588 research outputs found
SOME CONTRIBUTIONS TO THE CENSORED EMPIRICAL LIKELIHOOD WITH HAZARD-TYPE CONSTRAINTS
Empirical likelihood (EL) is a recently developed nonparametric method of statistical inference. Owen’s 2001 book contains many important results for EL with uncensored data. However, fewer results are available for EL with right-censored data. In this dissertation, we first investigate a right-censored-data extension of Qin and Lawless (1994). They studied EL with uncensored data when the number of estimating equations is larger than the number of parameters (over-determined case). We obtain results similar to theirs for the maximum EL estimator and the EL ratio test, for the over-determined case, with right-censored data. We employ hazard-type constraints which are better able to handle right-censored data. Then we investigate EL with right-censored data and a k-sample mixed hazard-type constraint. We show that the EL ratio test statistic has a limiting chi-square distribution when k = 2. We also study the relationship between the constrained Kaplan-Meier estimator and the corresponding Nelson-Aalen estimator. We try to prove that they are asymptotically equivalent under certain conditions. Finally we present simulation studies and examples showing how to apply our theory and methodology with real data
The Comparison of American and Chinese Family Education: Taking Modern Family as an Example
This paper compares some important family education phenomena in the TV serial--Modern Family which are obviously different in China. Then, this paper gives explanation from three main perspectives of beliefs, historical as well as welfare origin. And some implications are provided so as to help Chinese parents cast off obsolete thoughts and support all-round development of Chinese children
Three new species of Cymbella (Bacillariophyta) from high altitude lakes, China
This paper describes three new Cymbella species from high altitude lakes of Hengduan Mountains region, southwest China. Cymbella heihainensis Li et Gong nov.spec. is similar to C. modicepunctata Krammer, C. asiatica Metzeltin, Lange-Bertalot et Li, Y., but differs from them in valve size, stigmata, raphe ending and also striae number. Cymbella shudunensis Li et Metzeltin nov. spec. is related to C. terrafuegiana, but differs in wider valve size, larger central area and coarser puncta. C. shudunensis differs from C. proxima Reimer in Patrick et Reimer group in reverse lateral raphes at the proximal endings, and distinguished from C. cistula (Ehrenberg) O.Kirchner group in the absent central area on dorsal side. Cymbella xingyunnensis Li and Gong sp. nov. resembles the group around C. proxima, and the most similar taxon is C. sinensis Metzeltn et Krammer,which can be distinguished by its lack of stigmata
Research on Multi-Dimensional Dynamic Clustering Method of Big Data Alliance Users
In order to improve the clustering accuracy of big data alliance users, this paper studies users\u27 dynamic clustering based on their multi-dimensional attributes. First of all, the user profile of big data alliance is constructed from five dimensions of user basic attribute, domain attribute, preference attribute, social attribute and value attribute. And the K-means algorithm is used to cluster user profiles to complete the initial clustering. Then, based on the group user profile, combined with the user\u27s recent dynamic behavior data, the FCM algorithm is used to achieve secondary clustering. Finally, the proposed user clustering method is tested by recommending data resources to the clustered user groups. The experimental results show that the user clustering method proposed in this paper has higher accuracy and lower error rate
An implementation of nDGP gravity in Pinocchio
In this paper we investigate dark matter structure formation in the normal
branch of the Dvali-Gabadadze-Porrati (nDGP) model using the PINOCCHIO
algorithm. We first present 2nd order Lagrangian perturbation theory for the
nDGP model, which shows that the 1st- and 2nd-order growth functions in nDGP
are larger than those in {\Lambda}CDM. We then examine the dynamics of
ellipsoidal collapse in nDGP, which is accelerated compared to {\Lambda}CDM due
to enhanced gravitational interactions. Running the nDGP-PINOCCHIO code with a
box size of 512 Mpc/h and 1024*1024*1024 particles, we analyze the statistical
properties of the output halo catalogs, including the halo power spectrum and
halo mass function. The calibrated PINOCCHIO halo power spectrum agrees with
N-body simulations within 5% in the comoving wavenumber range k < 0.3 (h/Mpc)
at redshift z = 0. The agreement is extended to smaller scales for higher
redshifts. For the cumulative halo mass function, the agreement between N-body
and PINOCCHIO is also within the simulation scatter.Comment: 18 pages, 3 figure
Multiobjective Transmission Network Planning considering the Uncertainty and Correlation of Wind Power
In order to consider the uncertainty and correlation of wind power in multiobjective transmission network expansion planning (TNEP), this paper presents an extended point-estimation method to calculate the probabilistic power flow, based on which the correlative power outputs of wind farm are sampled and the uncertain multiobjective transmission network planning model is transformed into a solvable deterministic model. A modified epsilon multiobjective evolutionary algorithm is used to solve the above model and a well-distributed Pareto front is achieved, and then the final planning scheme can be obtained from the set of nondominated solutions by a fuzzy satisfied method. The proposed method only needs the first four statistical moments and correlation coefficients of the output power of wind farms as input information; the modeling of wind power is more precise by considering the correlation between wind farms, and it can be easily combined with the multiobjective transmission network planning model. Besides, as the self-adaptive probabilities of crossover and mutation are adopted, the global search capabilities of the proposed algorithm can be significantly improved while the probability of being stuck in the local optimum is effectively reduced. The accuracy and efficiency of the proposed method are validated by IEEE 24 as well as a real system
Discovery of multiple lead compounds as M2 inhibitors through the focused screening of a small primary amine library.
The discovery of new anti-influenza drugs is urgent, particularly considering the recent threat of swine flu. In this study, the influenza virus M2 protein was expressed in HEK293 cells and shown to have selective ion channel activity for monovalent ions. The anti-influenza virus drug amantadine hydrochloride significantly attenuated the inward current induced by hyperpolarization of HEK293 cell membranes. Although adamantine derivatives are the only M2 drugs for influenza virus A, their use is limited in the US due to drug resistance. Here we report the discovery of multiple M2 inhibitor lead compounds that were rapidly generated through focused screening of a small primary amine library. The screen was designed using a scaffold-hopping strategy based on amantadine. This study suggests that an antiviral compound directed against a conserved motif may be more useful than amantadine in inhibiting viral replication
Patterns of MicroRNA Expression in Normal and Early Alzheimer\u27s Disease Human Temporal Cortex: White Matter versus Gray Matter
MicroRNA (miRNA) expression was assessed in human cerebral cortical gray matter (GM) and white matter (WM) in order to provide the first insights into the difference between GM and WM miRNA repertoires across a range of Alzheimer\u27s disease (AD) pathology. RNA was isolated separately from GM and WM portions of superior and middle temporal cerebral cortex (N = 10 elderly females, postmortem interval \u3c 4 h). miRNA profiling experiments were performed using state-of-the-art Exiqon© LNA-microarrays. A subset of miRNAs that appeared to be strongly expressed according to the microarrays did not appear to be conventional miRNAs according to Northern blot analyses. Some well-characterized miRNAs were substantially enriched in WM as expected. However, most of the miRNA expression variability that correlated with the presence of early AD-related pathology was seen in GM. We confirm that downregulation of a set of miRNAs in GM (including several miR-15/107 genes and miR-29 paralogs) correlated strongly with the density of diffuse amyloid plaques detected in adjacent tissue. A few miRNAs were differentially expressed in WM, including miR-212 that is downregulated in AD and miR-424 which is upregulated in AD. The expression of certain miRNAs correlates with other miRNAs across different cases, and particular subsets of miRNAs are coordinately expressed in relation to AD-related pathology. These data support the hypothesis that patterns of miRNA expression in cortical GM may contribute to AD pathogenetically, because the aggregate change in miRNA expression observed early in the disease would be predicted to cause profound changes in gene expression
An experimental study on the rotational accuracy of variable preload spindle-bearing system
The rotational performance of the spindle-bearing system has critical influence upon the geometric shape and surface roughness of the machined parts. The effects of preload and preload method on the rotational performance of the spindle-bearing system is explored experimentally to reveal the role of preload and preload method in spindle rotational performances under different speeds. A test rig on which both the rigid preload and elastic preload can be realized, equipped with variable preload spindle-bearing system, is developed. Based on the mechanical model, the relationship of the axial preload and negative axial clearance of the spindle-bearing system is provided. Rotating sensitive radial error motion tests are conducted for evaluating synchronous and asynchronous radial errors of the variable preload spindle-bearing system under different rotating speeds and preload methods. The change regularity of synchronous and asynchronous radial errors with preloads under different rotating speeds are given. The results show that the preload plays an important role on the rotational performance of spindle-bearing system. The rigid preload is more efficient in achieving better rotational performance than elastic preload under the same rotating speed. Furthermore, this article significantly guides the preload designing and assembling of the new spindle-bearing system
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