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Amazonian aerosol size distributions in a lognormal phase space: characteristics and trajectories
No full textThis study introduces a first glance at Amazonian aerosols in the N–Dg–σ phase space. Aerosol data, measured from May 2021 to April 2022 at the Amazon Tall Tower Observatory (ATTO), were fitted by a multi-modal lognormal function and separated into three modes: the sub-50 nm, the Aitken (50–100 nm), and the accumulation modes. The fit results were then evaluated in the N–Dg–σ phase space, which represents a three-dimensional space based on the three lognormal fit parameters. These parameters represent, for a given mode i, the number concentration (Ni), the median geometric diameter (Dg,i), and the geometric standard deviation (σi). Each state of a particle number size distribution (PNSD) is represented by a single dot in this space, while a collection of dots shows the delimitation of all PNSD states under given conditions. The connections in ensembles of data points show trajectories caused by pseudo-forces, such as precipitation regimes and vertical movement. We showed that all three modes have a preferential arrangement in this space, reflecting their intrinsic behaviors in the atmosphere. These arrangements were interpreted as volumetric figures, elucidating the boundaries of each mode. Time trajectories in seasonal and diurnal cycles revealed that fits with the sub-20 nm mode are associated with rainfall events that happen in the morning and in the afternoon. But in the morning they grow rapidly into the Aitken mode, and in the afternoon they remain below 50 nm. Also, certain modes demonstrated well-defined curves in the space, e.g., the seasonal trajectory of the accumulation mode follows an ellipsoid, while the diurnal cycle of the sub-50 nm mode in the dry season follows a linear trajectory. As an effect of the precipitation on the PNSDs and vice versa, N and Dg were found to increase for the sub-50 nm mode and to decrease for the Aitken and accumulation modes after the precipitation peak. Afternoons with precipitation were preceded by mornings with larger particles of the accumulation mode, whose Dg was ∼ 10 nm larger than in days without precipitation. Nevertheless, this large Dg in the morning seems to influence subsequent rainfall only in the dry season, while in the wet season both N and Dg seem to have the same weight of influence. The observed patterns of the PNSDs in the N–Dg–σ phase space showed to be a promising tool for the characterization of atmospheric aerosols, to contribute to our understanding of the main processes in aerosol–cloud interactions, and to open new perspectives on aerosol parameterizations and model validation
Influence of Silver Fiber Morphology on the Dose–Response Relationship and Enrichment in Daphnia magna Studied by Elemental Imaging with LA-ICP-TOF-MS
No full textThis study aims to enhance the understanding of the environmental risks associated with nanomaterials, particularly nanofibers. Previous research suggested that silver fibers exhibit higher toxicity (EC50/48h 1.6–8.5 μg/L) compared to spherical silver particles (EC50/48h 43 μg/L). To investigate the hypothesis that toxicity is influenced by the morphology and size of nanomaterials, various silver nanofibers with different dimensions (length and diameter) were selected. The study assessed their toxicity toward Daphnia magna using the 48 h immobilization assay. The EC50 values for the different fibers ranged from 122 to 614 μg/L. Subsequently, the study quantified the uptake and distribution of two representative nanofibers in D. magna neonates by employing digestion and imaging mass spectrometry in the form of laser-ablation-ICP-MS. A novel sample preparation method was utilized, allowing the analysis of whole, intact daphnids, which facilitated the localization of silver material and prevented artifacts. The results revealed that, despite the similar ecotoxicity of the silver fibers, the amount of silver associated with the neonates differed by a factor of 2–3. However, both types of nanofibers were primarily found in the gut of the organisms. In conclusion, the findings of this study do not support the expectation that the morphology or size of silver materials affect their toxicity to D. magna
Social complexity shapes signal production and complexity in wild chimpanzees and sooty mangabeys
No full textAnimal social systems are diverse ranging from largely solitary to highly gregarious and cooperative. Signalling plays a major role in the negotiation of social cohesion, coordination and the formation and maintenance of social relationships. Social complexity is hypothesised to be a contributing factor in the evolution and expansion of cognitive and communicative skills across species. However, empirical tests evaluating the relative impact of different aspects of social complexity on communication systems are challenging to conduct, especially in comparative research where ecological and phylogenetic factors may confound the social elements of interest. Here, I examined the impact of social complexity on signalling patterns using within and between-species comparisons in four sympatric groups of two terrestrial primate species: Western chimpanzees (Pan troglodytes verus) and sooty mangabeys (Cercocebus atys atys) from the Taï forest, Ivory Coast. Both species form large multimale, multifemale groups. Mangabeys form matrilineal societies, with an important role of kinship in the patterning of relationships. Chimpanzees cooperate extensively with non-kin group members, and show strong fission-fusion dynamics, generating highly unpredictable social environments and varying social cohesion needs between group members. I examined signalling probability and complexity during social approaches, using behavioural data I collected during focal follows on mature individuals. I classed complex signals as combined (with several signal types) or multisensory signals (combining visual and auditory modalities) because they contain more elements than unisensory or single signalling. These complex signals may increase message efficacy or reduce message ambiguity and thus may be particularly valuable during high-stake situations, such as contexts with high coordination needs or social uncertainty. Chapter 2 determines that contexts with high coordination needs, feeding, and particularly travelling, markedly increased combined signalling probability compared with resting in chimpanzees but not mangabeys. Further, the production of combined and socio-positive signals during approaches predicted longer periods of dyadic association in chimpanzees. Chapter 3 evaluates that in both species, post-conflict contexts with a former opponent promoted the production of both multisensory and combined signals during approaches. Further, in chimpanzees, events of fusion, inter-party communication and post-conflict with a third party were strongly associated with an increase in signalling probability and complexity, but not in mangabeys. Chapter 4 demonstrates that high socio-positive signalling reciprocity reflected close relationships, but only clearly in chimpanzees. Further, both species had well-differentiated relationships, but chimpanzees had generally more grooming partners and a lower level of differentiation between dyads, which may explain a higher number of dyads with reciprocal signalling compared with mangabeys. Both within and between-species findings offer support for the hypothesis that social complexity contributed to the selection of high signalling flexibility, complexity, and reciprocity. This thesis provides evidence that societies with strong fission-fusion dynamics and the presence of close non-kin relationships promote signal production and complexity. Specifically, complex signalling facilitates social cohesion and relationship maintenance, particularly when facing high social uncertainty or coordination challenges between partners
Bilder als Irritationsmomente beim kulturbezogenen Lernen - eine empirische Studie zu ägyptischen Deutschlernenden
No full textDie vorliegende Arbeit widmet sich der Frage, inwieweit mehrdeutige Bilder mit kulturellem Potenzial eine Rolle in kulturbezogenen Lernprozessen spielen können. Die Annahme ist, dass Bilder mit multiplen Interpretationsmöglichkeiten ein hohes Potenzial für das kulturbezogene Lernen besitzen, da sie Lernende dazu anregen können, ihre Gefühle und Emotionen verstärkt zum Ausdruck zu bringen. Theoretisch verankert wird die Untersuchung in Ingeborg Schüßlers Konzept des Deutungslernens, Rolf Arnolds Ansatz des Emotionslernens sowie der Theorie des expansiven Lernens von Klaus Holzkamp mitsamt seiner subjekttheoretischen Perspektive. Darüber hinaus stützt sich diese Forschung auf den kulturwissenschaftlichen Ansatz der Landeskunde von Claus Altmayer, der „Kultur“ nicht mehr als objektiv definiertes Konstrukt, sondern als Aushandlung von Bedeutungen begreift. Ziel der empirischen Studie mit ägyptischen Deutsch-als-Fremdsprache-Lernenden ist es, Antworten auf folgende Fragestellungen zu generieren: Inwieweit können mehrdeutige Bilder mit kulturellem Potenzial den kulturbezogenen Lernprozess initiieren? Welches Potenzial weisen solche Bilder auf den verschiedenen Ebenen innerhalb von kulturbezogenen Lernprozessen auf?:Inhaltsverzeichnis
1. Einleitung 1
2. Theoretischer Rahmen 6
2.1 Stand der Forschung 12
2.2 Zum Begriff „kulturbezogenes Lernen“ 24
2.2.1 Subjektive und soziale Dimensionen des Lernens 26
2.2.2 Emotionen und soziale Interaktion im Lernprozess 28
2.2.3 Irritation als zentrale Dimension des kulturbezogenen Lernens 30
2.2.4 Didaktische Umsetzung und empirische Forschung 31
2.3 Irritation und Irritationsmomente 32
3. Verwendung von Bildern als visuelle Medien im DaF-Unterricht 44
3.1 Bilder im kulturbezogenen Lernkontext: Eine kulturwissenschaftliche Perspektive auf Visual Culture und nicht-essentialistische Kulturbegriffe 49
3.2 Potenziale und Herausforderungen des Einsatzes von Bildern im kulturbezogenen Lernprozess 54
3.3 Einsatz von mehrdeutigen Bildern zum Aufbau und Initiieren des kulturbezogenen Lernprozesses 57
3.4 Bilder als Irritationsmomente 67
3.5 Situiertes und kontextualisiertes Lernen mit mehrdeutigen Bildern: Auswirkungen auf die Anwendbarkeit von Wissen und die emotionale Wirkung im Unterricht 70
3.6 Reflexion und Ableitungen: Die Rolle von Bildern im kulturbezogenen Lernen und Implikationen für die empirische Untersuchung 73
3.7 Schlussfolgerung 76
4. Methodische Vorgehensweise 78
4.1 Aufbau der empirischen Untersuchung 78
4.2 Datenerhebung 85
4.2.1 Erster Teil der Datenerhebung (Fallstudie) 86
4.2.2 Zweiter Teil der Datenerhebung 102
4.2.3 Auswertungsbogen zum Workshop 113
4.3 Datenaufbereitung 113
4.4 Methodenauswahl 115
5. Datenanalyse und Auswertung 129
5.1. Erster Untersuchungsteil 129
5.1.1 Auswertung/Datenanalyse der Fragebögen mit den Lehrern 129
5.1.2 Datenanalyse der unstrukturierten Interviews mit den Lehrern 131
5.1.3 Analyse der schriftlichen Bildbeschreibung der Lernenden 139
5.1.4 Analyse der Gruppendiskussion mit den Lernenden 152
5.1.5 Auswertung des schriftlichen Feedbacks nach der Diskussion 167
5.2 Zweiter Untersuchungsteil 175
5.2.1 Auswertung des Workshops: Auswahl der Unterrichtssequenzen 175
5.2.2 Sequenzanalyse 176
6. Ergebnisse 349
6.1 Ergebnisse des ersten Teils 349
6.2 Ergebnisse des zweiten Teils 351
6.3 Antwort auf die Forschungsfragen 360
6.4 Implikationen für die Praxis 375
6.5 Selbstreflexion: Die Rolle des Forschenden im Kontext des Workshops 377
7. Fazit und Ausblick 383
8. Literatur 386
Tabellenverzeichnis
Tabelle 1: Hierarchische Darstellung der methodischen Schritte der empirischen Untersuchung 80
Tabelle 2: Unterschiedliche Interpretationen von den DaF-Lehrenden zum gezeigten Bild 139
Tabelle 3: Unterschiedliche Interpretationen von den DaF-Lernenden zum gezeigten Bild 167
Abbildungsverzeichnis
Abbildung 1: Aufbau und Initiieren kulturbezogener Lernprozesse 58
Abbildung 2: Integratives, zyklisches Modell des umfassenden kulturbezogenen Lernprozesses 363Abstract
This study explores the extent to which ambiguous images with cultural potential can play a role in culture-related learning processes. The hypothesis assumes that images with multiple interpretation possibilities have high potential for cultural learning, as they can encourage learners to express their feelings and emotions more intensely.
The study is theoretically grounded in Ingeborg Schüßler’s concept of 'interpretative learning', Rolf Arnold’s approach to 'emotional learning' and Klaus Holzkamp’s 'theory of expansive learning' along with his subject-theoretical perspective. Furthermore, this research draws on Claus Altmayer’s cultural studies approach to 'Landeskunde', which no longer views 'culture' as an objectively defined construct but rather as a negotiation of meanings.
The aim of the empirical study, conducted with Egyptian learners of German as a foreign language, is to answer the following questions:
- To what extent can ambiguous images with cultural potential initiate the culture-related learning process?
- What potential do such images have at different levels within culture-related learning processes?:Inhaltsverzeichnis
1. Einleitung 1
2. Theoretischer Rahmen 6
2.1 Stand der Forschung 12
2.2 Zum Begriff „kulturbezogenes Lernen“ 24
2.2.1 Subjektive und soziale Dimensionen des Lernens 26
2.2.2 Emotionen und soziale Interaktion im Lernprozess 28
2.2.3 Irritation als zentrale Dimension des kulturbezogenen Lernens 30
2.2.4 Didaktische Umsetzung und empirische Forschung 31
2.3 Irritation und Irritationsmomente 32
3. Verwendung von Bildern als visuelle Medien im DaF-Unterricht 44
3.1 Bilder im kulturbezogenen Lernkontext: Eine kulturwissenschaftliche Perspektive auf Visual Culture und nicht-essentialistische Kulturbegriffe 49
3.2 Potenziale und Herausforderungen des Einsatzes von Bildern im kulturbezogenen Lernprozess 54
3.3 Einsatz von mehrdeutigen Bildern zum Aufbau und Initiieren des kulturbezogenen Lernprozesses 57
3.4 Bilder als Irritationsmomente 67
3.5 Situiertes und kontextualisiertes Lernen mit mehrdeutigen Bildern: Auswirkungen auf die Anwendbarkeit von Wissen und die emotionale Wirkung im Unterricht 70
3.6 Reflexion und Ableitungen: Die Rolle von Bildern im kulturbezogenen Lernen und Implikationen für die empirische Untersuchung 73
3.7 Schlussfolgerung 76
4. Methodische Vorgehensweise 78
4.1 Aufbau der empirischen Untersuchung 78
4.2 Datenerhebung 85
4.2.1 Erster Teil der Datenerhebung (Fallstudie) 86
4.2.2 Zweiter Teil der Datenerhebung 102
4.2.3 Auswertungsbogen zum Workshop 113
4.3 Datenaufbereitung 113
4.4 Methodenauswahl 115
5. Datenanalyse und Auswertung 129
5.1. Erster Untersuchungsteil 129
5.1.1 Auswertung/Datenanalyse der Fragebögen mit den Lehrern 129
5.1.2 Datenanalyse der unstrukturierten Interviews mit den Lehrern 131
5.1.3 Analyse der schriftlichen Bildbeschreibung der Lernenden 139
5.1.4 Analyse der Gruppendiskussion mit den Lernenden 152
5.1.5 Auswertung des schriftlichen Feedbacks nach der Diskussion 167
5.2 Zweiter Untersuchungsteil 175
5.2.1 Auswertung des Workshops: Auswahl der Unterrichtssequenzen 175
5.2.2 Sequenzanalyse 176
6. Ergebnisse 349
6.1 Ergebnisse des ersten Teils 349
6.2 Ergebnisse des zweiten Teils 351
6.3 Antwort auf die Forschungsfragen 360
6.4 Implikationen für die Praxis 375
6.5 Selbstreflexion: Die Rolle des Forschenden im Kontext des Workshops 377
7. Fazit und Ausblick 383
8. Literatur 386
Tabellenverzeichnis
Tabelle 1: Hierarchische Darstellung der methodischen Schritte der empirischen Untersuchung 80
Tabelle 2: Unterschiedliche Interpretationen von den DaF-Lehrenden zum gezeigten Bild 139
Tabelle 3: Unterschiedliche Interpretationen von den DaF-Lernenden zum gezeigten Bild 167
Abbildungsverzeichnis
Abbildung 1: Aufbau und Initiieren kulturbezogener Lernprozesse 58
Abbildung 2: Integratives, zyklisches Modell des umfassenden kulturbezogenen Lernprozesses 36
Microborings reveal alternating agitation, resting and sleeping stages of modern marine ooids
No full textOoids are abundant carbonate grains throughout much of Earth’s history, but
their formation is not well understood. Here, an in-depth study of microbial
bioerosion features of Holocene ooids from the Schooner Cays ooid shoals
(Great Bahama Bank, Eleuthera, Bahamas) and the Shalil al Ud ooid shoals
in the Arabian/Persian Gulf (Abu Dhabi, United Arab Emirates) is presented.
No obvious differences were found in ooid size distribution, cortex layer
thickness, the composition of nuclei or euendolithic community when com-
paring ooids from both locations. Microendolithic borings are present in
most studied ooid surfaces, but the intensity of (micro-)bioerosion varies sig-
nificantly. Applying an epoxy vacuum cast-embedding technique allowed
the identification of ichnotaxa and their inferred producers (various genera
of diatoms, cyanobacteria, coccolithophores and unspecified bacteria). Euen-
dolithic taxa have specific low-light tolerances and light optima. This
implies that information about the relative bathymetry (seafloor versus burial
within an ooid shoal) and ecology for ooid cortex formation can be obtained
via the presence or absence of their respective ichnotaxa. The history of a
statistically significant number of ooid cortices can be translated into dune
dynamics and the temporal variations thereof by allocating the inferred
index producer to a defined burial or light penetration zone. In this context,
ooid formation can be divided into four stages: (i) an agitation stage in the
water column, characterized by the colonization of grains by photoauto-
trophs; (ii) a resting stage, characterized by temporary burial of the ooid,
leading to immobilization and a shift towards heterotrophs; (iii) a sleeping
stage, characterized by prolonged burial and colonization by organotrophs; and (iv) a reactivation stage, characterized by a resurfacing of the ooid and a
subsequent shift towards photoautotrophs. The sleeping stage is presumably
a stage of ooid degradation where bioerosion, mainly by heterotrophic fungi
and bacteria is particularly active
Subgrid-scale variability of cloud ice in the ICON-AES 1.3.00
No full textThis paper presents a stochastic approach for the aggregation process rate in the ICOsahedral Nonhydrostatic general circulation model (ICON-AES), which takes subgrid-scale variability into account. This method creates a stochastic parameterization of the process rate by choosing a new specific cloud ice mass at random from a uniform distribution function. This distribution, which is consistent with the model's cloud cover scheme, is evaluated in terms of cloud ice mass variance with a combined satellite retrieval product (DARDAR) from the satellite cloud radar CloudSat and the Cloud–Aerosol Lidar and Infrared Pathfinder Observations (CALIPSO). The global patterns of simulated and observed cloud ice mixing ratio variance are in a good agreement, despite an underestimation in the tropical regions, especially at lower altitudes, and an overestimation in higher latitudes from the modeled variance. Due to this stochastic approach the yearly mean of cloud ice shows an overall decrease. As a result of the nonlinear nature of the aggregation process, the yearly mean of the process rates increases when taking subgrid-scale variability into account. An increased process rate leads to a stronger transformation of cloud ice into snow and therefore to a cloud ice loss. The yearly averaged global mean aggregation rate is more than 20 % higher at selected pressure levels due to the stochastic approach. A strong interaction of aggregation and accretion, however, lowers the effect of cloud ice loss due to a higher aggregation rate. The new stochastic method presented lowers the bias of the aggregation rate
Sophisticated Study of Time, Frequency and Statistical Analysis for Gradient-Switching-Induced Potentials during MR
No full textMagnetic resonance imaging (MRI) is a standard procedure in medical imaging, on a
par with echography and tomodensitometry. In contrast to radiological procedures, no harmful
radiation is produced. The constant development of magnetic resonance imaging (MRI) techniques
has enabled the production of higher resolution images. The switching of magnetic field gradients
for MRI imaging generates induced voltages that strongly interfere with the electrophysiological
signals (EPs) collected simultaneously. When the bandwidth of the collection amplifiers is higher
than 150 Hz, these induced voltages are difficult to eliminate. Understanding the behavior of these
artefacts contributes to the development of new digital processing tools for better quality EPs. In this
paper, we present a study of induced voltages collected in vitro using a device (350 Hz bandwidth).
The experiments were conducted on a 1.5T MRI machine with two MRI sequences (fast spin echo
(FSE) and cine gradient echo (CINE)) and three slice orientations. The recorded induced voltages
were then segmented into extract patterns called “artefact puffs”. Two analysis series, “global” and
“local”, were then performed. The study found that the temporal and frequency characteristics were
specific to the sequences and orientations of the slice and that, despite the pseudo-periodic character
of the artefacts, the variabilities within the same recording were significant. These evolutions were
confirmed by two stationarity tests: the Kwiatkowski–Phillips–Schmidt–Shin (KPSS) and the time-
frequency approach. The induced potentials, all stationary at the global scale, are no longer stationary
at the local scale, which is an important issue in the design of optimal filters adapted to reduce MRI
artifacts contaminating a large bandwidth, which varies between 0 and 500 Hz
Investigating motor system adaptations of an exergame training in older adults
No full textWith advancing age, molecular and cellular damage accumulates (Kirkwood, 2011; Kirkwood & Austad, 2000), resulting in gradual impairments across the entire motor system (Seidler et al., 2010). These age-related changes lead to declines in both motor (Muehlbauer et al., 2015; Rosano et al., 2012) and cognitive performance (Hedden & Gabrieli, 2004). Additionally, studies have shown that as individuals age, motor tasks require greater attention and additional cognitive resources (Li & Lindenberger, 2002; Schaefer, 2014).
Physical activity holds great potential for preventing the decline of motor and cognitive abilities and mitigating age-related neural degeneration (Bherer et al., 2013). Furthermore, research has demonstrated that multimodal or combined training approaches, integrating physical, motor, and cognitive components are more effective in improving cognition than traditional single-mode training programs (Rahe et al., 2015). In this context, the novelty and complexity of the exercises employed during training are critical factors influencing effectiveness (Fissler et al., 2013).
Both complexity and novelty are fundamental characteristics of movement-based video games, known as exergames, which engage players in physical activity while simultaneously providing cognitive stimulation within a highly dynamic gaming environment. This variability in learning experiences is essential for the transfer of skills to other novel tasks (Fissler et al., 2013; Green & Bavelier, 2008). However, there is currently limited understanding of the potential benefits of exergaming for (fine) motor skills (Jorgensen et al., 2013; Maillot et al., 2012; Nitz et al., 2010) and potential structural brain changes related to these activities (Ji et al., 2017; O'Callaghan et al., 2018).
To expand the current knowledge on the effects of exergaming on the motor system of older adults, we conducted two studies using a two-group pre-post test design. Healthy, right-handed participants aged 65 years and older, who did not take central-acting medications, were included. To eliminate any potential influence of physical or musical expertise on our behavioural and structural brain measures, we excluded highly skilled musicians, typists, and athletes from both studies. Participants were randomly assigned in each study to either an intervention group (IG), which underwent exergame training (2 sessions per week, 60 minutes each), or a passive control group (CG), which received no specific interventions. Additionally, participants in the CG were instructed to maintain their usual lifestyle.
The primary objective of Study 1 was to investigate the effect of a short-term exergame training program lasting 6 weeks on (fine) motor and cognitive performance, as well as the transfer to untrained skills. Building on this, the primary objective of Study 2 was to examine the structural adaptations in grey matter (GM) and white matter (WM) resulting from exergame training and to determine how these adaptations correlate with physical, (fine) motor, and cognitive abilities in older adults. Additionally, Study 2 aimed to explore the temporal progression of motor and cognitive adaptations. Consequently, the training duration was extended to 11 weeks, with behavioural measurements taken at three time points (pre, after 6 weeks, and after 11 weeks).
To investigate between-group effects, a change score for each time point (Study 1: 6 weeks, Study 2: 6 and 11 weeks) relative to baseline (pre-test) was calculated and compared using Mann-Whitney U tests for two independent samples. The level of statistical significance was set at α<.05, with Bonferroni correction applied to account for multiple comparisons. Statistical analyses of behavioural data were performed using RStudio 1.2.5033 (RStudio Team, 2020). To ensure comparability between both studies, similar statistical testings of the behavioural outcomes were used. To examine structural brain changes (Study 2), a full factorial model was employed with group as the between-subjects factor. For GM analysis, adjustments were made for age, sex, and total intracranial volume. Statistical significance was determined using a voxel threshold of p<.001 and a family-wise error corrected cluster threshold of p<.05. In the analysis of WM, adjustments were made for age and sex. To account for multiple comparisons, threshold-free cluster enhancement was applied along with a family-wise error rate cluster threshold of p<.05. Statistical analyses for GM were conducted using SPM12, while analyses for WM were performed using FSL.
In both studies, the IG exhibited significant improvements in fine motor skills of the left hand compared to the CG. Additionally, in Study 2, notable enhancements were observed in left-hand grip strength and complex whole-body reaction time. These behavioural improvements were most prominent following the first 6 weeks of exergame training. Although both studies demonstrated significant practice effects from exergaming, neither study indicated broad improvements in motor and cognitive abilities for the IG after 6 weeks (Study 1 and Study 2) or after 11 weeks (Study 2).
Furthermore, contrary to our expectations, no significant structural changes were observed in either grey or white matter. Even exploratory analyses utilizing an uncorrected significance level (p<.001) did not reveal any changes in WM. For GM, a cluster was detected in the temporal lobe of the IG. Furthermore, no significant correlations were found between changes in grey or white matter and changes in behavioural measures.
The significant improvements in fine motor skills of the left hand found after 6 weeks of training in Study 1 were confirmed in Study. Additionally, in Study 2, the IG showed increased left-hand grip strength and improved choice step reaction time (CSRT) compared to the CG after 6 weeks. These findings of enhanced upper body strength contribute to the existing literature on exergaming, while the observed improvements in CSRT are consistent with previous research (Hauer et al., 2020; Okubo et al., 2017). However, no broad improvements in (fine) motor, physical, or cognitive abilities were found in either study after 6 or 11 weeks. The absence of generalized behavioural changes may be attributed to the temporal dynamics of the exergame training effects, with substantial practice effects observed in the first 6 weeks, followed by minimal further gains between 6 and 11 weeks.
This lack of general behavioural improvements may also be related to the null findings in the MRI results, as enhanced motor performance through physical training is typically associated with brain plasticity (Lehmann, Villringer, & Taubert, 2020; Taubert et al., 2011). It is possible that the physical and/or cognitive stimulation provided by the exergame was insufficient to stimulate the release of BDNF, a neurotrophic factor crucial for synaptic function (Lu et al., 2013) and the regulation of myelinogenesis (Du et al., 2003), thereby failing to induce structural changes in the brain (Anderson-Hanley et al., 2018; Reycraft et al., 2020). Additionally, the sample size in both studies—although slightly larger in Study 2—may have substantially impacted the statistical power of the current findings. Combined with the necessity for corrections for multiple comparisons, this could have increased the likelihood of false-negative results.
Overall, the findings of this thesis indicate that exergame training can enhance health-related abilities in older adults, including fine motor skills, upper body strength, and CSRT. Consequently, exergaming has the potential to improve the functional capabilities of this population, aligning with the World Health Organization's definition of healthy aging (WHO, 2015). Future research should prioritize two key areas: 1) investigating the broader transfer effects of exergaming on daily life improvements for older adults, and 2) examining the underlying mechanisms, such as the physical and cognitive load associated with these activities. Furthermore, longitudinal studies are needed to assess both functional and structural brain adaptations, including laboratory measures (e.g., BDNF, lactate), to enhance our understanding of the neuronal mechanisms affected by exergaming.:1 Introduction 1
2 The aging motor system 3
2. 1 Motor performance deficits in older adults 3
2. 2 Measuring the aging brain 5
2. 3 Neural plasticity in the aging brain 7
3 Training interventions to counteract age-related changes of the
motor system 9
3. 1 Traditional training interventions 10
3. 1. 1 Metabolic physical exercises 10
3. 1. 2 Gross motor training 12
3. 2 Enriched training environments 13
3. 2. 1 Dancing and Tai Chi 14
3. 2. 2 Video games 15
3. 2. 2. 1 Sedentary video games 15
3. 2. 2. 2 Exergames 18
4 Scope of the experimental work 21
5 Experimental work 22
5. 1 Study 1 – Behavioural effects of a short-term exergame training in
older adults: a preliminary investigation 22
5. 1. 1 Scope of the study 22
5. 1. 2 Material and methods 23
5. 1. 3 Results 36
5. 1. 4 Discussion 41
5. 1. 5 Supplementary materials 49
5. 2 Study 2 – Effects of exergaming on sensorimotor performance and
brain structure in older adults 55
5. 2. 1 Scope of the study 55
5. 2. 2 Material and methods 57
5. 2. 3 Results 71
5. 2. 4 Discussion 81
5. 2. 5 Supplementary materials 98
6 General discussion 104
7 Summary of the dissertation 111
8 References 116
9 Appendix 181
9. 1 Author’s contribution to the publications 181
9. 2 Declaration of authenticity 182
9. 3 Curriculum Vitae 183
9. 4 Publications 185
9.5 Acknowledgments 18
The big four of plant taxonomy: a comparison of global checklists of vascular plant names
No full textThis article is part of the Special Collection ‘Global plant diversity and distribution’. See https://www.newphytologist.org/global-plant-diversity for more details
Multi-section reference value for the analysis of horizontally scanning aerosol lidar observations
No full textThe quantitative analysis of measurements with
horizontally scanning aerosol lidar instruments faces two
major challenges: the background correction can be affected
by abnormal signal peaks, and the choice of a reference ex-
tinction coefficient αref is complicated if aerosols are ubiq-
uitous in the sampled volume. Here, we present the newly
developed multi-section method for the stable solution of ex-
tinction coefficient retrievals from horizontally scanning li-
dar measurements. The algorithm removes irregular peaks
related to signal noise based on an experimentally derived
fitting model. A representative value for αref is inferred from
converging retrievals along different scan axes and over mul-
tiple scans of 10 to 15 min under the assumption that they
are only related to ambient aerosols without distinct emis-
sion sources. Consequently, αref obtained through the multi-
section method reflects typical atmospheric aerosols unaf-
fected by emissions and noise. When comparing αref to the
PM2.5 mass concentrations at national monitoring stations
near the measurement area, a significant correlation with an
r2 value exceeding 0.74 was observed. The presented case
studies show that the new method allows for the retrieval
and visualization of spatio-temporal aerosol distributions and
subsequent products such as PM2.5 concentrations