21,511 research outputs found

    Visualizing 1D Regression

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    Regression is the study of the conditional distribution of the response y given the predictors x. In a 1D regression, y is independent of x given a single linear combination βTx of the predictors. Special cases of 1D regression include multiple linear regression, binary regression and generalized linear models. If a good estimate ˆb of some non-zero multiple cβ of β can be constructed, then the 1D regression can be visualized with a scatterplot of ˆbTx versus y. A resistant method for estimating cβ is presented along with applications

    Consistency Problems for Jump-Diffusion Models

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    In this paper consistency problems for multi-factor jump-diffusion models, where the jump parts follow multivariate point processes are examined. First the gap between jump-diffusion models and generalized Heath-Jarrow-Morton (HJM) models is bridged. By applying the drift condition for a generalized arbitrage-free HJM model, the consistency condition for jump-diffusion models is derived. Then we consider a case in which the forward rate curve has a separable structure, and obtain a specific version of the general consistency condition. In particular, a necessary and sufficient condition for a jump-diffusion model to be affine is provided. Finally the Nelson-Siegel type of forward curve structures is discussed. It is demonstrated that under regularity condition, there exists no jump-diffusion model consistent with the Nelson-Siegel curves.Comment: To appear in Applied Mathematical Financ

    Performance analysis of a flux-concentrating field-modulated permanent-magnet machine for direct-drive applications

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    Cloning and bioinformatics analysis of an ubiquitin gene of the rice stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae)

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    Ubiquitin which has the function of selective protein degradation may play an important role in the regulation of insect growth and development. The coding sequence of an ubiquitin gene from the larvae of the rice stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae) named CsUB (GenBank Accession No. GU238420) was cloned by RT-PCR and sequenced in this study, with primers according to the sequences of ubiquitin genes  from Homo sapiens, Drosophila melanogaster and Lepidopteran insects. Sequence analysis showed that the length of the coding sequence is 228 bp, encoding 76 amino acids with calculated molecular weight of 8.50 kDa and the theoretical isoeletric point of 5.26. Signal sequence and transmembrane domain had not been found. Multiple sequence alignment indicated that CsUB gene sequence with other known gene sequences of invertebrates and vertebrates had a high degree of homology (more than 72% similarity) and a shorter genetic distance (lower than 0.360). During the genetic diversity analysis, the total of 104 polymorphic sites was detected from 18 ubiquitin gene sequences and 18 haplotypes were sorted. Abundant genetic diversity and strong codon usage bias were found by the haplotype diversity (1.000), average number of nucleotide differences (47.475), nucleotide diversity (0.20866), effective number of codons (44.526), codon bias index (0.559) and scaled Chi-square (0.779). The predicated secondary structure composition of CsUB protein had about 32.89% extended strands, 36.84% random colis, 15.79% alpha helixes and 14.47% beta turns. Subcellular localization analysis showed that CsUB protein of cytoplasm, cell nucleus, mitochondrion, cell skeleton and plasma membrane occupied about 47.80, 26.10, 17.40, 4.30 and 4.30%, respectively. Sequence, homology and structural analysis confirmed that CsUB gene was highly conserved during evolution and belonged to ubiquitin gene family. The results might provide some fundamental data for further studies on expressed characteristics and physiological functions of CsUB gene.Key words: Chilo suppressalis Walker, ubiquitin, gene cloning, bioinformatics

    Upconversion Nanoparticle-Based Cell Membrane-Coated cRGD Peptide Bioorthogonally Labeled Nanoplatform for Glioblastoma Treatment

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    Glioblastoma is hard to be eradicated partly because of the obstructive blood-brain barrier (BBB) and the dynamic autophagy activities of glioblastoma. Here, hydroxychloroquine (HDX)-loaded yolk-shell upconversion nanoparticle (UCNP)@Zn0.5Cd0.5S nanoparticle coating with the cyclic Arg-Gly-Asp (cRGD)-grafted glioblastoma cell membrane for near-infrared (NIR)-triggered treatment of glioblastoma is prepared for the first time. [email protected] (abbreviated as YSN, yolk-shell nanoparticle) under NIR radiation will generate reactive oxygen species for imposing cytotoxicity. HDX, the only available autophagy inhibitor in clinical studies, can enhance cytotoxicity by preventing damaged organelles from being recycled. The cRGD-decorated cell membrane allowed the HDX-loaded nanoparticles to efficiently bypass the BBB and specifically target glioblastoma cells. Exceptional treatment efficacy of the NIR-triggered chemotherapy and photodynamic therapy was achieved in U87 cells and in the mouse glioblastoma model as well. Our results provided proof-of-concept evidence that HDX@YSN@CCM@cRGD could overcome the delivery barriers and achieve targeted treatment of glioblastoma

    Optimal self-assembly of finite shapes at temperature 1 in 3D

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    Working in a three-dimensional variant of Winfree's abstract Tile Assembly Model, we show that, for an arbitrary finite, connected shape X⊂Z2X \subset \mathbb{Z}^2, there is a tile set that uniquely self-assembles into a 3D representation of a scaled-up version of XX at temperature 1 in 3D with optimal program-size complexity (the "program-size complexity", also known as "tile complexity", of a shape is the minimum number of tile types required to uniquely self-assemble it). Moreover, our construction is "just barely" 3D in the sense that it only places tiles in the z=0z = 0 and z=1z = 1 planes. Our result is essentially a just-barely 3D temperature 1 simulation of a similar 2D temperature 2 result by Soloveichik and Winfree (SICOMP 2007)

    Hypnosis in pediatrics: applications at a pediatric pulmonary center

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    BACKGROUND: This report describes the utility of hypnosis for patients who presented to a Pediatric Pulmonary Center over a 30 month period. METHODS: Hypnotherapy was offered to 303 patients from May 1, 1998 – October 31, 2000. Patients offered hypnotherapy included those thought to have pulmonary symptoms due to psychological issues, discomfort due to medications, or fear of procedures. Improvement in symptoms following hypnosis was observed by the pulmonologist for most patients with habit cough and conversion reaction. Improvement of other conditions for which hypnosis was used was gauged based on patients' subjective evaluations. RESULTS: Hypnotherapy was associated with improvement in 80% of patients with persistent asthma, chest pain/pressure, habit cough, hyperventilation, shortness of breath, sighing, and vocal cord dysfunction. When improvement was reported, in some cases symptoms resolved immediately after hypnotherapy was first employed. For the others improvement was achieved after hypnosis was used for a few weeks. No patients' symptoms worsened and no new symptoms emerged following hypnotherapy. CONCLUSIONS: Patients described in this report were unlikely to have achieved rapid improvement in their symptoms without the use of hypnotherapy. Therefore, hypnotherapy can be an important complementary therapy for patients in a pediatric practice

    The momentum analyticity of two-point correlators from perturbation theory and AdS/CFT

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    The momentum plane analyticity of two point function of a relativistic thermal field theory at zero chemical potential is explored. A general principle regarding the location of the singularities is extracted. In the case of the N=4 supersymmetric Yang-Mills theory at large NcN_c, a qualitative change in the nature of the singularity (branch points versus simple poles) from the weak coupling regime to the strong coupling regime is observed with the aid of the AdS/CFT correspondence.Comment: 18 pages, 3 figures, typos fixed, 1 figure update

    An epidemiologic study of early biologic effects of benzene in Chinese workers.

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    Benzene is a recognized hematotoxin and leukemogen, but its mechanisms of action in humans are still uncertain. To provide insight into these processes, we carried out a cross-sectional study of 44 healthy workers currently exposed to benzene (median 8-hr time-weighted average; 31 ppm), and unexposed controls in Shanghai, China. Here we provide an overview of the study results on peripheral blood cells levels and somatic cell mutation frequency measured by the glycophorin A (GPA) gene loss assay and report on peripheral cytokine levels. All peripheral blood cells levels (i.e., total white blood cells, absolute lymphocyte count, platelets, red blood cells, and hemoglobin) were decreased among exposed workers compared to controls, with the exception of the red blood cell mean corpuscular volume, which was higher among exposed subjects. In contrast, peripheral cytokine levels (interleukin-3, interleukin-6, erythropoietin, granulocyte colony-stimulating factor, tissue necrosis factor-alpha) in a subset of the most highly exposed workers (n = 11) were similar to values in controls (n = 11), suggesting that benzene does not affect these growth factor levels in peripheral blood. The GPA assay measures stem cell or precursor erythroid cell mutations expressed in peripheral red blood cells of MN heterozygous subjects, identifying NN variants, which result from loss of the GPA M allele and duplication of the N allele, and N phi variants, which arise from gene inactivation. The NN (but not N phi) GPA variant cell frequency was elevated in the exposed workers compared with controls (mean +/- SD, 13.9 +/- 8.4 mutants per million cells versus 7.4 +/- 5.2 per million cells, (respectively; p = 0.0002), suggesting that benzene produces gene-duplicating but not gene-inactivating mutations at the GPA locus in bone marrow cells of exposed humans. These findings, combined with ongoing analyses of benzene macromolecular adducts and chromosomal aberrations, will provide an opportunity to comprehensively evaluate a wide range of early biologic effects associated with benzene exposure in humans
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