Boundary stabilization of quasilinear hyperbolic systems of balance laws: Exponential decay for small source terms

We investigate the long-time behavior of solutions of quasilinear hyperbolic systems with transparent boundary conditions when small source terms are incorporated in the system. Even if the finite-time stability of the system is not preserved, it is shown here that an exponential convergence towards the steady state still holds with a decay rate which is proportional to the logarithm of the amplitude of the source term. The result is stated for a system with dynamical boundary conditions in order to deal with initial data that are free of any compatibility condition

Three distinct mechanisms of long-distance modulation of gene expression in yeast

<div><p>Recent Hi-C measurements have revealed numerous intra- and inter-chromosomal interactions in various eukaryotic cells. To what extent these interactions regulate gene expression is not clear. This question is particularly intriguing in budding yeast because it has extensive long-distance chromosomal interactions but few cases of gene regulation over-a-distance. Here, we developed a medium-throughput assay to screen for functional long-distance interactions that affect the average expression level of a reporter gene as well as its cell-to-cell variability (noise). We ectopically inserted an insulated <i>MET3</i> promoter (<i>MET3pr</i>) flanked by ~1kb invariable sequences into thousands of genomic loci, allowing it to make contacts with different parts of the genome, and assayed the <i>MET3pr</i> activity in single cells. Changes of <i>MET3pr</i> activity in this case necessarily involve mechanisms that function over a distance. <i>MET3pr</i> has similar activities at most locations. However, at some locations, they deviate from the norm and exhibit three distinct patterns including low expression / high noise, low expression / low noise, and high expression / low noise. We provided evidence that these three patterns of <i>MET3pr</i> expression are caused by Sir2-mediated silencing, transcriptional interference, and 3D clustering. The clustering also occurs in the native genome and enhances the transcription of endogenous Met4-targeted genes. Overall, our results demonstrate that a small fraction of long-distance chromosomal interactions can affect gene expression in yeast.</p></div

Long-distance interaction and gene regulation of the native profile 4 sites.

<p><b>A)</b> A list of the 3C pairs between the native profile 4 sites. <b>B)</b> 3C assay between the gene pairs in A. The pairs with positive signals are labeled red in A. <b>C)</b> 3C assay between <i>MET13</i> and the rest of the profile 4 sites after translocation to Chr15. No interaction was detected at this new location. <b>D)</b> <i>MET13</i> expression measured by RT-PCR at the endogenous (End) or ectopic (Ect) location. The <i>MET13</i> mRNA level is significantly reduced on Chr15 (p-value < 0.001). The expression of the control (mCherry driven by <i>MET13pr</i> at <i>CDC20</i> locus) is unchanged.</p

Comparative Analysis of Risky Behaviors of Electric Bicycles at Signalized Intersections

<div><p><b>Objective:</b> The primary objective of this study was to compare the risky behaviors of e-bike, e-scooter, and bicycle riders as they were crossing signalized intersections.</p><p><b>Methods:</b> Pearson's chi-square test was used to identify whether there were significant differences in the risky behaviors among e-bike, e-scooter, and bicycle riders. Binary logit models were developed to evaluate how various variables affected the behaviors of 2-wheeled vehicle riders at signalized intersections. Field data collection was conducted at 13 signalized intersections in 2 cities (Nanjing and Kunming) in China.</p><p><b>Results:</b> Three different types of risky behaviors were identified, including stop beyond the stop line, riding in motorized lanes, and riding against traffic. Two-wheeled vehicle riders’ gender and age and traffic conditions were significantly associated with the behaviors of 2-wheeled vehicle riders at the selected signalized intersections.</p><p><b>Conclusions:</b> Compared to e-bike and bicycle riders, e-scooter riders are more likely to take risky behaviors. More specifically, they are more likely to ride in motorized lanes and ride against traffic.</p></div