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After Fukushima : the precautionary principle revisited
(AOSIS Publishing, 2012-12-06) Huber, Wolfgang
Etienne de Villiers, more than other theologians, elaborates on basic elements of a Christian ethics of responsibility. He distinguishes between retrospective and prospective responsibility. The prospective aspect attracted awareness after the nuclear accident in the Fukushima reactors on 11 March 2011. The question on how to respond in an ethically responsible manner to catastrophic risks was put back on the agenda. The article takes up this question and discusses the answer given in the international debate by the introduction of the ‘precautionary principle’. The principle is described with its background in the ‘heuristics of fear’, proposed by the philosopher Hans Jonas. Four criticisms are discussed in detail relating to the problems of scientific uncertainty, the burden of proof, the weight of damages and the perils of precaution. That leads to a reformulation of the precautionary principle as a concrete element within an ethics of responsibility.
Age-dependent effects of UCP2 deficiency on experimental acute pancreatitis in mice
(PLoS, 2014-04-10) Muller, Sarah; Kaiser, Hannah; Kruger, Burkhard; Fitzner, Brit; Lange, Falko; Bock, Cristin N.; Nizze, Horst; Ibrahim, Saleh M.; Fuellen, Georg; Wolkenhauer, Olaf; Jaster, Robert
Reactive oxygen species (ROS) have been implicated in the pathogenesis of acute pancreatitis (AP) for many years but experimental evidence is still limited. Uncoupling protein 2 (UCP2)-deficient mice are an accepted model of age-related oxidative stress. Here, we have analysed how UCP2 deficiency affects the severity of experimental AP in young and older mice (3 and 12 months old, respectively) triggered by up to 7 injections of the secretagogue cerulein (50 μg/kg body weight) at hourly intervals. Disease severity was assessed at time points from 3 hours to 7 days based on pancreatic histopathology, serum levels of alpha-amylase, intrapancreatic trypsin activation and levels of myeloperoxidase (MPO) in lung and pancreatic tissue. Furthermore, in vitro studies with pancreatic acini were performed. At an age of 3 months, UCP2-/- mice and wild-type (WT) C57BL/6 mice were virtually indistinguishable with respect to disease severity. In contrast, 12 months old UCP2-/- mice developed a more severe pancreatic damage than WT mice at late time points after the induction of AP (24 h and 7 days, respectively), suggesting retarded regeneration. Furthermore, a higher peak level of alpha-amylase activity and gradually increased MPO levels in pancreatic and lung tissue were observed in UCP2-/- mice. Interestingly, intrapancreatic trypsin activities (in vivo studies) and intraacinar trypsin and elastase activation in response to cerulein treatment (in vitro studies) were not enhanced but even diminished in the knockout strain. Finally, UCP2-/- mice displayed a diminished ratio of reduced and oxidized glutathione in serum but no increased ROS levels in pancreatic acini. Together, our data indicate an aggravating effect of UCP2 deficiency on the severity of experimental AP in older but not in young mice. We suggest that increased severity of AP in 12 months old UCP2-/- is caused by an imbalanced inflammatory response but is unrelated to acinar cell functions.
Aid donors, democracy and the developmental state in Ethiopia
(Taylor & Francis, 2019-09-26) Brown, Stephen, 1967-; Fisher, Jonathan, 1985-
The “developmental state” has become a prominent alternative development model defended by contemporary Western aid donors, particularly in Africa. Purported “developmental states,” such as Ethiopia and Rwanda, are argued to possess strong-willed, visionary leaderships whose commitment to delivering on ambitious development plans renders them attractive donor partners. These leaderships are also, however, often authoritarian and unapologetic when criticized for democratic backsliding or human rights abuses. For many Western donors this represents a tolerable trade-off. The purpose of this article is to interrogate, critique and explain the assumptions and ideas underlying this trade-off. Using the case study of Ethiopia, we argue that donor officials’ understandings of “developmental state” are varied, vague and superficial, the main commonality being a “strong” regime with “political will” and a non-negotiable approach to domestic governance. We suggest that donors have too readily and uncritically accepted, internalized and deployed these notions, using the “developmental state” concept to justify their withdrawal from serious engagement on democratic reform. This derives from a systemic donor preference for depoliticized development models, as well as from Ethiopian officials’ own savvy political manoeuvrings. It has also, however, weakened donors’ position of influence at a time when the Ethiopian regime is debating major political reform.
Anaemia at antenatal care initiation and associated factors among pregnant women in West Gonja District, Ghana: a cross-sectional study
(Pan African Medical Journal, 2019-08-27) Tibambuya, Basil Addayire; Ganle, John Kuumuori; Ibrahim, Muslim
Introduction: anaemia in pregnancy remains a critical public health concern in many African settings; but its determinants are not clear. The purpose of this study was to assess anaemia at antenatal care initiation and associated factors among pregnant women in a local district of Ghana. Methods: a facility-based cross-sectional survey was conducted. A total of 378 pregnant women attending antenatal care at two health facilities were surveyed. Data on haemoglobin level, helminths and malaria infection status at first antenatal care registration were extracted from antenatal records booklets of each pregnant women. Questionnaires were then used to collect data on socio-demographic and dietary variables. Binary and multivariate logistic regression analyses were done to assess factors associated with anaemia. Results: the prevalence of anaemia was 56%, with mild anaemia being the highest form (31.0%). Anaemia prevalence was highest (73.2%) among respondents aged 15-19 years. Factors that significantly independently reduced the odds of anaemia in pregnancy after controlling for potential confounders were early (within first trimester) antenatal care initiation (AOR=5.01; 95% CI =1.41-17.76; p=0.013) and consumption of egg three or more times in a week (AOR=0.30; 95% CI=0.15-0.81; P=0.014). Conclusion: health facility and community-based preconception and conception care interventions must not only aim to educate women and community members about the importance of early ANC initiation, balanced diet, protein and iron-rich foods sources that may reduce anaemia, but must also engage community leaders and men to address food taboos and cultural prohibitions that negatively affect pregnant woman.
Annotation-based feature extraction from sets of SBML models
(BioMed Central, 2015-04-15) Alm, Rebekka; Waltemath, Dagmar; Wolfien, Markus; Wolkenhauer, Olaf; Henkel, Ron
Background: Model repositories such as BioModels Database provide computational models of biological systems for the scientific community. These models contain rich semantic annotations that link model entities to concepts in well-established bio-ontologies such as Gene Ontology. Consequently, thematically similar models are likely to share similar annotations. Based on this assumption, we argue that semantic annotations are a suitable tool to characterize sets of models. These characteristics improve model classification, allow to identify additional features for model retrieval tasks, and enable the comparison of sets of models. Results: In this paper we discuss four methods for annotation-based feature extraction from model sets. We tested all methods on sets of models in SBML format which were composed from BioModels Database. To characterize each of these sets, we analyzed and extracted concepts from three frequently used ontologies, namely Gene Ontology, ChEBI and SBO. We find that three out of the methods are suitable to determine characteristic features for arbitrary sets of models: The selected features vary depending on the underlying model set, and they are also specific to the chosen model set. We show that the identified features map on concepts that are higher up in the hierarchy of the ontologies than the concepts used for model annotations. Our analysis also reveals that the information content of concepts in ontologies and their usage for model annotation do not correlate. Conclusions: Annotation-based feature extraction enables the comparison of model sets, as opposed to existing methods for model-to-keyword comparison, or model-to-model comparison.
Anti-inflammatory effects of reactive oxygen species : a multi-valued logical model validated by formal concept analysis
(BioMed Central, 2014-09) Wollbold, Johannes; Jaster, Robert; Muller, Sarah; Rateitschak, Katja; Wolkenhauer, Olaf
Background: Recent findings suggest that in pancreatic acinar cells stimulated with bile acid, a pro-apoptotic effect of reactive oxygen species (ROS) dominates their effect on necrosis and spreading of inflammation. The first effect presumably occurs via cytochrome C release from the inner mitochondrial membrane. A pro-necrotic effect – similar to the one of Ca2+ – can be strong opening of mitochondrial pores leading to breakdown of the membrane potential, ATP depletion, sustained Ca2+ increase and premature activation of digestive enzymes. To explain published data and to understand ROS effects during the onset of acute pancreatitis, a model using multi-valued logic is constructed. Formal concept analysis (FCA) is used to validate the model against data as well as to analyze and visualize rules that capture the dynamics. Results: Simulations for two different levels of bile stimulation and for inhibition or addition of antioxidants reproduce the qualitative behaviour shown in the experiments. Based on reported differences of ROS production and of ROS induced pore opening, the model predicts a more uniform apoptosis/necrosis ratio for higher and lower bile stimulation in liver cells than in pancreatic acinar cells. FCA confirms that essential dynamical features of the data are captured by the model. For instance, high necrosis always occurs together with at least a medium level of apoptosis. At the same time, FCA helps to reveal subtle differences between data and simulations. The FCA visualization underlines the protective role of ROS against necrosis. Conclusions: The analysis of the model demonstrates how ROS and decreased antioxidant levels contribute to apoptosis. Studying the induction of necrosis via a sustained Ca2+ increase, we implemented the commonly accepted hypothesis of ATP depletion after strong bile stimulation. Using an alternative model, we demonstrate that this process is not necessary to generate the dynamics of the measured variables. Opening of plasma membrane channels could also lead to a prolonged increase of Ca2+ and to necrosis. Finally, the analysis of the model suggests a direct experimental testing for the model-based hypothesis of a self-enhancing cycle of cytochrome C release and ROS production by interruption of the mitochondrial electron transport chain.
The archaeology of teaching and the evolution of Homo docens
(University of Chicago Press, 2017-4) Gardenfors, Peter; Hogberg, Anders
Teaching is present in all human societies, while within other species it is very limited. Something happened during the evolution of Homo sapiens that also made us Homo docens—the teaching animal. Based on discussions of animal and hominin learning, we analyze the evolution of intentional teaching by a series of levels that require increasing capacities of mind reading and communication on the part of the teacher and the learner. The levels of teaching are (1) intentional evaluative feedback, (2) drawing attention, (3) demonstrating, (4) communicating concepts, and (5) explaining relations between concepts. We suggest that level after level has been added during the evolution of teaching.We demonstrate how different technologies depend on increasing sophistication in the levels of cognition and communication required for teaching them. As regards the archaeological evidence for the different levels, we argue that stable transmission of the Oldowan technology requires at least teaching by demonstration and that learning the late Acheulean hand-axe technology requires at least communicating concepts. We conclude that H. docens preceded H. sapiens.
Associations between the severity of obstructive lower urinary tract symptoms and care-seeking behavior in rural Africa : a cross-sectional survey from Uganda
(Public Library of Science, 2017) Stothers, Lynn; Macnab, Andrew J.; Bajunirwe, Francis; Mutabazi, Sharif; Berkowitz, Jonathan
Background: Global estimates indicate that by 2018 2.3 billion individuals worldwide will suffer from lower urinary tract symptoms (LUTS), with 1.1 billion having LUTS related to bladder outlet obstruction (BOO). Left untreated BOO in men causes irreversible changes to the urinary tract leading to urinary retention, the need for catheterization, renal failure and even death. Estimates suggest that Africa will be one of the continents with the greatest increase in (LUTS) by 2018 however direct measures in Africa are lacking. The objectives were to: (1) measure of prevalence of LUTS/BOO in a community-based sample of men in Africa, (2) compare community-based LUTS/BOO frequency to those seeking care for LUTS in a local clinic (3) quantify bother, interference with daily living, worry and quality of life related to LUTS/BOO between community and clinic settings and (4) examine relationships between socioeconomic and demographics related to LUTS/BOO. Methods and findings: 473 men from a rural Ugandan community (238 residents living with their symptoms and 177 presenting at a clinic for care) completed the International Prostate Symptom Scale (IPSS) and a 53-item validated LUTS symptom, bother and quality of life index. Severity of symptoms was categorized based on reference ranges for mild, moderate and severe levels of the IPSS, comparing those in the community versus those seeking care for symptoms. IPSS indicated that 55.9% of men in the community versus 17.5% of those at the clinic had mild symptoms, 31.5% in the community versus 52.5% of those at the clinic had moderate symptoms and 12.6% of those in the community versus 29.9% of those at the clinic had severe symptoms (p<0.001). Men seeking care for LUTS/BOO had a lower quality of life (p<0.05), were more bothered by their urinary symptoms (p<0.05), had more interference with daily activity and worry (p<0.05) but this did not have an impact on their general sense of wellbeing. Conclusions: The burden of disease of LUTS/BOO in this rural African cohort is high and significantly higher among those seeking care due to the bother of their symptoms. One in 4 men will spend money for transport to clinic due to LUTS/BOO despite low economic resources. Educational tools for patients structured to the level of literacy are justified.
Breaking down the silos of Universal Health Coverage : towards systems for the primary prevention of noncommunicable diseases in Africa
(BMJ Publishing Group, 2019) Oni, Tolu; Mogo, Ebele; Ahmed, Aliko; Davies, Justine I.
►African countries are not on track to achieve global targets for non-communicable disease (NCD) prevention, driven by an insufficient focus on ecological drivers of NCD risk factors, including poor urban development and the unbridled proliferation of the commercial determinants of health. ► As the risk factors for NCDs are largely shaped outside the healthcare sector, an emphasis on downstream healthcare service provision to the exclusion of upstream population-level prevention limits the goals of universal health coverage (UHC) and its potential for optimal improvements in (achieving) health and well-being outcomes in Africa. ► The political will for UHC in Africa will miss the opportunity to turn the tide of this emerging NCD epidemic in Africa, if not oriented to a systems for health rather than a solely healthcare-centric approach. A successful approach needs to proactively incorporate wider health determinants (sectors)—housing, planning, waste management, education, governance and finance, among others—in strategies to improve health. This includes aligning governance and accountability mechanisms and strategic objectives of all ‘health determinant’ sectors for health creation and long-term cost savings. ► Researchers have a vital role to play, collaborating with policy makers to provide evidence to support implementation and to facilitate knowledge sharing between African countries and globally.
Causal cognition, force dynamics and early hunting technologies
(Frontiers Media, 2018) Gardenfors, Peter; Lombard, Marlize
With this contribution we analyze ancient hunting technologies as one way to explore the development of causal cognition in the hominin lineage. Building on earlier work, we separate seven grades of causal thinking. By looking at variations in force dynamics as a central element in causal cognition, we analyze the thinking required for different hunting technologies such as stabbing spears, throwing spears, launching atlatl darts, shooting arrows with a bow, and the use of poisoned arrows. Our interpretation demonstrates that there is an interplay between the extension of human body through technology and expanding our cognitive abilities to reason about causes. It adds content and dimension to the trend of including embodied cognition in evolutionary studies and in the interpretation of the archeological record. Our method could explain variation in technology sets between archaic and modern human groups.
Cell-autonomous role of GFRα1 in the development of olfactory bulb GABAergic interneurons
(The Company of Biologists, 2018-05-18) Zechel, Sabrina; Fernandez-Suarez, Diana; Ibanez, Carlos F.
GFRα1, a receptor for glial cell line-derived neurotrophic factor (GDNF), is critical for the development of the main olfactory system. The olfactory bulb (OB) of Gfra1 knockout mice shows significant reductions in the number of olfactory sensory neurons, mitral and tufted cells, as well as all major classes of OB GABAergic interneurons. However, the latter do not express significant levels of GFRα1, leaving the mechanism of action of GFRα1 in OB interneuron development unexplained. Here we report that GFRα1 is highly expressed in the precursor cells that give rise to all major classes of OB interneurons, but is downregulated as these neurons mature. Conditional ablation of GFRα1 in embryonic GABAergic cells recapitulated the cell losses observed in global Gfra1 knockouts at birth. GFRα1 was also required for the sustained generation and allocation of OB interneurons in adulthood. Conditional loss of GFRα1 altered the migratory behaviour of neuroblasts along the rostral migratory stream (RMS) as well as RMS glial tunnel formation. Together, these data indicate that GFRα1 functions cellautonomously in subpopulations of OB interneuron precursors to regulate their generation and allocation in the mammalian OB.
Cerebral lateralization and religion : a phenomenological approach
(MDPI, 2019) McGilchrist, Iain
Both animal ethology and studies of the attentional styles of the two cerebral hemispheres in human subjects suggest that there is a degree of specialization, with the left hemisphere tending to focus more narrowly on detail, and the right hemisphere supporting sustained attention across a broad field. This has clear survival advantages. It also has consequences at the phenomenological level of integrated experience. Although both hemispheres are involved in all experience, the characteristics of right hemisphere phenomenology, in particular its greater capacity to sustain ambiguity, understand meaning that lies beyond language, and perceive systemic wholes, means that it is more likely to be able to accommodate religious thought and experience. Since critiques of religion tend to have the opposite characteristics (those of left hemisphere phenomenology), arguments about the nature and meaning of religion may depend on which hemisphere’s “version” of the world is privileged. Some consequent metaphysical, epistemological and ethical issues are explored, drawing on brain studies and a range of other disciplinary and experiential perspectives.
Childhood obesity in urban Ghana : evidence from a cross-sectional survey of in-school children aged 5–16 years
(BMC (part of Springer Nature), 2019-11-26) Ganle, John K.; Boakye, Priscilla P.; Baatiema, Leonard
Background: Childhood obesity is a growing public health concern in many low-income urban settings; but its determinants are not clear. The purpose of this study is to assess the prevalence of childhood obesity and associated factors among in-school children aged 5–16 years in a Metropolitan district of Ghana. Methods: A cross-sectional quantitative survey was conducted among a sample of 285 in-school children aged 5– 16 years. Pre-tested questionnaires and anthropometric data collection methods were used to collect data. Descriptive, bivariate, binary and multivariate logistic regression statistical techniques were used to analyse data. Results: Some 46.9% (42.2% for males and 51.7% for females) of the children were overweight. Of this, 21.2% were obese (BMI falls above 95th percentile). Childhood obesity was higher in private school (26.8%) than public school (21.4%), and among girls (27.2%) than boys (19%). Factors that increased obesity risks included being aged 11–16 as against 5–10 years (aOR = 6.07; 95%CI = 1.17–31.45; p = 0.025), having a father whose highest education is ‘secondary’ (aOR =2.97; 95% CI = 1.09–8.08; p = 0.032), or ‘tertiary’ (aOR = 3.46; 95% CI = 1.27–9.42; p = 0.015), and consumption of fizzy drinks most days of the week (aOR = 2.84; 95% CI = 1.24–6.52; p = 0.014). Factors that lowered obesity risks included engaging in sport at least 3times per week (aOR = 0.56; 95% CI = 0.33–0.96; p = 0.034), and sleeping for more than 8 h per day (aOR = 0.38; 95% CI = 0.19–0.79; p = 0.009). Conclusion: Higher parental (father) educational attainment and frequent consumption of fizzy drinks per week may increase obesity risks among in-school children aged 5–16 years in the Metropolitan district of Ghana. However, regular exercise (playing sport at least 3 times per week) and having 8 or more hours of sleep per day could lower obesity risks in the same population. Age and sex-appropriate community and school-based interventions are needed to promote healthy diet selection and consumption, physical activity and healthy life styles among in-school children.
COMODI : an ontology to characterise differences in versions of computational models in biology
(BioMed Central, 2016-07-11) Scharm, Martin; Waltemath, Dagmar; Mendes, Pedro; Wolkenhauer, Olaf
Background: Open model repositories provide ready-to-reuse computational models of biological systems. Models within those repositories evolve over time, leading to different model versions. Taken together, the underlying changes reflect a model’s provenance and thus can give valuable insights into the studied biology. Currently, however, changes cannot be semantically interpreted. To improve this situation, we developed an ontology of terms describing changes in models. The ontology can be used by scientists and within software to characterise model updates at the level of single changes. When studying or reusing a model, these annotations help with determining the relevance of a change in a given context. Methods: We manually studied changes in selected models from BioModels and the Physiome Model Repository. Using the BiVeS tool for difference detection, we then performed an automatic analysis of changes in all models published in these repositories. The resulting set of concepts led us to define candidate terms for the ontology. In a final step, we aggregated and classified these terms and built the first version of the ontology. Results: We present COMODI, an ontology needed because COmputational MOdels DIffer. It empowers users and software to describe changes in a model on the semantic level. COMODI also enables software to implement user-specific filter options for the display of model changes. Finally, COMODI is a step towards predicting how a change in a model influences the simulation results. Conclusion: COMODI, coupled with our algorithm for difference detection, ensures the transparency of a model’s evolution, and it enhances the traceability of updates and error corrections. COMODI is encoded in OWL. It is openly available at http://comodi.sems.uni-rostock.de/.
Competition between silicifiers and non-silicifiers in the past and present ocean and its evolutionary impacts
(Frontiers Media, 2018) Hendry, Katharine R.; Marron, Alan O.; Vincent, Flora; Conley, Daniel J.; Gehlen, Marion; Ibarbalz, Federico M.; Queguiner, Bernard; Bowler, Chris
Competition is a central part of the evolutionary process, and silicification is no exception: between biomineralized and non-biomineralized organisms, between siliceous and non-siliceous biomineralizing organisms, and between different silicifying groups. Here we discuss evolutionary competition at various scales, and how this has affected biogeochemical cycles of silicon, carbon, and other nutrients. Across geological time we examine how fossils, sediments, and isotopic geochemistry can provide evidence for the emergence and expansion of silica biomineralization in the ocean, and competition between silicifying organisms for silicic acid. Metagenomic data from marine environments can be used to illustrate evolutionary competition between groups of silicifying and non-silicifying marine organisms. Modern ecosystems also provide examples of arms races between silicifiers as predators and prey, and how silicification can be used to provide a competitive advantage for obtaining resources. Through studying the molecular biology of silicifying and non-silicifying species we can relate how they have responded to the competitive interactions that are observed, and how solutions have evolved through convergent evolutionary dynamics.
Consumer-resource dynamics : quantity, quality, and allocation
(Public Library of Science, 2011-01-20) Getz, Wayne M.; Owen-Smith, Norman
Background: The dominant paradigm for modeling the complexities of interacting populations and food webs is a system of coupled ordinary differential equations in which the state of each species, population, or functional trophic group is represented by an aggregated numbers-density or biomass-density variable. Here, using the metaphysiological approach to model consumer-resource interactions, we formulate a two-state paradigm that represents each population or group in a food web in terms of both its quantity and quality. Methodology and Principal Findings: The formulation includes an allocation function controlling the relative proportion of extracted resources to increasing quantity versus elevating quality. Since lower quality individuals senesce more rapidly than higher quality individuals, an optimal allocation proportion exists and we derive an expression for how this proportion depends on population parameters that determine the senescence rate, the per-capita mortality rate, and the effects of these rates on the dynamics of the quality variable. We demonstrate that oscillations do not arise in our model from quantity-quality interactions alone, but require consumer-resource interactions across trophic levels that can be stabilized through judicious resource allocation strategies. Analysis and simulations provide compelling arguments for the necessity of populations to evolve quality-related dynamics in the form of maternal effects, storage or other appropriate structures. They also indicate that resource allocation switching between investments in abundance versus quality provide a powerful mechanism for promoting the stability of consumer-resource interactions in seasonally forcing environments. Conclusions/Significance: Our simulations show that physiological inefficiencies associated with this switching can be favored by selection due to the diminished exposure of inefficient consumers to strong oscillations associated with the wellknown paradox of enrichment. Also our results demonstrate how allocation switching can explain observed growth patterns in experimental microbial cultures and discuss how our formulation can address questions that cannot be answered using the quantity-only paradigms that currently predominate. © 2011 Getz, Owen-Smith.
A continuous-time persistent random walk model for flocking
(AIP Publishing, 2018) Escaff, Daniel; Toral, Raul; Van den Broeck, Christian; Lindenberg, Katja
A classical random walker is characterized by a random position and velocity. This sort of random walk was originally proposed by Einstein to model Brownian motion and to demonstrate the existence of atoms and molecules. Such a walker represents an inanimate particle driven by environmental fluctuations. On the other hand, there are many examples of so-called “persistent random walkers,” including self-propelled particles that are able to move with almost constant speed while randomly changing their direction of motion. Examples include living entities (ranging from flagellated unicellular organisms to complex animals such as birds and fish), as well as synthetic materials. Here we discuss such persistent non-interacting random walkers as a model for active particles. We also present a model that includes interactions among particles, leading to a transition to flocking, that is, to a net flux where the majority of the particles move in the same direction. Moreover, the model exhibits secondary transitions that lead to clustering and more complex spatially structured states of flocking. We analyze all these transitions in terms of bifurcations using a number of mean field strategies (all to all interaction and advection-reaction equations for the spatially structured states), and compare these results with direct numerical simulations of ensembles of these interacting active particles. Interacting self-propelled particles have the potential to exhibit a number of self-coordinated motions. Nature offers many examples surprising for their beauty, such as flocking birds or swarming fish. The keys to understanding the emergence of such collective behaviors are two: the motion of the self-propelled entities themselves and the interaction that leads to the coordination. In this work, we present a mathematical model for the sort of self-propelled particles that under appropriate conditions are capable of collective motions. This model deepens our understanding of the emergence of collective motion in terms of the theoretical framework provided by nonequilibrium statistical mechanics and nonlinear physics.
Coupling, reinforcement, and speciation
(University of Chicago Press, 2018) Butlin, Roger K.; Smadja, Carole M.
During the process of speciation, populations may diverge for traits and at their underlying loci that contribute barriers to gene flow. These barrier traits and barrier loci underlie individual barrier effects, by which we mean the contribution that a barrier locus or trait—or some combination of barrier loci or traits—makes to overall isolation. The evolution of strong reproductive isolation typically requires the origin of multiple barrier effects. Critically, it also requires the coincidence of barrier effects; for example, two barrier effects, one due to assortative mating and the other due to hybrid inviability, create a stronger overall barrier to gene flow if they coincide than if they distinguish independent pairs of populations. Here, we define “coupling” as any process that generates coincidence of barrier effects, resulting in a stronger overall barrier to gene flow. We argue that speciation research, both empirical and theoretical, needs to consider both the origin of barrier effects and the ways in which they are coupled. Coincidence of barrier effects can occur either as a by-product of selection on individual barrier effects or of population processes, or as an adaptive response to indirect selection. Adaptive coupling may be accompanied by further evolution that enhances individual barrier effects. Reinforcement, classically viewed as the evolution of prezygotic barriers to gene flow in response to costs of hybridization, is an example of this type of process. However, we argue for an extended view of reinforcement that includes coupling processes involving enhancement of any type of additional barrier effect as a result of an existing barrier. This view of coupling and reinforcement may help to guide development of both theoretical and empirical research on the process of speciation.
COVID-19 Disease map, building a computational repository of SARS-CoV-2 virus-host interaction mechanisms
(Springer Nature, 2020) Ostaszewski, Marek; Mazein, Alexander; Gillespie, Marc E.; Kuperstein, Inna; Niarakis, Anna; Hermjakob, Henning; Pico, Alexander R.; Willighagen, Egon L.; Evelo, Chris T.; Hasenauer, Jan; Schreiber, Falk; Drager, Andreas; Demir, Emek; Wolkenhauer, Olaf; Furlong, Laura I.; Barillot, Emmanuel; Dopazo, Joaquin; Orta-Resendiz, Aurelio; Messina, Francesco; Valencia, Alfonso; Funahashi, Akira; Kitano, Hiroaki; Auffray, Charles; Balling, Rudi; Schneider, Reinhard
We announce the COVID-19 Disease Map (https://doi.org/10.17881/covid19-disease-map), an effort to build a comprehensive, standardized knowledge repository of SARS-CoV-2 virus-host interaction mechanisms, guided by input from domain experts and based on published work. This knowledge, available in the vast body of existing literature1,2 and the fast-growing number of new SARS-CoV-2 publications, needs rigorous and efficient organization in both human and machine-readable formats.
The cultural semiotics of African encounters : eighteenth-century images of the Other
(De Gruyter, 2020-01-11) Duner, David
This a contribution to the cultural semiotics of African cultural encounters seen through the eyes of Swedish naturalists at the end of the eighteenth century. European travellers faced severe problems in understanding the alien African cultures they encountered; they even had difficulty understanding the other culture as a culture. They were not just other cultures that they could relate to, but often something completely different, belonging to the natural history of the human species. The Khoikhoi and other groups were believed by Europeans to be, from their perspective, the most distant culture. The Linnaean disciple Anders Sparrman and others, however, tried to transcend this cultural gap, and used their cognitive resources, such as empathy and intersubjectivity, in order to understand the alien culture they encountered. The aim of this paper is to unearth the cultural semiosis of African encounters and the intersubjective challenges that human interactions provoke. These encounters not only changed the view the travellers had of the Other, but also changed themselves and their self-perception. The encounter between the Ego and the Other is, however, not static, something predestined by the differences in their cultures, but dynamic, changing according to individual encounters and the actual intersubjective interplay that transform and change the perception of the Other. There are in particular four meaning-making processes and challenges within cultural encounters that are in focus: recognizing cultural complexity; invoking intersubjectivity; determining similarities and dissimilarities; and identifying the Other as a mirror of oneself. The triad of cultures – Ego, Alter, and Alius – can be understood as gradual and changing aspects depending on the actual situation of the encounter and the personal perspectives, interpretations, and behaviour of the thinking subjects involved. Using concrete examples from Southern and Western Africa in the 1770s and 1780s, this study aims to explore this dynamic semiosis. One of the conclusions is that the relation between the Ego and the Alter/Alius is not something only predetermined by the cultures involved and their ideologies, but also depends on the individual thinking subjects and how they use their specific cognitive and semiotic resources, not least their intersubjective abilities, within specific temporal and spatial contexts.

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