Diaspora: (post)colonial visions

The exhibition 'Diaspora: (Post)colonial Visions’ is part of the project ‘Memory Matters’, a partnership between the School of Social Policy, Sociology and Social Research (University of Kent) and CORECOG, a Congolese community group based in East London. The exhibition documents the ways in which project participants, mostly British Congolese young people, engaged discursively and visually with the urban and socio-historical spaces of (post)colonial memories. Through a series of heritage workshops organised in London and a 3-day visit to Brussels, several aspects of (post)colonial material representations and legacies were explored. In Brussels, the young people participated in an urban tour of the city’s colonial monuments and a visit to the Royal Museum for Central Africa (RMCA) a ‘Little Versailles’, dreamt by the Belgian king Leopold II to stage the grandeur of its colonial rule. Between 1885 and 1908 Leopold II was the sole owner of the ‘Congo Free State’, almost 80 times the size of Belgium. He implemented a harsh forced labour regime in the Congo to extract principally rubber as well as other natural riches. Coined the ‘only colonial museum left in the world’, and still bearing the ubiquitous mark of Leopold II, the RCMA is now undergoing major refurbishment and renovation. The museum exhibits unique ethnographic collections but also showcases a whole universe of colonial fantasies. Civilising desires and animalised aesthetics of a ‘primitive Other’ are conveyed through decontextualized and a-temporal visions of an imagined ‘Africa’ - a ‘Heart of Darkness’ turned ‘art of darkness’. ‘Diaspora: (Post)colonial Visions’ is also a witness to the struggle of Congolese activists in London, engaged in long-distance transnational politics and opposing the current Congolese government. Organising flashmobs, protests and demonstrations some of these activists denounce the exploitation of peoples and the plunder of mineral resources by a host of national and international actors, including multinational companies. Their public presence in the centre of London, at the heart of the ‘global city’ and former imperial capital, suggests the extent to which appropriating urban spaces and reclaiming visibility also serves to reconnect colonial past(s) and postcolonial present(s)

High-frequency capillary waves excited by oscillating microbubbles

This fluid dynamics video shows high-frequency capillary waves excited by the volumetric oscillations of microbubbles near a free surface. The frequency of the capillary waves is controlled by the oscillation frequency of the microbubbles, which are driven by an ultrasound field. Radial capillary waves produced by single bubbles and interference patterns generated by the superposition of capillary waves from multiple bubbles are shown.Comment: This video is an entry for the 2013 Gallery of Fluid Motion. A high-resolution and a low-resolution video are included as ancillary file

Incoherencias y pensamiento matemático: la influencia de los lenguajes matemáticos y representaciones sobre el razonamiento en el dominio del infinito

Las ideas, resultados y reflexiones que desarrollamos, son producto de estudios y parte de investigaciones (Garbin 2000 y Garbin, 2003,2004) que han pretendido contribuir con el debate de la problemática del infinito matemático en su dualidad potencial-actual, desde la específica, que genera la influencia de las representaciones y distintos lenguajes matemáticos sobre las percepciones del infinito y razonamientos matemáticos asociados, y en las inconsistencias e incoherencias de las respuestas de los alumnos a problemas que están presentes procesos infinitos

Hydrological controls on river network connectivity

This study proposes a probabilistic approach for the quantitative assessment of reach- and network-scale hydrological connectivity as dictated by river flow space–time variability. Spatial dynamics of daily streamflows are estimated based on climatic and morphological features of the contributing catchment, integrating a physically based approach that accounts for the stochasticity of rainfall with a water balance framework and a geomorphic recession flow analysis. Ecologically meaningful minimum stage thresholds are used to evaluate the connectivity of individual stream reaches, and other relevant network-scale connectivity metrics. The framework allows a quantitative description of the main hydrological causes and the ecological consequences of water depth dynamics experienced by river networks. The analysis shows that the spatial variability of local-scale hydrological connectivity is strongly affected by the spatial and temporal distribution of climatic variables. Depending on the underlying climatic settings and the critical stage threshold, loss of connectivity can be observed in the headwaters or along the main channel, thereby originating a fragmented river network. The proposed approach provides important clues for understanding the effect of climate on the ecological function of river corridors

Forced desorption of nanoparticles from an oil-water interface.

While nanoparticle adsorption to fluid interfaces has been studied from a fundamental standpoint and exploited in application, the reverse process, that is, desorption and disassembly, remains relatively unexplored. Here we demonstrate the forced desorption of gold nanoparticles capped with amphiphilic ligands from an oil-water interface. A monolayer of nanoparticles is allowed to spontaneously form by adsorption from an aqueous suspension onto a drop of oil and is subsequently compressed by decreasing the drop volume. The surface pressure is monitored by pendant drop tensiometry throughout the process. Upon compression, the nanoparticles are mechanically forced out of the interface into the aqueous phase. An optical method is developed to measure the nanoparticle area density in situ. We show that desorption occurs at a coverage that corresponds to close packing of the ligand-capped particles, suggesting that ligand-induced repulsion plays a crucial role in this process. © 2011 American Chemical Society

Ideas del infinito, percepciones y conexiones en distintos contextos : el caso de estudiantes con conocimientos previos de cálculo

En este artículo presentamos una investigación que surge de un especial interés por estudiar y explorar el caso del infinito, en su dualidad potencial-actual, en un nivel donde ya se han introducido conceptos formales del cálculo diferencial e integral, y donde empiezan a aparecer interconexiones y confusiones entre la «imagen formal» e «imagen informal» de estos conceptos. El estudio pretende contribuir con el debate de la problemática del infinito e infinitos a nivel universitario. Se enmarca en un estudio cualitativo; el análisis de datos es inductivo y el foco de investigación es de carácter exploratorio, descriptivo e interpretativo. Participaron en el estudio 89 estudiantes con edades comprendidas entre 17 y 25 años.We present a research springing from a special interest in studying and exploring the infinite and its duality power-present, at a level where formal concepts of differential and integral calculus have already been introduced and where there appear interconnections and confusion between the «formal image» and the «informal image» of these concepts. This paper attempts to contribute to the debate of the finite and infinite problems at university level. It is framed within a qualitative study, the analysis of date is inductive and the focus of the research is of an exploratory, descriptive and interpretative kind. Eightynine students aged between 17 and 25 took part in this study