6,429 research outputs found
(E)-N′-(2-Chlorobenzylidene)-4-methoxybenzohydrazide
The molecule of the title compound, C15H13ClN2O2, adopts an E geometry about the C=N bond. The dihedral angle between the two benzene rings is 62.7 (2)°. In the crystal structure, molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming chains running along the c axis
Preflare very long-periodic pulsations observed in Halpha emission before the onset of a solar flare
Very long-periodic pulsations during preflare phases (preflare-VLPs) have
been detected in the full-disk solar soft X-Ray (SXR) flux (see Tan et al.
2016). They may be regarded as precursors to solar flares and may help us
better understand the trigger mechanism of solar flares. In this letter, we
report a preflare-VLP event before the onset of an M1.1 circular-ribbon flare
on 2015 October 16. It was simultaneously observed in Halpha, SXR, and extreme
ultraviolet (EUV) wavelengths, which were recorded by the NVST, GOES, EVE, and
AIA respectively. The preflare-VLP is identified as the repeat and
quasi-periodic pulses in light curves during preflare phase, which might be
modulated by LRC-circuit oscillation in the current-carrying plasma loop. The
quasi-periodicity can be determined from the Fourier power spectrum with Markov
chain Monte Carlo (MCMC)-based Bayesian (e.g., Liang et al. 2020), such as ~9.3
minutes. We present the first report of a preflare-VLP event in the local
Halpha line and EUV wavelength, which could be considered a precursor of a
solar flare. This finding should therefore prove useful for the prediction of
solar flares, especially for powerful flares.Comment: 4 pages, 4 figures, accepted by A&A Letters. The abstract was
rewritte
Distributional Modeling for Location-Aware Adversarial Patches
Adversarial patch is one of the important forms of performing adversarial
attacks in the physical world. To improve the naturalness and aggressiveness of
existing adversarial patches, location-aware patches are proposed, where the
patch's location on the target object is integrated into the optimization
process to perform attacks. Although it is effective, efficiently finding the
optimal location for placing the patches is challenging, especially under the
black-box attack settings. In this paper, we propose the Distribution-Optimized
Adversarial Patch (DOPatch), a novel method that optimizes a multimodal
distribution of adversarial locations instead of individual ones. DOPatch has
several benefits: Firstly, we find that the locations' distributions across
different models are pretty similar, and thus we can achieve efficient
query-based attacks to unseen models using a distributional prior optimized on
a surrogate model. Secondly, DOPatch can generate diverse adversarial samples
by characterizing the distribution of adversarial locations. Thus we can
improve the model's robustness to location-aware patches via carefully designed
Distributional-Modeling Adversarial Training (DOP-DMAT). We evaluate DOPatch on
various face recognition and image recognition tasks and demonstrate its
superiority and efficiency over existing methods. We also conduct extensive
ablation studies and analyses to validate the effectiveness of our method and
provide insights into the distribution of adversarial locations
Reduced glutamine synthetase activity alters the fecundity of female Bactrocera dorsalis (Hendel)
Glutamine synthetase (GS) is a key enzyme in glutamine synthesis and is associated with multiple physiological processes in insects, such as embryonic development, heat shock response, and fecundity regulation. However, little is known about the influence of GS on female fecundity in the oriental fruit fly, Bactrocera dorsalis. Based on the cloning of BdGSs, mitochondrial BdGSm and cytoplasmic BdGSc, we determined their expressions in the tissues of adult B. dorsalis. BdGSm was highly expressed in the fat body, while BdGSc was highly expressed in the head and midgut. Gene silencing by RNA interference against two BdGSs isoforms suppressed target gene expression at the transcriptional level, leading to a reduced ovarian size and lower egg production. The specific inhibitor L-methionine S-sulfoximine suppressed enzyme activity, but only the gene expression of BdGSm was suppressed. A similar phenotype of delayed ovarian development occurred in the inhibitor bioassay. Significantly lower expression of vitellogenin and vitellogenin receptor was observed when GS enzyme activity was suppressed. These data illustrate the effects of two GS genes on adult fecundity by regulating vitellogenin synthesis in different ways
Tie-dye technique and pattern features
Relationship between tie-dye technique and image pattern has been studied. Based on digital image processing, average value of HSV (hue, saturation, value) tri-component of valid tie-dye area, proportion of incompletely dyed area in HSV color space and the Tamura first three texture features of digital tie-dye image have been extracted. Then, the repeated tests and analysis of variance (ANOVA) of rotation speed and concentration have been done. The results show the obvious impact of concentration and rotation speed on the color and texture feature of tie-dye pattern. Furthermore, back propagation neutral network is developed and partial pattern features with low correlation is used to forecast the tie-dye concentration and rotation speed. The experiment results show the 100% rate of forecast, which proves that pattern features can effectively achieve the technique forecast
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