Guided flows in coronal magnetic flux tubes

There is evidence for coronal plasma flows to break down into fragments and to be laminar. We investigate this effect by modeling flows confined along magnetic channels. We consider a full MHD model of a solar atmosphere box with a dipole magnetic field. We compare the propagation of a cylindrical flow perfectly aligned to the field to that of another one with a slight misalignment. We assume a flow speed of 200 km/s, and an ambient magnetic field of 30 G. We find that while the aligned flow maintains its cylindrical symmetry while it travels along the magnetic tube, the misaligned one is rapidly squashed on one side, becoming laminar and eventually fragmented because of the interaction and backreaction of the magnetic field. This model could explain an observation of erupted fragments that fall back as thin and elongated strands and end up onto the solar surface in a hedge-like configuration, made by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. The initial alignment of plasma flow plays an important role in determining the possible laminar structure and fragmentation of flows while they travel along magnetic channels.Comment: 11 pages, 8 figures, accepted for publication, movies available upon request to the first autho

総会抄録

<p>Antibody responses and protection of offspring when mothers were immunized via the IN route and their offspring via the IN route<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0157041#t004fn001" target="_blank">^a</a>.</p

Highly Efficient and Scalable Compound Decomposition of Two-Electron Integral Tensor and Its Application in Coupled Cluster Calculations

The representation and storage of two-electron integral tensors are vital in large-scale applications of accurate electronic structure methods. Low-rank representation and efficient storage strategy of integral tensors can significantly reduce the numerical overhead and consequently time-to-solution of these methods. In this work, by combining pivoted incomplete Cholesky decomposition (CD) with a follow-up truncated singular vector decomposition (SVD), we develop a decomposition strategy to approximately represent the two-electron integral tensor in terms of low-rank vectors. A systematic benchmark test on a series of 1-D, 2-D, and 3-D carbon–hydrogen systems demonstrates high efficiency and scalability of the compound two-step decomposition of the two-electron integral tensor in our implementation. For the size of the atomic basis set, <i>N</i>_<i>b</i>, ranging from ∼100 up to ∼2,000, the observed numerical scaling of our implementation shows O(Nb2.5−3) versus O(Nb3−4) cost of performing single CD on the two-electron integral tensor in most of the other implementations. More importantly, this decomposition strategy can significantly reduce the storage requirement of the atomic orbital (AO) two-electron integral tensor from O(Nb4) to O(Nb2⁡log(Nb)) with moderate decomposition thresholds. The accuracy tests have been performed using ground- and excited-state formulations of coupled cluster formalism employing single and double excitations (CCSD) on several benchmark systems including the C₆₀ molecule described by nearly 1,400 basis functions. The results show that the decomposition thresholds can be generally set to 10^–4 to 10^–3 to give acceptable compromise between efficiency and accuracy

A High-Dimensional Nonparametric Multivariate Test for Mean Vector

<p>This work is concerned with testing the population mean vector of nonnormal high-dimensional multivariate data. Several tests for high-dimensional mean vector, based on modifying the classical Hotelling <i>T</i>² test, have been proposed in the literature. Despite their usefulness, they tend to have unsatisfactory power performance for heavy-tailed multivariate data, which frequently arise in genomics and quantitative finance. This article proposes a novel high-dimensional nonparametric test for the population mean vector for a general class of multivariate distributions. With the aid of new tools in modern probability theory, we proved that the limiting null distribution of the proposed test is normal under mild conditions when <i>p</i> is substantially larger than <i>n</i>. We further study the local power of the proposed test and compare its relative efficiency with a modified Hotelling <i>T</i>² test for high-dimensional data. An interesting finding is that the newly proposed test can have even more substantial power gain with large <i>p</i> than the traditional nonparametric multivariate test does with finite fixed <i>p</i>. We study the finite sample performance of the proposed test via Monte Carlo simulations. We further illustrate its application by an empirical analysis of a genomics dataset. Supplementary materials for this article are available online.</p

Electrophilic Rearrangements of Chiral Amides: A Traceless Asymmetric α‑Allylation

A one-pot protocol for the asymmetric α-allylation reaction is reported relying on a key efficient asymmetric Claisen rearrangement, triggered by electrophilic activation of chiral pseudoephedrine amides. Subsequent reduction or hydrolysis of the resulting iminium ions provides highly enantioenriched α-allylic aldehydes or carboxylic acids in a traceless manner. Compared to traditional alternatives which make use of strongly basic conditions, the work presented herein displays unprecedented functional group tolerance

Direct Observation of the Formation of Liquid Protrusions on Polymer Colloids and their Coalescence

Monodisperse nonspherical poly (methyl methacrylate) (PMMA) particles where a central core particle had grown two extra “lobes”, or protrusions, placed opposite each other were successfully synthesized by swelling and subsequent polymerization of cross-linked PMMA spheres with methyl methacrylate and the cross-linker ethylene glycol dimethacrylate. The use of large (∼3 μm) seed particles allowed for real-time monitoring of the swelling and deswelling of the cross-linked particles with optical microscopy. First, a large number of small droplets of swelling monomers formed simultaneously on the surface of the seed particles, and then fused together until under certain conditions two protrusions remained on opposite sides of the seed particles. The yield of such particles could be made up to 90% with a polydispersity of 7.0%. Stirring accelerated the transfer of the swelling monomers to the seed particles. Stirring was also found to induce self-assembly of the swollen seed particles into a wide variety of <i>n</i>-mers, consisting of a certain number, <i>n</i>, of swollen seed particles. The formation of these structures is guided by the minimization of the interfacial free energy between the seed particles, liquid protrusions and aqueous phase, but stirring time and geometrical factors influence it as well. By inducing polymerization the structures could be made permanent. Some control over the topology as well as overall size of the clusters was achieved by varying the stirring time before polymerization. 3D models of possible particle structures were used to identify all projections of the structures obtained by scanning electron microscopy. These models also revealed that the seed particles inside the central coalesced body were slightly compressed after polymerization. By extending the synthesis of the monodisperse particles with <i>n</i> = 1 to (slightly) different monomers and/or different cores, an important class of patchy particles could be realized

The Litvinenko case and its reflection in The Daily Telegraph

This bachelor thesis studies the manner in which the case of the former Russian spy Alexander Litviněnko's poisoning was handled in 2006 by the British newspaper The Daily Telegraph. Both quantitative and qualitative analyses have been used for that purpose. The theoretical part of the thesis explains the factors influencing the process of encoding of the meanings into mediated contents, and the process of their subsequent decoding by the public. The analytical part presents a detailed description of how the concrete news texts on the Litvinenko case published by The Daily Telegraph could have been perceived by their recipient. Hypotheses have been set for the analysis; the confirmation or denial of their validity outlines The Daily Telegraph's methods of news reporting production and the terms in which the news texts are conceived in this newspaper

Direct Observation of the Formation of Liquid Protrusions on Polymer Colloids and their Coalescence

Monodisperse nonspherical poly (methyl methacrylate) (PMMA) particles where a central core particle had grown two extra “lobes”, or protrusions, placed opposite each other were successfully synthesized by swelling and subsequent polymerization of cross-linked PMMA spheres with methyl methacrylate and the cross-linker ethylene glycol dimethacrylate. The use of large (∼3 μm) seed particles allowed for real-time monitoring of the swelling and deswelling of the cross-linked particles with optical microscopy. First, a large number of small droplets of swelling monomers formed simultaneously on the surface of the seed particles, and then fused together until under certain conditions two protrusions remained on opposite sides of the seed particles. The yield of such particles could be made up to 90% with a polydispersity of 7.0%. Stirring accelerated the transfer of the swelling monomers to the seed particles. Stirring was also found to induce self-assembly of the swollen seed particles into a wide variety of <i>n</i>-mers, consisting of a certain number, <i>n</i>, of swollen seed particles. The formation of these structures is guided by the minimization of the interfacial free energy between the seed particles, liquid protrusions and aqueous phase, but stirring time and geometrical factors influence it as well. By inducing polymerization the structures could be made permanent. Some control over the topology as well as overall size of the clusters was achieved by varying the stirring time before polymerization. 3D models of possible particle structures were used to identify all projections of the structures obtained by scanning electron microscopy. These models also revealed that the seed particles inside the central coalesced body were slightly compressed after polymerization. By extending the synthesis of the monodisperse particles with <i>n</i> = 1 to (slightly) different monomers and/or different cores, an important class of patchy particles could be realized

Five-axis contour error estimation based on multi-Information dynamic time warping

No description supplied</p

Five-axis contour error estimation based on multi-Information dynamic time warping

Contour accuracy is crucial for machining precision in five-axis computer numerical control (CNC) machining. This paper addresses the challenge of improving contour accuracy by proposing a novel contour error estimation and compensation method based on dynamic time warping (DTW). By incorporating time information and geometric characteristics of the machining path, the proposed method introduces a multiple-information fusion algorithm to define distance characteristics between the planned and actual trajectory sequences. This allows the calculation of a distortion path and the establishment of a mapping model between the two sequences. To mitigate the effect of DTW singularity on contour error estimation, a mapping model is established between line segments to determine reference points. The position contour error and the direction contour error of the five-axis tool are accurately estimated using segmented Hermite interpolation, and a spatial iterative learning framework is employed to compensate for them. Experimental results demonstrate the effectiveness of the proposed method in dealing with estimation errors in complex trajectories and its good performance in improving contour accuracy. Note to Practitioners —This paper proposes an effective strategy for the estimation of contour errors in five-axis machining. Currently, most methods for contour error estimation in five-axis machining are based on the nearest point principle. However, this approach fails to accurately estimate contour errors for complex trajectories with significant curvature variations, leading to ineffective contour error compensation in subsequent stages. Therefore, we introduce a contour error estimation algorithm based on DTW. This algorithm takes into account the time information and geometric features of the machining path. Experimental results validate the feasibility and advantages of this approach.</p