Bifurcation Analysis and Chaos Control in a Discrete Epidemic System

The dynamics of discrete SI epidemic model, which has been obtained by the forward Euler scheme, is investigated in detail. By using the center manifold theorem and bifurcation theorem in the interior R+2, the specific conditions for the existence of flip bifurcation and Neimark-Sacker bifurcation have been derived. Numerical simulation not only presents our theoretical analysis but also exhibits rich and complex dynamical behavior existing in the case of the windows of period-1, period-3, period-5, period-6, period-7, period-9, period-11, period-15, period-19, period-23, period-34, period-42, and period-53 orbits. Meanwhile, there appears the cascade of period-doubling 2, 4, 8 bifurcation and chaos sets from the fixed point. These results show the discrete model has more richer dynamics compared with the continuous model. The computations of the largest Lyapunov exponents more than 0 confirm the chaotic behaviors of the system x→x+δ[rN(1-N/K)-βxy/N-(μ+m)x], y→y+δ[βxy/N-(μ+d)y]. Specifically, the chaotic orbits at an unstable fixed point are stabilized by using the feedback control method

Effects of fat deposition on the expression of insulin-signaling pathway and mTORC1 genes in Finnhorse mares

Obesity and insulin resistance (IR) are key factors lead to equine metabolic syndrome and laminitis. Diet may play an important role in eliciting obesity by affecting insulin dynamics. Insulin-pathway signaling and mTORC1 genes may contribute to incred IR. The first objective of this study was to find and validate internal control genes for quantitative PCR method for adipose tissues in Finnhorse mares. The second aim was to quantitate the expression of mTORC1 and insulin-pathway associated genes after pasture season in two different treatment groups of Finnhorse mares and compare gene expression differences between treatment groups. In addition, gene expression differences were compared between two different adipose tissues. Twenty-two mares were equally divided into eleven equal pairs, the two mares of each group were randomly grazed either on cultivated high-yielding pasture (CG) or on semi-natural grassland (NG) from the end of May to the beginning of September. Eight pairs of Finnhorse mares were selected for gene expression profiling. Subcutaneous adipose tissue (SAT) samples were collected from two groups of Finnhorse mares after pasture season. Gene expression of neck and tailhead SAT were determined with quantitative Real-Time PCR method (qPCR). The selected internal control genes were actin beta (ACTB), glucuronidase beta (GUSB) and mitochondrial ribosomal protein L39 (MRPL39). Candidate genes were mechanistic target of rapamycin (MTOR), sterol regulatory element binding transcription factor 1 (SREBF1), sterol regulatory element binding transcription factor 2 (SREBF2), TBC1 domain family member 7 (TBC1D7), leptin (LEP), glucose transporter type 4 (GLUT4), monocyte chemoattractant protein-1 (MCP-1), retinol binding protein 4 (RBP4), tuberous sclerosis 1 (TSC1), tuberous sclerosis 2 (TSC2). There were no distinct gene expression differences between NG and CG groups in both neck and tailhead SAT. However, RBP4 had significantly (P=0.035) higher and GLUT4 had a trend (P=0.064) to higher mRNA expression in CG group in neck SAT. TSC1 had a trend (P=0.071) of higher expression in CG group in tailhead SAT. Gene expression differences were observed between tailhead and neck SAT. SREBF1 and GLUT4 had significantly (P=0.007 and P=0.026, respectively) higher expression levels in tailhead SAT compared to neck SAT. RBP4 had a trend (P=0.066) to higher expression in neck SAT compared to tailhead SAT. Minor differences in gene expression between NG and CG groups indicate that pasture-associated fat depositionmaynotconsiderably affect expressionof insulin-pathway and mTORC1 genes associated to obesity and IR in studied subcutaneous adipose tissues. These results also provide additional evidence to our hypothesis that fattening resulting on unrestricted grazing on cultivated high-yielding pasture does not increase the risk of metabolic diseases in Finnhorse mares when they have normal body condition at the beginning of the grazing season

Productive Aging Conference Report

Productive Aging Conference Repor

Seismic Azimuthal Anisotropy Beneath a Fast Moving Ancient Continent: Constraints from Shear Wave Splitting Analysis in Australia

Seismic Azimuthal Anisotropy Beneath Australia is Investigated using Splitting of the Teleseismic PKS, SKKS, and SKS Phases to Delineate Asthenospheric Flow and Lithospheric Deformation Beneath One of the Oldest and Fast-Moving Continents on Earth. in Total 511 Pairs of High-Quality Splitting Parameters Were Observed at 116 Seismic Stations. Unlike Other Stable Continental Areas in Africa, East Asia, and North America, Where Spatially Consistent Splitting Parameters Dominate, the Fast Orientations and Splitting Times Observed in Australia Show a Complex Pattern, with a Slightly Smaller Than Normal Average Splitting Time of 0.85 ± 0.33 S. on the North Australian Craton, the Fast Orientations Are Mostly N-S, which is Parallel to the Absolute Plate Motion (APM) Direction in the Hotspot Frame. Those Observed in the South Australian Craton Are Mostly NE-SW and E-W, Which Are Perpendicular to the Maximum Lithospheric Horizontal Shortening Direction. in East Australia, the Observed Azimuthal Anisotropy Can Be Attributed to Either APM Induced Simple Shear or Lithospheric Fabric Parallel to the Strike of the Orogenic Belts. the Observed Spatial Variations of the Seismic Azimuthal Anisotropy, When Combined with Results from Depth Estimation Utilizing the Spatial Coherency of the Splitting Parameters and Seismic Tomography Studies, suggest that the Azimuthal Anisotropy in Australia Can Mostly Be Related to Simple Shear in the Rheologically Transition Layer between the Lithosphere and Asthenosphere. Non-APM Parallel Anisotropy is Attributable to Modulations of the Mantle Flow System by Undulations of the Bottom of the Lithosphere, with a Spatially Variable Degree of Contribution from Lithospheric Fabric

An Event-Based Neurobiological Recognition System with Orientation Detector for Objects in Multiple Orientations

A new multiple orientation event-based neurobiological recognition system is proposed by integrating recognition and tracking function in this paper, which is used for asynchronous address-event representation (AER) image sensors. The characteristic of this system has been enriched to recognize the objects in multiple orientations with only training samples moving in a single orientation. The system extracts multi-scale and multi-orientation line features inspired by models of the primate visual cortex. An orientation detector based on modified Gaussian blob tracking algorithm is introduced for object tracking and orientation detection. The orientation detector and feature extraction block work in simultaneous mode, without any increase in categorization time. An addresses lookup table (addresses LUT) is also presented to adjust the feature maps by addresses mapping and reordering, and they are categorized in the trained spiking neural network. This recognition system is evaluated with the MNIST dataset which have played important roles in the development of computer vision, and the accuracy is increase owing to the use of both ON and OFF events. AER data acquired by a DVS are also tested on the system, such as moving digits, pokers, and vehicles. The experimental results show that the proposed system can realize event-based multi-orientation recognition.The work presented in this paper makes a number of contributions to the event-based vision processing system for multi-orientation object recognition. It develops a new tracking-recognition architecture to feedforward categorization system and an address reorder approach to classify multi-orientation objects using event-based data. It provides a new way to recognize multiple orientation objects with only samples in single orientation

Arabidopsis Putative Deacetylase AtSRT2 Regulates Basal Defense by Suppressing PAD4, EDS5 and SID2 Expression

The silent information regulator protein (Sir2) and its homologs are NAD+-dependent deacetylase enzymes that play important roles in a variety of physiological processes. However, the functions of the Sir2 family in plants are poorly understood. Here, we report that Arabidopsis AtSRT2, a homolog of yeast Sir2, negatively regulates plant basal defense against the pathogen Pseudomonas syringae pv. tomato DC3000 (PstDC3000). In response to PstDC3000 infection, the expression of AtSRT2 was down-regulated in a salicylic acid (SA)-independent manner. In addition, knock-out of AtSRT2 (srt2) enhanced resistance against PstDC3000 and increased expression of pathogenesis-related gene 1 (PR1). Conversely, overexpression of AtSRT2 resulted in hypersusceptibility to PstDC3000 and impaired PR1 induction. Consistent with this phenotype, expression of PAD4, EDS5 and SID2, three essential genes in the SA biosynthesis pathway, were increased in the srt2 mutant and decreased in AtSRT2-overexpressing plants. Taken together, these results demonstrate that AtSRT2 is a negative regulator of basal defense, possibly by suppressing SA biosynthesis