Christopher Duffy

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In higher plants, high light conditions trigger the activation of non-photochemical quenching (NPQ), a process of photoprotective light energy dissipation, via acidification of the chloroplast lumen. Spectral changes occurring in the neoxanthin domain of the major light harvesting antenna complex (LHCII) have previously provided indirect evidence of a(More)
The Critical Zone (CZ) incorporates all aspects of the earth's environment from the vegetation canopy to the bottom of groundwater. CZ researchers target processes that cross timescales from that of water fluxes (milliseconds to decades) to that of the evolution of landforms (thousands to tens of millions of years). Conceptual and numerical models are used(More)
to gain control, men had to "reconceptualize the phenomenon of birth and bring to it a different meaning from the one it had in the hands of the midwives." (p. 21) Oh dear, how did they do that? By declaring the body to be a machine, rather than the natural organism the midwives considered it to be, and then constantly fiddling with the machine in order to(More)
A (m, n)-colored mixed graph is a graph having arcs of m different colors and edges of n different colors. A graph homomorphism of a (m, n)-colored mixed graph G to a (m, n)-colored mixed graph H is a vertex mapping such that if uv is an arc (edge) of color c in G, then f (u)f (v) is also an arc (edge) of color c. The (m, n)-colored mixed chromatic number χ(More)
The major photosystem II antenna complex, LHCII, possesses an intrinsic conformational switch linked to the formation of a photoprotective, excitation-quenching state. Recent solid state NMR experiments revealed that aggregation-induced quenching in (13)C-enriched LHCII from C. reinhardtii is associated with changes to the chemical shifts of three specific(More)
We examine t-colourings of oriented graphs in which, for a fixed integer k ≥ 1, vertices joined by a directed path of length at most k must be assigned different colours. A homomorphism model that extends the ideas of Sherk for the case k = 2 is described. Dichotomy theorems for the complexity of the problem of deciding, for fixed k and t, whether there(More)
The Prisoner's Dilemma Process on a graph G is an iterative process where each vertex, with a fixed strategy (cooperate or defect), plays the game with each of its neighbours. At the end of a round each vertex may change its strategy to that of its neighbour with the highest pay-off. Here we study the spread of cooperative and selfish behaviours on a(More)
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