59 research outputs found
Sound Generation by Hydrogen/Methane Premixed Flames
No full text© 2022 Jen Zen HoHydrogen produced by renewable energy is a promising alternative fuel that can be used to decarbonise the electricity generation sector. Mixing hydrogen with natural gas can smoothly transition current energy generators towards producing less greenhouse gas emissions while mitigating the challenges faced by burning pure hydrogen. However, there are challenges in the usage of hydrogen because it has very different flame characteristics compared to conventional fuels used in gas turbines such as natural gas.
One of the major challenges faced by combustor designers is thermoacoustic instability. This instability occurs when the acoustics of the combustor couple with the flame and generate very loud high frequency pressure oscillations that can damage the combustor and reduce the lifespan of equipment. Hydrogen addition to the fuel can initiate thermoacoustic instability, hence it is important to understand the impact that hydrogen addition has.
Thermoacoustic instabilities are closely linked to sound generation by flames. In addition, many combustors produce loud noise which are subject to stringent regulations. Predicting the sound generated by flames is key to designing safer and quieter combustors. However, there is little information in the literature on the effect of hydrogen addition on the sound generated by flames.
This thesis will utilise high fidelity simulations, specifically Direct Numerical Simulations (DNS), to simulate turbulent premixed jet flames with different hydrogen/methane fuel content. Firstly, planar one-dimensional (1D) annihilation events are simulated for different hydrogen/methane mixtures and the pressure waves generated by these events are compared. It is found that the flames fuelled with hydrogen/methane mixtures undergo a three-stage annihilation event, with the first stage generating long-wavelength pressure waves. This first stage is not present in pure hydrogen or pure methane fuelled annihilation events. These simulations are used to develop a reduced chemical mechanism with low computational cost, enabling three-dimensional (3D) DNS of the turbulent premixed jet flames.
The 3D DNSs are then performed and the sound generated by the flames is compared for different hydrogen/methane fuel mixtures. The dependence of the sound on the flame dynamics and the flame stretch, displacement speed and curvature is characterised. The Sound Pressure Level (SPL) of the sound waves generated by annihilation events is found to increase with hydrogen content in the fuel. This effect is due to the increase in laminar flame speed with hydrogen addition.
In annihilation events, heat release rate fluctuations are the dominant source of noise. However, there has not yet been a full comparison of all noise sources in a turbulent premixed jet flame. In this work, an acoustic analogy is used to find the contribution of all physical mechanisms by which sound is generated in the flame. It is found that the heat release rate fluctuations and turbulence are the principal sources of noise for all cases. To retrieve the pressure fluctuations from turbulent eddies, the superposition of three different sources, specifically the (a) Lighthill stress tensor source, (b) entropy inhomogeneity source, and the (c) surface contribution, must be used. These three sources are found to be intrinsically linked with each other. In addition, the energy transport by mass diffusion is found to be an important source of sound when hydrogen and methane are equally mixed in volume, and unimportant when one fuel is dominant
[[alternative]]Experiences of Zen Meditators and Revelations of Emptiness: Research into a Mode of Psychotherapy
No full text[[abstract]]Experiences of Zen Meditators and Revelations of Emptiness:
Research into a Mode of Psychotherapy.
ABSTRACT
The goal of this research is to investigate the meditation experiences of Zen practitioners by adopting a qualitative analysis. Using the results obtained with this method, I will explain how the revelation of a Zen meditator about the true nature of emptiness can be one of the elements of an effective psychotherapy.
The subjects involved in this research are seventeen Buddhist Zen meditators. Their ages range from 25 to 65, on average they have 7 years of meditation experiences. First of all, the subjects were asked to provide their diaries describing anywhere from one to ten meditation experiences. Then, the interviews were conducted, and the results were organized into notes. I, while repeatedly reading the interview notes, felt myself released and let myself be questioned by the topic of the interview. Based on my background of knowledge, I had responses to the questions of the interview. Using this kind of investigative method, the main theme subtly concealed in the data directed me, and took a shape of its own. It became clear that the main theme of the study is that the revelation attained about the nature of emptiness is one of the elements leading meditators to psychological health.
From the data accumulated from the seventeen research subjects, this research yielded the following results:
1) In Zen meditation, because of the level of concentration achieved, mental stimulation was reduced, emotions became more even and steady, and one could consciously regulate the circulation of bodily energy. Following such regulation, Zen practitioners’ emotions became purified, their physical sensitivity increased accordingly, as did their ability to be aware of their mental states. Self-control was increased, and subjects could concentrate themselves easily. Powers of understanding were advanced, and the ability to accept things as they are was raised.
2) Through meditation, Zen practitioners realized that things are always multifaceted, and never with any single and independent nature. They realized the inconstancy of their thoughts and feelings, as well as how attachment leads to the production of pain. Finally, they had revelations about the nature of emptiness.
3) Based upon their revelations of the nature of emptiness, meditators were able to let go of their attachments to things, even to the point where they were able to abandon the searches their minds were constantly engaged in. They concentrated upon their method of meditation, quieting their minds and sitting. Thus were meditators able to enjoy many psychological benefits produced by Zen sitting meditation.
4) Based on meditation, Zen cultivators were able to transform the emotions that result from stimulation and achieve a sense of stability, of standing in the center. For this reason, cultivators were able to look at things from an objective point of view without being bothered by their emotions. Based on their revelations of the nature of emptiness, on the other hand, cultivators were able to regard things directly from an objective perspective and reduce the emotions arisen from attachments. Thus were they better able to avoid dealing with things out of emotional impulses. The revelation of the nature of emptiness helped people face stimulation and be able to maintain an objective and centered attitude, in order to deal with things coldly. This ability is of great assistance in dealing with the many types of stimulations that a modern person faces in his daily life.
This research reach several conclusions based upon the data gathered from interviews with Zen practitioners as well as upon the results of analysis. The point is raised that the revelation of a Zen meditator about the true nature of emptiness is one of the elements of an effective psychotherapy.
Physical dance performance: An investigation into the development of a performance technique based on the integration of certain Korean dance technique and contemporary Western styles of dance and physical theatre
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 04/10/2001.This development of a performer practice that integrates elements of traditional Korean dance technique and Western forms of physical theatre and contemporary dance is based on an approach to internal understanding and external execution. Central to the work is the concept of body energy, or Ki. This ancient Eastern term is translated into a contemporary practice that enables a performer to engage mental and physical training. Breath and the use of breath in performing are the principal means of achieving this level of engagement
Bedeutung und Bekämpfung von Schadinsekten an Winterweizen und Winterraps in Schleswig-Holstein, 1999-2001, und der Trend der Insektizid-Behandlungen von 1999-2004
No full textIn the average of 1999 to 2004 winter wheat covered 64 % of the agricultural land of Schleswig-Holstein (331.000 ha), winter oilseed rape 31 %. These two important crops (covering 95 % of the acreage) were attacked in 1999 to 2001 by a) wheat: cereal leaf beetles (Oulema spp.Col., Chrysomelidae) and by cereal aphids (mainly Sitobion avenae and Metopolophium dirhodum; Hom., Aphididae; b) Oilseed rape: by pollen beetles (Meligethes aeneus F.; Col., Nitidulidae) and by the cabbage seed weevil Ceutorrhynchus assimlis (Payk.) (Col., Curculionidae). Studies (with six field experiments per crop, at two sites, 1999 to 2001) were done by the first author in the course of the work on a PhD thesis (Kirch 2006) to clarify the economic importance of these pests, and to look for the validity of the action thresholds published. Additionally, 51 farmers were inquired for their insecticide use, 1999 to 2004.Winterweizen bedeckte 1999-2004 64 % der Ackerfläche Schleswig-Holsteins, Winterraps 31 %. Die wichtigsten Schädlinge an Winterweizen waren die drei Getreideblattlausarten (Hom., Aphididae)(Sitobion avenae und Metopolophium dirhodum, selten Rhopalosiphum padi) und die beiden Oulema-Arten (Getreidehähnchen)(O. melanopus und O. lichenis) (Col., Chrysomelidae). An Winterraps traten im Untersuchungszeitraum auf: Meligethes aeneus (F.) (Rapsglanzkäfer) (Col., Nitidulidae) und Ceutorrhynchus assimilis (Payk.) (Kohlschotenrüßler) (Col., Curculionidae). In beiden Kulturen wurden sechs Feldversuche durchgeführt, mit frühen und späten Insektizid-Applikationen (an je zwei Standorten, mit vierfacher Wiederholung). Bei Weizen waren die Parzellen 50 m² groß, bei Raps 90 m². Bei Winterweizen zeigten beide Schaderreger-Gruppen negative Einflüsse auf den Ertrag, wenn sie nicht bei Bekämpfungsschwellen bekämpft wurden. Sowohl der Getreidehähnchen - als auch der Blattlausbefall waren signifikant negativ mit dem Ertrag korreliert. Die ökonomische Auswertung ergab, dass im Untersuchungszeitraum – bei Beachtung der Bekämpfungsschwellen - die frühe Bekämpfung der Getreidehähnchen-Larven wirtschaftlicher war als die spätere der Getreideblattläuse. Bei Winterraps erwies sich die Bekämpfung des Kohlschotenrüsslers als ertraglich und ökonomisch vorteilhaft, selbst ohne Auftreten von Dasineura brassicae (Winn.), der Kohlschotenmücke. Die Bekämpfung des Rapsglanzkäfers hingegen war nur in einem von sechs Versuchen ertragsmäßig und ökonomisch erfolgreich. Die Probleme bei diesem Schädling sind 1. die zu niedrige Bekämpfungsschwelle und 2. die Resistenz gegenüber synthetischen Pyrethroiden. Wurden in Schleswig-Holstein 1999 75.000 ha Ackerfläche mit Insektiziden behandelt (22.7 % AF), stieg die Fläche bis 2004 auf 220.000 (66.5 % AF). Die Anteile der einzelnen Wirkstoffe haben sich verändert
Indo-European vocabulary in Old Chinese : a new thesis on the emergence of Chinese language and civilization in the late Neolithic age
No full textThis study is a much expanded version of the paper I read at the XXXII International Congress for Asian and North African Studies on August 28, 1986 in Hamburg (Germany). Contents 1. Recent developments in the field of historical linguistics 2. Monosyllabic structure of Chinese words and Indo-European stems 3. Tonal accents of Middle Chinese 4. Preliminaries on the comparison of consonants and vowels 5. Some IE stems corresponding to Chinese words of entering tone 6. Middle Chinese tones and final consonants of IE stems 7. Some IE stems corresponding to Chinese words of rising tone 8. Some IE stems corresponding to Chinese words of vanishing tone 9. Some IE stems corresponding to Chinese words of level tone 10. Reconstruction of Middle Chinese vocalism according to Yün-ching 11. Old Chinese vocalism 12. Vocalic correspondences between Chinese and IE 13. Initials of Old Chinese 14. Initial consonant clusters in Old Chinese as seen from IE-stems 15. Proximity of Chinese to Germanic 16. Relation of Old Chinese to neighboring languages 17. Emergence of Chinese Empire and language in the middle of the third millennium B.C. Appendix * Abbrevations * Bibliography * Rhyme Tables of Early Middle Chinese (600) * Rhyme Tables of Early Mandarin (1300) * Word Index o English o Pinyin In 1786, just over two hundred years ago, comparative historical linguistics was born, when Sir William Jones (1746-1794) discovered the relationship between Old-Indian Sanskrit, Greek, and Latin. Since then, the emerging Indo-European philology has thrown much light on the early history of mankind in Eurasia. During the past two hundred years, many suggestions were also made in regard to relationships of Indo-European to other languages such as Semitic, Altaic, Austronesian, Korean etc., but Indo-Europeanists commonly rejected such attempts for want of convincing evidence. As to Chinese, Joseph Edkins was the first to advance the thesis of its proximity to Indo-European. In his work China's Place in Philology. An Attempt to show that the Language of Europe and Asia have a Common Origin (1871) he presented a number of Chinese words similar to those of Indo-European. In his time, Edkins' thesis seemed bold and extravagant. But today, more than a hundred years later, we are in a much better position to carry out a comprehensive and well-founded comparative study. Since the end of the nineteenth century, many Sinologists have been engaged in reconstruction of the mediaeval and archaic readings of Chinese characters. Among them, Karlgren (1889-1978) was the most successful, and in 1940 he published a comprehensive phonological and etymological dictionary entitled Grammata Serica. In the meantime, the Indo-Europeanists Alois Walde (1869-1924) and Julius Pokorny (1887-1970) were devoting themselves to the compilation of a useful etymological dictionary. The result was the Indogermanisches Etymologisches Wörterbuch by Pokorny (1959) which provides a solid basis for our lexical comparisons. Soon thereafter, some Sinologists made use of the two dictionaries by Karlgren and Pokorny to compare Chinese and Indo-European words. In 1967, an unaffiliated German scholar, Jan Ulenbrook, published an article "Einige Übereinstirnrnungen zwischen dem Chinesischen und dem Indogermanischen", in which he claimed that 57 words are related. Shortly afterwards, Tor Ulving of the University of Goteborg, Sweden, wrote a review of this article framing the title as a question: "Indo-European elements in Chinese?" While working on his thesis on word families in Chinese, Ulving compiled for his own use two dictionaries: "Archaic Chinese - English" and "English - Archaic Chinese", and discovered thereby 238 Chinese words similar to Indo-European roots. In spite of this considerable number of word equivalents, however, Mr. Ulving became discouraged and, as he told me in his letter of April, 1986, has given up his researches in this field. The skepticism, common among Indo-Europeanists in regard to comparative studies with other languages, is largely based on the dogmatic opinion that only morphology is relevant but not vocabulary. Since the typology of Chinese seems to preclude a cognate relation to Indo-European, they are inclined to discard any lexical correspondences as merely accidental or onomatopoetic. Besides, prehistorical contacts and mixtures between these languages seem not conceivable, as the Indo-Europeans are supposed to have originated in Northern Europe or at best in the Central Asian steppe, thousands of miles away from East Asia. Hence, any research into a relationship between Old Chinese and Indo-European languages would be but futile from the outset. Yet there are also opposing views among Indo-Europeanists. Investigations into Germanic languages and the oldest Indo-European language, Hittite, led some of them to a critical revision of the prevailing conception about a Proto-Indo-European. Hermann Hirt (1934) for instance states: "Inflexion of Indo-European languages is due to a relatively late development, and its correct comprehension can be achieved only by proceeding from the time of non-inflexion." And Carl Karstien (1936) holds the opinion that "Chinese corresponds most ideally to the hypothetic prototype of Indo-European." Regarding vocabulary, there are striking similarities in the monosyllabic structure of the basic words. In modern German and English, all the words of everyday speech are monosyllabic and their stereotypical structure is: initial consonant(s) + vowel(s) + final consonant(s). The same word structure is valid for Chinese as well. It is fundamentally different from the disyllabic structure of Altaic words and from the triconsonantal-disyllabic structure of Semitic words. Characteristic of the monosyllabic word structure is, besides, the complexity of the syllable nucleus, which consists of different vowels and vowel clusters in contrast to the monophthongal vocalism of polysyllabic words. Another objection raised to comparisons between Chinese and Indo-European is the existence of tonal accents in Chinese. Since most modern Indo-European languages have only expiratory accents, Chinese is considered to be a highly exotic language. Yet, even in Chinese, the use of tonal accents as a means of lexical differentiation is a result of comparatively recent development in the long history of Chinese language, the earliest monuments of which date back to 1300 B.C. (cf. Chang 1970, p.21). Unknown to Old Chinese, the existence of tonal accents was for the first time mentioned in the 5th century by Shen Yüeh (441-513). In Middle Chinese (Mch.) there were four tone categories: A P'ing-sheng 平 a level tone (which developed into Mandarin tone 1 or 2). B Shang-sheng 上 a rising tone (Mandarin tone 3). C Ch'u-sheng 去 a vanishing, i.e. falling tone (Mandarin tone 4). D Ju-sheng 入 an entering tone with a staccato effect, the word being abruptly stopped by a final consonant -p, -t, -k. (In Early Mandarin the words of this tone lost their final consonant and were distributed among the tones 2, 3 and 4, respectively according to the phonation of initials). In Middle Chinese, words of the entering tone were the only group which still preserved the final stops and therefore a close syllabic structure. So they are most appropriate for convincing comparisons with monosyllabic Indo-European word stems. The final stops -p, -t, -k of the entering tone are nowadays still extant in daily speech of several dialects in South China as well as in Chinese borrowings in Japanese, Vietnamese and Korean. As a speaker of a Taiwan dialect of Minnan origin, I could immediately identify some Indo-European stems with corresponding Chinese words. Besides, the command of Japanese and German was also a great help for this study. In the following lists I have chosen a number of Indo-European stems which are phonetically and semantically equivalent to Chinese words. Correspondences in initial and final consonants refer to the points of articulation, thus we have equations: IE labials = Old Chinese labials, IE dentals = dentals, IE l, r = dentals (cf. p. 31); Ø, i (final and medial) IE velars = velars and laryngeals, and occasionally (the so-called "satem"-forms) IE velars = dental sibilants and affricates. Regarding the manner of articulation, there are no regular correspondences between Indo-European and Chinese consonants like Grimm's law which is valid among Indo-European dialects to a certain extent. But this is not astonishing, since in Old Chinese the alternation of initials in voicing was a conventional means of creating new words from one basic form. The rules of vocalic correpondences among Indo-European dialects are quite complex. Vowels permanently change their qualities from one language to another, and from time to time within one language also, as is well known from the history of English pronunciations. Generally, the vocalism of Old Greek is taken as the standard for Proto-Indo-European. Old Chinese vowels corresponds nearly (cf. p. 30), but the details about the reconstruction of Middle and Old Chinese vocalism will be treated later (pp. 26-30). For the moment, it is necessary to notice in advance that the stem of ablauting Germanic verbs is the form of preterite or noun, rather than that of infinitive as assumed hitherto. Therefore, in some cases I must slightly modify the basic vowel of verbal stems given in Pokorny, in order to get better basis for comparison. As Old Chinese verbs were non-flexional, they might probably have preserved the original vowel the best
Biotransformace methoxfenidinu houbou Cunninghamella elegans, fotografie mycelií kultivovaných na ztužených médiích na membránách a bez membrán
No full text<p>Tento soubor dat je Příloha č. 1 bakalářské práce "Biotransformace methoxfenidinu houbou <em>Cunninghamella elegans</em>". Soubor obsahuje fotografie mycelií <em>C. elegans</em>, kultivovaných na různých typech ztužených médií (A1, A2, A1P, A2P, PD, SM) s membránami a bez membrán, vyfocených každých 24 h po dobu 5 dní ode dne, kdy byl pokus zahájen, tzn. první fotografie byla pořízena v čase 0 h. Kultivace probíhala ve tmě při 24 °C.</p>
<p>Kmen <em>C. elegans</em> NRRL 1393 byl získán ze sbírky ATCC.</p>
<p>Kultivační média: A1, A2 = syntetická média, A1P, A2P = syntetická média (A1, A2), při jejichž přípravě byl MgSO4 přidán po sterilizaci, PD = bramborovo-glukosové médium, SM = sladinovo-mladinové médium</p>
<p>Dokumentační zařízení: UVIdoc HD2 (Uvitec Cambridge). Parametry nastavení dokumentačního zařízení: zvětšení 25×, clona F2, délka expozice 12 ms</p>
<p>Pojmenování fotografií: TypMedia-Replikát-Hodiny.tif</p>
<p>Jednotlivé fotografie jsou pojmenované podle typu média, čísla opakování (pokus byl proveden v triplikátech) a času, kdy byla fotografie pořízena. Např. A1-1-24 je mycelium <em>C. elegans </em>na ztuženém A1 médiu, replikát 1, kultivované 24 h.</p>
Assessment of the LES-FGM framework for capturing stable and unstable modes in a hydrogen / methane fuelled premixed combustor
No full textThe main objective of this paper is to assess the capability of compressible Large Eddy Simulations (LES) to capture azimuthal combustion instability. The thickened flame model coupled with Flamelet Generated Manifold (FGM) tabulated chemistry is used as the combustion model. LES of an annular combustor is performed for five cases featuring stable and unstable combustion of hydrogen-methane mixtures. The unstable modes feature azimuthal instabilities and this annular combustor is used to test the LES-FGM framework. A consistent methodology is applied across all cases. It is found that LES predicts azimuthal modes for stable cases but these modes are weak and intermittent with pressure fluctuation amplitudes within the order of experimental noise. In addition, the unstable cases capture azimuthal modes that have approximately the same frequency as that of the experiment though the amplitudes of the modes are over-predicted. This suggests that the described LES-FGM framework is able to predict the onset of thermoacoustic instabilities and their qualitative changes with addition of hydrogen. © 2023 The Combustion InstituteAssessment of the LES-FGM framework for capturing stable and unstable modes in a hydrogen / methane fuelled premixed combustoracceptedVersio
Nafion/lead oxide-manganese oxide combined catalyst for use as a highly efficient alkaline air electrode in zinc-air battery
No full textIn this study, we report the application of an inexpensive and easily prepared lead oxide-manganese oxide catalyst combined with Nation (designated as Nf/PbMnO(x)) as a highly efficient air-cathode for a zinc-air battery. We verify the mechanistic study of the reduction of O(2) for Nf/PbMnO(x) in alkaline aqueous solution using rotating ring/disk electrode voltammetry, and also an electrochemical approach using a wall-jet screen-printed ring disk electrode. The presence of Nf/PbMnO(x) shows great catalytic activity for the disproportionation reaction of HO(2)(-) to O(2) and OH(-) with an overall 4e(-) reduction of O(2) in the first reduction reaction. The 4e(-) reduction O(2) was eventually achieved at the Nf/PbMnO(x) through evidence from the slope of Koutecky-Levich plots. With these inherent features, we then fabricated the zinc-air battery with the Nf/PbMnO(x) catalyst and examine the performance for a practical application with air cathodes. (C) 2011 Elsevier Ltd. All rights reserved
Vliv pravidelného tréninku na tělesné složení mladých lyžařů běžců ve vztahu k motorické výkonnosti v porovnání s normální populací Effect of regular training on body composition and physical performance in young cross-country skiers: As compared with normal controls
No full textCílem této studie bylo určit tělesné složení a úroveň motorické výkonnosti a zároveň posoudit změny v komponentách tělesného složení a v úrovni motorické výkonnosti v závislosti na pravidelném tréninkovém zatížení aplikovaném v rámci šestiměsíčního tréninkového programu přípravném období, tzv. "suché přípravy", ročního tréninkového cyklu 2003/2004 u skupiny mladých lyžařů běžců, žáků sportovních tříd při ZŠ T. G. Masaryka ve Vimperku a členů lyžařských oddílů Ski-klub Šumava, Libín Prachatice a Sokol Stachy ve věku 12–15 let (n = 81), v porovnání s normální populací (n = 49). Byla provedena dvě měření tělesného složení a motorické výkonnosti, na začátku a konci přípravného období (duben a říjen), tedy podruhé po šestiměsíčním tréninkovém programu. Metodou pro stanovení tělesného složení byla multifrekvenční bioimpedanční analýza (BIA), zařízení B. I. A. 2000-M, Data Input, Germany měřící celkovou impedanci při použití proměnlivé frekvence. Úroveň motorické výkonnosti byla posuzována na základě výsledků základních motorických testů. Z výsledků vyplývá, že systematický trénink realizovaný v prostředí sportovních tříd má evidentně pozitivní dopad, a to nejen v systému přípravy dětí a mládeže pro vrcholový sport, ale především z hlediska vlivu pravidelného pohybového zatížení aplikovaného nad rámec školních osnov na tělesné složení a motorickou výkonnost dospívajícího organismu. Pravidelný trénink tak může z hlediska tělesného složení působit také jako prevence vzniku nadváhy, případně obezity a s tím souvisejících dalších zdravotních rizik v dospělosti. Výsledky této studie mohou být především hodnotnou zpětnou vazbou vedoucí ke zkvalitnění tréninkové přípravy sledovaných jedinců a k obohacení programu lyžařských sportovních tříd obecně. Stejně tak mohou přispět k řešení problematiky reakce dětského a dospívajícího organismu na speciální a specifickou tréninkovou zátěž z hlediska změn tělesného složení, resp. distribuce tělesných tekutin a změn ve struktuře svalové hmoty, a z hlediska změn fyziologického profilu. Studie je součástí dlouhodobého sledování mladých lyžařů běžců v Laboratoři sportovní motoriky FTVS UK v Praze. The aim of this study was to determine body composition parameters and level of physical performance together with evaluation of changes in body composition and in the level of physical performance under the influence of regular training performed during a preparatory training period in a group of young cross-country skiers (both genders), pupils of sport primary school, and the participants of ski-clubs between the ages of 12–15 years (n = 81), as compared with normal controls (n = 49). The multi-frequency BIA method (B. I. A. 2000M, Data Input, Germany) was used for determination of body composition. The level of physical performance was estimated through basic motor tests. Results from the present study indicate the positive effect of systematic regular training performed through the special cross-country skiing sport primary school. Firstly for cultivation of young elite cross-country skiers, resp. sport talents for high performance, and secondly as a factor influencing the body composition and the level of physical performance in children and youth with regular physical activity via ultra physical education lessons. Regular cross-country skiing training seems to be favorably influenced by BC related to physical performance in children and youth. Hence, regular training functions also as a means of prevention of overweight or obesity-affected health and psychological, social, economic and other complications in youth, as in those of adult age. The results from this study can provide valuable feedback affecting the improving of training preparation of the followed subjects as well as the enriching of the sport primary school programme in general. In addition, it can be used to observe how childrens’ bodies respond to special and specific training stimuli in relation to changes in body composition, let us say in the distribution of body liquid and changes in muscle mass as well as in connection with the differences of physiological profile. This study is a part of the longitudinal study of young cross-country skiers in the Sport Research Centre, the Faculty of Physical Education and Sport, Charles University in Prague
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