One-way or two-way factor model for matrix sequences?

This paper investigates the issue of determining the dimensions of row and column factor spaces in matrix-valued data. Exploiting the eigen-gap in the spectrum of sample second moment matrices of the data, we propose a family of randomised tests to check whether a one-way or two-way factor structure exists or not. Our tests do not require any arbitrary thresholding on the eigenvalues, and can be applied with (virtually) no restrictions on the relative rate of divergence of the cross-sections to the sample sizes as they pass to infinity. Although tests are based on a randomisation which does not vanish asymptotically, we propose a de-randomised, “strong” (based on the Law of the Iterated Logarithm) decision rule to choose in favour or against the presence of common factors. We use the proposed tests and decision rule in two ways. We further cast our individual tests in a sequential procedure whose output is an estimate of the number of common factors. Our tests are built on two variants of the sample second moment matrix of the data: one based on a row (or column) “flattened” version of the matrix-valued sequence, and one based on a projection-based method. Our simulations show that both procedures work well in large samples and, in small samples, the one based on the projection method delivers a superior performance compared to existing methods in virtually all cases considered.</p

Online Change-point Detection for Matrix-valued Time Series with Latent Two-way Factor Structure

This paper proposes a novel methodology for the online detectionof changepoints in the factor structure of large matrix time series. Ourapproach is based on the well-known fact that, in the presence of achangepoint, the number of spiked eigenvalues in the second momentmatrix of the data increases (e.g., in the presence of a change in theloadings, or if a new factor emerges). Based on this, we propose twofamilies of procedures - one based on the fluctuations of partial sums,and one based on extreme value theory - to monitor whether the firstnon-spiked eigenvalue diverges after a point in time in the monitoringhorizon, thereby indicating the presence of a changepoint. Our proce-dure is based only on rates; at each point in time, we randomise theestimated eigenvalue, thus obtaining a normally distributed sequencewhich isi.i.d.with mean zero under the null of no break, whereasit diverges to positive infinity in the presence of a changepoint. Webase our monitoring procedures on such sequence. Extensive simula-tion studies and empirical analysis justify the theory. An R packageimplementing the procedure is available on CRAN.</p

Frictional Effect of Helical Pile Installation in Uniform Clays

The application of helical piles offshore has been attractive due to its 'quiet' installation and retrieving potential, which makes it more environmentally friendly and economical. In this paper, single large plate helical piles in uniform clays are studied for offshore applications. The torsional installation of the helical piles is simulated using three-dimensional large deformation finite element (LDFE) analysis with Coupled Eulerian Largrangian (CEL) method in ABAQUS. The effects of interface friction between the helical pile and the clay are studied on the required torque and crowd force during torsional installations. It is found that the friction coefficient has minimal influence on the installation crowd force but has a greater influence on the installation torque required. The increased installation torque due to frictional effect can be formulated as a linear function of the friction coefficient at a given normalized penetration depth. The soil flow mechanism around the helical plate is revealed to explain the frictional effects. To provide more insight, complementary small strain analysis is conducted studying helix end effects modelled as a strip footing. The effects of plate embedment depth (H) and the soil undrained shear strength (su) on helical pile installation responses are also studied. In flat plate end bearing capacity study, the horizontal plate end bearing factor (Nc) is similar to that of vertical plate end bearing factor with embedment ratio of H/t =20

Activation maps for patient AL2.

<p>(A) Noninvasively imaged AFL reentry circuit from one single beat. Solid black lines represent propagation wavefronts in RA. (B) Average AFL reentry circuit. (C) CARTO activation map. AFL = Atrial flutter; IVC = Inferior vena cava; LA = Left atrium; MA = Mitral annulus; RA = Right atrium; SVC = Superior vena cava; TA = Tricuspid annulus.</p

UNC50 Prompts G1/S Transition and Proliferation in HCC by Regulation of Epidermal Growth Factor Receptor Trafficking

<div><p>Background</p><p>UNC50 has long been recognized as a Golgi apparatus protein in yeast, and is involved in nicotinic receptor trafficking in <i>Caenorhabditis elegans</i>, but little is known about <i>UNC50</i> gene function in human biology despite it being conserved from yeast to high eukaryotes.</p><p>Objectives</p><p>We investigated the relation between UNC50 and human hepatocellular carcinoma (HCC) and the potential mechanisms underlying HCC development.</p><p>Methods</p><p><i>UNC50</i> mRNA expression patterns in 12 HCC and adjacent non-cancerous tissues determined using northern blotting were confirmed by real-time PCR in another 44 paired tissues. Microarray experiments were used to screen for global effects of UNC50 knockdown in the Hep3B cell line, and were confirmed by real-time PCR, western blotting, flow cytometry, and tetrazolium assay in both UNC50 overexpression and knockdown Hep3B cells.</p><p>Results</p><p>UNC50 expression levels were upregulated in HCC tissues in comparison with the adjacent non-cancerous tissues. UNC50 knockdown reduced mRNA levels of the downstream targets of the epidermal growth factor receptor (EGFR) pathway: cyclin D1 (<i>CCND1</i>), <i>EGF</i>, matrix metalloproteinase-7 (<i>MMP7</i>), aldose reductase-like 1 (<i>AKR1B10</i>), cell surface–associated mucin 1 (<i>MUC1</i>), and gastrin (<i>GAST</i>). Moreover, UNC50 influenced EGF, inducing cell cycle entry by affecting cell surface EGFR amounts.</p><p>Conclusions</p><p><i>UNC50</i> may plays some roles in HCC progression by affecting the EGFR pathway.</p></div

RLIM negatively regulates c-Myc transcriptional activity.

<p>(A) 293T cells were transfected with an E-box-luciferase (Firefly) reporter plasmid and a Renilla luciferase plasmid (as an internal control) together with c-Myc and RLIM plasmids as indicated. Firefly luciferase activity was measured and normalized by Renilla luciferase activity. Three independent experiments were conducted with similar results and one representative result is shown. Data is presented as mean ± SD. **p<0.01, ***p<0.001. (B) and (C) U2OS cells were transfected with c-Myc and RLIM plasmids as indicated (B) or with siRNAs against RLIM (C). Real-time PCR was carried out to examine <i>E2F2</i> and <i>Nucleolin</i> gene expression. Three independent experiments were conducted with similar results and one representative result is shown. Data is presented as mean ± SD. *p<0.05, **p<0.01, ***p<0.001. (D) RLIM overexpression and control stable U2OS cell lines were transfected with scramble or c-Myc siRNAs. 2 days after transfection, cells were plated in 96 well plates. Cell growth were monitored by cell counting kit-8. (E) U2OS cells were transfected with scramble siRNA or siRNAs against RLIM and/or c-Myc as indicated. 2 days after transfection, cells were plated in 96 well plates. Cell growth were monitored by cell counting kit-8. Three independent experiments were conducted with similar results and one representative result is shown. Data shown is relative cell number as compared to day 1 after plating. Data is presented as mean ± SD. *p<0.05, ***p<0.001. Lower WB figures show the expression of RLIM and c-Myc at day 3 after plating. (F) H1299 cells were transfected with scramble siRNA or siRNAs against RLIM and/or c-Myc as indicated. 2 days after transfection, cells were plated in 96 well plates. Cell growth were monitored by cell counting kit-8. Three independent experiments were conducted with similar results and one representative result is shown. Data shown is relative cell number as compared to day 1 after plating. Data is presented as mean ± SD. **p<0.01. Lower WB figure show the expression of RLIM and c-Myc at day 4 after plating.</p

Results with recording sites covering a full chamber.

<p><b>First column:</b> Imaged activation time maps. <b>Second column:</b> Endocardial surface of 3D ARI maps. <b>Third column:</b> Three cross section views of 3D ARI maps. <b>Fourth column:</b> Interpolated CARTO ARI maps. Yellow stars in the ARI maps represent the longest ARI sites. All the maps were color-coded from red to blue. 3D = 3-dimensional; ARI = activation recovery interval; CC = correlation coefficient; LE = localization error; LV = left ventricle; RV = right ventricle.</p

Schematic diagram of the present study.

<p>BSPM = Body surface potential map.</p

Gmh1p interaction partners in yeast.

<p>*Interactions were evident in two independent experiments.</p><p>**Interactions were evident in at least three independent experiments.</p><p>Gmh1p interaction partners in yeast.</p

Flow cytometry and immunofluorescence analyses of EGFR distribution.

<p>(A, B) Cells not treated with 0.05% Triton X-100 before antibody staining, (C, D) Cells permeabilized by 0.05% Triton X-100 before antibody staining. Isotype rabbit immunoglobulin G (IgG) was used as the negative control. (E) Cells were stained for EGFR with Alexa 488-conjugated EGFR antibody and visualized under a fluorescence microscope at 488 nm excitation light. Scale bar is 10 μm.</p