Distributed Approximation of Maximum Independent Set and Maximum Matching

We present a simple distributed $\Delta$-approximation algorithm for maximum weight independent set (MaxIS) in the $\mathsf{CONGEST}$ model which completes in $O(\texttt{MIS}(G)\cdot \log W)$ rounds, where $\Delta$ is the maximum degree, $\texttt{MIS}(G)$ is the number of rounds needed to compute a maximal independent set (MIS) on $G$, and $W$ is the maximum weight of a node. %Whether our algorithm is randomized or deterministic depends on the \texttt{MIS} algorithm used as a black-box. Plugging in the best known algorithm for MIS gives a randomized solution in $O(\log n \log W)$ rounds, where $n$ is the number of nodes. We also present a deterministic $O(\Delta +\log^* n)$-round algorithm based on coloring. We then show how to use our MaxIS approximation algorithms to compute a $2$-approximation for maximum weight matching without incurring any additional round penalty in the $\mathsf{CONGEST}$ model. We use a known reduction for simulating algorithms on the line graph while incurring congestion, but we show our algorithm is part of a broad family of \emph{local aggregation algorithms} for which we describe a mechanism that allows the simulation to run in the $\mathsf{CONGEST}$ model without an additional overhead. Next, we show that for maximum weight matching, relaxing the approximation factor to ($2+\varepsilon$) allows us to devise a distributed algorithm requiring $O(\frac{\log \Delta}{\log\log\Delta})$ rounds for any constant $\varepsilon>0$. For the unweighted case, we can even obtain a $(1+\varepsilon)$-approximation in this number of rounds. These algorithms are the first to achieve the provably optimal round complexity with respect to dependency on $\Delta$

Exact Bayesian Inference on Discrete Models via Probability Generating Functions: A Probabilistic Programming Approach

We present an exact Bayesian inference method for discrete statistical models, which can find exact solutions to many discrete inference problems, even with infinite support and continuous priors. To express such models, we introduce a probabilistic programming language that supports discrete and continuous sampling, discrete observations, affine functions, (stochastic) branching, and conditioning on events. Our key tool is probability generating functions: they provide a compact closed-form representation of distributions that are definable by programs, thus enabling the exact computation of posterior probabilities, expectation, variance, and higher moments. Our inference method is provably correct, fully automated and uses automatic differentiation (specifically, Taylor polynomials), but does not require computer algebra. Our experiments show that its performance on a range of real-world examples is competitive with approximate Monte Carlo methods, while avoiding approximation errors

Exact Bayesian inference on discrete models via probability generating functions: a probabilistic programming approach

We present an exact Bayesian inference method for discrete statistical models, which can find exact solutions to a large class of discrete inference problems, even with infinite support and continuous priors. To express such models, we introduce a probabilistic programming language that supports discrete and continuous sampling, discrete observations, affine functions, (stochastic) branching, and conditioning on discrete events. Our key tool is probability generating functions: they provide a compact closed-form representation of distributions that are definable by programs, thus enabling the exact computation of posterior probabilities, expectation, variance, and higher moments. Our inference method is provably correct and fully automated in a tool called Genfer, which uses automatic differentiation (specifically, Taylor polynomials), but does not require computer algebra. Our experiments show that Genfer is often faster than the existing exact inference tools PSI, Dice, and Prodigy. On a range of real-world inference problems that none of these exact tools can solve, Genfer's performance is competitive with approximate Monte Carlo methods, while avoiding approximation errors

Monte Carlo simulations of the inside-intron recombination

Biological genomes are divided into coding and non-coding regions. Introns are non-coding parts within genes, while the remaining non-coding parts are intergenic sequences. To study the evolutionary significance of recombination inside introns we have used two models based on the Monte Carlo method. In our computer simulations we have implemented the internal structure of genes by declaring the probability of recombination between exons. One situation when inside-intron recombination is advantageous is recovering functional genes by combining proper exons dispersed in the genetic pool of the population after a long period without selection for the function of the gene. Populations have to pass through the bottleneck, then. These events are rather rare and we have expected that there should be other phenomena giving profits from the inside-intron recombination. In fact we have found that inside-intron recombination is advantageous only in the case when after recombination, besides the recombinant forms, parental haplotypes are available and selection is set already on gametes.Comment: 12 pages inc. 5 Figs., for Int. J. Mod. Phys. C 17, issue 4 (2006

Mechanical characterisation and crashworthiness performance of additively manufactured polymer-based honeycomb structures under in-plane quasi-static loading

ABSTRACTAdditive manufacturing technology is suitable for producing energy-absorbing devices with tunable mechanical properties and improved crashworthiness performance. In this study, the mechanical properties and macrostructural crushing behaviour of five additively manufactured polymer-based honeycomb structures (HS) are investigated. Subjected to in-plane loading, the experimental results of the HS are compared with numerical findings and theoretical predictions. Results indicate that deformation modes and overall crushing performance are influenced by utilising different parent materials. The polymer HS made from polyethylene terephthalate glycol gives the best overall crushing performance over the other polymers and polymer-fibre reinforcement HS. However, the crush force efficiency of HS made from polylactic acid is the least promising. The polymer-fibre reinforced HS outperforms some of the pure polymer-based ones in terms of specific energy absorption and shows a characteristic lightweight advantage. Hence, spotting it as a promising energy absorber utilised for crashworthiness application especially where ultra-lightweight property is highly desired

Elective cesarean section on psychiatric indications - tokophobia

Aim of the study: The aim of the study was to analyze the influence of tokophobia on delivery solution by Caesarean section. The number of deliveries solved by Caesarean section has increased significantly in recent years. In Poland, it has almost doubled since 2000 (from 18.1% to 37%) Research methods: A survey was used in the study. 25 first-born girls and 25 multi-rivers took part, the selection criterion was delivered by caesarean section. Results: The fear of giving birth was the cause of caesarean section in 12 of the 25 primigravidas and 12 of the 25 multigravidas. Conclusion: Fear of childbirth may be a very important issue related to planning the delivery method

Relaxation oscillations and ultrafast emission pulses in a disordered expanding polariton condensate

Semiconductor microcavities are often influenced by structural imperfections, which can disturb the flow and dynamics of exciton-polariton condensates. Additionally, in exciton-polariton condensates there is a variety of dynamical scenarios and instabilities, owing to the properties of the incoherent excitonic reservoir. We investigate the dynamics of an exciton-polariton condensate which emerges in semiconductor microcavity subject to disorder, which determines its spatial and temporal behaviour. Our experimental data revealed complex burst-like time evolution under non-resonant optical pulsed excitation. The temporal patterns of the condensate emission result from the intrinsic disorder and are driven by properties of the excitonic reservoir, which decay in time much slower with respect to the polariton condensate lifetime. This feature entails a relaxation oscillation in polariton condensate formation, resulting in ultrafast emission pulses of coherent polariton field. The experimental data can be well reproduced by numerical simulations, where the condensate is coupled to the excitonic reservoir described by a set of rate equations. Theory suggests the existence of slow reservoir temporarily emptied by stimulated scattering to the condensate, generating ultrashort pulses of the condensate emission.Publisher PDFPeer reviewe

Relaxation oscillations and ultrafast emission pulses in a disordered expanding polariton condensate

Semiconductor microcavities are often influenced by structural imperfections, which can disturb the flow and dynamics of exciton-polariton condensates. Additionally, in exciton-polariton condensates there is a variety of dynamical scenarios and instabilities, owing to the properties of the incoherent excitonic reservoir. We investigate the dynamics of an exciton-polariton condensate which emerges in semiconductor microcavity subject to disorder, which determines its spatial and temporal behaviour. Our experimental data revealed complex burst-like time evolution under non-resonant optical pulsed excitation. The temporal patterns of the condensate emission result from the intrinsic disorder and are driven by properties of the excitonic reservoir, which decay in time much slower with respect to the polariton condensate lifetime. This feature entails a relaxation oscillation in polariton condensate formation, resulting in ultrafast emission pulses of coherent polariton field. The experimental data can be well reproduced by numerical simulations, where the condensate is coupled to the excitonic reservoir described by a set of rate equations. Theory suggests the existence of slow reservoir temporarily emptied by stimulated scattering to the condensate, generating ultrashort pulses of the condensate emission.Publisher PDFPeer reviewe

Physical activity of pregnant women

Korabiusz Katarzyna, Wawryków Agata, Fabian-Danielewska Anna, Stecko Monika, Żukowska Magdalena, Janik Inga, Andrusewicz Wojciech, Torbé Andrzej. Physical activity of pregnant women. Journal of Education, Health and Sport. 2018;8(8):1026-1031. eISNN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.1414249 http://ojs.ukw.edu.pl/index.php/johs/article/view/5965 https://pbn.nauka.gov.pl/sedno-webapp/works/876966 The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part b item 1223 (26/01/2017). 1223 Journal of Education, Health and Sport eissn 2391-8306 7 © The Authors 2018; This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author (s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non commercial license Share alike. (http://creativecommons.org/licenses/by-nc-sa/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 02.08.2018. Revised: 18.08.2018. Accepted: 31.08.2018. Physical activity of pregnant women mgr Katarzyna Korabiusz¹, mgr Agata Wawryków¹, lek. Anna Fabian- Danielewska2, mgr Monika Stecko¹, lek. Magdalena Żukowska2, mgr Inga Janik¹, lek. Wojciech Andrusewicz2, prof. dr hab. n. med. Andrzej Torbé3 ¹ Pomorski Uniwersytet Medyczny w Szczecinie, Studium Doktoranckie Wydziału Nauk o Zdrowiu, ul. Żołnierska 54, 71-210 Szczecin 2 Pomorski Uniwersytet Medyczny w Szczecinie, Studium Doktoranckie Wydziału Lekarskiego, ul. Żołnierska 54, 71-210 Szczecin 3 Pomorski Uniwersytet Medyczny w Szczecinie, Klinika Położnictwa i Ginekologii, ul. Powstańców Wlkp. 72, 70-111 Szczecin Dane autora korespondencyjnego: Katarzyna Korabiusz [email protected] Key words: physical activity, pregnancy. ABSTRACT Every pregnant woman should be aware that her every day health habits affect the child's health, but also her health during pregnancy, delivery and post-partum period. Physical activity plays an important role during pregnancy. It improves the overall physical condition and prevents many ailments of pregnancy. The most important aspect of taking physical activity during pregnancy is the right choice of exercise and regularity and appropriate technique. Due to many benefits of proper exercises during pregnancy, pregnant women should be encouraged and educated in this area