Comparative analysis of the technical and tactical activities of the best table tennis players in the world

У истраживању, које је имало карактер опсервационе, експлоративне еx post facto студије, испитивана је структура простора у којем се манифестује техничко- тактичка активност врхунских играча стоног тениса (играчи н=77; игралице н=77), учесника завршног олимпијског турнира, на одиграним мечевима (играчи н=154; игралице н=154), односно на 820 одиграних сетова (играчи н=423; игралице н=397). Сваки од играча је био описан преко 9 варијабли, а техничко-тактичка активност у мечевима и сетовима била је описана преко 17 варијабли. За основне циљеве студије постављено је утврђивање и поређење структура простора техничко-тактичких активности играча и дефинисање изабраних релевантних моделских карактеристика најбољих такмичара и такмичарки света. Добијени резултати дозвољавају да се закључи како се на основу техничко-тактичке активности врхунских играча и играчица стоног тениса у условима такмичења са равноправним противницима, обезбеђује валидан увид у структуру базичног техничко- тактичког простора, којег описују 9 интерпретабилних латентних димнзија. Структуре простора у популацијама мушкараца и жена се квалитативно нису разликовале. Испитивање утицаја избора доминантне руке на ефикасност извођења техничко- тактичких елемената и успешност, указује на значајне предности леворуких, како играча, тако и играчица. Повезаност показатеља морфолошког статуса са варијаблама техничко-тактичке активност играча и играчица, указала је на високо значајне везе, како у мушкој тако и у женској популацији. Униваријатним и мултиваријатним анализама утврђене су значајне разлике између играча и играчица у квантитативним показатељима техничко-тактичке активности. Резултати указују на суштинске разлике између игара мушкараца и жена у агресивнијој игри у нападу и већој ефикасности постизања поена трећом лоптицом код играча у односу на играчице, док све остале квантитативне разлике у униваријатним анализама представљају последицу ове две значајне разлике. Помоћу бинарне логистичке регресионе анализе формирана су четири предикциона модела за предвиђање исхода сета и меча на основу праћених показатеља техничко тактичке активности у популацији играча и популацији играчица, који су приказали изузетно квалитетне метријске карактеристике.In the study, having the character of observational, exploratory ex post facto study, was examined the structure of space that manifests technical and tactical activities of top table tennis players (men n = 77; women n = 77), participants in the final Olympic tournament, at the final matches (men n = 154; women n = 154), i.e. 820 sets (men n = 423; women n = 397). Each of the players has been described through 9 variables, and technical and tactical activity in matches and sets was described through 17 variables. It was defined for the basic aims of the study to determine and to compare the space structure of technical and tactical activities of the players and defining of the selected relevant model characteristic of top male and female competitors of the world. The obtained results allow one to conclude that on the basis of technical and tactical activities of top male and female table tennis players in terms of competition with equal opponents, provides valid insight into the structure of the basic technical and tactical space described through 9 interpretable latent dimensions. The space structures in men and women populations did not differ qualitatively. Assaying the selection of the dominant hand on the efficiency of performing technical and tactical elements and performance effect points to the significant benefits of left-handed male as well as female players. The connection of the morphological status indicator with technical and tactical activity variables of male and female players, pointed to the highly significant relationship both in men and in women population. Univariate and multivariate analyses revealed significant differences between male and female players in the quantitative indicators of technical and tactical activities. Results indicate fundamental differences between the way how the men and women compete in the more aggressive play, in attack and greater efficiency in achieving point by third ball of male in relation to the female players, while all the other quantitative differences in univariate analysis represent the consequence of these two significant differences. Using binary logistic regression analysis four predictive models were formed for predicting the outcome of the set and match on the basis of monitored indicators of technical and tactical activities in the male and female population of the players showing exceptional metric characteristics quality

Development of new material for the environmental-friendly energy generation processes

The aim of this study was to develop a new material which has high hydrogen storage capacity and hydrogen absorption/desorption rate. This material, which is based on cobalt powder onto which palladium was chemically deposited can be used in environmentally friendly energy generation processes, thus ensuring preventive protection of human health. Hydrogen absorption was investigated using differential scanning calorimetry (DSC) and by measuring hydrogen pressure under isothermal and non-isothermal conditions in a chamber containing either pure cobalt powder either cobalt powder onto which palladium was chemically deposited (Co-0.003 Pd). The mechanism of hydrogen absorption has been described. It was noticed that palladium catalyses hydrogen absorption by dissociating the adsorbed H2 molecules into H atoms more rapidly on its own atoms than on cobalt ones. The catalysis of dissociation of H2 molecules enabled hydrogen absorption into Co-0.003 Pd powder to occur at lower temperatures. The results of this study enable integration of technological and public health investigation in order to ensure preventive protection of human health through enviromental protection

Antifungal activities of basil (Ocimum basilicum L.) extract on Fusarium species

The basil extract composition was determined by the GC-MS method and 38 different components were identified. The major components of the basil extract were estragol (86.72%), trans-α-bergamotene (2.91%), eucalyptol (2.67%), trans-ocimene (1.04%), linalool (0.72%), methyl-eugenol (0.71%), etc. The antifungal potential of the basil extract was tested against Fusarium oxysporum, F. proliferatum, F. subglutinans, and F. verticillioides isolated from cakes, using the agar plate method. Extract concentrations of 0.35 and 0.70% (v/v) significantly inhibited the growth of F. proliferatum (33.37 and 44.30%, respectively) and F. subglutinans (24.74 and 29.27%, respectively) whereas other investigated Fusarium species exhibited much lower sensitivity. The basil extract completely inhibited the growth of investigated Fusarium spp. at the concentration of 1.50% (v/v). Higher concentrations (0.35 and 0.70% (v/v)) reduced growth of aerial mycelium in all tested species. Strong medium pigmentation in the case of F. proliferatum and F. verticillioides was observed. The microscopic examination of the samples confirmed the presence of hyphae deformations with a frequent occurrence of fragmentations, thickenings and diminished sporulation. In addition to the basic, sensory, role the extract of basil has in the food product, it exerted significant antifungal properties, depending on its concentration.Key words: Basil (Ocimum basilicum L.) extract, components, antifungal activity, Fusarium spp

The Phase Diagram of Compact QED Coupled to a Four-Fermi Interaction

Compact lattice Quantum Electrodynamics (QED) with four species of fermions is simulated with massless quarks by using the $\chi$QED scheme of adding a four-fermi interaction to the action. Simulations directly in the chiral limit of massless quarks are done with high statistics on $8^4$, and $16^4$ lattices, and the phase diagram, parameterized by the gauge and the four-fermi couplings, is mapped out. The line of monopole condensation transitions is separate from the line of chiral symmetry restoration. The simulation results indicate that the monopole condensation transition is first order while the chiral transition is second order. The challenges in determining the Universality class of the chiral transition are discussed. If the scaling region for the chiral transition is sufficiently wide, the $16^4$ simulations predict critical indices far from mean field values. We discuss a speculative scenario in which anti-screening provided by double-helix strands of monopole and anti-monopole loops are the agent that balances the screening of fermion anti-fermion pairs to produce an ultra-violet fixed point in the electric coupling.Comment: 29 pages, 8 figures and 2 table

Chiral transition and monopole percolation in lattice scalar QED with quenched fermions

We study the interplay between topological observables and chiral and Higgs transitions in lattice scalar QED with quenched fermions. Emphasis is put on the chiral transition line and magnetic monopole percolation at strong gauge coupling. We confirm that at infinite gauge coupling the chiral transition is described by mean field exponents. We find a rich and complicated behaviour at the endpoint of the Higgs transition line which hampers a satisfactory analysis of the chiral transition. We study in detail an intermediate coupling, where the data are consistent both with a trivial chiral transition clearly separated from monopole percolation and with a chiral transition coincident with monopole percolation, and characterized by the same critical exponent $\nu \simeq 0.65$. We discuss the relevance (or lack thereof) of these quenched results to our understanding of the \chupiv\ model. We comment on the interplay of magnetic monopoles and fermion dynamics in more general contexts.Comment: 29 pages, 13 figures included, LaTeX2e (elsart

Mean field exponents and small quark masses

We demonstrate that the restoration of chiral symmetry at finite-T in a class of confining Dyson-Schwinger equation (DSE) models of QCD is a mean field transition, and that an accurate determination of the critical exponents using the chiral and thermal susceptibilities requires very small values of the current-quark mass: log_{10}(m/m_u) < -5. Other classes of DSE models characterised by qualitatively different interactions also exhibit a mean field transition. Incipient in this observation is the suggestion that mean field exponents are a result of the gap equation's fermion substructure and not of the interaction.Comment: 13 pages, 3 figures, REVTEX, epsfi

Phenomenological interaction between current quarks

We construct a phenomenological model which describes the dynamical chiral symmetry breaking (DCSB) of QCD vacuum and reproduces meson spectra. Quark condensates, the pion decay constant, and meson spectra are well reproduced by phenomenological interaction which consists of a linear confining potential, a Coulombic potential, and the 't Hooft determinant interaction. In this model, the 't Hooft determinant interaction plays a important role not to only \eta,\eta' mass difference, but other meson masses through DCSB.Comment: 18 pages, LaTe

Monopole Percolation in pure gauge compact QED

The role of monopoles in quenched compact QED has been studied by measuring the cluster susceptibility and the order parameter $n_{max}/n_{tot}$ previously introduced by Hands and Wensley in the study of the percolation transition observed in non-compact QED. A correlation between these parameters and the energy (action) at the phase transition has been observed. We conclude that the order parameter $n_{max}/n_{tot}$ is a sensitive probe for studying the phase transition of pure gauge compact QED.Comment: LaTeX file + 4 PS figures, 12 pag., Pre-UAB-FT-308 ILL-(TH)-94-1

Hot Nucleons in Chiral Soliton Models

Chiral lagrangians as effective field theories of QCD are most suitable for the study of nucleons in a hot pion gas because they contain pions and also baryons as solitons of the same action. The semiclassical treatment of the soliton solutions must be augmented by pionic fluctuations which requires renormalisation to 1-loop, and finite temperatures do not introduce new ultraviolet divergencies and may easily be considered. Alternatively, a renormalisation scheme based on the renormalisation group equation at finite temperature comprises and extends the rigorous results of chiral perturbation theory and renders the low energy constants temperature-dependent which allows the construction of temperature-dependent solitons below the critical temperature. The temperature-dependence of the baryon energy and the pion-nucleon coupling is studied. There is no simple scaling law for the temperature-dependence of these quantities.Comment: 17 pages (RevTeX), 5 figure

Monopole Percolation in the Compact Abelian Higgs Model

We have studied the monopole-percolation phenomenon in the four dimensional Abelian theory that contains compact U(1) gauge fields coupled to unitary norm Higgs fields. We have determined the location of the percolation transition line in the plane $(\beta_g, \beta_H)$. This line overlaps the confined-Coulomb and the confined-Higgs phase transition lines, originated by a monopole-condensation mechanism, but continues away from the end-point where this phase transition line stops. In addition, we have determined the critical exponents of the monopole percolation transition away from the phase transition lines. We have performed the finite size scaling in terms of the monopole density instead of the coupling, because the density seems to be the natural parameter when dealing with percolation phenomena.Comment: 13 pages. REVTeX. 16 figs. included using eps