Event History Analysis of Dynamic Communication Networks

Statistical analysis on networks has received growing attention due to demand from various emerging applications. In dynamic networks, one of the key interests is to model the event history of time-stamped interactions amongst nodes. We propose to model dynamic directed communication networks via multivariate counting processes. A pseudo partial likelihood approach is exploited to capture the network dependence structure. Asymptotic results of the resulting estimation are established. Numerical results are performed to demonstrate effectiveness of our proposal

Experimental Study and ANN Dual-Time Scale Perturbation Model of Electrokinetic Properties of Microbiota

[Abstract] The electrokinetic properties of the rumen microbiota are involved in cell surface adhesion and microbial metabolism. An in vitro study was carried out in batch culture to determine the effects of three levels of special surface area (SSA) of biomaterials and four levels of surface tension (ST) of culture medium on electrokinetic properties (Zeta potential, ξ; electrokinetic mobility, μe), fermentation parameters (volatile fatty acids, VFAs), and ST over fermentation processes (ST-a, γ). The obtained results were combined with previously published data (digestibility, D; pH; concentration of ammonia nitrogen, c(NH3-N)) to establish a predictive artificial neural network (ANN) model. Concepts of dual-time series analysis, perturbation theory (PT), and Box-Jenkins Operators were applied for the first time to develop an ANN model to predict the variations of the electrokinetic properties of microbiota. The best dual-time series Radial Basis Functions (RBR) model for ξ of rumen microbiota predicted ξ for >30,000 cases with a correlation coefficient >0.8. This model provided insight into the correlations between electrokinetic property (zeta potential) of rumen microbiota and the perturbations of physical factors (specific surface area and surface tension) of media, digestibility of substrate, and their metabolites (NH3-N, VFAs) in relation to environmental factors.National Natural Science Foundation of China; 31172234National Natural Science Foundation of China; 31260556),Planned Science and Technology Project of Hu-nan Province; 2015NK3041Technology Specialty Fund for Cooperation between Jilin Province and the Chinese Academy of Sciences; 2016SYHZ0022Hunan Provincial Creation Development Project; 2013TF3006Xunta de Galicia; GRC2014/049Xunta de Galicia; R2014/039Ministerio de Economía, Industria y Competitividad; FJCI-2015-2607

Atomic Mechanism and Criterion for Hydrogen-Induced Transgranular to Intergranular Fracture Transition

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Experimental study and random forest prediction model of microbiome cell surface hydrophobicity

[Abstract] The cell surface hydrophobicity (CSH) is an assessable physicochemical property used to evaluate the microbial adhesion to the surface of biomaterials, which is an essential step in the microbial biofilm formation and pathogenesis. For the present in vitro fermentation experiment, the CSH of ruminal mixed microbes was considered, along with other data records of pH, ammonia-nitrogen concentration, and neutral detergent fibre digestibility, conditions of surface tension and specific surface area in two different time scales. A dataset of 170,707 perturbations of input variables, grouped into two blocks of data, was constructed. Next, Expected Measurement Moving Average – Machine Learning (EMMA-ML) models were developed in order to predict CSH after perturbations of all input variables. EMMA-ML is a Perturbation Theory method that combines the ideas of Expected Measurement, Box-Jenkins Operators/Moving Average, and Time Series Analysis. Seven regression methods have been tested: Multiple Linear regression, Generalized Linear Model with Stepwise Feature Selection, Partial Least Squares regression, Lasso regression, Elastic Net regression, Neural Networks regression, and Random Forests (RF). The best regression performance has been obtained with RF (EMMA-RF model) with an R-squared of 0.992. The model analysis has shown that CSH values were highly dependent on the in vitro fermentation parameters of detergent fibre digestibility, ammonia – nitrogen concentration, and the expected values of cell surface hydrophobicity in the first time scale.Ministerio de Economía y Competitividad; FJCI-2015- 26071Ministerio de Economía y Competitividad; UNLC08-1E-002Ministerio de Economía y Competitividad; UNLC13-13-3503Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; GRC2014/049National Natural Science Foundation of China; Grant No. 31172234National Natural Science Foundation of China; Grant No. 31260556Chinese Academy of Science; Grant No. XDA0502070

Application of indirect immunofluorescence on the diagnosis of pemphigus

Pemphigus is an autoimmune bullous disease, and although several diagnostic methods are now in use indirect immunofluorescence (IIF) is still considered an important tool for diagnosing pemphigus because of its convenience, repeatability, and reduced pain for patients. The goal of the present study was to evaluate the diagnostic value of IIF on normal human skin (NS), monkey esophagus (ME), and salt-split skin (SS) for better diagnosis of pemphigus. Clinical data of 70 patients with pemphigus and 56 control were collected. IIF on NS, ME, and SS were assessed separately by observing fluorescein deposition and comparing its differentiation to different kinds of pemphigus and its sensitivities and specificities to different substrates. Intercellular deposition of IgG was visible when IIF on NS, ME, and SS were positive in patients with pemphigus. Their corresponding sensitivities and specificities were 30.0%, 84.3%, and 70.0% and 96.4%, 96.4%, and 94.6%, respectively. The differences in sensitivity were statistically significant between NS and ME and between NS and SS (P&lt;0.001) and the specificities among the three substrates were not statistically significantly different (P&gt;0.05). As for different types of pemphigus, the sensitivities between NS and ME and between NS and SS were statistically significantly different in both Dsg1- and Dsg3-positive and only Dsg1-positive patients with pemphigus (P&lt;0.01); the sensitivities between NS and ME were statistically significantly different only in Dsg3-positive patients with pemphigus (P&lt;0.001); there were no statistically significant differences between ME and SS. We therefore propose that ME is a good substrate for pemphigus diagnosis with higher sensitivity and superior to NS, particularly for patients with anti-Dsg3 antibodies. SS is a good alternative substrate to ME with almost identical higher sensitivities and specificities for diagnosis of pemphigus.</p

A new approach to generalized chaos synchronization based on the stability of the error system

summary:With a chaotic system being divided into linear and nonlinear parts, a new approach is presented to realize generalized chaos synchronization by using feedback control and parameter commutation. Based on a linear transformation, the problem of generalized synchronization (GS) is transformed into the stability problem of the synchronous error system, and an existence condition for GS is derived. Furthermore, the performance of GS can be improved according to the configuration of the GS velocity. Further generalization and appropriation can be acquired without a stability requirement for the chaotic system’s linear part. The Lorenz system and a hyperchaotic system are taken for illustration and verification and the results of the simulation indicate that the method is effective

An extended Rice model for intergranular fracture

The plastic events occurring during the process of intergranular fracture in metals is still not well understood due to the complexity of grain boundary (GB) structures and their interactions with crack-tip dislocation plasticity. By considering the local GB structural transformation after dislocation emission from a GB in the Peierls-type Rice-Beltz model, herein we established a semi-analytical transition-state-theory-based framework to predict the most probable Mode-I stress intensity factor (SIF) for dislocation emission from a cracked GB. Using large-scale molecular dynamics (MD) simulations, we studied the fracture behaviors of bi-crystalline Fe samples with 12 different symmetric tilt GBs inside. The MD results demonstrate that the presence of GB could significantly change the SIF required for the activation of plastic events, confirming the theoretical predictions that attributes this to the energy change caused by the transformation of GB structure. Both the atomistic simulation and the theoretical model consistently indicate that, the critical dynamic SIF ( ) at which the dynamic SIF KI(t) deviates from the linearity with respect to the strain ε, increases with the increasing loading rate. However, the classical Rice model underestimates the due to its failure to consider the effects of localized fields. The present theoretical model provides a mechanism-based framework for the application of grain boundary engineering in the design and fabrication of nano-grained metals.An extended Rice model for intergranular fractureacceptedVersio

Exploring Regulation Genes Involved in the Expression of L-Amino Acid Oxidase in Pseudoalteromonas sp. Rf-1

Bacterial L-amino acid oxidase (LAAO) is believed to play important biological and ecological roles in marine niches, thus attracting increasing attention to understand the regulation mechanisms underlying its production. In this study, we investigated genes involved in LAAO production in marine bacterium Pseudoalteromonas sp. Rf-1 using transposon mutagenesis. Of more than 4,000 mutants screened, 15 mutants showed significant changes in LAAO activity. Desired transposon insertion was confirmed in 12 mutants, in which disrupted genes and corresponding functionswere identified. Analysis of LAAO activity and lao gene expression revealed that GntR family transcriptional regulator, methylase, non-ribosomal peptide synthetase, TonB-dependent heme-receptor family, Na⁺/H⁺ antiporter and related arsenite permease, N-acetyltransferase GCN5, Ketol-acid reductoisomerase and SAM-dependent methytransferase, and their coding genes may be involved in either upregulation or downregulation pathway at transcriptional, posttranscriptional, translational and/or posttranslational level. The nhaD and sdmT genes were separately complemented into the corresponding mutants with abolished LAAO-activity. The complementation of either gene can restore LAAO activity and lao gene expression, demonstrating their regulatory role in LAAO biosynthesis. This study provides, for the first time, insights into the molecular mechanisms regulating LAAO production in Pseudoalteromonas sp. Rf-1, which is important to better understand biological and ecological roles of LAAO