Marek Brabec

Marek Brabec
The Czech Academy of Sciences | AVCR · Nonlinear Modelling

PhD

About

218
Publications
38,546
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2,592
Citations
Citations since 2016
108 Research Items
1762 Citations
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2016201720182019202020212022050100150200250300350
2016201720182019202020212022050100150200250300350

Publications

Publications (218)
Article
Full-text available
The advent of technological developments is allowing to gather large amounts of data in several research fields. Learning analytics (LA)/educational data mining has access to big observational unstructured data captured from educational settings and relies mostly on unsupervised machine learning (ML) algorithms to make sense of such type of data. G...
Article
Objective: To address the relationship between socioeconomic factors and age of menarche among Polish women born and reared in periods that varied considerably in environmental stresses: the Great Depression of the 1930s, the interval of World War II, and the interval of communist rule following World War II through the 1950s. Methods: The data...
Article
Full-text available
Apart from influencing the health of the worldwide population, the COVID-19 pandemic changed the day-to-day life of all, including children. A sedentary lifestyle along with the transformation of eating and sleep habits took place in the child population. These changes created a highly obesogenic environment. Our aim was to evaluate the current wei...
Article
PurposeBlade tip timing (BTT) is a promising non-contact method for the measurements of blade tip displacement in turbo-machinery. Despite the advantages, this method offers, one of its drawbacks is the highly under-sampled data measured. The quality of these data depends on the position of the probes in the engine casing. This work aims to determi...
Article
What are the effects of environmental and dispersal filters on vegetation in small and species‐rich fragments of temperate forests in which species richness increases along the edge‐interior gradient? Small fragments of thermophilic forests in central Bohemia, Czech Republic. Repeated vegetation surveys and seed rain sampling were conducted in 71 p...
Article
Full-text available
Background Owing to the COVID-19 pandemic, the Swiss goverment imposed a shutdown twice, which may have changed diet and physical activity. Regarding the question of weight change during the pandemic, little information based on measured weight data is available. We aimed to investigate whether the body mass indices (BMIs) of young Swiss men after...
Article
Blade tip timing (BTT) is a promising non-contact method for the measurements of blade tip displacement in turbo-machinery. Despite the advantages, this method offers, one of its drawbacks is the highly under-sampled data measured. The quality of these data depends on the position of the probes in the engine casing. Thus, the present work proposes...
Preprint
Full-text available
Inter-rater reliability (IRR), which is a prerequisite of high-quality ratings and assessments, may be affected by contextual variables such as the rater's or ratee's gender, major, or experience. Identification of such heterogeneity sources in IRR is important for implementation of policies with the potential to decrease measurement error and to i...
Article
Full-text available
It is important to study precipitation chemistry to comprehend both atmospheric and environmental processes. The aim of this study was the reconstruction of daily concentration patterns of major ions in precipitation from samples exposed for longer and differing time periods. We explored sulphates (SO42−), nitrates (NO3−) and ammonium (NH4+) ions m...
Article
Factors affecting the seasonal succession of plankton communities in freshwater temperate lakes have been thoroughly studied for decades. However, there are still relatively few data describing the winter season patterns in detail, as the focus has been mostly on spring to autumn conditions. Ice cover is often the crucial factor limiting light avai...
Article
Full-text available
Reservoirs interrupt natural riverine continuity, reduce the overall diversity of the environment, and enhance the spread of non-native fish species through suitable environments. Under favourable conditions, invasive species migrate to tributaries to benefit from local resource supplies. However, the changes in physical conditions in reservoirs th...
Article
Animal behaviour interacts with various relationships within biota, and its variation among individuals may cause bias in behavioural research because of its impact on sampling efficiency. In this study, we simultaneously recorded fish behaviour during the reproductive season by passive telemetry and sampled a fish population using an active sampli...
Preprint
Background: Due to the COVID-19 pandemic, the Swiss Federal Council imposed a shutdown twice, which may have changed dietary and physical activity habits. On the question of weight change during the pandemic, there is little information based on measured weight data. In this study, we investigate whether the body mass index (BMI) of young Swiss men...
Article
The monitoring of the blades in bladed disk assembly is done via a continuous determination and analysis of the blade dynamics, which is mostly subjected to different types of excitation forces inducing the synchronous and asynchronous vibration of the blades. These vibrations can cause fatigue and crack of the blade, which can damage the overall t...
Article
Full-text available
Objectives: Smoking-related mortality varies over different social, environmental, and policy contexts. However, spatial patterns, examined at a small area level, have been seldom considered. Therefore, the study provides a detailed analysis of socio-spatial inequalities in premature mortality related to smoking in the contemporary Czech adult popu...
Article
Full-text available
The glycemic response to ingested glucose for the treatment of hypoglycemia following exercise in type 1 diabetes patients has never been studied. Therefore, we aimed to characterize glucose dynamics during a standardized bout of hypoglycemia-inducing exercise and the subsequent hypoglycemia treatment with the oral ingestion of glucose. Ten male pa...
Article
The ignition delay is an important parameter which characterizes the initiation of combustion process and consequently its development in Diesel engines. This parameter mainly depends on chemical factors which are related to the fuel structure and its properties and also on physical factors which are related to the engine operating conditions. The...
Article
Fog is an important atmospheric phenomenon highly relevant to ecosystems and/or the environment. Two essential prerequisites of fog formation are the presence of fog condensation nuclei and water in the atmosphere. The aim of our study was to examine in detail how fog occurrence is influenced by water areas in the immediate vicinity of the fog obse...
Article
The hydropeaking regime below hydropower facilities represents a serious threat to riverine fauna and may cause declines in populations living under its influence. However, the knowledge on direct fish responses to the threat of hydropeaking is limited. Here, we aimed to test whether the hydropeaking generated 12 km upstream may have a negative eff...
Article
The ketogenic diet (KD) is an effective treatment for intractable epilepsy in children. Hypoglycemia can be one of its side-effects, which is considered to be present mainly during the introductory phase of KD. Continuous glucose monitoring in a 6-year old non-diabetic child treated with KD for more than 8 months revealed long periods of asymptomat...
Article
Childhood obesity is a serious global health problem. Waist circumference (WC) and waist-to-height ratio (WHtR) reflect body fat distribution in children. The objectives of this study were to assess WC and WHtR in 7-year-old children and to determine body mass index (BMI), WC, and WHtR differences in children from 10 selected countries across Europ...
Article
Full-text available
Objectives This paper sought to evaluate the occurrence of decompression sickness (DCS) after the application of a patent foramen ovale (PFO) screening and risk stratification strategy. Background PFO is associated with an increased risk of DCS. Recently, transcatheter closure was reported to reduce DCS occurrence in divers with a high-grade shunt...
Article
Full-text available
Fibroblast activation protein (FAP) is a membrane-bound protease that is upregulated in a wide range of tumours and viewed as a marker of tumour-promoting stroma. Previously, we demonstrated increased FAP expression in glioblastomas and described its localisation in cancer and stromal cells. In this study, we show that FAP+ stromal cells are mostly...
Article
The germinability of buried seeds changes with time, and the direction and periodicity of these changes differ among plant species. In 116 abundant dicotyledoneous herb species, we investigated the changes in seed germinability that occurred during the 2-year period following burial in the soil. We aimed to establish differences between seeds colle...
Article
Most studies addressing heat in urban environments focus on thermal conditions and neglect the mental component of thermal comfort. This study employs mental maps to analyse thermal (dis)comfort in the medium-sized Czech cities of Olomouc and Plzeň in summer. Locations of “mental hotspots” are identified particularly on busy streets, at transport h...
Article
Wind speed is involved in multiple scales physical phenomena and depends on specific features, that are not always easy to simulate numerically. Alternative solution that combines the physical advantages provided by numerical weather prediction (NWP) simulations and statistical models is investigated for wind speed forecast. Several aspects that in...
Article
Full-text available
The paper illustrates a fundamentally different approach applied to Blade Tip-Timing analysis in the background of works performed through the long history of this method. New innovative approach is based on the precise separation of measured data that was published in previous works. In this respect, the construction of the signal profile is inten...
Article
Thermal comfort in public spaces, as an important factor in the quality of life, has been strongly affected by manifestations of climate change. City authorities are under pressure to adapt their approaches to the urban environment. This study investigates thermal sensation in public spaces in four Czech cities. Biometeorological measurements were...
Article
Fog is influenced by numerous factors, including forests. The aim of our study was to examine in detail the extent to which forests affect fog. We hypothesised that: (i) fog incidence is affected by forests, (ii) the forested area in the station’s neighbourhood is a factor influencing fog incidence, (iii) the influence on fog differs between conife...
Article
Full-text available
High reproductive performance is the key attribute of male fitness, especially due to the high reproductive skew among the males of most animal species. Males of long-lived iteroparous species have opportunities to improve upon their previous reproductive attempts with increasing age. We collected individual-specific reproductive behaviour and age...
Article
The bonding performance of dental adhesives is most frequently evaluated using the micro-tensile bond strength (μTBS) test. Despite lacking evidence, peripheral specimens are often discarded to avoid regional variability. This study, therefore, examined whether μTBS to central and peripheral dentin differed. Dentin surfaces of extracted human molar...
Preprint
Thermal comfort in public spaces, as an important factor in the quality of life, has been strongly affected by manifestations of climate change. City authorities are under pressure to adapt their approaches to the urban environment. This study investigates thermal sensation in public spaces in four Czech cities. Biometeorological measurements were...
Book
Full-text available
Kniha je zaměřena na regresní modely, konkrétně jednorozměrné zobecněné lineární modely (GLM). Je určena především studentům a kolegům z biologických oborů a vyžaduje pouze základní statistické vzdělání, jakým je např. jednosemestrový kurz biostatistiky. Text knihy obsahuje nezbytné minimum statistické teorie, především však řešení 18 reálných přík...
Article
Fog is a very complex phenomenon, relevant to both atmospheric physics and chemistry, contributing to the atmospheric inputs of both nutrients and pollutants to the environment. Fog occurrence is affected by numerous factors. The aim of this study is to examine the effects of terrain on fog occurrence. Namely, we studied in detail how altitude, slo...
Preprint
Full-text available
The advent of technological developments is allowing gathering large amounts of data in several research fields. Learning analytics/educational data mining (LA/EDM) has access to big observational unstructured data captured from educational settings and relies mostly on unsupervised machine learning algorithms to make sense of such type of data. Ge...
Preprint
The arrangement of the Blade Tip-Timing's (BTT) sensors is delicate and important in order to extract useful information on the blade's vibration signal. Thus, this article proposes a simple approach for the determination of the optimal probes positioning based on the minimization of certain characteristics related to the measurement matrix (condit...
Article
Full-text available
Understanding of habitat favourability has wide relevance to the invasion biology of alien species. We studied the seasonal dynamics of the alien ladybird Harmonia axyridis (Coleoptera: Coccinellidae) in monoculture Scots pine forest stands in southwest Slovakia, Central Europe, from April 2013 to March 2015. Adult H. axyridis were collected monthl...
Article
Objectives: A competing risk (CR) model distinguishing adhesive, cohesive and mixed failures as competing events was used for the analysis of micro-tensile bond strength (μTBS) data and compared with a conventional failure mode non-distinguishing survival model. Methods: Fifty human molars were bonded using five universal adhesives (n = 10) and...
Article
Full-text available
A new and general approach is proposed for interpolating 6-h precipitation series over large spatial areas. The outputs are useful for distributed hydrological modelling and studies of flooding. We apply our approach to large-scale data, measured between 2014 and 2016 at 159 weather stations network of Meteo Romania, using weather radar information...
Chapter
Full-text available
Estimating the inter-rater reliability (IRR) is important for assessing and improving the quality of ratings. In some cases, the IRR may differ between groups due to their features. To test heterogeneity in IRR, the second-order generalized estimating equations (GEE2) and linear mixed-effects models (LME) were already used. Another method capable o...
Article
Ambient or ground-level ozone (O3), a key player in atmospheric chemistry, has been studied extensively throughout the world in recent decades due to its harmful effects on human health and the environment. The aim of this study is to examine in detail the time patterns of O3 in the Czech Republic, a Central European country with a long–term histor...
Article
Full-text available
IntroductionPhysical fitness benefits health. However, there is a research gap on how physical fitness, particularly aerobic endurance capacity and muscle power, is influenced by residential altitude, blood parameters, weight, and other cofactors in a population living at low to moderate altitudes (300–2100 masl).Materials and Methods We explored h...
Article
Full-text available
The Harlequin ladybird Harmonia axyridis Pallas, native to eastern Asia, is an invasive, non-native species that has recently achieved an almost worldwide distribution. A conspicuous feature of this species is colour polymorphism of the elytra. In its native area, the populations consist of a recessive non-melanic morph, several dominant melanic mo...
Article
Full-text available
A reliable and practically useable method for gap filling in hourly Spinning Enhanced Visible and Infrared Imager (SEVIRI LST) data using ERA5 Land Skin Temperature (ERA5ST) co-variate and additional easily accessible data (elevation, time, solar radiation info) is proposed. The suggested approach provides estimates to all weather conditions and it...
Article
Full-text available
The sunshine duration data is analysed here from a new perspective, different from the traditional ones. The study is focused on pairs of periods of shining sun (called clear periods) followed by periods with the sun covered by clouds (called dark periods). Their statistical and sequential properties are illustrated by using results obtained from s...
Preprint
Estimating the inter-rater reliability (IRR) is important for assessing and improving the quality of ratings. In some cases, the IRR may differ between groups due to their features. To test heterogeneity in IRR, the second-order generalized estimating equations (GEE2) and linear mixed-effects models (LME) were already used. Another method capable o...
Article
Full-text available
The relationship between the number of cereal aphids in flight (recorded by a national grid of suction traps in the Czech Republic) and their occurrence on winter wheat (in Prague) was established between 1999–2015. The flight of all the species was bimodal. Except for Rhopalosiphum padi, whose flight activity peaked in autumn, > 80% of individuals...
Article
Fog is a very important and complex atmospheric phenomenon of the utmost importance for the environment and for human society. For practical reasons, fog occurrence is observed regularly at meteorological stations worldwide. Decreasing trends in fog frequency reported from numerous regions have been often associated with either decreasing pollution...
Article
Full-text available
The aim of this study is to evaluate the prevalence of overweight and obesity in a sample of children who were exclusively or predominantly breastfed for at least 6 months compared to Czech references that were constructed based on a representative sample of children, regardless of their mode of feeding. Between 2008 and 2011, a longitudinal study...
Article
A long-distance edge effect influences structure of species-rich plant communities in temperate forest fragments surrounded by an agricultural landscape in Central Europe. Though the edge effect may be an aggregate of many environmental conditions, the thermal gradient from the forest edge to the forest interior deserves particular attention due to...
Article
Full-text available
Household consumption of natural gas is usually considered to be quite stable as cooking, space, and water heating belong to basic needs. The improvement of technologies together with possibilities of switching to alternative sources can, however, lead to a decreasing consumption trend. Knowing more about such trend, especially of its spatial distr...
Article
Full-text available
The aim of our study was to identify the factors substantially affecting day-to-day variability in O3 concentrations in Czech mountain forests and to describe their influence in detailed, quantitative way. We examined the effects of meteorology and ambient NOx recorded in regular long-term continuous monitoring at five mountain forest sites represe...
Article
Full-text available
The mating behaviour of Pyrrhocoris apterus in the laboratory is well studied, but little is known about it under natural conditions. In natural populations in Central Europe, overwintered adults start copulating in March and continue until their death. Caged females, kept under natural conditions in the permanent presence of males, copulated repea...
Article
Effective indicators for biodiversity hotspots and refuges of threatened forest species could help with efforts to mitigate the decline of European forest's biodiversity. ʻAncient forest species' (AFS, i.e. a group of forest vascular plant species that rely on forest continuity) were previously noted as possible indicators of biodiversity hotspots....
Article
This paper deals with the measurement and assessment of rotor speed instabilities. Mean attention is paid to measurements on turbine rotors while using the Blade Tip-Timing Method. The problematic was investigated on the model test turbine wheel of the Institute of Thermomechanics. A novel signal processing method, which consists of a combination o...
Article
Full-text available
To determine the causes of the variation in the seasonal dynamics of Harmonia axyridis (Pallas) in Central Europe, numbers of adults and larvae of this invasive species were recorded on trees (Acer, Betula, Tilia) throughout the growing seasons from 2011 to 2016. Each year beetles were collected every two weeks, using a standardized sweeping method...
Article
Disentangling the importance of developmental vs. environmental drivers of variation in forest biomass is key to predicting the future of forest carbon sequestration. At coarse scales, forest biomass is likely to vary along major climatic and physiographic gradients. Natural disturbance occurs along these broad biophysical gradients, and depending...
Article
Harmonia axyridis (Pallas), an invasive non-native species in central Europe, can outcompete other aphidophagous species. The distribution and abundance of H. axyridis vary depending on different host plants, and its effects on native coccinellid communities may change accordingly. The distribution and abundance of coccinellids in central Europe (5...
Conference Paper
We first analyze some features of numerical weather predictions (NWP) for global solar radiation and notice that they are undersmooth. This finding opens a way to improvements via various smoothing strategies. Then we introduce a statistical modeling framework based on modern semiparametric regression. We use a numerical weather prediction (NWP) mo...