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Buffeting-induced accelerations and displacements of bridge deck girders commonly drive the bridge design’s comfort, operational, and strength limit states. The scattered nature of the main wind characteristics and bridge responses recorded in multiple monitoring campaigns make deterministic approaches insufficient to assess the bridge’s performance along its life span. This study reports comprehensive sensitivity and reliability studies conducted to unveil the influence of multiple parameters controlling long-span bridges’ buffeting responses. The impact of several sets of random variables on the reliability of the Great Belt Bridge is systematically studied. A detailed treatment of the uncertainty of flutter derivatives consisting of combining their frequency-dependent random definition with their experimentally defined correlation is proposed. Results show the drastic impact of uncertainty in the flutter derivatives, the vertical turbulence intensity, the mean wind velocity, and the definition of the buffeting loads, particularly the slopes of the force coefficients and the aerodynamic admittance, on the buffeting-induced accelerations. The influence of aerodynamic admittance on the results is analyzed in the context of random definitions of mean velocity, turbulent intensities, length scales, structural damping, and aerodynamic characteristics. The computational efficiency of gradient-based reliability methods is discussed, showing its potential to address high-dimensional problems within design frameworks. 

Abstract BackgroundTransgenic plants are essential for both basic and applied plant biology. Recently, fluorescent and colorimetric markers were developed to enable nondestructive identification of transformed seeds and accelerate the generation of transgenic plant lines. Yet, transformation often results in the integration of multiple copies of transgenes in the plant genome. Multiple transgene copies can lead to transgene silencing and complicate the analysis of transgenic plants by requiring researcher to track multiple T-DNA loci in future generations. Thus, to simplify analysis of transgenic lines, plant researchers typically screen transformed plants for lines where the T-DNA inserted in a single locus — an analysis that involves laborious manual counting of fluorescent and non-fluorescent seeds for screenable markers. ResultsTo expedite T-DNA segregation analysis, we developed SeedSeg, an image analysis tool that uses a segmentation algorithm to count the number of transformed and wild-type seeds in an image. SeedSeg runs a chi-squared test to determine the number of T-DNA loci. Parameters can be adjusted to optimize for different brightness intensities and seed sizes. ConclusionsBy automating the seed counting process, SeedSeg reduces the manual labor associated with identifying transgenic lines containing a single T-DNA locus. SeedSeg is adaptable to different seed sizes and visual transgene markers, making it a versatile tool for accelerating plant research. 

This study reports the nonlinear aerostatic stability studies carried out for a suspension footbridge with a curved deck spanning 275 meters over the Miño River between Spain and Portugal. The footbridge's aerostatic performance is controlled by its highly aesthetic but complex three-dimensional configuration, the high slenderness of the deck, the construction process, and the aerodynamic characteristics of the triangular 4.5-meter-wide bluff deck cross- section, which demands a detailed aerodynamic study. The analysis is conducted using a nonlinear modal-based method recently developed by the authors. The deck's rotation is driven not only by the aerodynamic moment-induced rotation but also by the drag-induced rotation due to the configuration of the cable supporting system and, very significantly, by the lift- induced rotation due to the deck's curvature.