Computing Connection Matrices via Persistence-like Reductions

Connection matrices are a generalization of Morse boundary operators from the classical Morse theory for gradient vector fields. Developing an efficient computational framework for connection matrices is particularly important in the context of a rapidly growing data science that requires new mathematical tools for discrete data. Toward this goal, the classical theory for connection matrices has been adapted to combinatorial frameworks that facilitate computation. We develop an efficient persistence-like algorithm to compute a connection matrix from a given combinatorial (multi) vector field on a simplicial complex. This algorithm requires a single-pass, improving upon a known algorithm that runs an implicit recursion executing two-passes at each level. Overall, the new algorithm is more simple, direct, and efficient than the state-of-the-art. Because of the algorithm's similarity to the persistence algorithm, one may take advantage of various software optimizations from topological data analysis

Properties of neutron doped multicrystalline silicon for solar cells

The technology of neutron transmutation doping of silicon wafers in MARIA nuclear research reactor is described. The studies of the radiation defects performed with positron annihilation confirmed that divacancies dominate in the irradiated material. Thermal treatment of irradiated silicon at 700-1000°C produces void - phosphorus complexes and void aggregates. The resistivity of the samples produced by neutron transmutation doping was found to be uniform within 2.5% limits. The severe reduction of the minority carrier lifetime in irradiated samples was confirmed

Fibre-optic delivery of time and frequency to VLBI station

The quality of Very Long Baseline Interferometry (VLBI) radio observations predominantly relies on precise and ultra-stable time and frequency (T&F) standards, usually hydrogen masers (HM), maintained locally at each VLBI station. Here, we present an operational solution in which the VLBI observations are routinely carried out without use of a local HM, but using remote synchronization via a stabilized, long-distance fibre-optic link. The T&F reference signals, traceable to international atomic timescale (TAI), are delivered to the VLBI station from a dedicated timekeeping laboratory. Moreover, we describe a proof-of-concept experiment where the VLBI station is synchronized to a remote strontium optical lattice clock during the observation.Comment: 8 pages, 8 figures, matches the version published in A&A, section Astronomical instrumentatio

Three-orbital Kondo effect in single quantum dot system with plural electrons

We study the Kondo effect and related transport properties in orbitally degenerate vertical quantum dot systems with plural electrons. Applying the non-crossing approximation to the three-orbital Anderson impurity model with the finite Coulomb interaction and Hund-coupling, we investigate the magnetic-field dependence of the conductance and thermopower. We also introduce an additional orbital splitting to take account of the realistic many-body effect in the vertical quantum dot system. It is clarified how the three-orbital Kondo effect influences the transport properties via the modulation of the Kondo temperature and unitary limit of transport quantities due to the change of the symmetry in the system.Comment: 11 pages, 10 figures, accepted for publication in J. Phys. Soc. Jp

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference