848 research outputs found
Method based on fast fourier transform for calculating conical refraction of beams with noncircular symmetry
Conical refraction of optical beams with circular symmetry is often analyzed using Belsky-Khapalyuk-Berry (BKB) theory; however, for beams with noncircular symmetry, it is difficult to obtain analytical expressions for far-field diffraction patterns. We propose a method, based on fast Fourier transform (FFT), for calculating conical refraction of beams with noncircular symmetry and verify it experimentally using a quasi-plane wave passing through a square aperture and focusing lens. Excellent agreement between theoretical and experimental results has been achieved
Functional Characterization and Conditional Regulation of the Type VI Secretion System in Vibrio fluvialis
Antiplane Problem of Periodically Stacked Parallel Cracks in an Infinite Orthotropic Plate
The antiplane problem of the periodic parallel cracks in an infinite linear elastic orthotropic composite plate is studied in this paper. The antiplane problem is turned into the boundary value problem of partial differential equation. By constructing proper Westergaard stress function and using the periodicity of the hyperbolic function, the antiplane problem of the periodic parallel cracks degenerates into an algebra problem. Using the complex variable function method and the undetermined coefficients method, as well as with the help of boundary conditions, the boundary value problem of partial differential equation can be solved, and the analytic expressions for stress intensity factor, stress, and displacement near the periodical parallel cracks tip are obtained. When the cracks spacing tends to infinity, the antiplane problem of the periodic parallel cracks degenerates into the case of the antiplane problem of a single central crack
A Spatial-Temporal Dual-Mode Mixed Flow Network for Panoramic Video Salient Object Detection
Salient object detection (SOD) in panoramic video is still in the initial
exploration stage. The indirect application of 2D video SOD method to the
detection of salient objects in panoramic video has many unmet challenges, such
as low detection accuracy, high model complexity, and poor generalization
performance. To overcome these hurdles, we design an Inter-Layer Attention
(ILA) module, an Inter-Layer weight (ILW) module, and a Bi-Modal Attention
(BMA) module. Based on these modules, we propose a Spatial-Temporal Dual-Mode
Mixed Flow Network (STDMMF-Net) that exploits the spatial flow of panoramic
video and the corresponding optical flow for SOD. First, the ILA module
calculates the attention between adjacent level features of consecutive frames
of panoramic video to improve the accuracy of extracting salient object
features from the spatial flow. Then, the ILW module quantifies the salient
object information contained in the features of each level to improve the
fusion efficiency of the features of each level in the mixed flow. Finally, the
BMA module improves the detection accuracy of STDMMF-Net. A large number of
subjective and objective experimental results testify that the proposed method
demonstrates better detection accuracy than the state-of-the-art (SOTA)
methods. Moreover, the comprehensive performance of the proposed method is
better in terms of memory required for model inference, testing time,
complexity, and generalization performance
Spatial Images Feature Extraction Based on Bayesian Nonlocal Means Filter and Improved Contourlet Transform
Spatial images are inevitably mixed with different levels of noise and distortion. The contourlet transform can provide multidimensional sparse representations of images in a discrete domain. Because of its filter structure, the contourlet transform is not translation-invariant. In this paper, we use a nonsubsampled pyramid structure and a nonsubsampled directional filter to achieve multidimensional and translation-invariant image decomposition for spatial images. A nonsubsampled contourlet transform is used as the basis for an improved Bayesian nonlocal means (NLM) filter for different frequencies. The Bayesian model adds a sigma range in image a priori operations, which can be more effective in protecting image details. The NLM filter retains the image edge content and assigns greater weight to similarities for edge pixels. Experimental results both on standard images and spatial images confirm that the proposed algorithm yields significantly better performance than nonsubsampled wavelet transform, contourlet, and curvelet approaches
Affective Affordance of Message Balloon Animations: An Early Exploration of AniBalloons
We introduce the preliminary exploration of AniBalloons, a novel form of chat
balloon animations aimed at enriching nonverbal affective expression in
text-based communications. AniBalloons were designed using extracted motion
patterns from affective animations and mapped to six commonly communicated
emotions. An evaluation study with 40 participants assessed their effectiveness
in conveying intended emotions and their perceived emotional properties. The
results showed that 80% of the animations effectively conveyed the intended
emotions. AniBalloons covered a broad range of emotional parameters, comparable
to frequently used emojis, offering potential for a wide array of affective
expressions in daily communication. The findings suggest AniBalloons' promise
for enhancing emotional expressiveness in text-based communication and provide
early insights for future affective design.Comment: Accepted by CSCW 2023 poste
Genome Sequencing Reveals Unique Mutations in Characteristic Metabolic Pathways and the Transfer of Virulence Genes between V. mimicus and V. cholerae
Vibrio mimicus, the species most similar to V. cholerae, is a microbe present in the natural environmental and sometimes causes diarrhea and internal infections in humans. It shows similar phenotypes to V. cholerae but differs in some biochemical characteristics. The molecular mechanisms underlying the differences in biochemical metabolism between V. mimicus and V. cholerae are currently unclear. Several V. mimicus isolates have been found that carry cholera toxin genes (ctxAB) and cause cholera-like diarrhea in humans. Here, the genome of the V. mimicus isolate SX-4, which carries an intact CTX element, was sequenced and annotated. Analysis of its genome, together with those of other Vibrio species, revealed extensive differences within the Vibrionaceae. Common mutations in gene clusters involved in three biochemical metabolism pathways that are used for discrimination between V. mimicus and V. cholerae were found in V. mimicus strains. We also constructed detailed genomic structures and evolution maps for the general types of genomic drift associated with pathogenic characters in polysaccharides, CTX elements and toxin co-regulated pilus (TCP) gene clusters. Overall, the whole-genome sequencing of the V. mimicus strain carrying the cholera toxin gene provides detailed information for understanding genomic differences among Vibrio spp. V. mimicus has a large number of diverse gene and nucleotide differences from its nearest neighbor, V. cholerae. The observed mutations in the characteristic metabolism pathways may indicate different adaptations to different niches for these species and may be caused by ancient events in evolution before the divergence of V. cholerae and V. mimicus. Horizontal transfers of virulence-related genes from an uncommon clone of V. cholerae, rather than the seventh pandemic strains, have generated the pathogenic V. mimicus strain carrying cholera toxin genes
Streptococcus suis serotype 2 strains isolated in Argentina (South America) are different from those recovered in North America and present a higher risk for humans
Introduction: Streptococcus suis serotype 2 is an important swine pathogen and emerging zoonotic agent causing meningitis and septicemia/septic shock. Strains are usually virulent (Eurasia) or of intermediate/low virulence (North America). Very few data regarding human and swine isolates from South America are available.
Case presentation: Seventeen new human S. suis cases in Argentina (16 serotype 2 strains and a serotype 5 strain) are reported. Alongside, 14 isolates from pigs are analyzed: 12 from systemic disease, one from lungs and one from tonsils of a healthy animal. All human serotype 2 strains and most swine isolates are sequence type (ST) 1, as determined by multilocus sequence typing and present a mrp+/epf+/sly + genotype typical of virulent Eurasian ST1 strains. The remaining two strains (recovered from swine lungs and tonsils) are ST28 and possess a mrp+/epf − /sly− genotype typical of low virulence North American strains. Representative human ST1 strains as well as one swine ST28 strain were analyzed by whole-genome sequencing and compared with genomes from GenBank. ST1 strains clustered together with three strains from Vietnam and this cluster is close to another one composed of 11 strains from the United Kingdom.
Conclusion: Close contact with pigs/pork products, a good surveillance system, and the presence of potentially virulent Eurasian-like serotype 2 strains in Argentina may be an important factor contributing to the higher number of human cases observed. In fact, Argentina is now fifth among Western countries regarding the number of reported human cases after the Netherlands, France, the UK and Poland.EEA Marcos JuárezFil: Callejo, Raquel. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Han, Zheng. National Institute for Communicable Disease Control and Prevention. Chinese Center for Disease Control. State Key Laboratory for Infectious Disease Prevention and Control. Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases; ChinaFil: Pengcheng, Du. Beijing Ditan Hospital. Institute of Infectious Diseases.Capital Medical University. Beijing Key Laboratory of Emerging Infectious Diseases; ChinaFil: Prieto, Monica. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Jianguo, Xu. National Institute for Communicable Disease Control and Prevention. Chinese Center for Disease Control. State Key Laboratory for Infectious Disease Prevention and Control. Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases; ChinaFil: Zielinski, Gustavo Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; ArgentinaFil: Auger, Jean-Philippe. University of Montreal. Faculty of Veterinary Medicine. Swine and Poultry Infectious Disease Center (CRIPA); CanadaFil: Gottschalk, Marcelo. University of Montreal. Faculty of Veterinary Medicine. Swine and Poultry Infectious Disease Center (CRIPA); Canad
The oyster genome reveals stress adaptation and complexity of shell formation
The Pacific oyster Crassostrea gigas belongs to one of the most species-rich but genomically poorly explored phyla, the Mollusca. Here we report the sequencing and assembly of the oyster genome using short reads and a fosmid-pooling strategy, along with transcriptomes of development and stress response and the proteome of the shell. The oyster genome is highly polymorphic and rich in repetitive sequences, with some transposable elements still actively shaping variation. Transcriptome studies reveal an extensive set of genes responding to environmental stress. The expansion of genes coding for heat shock protein 70 and inhibitors of apoptosis is probably central to the oyster's adaptation to sessile life in the highly stressful intertidal zone. Our analyses also show that shell formation in molluscs is more complex than currently understood and involves extensive participation of cells and their exosomes. The oyster genome sequence fills a void in our understanding of the Lophotrochozoa. © 2012 Macmillan Publishers Limited. All rights reserved
Steroids as an adjunct for reducing the incidence of proliferative vitreoretinopathy after rhegmatogenous retinal detachment surgery: a systematic review and meta-analysis
BACKGROUND: This meta-analysis was performed to determine the effectiveness of steroids as an adjunct following rhegmatogenous retinal detachment (RRD) surgery. METHODS: RRD patients with or without proliferative vitreoretinopathy (PVR) were included. The treatment group included patients in whom steroids were used as an adjunct and a control group in which placebo was used. Only randomized controlled trials were included. We searched the main electronic databases and included studies published until July 2014. PVR odds ratio, visual acuity, retinal reattachment rate, and complications were evaluated in three trials. RESULTS: Three randomized controlled trials were included in the meta-analysis. There was no significant difference in the incidence of postoperative PVR between groups (heterogeneity I(2)=48%, P=0.14). However, the incidence of postoperative PVR was lower in the treatment group (I(2)=0%, P<0.0001) than in the control group when a PVR grade C study was excluded. There was no statistically significant difference in postoperative visual acuity between the treatment and control groups (odds ratio −0.18; 95% confidence interval −0.38, 0.02; P=0.08). The two groups had similar results for primary/final retinal reattachment and reoperation rate. There was no significant difference in postoperative intraocular pressure. CONCLUSION: This systematic review demonstrates that steroids may significantly reduce the incidence of postoperative PVR grade B or lower following RRD surgery
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