Colloidal hard-rod fluids near geometrically structured substrates

Density functional theory is used to study colloidal hard-rod fluids near an individual right-angled wedge or edge as well as near a hard wall which is periodically patterned with rectangular barriers. The Zwanzig model, in which the orientations of the rods are restricted to three orthogonal orientations but their positions can vary continuously, is analyzed by numerical minimization of the grand potential. Density and orientational order profiles, excess adsorptions, as well as surface and line tensions are determined. The calculations exhibit an enrichment [depletion] of rods lying parallel and close to the corner of the wedge [edge]. For the fluid near the geometrically patterned wall, complete wetting of the wall -- isotropic liquid interface by a nematic film occurs as a two-stage process in which first the nematic phase fills the space between the barriers until an almost planar isotropic -- nematic liquid interface has formed separating the higher-density nematic fluid in the space between the barriers from the lower-density isotropic bulk fluid. In the second stage a nematic film of diverging film thickness develops upon approaching bulk isotropic -- nematic coexistence.Comment: 9 pages, 9 figure

Where Comics and Cultural Heritage Meet: A Conversation with Damien Sueur and Yannis Koikas on BDnF: The Comics Factory

The Bibliothèque nationale de France (BnF; French National Library) recently launched a free comics creation desktop and mobile application, “BDnF”. Designed and produced by the BnF, BDnF is a digital creation tool for making comics and other multimedia stories, mixing illustration and text. BDnF allows users to engage creatively in specific aspects of comics (narrative construction, temporality, space, text/drawing/synergy, etc.). A key feature of the application is its integration of a wide variety of educational and iconographic resources, and in particular of the digital collections of the BnF. Initially launched in French, the English language option was launched in May 2020. This article introduces the application to an English-speaking audience through a conversation with Damien Sueur, Digital Production Manager at the Digital Publishing Department, and Yannis Koikas, Head of the Digital Publishing Department at the Bibliothèque nationale de France

Functional strengthening through synaptic scaling upon connectivity disruption in neuronal cultures

An elusive phenomenon in network neuroscience is the extent of neuronal activity remodeling upon damage. Here, we investigate the action of gradual synaptic blockade on the effective connectivity in cortical networks in vitro. We use two neuronal cultures configurations—one formed by about 130 neuronal aggregates and another one formed by about 600 individual neurons—and monitor their spontaneous activity upon progressive weakening of excitatory connectivity. We report that the effective connectivity in all cultures exhibits a first phase of transient strengthening followed by a second phase of steady deterioration. We quantify these phases by measuring GEFF, the global efficiency in processing network information. We term hyperefficiency the sudden strengthening of GEFF upon network deterioration, which increases by 20–50% depending on culture type. Relying on numerical simulations we reveal the role of synaptic scaling, an activity–dependent mechanism for synaptic plasticity, in counteracting the perturbative action, neatly reproducing the observed hyperefficiency. Our results demonstrate the importance of synaptic scaling as resilience mechanism. Author Summary Neuronal circuits exhibit homeostatic plasticity mechanisms to cope with perturbations or damage. A central mechanism is ‘synaptic scaling,’ a self-organized response in which the strength of neurons’ excitatory synapses is adjusted to compensate for activity variations. Here we present experiments in which the excitatory connectivity of in vitro cortical networks is progressively weakened through chemical action. The spontaneous activity and effective connectivity of the whole network is monitored as degradation progresses, and the capacity of the network for broad information communication is quantified through the global efficiency. We observed that the network responded to the perturbation by strengthening the effective connectivity, reaching a hyperefficient state for moderate perturbations. The study proves the importance of ‘synaptic scaling’ as a driver for functional reorganization and network-wide resilience

Testing the relevance of effective interaction potentials between highly charged colloids in suspension

Combining cell and Jellium model mean-field approaches, Monte Carlo together with integral equation techniques, and finally more demanding many-colloid mean-field computations, we investigate the thermodynamic behavior, pressure and compressibility of highly charged colloidal dispersions, and at a more microscopic level, the force distribution acting on the colloids. The Kirkwood-Buff identity provides a useful probe to challenge the self-consistency of an approximate effective screened Coulomb (Yukawa) potential between colloids. Two effective parameter models are put to the test: cell against renormalized Jellium models

Environmental management decision-making in certified hotels

This paper analyses environmental decision-making against two axes, motivations and decision-making processes, to understand the reasons for pro-environmental behaviour by the managements of Spanish Eco-management and Audit Scheme (EMAS)-certified hotels. Mixed methods were used to study perceptions of EMAS and reasons for being certified, with current and lapsed EMAS-certified firms triangulated against expert interviews and documentary evidence. Four groups of hotels were differentiated: Strategic hotels (22%) (with high levels of integrated environmental management), Followers (48%), Greenwashers (11%) and Laggers (19%) (with low levels of integrated environmental management). Most hotels were found to be internally driven in their purpose and ad hoc in their decision-making, with limited understanding of externally driven benefits and motivation for more systematic management systems. This questions the success of EMAS as both a continuous improvement management and as a market-based regulation tool for hotels. Few hotels overall related high environmental standards to the possibilities of gaining market advantage: most wished to avoid legal challenges. The paper also illustrates the ways in which hotels opportunistically switch certification systems to get what they see as a better deal. © 2011 Taylor & Francis

Colloids in light fields: particle dynamics in random and periodic energy landscapes

The dynamics of colloidal particles in potential energy landscapes have mainly been investigated theoretically. In contrast, here we discuss the experimental realization of potential energy landscapes with the help of light fields and the observation of the particle dynamics by video microscopy. The experimentally observed dynamics in periodic and random potentials are compared to simulation and theoretical results in terms of, e.g. the mean-squared displacement, the time-dependent diffusion coefficient or the non-Gaussian parameter. The dynamics are initially diffusive followed by intermediate subdiffusive behaviour which again becomes diffusive at long times. How pronounced and extended the different regimes are, depends on the specific conditions, in particular the shape of the potential as well as its roughness or amplitude but also the particle concentration. Here we focus on dilute systems, but the dynamics of interacting systems in external potentials, and thus the interplay between particle-particle and particle-potential interactions, is also mentioned briefly. Furthermore, the observed dynamics of dilute systems resemble the dynamics of concentrated systems close to their glass transition, with which it is compared. The effect of certain potential energy landscapes on the dynamics of individual particles appears similar to the effect of interparticle interactions in the absence of an external potential

Imagination in children entering culture

Although children are born in a world of already established cultural practices and social representations, the appropriation and internalisation of culture is not a task of reproduction but one of imaginative construction. The cultural development of the child offers an empirical opportunity to examine the role of the imagination in the practices whereby human children enter culture. In this chapter we focus on three such practices – care, play, and storytelling – to observe the imagination at work. We start by revisiting understandings of the imagination and propose a positive view that sees it as the human capacity to go beyond the immediate situation and play with possible realities. We suggest that the interplay between presence and absence, grounded in the interactions between self and other established by culture, is the defining feature of the imagination. Drawing on our research on children’s representations of the public sphere we explore the complexity of children’s imagination and propose a typology of engagement with the absent: the not yet there, impinged by anticipation and desire; the nowhere, pertaining to the fictional and the fantastic; and the elsewhere, characterised by absent elements the child is aware of through direct or indirect experience. Throughout the chapter, we are guided by the question of how these types of engagement with absence, which are central to the imagination, play out in practices of care, play, and storytelling. This exploration helps us understand the imagination as both an engine and a consequence of development, central for the cognitive, emotional and cultural development of the child and for the development of culture itself. By imagining the world both as what it is and as different from the way it is, we show that 1) children’s imaginative engagement guides the micro-genesis of cognition and macro-processes of cultural development and 2) it establishes the freedom to create as a key process in the realisation of self and society

The Humanities Matter!

The Humanities are academic disciplines that seek to understand and interpret the human experience, from individuals to entire cultures, engaging in the discovery, preservation, and communication of the past and present record to enable a deeper understanding of contemporary society. The Humanities encompass literature, classics, ancient and modern languages, history, philoso - phy, media studies, the fine and performing arts, and other related subjects. It can be a challenge to show the benefits the Humanities bring: in this infographic we gather available evidence to show the Humanities matter

Streamlining Deposit: An OJS to Repository Plugin (Pitch)

Pitch for Stremlining Deposit: An OJS Plugin, presented by Stephann Makri

Pressurometry and biomechanical study of the foot in padel

El pádel es un deporte muy practicado en países como España, Argentina y Brasil, pero existen poco artículos científicos que muestren la lesividad de su práctica. Los movimientos más frecuentes del pádel pueden incidir de forma lesiva en el pie y en la articulación del tobillo. Por ello el objetivo del presente estudio fue profundizar en el análisis del rol del pie en la ejecución de los movimientos más representativos del pádel mediante técnicas de video y de presurometría. El estudio fue dividido en dos partes: análisis presurométrico de dos gestos (carrera frontal y el split-step), y filmación del pié en el trascurso de dos partidos. Las principales conclusiones obtenidas del estudio son la importancia del antepié en los movimientos analizados, la importancia de un diseño específico del calzado para el pádel, y la importancia del entrenamiento neuromuscular y propioceptivo del complejo pie-tobillo, especialmente de los flexores plantares