cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Dynamical bi-stability of single-molecule junctions: A combined experimental/theoretical study of PTCDA on Ag(111)
Creators: name: Brumme, Thomas
name: Neucheva, Olga
name: Toher, Cormac
name: Gutiérrez, Rafael
name: Weiss, Christian
name: Temirov, Ruslan
name: Greuling, Andreas
name: Kaczmarski, Marcin
name: Rohlfing, Michael
name: Tautz, Stefan
name: Cuniberti, Gianaurelio
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The dynamics of a molecular junction consisting of a PTCDA molecule between the tip of a scanning tunneling microscope and a Ag(111) surface have been investigated experimentally and theoretically. Repeated switching of a PTCDA molecule between two conductance states is studied by low-temperature scanning tunneling microscopy for the first time, and is found to be dependent on the tip-substrate distance and the applied bias. Using a minimal model Hamiltonian approach combined with density-functional calculations, the switching is shown to be related to the scattering of electrons tunneling through the junction, which progressively excite the relevant chemical bond. Depending on the direction in which the molecule switches, different molecular orbitals are shown to dominate the transport and thus the vibrational heating process. This in turn can dramatically affect the switching rate, leading to non-monotonic behavior with respect to bias under certain conditions. In this work, rather than simply assuming a constant density of states as in previous works, it was modeled by Lorentzians. This allows for the successful description of this non-monotonic behavior of the switching rate, thus demonstrating the importance of modeling the density of states realistically.
description: 20 pages, 6 figures, 1 table
Tuning graphene’s electronic and transport properties via adatom deposition
Creators: name: Khademi, Ali
Publisher: name: University of British Columbia
Year: 2017

description: This thesis investigates the effect of adatom deposition, especially alkali and heavy adatoms, on graphene’s electronic and transport properties. While there are many theoretical predictions for tuning graphene’s properties via adatom deposition, only a few of them have been observed. Solving this enigma of inconsistency between theory and experiment raises the need for deeper experimental investigation of this matter. To achieve this goal, an experimental set up was built which enables us to evaporate different metal adatoms on graphene samples while they are at cryogenic temperatures and ultra-high vacuum (UHV) conditions. The critical role of in situ high-temperature annealing in creating reliable interactions between adatoms and graphene is observed. This contradicts the commonly accepted assumption in the transport community that placing a graphene sample in UHV and performing in situ 400-500 K annealing is enough to provide a reliable adatom-graphene interaction. Even charge doping by alkali atoms (Li), which is arguably the simplest of all adatom effects, cannot be achieved completely without in situ 900 K annealing. This observation may explain the difficulty many groups have faced in inducing superconductivity, spin-orbit interaction, or similar electronic modifications to graphene by adatom deposition, and it points toward a straightforward, if experimentally challenging, solution. The first experimental evidence of short-range scattering due to alkali adatoms in graphene is presented in this thesis, a result that contradicts the naive expectation that alkali adatoms on graphene only cause long-range Coulomb scattering. The induced short-range scattering by Li caused decline of intervalley time and length (i.e., enhancement of intervalley scattering). No signatures of theoretically predicted superconductivity of Li doped graphene were observed down to 3 K. Cryogenic deposition of copper increased the dephasing rate of graphene. This increase in dephasing rate is either a sign of inducing spin-orbit interaction or magnetic moments by copper. No similar effect was observed for indium.
Percolation of Color Sources and the Shear Viscosity of the QGP in Central A-A Collisions at RHIC and LHC Energies
Creators: name: de Deus, J. Dias
name: Hirsch, A. S.
name: Pajares, C.
name: Scharenberg, R. P.
name: Srivastava, B. K.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The Color String Percolation Model (CSPM) is used to determine the shear viscosity to entropy ratio ($η/s$) of the Quark-Gluon Plasma (QGP) produced in Au-Au collisions at $\sqrt{s_{NN}}$ = 200 GeV at RHIC and Pb-Pb at $\sqrt{s_{NN}}$ = 2.76 TeV at LHC. The relativistic kinetic theory relation for $η/s$ is evaluated using CSPM values for the temperature and the mean free path of the QGP constituents. The experimental charged hadron transverse momentum spectrum is used to determine the percolation density parameter $ξ$ in Au-Au collisions (STAR). For Pb-Pb at $\sqrt{s_{NN}}$ = 2.76 TeV $ξ$ values are obtained from the extrapolation at RHIC energy. The value of $η/s$ is 0.204$\pm$0.020 and 0.262$\pm$0.026 at the CSPM initial temperatures of 193.6$\pm$3 MeV (RHIC) and 262.2 $\pm$13 MeV (LHC) respectively. These values are 2.5 and 3.3 times the AdS/CFT conjectured lower bound $1/4π$. We compare the CSPM $η/s$ analytic expression with weak coupling (wQGP) and strong coupling (sQGP) calculations. This indicates that the QGP is a strongly coupled fluid in the phase transition region.
description: 4 pages, 3 figures Accepted for publication in European Physical Journal C (Particles & Fields)
Effects of Attention to Auditory Motion on Cortical Activations during Smooth Pursuit Eye Tracking
Creators: name: Baumann, Oliver
name: Greenlee, Mark W.
Publisher: name: Universität Regensburg
Year: 2009
Subjects: subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Background In contrast to traditional views that consider smooth pursuit as a relatively automatic process, evidence has been reported for the importance of attention for accurate pursuit performance. However, the exact role that attention might play in the maintenance of pursuit remains unclear. Methodology/Principal Findings We analysed the neuronal activity associated with healthy subjects executing smooth pursuit eye movements (SPEM) during concurrent attentive tracking of a moving sound source, which was either in-phase or in antiphase to the executed eye movements. Assuming that attentional resources must be allocated to the moving sound source, the simultaneous execution of SPEM and auditory tracking in diverging directions should result in increased load on common attentional resources. By using an auditory stimulus as a distractor rather then a visual stimulus we guaranteed that cortical activity cannot be caused by conflicts between two simultaneous visual motion stimuli. Our results revealed that the smooth pursuit task with divided attention led to significantly higher activations bilaterally in the posterior parietal cortex and lateral and medial frontal cortex, presumably containing the parietal, frontal and supplementary eye fields respectively. Conclusions The additional cortical activation in these areas is apparently due to the process of dividing attention between the execution of SPEM and the covert tracking of the auditory target. On the other hand, even though attention had to be divided the attentional resources did not seem to be exhausted, since the identification of the direction of the auditory target and the quality of SPEM were unaffected by the congruence between visual and auditory motion stimuli. Finally, we found that this form of task-related attention modulated not only the cortical pursuit network in general but also affected modality specific and supramodal attention regions.
Quantum error mitigation in optimized circuits for particle-density correlations in real-time dynamics of the Schwinger model
Creators: name: Pomarico, Domenico
name: Pandey, Mahul
name: Cioli, Riccardo
name: Dell'Anna, Federico
name: Pascazio, Saverio
name: Pepe, Francesco V.
name: Facchi, Paolo
name: Ercolessi, Elisa
Publisher: name: arXiv
Year: 2025
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum computing gives direct access to the study of real-time dynamics of quantum many-body systems. In principle, it is possible to directly calculate non-equal-time correlation functions, from which one can detect interesting phenomena, such as the presence of quantum scars or dynamical quantum phase transitions. In practice, these calculations are strongly affected by noise, due to the complexity of the required quantum circuits. As a testbed for the evaluation of real-time evolution of observables and correlations, the dynamics of the Zn Schwinger model in a one dimensional lattice is considered. To control the computational cost, we adopt a quantum-classical strategy that reduces the dimensionality of the system by restricting the dynamics to the Dirac vacuum sector and optimizes the embedding into a qubit model by minimizing the number of three-qubit gates. We derive a digital circuit implementation of the time-evolution of particle-density correlation operators and their correlation, comparing results from exact evolution, bare noisy simulations and simulations with different error mitigation techniques. For the evolution of the particle-density operators we also perform runs on a physical IBM quantum device.
Targeted activity of histone deacetylase inhibition in synovial sarcoma
Creators: name: Laporte, Aimée Nicole
Publisher: name: University of British Columbia
Year: 2017

description: Synovial sarcoma is an aggressive soft tissue cancer affecting primarily adolescents and young adults and characterized by the known chimeric fusion oncoprotein SS18-SSX resulting from a t(X;18) translocation. Oncoprotein-mediated interactions with chromatin-modification proteins are known to influence transformation; however targeted therapies are not currently available. Patients remain at high-risk for local recurrence and metastasis and see a 10-year survival rate of approximately 50%. Accordingly, it was hypothesized that therapeutic compounds able to disrupt the SS18-SSX driving complex would be clinically effective against synovial sarcoma. The proximity ligation assay was employed to study the drug-mediated disruption of the key SS18-SSX-mediated protein interactions that drive sarcomagenesis, and was developed for use to demonstrate targeted drug efficacy. Results identified HDAC inhibitors as potent in disrupting the oncogenic protein complex. The combination of HDAC and proteasome inhibitors was further found to be synergistic against synovial sarcoma. This pre-clinical study was used as support for a novel clinical trial proposal for translocation-associated soft tissue sarcomas. The effects of HDAC inhibition on genome-wide transcription patterns was further assessed by RNA-seq analysis. Uniquely to synovial sarcoma, it was revealed that HDAC inhibition elicits loss of the SS18-SSX oncoprotein and provokes significant pro-apoptotic BIK expression correlating to CDKN2A reactivation. From this, the contributing role of CDKN2A reactivation and reactive oxygen species accumulation in HDAC-inhibitor mediated apoptosis in synovial sarcoma was demonstrated.
Chiral Perturbation Theory, the ${1/N_c}$ expansion and Regge behaviour determine the structure of the lightest scalar meson
Creators: name: de Elvira, J. Ruiz
name: Peláez, J. R.
name: Pennington, M. R.
name: Wilson, D. J.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The leading $1/N_c$ behaviour of Unitarised Chiral Perturbation Theory distinguishes the nature of the $ρ$ and the $σ$. At one loop order the $ρ$ is a ${\bar q}q$ meson, while the $σ$ is not. However, semi-local duality between resonances and Regge behaviour cannot be satisfied for larger $N_c$, if such a distinction holds. While the $σ$ at $N_c=3$ is inevitably dominated by its di-pion component, Unitarised Chiral Perturbation Theory beyond one loop order reveals that as $N_c$ increases above 6-8, the $σ$ has a sub-dominant ${\bar q}q$ fraction up at 1.2 GeV. Remarkably this ensures semi-local duality is fulfilled for the range of $N_c \lesssim 15$, where the unitarisation procedure adopted applies.
description: 22 pages, 8 figures. Version to be published in Physical Review D
High-Fidelity Perceptual Long-Term Memory Revisited—and Confirmed
Creators: name: Magnussen, Svein
name: Greenlee, Mark W.
name: Aslaksen, Per Matti
name: Kildebo, Ole Øystein
Publisher: name: Universität Regensburg
Year: 2003
Subjects: subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Experiments on short-term perceptual memory for elemental visual attributes, such as contrast, motion, orientation, and spatial frequency, have relied on a delayed discrimination technique in which the subject compares two stimuli presented at different points in time and memory is indexed by discrimination thresholds measured for the different time intervals between reference and test. In a variant of this procedure, used in experiments on long-term memory, the presentation of a single reference is followed by a memory test that combines two-alternative forced-choice decisions with the method of constant stimuli. With this procedure, it is impossible to distinguish the effects of criterion-setting processes and memory on performance, but this confound can be eliminated by testing many subjects and having each subject make a single decision. The resulting “group thresholds” are stable across time intervals of 24 hr, confirming previous findings of high-fidelity storage in the long-term memory range.
Disentangled Modeling of Preferences and Social Influence for Group Recommendation
Creators: name: Ye, Guangze
name: Wu, Wen
name: Wang, Guoqing
name: Chen, Xi
name: Zheng, Hong
name: He, Liang
Publisher: name: arXiv
Year: 2025
Subjects: subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences

description: The group recommendation (GR) aims to suggest items for a group of users in social networks. Existing work typically considers individual preferences as the sole factor in aggregating group preferences. Actually, social influence is also an important factor in modeling users' contributions to the final group decision. However, existing methods either neglect the social influence of individual members or bundle preferences and social influence together as a unified representation. As a result, these models emphasize the preferences of the majority within the group rather than the actual interaction items, which we refer to as the preference bias issue in GR. Moreover, the self-supervised learning (SSL) strategies they designed to address the issue of group data sparsity fail to account for users' contextual social weights when regulating group representations, leading to suboptimal results. To tackle these issues, we propose a novel model based on Disentangled Modeling of Preferences and Social Influence for Group Recommendation (DisRec). Concretely, we first design a user-level disentangling network to disentangle the preferences and social influence of group members with separate embedding propagation schemes based on (hyper)graph convolution networks. We then introduce a socialbased contrastive learning strategy, selectively excluding user nodes based on their social importance to enhance group representations and alleviate the group-level data sparsity issue. The experimental results demonstrate that our model significantly outperforms state-of-the-art methods on two realworld datasets.
description: AAAI 2025 Oral
On the exact R charge for N=2 CS theories
Creators: name: Amariti, A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Recently it was argued that the exact R charge for three dimensional N=2 supersymmetric field theories extremizes the partition function localized on S^3. In this paper we check this conjecture by computing the R charge for SU(N)_k YM CS gauge theories at large k for many representations, and we test the agreement with the perturbative results.
description: 17 pages, 1 figure. references added, final version published in JHEP
Symmetric quivers, invariant theory, and saturation theorems for the classical groups
Creators: name: Sam, Steven V
Publisher: name: arXiv
Year: 2010
Subjects: subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 16G20, 20G05, 15A72, 14L30, 05E10

description: Let G denote either a special orthogonal group or a symplectic group defined over the complex numbers. We prove the following saturation result for G: given dominant weights λ^1, ..., λ^r such that the tensor product V_{Nλ^1} \otimes ... \otimes V_{Nλ^r} contains nonzero G-invariants for some N \ge 1, we show that the tensor product V_{2λ^1} \otimes ... \otimes V_{2λ^r} also contains nonzero G-invariants. This extends results of Kapovich-Millson and Belkale-Kumar and complements similar results for the general linear group due to Knutson-Tao and Derksen-Weyman. Our techniques involve the invariant theory of quivers equipped with an involution and the generic representation theory of certain quivers with relations.
description: 29 pages, no figures; v2: updated Theorem 2.4 to odd characteristic, added Remark 3.9, added references, corrected some definitions and typos
BIBO_12y_GM_Beh_codes
Creators: name: Yangwenshan Ou
Publisher: name: Zenodo
Year: 2022

description: The file includes the main R codes used for analyzing (1) gender-related differences in gut microbiota composition in BIBO samples at the age of 12 years, and (2) relations between the gut microbiota and child behavior (i.e., problem behavior and prosocial behavior) in the same samples, together with the potential role of gender in these relations.
Altered Activation Patterns within the Olfactory Network in Parkinson's Disease
Creators: name: Moessnang, Carolin
name: Frank, Gabriele
name: Bogdahn, Ulrich
name: Winkler, Jurgen
name: Greenlee, Mark W.
name: Klucken, Jochen
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: cortical reorganization, fMRI, neural networks, olfaction, PD
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Olfactory impairment is a consistent premotor symptom in sporadic Parkinson's disease (PD), presumably caused by pathological processes in the olfactory bulb and olfactory structures within mesolimbic brain areas. The objective of the present study was to obtain an in-depth insight into olfactory network dysfunction in PD patients. Event-related functional magnetic resonance imaging (3 T) was conducted with 16 early-stage PD patients and 16 matched controls during an odor detection task. Activation within the olfactory network was analyzed both in terms of strength of activation (whole-brain random effects, regions of interest [ROI] analysis based on the hemodynamic response function) as well as time-course characteristics (finite impulse response–based ROI analysis). Olfactory-induced activation in patients with PD in comparison to a standard activation pattern obtained from controls revealed profound hyperactivation in piriform and orbitofrontal cortices. However, whereas orbitofrontal areas seem to be unable to discriminate between signal and noise, primary olfactory cortex shows preserved discriminatory ability. These results support a complex network dysfunction that exceeds structural pathology observed in the olfactory bulb and mesolimbic cortices and thus demonstrate the important contribution of functional data to describe network dynamics occurring in the degenerating brain.
title: Handlungsleitfaden Intracting an Hochschulen
title: Kontinulierliche Steigerung der Energieeffizienz
Creators: name: Knissel, Jens
name: Ehlert, Marius
Publisher: name: Universität Kassel
Year: 2021
Subjects: subject: 370
subject: 690
subject: Hochschule
subject: Energieeinsparung
subject: Gebäude
subject: Finanzinstrument

description: gefördert vom Bundesministerium für Wirtschaft und Energie
Belief-propagation algorithm and the Ising model on networks with arbitrary distributions of motifs
Creators: name: Yoon, S.
name: Goltsev, A. V.
name: Dorogovtsev, S. N.
name: Mendes, J. F. F.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: We generalize the belief-propagation algorithm to sparse random networks with arbitrary distributions of motifs (triangles, loops, etc.). Each vertex in these networks belongs to a given set of motifs (generalization of the configuration model). These networks can be treated as sparse uncorrelated hypergraphs in which hyperedges represent motifs. Here a hypergraph is a generalization of a graph, where a hyperedge can connect any number of vertices. These uncorrelated hypergraphs are tree-like (hypertrees), which crucially simplify the problem and allow us to apply the belief-propagation algorithm to these loopy networks with arbitrary motifs. As natural examples, we consider motifs in the form of finite loops and cliques. We apply the belief-propagation algorithm to the ferromagnetic Ising model on the resulting random networks. We obtain an exact solution of this model on networks with finite loops or cliques as motifs. We find an exact critical temperature of the ferromagnetic phase transition and demonstrate that with increasing the clustering coefficient and the loop size, the critical temperature increases compared to ordinary tree-like complex networks. Our solution also gives the birth point of the giant connected component in these loopy networks.
description: 9 pages, 4 figures
The Relationship between Brain Oscillations and BOLD Signal during Memory Formation: A Combined EEG-fMRI Study
Creators: name: Hanslmayr, Simon
name: Volberg, Gregor
name: Wimber, Maria
name: Raabe, Markus
name: Greenlee, M. W.
name: Bäuml, Karl-Heinz
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Previous studies demonstrated that increases in the theta frequency band with concomitant decreases in the alpha/beta frequency band indicate successful memory formation. However, little is known about the brain regions and the cognitive processes that underlie these encoding-related oscillatory memory effects. We investigated this relationship using simultaneous EEG–fMRI recordings in humans during long-term memory encoding. In line with prior studies, we demonstrate that a decrease in beta power and an increase in theta power positively predict subsequent recall. In fMRI, stronger activity in the left inferior prefrontal cortex and the right parahippocampal gyrus correlated with successful memory formation. EEG source localization revealed that the subsequent memory effect in the beta band was localized in the left inferior prefrontal cortex, whereas the effect in the theta band was localized in medial temporal lobe regions. Trial-by-trial correlations between EEG and BOLD activity showed that beta power correlated negatively with left inferior prefrontal cortex activity. This correlation was more pronounced for items that could later be successfully recalled compared to items later forgotten. Based on these findings, we suggest that beta oscillations in the left inferior prefrontal cortex indicate semantic encoding processes, whereas theta oscillations in the medial temporal lobe reflect the binding of an item to its spatiotemporal context.
Zeta function regularization, anomaly and complex mass term
Creators: name: Mitra, P.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: If the zeta function regularization is used and a complex mass term considered for fermions, the phase does not appear in the fermion determinant. This is not a drawback of the regularization, which can recognize the phase through source terms, as demonstrated by the anomaly equation which is explicitly derived here for a complex mass term.
description: 7 pages
title: The Effects of X-Irradiation on the Metamorphosis and Budding of Aurelia aurita
Creators: name: Prokopchak, Michael John
Publisher: name: Old Dominion University Libraries
Year: 1984

description: With the aid of the Aurelia Metamorphosis Test System, the acute or subtle morphological and behavioral effects of irradiation on the Norfolk Aurelia aurita were described and the sensitivity to X-irradiation of those organisms receiving thyroxine and those not receiving thyroxine was compared. Levels of radiation were 0 (control), 5,000, 10,000, 15,000, 20,000 and 40,000 rads. Morphology of the ephyrae, statolith and rhopalia numbers were recorded using the light microscope, Developmental abnormalities of the scyphistomae and ephyrae were recorded with the scanning electron microscope and light microscope. Two major findings from this investigation were the absence of rhopalia and statoliths at 15,000 and 20,000 rads and the development of two-bodied scyphistomae. There was a significantly higher frequency of monster scyphistomae in the group exposed to thyroxine prior to irradiation than in the group not exposed to thyroxine prior to irradiation.
Neuronal Adaptation Effects in Decision Making
Creators: name: Theodoni, P.
name: Kovacs, G.
name: Greenlee, Mark W.
name: Deco, G.
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Recently, there has been an increased interest on the neural mechanisms underlying perceptual decision making. However, the effect of neuronal adaptation in this context has not yet been studied. We begin our study by investigating how adaptation can bias perceptual decisions. We considered behavioral data from an experiment on high-level adaptation-related aftereffects in a perceptual decision task with ambiguous stimuli on humans. To understand the driving force behind the perceptual decision process, a biologically inspired cortical network model was used. Two theoretical scenarios arose for explaining the perceptual switch from the category of the adaptor stimulus to the opposite, nonadapted one. One is noise-driven transition due to the probabilistic spike times of neurons and the other is adaptation-driven transition due to afterhyperpolarization currents. With increasing levels of neural adaptation, the system shifts from a noise-driven to an adaptation-driven modus. The behavioral results show that the underlying model is not just a bistable model, as usual in the decision-making modeling literature, but that neuronal adaptation is high and therefore the working point of the model is in the oscillatory regime. Using the same model parameters, we studied the effect of neural adaptation in a perceptual decision-making task where the same ambiguous stimulus was presented with and without a preceding adaptor stimulus. We find that for different levels of sensory evidence favoring one of the two interpretations of the ambiguous stimulus, higher levels of neural adaptation lead to quicker decisions contributing to a speed–accuracy trade off.
Assessing language dominance with functional MRI: The role of control tasks and statistical analysis
Creators: name: Dodoo-Schittko, Frank
name: Rosengarth, Katharina
name: Doenitz, Christian
name: Greenlee, Mark W.
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: Lateralization, Broca's, Presurgical, Semantic, Generation
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: There is a discrepancy between the brain regions revealed by functional neuroimaging techniques and those brain regions where a loss of function, either by lesion or by electrocortical stimulation, induces language disorders. To differentiate between essential and non-essential language-related processes, we investigated the effects of linguistic control tasks and different analysis methods for functional MRI data. Twelve subjects solved two linguistic generation tasks: (1) a verb generation task and (2) an antonym generation task (each with a linguistic control task on the phonological level) as well as two decision tasks of semantic congruency (each with a cognitive high-level control task). Differential contrasts and conjunction analyses were carried out on the single-subject level and an individual lateralization index (LI) was computed. On the group level we determined the percent signal change in the left inferior frontal gyrus (IFG: BA 44 and BA 45). The conjunction analysis of multiple language tasks led to significantly greater absolute LIs than the LIs based on the single task versus fixation contrasts. A further significant increase of the magnitude of the LIs could be achieved by using the phonological control conditions. Although the decision tasks appear to be more robust to changes in the statistical threshold, the combined generation tasks had an advantage over the decision tasks both for assessing language dominance and locating Broca's area. These results underline the need for conjunction analysis based on several language tasks to suppress highly task-specific processes. They also point to the need for high-level cognitive control tasks to partial out general, language supporting but not language critical processes. Higher absolute LIs, which reflect unambiguously hemispheric language dominance, can be thus obtained.
Timing everyday tasks and events
Creators: name: Fergusson, Janel
Publisher: name: University of British Columbia
Year: 2017

description: Many of the tasks we complete every day require us to attend to the passing of time or to use time information in some way. Everyday tasks frequently require us to use time information in a strategic, deliberate, and explicit way, such as when we wish to steep a cup of tea for 3 minutes or must leave to meet a colleague in 5 minutes. Much of the previous research on timing has used very short duration tasks, in the range of seconds. Several models have been developed to account for timing in short duration tasks, but it is not known which model(s) best fit timing of everyday intervals. This dissertation research was designed to determine whether the AGM or memory storage models can account for timing in the range of everyday intervals. Experiment 1 investigated the underlying pattern of estimates in the range of 1-5 minutes. Participants produced underestimates for all intervals. Experiments 2 and 3 used a framing manipulation to investigate the role of memory chunking in timing everyday durations. Participants who were instructed to focus on the present task produced intervals that were longer than participants who were instructed to focus on a future task, consistent with the idea that a present frame serves as a better organizing structure for the interval and results in fewer chunks. According to memory storage models, the number of items in memory is compared to a stored value in reference memory to determine how much time has passed. When stimuli are organized more cohesively, resulting in fewer chunks, it takes a longer time to accumulate the target number of chunks. Experiment 4 used feedback and an attentional manipulation to investigate the role of reference memory and attention to timing. Participants produced more accurate intervals following feedback, consistent with the idea that reference memory for everyday intervals is inaccurate. Attention had no effect on estimate duration, which is inconsistent with the AGM. Taken together, the results from these experiments suggest that memory storage models are a better fit for timing in the range of everyday intervals.
On the law of large numbers for Demazure modules of sl2hat
Creators: name: Bliem, Thomas
name: Kousidis, Stavros
Publisher: name: arXiv
Year: 2010
Subjects: subject: Representation Theory (math.RT)
subject: FOS: Mathematics

description: We determine the covariance of the weight distribution in level 1 Demazure modules of sl2hat. This allows us to prove a weak law of large numbers for these weight distributions, and leads to a conjecture about the asymptotic concentration of weights for arbitrary Demazure modules.
description: 15 pages, 5 figures
Maternal and psychosocial antecedents of anxiety and depression in extremely low gestational age newborns at age 15 years
Creators: name: Jara, Hernan
name: Cochran, David
name: Singh, Rachana
name: Oran, Ali
name: Kuban, Karl C. K.
name: Jensen, Elizabeth
name: Gogcu, Semsa
name: O’Shea, T. Michael
name: Msall, Michael E.
name: Hooper, Stephen R.
name: Kim, Sohye
name: Santos, Hudson
name: Washburn, Lisa
name: Venuti, Lauren
name: Fry, Rebecca C.
name: Jalnapurkar, Isha
name: Joseph, Robert
name: Frazier, Jean A.
name: Hanson, Shannon
name: ELGAN Study Investigators
Publisher: name: Frontiers
Year: 2024

description: The prevalence of many psychiatric symptoms, including anxiety and depression, is higher in individuals born extremely preterm (EP) than in term-born individuals during childhood and adolescence. In this prospective study of adolescents born EP, we examined associations between early-life risk factors (prenatal maternal health conditions, socioeconomic and social factors) and anxiety and depression at 15 years of age. We included 682 participants (53.2% White, 57.8% male) who were born <28 weeks gestation. Data on demographic factors, maternal health conditions and socioeconomic status (SES) were collected in the first postnatal month, and data on the outcomes (anxiety and depression) were collected at 15 years by a structured clinical diagnostic interview. At the 15-year visit, the mother reported on her own experiences of childhood trauma. Logistic regression models were used to evaluate associations between maternal health indicators, SES factors and mothers' childhood trauma and adolescent outcome variables of anxiety, depression and both anxiety and/or depression, adjusting for potential confounding factors and expressed as adjusted odds ratios (aOR) and 95% confidence intervals (CI). Maternal pre-pregnancy obesity was associated with anxiety (aOR: 1.84, 95% CI: 1.15, 2.95) and depression (aOR: 1.95, 95% CI: 1.17, 3.23) in adolescents at age 15. Maternal exposure to active or second-hand smoke was associated with depression (aOR: 1.8, 95% CI: 1.08, 3.00) and with anxiety and depression (aOR: 2.83, 95% CI: 1.51, 5.31) at age 15. Other maternal pre-pregnancy health indicators of interest including asthma, hypertension and diabetes mellitus did not demonstrate significant associations with symptoms of anxiety or depression in adolescents at age 15 in univariable and multivariate analyses. Maternal childhood experience of parental upheaval was associated with anxiety and depression (OR: 1.91, 95% CI: 1.01, 3.55) in adolescents, and maternal childhood experience of victim violence was linked with anxiety (OR: 2.4, 95% CI: 1.22, 4.62) and anxiety and depression (OR: 2.49, 95% CI: 1.05, 5.42). These findings suggest that prenatal maternal health and socioeconomic factors contribute to psychiatric disorders among adolescents born EP. These factors could serve as targets for interventions to improve mental health of individuals born EP.
Prefrontally Driven Downregulation of Neural Synchrony Mediates Goal-Directed Forgetting
Creators: name: Hanslmayr, Simon
name: Volberg, Gregor
name: Wimber, Maria
name: Oehler, Nora
name: Staudigl, Tobias
name: Hartmann, Thomas
name: Raabe, Markus
name: Greenlee, M. W.
name: Bäuml, Karl-Heinz T.
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Neural synchronization between distant cell assemblies is crucial for the formation of new memories. To date, however, it remains unclear whether higher-order brain regions can adaptively regulate neural synchrony to control memory processing in humans. We explored this question in two experiments using a voluntary forgetting task. In the first experiment, we simultaneously recorded electroencephalography along with fMRI. The results show that a reduction in neural synchrony goes hand-in-hand with a BOLD signal increase in the left dorsolateral prefrontal cortex (dlPFC) when participants are cued to forget previously studied information. In the second experiment, we directly stimulated the left dlPFC with repetitive transcranial magnetic stimulation during the same task, and show that such stimulation specifically boosts the behavioral forgetting effect and induces a reduction in neural synchrony. These results suggest that prefrontally driven downregulation of long-range neural synchronization mediates goal-directed forgetting of long-term memories.
Basic aspects of ferroelectricity induced by noncollinear alignment of spins
Creators: name: Solovyev, I. V.
Publisher: name: arXiv
Year: 2025
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Basic principles of ferroelectric activity induced by the noncollinear spins are reviewed. There is a fundamental reason why the inversion symmetry can be broken by magnetic order. Such situation occurs when the magnetic order simultaneously involves ferromagnetic ($F$) and antiferromagnetic ($A$) patterns, transforming under the spatial inversion $\mathcal{I}$ and time reversal $\mathcal{T}$ as $\mathcal{I}F=F$ and $\mathcal{IT}A=A$. The incompatibility of these two conditions breaks the inversion symmetry, imposing a constraint on possible dependencies of polarization on directions of spins, which can include only antisymmetric coupling and single-ion anisotropy in the from $\vec{P} = \vec{\boldsymbol{\mathcal{P}}}_{12} [ \boldsymbol{e}_{1} \times \boldsymbol{e}_{2} ] + \boldsymbol{e}_{1} \vec{\mathbbΠ} \boldsymbol{e}_{1} - \boldsymbol{e}_{2} \vec{\mathbbΠ} \boldsymbol{e}_{2}$. $\vec{\boldsymbol{\mathcal{P}}}_{12}$ can be evaluated in the framework of superexchange theory, resulting in $\vec{\boldsymbol{\mathcal{P}}}_{12} \sim \vec{\boldsymbol{r}}_{12}^{\phantom{0}}$, where $\vec{\boldsymbol{r}}_{12}^{\phantom{0}}$ is the part of the position operator produced by the spin-orbit coupling. $\vec{\boldsymbol{r}}_{12}$ remains invariant under $\mathcal{I}$, explaining why noncollinear spins can induce $\vec{P}$ even in the centrosymmetric case. The properties of $\vec{\boldsymbol{r}}_{12}$ are rationalized from the viewpoint of symmetry of the Kramers states. The Katsura-Nagaosa-Balatsky rule $\vec{P} \propto \vecε_{21} \times [\boldsymbol{e}_{1} \times \boldsymbol{e}_{2}]$ ($\vecε_{21}$ being the bond direction) is justified only for relatively high symmetry. The single-ion anisotropy vanishes for the spin 1/2 or if magnetic ions are located in the inversion centers. The properties of known multiferroics are reconsidered from the viewpoint of these principles.
description: 20 pages, 12 figures
An MRI-compatible caloric stimulation device for the investigation of human vestibular cortex
Creators: name: Frank, Sebastian M.
name: Greenlee, Mark W.
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: Caloric vestibular stimulation, fMRI, Self-motion perception, Vestibular cortex, Caloric nystagmus
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: Background Self-motion perception involves the integration of vestibular, visual, somatosensory and other sensory cues. The neural responses to caloric vestibular stimulation (CVS) in humans have been investigated with functional magnetic resonance imaging (fMRI). New method We developed an fMRI-compatible, bithermal caloric stimulation device for repeated CVS. Tempered water is pumped via a closed-loop tube-system to one or both ear canals. Water temperature transmits to the surface of the ear canal via a small glass-pod. For our purposes we used hot (47–49 °C), cold (5–7.5 °C), or warm for baseline (30–32.5 °C). The pods are integrated in the MRI ear protection and connected to water influx and efflux tubes. With our device we can apply multiple vestibular stimulation and baseline trials consecutively. Control measurements indicate that the applied temperatures are stable across trials. MRI-signal differences due to water flow and water temperature are restricted to the area surrounding the pod and are unlikely to intrude into brain tissue. Results Vestibular stimulation with our device elicits caloric nystagmus when no central fixation is presented. We validated our system by conducting a CVS experiment during fMRI-scanning. Participants indicated the presence or absence of a self-motion sensation. Periods of self motion yielded activation in the cortical vestibular network including putative human parieto-insular vestibular cortex (PIVC). Comparison with existing methods Our closed-loop device eliminates many problems associated with caloric stimulation during fMRI. Conclusions Our device allows researchers to explore neural responses to CVS and those evoked by combined sensory stimulation.
RNA-Bloom : de novo RNA-seq assembly with Bloom filters
Creators: name: Nip, Ka Ming
Publisher: name: University of British Columbia
Year: 2017

description: High-throughput RNA sequencing (RNA-seq) is primarily used in measuring gene expression, quantifying transcript abundance, and building reference transcriptomes. Without bias from a reference sequence, de novo RNA-seq assembly is particularly useful for building new reference transcriptomes, detecting fusion genes, and discovering novel spliced transcripts. This is a challenging problem, and to address it at least eight approaches, including Trans-ABySS and Trinity, were developed within the past decade. For instance, using Trinity and 12 CPUs, it takes approximately one and a half day to assemble a human RNA-seq sample of over 100 million read pairs and requires up to 80 GB of memory. While the high memory usage typical of de novo RNA-seq assemblers may be alleviated by distributed computing, access to a high-performance computing environment is a requirement that may be limiting for smaller labs. In my thesis, I present a novel de novo RNA-seq assembler, “RNA-Bloom,” which utilizes compact data structures based on Bloom filters for the storage of k-mer counts and the de Bruijn graph in memory. Compared to Trans-ABySS and Trinity, RNA-Bloom can assemble a human transcriptome with comparable accuracy using nearly half as much memory and half the wall-clock time with 12 threads.
A study of blow-ups in the Keller-Segel model of chemotaxis
Creators: name: Fatkullin, Ibrahim
Publisher: name: arXiv
Year: 2010
Subjects: subject: Analysis of PDEs (math.AP)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We study the Keller-Segel model of chemotaxis and develop a composite particle-grid numerical method with adaptive time stepping which allows us to accurately resolve singular solutions. The numerical findings (in two dimensions) are then compared with analytical predictions regarding formation and interaction of singularities obtained via analysis of the stochastic differential equations associated with the Keller-Segel model.
Rezension: Elena Seoane and Cristina Suárez-Gómez (eds.), World Englishes: New theoretical and methodological considerations (Varieties of English Around the World G57). Amsterdam: John Benjamins, 2016
Creators: name: Buschfeld, Sarah
Publisher: name: Universität Regensburg
Year: 2018
Subjects: subject: 420 Englisch

description: OA-Komponente aus Allianzlizenz
Complete classification of 1D gapped quantum phases in interacting spin systems
Creators: name: Chen, Xie
name: Gu, Zheng-Cheng
name: Wen, Xiao-Gang
Publisher: name: arXiv
Year: 2011
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum phases with different orders exist with or without breaking the symmetry of the system. Recently, a classification of gapped quantum phases which do not break time reversal, parity or on-site unitary symmetry has been given for 1D spin systems in [X. Chen, Z.-C. Gu, and X.-G. Wen, Phys. Rev. B \textbf{83}, 035107 (2011); arXiv:1008.3745]. It was found that, such symmetry protected topological (SPT) phases are labeled by the projective representations of the symmetry group which can be viewed as a symmetry fractionalization. In this paper, we extend the classification of 1D gapped phases by considering SPT phases with combined time reversal, parity, and/or on-site unitary symmetries and also the possibility of symmetry breaking. We clarify how symmetry fractionalizes with combined symmetries and also how symmetry fractionalization coexists with symmetry breaking. In this way, we obtain a complete classification of gapped quantum phases in 1D spin systems. We find that in general, symmetry fractionalization, symmetry breaking and long range entanglement(present in 2 or higher dimensions) represent three main mechanisms to generate a very rich set of gapped quantum phases. As an application of our classification, we study the possible SPT phases in 1D fermionic systems, which can be mapped to spin systems by Jordan-Wigner transformation.
description: 15 pages, 3 figures
Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci
Creators: name: Fellner, Marie-Christin
name: Volberg, Gregor
name: Wimber, Maria
name: Goldhacker, Markus
name: Greenlee, Mark W.
name: Hanslmayr, Simon
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: EEG; fMRI; memory encoding; method of loci; mnemonics; theta oscillations
subject: 150 Psychologie
subject: 570 Biowissenschaften, Biologie

description: The method of loci is one, if not the most, efficient mnemonic encoding strategy. This spatial mnemonic combines the core cognitive processes commonly linked to medial temporal lobe (MTL) activity: spatial and associative memory processes. During such processes, fMRI studies consistently demonstrate MTL activity, while electrophysiological studies have emphasized the important role of theta oscillations (3–8 Hz) in the MTL. However, it is still unknown whether increases or decreases in theta power co-occur with increased BOLD signal in the MTL during memory encoding. To investigate this question, we recorded EEG and fMRI separately, while human participants used the spatial method of loci or the pegword method, a similarly associative but nonspatial mnemonic. The more effective spatial mnemonic induced a pronounced theta power decrease source localized to the left MTL compared with the nonspatial associative mnemonic strategy. This effect was mirrored by BOLD signal increases in the MTL. Successful encoding, irrespective of the strategy used, elicited decreases in left temporal theta power and increases in MTL BOLD activity. This pattern of results suggests a negative relationship between theta power and BOLD signal changes in the MTL during memory encoding and spatial processing. The findings extend the well known negative relation of alpha/beta oscillations and BOLD signals in the cortex to theta oscillations in the MTL.
Minimum K_2,3-saturated Graphs
Creators: name: Chen, Ya-Chen
Publisher: name: arXiv
Year: 2010
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05C35, 05C38

description: A graph is K_{2,3}-saturated if it has no subgraph isomorphic to K_{2,3}, but does contain a K_{2,3} after the addition of any new edge. We prove that the minimum number of edges in a K_{2,3}-saturated graph on n >= 5 vertices is sat(n, K_{2,3}) = 2n - 3.
description: 12 pages; improve writing, add more detailed explanation, minor corrections