University of Konstanz
KOPS - The Institutional Repository of the University of KonstanzNot a member yet
31050 research outputs found
Sort by
Environmental change and migration aspirations : Evidence from Bangladesh
No full textThe argument that environmental stress is an important driver of migration has gained renewed attention amidst increasing climatic changes. This study examines whether and how two distinct environmental stressors influence migration aspirations among affected populations. Our analysis relies on two waves of original survey data of 1,594 households residing in 36 villages along the 250 km of the Jamuna River in Bangladesh, an area heavily impacted by floods and riverbank erosion. The results reveal that riverbank erosion – a long-term environmental event causing permanent destruction – increases aspirations for internal, permanent migration by about 15 percentage points, 4 to 6 months after the occurrence. In contrast, sudden and short-term events, like floods, which have a more temporary impact, do not affect migration aspirations. These results suggest that the type of environmental event shapes adaptation strategies, with migration emerging as a viable response to more severe and lasting events such as erosion. This entails important policy implications regarding the effects of climate change on future patterns of internal migration and highlights that most affected individuals prefer to adapt to environmental stress in situ or within close proximity.publishe
Editorial: Multisystem inflammatory syndrome observed post-COVID-19: the role of natural products, medicinal plants and nutrients and the use of prediction tools supporting traditional forms of diagnosis
No full textpublishe
Reduced avoidance behaviour in Daphnia magna due to agrochemical-induced vulnerability
No full textThe continuous discharge of agrochemicals used in intensive agriculture contaminates aquatic systems, harming aquatic biota and their processes. Although mobile organisms can avoid continuous exposure by moving to less-affected habitats, their capacity can be altered by pollutant exposure. Populations with a previous disturbance history, which show a lower ability to respond to subsequent stressors, are defined as vulnerable. Therefore, this study investigated the so far unknown escape capacity of a vulnerable zooplankton population previously exposed to a contaminated environment. To this end, agrochemically driven vulnerability was induced in populations of Daphnia magna by exposure to sublethal concentrations of glyphosate. Vulnerability was verified using a starvation test in which significant differences were observed between the control populations and populations with a disturbance history. Both the Control and Vulnerable populations were assessed for their avoidance capacity by exposing them to a glyphosate gradient using a Heterogeneous Multiple-Habitat Assay System (HeMHAS). The control populations showed a rapid reaction from the beginning of the assay, with avoidance rates increasing over 24 h, while vulnerable populations were unable to avoid contaminated habitats for up to 24 h. Therefore, we concluded that vulnerable populations have a lower capacity to avoid contaminated habitats. In heterogeneously contaminated habitats, a lower avoidance capacity is responsible for the differential spatial distribution of the affected species, which impacts the ecosystem structure. Additionally, agrochemically induced vulnerability and its effect on avoidance behaviour may affect ecosystem functioning through the altered spatial distribution of zooplankton populations.publishe
Well-posedness of solutions for multi-d hyperbolized compressible Navier-Stokes equations
No full textA hyperbolized compressible Navier-Stokes system is considered in multi dimensions, where the parts of the stress tensor are fully relaxed. Local existence is obtained first, then global solutions for small data, with estimates being uniform in the three relaxation parameters, the latter allowing the prove a weak convergence result to the classical compressible Navier-Stokes system, globally in time, as the relaxation parameters tend to zero. Finally, a blow-up result for large data is proved.submitte
Animal social networks are robust to changing association definitions
No full textThe interconnecting links between individuals in an animal social network are often defined by discrete, directed behaviours, but where these are difficult to observe, a network link (edge) may instead be defined by individuals sharing a space at the same time, which can then be used to infer a social association. The method by which these associations are defined should be informed by the biological significance of edges, and therefore often vary between studies. Identifying an appropriate measure of association remains a challenge to behavioural ecologists. Here, we use automatically recorded feeder visit data from four bird systems to compare three methods to identify a social association: (1) strict time-window, (2) co-occurrence in a group, and (3) arrival-time. We tested the similarity of the resulting networks by comparing the repeatability and sensitivity of individuals’ social traits (network degree, strength, betweenness). We found that networks constructed using different methods but applying similar, ecologically relevant definitions of associations based on individuals’ spatio-temporal co-occurrence, showed similar characteristics. Our findings suggest that the different methods to construct animal social networks are comparable, but result in subtle differences driven by species biology and feeder design. We urge researchers to carefully evaluate the ecological context of their study systems when making methodological decisions. Specifically, researchers in ecology and evolution should carefully consider the biological relevance of an edge in animal social networks, and the implications of adopting different definitions.publishe
When do prevocational programs ease the transition to vocational education and training?
No full textPreparing youth for the transition from school to work is a key labor market challenge in many countries. Across Europe, there are many educational pograms to improve youth’s school-to-work transitions. In Germany, youth with difficulties in their school-to-work transitions are channeled into prevocational programs to help them to enter vocational education and training (VET), which serve as an entry into the labor market. Using data drawn from the National Educational Panel Study (NEPS; N = 1,282 participants of prevocational programs), we (1) examined youth’s transition trajectories after their attendance of a first prevocational program and (2) how using institutional resources such as internships during the first prevocational program supports youth’s transitions to VET. Our findings of sequence and cluster analysis showed that approximately two-thirds of the participants had largely stable transitions to VET (i.e., transitions with a low risk of dropout), although many of these transitions were delayed by one year after leaving their first prevocational program. In contrast, one-third of the participants had at-risk transition trajectories and were at risk of being permanently excluded from the education and employment system. By conducting a multinomial logistic regression, we also found that attending long internships and attaining a higher school certificate during the first prevocational program was associated with a smooth transition to VET programs, and both factors “protected” youth from encountering difficult pathways with very low prospects of reaching VET programs after leaving prevocational programs. Moreover, mentoring during prevocational programs and the perceived degree to which the programs helped youth to form occupational aspirations were also associated with a lower probability of facing at-risk transition trajectories.publishe
Increasing the smoking cessation success rate by enhancing improvement of self-control through sleep-amplified memory consolidation : protocol of a randomized controlled, functional magnetic resonance study
No full textBackground: Tobacco use disorder (TUD) remains a global health crisis characterized by high relapse rates despite extensive cessation efforts. This study aims to enhance treatment outcomes by addressing the cognitive and neural imbalances associated with habitual and goal-directed behaviours among individuals with TUD. We hypothesise that by integrating high-intensity interval training (HIIT), cognitive remediation treatment (CRT) via app-based chess training and a standard smoking cessation program (SCP) for cognitive control and sleep quality will be improved, thereby facilitating smoking cessation.
Methods: The study will enrol 140 treatment-seeking smokers aged 18–65 years who meet the DSM-5 criteria for TUD. The participants will be randomly assigned to four groups: CRT + HIIT in the morning, CRT + HIIT in the evening, HIIT alone in the morning, and HIIT alone in the evening. Assessments will be conducted at baseline (T1), postintervention (T2), and at a three-month follow-up (T3) at the Central Institute of Mental Health in Mannheim, Germany. The primary outcomes include abstinence days or amount of alcohol consumed in cases of relapse, as well as craving reduction. Secondary outcomes include improvements in cognitive functions (working memory, response inhibition, and cognitive control), measured through neuropsychological tasks, functional magnetic resonance imaging (fMRI), polysomnography, and self-report questionnaires. The repeated-measures design allows for within-subject comparisons to evaluate intervention effectiveness.
Discussion: This study aims to provide insights into the mechanisms through which combined CRT and evening HIIT, alongside improvements in sleep quality, can enhance smoking cessation outcomes. The hypothesised benefits on cognitive control and neural activity changes are expected to support better treatment adherence and reduced relapse rates among individuals with TUD. Addressing potential challenges such as high dropout rates through comprehensive participant support is crucial for the study’s success. Findings from this research could inform future therapeutic strategies for TUD, potentially advancing addiction treatment approaches. The integration of novel interventions with established cessation programs underscores the study’s significance in exploring holistic approaches to improving public health outcomes related to tobacco addiction.
Trial registration: Registered at clinicaltrials.gov/ct2/show/NCT05726045 (Date 04.04.2024).publishe
Are you safe or should I go? : How perceived trustworthiness and probability of a sexual transmittable infection impact activation of the salience network
No full textFunctional imaging studies indicate that both the assessment of a person as untrustworthy as well as the assumption that a person has a sexually transmitted infection are associated with activation in regions of the salience network. However, studies are missing that combine these aspects and investigate the perceived trustworthiness of individuals previously assessed with high or low probability of a sexually transmitted infection.
During fMRI measurements, 25 participants viewed photographs of people pre-classified as having high or low HIV probability and judged their trustworthiness. In a post-rating, stimuli were rated for trustworthiness, attractiveness and HIV probability.
Persons pre-classified as HIV- in contrast to those pre-classified as HIV+ were rated more trustworthy and with lower HIV probability. Activation in medial orbitofrontal cortex was higher for those rated and pre-classified as HIV- than HIV+. Based on the individual ratings, but not the pre-classification, there was significantly higher activation in Insula, amygdala, anterior cingulate cortex and Nucleus accumbens in response to untrustworthy than to trustworthy faces.
Activation of the salience network occurred when a person was judged as untrustworthy, but not according to a pre-classification. Activation in the medial orbitofrontal cortex, a structure associated with reward was enhanced when a person was perceived as trustworthy, and also when a person was pre-classified with low HIV probability. Our findings suggest that trustworthiness and HIV- perception have consistency across samples, while the perception of risk and associated activation of the salience network has restricted cross-sample consistency.
Significance Statement: Whether a person is trustworthy or might pose a risk to one’s own health must be decided in a few moments and based on limited characteristics. The salience network as an “alarm system” should be involved in these evaluative processes. This paper reports the results of neural activation in trustworthiness judgments of naturalistic stimuli of persons pre-categorized as HIV+ or HIV-. We find activation in medial orbitofrontal cortex for people evaluated as trustworthy and for people pre-categorized as HIV-. For people judged as untrustworthy, activation in insula, amygdala, anterior cingulate cortex and Nucleus accumbens is revealed. These findings suggest a safety signal in the medial orbitofrontal cortex and an involvement of the salience network in risk detection.publishe
Nonmonotonic Motion of Sliding Droplets on Strained Soft Solids
No full textSoft materials are ubiquitous in technological applications that require deformability, for instance, in flexible, water-repellent coatings. However, the wetting properties of prestrained soft materials are only beginning to be explored. Here we study the sliding dynamics of droplets on prestrained soft silicone gels, both in tension and in compression. Intriguingly, in compression we find a nonmonotonic strain dependence of the sliding speed: mild compressions decelerate the droplets, but stronger compressions lead again to faster droplet motion. Upon further compression, creases nucleate under the droplets until, finally, the entire surface undergoes the creasing instability, causing a “run-and-stop” motion. We quantitatively elucidate the speed modification for moderate prestrains by incremental viscoelasticity, while the acceleration for larger prestrains turns out to be linked to the solid pressure, presumably through a lubrication effect of expelled oligomers.publishe