112 research outputs found

    THE LOCAL DENSITY AND THE LOCAL WEAK DENSITY IN THE SPACE OF PERMUTATION DEGREE AND IN HATTORI SPACE

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    In this paper, the local density (ld)(l d) and the local weak density (lwd)(l w d) in the space of permutation degree as well as the cardinal and topological properties of Hattori spaces are studied. In other words, we study the properties of the functor of permutation degree SPnS P^{n} and the subfunctor of permutation degree SPGnS P_{G}^{n}PP is the cardinal number of topological spaces. Let XX be an infinite T1T_{1}-space. We prove that the following propositions hold.(1) Let YnXnY^{n} \subset X^{n}; (A) if d(Yn)=d(Xn)d\, \left(Y^{n} \right)=d\, \left(X^{n} \right), then d(SPnY)=d(SPnX)d\, \left(S P^{n} Y\right)=d\, \left(SP^{n} X\right); (B) if lwd(Yn)=lwd(Xn)l w d\, \left(Y^{n} \right)=l w d\, \left(X^{n} \right), then lwd(SPnY)=lwd(SPnX)l w d\, \left(S P^{n} Y\right)=l w d\, \left(S P^{n} X\right). (2) Let YXY\subset X; (A) if ld(Y)=ld(X)l d \,(Y)=l d \,(X), then ld(SPnY)=ld(SPnX)l d\, \left(S P^{n} Y\right)=l d\, \left(S P^{n} X\right); (B) if wd(Y)=wd(X)w d \,(Y)=w d \,(X), then wd(SPnY)=wd(SPnX)w d\, \left(S P^{n} Y\right)=w d\, \left(S P^{n} X\right).(3) Let nn be a positive integer, and let GG be a subgroup of the permutation group SnS_{n}. If XX is a locally compact T1T_{1}-space, then SPnX,SPGnXS P^{n} X, \, S P_{G}^{n} X, and expnX\exp _{n} X are kk-spaces.(4) Let nn be a positive integer, and let GG be a subgroup of the permutation group SnS_{n}. If XX is an infinite T1T_{1}-space, then nπw(X)=nπw(SPnX)=nπw(SPGnX)=nπw(expnX)n \,\pi \,w \left(X\right)=n \, \pi \,w \left(S P^{n} X \right)=n \,\pi \,w \left(S P_{G}^{n} X \right)=n \,\pi \,w \left(\exp _{n} X \right).We also have studied that the functors SPn,SP^{n}, SPGn,SP_{G}^{n} , and expn\exp _{n} preserve any kk-space. The functors SP2SP^{2} and SPG3SP_{G}^{3} do not preserve Hattori spaces on the real line. Besides, it is proved that the density of an infinite T1T_{1}-space XX coincides with the densities of the spaces XnX^{n}, SPnX\,S P^{n} X, and expnX\exp _{n} X. It is also shown that the weak density of an infinite T1T_{1}-space XX coincides with the weak densities of the spaces XnX^{n}, SPnX\,S P^{n} X, and expnX\exp _{n} X

    Delikli Kompozit Yapıların Sonlu Elemanlar Yöntemiyle Analizi

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    Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Burada delikli ileri kompozit yapılarda hasarın doğru tahmini için yapılan bir çalışmanın sonuçları sunulmuştur. Çalışmanın ilk bölümünde, kullanılan kompozitlerin ilgili mekanik özelliklerini belirlemek için kupon ve çatlak ilerleme testlerinden oluşan bir malzeme test programı yürütülmüştür. Daha sonra, delikli kompozit yapıları incelemek için bir sonlu elemanlar analizi modeli oluşturulmuştur. Sürekli ortam kabuk elemanları (continuum shell) kullanarak delaminasyonu (tabaka ayrılmasını) hesaba katan ve katmayan sonlu eleman modelleri oluşturuldu. Gerçekçi bir simülasyon elde edebilmek için ilerlemeli hasar analizi yapılmıştır. En uygun modeli belirlemek amacıyla, test sonuçları ve simülasyonlardan elde edilen sonuçlar ayrıntılı olarak tartışılmıştır.The results of a study for the prediction of failure behavior in advanced composite structures with holes are presented here. In the first part of the study, a materials test program based on coupon and fracture tests is conducted to obtain related mechanical properties. A finite element model is then constructed for simulating the behavior of advanced composite laminates with hole under tension. Two finite element models using continuum shell elements, one with and the other without the delamination failure were developed. In order to have a realistic simulation, the progressive failure analysis is applied. For an optimum model, test results and simulation results are discussed, thoroughly

    Learning Foveated Reconstruction to Preserve Perceived Image Statistics

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    Foveated image reconstruction recovers full image from a sparse set of samples distributed according to the human visual system's retinal sensitivity that rapidly drops with eccentricity. Recently, the use of Generative Adversarial Networks was shown to be a promising solution for such a task as they can successfully hallucinate missing image information. Like for other supervised learning approaches, also for this one, the definition of the loss function and training strategy heavily influences the output quality. In this work, we pose the question of how to efficiently guide the training of foveated reconstruction techniques such that they are fully aware of the human visual system's capabilities and limitations, and therefore, reconstruct visually important image features. Due to the nature of GAN-based solutions, we concentrate on the human's sensitivity to hallucination for different input sample densities. We present new psychophysical experiments, a dataset, and a procedure for training foveated image reconstruction. The strategy provides flexibility to the generator network by penalizing only perceptually important deviations in the output. As a result, the method aims to preserve perceived image statistics rather than natural image statistics. We evaluate our strategy and compare it to alternative solutions using a newly trained objective metric and user experiments

    The Local Density and the Local Weak Density in the Space of Permutation Degree and in Hattori Space

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    In this paper, the local density (ld) and the local weak density (lwd) in the space of permutation degree as well as the cardinal and topological properties of Hattori spaces are studied. In other words, we study the properties of the functor of permutation degree SPn and the subfunctor of permutation degree SPnG, P is the cardinal number of topological spaces. Let X be an infinite T1-space. We prove that the following propositions hold. (1) Let Yn⊂Xn; (A) if d(Yn)=d(Xn), then d(SPnY)=d(SPnX); (B) if lwd(Yn)=lwd(Xn), then lwd(SPnY)=lwd(SPnX). (2) Let Y⊂X; (A) if ld(Y)=ld(X), then ld(SPnY)=ld(SPnX); (B) if wd(Y)=wd(X), then wd(SPnY)=wd(SPnX). (3) Let n be a positive integer, and let G be a subgroup of the permutation group Sn. If X is a locally compact T1-space, then SPnX,SPnGX, and expnX are k-spaces. (4) Let n be a positive integer, and let G be a subgroup of the permutation group Sn. If X is an infinite T1-space, then nπw(X)=nπw(SPnX)=nπw(SPnGX)=nπw(expnX). We also have studied that the functors SPn, SPnG, and expn preserve any k-space. The functors SP2 and SP3G do not preserve Hattori spaces on the real line. Besides, it is proved that the density of an infinite T1-space X coincides with the densities of the spaces Xn, SPnX, and expnX. It is also shown that the weak density of an infinite T1-space X coincides with the weak densities of the spaces Xn, SPnX, and expnX

    HOT or not: examining the basis of high-occupancy target regions

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    High-occupancy target (HOT) regions are segments of the genome with unusually high number of transcription factor binding sites. These regions are observed in multiple species and thought to have biological importance due to high transcription factor occupancy. Furthermore, they coincide with house-keeping gene promoters and consequently associated genes are stably expressed across multiple cell types. Despite these features, HOT regions are solemnly defined using ChIP-seq experiments and shown to lack canonical motifs for transcription factors that are thought to be bound there. Although, ChIP-seq experiments are the golden standard for finding genome-wide binding sites of a protein, they are not noise free. Here, we show that HOT regions are likely to be ChIP-seq artifacts and they are similar to previously proposed 'hyper-ChIPable' regions. Using ChIP-seq data sets for knocked-out transcription factors, we demonstrate presence of false positive signals on HOT regions. We observe sequence characteristics and genomic features that are discriminatory of HOT regions, such as GC/CpG-rich k-mers, enrichment of RNA-DNA hybrids (R-loops) and DNA tertiary structures (G-quadruplex DNA). The artificial ChIP-seq enrichment on HOT regions could be associated to these discriminatory features. Furthermore, we propose strategies to deal with such artifacts for the future ChIP-seq studies

    Conductive cotton prepared by polyaniline in situ polymerization using laccase

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    The high-redox-potential catalyst laccase, isolated from Aspergillus, was first used as a biocatalyst in the oxidative polymerization of water-soluble conductive polyaniline, and then conductive cotton was prepared by in situ polymerization under the same conditions. The polymerization of aniline was performed in a water dispersion of sodium dodecylbenzenesulfonate (SDBS) micellar solution with atmospheric oxygen serving as the oxidizing agent. This method is ecologically clean and permits a greater degree of control over the kinetics of the reaction. The conditions for polyaniline synthesis were optimized. Characterizations of the conducting polyaniline and cotton were carried out using Fourier transform infrared spectroscopy, UV–vis spectroscopy, cyclic voltammetry, the fabric induction electrostatic tester, and the far-field EMC shielding effectiveness test fixture.This work was financially supported by the National Natural Science Foundation of China (21274055, 51173071), the Program for New Century Excellent Talents in University (NCET-12-0883), the Natural Science Foundation of Jiangsu Province (BK2011157), the Fundamental Research Funds for the Central Universities (JUSRP51312B), and the Program for Changjiang Scholars and Innovative Research Team in University (IRT1135)

    A Toolkit and Robust Pipeline for the Generation of Fosmid-Based Reporter Genes in C. elegans

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    Engineering fluorescent proteins into large genomic clones, contained within BACs or fosmid vectors, is a tool to visualize and study spatiotemporal gene expression patterns in transgenic animals. Because these reporters cover large genomic regions, they most likely capture all cis-regulatory information and can therefore be expected to recapitulate all aspects of endogenous gene expression. Inserting tags at the target gene locus contained within genomic clones by homologous recombination (“recombineering”) represents the most straightforward method to generate these reporters. In this methodology paper, we describe a simple and robust pipeline for recombineering of fosmids, which we apply to generate reporter constructs in the nematode C. elegans, whose genome is almost entirely covered in an available fosmid library. We have generated a toolkit that allows for insertion of fluorescent proteins (GFP, YFP, CFP, VENUS, mCherry) and affinity tags at specific target sites within fosmid clones in a virtually seamless manner. Our new pipeline is less complex and, in our hands, works more robustly than previously described recombineering strategies to generate reporter fusions for C. elegans expression studies. Furthermore, our toolkit provides a novel recombineering cassette which inserts a SL2-spliced intercistronic region between the gene of interest and the fluorescent protein, thus creating a reporter controlled by all 5′ and 3′ cis-acting regulatory elements of the examined gene without the direct translational fusion between the two. With this configuration, the onset of expression and tissue specificity of secreted, sub-cellular compartmentalized or short-lived gene products can be easily detected. We describe other applications of fosmid recombineering as well. The simplicity, speed and robustness of the recombineering pipeline described here should prompt the routine use of this strategy for expression studies in C. elegans

    A Genome-Wide RNAi Screen for Factors Involved in Neuronal Specification in Caenorhabditis elegans

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    One of the central goals of developmental neurobiology is to describe and understand the multi-tiered molecular events that control the progression of a fertilized egg to a terminally differentiated neuron. In the nematode Caenorhabditis elegans, the progression from egg to terminally differentiated neuron has been visually traced by lineage analysis. For example, the two gustatory neurons ASEL and ASER, a bilaterally symmetric neuron pair that is functionally lateralized, are generated from a fertilized egg through an invariant sequence of 11 cellular cleavages that occur stereotypically along specific cleavage planes. Molecular events that occur along this developmental pathway are only superficially understood. We take here an unbiased, genome-wide approach to identify genes that may act at any stage to ensure the correct differentiation of ASEL. Screening a genome-wide RNAi library that knocks-down 18,179 genes (94% of the genome), we identified 245 genes that affect the development of the ASEL neuron, such that the neuron is either not generated, its fate is converted to that of another cell, or cells from other lineage branches now adopt ASEL fate. We analyze in detail two factors that we identify from this screen: (1) the proneural gene hlh-14, which we find to be bilaterally expressed in the ASEL/R lineages despite their asymmetric lineage origins and which we find is required to generate neurons from several lineage branches including the ASE neurons, and (2) the COMPASS histone methyltransferase complex, which we find to be a critical embryonic inducer of ASEL/R asymmetry, acting upstream of the previously identified miRNA lsy-6. Our study represents the first comprehensive, genome-wide analysis of a single neuronal cell fate decision. The results of this analysis provide a starting point for future studies that will eventually lead to a more complete understanding of how individual neuronal cell types are generated from a single-cell embryo
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