Characterisation of a track structure imaging detector

The spatial distribution of radiation-induced ionisations in sub-cellular structures plays an important role in the initial formation of radiation damage to biological tissues. Using the nanodosimetry approach, physical characteristics of the track structure can be measured and correlated to DNA damage. In this work, a novel nanodosimeter is presented, which detects positive ions produced by radiation interacting with a gas-sensitive volume in order to obtain a high resolution image of the radiation track structure. The characterisation of the detector prototype was performed and different configurations of the device were tested by varying the detector cathode material and the working gas. Preliminary results show that the ionisation cluster size distribution can be obtained with this approach. Further work is planned to improve the detector efficiency in order to register the complete three-dimensional track structure of ionising radiatio

New and old N=8 superconformal field theories in three dimensions

We show that an infinite family of N=6 d=3 superconformal Chern-Simons-matter theories has hidden N=8 superconformal symmetry and hidden parity on the quantum level. This family of theories is different from the one found by Aharony, Bergman, Jafferis and Maldacena, as well as from the theories constructed by Bagger and Lambert, and Gustavsson. We also test several conjectural dualities between BLG theories and ABJ theories by comparing superconformal indices of these theories.Comment: 16 pages, late

Electrical and magnetic properties of lead-substituted lanthanum ferrimanganites

The temperature dependences of the electrical conductivity, thermopower, and magnetoresistance for single crystals of lead-substituted lanthanum ferrimanganites are investigated. The data on the magnetic microstructure obtained by Mössbauer spectroscopy are analyzed. An inversion of the magnetoresistance sign with an increase in temperature and the giant positive magnetoresistance are found for one of the samples. The magnetoresistance quadratically depends on the field, and its temperature dependence exhibits a maximum. © 2000 MAIK "Nauka/Interperiodica"

Mössbauer studies of sublattice magnetization curves of ferromagnets with several species of characterizing ions

The paper gives a model of a local molecular field describing the magnetization curves in iron garnets separately according to magnetic sublattices. It takes account of the relation between the ion distribution over the lattice sites as well as the values of the local magnetic field and the parameters of the superexchange interaction in such materials. The relations obtained are compared with the data of Mössbauer and NMR spectroscopy. © 1980 Plenum Publishing Corporation

Determination of the parameters characterizing the superexchange interaction in complex ferrite-spinels

A calculation procedure is proposed here for determining the values of exchange parameters, applicable to spinels which contain three kinds of ions in tetrahedral positions and which have an arbitrary distribution of cations. The values of exchange integrals obtained here for ferrites of the manganese-zinc system provide a useful basis for a quantitative interpretation of the spread of Curie-temperature readings in experiments which involve ferrites with the same composition. © 1976 Plenum Publishing Corporation

Index for Three Dimensional Superconformal Field Theories and Its Applications

We review aspects of superconformal indices in three dimension. Three dimensional superconformal indices can be exactly computed by using localization method including monopole contribution, and can be applied to provide evidences for mirror duality, AdS_4/CFT_3 correspondence and global symmetry enhancement of strongly coupled gauge theories. After reviewing, we discuss the possibility of global symmetry enhancement in a finite rank of gauge group.Comment: 14 pages, Proceedings of the Seventh International Conference Quantum Theory and Symmetries (QTS-7) in Prague, Czech Republic, August, 2011; v2: minor modifications, discussion of supersymmetry enhancement of abelian ABJM theory by using an index were adde

Supersymmetry enhancement by monopole operators

We describe a method which allows one to study hidden symmetries in a large class of strongly coupled supersymmetric gauge theories in three dimensions. We apply this method to the ABJM theory and to the infrared limit of N=4 SQCD with adjoint and fundamental matter. We show that the U(N) ABJM model with Chern-Simons level k=1 or k=2 has hidden N=8 supersymmetry. Hidden supersymmetry is also shown to occur in N=4 d=3 SQCD with one fundamental and one adjoint hypermultiplet. The latter theory, as well as the U(N) ABJM theory at k=1, are shown to have a decoupled free sector. This provides evidence that both models are dual to the infrared limit of N=8 U(N) super-Yang-Mills theory.Comment: 29 pages, late

DECODING ERROR CORRECTION CODES USING NEURAL NETWORKS

Developed a back propagation algorithm for artificial neural networks for decoding block codes in the Matlab environment and it trained on all possible codewords for error detection / correction

Dynamic constriction and fission of endoplasmic reticulum membranes by reticulon

The endoplasmic reticulum (ER) is a continuous cell-wide membrane network. Network formation has been associated with proteins producing membrane curvature and fusion, such as reticulons and atlastin. Regulated network fragmentation, occurring in different physiological contexts, is less understood. Here we find that the ER has an embedded fragmentation mechanism based upon the ability of reticulon to produce fission of elongating network branches. In Drosophila, Rtnl1-facilitated fission is counterbalanced by atlastin-driven fusion, with the prevalence of Rtnl1 leading to ER fragmentation. Ectopic expression of Drosophila reticulon in COS-7 cells reveals individual fission events in dynamic ER tubules. Consistently, in vitro analyses show that reticulon produces velocity-dependent constriction of lipid nanotubes leading to stochastic fission via a hemifission mechanism. Fission occurs at elongation rates and pulling force ranges intrinsic to the ER, thus suggesting a principle whereby the dynamic balance between fusion and fission controlling organelle morphology depends on membrane motility