Cosmic ray driven dynamo in galactic disks. A parameter study

We present a parameter study of the magnetohydrodynamical dynamo driven by cosmic rays in the interstellar medium (ISM) focusing on the efficiency of magnetic field amplification and the issue of energy equipartition between magnetic, kinetic and cosmic ray (CR) energies. We perform numerical CR-MHD simulations of the ISM using the extended version of ZEUS-3D code in the shearing box approximation and taking into account the presence of Ohmic resistivity, tidal forces and vertical disk gravity. CRs are supplied in randomly distributed supernova (SN) remnants and are described by the diffusion-advection equation, which incorporates an anisotropic diffusion tensor. The azimuthal magnetic flux and total magnetic energy are amplified depending on a particular choice of model parameters. We find that the most favorable conditions for magnetic field amplification correspond to magnetic diffusivity of the order of 3\times 10^{25} \cm^2\s^{-1}, SN rates close to those observed in the Milky Way, periodic SN activity corresponding to spiral arms, and highly anisotropic and field-aligned CR diffusion. The rate of magnetic field amplification is relatively insensitive to the magnitude of SN rates in a rage of spanning 10% up to 100% of realistic values. The timescale of magnetic field amplification in the most favorable conditions is 150 Myr, at galactocentric radius equal to 5 kpc. The final magnetic field energies fluctuate near equipartition with the gas kinetic energy. In all models CR energy exceeds the equipartition values by a least an order of magnitude, in contrary to the expected equipartition. We suggest that the excess of cosmic rays can be attributed to the fact that the shearing-box does not permit cosmic rays to leave the system along the horizontal magnetic field.Comment: 12 papges, 11 figures, accepted for publication in Astronomy and Astrophysic

Predictive compensation of thermal deformations of ball screws in CNC machines using neural networks

Potreba za povećanjem točnosti pozicioniranja servo-pogona bila je poticaj za istraživanje nove metode bez senzora za kompenzaciju toplinskih deformiranja kuglastih vijaka, koja će omogućiti predvidivu kompenzaciju izduženja takvih vijaka na temelju prikupljenih podataka. Razvijeni su modeli za predvidivu kompenzaciju toplinskih deformiranja kuglastih vijaka u CNC strojevima, u obliku jednosmjernih višeslojnih neuronskih mreža s unatražnim rasprostiranjem greške (MLP), neuronskih mreža s funkcijom radijalne baze (RBF) i Kohonen mreža. Razvijene su neuronske mreže s različitim strukturama i parametrima učenja, i te su se mreže uspoređivale. Modeli su se procjenjivali prema učinkovitosti mreža. Modeli su se ispitivali s realnim podacima.The need to improve the accuracy of positioning of a servo-drive was the stimulus for research on a new sensorless method for compensation of thermal deformations of ball screws, enabling predictive compensation of the elongation of such a screw based on historical data. Models have been developed for the predictive compensation of thermal deformations of ball screws in CNC machines, in the form of single-directional multi-layered neural networks with error back-propagation (MLP), radial basis function neural networks (RBF) and Kohonen networks. Neural networks were developed with different structures and learning parameters, and these networks were compared. Models were evaluated in terms of the effectiveness of operation of the networks. The models were tested on real data

Discussion of the Electromotive Force Terms in the Model of Parker-unstable Galactic Disks with Cosmic Rays and Shear

We analyze the electromotive force (EMF) terms and basic assumptions of the linear and nonlinear dynamo theories in our three-dimensional (3D) numerical model of the Parker instability with cosmic rays and shear in a galactic disk. We also apply the well known prescriptions of the EMF obtained by the nonlinear dynamo theory (Blackman & Field 2002 and Kleeorin et al. 2003) to check if the EMF reconstructed from their prescriptions corresponds to the EMF obtained directly from our numerical models. We show that our modeled EMF is fully nonlinear and it is not possible to apply any of the considered nonlinear dynamo approximations due to the fact that the conditions for the scale separation are not fulfilled.Comment: 15 pages, 12 figure

Global galactic dynamo driven by cosmic-rays and exploding magnetized stars

We report first results of first global galactic-scale CR-MHD simulations of cosmic-ray-driven dynamo. We investigate the dynamics of magnetized interstellar medium (ISM), which is dynamically coupled with the cosmic-ray (CR) gas. We assume that exploding stars deposit small-scale, randomly oriented, dipolar magnetic fields into the differentially rotating ISM, together with a portion of cosmic rays, accelerated in supernova shocks. We conduct numerical simulations with the aid of a new parallel MHD code PIERNIK. We find that the initial magnetization of galactic disks by exploding magnetized stars forms a favourable conditions for the cosmic-ray-driven dynamo. We demonstrate that dipolar magnetic fields supplied on small SN-remnant scales, can be amplified exponentially, by the CR-driven dynamo, to the present equipartition values, and transformed simultaneously to large galactic-scales. The resulting magnetic field structure in an evolved galaxy appears spiral in the face-on view and reveals the so called X-shaped structure in the edge-on view.Comment: 11 pages, 4 figure

The analgesic efficiency of transversus abdominis plane (TAP) block after caesarean delivery

Objectives: The ultrasound-guided transversus abdominis plane (TAP) block is a supporting method of pain relief after different types of surgical and gynecological procedures. The aim of the present study was to evaluate the analgesic effects of the TAP-block in patients undergoing caesarean section. Material and methods: 88 women undergoing elective caesarean section under spinal anaesthesia were prospectively randomized into two groups. In the first group, an ultrasound-guided bilateral TAP block was performed using 40 mL 0.25% bupivacaine, while the second group was treated without a regional nerve block. Both groups received a standard analgesia protocol with intravenous paracetamol administered every 6 hours and intravenous tramadol on-demand, delivered using the Patient Controlled Analgesia (PCA) method. Pain intensity was assessed according to the visual analogue scale (VAS) directly after the TAP block and at 3, 6 and 12 hours postoperatively. Any patient complaints and side-effects during the postoperative period were recorded. Results: The TAP block resulted in a significant reduction of pain intensity using the visual analogue scale after 3, 6 and 12 hours (p < 0.05) and a significant decrease in tramadol administration (p < 0.05) during the first 12 hours postoperatively. No significant differences in the heart rate and blood pressure were noted between groups (p > 0.05). There were no complications related to the TAP block. Conclusions: The TAP block is a safe and effective adjunctive method of pain relief after caesarean delivery

Cosmic ray driven dynamo in barred and ringed galaxies

We study the global evolution of the magnetic field and interstellar medium (ISM) of the barred and ringed galaxies in the presence of non-axisymmetric components of the potential, i.e. the bar and/or the oval perturbations. The magnetohydrodynamical dynamo is driven by cosmic rays (CR), which are continuously supplied to the disk by supernova (SN) remnants. Additionally, weak, dipolar and randomly oriented magnetic field is injected to the galactic disk during SN explosions. To compare our results directly with the observed properties of galaxies we construct realistic maps of high-frequency polarized radio emission. The main result is that CR driven dynamo can amplify weak magnetic fields up to few $\mu$G within few Gyr in barred and ringed galaxies. What is more, the modelled magnetic field configuration resembles maps of the polarized intensity observed in barred and ringed galaxies

Genetic predisposition to papillary thyroid cancer

Około 5% zróżnicowanych raków tarczycy wykazuje predyspozycję dziedziczną. Dziedziczny nierdzeniasty rak tarczycy może występować jako składowa niektórych dziedzicznych zespołów nowotworowych, na przykład rodzinnej polipowatości jelit oraz jako rodzinny zróżnicowany rak tarczycy (FNMTC, familial non-medullary thyroid cancer), gdzie najczęściej obserwuje się raka brodawkowatego. Choć predyspozycja dziedziczna do nierdzeniastych raków tarczycy jest dobrze znana, to jednak geny warunkujące jej występowanie nie zostały jeszcze poznane. Wykonane jak dotąd badania zidentyfikowały kilka loci - 1q21, 6q22, 8p23.1-p22 oraz 8q24, jednak wyniki te nie zawsze były jednoznaczne. W niniejszej pracy omówiono rezultaty badań sprzężenia oraz ostatnio uzyskane wyniki badań związku całego genomu (GWAS, genome wide association study) wykonano przez badania polimorfizmu pojedynczego nukleotydu (SNP, single nucleotide polymorphism) z wykorzystaniem techniki mikromacierzy wysokiej gęstości. (Endokrynol Pol 2010; 61 (5): 486-489)Approximately 5% of differentiated thyroid cancers are hereditary. Hereditary non-medullary thyroid cancer may occur as a minor component of familial cancer syndromes (e.g. familial adenomatous polyposis) or as a primary feature (familial non-medullary thyroid cancer [FNMTC]). Among FNMTC, PTC is the most common. Although a hereditary predisposition to non-medullary thyroid cancer is well established, the susceptibility genes are poorly known. Up to now, by linkage analysis using microsatellite markers, several putative loci have been described - 1q21, 6q22, 8p23.1-p22, and 8q24; however, validation studies have been unsuccessful. In the present review we discuss the results of linkage analysis and the most recent results of genome wide association studies (GWAS) with high resolution SNP (single nucleotide polymorphism) arrays. (Pol J Endocrinol 2010; 61 (5): 486-489

The late Jurassic-Palaeogene carbonate platforms in the Outer Western Carpathian Tethys - A regional overview

The present work focuses on palaeogeographic reconstruction of shallow-water carbonate deposition in the Outer Western Carpathian Tethys. Platform deposits are preserved only as a component of turbidites and olistostromes, and reconstructions of these platforms are based on clastic material redistributed into slopes and deep basins and occurring among the Outer Carpathian nappes. Similar platforms were also present on the Tethys margins. These reconstructions were performed using the global models of plate tectonics. Several ridges covered by carbonate platforms developed in that area during the latest Jurassic-Palaeogene times. Three main shallow-water facies associations-Stramberk, Urgonian, and Lithothamnion-bryozoan-could be distinguished. The Tithonian-lowermost Cretaceous Stramberk facies is related to early, synrift-postrift stage of the development of the Silesian Domain. Facies that are diversified, narrow, shallow-water platforms, rich in corals, sponges, green algae, echinoderms, foraminifera, microencrusters, and microbes are typical of this stage. The Urgonian facies developed mainly on the south margin of the Outer Carpathian basins and is characterised by organodetritic limestones built of bivalves (including rudists), larger benthic foraminifera, crinoids, echinoids, and corals. Since the Paleocene, in all the Western Outer Carpathian sedimentary areas, Lithothamnion-bryozoan facies developed and adapted to unstable conditions. Algae-bryozoan covers originating on the siliciclastic substrate are typical of these facies. This type of deposition was preserved practically until the final stage in the evolution of the Outer Carpathian basins.Web of Science117art. no. 74