis of L, AA, and SA between FF (n = 3) and RF (n = 3) ducks was performed at 56 d of age. Phenotypically, L, AA, and SA index of FF group was higher than that in RF group. There were 279, 390, and 557 differentially expressed genes (DEGs) in L, AA, and SA. Functional enrichment analysis revealed that ECM-receptor interaction and metabolic pathways were significantly enriched in L, AA, and SA. Lipid metabolism-related pathways including fatty acid metabolism, unsaturated fatty acid synthesis, and steroidogenesis were significantly enriched in AA and SA. Moreover, through integrated analysis weighted gene coexpression network (WGCNA) and protein-protein interaction network, 10 potential candidate genes involved in the ECM-receptor interaction and lipid metabolism pathways were identified, including 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), aldolase B (ALDOB), formimidoyltransferase cyclodeaminase(FTCD), phosphoenolpyruvate carboxykinase 1 (PCK1), tyrosine aminotransferase (TAT), stearoyl-CoA desaturase (SCD), squalene epoxidase (SQLE), phosphodiesterase 4B (PDE4B), choline kinase A (CHKA), and elongation of very-long-chain fatty acids-like 2 (ELOVL2), which could play a key role in lipid metabolism and deposition of ducks under RF. Our study reveals that the liver might regulate the lipid metabolism of abdominal adipose and subcutaneous adipose through ECM-receptor interaction and metabolic pathways (fatty acid metabolism, unsaturated fatty acid synthesis, and steroid synthesis), thus to reduce the lipid deposition of ducks under RF. These results provide novel insights into the avian lipid metabolism and will help better understand the underlying molecular mechanisms

A multiplex microfluidic loop-mediated isothermal amplification array for detection of malaria-related parasites and vectors

Malaria infection poses a great threaten to public health even nowadays. The conventional diagnosis tools of malaria parasites and vectors require systematic training for the observers accompanied by the low throughput. In this study, a new detection system, i.e., multiplex microfluidic loop-mediated isothermal amplification (m mu LAMP) array, was developed to provide a convenient, rapid and economical detection system for malaria diagnosis. A microfluidic-based detection chip was designed and developed, targeting the conserved gene of four Anopheles and two Plasmodium species responsible for most of the malaria cases occurred in China. The DNA preparation of Anopheles and Plasmodium samples was realized by using a newly-developed DNA extraction method. For this m mu LAMP array system, the detection limit was determined to be 1 pg of targeting DNA with high sensitivity (&gt;95%) and specificity (100%). Further, the accuracy of such m mu LAMP analysis was evaluated by the analysis of 48 Anopheles mosquito samples, of which 30 were termed to be target Anopheles, displaying high consistency with that by morphological analysis. In conclusion, the m mu LAMP detection system was proved to be a visible, sensitive, specific and high-throughput diagnostic tool. Considering the portable manipulation of such detection system, our studies shed light on its potential application of malaria surveillance on the spot.</p

Comparative Transcriptome Analysis Provided a New Insight into the Molecular Mechanisms of Epididymis Regulating Semen Volume in Drakes

Semen volume is an important factor in artificial insemination (AI) of ducks. In drakes, seminal plasma that is produced by the epididymis determines the semen volume. However, the mechanism of epididymis regulating semen volume of drakes remains unclear. Therefore, the aim of the present study was to preliminarily reveal the mechanism regulating the semen volume through comparing the epididymal histomorphology and mRNA expression profiles between drakes with high-volume semen (HVS) and low-volume semen (LVS). Phenotypically, drakes in the HVS group produced more sperm than drakes in the LVS group. In addition, compared with the HVS group, the ductal square of ductuli conjugentes (DC) and dutus epididymidis (DE) in epididymis was significantly smaller in the LVS group, and the lumenal diameter and epithelial thickness of DC/DE were significantly shorter in the LVS group. In transcriptional regulation, 72 different expression genes (DEGs) were identified from the epididymis between HVS and LVS groups. Gene Ontology (GO) analysis indicated that the DEGs were mainly related to hormone secretion, neurotransmitter synthesis/transport, transmembrane signal transduction, transmembrane transporter activity, and nervous system development (p &lt; 0.05). Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis showed that the DEGs were significantly enriched in pathways associated with hormone and neurotransmitter transmission (p &lt; 0.05). In addition, further analysis of the top five pathways enriched by KEGG, nine key candidate genes (including SLC18A2, SNAP25, CACNA1B, GABRG2, DRD3, CAMK2A, NR5A1, and STAR) were identified, which could play a crucial role in the formation of semen. These data provide new insights into the molecular mechanism regulating semen volume of drakes and make feasible the breeding of drakes by semen volume

Meta‐Analysis Global Group in Chronic Heart Failure score for the prediction of mortality in valvular heart disease

Abstract Aims Valvular heart disease (VHD) is one of the leading causes of heart failure. Clinically significant VHD can induce different patterns of cardiac remodelling, and risk stratification is challenging in patients with various degrees of cardiac dysfunction. The study aimed to investigate the prognostic implications of Meta‐Analysis Global Group in Chronic Heart Failure (MAGGIC) score in patients with VHD. Methods and results This study used data from the China Valvular Heart Disease (China‐VHD) registry, which was a multicentre, prospective, observational cohort study for patients with significant (at least moderate) VHD. In total, 10 446 patients with moderate or greater VHD from the China‐VHD study were included in the present analysis. The primary outcome of interest was all‐cause mortality within 2 years. Among 10 446 patients with VHD, the mean age was 61.98 ± 13.47 years, and 5819 (55.7%) were male. During 2 years of follow‐up, 895 (8.6%) patients died. The MAGGIC score was monotonically and independently associated with mortality in both total cohort [adjusted hazard ratio: 1.095, 95% confidence interval (CI): 1.084–1.107, P < 0.001] and most types of VHD (aortic regurgitation, mitral stenosis, mitral regurgitation, tricuspid regurgitation, mixed aortic stenosis and aortic regurgitation, and multiple VHD). The score was also an independent prognostic factor in patients with or without symptoms or preserved left ventricular ejection fraction (LVEF) and exhibited both satisfactory discrimination and calibration properties in predicting mortality. The prognostic value of MAGGIC score was robust in most quartiles of N‐terminal pro‐brain natriuretic peptide level, with no significant interaction observed (Pinteraction = 0.498). Compared with the EuroSCORE II, the MAGGIC score achieved significantly better predictive performance in overall population [C index: 0.769 vs. 0.727; net reclassification improvement index (95% CI): 0.354 (0.313–0.396), P < 0.001; integrated discrimination improvement index (95% CI): 0.069 (0.052–0.085), P < 0.001] and in subgroups of patients divided by therapeutic strategy, LVEF, symptomatic status, stage of VHD, and aetiology of VHD. Conclusions The MAGGIC score is a reliable prognostic factor across the range of cardiac dysfunction in VHD and may assist in risk stratification and guide clinical decision‐making