We investigate bag-of-visual-words (BOVW) approaches to land-use classification in high-resolution overhead imagery. We consider a standard non-spatial representation in which the frequencies but not the locations of quantized image features are used to discriminate between classes analogous to how words are used for text document classification without regard to their order of occurrence. We also consider two spatial extensions, the established spatial pyramid match kernel which considers the absolute spatial arrangement of the image features, as well as a novel method which we term the spatial co-occurrence kernel that considers the relative arrangement. These extensions are motivated by the importance of spatial structure in geographic data.The methods are evaluated using a large ground truth image dataset of 21 land-use classes. In addition to comparisons with standard approaches, we perform extensive evaluation of different configurations such as the size of the visual dictionaries used to derive the BOVW representations and the scale at which the spatial relationships are considered.We show that even though BOVW approaches do not necessarily perform better than the best standard approaches overall, they represent a robust alternative that is more effective for certain land-use classes. We also show that extending the BOVW approach with our proposed spatial cooccurrence kernel consistently improves performance.

This paper investigates local invariant features for geographic (overhead) image retrieval. Local features are particularly well suited for the newer generations of aerial and satellite imagery whose increased spatial resolution, often just tens of centimeters per pixel, allows a greater range of objects and spatial patterns to be recognized than ever before. Local invariant features have been successfully applied to a broad range of computer vision problems and, as such, are receiving increased attention from the remote sensing community particularly for challenging tasks such as detection and classification. We perform an extensive evaluation of local invariant features for image retrieval of land-use/land-cover (LULC) classes in high-resolution aerial imagery. We report on the effects of a number of design parameters on a bag-of-visual-words (BOVW) representation including saliency-versus grid-based local feature extraction, the size of the visual codebook, the clustering algorithm used to create the codebook, and the dissimilarity measure used to compare the BOVW representations. We also perform comparisons with standard features such as color and texture. The performance is quantitatively evaluated using a first-of-its-kind LULC ground truth data set which will be made publicly available to other researchers. In addition to reporting on the effects of the core design parameters, we also describe interesting findings such as the performance-efficiency tradeoffs that are possible through the appropriate pairings of different-sized codebooks and dissimilarity measures. While the focus is on image retrieval, we expect our insights to be informative for other applications such as detection and classification.Index Terms-Bag of visual words, content-based image retrieval, high-resolution overhead image analysis, land cover, land use, local invariant features, remote sensing.

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In conventional and high transition temperature copper oxide and iron pnictide superconductors, the Cooper pairs all have even parity. As a rare exception, Sr2RuO4 is the first prime candidate for topological chiral p-wave superconductivity, which has time-reversal breaking odd-parity Cooper pairs known to exist before only in the neutral superfluid 3 He. However, there are several key unresolved issues hampering the microscopic description of the unconventional superconductivity. Spin fluctuations at both large and small wavevectors are present in experiments, but how they arise and drive superconductivity is not yet clear. Spontaneous edge current is expected but not observed conclusively. Specific experiments point to highly band-and/or momentum-dependent energy gaps for quasiparticle excitations in the superconducting state. Here, by comprehensive functional renormalization group calculations with all relevant bands, we disentangle the various competing possibilities. In particular we show the small wavevector spin fluctuations, driven by a single two-dimensional band, trigger p-wave superconductivity with quasi-nodal energy gaps.PACS numbers: 74.20.Rp, 71.27.+a Very soon after the discovery of superconductivity in Sr 2 RuO 4 [1], it was proposed that the superconducting (SC) pairing is of unconventional nature [2,3]. Later experiments have provided evidence that the Cooper pair in the SC state is of odd parity [4] with total spin equal to one [5]. Further evidence indicates the superconductivity to be chiral, breaking time reversal symmetry [6,7]. Sr 2 RuO 4 is thus the first prime candidate for a chiral p-wave superconductor [8][9][10][11], an interesting analogue of the neutral superfluid 3 He. It has recently received great interest as by suitable manipulations it may support zero energy Majorana bound states in vortices [12], the building block for topological quantum computing [13]. However, there are a number of outstanding issues associated with the chiral p-wave superconductivity in Sr 2 RuO 4 . First, p-wave spin triplet pairing is expected to be associated with spin fluctuations at small wavevector. However, the spin density wave (SDW) fluctuation observed in Sr 2 RuO 4 is dominated by a large wavevector at higher temperatures and coexist with a feature at small wavevector at lower temperatures. [14] A resolution of this puzzle is vital to understand the superconductivity. Second, one would expect a spontaneous electric current at the edge of the RuO 2 layers as a result of the chiral SC state. The edge current, however, has not been observed conclusively in experiments.[15] One possible reason is the edge current is very fragile and difficult to establish against disorders. Another possibility is a topological cancellation from hole-like and electron-like bands, [16] posing a question as whether the SC state is topologically nontrivial at all. Third, the specific measurement reveals abundance of low energy quasiparticle excitations below the transition temperature. [17] This would point to mu...

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Background Duchenne Muscular Dystrophy (DMD) is the most common muscle disease in children, and there are no effective therapies for DMD or Becker Muscular Dystrophy (BMD). Currently, targeted gene therapy treatments have emerged. As a result, genetic diagnosis is the basis of treatment. In addition, genetic and prenatal diagnosis significantly reduces their incidence rates. This study combines the application of multiplex ligation-dependent probe amplification technology (MLPA) and “next-generation” sequencing technology (NGS) as the most economical and efficient method of diagnosis. Therefore, in the diagnosis of DMD/BMD, patients’ MLPA data are first used to detect DMD gene deletions or duplications, and NGS and Sanger sequencing are then applied to exclude MLPA-negative samples. Meanwhile, polymerase chain reaction (PCR) is used to detect single exon deletions to exclude false-positives in MLPA caused by point mutations. Methods In this study, we recruited 1051 proband families of DMD from 2016 to 2018 and had access to information that could identify individual participants during or after data collection. Patients who were diagnosed with DMD were first tested by MLPA. MLPA results with single exon deletions were validated with PCR amplification and Sanger sequencing. The negative results of MLPA were further analysed with NGS and validated by Sanger sequencing. For novel missense mutations, phenotype-genotype correlations were analysed using PolyPhen2 and mutation taster. All methods were performed in accordance with the relevant guidelines and regulations. Results DMD mutations were identified in 1029 families (97.91%, 1029/1051). Large deletions, duplications, and small mutations accounted for 70.41% (740/1051), 8.28% (87/1051), and 19.12% (201/1051) of all cases, respectively. There were 205 small mutation types, 53 of which were novel. The rate of de novo mutations was 39.45% (187/474) and was higher in large duplications (49.53%, 157/317). Among 68 asymptomatic patients (< 3 years old) with unexplained persistent hyperCKaemia upon conventional physical examination, 63 were diagnosed as DMD/BMD according to genetic diagnosis. Conclusion Our results expand the spectrum of DMD mutations, which could contribute to the treatment of DMD/BMD and provide an effective diagnosis method. Thus, the combination of MLPA, NGS and Sanger sequencing is of great significance for family analysis, gene diagnosis and gene therapy.

Background: TIP60 can be regulated by autoacetylation and deacetylated by SIRT1. Results: Novel lysine residues of TIP60 autoacetylation were identified, and TIP60 can be functionally regulated by HDAC3 through deacetylation. Conclusion: HDAC3 promotes TIP60 ubiquitination and cytoplasmic localization and protects cells from apoptosis after DNA damage. Significance: Our findings provide a better understanding of TIP60 regulatory mechanisms and its cellular functions.

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