Search results

1

Heavy metal accumulation in two peat bogs from southern Poland

100%

Fiałkiewicz-Kozieł B., Smieja-Król B., Palowski B., Fiałkiewicz-Kozieł B., Smieja-Król B., Palowski B.

Studia Quaternaria

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2011

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vol. 28

2

Relationship Between Motor Variability, Accuracy, and Ball Speed in the Tennis Serve

100%

Antúnez R., Hernández F., García J., Vaíllo R., Arroyo J.

Journal of Human Kinetics

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2012

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vol. 33

45-53

EN

The main objective of this study was to analyze the motor variability in the performance of the tennis serve and its relationship to performance outcome. Seventeen male tennis players took part in the research, and they performed 20 serves. Linear and non-linear variability during the hand movement was measured by 3D Motion Tracking. Ball speed was recorded with a sports radar gun and the ball bounces were video recorded to calculate accuracy. The results showed a relationship between the amount of variability and its non-linear structure found in performance of movement and the outcome of the serve. The study also found that movement predictability correlates with performance. An increase in the amount of movement variability could affect the tennis serve performance in a negative way by reducing speed and accuracy of the ball.

3

Uwagi o zmienności suewitów

100%

Kosina R.

Acta Societatis Metheoriticae Polonorum

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2017

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vol. 8

84-99

EN

Suevite is the impact breccia rock with glass particles that attracts the attention of researches because of its broad variability. Many characteristics of the environment and impact process determine this attention, and, in consequence, various descriptions and names of the rock are presented in the literature. The Rochechouart impact structure is a good example of suevite or suevite-like rock diversity in its several localities (Rochechouart, Chassenon, LaValette, Montoume). The relationships between suevite components and target rocks can be exemplified by Kara and Popigai and other astroblemes. To simplify the classification of the rock, its main and more stable components (matrix, glass, clasts) should be considered. More detailed analysis of the suevite components can be used for sub-classifications, similarly as it is done for other Earth rocks. In addition, a short description of suevites from various astroblemes is presented. The possibility of the monomict suevite breccia creation is discussed.

4

Effects of Unstable Conditions on Kinematics and Performance Variables in Young Handball Players

100%

Urbán T., Gutiérrez Ó., Moreno F. J.

Journal of Human Kinetics

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2015

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vol. 46

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issue 1

39-48

EN

The execution variability and outcomes found in throwing actions have received special attention in numerous studies in recent years. The aim of this study was to analyze the effect of an unstable condition on velocity, accuracy and kinematics of movement in the seven metres throw in handball. Twenty-five young handball players took part in an experiment, throwing towards a target on a stable and an unstable surface. Each participant performed 32 throws, 16 for each situation. Linear variability of the dominant hand was assessed by 3D Motion Tracking. A radar sports gun was used to record the velocity of the ball and the throws were video recorded to establish their accuracy. Results showed significant decreases in throwing velocity in unstable conditions, but these did not significantly affect the accuracy achieved in performance. Differences were also found in movement kinematics between the two throwing conditions and relationships were found between kinematics, velocity and accuracy.

5

Movements that are both variable and optimal

88%

Latash M. L.

Journal of Human Kinetics

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2012

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vol. 34

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issue 1

5-13

EN

This brief review addresses two major aspects of the neural control of multi-element systems. First, the principle of abundance suggests that the central nervous system unites elements into synergies (co-variation of elemental variables across trials quantified within the framework of the uncontrolled manifold hypothesis) that stabilize important performance variables. Second, a novel method, analytical inverse optimization, has been introduced to compute cost functions that define averaged across trials involvement of individual elements over a range of values of task-specific performance variables. The two aspects reflect two features of motor coordination: (1) using variable solutions that allow performing secondary tasks and stabilizing performance variables; and (2) selecting combinations of elemental variables that follow an optimization principle. We suggest that the conflict between the two approaches (a single solution vs. families of solutions) is apparent, not real. Natural motor variability may be due to using the same cost function across slightly different initial states; on the other hand, there may be variability in the cost function itself leading to variable solutions that are all optimal with respect to slightly different cost functions. The analysis of motor synergies has revealed specific changes associated with atypical development, healthy aging, neurological disorders, and practice. These have allowed formulating hypotheses on the neurophysiological mechanisms involved in the synergic control of actions.

6

Shale gas deposit model and preliminary resources estimation based on mud logging data on gas content variation

88%

Nieć M., Musiał A., Auguścik J., Nieć M., Musiał A., Auguścik J.

Gospodarka Surowcami Mineralnymi

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2019

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vol. 35

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issue 4

7

Scoring Abilities in the Game of Tennis – A Pragmatic Study of Unique Cases

75%

Nowak M., Panfil R.

Human Movement

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2012

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vol. 13

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issue 4

313-322

EN

Purpose. Many studies analyzing the game of tennis overlook assessing such variables as the pure ability to play the game or the skill needed to take an opponent by surprise. This can be quantified in terms of a player’s shot flexibility, variability, velocity, or by the conscious or intuitive adaptability one can possess towards anticipating return shots, how best to hit the ball in order to keep it in play, as well as the buildup of delivering a shot or in scoring a point. The aim of the study was to identify the ability to score points in tennis based on an original set of assessment criteria that were used to measure the different effective plays against an opponent. This included measuring the variability, spatial flexibility and variability of shots taken, as well as the willingness to make risky plays. Methods. The study analyzed the match play of two elite tennis players, Roger Federer and Novak Djokovic, who competed against one another in the final of the 2007 US Open and the semi-final of 2008 Australian Open. Video recording of the two games was used to score and measure the proposed criteria. Results. The study found numerous quantitative and qualitative aspects that could assess the performance of the players. This included measuring the variety, spatial flexibility and variability of shots taken, as well as the willingness to make risky plays. Shot variety, flexibility and variability, as well as the amount of risk taken during game play, were quantifiable in nature. Taking into account the high sporting level of the players, the obtained results are undoubtedly of considerable educational value. Conclusion. The results allow for the conclusion that the teaching process in tennis demands the introduction of significant modifications aimed at the rationalization of technique and the introduction of criteria that can measure player effectiveness.

8

Initial Assessment of Variability in the Modes of Occurrence of Some Trace Elements in Coal Seams with Vertical Profiles in the Upper Silesian Coal Basin in Poland

75%

Parzentny H. R., Róg L., Parzentny H. R., Róg L.

Archives of Mining Sciences

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2020

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vol. 65

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issue 4

9

Effect of siltuximab, omalizumab, infliximab, pembrolizumab and vedolizumab on selected haematological and biochemical parameters in a pig model

75%

Grabowski T., Burmańczuk A., Miazek A., Grabowski T., Burmańczuk A., Miazek A.

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10

Variability of statistical parameters of resistance for reinforced concrete columns with circular cross-section

75%

Lutomirski T. A., Lutomirska M., Lutomirski T. A., Lutomirska M.

Archives of Civil Engineering

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2021

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vol. 67

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issue 2

Refine search results

Heavy metal accumulation in two peat bogs from southern Poland

Relationship Between Motor Variability, Accuracy, and Ball Speed in the Tennis Serve

Uwagi o zmienności suewitów

Effects of Unstable Conditions on Kinematics and Performance Variables in Young Handball Players

Movements that are both variable and optimal

Shale gas deposit model and preliminary resources estimation based on mud logging data on gas content variation

Scoring Abilities in the Game of Tennis – A Pragmatic Study of Unique Cases

Initial Assessment of Variability in the Modes of Occurrence of Some Trace Elements in Coal Seams with Vertical Profiles in the Upper Silesian Coal Basin in Poland

Effect of siltuximab, omalizumab, infliximab, pembrolizumab and vedolizumab on selected haematological and biochemical parameters in a pig model

Variability of statistical parameters of resistance for reinforced concrete columns with circular cross-section