University of Konstanz
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Decade effects in mental addition
No full textWe examine representational effects of Western numerals on mental arithmetic. An analysis of mental addition tasks using a base-10 place-value notation yields a taxonomy of addition types that is anchored in the notion of complements (i.e. additions with round sums). Two experimental studies use a paradigm of serial addition that presents lists of numbers to adult participants, who mentally represent all intermediate steps. In study 1, participants add sequences of single-digit addends in a self-paced fashion. Study 2 extends this paradigm by simultaneously presenting two addends, thus allowing for a modicum of strategic choice. Both studies vary the number of complements within the lists and measure addition accuracy and latency. Beyond decade and carry effects, our results show that lists containing or enabling complements are easier to add. Addition latencies jointly depend on addition type and problem size. When adders have some discretion about the order of choosing addends, they adaptively exploit the difficulty of addition types by tailoring their sequences to decade boundaries. One motivation for seeking complements lies in enabling subsequent post-complements. Reflecting on the dynamic interplay between numeric representations, strategic choices and cognitive adaptations, we discuss implications for psychological explanations, technology and design.publishe
Sex and age predict habitat selection in the world’s most geographically extensive lion population
No full textConservation of large carnivore populations requires effective management strategies that promote landscape-scale protection and genetic connectivity. Pivotal to the success of these strategies is sufficient evidence, including quantifying the processes that govern species distribution. We used telemetry data from 63 lions from the Kavango-Zambezi Transfrontier Conservation Area (KAZA TFCA) in southern Africa to analyze inter-demographic differences in habitat relationships using a mixed-effects resource selection analysis approach. In this semi-arid landscape, some of the most important drivers of habitat selection are surface water and precipitation, which in turn regulate prey abundance. Predicted relative probability of habitat selection was highest near water irrespective of age and sex; however, the effect of precipitation varied depending on the demographic class. Adult lions and subadult females preferred habitat with above average rainfall; however, the opposite was true for subadult males which showed a strong aversion to precipitation. Across all four demographic classes, relative probability of habitat selection was generally positively associated with higher levels of prey abundance with the exception of gemsbok which was negatively correlated with adult female, subadult male, and subadult female habitat use. The predicted distributions for all four demographic classes were widespread across multiple different land-use types, highlighting the need to extend the traditional concept of formally protected areas to include multi-use landscapes and support large-scale transboundary conservation initiatives.publishe
The Die Is Cast : Decision‐Making Under Risk and Under Ambiguity in Schizophrenia and Alcohol Use Disorder
No full textPatients with schizophrenia (SZ) tend towards riskier decision-making (DM). Yet the specificity of these findings, as well as the impact of impairments in executive functions (EF), has not been sufficiently clarified. In a preregistered study (https:// osf. io/
n7z6y ) 40 SZ, 50 patients with alcohol use disorder (AUD) and 36 healthy controls (HC) completed an n-back task (as EF challenge), the Game of Dice Task (GDT; DM under risk) and the Iowa Gambling Task (IGT; DM under ambiguity). AUD and SZ performed worse than HC in the n-back task and riskier in the GDT. In the IGT, only AUD performed riskier than HC and preferred disadvantageous Deck B compared to SZ. However, controlling for demographics and IQ abolished significance. Correlations of performance in the GDT and IGT with working memory differed between groups. Taken together, both patient groups show a deficit in the reflective system, whereas only AUD show impairments in the impulsive system. Thus, the direct comparison of
DM in SZ and AUD reveals a differential DM profile of SZ and AUD. Our results suggest that both groups may benefit from EF training, especially in planning, categorization and cognitive flexibility, whereas AUD could additionally profit from impulse
control and inhibition training. However, the findings need replication with well-matched samples, and the link between EF and DM in SZ should be examined more carefully with experimental approaches.publishe
Theory of polarization-dependent phonon pumping in ferromagnetic/non-magnetic bilayers
No full textWe develop a theoretical model for polarization-selective phonon pumping induced by magnon–phonon coupling in a ferromagnetic/non-magnetic acoustic bilayer structure, focusing on the effects arising from a misalignment between the magnetic and crystallographic symmetry axes. Our model considers the coupled equations of motion describing uniform magnetization dynamics (the Kittel mode) and elastic waves in both layers, incorporating phonon pumping and boundary conditions at the interface. We show that even small misalignments lift the degeneracy of transverse shear elastic modes, resulting in phononic birefringence characterized by distinct propagation velocities for linearly polarized modes. Furthermore, our analysis reveals that magnon-phonon hybridization gives magnetic-field-dependent properties to otherwise non-magnetic phonons. We show that the polarization transfer between linearly polarized phonons and the circularly polarized Kittel mode can be tuned with an external magnetic field. Our theoretical results quantitatively reproduce recent experimental findings [M. Müller, Phys. Rev. B 109, 024430 (2024)].publishe
Ecological and Social Pressures Influence Diel Activity Patterns in Wild Tibetan Macaques
No full textThe nighttime behavior of diurnal species is a “black box.” Although diurnal animals spend approximately half their lives in the dark, research has, for too long, relied on the simplifying assumption that what we can't observe isn't important. Advances in our ability to monitor nighttime behavior reveal that this is incorrect; essential biological and behavioral processes play out in the dark which are critical for understanding a species' ecology and evolution. We conducted our study from November 2021 to January 2022, using noninvasive 4G solar‐powered night‐vision cameras to quantitatively assess the impact of environmental and social factors on the diel activity patterns of wild Tibetan macaques at Mt. Huangshan, China. We find that Tibetan macaques maintain high levels of sleep throughout the night, as is typical for diurnal animals. However, non‐sleep activity still accounted for 18.28% ± 0.45% of the total nighttime period, with activity occurring throughout the night. Notably, there was a peak in activity at midnight, including resting, movement, and social. Low temperatures significantly reduced daytime activity levels, while increasing nighttime activity, indicating that extreme temperatures have divergent impacts on activity levels during the day versus the night. Additionally, social activities were more frequent among females during the day, whereas males were more socially active at night. The distinct patterns of social activities during the day and night highlight the crucial role of social factors in nocturnal activities. The night‐vision cameras have proven to be an effective research tool, allowing for a deeper understanding of primate behavior patterns and social structures. This provides new avenues for future research into the drivers of nighttime behavioral patterns across species.publishe
Multi-Millennial Genetic Resilience of Baltic Diatom Populations Disturbed in the Past Centuries
No full textLittle is known about the genetic diversity and stability of natural populations over millennial time scales, although the current biodiversity crisis calls for heightened understanding. Marine phytoplankton, the primary producers forming the basis of food webs in the oceans, play a pivotal role in maintaining marine ecosystems health and serve as indicators of environmental change. This study examines the genetic diversity and shifts in allelic composition in the diatom species Skeletonema marinoi over ~8000 years in the Baltic Sea by analyzing chloroplast and mitochondrial genomes. Sedimentary ancient DNA (sedaDNA) demonstrates the stability and resilience of genetic composition and diversity of this species across millennia in the context of major climate events. Accelerated change in allelic composition is observed from historical periods onwards, coinciding with times of intensifying human activity, like the Roman Empire, the Viking Age, and the Hanseatic Age, suggesting that anthropogenic stressors have profoundly impacted this species for the last two millennia. The data indicate a very high natural stability and resilience of the genomic composition of the species and underscore the importance of uncovering genomic disruptions caused by human impact on organisms, even those not directly exploited, to better predict and manage future biodiversity.publishe
A Class of Optimal Control Problems Governed by Caginalp Phase Field Models
No full textCaginalp’s phase field model was introduced to describe phase transition processes such as melting and solidification, but can also be more generally viewed as a model for non-isothermal phase separation processes. Core of the model is the Cahn-Hilliard equation, which was proposed to describe the so-called spinodal decomposition of binary alloys in a rapid cooling process, but can be utilized for phase-separating mixtures in a much broader range.
The goal of this thesis is to set the theoretical framework for a numerical realization of an optimal control problem governed by Caginalp’s phase field model. In particular, this covers the derivation of Caginalp’s model from phase separation phenomena using basic thermodynamics, showing well-posedness of Caginalp’s model and proving the existence of an optimal control as well as deriving a first order necessary optimality condition.publishe
Positive Outcomes of Long-Term Relationship Satisfaction Trajectories in Stable Romantic Couples : A 10-Year Longitudinal Study
No full textGrowing evidence challenges the longstanding assumption of a universal decline in relationship satisfaction for all couples by demonstrating variability in the change. However, knowledge about how differential long-term trajectories of relationship satisfaction are associated with positive individual functioning is lacking. Using dyadic latent class growth analysis, we studied long-term trajectories of relationship satisfaction of N = 300 mixed-gender couples over 10 years and examined positive outcomes in latent subgroups. At the final assessment, partners reported on positive outcomes, specifically affect, mental health, and life satisfaction. Depending on their subgroup membership, couples systematically differed: Couples in the subgroup with high initial and relatively stable relationship satisfaction reported the most favorable outcomes—more positive affect, better mental health, and higher life satisfaction—as compared to subgroups with declining and/or lower relationship satisfaction. The findings show the importance of considering the variability in long-term relationship satisfaction trajectories and point to their relevance for positive functioning.publishe
Filme von Licht im Elektronenmikroskop
No full textMit der Attosekunden‐Elektronenmikroskopie können optische Antworten und elektronische Reaktionsmechanismen in komplexen Materialien direkt in Raum und Zeit gefilmt werden. Wir erreichen dabei simultan eine räumliche Auflösung im Bereich einzelner Nanometer sowie eine Zeitauflösung im Attosekunden‐Bereich, schneller als die Oszillationen von Licht. Die Leistungsfähigkeit dieser Methode demonstrieren wir an einigen nanophotonischen Metamaterialien. Sie ist darüber hinaus zum Beispiel in der Katalysatorforschung oder der Entwicklung neuer elektronischer Schaltkreise anwendbar.publishe