On Pairs of Difference Operators Satisfying: [P,Q] = Id

Different finite difference replacements for the derivative are analyzed in the context of the Heisenberg commutation relation. The type of the finite difference operator is shown to be tied to whether one can naturally consider $P$ and $X$ to be self-adjoint and skew self-adjoint or whether they have to be viewed as creation and annihilation operators. The first class, generalizing the central difference scheme, is shown to give unitary equivalent representations. For the second case we construct a large class of examples, generalizing previously known difference operator realizations of $[P,X]=Id$.Comment: 32 pages, plain Te

Algebraic construction of a coboundary of a given cycle

We present an algebraic construction of the coboundary of a given cycle as a simpler alternative to the geometric one introduced in [M. Allili, T. Kaczyński, Geometric construction of a coboundary of a cycle, Discrete Comput. Geom. 25 (2001), 125–140, T. Kaczyński, Recursive coboundary formula for cycles in acyclic chain complexes, Topol. Methods Nonlinear Anal. 18 (2001), 351–371]

Tensor network simulation of the quantum Kibble-Zurek quench from the Mott to superfluid phase in the two-dimensional Bose-Hubbard model

Quantum simulations of the Bose-Hubbard model (BHM) at commensurate filling can follow spreading of correlations after a sudden quench for times long enough to estimate their propagation velocities. In this work we perform tensor network simulation of the quantum Kibble-Zurek (KZ) ramp from the Mott towards the superfluid phase in the square lattice BHM and demonstrate that even relatively short ramp/quench times allow one to test the power laws predicted by the KZ mechanism (KZM). They can be verified for the correlation length and the excitation energy but the most reliable test is based on the KZM scaling hypothesis for the single particle correlation function: the correlation functions for different quench times evaluated at the same scaled time collapse to the same scaling function of the scaled distance. The scaling of the space and time variables is done according to the KZ power laws.Comment: 8 pages; minor corrections, to appear in PRB

The quality of data and the accuracy of energy generation forecast by artificial neural networks

The paper presents the issues related to predicting the amount of energy generation, in a particular wind power plant comprising five generators located in south-eastern Poland. The location of wind power plant, the distribution and type of applied generators, and topographical conditions were given and the correlation between selected weather parameters and the volume of energy generation was discussed. The primary objective of the paper was to select learning data and perform forecasts using artificial neural networks. For comparison, conservative forecasts were also presented. Forecasts results obtained shaw that Artificial Neural Networks are more universal than conservative method. However their forecast accuracy of forecasts strongly depends on the selection of explanatory dat

Sliced generative models

In this paper we discuss a class of AutoEncoder based generative models based on one dimensional sliced approach. The idea is based on the reduction of the discrimination between samples to one-dimensional case. Our experiments show that methods can be divided into two groups. First consists of methods which are a modification of standard normality tests, while the second is based on classical distances between samples. It turns out that both groups are correct generative models, but the second one gives a slightly faster decrease rate of Frechet Inception Distance (FID)

Effect of Pasteurization on Rheological Properties of White Carrot Juice

AbstractThe rheological behaviour of untreated and pasteurized white carrot juice was modelled to investigate the influence of temperature on viscosity and its fluid type. The research was conducted using a rotational viscometer at shear rates ranging from 1 to 100 s-1 and temperatures between 10 and 60°C. The rheological behaviour of untreated white carrot juice was well described by the Newtonian model while the pasteurized juice showed a pseudoplastic behaviour and was satisfactorily fitted to Ostwald-de Waele model. The Arrhenius equation adequately described the effect of temperature on the viscosity. The activation energies were depended on kind of fluid and were 15.41 and 5.90kJ/mol for untreated and pasteurized white carrot juice, respectively

The impact of size and shape of particles of undergrowth and herbs mixtures on aerodynamic properties

The impact of the size and shape of a selected group of herbs (dried juniper berries – Juniperus communis, dry blueberries – Vaccinium myrtillus, petals of cornflower – Centaurea cyanus) on the value of the volatility coefficient, the coefficient of sphericity and the critical speed was analysed in the presented research. A laboratory anemometer to measure the speed of air was used. The determination of the volatility coefficient of particular size fractions was conducted on the basis of critical speed values, calculated as an average established after five measurements. The established aerodynamic properties of particular mixtures allow the determination and the assessment of differences among fractions of valuable resources and different impurities. The presented data might constitute a basis to determine the scope of differences among them and establish interrelations which allow the application of proper parameters for the pneumatic separation process in practice

Response of endolithic chroococcidiopsis strains from the polyextreme Atacama desert to light radiation

Cyanobacteria exposed to high solar radiation make use of a series of defense mechanisms, including avoidance, antioxidant systems, and the production of photoprotective compounds such as scytonemin. Two cyanobacterial strains of the genus Chroococcidiopsis from the Atacama Desert – which has one of the highest solar radiation levels on Earth- were examined to determine their capacity to protect themselves from direct photosynthetically active (PAR) and ultraviolet radiation (UVR): the UAM813 strain, originally isolated from a cryptoendolithic microhabitat within halite (NaCl), and UAM816 strain originally isolated from a chasmoendolithic microhabitat within calcite (CaCO3). The oxidative stress induced by exposure to PAR or UVR C PAR was determined to observe their short-term response, as were the long-term scytonemin production, changes in metabolic activity and ultrastructural damage induced. Both strains showed oxidative stress to both types of light radiation. The UAM813 strain showed a lower acclimation capacity than the UAM816 strain, showing an ever-increasing accumulation of reactive oxygen species (ROS) and a smaller accumulation of scytonemin. This would appear to reflect differences in the adaptation strategies followed to meet the demands of their different microhabitats.This study was supported by grant PGC2018-094076-B-I00 from MCIU/AEI (Spain) and FEDER (UE). MC was supported by grant BES 2014-069106 from the Spanish Ministry of Science and Innovation (MCINN).Peer reviewe

Ocena czystości mikrobiologicznej wybranych komponentów pasz i mieszanek poddanych obróbce termicznej

Microorganisms which contaminate animal feeds pose a threat not only to animals but also indirectly to humans through their consumption of products of animal origin. The aim of the present study was to assess microbiological cleanness of selected resources and ready-made feed mixtures before and after thermal processing. The results indicated that the most bacteriologically contaminated resources were oats (Avena sativa), wheat middlings, wheat (Triticum vulgare), and poultry feed mixture KDKA F35%. The least contaminated were maize (Zea) and Prowit – feed mixture for livestock. The examined feed resources were contaminated with moulds, among which dominated: Aspergillus and Penicillium. The findings of bacteriological and mycological contamination assure instead of allow stating that thermal processing limits microbiological contamination of animal feeds. In order to protect the health of animals as well as consumers it seems advisable to seek new methods of thermal processing in the production of animal feeds to provide their high quality and safety.Mikroorganizmy zanieczyszczające pasze stanowią zagrożenia zarówno dla zwierząt, ale także pośrednio dla ludzi poprzez spożywanie produktów pochodzenia zwierzęcego. Celem niniejszej pracy była ocena czystości mikrobiologicznej wybranych surowców oraz gotowych mieszanek paszowych przed oraz po obróbce termicznej. Z przeprowadzonych badań wynika, że najbardziej zanieczyszczonymi bakteriologicznie surowcami był owies, śruta pszenna, pszenica oraz mieszanka paszowa dla drobiu KDKA F35%. Najmniej zanieczyszczeń posiadała kukurydza oraz mieszanka dla trzody Prowit. Badane surowce paszowe zanieczyszczone pleśniami, wśród których dominowały rodzaje: Aspergillus i Penicillium. Uzyskane wyniki badań zanieczyszczenia bakteriologicznego i mykologicznego pozwalają stwierdzić iż proces obróbki termicznej ogranicza zanieczyszczenie mikrobiologiczne pasz. W celu ochrony zdrowia zwierząt oraz konsumentów wydaje się być wskazane poszukiwanie nowych metod obróbki termicznej w produkcji pasz, aby zapewniać im wysoką jakość i bezpieczeństwo