Quantal analysis of long-term potentiation of combined neuronal postsynaptic potentials on hippocampal slices in vitro.

10.1007/BF0105247

Antiproton-Hydrogen annihilation at sub-kelvin temperatures

The main properties of the interaction of ultra low-energy antiprotons ($E\le10^{-6}$ a.u.) with atomic hydrogen are established. They include the elastic and inelastic cross sections and Protonium (Pn) formation spectrum. The inverse Auger process ($Pn+e \to H+\bar{p}$) is taken into account in the framework of an unitary coupled-channels model. The annihilation cross-section is found to be several times smaller than the predictions made by the black sphere absorption models. A family of $\bar{p}H$ nearthreshold metastable states is predicited. The dependence of Protonium formation probability on the position of such nearthreshold S-matrix singularities is analysed. An estimation for the $H\bar{H}$ annihilation cross section is obtained.Comment: latex.tar.gz file, 22 pages, 9 figure

Whispering Gallery States of Antihydrogen

We study theoretically interference of the long-living quasistationary quantum states of antihydrogen atoms, localized near a concave material surface. Such states are an antimatter analog of the whispering gallery states of neutrons and matter atoms, and similar to the whispering gallery modes of sound and electro-magnetic waves. Quantum states of antihydrogen are formed by the combined effect of quantum reflection from van der Waals/Casimir-Polder (vdW/CP) potential of the surface and the centrifugal potential. We point out a method for precision studies of quantum reflection of antiatoms from vdW/CP potential; this method uses interference of the whispering gallery states of antihydrogen.Comment: 13 pages 7 figure

Symbionts on the Brain: How Wolbachia Is Strictly Corralled in Some Neotropical Drosophila spp.

Wolbachia is a heritable alphaproteobacterial symbiont of arthropods and nematodes, famous for its repertoire of host manipulations, including cytoplasmic incompatibility. To be vertically transmitted, Wolbachia must efficiently colonize the female germ line, although somatic tissues outside the gonads are also infected. In Drosophila spp., Wolbachia is usually distributed systemically in multiple regions of the adult fly, but in some neotropical hosts, Wolbachia's only somatic niches are cerebral bacteriocyte-like structures and the ovarian follicle cells. In their recent article, Strunov and colleagues (A. Strunov, K. Schmidt, M. Kapun, and W. J. Miller. mBio 13:e03863-21, 2022, https://doi.org/10.1128/mbio.03863-21) compared the development of Drosophila spp. with systemic or restricted infections and demonstrated that the restricted pattern is determined in early embryogenesis by an apparently novel autophagic process, involving intimate interactions of Wolbachia with the endoplasmic reticulum. This work has implications not only for the evolution of neotropical Drosophila spp. but also for our understanding of how Wolbachia infections are controlled in other native or artificial hosts

Randomized Matrix Decompositions Using R

Matrix decompositions are fundamental tools in the area of applied mathematics, statistical computing, and machine learning. In particular, low-rank matrix decompositions are vital, and widely used for data analysis, dimensionality reduction, and data compression. Massive datasets, however, pose a computational challenge for traditional algorithms, placing significant constraints on both memory and processing power. Recently, the powerful concept of randomness has been introduced as a strategy to ease the computational load. The essential idea of probabilistic algorithms is to employ some amount of randomness in order to derive a smaller matrix from a high-dimensional data matrix. The smaller matrix is then used to compute the desired low-rank approximation. Such algorithms are shown to be computationally efficient for approximating matrices with low-rank structure. We present the R package rsvd, and provide a tutorial introduction to randomized matrix decompositions. Specifically, randomized routines for the singular value decomposition, (robust) principal component analysis, interpolative decomposition, and CUR decomposition are discussed. Several examples demonstrate the routines, and show the computational advantage over other methods implemented in R

The VoTe room temperature H216O line list up to 25000 cm-1

A preliminary version of the line list of dipole-allowed transition of the water molecule is presented. The line lists is created on the basis of VoTe calculations (Voronin, Tennyson et al. in preparation). The cut-of values used for this line list are: 25000 cm-1 in wave number and 10-30 cm/molecule at T=296 K in intensity. Calculated line-lists are available on the site ftp://ftp.iao.ru/pub/VTT/VoTe/

On the pulse pneumatic transportation of metal radioactive waste materials at atomic electric power stations

Abstract A problem of metal particles movement in a tube under action of a pulse gas flow was numerically and experimentally solved. Comparison of computational and experimental data was carried out. On the basis of researches the optimum characteristics of the work of pulse pneumatic transportation of metal radioactive waste materials are determined. Modeling was performed within the framework of model of non-stationary two-dimensional motion of ideal compressible media on the basis of laws of conservation of mass, pulse and energy in case of axial symmetry. The thermodynamic flow field has been computed both in gas and solid phases. Processes of particles mutual interactions, coalescence, fragmentation, interaction with a tube walls and motion have been investigated in detail. Interface borders have been considered as contact discontinuity surfaces, where a condition of a continuity of normal to the surface component of a flow velocity vector and the continuity of normal component of tension tensor were satisfied. Modeling was performed numerically on the basis of the method of individual particles. The comparison of the computational and experimental data confirms the reliability of numerical algorithm. The optimum pipeline parameters (optimum nozzle diameter is 37 mm, pressure of gas in receiver chamber is about 8 MPa) are determined, at which the effective pulse cleaning of pipelines from metal wastes with the least expenses is possible. It was found that series of pulses is more effective mode of transportation than a single pulse, having similar total power