Cut elimination in multifocused linear logic

We study cut elimination for a multifocused variant of full linear logic in the sequent calculus. The multifocused normal form of proofs yields problems that do not appear in a standard focused system, related to the constraints in grouping rule instances in focusing phases. We show that cut elimination can be performed in a sensible way even though the proof requires some specific lemmas to deal with multifocusing phases, and discuss the difficulties arising with cut elimination when considering normal forms of proofs in linear logic.Comment: In Proceedings LINEARITY 2014, arXiv:1502.0441

Multiscale modeling of interaction of alane clusters on Al(111) surfaces: A reactive force field and infrared absorption spectroscopy approach

We have used reactive force field (ReaxFF) to investigate the mechanism of interaction of alanes on Al(111) surface. Our simulations show that, on the Al(111) surface, alanes oligomerize into larger alanes. In addition, from our simulations, adsorption of atomic hydrogen on Al(111) surface leads to the formation of alanes via H-induced etching of aluminum atoms from the surface. The alanes then agglomerate at the step edges forming stringlike conformations. The identification of these stringlike intermediates as a precursor to the bulk hydride phase allows us to explain the loss of resolution in surface IR experiments with increasing hydrogen coverage on single crystal Al(111) surface. This is in excellent agreement with the experimental works of Go et al. [ E. Go, K. Thuermer, and J. E. Reutt-Robey, Surf. Sci. 437, 377 (1999) ]. The mobility of alanes molecules has been studied using molecular dynamics and it is found that the migration energy barrier of Al_(2)H_6 is 2.99 kcal/mol while the prefactor is D_0 = 2.82 × 10^(−3) cm^2/s. We further investigated the interaction between an alane and an aluminum vacancy using classical molecular dynamics simulations. We found that a vacancy acts as a trap for alane, and eventually fractionates/annihilates it. These results show that ReaxFF can be used, in conjunction with ab initio methods, to study complex reactions on surfaces at both ambient and elevated temperature conditions

Revolution and the end of history: Caryl Churchill's Mad Forest

Caryl Churchill’s Mad Forest, written and performed very soon after the Romanian revolution in 1990 and performed both in London and Bucharest, is a dynamic, inter-cultural play that represents a variety of perspectives on the revolutionary events, as well as oscillating between English and Romanian cultural and language coordinates. It has a peculiar topicality in its detailed and specific usages of different aspects of the revolutionary narrative, its sketches of family life before and after the revolution, and the inclusion of the revolution as reported in quasi-documentary-style testimony. The perspective in this article is one that places the play within a framework that thinks through Mad Forest’s relationship to the triumphant, neoliberalist heralding of “the end of history,” most famously argued by Francis Fukuyama in his 1989 article of that name. This discourse gained further confidence from the collapse of Eastern Europe, a collapse that was viewed by proponents of the end-of-history argument as signalling the permanent disintegration of communism and a victory for capitalism. However, Mad Forest is considered here as a play that reflects multiple perspectives on the revolutionary period and, while declining to provide political solutions as such, simultaneously refuses to accede to the implications of the end-of-history argument

The transcriptional response to oxidative stress is part of, but not sufficient for, insulin resistance in adipocytes.

Insulin resistance is a major risk factor for metabolic diseases such as Type 2 diabetes. Although the underlying mechanisms of insulin resistance remain elusive, oxidative stress is a unifying driver by which numerous extrinsic signals and cellular stresses trigger insulin resistance. Consequently, we sought to understand the cellular response to oxidative stress and its role in insulin resistance. Using cultured 3T3-L1 adipocytes, we established a model of physiologically-derived oxidative stress by inhibiting the cycling of glutathione and thioredoxin, which induced insulin resistance as measured by impaired insulin-stimulated 2-deoxyglucose uptake. Using time-resolved transcriptomics, we found > 2000 genes differentially-expressed over 24 hours, with specific metabolic and signalling pathways enriched at different times. We explored this coordination using a knowledge-based hierarchical-clustering approach to generate a temporal transcriptional cascade and identify key transcription factors responding to oxidative stress. This response shared many similarities with changes observed in distinct insulin resistance models. However, an anti-oxidant reversed insulin resistance phenotypically but not transcriptionally, implying that the transcriptional response to oxidative stress is insufficient for insulin resistance. This suggests that the primary site by which oxidative stress impairs insulin action occurs post-transcriptionally, warranting a multi-level 'trans-omic' approach when studying time-resolved responses to cellular perturbations

Numerical Monte Carlo analysis of the influence of pore-scale dispersion on macrodispersion in 2-D heterogeneous porous media

9 p.International audienceWe investigate the influences of pore‐scale dispersion and of larger‐scale permeabilityheterogeneities on the macrodispersion without the molecular diffusion. Permeability followsa lognormal exponentially correlated distribution characterized by its correlation length land its lognormal variance s2. Macrodispersion is evaluated numerically by usingparallel simulations on grids of characteristic size ranging from 200l to 1600l. We noteaLand aTthe pore‐scale longitudinal and transversal dispersivities. For aL/l <10−2andaT/l <10−3, the influence of pore‐scale dispersion on the macrodispersion is smaller than5% of the macrodispersion due only to permeability heterogeneitie

Molecular dynamics simulations of glassy polymers

We review recent results from computer simulation studies of polymer glasses, from chain dynamics around the glass transition temperature Tg to the mechanical behaviour below Tg. These results clearly show that modern computer simulations are able to address and give clear answers to some important issues in the field, in spite of the obvious limitations in terms of length and time scales. In the present review we discuss the cooling rate effects, and dynamic slowing down of different relaxation processes when approaching Tg for both model and chemistry-specific polymer glasses. The impact of geometric confinement on the glass transition is discussed in detail. We also show that computer simulations are very useful tools to study structure and mechanical response of glassy polymers. The influence of large deformations on mechanical behaviour of polymer glasses in general, and strain hardening effect in particular are reviewed. Finally, we suggest some directions for future research, which we believe will be soon within the capabilities of state of the art computer simulations, and correspond to problems of fundamental interest.Comment: To apear in "Soft Matter