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Behavioural selection criteria for Czech police puppies to assess their chances of certification.
Hradecká, Lenka ; Bartoš, Luděk (advisor) ; Martin, Martin (referee)
The project based on behavioural tests of 7 week old German Shepherd puppies performed in police kennel in Prackovice nad Labem and Domažlice. The project focused on verification of the usability and improvement of the selection of puppies using behavioural test. We tested the possibility of environmental effect (presence of shooting range near the kennel Domažlice) on the later success of puppies in the behavioural test. The aim of the project was collecting additional data which were use to improve and verify procedure for early selection of puppies. We checked the possibility of habituation breeding females and their puppies to noise, including monitoring of the different environments in the kennels in. It was found that different results are affected by of their mothers. This means that puppies raised by mothers from the police kennel near shooting range are better evaluated later in the disciplines of evaluating response to noise compared with pups from mothers of police kennel without shooting range. Worse response to noise had pups from litters with a higher number of pups.
Reviews summarizing the literature on heritability of behavioural traits in dogs have been published repeatedly over the last four decades. The conclusions of these reviews vary to some extent. We applied meta-analysis and re-evaluated the literature available collecting 47 references dealing with heritability of behavioural traits in domestic dogs. For each study included, data was extracted for individual behavioural traits. Each of these traits was entered into the analysis as a separate unit of measure, giving a total of 1761 measures. We classified the traits measured in each study into five functional categories (Environment, Herding, Hunting, Play, and Psychical characteristic). The metaanalysis has shown low general heritability of the categorised behavioural traits analysed. Thus, the commonly used behaviour tests for many breeds, to determine the dog's eligibility for reproducing, traditionally required by many associations, is not supported by the present results of the meta-analysis.
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A use of epidemiology data for a cancer risk assessment and the recautionary principle
Bencko, Vladimír
The traditional approaches and study designs in cancer epidemiology have not been very successful in identifying and evaluating adequately the potential risk and/or protective factors associated with the disease. The main reasons for the failure are often due to small study sample size, and inadequate exposure information. In this paper, issues and approaches relevant to these two challenges are discussed. Multicentre study is proposed as a way to increase study size and to mitigate criticism about meta-analysis of independent studies. A multicentre study of large cohort or case–control studies also offers an exciting opportunity to study the contribution of epigenetic events that may be associated with life-style and environmental risk factors for human health. Optimizing methods for exposure assessment and how to reduce exposure misclassification represent a difficult component in epidemiology studies. A potentially useful approach for improving exposure estimate is to rely on biomarkers of exposures. An example is provided to demonstrate how biomarkers of exposures could provide valuable information in addition to exposure measurements in traditional epidemiological studies. Finally, it is argued that risk assessment and the precautionary principle should not be viewed as conflicting paradigms but, rather, as a complementary approach for developing appropriate policies to address risks posed by exposure to carcinogens and a wide spectrum of other health hazards.
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Prodejní cena a čas na trhu s nemovitostmi: Meta-analýza
Kuncová, Barbora ; Čadil, Jan (advisor) ; Slaný, Martin (referee)
The aim of the thesis is to broaden the research in the field of housing economics using the statistical tool of meta-analysis. The thesis examines the relationship between the selling price of a house and the time the house spends at the housing market. Although the research investigating this relation is of a wide comprehension, the results arising from various primary studies differ a lot. The goal of the thesis is to explain the source of this heterogeneity and determine the factors causing this variation. According to the results, it can be concluded that the effect size is influenced mainly by number of observations, modelling technique and specification of the model. Median income or location are other factors also determining the size of estimated coefficients. Also publication bias has been investigated although its presence is not confirmed in this thesis.
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Natural Resources and Economic Growth: A Meta-Analysis
Havránek, Tomáš ; Horváth, Roman ; Zeynalov, Ayaz
An important question in development studies is how natural resource richness affects long-term economic growth. No consensus answer, however, has yet emerged, with approximately 40% of empirical papers finding a negative effect, 40% finding no effect, and 20% finding a positive effect. Does the literature taken together imply the existence of the so-called natural resource curse? In a quantitative survey of 402 estimates reported in 33 studies, we find that the effect of natural resources on growth is very small when potential publication bias and method heterogeneity are taken into account. Our results also suggest that three aspects of study design are especially effective in explaining the differences in results across studies: 1) including an interaction between natural resources and institutional quality, 2) controlling for the level of investment activity, and 3) distinguishing between different types of natural resources.
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Habit Formation in Consumption: A Meta-Analysis
Havránek, Tomáš ; Rusnák, Marek ; Sokolova, Anna
We examine 567 estimates of habit formation from 69 studies published in peer-reviewed journals. In contrast to previous results for most fields of empirical economics, we find no publication bias in the literature. The median estimated strength of habit formation equals 0.4, but the estimates vary widely both within and across studies. We use Bayesian model averaging to assign a pattern to this variance while taking into account model uncertainty. Studies using micro data report consistently smaller estimates than macro studies: 0.1 vs. 0.6 on average. The difference remains large when we control for 21 other study aspects, such as data frequency, geographical coverage, variable definition, estimation approach, and publication characteristics. We also find that estimates of external habit formation tend to be substantially larger than those of internal habits, that evidence for habits weakens when researchers use higher data frequencies, and that estimates differ systematically across countries.
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Bank Competition and Financial Stability: Much Ado about Nothing?
Havránek, Tomáš ; Žigraiová, Diana
The theoretical literature gives conflicting predictions on how bank competition should affect financial stability, and dozens of researchers have attempted to evaluate the relationship empirically. We collect 598 estimates of the competition-stability nexus reported in 31 studies and analyze the literature using meta-analysis methods. We control for 35 aspects of study design and employ Bayesian model averaging to tackle the resulting model uncertainty. Our findings suggest that the definition of financial stability and bank competition used by researchers influences their results in a systematic way. The choice of data, estimation methodology, and control variables also affects the reported coefficient. We find evidence for moderate publication bias. Taken together, the estimates reported in the literature suggest little interplay between competition and stability, even when corrected for publication bias and potential misspecifications.
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Financial Development and Economic Growth: A Meta-Analysis
Havránek, Tomáš ; Horváth, Roman ; Valíčková, Petra
We analyze 1334 estimates from 67 studies that examine the effect of financial development on economic growth. Taken together, the studies imply a positive and statistically significant effect, but the individual estimates vary widely. We find that both research design and heterogeneity in the underlying effect play a role in explaining the differences in results. Studies that do not address endogeneity tend to overstate the effect of finance on growth. While the effect seems to be weaker in less developed countries, the effect decreases worldwide after the 1980s. Our results also suggest that studies using stock-market-oriented measures as a proxy for financial development tend to report larger positive effects on growth. We find little evidence of publication bias in the literature.
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Structural Reforms and Economic Growth: A Meta-Analysis
Babecký, Jan ; Havránek, Tomáš
This paper evaluates the impact of structural reforms, mainly liberalization and privatiza- tion, on economic growth. To provide stylized facts on how such reforms worked in the past, we quantitatively review 60 studies that estimate the relation between reforms and growth empirically. These studies examine structural reforms carried out in 26 transition and post-transition countries around the world. Our results show that a typical reform caused costs in the short run, but had strong positive effects on long-run growth. Reforms focused on external liberalization proved to be more beneficial than other types of reform in both the short and long run. The findings hold even after correction for publication bias and misspecifications present in some primary studies
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Transmission Lags of Monetary Policy: A Meta-Analysis
Havránek, Tomáš ; Rusnák, Marek
The transmission of monetary policy to the economy is generally thought to have long and variable lags. In this paper we quantitatively review the modern literature on monetary transmission to provide stylized facts on the average lag length and the sources of variability. We collect 67 published studies and examine when prices bottom out after a monetary contraction. The average transmission lag is 29 months, and the maximum decrease in prices reaches 0.9% on average after a one-percentage-point hike in the policy rate. Transmission lags are longer in large developed countries (25–50 months) than in new EU member countries (10–20 months). We find that the factor most effective in explaining this heterogeneity is financial development: greater financial development is associated with slower transmission. Moreover, greater trade openness in new EU member countries seems to be associated with faster transmission. Our results also suggest that researchers who use monthly data instead of quarterly data report systematically faster transmission. JEL
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Meta-analysis of methodological artifacts of the phylogenetic imbalance.
SMRČKOVÁ, Jana
The influence of possible methodological artifacts (e.g. type of data or tree construction methods) on the tree topology was evaluated. A total of 413 phylogenetic trees was downloaded from the tree repository TreeBASE. Three indices of topology imbalance were employed, namely, Fusco & Cronk index, weighted average, and Colless index. The study reveals that methodological artifacts have probably a weak influence on the tree shape. Therefore, patterns in tree balance could reflect macroevolutionary processess, not a methodological bias.
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