Moscow Institute of Physics and Technology

About: Moscow Institute of Physics and Technology is a education organization based out in Dolgoprudnyy, Russia. It is known for research contribution in the topics: Laser & Large Hadron Collider. The organization has 8594 authors who have published 16968 publications receiving 246551 citations. The organization is also known as: MIPT & Moscow Institute of Physics and Technology (State University).

Random graphs: models and asymptotic characteristics

Abstract: This is a survey of known results related to the asymptotic behaviour of the probabilities of first-order properties of random graphs. The results presented in this paper are concerned with zero-one laws for properties of random graphs. Emphasis is placed on the Erdős-Renyi model of a random graph. Also considered are some generalizations of this model motivated by various problems in the theory of coding and combinatorial geometry. Bibliography: 65 titles.

On the Complexity of Approximating Wasserstein Barycenters

Abstract: We study the complexity of approximating the Wasserstein barycenter of m discrete measures, or histograms of size n, by contrasting two alternative approaches that use entropic regularization. The first approach is based on the Iterative Bregman Projections (IBP) algorithm for which our novel analysis gives a complexity bound proportional to mn/ε to approximate the original non-regularized barycenter. On the other hand, using an approach based on accelerated gradient descent, we obtain a complexity proportional to mn/ε. As a byproduct, we show that the regularization parameter in both approaches has to be proportional to ε, which causes instability of both algorithms when the desired accuracy is high. To overcome this issue, we propose a novel proximal-IBP algorithm, which can be seen as a proximal gradient method, which uses IBP on each iteration to make a proximal step. We also consider the question of scalability of these algorithms using approaches from distributed optimization and show that the first algorithm can be implemented in a centralized distributed setting (master/slave), while the second one is amenable to a more general decentralized distributed setting with an arbitrary network topology.

How Much H2O2 Is Produced by Recombinant D-Amino Acid Oxidase in Mammalian Cells?

Abstract: Yeast D-amino acid oxidase (DAO) can serve as a genetically encoded producer of reactive oxygen species (ROS) in redox signaling studies. However, dynamics of hydrogen peroxide production and its sensitivity to externally added D-alanine (D-Ala) in cells have not been determined. Here we show that DAO, fused to a genetically encoded H2O2 indicator HyPer, can be used for controlled production of ROS in living eukaryotic cells. We found a clear heterogeneity in ROS production dynamics between individual cells. Moreover, different cell lines demonstrated distinct sensitivity to added D-Ala. Finally, by comparing signals generated by the HyPer-DAO fusion protein versus coexpressed HyPer and DAO proteins, we show that the fusion system is more sensitive to hydrogen peroxide production. Our results show the utility of the HyPer-DAO genetically encoded system for redox signaling studies and suggest that H2O2 produced by DAO in the cytoplasm acts locally in close proximity to the enzyme.

Development of nuclear microbattery prototype based on Schottky barrier diamond diodes

Abstract: We designed, fabricated, and tested for the first time a prototype of nuclear micropower battery with an overall active area about 15 cm2 consisted in 130 single cells based on Schottky barrier diamond diodes. Diodes selection for the battery assembly was performed on the basis of I–V curves measurements at electron beam irradiation in SEM. A typical energy conversion efficiency of each cell was about 4–6%. To characterize a battery prototype performance, we carried out photovoltaic measurements using different radioisotopes. Under irradiation by 63Ni source with activity of 5 mCi cm−2, the output power density of 3 nW cm−2 was obtained. Due to large energy loss of the emitted β particles in source itself, the total battery efficiency was only 0.6%. However, with the long-lived 63Ni isotope, this already gives the battery specific energy of about 120 W · hr/kg, comparable with the commercial chemical cells. During experiments with high activity 90Sr–90Y source, no degradation was observed after 1,400 h of the radiation exposure. The maximum output power density of 2.4 µW cm−2 was achieved using 238Pu α source. The results display that synthetic diamond is a highly promising material for nuclear microbattery fabrication. A strategy to further cell optimization is also discussed.

Search for heavy lepton resonances decaying to a Z boson and a lepton in pp collisions at √s=8 TeV with the ATLAS detector

Abstract: A search for heavy leptons decaying to a Z boson and an electron or a muon is presented. The search is based on pp collision data taken at root s = 8TeV by the ATLAS experiment at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 20.3 fb(-1). Three high-transverse-momentum electrons or muons are selected, with two of them required to be consistent with originating from a Z boson decay. No significant excess above Standard Model background predictions is observed, and 95% confidence level limits on the production cross section of high-mass trilepton resonances are derived. The results are interpreted in the context of vector-like lepton and type-III seesaw models. For the vector-like lepton model, most heavy lepton mass values in the range 114-176 GeV are excluded. For the type-III seesaw model, most mass values in the range 100-468 GeV are excluded.