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Xanthophyll cycling and fucoxanthin biosynthesis in the model diatom Phaeodactylum tricornutum : recent advances and new gene functions
No full textDiatoms, heterokont microalgae found in all aquatic habitats, can be distinguished by their typical brown colour due to the presence of a characteristic light-harvesting carotenoid: fucoxanthin. The biosynthesis of fucoxanthin involves several intermediates, some of which also play a key role in photoprotection via the xanthophyll cycle, controlling the dissipation of excessively absorbed light energy in the form of Non-Photochemical Quenching (NPQ). The regulation of the fucoxanthin pathway is therefore crucial to direct xanthophyll biosynthesis towards light harvesting or photoprotective functions. Yet, until recent years most of the steps in this key metabolical route remained unknown. Interestingly, diatoms possess multiple homologs of the ancestral genes encoding the two xanthophyll cycle enzymes: Violaxanthin De-Epoxidase (VDE) and Zeaxanthin Epoxidase (ZEP). Here, we review the recent discoveries of the function of most VDE and ZEP isoforms in the fucoxanthin pathway of the model diatom Phaeodactylum tricornutum . Some of these enzymes have a central role in photoprotection, while other have been identified as ideal targets for engineering and industrial applications. We discuss the physiological role of these proteins and address missing links in the pathway and unknown properties of these enzymes. Finally, we argue that the expansion of the VDE and ZEP gene families represented a turning point in the evolution of xanthophyll cycling and fucoxanthin biosynthesis in diatoms.publishe
Voting in the shadow of Russian aggression : Evidence from the Parliamentary Assembly of the Council of Europe 2012–2016
No full textThe Parliamentary Assembly of the Council of Europe (PACE) is not just the oldest but also the most institutionalised and powerful international parliamentary assembly. As transnational parliamentary body with the Russian Federation and Ukraine among its members, it showcases a laboratory for transnational parliamentary voting behaviour in the context of international geopolitical conflicts. We theorise how geopolitical aggression between member states change the voting pattern in the assembly. Whereas we generally assume a partisan cleavage as the main sorting mechanism, we theorise that this dimension will diminish under geopolitical threat. To test our claims, we explore voting patterns in the PACE around the Russian annexation of Crimea 2014. Using all contested votes from 2012 to 2016, we find that voting positions are structured around national interests in times of geopolitical tensions whereas a left-right cleavage emerges once the aggressor (i.e. Russia) was absent from the PACE.publishe
Who perceives lower wages for women to be fair? : How perceptions of the fairness of men’s and women’s wages vary by firm and workplace characteristics
No full textPrevious research has shown that gender pay gaps are perceived as fair or justified, not only by men but also by women. In this paper we contribute to the discussion of a biased evaluation of fair wages and assess whether the organizational context has an impact on fairness perceptions. We use unique data from a vignette study that was part of a representative online survey of 5,556 employees in 532 larger firms (> 100 employees) in Germany which are merged to administrative data. This allows us to consider different contextual factors at both the workgroup level and the firm level. In contrast to older studies we find that women tend to evaluate wages of female workers as unfairly too low. Moreover, the perception of (un)fair wages depends on the organizational context. Female supervisors and collective bargaining agreements in firms increase the likelihood that female employees evaluate other women’s wages as unfairly low. When employees talk about their wages with their colleagues, they are more likely to judge the wages of co-workers as unfairly low.publishe
Experience and motivation shape the flight performance of white storks migrating long-distance
No full textMovement allows animals to access resources and pursue fitness. Yet, this requires balancing movement costs against other potential benefits. These trade-offs can change over lifetimes, as optimality is contextual and depends on ability and need. For migratory soaring birds, efficient movement requires exploiting atmospheric uplift— a challenging task that negates the cost of flight. Due to this link between costs and the environment, soaring birds are limited in when and where they fly. Thus, soaring performance goes beyond movement skills and also involves coping with potentially imperfect conditions to reduce time or competition. Here, we asked whether, over repeated migrations, white storks (Ciconia ciconia) improve their ability to soar. Using high-resolution lifetime tracking data from 151 storks, we found that juveniles outperformed adults under supportive conditions, but, with age, migration difficulty increased and adults performed well under challenging conditions. Adults traveled in less-supportive conditions and spent more energy on flight, indicating a change in ability and motivation. Thus, understanding how animals improve is not simply described by a learning curve but requires a multifaceted perspective on individual needs and skills.publishe
Brief non-spatial signals facilitate visual search and temporal sensitivity in robot supervision
No full textThe human role in human–swarm interaction (HSI) shifts from controller to supervisor, as robots become more autonomous and require efficient search strategies in complex visual environments. Previous research has shown that spatially uninformative brief cues enhance search performance in laboratory environments (namely, “pip-and-pop” effect). Here we examined if these effects can be effectively applicable in HSI. To this end, we conducted two experiments using small mobile robots (Thymio II) to investigate the impact of auditory, tactile, and audiotactile cues on visual search performance and timing judgments. In the first experiment, 20 participants identified a stopped robot among moving robots. The results showed that all cue conditions significantly reduced reaction times (RTs) compared to the no-cue condition, suggesting that brief spatially non-informative signals improve search performance by increasing sensory information accumulation speed. The second experiment involved 12 participants judging the duration of a robot’s stop after a tactile cue was presented or not. The findings indicate that tactile cues improve temporal sensitivity without affecting subjective duration judgments. These results highlight the potential of uni- and multisensory cues to enhance HSI performance by facilitating quicker and more accurate human responses, particularly in dynamic environments. The study extends the “pip-and-pop” effect to real-world scenarios, offering insights for designing HSI systems that allow users to interact with robotic swarms more naturally and efficiently.publishe
Meta-Reflexivität in der Lehrerinnen- und Lehrerbildung
No full textMeta-Reflexivität nutzt das Professionalisierungspotenzial von Differenz zwischen Elementen in der Lehrpersonenbildung. Theorien, empirische Befunde oder Komponenten werden als je spezifische und zu relationierende Beiträge zur Professionalisierung verstanden. Die jeweiligen Eigenlogiken können offengelegt und so Referenzpunkte für situative Deutungen und professionelles Handeln geschaffen werden. Aktuelle Entwicklungen werden skizziert.publishe
Rule them all! : Party leaders, intra-partisan coordination and representation
No full textThis dissertation explores how party leaders strategically manage intra-party coordination and how, in doing so, they impact the quality of political representation. Drawing on a theoretical framework that views parties as arenas where leaders and Members of Parliament (MPs) exchange resources, I argue that discipline does not simply arise from ideological agreement or a vertical chain of command. Instead, it is the outcome of a continuous negotiation in which both actors’ preferences and their political capital play a central role. MPs leverage their individual capital to gain concessions from leaders who, in turn, strategically distribute party-controlled resources (such as committee positions, speaking opportunities, or campaign support). By conceptualizing these interactions as a modified Tullock contest, the dissertation formalizes how disparities in political capital shape the balance between maintaining party cohesion and accommodating heterogeneous constituencies, thereby affecting whose voices are amplified or silenced in politics.
Conceptually, this dissertation highlights the normative trade-off between cohesion and representation faced by parties. Understanding how this trade-off is resolved requires considering three key variables: the strength of a party's leader, the intra-partisan distribution of preferences, and the intra-partisan distribution of political capital. Depending on these, parties choose solutions located between hyper-cohesion (hollowed-out representation) and hyper-representation (fragmented parties), which suggests that the best quality of representation is reached when party leaders enjoy moderate strength. The salience of this trade-off and the horizon of possible solutions are profoundly impacted by institutional settings (electoral systems and parliamentary rules), which affect both the heterogeneity of preferences supposedly represented by a party and the nature and quantity of a leader's leverage over their MPs. Beyond the institutional aspect, unknown distributive forces also affect how political capital is created and distributed across political actors, which further shapes the trade-off solutions available to parties. Empirical analyses comparing German and British representatives crucially confirm the key role played by political capital. Not only does this dissertation nuance our understanding of the spatial logic of intra-partisan coordination, it also highlights the central role played by political capital. This latter concept has been neglected in contemporary literature, and the present dissertation calls for reinstating its place in the study of parliaments, parties, and more generally democratic representation.publishe
Metabolic state shapes cortisol reactivity to acute stress : A systematic review and meta-analysis of metabolic and hormonal modulators
No full textIndividual variability in cortisol stress responses is shaped by multiple physiological factors. Yet the interaction with metabolic and hormonal states remains poorly understood. Therefore, we conducted a systematic review and meta-analysis to examine how metabolic factors (particularly glucose) and sex hormone levels (progesterone and estradiol) influence cortisol reactivity to acute stress. We identified 21 studies (N = 1216 participants) and conducted random-effects meta-analyses for metabolic and hormonal states. Across studies, glucose administration was associated with a significant increase in cortisol responses to acute stress compared to fasting or nonglucose control conditions (d = 0.30, 95 % CI = [0.05, 0.60], BF10 = 2.42, NNT = 10.63). In contrast, the effects of sex hormones on cortisol responses were smaller and more variable, with both progesterone and estradiol showing weak and inconsistent associations. Our results highlight a robust modulatory role of metabolic state, specifically glucose availability, on HPA axis reactivity, while evidence for sex hormone effects remains inconclusive. Future research should focus on better harmonization of designs concerning sex hormones and systematically examine interactions between metabolic and hormonal states to better explain sex differences in the prevalences of metabolic and stress-related disorders.publishe
Functional near-infrared spectroscopy and vagus somatosensory evoked potentials add to the power of established parameters such as poor cognitive performance, dsyosmia and APOe genotype to predict cognitive decline over 8 years in the elderly
No full textAlzheimer’s dementia is the main cause of cognitive impairment in people over the age of 65, with Alzheimer’s disease starting presumably 10–15 years before the onset of clinical symptoms. It is therefore important to recognize dementia at an early stage and identify possible predictors. The existing methods, like different parameters of ß-Amyloid and Tau quantification in cerebrospinal fluid (CSF) or the living brain by measure of PET, are invasive and expensive. Therefore, the present study investigates the predictive value of a battery of clinical, neuropsychological, and blood parameters as well as two neurophysiological methods (functional near-infrared spectroscopy [fNIRS] and vagus somatosensory evoked potentials [VSEP]) which are easy to perform, less invasive and cost-efficient, for developing cognitive impairments in the elderly. In this longitudinal, prospective study, we enrolled 604 healthy participants between 70 and 77 years of age. The participants were invited back after a mean time interval of 3 years and 11 months, and after 7 years and 8 months, and their cognitive impairments were determined. Here we show that the development of cognitive impairments after approximately 8 years can be predicted not only by previously known risk factors such as ApoE4 risk alleles, dysosmia, or poor cognitive performance at baseline but that latency prolongation in the VSEP and altered functional activation patterns measured by NIRS at baseline also provide additional predictive value. We therefore suggest that both neurophysiological parameters, VSEP and NIRS, should be included in future studies, investigating the prediction of dementia.publishe