TY - GEN A1 - Valsecchi, Matteo A1 - Dimigen, Olaf A1 - Kliegl, Reinhold A1 - Sommer, Werner A1 - Turatto, Massimo T1 - Microsaccadic Inhibition and P300 Enhancement in a Visual Oddball Task N2 - It has recently been demonstrated that the presentation of a rare target in a visual oddball paradigm induces a prolonged inhibition of microsaccades. In the field of electrophysiology, the amplitude of the P300 component in event-related potentials (ERP) has been shown to be sensitive to the stimulus category (target vs. non target) of the eliciting stimulus, its overall probability, and the preceding stimulus sequence. In the present study we further specify the functional underpinnings of the prolonged microsaccadic inhibition in the visual oddball task, showing that the stimulus category, the frequency of a stimulus and the preceding stimulus sequence influence microsaccade rate. Furthermore, by co-recording ERPs and eye-movements, we were able to demonstrate that, despite being largely sensitive to the same experimental manipulation, the amplitude of P300 and the microsaccadic inhibition predict each other very weakly, and thus constitute two independent measures of the brain’s response to rare targets in the visual oddball paradigm. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 256 KW - Visual Oddball Paradigm KW - Microsaccades KW - Microsaccadic Inhibition KW - ERPs KW - P300Psychophysiology KW - 46 (3) 2009 KW - S. 635-644 Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57170 ER - TY - GEN A1 - Boston, Marisa Ferrara A1 - Hale, John T. A1 - Vasishth, Shravan A1 - Kliegl, Reinhold T1 - Parallel processing and sentence comprehension difficulty N2 - Eye fixation durations during normal reading correlate with processing difficulty but the specific cognitive mechanisms reflected in these measures are not well understood. This study finds support in German readers’ eyefixations for two distinct difficulty metrics: surprisal, which reflects the change in probabilities across syntactic analyses as new words are integrated, and retrieval, which quantifies comprehension difficulty in terms of working memory constraints. We examine the predictions of both metrics using a family of dependency parsers indexed by an upper limit on the number of candidate syntactic analyses they retain at successive words. Surprisal models all fixation measures and regression probability. By contrast, retrieval does not model any measure in serial processing. As more candidate analyses are considered in parallel at each word, retrieval can account for the same measures as surprisal. This pattern suggests an important role for ranked parallelism in theories of sentence comprehension. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 252 Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57159 ER - TY - GEN A1 - Boston, Marisa Ferrara A1 - Hale, John A1 - Kliegl, Reinhold A1 - Patil, Umesh A1 - Vasishth, Shravan T1 - Parsing costs as predictors of reading difficulty: An evaluation using the Potsdam Sentence Corpus N2 - The surprisal of a word on a probabilistic grammar constitutes a promising complexity metric for human sentence comprehension difficulty. Using two different grammar types, surprisal is shown to have an effect on fixation durations and regression probabilities in a sample of German readers’ eye movements, the Potsdam Sentence Corpus. A linear mixed-effects model was used to quantify the effect of surprisal while taking into account unigram and bigram frequency, word length, and empirically-derived word predictability; the so-called “early” and “late” measures of processing difficulty both showed an effect of surprisal. Surprisal is also shown to have a small but statistically non-significant effect on empirically-derived predictability itself. This work thus demonstrates the importance of including parsing costs as a predictor of comprehension difficulty in models of reading, and suggests that a simple identification of syntactic parsing costs with early measures and late measures with durations of post-syntactic events may be difficult to uphold. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 253 Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57139 ER - TY - GEN A1 - Angele, Bernhard A1 - Slattery, Timothy J. A1 - Yang, Jinmian A1 - Kliegl, Reinhold A1 - Rayner, Keith T1 - Parafoveal processing in reading: Manipulating n+1 and n+2 previews simultaneously N2 - The boundary paradigm (Rayner, 1975) with a novel preview manipulation was used to examine the extent of parafoveal processing of words to the right of fixation. Words n+1 and n+2 had either correct or incorrect previews prior to fixation (prior to crossing the boundary location). In addition, the manipulation utilized either a high or low frequency word in word n+1 location on the assumption that it would be more likely that n+2 preview effects could be obtained when word n+1 was high frequency. The primary findings were that there was no evidence for a preview benefit for word n+2 and no evidence for parafoveal-on-foveal effects when word n+1 is at least four letters long. We discuss implications for models of eye-movement control in reading. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 251 Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57128 ER - TY - GEN A1 - Ming, Yan A1 - Kliegl, Reinhold A1 - Shu, Hua A1 - Pan, Jinger A1 - Zhou, Xiaolin T1 - Parafoveal Load of Word N+1 Modulates Preprocessing Effectivenessof Word N+2 in Chinese Reading N2 - Preview benefits (PBs) from two words to the right of the fixated one (i.e., word N+2)and associated parafoveal-on-foveal effects are critical for proposals of distributed lexical processing during reading. This experiment examined parafoveal processing during reading of Chinese sentences, using a boundary manipulation of N+2-word preview with low- and high-frequency words N+1. The main findings were (a) an identity PB for word N+2 that was (b) primarily observed when word N+1 was of high frequency (i.e., an interaction between frequency of word N+1 and PB for word N+2), and (c) a parafoveal-on-foveal frequency effect of word N+1 for fixation durations on word N. We discuss implications for theories of serial attention shifts and parallel distributed processing of words during reading. T2 - Ming Yan; Reinhold Kliegl; Hua Shu; Jinger Pan; Xiaolin Zhou T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 250 Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57103 ER - TY - GEN A1 - Kliegl, Reinhold A1 - Masson, Michael E. J. A1 - Richter, Eike M. T1 - A linear mixed model analysis of masked repetition priming N2 - We examined individual differences in masked repetition priming by re-analyzing item-level response-time (RT) data from three experiments. Using a linear mixed model (LMM) with subjects and items specified as crossed random factors, the originally reported priming and word-frequency effects were recovered. In the same LMM, we estimated parameters describing the distributions of these effects across subjects. Subjects’ frequency and priming effects correlated positively with each other and negatively with mean RT. These correlation estimates, however, emerged only with a reciprocal transformation of RT (i.e., -1/RT), justified on the basis of distributional analyses. Different correlations, some with opposite sign, were obtained (1) for untransformed or logarithmic RTs or (2) when correlations were computed using within-subject analyses. We discuss the relevance of the new results for accounts of masked priming, implications of applying RT transformations, and the use of LMMs as a tool for the joint analysis of experimental effects and associated individual differences. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 247 Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57073 ER - TY - GEN A1 - Kliegl, Reinhold A1 - Bates, Douglas T1 - International Collaboration in Psychology is on the Rise N2 - There has been a substantial increase in the percentage for publications with co-authors located in departments from different countries in 12 major journals of psychology. The results are evidence for a remarkable internationalization of psychological research, starting in the mid 1970s and increasing in rate at the beginning of the 1990s. This growth occurs against a constant number of articles with authors from the same country; it is not due to a concomitant increase in the number of co-authors per article. Thus, international collaboration in psychology is obviously on the rise. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 244 Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57045 ER - TY - GEN A1 - Dimigen, Olaf A1 - Valsecchi, Matteo A1 - Sommer, Werner A1 - Kliegl, Reinhold T1 - Human Microsaccade-Related Visual Brain Responses N2 - Microsaccades are very small, involuntary flicks in eye position that occur on average once or twice per second during attempted visual fixation. Microsaccades give rise to EMG eye muscle spikes that can distort the spectrum of the scalp EEG and mimic increases in gamma band power. Here we demonstrate that microsaccades are also accompanied by genuine and sizeable cortical activity, manifested in the EEG. In three experiments, high-resolution eye movements were corecorded with the EEG: during sustained fixation of checkerboard and face stimuli and in a standard visual oddball task that required the counting of target stimuli. Results show that microsaccades as small as 0.15° generate a field potential over occipital cortex and midcentral scalp sites 100 –140 ms after movement onset, which resembles the visual lambda response evoked by larger voluntary saccades. This challenges the standard assumption of human brain imaging studies that saccade-related brain activity is precluded by fixation, even when fully complied with. Instead, additional cortical potentials from microsaccades were present in 86% of the oddball task trials and of similar amplitude as the visual response to stimulus onset. Furthermore, microsaccade probability varied systematically according to the proportion of target stimuli in the oddball task, causing modulations of late stimulus-locked event-related potential (ERP) components. Microsaccades present an unrecognized source of visual brain signal that is of interest for vision research and may have influenced the data of many ERP and neuroimaging studies. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 240 Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-56923 ER - TY - THES A1 - Popovic, Jelena T1 - Novel lithium iron phosphate materials for lithium-ion batteries T1 - Neuartige Lithium-Eisen-Phosphat-Materialien für Lithium-Ionen-Batterien N2 - Conventional energy sources are diminishing and non-renewable, take million years to form and cause environmental degradation. In the 21st century, we have to aim at achieving sustainable, environmentally friendly and cheap energy supply by employing renewable energy technologies associated with portable energy storage devices. Lithium-ion batteries can repeatedly generate clean energy from stored materials and convert reversely electric into chemical energy. The performance of lithium-ion batteries depends intimately on the properties of their materials. Presently used battery electrodes are expensive to be produced; they offer limited energy storage possibility and are unsafe to be used in larger dimensions restraining the diversity of application, especially in hybrid electric vehicles (HEVs) and electric vehicles (EVs). This thesis presents a major progress in the development of LiFePO4 as a cathode material for lithium-ion batteries. Using simple procedure, a completely novel morphology has been synthesized (mesocrystals of LiFePO4) and excellent electrochemical behavior was recorded (nanostructured LiFePO4). The newly developed reactions for synthesis of LiFePO4 are single-step processes and are taking place in an autoclave at significantly lower temperature (200 deg. C) compared to the conventional solid-state method (multi-step and up to 800 deg. C). The use of inexpensive environmentally benign precursors offers a green manufacturing approach for a large scale production. These newly developed experimental procedures can also be extended to other phospho-olivine materials, such as LiCoPO4 and LiMnPO4. The material with the best electrochemical behavior (nanostructured LiFePO4 with carbon coating) was able to delive a stable 94% of the theoretically known capacity. N2 - Konventionelle Energiequellen sind weder nachwachsend und daher nachhaltig nutzbar, noch weiterhin langfristig verfügbar. Sie benötigen Millionen von Jahren um gebildet zu werden und verursachen in ihrer Nutzung negative Umwelteinflüsse wie starke Treibhausgasemissionen. Im 21sten Jahrhundert ist es unser Ziel nachhaltige und umweltfreundliche, sowie möglichst preisgünstige Energiequellen zu erschließen und nutzen. Neuartige Technologien assoziiert mit transportablen Energiespeichersystemen spielen dabei in unserer mobilen Welt eine große Rolle. Li-Ionen Batterien sind in der Lage wiederholt Energie aus entsprechenden Prozessen nutzbar zu machen, indem sie reversibel chemische in elektrische Energie umwandeln. Die Leistung von Li-Ionen Batterien hängen sehr stark von den verwendeten Funktionsmaterialien ab. Aktuell verwendete Elektrodenmaterialien haben hohe Produktionskosten, verfügen über limitierte Energiespeichekapazitäten und sind teilweise gefährlich in der Nutzung für größere Bauteile. Dies beschränkt die Anwendungsmöglichkeiten der Technologie insbesondere im Gebiet der hybriden Fahrzeugantriebe. Die vorliegende Dissertation beschreibt bedeutende Fortschritte in der Entwicklung von LiFePO4 als Kathodenmaterial für Li-Ionen Batterien. Mithilfe einfacher Syntheseprozeduren konnten eine vollkommen neue Morphologie (mesokristallines LiFePo4) sowie ein nanostrukturiertes Material mit exzellenten elektrochemischen Eigenschaften hergestellt werden. Die neu entwickelten Verfahren zur Synthese von LiFePo4 sind einschrittig und bei signifikant niedrigeren Temperaturen im Vergleich zu konventionellen Methoden. Die Verwendung von preisgünstigen und umweltfreundlichen Ausgangsstoffen stellt einen grünen Herstellungsweg für die large scale Synthese dar. Mittels des neuen Synthesekonzepts konnte meso- und nanostrukturiertes LiFe PO4 generiert werden. Die Methode ist allerdings auch auf andere phospho-olivin Materialien (LiCoPO4, LiMnPO4) anwendbar. Batterietests der besten Materialien (nanostrukturiertes LiFePO4 mit Kohlenstoffnanobeschichtung) ergeben eine mögliche Energiespeicherung von 94%. KW - Li-Ionen-Akkus KW - Kathode KW - LiFePO4 KW - Mesokristalle KW - Nanopartikel KW - Li-ion batteries KW - cathode KW - LiFePO4 KW - mesocrystals KW - nanoparticles Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-54591 ER - TY - GEN A1 - Busch, Jan Philip A1 - Meißner, Tobias A1 - Potthoff, Annegret A1 - Oswald, Sascha T1 - Plating of nano zero-valent iron (nZVI) on activated carbon : a fast delivery method of iron for source remediation? N2 - The use of nano zerovalent iron (nZVI) for environmental remediation is a promising new technique for in situ remediation. Due to its high surface area and high reactivity, nZVI is able to dechlorinate organic contaminants and render them harmless. Limited mobility, due to fast aggregation and sedimentation of nZVI, limits the capability for source and plume remediation. Carbo-Iron is a newly developed material consisting of activated carbon particles (d50 = 0,8 µm) that are plated with nZVI particles. These particles combine the mobility of activated carbon and the reactivity of nZVI. This paper presents the first results of the transport experiments. N2 - Der Einsatz von elementarem Nanoeisen ist eine vielversprechende Technik zur Sanierung von Altlastenschadensfällen. Aufgrund der hohen Oberfläche und der hohen Reaktivität kannn ZVI chlororganische Schadstoffe dechlorieren und zu harmlosen Substanzen umwandeln. Der Einsatz von Nanoeisen zur Quellen- und Fahnensanierung wird jedoch durch mangelnde Mobilität im Boden im eingeschränkt. Carbo-Iron ist ein neu entwickeltes Material, das aus Aktivkohlepartikeln (d50 = 0,8 µm) und nZVI besteht. Diese Partikel kombinieren die Mobilit ät von Aktivkohle mit der Reaktivität von nZVI. Dieser Artikel beschreibt erste Ergebnisse von Transportuntersuchungen. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 165 KW - Carbo-Iron KW - Nanoeisen KW - nZVI KW - Grundwassersanierung KW - Carbo-Iron KW - nano zero-valent iron KW - nZVI KW - remediation Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-53792 ER -