224 research outputs found
A General Model on Intertemporal Measure Correlation
In this paper, we proposed the error growth curve model for the integration of intertemporal measure errors correlation which usually exist in quality control process. This model can work well in the usual error distributions, such as normal, uniform, Rayleigh and some other error distributions. Simulation results show that the proposed estimators of the model parameters perform well especially in small sample situations
Estimation of parameters in the growth curve model via an outer product least squares approach for covariance
AbstractIn this paper, we propose a framework of outer product least squares for covariance (COPLS) to directly estimate covariance in the growth curve model based on an analogy, between the outer product of a data vector and covariance of a random vector, and the ordinary least squares technique. The COPLS estimator of covariance has an explicit expression and is shown to have the following properties: (1) following a linear transformation of two independent Wishart distribution for a normal error matrix; (2) having asymptotic normality for a nonnormal error matrix; and (3) having unbiasedness and invariance under a linear transformation group. And, a corresponding two-stage generalized least squares (GLS) estimator for the regression coefficient matrix in the model is obtained and its asymptotic normality is investigated. Simulation studies confirm that the COPLS estimator and the two-stage GLS estimator of the regression coefficient matrix are satisfying competitors with some evident merits to the existing maximum likelihood estimator in finite samples
Poly[di-μ9-citrato-cobalt(II)tetrasodium]
The title compound, [CoNa4(C6H5O7)2]n, was obtained under hydrothermal conditions as a minor product. The Co2+ cation is located on a crystallographic inversion center and is coordinated by six O atoms from two different citrate units, forming a [Co(C6H5O7)2]4− building unit with Co—O bond lengths between 2.0578 (17) and 2.0813 (16) Å. The structure features two crystallographically independent Na+ ions. The first Na+ cation is five-coordinated by O atoms of five carboxylate groups from four different citrate anions. The second Na+ cation is surrounded by six O atoms of five carboxylate groups from five different citrate anions. The carboxylate groups of the citrate are completely deprononated, the hydroxyl group, however, is not. It is coordinated to the Co2+ cation, and through an O—H⋯O hydrogen bond connected to a neighboring [Co(C6H5O7)2]4− building unit. The coordination modes of the carboxylate O atoms vary, with one O atom being coordinated to three different Na+ cations, three are bridging O atoms bound to two Na+ cations and two are connected to a Co2+ cation and a Na+ cation, respectively. Through these interconnections, the basic [Co(C6H5O7)2]4− building units are linked with each other through coordination of their carboxylate groups to the Na+ cations, forming a three-dimensional framework
The Contribution of Geomagnetic Activity to Polar Ozone Changes in the Upper Atmosphere
Energetic particle precipitation (EPP) has significant impacts on ozone depletion in the polar middle atmosphere during geomagnetic activity. It is well known that solar ultraviolet (UV) radiation plays an important role in ozone generation. Therefore, it is interesting to compare the contributions of EPP and solar UV to ozone changes in the polar upper atmosphere. In this article, we use the annual average Ap index to denote the annual-mean magnitude of the geomagnetic activity, which is closely correlated with the EPP flux, and the annual average F10.7 index to denote the annual-mean magnitude of the solar radiation, which is somewhat related to the solar UV. We adopt the 5° zonal annual-mean ozone profile dataset to study the statistical characters between the ozone dataset and the Ap, F10.7 indices. Multiple regression analysis shows that the contributions of geomagnetic activity are not negligible and are of a similar order of magnitude as the solar UV radiation in the polar upper atmosphere (above 10 hPa). The results also show that high-speed solar-wind-stream-induced and coronal-mass-ejection-driven geomagnetic activity is of the same order of magnitude. There are interhemispheric differences according to our multiple regression analysis. We discuss the possible causes of these differences
Gene therapy with tumor-specific promoter mediated suicide gene plus IL-12 gene enhanced tumor inhibition and prolonged host survival in a murine model of Lewis lung carcinoma
<p>Abstract</p> <p>Background</p> <p>Gene therapy is a promising therapeutic approach for cancer. Targeted expression of desired therapeutic proteins within the tumor is the best approach to reduce toxicity and improve survival. This study is to establish a more effective and less toxic gene therapy of cancer.</p> <p>Methods</p> <p>Combined gene therapy strategy with recombinant adenovirus expressing horseradish peroxidase (HRP) mediated by human telomerase reverse transcriptase (hTERT) promoter (AdhTERTHRP) and murine interleukin-12 (mIL-12) under the control of Cytomegalovirus (CMV) promoter (AdCMVmIL-12) was developed and evaluated against Lewis lung carcinoma (LLC) both <it>in vivo </it>and <it>in vitro</it>. The mechanism of action and systemic toxicities were also investigated.</p> <p>Results</p> <p>The combination of AdhTERTHRP/indole-3-acetic acid (IAA) treatment and AdCMVmIL-12 resulted in significant tumor growth inhibition and survival improvement compared with AdhTERTHRP/IAA alone (tumor volume, 427.4 ± 48.7 mm<sup>3 </sup><it>vs </it>581.9 ± 46.9 mm<sup>3</sup>, <it>p </it>= 0.005 on day 15; median overall survival (OS), 51 d <it>vs </it>33 d) or AdCMVmIL-12 alone (tumor volume, 362.2 ± 33.8 mm<sup>3 </sup><it>vs </it>494.4 ± 70.2 mm<sup>3</sup>, <it>p </it>= 0.046 on day 12; median OS, 51 d <it>vs </it>36 d). The combination treatment stimulated more CD4<sup>+ </sup>and CD8<sup>+ </sup>T lymphocyte infiltration in tumors, compared with either AdCMVmIL-12 alone (1.3-fold increase for CD4<sup>+ </sup>T cells and 1.2-fold increase for CD8<sup>+ </sup>T cells, <it>P </it>< 0.01) or AdhTERTHRP alone (2.1-fold increase for CD4<sup>+ </sup>T cells and 2.2-fold increase for CD8<sup>+ </sup>T cells, <it>P </it>< 0.01). The apoptotic cells in combination group were significantly increased in comparison with AdCMVmIL-12 alone group (2.8-fold increase, <it>P </it>< 0.01) or AdhTERTHRP alone group (1.6-fold increase, <it>P </it>< 0.01). No significant systematic toxicities were observed.</p> <p>Conclusions</p> <p>Combination gene therapy with AdhTERTHRP/IAA and AdCMVmIL-12 could significantly inhibit tumor growth and improve host survival in LLC model, without significant systemic adverse effects.</p
Optimizing Hydraulic Fracturing Treatment Integrating Geomechanical Analysis and Reservoir Simulation for a Fractured Tight Gas Reservoir, Tarim Basin, China
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