Re-thinking the Legacy 2012: The Olympics as commodity and gift

This paper opens discussion about the nature of Olympic ‘legacy’ and articulates a contradiction in the way ‘legacy’ is conceived - between ’gift’ and ’commodity’ (Mauss 1954).The The paper argues that establishing working definitions and parameters for ‘legacy’ is a difficult task. Defining ‘legacy’ is problematic especially if conceived as an entirely predictable or measurable set of objectives. Indeed, the definition of ‘legacy’ is partly constitutive of the legacy itself, a component of achievements that the city might make. Such a ‘legacy definition’ will become a functional term in the complex planning and evolving conceptions underpinning urban change for some time—if successfully negotiated and if governable. As such, ‘legacy’, and the activities and values entailed to it, can come to provide a catalytic ‘vocabulary of motives’ and a legitimating discourse enabling politicians, communities and their individual representatives to justify investments, evolving strategies and activities connected to and connecting developmental gains in a more or less healthy fashion. It is because of this that legacy and its various meanings come to matter

Covalently Binding the Photosystem I to Carbon Nanotubes

We present a chemical route to covalently couple the photosystem I (PS I) to carbon nanotubes (CNTs). Small linker molecules are used to connect the PS I to the CNTs. Hybrid systems, consisting of CNTs and the PS I, promise new photo-induced transport phenomena due to the outstanding optoelectronic properties of the robust cyanobacteria membrane protein PS I

A modular DNA signal translator for the controlled release of a protein by an aptamer

Owing to the intimate linkage of sequence and structure in nucleic acids, DNA is an extremely attractive molecule for the development of molecular devices, in particular when a combination of information processing and chemomechanical tasks is desired. Many of the previously demonstrated devices are driven by hybridization between DNA ‘effector’ strands and specific recognition sequences on the device. For applications it is of great interest to link several of such molecular devices together within artificial reaction cascades. Often it will not be possible to choose DNA sequences freely, e.g. when functional nucleic acids such as aptamers are used. In such cases translation of an arbitrary ‘input’ sequence into a desired effector sequence may be required. Here we demonstrate a molecular ‘translator’ for information encoded in DNA and show how it can be used to control the release of a protein by an aptamer using an arbitrarily chosen DNA input strand. The function of the translator is based on branch migration and the action of the endonuclease FokI. The modular design of the translator facilitates the adaptation of the device to various input or output sequences

Weber and Simmel’s philosophical and political stances : a dialogue in three acts

This article is an imagined dialogue between Weber and Simmel which makes a modest use of some of the resources of theatrical play in order to provide an overall portrait of both thinkers and to bring their thought to bear on our present. The dialogue consists of three acts focused on three central problematics in as many critical moments in Weber and Simmel’s lives: Act I takes place during the preparations for the first conference of the German Sociological Association and thus deals with the constitution of sociology as a socio-cultural science. Act II takes place amidst the First World War and its theme is evidently politics. Finally, Act III, where our two characters correspond instead of maintaining a face-to-face dialogue, is situated towards the end of the war and focuses on the attitude to life and indeed to death, as Simmel’s tragic yet admirable death takes place then. A brief introduction explains how we tried to use the possibilities of the dialogical form to expound Weber’s and Simmel’s thought, to compel them to confront their own blind spots and ‘unthoughts’, as well as to explore new ways of teaching the classics and transmitting their thought

Nanopore Force Spectroscopy of Aptamer–Ligand Complexes

AbstractThe stability of aptamer–ligand complexes is probed in nanopore-based dynamic force spectroscopy experiments. Specifically, the ATP-binding aptamer is investigated using a backward translocation technique, in which the molecules are initially pulled through an α-hemolysin nanopore from the cis to the trans side of a lipid bilayer membrane, allowed to refold and interact with their target, and then translocated back in the trans–cis direction. From these experiments, the distribution of bound and unbound complexes is determined, which in turn allows determination of the dissociation constant Kd ≈ 0.1 mM of the aptamer and of voltage-dependent unfolding rates. The experiments also reveal differences in binding of the aptamer to AMP, ADP, or ATP ligands. Investigation of an aptamer variant with a stabilized ATP-binding site indicates fast conformational switching of the original aptamer before ATP binding. Nanopore force spectroscopy is also used to study binding of the thrombin-binding aptamer to its target. To detect aptamer–target interactions in this case, the stability of the ligand-free aptamer—containing G-quadruplexes—is tuned via the potassium content of the buffer. Although the presence of thrombin was detected, limitations of the method for aptamers with strong secondary structures and complexes with nanomolar Kd were identified

Statistics of conductance oscillations of a quantum dot in the Coulomb-blockade regime

The fluctuations and the distribution of the conductance peak spacings of a quantum dot in the Coulomb-blockade regime are studied and compared with the predictions of random matrix theory (RMT). The experimental data were obtained in transport measurements performed on a semiconductor quantum dot fabricated in a GaAs-AlGaAs heterostructure. It is found that the fluctuations in the peak spacings are considerably larger than the mean level spacing in the quantum dot. The distribution of the spacings appears Gaussian both for zero and for non-zero magnetic field and deviates strongly from the RMT-predictions.Comment: 7 pages, 4 figure

Diversity in the dynamical behaviour of a compartmentalized programmable biochemical oscillator

In vitro compartmentalization of biochemical reaction networks is a crucial step towards engineering artificial cell-scale devices and systems. At this scale the dynamics of molecular systems becomes stochastic, which introduces several engineering challenges and opportunities. Here we study a programmable transcriptional oscillator system that is compartmentalized into microemulsion droplets with volumes between 33 fl and 16 pl. Simultaneous measurement of large populations of droplets reveals major variations in the amplitude, frequency and damping of the oscillations. Variability increases for smaller droplets and depends on the operating point of the oscillator. Rather than reflecting the stochastic kinetics of the chemical reaction network itself, the variability can be attributed to the statistical variation of reactant concentrations created during their partitioning into droplets. We anticipate that robustness to partitioning variability will be a critical challenge for engineering cell-scale systems, and that highly parallel time-series acquisition from microemulsion droplets will become a key tool for characterization of stochastic circuit function.1172sciescopu

Cultures of caste and rural development in the social network of a south Indian village

Cultures of caste in much of rural India have become entangled with institutions of rural development. In community-driven development, emphasis on “local resource persons” and “community spokespersons” has created new opportunities for brokerage and patronage within some villages, which interact with existing forms of authority and community afforded by caste identity and intra-caste headmanship. In this article, we study how these entangled cultures of caste and development translate into social network structures using data on friendship ties from a south Indian village. We find that although caste continues to be important in shaping community structures and leadership in the village’s network, its influence varies across different communities. This fluidity of caste’s influence on community network structures is argued to be the result of multiple distinct yet partially overlapping cultural-political forces, which include sharedness afforded by caste identity and new forms of difference and inequality effected through rural development