Computational approaches to substrate-based cell motility

Substrate-based crawling motility of eukaryotic cells is essential for many biological functions,both in developing and mature organisms.Motility dysfunctions are involved in several life-threatening pathologies such as cancer and metastasis.Motile cells are also a natural realisation of active,self-propelled‘particles’,a popular research topic in nonequilibrium physics.Finally,from the materials perspective,assemblies of motile cells and evolving tissues constitute a class of adaptive self-healing materials that respond to the topography,elasticity and surface chemistry of the environment and react to external stimuli.Although a comprehensive understanding of substrate-based cell motility remains elusive,progress has been achieved recently in its modelling on the whole-cell level.Here we survey the most recent advances in computational approaches to cell movement and demonstrate how these models improve our understanding of complex self-organised systems such as living cells.

A Genealogical Study of Facemasks in China:From Hygienic Modernity to Care

Despite the omnipresence of facemasks in the ongoing COVID-19 pandemic,recent studies on their sociopolitical aspects remain insufficient.This article conducts a genealogical study that investigates the emergence of two differing masking strategies in two epidemic events in Chinese history.First,during the Manchurian plague 1910/11,it shows how the germ theory and historical anecdotes made anti-plague masks thinkable and practicable as a solution not only for airborne contagion but also for the biopolitical problem of‘unhygienic’population.In the second part,the analytical focus is shifted to the emergence of collective mask-wearing practices during SARS 2002/03 from the vantage point of subjectification.Facemasks then became a symbol of care in the neoliberal regime of responsibilization.This article concludes by arguing for a rethinking of facemasks as actants who actively participate in the constitution of the world we share.

The Sasaki–Ricci Flow on Sasakian 3-Spheres

We show that on a Sasakian 3-sphere the Sasaki-Ricci flow initiating from a Sasakian metric of positive transverse scalar curvature converges to a gradient Sasaki-Ricci soliton.We also show the existence and uniqueness of gradient Sasaki-Ricci soliton on each Sasakian 3-sphere.

Grazing effects on vegetation dynamics in the savannah ecosystems of the Sahel

Background The savannah ecosystems of Sahel have experienced continuous and heavy grazing of livestock for centuries but still,their vegetation response to grazing pressure remains poorly understood.In this study,we analysed the herbaceous plant dynamics,measured by species diversity,composition,cover,and biomass in response to grazing pressure in the savannah ecosystems of Sahel.In Senegal,we selected four savannah sites represented with high,moderate,light and no grazing intensity levels.Transect survey methods were used for sampling the vegetation data within each of the sites.Species richness and composition were analysed using species accumulation curve and multivariate analyses.Furthermore,we used General Linear Models and a piecewise Structural Equation Model(pSEM)to examine the relationships between grazing intensity,vegetation cover,diversity and biomass.Results The herbaceous species diversity and composition varied significantly among the different grazing intensity levels(p<0.001).The plant species composition shifted from the dominance of grass cover to the dominance of forb cover with increasing grazing pressure.Moreover,the attributes of species diversity,herbaceous biomass,and ground cover were higher on sites with low grazing than sites with high and moderate grazing intensity.Across all sites,species diversity was positively related to total biomass.The pSEM explained 37%of the variance in total biomass and revealed that grazing intensity negatively influenced total biomass both directly and indirectly through its negative influence on species diversity.Conclusions Managing grazing intensity may lead to higher plant production and higher mixed forage establishment in the dryland savannah ecosystems.This information can be used to support land management strategies and promote sustainable grazing practices that balance the needs of livestock with the conservation of ecosystem health and biodiversity.

Prospective Merger Between Car-Parrinello and Lattice Boltzmann Methods for Quantum Many-Body Simulations

Formal analogies between the Car-Parrinello(CP)ab-initio molecular dynamics for quantum many-body systems,and the Lattice Boltzmann(LB)method for classical and quantum fluids,are pointed out.A theoretical scenario,whereby the quantum LB would be coupled to the CP framework to speed-up many-body quantum simulations,is also discussed,together with accompanying considerations on the computational efficiency of the prospective CP-LB scheme.