Deep learning for diffusion in porous media

We adopt convolutional neural networks (CNN) to predict the basic properties of the porous media. Two different media types are considered: one mimics the sandstone, and the other mimics the systems derived from the extracellular space of biological tissues. The Lattice Boltzmann Method is used to obtain the labeled data necessary for performing supervised learning. We distinguish two tasks. In the first, networks based on the analysis of the system's geometry predict porosity and effective diffusion coefficient. In the second, networks reconstruct the system's geometry and concentration map. In the first task, we propose two types of CNN models: the C-Net and the encoder part of the U-Net. Both networks are modified by adding a self-normalization module. The models predict with reasonable accuracy but only within the data type, they are trained on. For instance, the model trained on sandstone-like samples overshoots or undershoots for biological-like samples. In the second task, we propose the usage of the U-Net architecture. It accurately reconstructs the concentration fields. Moreover, the network trained on one data type works well for the other. For instance, the model trained on sandstone-like samples works perfectly on biological-like samples.Comment: 17 pages, 19 figure

Growth and electronic and magnetic structure of iron oxide films on Pt(111)

Ultrathin (111)-oriented polar iron oxide films were grown on a Pt(111) single crystal either by the reactive deposition of iron or oxidation of metallic iron monolayers. These films were characterized using low energy electron diffraction, scanning tunneling microscopy and conversion electron Mossbauer spectroscopy. The reactive deposition of Fe led to the island growth of Fe3O4, in which the electronic and magnetic properties of the bulk material were modulated by superparamagnetic size effects for thicknesses below 2 nm, revealing specific surface and interface features. In contrast, the oxide films with FeO stoichiometry, which could be stabilized as thick as 4 nm under special preparation conditions, had electronic and magnetic properties that were very different from their bulk counterpart, w\"ustite. Unusual long range magnetic order appeared at room temperature for thicknesses between three and ten monolayers, the appearance of which requires severe structural modification from the rock-salt structure.Comment: 17 pages, 6 figures, 50 reference

Weight status, BMI and physical fitness in polish youth: relationships between 1986 and 2016

One of the components affecting the level of health is physical fitness and diets, which is also considered the foundation of a healthy lifestyle. Methods: Samples by survey ranged from 871 to 1,417 (boys) and from 843 to 1,326 (girls). Speed (5 m run), agility (figure-8-run), explosive power (vertical jump), flexibility (stand and reach) and cardiovascular fitness (step test) were measured. The Body Mass Index (BMI) of each student was classified as Thin, Normal weight or Overweight/Obese (Owt/Ob) relative to International Obesity Task Force (IOTF) criteria. Fitness items were compared among weight status groups and across surveys with sex-specific analyses of covariance. Regressions of each fitness item on the BMI in the four surveys were done using linear and nonlinear quadratic models. Results: Performances on all fitness tests except flexibility were poorer among Owt/Ob compared to Normal and Thin youth, but performances on fitness tests within weight status groups did not differ consistently across surveys. Conclusions: Relationships between the BMI and fitness tests varied across surveys, but suggested reasonably consistent curvilinear relationships between fitness tests and the BMI among boys more so than girls.info:eu-repo/semantics/publishedVersio

Main Field Tracking Measurement in the LHC Superconducting Dipole and Quadrupole Magnets

One of the most stringent requirements during the energy ramp of the Large Hadron Collider (LHC) is to have a constant ratio between dipole-quadrupole and dipole-dipole field so as to control the variation of the betatron tune and of the beam orbit throughout the acceleration phase, hence avoiding particle loss. To achieve the nominal performance of the LHC, a maximum variation of ±0.003 tune units can be tolerated. For the commissioning with low intensity beams, acceptable bounds are up to 30 times higher. For the quadrupole-dipole integrated field ratio, the above requirements translate in the tight windows of 6 ppm and 180 ppm, while for dipole differences between sectors the acceptable error is of the order of 10^-4. Measurement and control at this level are challenging. For this reason we have launched a dedicated measurement R&D to demonstrate that these ratios can be measured and controlled within the limits for machine operation. In this paper we present the techniques developed to power the magnets during the current ramps, the instrumentation and data acquisition setup used to perform the tracking experiments, the calibration procedure and the data reduction employed

A Demonstration Experiment for the Main Field Tracking and the Sextupole and Decapole Compensation in the LHC Main Magnets

A dedicated measurement campaign was set up to test the FiDeL concept and its LSA implementation. The test was performed by demonstrating the tracking of B1 and B2 for two LHC main dipoles and one LHC main quadrupole. It also included the compensation of the b3 and b5 harmonics in the dipole magnets using the sextupole and decapole corrector magnets. In this report we present the techniques developed to power the magnets for these tests during the current ramps; the instrumentation and data acquisition setup used to perform the tracking experiments; the calibration procedure and data corrections employed; and finally the main results obtained

A Demonstration Experiment for the Forecast of Magnetic Field and Field Errors in the Large Hadron Collider

In order to reduce the burden on the beam-based feedback, the Large Hadron Collider control system is equipped with the Field Description for the LHC (FiDeL) which provides a forecast of the magnetic field and the multipole field errors. FiDeL has recently been extensively tested at CERN to determine main field tracking, multipole forecasting and compensation accuracy. This paper describes the rationale behind the tests, the procedures employed to power the main magnets and their correctors, and finally, we present the results obtained. We also give an indication of the prediction accuracy that the system can deliver during the operation of the LHC and we discuss the implications that these will have on the machine performance

Synthetic light-activated ion channels for optogenetic activation and inhibition

Optogenetic manipulation of cells or living organisms became widely used in neuroscience following the introduction of the light-gated ion channel channelrhodopsin-2 (ChR2). ChR2 is a non-selective cation channel, ideally suited to depolarize and evoke action potentials in neurons. However, its calcium (Ca2$^{2+}$) permeability and single channel conductance are low and for some applications longer-lasting increases in intracellular Ca$^{2+}$ might be desirable. Moreover, there is need for an efficient light-gated potassium (K$^{+}$) channel that can rapidly inhibit spiking in targeted neurons. Considering the importance of Ca$^{2+}$ and K$^{+}$ in cell physiology, light-activated Ca$^{2+}$-permeant and K$^{+}$-specific channels would be welcome additions to the optogenetic toolbox. Here we describe the engineering of novel light-gated Ca$^{2+}$-permeant and K$^{+}$-specific channels by fusing a bacterial photoactivated adenylyl cyclase to cyclic nucleotide-gated channels with high permeability for Ca$^{2+}$ or for K$^{+}$, respectively. Optimized fusion constructs showed strong light-gated conductance in Xenopus laevis oocytes and in rat hippocampal neurons. These constructs could also be used to control the motility of Drosophila melanogaster larvae, when expressed in motoneurons. Illumination led to body contraction when motoneurons expressed the light-sensitive Ca$^{2+}$-permeant channel, and to body extension when expressing the light-sensitive K$^{+}$ channel, both effectively and reversibly paralyzing the larvae. Further optimization of these constructs will be required for application in adult flies since both constructs led to eclosion failure when expressed in motoneurons

The magnetic model of the LHC in the early phase of beam commissioning

The relation between field and current in each family of the Large Hadron Collider magnets is modelled with a set of empirical equations (FiDeL) whose free parameters are fit on magnetic measurements. They take into account residual magnetization, persistent currents, hysteresis, saturation, decay and snapback during initial part of the ramp. Here we give a first summary of the reconstruction of the magnetic field properties based on the beam observables (orbit, tune, coupling, chromaticity) and a comparison with the expectations. The most critical issues for the machine performance in terms of knowledge of the relation magnetic field vs current are pointed out.peer-reviewe