cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
One-point Functions in Defect CFT and Integrability
Creators: name: de Leeuw, Marius
name: Kristjansen, Charlotte
name: Zarembo, Konstantin
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We calculate planar tree level one-point functions of non-protected operators in the defect conformal field theory dual to the D3-D5 brane system with k units of the world volume flux. Working in the operator basis of Bethe eigenstates of the Heisenberg XXX_{1/2} spin chain we express the one-point functions as overlaps of these eigenstates with a matrix product state. For k=2 we obtain a closed expression of determinant form for any number of excitations, and in the case of half-filling we find a relation with the Néel state. In addition, we present a number of results for the limiting case of infinite k.
description: 31 pages, 3 figures; v2: references added
Collective frequency variation in network synchronization and reverse PageRank
Creators: name: Skardal, Per Sebastian
name: Taylor, Dane
name: Sun, Jie
name: Arenas, Alex
Publisher: name: arXiv
Year: 2015
Subjects: subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: A wide range of natural and engineered phenomena rely on large networks of interacting units to reach a dynamical consensus state where the system collectively operates. Here we study the dynamics of self-organizing systems and show that for generic directed networks the collective frequency of the ensemble is {\it not} the same as the mean of the individuals' natural frequencies. Specifically, we show that the collective frequency equals a weighted average of the natural frequencies, where the weights are given by an out-flow centrality measure that is equivalent to a reverse PageRank centrality. Our findings uncover an intricate dependence of the collective frequency on both the structural directedness and dynamical heterogeneity of the network, and also reveal an unexplored connection between synchronization and PageRank, which opens the possibility of applying PageRank optimization to synchronization. Finally, we demonstrate the presence of collective frequency variation in real-world networks by considering the UK and Scandinavian power grids.
40 Years of Studying the Evolving Compact Radio Sources in M82
Creators: name: Muxlow, Tom
Publisher: name: Zenodo
Year: 2023

description: For over 40 years the EVN has been fundamental in the investigation of the bright supernova remnants in M82 including the nominal super nova remnant’ (SNR) 41.95+57.5 - for many years the brightest single compact radio object within M82. VLBI imaging has confirmed the unusual double-lobed structure of 41.95+57.5 which is unlike the more typical shell-like SNR found in M82. The lobe separation historically increased at a rate of ~0.24mas/yr, yielding an upper limit derived expansion age of ~100 years. 41.95+57.5 has decreased in flux density at ~8.8%/yr since L-Band monitoring began in the early 1970s until the late 1990s, indicating a potential birth 1.4GHz flux density of ~170Jy - with a luminosity approaching that of radio afterglows of long-duration gamma-ray bursts, suggesting that 41.95+57.5 may be a late stage GRB radio afterglow.
 Global VLBI confirms the double-lobed structure continues to fade, however more recently an evolving partial ring-like structure has begun to appear within the existing fading double lobes. L-Band monitoring from 1993 onwards has shown that the rate of change in total flux density of the remnant has slowed to ~6.4% / yr. In addition, e-MERLIN imaging in 2014 shows the 1.5 - 6.2GHz spectral index has flattened to ~-0.5 from -0.8 over around a 10- year period, suggesting an emerging flatter spectrum central nebula is beginning to appear, consistent. with a Pulsar Wind Nebula (PWN).
 The recent wide-field C-Band Western EVN + e-MERLIN programme (EM148, 20B013), has investigated the detailed structure of 41.95+57.5 at ~5-10mas resolution together with other compact shell-like SNR within the central 30 arcsec of the M82 nuclear region. With the additional short-spacing coverage provided by e-MERLIN antennas, the expansion of such fading shells has allowed an extension to the expansion timeline to further constrain the expansion velocity evolution of these SNR which are beginning to become highly resolved with VLBI-only investigations. New expansion velocity constraints are presented for the classical shell SNR 43.31+59.2
Relationship Induced Multi-Template Learning for Diagnosis of Alzheimer’s Disease and Mild Cognitive Impairment
Creators: name: Shen, Dinggang
name: Zhang, Daoqiang
name: Liu, Mingxia
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: As shown in the literature, methods based on multiple templates usually achieve better performance, compared with those using only a single template for processing medical images. However, most existing multi-template based methods simply average or concatenate multiple sets of features extracted from different templates, which potentially ignores important structural information contained in the multi-template data. Accordingly, in this paper, we propose a novel relationship induced multi-template learning method for automatic diagnosis of Alzheimer’s disease (AD) and its prodromal stage, i.e., mild cognitive impairment (MCI), by explicitly modeling structural information in the multi-template data. Specifically, we first nonlinearly register each brain’s magnetic resonance (MR) image separately onto multiple pre-selected templates, and then extract multiple sets of features for this MR image. Next, we develop a novel feature selection algorithm by introducing two regularization terms to model the relationships among templates and among individual subjects. Using these selected features corresponding to multiple templates, we then construct multiple support vector machine (SVM) classifiers. Finally, an ensemble classification is used to combine outputs of all SVM classifiers, for achieving the final result. We evaluate our proposed method on 459 subjects from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database, including 97 AD patients, 128 normal controls (NC), 117 progressive MCI (pMCI) patients, and 117 stable MCI (sMCI) patients. The experimental results demonstrate promising classification performance, compared with several state-of-the-art methods for multi-template based AD/MCI classification.
SN 2014C: Shell structure and deceleration reveal details of ejecta colliding… with a dense circumstellar medium
Creators: name: Bietenholz, Michael
Publisher: name: Zenodo
Year: 2023

description: The unusual supernova 2014C, in the nearby galaxy NGC 7331, was initially of the H-poor Type Ib. Over the course of ~1 yr, however, it developed bright H-alpha lines, implying strong interaction with H-rich circumstellar medium (CSM). The expanding shock-front collided
 with a dense, H-rich shell of CSM at age of ~1 yr. Since then, the shock has emerged from the dense shell, and is now expanding into the lower density CSM beyond. I report on new VLBI measurements of SN 2014C made with the European VLBI Network ~5 yr after the explosion, as well as VLA and Chandra-NuSTAR X-ray observations. The VLBI observations, at 8.4 GHz, reveal a shell structure and continued expansion, with deceleration that appears to get stronger at the latest times. Since the first year after explosion, SN 2014C has shown an unusual, almost constant flux density as well as a relatively flat powerlaw spectrum. X-ray observations support the implications of the ejecta colliding with a dense CSM.
Dynamical Constraints on the Origin of Multiple Stellar Populations in Globular Clusters
Creators: name: Khalaj, Pouria
name: Baumgardt, Holger
Publisher: name: arXiv
Year: 2015
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We have carried out a large grid of N-body simulations in order to investigate if mass-loss as a result of primordial gas expulsion can be responsible for the large fraction of second generation stars in globular clusters (GCs) with multiple stellar populations (MSPs). Our clusters start with two stellar populations in which $10\%$ of all stars are second generation stars. We simulate clusters with different initial masses, different ratios of the half-mass radius of first to second generation stars, different primordial gas fractions and Galactic tidal fields with varying strength. We then let our clusters undergo primordial gas-loss and obtain their final properties such as mass, half-mass radius and the fraction of second generation stars. Using our N-body grid we then perform a Monte Carlo analysis to constrain the initial masses, radii and required gas expulsion time-scales of GCs with MSPs. Our results can explain the present-day properties of GCs only if (1) a substantial amount of gas was present in the clusters after the formation of second generation stars and (2) gas expulsion time-scales were extremely short ($\lesssim 10^5$ yr). Such short gas expulsion time-scales are in agreement with recent predictions that dark remnants have ejected the primordial gas from globular clusters, and pose a potential problem for the AGB scenario. In addition, our results predict a strong anti-correlation between the number ratio of second-generation stars in GCs and the present-day mass of GCs. So far, the observational data show only a significantly weaker anti-correlation, if any at all.
description: 14 pages, 6 figures, 3 tables, typos corrected. Accepted for publication in MNRAS
Sparse Multi-Response Tensor Regression for Alzheimer's Disease Study With Multivariate Clinical Assessments
Creators: name: Li, Lexin
name: Suk, Heung-Il
name: Shen, Dinggang
name: Li, Zhou
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disorder that has recently seen serious increase in the number of affected subjects. In the last decade, neuroimaging has been shown to be a useful tool to understand AD and its prodromal stage, amnestic mild cognitive impairment (MCI). The majority of AD/MCI studies have focused on disease diagnosis, by formulating the problem as classification with a binary outcome of AD/MCI or healthy controls. There have recently emerged studies that associate image scans with continuous clinical scores that are expected to contain richer information than a binary outcome. However, very few studies aim at modeling multiple clinical scores simultaneously, even though it is commonly conceived that multivariate outcomes provide correlated and complementary information about the disease pathology. In this article, we propose a sparse multi-response tensor regression method to model multiple outcomes jointly as well as to model multiple voxels of an image jointly. The proposed method is particularly useful to both infer clinical scores and thus disease diagnosis, and to identify brain subregions that are highly relevant to the disease outcomes. We conducted experiments on the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset, and showed that the proposed method enhances the performance and clearly outperforms the competing solutions.
TESS Experiments: Prosocial Motivation, Social Position, and Support for Social Welfare Policy
Creators: name: Wichowsky, Amber
Publisher: name: Roper Center for Public Opinion Research
Year: 2022

description: Time-sharing Experiments for the Social Sciences (TESS) offers researchers the opportunity to capture the internal validity of experiments. Investigators submit proposals, and TESS fields successful proposals for free on a representative sample of adults in the United States. This experiment was conducted to test the influence of perceived social position and prosocial messaging on Americans’ opinions about social welfare policies. Respondents were sorted by gender and then randomly assigned to one of three social comparison exercises (upward comparison, downward comparison, or no comparison/control). All respondents were asked to give their opinion of whether government is responsible for reducing income inequalities. Next, respondents in each of social comparison conditions were randomly assigned to answer either a unprimed or primed social policy opinion battery. Priming for social policy opinion questions presented a short description of an individual helped by the program. A total of 985 respondents participated. This allowed for comparison of attitudes about the welfare state across perceptions of relative social status and influence of induced prosocial motives, while accounting for heterogeneity of effects between genders.
Constraining jets from gravitational wave mergers with VLBI: challenges and opportunities
Creators: name: Gourdji, Kelly
Publisher: name: Zenodo
Year: 2023

description: Short gamma-ray bursts (SGRBs) offer an opportunity to study extreme examples of transient jets, providing insight into both the jet physics and the merger progenitors. While SGRBs have traditionally been seen only on-axis and at typically high redshift, the advent of gravitational-wave merger (GWM) detections means that much closer, off-axis events can also be identified and studied. The prototypical example of this new category was the landmark detection of the multiwavelength counterpart to binary neutron star merger GW170817, which provided an unprecedented view of an SGRB. In particular, its relative proximity enabled very long baseline interferometric (VLBI) observations that identified superluminal proper motion of the merger’s relativistic outflow, breaking the degeneracy between competing afterglow models and setting much tighter constraints on key jet parameters. However, VLBI data typically includes systematic sources of uncertainty that can be difficult to quantify, and will often be of low signal-to-noise for typical GWM jets. These two challenges complicate the estimation of jet parameters and especially the associated uncertainty. In this talk, I will discuss the main model-fitting challenges we face and present possible solutions toward more robust results.
Multimodal Fusion With Reference: Searching for Joint Neuromarkers of Working Memory Deficits in Schizophrenia
Creators: name: Mueller, Bryon A.
name: Bustillo, Juan
name: Belger, Aysenil
name: Potkin, Steven G.
name: Jiang, Tianzi
name: McEwen, Sarah
name: Mathalon, Daniel H.
name: Chen, Jiayu
name: Damaraju, Eswar
name: Turner, Jessica A.
name: Sui, Jing
name: Qi, Shile
name: Yu, Qingbao
name: Du, Yuhui
name: Van Erp, Theo G.M.
name: Ford, Judith M.
name: Calhoun, Vince D.
name: Yang, Jian
name: Voyvodic, James
name: Preda, Adrian
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2018

description: Multimodal fusion is an effective approach to take advantage of cross-information among multiple imaging data to better understand brain diseases. However, most current fusion approaches are blind, without adopting any prior information. To date, there is increasing interest to uncover the neurocognitive mapping of specific behavioral measurement on enriched brain imaging data; hence, a supervised, goal-directed model that enables a priori information as a reference to guide multimodal data fusion is in need and a natural option. Here we proposed a fusion with reference model, called “multi-site canonical correlation analysis with reference plus joint independent component analysis” (MCCAR+jICA), which can precisely identify co-varying multimodal imaging patterns closely related to reference information, such as cognitive scores. In a 3-way fusion simulation, the proposed method was compared with its alternatives on estimation accuracy of both target component decomposition and modality linkage detection. MCCAR+jICA outperforms others with higher precision. In human imaging data, working memory performance was utilized as a reference to investigate the covarying functional and structural brain patterns among 3 modalities and how they are impaired in schizophrenia. Two independent cohorts (294 and 83 subjects respectively) were used. Interestingly, similar brain maps were identified between the two cohorts, with substantial overlap in the executive control networks in fMRI, salience network in sMRI, and major white matter tracts in dMRI. These regions have been linked with working memory deficits in schizophrenia in multiple reports, while MCCAR+jICA further verified them in a repeatable, joint manner, demonstrating the potential of such results to identify potential neuromarkers for mental disorders.
Comparing Wigner, Husimi and Bohmian distributions: Which one is a true probability distribution in phase space?
Creators: name: Colomés, E.
name: Zhan, Z.
name: Oriols, X.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The Wigner distribution function is a quasi-probability distribution. When properly integrated, it provides the correct charge and current densities, but it gives negative probabilities in some points and regions of the phase space. Alternatively, the Husimi distribution function is positive-defined everywhere, but it does not provide the correct charge and current densities. The origin of all these difficulties is the attempt to construct a phase space within a quantum theory that does not allow well-defined (i.e. simultaneous) values of the position and momentum of an electron. In contrast, within the (de Broglie-Bohm) Bohmian theory of quantum mechanics, an electron has well-defined position and momentum. Therefore, such theory provides a natural definition of the phase space probability distribution and by construction, it is positive-defined and it exactly reproduces the charge and current densities. The Bohmian distribution function has many potentialities for quantum problems, in general, and for quantum transport, in particular, that remains unexplored.
description: 14 pages, 18 figures in Journal of Computational Electronics 2015
Dynamic response to transients with e-MERLIN
Creators: name: Williams, David
Publisher: name: Zenodo
Year: 2023

description: The e-MERLIN array is a set of 7 telescopes across England that form an interferometer capable of sub-arcsecond resolution and micro-Jansky sensitivity at centimetre wavelengths. It now regularly participates in the EVN, as well as having its own peer-reviewed science programme. In recent years, e-MERLIN has been used for a wide variety of science cases including to study AGNs, masers, galaxy clusters and transients, to name a handful. In order to improve access, the e-MERLIN operations team has improved data and processing channels through a new pipeline and has included a new "rapid response time" (RRT) mode to further enable transient studies. The rapid response time enables dynamic scheduling of transient sources to obtain early detections and positions of evolving radio sources.

 In this talk, I will give an overview of the preliminary transient science results that have come from the rapid response time data. This includes the 2021 outburst of the recurrent nova RS Oph, the long-lived radio jets from an X-ray binary in a young stellar cluster, rapid follow up observations of the brightest GRB of all time and a late-time radio detection of a type 1a supernova. I will discuss the need for rapid and dynamic scheduling capabalities offered by the RRT observations for VLBI science for the next decade. Finally, I will discuss further planned upgrades to e-MERLIN which will improve the impact of VLBI transient science long into the future.
Completing constrained flavor violation: lepton masses, neutrinos and leptogenesis
Creators: name: Cline, James M.
name: Diaz-Furlong, Alfonso
name: Ren, Jing
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Constrained flavor violation is a recent proposal for predicting the down-quark Yukawa matrix in terms of those for up quarks and charged leptons. We study the viability of CFV with respect to its predictions for the lepton mass ratios, showing that this remains a challenge, and suggest some possible means for improving this shortcoming. We then extend CFV to include neutrinos, and show that it leads to interesting predictions for hierachical heavy neutrinos, and leptogenesis dominated by decays of the second heaviest one ("N2 leptogenesis"), as well as the possibility of low-scale leptoquark-mediated exotic decays.
description: 13 pages, 7 figures; v.2: published version, reorganized and clarified leptogenesis section
Single- and Multiple-Shell Uniform Sampling Schemes for Diffusion MRI Using Spherical Codes
Creators: name: Cheng, Jian
name: Shen, Dinggang
name: Basser, Peter J.
name: Yap, Pew-Thian
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2018

description: In diffusion MRI (dMRI), a good sampling scheme is important for efficient acquisition and robust reconstruction. Diffusion weighted signal is normally acquired on single or multiple shells in q-space. Signal samples are typically distributed uniformly on different shells to make them invariant to the orientation of structures within tissue, or the laboratory coordinate frame. The Electrostatic Energy Minimization (EEM) method, originally proposed for single shell sampling scheme in dMRI, was recently generalized to multi-shell schemes, called Generalized EEM (GEEM). GEEM has been successfully used in the Human Connectome Project (HCP). However, EEM does not directly address the goal of optimal sampling, i.e., achieving large angular separation between sampling points. In this paper, we propose a more natural formulation, called Spherical Code (SC), to directly maximize the minimal angle between different samples in single or multiple shells. We consider not only continuous problems to design single or multiple shell sampling schemes, but also discrete problems to uniformly extract sub-sampled schemes from an existing single or multiple shell scheme, and to order samples in an existing scheme. We propose five algorithms to solve the above problems, including an incremental SC (ISC), a sophisticated greedy algorithm called Iterative Maximum Overlap Construction (IMOC), an 1-Opt greedy method, a Mixed Integer Linear Programming (MILP) method, and a Constrained Non-Linear Optimization (CNLO) method. To our knowledge, this is the first work to use the SC formulation for single or multiple shell sampling schemes in dMRI. Experimental results indicate that SC methods obtain larger angular separation and better rotational invariance than the state-of-the-art EEM and GEEM. The related codes and a tutorial have been released in DMRITool.
Feedback as a mechanism for the resurrection of oscillations from death state
Creators: name: Chandrasekar, V. K.
name: Karthiga, S.
name: Lakshmanan, M.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: The quenching of oscillations in interacting systems leads to several unwanted situations, which necessitate a suitable remedy to overcome the quenching. In this connection, this work addresses a mechanism that can resurrect oscillations in a typical situation. Through both numerical and analytical studies, we show the candidate which is capable of resurrecting oscillations is nothing but the feedback, the one which is profoundly used in dynamical control and in bio-therapies. Even in the case of a rather general system, we demonstrate analytically the applicability of the technique over one of the oscillation quenched states called amplitude death state. We also discuss some of the features of this mechanism such as adaptability of the technique with the feedback of only a few of the oscillators.
description: 15 pages, 15 figures
A Survey on Visual Analytics of Social Media Data
Creators: name: Wu, Yingcai
name: Gotz, David
name: Cao, Nan
name: Keim, Daniel A.
name: Tan, Yap-Peng
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: The unprecedented availability of social media data offers substantial opportunities for data owners, system operators, solution providers, and end users to explore and understand social dynamics. However, the exponential growth in the volume, velocity, and variability of social media data prevents people from fully utilizing such data. Visual analytics, which is an emerging research direction, ha...
A VLBI search for pulsars without pulsations
Creators: name: Atri, Pikky
Publisher: name: Zenodo
Year: 2023

description: The last few years have witnessed a surge in the discovery of exotic radio transients, expanding the realm of known transient classes owing to the increase in the sensitivity of radio surveys. Previous surveys revealed an excess of steep spectrum sources in the Galactic plane. The compact nature of these targets in the GMRT and the VLA surveys suggested that these were likely a new population of pulsars. However, unsuccessful detection of timing signatures from these targets led to the question: are all these steep spectrum sources extragalactic or are they an unexplored sub-population of pulsars without detectable pulsations? In this talk, I will give an overview of how we are using VLBI to determine if these confusing sources are indeed pulsars using a combination of measuring scatter-broadening in the image plane and proper motion using astrometry.
Correlated spinless fermions on the honeycomb lattice revisited
Creators: name: Scherer, Daniel D.
name: Scherer, Michael M.
name: Honerkamp, Carsten
Publisher: name: arXiv
Year: 2015
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate the quantum many-body instabilities of the extended Hubbard model for spinless fermions on the honeycomb lattice with repulsive nearest-neighbor and 2nd nearest-neighbor density-density interactions. Recent exact diagonalization and infinite density matrix renormalization group results suggest that a putative topological Mott insulator phase driven by the 2nd nearest-neighbor repulsion is suppressed, while other numerically exact approaches support the topological Mott insulator scenario. In the present work, we employ the functional renormalization group (fRG) for correlated fermionic systems. Our fRG results hint at a strong suppression of the scattering processes stabilizing the topological Mott insulator. From analyzing the effects of fermionic fluctuations, we obtain a phase diagram which is the result of the competition of various charge ordering instabilities.
description: 9 pages, 8 figures
Exemplar-AMMs: Recognizing Crowd Movements From Pedestrian Trajectories
Creators: name: Lau, Rynson W. H.
name: Liu, Wenxi
name: Manocha, Dinesh
name: Wang, Xiaogang
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: In this paper, we present a novel method to recognize the types of crowd movement from crowd trajectories using agent-based motion models (AMMs). Our idea is to apply a number of AMMs, referred to as exemplar-AMMs, to describe the crowd movement. Specifically, we propose an optimization framework that filters out the unknown noise in the crowd trajectories and measures their similarity to the exemplar-AMMs to produce a crowd motion feature. We then address our real-world crowd movement recognition problem as a multi-label classification problem. Our experiments show that the proposed feature outperforms the state-of-the-art methods in recognizing both simulated and real-world crowd movements from their trajectories. Finally, we have created a synthetic dataset, SynCrowd, which contains 2D crowd trajectories in various scenarios, generated by various crowd simulators. This dataset can serve as a training set or benchmark for crowd analysis work.
Single-Molecule Force Spectroscopy of Protein Folding
Creators: Petrosyan, Rafayel
Narayan, Abhishek
Woodside, Michael T
Publisher: name: University of Alberta Library
Year: 2021

The use of force probes to induce unfolding and refolding of single molecules through the application of mechanical tension, known as single-molecule force spectroscopy (SMFS), has proven to be a powerful tool for studying the dynamics of protein folding. Here we provide an overview of what has been learned about protein folding using SMFS, from small, single-domain proteins to large, multi-domain proteins. We highlight the ability of SMFS to measure the energy landscapes underlying folding, to map complex pathways for native and non-native folding, to probe the mechanisms of chaperones that assist with native folding, to elucidate the effects of the ribosome on co-translational folding, and to monitor the folding of membrane proteins.
Visuomotor Entrainment and the Frequency-Dependent Response of Walking Balance to Perturbations
Creators: name: Francis, Carrie A.
name: Thelen, Darryl G.
name: Franz, Jason R.
name: Allen, Matthew S.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2017

description: Visuomotor entrainment, or the synchronization of motor responses to visual stimuli, is a naturally emergent phenomenon in human standing. Our purpose was to investigate the prevalence and resolution of visuomotor entrainment in walking and the frequency-dependent response of walking balance to perturbations. We used a virtual reality environment to manipulate optical flow in ten healthy young adults during treadmill walking. A motion capture system recorded trunk, sacrum, and heel marker trajectories during a series of 3-min conditions in which we perturbed a virtual hallway mediolaterally with systematic changes in the driving frequencies of perceived motion. We quantified visuomotor entrainment using spectral analyses and changes in balance control using trunk sway, gait variability, and detrended fluctuation analyses (DFA). ML kinematics were highly sensitive to visual perturbations, and instinctively synchronized (i.e., entrained) to a broad range of driving frequencies of perceived ML motion. However, the influence of visual perturbations on metrics of walking balance was frequency-dependent and governed by their proximity to stride frequency. Specifically, we found that a driving frequency nearest to subjects' average stride frequency uniquely compromised trunk sway, gait variability, and step-to-step correlations. We conclude that visuomotor entrainment is a robust and naturally emerging phenomenon during human walking, involving coordinated and frequency-dependent adjustments in trunk sway and foot placement to maintain balance at the whole-body level. These findings provide mechanistic insight into how the visuomotor control of walking balance is disrupted by visual perturbations and important reference values for the emergence of balance deficits due to age, injury, or disease.
Learning Discriminative Bayesian Networks from High-Dimensional Continuous Neuroimaging Data
Creators: name: Zhou, Luping
name: Liu, Lingqiao
name: Ogunbona, Philip
name: Shen, Dinggang
name: Wang, Lei
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: Due to its causal semantics, Bayesian networks (BN) have been widely employed to discover the underlying data relationship in exploratory studies, such as brain research. Despite its success in modeling the probability distribution of variables, BN is naturally a generative model, which is not necessarily discriminative. This may cause the ignorance of subtle but critical network changes that are of investigation values across populations. In this paper, we propose to improve the discriminative power of BN models for continuous variables from two different perspectives. This brings two general discriminative learning frameworks for Gaussian Bayesian networks (GBN). In the first framework, we employ Fisher kernel to bridge the generative models of GBN and the discriminative classifiers of SVMs, and convert the GBN parameter learning to Fisher kernel learning via minimizing a generalization error bound of SVMs. In the second framework, we employ the max-margin criterion and build it directly upon GBN models to explicitly optimize the classification performance of the GBNs. The advantages and disadvantages of the two frameworks are discussed and experimentally compared. Both of them demonstrate strong power in learning discriminative parameters of GBNs for neuroimaging based brain network analysis, as well as maintaining reasonable representation capacity. The contributions of this paper also include a new Directed Acyclic Graph (DAG) constraint with theoretical guarantee to ensure the graph validity of GBN.
Parametric Regression on the Grassmannian
Creators: name: Singh, Nikhil
name: Kwitt, Roland
name: Hong, Yi
name: Niethammer, Marc
name: Vasconcelos, Nuno
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: Author(s): Hong, Y; Kwitt, R; Singh, N; Vasconcelos, N; Niethammer, M
title: Working Children as Social Subjects
title: The Contribution of Working Children's Organizations to Social Transformations
titleType: Subtitle
Creators: name: Liebel, Manfred
Publisher: name: Technische Universität Berlin
Year: 2003
Subjects: subject: 370 Bildung und Erziehung
subject: 150 Psychologie
subject: child labour
subject: child rights
subject: child work
subject: social movements
subject: working children

description: Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
description: This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
description: The article focuses on the question of what significance the organizations of working children, which have sprung up in various regions of the Third World since the 1980s, have for processes of transformation in their societies. First, it looks at the common ground shared by the working children and their organizations in different countries. Second, it discusses what kind of social subject emerges from this discussion. Finally, the article asks what possible effects these organizations have on the children themselves or on the society around them.
title: Χαρακτηρισμός πρόσδεσης μονοκλωνικών αντισωμάτων σε τομές εγκεφάλου επίμυος
title: Characterization of monoclonal antibody binding to mouse brain sections
titleType: AlternativeTitle
Creators: name: Τσένος, Ανδρέας Αλέξανδρος
Publisher: name: Πανεπιστήμιο Δυτικής Αττικής
Year: 2023
Subjects: Western blot
ELISA
mAbNR1
mAbNR2
mAbNR3
mAbNR4
mAbNR5
mAbNR6

description: Οι νικοτινικοί υποδοχείς ακετυλοχολίνης ανήκουν στην οικογένεια διαμεμβρανικών πρωτεϊνών που αλληλεπιδρούν με τον νευροδιαβιβαστή ακετυλοχολίνη και μεσολαβούν στη χολινεργική νευρομετάδοση. Επιπλέον, διαδραματίζουν σημαντικό ρόλο στη μάθηση, στη μνήμη, στην προσοχή και στον κινητικό έλεγχο. Ωστόσο, πολλές μελέτες έχουν δείξει ότι ο υποδοχέας α4β2 νικοτινικού υποδοχέα εμπλέκεται σε νευροπαθήσεις Myasthenia Gravis, Alzheimer, Parkinson, επιληψία και στην εξάρτηση από τη νικοτίνη. Τα μονοκλωνικά αντισώματα έναντι του α4β2 είναι πολύτιμα εργαλεία στην έρευνα του χολινεργικού συστήματος. O σκοπός της παρούσας μελέτης ήταν ο χαρακτηρισμός της πρόσδεσης των μονοκλωνικών αντισωμάτων (mAbNR1, mAbNR2, mAbNR3, mAbNR4, mAbNR5 και mABNR6) έναντι του α4β2 νικοτικού υποδοχέα ακετυλοχολίνης σε ιστούς εγκεφάλου επίμυος για τη διερεύνηση των ιδιοτήτων τους.
Rectangular layer model for profile-based human action recognition using multi-view depth information
Creators: name: Pongsagorn Chalearnnetkul
Publisher: name: Research and Technology Transfer Affairs Division.Khon Kaen University.
Year: 2017
Subjects: action recognition, multi-view, depth information, rectangular layer model

description: Asia-Pacific Journal of Science and Technology (APST), 22, 3, 1-6
Joint Calibration for Semantic Segmentation
Creators: name: Caesar, Holger
name: Uijlings, Jasper
name: Ferrari, Vittorio
Publisher: name: arXiv
Year: 2015
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences
subject: 68T45

description: Semantic segmentation is the task of assigning a class-label to each pixel in an image. We propose a region-based semantic segmentation framework which handles both full and weak supervision, and addresses three common problems: (1) Objects occur at multiple scales and therefore we should use regions at multiple scales. However, these regions are overlapping which creates conflicting class predictions at the pixel-level. (2) Class frequencies are highly imbalanced in realistic datasets. (3) Each pixel can only be assigned to a single class, which creates competition between classes. We address all three problems with a joint calibration method which optimizes a multi-class loss defined over the final pixel-level output labeling, as opposed to simply region classification. Our method outperforms the state-of-the-art on the popular SIFT Flow [18] dataset in both the fully and weakly supervised setting by a considerably margin (+6% and +10%, respectively).
description: Includes improved results based on VGG16 CNN
Roselle(Hibiscussabdariffa) calyce ethanolic extract decreases insulin resistance in high carbohydrate diet fed cats
Creators: name: Ranee Singh
Publisher: name: Research and Technology Transfer Affairs Division.Khon Kaen University.
Year: 2017
Subjects: Roselle
Triglyceride
Cholesterol
Blood glucose
Insulin resistance

description: Asia-Pacific Journal of Science and Technology (APST), 22, 4, 1-7
Design, Fabrication, and Characterization of a Bifrequency Colinear Array
Creators: name: Gallippi, Caterina M.
name: Wang, Zhuochen
name: Geng, Xuecang
name: Liu, Ruibin
name: Li, Sibo
name: Czernuszewicz, Tomasz J.
name: Jiang, Xiaoning
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: Ultrasound imaging with high resolution and large penetration depth has been increasingly adopted in medical diagnosis, surgery guidance, and treatment assessment. Conventional ultrasound works at a particular frequency, with a −6 dB fractional bandwidth of ~70 %, limiting the imaging resolution or depth of field. In this paper, a bi-frequency co-linear array with resonant frequencies of 8 MHz and 20 MHz was investigated to meet the requirements of resolution and penetration depth for a broad range of ultrasound imaging applications. Specifically, a 32-element bi-frequency co-linear array was designed and fabricated, followed by element characterization and real-time sectorial scan (S-scan) phantom imaging using a Verasonics system. The bi-frequency co-linear array was tested in four different modes by switching between low and high frequencies on transmit and receive. The four modes included the following: (1) transmit low, receive low, (2) transmit low, receive high, (3) transmit high, receive low, (4) transmit high, receive high. After testing, the axial and lateral resolutions of all modes were calculated and compared. The results of this study suggest that bi-frequency co-linear arrays are potential aids for wideband fundamental imaging and harmonic/sub-harmonic imaging.
A non-ideal approach to slurs
Creators: name: Mühlebach, Deborah
Publisher: name: Freie Universität Berlin
Year: 2023
Subjects: subject: Derogatory language use
subject: Semantics
subject: Pejoratives
subject: Swearwords
subject: Derogatory terms
subject: Inferentialism
subject: 100 Philosophie und Psychologie::100 Philosophie::102 Verschiedenes

description: Philosophers of language are increasingly engaging with derogatory terms or slurs. Only few theorists take such language as a starting point for addressing puzzles in philosophy of language with little connection to our real-world problems. This paper aims to show that the political nature of derogatory language use calls for non-ideal theorising as we find it in the work of feminist and critical race scholars. Most contemporary theories of slurs, so I argue, fall short on some desiderata associated with a non-ideal approach. They neglect crucial linguistic or political aspects of morally and politically significant meaning. I argue that a two-stage project is necessary to understand the perniciousness of slurs: accounting for the derogatory content of derogatory terms in general and, additionally, explaining the communicative function of slurs more specifically. I end by showing how inferentialism is well-suited to account for the content of derogatory terms whilst allowing for further explanations of the communicative functions of slurs.
Uncovering mnestic problems in help-seeking individuals reporting subjective cognitive complaints
Creators: name: Werrmann, Michelle
name: Schegolevska, Anna
name: Eid, Michael
name: Niedeggen, Michael
Publisher: name: Freie Universität Berlin
Year: 2023
Subjects: subject: Health care
subject: Psychology
subject: FOS: Psychology
subject: cognitive complaints
subject: 100 Philosophie und Psychologie::150 Psychologie::150 Psychologie

description: In individuals with subjective cognitive impairments (SCI) the risk for the development of a neurodegenerative disease is assumed to be increased. However, it is not clear which factors contribute to the expression of SCI: Is it related to the cognitive resources already challenged, or is the psycho-affective state of more relevance? Using a novel online assessment combining self-report questionnaires and neuropsychological psychometric tests, significant predictors for the level of complaints were identified in two samples of elderly individuals: Help-seekers (HS, n = 48) consulting a memory clinic and a matched sample of non-help-seekers (nHS, n = 48). Based on the results of the online assessment, the SCI level was found to be significantly determined by the psycho-affective state (depressive mood) in the nHS group, whereas cognitive performance (cued recall) was the main predictor in the HS group. The predictive value of recall performance, however, is more-strongly expressed in memory tests which reduce the impact of compensatory strategies (face–name-association vs. word lists). Our results indicate that the problem-focused behavior of help-seeking individuals is also associated with a higher sensitivity for cognitive deficits—which can be uncovered with an appropriate psychometric test. Considering these factors, the conversion risk in individuals with SCI can probably be determined more reliably.
On the Feasibility of Quantifying Fibrous Cap Thickness With Acoustic Radiation Force Impulse (ARFI) Ultrasound
Creators: name: Gallippi, Caterina M.
name: Czernuszewicz, Tomasz J.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: Acute cerebrovascular accidents are associated with the rupture of vulnerable atherosclerotic plaques in the carotid arteries. Fibrous cap thickness has been shown to be an important predictor of plaque rupture, but has been challenging to measure accurately with clinical noninvasive imaging modalities. The goals of this investigation were first, to evaluate the feasibility of using transcutaneous acoustic radiation force impulse (ARFI) ultrasound to quantify fibrous cap thickness and second, to optimize both imaging and motion tracking parameters to support such measurements. Fibrous caps with varying thickness (0.1 – 1.0 mm) were simulated using a simple layered geometry, and their mechanical response to an impulse of radiation force was solved using finite element method (FEM) modeling. Ultrasound tracking of FEM displacements was performed in Field II utilizing three center frequencies (6, 9, and 12 MHz) and eight motion tracking kernel lengths (0.5λ – 4λ). Additionally, fibrous cap thickness in two carotid plaques imaged in vivo was measured with ARFI and compared to matched histology. The results of this study demonstrate that 1) tracking pulse frequencies around 12 MHz are necessary to resolve caps around 0.2 mm, 2) large motion-tracking kernel sizes introduce bias into thickness measurements and overestimate the true cap thickness, and 3) color saturation settings on ARFI peak displacement images can impact thickness measurement accuracy substantially.
Terahertz Néel spin-orbit torques drive nonlinear magnon dynamics in antiferromagnetic Mn2Au
Creators: name: Behovits, Yannic
name: Chekhov, Alexander L.
name: Bodnar, S. Yu.
name: Gueckstock, Oliver
name: Reimers, S.
name: Lytvynenko, Y.
name: Skourski, Y.
name: Wolf, M.
name: Seifert, Tom S.
name: Kampfrath, Tobias
Publisher: name: Freie Universität Berlin
Year: 2023
Subjects: subject: Magnetic properties
subject: Magnetic materials
subject: Spintronics
subject: 500 Naturwissenschaften und Mathematik::530 Physik::530 Physik

description: Antiferromagnets have large potential for ultrafast coherent switching of magnetic order with minimum heat dissipation. In materials such as Mn2Au and CuMnAs, electric rather than magnetic fields may control antiferromagnetic order by Néel spin-orbit torques (NSOTs). However, these torques have not yet been observed on ultrafast time scales. Here, we excite Mn2Au thin films with phase-locked single-cycle terahertz electromagnetic pulses and monitor the spin response with femtosecond magneto-optic probes. We observe signals whose symmetry, dynamics, terahertz-field scaling and dependence on sample structure are fully consistent with a uniform in-plane antiferromagnetic magnon driven by field-like terahertz NSOTs with a torkance of (150 ± 50) cm2 A−1 s−1. At incident terahertz electric fields above 500 kV cm−1, we find pronounced nonlinear dynamics with massive Néel-vector deflections by as much as 30°. Our data are in excellent agreement with a micromagnetic model. It indicates that fully coherent Néel-vector switching by 90° within 1 ps is within close reach.
On the Quantitative Potential of Viscoelastic Response (VisR) Ultrasound Using the One-Dimensional Mass-Spring-Damper Model
Creators: name: Hossain, Md. Murad
name: Palmeri, Mark L.
name: Gallippi, Caterina M.
name: Moore, Christopher J.
name: Selzo, Mallory R.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016

description: Viscoelastic Response (VisR) ultrasound is an acoustic radiation force (ARF)-based imaging method that fits induced displacements to a one-dimensional (1D) mass-spring-damper (MSD) model to estimate the ratio of viscous to elastic moduli, τ, in viscoelastic materials. Error in VisR τ estimation arises from inertia and acoustic displacement underestimation. These error sources are herein evaluated using finite element method (FEM) simulations, error correction methods are developed, and corrected VisR τ estimates are compared to true simulated τ values to assess VisR’s relevance to quantifying viscoelasticity. In regards to inertia, adding a mass term in series with the Voigt model, to achieve the MSD model, accounts for inertia due to tissue mass when ideal point force excitations are used. However, when volumetric ARF excitations are applied, the induced complex system inertia is not described by the single-degree-of-freedom MSD model, causing VisR to overestimate τ. Regarding acoustic displacement underestimation, associated deformation of ARF-induced displacement profiles further distorts VisR τ estimates. However, median error in VisR τ is reduced to approximately −10% using empirically derived error correction functions applied to simulated viscoelastic materials with viscous and elastic properties representative of tissue. The feasibility of corrected VisR imaging is then demonstrated in vivo in the rectus femoris muscle of an adult with no known neuromuscular disorders. These results suggest VisR’s potential relevance to quantifying viscoelastic properties clinically.