Simulating Male Selfish Strategy in Reproduction Dispute

We introduce into the Penna Model for biological ageing one of the possible male mechanisms used to maximize the ability of their sperm to compete with sperm from other males. Such a selfish mechanism increases the male reproduction success but may decrease the survival probability of the whole female population, depending on how it acts. We also find a dynamic phase transition induced by the existence of an absorbing state where no selfish males survive.Comment: 7 pages, latex including 2 eps figure

A benign juvenile environment reduces the strength of antagonistic pleiotropy and genetic variation in the rate of senescence

The environment can play an important role in the evolution of senescence because the optimal allocation between somatic maintenance and reproduction depends on external factors influencing life expectancy. The aims of this study were to experimentally test whether environmental conditions during early life can shape senescence schedules, and if so, to examine whether variation among individuals or genotypes with respect to the degree of ageing differs across environments. We tested life-history plasticity and quantified genetic effects on the pattern of senescence across different environments within a reaction norm framework by using an experiment on the three-spined stickleback (Gasterosteus aculeatus, Linnaeus) in which F1 families originating from a wild annual population experienced different temperature regimes. Male sticklebacks that had experienced a more benign environment earlier in life subsequently reduced their investment in carotenoid-based sexual signals early in the breeding season, and consequently senesced at a slower rate later in the season, compared to those that had developed under harsher conditions. This plasticity of ageing was genetically determined. Both antagonistic pleiotropy and genetic variation in the rate of senescence were evident only in the individuals raised in the harsher environment. The experimental demonstration of genotype-by-environment interactions influencing the rate of reproductive senescence provides interesting insights into the role of the environment in the evolution of life histories. The results suggest that benign conditions weaken the scope for senescence to evolve and that the dependence on the environment may maintain genetic variation under selection

Psychophysiologische Untersuchungen zum Essverhalten

Introduction. Malnutrition is a global challenge with mortality rates caused by obesity surpassing those of undernutrition. Excessive and low quality food intake detrimentally impacts human and planetary health likewise. In contrast, high fiber diets are beneficial for host metabolism and for the environment. Yet, diet-related behaviour change remains challenging, both on the systemic and the individual level. It remains largely unclear how high fiber diets act on the host in detail, to what extent gut-brain communication is involved, and by which mechanisms eating behaviour may be modulated and maintained. To this end, I investigated underlying mechanisms of eating related psychophysiological markers in humans in three studies. Methods. I examined changes in brain connectivity networks as proxies for reward and selfreflective processing induced by severe weight loss through bariatric surgery in a clinical sample of obese compared to waiting list control patients (n = 48, Study 1). I combined data from two independent cross-sectional studies: overweight adults (n = 27) and post-bariatric surgery groups with age-, sex- and BMI-matched control groups (n = 40). Primary measures of interest were eating behaviour, microbial genera abundance, and fiber intake or weight loss success, respectively, next to short-chain fatty acids in feces and serum (Study 2). I analysed data from the LIFE-Adult cohort study (n = 8,943) relating habitual diet to weight status, depressive symptoms and personality traits (Study 3). Additionally, I conducted a withinsubject cross-over dietary intervention study (n = 60) including brain imaging, cognitive tasks and biomarkers, and a series of large-scale online studies (n = 16,379). Results. In Study 1, we found no significant post-surgery changes in brain connectivity in confirmatory analyses. Exploratory results showed increased connectivity between the reward network to medial posterior frontal regions relating to treatment success. In Study 2, eating behaviour linked differentially to two groups of microbial genera. Indeed, those linked to unhealthier eating were found to be informative of treatment success post-bariatric surgery, in terms of higher weight loss and improved eating traits. In Study 3, less frequent animal-based food intake was significantly related to lower BMI and to lower extraversion, not to depressive symptoms. Conclusion. These results propose a complex cross-talk between eating behaviour and psychophysiological markers and i) indicate a link between therapy-induced weight loss and reward-related brain processes, ii) provide first evidence for links between eating behaviour and gut microbiota and iii) replicate known associations of high fiber diets and weight status, as well as add new insights on diet-related differences in personality traits. Future interventional studies need to investigate causality of gut-brain communication and its mechanistic pathways related to fiber.Einleitung. Mangelernährung ist ein globales Problem, wobei die durch Adipositas verursachte Sterblichkeitsrate die der Unterernährung übersteigt. Eine übermäßige, minderwertige Ernährung wirkt sich gleichermaßen negativ auf die menschliche und planetare Gesundheit aus. Im Gegensatz dazu ist eine ballaststoffreiche Ernährung vorteilhaft für den Stoffwechsel und die Umwelt. Das Ernährungsverhalten zu verändern, bleibt jedoch eine Herausforderung, sowohl auf systemischer als auch auf individueller Ebene. Es ist weitestgehend unklar, wie eine ballaststoffreiche Ernährung auf den Wirt wirkt, inwieweit Darm-Hirn-Kommunikation beteiligt ist und durch welche Mechanismen das Essverhalten moduliert und beibehalten werden kann. Methoden. Ich untersuchte Veränderungen von Gehirnkonnektivität, die mit Belohnung und Selbst-Reflexion assoziiert sind, nach bariatrischer Operation in einer klinischen Stichprobe im Vergleich zu Wartelisten-Patient:innen (n = 48) (Studie 1). In zwei unabhängigen Querschnittsstudien mit übergewichtigen Erwachsenen (n = 27) und solchen nach bariatrischer Operation sowie Kontrollgruppen (n = 40), betrachtete ich Essverhalten, die Abundanz mikrobieller Gattungen und Ballaststoffzufuhr bzw. therapeutischen Erfolg, sowie kurzkettige Fettsäuren in Feces und Serum (Studie 2). Ich analysierte den Zusammenhang zwischen Ernährung mit Gewicht, Depressivität und Persönlichkeit (n = 8,943, Studie 3). Auch führte ich eine randomisierte Ernährungsintervention (n = 60) mit Bildgebung des Gehirns, kognitiven Aufgaben und Biomarkern, sowie eine Serie von Online-Studien (n = 16,379) durch. Ergebnisse. In Studie 1 wiesen konfirmative Analysen auf keine signifikanten Veränderungen der Gehirnkonnektivität nach bariatrischer Chirurgie hin. Explorative Ergebnisse zeigten eine erhöhte Konnektivität zwischen dem Belohnungsnetzwerk und einer medial-posterioren frontalen Region in Verbindung mit dem Therapieerfolg. In Studie 2 war Essverhalten unterschiedlich mit zwei Gruppen von Bakterien verbunden. Diejenigen, die mit ungesundem Essen in Verbindung standen, waren ebenso mit dem Therapieerfolg nach bariatrischer Operation assoziiert. In Studie 3 stand die seltenere Aufnahme von tierischen Lebensmitteln in signifikantem Zusammenhang mit einem niedrigeren BMI und geringerer Extraversion, nicht aber mit Depressivität. Schlussfolgerungen. Die Ergebnisse zeigen ein komplexes Zusammenspiel zwischen Essverhalten und psychophysiologischen Markern und i) weisen auf einen Zusammenhang zwischen therapiebedingter Gewichtsabnahme und belohnungsbezogenen Gehirnprozessen hin, ii) liefern erste Belege für Zusammenhänge zwischen Essverhalten und Darmmikrobiota und iii) replizieren Assoziationen zwischen ballaststoffreicher Ernährung und Gewicht, und bringen neue Erkenntnisse über ernährungsassoziierte Persönlichkeitsunterschiede. Interventionsstudien sollten die Kausalität der Darm-Hirn-Kommunikation und ihre mechanistischen Wege im Zusammenhang mit Ballaststoffen untersuchen

Highlight on the problems generated by p-coumaric acid analysis in fermentations

p-Coumaric acid is a natural hydroxycinnamic acid existing in grapes and wine. It is the precursor of the 4-ethylphenol molecule through the bioconversion reaction by Brettanomyces yeast. Chromatographic methods are the most common techniques to detect p-coumaric acid. It is known that this acid is highly unstable in analysis and fermentation experiments. This paper highlights the problems occurring in p-coumaric acid analysis in wine fermentation conditions when studying its bioconversion. First, it was shown that p-coumaric acid was unstable at elevated temperature. On the other hand, it was found that in our experimental conditions p-coumaric acid reacted with ethanol. This work revealed also that the p-coumaric acid is partially adsorbed on Brettanomyces yeast, certainly on cell walls. Because of these phenomena the quantity of p-coumaric acid which can participate to the bioconversion into ethylphenol decreases

Random Acts of STEM: A systematic review of local k-12 school division STEM experiences in Virginia

The initial purpose of the study was to determine whether the school divisions in Virginia have definitions of STEM education. For the divisions that have described STEM education, the following valuation was based on the precise STEM education definition each has implemented. The population for the study included all 132 school divisions in This mixed-methods study investigated the implementation of STEM programs in Virginia K-12 schools. Data were collected through two avenues: publicly available online resources from school divisions and interviews with STEM leaders in the Virginia educational system. Data analysis on these two sources yielded five themes: (a) existence of sense-making definition of STEM; (b) differentiated STEM programs; (c) scaling embedded STEM integration; (d) interest in STEM drives successful inclusion of gender, minority, and students with disabilities; and (e) standardized testing is a barrier to STEM participation

The sustainability argument for open science

Ever-increasing anthropogenic greenhouse gas emissions narrow the timeframe for humanity to mitigate the climate crisis. Scientific research activities are resource demanding and, consequently, contribute to climate change; at the same time, scientists have a central role in advancing knowledge, also on climate-related topics. In this opinion piece, we discuss (1) how open science – adopted on an individual as well as on a systemic level – can contribute to making research more environmentally friendly, and (2) how open science practices can make research activities more efficient and thereby foster scientific progress and solutions to the climate crisis. While many building blocks are already at hand, systemic changes are necessary in order to create academic environments that support open science practices and encourage scientists from all fields to become more carbon-conscious, ultimately contributing to a sustainable future

Dietary fiber and WHO food categories extension for the food-pics_extended database

Well characterized databases used for experimental purposes with extensive meta-data are essential for conducting meaningful and comparable studies. The Food-pics_extended database (Blechert et al., 2019) is one example for a widely used food stimulus database (original publication Blechert et al., 2014: 285 citations, and 2019: 32 citations). Indeed, meta-data on low level and high level image characteristics is broad, yet fiber ratings are not included, limiting its use in diet-related studies. Therefore, we developed fiber ratings per item (n = 562 stimuli), based on mean values of four non-expert raters. Ratings show good reliability (ICC = 0.77) and meaningful ranges per food type (mean fiber per 100 g by food type minbeverages = 0.04 ± 0.04 g and max Ready-to-eat savories = 4.49 ± 1.58). The newly provided fiber ratings enrich the already valuable database and extend it by an important nutrient value for human and planetary health

An Unusual Antagonistic Pleiotropy in the Penna Model for Biological Ageing

We combine the Penna Model for biological aging, which is based on the mutation-accumulation theory, with a sort of antagonistic pleiotropy. We show that depending on how the pleiotropy is introduced, it is possible to reproduce both the humans mortality, which increases exponentially with age, and fruitfly mortality, which decelerates at old ages, allowing the appearance of arbitrarily old Methuselah's.Comment: 8 pages, 3 figures, to appear in Physica