University of Konstanz
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The impact of gettering on LeTID in industrial Czochralski grown gallium-doped p-type silicon ingots with melt recharging
No full textpublishe
Polynomial systems admitting a simultaneous solution
No full textWe provide a description of a complete set of generators for the ideal that serves as the resultant ideal for n univariate polynomials of degree d. Our generators arise as maximal minors of a set of cascading matrices formed from the coefficients of the polynomials, generalizing the classical Sylvester resultant of two polynomials.publishe
Strategic Conformity or Anti-Conformity to Avoid Punishment and Attract Reward
No full textWe provide systematic insights on strategic conformist – as well as anticonformist – behavior in situations where people are evaluated, i.e., where an individual has to be selected for reward (e.g., promotion) or punishment (e.g., layoffs). To affect the probability of being selected, people may attempt to fit in or stand out in order to affect the chances of being noticed or liked by the evaluator. We investigate such strategic incentives for conformity or anticonformity experimentally in three different domains: facts, taste, and creativity. To distinguish conformity and anticonformity from independence, we introduce a new experimental design that allows us to predict participants’ independent choices based on transitivity. We find that the prospect of punishment increases conformity, while the prospect of reward reduces it. Anticonformity emerges in the prospect of reward, but only under specific circumstances. Similarity-based selection (i.e., homophily) is much more important for the evaluators’ decisions than salience. We also employ a theoretical approach to illustrate strategic key mechanisms of our experimental setting.publishe
The effect of traditional agricultural practices on the food consumption of households facing extreme weather events in Tanzania
No full textBackground
An estimated 140 million people in Africa face acute malnutrition. By impacting agricultural production, climate change is likely to further decrease food consumption, particularly in sub-Saharan African states. Against this backdrop, various actors have called for more attention to alternative farming and food systems based on traditional agricultural knowledge capable of ensuring access to sufficient, nutritious, and safe food. So far, however, we have limited systematic evidence on which traditional agricultural practices may promote the food resilience of households exposed to extreme climatic conditions. Focusing on the most prevalent traditional diversification practices in Tanzania, this study assesses the extent to which crop diversification, annual crop intercropping, crop-tree intercropping, crop-livestock integration, and the cultivation of traditional crops increase the food availability and dietary diversity of smallholders facing extreme weather events in Tanzania.
Methods
We combine temperature and rain data with information on farming practices and food consumption information provided by the Living Standards Measurement Study–Integrated Surveys on Agriculture for more than 25,000 Tanzanian households nationwide. We rely on a matched differences-in-differences approach to account for selection bias and allow for causal inference.
Results
Our matching models consistently show that the planting of traditional crops (in particular sorghum) promotes dietary diversity and reduces the need for food rationing in households experiencing climate shocks. In contrast, households relying on maize cultivation show less dietary diversity and increased food rationing behavior. In addition, we find that—under extreme weather conditions—crop diversification furthers households’ dietary diversity, and crop-livestock integration, as well as crop-tree intercropping, seem to reduce households’ need to ration food.
Conclusion and policy recommendation
This study has important implications for policymakers. In light of climate change and weather variability, it underscores the need to better integrate indigenous knowledge into farming systems. Our results call for greater dissemination of traditional diversification strategies and more reliance on indigenous, drought-tolerant crops. Traditional farming practices can function as a safety net, protecting smallholders in Tanzania against the detrimental consequences of weather shocks.publishe
Prevalence and correlates of sexual violence against adolescents : Quantitative evidence from rural and urban communities in South-West Nigeria
No full textDespite the recognized need to address the prevention of sexual violence against adolescents in Nigeria, significant research gaps persist in understanding the patterns, determinants, and impacts of such violence, particularly regarding regional variations and the specific developmental needs of adolescents across different stages. This study provides Nigerian regional prevalence estimates disaggregated by gender, rural/urban, and in/out-of-school populations, while also identifying socio-demographic and cultural determinants related to increased vulnerability. A cross-sectional survey was conducted in South-West Nigeria with a sample of 961 adolescents, targeting in- and out-of-school adolescents aged 13–17 years. Descriptive statistics and logistic regression analyses were performed.The prevalence of any form of SV since age 12 was 69.4%, with higher rates among out-of-school adolescents and boys. Non-contact abuse (63.2%), passive contact abuse (41.9%), and active contact abuse (28.7%) were the most common forms reported. Peers were the dominant perpetrators (77.1%), followed by other adults (27.9%). Being male (OR 2.033), older (OR 1.214 per year), involved in a romantic relationship (OR 2.731), and experiencing SV before age 12 (OR 4.622) were significant risk factors. Higher household wealth (OR 0.902 per asset) and emotional support from both parents (OR 0.413) were protective factors.This study highlights the high burden of SV against adolescents in Nigeria, with concerning patterns of male victimization and peer perpetration. The findings emphasize the need for comprehensive, evidence-based strategies addressing emotional support, social norms, power dynamics, and economic vulnerabilities to prevent and respond to this problem effectively.publishe
Non‐canonical C16 Homoterpene Biosynthesis Widespread in Actinobacteria
No full textA novel biosynthetic pathway towards the rare and underexplored non‐canonical family of homoterpenes was discovered in actinobacteria through targeted genome mining and enzymatic in vitro reconstitution. The pathway comprises initial methylation‐induced double bond isomerization of farnesyl diphosphate (FPP) to (2E,7E)‐6‐methyl‐farnesyl diphosphate, catalyzed by a novel family of methyltransferases with unique dual function. The resulting linear C16 double bond isomer of FPP constitutes the specific substrate for a distinct family of type I terpene cyclases, catalyzing diverse cyclization reactions. Functional characterization of nine enzyme pairs led to discovery of five unprecedented homoterpene natural products. The enzymological novelty enable the development of novel biocatalytic and genetically programmable synthetic strategies towards methylated terpenoids with potentially unique properties (“magic methyl effect”).publishe
Influence of melatonin on the successful infection of Daphnia dentifera by Metschnikowia bicuspidata
No full textThe levels of the hormone melatonin fluctuate daily, with higher concentrations often found at night. These fluctuations likely influence multiple aspects of physiology, including the immune response. We demonstrated that the addition of exogenous melatonin increased the proportion of the freshwater zooplankton Daphnia dentifera that became infected by the fungal pathogen Metschnikowia bicuspidata, during the day but not at night. To determine the stage of this host–pathogen interaction at which melatonin may increase susceptibility, we conducted a series of laboratory experiments in which we raised Daphnia in the presence and absence of exogenous melatonin. To complete its life cycle, Metschnikowia must encounter a foraging host, overcome the host's barrier resistance (gut wall), and evade the host's immune response (internal clearance). We quantified encounter rate by measuring the gut passage time and the number of spores that entered the gut. We also measured the number of spores that successfully entered the body cavity (barrier resistance) and the hemocyte response to spores entering the body cavity (one metric of internal clearance). Finally, we quantified the effect of exogenous melatonin on triggering molting. The addition of exogenous melatonin lengthened gut passage time and decreased the number of spores present in the gut. We found no effect of melatonin on the percentage of gut spores successfully entering the host's body cavity, nor on the hemocyte response. Melatonin is known to influence the timing of molting and hosts that molted during exposure were more likely to become infected, likely due to a decrease in barrier resistance. In a fully factorial experiment, there was a high death rate, low infection rate, and therefore no discernible effect of melatonin on molting, nor molting or melatonin on infection. Our results provide insight into the stages of infection where melatonin does and does not have significant effects.publishe
A case‐by‐case analysis of EPN and LPP components within a “one‐picture‐per‐emotion‐category” protocol
No full textStimuli encountered in the environment are continuously evaluated according to their affective stimulus significance. Numerous event‐related potential studies have shown that the early posterior negativity (EPN) and the late positive potential (LPP) are larger for high than low arousing emotional pictures. The group approach has been recently extended to the study of the individual case. Usually, many exemplars are used to represent an emotion category. Determining how many pictures are needed to reliably assess affective stimulus evaluation processes at the individual level is crucial when moving toward the goal of exploring idiosyncratic emotional stimuli. Accordingly, in the present study ( N = 16), singular images displaying erotic, neutral, and mutilation content were shown 800 times while dense sensor EEG was recorded. At the group level, enhanced EPN and LPP amplitudes for high compared to low arousing stimuli emerged. At the single subject level, significantly larger amplitudes to the erotic than neutral image were observed in 15 out of 16 tests for the EPN and LPP components. Regarding the mutilation image, 15 participants showed a significant EPN effect, while the LPP effect was only found in 10 cases. Notably, emotional modulation of the EPN and LPP was stable over time. The present study contributes to the development of experimental designs tailored to the needs of the case‐by‐case approach. Since the process of affective stimulus evaluation is considered as a process common‐to‐all, the use of a singular stimulus exemplar may prove useful to investigate the idiosyncratic nature of emotion.publishe
Granularity for Mixed-Integer Polynomial Optimization Problems
No full textFinding good feasible points is crucial in mixed-integer programming. For this purpose we combine a sufficient condition for consistency, called granularity, with the moment-/sum-of-squares-hierarchy from polynomial optimization. If the mixed-integer problem is granular, we obtain feasible points by solving continuous polynomial problems and rounding their optimal points. The moment-/sum-of-squares-hierarchy is hereby used to solve those continuous polynomial problems, which generalizes known methods from the literature. Numerical examples from the MINLPLib illustrate our approach.publishe
Nostalgia, Trauma, Retrofuturism : reframing history in serial Neo-Historical TV drama
No full textExpanding on a variety of cross-disciplinary theoretical frameworks and discourses around historiography, historical fiction, television studies, seriality, and narrative complexity, the dissertation asks questions about the modes, functions, and effects of contemporary televisual historical fictions:
How do the inherent contingencies of the medium television at the brink of ‘Peak TV’ impact the telling of stories set in the past? How do televisual historical fictions employ their serial structure — the narrative possibilities afforded by long-form storytelling, repetition with variation, and vast potential for reflexiveness and recursivity to narrativize pastness? What role can and does narrative complexity with its accompanying features play in this endeavor? And what effect(s) does this have on the concrete ontological and epistemological underpinnings of historical representation in a popular, (post-)postmodern medium and cultural context? When and how are viewers’ preconceived notions of ‘History’ and historical categories like objectivity and singular truth undermined or disrupted rather than affirmed and reproduced?
In exploring these questions, I identify a mode of ‘doing history’ (see Rosenstone, “The Future of the Past” 202) in TV series of this era that can be identified as neo-historical in its reframing of the past. Reframing established, reductive notions of history itself, neo-historical fictions self-reflexively “critique, conceptualize, engage with, and reject the processes of representation and narrativization” (De Groot, Remaking History 2). They actuate the affordances of contemporary serial storytelling on TV — including practices of repetition with variation and narrative accumulation — without working against their own comprehensibility. Eschewing deconstruction and dissolution of narrative cohesion and historical meaning, they instead retain narrative coherence and a level of watchability that is essential for their own continued existence in a popular commercial medium. Generically and tonally hybrid, they reflect on issues of time and temporality more subtly than historiographic metafictions and their focus on denarrativization and rejection of historical truths and representation altogether. Narratives engaging in this neo-historical mode are conscious of the problematic ontologies of their endeavor of historical narrativization, yet they acknowledge and pursue the value inherent in the process. The TV series discussed as case studies in this dissertation (Man Men, Peaky Blinders, Halt and Catch Fire) are therefore self-aware of their inadequacies and continue, serially, to explore them, becoming more complex in the process. It is the central thesis of this dissertation that the neo-historical, in its oscillation between realism and meta-fictionality, coherence and confusion, novelty and tradition, subversion and creation of historical narrative(s) — in short: serial ambiguity — finds an ideal form and mode in the serial narrative complexity of contemporary (longform) television drama.publishe