Chempy\mathit{Chempy}: A flexible chemical evolution model for abundance fitting - Do the Sun's abundances alone constrain chemical evolution models?

Elemental abundances of stars are the result of the complex enrichment history of their galaxy. Interpretation of observed abundances requires flexible modeling tools to explore and quantify the information about Galactic chemical evolution (GCE) stored in such data. Here we present Chempy, a newly developed code for GCE modeling, representing a parametrized open one-zone model within a Bayesian framework. A Chempy model is specified by a set of 5-10 parameters that describe the effective galaxy evolution along with the stellar and star-formation physics: e.g. the star-formation history, the feedback efficiency, the stellar initial mass function (IMF) and the incidence of supernova type Ia (SN Ia). Unlike established approaches, Chempy can sample the posterior probability distribution in the full model parameter space and test data-model matches for different nucleosynthetic yield sets. We extend Chempy to a multi-zone scheme. As an illustrative application, we show that interesting parameter constraints result from only the ages and elemental abundances of Sun, Arcturus and the present-day interstellar medium (ISM). For the first time, we use such information to infer IMF parameter via GCE modeling, where we properly marginalize over nuisance parameters and account for different yield sets. We find that of the IMF $11.6_{-1.6}^{+2.1}$ % explodes as core-collapse SN, compatible with Salpeter 1955. We also constrain the incidence of SN Ia per 10^3 Msun to 0.5-1.4. At the same time, this Chempy application shows persistent discrepancies between predicted and observed abundances for some elements, irrespective of the chosen yield set. These cannot be remedied by any variations of Chempy's parameters and could be an indication for missing nucleosynthetic channels. Chempy should be a powerful tool to confront predictions from stellar nucleosynthesis with far more complex abundance data sets.Comment: 19 pages, 17 figures, accepted for publication in A&A, python code: https://github.com/jan-rybizki/Chemp

The Origin of the Czech and Slovak Pluralist Party Systems

The article analyzes the process of pluralistic party system renewal in Czechoslovakia after the fall of communism in 1989. It shows the initial conditions and major actors, as well as factors that infl uenced party system structure and behaviour in the environment of a post-communist society without a recent democratic tradition. Special attention is devoted to the differences between Czech and Slovak party systems, as both parts of the former united Czechoslovakia demonstrated differences in their respective party systems both before and after 1989. After the introduction of key political parties, the results of 1990 general parliamentary election and its impact on the party system are analyzed

Small photovoltaic system

Bakalářská práce popisuje dnešní podobu fotovoltaiky. V úvodní časti je popsán samotný zdroj solární energie, základní princip její přeměny na elektrickou a jeho historie. V navazujících oddílech práce shrnuje druhy fotovoltaických článků, jejich členění z hlediska ekonomického, druhu použitého materiálu a stručný popis získaných vlastností. Vlastní práce dále obsahuje konstrukci fotovoltaických panelů a následné uspořádání do celků (systémů) s připojením k distribuční elektrické síti nebo bez něj, shrnuje dostupné technologie vhodné pro zvyšování účinnosti a současné legislativní podmínky pro provoz fotovoltaických elektráren v České republice. Nosná část celé práce je založena na návrhu fotovoltaického systému grid-on pro reálný objekt - rodinný dům. Zahrnuje komplexní studii zabývající se polohou daného objektu, volbou vhodných komponent a výpočtem jejich celkové produkované elektrické energie včetně teoretické kalkulace návratnosti investic. V závěrečné části jsou prezentovány dosažené cíle, výhody a nevýhody investice a samotná realizovatelnost projektu v praxi.This thesis describes the fotovoltaics at the present time. Introduction includes information regarding to resources of solar energy, main principle of transformation solar energy to electrical and history. Next parts summarise types of solar cells in economical term, types of material and description of their properties. Thesis includes the construction of fotovoltaic panel and its configuration to fotovoltaic systems with or without connection to electrical power network, contains convenient technologies for improving efficiency and the czech legislation. Final part focuses on designing grid-on system for real object including komplex study of object location, used components and calculation of whole produced electric energy and pay-back time. The main aims are presented in conclusion as well as advantages and disadvantages of the investment.

MEANING AND USAGE OF A CONCEPTUAL ENTERPRISE RISK MANAGEMENT FRAMEWORK – A CASE STUDY

Enterprise Risk Management (ERM) includes processes and methodologies for organizations to manage companies’ risks. Due to an increase in the environmental complexity, a standardized approach of managing risks and opportunities is not only useful, but absolutely essential for business continuation – the way organizations deal with such risks is the key role for success and can be seen in the company’s overall performance. In a previous paper the authors suggested a model for ERM assessment. In order to proof this model, this paper presents a case study of a production company with a working ERM to evaluate the model, based on a real example. The results demonstrate that a suggested model to assess ERM and its performance is practically useable by organizations and might be further extended in future studies

MicroRNA-22 increases senescence and activates cardiac fibroblasts in the aging heart

MicroRNAs (miRs) are small non- coding RNA molecules controlling a plethora of biological processes such as development, cellular survival and senescence. We here determined miRs differentially regulated during cardiac postnatal development and aging. Cardiac function, morphology and miR expression profiles were determined in neonatal, 4 weeks, 6 months and 19 months old normotensive male healthy C57/Bl6N mice. MiR-22 was most prominently upregulated during cardiac aging. Cardiac expression of its bioinformatically predicted target mimecan (osteoglycin, OGN) was gradually decreased with advanced age. Luciferase reporter assays validated mimecan as a bona fide miR-22 target. Both, miR-22 and its target mimecan were co- expressed in cardiac fibroblasts and smooth muscle cells. Functionally, miR-22 overexpression induced cellular senescence and promoted migratory activity of cardiac fibroblasts. Small interference RNA-mediated silencing of mimecan in cardiac fibroblasts mimicked the miR-22-mediated effects. Rescue experiments revealed that the effects of miR-22 on cardiac fibroblasts were only partially mediated by mimecan. In conclusion, miR-22 upregulation in the aging heart contributed at least partly to accelerated cardiac fibroblast senescence and increased migratory activity. Our results suggest an involvement of miR-22 in age-associated cardiac changes, such as cardiac fibrosis