A second look at a recent algebraic proof of nonlocality

We reply to M. Jones' criticisms of our proof that factorable stochastic hidden-variable theories are inconsistent with GHZ-style strict correlations predicted by quantum mechanics. We endorse Jones' clarifications of our definitions of the setsM and _TF. And we reply to his main criticism by invoking one additional locality-motivated assumption. Further, we show how this additional assumption can be weakened while preserving our proof's validity.1. Ironically, a draft version of our paper (March, 1990) used this assumption, and discussed its motivation and weakening. But we were then misled into thinking it unnecessary: So all credit to Jones for seeing the wood for the trees!2. This new assumption, AI (see below), alsorestores the link between TF, the strict correlations, and Shimony'sTF, which is severed by Jones' criticism (as he notes—cf. Ref. 1, pp. 162, 165 for our original claim of a link). Thus the correct result is that if TF, the strict correlations,and AI hold in any state, then so doesTF.     

Mantel's theorem for random hypergraphs

A classical result in extremal graph theory is Mantel's Theorem, which states that every maximum triangle‐free subgraph of K_n is bipartite. A sparse version of Mantel's Theorem is that, for sufficiently large p, every maximum triangle‐free subgraph of G(n, p) is w.h.p. bipartite. Recently, DeMarco and Kahn proved this for for some constant K, and apart from the value of the constant this bound is best possible. We study an extremal problem of this type in random hypergraphs. Denote by F₅, which is sometimes called the generalized triangle, the 3‐uniform hypergraph with vertex set and edge set . One of the first results in extremal hypergraph theory is by Frankl and Füredi, who proved that the maximum 3‐uniform hypergraph on n vertices containing no copy of F₅ is tripartite for n > 3000. A natural question is for what p is every maximum F₅‐free subhypergraph of w.h.p. tripartite. We show this holds for for some constant K and does not hold for . © 2016 Wiley Periodicals, Inc. Random Struct. Alg., 48, 641–654, 2016     

Amyloidogenic Protein–Membrane Interactions: Mechanistic Insight from Model Systems

The toxicity of amyloid‐forming proteins is correlated with their interactions with cell membranes. Binding events between amyloidogenic proteins and membranes result in mutally disruptive structural perturbations, which are associated with toxicity. Membrane surfaces promote the conversion of amyloid‐forming proteins into toxic aggregates, and amyloidogenic proteins, in turn, compromise the structural integrity of the cell membrane. Recent studies with artificial model membranes have highlighted the striking resemblance of the mechanisms of membrane permeabilization of amyloid‐forming proteins to those of pore‐forming toxins and antimicrobial peptides.     

A comparison of hybrid density functional theory with photoemission of surface oxides of δ-plutonium

We carried out high resolution photoelectron spectroscopy (PES) studies on a gallium stabilized δ-phase plutonium sample cleaned by laser ablation and gas dosed with O₂. The measurements were made at a sample temperature of 77 K with an overall instrument resolution of 60 meV. At this temperature the PES strongly favor an idealized model of Pu₂O₃ growth on the metal surface followed by PuO₂ growth on the Pu₂O₃. These experimental results provide an excellent benchmark for a new generation of hybrid density functional calculations that have been used to model a defective plutonium dioxide lattice. The hybrid functional predicts an insulating ground state. This is of paramount importance for the study of actinide oxides because the conventional density functional theory approaches predict them to be metals, when in fact they are insulators with significant band gaps. The calculated density of states for PuO₂ and Pu₂O₃ agree reasonably well with the experimental data.     

Cyclic plate bearing tests

A series of circular and square plate-bearing tests are reported, the load-displacement curves for which can be fitted quite closely by a three parameter curve of modified exponential form. The characteristics features of the response of such plates to loading and unloading cycles are then demonstrated and it is shown that their behaviour can be accurately modelled by a simple modification of the first-load response equation which requires three further parameters to be introduced.The six parameters, from which the cyclic load behaviour of plates of any size can be predicted, can be determined from two in situ tests: a conventional plate test and a single-load-level cyclic plate test.     

A Topos Perspective on the Kochen-Specker Theorem II. Conceptual Aspects and Classical Analogues

In a previous paper, we proposed assigning asthe value of a physical quantity in quantum theory acertain kind of set (a sieve) of quantities that arefunctions of the given quantity. The motivation was in part physical — such a valuationilluminates the Kochen–Specker theorem — andin part mathematical — the valuation arisesnaturally in the topos theory of presheaves. This paperdiscusses the conceptual aspects of this proposal. We also undertake two othertasks. First, we explain how the proposed valuationscould arise much more generally than just in quantumphysics; in particular, they arise as naturally in classical physics. Second, we give anothermotivation for such valuations (that applies equally toclassical and quantum physics). This arises fromapplying to propositions about the values of physical quantities some general axioms governingpartial truth for any kind of proposition.     

A structural interpretation of the two components governing the kinetic fragility from the example of interpenetrated polymer networks

Kinetic fragility and cooperativity length, two major characteristics of the relaxation dynamics at the glass transition, are, respectively, investigated by dynamic mechanical analysis and modulated temperature differential scanning calorimetry in a series of interpenetrated polymer networks based on acrylate and epoxy systems. The relaxation dynamics are impacted by two variables: the rigidity of the network, and the structural heterogeneity resulting from blending. However, the fragility and the cooperativity do not vary similarly. The glass transition progressively broadens as the mass fractions of acrylate and epoxy become equivalent, leading to a strong decrease in cooperativity. On the other hand, under the same conditions, the fragility transitions between the lower value of pure acrylate and the higher value of pure epoxy. This divergence helps concluding that the variations in the temperature dependence of the relaxation time are not purely related to the more or less cooperative nature of the glass transition. By splitting the fragility index in a volume contribution and an energetic contribution, it is shown that the contribution of cooperativity to the variations of the relaxation time with temperature is increased under two structural conditions: low backbone rigidity and high intermolecular interactions. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1393–1403     

FtsZ Reorganization Facilitates Deformation of Giant Vesicles in Microfluidic Traps**

The geometry of reaction compartments can affect the local outcome of interface-restricted reactions. Giant unilamellar vesicles (GUVs) are commonly used to generate cell-sized, membrane-bound reaction compartments, which are, however, always spherical. Herein, we report the development of a microfluidic chip to trap and reversibly deform GUVs into cigar-like shapes. When trapping and elongating GUVs that contain the primary protein of the bacterial Z ring, FtsZ, we find that membrane-bound FtsZ filaments align preferentially with the short GUV axis. When GUVs are released from this confinement and membrane tension is relaxed, FtsZ reorganizes reversibly from filaments into dynamic rings that stabilize membrane protrusions; a process that allows reversible GUV deformation. We conclude that microfluidic traps are useful for manipulating both geometry and tension of GUVs, and for investigating how both affect the outcome of spatially-sensitive reactions inside them, such as that of protein self-organization.