8 research outputs found

    Multivariate-Sign-Based High-Dimensional Tests for the Two-Sample Location Problem

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    <p>This article concerns tests for the two-sample location problem when data dimension is larger than the sample size. Existing multivariate-sign-based procedures are not robust against high dimensionality, producing tests with Type I error rates far away from nominal levels. This is mainly due to the biases from estimating location parameters. We propose a novel test to overcome this issue by using the “leave-one-out” idea. The proposed test statistic is scalar-invariant and thus is particularly useful when different components have different scales in high-dimensional data. Asymptotic properties of the test statistic are studied. Compared with other existing approaches, simulation studies show that the proposed method behaves well in terms of sizes and power. Supplementary materials for this article are available online.</p

    A one-sided refined symmetrized data aggregation approach to robust mutual fund selection

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    We consider the problem of identifying skilled funds among a large number of candidates under the linear factor pricing models containing both observable and latent market factors. Motivated by the existence of non-strong potential factors and diversity of error distribution types of the linear factor pricing models, we develop a distribution-free multiple testing procedure to solve this problem. The proposed procedure is established based on the statistical tool of symmetrized data aggregation, which makes it robust to the strength of potential factors and distribution type of the error terms. We then establish the asymptotic validity of the proposed procedure in terms of both the false discovery rate and true discovery proportion under some mild regularity conditions. Furthermore, we demonstrate the advantages of the proposed procedure over some existing methods through extensive Monte Carlo experiments. In an empirical application, we illustrate the practical utility of the proposed procedure in the context of selecting skilled funds, which clearly has much more satisfactory performance than its main competitors.</p

    The Phoenix-like Noble Metal: Cu

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    Copper is one of the least reactive metals under atmospheric conditions. By heating copper in air to hundreds of degrees centigrade, its surface is oxidized to black CuO. Interestingly, the black CuO surface layer peels off automatically when the temperature of the sample is lowered to room temperature. Three-dimensional red self-assembled Cu<sub>2</sub>O nanostructures are observed in the new exposed surface (this phenomenon is compared to a phoenix reborn from the ashes). A simple extension of the spinodal decomposition to single phase system is proposed to account quantitatively for the self-assembled behavior of Cu<sub>2</sub>O nanostructures. The presented analysis is also useful to understand similar behaviors of other single phase systems

    Visual results of scale factor <i>η</i>.

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    Visual results of scale factor η.</p

    Quantitative comparisons results for CRPGAN ablations study in terms of SIFID.

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    The best scores are in bold.</p

    Autophagic Protein Beclin 1 Serves as an Independent Positive Prognostic Biomarker for Non-Small Cell Lung Cancer

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    <div><p>Beclin 1, a key regulator of autophagy, has been found to be aberrantly expressed in a variety of human malignancies. Herein, we employed immunohistochemistry (IHC) to detect the protein expression of Beclin 1 in non-small cell lung cancer (NSCLC) and paired normal adjacent lung tissues, and analyzed its clinicopathological/prognostic significance in NSCLC. Receiver operating characteristic (ROC) curve analysis was utilized to determine a cutoff point (>2 VS. ≤2) for Beclin 1 expression in a training set (n = 105). For validation, the ROC-derived cutoff value was subjected to analysis of the association of Beclin 1 with patients’ clinical characteristics and outcome in a testing set (n = 111) and the overall patient cohort (n = 216). Our data showed that Beclin 1 was significantly lower in NSCLC tissues compared with the adjacent normal tissues, negatively associating with tumor recurrence rate (65.8% VS 32.3%; <i>p</i> < 0.001). In the testing set and the overall patient cohort, low expression of Beclin 1 showed significantly inferior overall survival (OS) (<i>p</i> < 0.001) and progression-free survival (PFS) (<i>p</i> < 0.001) compared to high expression of Beclin 1. In the testing set and the overall patient cohort, the median duration of OS for patients with high and low expression of <i>Beclin 1</i> was 108 VS. 24.5 months (<i>p</i> < 0.001) and 108 VS. 28 months (<i>p</i> < 0.001), respectively. Furthermore, low expression of <i>Beclin 1</i> was also a poor prognostic factor within each stage of NSCLC patients. Multivariate analysis identified that <i>Beclin 1</i> was an independent prognostic factor for NSCLC. Our findings in the present study provided evidence that Beclin 1 may thus emerge as an independent prognostic biomarker in this tumor entity in the future. </p> </div

    Kaplan-Meier survival analysis of <i>Beclin 1</i> expression in the testing set and the overall patient cohort.

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    <p>(A) Low expression of <i>Beclin 1</i> was closely correlated with poor overall survival and (B) progression-free survival in the testing set (n = 111). (C) Patients with lower <i>Beclin 1</i> expression also acquired an inferior overall survival and (D) progression-free survival in the the overall patient cohort (n = 216). In the testing set and the overall patient cohort, the median duration of overall survival for patients with high and low expression of <i>Beclin 1</i> was 108 VS. 24.5 months (<i>p</i> < 0.001) and 108 VS.28 months (<i>p</i> < 0.001), respectively.</p

    ROC curves analysis of <i>Beclin 1</i> cutoff score.

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    <p>(A) and (B) showed the <i>Beclin 1</i> cutoff points for overall survival and progression-free survival in the training set. At each immunohistochemical score, the sensitivity and specificity for the outcome being studied was plotted, thus generating a ROC curve. The cutoff point of <i>Beclin 1</i> for overall survival and progression-free survival was 2.7 and 2.9 respectively.</p