Partial Extinction, Permanence, and Global Attractivity in Nonautonomous n-Species Gilpin-Ayala Competitive Systems with Impulses

The qualitative properties of general nonautonomous n-species Gilpin-Ayala competitive systems with impulsive effects are studied. Some new criteria on the permanence, extinction, and global attractivity of partial species are established by using the methods of inequalities estimate and Liapunov functions

Yielding and hardening of flexible fiber packings during triaxial compression

This paper examines the mechanical response of flexible fiber packings subject to triaxial compression. Short fibers yield in a manner similar to typical granular materials in which the deviatoric stress remains nearly constant with increasing strain after reaching a peak value. Interestingly, long fibers exhibit a hardening behavior, where the stress increases rapidly with increasing strain at large strains and the packing density continuously increases. Phase diagrams for classifying the bulk mechanical response as yielding, hardening, or a transition regime are generated as a function of the fiber aspect ratio, fiber-fiber friction coefficient, and confining pressure. Large fiber aspect ratio, large fiber-fiber friction coefficient, and large confining pressure promote hardening behavior. The hardening packings can support much larger loads than the yielding packings contributing to the stability and consolidation of the granular structure, but larger internal axial forces occur within fibers.Comment: 14 pages, 4 figure

Unexpected CRISPR off-target mutation pattern in vivo are not typically germline-like [preprint]

A computationally evolutionary investigation was performed to re-analyze the WGS data of the two studies published in Nature Methods (2015, 2017) with opposite conclusions on CRISPR off-target mutations. Our analysis concluded that the so-called unexpected SNVs pattern obtained by the study of Schaefer et al. are not typically germline-like. Some of unusual and unidentified mutations may arise, but the real reasons remain to be explored. Based on the available data and a direct comparison of the two studies, we presented two possible reasons and future re-analysis directions that may contribute to such different conclusions. To characterize the authentic CRISPR-mediated mutations, we are required to have appropriate controls to rule out other sources of mutations, which will be needed for benchmarking of targeting safety of CRISPR-based gene therapy

The intrinsic disorder related alloy scattering in ZrNiSn half-Heusler thermoelectric materials

The intrinsic structural disorder dramatically affects the thermal and electronic transport in semiconductors. Although normally considered an ordered compound, the half-Heusler ZrNiSn displays many transport characteristics of a disordered alloy. Similar to the (Zr,Hf)NiSn based solid solutions, the unsubstituted ZrNiSn compound also exhibits charge transport dominated by alloy scattering, as demonstrated in this work. The unexpected charge transport, even in ZrNiSn which is normally considered fully ordered, can be explained by the Ni partially filling interstitial sites in this half-Heusler system. The influence of the disordering and defects in crystal structure on the electron transport process has also been quantitatively analyzed in ZrNiSn1-xSbx with carrier concentration n_H ranging from 5.0×10^(19) to 2.3×10^(21) cm^(−3) by changing Sb dopant content. The optimized carrier concentration n_H ≈ 3–4×10^(20) cm^(−2) results in ZT ≈ 0.8 at 875K. This work suggests that MNiSn (M = Hf, Zr, Ti) and perhaps most other half-Heusler thermoelectric materials should be considered highly disordered especially when trying to understand the electronic and phonon structure and transport features

Discrete Element Method Model of Elastic Fiber Uniaxial Compression

A flexible fiber model based on the discrete element method (DEM) is presented and validated for the simulation of uniaxial compression of flexible fibers in a cylindrical container. It is found that the contact force models in the DEM simulations have a significant impact on compressive forces exerted on the fiber bed. Only when the geometry-dependent normal contact force model and the static friction model are employed, the simulation results are in good agreement with experimental results. Systematic simulation studies show that the compressive force initially increases and eventually saturates with an increase in the fiber-fiber friction coefficient, and the fiber-fiber contact forces follow a similar trend. The compressive force and lateral shear-to-normal stress ratio increase linearly with increasing fiber-wall friction coefficient. In uniaxial compression of frictional fibers, more static friction contacts occur than dynamic friction contacts with static friction becoming more predominant as the fiber-fiber friction coefficient increases.Comment: 30 pages, 14 figures, submitted for publicatio

Electron and phonon transport in Co-doped FeV_(0.6)Nb_(0.4)Sb half-Heusler thermoelectric materials

The electron and phonon transport characteristics of n-type Fe_(1−x) Co_x V_(0.6)Nb_(0.4)Sb half-Heusler thermoelectric compounds is analyzed. The acoustic phonon scattering is dominant in the carrier transport. The deformation potential of E_(def) = 14.1 eV and the density of state effective mass m^* ≈ 2.0 m_e are derived under a single parabolic band assumption. The band gap is calculated to be ∼0.3 eV. Electron and phonon mean free paths are estimated based on the low and high temperature measurements. The electron mean free path is higher than the phonon one above room temperature, which is consistent with the experimental result that the electron mobility decreases more than the lattice thermal conductivity by grain refinement to enhance boundary scattering. A maximum ZT value of ∼0.33 is obtained at 650 K for x = 0.015, an increase by ∼60% compared with FeVSb. The optimal doping level is found to be ∼3.0 × 10^(20) cm^(−3) at 600 K

Copy-move forgery detection using combined features and transitive matching

Recently, the research of Internet of Things (IoT) and Multimedia Big Data (MBD) has been growing tremendously. Both IoT and MBD have a lot of multimedia data, which can be tampered easily. Therefore, the research of multimedia forensics is necessary. Copy-move is an important branch of multimedia forensics. In this paper, a novel copy-move forgery detection scheme using combined features and transitive matching is proposed. First, SIFT and LIOP are extracted as combined features from the input image. Second, transitive matching is used to improve the matching relationship. Third, a filtering approach using image segmentation is proposed to filter out false matches. Fourth, affine transformations are estimated between these image patches. Finally, duplicated regions are located based on those affine transformations. The experimental results demonstrate that the proposed scheme can achieve much better detection results on the public database under various attacks

A Canonical Correlation Analysis of AIDS Restriction Genes and Metabolic Pathways Identifies Purine Metabolism as a Key Cooperator

Human immunodeficiency virus causes a severe disease in humans, referred to as immune deficiency syndrome. Studies on the interaction between host genetic factors and the virus have revealed dozens of genes that impact diverse processes in the AIDS disease. To resolve more genetic factors related to AIDS, a canonical correlation analysis was used to determine the correlation between AIDS restriction and metabolic pathway gene expression. The results show that HIV-1 postentry cellular viral cofactors from AIDS restriction genes are coexpressed in human transcriptome microarray datasets. Further, the purine metabolism pathway comprises novel host factors that are coexpressed with AIDS restriction genes. Using a canonical correlation analysis for expression is a reliable approach to exploring the mechanism underlying AIDS

Restless Legs Syndrome in Chinese Patients With Sporadic Amyotrophic Lateral Sclerosis

Objective: To evaluate the frequency and clinical features of restless legs syndrome (RLS) in a group of Chinese patients with amyotrophic lateral sclerosis (ALS).Methods: 109 Patients included in this study fulfilled the revised El Escorial diagnostic criteria for clinically definite, probable and lab-supported probable ALS, and a group of 109 control subjects was matched for age and sex to the ALS group. Disease severity was assessed by the revised ALS functional rating scale (ALSFRS-R). The diagnosis of RLS was made according to the criteria of the International RLS Study Group. Other characteristics including sleep quality, excessive daytime sleepiness (EDS), REM sleep behavior disorder (RBD), depression and anxiety were also evaluated in ALS patients.Results: RLS was significantly more frequent in ALS patients than in control subjects (14.6 vs. 0.9%; P < 0.05). Compared to those without RLS, ALS patients with RLS reported a higher frequency of anxiety and EDS. ALS patients with RLS showed more severe legs dysfunction. EDS and legs function scores of the ALSFRS-R were independent factors significantly associated with RLS in ALS patients.Conclusions: Our findings suggest that Chinese ALS patients exhibit a high frequency of RLS symptoms and that these patients may benefit from recognition of the condition and optimized management of its symptoms. Moreover, ALS patients might cause circadian rhythms disturbance and our study further supports that ALS is a heterogeneous disorder involving multiple systems; further studies are needed to confirm these preliminary findings

Porous Bilayer Electrode‐Guided Gas Diffusion for Enhanced CO 2 Electrochemical Reduction

Comparing with the massive efforts in developing innovative catalyst materials system and technologies, structural design of cells has attracted less attention on the road toward high‐performance electrochemical CO2 reduction reaction (eCO2RR). Herein, a hybrid gas diffusion electrode‐based reaction cell is proposed using highly porous carbon paper (CP) and graphene aerogels (GAs), which is expected to offer directional diffusion of gas molecules onto the catalyst bed, to sustain a high performance in CO2 conversion. The above‐mentioned hypothesis is supported by the experimental and simulation results, which show that the CP + GA combined configuration increases the Faraday efficiency (FE) from ≈60% to over 94% toward carbon monoxide (CO) and formate production compared with a CP only cell with Cu2O as the catalyst. It also suppresses the undesirable side reaction–hydrogen evolution over 65 times than the conventional H‐type cell (H‐cell). By combining with advanced catalysts with high selectivity, a 100% FE of the cell with a high current density can be realized. The described strategy sheds an extra light on future development of eCO2RR with a structural design of cell‐enabled high CO2 conversion