Number of found documents: 8766
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Excessive extrapolations of Einstein's equations
Křížek, Michal; Somer, L.
2020 - English
The standard cosmological model is surprisingly quite thoroughly investigated even though it possesses many paradoxes. We present several arguments indicating why excessive extrapolations of Einstein's equations to cosmological distances are questionable. First, we show how to express explicitly the first of Einstein's 10 partial differential equations to demonstrate their extremely large complexity. Therefore, it would be very difficult to find their solution for two or more bodies to model, e.g., the evolution of the Solar system. Further, we present some unexpected failures of the Schwarzschild and Friedmann solution of these equations. Then we explain why application of Einstein's equations to the whole universe represents incorrect extrapolations that lead to dark matter, dark energy, and several unrealistic situations. Finally, we give 10 further arguments showing why celebrated Einstein's equations do not describe reality well. Keywords: Einstein's equations; Schwarzschild solution; Friedmann equation Available in digital repository of the ASCR
Excessive extrapolations of Einstein's equations

The standard cosmological model is surprisingly quite thoroughly investigated even though it possesses many paradoxes. We present several arguments indicating why excessive extrapolations of ...

Křížek, Michal; Somer, L.
Matematický ústav, 2020

Institutions, Financial Development, and Small Business Survival: Evidence from European Emerging Economies
Iwasaki, I.; Kočenda, Evžen; Shida, Y.
2020 - English
In this paper, we traced the survival status of 94,401 small businesses in 17 European emerging markets from 2007–2017 and empirically examined the determinants of their survival, focusing on institutional quality and financial development. We found that institutional quality and level of financial development exhibit statistically significant and economically meaningful impacts on the survival probability of the SMEs being researched. The evidence holds even when we control for a set of firm-level characteristics such as ownership structure, financial performance, firm size, and age. The findings are also uniform across industries and country groups and robust beyond the difference in assumption of hazard distribution. Keywords: small business; survival analysis; European emerging markets Fulltext is available at external website.
Institutions, Financial Development, and Small Business Survival: Evidence from European Emerging Economies

In this paper, we traced the survival status of 94,401 small businesses in 17 European emerging markets from 2007–2017 and empirically examined the determinants of their survival, focusing on ...

Iwasaki, I.; Kočenda, Evžen; Shida, Y.
Ústav teorie informace a automatizace, 2020

Financial Crime and Punishment: A Meta-Analysis
de Batz, L.; Kočenda, Evžen
2020 - English
We examine how the publication of intentional financial crimes committed by listed firms is interpreted by financial markets, using a systematic and quantitative review of existing empirical studies. Specifically, we conduct a meta-regression analysis and investigate the extent and nature of the impact that the publication of financial misconducts exerts on stock returns. We survey 111 studies, published between 1978 and 2020, with a total of 439 estimates from event studies. Our key finding is that the average abnormal returns calculated from this empirical literature are affected by a negative publication selection bias. Still, after controlling for this bias, our meta-analysis indicates that publications of financial crimes are followed by statistically significant negative abnormal returns, which suggests the existence of an informational effect. Finally, the MRA results demonstrate that crimes committed in common law countries, alleged crimes, and accounting crimes carry particularly weighty information for market participants. The results call for more transparency on side of enforcers along enforcement procedures, to foster timely and proportionate market reactions and support efficient markets. Keywords: Meta-Analysis; Event study; Financial Misconduct; Fraud; Financial Markets; Returns; Listed Companies; Information and Market Efficiency Fulltext is available at external website.
Financial Crime and Punishment: A Meta-Analysis

We examine how the publication of intentional financial crimes committed by listed firms is interpreted by financial markets, using a systematic and quantitative review of existing empirical studies. ...

de Batz, L.; Kočenda, Evžen
Ústav teorie informace a automatizace, 2020

Selective Attention in Exchange Rate Forecasting
Kapounek, S.; Kučerová, Z.; Kočenda, Evžen
2020 - English
We analyze the exchange rate forecasting performance under the assumption of selective attention. Although currency markets react to a variety of different information, we hypothesize that market participants process only a limited amount of information. Our analysis includes more than 100,000 news articles relevant to the six most-traded foreign exchange currency pairs for the period of 1979–2016. We employ a dynamic model averaging approach to reduce model selection uncertainty and to identify time-varying probability to include regressors in our models. Our results show that smaller sizes models accounting for the presence of selective attention offer improved fitting and forecasting results. Specifically, we document a growing impact of foreign trade and monetary policy news on the euro/dollar exchange rate following the global financial crisis. Overall, our results point to the existence of selective attention in the case of most currency pairs. Keywords: exchange rate; selective attention; news; forecasting; dynamic model averaging Fulltext is available at external website.
Selective Attention in Exchange Rate Forecasting

We analyze the exchange rate forecasting performance under the assumption of selective attention. Although currency markets react to a variety of different information, we hypothesize that market ...

Kapounek, S.; Kučerová, Z.; Kočenda, Evžen
Ústav teorie informace a automatizace, 2020

On the 3D Dynamics of the Wake Behind a Circular Cylinder
Uruba, Václav; Procházka, Pavel P.; Skála, Vladislav
2020 - English
Flow in the wake of a circular cylinder is studied experimentally using time-resolved stereo PIV method. Special attention is paid to 3D topology of dynamical structures. While the distribution of statistic quantities along the cylinder is uniform, and i.e. 2D, the instantaneous flow structure is fully 3D. Within the velocity fluctuating flow field the structures containing streamwise vorticity and velocity components are dominant. The POD modes connected with von Kármán vortex street are identified. Keywords: circular cylinder; wake; 3D structure; POD Fulltext is available at external website.
On the 3D Dynamics of the Wake Behind a Circular Cylinder

Flow in the wake of a circular cylinder is studied experimentally using time-resolved stereo PIV method. Special attention is paid to 3D topology of dynamical structures. While the distribution of ...

Uruba, Václav; Procházka, Pavel P.; Skála, Vladislav
Ústav termomechaniky, 2020

Topical Problems of Fluid Mechanics 2020
Šimurda, David; Bodnár, T.
2020 - English
Proceedings consist of contributions dealing with both research on various problems in fluid mechanics and mathematical or experimental methods utilizable for solution of such problems. Keywords: experimental fluid mechanics; mathematical modelling; CFD; turbulence Available at various institutes of the ASCR
Topical Problems of Fluid Mechanics 2020

Proceedings consist of contributions dealing with both research on various problems in fluid mechanics and mathematical or experimental methods utilizable for solution of such problems.

Šimurda, David; Bodnár, T.
Ústav termomechaniky, 2020

Measurements on TR-W-1 Cascade
Luxa, Martin; Šimurda, David
2020 - English
The research report contains experimetal data from optical and pneumatic measurements on transonic profile cascade with linear part of suction side downstream the sonic line, which is intended for the rotor wheal of a last stage of steam turbine Keywords: transonic flow; steam turbine; profile cascade Available at various institutes of the ASCR
Measurements on TR-W-1 Cascade

The research report contains experimetal data from optical and pneumatic measurements on transonic profile cascade with linear part of suction side downstream the sonic line, which is intended for the ...

Luxa, Martin; Šimurda, David
Ústav termomechaniky, 2020

Measurements on TR-W-2 Cascade
Luxa, Martin; Šimurda, David
2020 - English
The research report contains experimetal data from optical and pneumatic measurements on transonic profile cascade with non-linear part of suction side downstream the sonic line, which is intended for the rotor wheal of a last stage of steam turbine. Keywords: transonic flow; steam turbine; profile cascade Available at various institutes of the ASCR
Measurements on TR-W-2 Cascade

The research report contains experimetal data from optical and pneumatic measurements on transonic profile cascade with non-linear part of suction side downstream the sonic line, which is intended for ...

Luxa, Martin; Šimurda, David
Ústav termomechaniky, 2020

An experimental investigation of yield surfaces anisotropies
Štefan, Jan; Parma, Slavomír; Marek, René; Plešek, Jiří; Feigenbaum, H. P.; Ciocanel, C.
2020 - English
This contribution is dedicated to a rigorous experimental procedure for evaluation of yield surfaces of common metallic materials. This yield surface tracing procedure employs thin-walled tubular specimens to identify individual yield points of the material under arbitrary combinations of axial load and torque. A yield point is identified on the basis of a prescribed threshold for the effective plastic strain that is being continuously and fully automatically evaluated throughout the test. The experimental results generated with this tracing method are promising, leading to shapes of the yield surfaces conform with the von Mises criterion. The proposed methodology can effectively capture the YS shape. Keywords: experimental mechanics; yield surface; directional distortional hardening; metallic materials Available at various institutes of the ASCR
An experimental investigation of yield surfaces anisotropies

This contribution is dedicated to a rigorous experimental procedure for evaluation of yield surfaces of common metallic materials. This yield surface tracing procedure employs thin-walled tubular ...

Štefan, Jan; Parma, Slavomír; Marek, René; Plešek, Jiří; Feigenbaum, H. P.; Ciocanel, C.
Ústav termomechaniky, 2020

Random response of a dynamic system under polynomial of a white noise
Náprstek, Jiří; Fischer, Cyril
2020 - English
Many types of external additive random excitation of dynamic systems admit to be modelled as a combination of powers of a Gaussian noise. Such a type of excitation produces a non-Gaussian response even if the dynamic system is linear and the excitation is additive only. Although the excitation as a whole is non-Gaussian, the problem can be transformed into the form of a linear system with an additive and multiplicative white noise excitation which _nally produces a non-Gaussian response. The general method of transformation, the respective FPK equation, basic stochastic moments of the response, and a demonstrative example are discussed. Keywords: non-Gaussian excitation; nonlinear filtering; Kronecker algebra Available at various institutes of the ASCR
Random response of a dynamic system under polynomial of a white noise

Many types of external additive random excitation of dynamic systems admit to be modelled as a combination of powers of a Gaussian noise. Such a type of excitation produces a non-Gaussian response ...

Náprstek, Jiří; Fischer, Cyril
Ústav teoretické a aplikované mechaniky, 2020

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