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The influence of glucose administration on stress reactivity and long-term memory in adult men and women
No full textStress and the associated cortisol release have profound effects on long-term memory (LTM). While glucose increases the cortisol stress response and exhibits memory enhancing effects in non-stressful situations, the interaction of glucose and stress on LTM has rarely been studied. The aim of this study was to investigate whether the glucose-related amplification of the cortisol stress response would enhance LTM formation. Overall, N = 62 healthy, fasted adults (age M = 23.13, SD = 3.02; 54.84 % female) participated. They consumed a drink containing water or glucose and underwent a non-stressful control task or the Trier Social Stress Test with Objects, during which panel members interact with certain objects (central) while leaving others untouched (peripheral). At the estimated cortisol peak, they encoded a wordlist. On the next day, they retrieved the objects and the words. We repeatedly assessed subjective stress, salivary cortisol and blood glucose concentrations and recorded an electrocardiogram. Glucose increased blood glucose concentrations, and the stressor led to a significant increase in cortisol as compared with the control task. Changes in cortisol were more pronounced in the glucose as compared with the water groups. Heart rate was elevated in the glucose as compared with the water groups during the recovery. Central objects were better remembered than peripheral objects when encoded during stress. Additionally, emotional words were remembered better as compared with neutral words. These effects were not modulated by glucose. These findings suggest that emotional information is remembered better than neutral information independent of stress and glucose intake. Stress enhances LTM of stressor-relevant information and glucose intake increases the cortisol stress response. However, these factors do not appear to interact. Glucose availability may thus play a less decisive role when memorizing a stressful episode.publishe
Steak is Not the Only Meat : Men Opt for Unconventional Meat Products When Mitigating Masculinity Threat
No full textGrounding our research in the symbolic self completion theory, we explored situations in which men are particularly motivated to consume meat and unconventional meat products, even when considered disgusting. We tested whether men compensate their experience of masculinity threat by opting for meat, including red meat, white larvae and offal. We also examined whether disgust towards products and their perception as feminine affect such decisions. In Study 1 (N = 247), men opted for more meat products when feeling self-incomplete in their masculinity. In Study 2 (N = 256), spicy edible larvae were preferred by men made to feel incomplete in their masculinity compared to those who felt complete, but the effect was significant only when considering the extent to which insects were perceived as disgusting and repulsive. Study 3 (N = 156) showed that preparing disgusting offal during a cooking course may compensate for feeling self-incomplete but only when it is not perceived as feminine. We discuss new research avenues and point to other boundary conditions that affect using various meat products in order to compensate for feelings of self-incompleteness in masculinity.publishe
Experimental investigation of stochastic resetting in a non-Markovian environment
No full textStochastic resetting (SR), in which a system intermittently returns to a fixed location, is a powerful strategy for optimizing search processes. While extensively studied in memoryless (Markovian) systems, its behavior in complex media with memory remains largely unexplored. Here, we experimentally investigate SR in a viscoelastic fluid by tracking a colloidal particle subjected to intermittent resets. In this non-Markovian environment, the fluid’s memory gives rise to elastic restoring forces that oppose the reset, pulling the particle back toward its prior position and hindering efficient exploration. We show that these memory effects can be actively controlled: by holding the particle at the trap center for a sufficient time, the fluid relaxes, erasing its memory and allowing the system to re-equilibrate. When introducing a fixed target site, we find that this memory control enables a significant reduction in the mean passage time, with optimal search performance emerging at intermediate resetting frequencies. In this regime, memory enhances performance through a ‘bunching’ effect, in which the particle rapidly revisits the target due to temporal correlations in its trajectory. These results highlight the dual role of memory in resetting dynamics-as both a hindrance and a resource-and suggest new strategies for optimizing search in non-Markovian systems, with potential applications in soft matter, biological transport, and stochastic control.publishe
Habitat Selection and Seed Dispersal by the Great Blue Turaco ( <i>Corythaeola cristata</i> ) in the Rainforests of Southern Cameroon
No full textTropical rainforests are biodiversity hotspots, where the seeds of 60%–90% of trees are dispersed by animals, yet movement data needed to understand the behaviors and habitat selection of tropical frugivores remain scarce. We GPS-tracked four great blue turacos (Corythaeola cristata) in the Dja Faunal Reserve of southern Cameroon and predicted spatial patterns of seed dispersal within each bird's home range, which covered up to 2.33 km2. Using integrated Step Selection Analyses, we related turaco movements to LiDAR-derived measurements of 3D vegetation structure and habitat type. One individual preferred areas of tall canopy height, whereas one preferred intermediate canopy height and avoided swamps and areas of greater vertical vegetation complexity. Seed dispersal patterns for the two turacos with the largest home ranges were predicted to be more diffuse, with local maxima almost an order of magnitude smaller than those with smaller home ranges. Although the great blue turaco is a common bird species throughout central African forests, this is the first study to characterize the species' movement ecology using telemetry. The observed individual variation in movement and habitat use underscores the need to track a broader range of species in central African landscapes, which are increasingly threatened by hunting, logging, habitat loss, and climate change.publishe
Social progress at the expense of economic equality? : New data on left parties' equality preferences
No full textHave concerns about equal rights and equal chances crowded out economic equality as a priority of left parties? Despite the increased importance of inequality in political science, this contentiously fought debate has been standing on shaky empirical foundations. While voter's equality preferences are well understood, parties’ equality emphases remain uncharted territory. This research note assesses whether the Left has replaced its emphasis on economic equality with a focus on equal chances and equal rights. Based on a new dataset of 300,000 party statements, we use online crowd-coding to map the equality trajectories of left parties in 12 OECD countries from 1970 to 2020. We examine if trade-offs between economic and non-economic aspects of inequality have come to dominate left parties’ equality profiles. Distinguishing social democratic, green and far-left parties, we refute a meritocratic or ‘woke’ crowding out of redistribution. Yet, Social Democrats have indeed forsaken the once complementary link between economic equality and equal rights in favour of a weak trade-off.publishe
Habitat Differences in Resource Density and Distribution Affect Ecology and Life History of a Landscape-Modifying Fish
No full textResource heterogeneity is a widespread phenomenon, as resources are rarely spaced evenly across a landscape. Variation in resource density and distribution can have a myriad of behavioural, ecological, and evolutionary consequences for populations, yet clarifying these effects is still challenging. We combine both novel and previously published data on genetic parentage, relatedness, life history, and predation to present a comprehensive field study of a shell bed in Lake Tanganyika. Here, a wild population of the cichlid fish Neolamprologus multifasciatus is naturally subdivided into habitat regions that differ immensely in shelter density and distribution, as well as in the capacity for the fish to physically rearrange their shelters into clusters (i.e., engage in niche construction). Shelters were evenly, densely, and continuously spaced in one habitat, while they were highly clustered in the other habitat. We expected the environmental potential for polygyny to be greater in the clustered habitat relative to the continuous habitat. Predation regimes and life history traits differed, with N. multifasciatus in the evenly distributed habitat experiencing higher predation threats, earlier maturation, and slower growth than those in the clustered habitat. Metrics of selection, however, were surprisingly consistent between the two habitats, as were patterns of dispersal. Overall, our research leverages the natural subdivision of a wild population into distinct habitats to investigate the ecological and evolutionary implications of resource heterogeneity and habitat modification.publishe
Exploring the fascination of metal-sulfur bonds, vivid colors, and electron transfer through proteins : A tribute to Harry B. Gray
No full textThe study of transition metals and their role in living matter has a long and distinguished history. This field, today referred to as Bioinorganic Chemistry, has evolved into a vibrant area of research. Progress is fueled by four main factors: (1) the use of high-tech spectroscopy to explore the structural and dynamic properties of molecules, (2) the molecular engineering and design of artificial enzymes, (3) the rapid determination of high-resolution structures of proteins and large protein complexes, and (4) the significant advancements in computational chemistry. First, I will take the reader on a brief journey “Meeting Harry B. Gray”. Hereafter, significant basic work in the laboratory and crucial key findings will be presented that have enhanced our understanding of the structural and functional features of notable metalloenzymes with unique catalytic sites: (i) the blue type-1 Cu center and the trinuclear O2 activating Cu cluster in ascorbate oxidase, (ii) the purple mixed-valent [Cu1.5+(CyS−)2Cu1.5+] copperA electron transfer center in nitrous oxide reductase and cytochrome c oxidase, (iii) intraprotein control of electron transfer rates by allosteric interactions within the green nitrite reductase cytochrome cd1, and (iv) active site structure and reaction mechanism of the red pentaheme cytochrome c nitrite reductase based on crystallographic identification of reaction intermediates and density functional calculations. This topic is particularly apt for honoring Harry B. Gray, who has made numerous seminal contributions to modern Inorganic Chemistry, especially as we celebrate his 90th birthday.publishe
Salivary cytokines in stress research : Reactivity kinetics in response to placebo-controlled acute psychosocial stress and associations with plasma cytokines and endocrine stress markers
No full textpublishe
No differences between males and females in the neural control of explosive contractions
No full textMales and females exhibit comparable explosive relative to maximal strength. Given the greater proportion of type I fibres area in female muscles, motor units discharge rate (MUDR) in explosive efforts may be higher to compensate for slower contractile properties. To verify this, 22 females and 12 males (20-34 y), performed 10 rapid isometric ankle dorsiflexors, while recording high-density electromyography from tibialis anterior. Relative rate of torque development (RTD) measures (normalised to maximal torque) in the first 150 ms from contraction onset were not different (P > 0.07) between sexes, nor MUDR at the beginning of the explosive efforts (61 ± 15 vs. 67 ± 16 Hz; P = 0.23). Time to peak RTD was shorter in males (61 ± 12 vs. 74 ± 14 ms; P < 0.01). Thus, despite faster torque kinetics in males, the control of rapid torque production does not differ between sexes.publishe