Mid-Latency Auditory Evoked Potentials: Monitoring the Depth of Hypnosis in Children: MLAEP in children during anesthesia

Evaluating the performance of a mid-latency auditory evoked potentials based depth of hypnosis monitor in children receiving anesthesia.AIMS OF THIS THESIS - To assess the thoughts and opinions of (pediatric) anesthesiologists about the use of depth of hypnosis monitoring in children receiving anesthesia. - To inventory the perceived need for a reliable depth of hypnosis monitor for children. - To review the current literature concerning the use of MLAEP in children receiving anesthesia. - To evaluate the performance of the aepEX monitor in children receiving anesthesia with commonly available hypnotics

Tensor Rank Estimation and Completion via CP-based Nuclear Norm

Tensor completion (TC) is a challenging problem of recovering missing entries of a tensor from its partial observation. One main TC approach is based on CP/Tucker decomposition. However, this approach often requires the determination of a tensor rank a priori. This rank estimation problem is difficult in practice. Several Bayesian solutions have been proposed but they often under/overestimate the tensor rank while being quite slow. To address this problem of rank estimation with missing entries, we view the weight vector of the orthogonal CP decomposition of a tensor to be analogous to the vector of singular values of a matrix. Subsequently, we define a new CP-based tensor nuclear norm as the L1-norm of this weight vector. We then propose Tensor Rank Estimation based on L1-regularized orthogonal CP decomposition (TREL1) for both CP-rank and Tucker-rank. Specifically, we incorporate a regularization with CP-based tensor nuclear norm when minimizing the reconstruction error in TC to automatically determine the rank of an incomplete tensor. Experimental results on both synthetic and real data show that: 1) Given sufficient observed entries, TREL1 can estimate the true rank (both CP-rank and Tucker-rank) of incomplete tensors well; 2) The rank estimated by TREL1 can consistently improve recovery accuracy of decomposition-based TC methods; 3) TREL1 is not sensitive to its parameters in general and more efficient than existing rank estimation methods

Rank-One Matrix Completion with Automatic Rank Estimation via L1-Norm Regularization

Completing a matrix from a small subset of its entries, i.e., matrix completion is a challenging problem arising from many real-world applications, such as machine learning and computer vision. One popular approach to solve the matrix completion problem is based on low-rank decomposition/factorization. Low-rank matrix decomposition-based methods often require a prespecified rank, which is difficult to determine in practice. In this paper, we propose a novel low-rank decomposition-based matrix completion method with automatic rank estimation. Our method is based on rank-one approximation, where a matrix is represented as a weighted summation of a set of rank-one matrices. To automatically determine the rank of an incomplete matrix, we impose L1-norm regularization on the weight vector and simultaneously minimize the reconstruction error. After obtaining the rank, we further remove the L1-norm regularizer and refine recovery results. With a correctly estimated rank, we can obtain the optimal solution under certain conditions. Experimental results on both synthetic and real-world data demonstrate that the proposed method not only has good performance in rank estimation, but also achieves better recovery accuracy than competing methods

Bilinear Probabilistic Canonical Correlation Analysis via Hybrid Concatenations

Canonical Correlation Analysis (CCA) is a classical technique for two-view correlation analysis, while Probabilistic CCA (PCCA) provides a generative and more general viewpoint for this task. Recently, PCCA has been extended to bilinear cases for dealing with two-view matrices in order to preserve and exploit the matrix structures in PCCA. However, existing bilinear PCCAs impose restrictive model assumptions for matrix structure preservation, sacrificing generative correctness or model flexibility. To overcome these drawbacks, we propose BPCCA, a new bilinear extension of PCCA, by introducing a hybrid joint model. Our new model preserves matrix structures indirectly via hybrid vector-based and matrix-based concatenations. This enables BPCCA to gain more model flexibility in capturing two-view correlations and obtain close-form solutions in parameter estimation. Experimental results on two real-world applications demonstrate the superior performance of BPCCA over competing methods

Determination of Endothelial Stalk versus Tip Cell Potential during Angiogenesis by H2.0-like Homeobox-1

SummaryTissue branching morphogenesis requires the hierarchical organization of sprouting cells into leading “tip” and trailing “stalk” cells [1, 2]. During new blood vessel branching (angiogenesis), endothelial tip cells (TCs) lead sprouting vessels, extend filopodia, and migrate in response to gradients of the secreted ligand, vascular endothelial growth factor (Vegf) [3]. In contrast, adjacent stalk cells (SCs) trail TCs, generate the trunk of new vessels, and critically maintain connectivity with parental vessels. Here, we establish that h2.0-like homeobox-1 (Hlx1) determines SC potential, which is critical for angiogenesis during zebrafish development. By combining a novel pharmacological strategy for the manipulation of angiogenic cell behavior in vivo with transcriptomic analyses of sprouting cells, we identify the uniquely sprouting-associated gene, hlx1. Expression of hlx1 is almost entirely restricted to sprouting endothelial cells and is excluded from adjacent nonangiogenic cells. Furthermore, Hlx1 knockdown reveals its essential role in angiogenesis. Importantly, mosaic analyses uncover a cell-autonomous role for Hlx1 in the maintenance of SC identity in sprouting vessels. Hence, Hlx1-mediated maintenance of SC potential regulates angiogenesis, a finding that may have novel implications for sprouting morphogenesis of other tissues

Monitoring Depth of Hypnosis: Mid-Latency Auditory Evoked Potentials Derived aepEX in Children Receiving Desflurane-Remifentanil Anesthesia

BACKGROUND: The aepEXplus monitoring system, which uses mid-latency auditory evoked potentials to measure depth of hypnosis, was evaluated in pediatric patients receiving desflurane-remifentanil anesthesia. METHODS: Seventy-five patients, 1-18 years of age (stratified for age; 1-3, 3-6, 6-18 years, for subgroup analyses), were included in this prospective observational study. The aepEX and the bispectral index (BIS) were recorded simultaneously, the latter serving as a reference. The ability of the aepEX to detect different levels of consciousness, defined according to the University of Michigan Sedation Scale, investigated using prediction probability (Pk), and receiver operating characteristic (ROC) analysis, served as the primary outcome parameter. As a secondary outcome parameter, the relationship between end-tidal desflurane and the aepEX and BIS values were calculated by fitting in a nonlinear regression model. RESULTS: The Pk values for the aepEX and the BIS were, respectively, .68 (95% CI, 0.53-0.82) and .85 (95% CI, 0.73-0.96; P = .02). The aepEX and the BIS had an area under the ROC curve of, respectively, 0.89 (95% CI, 0.80-0.95) and 0.76 (95% CI, 0.68-0.84; P = .04). The maximized sensitivity and specificity were, respectively, 81% (95% CI, 61%-93%) and 86% (95% CI, 74%-94%) for the aepEX at a cutoff value of >52, and 69% (95% CI, 56%-81%) and 70% (95% CI, 57%-81%) for the BIS at a cutoff value of >65. The age-corrected end-tidal desflurane concentration associated with an index value of 50 (EC50) was 0.59 minimum alveolar concentration (interquartile range: 0.38-0.85) and 0.58 minimum alveolar concentration (interquartile range: 0.41-0.70) for, respectively, the aepEX and BIS (P = .69). Age-group analysis showed no evidence of a difference regarding the area under the ROC curve or EC50. CONCLUSIONS: The aepEX can reliably differentiate between a conscious and an unconscious state in pediatric patients receiving desflurane-remifentanil anesthesia

Persistent currents in diffusive metallic cavities: Large values and anomalous scaling with disorder

The effect of disorder on confined metallic cavities with an Aharonov-Bohm flux line is addressed. We find that, even deep in the diffusive regime, large values of persistent currents may arise for a wide variety of geometries. We present numerical results supporting an anomalous scaling law of the average typical current $$ with the strength of disorder $w$, $\sim w^{- \gamma}$ with $\gamma < 2$. This is contrasted with previously reported results obtained for cylindrical samples where a scaling $\sim w^{-2}$ has been found. Possible links to, up to date, unexplained experimental data are finally discussed.Comment: 5 pages, 4 figure

Effects of a Structured Exercise Programme on Functional Balance in Visually Impaired Elderly Living in a Residential Setting

AbstractOne major priority for health care professionals is to minimize the risk of fall in the elderly population. While the quality of life of an individual is affected by fall accidents, management of post-fall disability in the elderly could be a huge economic burden to the society. Visually impaired elderly are at a higher risk of fall, because “vision”, an important component contributing to balance, is disturbed. The aim of this study was to examine the effects of an exercise programme, which focused on improvement of the functional balance of visually impaired elderly. Visually impaired elderly residents were randomly assigned to either the exercise training or control group. A multidimensional, individually tailored exercise programme was introduced by physiotherapists to the exercise group for 12 weeks. Functional balance status reflected by the Berg Balance Scale, chair stand test, and timed up-and-go test assessed before and after the 12-week training programme was compared between the two groups. Results demonstrated a significant improvement in balance outcomes in the exercise group (p < 0.05) but not in the control group. The results of this study suggest that a physiotherapist-designed strengthening and balance-training programme can improve the functional balance status of visually impaired elderly