cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Stochastic Thermodynamics Across Scales: Emergent Inter-attractoral Discrete Markov Jump Process and Its Underlying Continuous Diffusion
Creators: name: Santillan, Moises
name: Qian, Hong
Publisher: name: arXiv
Year: 2011
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Mathematical Physics (math-ph)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: The consistency across scales of a recently developed mathematical thermodynamic structure, between a continuous stochastic nonlinear dynamical system (diffusion process with Langevin or Fokker-Planck equations) and its emergent discrete, inter-attractoral Markov jump process, is investigated. We analyze how the system's thermodynamic state functions, e.g. free energy $F$, entropy $S$, entropy production $e_p$, and free energy dissipation $\dot{F}$, etc., are related when the continuous system is describe with a coarse-grained discrete variable. We show that the thermodynamics derived from the underlying detailed continuous dynamics is exact in the Helmholtz free-energy representation. That is, the system thermodynamic structure is the same as if one only takes a middle-road and starts with the "natural" discrete description, with the corresponding transition rates empirically determined. By "natural", we mean in the thermodynamic limit of large systems in which there is an inherent separation of time scales between inter- and intra-attractoral dynamics. This result generalizes a fundamental idea from chemistry and the theory of Kramers by including thermodynamics: while a mechanical description of a molecule is in terms of continuous bond lengths and angles, chemical reactions are phenomenologically described by the Law of Mass Action with rate constants, and a stochastic thermodynamics.
description: 21 pages, 1 figure
Visual discrimination and short-term memory for random patterns in patients with a focal cortical lesion
Creators: name: Greenlee, Mark W.
name: Koessler, M.
name: Cornelissen, F. W.
name: Mergner, T.
Publisher: name: Universität Regensburg
Year: 1997
Subjects: subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Visual discrimination and short-term recognition memory for computer-generated random patterns were explored in 23 patients with a postsurgical lesion in one of the cortical hemispheres. Their results are compared with those of 23 age-matched volunteers. In a same-different forced-choice discrimination task, d' and log beta (measures of sensitivity and bias), as well as reaction time (RT) were determined. All participants viewed patterns defined either by luminance contrast or isoluminant red-green color contrast, the amplitude of which was adjusted to be 10 times the respective detection threshold level. Block patterns consisting of a 6 x 6 matrix of light and dark (red and green) checks were randomly configured on each presentation. They were presented in pairs, randomly in two visual quadrants for a duration of 200 msec. Three presentation conditions were used: simultaneous presentation of reference and test stimulus, sequential presentation with a short delay (interstimulus interval, ISI = 3 s), and sequential presentation with a long delay (ISI = 6 s). The results indicate that patients with a lesion in the occipitotemporal cortex, the superior temporal cortex and the frontal cortex were significantly impaired on both luminance-contrast and color-contrast pattern discrimination. Patients with damage in the anterior inferotemporal cortex showed no overall impairment. The results suggest that performance in visual discrimination and recognition memory tasks rely on distributed neural processes with more than one neocortical location.
CoGeNT, DAMA, and Light Neutralino Dark Matter
Creators: name: Belikov, Alexander V.
name: Gunion, John F.
name: Hooper, Dan
name: Tait, Tim M. P.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Recent observations by the CoGeNT collaboration (as well as long standing observations by DAMA/LIBRA) suggest the presence of a $\sim 5$-10 GeV dark matter particle with a somewhat large elastic scattering cross section with nucleons ($σ\sim 10^{-40}$ cm$^2$).Within the context of the minimal supersymmetric standard model (MSSM), neutralinos in this mass range are not able to possess such large cross sections, and would be overproduced in the early universe. Simple extensions of the MSSM, however, can easily accommodate these observations. In particular, the extension of the MSSM by a chiral singlet superfield allows for the possibility that the dark matter is made up of a light singlino that interacts with nucleons largely through the exchange of a fairly light ($\sim$30-70 GeV) singlet-like scalar higgs, $\hi$. Such a scenario is consistent with all current collider constraints and can generate the signals reported by CoGeNT and DAMA/LIBRA. Furthermore, there is a generic limit of the extended model in which there is a singlet-like pseudoscalar higgs, $\ai$, with $\mai\sim \mhi$ and in which the $χ^0χ^0$ and $b\anti b, s\anti s$ coupling magnitudes of the $\hi$ and $\ai$ are very similar. In this case, the thermal relic abundance is automatically consistent with the measured density of dark matter if $\mchi$ is sufficiently small that $χ^0χ^0\to b\anti b$ is forbidden.
description: 6 pages, published version
Identifying transgene insertions in Caenorhabditis elegans genomes with Oxford Nanopore sequencing.
Creators: name: Millwood, Joshua D
name: Caldwell, Kim A
name: Sutton, John M
name: Caldwell, Guy A
name: Adams, Paula E
name: Thies, Jennifer L
name: Fierst, Janna L
Publisher: name: PeerJ
Year: 2024

description: Genetically modified organisms are commonly used in disease research and agriculture but the precise genomic alterations underlying transgenic mutations are often unknown. The position and characteristics of transgenes, including the number of independent insertions, influences the expression of both transgenic and wild-type sequences. We used long-read, Oxford Nanopore Technologies (ONT) to sequence and assemble two transgenic strains of Caenorhabditis elegans commonly used in the research of neurodegenerative diseases: BY250 (pPdat-1::GFP) and UA44 (GFP and human α-synuclein), a model for Parkinson's research. After scaffolding to the reference, the final assembled sequences were ∼102 Mb with N50s of 17.9 Mb and 18.0 Mb, respectively, and L90s of six contiguous sequences, representing chromosome-level assemblies. Each of the assembled sequences contained more than 99.2% of the Nematoda BUSCO genes found in the C. elegans reference and 99.5% of the annotated C. elegans reference protein-coding genes. We identified the locations of the transgene insertions and confirmed that all transgene sequences were inserted in intergenic regions, leaving the organismal gene content intact. The transgenic C. elegans genomes presented here will be a valuable resource for Parkinson's research as well as other neurodegenerative diseases. Our work demonstrates that long-read sequencing is a fast, cost-effective way to assemble genome sequences and characterize mutant lines and strains.
OLEDs as models for bird magnetoception: detecting electron spin resonance in geomagnetic fields
Creators: name: Grünbaum, Tobias
name: Milster, Sebastian
name: Kraus, Hermann
name: Ratzke, Wolfram
name: Kurrmann, Simon
name: Zeller, Viola
name: Bange, Sebastian
name: Boehme, Christoph
name: Lupton, John M.
Publisher: name: Universität Regensburg
Year: 2019
Subjects: subject: 530 Physik

description: Certain species of living creatures are known to orientate themselves in the geomagnetic field. Given the small magnitude of approximately 48 µT, the underlying quantum mechanical phenomena are expected to exhibit coherence times in the microsecond regime. In this contribution, we show the sensitivity of organic light-emitting diodes (OLEDs) to magnetic fields far below Earth’s magnetic field, suggesting that coherence times of the spins of charge-carrier pairs in these devices can be similarly long. By electron paramagnetic resonance (EPR) experiments, a lower bound for the coherence time can be assessed directly. Moreover, this technique offers the possibility to determine the distribution of hyperfine fields within the organic semiconductor layer. We extend this technique to a material system exhibiting both fluorescence and phosphorescence, demonstrating stable anticorrelation between optically detected magnetic resonance (ODMR) spectra in the singlet (fluorescence) and triplet (phosphorescence) channels. The experiments demonstrate the extreme sensitivity of OLEDs to both static as well as dynamic magnetic fields and suggest that coherent spin precession processes of coulombically bound electron-spin pairs may play a crucial role in the magnetoreceptive ability of living creatures.
Time course of contrast adaptation to VDU-displayed text
Creators: name: Magnussen, Svein
name: Dyrnes, Stein
name: Greenlee, Mark W.
name: Nordby, Knut
name: Watten, Reidulf G.
Publisher: name: Universität Regensburg
Year: 1992
Subjects: subject: VDU, text editing, contrast adaptation, recovery
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: VDU text-editing induces contrast adaptation at the predominant spatial frequencies (periodicity) of the text page. Visual contrast sensitivity was tested after 10 and 60 min reading of VDU-displayed text of positive and negative contrast polarity. Contrast sensitivity impairments in-the order of 0-4 to 0-7 log unit change in contrast thresholds were observed. This contrast threshold elevation after-effect decays as a power function of time, with time required to recover from adaptation approximately corresponding to the reading times. At low spatial frequencies (horizontal periodicity of rows), displays of negative polarity induce stronger contrast adaptation than displays of positive polarity, at medium spatial frequencies (vertical periodicity of characters) no effect of contrast polarity was observed. The results are discussed in relation to VDU-induced visual fatique.
URSA: A System for Uniform Reduction to SAT
Creators: name: Janicic, Predrag
Publisher: name: arXiv
Year: 2010
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences
subject: F.4.1, D.3.2

description: There are a huge number of problems, from various areas, being solved by reducing them to SAT. However, for many applications, translation into SAT is performed by specialized, problem-specific tools. In this paper we describe a new system for uniform solving of a wide class of problems by reducing them to SAT. The system uses a new specification language URSA that combines imperative and declarative programming paradigms. The reduction to SAT is defined precisely by the semantics of the specification language. The domain of the approach is wide (e.g., many NP-complete problems can be simply specified and then solved by the system) and there are problems easily solvable by the proposed system, while they can be hardly solved by using other programming languages or constraint programming systems. So, the system can be seen not only as a tool for solving problems by reducing them to SAT, but also as a general-purpose constraint solving system (for finite domains). In this paper, we also describe an open-source implementation of the described approach. The performed experiments suggest that the system is competitive to state-of-the-art related modelling systems.
description: 39 pages, uses tikz.sty
Measuring Gravitational Lensing Flexions in Abell 1689 Using an Analytic Image Model
Creators: name: Cain, Benjamin
name: Schechter, Paul L.
name: Bautz, M. W.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Measuring dark matter substructure within galaxy cluster haloes is a fundamental probe of the Lambda-CDM model of structure formation. Gravitational lensing is a technique for measuring the total mass distribution which is independent of the nature of the gravitating matter, making it a vital tool for studying these dark-matter dominated objects. We present a new method for measuring weak gravitational lensing flexions, the gradients of the lensing shear field, to measure mass distributions on small angular scales. While previously published methods for measuring flexions focus on measuring derived properties of the lensed images, such as shapelet coefficients or surface brightness moments, our method instead fits a mass-sheet-transformation-invariant Analytic Image Model (AIM) to the each galaxy image. This simple parametric model traces the distortion of lensed image isophotes and constrains the flexion fields. We test the AIM method using simulated data images with realistic noise and a variety of unlensed image properties, and show that it successfully reproduces the input flexion fields. We also apply the AIM method for flexion measurement to Hubble Space Telescope observations of Abell 1689, and detect mass structure in the cluster using flexions measured with the AIM method.
description: 44 pages, 4 figures, 3 tables. Accepted to ApJ. V2 (published version) has minor changes from V1; ApJ 736 (2011)
TTS-Transducer: End-to-End Speech Synthesis with Neural Transducer
Creators: name: Bataev, Vladimir
name: Ghosh, Subhankar
name: Lavrukhin, Vitaly
name: Li, Jason
Publisher: name: arXiv
Year: 2025
Subjects: subject: Audio and Speech Processing (eess.AS)
subject: Artificial Intelligence (cs.AI)
subject: Computation and Language (cs.CL)
subject: Sound (cs.SD)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: This work introduces TTS-Transducer - a novel architecture for text-to-speech, leveraging the strengths of audio codec models and neural transducers. Transducers, renowned for their superior quality and robustness in speech recognition, are employed to learn monotonic alignments and allow for avoiding using explicit duration predictors. Neural audio codecs efficiently compress audio into discrete codes, revealing the possibility of applying text modeling approaches to speech generation. However, the complexity of predicting multiple tokens per frame from several codebooks, as necessitated by audio codec models with residual quantizers, poses a significant challenge. The proposed system first uses a transducer architecture to learn monotonic alignments between tokenized text and speech codec tokens for the first codebook. Next, a non-autoregressive Transformer predicts the remaining codes using the alignment extracted from transducer loss. The proposed system is trained end-to-end. We show that TTS-Transducer is a competitive and robust alternative to contemporary TTS systems.
description: Accepted by ICASSP 2025
Probe the universe with PIXIE experiment and tSZ-lensing cross-correlation
Creators: name: Yan, Ziang
Publisher: name: University of British Columbia
Year: 2017

description: The polarization of Cosmic Microwave Background can help us probe the early universe. The polarization pattern can be classified into E-mode and B- mode. The B-mode polarization is a smoking gun of cosmological inflation. PIXIE is an in-proposal space telescope observing CMB polarization. It is extremely powerful to extract CMB polarization signal from foreground contamination. The second chapter of this thesis summarizes my work on optimizing the optical system of PIXIE. I run a Monte-Carlo Markov Chain for the instrument parameters to maximize the value ”Good” which judges the behavior of the instrument. For the optimized instrument, with all kinds of noises from inside instrument and wrong polarization taken into account, good rays from the sky make up of 15.27% of all the rays received by the detector. The instrument has a 1.1° top-hat beam response. The third chapter summarizes my work on studying the potential con- tamination in the reconstructed y map by doing cross-correlation between tSZ signal and weak lensing. The weak lensing data is the convergence map from the Red Sequence Cluster Lensing Survey. I reconstruct the tSZ map with a Needlet Internal Linear Combination method with 6 HFI sky maps made by Planck satellite. The reconstructed cross correlation is consistent with Planck NILC SZ map. I take Cosmic Infrared Background (CIB) and galactic dust as two potential source of contamination in the reconstructed map. I find that κ × CIB contributes (5.8 ± 4.6)% in my reconstructed NILC y map for 500 < l < 2000 with 2.2σ significance. Dust residuals only change the error bar of the cross correlation signal. I find the best value for dust index is β_d = 1.57. I then introduce a piecewise power spectrum for the CIB and make a NILC CIB map to make a CIB-nulled NILC y map. κ × y signal from this y map differs by only ~0.08σ to the CIB-uncleaned y map.
Convergence of the parabolic complex Monge-Ampère equation on compact Hermitian manifolds
Creators: name: Gill, Matt
Publisher: name: arXiv
Year: 2010
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: We prove $C^\infty$ convergence for suitably normalized solutions of the parabolic complex Monge-Ampère equation on compact Hermitian manifolds. This provides a parabolic proof of a recent result of Tosatti and Weinkove.
description: 21 pages, some minor corrections, to appear in Comm. Anal. Geom
Contrast detection, discrimination and adaptation in patients with Parkinson's disease and multiple system atrophy
Creators: name: Tebartz van Elst, L.
name: Greenlee, Mark W.
name: Foley, John M.
name: Luecking, Carl H.
Publisher: name: Universität Regensburg
Year: 1997
Subjects: subject: contrast discrimination; adaptation; Parkinson’s disease; multiple system atrophy; neurodegenerative diseases
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Visual spatial contrast thresholds and suprathreshold contrast matches were measured before and after adaptation to high-contrast sinewave gratings in patients with Parkinson's disease (n = 27), patients with multiple system atrophy (n = 6) and a group of age-matched control patients without CNS disease (n = 27). Contrast thresholds were higher in the Parkinson's disease patients than in either the multiple system atrophy patients or control patients. The effect of contrast adaptation on both contrast thresholds and matches was approximately equal in the three groups. This suggests that contrast adaptation is not affected by these CNS disorders and is consistent with the hypothesis that the loss in contrast sensitivity in Parkinson's disease is mediated by retinal effects. The results are discussed in terms of the underlying pathology of the visual deficits in Parkinson's disease and the possible diagnostic implications for differentiating Parkinson's disease and multiple system atrophy.
fMRI Response During Visual Motion Stimulation in Patients with Late Whiplash Syndrome
Creators: name: Freitag, P.
name: Greenlee, Mark W.
name: Wachter, K.
name: Ettlin, Th. M.
name: Radue, E. W.
Publisher: name: Universität Regensburg
Year: 2001
Subjects: subject: Whiplash, fMRI, Visual motion perception
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: After whiplash trauma, up to one fourth of patients develop chronic symptoms including head and neck pain and cognitive disturbances. Resting perfusion single-pho ton-emission computed tomography (SPECT) found decreased temporoparietooccipi tal tracer uptake among these long-term symptomatic patients with late whiplash syn drome. As MT/MST (V5/V5a) are located in that area, this study addressed the question whether these patients show impairments in visual motion perception. We examined five symptomatic patients with late whiplash syndrome, five asymptomatic patients after whiplash trauma, and a control group of seven volunteers without the history of trauma. Tests for visual motion perception and functional magnetic resonance imaging (fMRI) measurements during visual motion stimulation were performed. Symptomatic patients showed a significant reduction in their ability to perceive coherent visual motion com pared with controls, whereas the asymptomatic patients did not show this effect. fMRI activation was similar during random dot motion in all three groups, but was signifi cantly decreased during coherent dot motion in the symptomatic patients compared with the other two groups. Reduced psychophysical motion performance and reduced fMRI responses in symptomatic patients with late whiplash syndrome both point to a functional impairment in cortical areas sensitive to coherent motion. Larger studies are needed to confirm these clinical and functional imaging results to provide a possible additional diagnostic criterion for the evaluation of patients with late whiplash syndrome.
TGIU Framework  Teoria-Gravito-Informationala Universală/Universal Gravitational Informational Theory
Creators: name: Virtosu, Sebastian
Publisher: name: Zenodo
Year: 2025

description: Non numerical and non metrical information is the source of collapse/Big Bang which generated motion, time, 3D space, matter-energy, mass, entropy. This information is from a domain, called 2D, because has two non spatial dimensions: information and infinite potential energy. The informational part is made from symmetrical and asymmetrical fractals. Asymmetrical fractals generate a collapse through 1D potential gravity which generates motion, time, space, matter-energy, mass.
Brain activation during dichoptic presentation of optic flow stimuli
Creators: name: Rutschmann, Roland M.
name: Schrauf, Michael
name: Greenlee, Mark W.
Publisher: name: Universität Regensburg
Year: 2000
Subjects: subject: Functional magnetic resonance imaging, Optic flow, Visual cortex, Disparity, Stereo vision
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: The processing of optic flow fields in motion-sensitive areas in human visual cortex was studied with BOLD (blood oxygen level dependent) contrast in functional magnetic resonance imaging (fMRI). Subjects binocularly viewed optic flow fields in plane (monoptic) or in stereo depth (dichoptic) with various degrees of disparity and increasing radial speed. By varying the directional properties of the stimuli (expansion, spiral motion, random), we explored whether the BOLD effect reflected neuronal responses to these different forms of optic flow. The results suggest that BOLD contrast as assessed by fMRI methods reflects the neural processing of optic flow information in motion-sensitive cortical areas. Furthermore, small but replicable disparity-selective responses were found in parts of Brodmann's area 19.
COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses IX. Time delays, lens dynamics and baryonic fraction in HE 0435-1223
Creators: name: Courbin, F.
name: Chantry, V.
name: Revaz, Y.
name: Sluse, D.
name: Faure, C.
name: Tewes, M.
name: Eulaers, E.
name: Koleva, M.
name: Asfandiyarov, I.
name: Dye, S.
name: Magain, P.
name: van Winckel, H.
name: Coles, J.
name: Saha, P.
name: Ibrahimov, M.
name: Meylan, G.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present accurate time delays for the quadruply imaged quasar HE 0435-1223. The delays were measured from 575 independent photometric points obtained in the R-band between January 2004 and March 2010. With seven years of data, we clearly show that quasar image A is affected by strong microlensing variations and that the time delays are best expressed relative to quasar image B. We measured Delta_t(BC) = 7.8+/-0.8 days, Delta_t(BD) = -6.5+/-0.7 days and Delta_t_CD = -14.3+/-0.8 days. We spacially deconvolved HST NICMOS2 F160W images to derive accurate astrometry of the quasar images and to infer the light profile of the lensing galaxy. We combined these images with a stellar population fitting of a deep VLT spectrum of the lensing galaxy to estimate the baryonic fraction, $f_b$, in the Einstein radius. We measured f_b = 0.65+0.13-0.10 if the lensing galaxy has a Salpeter IMF and f_b = 0.45+0.04-0.07 if it has a Kroupa IMF. The spectrum also allowed us to estimate the velocity dispersion of the lensing galaxy, sigma_ap = 222+/-34 km/s. We used f_b and sigma_ap to constrain an analytical model of the lensing galaxy composed of an Hernquist plus generalized NFW profile. We solve the Jeans equations numerically for the model and explored the parameter space under the additional requirement that the model must predict the correct astrometry for the quasar images. Given the current error bars on f_b and sigma_ap, we did not constrain H0 yet with high accuracy, i.e., we found a broad range of models with chi^2 < 1. However, narrowing this range is possible, provided a better velocity dispersion measurement becomes available. In addition, increasing the depth of the current HST imaging data of HE 0435-1223 will allow us to combine our constraints with lens reconstruction techniques that make use of the full Einstein ring that is visible in this object.
description: 12 pages, 10 figures, final version accepted for publication by A&A
The targum (1975:Feb. 3 - 1975:Feb 28)
Creators: name: No Name Supplied
Publisher: name: Targum Association
Year: 1975

description: Some University historians indicate that the Targum was first published as an annual in 1867, but of this we have no extant evidence. In January 1869, the Targum as we now know it, made its appearance as a monthly paper that concerned itself with student “literary contributions” and college news as well as serving as a vehicle for bringing news to alumni and the general public. The newspaper, which originally was for sale, varied in frequency over the years as did its title (The Targum, Rutgers Targum, Rutgers Daily Targum, and Daily Targum). The newspaper has continuously been published since 1869 with the exception of 19 months during the second world war, between February 1944 and October 1945. The Targum was published by the students of Rutgers College, and later Rutgers University—New Brunswick represented through the years as the Targum Association, Rutgers Targum Association, and Rutgers College Targum. As a student organization, the Targum operated under the oversight of the dean of students and student government but in October 1980, the Targum became an independent college paper.
Strong quantum interference in strongly disordered bosonic insulators
Creators: name: Syzranov, S. V.
name: Moor, A.
name: Efetov, K. B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We study the variable-range hopping (VRH) of bosons in an array of sites with short-range interactions and a large characteristic coordination number. The latter leads to strong quantum interference phenomena yet allows for their analytical study. We develop a functional renormalization group scheme that repeatedly eliminates high-energy sites properly renormalizing the tunnelling between the low-energy ones. Using this approach we determine the temperature and magnetic field dependence of the hopping conductivity and find a large positive magnetoresistance. With increasing magnetic field the behaviour of the conductivity crossovers from the Mott's law to an activational behaviour with the activation gap proportional to the magnetic field.
description: 4+ pages, 2 figures
Visual search and visual working memory in patients with chronic focal cortical lesions
Creators: name: Greenlee, Mark W.
name: Berg, Helga
name: Stuhr, Volker
name: Mergner, Thomas
Publisher: name: Universität Regensburg
Year: 2000
Subjects: subject: Working memory, Visual search, Eye movements, Brain lesions
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Visually guided behavior is known to involve temporo-parietal, inferotemporal, and prefrontal cortex and each of these areas appears to contribute to visual working memory. We explored the extent to which chronic lesions in one of these cortical areas affect visually guided oculomotor performance. We also explore whether possible impairments become more pronounced with increasing memory load. With this aim we recorded saccadic eye movements in 19 patients with a chronic focal postsurgical lesion in either temporo-parietal, inferior temporal or prefrontal cortex. Their results are compared to those of 19 age-matched volunteers. The subjects performed three different visual search tasks with increasing memory load: Instructed search, cue-guided search and memory-guided search. In addition, the latter task was performed with a short (1 s) and a long (6 s) delay. All tasks required the subjects to make a saccade to a single target presented together with one or three distractors. The results indicate that patients with inferotemporal lesions make the most task-related errors. Saccadic reaction times (SRTs) were significantly prolonged in patients with temporo-parietal and prefrontal lesions, but were unaffected in the patients with lesions in the inferotemporal cortex. The spatial accuracy of saccades was lowest in patients with temporo-parietal lesions. An increase in memory load led to more errors, to longer reaction times and to lower saccadic precision. However, the effect was similar across the three patient groups and the controls. An error analysis indicated that both patients and controls tended to weight global (luminance contrast and form) features higher than local features (line-segment orientation) when making difficult perceptual decisions.
B6.1 Enabling Family Engagement to Support Literacy, Digital Literacy, and Numeracy Development for All Children
Creators: name: Nic Mhuirí, Siún
name: Farrell, Thérèse
name: French, Geraldine
name: McCormack, Marlene
name: Shiel, Caoimhe
Publisher: name: Zenodo
Year: 2022
Subjects: Family Engagement, Literacy, Digital Literacy, Numeracy

description: B6.1
Electrophysiological localization of brain regions involved in perceptual memory
Creators: name: Reinvang, Ivar
name: Magnussen, S.
name: Greenlee, Mark W.
name: Larsson, Paal G.
Publisher: name: Universität Regensburg
Year: 1998
Subjects: subject: Event-related potentials, Memory, Spatial frequency, Human
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Event-related potentials (ERP) were recorded during perceptual discrimination and short-term memory, varying the interstimulus interval (1–10 s) in delayed spatial frequency discrimination. Accuracy of discrimination remained unimpaired across this time interval, but choice reaction times increased. A brain source localization (BESA) model showed that the activity of the parietal and right temporal sources increased with long retention intervals in a sequential activation pattern where a long-latency component of the parietal source specific to the memory condition was observed, the latency of which matched a memory-related increase in choice reaction times in the cognitive task. It is suggested that the temporal sources are involved in encoding and storage of visual information, and the parietal source is involved in memory retrieval.
Relationship between saccadic eye movements and cortical activity as measured by fMRI: quantitative and qualitative aspects
Creators: name: Kimmig, H.
name: Greenlee, M.
name: Gondan, M.
name: Schira, M.
name: Kassubek, J.
name: Mergner, T.
Publisher: name: Universität Regensburg
Year: 2001
Subjects: subject: Functional brain imaging, BOLD effect, Saccades, Eye movement recordings, Antisaccades
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: We investigated the quantitative relationship between saccadic activity (as reflected in frequency of occurrence and amplitude of saccades) and blood oxygenation level dependent (BOLD) changes in the cerebral cortex using functional magnetic resonance imaging (fMRI). Furthermore, we investigated quantitative changes in cortical activity associated with qualitative changes in the saccade task for comparable levels of saccadic activity. All experiments required the simultaneous acquisition of eye movement and fMRI data. For this purpose we used a new high-resolution limbus-tracking technique for recording eye movements in the magnetic resonance tomograph. In the first two experimental series we varied both frequency and amplitude of saccade stimuli (target jumps). In the third series we varied task difficulty; subjects performed either pro-saccades or anti-saccades. The brain volume investigated comprised the frontal and supplementary eye fields, parietal as well as striate cortex, and the motion sensitive area of the parieto-occipital cortex. All these regions showed saccade-related BOLD responses. The responses in these regions were highly correlated with saccade frequency, indicating that repeated processing of saccades is integrated over time in the BOLD response. In contrast, there was no comparable BOLD change with variation of saccade amplitude. This finding speaks for a topological rather than activity-dependent coding of saccade amplitudes in most cortical regions. In the experiments comparing pro- vs anti-saccades we found higher BOLD activation in the "anti" task than in the "pro" task. A comparison of saccade parameters revealed that saccade frequency and cumulative amplitude were comparable between the two tasks, whereas reaction times were longer in the "anti" task than the pro task. The latter finding is taken to indicate a more demanding cortical processing in the "anti" task than the "pro" task, which could explain the observed difference in BOLD activation. We hold that a quantitative analysis of saccade parameters (especially saccade frequency and latency) is important for the interpretation of the BOLD changes observed with visual stimuli in fMRI.
The large scale structure of complete $4$-manifolds with nonnegative Ricci curvature and Euclidean volume growth
Creators: name: Semola, Daniele
Publisher: name: arXiv
Year: 2025
Subjects: subject: Differential Geometry (math.DG)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 53C23

description: We survey the implications of our joint work with E. Bruè and A. Pigati on the structure of blow-downs for a smooth, complete, Riemannian $4$-manifold with nonnegative Ricci curvature and Euclidean volume growth. Very imprecisely, any such manifold looks like a cone over a spherical space form at infinity. We present some open questions and discuss possible future directions along the way.
description: Comments are welcome!
Nucleon Spin-Polarisabilities from Polarisation Observables in Low-Energy Deuteron Compton Scattering
Creators: name: Griesshammer, Harald W.
name: Shukla, Deepshikha
Publisher: name: arXiv
Year: 2010
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We investigate the dependence of polarisation observables in elastic deuteron Compton scattering below the pion production threshold on the spin-independent and spin-dependent iso-scalar dipole polarisabilities of the nucleon. The calculation uses Chiral Effective Field Theory with dynamical Delta(1232) degrees of freedom in the Small Scale Expansion at next-to-leading order. Resummation of the NN intermediate rescattering states and including the Delta induces sizeable effects. The analysis considers cross-sections and the analysing power of linearly polarised photons on an unpolarised target, and cross-section differences and asymmetries of linearly and circularly polarised beams on a vector-polarised deuteron. An intuitive argument helps one to identify kinematics in which one or several polarisabilities do not contribute. Some double-polarised observables are only sensitive to linear combinations of two of the spin-polarisabilities, simplifying a multipole-analysis of the data. Spin-polarisabilities can be extracted at photon energies \gtrsim 100 MeV, after measurements at lower energies of \lesssim 70 MeV provide high-accuracy determinations of the spin-independent ones. An interactive Mathematica 7.0 notebook of our findings is available from hgrie@gwu.edu.
description: 30 pages LaTeX2e, including 22 figures as 66 .eps file embedded with includegraphicx; three errors in initial submission corrected. This submission includes ot the erratum to be published in EPJA (2012) and the corrections in the text
Similarities and dissimilarities between pattern VEPs and motion VEPs
Creators: name: Göpfert, Edith
name: Müller, Rolf
name: Breuer, David
name: Greenlee, Mark W.
Publisher: name: Universität Regensburg
Year: 1998
Subjects: subject: adaptation, contrast dependence, motion VEP, N200 wave, pattern VEP, P100 wave
subject: 150 Psychologie

description: The contrast response functions (CRF) of pattern-appearance and motion-onset VEPs for periodic stimuli (gratings) were compared. The CRF for pattern-appearance is accelerative for the P100 component and compressive for the N200 component. Contrary to these results, the CRF for motion-onset shows an almost negligible slope for both components within the contrast range tested (0.5–64%). To better isolate the neural contributions to these different VEP components, we studied the effects of prior adaptation to stationary and moving gratings. Adaptation to stationary gratings has no effect on both VEP components for motion-onset and the P100 component for pattern-appearance, but did reduce the amplitude of the N200 for pattern-appearance. Adaptation to slow (1 deg/s) and fast (4 deg/s) gratings left the P100 amplitudes unaltered, while it significantly reduced the N200 amplitudes for both pattern-appearance and motion-onset. These results suggest that the N200 component of the motion-onset VEP is generated by motion-dependent neurons, whereas the same component for pattern-appearance arises from contrast-dependent neurons. The observed differences between P100 and N200 components appear to reflect the activity of both transient and sustained neural mechanisms
B6.2 Enabling Community Engagement to Support Literacy, Digital Literacy, and Numeracy Development for All Children
Creators: name: French, Geraldine
name: Farrell, Thérèse
name: McCormack, Marlene
name: Nic Mhuirí, Siún
name: Shiel, Caoimhe
Publisher: name: Zenodo
Year: 2022
Subjects: Community Engagement, Literacy, Digital Literacy, Numeracy

description: B6.2
Finding a record in a database
Creators: name: Fatemi, Bahare
Publisher: name: University of British Columbia
Year: 2017

description: Consider the following problem: given a database of records indexed by names (e.g., of companies or restaurants) and a new name, determine whether the new name is in the database, and if so, which record it refers to. This problem is called record linkage. Record linkage is a challenging problem because people do not consistently use the official title of a company, but use abbreviations, synonyms, different orders of terms, and the title can contain typos. We provide a probabilistic model using relational logistic regression to find the probability of each record in the database being the desired record for a given query, and find the best record(s). Our model addresses many of challenges of the record linkage problem and provides good results when exact term matching search algorithms fail. We evaluate our model on a large real-world data set. Obtained results show that the model is a promising probabilistic record linkage model.
Estimating Receptive Field Size from fMRI Data in Human Striate and Extrastriate Visual Cortex
Creators: name: Smith, A. T.
name: Singh, K. D.
name: Williams, A. L.
name: Greenlee, Mark W.
Publisher: name: Universität Regensburg
Year: 2001
Subjects: subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Functional magnetic resonance imaging (fMRI) was used to estimate the average receptive field sizes of neurons in each of several striate and extrastriate visual areas of the human cerebral cortex. The boundaries of the visual areas were determined by retinotopic mapping procedures and were visualized on flattened representations of the occipital cortex. Estimates of receptive field size were derived from the temporal duration of the functional activation at each cortical location as a visual stimulus passed through the receptive fields represented at that location. Receptive fields are smallest in the primary visual cortex (V1). They are larger in V2, larger again in V3/VP and largest of all in areas V3A and V4. In all these areas, receptive fields increase in size with increasing stimulus eccentricity. The results are qualitatively in line with those obtained by others in macaque monkeys using neurophysiological methods.
Visual contrast response functions in Parkinson's disease: evidence from electroretinograms, visually evoked potentials and psychophysics
Creators: name: Langheinrich, T.
name: Tebartz van Elst, L.
name: Lagrèze, W. A.
name: Bach, M.
name: Lücking, C. H.
name: Greenlee, Mark W.
Publisher: name: Universität Regensburg
Year: 2000
Subjects: subject: Contrast discrimination, Electroretinogram, Visual evoked potentials, Parkinson's disease, Neurodegenerative diseases
subject: 570 Biowissenschaften, Biologie

description: Objectives: Visual contrast detection thresholds and suprathreshold contrast discrimination thresholds were compared to luminance and flash/pattern electroretinograms (ERG) and visually evoked potentials (VEP) in patients with Parkinson's disease (n=31), patients with multiple system atrophy (n=6), patients with progressive supranuclear palsy (n=6) and control patients without central nervous disease (n=33). Methods: The stimuli were luminance modulated full-field (flash) or horizontally oriented sinewave gratings (pattern), the latter having either a low (0.5 cycles/deg) or medium (4.0 cycles/deg) spatial frequency. Stimulus contrast ranged from 10 to 80% so that contrast response functions could be derived. Results: Contrast thresholds were higher in the patients with Parkinson's disease than in the control patients. Contrast discrimination thresholds were also somewhat elevated in patients with Parkinson's disease. Pattern ERG amplitudes were significantly reduced in patients with Parkinson's disease for the medium spatial frequency stimulus, but less for the low spatial frequency and flash stimuli. Conclusions: Our results suggest that Parkinson’s disease impairs contrast processing in the retina. VEP amplitudes did not significantly differ between the groups for the conditions tested. Patients with progressive supranuclear palsy also showed impaired contrast perception and reduced ERG amplitudes, whereas patients with multiple system atrophy were less impaired.
Spatiotemporal Frequency and Direction Sensitivities of Human Visual Areas Measured Using fMRI
Creators: name: Singh, K. D.
name: Smith, A. T.
name: Greenlee, Mark W.
Publisher: name: Universität Regensburg
Year: 2000
Subjects: subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Using functional magnetic resonance imaging (fMRI) we have studied the variation in response magnitude, in each visual area (V1–V5), as a function of spatial frequency (SF), temporal frequency (TF) and unidirectional motion versus counterphase flicker. Each visual area was identified in each subject using a combination of retinotopic mapping fMRI and cortical flattening techniques. A drifting (or counterphasing) sinusoidal grating was used as the stimulus in a study in which we parametrically varied SF between 0.4 and 7 cycles/degree and TF between 0 and 18 Hz. For each experiment we constructed fMRI amplitude tuning curves, averaged across subjects, for each visual area. The tuning curves that resulted are consistent with the known physiological properties of cells in the corresponding macaque visual areas, previous functional imaging studies, and in the case of V1, the psychophysically determined contrast sensitivity functions for spatial and temporal frequency. In the case of V3A, the SF tuning functions obtained were more similar to those found in single cell studies of macaque V3 rather than macaque V3A. All areas showed at least a moderate preference for directed versus counterphasing motion with V5 showing the largest preference. Visual areas V1, V2, V3, and V3A showed more direction sensitivity at low spatial frequencies, while VP, V4, and V5 had the highest drifting versus counterphasing ratios for higher spatial frequencies.
Cortical activation evoked by visual mental imagery as measured by fMRI
Creators: name: Knauff, Markus
name: Kassubek, Jan
name: Mulack, Thomas
name: Greenlee, Mark W.
Publisher: name: Universität Regensburg
Year: 2000
Subjects: subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: One of the major controversies in cognitive neuroscience is whether the primary visual cortex and nearby areas are involved in visual mental imagery. In an fMRI study we examined the brain activity of 10 healthy subjects under different task conditions: in the perception condition subjects saw complex geometrical shapes and had to decide whether other highlighted stimuli fell inside or outside the figure. In the imagery condition subjects saw only the highlighted stimuli and were instructed to imagine the previously studied geometrical shapes to solve the same task. Although the behavioral data show a distance effect that would be expected based on topographically organized mental images, the functional imaging data do not show increased activity in the primary visual cortex in the imagery condition. In the occipital cortex a slightly increased activity was found only in the visual association cortex (BA 19), whereas the highest activation was observed in the parietal cortex (BA 7 and 40). The results of the study do not support the assumption that the primary visual cortex is involved in visual mental imagery, but rather that a network of spatial subsystems and higher visual areas appears to be involved.