The Effect of Age and Anthropometric and Somatic Variables on Agility Performance in Adolescent Ice Hockey Players

Agility, one of the components that affect performance, is beneficial in invasion sports, such as ice hockey. This study aimed to assess the relationship between agility and pubescence in adolescent male ice hockey players. Agility and anthropometric and somatic data were evaluated in 60 male participants (age, 12.98 ± 1.44 years). Participants were divided into 5 groups according to age from 11 to 15 years (11y to 15y). Anthropometric and somatic variables were observed using a bioelectrical impedance device. Agility performance level was evaluated by T-Test and Edgren Side Step Test (EDGREN). Significance level was set at p ≤ 0.05. One-way analysis of variance was used to investigate mean differences. A significant effect of age was found for height, body weight, and skeletal muscle mass percentage. Tukey’s (HSD) post hoc test revealed significant differences in height and body weight between all age groups. The T-Test revealed significant differences between all groups, except between groups 11y and 12y, 12y and 13y, and 14y and 15y. EDGREN showed differences only between groups 11y and 13y and 11y and 15y. Significant Pearson correlations were found between all monitored variables and both agility tasks. Agility improves with age in adolescent male ice hockey players. EDGREN is suitable for testing agility skills in children from the end of middle childhood to early adolescence because it is less influenced by anthropometric and somatic variables. The T-Test should be used in testing agility in late adolescent and adult athletes when maturation is completed

Benchmarking of Selected Mining Enterprises

Bakalářská práce se zabývá benchmarkingem vybraných těžebních podniků, s největším podílem na objemu těžby a zpracování kamene v ČR. Teoretická část vychází z teoretických základů a literárních rešerší. Zde je vysvětlen pojem benchmarking, jeho kategorie, charakteristika a využiti pro podnik. Další část práce se zabývá nástroji finanční analýzy a matematicko-statistických metod, které jsou potřebné k vytvoření benchmarkingu. V praktické části jsou charakterizovány vybrané těžební podniky, na kterých je proveden benchmarking na základě nástrojů finanční analýzy a matematicko-statistických metod. Zde dochází k přímému porovnávání podniků, na základě veřejně dostupných dat a stanovení pořadí vybraných podniků na základě matematicko-statistické metody. V závěru práce jsou shrnuté poznatky, získané nastudováním tohoto tématu.The bachelor thesis deals with benchmarking of selected mining enterprises, with the largest share of stone mining and processing in the Czech Republic. The theoretical part is based on theoretical foundations and literary researches. Here is explained the concept of benchmarking, its category, characteristics and use for the enterprise. Another part of the thesis deals with the tools of financial analysis and mathematical-statistical methods, which are necessary for creation of benchmarking. The mining enterprises are selected in the practical part, where benchmarking is performed on the basis of tools of financial analysis and mathematical-statistical methods. There is a direct comparison of enterprises based on publicly available data and the ranking of selected enterprises based on the mathematical and statistical method. At the end of the thesis there are summarized knowledge gained by studying this topic.545 - Institut ekonomiky a systémů řízenívelmi dobř

HARDNESS OF NITRIDED LAYERS TREATED BY PLASMA NITRIDING

Stainless steels, particularly the austenitic stainless grades are widely used in many industries due to good corrosion resistance, but very poor mechanical properties as surface hardness and wear resistance limit its possible use. Plasma nitriding is one of the few ways to increase the surface hardness of these steels, even though this will affect its corrosion resistance. This paper focuses on the description of the mechanical properties of nitrided layers in the two most widespread austenitic stainless steels AISI 304 and AISI 316L. The microstructure and properties of nitrided layers were evaluated by metallography and microhardness measurement. Surface properties of nitrided steels were characterized by Martens hardness. The results show that plasma nitriding created very hard nitrided layers with thickness about 40 μm and microhardness about 1300 HV0.05. Surface hardness measurements have shown that the maximum values for both steels are about 8.5 GPa, but have different behaviour under higher loads, when the AISI 316L nitrided layer began to crack on the surface and sink

Are the incomes of agricultural households lagging behind? Evidence from Czechia

The aim of this article is to compare the income of agricultural households with the income of other economically active households in Czechia and to determine the extent to which a difference can be explained by the difference in household characteristics. The research was carried out on the basis of the Czech SILC survey (2005–2016). To determine the level of poverty of agricultural households, we used the Foster– Greer–Thorbecke poverty measures. To decompose the income gap, we used Blinder-Oaxaca decomposition in the modification for longitudinal data. The incomes of agricultural workers are lower compared to other sectors, and this difference was also reflected in the equalised household incomes. Households differ in the poverty rate, but do not differ in the depth of poverty. The income gap can be explained by the difference in household characteristics of only 20%, with education and the type of occupation having the most significant influence

Effects of Biochar Application on Winter Wheat (Triticum aestivum L.) Roots Under Long-Term Drought Conditions

The main objective of this paper was to evaluate the effect of applying biochar and activated carbon on winter wheat affected by drought in model laboratory conditions. Cultivation tests of the soil-microorganisms-plant (winter wheat) system were focused on understanding the interactions between microbial soil communities and experimental plants in response to specific cultivation measures, in combination with the modelled effect of drought. The containers were formed as a split-root rhizotron. In this container experiment, the root system of one and the same plant was divided into two separate compartments where into one half, biochar or activated carbon has been added. The other half without additives was a control. Plants favoured the formation of the root system in the treated part of the container under both drought and irrigation modes. In drought mode there was lower production of CO2, lower overall length and surface of the roots of winter wheat compared to variants in irrigation mode. The application of biochar and activated carbon, therefore, supported the colonization of roots by mycorrhiza in general. The Scientific merit of this paper was to investigate the possibility of mitigating the effects of a long-term drought on winter wheat through the application of biochar or the application of activated carbon.O

Application of Portable Force Platforms Equipped with a Device for Measuring Position and Orientation

With the development of modern technology for studying the movements of the human body, a large number of new measurement techniques are being applied. However, a complex and expensive device is not always the best one for personal requirements or for professional needs. We havedesigned and tested a new universal way to study the forces under the feet based on force platformsequipped with a device for measuring position and orientation. The device for measuring position andorientation is used to identify the relative positions of the two inexpensive force platforms in 3-D space. Knowledge of the relative positions and orientations of the force platforms allows us to adjust the two force platforms in 3-D space. The technique allows the force platform system for measuring and calculating the forces under the feet and the position of the center of pressure to be set up rapidly. The new technique, based on inexpensive portable force platforms equipped with a device for measuring position and orientation, is used and described for the first time here. This work attempts to describe potential ways of applying the technique

THE INFLUENCE OF FOOT ALIGNMENT ON KINEMATIC PARAMETERS OF GAIT IN BALLET DANCERS

The aim of this study was to assess the relationship between kinematic parameters and foot rotation relating to gait direction. Thirty-two professional ballet dancers (15 males, 17 females; age 26.8±5.6 years) participated in this research. Each participant performed five trials of gait at self-selected walking speed. Kinematic data was obtained using the optoelectronic system Vicon MX. Foot axis angle (°) was obtained by Footscan (RSscan International). Significant differences (p < 0.05) between the kinematic variables and foot axis angle were observed at knee flexion in the stance phase and ROM (range of motion) and maximum pelvic rotation in female as well as knee ROM in the frontal plane, and maximum pelvic obliquity and rotation in men. Significant differences between two groups of dancers with foot axis angle under and above 15 degrees were found for the knee and pelvic kinematic variables. This altered movement can lead to increased stress load on the joints of the lower limbs and predispose to injuries or early degenerative changes in the musculoskeletal system. Avoiding excessive foot external rotation during gait may reduce load on the musculoskeletal system and may prevent injuries

Kinematic chains in ski jumping in-run posture

The concept of kinematic chains has been systematically applied to biological systems since the 1950s. The course of a ski jump can be characterized as a change between closed and open kinematic chains. The purpose of this study was to determine a relationship between adjacent segments within the ski jumper’s body’s kinematic chain during the in-run phase of the ski jump. The in-run positions of 267 elite male ski jumpers who participated in the FIS World Cup events in Innsbruck, Austria, between 1992 and 2001 were analyzed (656 jumps). Two-dimensional (2-D) kinematic data were collected from the bodies of the subjects. Relationships between adjacent segments of the kinematic chain in the ski jumper’s body at the in-run position are greater nearer the chain’s ground contact. The coefficient of determination between the ankle and knee joint angles is 0.67. Changes in the segments’ positions in the kinematic chain of the ski jumper’s body are stable during longitudinal assessment. Changes in shank and thigh positions, in the sense of increase or decrease, are the same.Web of Science391736

Variability of spatial temporal gait parameters and center of pressure displacements during gait in elderly fallers and nonfallers: A 6-month prospective study

Considering that most of the falls in elderly population arise during walking, tests derived from walking performance would be desirable for comprehensive fall risk assessment. The analysis of spatial temporal parameters and the center of pressure displacement, which represents the interaction between the human body and the ground, would be beneficial. The aim of this study was to compare spatial temporal gait parameters and their variability and the variability of the center of pressure displacement between elderly fallers and nonfallers during gait at self-selected, defined and fast speeds. A prospective study design was used. At the baseline, measurements of ground reaction force during gait at self-selected, defined and fast walking speeds by two force plates were performed. In addition, the Tinetti balance assessment tool, the Falls Efficacy Scale-International and the Activities-Specific Balance Confidence Scale were used. Mean and coefficient of variation of spatial temporal gait parameters and standard deviations of center of pressure displacement during loading response, midstance, terminal stance and preswing phases were calculated. Comparison of the fallers and nonfallers exhibited no significant difference in clinical tool, scales or spatial temporal parameters. Compared to nonfallers’ increased variability of walking speed at self-selected and defined speed, step width at fast walking speed and center of pressure displacement during preswing phase in medial-lateral directions at defined walking speed was found in fallers. However, application of the Holm-Bonferroni procedure for multiple comparisons exhibited no significant effect of group in any of the gait parameters. In general, our study did not observe an effect of group (fallers vs. nonfallers) on variability of spatial temporal parameters and center of pressure movement during gait. However, walking speed, step width as well as standard deviation of COP displacement in the medial-lateral direction during preswing exhibited a certain potential for distinguishing between elderly fallers and nonfallers.Web of Science122art. no. e017199

The Occurrence of Ochratoxin A in Beers

In 2011–2014 the occurrence of ochratoxin A in beers from Czech retail network was studied. The beers included draught beers, lagers, special non-alcoholic beers and beer mixtures. Totally, 132 samples were analyzed. Ochratoxin A was detected in 81 % of the samples. Its concentration moved from 1.0–194.6 ng.l–1. Average ochratoxin A content in all samples in connection with the year of the occurrence was 14.2–39.9 ng.l–1. Ochratoxin A content was analyzed using the method of liquid chromatography with the fluorescent detection (UPLC/FLR)