Universität Konstanz
  • Konstanz, Germany
Recent publications
Spatially resolved transcriptomics is an emerging class of high-throughput technologies that enable biologists to systematically investigate the expression of genes along with spatial information. Upon data acquisition, one major hurdle is the subsequent interpretation and visualization of the datasets acquired. To address this challenge, VR-Cardiomics is presented, which is a novel data visualization system with interactive functionalities designed to help biologists interpret spatially resolved transcriptomic datasets. By implementing the system in two separate immersive environments, fish tank virtual reality (FTVR) and head-mounted display virtual reality (HMD-VR), biologists can interact with the data in novel ways not previously possible, such as visually exploring the gene expression patterns of an organ, and comparing genes based on their 3D expression profiles. Further, a biologist-driven use-case is presented, in which immersive environments facilitate biologists to explore and compare the heart expression profiles of different genes.
Against the background of digital transformation processes that are currently changing the world of work, this paper examines general digital competences of beginning trainees in commercial vocational education and training (VET) programs. We are particularly interested in factors influencing digital competence profiles. From survey data including N = 480 trainees in one federal state in Germany, we were able to identify three different competence profiles (based on the trainees’ self-assessment of their general digital competence). Initial descriptive analysis reveals differences between competence profiles of different training professions (industrial clerks and retail salespersons reach higher competence levels than salespersons). However, regression results indicate that these differences can be explained by differences in school leaving certificates. Contrary to prior empirical evidence, we find no significant effect of trainees’ gender. Finally, the frequency of certain private digital activities (e.g. using office programs, conducting internet searches) affects digital competence profiles. Implications for both VET programs and further research are discussed.
This paper contributes to the literature on social stratification by analysing the role of internal migration as a possible channel for the intergenerational transmission of inequality. While internal migration is associated with social mobility, it can also be used as a strategy of status maintenance among graduates from privileged backgrounds. The aim of this paper is to scrutinize whether internal migration for study or work, and subsequent labour market outcomes, are associated with social origins. Using a rich administrative and survey data set on a cohort of Italian graduates, findings show a substantive effect of social origins on graduates’ migration for study but not on migration for work. Finally, the results also more tentatively indicate that migration for study is one relevant path connecting social origins and income, thus emphasizing how privilege is not bound to place, but travels.
The modern, over 250-m-deep basin of Lake Constance represents the underfilled northern part of an over 400-m-deep, glacially overdeepened trough, which reaches well into the Alps at its southern end. The overdeepening was formed by repeated glacial advance-retreat cycles of the Rhine Glacier throughout the Middle to Late Pleistocene. A seismic survey of Lake Constance revealed a Quaternary sediment fill of more than 150 m thickness representing at least the last glacial cycle. The stratified sedimentary fill consists at the base of ice-contact deposits on top of the molasse bedrock, overlain by glaciolacustrine to lacustrine sediments. During the successful field test of a newly developed, mid-size coring system ("HIPERCORIG"), the longest core (HIBO19) ever taken in Lake Constance was retrieved with an overall length of 24 m. The sediments recovered consist of a nearly continuous succession of lacustrine silts and sands including more than 12 m of Late Glacial sediment at the base. 14 lithotypes were identified through petrophysical and geochemical analyses. In combination with a ¹⁴ C- and OSL-based age-depth model, the core was divided into three main chronostratigraphic units. The basal age of ~ 13.7 ka BP dates the base of the succession back to the Bølling-Allerød interstadial, with overlying strata representing a complete and thick Younger-Dryas to Holocene succession. The sediments offer a high-resolution insight into the evolution of paleo-Lake Constance from a cold, postglacial to a more productive and warmer Holocene lake. The Late Glacial succession is dominated by massive, m-thick sand beds reflecting episodic sedimentation pulses. They are most likely linked to a subaquatic channel system originating in the river Seefelder Aach, which is, despite the Holocene drape, still apparent in today’s lake bathymetry. The overlying Holocene succession reveals a prominent, several cm-thick, double-turbiditic event layer representing the most distal impact of the Flimser Bergsturz, the largest known rockslide of the Alps that occurred over 100 km upstream the river Rhine at ~ 9.5 ka BP. Furthermore, lithologic variations in the Holocene succession document the varying sediment loads of the river Rhine and the endogenic production representing a multitude of environmental changes.
China’s involvement in African countries has been criticized for being guided by self-interest rather than recipient need or merit. For the period 2000–2012, we compare China’s aid allocation behaviour to that of the five largest donor countries globally: France, Germany, Japan, the UK, and the USA. We use regression analysis and a rigorous variance decomposition method to measure the importance of various factors in predicting aid commitments. We find that donors differ markedly in how they allocate aid. While Germany, Japan, the USA, and the UK assign high importance to recipient need, France’s and China’s allocation models are, for a large part, driven by variables that relate to self-interest: trade in the case of France, and the adherence to the “One-China policy” in the case of China. However, China is not a purely selfish donor. As most Western donors, China commits more aid to poorer countries. Furthermore, we find no evidence that commercial interests, such as trade or access to natural resources, determine Chinese aid allocation. This latter result contrasts with Western donors, which allocate more aid to their trade partners. France and the UK also commit significantly more aid to their former colonies. In conclusion, the claim that China’s aid allocation is different must be qualified.
We investigate the formation of singularities in one-dimensional hyperbolic compressible Navier-Stokes equations, a model proposing a relaxation leading to a hyperbolization through a nonlinear Cattaneo law for heat conduction as well as through the constitutive Maxwell type relations for the stress tensor. By using the entropy dissipation inequality, which gives the lower energy estimates of the local solutions without any smallness condition on initial data, and by constructing some useful averaged quantities we show that there are in general no global C1 solutions for the studied system with some large initial data. This appears as a remarkable contrast to the situation without relaxation, i.e. for the classical compressible Navier-Stokes equations, where global large solutions exist. It also contrasts the fact that for the linearized system associated to the classical resp. relaxed compressible Navier-Stokes equations, the qualitative behavior is exactly the same: exponential stability in bounded domains and polynomial decay without loss of regularity for the Cauchy problem.
We study how groups reach consensus by varying communication network structure and individual incentives. In 342 networks of seven individuals, single opinionated “leaders” can drive decision outcomes, but do not accelerate consensus formation, whereas conflicting opinions slow consensus. While networks with more links reach consensus faster, this advantage disappears under conflict. Unopinionated individuals make choices consistent with a local majority rule combined with “inertia” favouring their previous choice, while opinionated individuals favour their preferred option but yield under high peer or time pressure. Simulations show these individual rules can account for group patterns, and allow rapid consensus while preventing deadlocks.
We offer experimental evidence for the effect of social sampling on redistributive preferences through a survey experiment using a probabilistic national sample in Germany. We primed respondents to think about different types of social contacts, in particular low- and high-income contacts. We find evidence for an indirect effect in which the priming task shapes preferences for redistribution through its effect on the respondents' estimates of their contacts' incomes. Respondents in the low-income (high-income) priming recalled social contacts with lower (higher) incomes, which in turn predict more (less) support for redistributive policies. The indirect effect of the low-income (high-income) priming is stronger among high-income (low-income) respondents, suggesting that our priming task elicited the social contacts whom the respondents, given their own incomes, are less likely to recall. We discuss the implications of these findings to our understanding of how social sampling shapes redistributive preferences as well as relates to social networks and ideology.
Alternative methods to animal use in toxicology are evolving with new advanced tools and multilevel approaches, to answer from one side to 3Rs requirements, and on the other side offering relevant and valid tests for drugs and chemicals, considering also their combination in test strategies, for a proper risk assessment. While stand-alone methods, have demonstrated to be applicable for some specific toxicological predictions with some limitations, the new strategy for the application of New Approach Methods (NAM), to solve complex toxicological endpoints is addressed by Integrated Approaches for Testing and Assessment (IATA), aka Integrated Testing Strategies (ITS) or Defined Approaches for Testing and Assessment (DA). The central challenge of evidence integration is shared with the needs of risk assessment and systematic reviews of an evidence-based Toxicology. Increasingly, machine learning (aka Artificial Intelligence, AI) lends itself to integrate diverse evidence streams. In this article, we give an overview of the state of the art of alternative methods and IATA in toxicology for regulatory use for various hazards, outlining future orientation and perspectives. We call on leveraging the synergies of integrated approaches and evidence integration from in vivo, in vitro and in silico as true in vivitrosi.
Previous research has found that oxytocin (OT) is associated with intergroup behaviour in humans as well as wild chimpanzees, and that exogenous OT affects Pan social attention. The two Pan species, bonobos and chimpanzees, differ drastically from one another in their intensity of intergroup competition, with lethal intergroup aggression often led by males in chimpanzees and more tolerant associations often centered around females in bonobos. However, it remains unclear how exogenous OT changes the two species' responses to ingroup and outgroup individuals. In this study, after intranasal administration of nebulized OT or placebo control, chimpanzees and bonobos viewed image pairs of ingroup and outgroup conspecifics while their eye movements were tracked with an eye-tracker. Although the overall effect of OT was small, we found that OT shifted bonobos' and chimpanzees' attention to outgroup images of the sex primarily involved in intergroup encounters in each species. Specifically, OT selectively shifted attention towards outgroup photos of female conspecifics in bonobos, and those of outgroup male conspecifics in chimpanzees. This suggests that OT generally promotes outgroup attention in both bonobos and chimpanzees but this effect is restricted to the sex most relevant in intergroup relations. These results suggest that, although OT may have a generally conserved role in hominid intergroup behaviour, it may act in species-relevant ways under the influence of their socio-ecological backgrounds.
We investigate cheating in work groups, to empirically test the idea of an honest workplace environment as a determinant of performance. Three individuals receive team-based performance pay for executing a real-effort task. In addition, two of them have the opportunity to obtain a bonus in a dice game, which allows cheating without exposure by misreporting a secret die roll. We are particularly interested in the behavioral response of the bystander as the potential witness to the dishonest action. To identify the implications of lies at work, the rules of the bonus game were altered to randomly prevent cheating, or not, across treatment conditions while holding the monetary consequences constant. Survey data enables us to analyze effect heterogeneity and to explore mechanisms underlying behavioral responses. We begin our analysis by estimating the mean lying rate and find that the opportunity-to-cheat is exploited in roughly 42% of cases. The probability of misreporting increases if the cheater's partner in crime is male. Contrary to claims on the importance of honesty at work, we do not observe a reduction in performance when cheating takes place, neither for the bystander nor for the whole team. Bounded awareness could be an explanation, as we find substantial evidence for effect heterogeneity along the lines of information preferences. Bystanders with higher preferences for inconvenient information provide relatively low task performance, compared to those with lower information preferences, who seem to turn a blind eye to the dishonest action of their co-workers by putting increased effort into their work.
Several factors affect periphyton biomass by acting at local and landscape levels simultaneously. Thereunder, we quantified local and land-use variables in a gradient of subtropical streams at the transboundary border between Brazil and Paraguay to determine the influence of some factors (morphology, water dynamics, nutrients, light availability, land use, and number of agrochemicals) on periphyton biomass. We sampled 24 streams (12 in Brazil and 12 in Paraguay) in three different moments (February, July, and November 2019). Biomass was proxied by chlorophyll-a and ash-free dry mass. We also estimated the autotrophic index of periphytic communities as the ratio between ash-free dry mass and chlorophyll-a values. We found that periphyton biomass was structured mainly by stream morphology, water dynamics , and the number of agrochemicals (pesticides) present in the water. Surprisingly, we also found that light availability influenced biomass to a smaller extent, whereas nutrients did not exhibit a significant effect. Our results highlight the influence of stream morphology, water dynamics, and agrochemicals on aquatic biota, demonstrating the importance of conservation of local and regional environments to support the primary productivity and ecosystem functions in streams.
Theoretical physics predicts optimal information processing in living systems near transitions (or pseudo-critical points) in their collective dynamics. However, focusing on potential benefits of proximity to a critical point, such as maximal sensitivity to perturbations and fast dissemination of information, commonly disregards possible costs of criticality in the noisy, dynamic environmental contexts of biological systems. Here, we find that startle cascades in fish schools are subcritical (not maximally responsive to environmental cues) and that distance to criticality decreases when perceived risk increases. Considering individuals' costs related to two detection error types, associated to both true and false alarms, we argue that being subcritical, and modulating distance to criticality, can be understood as managing a trade-off between sensitivity and robustness according to the riskiness and noisiness of the environment. Our work emphasizes the need for an individual-based and context-dependent perspective on criticality and collective information processing and motivates future questions about the evolutionary forces that brought about a particular trade-off.
Humans have translocated thousands of species, either intentionally or not, from their native ranges to non-native ones, with many established (naturalized) and some now invasive. We report here a global database on the distributions of naturalized alien insects. Currently, 7,741 naturalized alien insect species have been reported from 222 regions, of which 47 species were reported over all six continents, 103 species over five continents, and 208 species over four continents. Naturalized alien insects are taxonomically diverse in all six continents, predominantly occurring in agroecosystems, as well as forests and grasslands. North America has accumulated the greatest number of naturalized alien insect species, while South America has the lowest number. Asia donated the greatest number of its native insect species to other continents, especially to North America and Europe. The global patterns of naturalized alien insects are correlated with transcontinental trade and the number of local scientists who study insect invasions. Most naturalized alien insects have been introduced to multiple continents, further facilitating the expansion of introduced populations through bridgehead effects. Understanding the global exchange and accumulation of alien insects helps the development of an early warning and monitoring system for insect invasions.
The present study assessed the hypothesis that electrophysiological markers of emotional and task stimulus significance can be demonstrated in concert at the level of the individual case. Participants (n = 18, 9 females) viewed low and high-arousing pictures selected from behavior systems of sexual reproduction, disease avoidance, and predator fear. Furthermore, to concurrently manipulate task relevance, participants performed an explicit emotion categorization task with either low or high-arousing pictures alternating as target stimuli in separate experimental blocks. Pooled across behavior systems, event-related components sensitive to emotional significance reached statistical significance in 100% of the tests for the early posterior negativity and in 96% of the tests for the late positive potential. Regarding explicit task relevance, the target P3 effect was significant in 96% of the tests. These findings demonstrate that neural markers of stimulus significance driven by emotional picture content and explicit task demands can be assessed at the individual level. Replicating an effect case-after-case provides strong support for an effect common-to-all and may support individual inferences. Contributions of the case-by-case approach to reveal reproducible effects and implications for the development of neural biomarkers for specific affective and cognitive component processes are discussed.
Indirect evolutionary rescue (IER) is a mechanism where a non-evolving species is saved from extinction in an otherwise lethal environment by evolution in an interacting species. This process has been described in a predator-prey model, where extinction of the predator is prevented by a shift in the frequency of defended towards undefended prey when reduced predator densities lower selection for defended prey. We test here how increased mortality and the initial frequencies of the prey types affect IER. Combining the analysis of model simulations and experiments with rotifers feeding on algae we show IER in the presence of increased predator mortality. We found that IER was dependent on the ability of the prey to evolve as well as on the frequency of the defended prey. High initial frequencies of defended prey resulted in predator extinction despite the possibility for prey evolution, as the increase in undefended prey was delayed too much to allow predator rescue. This frequency dependency for IER was more pronounced for higher predator mortalities. Our findings can help informing the development of conservation and management strategies that consider evolutionary responses in communities to environmental changes.
The ability of hydrogen quantification in crystalline silicon in concentrations as low as [Formula: see text] becomes fairly important in regard to hydrogen-related degradation phenomena in silicon devices generally and solar cells particularly. The method presented here allows for direct boron–hydrogen pair quantification and, therefore, allows inference on total hydrogen content. Hydrogen-rich amorphous silicon nitride was deposited on stripes of boron-doped float-zone silicon (1 [Formula: see text]), which were exposed to a rapid high temperature step to introduce relatively high amounts of hydrogen into the wafer. Infrared absorption spectra, which have been corrected for multiple reflection and free-carrier absorption, show absorption related to the boron–hydrogen stretching mode at [Formula: see text] with varying strengths during formation and subsequent dissociation of boron–hydrogen pairs triggered by annealing in the dark at [Formula: see text]. Since the measurements were performed at room temperature, this method allows investigations with little effort and standard laboratory equipment. Furthermore, the change in free-carrier absorption (described by Drude’s theory) is used to derive the change in hole concentration concurring with the formation and dissociation of boron–hydrogen pairs. The latter is found to fairly match not only the changing strength in absorption of the stretching mode, but also the change in hole concentration obtained by highly sensitive resistivity measurements. The comparison of stretching mode absorption strength and change in resistivity allows for a calibration of specific absorption, yielding a calibration factor [Formula: see text]. This calibration was performed with the absorption [Formula: see text] [[Formula: see text]] as well as with the quotient of absorption and wavenumber [Formula: see text] [[Formula: see text]].
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4,411 members
Christoph Kleineidam
  • Department of Biology
Bernd Genser
  • Department of Economics
Werner Reichmann
  • Department of History and Sociology
Susumu Shikano
  • Department of Politics and Public Administration
Wanja Wolff
  • Department of Sports Science
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Konstanz, Germany
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www.uni-konstanz.de