Wasserstein Regression

The analysis of samples of random objects that do not lie in a vector space is gaining increasing attention in statistics. An important class of such object data is univariate probability measures defined on the real line. Adopting the Wasserstein metric, we develop a class of regression models for such data, where random distributions serve as predictors and the responses are either also distributions or scalars. To define this regression model, we utilize the geometry of tangent bundles of the space of random measures endowed with the Wasserstein metric for mapping distributions to tangent spaces. The proposed distribution-to-distribution regression model provides an extension of multivariate linear regression for Euclidean data and function-to-function regression for Hilbert space valued data in functional data analysis. In simulations, it performs better than an alternative transformation approach where one maps distributions to a Hilbert space through the log quantile density transformation and then applies traditional functional regression. We derive asymptotic rates of convergence for the estimator of the regression operator and for predicted distributions and also study an extension to autoregressive models for distribution-valued time series. The proposed methods are illustrated with data on human mortality and distributional time series of house prices

Model Aerodynamic Tests with a Wire-driven Parallel Suspension System in Low-speed Wind Tunnel

AbstractOwing to the advantages of wire-driven parallel manipulator, a new wire-driven parallel suspension system for airplane model in low-speed wind tunnel is constructed, and the methods to measure and calculate the aerodynamic parameters of the airplane model are studied. In detail, a static model of the wire-driven parallel suspension is analyzed, a mathematical model for describing the aerodynamic loads exerted on the scale model is constructed and a calculation method for obtaining the aerodynamic parameters of the model by measuring the tension of wires is presented. Moreover, the measurement system for wire tension and its corresponding data acquisition system are designed and built. Thereafter, the wire-driven parallel suspension system is placed in an open return circuit low-speed wind tunnel for wind tunnel tests to acquire data of each wire tension when the airplane model is at different attitudes and different wind speeds. A group of curves about the parameters for aerodynamic load exerted on the airplane model are obtained at different wind speeds after the acquired data are analyzed. The research results validate the feasibility of using a wire-driven parallel manipulator as the suspension system for low-speed wind tunnel tests

In vivo99mTc-HYNIC-annexin V imaging of early tumor apoptosis in mice after single dose irradiation

<p>Abstract</p> <p>Background</p> <p>Apoptosis is a major mode of hematological tumor death after radiation. Early detection of apoptosis may be beneficial for cancer adaptive treatment. ^99mTc-HYNIC-annexinV has been reported as a promising agent for in vivo apoptosis imaging. The purpose of this study is to evaluate the feasibility of in vivo^99mTc-HYNIC-annexinV imaging of radiation- induced apoptosis, and to investigate its correlation with radiosensitivity.</p> <p>Methods</p> <p>Ten days after inoculation of tumor cells in the right upper limbs, the mice were randomly divided into two groups. The imaging group (4 mice each level, 4 dose levels) was injected with 4-8 MBq ^99mTc-HYNIC-annexinV 24 hours after irradiation and imaged 1 hr post-injection, and the mice were sacrificed immediately after imaging for biodistribution analysis of annexin V. The observation group (4 mice each level, 2 dose levels) was only observed for tumor regression post-radiation. The number of apoptotic cells in a tumor was estimated with TUNEL assay.</p> <p>Results</p> <p>The ^99mTc-HYNIC-annexin V uptake in E14 lymphoma significantly increased as the radiation dose escalated from 0 to 8 Gy, and significantly correlated with the number of TUNEL-positive cells (r = 0.892, P < 0.001). The Annexin-V uptake and the number of TUNEL-positive cells in El4 lymphoma were significantly greater than those in S180 sarcoma. With 8 Gy, S180 sarcoma tumor showed scanty apoptosis and less shrinkage while El4 lymphoma showed remarkable apoptosis and complete remission.</p> <p>Conclusion</p> <p>⁹⁹mTc-HYNIC-annexinV in vivo imaging is a feasible method to detect early radiation-induced apoptosis in different tumors, and might be predictive for radiation sensitivity.</p

Graph pangenome captures missing heritability and empowers tomato breeding

Missing heritability in genome-wide association studies defines a major problem in genetic analyses of complex biological traits(1,2). The solution to this problem is to identify all causal genetic variants and to measure their individual contributions(3,4). Here we report a graph pangenome of tomato constructed by precisely cataloguing more than 19 million variants from 838 genomes, including 32 new reference-level genome assemblies. This graph pangenome was used forgenome-wide association study analyses and heritability estimation of 20,323 gene-expression and metabolite traits. The average estimated trait heritability is 0.41 compared with 0.33 when using the single linear reference genome. This 24% increase in estimated heritability is largely due to resolving incomplete linkage disequilibrium through the inclusion of additional causal structural variants identified using the graph pangenome. Moreover, by resolving allelic and locus heterogeneity, structural variants improve the power to identify genetic factors underlying agronomically important traits leading to, for example, the identification of two new genes potentially contributing to soluble solid content. The newly identified structural variants will facilitate genetic improvement of tomato through both marker-assisted selection and genomic selection. Our study advances the understanding of the heritability of complex traits and demonstrates the power of the graph pangenome in crop breeding

Political networking strategy and firm performance: a moderated mediation model

Purpose By incorporating the resource-based view with the dynamic capability view, this study aims to examine the link between corporate political networking strategy and firm performance in transition economies by focusing on the mediating role of corporate entrepreneurship and the moderating role of dysfunctional competition. Design/methodology/approach A large-scale questionnaire survey was conducted among 1,300 senior managers from 650 enterprises in China, and valid survey data were obtained from 401 enterprises. Findings Empirical results demonstrate that political networking strategy is positively related to firm performance and that this relationship is fully mediated by corporate entrepreneurship. Moderated path analysis indicates that dysfunctional competition strengthens the direct effect of political networking strategy on corporate entrepreneurship and its indirect effect on firm performance via corporate entrepreneurship. Originality/value This research is among the first to examine the mediating mechanism underlying the relationship between political networking strategy and firm performance in the context of transition economies. In addition, existing research has seldom discussed the effects on corporate entrepreneurship of external resource acquisition from government sources. This research fills this important gap and identifies the condition under which political networking benefits corporate entrepreneurship

SalK/SalR, a Two-Component Signal Transduction System, Is Essential for Full Virulence of Highly Invasive Streptococcus suis Serotype 2

BACKGROUND: Streptococcus suis serotype 2 (S. suis 2, SS2) has evolved into a highly infectious entity, which caused the two recent large-scale outbreaks of human SS2 epidemic in China, and is characterized by a toxic shock-like syndrome. However, the molecular pathogenesis of this new emerging pathogen is still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: 89K is a newly predicted pathogenicity island (PAI) which is specific to Chinese epidemic strains isolated from these two SS2 outbreaks. Further bioinformatics analysis revealed a unique two-component signal transduction system (TCSTS) located in the candidate 89K PAI, which is orthologous to the SalK/SalR regulatory system of Streptococcus salivarius. Knockout of salKR eliminated the lethality of SS2 in experimental infection of piglets. Functional complementation of salKR into the isogenic mutant DeltasalKR restored its soaring pathogenicity. Colonization experiments showed that the DeltasalKR mutant could not colonize any susceptible tissue of piglets when administered alone. Bactericidal assays demonstrated that resistance of the mutant to polymorphonuclear leukocyte (PMN)-mediated killing was greatly decreased. Expression microarray analysis exhibited a transcription profile alteration of 26 various genes down-regulated in the DeltasalKR mutant. CONCLUSIONS/SIGNIFICANCE: These findings suggest that SalK/SalR is requisite for the full virulence of ethnic Chinese isolates of highly pathogenic SS2, thus providing experimental evidence for the validity of this bioinformatically predicted PAI

Einfluss der Verarbeitungstechnologie und Werkstoffzusammensetzung auf die Struktur-Eigenschafts-Beziehungen von thermoplastischen Nanoverbundwerkstoffen

Die Einarbeitung von nanoskaligen Füllstoffen zur Steigerung von polymeren Eigenschaftsprofilen ist sehr viel versprechend und stößt daher heutzutage sowohl in der Forschung als auch in der Industrie auf großes Interesse. Bedingt durch ausgeprägte Oberflächen und hohe Anziehungskräfte, liegen Nanopartikel allerdings nicht singulär sondern als Partikelanhäufungen, so genannten Agglomeraten oder Aggregaten, vor. Zur Erzielung der gewünschten Materialverbesserungen gilt es, diese aufzuspalten und homogen in der polymeren Matrix zu verteilen. Bei thermoplastischen Kunststoffen ist die gleichläufige Doppelschneckenextrusion eines der gängigsten Verfahren zur Einarbeitung von Additiven und Füllstoffen. Aus diesem Grund war es Ziel dieser Arbeit, mittels dieses Verfahrens verbesserte Verbundwerkstoffe mit Polyamid 66- und Polyetheretherketon-Matrix, durch Einarbeitung von nanoskaligem Titandioxid (15 und 300 nm), zu generieren. In einem ersten Schritt wurden die verfahrenstechnischen Parameter, wie Drehzahl und Durchsatz, sowie die Prozessführung und damit deren Einfluss auf die Materialeigenschaften beleuchtet. Der spezifische Energieeintrag ist ausschlaggebend zur Deagglomeration der Nanopartikel. Dieser zeigte leichte Abhängigkeiten von der Drehzahl und dem Durchsatz und verursachte bei der Einarbeitung der Partikel keine wesentlichen Unterschiede in der Aufspaltung der Partikel sowie gar keine in den resultierenden mechanischen Eigenschaften. Die Prozessführung wurde unterteilt in Mehrfach- und Einfachextrusion. Die Herstellung eines hochgefüllten Masterbatches, dessen mehrfaches Extrudieren und anschließendes Verdünnen, führte zu einer sehr guten Deagglomeration und stark verbesserten Materialeigenschaften. Mittels Simulation des Extrusionsprozesses konnte festgestellt werden, dass das Vorhandensein von ungeschmolzenem Granulat in der Verfahrenszone zu einer Schmelze/Nanopartikel/ Feststoffreibung führt, die die Ursache für eine sehr gute Aufspaltung der Partikel zu sein scheint. Durch Modifikation des Extrusionsprozesses erreichte die Einfachextrusion annähernd den Grad an Deagglomeration bei Mehrfachextrusion, wobei die Materialien bei letzterem Verfahren die besten Eigenschaftsprofile aufwiesen. In einem zweiten Schritt wurde ein Vergleich der Einflüsse von unterschiedlichen Partikelgrößen und –gehalten auf die polymeren Matrizes vollzogen. Die 15 nm Partikel zeigten signifikant bessere mechanische Ergebnisse auf als die 300 nm Partikel, und die Wirkungsweise des 15 nm Partikels auf Polyetheretherketon war stärker als auf Polyamid 66. Es konnten Steigerungen in Steifigkeit, Festigkeit und Zähigkeit erzielt werden. Rasterelektronenmikroskopische Aufnahmen bestätigten diese Ergebnisse. Eine Berechnung der Plan-Selbstkosten von einem Kilogramm PEEK-Nanoverbundwerkstoff im Vergleich zu einem Kilogramm unverstärktem PEEK verdeutlichte, dass ein Material kreiert wurde, welches deutlich verbesserte Eigenschaften bei gleichem Preis aufweist. Zusammenfassend konnte in dieser Arbeit ein tieferes Verständnis des Extrusionsvorganges zur Herstellung von kostengünstigen und verbesserten Thermoplasten durch das Einbringen von Nanopartikeln gewonnen werden

Application of Ultrafiltration and Ion Exchange Separation Technology for Lysozyme Separation and Extraction

In this study, the fermentation broth of the recombinant Pichia pastoris strain ncy-2 was studied. After pretreatment, separation, and purification, lysozyme was optimized using biofilm and ion exchange separation. Finally, lysozyme dry enzyme powder was prepared by concentrating and vacuum drying. The removal rate of bacterial cells was 99.99% when the fermentation broth was centrifuged at low temperature. The optimum conditions were: transmembrane pressure of 0.20 MPa, pH 6.5, 96.6% yield of lysozyme, enzyme activity of 2612.1 u/mg, which was 1.78 times higher than that of the original enzyme; D152 resin was used for adsorption and elution. Process conditions were optimized: the volume ratio of resin to liquid was 15%; the adsorption time was 4 h; the concentration of NaCl was 1.0 mol/L; the recovery rate of lysozyme activity was 95.67%; the enzyme activity was 3879.6 u/mL; and the purification multiple was 0.5, 3.1 times of the original enzyme activity. The enzyme activity of lysozyme dry enzyme powder was 12,573.6 u/mg, which had an inhibitory effect on microsphere lysozyme. Its enzymatic properties were almost the same as those of natural lysozyme, which demonstrated good application prospects and production potential