882 research outputs found
Effects of airflow on hydrodynamic modulation of short surface waves by long waves
A model is developed for the effects of
airflow on hydrodynamic modulation of short surface gravity waves by a dominant long
wave. The propagation of the short wave and distribution of its wavenumber and energy
density with respect to phase of the long wave are specified by the kinematic
conservation equation and the wind-forcing modified wave action equation, which are
solved using linear ray theory and modelled by the Reynolds-averaged Navier-Stokes
equations
FMRI Clustering and False Positive Rates
Recently, Eklund et al. (2016) analyzed clustering methods in standard FMRI
packages: AFNI (which we maintain), FSL, and SPM [1]. They claimed: 1) false
positive rates (FPRs) in traditional approaches are greatly inflated,
questioning the validity of "countless published fMRI studies"; 2)
nonparametric methods produce valid, but slightly conservative, FPRs; 3) a
common flawed assumption is that the spatial autocorrelation function (ACF) of
FMRI noise is Gaussian-shaped; and 4) a 15-year-old bug in AFNI's 3dClustSim
significantly contributed to producing "particularly high" FPRs compared to
other software. We repeated simulations from [1] (Beijing-Zang data [2], see
[3]), and comment on each point briefly.Comment: 3 pages, 1 figure. A Letter accepted in PNA
Antiperovskite Li3OCl Superionic Conductor Films for Solid-State Li-Ion Batteries.
Antiperovskite Li3OCl superionic conductor films are prepared via pulsed laser deposition using a composite target. A significantly enhanced ionic conductivity of 2.0 × 10-4 S cm-1 at room temperature is achieved, and this value is more than two orders of magnitude higher than that of its bulk counterpart. The applicability of Li3OCl as a solid electrolyte for Li-ion batteries is demonstrated
Computing the minimum distance between two Bézier curves
International audienceA sweeping sphere clipping method is presented for computing the minimum distance between two Bézier curves. The sweeping sphere is constructed by rolling a sphere with its center point along a curve. The initial radius of the sweeping sphere can be set as the minimum distance between an end point and the other curve. The nearest point on a curve must be contained in the sweeping sphere along the other curve, and all of the parts outside the sweeping sphere can be eliminated. A simple sufficient condition when the nearest point is one of the two end points of a curve is provided, which turns the curve/curve case into a point/curve case and leads to higher efficiency. Examples are shown to illustrate efficiency and robustness of the new method
Computing the minimum distance between a point and a clamped B-spline surface
International audienceThe computation of the minimum distance between a point and a surface is important for the applications such as CAD/CAM, NC verification, robotics and computer graphics. This paper presents a spherical clipping method to compute the minimum distance between a point and a clamped B-spline surface. The surface patches outside the clipping sphere which do not contain the nearest point are eliminated. Another exclusion criterion whether the nearest point is on the boundary curves of the surface is employed, which is proved to be superior to previous comparable criteria. Examples are also shown to illustrate efficiency and correctness of the new method
Computing the minimum distance between a point and a NURBS curve
International audienceA new method is presented for computing the minimum distance between a point and a NURBS curve. It utilizes a circular clipping technique to eliminate the curve parts outside a circle with the test point as its center point. The radius of the elimination circle becomes smaller and smaller during the subdivision process. A simple condition for terminating the subdivision process is provided, which leads to very few subdivision steps in the new method. Examples are shown to illustrate the efficiency and robustness of the new method
Phenyl 3-methoxy-4-phenoxybenzoate
In the title molecule, C20H16O4, the two outermost phenyl rings form dihedral angles of 79.80 (7) and 69.35 (7)° with the central benzene ring. In the crystal structure, weak intermolecular C—H⋯O interactions link the molecules into ribbons propagating along [10]
LayoutDETR: Detection Transformer Is a Good Multimodal Layout Designer
Graphic layout designs play an essential role in visual communication. Yet
handcrafting layout designs is skill-demanding, time-consuming, and
non-scalable to batch production. Generative models emerge to make design
automation scalable but it remains non-trivial to produce designs that comply
with designers' multimodal desires, i.e., constrained by background images and
driven by foreground content. We propose LayoutDETR that inherits the high
quality and realism from generative modeling, while reformulating content-aware
requirements as a detection problem: we learn to detect in a background image
the reasonable locations, scales, and spatial relations for multimodal
foreground elements in a layout. Our solution sets a new state-of-the-art
performance for layout generation on public benchmarks and on our newly-curated
ad banner dataset. We integrate our solution into a graphical system that
facilitates user studies, and show that users prefer our designs over baselines
by significant margins. Our code, models, dataset, graphical system, and demos
are available at https://github.com/salesforce/LayoutDETR
Protubérances sur la courbe neutre sous l'effet de la périodicité des contraintes
En 2007, Wadih & al. montraient l’aspect
intrigant de l’apparition de doigts ou protubérances sur la courbe neutre lors de
l’étude de la stabilité d’un écoulement purement oscillatoire, phénomène observé de
manière moindre par Blennerhassett & al(2006). Nous confirmons que ce phénomène
provenant de la coalescence de deux ondes progressives et de directions opposées se
produit aussi bien dans les instabilités de type Kelvin-Helmoltz que dans les
instabilités de type Rayleigh-Bénard avec g-jitter
Radiation-induced Assembly of Rad51 and Rad52 Recombination Complex Requires ATM and c-Abl
Cells from individuals with the recessive cancer-prone disorder ataxia telangiectasia (A-T) are hypersensitive to ionizing radiation (I-R). ATM (mutated in A-T) is a protein kinase whose activity is stimulated by I-R. c-Abl, a nonreceptor tyrosine kinase, interacts with ATM and is activated by ATM following I-R. Rad51 is a homologue of bacterial RecA protein required for DNA recombination and repair. Here we demonstrate that there is an I-R-induced Rad51 tyrosine phosphorylation, and this induction is dependent on both ATM and c-Abl. ATM, c-Abl, and Rad51 can be co-immunoprecipitated from cell extracts. Consistent with the physical interaction, c-Abl phosphorylates Rad51 in vitro and in vivo. In assays using purified components, phosphorylation of Rad51 by c-Abl enhances complex formation between Rad51 and Rad52, which cooperates with Rad51 in recombination and repair. After I-R, an increase in association between Rad51 and Rad52 occurs in wild-type cells but not in cells with mutations that compromise ATM or c-Abl. Our data suggest signaling mediated through ATM, and c-Abl is required for the correct post-translational modification of Rad51, which is critical for the assembly of Rad51 repair protein complex following I-R
- …