ERC FUNDED PROJECTS

The advent of high-power laser systems in the past two decades has opened a new field of research where astrophysical environments can be scaled down to laboratory dimensions, yet preserving the essential physics. This is due to the invariance of the equations of ideal magneto-hydrodynamics (MHD) to a class of self-similar transformations. In this proposal, we will apply these scaling laws to investigate the dynamics of the high Mach number shocks arising during the formation of the large-scale structure of the Universe. Although at the beginning of cosmic evolution matter was nearly homogenously distributed, today, as a result of gravitational instability, it forms a web-like structure made of filaments and clusters. Gas continues to accrete supersonically onto these collapsed structures, thus producing high Mach number shocks. It has been recently proposed that generation of magnetic fields can occur at these cosmic shocks on a cosmologically fast timescale via a Weibel-like instability, thus providing an appealing explanation to the ubiquitous magnetization of the Universe. Our proposal will thus provide the first experimental evidence of such mechanisms. We plan to measure the self-generated magnetic fields from laboratory shock waves using a novel combination of electron deflectometry, Faraday rotation measurements using THz lasers, and dB/dt probes. The proposed investigation on the generation of magnetic fields at shocks via plasma instabilities bears important general consequences. First, it will shed light on the origin of cosmic magnetic fields. Second, it would have a tremendous impact on one of the greatest puzzles of high energy astrophysics, the origin of Ultra High Energy Cosmic Rays. We plan to assess the role of charged particle acceleration via collisionless shocks in the amplification of the magnetic field as well as measure the spectrum of such accelerated particles. The experimental work will be carried both at Oxford U and at laser facilities.

1 119 690 €

Start date: 2010-12-01, End date: 2015-11-30

The project aims to bring about a paradigm shift in our understanding of how the ancients conceived of the universe and its contents over a period of 9 centuries, 600 BC to 300 AD. The driving research hypothesis is that the sole elementary building blocks of nearly all ancient ontologies are powers, from which all there is in the universe is built. Powers are relational properties which are directed towards an end (e.g. the power to heat); thus a world of powers is structured in a web of causal relations. What is revolutionary about such a world is that there is only structure in it; hence, causal structuralist ontologies underlie object-metaphysics or process-metaphysics, and worlds of being and becoming, supplying structures from which objects and processes are derived. Yet such ontologies have never been investigated about ancient thought. The project’s topic is new: ancient causal structuralism; the speciality is novel too, requiring targeted training of a team of post-doc researchers which will be provided by the applicant and collaborators. The innovativeness of the methodology consists in training ancient philosophy researchers to discern and identify formal aspects of ontologies at the very roots of human rationality – discerning how the ancients built everything out of power structures. The paradigm shift will generate new knowledge and understanding about the ancient accounts of the world; provide a heuristic vantage point for redrafting the map of the intellectual influences between ancient thinkers; stimulate fruitful debate; and inspire new insights into ancient thought that are literally unthinkable at present. Cognate disciplines that will be affected by the paradigm shift are such as: history of physics; of mathematics; of theology; ancient anthropology.

1 228 581 €

Start date: 2011-04-01, End date: 2016-03-31

Cellular processes such as cytokinesis, the budding of enveloped retrovirus (e.g. HIV-1), and multivesicular biogenesis have direct links to several human diseases including carcinogenesis and neuro-degeration etc. While seemingly unrelated, these processes all involve membrane abscission for generating two newly formed membrane bound structures - a process aided by the cytosolic proteins collectively termed ESCRT-III. Understanding these processes for therapeutic intervention has so far focused on identification of the factors involved, their structures, and the interactions between them. However, given that membrane-abcission is the key event in all these processes, the mechanics of membrane scission cannot be neglected. Due to fast and highly localised transformations, protein mediated membrane remodelling in general has proven difficult for quantitative mechanistic scrutiny (perhaps with the single exception of dynamin which, unlike the ESCRT-III, acts from the outside of a membrane neck). In humans ESCRT-III members are called CHMPs. Major advances have been recently made in (i) determination of polymeric structures formed by human (yeast) CHMP4 (Snf7), CHMP3 (vps24) and CHMP2A; (ii) membrane splitting activity has been attributed to the sequential binding of the yeast proteins vps20 (CHMP6), Snf7 and vps24, (iii) vps2 (CHMP2), which binds vps24, recruits a AAA ATPAse vps4 which then recycles the membrane bound ESCRT-III. Several models have since been proposed where protein polymers constricting the membrane neck for fission is the common theme. However, there is considerable debate over the essential molecular mechanism of the process. Therefore, I will address: 1. How do CHMP2, 3, 4 and 6 assemblies form on membranes and dissociate in a VPS4 dependent manner? 2. What are the structures, composition and direction of growth of ESCRT-III assemblies as they mature on lipid membranes? 3. Since ESCRT-III polymer must form through the central pore of a membrane tubule, thereby posing a steric hindrance for fusion, how does pore closure followed by scission take place? 4. As CHMPs are predominantly cytosolic, how do their binding partners such as VPS4, AMSH (deubiquitin isopeptidase), and Alix (adaptor molecule) get selectively targeted to the membrane-bound fraction of CHMPs to exert their membrane proximal function? Answering the posed questions will not only advance our understanding of HIV egress from cells, it may also help open new therapeutic intervention points for several ESCRT-III related dysfunction. These studies will further form the basis for in vivo investigation of the mechanism by which ESCRT-III functions.

1 499 655 €

Start date: 2010-10-01, End date: 2016-01-31

The aim is to integrate photosynthetic solar energy conversion and synthesis of volatile engine-ready transport fuel in a single photobiological process. The focus is placed on the construction of phototrophic model systems for synthesis of the short-chain alkane propane (C3H8). Propane can be used in existing engines without further chemical conversion and can be easily recovered from the production process without destructive harvesting and extraction. However, no commercial biological production process exists and there is no known metabolic pathway for short-chain alkane biosynthesis. The intention is to construct a synthetic pathway for propane biosynthesis. In order to facilitate the construction, alkane biosynthetic pathways are studied in detail and genes encoding key-enzymes are isolated from diverse organisms. In order to directly capture solar energy to drive fuel biosynthesis, the synthetic pathways are assembled in the photosynthetic model organism Synechocystis sp. PCC 6803. Native host metabolism is thereafter optimized to maximize the delivery of metabolic precursors and reducing energy to the synthetic pathways. In order to facilitate strain construction, cyanobacterial host strains are optimized for metabolic engineering and hydrocarbon fuel biosynthesis. The project has the ultimate aim to generate cyanobacteria strains that synthesize short-chain alkane using only light, CO2 and H2O as substrate. The project has a clear applied target with high potential for socio-economical impact and a high risk / high gain character.

916 120 €

Start date: 2011-01-01, End date: 2015-12-31