WorldWideScience

Sample records for pirnas ping-pong players

  1. Arbovirus-derived piRNAs exhibit a ping-pong signature in mosquito cells.

    Directory of Open Access Journals (Sweden)

    Nicolas Vodovar

    Full Text Available The siRNA pathway is an essential antiviral mechanism in insects. Whether other RNA interference pathways are involved in antiviral defense remains unclear. Here, we report in cells derived from the two main vectors for arboviruses, Aedes albopictus and Aedes aegypti, the production of viral small RNAs that exhibit the hallmarks of ping-pong derived piwi-associated RNAs (piRNAs after infection with positive or negative sense RNA viruses. Furthermore, these cells produce endogenous piRNAs that mapped to transposable elements. Our results show that these mosquito cells can initiate de novo piRNA production and recapitulate the ping-pong dependent piRNA pathway upon viral infection. The mechanism of viral-piRNA production is discussed.

  2. piRNA biogenesis during adult spermatogenesis in mice is independent of the ping-pong mechanism

    Institute of Scientific and Technical Information of China (English)

    Ergin Beyret; Na Liu; Haifan Lin

    2012-01-01

    piRNAs,a class of small non-coding RNAs associated with PIWI proteins,have broad functions in germline development,transposon silencing,and epigenetic regulation.In diverse organisms,a subset of piRNAs derived from repeat sequences are produced via the interplay between two PIWI proteins.This mechanism,termed "ping-pong"cycle,operates among the PIWI proteins of the primordial mouse testis; however,its involvement in postnatal testes remains elusive.Here we show that adult testicular piRNAs are produced independent of the ping-pong mechanism.We identified and characterized large populations of piRNAs in the adult and postnatal developing testes associated with MILI and MIWI,the only PIWI proteins detectable in these testes.No interaction between MILI and MIWI or sequence feature for the ping-pong mechanism among their piRNAs was detected in the adult testis.The majority of MILI-and MIWI-associated piRNAs originate from the same DNA strands within the same loci.Both populations of piRNAs are biased for 5′ Uracil but not for Adenine on the 10th nucleotide position,and display no complementarity.Furthermore,in Miwi mutants,MILI-associated piRNAs are not downregulated,but instead upregulated.These results indicate that the adult testicular piRNAs are predominantly,if not exclusively,produced by a primary processing mechanism instead of the ping-pong mechanism.In this primary pathway,biogenesis of MILI-and MIWI-associated piRNAs may compete for the same precursors; the types of piRNAs produced tend to be non-selectively dictated by the available precursors in the cell; and precursors with introns tend to be spliced before processed into piRNAs.

  3. Stroke Motion Learning for a Humanoid Robotic Ping-Pong Player Using a Novel Motion Capture System

    Directory of Open Access Journals (Sweden)

    C. H. Lai

    2010-01-01

    Full Text Available Problem statement: Human ping-pong players determine the stroke trajectory according to their experience before the ball enters their court. However, to enable a humanoid robot to select the appropriate stroke motion based on skills learned from 3D motion, important patterns must be generated to simplify the complex 3D motion. Approach: This study developed an effective strategy for teaching ping-pong skills to a humanoid robot. An optical/inertial motion-capture system that retrieves the stroke motion was constructed, along with the retrieved stroke motion trajectories analyzed to obtain the desired stroke patterns of the robot. Results: A motion capture system was implemented mainly to orient the robot on the stroke motion trajectory. This system was applied directly to a ping-pong game between a human player and a pitching machine to enable the robot to learn backhand strokes through human demonstration. The ball was continuously struck to the opponent so that it hit the anticipated region on the opposite side of the court while the pitching machine served the ball. The data were then classified using the proposed stopping detector and then processed by Principal Components Analysis (PCA to generate the stroke patterns after collecting 50 datasets for stroke trajectories. Conclusion: The right arm of the humanoid robot was successfully instructed to perform the actual ping-pong stroke using the generated trajectory.

  4. Histone-derived piRNA biogenesis depends on the ping-pong partners Piwi5 and Ago3 in Aedes aegypti.

    Science.gov (United States)

    Girardi, Erika; Miesen, Pascal; Pennings, Bas; Frangeul, Lionel; Saleh, Maria-Carla; van Rij, Ronald P

    2017-01-23

    The piRNA pathway is of key importance in controlling transposable elements in most animal species. In the vector mosquito Aedes aegypti, the presence of eight PIWI proteins and the accumulation of viral piRNAs upon arbovirus infection suggest additional functions of the piRNA pathway beyond genome defense. To better understand the regulatory potential of this pathway, we analyzed in detail host-derived piRNAs in A. aegypti Aag2 cells. We show that a large repertoire of protein-coding genes and non-retroviral integrated RNA virus elements are processed into genic piRNAs by different combinations of PIWI proteins. Among these, we identify a class of genes that produces piRNAs from coding sequences in an Ago3- and Piwi5-dependent fashion. We demonstrate that the replication-dependent histone gene family is a genic source of ping-pong dependent piRNAs and that histone-derived piRNAs are dynamically expressed throughout the cell cycle, suggesting a role for the piRNA pathway in the regulation of histone gene expression. Moreover, our results establish the Aag2 cell line as an accessible experimental model to study gene-derived piRNAs.

  5. My Ping-Pong Family

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    WHEN I was born, my father was 40 and my mother was 36. Father is a man of few words and an introverted nature. He belongs to that type of people who are very tough and strong-willed; he has worked hard all his life. Mother, on the other hand, is extroverted and eager to excel. My personality is a combination of both of their characters. Father loves playing ping-pong ardently. He used to be a top player of the Henan provincial team and won the men’s singles championship in a contest of five provinces in central and southern China. Mother, a worker at the No. 4 National Textile Mill in Zhengzhou, also loved to play ping-pong when she was young. It was because of the sport that she and Father were brought together and got married. When the Henan

  6. Recursive Ping-Pong Protocols

    DEFF Research Database (Denmark)

    Huttel, Hans; Srba, Jiri

    2004-01-01

    This paper introduces a process calculus with recursion which allows us to express an unbounded number of runs of the ping-pong protocols introduced by Dolev and Yao. We study the decidability issues associated with two common approaches to checking security properties, namely reachability analys...

  7. An Unforgettable Ping Pong Trip

    Institute of Scientific and Technical Information of China (English)

    Melba Rocio

    2009-01-01

    <正>In our memory the famous Ping Pong Diplomacy took place in 1971. At that time the People’s Republic of China and the United States had not yet es- tablished diplomatic relations. In April that year, nine table tennis

  8. Launch Creativity with Ping-Pong Ball Challenge

    Science.gov (United States)

    Kornoelje, Joanne; Roman, Harry T.

    2011-01-01

    Educators at Thomas A. Edison Middle School have worked together to bring invention information and activities to life. One activity in particular, Ping-Pong Ball Invention Challenge, has proven a great success. The Ping-Pong Ball Invention Challenge was inspired by the basic rules for PBS's "Design Squad"'s "Pop Fly" activity. In this article,…

  9. Ping-pong auto-zero amplifier with glitch reduction

    Science.gov (United States)

    Larson, Mark R [Maple Grove, MN

    2008-01-22

    A ping-pong amplifier with reduced glitching is described. The ping-pong amplifier includes a nulling amplifier coupled to a switching network. The switching network is used to auto-zero a ping amplifier within a ping-pong amplifier. The nulling amplifier drives the output of a ping amplifier to a proper output voltage level during auto-zeroing of the ping amplifier. By being at a proper output voltage level, glitches associated with transitioning between a ping amplifier and a pong amplifier are reduced or eliminated.

  10. Meeting Marks Publication of Memoirs on Ping-Pong Diplomacy

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>The year 2011 marked the 40th anniversary of the "Ping-Pong Diplomacy" that was a symbolicturning point in Sino-American relations. The late Chairman Mao Ze-dong, Premier Zhou Enlai and other Chinese

  11. The physics of juggling a spinning ping-pong ball

    Science.gov (United States)

    Widenhorn, Ralf

    2016-12-01

    Juggling a spinning ball with a ping-pong paddle represents a challenge both in terms of hand-eye coordination and physics concepts. Here, we analyze the ping-pong ball's motion, and explore how the correct paddle angle relates to the ball's spin and speed, as it moves vertically up and down. For students, this requires engaging with concepts like momentum, angular momentum, free-body diagrams, and friction. The activities described in this article include high-speed video motion tracking of the ping-pong ball and the investigation of the frictional characteristics of the paddle. They can be done in a physics lab or at home, requiring only inexpensive or commonly used equipment, and can be undertaken by high school or college students.

  12. Spin Rate and Deflection Ratio of a Ping Pong Ball

    Directory of Open Access Journals (Sweden)

    Byung Joon Ahn

    2013-01-01

    Full Text Available To investigate the effects of a spherical object’s spin rate on the curvature of its flight, Ping Pong balls, of varying spin rates, were hit horizontally and recorded from above with a high-speed camera. It was shown that there was a proportional relationship between the ball’s spin rate and deflection ratio. Additionally, using the results of the analyzed data, a coefficient of skin friction of the Ping Pong ball was found to be approximately 0.2 under the specific conditions of this investigation.

  13. Big Hydrophobic Capillary Fluidics; Basically Water Ping Pong in Space

    Science.gov (United States)

    Weislogel, Mark; Attari, Babak; Wollman, Andrew; Cardin, Karl; Geile, John; Lindner, Thomas

    2016-11-01

    Capillary surfaces can be enormous in environments where the effects of gravity are small. In this presentation we review a number of interesting examples from demonstrative experiments performed in drop towers and aboard the International Space Station. The topic then focuses on large length scale hydrophobic phenomena including puddle jumping, spontaneous particle ejections, and large drop rebounds akin to water ping pong in space. Unseen footage of NASA Astronaut Scott Kelly playing water ping pong in space will be shown. Quantitative and qualitative results are offered to assist in the design of experiments for ongoing research. NASA NNX12A047A.

  14. Moment of Inertia of a Ping-Pong Ball

    Science.gov (United States)

    Cao, Xian-Sheng

    2012-01-01

    This note describes how to theoretically calculate and experimentally measure the moment of inertia of a Ping-Pong[R] ball. The theoretical calculation results are in good agreement with the experimental measurements that can be reproduced in an introductory physics laboratory.

  15. Decidability Issues for Extended Ping-Pong Protocols

    DEFF Research Database (Denmark)

    Huttel, Hans; Srba, Jiri

    2006-01-01

    We use some recent techniques from process algebra to draw several conclusions about the well studied class of ping-pong protocols introduced by Dolev and Yao. In particular we show that all nontrivial properties, including reachability and equivalence checking wrt. the whole van Glabbeek's spect...

  16. Production of virus-derived ping-pong-dependent piRNA-like small RNAs in the mosquito soma.

    Directory of Open Access Journals (Sweden)

    Elaine M Morazzani

    2012-01-01

    Full Text Available The natural maintenance cycles of many mosquito-borne pathogens require establishment of persistent non-lethal infections in the invertebrate host. The mechanism by which this occurs is not well understood, but we have previously shown that an antiviral response directed by small interfering RNAs (siRNAs is important in modulating the pathogenesis of alphavirus infections in the mosquito. However, we report here that infection of mosquitoes with an alphavirus also triggers the production of another class of virus-derived small RNAs that exhibit many similarities to ping-pong-dependent piwi-interacting RNAs (piRNAs. However, unlike ping-pong-dependent piRNAs that have been described previously from repetitive elements or piRNA clusters, our work suggests production in the soma. We also present evidence that suggests virus-derived piRNA-like small RNAs are capable of modulating the pathogenesis of alphavirus infections in dicer-2 null mutant mosquito cell lines defective in viral siRNA production. Overall, our results suggest that a non-canonical piRNA pathway is present in the soma of vector mosquitoes and may be acting redundantly to the siRNA pathway to target alphavirus replication.

  17. Ping-Pong Robotics with High-Speed Vision System

    DEFF Research Database (Denmark)

    Li, Hailing; Wu, Haiyan; Lou, Lei

    2012-01-01

    , a multithreshold legmentation algorithm is applied in a stereo-vision running at 150Hz. Based on the estimated 3D ball positions, a novel two-phase trajectory prediction is exploited to determine the hitting position. Benefiting from the high-speed visual feedback, the hitting position and thus the motion planning......The performance of vision-based control is usually limited by the low sampling rate of the visual feedback. We address Ping-Pong robotics as a widely studied example which requires high-speed vision for highly dynamic motion control. In order to detect a flying ball accurately and robustly...

  18. A Flexible Improvement for Ping-Pong Protocol

    Institute of Scientific and Technical Information of China (English)

    LIU Yu; HUA Sha; WANG Xiao-Xin; LI Yue; YE Jun; LI Jun

    2006-01-01

    A deterministic quantum communication protocol, called the ping-pong protocol, has been represented by Bostr(o)m and Felbinger [Phys. Rev. Lett. 89 (2002) 187902]. Based on an entangled pair of photons, it allows asymptotically secure key distribution and quasi-secure direct communication. However, it was concluded from our previous research that the experiment realization of this protocol requires two optic paths strictly equivalent for interferometry. Here we propose an improved protocol, which is more flexible and secure for conceivable applications. Its feasibility and security are also discussed.

  19. Ping-Pong Robotics with High-Speed Vision System

    OpenAIRE

    Li, Hailing; Wu, Haiyan; Lou, Lei; Kühnlenz, Kolja; Ravn, Ole

    2012-01-01

    The performance of vision-based control is usually limited by the low sampling rate of the visual feedback. We address Ping-Pong robotics as a widely studied example which requires high-speed vision for highly dynamic motion control. Inorder to detect a flying ball accurately and robustly, a multithreshold legmentation algorithm is applied in a stereo-vision running at 150Hz. Based on the estimated 3D ball positions, a novel two-phase trajectory prediction is exploited to determine the hittin...

  20. Commemorative Activities for 37th Anniversary of Ping Pong Diplomacy Held in The United States

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>At the invitation of the Richard Nixon Library & Birthplace Foundation, CPAFFC Vice President Li Xiaolin led a delegation to attend the China-US Table Tennis Tournament and the Exhibition of Ping Pong Diplomacy jointly sponsored by the

  1. Ping-pong effects study in PIC turbo joint detection for TDD CDMA

    Institute of Scientific and Technical Information of China (English)

    Song Changjian; Zhong Zifa; Zhang Shuo

    2009-01-01

    A kind of turbo joint detection scheme based on parallel interference cancellation (PIC) is studied; then, the eigenvalues of iteration matrix is deeply analyzed for studying the ping-pong effects in PIC JD and the corresponding compensation approach is introduced. Finally, the proposed algorithm is validated through computer simulation in TDD CDMA uplink transmission. The result shows that the ping-pong effects are almost avoided completely in the presence of the compensation scheme, and system performance is greatly improved.

  2. A Robust Vision Module for Humanoid Robotic Ping-Pong Game

    Directory of Open Access Journals (Sweden)

    Xiaopeng Chen

    2015-04-01

    Full Text Available Developing a vision module for a humanoid ping-pong game is challenging due to the spin and the non-linear rebound of the ping-pong ball. In this paper, we present a robust predictive vision module to overcome these problems. The hardware of the vision module is composed of two stereo camera pairs with each pair detecting the 3D positions of the ball on one half of the ping-pong table. The software of the vision module divides the trajectory of the ball into four parts and uses the perceived trajectory in the first part to predict the other parts. In particular, the software of the vision module uses an aerodynamic model to predict the trajectories of the ball in the air and uses a novel non-linear rebound model to predict the change of the ball's motion during rebound. The average prediction error of our vision module at the ball returning point is less than 50 mm - a value small enough for standard sized ping-pong rackets. Its average processing speed is 120fps. The precision and efficiency of our vision module enables two humanoid robots to play ping-pong continuously for more than 200 rounds.

  3. A Robust Vision Module for Humanoid Robotic Ping-Pong Game

    Directory of Open Access Journals (Sweden)

    Xiaopeng Chen

    2015-04-01

    Full Text Available Developing a vision module for a humanoid ping-pong game is challenging due to the spin and the non-linear rebound of the ping-pong ball. In this paper, we present a robust predictive vision module to overcome these problems. The hardware of the vision module is composed of two stereo camera pairs with each pair detecting the 3D positions of the ball on one half of the ping-pong table. The software of the vision module divides the trajectory of the ball into four parts and uses the perceived trajectory in the first part to predict the other parts. In particular, the software of the vision module uses an aerodynamic model to predict the trajectories of the ball in the air and uses a novel non-linear rebound model to predict the change of the ball’s motion during rebound. The average prediction error of our vision module at the ball returning point is less than 50 mm — a value small enough for standard sized ping-pong rackets. Its average processing speed is 120fps. The precision and efficiency of our vision module enables two humanoid robots to play ping-pong continuously for more than 200 rounds.

  4. Eavesdropping on the 'ping-pong' quantum communi0ation protocol freely in a noise channel

    Institute of Scientific and Technical Information of China (English)

    Deng Fu-Guo; Li Xi-Han; Li Chun-Yan; Zhou Ping; Zhou Hong-Yu

    2007-01-01

    We introduce an attack scheme for eavesdropping freely the ping-pong quantum communication protocol proposed by Bostr(o)m and Felbinger [Phys. Rev. Lett. 89, 187902 (2002)] in a noise channel. The vicious eavesdropper, Eve,intercepts and measures the travel photon transmitted between the sender and the receiver. Then she replaces the quantum signal with a multi-photon signal in the same state, and measures the returned photons with the measuring basis, with which Eve prepares the fake signal except for one photon. This attack increases neither the quantum channel losses nor the error rate in the sampling instances for eavesdropping check. It works for eavesdropping the secret message transmitted with the ping-pong protocol. Finally, we propose a way for improving the security of the ping-pong protocol.

  5. Monotonic Set-Extended Prefix Rewriting and Verification of Recursive Ping-Pong Protocols

    DEFF Research Database (Denmark)

    Delzanno, Giorgio; Esparza, Javier; Srba, Jiri

    2006-01-01

    Ping-pong protocols with recursive definitions of agents, but without any active intruder, are a Turing powerful model. We show that under the environment sensitive semantics (i.e. by adding an active intruder capable of storing all exchanged messages including full analysis and synthesis...

  6. Taking a Swat at Physics with a Ping-Pong Paddle.

    Science.gov (United States)

    Graney, Chris M.

    1994-01-01

    A professor of physics discusses ideas on how to use physics to improve your ping-pong game. Describes how basic physics was used to analyze a simple ball-paddle collision problem and provide students with insight on the application of physics to a fun and real life situation. (ZWH)

  7. Comparing the efficiencies of different detect strategies in the ping-pong protocol

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The way to compare the efficiencies of different detect strategies (DSs) in the "ping-pong" protocol is studied. The trade-off between information gain and dis- turbance is calculated and compared for different DSs. The comparison result primely tallies with our intuitional analysis. It is shown that the analysis of this trade-off is a feasible way to compare the performances of different DSs in theory.

  8. A FAST SEAMLESS HANDOVER SCHEME AND ITS CDT OPTIMIZATION FOR PING-PONG TYPE OF MOVEMENT

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In mobile IPv6 networks, the ping-pong type of movement brings about frequent handovers andthus increases signaling burden. This letter proposes a fast seamless handover scheme where the access routerkeeps the mobile node's old reservation till the offline Count Down Timer (CDT) expires in order to reducehandover signaling and delay while the mobile node returns in a very short period of time. Based upon a pois-son mobility model, an simple expression for CDT optimization is given out for the scheme to achieve the bestcost performance of resource reservation.

  9. Ping-Pong Beam Training for Reciprocal Channels with Delay Spread

    DEFF Research Database (Denmark)

    Carvalho, Elisabeth De; Andersen, Jørgen Bach

    2015-01-01

    We present an iterative beam training procedure for a reciprocal channel with delay spread between two massive antenna arrays. The primary application is communication at millimeter wave frequencies. The procedure is based on ping pong transmissions. For each matricial channel coefficient......, it tracks the left and right singular vectors associated to the maximal singular value. Based on the set of singular vectors, we build transmit and receive equalizers. A simple equalization based on matched filtering is showed to be optimal in the case of a Gaussian i.i.d. channel and a sparse channel....

  10. Ping-Pong Beam Training with Hybrid Digital-Analog Antenna Arrays

    DEFF Research Database (Denmark)

    Manchón, Carles Navarro; Carvalho, Elisabeth De; Andersen, Jørgen Bach

    2017-01-01

    In this article we propose an iterative training scheme that approximates optimal beamforming between two transceivers equipped with hybrid digital-analog antenna arrays. Inspired by methods proposed for digital arrays that exploit algebraic power iterations, the proposed training procedure...... is based on a series of alternate (ping-pong) transmissions between the two devices over a reciprocal channel. During the transmissions, the devices updates their digital beamformers by conjugation and normalization operations on the received digital signal, while the analog beamformers are progressively...

  11. Studies on Non-Steady State Enzyme Kinetics of Ping Pong Bi Bi Mechanism%Ping Pong Bi Bi机制的非稳态酶动力学布尔函数图论研究

    Institute of Scientific and Technical Information of China (English)

    赵敏

    2001-01-01

    以非稳态酶动力学的布尔函数图形方法[1],来研究一类Ping Pong Bi Bi机制的非稳态酶动力学问题,推导出此类反应的非稳态酶动力学方程,并对此动力学方程进行了讨论,分析了此类Ping Pong Bi Bi机制酶反应体系的非稳态酶动力学方程.

  12. Arbovirus-derived piRNAs exhibit a ping-pong signature in mosquito cells.

    NARCIS (Netherlands)

    Vodovar, N.; Bronkhorst, A.W.; Cleef, K.W.R. van; Miesen, P.; Blanc, H.; Rij, R.P. van; Saleh, M.C.

    2012-01-01

    The siRNA pathway is an essential antiviral mechanism in insects. Whether other RNA interference pathways are involved in antiviral defense remains unclear. Here, we report in cells derived from the two main vectors for arboviruses, Aedes albopictus and Aedes aegypti, the production of viral small R

  13. Ping-pong gaze” secondary to monoamine oxidase inhibitor overdose

    Directory of Open Access Journals (Sweden)

    Amy Attaway

    2016-01-01

    Full Text Available An infrequent manifestation of monoamine oxidase inhibitor (MAOI toxicity is “ping-pong gaze” (PPG. We describe the case of a 26-year-old female who was found unresponsive after taking 40 tablets of phenelzine. On presentation to the hospital, her eyes were moving in characteristic “ping pong” fashion. After 6 hours her gaze terminated. The following day her neurologic exam was benign and she had no long-term sequelae. While the etiology of PPG is unknown, it is most often seen with irreversible structural brain damage. However, a detailed literature review revealed that previous cases of MAOI toxicity where the patient survived have all had complete neurologic recovery.

  14. Dynamic Inter Arrival Time Based Seamless Handoff for Mobile WIMAX Ping-Pong Calls Bypassing PKMv2 EAP Authentication

    Directory of Open Access Journals (Sweden)

    B.Sridevi

    2012-06-01

    Full Text Available The rapid growth of wireless communication and its persistent use influences all walks of life. Mobile WiMAX IEEE 802.16e standard enabled convergence of mobile and fixed broadband networks through a common wide-area radio-access technology and flexible network architecture. It aims to provide seamless support to its users but an inevitable is that the long delay which occurs during the handoff management in every network process. This paper proposes a Dynamic Interval based Processing Algorithm to separate ping-pong users from the pool of users and to process them separately thus reducing the overhead of network re-entry process. Incoming users are divided into three categories like new user, old user and ping pong user. New user should undergo all the phases of network entry process, old user is provided with authentication key which leads to skipping of steps in generation of keys. Proposed algorithm deals with identifying the ping pong users by calculating the inter arrival duration and rate with same base station. When assured authenticated ping-pong users enter the network next time within the allotted time they will be provided with last used Traffic Encryption Key (TEK thus bypassing key generation phase . It is observed that the proposed work performs the authentication phase and cancels the key generation phase which leads to minimum network entry delay and it saves to the maximum of 80% processing time. The network model was developed using Network Simulator and the algorithm was implemented in MATLAB GUIDE which gets connected to the database developed in MYSQL.This approach is justified through its timing analysis result which proves the efficient swift in the handoff processes.

  15. The eavesdropping information in W\\'{o}jcik's scheme on ping-pong protocol in high lossy quantum channel

    CERN Document Server

    Zhang, Z J

    2004-01-01

    In this paper the relation between the mutual information and the quantum bit error rates (QBERs) is established. A simple strategy to characterize sufficiently the information gain is proposed. Various eavesdropping information and their corresponding possibilities with which the eavesdropper (Eve) gains the eavesdropping information in W\\'{o}jcik's eavesdropping scheme [Phys. Rev. Lett. {\\bf 90}, 157901(2003)] on the ping-pong protocol in a high lossy quantum channel are worked out. In addition, some mistakes in the eavesdropping scheme are pointed out.

  16. The Drosophila HP1 homologue Rhino is required for transposon silencing and piRNA production by dual strand clusters

    Science.gov (United States)

    Klattenhoff, Carla; Xi, Hualin; Li, Chengjian; Lee, Soohyun; Xu, Jia; Khurana, Jaspreet S.; Zhang, Fan; Schultz, Nadine; Koppetsch, Birgit S.; Nowosielska, Anetta; Seitz, Herve; Zamore, Phillip D.; Weng, Zhiping; Theurkauf, William E.

    2009-01-01

    Summary piRNAs silence transposons and maintain genome integrity during germ-line development. In Drosophila, transposon-rich heterochromatic clusters encode piRNAs either on both genomic strands (dual-strand clusters) or predominantly one genomic strand (uni-strand clusters). Primary piRNAs derived from these clusters are proposed to drive a ping-pong amplification cycle catalyzed by proteins that localize to the perinuclear nuage. We show that the HP1 homologue Rhino is required for nuage organization, transposon silencing, and ping-pong amplification of piRNAs. rhi mutations virtually eliminate piRNAs from the dual-strand clusters and block production of putative precursor RNAs from both strands of the major 42AB dual-strand cluster, but do not block production of transcripts or piRNAs from the uni-strand clusters. Furthermore, Rhino protein associates with the 42AB dual-strand cluster, but does not bind to uni-strand cluster 2 or flamenco. Rhino thus appears to promote transcription of dual-strand clusters, leading to production of piRNAs that drive the ping-pong amplification cycle. PMID:19732946

  17. RNA helicase Spn-E is required to maintain Aub and AGO3 protein levels for piRNA silencing in the germline of Drosophila.

    Science.gov (United States)

    Ryazansky, Sergei S; Kotov, Alexei A; Kibanov, Mikhail V; Akulenko, Natalia V; Korbut, Alina P; Lavrov, Sergei A; Gvozdev, Vladimir A; Olenina, Ludmila V

    2016-09-01

    Germline-specific RNA helicase Spindle-E (Spn-E) is known to be essential for piRNA silencing in Drosophila that takes place mainly in the perinuclear nuage granules. Loss-of-function spn-E mutations lead to tandem Stellate genes derepression in the testes and retrotransposon mobilization in the ovaries. However, Spn-E functions in the piRNA pathway are still obscure. Analysis of total library of short RNAs from the testes of spn-E heterozygous flies revealed the presence of abundant piRNA ping-pong pairs originating from Su(Ste) transcripts. The abundance of these ping-pong pairs were sharply reduced in the library from the testes of spn-E mutants. Thus we found that ping-pong mechanism contributed to Su(Ste) piRNA generation in the testes. The lack of Spn-E caused a significant drop of protein levels of key ping-pong participants, Aubergine (Aub) and AGO3 proteins of PIWI subfamily, in the germline of both males and females, but did not disrupt of their assembly in nuage granules. We found that observed decline of the protein expression was not caused by suppression of aub and ago3 transcription as well as total transcription, indicating possible contribution of Spn-E to post-transcriptional regulation.

  18. Noncoding RNA. piRNA-guided transposon cleavage initiates Zucchini-dependent, phased piRNA production.

    Science.gov (United States)

    Han, Bo W; Wang, Wei; Li, Chengjian; Weng, Zhiping; Zamore, Phillip D

    2015-05-15

    PIWI-interacting RNAs (piRNAs) protect the animal germ line by silencing transposons. Primary piRNAs, generated from transcripts of genomic transposon "junkyards" (piRNA clusters), are amplified by the "ping-pong" pathway, yielding secondary piRNAs. We report that secondary piRNAs, bound to the PIWI protein Ago3, can initiate primary piRNA production from cleaved transposon RNAs. The first ~26 nucleotides (nt) of each cleaved RNA becomes a secondary piRNA, but the subsequent ~26 nt become the first in a series of phased primary piRNAs that bind Piwi, allowing piRNAs to spread beyond the site of RNA cleavage. The ping-pong pathway increases only the abundance of piRNAs, whereas production of phased primary piRNAs from cleaved transposon RNAs adds sequence diversity to the piRNA pool, allowing adaptation to changes in transposon sequence. Copyright © 2015, American Association for the Advancement of Science.

  19. The Drosophila HP1 homolog Rhino is required for transposon silencing and piRNA production by dual-strand clusters.

    Science.gov (United States)

    Klattenhoff, Carla; Xi, Hualin; Li, Chengjian; Lee, Soohyun; Xu, Jia; Khurana, Jaspreet S; Zhang, Fan; Schultz, Nadine; Koppetsch, Birgit S; Nowosielska, Anetta; Seitz, Herve; Zamore, Phillip D; Weng, Zhiping; Theurkauf, William E

    2009-09-18

    Piwi-interacting RNAs (piRNAs) silence transposons and maintain genome integrity during germline development. In Drosophila, transposon-rich heterochromatic clusters encode piRNAs either on both genomic strands (dual-strand clusters) or predominantly one genomic strand (uni-strand clusters). Primary piRNAs derived from these clusters are proposed to drive a ping-pong amplification cycle catalyzed by proteins that localize to the perinuclear nuage. We show that the HP1 homolog Rhino is required for nuage organization, transposon silencing, and ping-pong amplification of piRNAs. rhi mutations virtually eliminate piRNAs from the dual-strand clusters and block production of putative precursor RNAs from both strands of the major 42AB dual-strand cluster, but not of transcripts or piRNAs from the uni-strand clusters. Furthermore, Rhino protein associates with the 42AB dual-strand cluster,but does not bind to uni-strand cluster 2 or flamenco. Rhino thus appears to promote transcription of dual-strand clusters, leading to production of piRNAs that drive the ping-pong amplification cycle.

  20. Implementing web-based ping-pong-type e-communication to enhance staff satisfaction, multidisciplinary cooperation, and clinical effectiveness

    Science.gov (United States)

    Yeh, Pei-Han; Hung, Shih-Kai; Lee, Moon-Sing; Chiou, Wen-Yen; Lai, Chun-Liang; Tsai, Wei-Ta; Hsieh, Hui-Ling; Shih, Yi-Ting; Chen, Liang-Cheng; Huang, Li-Wen; Lin, Yi-An; Lin, Po-Hao; Lin, Yung-Hsiang; Liu, Dai-Wei; Hsu, Feng-Chun; Tsai, Shiang-Jiun; Liu, Jia-Chi; Chung, En-Seu; Lin, Hon-Yi

    2016-01-01

    Abstract Background: Frequent multidisciplinary communication is essential in conducting daily radiotherapy (RT) practice. However, traditional oral or paper-based communication has limitations. E-communication has been suggested, but its effects are still not well demarcated in the field of radiation oncology. Objects: In our web-based integrated information platform, we constructed a ping-pong-type e-communication function to transfer specific notations among multidisciplinary RT staffs. The purpose was to test whether applying this e-communication can increase effectiveness of multidisciplinary cooperation when compared with oral or paper-based practice. Staff satisfaction and clinical benefits were also demonstrated. Design and setting: A real-world quality-improving study was conducted in a large center of radiation oncology. Participants and dataset used: Before and after applying multidisciplinary e-communication (from 2014 to 2015), clinical RT staffs were surveyed for their user experience and satisfaction (n = 23). For measuring clinical effectiveness, a secondary database of irradiated head and neck cancer patients was re-analyzed for comparing RT toxicities (n = 402). Interventions: Applying ping-pong-type multidisciplinary reflective e-communication was the main intervention. Outcome measures: For measuring staff satisfaction, eight domains were surveyed, such as timeliness, convenience, and completeness. For measuring clinical effectiveness of multidisciplinary cooperation, event rates of severe (i.e., grade 3–4) RT mucositis and dermatitis were recorded. Results: Overall, when compared with oral communication only, e-communication demonstrated multiple benefits, particularly on notation-review convenience (2.00 ± 1.76 vs 9.19 ± 0.81; P communication showed statistically significant benefits on all eight domains, especially on notation-review convenience (5.05 ± 2.11 vs 9.19 ± 0.81; P communication (8.76 ± 0

  1. The Ping Pong Pendulum

    CERN Document Server

    Lynch, Peter

    2015-01-01

    Many damped mechanical systems oscillate with increasing frequency as the amplitude decreases. One popular example is Euler's Disk, where the point of contact rotates with increasing rapidity as the energy is dissipated. We study a simple mechanical pendulum that exhibits this behaviour.

  2. Distinct sets of PIWI proteins produce arbovirus and transposon-derived piRNAs in Aedes aegypti mosquito cells.

    Science.gov (United States)

    Miesen, Pascal; Girardi, Erika; van Rij, Ronald P

    2015-07-27

    The PIWI-interacting RNA (piRNA) pathway is essential for transposon silencing in many model organisms. Its remarkable efficiency relies on a sophisticated amplification mechanism known as the ping-pong loop. In Alphavirus-infected Aedes mosquitoes, piRNAs with sequence features that suggest ping-pong-dependent biogenesis are produced from viral RNA. The PIWI family in Aedes mosquitoes is expanded when compared to other model organisms, raising the possibility that individual PIWI proteins have functionally diversified in these insects. Here, we show that Piwi5 and Ago3, but none of the other PIWI family members, are essential for piRNA biogenesis from Sindbis virus RNA in infected Aedes aegypti cells. In contrast, the production of piRNAs from transposons relies on a more versatile set of PIWI proteins, some of which do not contribute to viral piRNA biogenesis. These results indicate that functional specialization allows distinct mosquito PIWI proteins to process RNA from different endogenous and exogenous sources.

  3. Distinct sets of PIWI proteins produce arbovirus and transposon-derived piRNAs in Aedes aegypti mosquito cells

    Science.gov (United States)

    Miesen, Pascal; Girardi, Erika; van Rij, Ronald P.

    2015-01-01

    The PIWI-interacting RNA (piRNA) pathway is essential for transposon silencing in many model organisms. Its remarkable efficiency relies on a sophisticated amplification mechanism known as the ping-pong loop. In Alphavirus-infected Aedes mosquitoes, piRNAs with sequence features that suggest ping-pong-dependent biogenesis are produced from viral RNA. The PIWI family in Aedes mosquitoes is expanded when compared to other model organisms, raising the possibility that individual PIWI proteins have functionally diversified in these insects. Here, we show that Piwi5 and Ago3, but none of the other PIWI family members, are essential for piRNA biogenesis from Sindbis virus RNA in infected Aedes aegypti cells. In contrast, the production of piRNAs from transposons relies on a more versatile set of PIWI proteins, some of which do not contribute to viral piRNA biogenesis. These results indicate that functional specialization allows distinct mosquito PIWI proteins to process RNA from different endogenous and exogenous sources. PMID:26068474

  4. piRNAs from Pig Testis Provide Evidence for a Conserved Role of the Piwi Pathway in Post-Transcriptional Gene Regulation in Mammals.

    Science.gov (United States)

    Gebert, Daniel; Ketting, René F; Zischler, Hans; Rosenkranz, David

    2015-01-01

    Piwi-interacting (pi-) RNAs guide germline-expressed Piwi proteins in order to suppress the activity of transposable elements (TEs). But notably, the majority of pachytene piRNAs in mammalian testes is not related to TEs. This raises the question of whether the Piwi/piRNA pathway exerts functions beyond TE silencing. Although gene-derived piRNAs were described many times, a possible gene-regulatory function was doubted due to the absence of antisense piRNAs. Here we sequenced and analyzed piRNAs expressed in the adult testis of the pig, as this taxon possesses the full set of mammalian Piwi paralogs while their spermatozoa are marked by an extreme fitness due to selective breeding. We provide an exhaustive characterization of porcine piRNAs and genomic piRNA clusters. Moreover, we reveal that both sense and antisense piRNAs derive from protein-coding genes, while exhibiting features that clearly show that they originate from the Piwi/piRNA-mediated post-transcriptional silencing pathway, commonly referred to as ping-pong cycle. We further show that the majority of identified piRNA clusters in the porcine genome spans exonic sequences of protein-coding genes or pseudogenes, which reveals a mechanism by which primary antisense piRNAs directed against mRNA can be generated. Our data provide evidence that spliced mRNAs, derived from such loci, are not only targeted by piRNAs but are also subject to ping-pong cycle processing. Finally, we demonstrate that homologous genes are targeted and processed by piRNAs in pig, mouse and human. Altogether, this strongly suggests a conserved role for the mammalian Piwi/piRNA pathway in post-transcriptional regulation of protein-coding genes, which did not receive much attention so far.

  5. Nernst-ping-pong model for evaluating the effects of the substrate concentration and anode potential on the kinetic characteristics of bioanode.

    Science.gov (United States)

    Peng, Sikan; Liang, Da-Wei; Diao, Peng; Liu, Yanyan; Lan, Fei; Yang, Yuhan; Lu, Shanfu; Xiang, Yan

    2013-05-01

    Understanding the electron-transfer mechanism and kinetic characteristics of bioanodes is greatly significant to enhance the electron-generating efficiencies in bioelectrochemical systems (BESs). A Nernst-ping-pong model is proposed here to investigate the kinetics and biochemical processes of bioanodes in a microbial electrolysis cell. This model can accurately describe the effects of the substrate (including substrate inhibition) and the anode potential on the current of bioanodes. Results show that the half-wave potential positively shifts as the substrate concentration increases, indicating that the rate-determining steps of anodic processes change from substrate oxidation to intracellular electron transport reaction. The anode potential has negligible effects on the enzymatic catalysis of anodic microbes in the range of -0.25 V to +0.1 V vs. a saturated calomel electrode. It turns out that to reduce the anodic energy loss caused by overpotential, higher substrate concentrations are preferred, if the substrate do not significantly and adversely affect the output current. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. 乒乓球与游泳训练儿童的执行功能比较研究%Primary study on executive function in children with Ping-Pong training and swimming training

    Institute of Scientific and Technical Information of China (English)

    张劲松; 季星; 颜崇淮; 徐健; 任芳; 沈理笑

    2009-01-01

    目的 探讨接受不同类型运动训练儿童的执行功能特点.方法 以40名参加乒乓球训练(乒乓球组)和41名参加游泳训练(游泳组)的6~9岁儿童为研究对象,分别完成GO/NOGO任务,采集和分析两组儿童的行为学指标(反应时间和正确率)及事件相关电位成分N2的波幅.结果 与乒乓球组比较,游泳组GO和NOGO的反应时间较快,而正确率较低,差异均有统计学意义(P<0.05和P<0.01).游泳组和乒乓组脑电图CPz点NOGO-N2的波幅分别为(-11.36±9.4)μV和(-7.55±7.99)μV,组间比较差异有统计学意义(P<0.05).结论 接受乒乓球训练的儿童在抑制性控制方面强于接受游泳训练的儿童.%Objective To investigate the executive function of children with different sports training. Methods Forty children with Ping-Pong training (Ping-Pong group) and 41 children with swimming training (swimming group), aged 6-9 years, completed GO/NOGO task. Behavioral data (reaction time and accuracy) and event related potential component N2 were collected and analyzed. Results The reaction time was significantly faster and accuracy significantly lower of GO task and NOGO task in swimming group than in Ping-Pong group (P<0.05 and P<0.01). There were significant differences in the amplitude of NOGO-N2 on site CPz between swimming group and Ping-Pong group[(-11.36±9.4) μV vs (-7.55±7.99) μV, P<0.05]. Conclusion The inhibitory function of children with Ping-Pong training is stronger than those with swimming training.

  7. The structural biochemistry of Zucchini implicates it as a nuclease in piRNA biogenesis.

    Science.gov (United States)

    Ipsaro, Jonathan J; Haase, Astrid D; Knott, Simon R; Joshua-Tor, Leemor; Hannon, Gregory J

    2012-11-08

    PIWI-family proteins and their associated small RNAs (piRNAs) act in an evolutionarily conserved innate immune mechanism to provide essential protection for germ-cell genomes against the activity of mobile genetic elements. piRNA populations comprise a molecular definition of transposons, which permits them to distinguish transposons from host genes and selectively silence them. piRNAs can be generated in two distinct ways, forming either primary or secondary piRNAs. Primary piRNAs come from discrete genomic loci, termed piRNA clusters, and seem to be derived from long, single-stranded precursors. The biogenesis of primary piRNAs involves at least two nucleolytic steps. An unknown enzyme cleaves piRNA cluster transcripts to generate monophosphorylated piRNA 5' ends. piRNA 3' ends are probably formed by exonucleolytic trimming, after a piRNA precursor is loaded into its PIWI partner. Secondary piRNAs arise during the adaptive 'ping-pong' cycle, with their 5' termini being formed by the activity of PIWIs themselves. A number of proteins have been implicated genetically in primary piRNA biogenesis. One of these, Drosophila melanogaster Zucchini, is a member of the phospholipase-D family of phosphodiesterases, which includes both phospholipases and nucleases. Here we produced a dimeric, soluble fragment of the mouse Zucchini homologue (mZuc; also known as PLD6) and show that it possesses single-strand-specific nuclease activity. A crystal structure of mZuc at 1.75 Å resolution indicates greater architectural similarity to phospholipase-D family nucleases than to phospholipases. Together, our data suggest that the Zucchini proteins act in primary piRNA biogenesis as nucleases, perhaps generating the 5' ends of primary piRNAs.

  8. Conserved generation of short products at piRNA loci

    Directory of Open Access Journals (Sweden)

    Khorshid Mohsen

    2011-01-01

    Full Text Available Abstract Background The piRNA pathway operates in animal germ lines to ensure genome integrity through retrotransposon silencing. The Piwi protein-associated small RNAs (piRNAs guide Piwi proteins to retrotransposon transcripts, which are degraded and thereby post-transcriptionally silenced through a ping-pong amplification process. Cleavage of the retrotransposon transcript defines at the same time the 5' end of a secondary piRNA that will in turn guide a Piwi protein to a primary piRNA precursor, thereby amplifying primary piRNAs. Although several studies provided evidence that this mechanism is conserved among metazoa, how the process is initiated and what enzymatic activities are responsible for generating the primary and secondary piRNAs are not entirely clear. Results Here we analyzed small RNAs from three mammalian species, seeking to gain further insight into the mechanisms responsible for the piRNA amplification loop. We found that in all these species piRNA-directed targeting is accompanied by the generation of short sequences that have a very precisely defined length, 19 nucleotides, and a specific spatial relationship with the guide piRNAs. Conclusions This suggests that the processing of the 5' product of piRNA-guided cleavage occurs while the piRNA target is engaged by the Piwi protein. Although they are not stabilized through methylation of their 3' ends, the 19-mers are abundant not only in testes lysates but also in immunoprecipitates of Miwi and Mili proteins. They will enable more accurate identification of piRNA loci in deep sequencing data sets.

  9. MIWI2 and MILI Have Differential Effects on piRNA Biogenesis and DNA Methylation

    Directory of Open Access Journals (Sweden)

    Sergei A. Manakov

    2015-08-01

    Full Text Available In developing male germ cells, prospermatogonia, two Piwi proteins, MILI and MIWI2, use Piwi-interacting RNA (piRNA guides to repress transposable element (TE expression and ensure genome stability and proper gametogenesis. In addition to their roles in post-transcriptional TE repression, both proteins are required for DNA methylation of TE sequences. Here, we analyzed the effect of Miwi2 deficiency on piRNA biogenesis and transposon repression. Miwi2 deficiency had only a minor impact on piRNA biogenesis; however, the piRNA profile of Miwi2-knockout mice indicated overexpression of several LINE1 TE families that led to activation of the ping-pong piRNA cycle. Furthermore, we found that MILI and MIWI2 have distinct functions in TE repression in the nucleus. MILI is responsible for DNA methylation of a larger subset of TE families than MIWI2 is, suggesting that the proteins have independent roles in establishing DNA methylation patterns.

  10. Abundant primary piRNAs, endo-siRNAs, and microRNAs in a Drosophila ovary cell line.

    Science.gov (United States)

    Lau, Nelson C; Robine, Nicolas; Martin, Raquel; Chung, Wei-Jen; Niki, Yuzo; Berezikov, Eugene; Lai, Eric C

    2009-10-01

    Piwi proteins, a subclass of Argonaute-family proteins, carry approximately 24-30-nt Piwi-interacting RNAs (piRNAs) that mediate gonadal defense against transposable elements (TEs). We analyzed the Drosophila ovary somatic sheet (OSS) cell line and found that it expresses miRNAs, endogenous small interfering RNAs (endo-siRNAs), and piRNAs in abundance. In contrast to intact gonads, which contain mixtures of germline and somatic cell types that express different Piwi-class proteins, OSS cells are a homogenous somatic cell population that expresses only PIWI and primary piRNAs. Detailed examination of its TE-derived piRNAs and endo-siRNAs revealed aspects of TE defense that do not rely upon ping-pong amplification. In particular, we provide evidence that a subset of piRNA master clusters, including flamenco, are specifically expressed in OSS and ovarian follicle cells. These data indicate that the restriction of certain TEs in somatic gonadal cells is largely mediated by a primary piRNA pathway.

  11. Design on Ping-pong power management system of pipeline inspection robot%管道检测机器人乒乓供电管理系统设计

    Institute of Scientific and Technical Information of China (English)

    段颖妮

    2012-01-01

    油气输运管道内部探伤的管道机器人是工业特种机器人研究领域中热点,机器人在管道内作业过程中续航能力取决于机器人能量的如何获取和供电管理系统.本文针对此类问题设计并实现了管道机器人的自主发电,双电池组乒乓储能和供电的的管理机制,在两块电池一供一备的模式中,能够有效解决两块高能量锂离子电池之间充电、供电和电量检测自动切换,实现了双电池组的高效管理模式.%The pipeline robot used in oil and gas transport pipeline internal flaw detection is a hot spot in the field of industrial special robots.the robot in the operating process in the pipeline endurance depends on the robot how to obtain and supply of energy management systems. Pipeline robot designed for such problems-.to achieve self-power generation,dual battery pack ping-pong storage and supply management mechanism,the pattern of the two batteries for one is prepared the other is used, able to effectively solve two high-energy lithium-ion between the battery charging power supply and power to detect automatically switches to achieve efficient management of the dual battery pack.

  12. Ping-pong champion with adrenal insufficiency

    OpenAIRE

    2009-01-01

    A 62-year-old Japanese man, a bronze medal winner in the World Championship of table tennis when in his 20s, was diagnosed with secondary adrenocortical insufficiency due to isolated adrenocorticotropic hormone (ACTH) deficiency, and steroid administration was started. About 1 year after the diagnosis, he took part in a table tennis championship which was open to those 40 years or older. He took 10 mg hydrocortisone after breakfast as usual, played 10 matches, each of which took 20–30 min, an...

  13. An Atmospheric Pressure Ping-Pong "Ballometer"

    Science.gov (United States)

    Kazachkov, Alexander; Kryuchkov, Dmitriy; Willis, Courtney; Moore, John C.

    2006-01-01

    Classroom experiments on atmospheric pressure focus largely on demonstrating its existence, often in a most impressive way. A series of amusing physics demonstrations is widely known and practiced by educators teaching the topic. However, measuring the value of atmospheric pressure(P[subscript atm]) is generally done in a rather mundane way,…

  14. Adapting playware to multiple players

    DEFF Research Database (Denmark)

    Þorsteinsson, Arnar Tumi; Lund, Henrik Hautop; Mastorakis, Nikos

    2011-01-01

    With the creation of playware as intelligent hardware and software that creates play, it is possible to adapt the play tool to the individual user, and even to multiple users playing at the same time with the play tool. In this paper, we show how it is possible to implement adaptivity in modular...... to such differences, and argues that adaptivity is needed to make games fit to the individual users in both single-player games and multi-player games. As a case study, we implemented such adaptivity on modular interactive tiles for the single-user game ColorTimer, and for the multiple-user games PingPong, in which...

  15. Transposon defense by endo-siRNAs, piRNAs and somatic pilRNAs in Drosophila: contributions of Loqs-PD and R2D2.

    Directory of Open Access Journals (Sweden)

    Milijana Mirkovic-Hösle

    Full Text Available Transposable elements are a serious threat for genome integrity and their control via small RNA mediated silencing pathways is an ancient strategy. The fruit fly Drosophila melanogaster has two silencing activities that target transposons: endogenous siRNAs (esiRNAs or endo-siRNAs and Piwi-interacting small RNAs (piRNAs. The biogenesis of endo-siRNAs involves the Dicer-2 co-factors Loqs-PD, which acts predominantly during processing of dsRNA by Dcr-2, and R2D2, which primarily helps to direct siRNAs into the RNA interference effector Ago2. Nonetheless, loss of either protein is not sufficient to produce a phenotype comparable with a dcr-2 mutation. We provide further deep sequencing evidence supporting the notion that R2D2 and Loqs-PD have partially overlapping function. Certain transposons display a preference for either dsRBD-protein during production or loading; this appeared to correlate neither with overall abundance, classification of the transposon or a specific site of genomic origin. The endo-siRNA biogenesis pathway in germline operates according to the same principles as the existing model for the soma, and its impairment does not significantly affect piRNAs. Expanding the analysis, we confirmed the occurrence of somatic piRNA-like RNAs (pilRNAs that show a ping-pong signature. We detected expression of the Piwi-family protein mRNAs only barely above background, indicating that the somatic pilRNAs may arise from a small sub-population of somatic cells that express a functional piRNA pathway.

  16. Obama and Comeron's Ping-pong Diplomacy Show

    Institute of Scientific and Technical Information of China (English)

    李新

    2011-01-01

    They seemed like best mates. Every time one of them got a point, they did a high five(击掌相庆 ). The men were the British Prime Minister, David Cameron, and the President of the USA, Barack Obama.

  17. Obama and Cameron’s Ping-pong Diplomacy Show

    Institute of Scientific and Technical Information of China (English)

    李新

    2011-01-01

    They seemed like best mates. Every time one of them got a point,they did a high fiv(e击掌相庆). The men were the British Prime Minister,David Cameron, and the President of the USA, Barack Obama.The palling around(结伴玩耍)took place during Mr. Obama’s state

  18. Ping-pong modes: a new form of multipactor.

    Science.gov (United States)

    Kishek, R A

    2012-01-20

    The multipactor is a vacuum discharge based on a secondary electron emission. A novel resonant form is proposed that combines one- and two-surface impacts within a single period, provided the total transit time is an odd number of rf half-periods and the product of secondary yields exceeds unity. For low fD products, the simplest such mode is shown to significantly increase the upper electric field boundary of the multipacting region and lead to overlap of higher-order bands. The results agree nicely with 3D particle-in-cell code simulations. Practical implications of the findings are discussed.

  19. Ping Pong: Competing Leadership for Reform in EU Higher Education 1998-2006

    Science.gov (United States)

    Corbett, Anne

    2011-01-01

    How effective is EU cooperation in higher education? This article treats the issue as one of effectiveness in policy-making. What are the policy ideas which the EU wishes to feed into a policy domain where it has to operate largely through political cooperation and a modest degree of incentive funding? What outcomes are possible? The question is…

  20. 白纹伊蚊感染登革病毒后病毒特异性piRNAs分析%Dengue virus-derived piRNAs in Aedes albopictus

    Institute of Scientific and Technical Information of China (English)

    赖植发; 王衍海; 顾金保; 陈晓光

    2014-01-01

    Objective To screen and analyze Dengue virus-derived vsRNAs and piRNAs in Aedes albopictus.Methods Female adults Aedes albopictus were collected 2-4 days post-emergence and were injected with Dengue type 2 virus NGC strain,while control group were injected with equal volume of physiological saline.Total RNA was isolated,and small RNAs ranging up to 30 nt in length were excised and analyzed using Illumina HiSeq 2000.After removing adaptor sequences and contaminated reads,Clean reads were aligned to Dengue virus genome and its complementary sequence by SOAP2.The length,strand ratio nucleotide bias and genome distribution of Dengue virus-derived vsRNAs and vpiRNAs were further analyzed.Results Total,3835 vsRNAs and 395 vpiRNAs unique tags were obtained,among them 94.99% vpiRNAs were derived from virus genome strand,and distributed across the viral genome,but with an enrichment at several "hot-spots".Except weak bias for adenine at position 10 (10A)in the sense molecules as the feature of secondary piRNA,other signature piRNA characteristics were not observed,including a preference for a uridine at their 5'-end,which were main characteristics of primary piRNAs,and a significant 10 nt overlap (Ping-Pong)between sense and antisense piRNA.Conclusion Dengue virusderived piRNAs were indentified in Dengue virus infected Ae.albopictus.%目的 筛选并分析白纹伊蚊感染登革病毒后病毒特异性vsRNAs与vpiRNAs.方法 白纹伊蚊羽化后2~4d雌性成蚊显微注射DENV-2病毒NGC株,对照组注射生理盐水.8d后提取样品总RNA,分离小RNA,通过illumina Hiseq 2000测序仪进行测序分析.以SOAP2软件与DENV-2基因组和互补序列进行比对.对病毒特异性的vsRNAs与vpiRNAs的长度、碱基与链偏好性、基因组分布进行分析.结果 对于感染蚊虫,我们共计获得3835个特异的DENV-2来源的vsRNAs,其中395个特异性的vpiRNAs.94.99% vpiRNAs主要来源于病毒的正链基因组.vpiRNAs在DENV-2基因组上的分

  1. Detection of piRNAs in whitespotted bamboo shark liver.

    Science.gov (United States)

    Yang, Lingrong; Ge, Yinghua; Cheng, Dandan; Nie, Zuoming; Lv, Zhengbing

    2016-09-15

    Piwi-interacting RNAs (piRNAs) are 26 to 31-nt small non-coding RNAs that have been reported mostly in germ-line cells and cancer cells. However, the presence of piRNAs in the whitespotted bamboo shark liver has not yet been reported. In a previous study of microRNAs in shark liver, some piRNAs were detected from small RNAs sequenced by Solexa technology. A total of 4857 piRNAs were predicted and found in shark liver. We further selected 17 piRNAs with high and significantly differential expression between normal and regenerative liver tissues for subsequent verification by Northern blotting. Ten piRNAs were further identified, and six of these were matched to known piRNAs in piRNABank. The actual expression of six known and four novel piRNAs was validated by qRT-PCR. In addition, a total of 401 target genes of the 10 piRNAs were predicted by miRanda. Through GO and pathway function analyses, only five piRNAs could be annotated with eighteen GO annotations. The results indicated that the identified piRNAs are involved in many important biological responses, including immune inflammation, cell-specific differentiation and development, and angiogenesis. This manuscript provides the first identification of piRNAs in the liver of whitespotted bamboo shark using Solexa technology as well as further elucidation of the regulatory role of piRNAs in whitespotted bamboo shark liver. These findings may provide a useful resource and may facilitate the development of therapeutic strategies against liver damage.

  2. Without Argonaute3, Aubergine-bound piRNAs collapse but Piwi-bound piRNAs persist

    Science.gov (United States)

    Li, Chengjian; Vagin, Vasily V.; Lee, Soohyun; Xu, Jia; Ma, Shengmei; Xi, Hualin; Seitz, Hervé; Horwich, Michael D.; Syrzycka, Monika; Honda, Barry M.; Kittler, Ellen L.W.; Zapp, Maria L.; Klattenhoff, Carla; Schulz, Nadine; Theurkauf, William E.; Weng, Zhiping; Zamore, Phillip D.

    2009-01-01

    Summary Piwi-interacting RNAs (piRNAs) silence transposons in the germ line of animals. They are thought to derive from long primary transcripts spanning transposon-rich genomic loci, “piRNA clusters.” piRNAs are proposed to direct an auto-amplification loop in which an antisense piRNA, bound to Aubergine or Piwi protein, directs the cleavage of sense RNA, triggering production of a sense piRNA bound to the PIWI protein Argonaute3 (Ago3). In turn, the new piRNA is envisioned to direct cleavage of a cluster transcript, initiating production of a second antisense piRNA. Here, we describe strong loss-of-function mutations in ago3, allowing a direct genetic test of this model. We find that Ago3 acts to amplify piRNA pools and to enforce on them an antisense bias, increasing the number of piRNAs that can act to silence transposons. We also detect a second piRNA pathway centered on Piwi and functioning without benefit of Ago3-catalyzed amplification. Transposons targeted by this second pathway often reside in the flamenco locus, which is expressed in somatic ovarian follicle cells, suggesting a role for piRNAs beyond the germ line. PMID:19395009

  3. Collapse of germline piRNAs in the absence of Argonaute3 reveals somatic piRNAs in flies.

    Science.gov (United States)

    Li, Chengjian; Vagin, Vasily V; Lee, Soohyun; Xu, Jia; Ma, Shengmei; Xi, Hualin; Seitz, Hervé; Horwich, Michael D; Syrzycka, Monika; Honda, Barry M; Kittler, Ellen L W; Zapp, Maria L; Klattenhoff, Carla; Schulz, Nadine; Theurkauf, William E; Weng, Zhiping; Zamore, Phillip D

    2009-05-01

    Piwi-interacting RNAs (piRNAs) silence transposons in animal germ cells. piRNAs are thought to derive from long transcripts spanning transposon-rich genomic loci and to direct an autoamplification loop in which an antisense piRNA, bound to Aubergine or Piwi protein, triggers production of a sense piRNA bound to the PIWI protein Argonaute3 (Ago3). In turn, the new piRNA is envisioned to produce a second antisense piRNA. Here, we describe strong loss-of-function mutations in ago3, allowing a direct genetic test of this model. We find that Ago3 acts to amplify piRNA pools and to enforce on them an antisense bias, increasing the number of piRNAs that can act to silence transposons. We also detect a second, Ago3-independent piRNA pathway centered on Piwi. Transposons targeted by this second pathway often reside in the flamenco locus, which is expressed in somatic ovarian follicle cells, suggesting a role for piRNAs beyond the germline.

  4. mRNA profiles of piRNA pathway genes in emerald ash borer Agrilus planipennis

    Institute of Scientific and Technical Information of China (English)

    Omprakash Mittapalli; Praveen Mamidala; Swapna Priya Rajarapu

    2012-01-01

    Recent advances of Piwi-interacting RNAs (piRNAs) have enabled a better understanding of their putative roles in the protection of germ cells against selfish genetic elements.The germ plasm proteins namely,PIWI and VASA,are key players in regulation of piRNAs.However,the biogenesis of piRNAs remains poorly understood.We report the characterization and the transcript profiles of a PIWI and VASA gene in various tissues and developmental stages of the emerald ash borer (Agrilus planipennis),an exotic invasive insect pest that has attained a high impact status worldwide.The deduced amino acid sequences of both these genes (herein referred to "ApPIWI and ApVASA") revealed homology with similar proteins from other insect and non-insect taxa.Peak transcript levels for ApPIWI and ApVASA were observed in the ovaries (compared to the other tissues assayed) and in adults (compared to the other developmental stages assayed).To our knowledge this is the first report of profiling piRNA pathway genes in A.planipennis.These results provide new insights into the putative function of the PIWI and VASA proteins in insects.

  5. piRNAs and Their Functions in the Brain

    Science.gov (United States)

    Zuo, Lingjun; Wang, Zhiren; Tan, Yunlong; Chen, Xiangning; Luo, Xingguang

    2016-01-01

    Piwi-interacting RNAs (piRNAs) are the non-coding RNAs with 24–32 nucleotides (nt). They exhibit stark differences in length, expression pattern, abundance, and genomic organization when compared to micro-RNAs (miRNAs). There are hundreds of thousands unique piRNA sequences in each species. Numerous piRNAs have been identified and deposited in public databases. Since the piRNAs were originally discovered and well-studied in the germline, a few other studies have reported the presence of piRNAs in somatic cells including neurons. This paper reviewed the common features, biogenesis, functions, and distributions of piRNAs and summarized their specific functions in the brain. This review may provide new insights and research direction for brain disorders. PMID:27512315

  6. Conserved piRNA Expression from a Distinct Set of piRNA Cluster Loci in Eutherian Mammals.

    Science.gov (United States)

    Chirn, Gung-Wei; Rahman, Reazur; Sytnikova, Yuliya A; Matts, Jessica A; Zeng, Mei; Gerlach, Daniel; Yu, Michael; Berger, Bonnie; Naramura, Mayumi; Kile, Benjamin T; Lau, Nelson C

    2015-11-01

    The Piwi pathway is deeply conserved amongst animals because one of its essential functions is to repress transposons. However, many Piwi-interacting RNAs (piRNAs) do not base-pair to transposons and remain mysterious in their targeting function. The sheer number of piRNA cluster (piC) loci in animal genomes and infrequent piRNA sequence conservation also present challenges in determining which piC loci are most important for development. To address this question, we determined the piRNA expression patterns of piC loci across a wide phylogenetic spectrum of animals, and reveal that most genic and intergenic piC loci evolve rapidly in their capacity to generate piRNAs, regardless of known transposon silencing function. Surprisingly, we also uncovered a distinct set of piC loci with piRNA expression conserved deeply in Eutherian mammals. We name these loci Eutherian-Conserved piRNA cluster (ECpiC) loci. Supporting the hypothesis that conservation of piRNA expression across ~100 million years of Eutherian evolution implies function, we determined that one ECpiC locus generates abundant piRNAs antisense to the STOX1 transcript, a gene clinically associated with preeclampsia. Furthermore, we confirmed reduced piRNAs in existing mouse mutations at ECpiC-Asb1 and -Cbl, which also display spermatogenic defects. The Asb1 mutant testes with strongly reduced Asb1 piRNAs also exhibit up-regulated gene expression profiles. These data indicate ECpiC loci may be specially adapted to support Eutherian reproduction.

  7. Characterization of piRNAs across postnatal development in mouse brain

    KAUST Repository

    Ghosheh, Yanal

    2016-04-26

    PIWI-interacting RNAs (piRNAs) are responsible for maintaining the genome stability by silencing retrotransposons in germline tissues– where piRNAs were first discovered and thought to be restricted. Recently, novel functions were reported for piRNAs in germline and somatic cells. Using deep sequencing of small RNAs and CAGE of postnatal development of mouse brain, we identified piRNAs only in adult mouse brain. These piRNAs have similar sequence length as those of MILI-bound piRNAs. In addition, we predicted novel candidate regulators and putative targets of adult brain piRNAs.

  8. El Riesgo de la Mora en el fletamento: ¿Cómo un juego de Ping Pong?

    Directory of Open Access Journals (Sweden)

    Javier Andrés Franco Zárate

    2009-06-01

    Full Text Available Uno de los contratos más usados hoy en día para transportar mercancías por mar es el contrato de fletamento. El presente artículo pretende hacer una presentación general de los efectos de la “demora” que se puede presentar, tanto de parte del fletador como de parte del fletante, en el cumplimiento de sus compromisos contractuales bien en un contrato de fletamento por tiempo, bien en un contrato de fletamento por viaje.

  9. A New Method to Estimate Intrinsic Parameters in the Ping-pong Bisustrate Kinetic: Application to the Oxipolymerization of Phenol

    Directory of Open Access Journals (Sweden)

    José L. Gómez

    2005-01-01

    Full Text Available A new method for determining the intrinsic parameters of reaction in processes involving a high initial rate has been developed. The usefulness of this alternative, which consists of determining several sets of apparent parameters at different times and then extrapolating these to time zero, is demonstrated proved by the linear dependence obtained between the apparent parameters and the reaction time. The method permitted the values of the intrinsic parameters (enzyme specific activity and Michaelis-Menten constants of both substrates to be obtained for the system under study and was checked with experimental reaction rate data for the soybean peroxidase/phenol/hydrogen peroxide system.

  10. A conserved upstream motif orchestrates autonomous, germline-enriched expression of Caenorhabditis elegans piRNAs.

    Directory of Open Access Journals (Sweden)

    Allison C Billi

    Full Text Available Piwi-interacting RNAs (piRNAs fulfill a critical, conserved role in defending the genome against foreign genetic elements. In many organisms, piRNAs appear to be derived from processing of a long, polycistronic RNA precursor. Here, we establish that each Caenorhabditis elegans piRNA represents a tiny, autonomous transcriptional unit. Remarkably, the minimal C. elegans piRNA cassette requires only a 21 nucleotide (nt piRNA sequence and an ∼50 nt upstream motif with limited genomic context for expression. Combining computational analyses with a novel, in vivo transgenic system, we demonstrate that this upstream motif is necessary for independent expression of a germline-enriched, Piwi-dependent piRNA. We further show that a single nucleotide position within this motif directs differential germline enrichment. Accordingly, over 70% of C. elegans piRNAs are selectively expressed in male or female germline, and comparison of the genes they target suggests that these two populations have evolved independently. Together, our results indicate that C. elegans piRNA upstream motifs act as independent promoters to specify which sequences are expressed as piRNAs, how abundantly they are expressed, and in what germline. As the genome encodes well over 15,000 unique piRNA sequences, our study reveals that the number of transcriptional units encoding piRNAs rivals the number of mRNA coding genes in the C. elegans genome.

  11. Detection of PIWI and piRNAs in the mitochondria of mammalian cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, ChangHyuk, E-mail: netbuyer@hanmail.net [Cancer Genomics Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of); Tak, Hyosun, E-mail: chuberry@naver.com [Department of Biochemistry, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Rho, Mina, E-mail: minarho@hanyang.ac.kr [Department of Computer Science, Hanyang University, Seoul 133-791 (Korea, Republic of); Chang, Hae Ryung, E-mail: heyhae@ncc.re.kr [New Experimental Therapeutics Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of); Kim, Yon Hui, E-mail: yhkim@ncc.re.kr [New Experimental Therapeutics Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of); Kim, Kyung Tae, E-mail: bioktkim@ncc.re.kr [Molecular Epidemiology Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of); Balch, Curt, E-mail: curt.balch@gmail.com [Medical Sciences Program, Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Bloomington, IN 47405 (United States); Lee, Eun Kyung, E-mail: leeek@catholic.ac.kr [Department of Biochemistry, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Nam, Seungyoon, E-mail: seungyoon.nam@ncc.re.kr [Cancer Genomics Branch, National Cancer Center, Goyang 410-769 (Korea, Republic of)

    2014-03-28

    Highlights: • piRNA sequences were mapped to human mitochondrial (mt) genome. • We inspected small RNA-Seq datasets from somatic cell mt subcellular fractions. • Piwi and piRNA transcripts are present in mammalian somatic cancer cell mt fractions. - Abstract: Piwi-interacting RNAs (piRNAs) are 26–31 nt small noncoding RNAs that are processed from their longer precursor transcripts by Piwi proteins. Localization of Piwi and piRNA has been reported mostly in nucleus and cytoplasm of higher eukaryotes germ-line cells, where it is believed that known piRNA sequences are located in repeat regions of nuclear genome in germ-line cells. However, localization of PIWI and piRNA in mammalian somatic cell mitochondria yet remains largely unknown. We identified 29 piRNA sequence alignments from various regions of the human mitochondrial genome. Twelve out 29 piRNA sequences matched stem-loop fragment sequences of seven distinct tRNAs. We observed their actual expression in mitochondria subcellular fractions by inspecting mitochondrial-specific small RNA-Seq datasets. Of interest, the majority of the 29 piRNAs overlapped with multiple longer transcripts (expressed sequence tags) that are unique to the human mitochondrial genome. The presence of mature piRNAs in mitochondria was detected by qRT-PCR of mitochondrial subcellular RNAs. Further validation showed detection of Piwi by colocalization using anti-Piwil1 and mitochondria organelle-specific protein antibodies.

  12. Systematic characterization of seminal plasma piRNAs as molecular biomarkers for male infertility

    Science.gov (United States)

    Hong, Yeting; Wang, Cheng; Fu, Zheng; Liang, Hongwei; Zhang, Suyang; Lu, Meiling; Sun, Wu; Ye, Chao; Zhang, Chen-Yu; Zen, Ke; Shi, Liang; Zhang, Chunni; Chen, Xi

    2016-01-01

    Although piwi-interacting RNAs (piRNAs) play pivotal roles in spermatogenesis, little is known about piRNAs in the seminal plasma of infertile males. In this study, we systematically investigated the profiles of seminal plasma piRNAs in infertile males to identify piRNAs that are altered during infertility and evaluate their diagnostic value. Seminal plasma samples were obtained from 211 infertile patients (asthenozoospermia and azoospermia) and 91 fertile controls. High-throughput sequencing technology was employed to screen piRNA profiles in seminal plasma samples pooled from healthy controls and infertile patients. The results identified 61 markedly altered piRNAs in infertile patient groups compared with control group. Next, a quantitative RT-PCR assay was conducted in the training and validation sets to measure and confirm the concentrations of altered piRNAs. The results identified a panel of 5 piRNAs that were significantly decreased in seminal plasma of infertile patients compared with healthy controls. ROC curve analysis and risk score analysis revealed that the diagnostic potential of these 5 piRNAs to distinguish asthenozoospermic and azoospermic individuals from healthy controls was high. In summary, this study identifies a panel of piRNAs that can accurately distinguish fertile from infertile males. This finding may provide pathophysiological clues about the development of infertility. PMID:27068805

  13. A Happy 3' Ending to the piRNA Maturation Story.

    Science.gov (United States)

    Czech, Benjamin; Hannon, Gregory J

    2016-02-25

    For a decade, mystery has surrounded the mechanisms by which piRNA biogenesis yields distinct size classes of small RNAs within individual PIWI proteins. In this issue of Cell, two studies shed light on this process, identifying conserved PARN-family exonucleases that trim piRNAs to their mature size in silkworms and C. elegans.

  14. "Dot COM", a nuclear transit center for the primary piRNA pathway in Drosophila.

    Science.gov (United States)

    Dennis, Cynthia; Zanni, Vanessa; Brasset, Emilie; Eymery, Angeline; Zhang, Liang; Mteirek, Rana; Jensen, Silke; Rong, Yikang S; Vaury, Chantal

    2013-01-01

    The piRNA pathway protects genomes by silencing mobile elements. Despite advances in understanding the processing events that generate piRNAs for silencing, little is known about how primary transcripts are transported from their genomic clusters to their processing centers. Using a model of the Drosophila COM/flamenco locus in ovarian somatic cells, we identified a prominent nuclear structure called Dot COM, which is enriched in long transcripts from piRNA clusters but located far from their transcription sites. Remarkably, transcripts from multiple clusters accumulate at Dot COM, which is often juxtaposed with Yb-bodies, the cytoplasmic processing centers for cluster transcripts. Genetic evidence suggests that the accumulation of precursor transcripts at Dot COM represents one of the most upstream events in the piRNA pathway. Our results provide new insights into the initial steps of the piRNA pathway, and open up a new research area important for a complete understanding of this conserved pathway.

  15. Transcriptional properties and splicing of the flamenco piRNA cluster.

    Science.gov (United States)

    Goriaux, Coline; Desset, Sophie; Renaud, Yoan; Vaury, Chantal; Brasset, Emilie

    2014-04-01

    In Drosophila, the piRNA cluster, flamenco, produces most of the piRNAs (PIWI-interacting RNAs) that silence transposable elements in the somatic follicle cells during oogenesis. These piRNAs are thought to be processed from a long single-stranded precursor transcript. Here, we demonstrate that flamenco transcription is initiated from an RNA polymerase II promoter containing an initiator motif (Inr) and downstream promoter element (DPE) and requires the transcription factor, Cubitus interruptus. We show that the flamenco precursor transcript undergoes differential alternative splicing to generate diverse RNA precursors that are processed to piRNAs. Our data reveal dynamic processing steps giving rise to piRNA cluster precursors.

  16. Structure and function of Zucchini endoribonuclease in piRNA biogenesis.

    Science.gov (United States)

    Nishimasu, Hiroshi; Ishizu, Hirotsugu; Saito, Kuniaki; Fukuhara, Satoshi; Kamatani, Miharu K; Bonnefond, Luc; Matsumoto, Naoki; Nishizawa, Tomohiro; Nakanaga, Keita; Aoki, Junken; Ishitani, Ryuichiro; Siomi, Haruhiko; Siomi, Mikiko C; Nureki, Osamu

    2012-11-08

    PIWI-interacting RNAs (piRNAs) silence transposons to maintain genome integrity in animal germ lines. piRNAs are classified as primary and secondary piRNAs, depending on their biogenesis machinery. Primary piRNAs are processed from long non-coding RNA precursors transcribed from piRNA clusters in the genome through the primary processing pathway. Although the existence of a ribonuclease participating in this pathway has been predicted, its molecular identity remained unknown. Here we show that Zucchini (Zuc), a mitochondrial phospholipase D (PLD) superfamily member, is an endoribonuclease essential for primary piRNA biogenesis. We solved the crystal structure of Drosophila melanogaster Zuc (DmZuc) at 1.75 Å resolution. The structure revealed that DmZuc has a positively charged, narrow catalytic groove at the dimer interface, which could accommodate a single-stranded, but not a double-stranded, RNA. DmZuc and the mouse homologue MmZuc (also known as Pld6 and MitoPLD) showed endoribonuclease activity for single-stranded RNAs in vitro. The RNA cleavage products bear a 5'-monophosphate group, a hallmark of mature piRNAs. Mutational analyses revealed that the conserved active-site residues of DmZuc are critical for the ribonuclease activity in vitro, and for piRNA maturation and transposon silencing in vivo. We propose a model for piRNA biogenesis in animal germ lines, in which the Zuc endoribonuclease has a key role in primary piRNA maturation.

  17. The ribonuclease PARN-1 trims piRNA 3′ ends to promote transcriptome surveillance in C. elegans

    OpenAIRE

    Tang, Wen; Tu, Shikui; Lee, Heng-Chi; Weng, Zhiping; Mello, Craig C.

    2016-01-01

    piRNAs engage Piwi proteins to suppress transposons and are essential for fertility in diverse organisms. An interesting feature of piRNAs is that, while piRNA lengths are stereotypical within a species, they can differ widely between species. For example piRNAs are mainly 29 and 30 nucleotides in humans, 24 to 30 nucleotides in D. melanogaster, and uniformly 21 nucleotides in C. elegans. However, how piRNA length is determined and whether length impacts function remains unknown. Here we show...

  18. Somatic Primary piRNA Biogenesis Driven by cis-Acting RNA Elements and trans-Acting Yb

    Directory of Open Access Journals (Sweden)

    Hirotsugu Ishizu

    2015-07-01

    Full Text Available Primary piRNAs in Drosophila ovarian somatic cells arise from piRNA cluster transcripts and the 3′ UTRs of a subset of mRNAs, including Traffic jam (Tj mRNA. However, it is unclear how these RNAs are determined as primary piRNA sources. Here, we identify a cis-acting 100-nt fragment in the Tj 3′ UTR that is sufficient for producing artificial piRNAs from unintegrated DNA. These artificial piRNAs were effective in endogenous gene transcriptional silencing. Yb, a core component of primary piRNA biogenesis center Yb bodies, directly bound the Tj-cis element. Disruption of this interaction markedly reduced piRNA production. Thus, Yb is the trans-acting partner of the Tj-cis element. Yb-CLIP revealed that Yb binding correlated with somatic piRNA production but Tj-cis element downstream sequences produced few artificial piRNAs. We thus propose that Yb determines primary piRNA sources through two modes of action: primary binding to cis elements to specify substrates and secondary binding to downstream regions to increase diversity in piRNA populations.

  19. Natural variation of piRNA expression affects immunity to transposable elements

    Science.gov (United States)

    Radion, Elizaveta; Mironova, Anastasia; Akulenko, Natalia; Abramov, Yuri; Morgunova, Valeriya; Kordyukova, Maria Y.; Olovnikov, Ivan

    2017-01-01

    In the Drosophila germline, transposable elements (TEs) are silenced by PIWI-interacting RNA (piRNA) that originate from distinct genomic regions termed piRNA clusters and are processed by PIWI-subfamily Argonaute proteins. Here, we explore the variation in the ability to restrain an alien TE in different Drosophila strains. The I-element is a retrotransposon involved in the phenomenon of I-R hybrid dysgenesis in Drosophila melanogaster. Genomes of R strains do not contain active I-elements, but harbour remnants of ancestral I-related elements. The permissivity to I-element activity of R females, called reactivity, varies considerably in natural R populations, indicating the existence of a strong natural polymorphism in defense systems targeting transposons. To reveal the nature of such polymorphisms, we compared ovarian small RNAs between R strains with low and high reactivity and show that reactivity negatively correlates with the ancestral I-element-specific piRNA content. Analysis of piRNA clusters containing remnants of I-elements shows increased expression of the piRNA precursors and enrichment by the Heterochromatin Protein 1 homolog, Rhino, in weak R strains, which is in accordance with stronger piRNA expression by these regions. To explore the nature of the differences in piRNA production, we focused on two R strains, weak and strong, and showed that the efficiency of maternal inheritance of piRNAs as well as the I-element copy number are very similar in both strains. At the same time, germline and somatic uni-strand piRNA clusters generate more piRNAs in strains with low reactivity, suggesting the relationship between the efficiency of primary piRNA production and variable response to TE invasions. The strength of adaptive genome defense is likely driven by naturally occurring polymorphisms in the rapidly evolving piRNA pathway proteins. We hypothesize that hyper-efficient piRNA production is contributing to elimination of a telomeric retrotransposon He

  20. Specialized piRNA pathways act in germline and somatic tissues of the Drosophila ovary.

    Science.gov (United States)

    Malone, Colin D; Brennecke, Julius; Dus, Monica; Stark, Alexander; McCombie, W Richard; Sachidanandam, Ravi; Hannon, Gregory J

    2009-05-01

    In Drosophila gonads, Piwi proteins and associated piRNAs collaborate with additional factors to form a small RNA-based immune system that silences mobile elements. Here, we analyzed nine Drosophila piRNA pathway mutants for their impacts on both small RNA populations and the subcellular localization patterns of Piwi proteins. We find that distinct piRNA pathways with differing components function in ovarian germ and somatic cells. In the soma, Piwi acts singularly with the conserved flamenco piRNA cluster to enforce silencing of retroviral elements that may propagate by infecting neighboring germ cells. In the germline, silencing programs encoded within piRNA clusters are optimized via a slicer-dependent amplification loop to suppress a broad spectrum of elements. The classes of transposons targeted by germline and somatic piRNA clusters, though not the precise elements, are conserved among Drosophilids, demonstrating that the architecture of piRNA clusters has coevolved with the transposons that they are tasked to control.

  1. Probing the initiation and effector phases of the somatic piRNA pathway in Drosophila.

    Science.gov (United States)

    Haase, Astrid D; Fenoglio, Silvia; Muerdter, Felix; Guzzardo, Paloma M; Czech, Benjamin; Pappin, Darryl J; Chen, Caifu; Gordon, Assaf; Hannon, Gregory J

    2010-11-15

    Combining RNAi in cultured cells and analysis of mutant animals, we probed the roles of known Piwi-interacting RNA (piRNA) pathway components in the initiation and effector phases of transposon silencing. Squash associated physically with Piwi, and reductions in its expression led to modest transposon derepression without effects on piRNAs, consistent with an effector role. Alterations in Zucchini or Armitage reduced both Piwi protein and piRNAs, indicating functions in the formation of a stable Piwi RISC (RNA-induced silencing complex). Notably, loss of Zucchini or mutations within its catalytic domain led to accumulation of unprocessed precursor transcripts from flamenco, consistent with a role for this putative nuclease in piRNA biogenesis.

  2. Estudio cinético de la fase de transición del mecanismo trisustrato hexa uni ping-pong.

    OpenAIRE

    García Moreno, M.; García Cánovas, Francisco; Varón Castellanos, Ramón; García Carmona, Francisco; Tudela Serrano, José; Román Gil, A.

    1987-01-01

    El estudio cinético de las reacciones enzimáticas trisustrato se ha llevado a cabo bajo la aproximación del estado estacionario, la expresión de la ecuación de velocidad y sus distintas representaciones gráficas permiten distinguir entre los posibles mecanismos y obtener los parámetros cinéticos (KM y V^^,) que caracterizan al enzima actuando sobre los distintos sustratos (1-4). Sin embargo el enfoque en fase de transición, consigue una información más profunda ...

  3. Design and Implementation of Asynchronous FIFO Based on Ping-pong Operation%基于乒乓操作的异步FIFO设计及VHDL实现

    Institute of Scientific and Technical Information of China (English)

    王智; 罗新民

    2005-01-01

    目前的PLD(可编程逻辑器件)例如FPGA(现场可编程门阵列)凭借其灵活、方便、资源丰富的优势在很多领域得到了广泛应用.随着其片内存储资源的增加,把FIFO(先进先出)器件集成到PLD中是一种方便地代替专用FIFO芯片的实现方法.根据异步FIFO的设计方法,引入乒乓操作的设计技巧,给出了一种用FPGA实现异步FIFO的设计方案.

  4. Noncoding RNA. piRNA-guided slicing specifies transcripts for Zucchini-dependent, phased piRNA biogenesis.

    Science.gov (United States)

    Mohn, Fabio; Handler, Dominik; Brennecke, Julius

    2015-05-15

    In animal gonads, PIWI-clade Argonaute proteins repress transposons sequence-specifically via bound Piwi-interacting RNAs (piRNAs). These are processed from single-stranded precursor RNAs by largely unknown mechanisms. Here we show that primary piRNA biogenesis is a 3'-directed and phased process that, in the Drosophila germ line, is initiated by secondary piRNA-guided transcript cleavage. Phasing results from consecutive endonucleolytic cleavages catalyzed by Zucchini, implying coupled formation of 3' and 5' ends of flanking piRNAs. Unexpectedly, Zucchini also participates in 3' end formation of secondary piRNAs. Its function can, however, be bypassed by downstream piRNA-guided precursor cleavages coupled to exonucleolytic trimming. Our data uncover an evolutionarily conserved piRNA biogenesis mechanism in which Zucchini plays a central role in defining piRNA 5' and 3' ends. Copyright © 2015, American Association for the Advancement of Science.

  5. Selectively Constrained RNA Editing Regulation Crosstalks with piRNA Biogenesis in Primates.

    Science.gov (United States)

    Yang, Xin-Zhuang; Chen, Jia-Yu; Liu, Chu-Jun; Peng, Jiguang; Wee, Yin Rei; Han, Xiaorui; Wang, Chenqu; Zhong, Xiaoming; Shen, Qing Sunny; Liu, Hsuan; Cao, Huiqing; Chen, Xiao-Wei; Tan, Bertrand Chin-Ming; Li, Chuan-Yun

    2015-12-01

    Although millions of RNA editing events have been reported to modify hereditary information across the primate transcriptome, evidence for their functional significance remains largely elusive, particularly for the vast majority of editing sites in noncoding regions. Here, we report a new mechanism for the functionality of RNA editing-a crosstalk with PIWI-interacting RNA (piRNA) biogenesis. Exploiting rhesus macaque as an emerging model organism closely related to human, in combination with extensive genome and transcriptome sequencing in seven tissues of the same animal, we deciphered accurate RNA editome across both long transcripts and the piRNA species. Superimposing and comparing these two distinct RNA editome profiles revealed 4,170 editing-bearing piRNA variants, or epiRNAs, that primarily derived from edited long transcripts. These epiRNAs represent distinct entities that evidence an intersection between RNA editing regulations and piRNA biogenesis. Population genetics analyses in a macaque population of 31 independent animals further demonstrated that the epiRNA-associated RNA editing is maintained by purifying selection, lending support to the functional significance of this crosstalk in rhesus macaque. Correspondingly, these findings are consistent in human, supporting the conservation of this mechanism during the primate evolution. Overall, our study reports the earliest lines of evidence for a crosstalk between selectively constrained RNA editing regulation and piRNA biogenesis, and further illustrates that such an interaction may contribute substantially to the diversification of the piRNA repertoire in primates.

  6. Structural basis for piRNA 2'-O-methylated 3'-end recognition by Piwi PAZ (Piwi/Argonaute/Zwille) domains.

    Science.gov (United States)

    Tian, Yuan; Simanshu, Dhirendra K; Ma, Jin-Biao; Patel, Dinshaw J

    2011-01-18

    Argonaute and Piwi proteins are key players in the RNA silencing pathway, with the former interacting with micro-RNAs (miRNAs) and siRNAs, whereas the latter targets piwi-interacting RNAs (piRNAs) that are 2'-O-methylated (2(')-OCH(3)) at their 3' ends. Germline-specific piRNAs and Piwi proteins play a critical role in genome defense against transposable elements, thereby protecting the genome against transposon-induced defects in gametogenesis and fertility. Humans contain four Piwi family proteins designated Hiwi1, Hiwi2, Hiwi3, and Hili. We report on the structures of Hili-PAZ (Piwi/Argonaute/Zwille) domain in the free state and Hiwi1 PAZ domain bound to self-complementary 14-mer RNAs (12-bp + 2-nt overhang) containing 2(')-OCH(3) and 2'-OH at their 3' ends. These structures explain the molecular basis underlying accommodation of the 2(')-OCH(3) group within a preformed Hiwi1 PAZ domain binding pocket, whose hydrophobic characteristics account for the preferential binding of 2(')-OCH(3) over 2'-OH 3' ends. These results contrast with the more restricted binding pocket for the human Ago1 PAZ domain, which exhibits a reverse order, with preferential binding of 2'-OH over 2(')-OCH(3) 3' ends.

  7. Yb integrates piRNA intermediates and processing factors into perinuclear bodies to enhance piRISC assembly.

    Science.gov (United States)

    Murota, Yukiko; Ishizu, Hirotsugu; Nakagawa, Shinichi; Iwasaki, Yuka W; Shibata, Shinsuke; Kamatani, Miharu K; Saito, Kuniaki; Okano, Hideyuki; Siomi, Haruhiko; Siomi, Mikiko C

    2014-07-10

    PIWI-interacting RNAs (piRNAs) direct Piwi to repress transposons and maintain genome integrity in Drosophila ovarian somatic cells. piRNA maturation and association with Piwi occur at perinuclear Yb bodies, the centers of piRNA biogenesis. Here, we show that piRNA intermediates arising from the piRNA cluster flamenco (flam) localize to perinuclear foci adjacent to Yb bodies, termed Flam bodies. RNAi-based screening of piRNA factors revealed that Flam body formation depends on Yb, the core component of Yb bodies, while Piwi and another Yb body component, Armitage, are dispensable for formation. Abolishing the RNA-binding activity of Yb disrupts both Flam bodies and Yb bodies. Yb directly binds flam, but not transcripts from neighboring protein-coding genes. Thus, Yb integrates piRNA intermediates and piRNA processing factors selectively into Flam bodies and Yb bodies, respectively. We suggest that Yb is a key upstream factor in the cytoplasmic phase of the piRNA pathway in ovarian somatic cells. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Yb Integrates piRNA Intermediates and Processing Factors into Perinuclear Bodies to Enhance piRISC Assembly

    Directory of Open Access Journals (Sweden)

    Yukiko Murota

    2014-07-01

    Full Text Available PIWI-interacting RNAs (piRNAs direct Piwi to repress transposons and maintain genome integrity in Drosophila ovarian somatic cells. piRNA maturation and association with Piwi occur at perinuclear Yb bodies, the centers of piRNA biogenesis. Here, we show that piRNA intermediates arising from the piRNA cluster flamenco (flam localize to perinuclear foci adjacent to Yb bodies, termed Flam bodies. RNAi-based screening of piRNA factors revealed that Flam body formation depends on Yb, the core component of Yb bodies, while Piwi and another Yb body component, Armitage, are dispensable for formation. Abolishing the RNA-binding activity of Yb disrupts both Flam bodies and Yb bodies. Yb directly binds flam, but not transcripts from neighboring protein-coding genes. Thus, Yb integrates piRNA intermediates and piRNA processing factors selectively into Flam bodies and Yb bodies, respectively. We suggest that Yb is a key upstream factor in the cytoplasmic phase of the piRNA pathway in ovarian somatic cells.

  9. A somatic piRNA pathway in the Drosophila fat body ensures metabolic homeostasis and normal lifespan.

    Science.gov (United States)

    Jones, Brian C; Wood, Jason G; Chang, Chengyi; Tam, Austin D; Franklin, Michael J; Siegel, Emily R; Helfand, Stephen L

    2016-12-21

    In gonadal tissues, the Piwi-interacting (piRNA) pathway preserves genomic integrity by employing 23-29 nucleotide (nt) small RNAs complexed with argonaute proteins to suppress parasitic mobile sequences of DNA called transposable elements (TEs). Although recent evidence suggests that the piRNA pathway may be present in select somatic cells outside the gonads, the role of a non-gonadal somatic piRNA pathway is not well characterized. Here we report a functional somatic piRNA pathway in the adult Drosophila fat body including the presence of the piRNA effector protein Piwi and canonical 23-29 nt long TE-mapping piRNAs. The piwi mutants exhibit depletion of fat body piRNAs, increased TE mobilization, increased levels of DNA damage and reduced lipid stores. These mutants are starvation sensitive, immunologically compromised and short-lived, all phenotypes associated with compromised fat body function. These findings demonstrate the presence of a functional non-gonadal somatic piRNA pathway in the adult fat body that affects normal metabolism and overall organismal health.

  10. Discovery and Characterization of piRNAs in the Human Fetal Ovary

    Directory of Open Access Journals (Sweden)

    Zev Williams

    2015-10-01

    Full Text Available Piwi-interacting RNAs (piRNAs, a class of 26- to 32-nt non-coding RNAs (ncRNAs, function in germline development, transposon silencing, and epigenetic regulation. We performed deep sequencing and annotation of untreated and periodate-treated small RNA cDNA libraries from human fetal and adult germline and reference somatic tissues. This revealed abundant piRNAs originating from 150 piRNA-encoding genes, including some exhibiting gender-specific expression, in fetal ovary and adult testis—developmental periods coinciding with mitotic cell divisions expanding fetal germ cells prior to meiotic divisions. The absence of reads mapping uniquely to annotated piRNA genes demonstrated their paucity in fetal testis and adult ovary and absence in somatic tissues. We curated human piRNA-expressing regions and defined their precise borders and observed piRNA-guided cleavage of transcripts antisense to some piRNA-producing genes. This study provides insights into sex-specific mammalian piRNA expression and function and serves as a reference for human piRNA analysis and annotation.

  11. Veto players

    NARCIS (Netherlands)

    Warntjen, Andreas; Dowding, Keith

    2010-01-01

    Veto players are political actors whose consent is necessary to adopt a new policy. Put otherwise, they have veto power which allows them to prevent a change to the status quo. The concept is crucial to the influential veto player theory developed by George Tsebelis. Building on earlier work in form

  12. Veto players

    NARCIS (Netherlands)

    Warntjen, Andreas; Dowding, Keith

    2010-01-01

    Veto players are political actors whose consent is necessary to adopt a new policy. Put otherwise, they have veto power which allows them to prevent a change to the status quo. The concept is crucial to the influential veto player theory developed by George Tsebelis. Building on earlier work in form

  13. The piRNAs forge an immune system for the genome

    DEFF Research Database (Denmark)

    Muller, Sébastian; Pandey, R.R.; Pillai, R.S.

    2013-01-01

    or chromosomal rearrangements. The piRNA machinery ensures genomic integrity to germ cells by setting a response similar to the immune system. The recognition of the threat is mediated by sequence complementarity between a vast repertoire of piRNAs and the intruders, and initiates a rapid and efficient...... degradation of the targets. Akin to acquired immunity, the response is memorized throughout generations thanks to epigenetic modifications. Investigations are progressing to unravel the mysterious mechanisms of this exciting class of non coding RNAs. This review summarizes some of the recent advances...... on this exceptional immunity that protects transmission of genetic information....

  14. Multiplex bioimaging of piRNA molecular pathway-regulated theragnostic effects in a single breast cancer cell using a piRNA molecular beacon.

    Science.gov (United States)

    Lee, Youn Jung; Moon, Sung Ung; Park, Min Geun; Jung, Woon Yong; Park, Yong Keun; Song, Sung Kyu; Ryu, Je Gyu; Lee, Yong Seung; Heo, Hye Jung; Gu, Ha Na; Cho, Su Jeong; Ali, Bahy A; Al-Khedhairy, Abdulaziz A; Lee, Ilkyun; Kim, Soonhag

    2016-09-01

    Recently, PIWI-interacting small non-coding RNAs (piRNAs) have emerged as novel cancer biomarkers candidate because of their high expression level in various cancer types and role in the control of tumor suppressor genes. In this study, a novel breast cancer theragnostics probe based on a single system targeting the piRNA-36026 (piR-36026) molecular pathway was developed using a piR-36026 molecular beacon (MB). The piR-36026 MB successfully visualized endogenous piR-36026 biogenesis, which is highly expressed in MCF7 cells (a human breast cancer cell line), and simultaneously inhibited piR-36026-mediated cancer progression in vitro and in vivo. We discovered two tumor suppressor proteins, SERPINA1 and LRAT, that were directly regulated as endogenous piR-36026 target genes in MCF7 cells. Furthermore, multiplex bioimaging of a single MCF7 cell following treatment with piR-36026 MB clearly visualized the direct molecular interaction of piRNA-36026 with SERPINA1 or LRAT and subsequent molecular therapeutic responses including caspase-3 and PI in the nucleus.

  15. Discovery of piRNAs Pathway Associated with Early-Stage Spermatogenesis in Chicken.

    Science.gov (United States)

    Xu, Lu; Qiu, Lingling; Chang, Guobin; Guo, Qixin; Liu, Xiangping; Bi, Yulin; Zhang, Yu; Wang, Hongzhi; Li, Zhiteng; Guo, Xiaoming; Wan, Fang; Zhang, Yang; Xu, Qi; Chen, Guohong

    2016-01-01

    Piwi-interacting RNAs (piRNAs) play a key role in spermatogenesis. Here, we describe the piRNAs profiling of primordial germ cells (PGCs), spermatogonial stem cells (SSCs), and the spermatogonium (Sp) during early-stage spermatogenesis in chicken. We obtained 31,361,989 reads from PGCs, 31,757,666 reads from SSCs, and 46,448,327 reads from Sp cells. The length distribution of piRNAs in the three samples showed peaks at 33 nt. The resulting genes were subsequently annotated against the Gene Ontology (GO) database. Five genes (RPL7A, HSPA8, Pum1, CPXM2, and PRKCA) were found to be involved in cellular processes. Interactive pathway analysis (IPA) further revealed three important pathways in early-stage spermatogenesis including the FGF, Wnt, and EGF receptor signaling pathways. The gene Pum1 was found to promote germline stem cell proliferation, but it also plays a role in spermatogenesis. In conclusion, we revealed characteristics of piRNAs during early spermatogonial development in chicken and provided the basis for future research.

  16. Discovery of piRNAs Pathway Associated with Early-Stage Spermatogenesis in Chicken.

    Directory of Open Access Journals (Sweden)

    Lu Xu

    Full Text Available Piwi-interacting RNAs (piRNAs play a key role in spermatogenesis. Here, we describe the piRNAs profiling of primordial germ cells (PGCs, spermatogonial stem cells (SSCs, and the spermatogonium (Sp during early-stage spermatogenesis in chicken. We obtained 31,361,989 reads from PGCs, 31,757,666 reads from SSCs, and 46,448,327 reads from Sp cells. The length distribution of piRNAs in the three samples showed peaks at 33 nt. The resulting genes were subsequently annotated against the Gene Ontology (GO database. Five genes (RPL7A, HSPA8, Pum1, CPXM2, and PRKCA were found to be involved in cellular processes. Interactive pathway analysis (IPA further revealed three important pathways in early-stage spermatogenesis including the FGF, Wnt, and EGF receptor signaling pathways. The gene Pum1 was found to promote germline stem cell proliferation, but it also plays a role in spermatogenesis. In conclusion, we revealed characteristics of piRNAs during early spermatogonial development in chicken and provided the basis for future research.

  17. The mosquito Aedes aegypti has a large genome size and high transposable element load but contains a low proportion of transposon-specific piRNAs

    Science.gov (United States)

    2011-01-01

    Background The piRNA pathway has been shown in model organisms to be involved in silencing of transposons thereby providing genome stability. In D. melanogaster the majority of piRNAs map to these sequences. The medically important mosquito species Aedes aegypti has a large genome size, a high transposon load which includes Miniature Inverted repeat Transposable Elements (MITES) and an expansion of the piRNA biogenesis genes. Studies of transgenic lines of Ae. aegypti have indicated that introduced transposons are poorly remobilized and we sought to explore the basis of this. We wished to analyze the piRNA profile of Ae. aegypti and thereby determine if it is responsible for transposon silencing in this mosquito. Results Estimated piRNA sequence diversity was comparable between Ae. aegypti and D. melanogaster, but surprisingly only 19% of mosquito piRNAs mapped to transposons compared to 51% for D. melanogaster. Ae. aegypti piRNA clusters made up a larger percentage of the total genome than those of D. melanogaster but did not contain significantly higher percentages of transposon derived sequences than other regions of the genome. Ae. aegypti contains a number of protein coding genes that may be sources of piRNA biogenesis with two, traffic jam and maelstrom, implicated in this process in model organisms. Several genes of viral origin were also targeted by piRNAs. Examination of six mosquito libraries that had previously been transformed with transposon derived sequence revealed that new piRNA sequences had been generated to the transformed sequences, suggesting that they may have stimulated a transposon inactivation mechanism. Conclusions Ae. aegypti has a large piRNA complement that maps to transposons but primarily gene sequences, including many viral-derived sequences. This, together the more uniform distribution of piRNA clusters throughout its genome, suggest that some aspects of the piRNA system differ between Ae. aegypti and D. melanogaster. PMID:22171608

  18. Small RNA profiling and characterization of piRNA clusters in the adult testes of the common marmoset, a model primate.

    Science.gov (United States)

    Hirano, Takamasa; Iwasaki, Yuka W; Lin, Zachary Yu-Ching; Imamura, Masanori; Seki, Naomi M; Sasaki, Erika; Saito, Kuniaki; Okano, Hideyuki; Siomi, Mikiko C; Siomi, Haruhiko

    2014-08-01

    Small RNAs mediate gene silencing by binding Argonaute/Piwi proteins to regulate target RNAs. Here, we describe small RNA profiling of the adult testes of Callithrix jacchus, the common marmoset. The most abundant class of small RNAs in the adult testis was piRNAs, although 353 novel miRNAs but few endo-siRNAs were also identified. MARWI, a marmoset homolog of mouse MIWI and a very abundant PIWI in adult testes, associates with piRNAs that show characteristics of mouse pachytene piRNAs. As in other mammals, most marmoset piRNAs are derived from conserved clustered regions in the genome, which are annotated as intergenic regions. However, unlike in mice, marmoset piRNA clusters are also found on the X chromosome, suggesting escape from meiotic sex chromosome inactivation by the X-linked clusters. Some of the piRNA clusters identified contain antisense-orientated pseudogenes, suggesting the possibility that pseudogene-derived piRNAs may regulate parental functional protein-coding genes. More piRNAs map to transposable element (TE) subfamilies when they have copies in piRNA clusters. In addition, the strand bias observed for piRNAs mapped to each TE subfamily correlates with the polarity of copies inserted in clusters. These findings suggest that pachytene piRNA clusters determine the abundance and strand-bias of TE-derived piRNAs, may regulate protein-coding genes via pseudogene-derived piRNAs, and may even play roles in meiosis in the adult marmoset testis.

  19. The mosquito Aedes aegypti has a large genome size and high transposable element load but contains a low proportion of transposon-specific piRNAs

    Directory of Open Access Journals (Sweden)

    Arensburger Peter

    2011-12-01

    Full Text Available Abstract Background The piRNA pathway has been shown in model organisms to be involved in silencing of transposons thereby providing genome stability. In D. melanogaster the majority of piRNAs map to these sequences. The medically important mosquito species Aedes aegypti has a large genome size, a high transposon load which includes Miniature Inverted repeat Transposable Elements (MITES and an expansion of the piRNA biogenesis genes. Studies of transgenic lines of Ae. aegypti have indicated that introduced transposons are poorly remobilized and we sought to explore the basis of this. We wished to analyze the piRNA profile of Ae. aegypti and thereby determine if it is responsible for transposon silencing in this mosquito. Results Estimated piRNA sequence diversity was comparable between Ae. aegypti and D. melanogaster, but surprisingly only 19% of mosquito piRNAs mapped to transposons compared to 51% for D. melanogaster. Ae. aegypti piRNA clusters made up a larger percentage of the total genome than those of D. melanogaster but did not contain significantly higher percentages of transposon derived sequences than other regions of the genome. Ae. aegypti contains a number of protein coding genes that may be sources of piRNA biogenesis with two, traffic jam and maelstrom, implicated in this process in model organisms. Several genes of viral origin were also targeted by piRNAs. Examination of six mosquito libraries that had previously been transformed with transposon derived sequence revealed that new piRNA sequences had been generated to the transformed sequences, suggesting that they may have stimulated a transposon inactivation mechanism. Conclusions Ae. aegypti has a large piRNA complement that maps to transposons but primarily gene sequences, including many viral-derived sequences. This, together the more uniform distribution of piRNA clusters throughout its genome, suggest that some aspects of the piRNA system differ between Ae. aegypti and D

  20. Witness to 30 Years of China-U.S. Relations

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Jan Carol Berris has witnessed a series of events that made history for China-U.S. relations, including ping-pong diplomacy, the exchange of ping-pong players in the 1970s that eased the way for higher-level contact. She has overseen hundreds of American delegations to China and met many from China. She has traveled to China about 100 times with groups and individuals as diverse as a tennis team and a Supreme Court Justice. She is popular among different groups of people in China, who better recognize her Chinese name, Bai Lijuan. As both countries celebrate the 30th anniversary of normalization of China-U.S. diplomatic relations, Berris, Vice President of the National Committee on United States-China Relations, talks to Beijing Review reporter Chen Wen about her special experience of that particular period of history.

  1. The small RNA content of human sperm reveals pseudogene-derived piRNAs complementary to protein-coding genes

    Science.gov (United States)

    Pantano, Lorena; Jodar, Meritxell; Bak, Mads; Ballescà, Josep Lluís; Tommerup, Niels; Oliva, Rafael; Vavouri, Tanya

    2015-01-01

    At the end of mammalian sperm development, sperm cells expel most of their cytoplasm and dispose of the majority of their RNA. Yet, hundreds of RNA molecules remain in mature sperm. The biological significance of the vast majority of these molecules is unclear. To better understand the processes that generate sperm small RNAs and what roles they may have, we sequenced and characterized the small RNA content of sperm samples from two human fertile individuals. We detected 182 microRNAs, some of which are highly abundant. The most abundant microRNA in sperm is miR-1246 with predicted targets among sperm-specific genes. The most abundant class of small noncoding RNAs in sperm are PIWI-interacting RNAs (piRNAs). Surprisingly, we found that human sperm cells contain piRNAs processed from pseudogenes. Clusters of piRNAs from human testes contain pseudogenes transcribed in the antisense strand and processed into small RNAs. Several human protein-coding genes contain antisense predicted targets of pseudogene-derived piRNAs in the male germline and these piRNAs are still found in mature sperm. Our study provides the most extensive data set and annotation of human sperm small RNAs to date and is a resource for further functional studies on the roles of sperm small RNAs. In addition, we propose that some of the pseudogene-derived human piRNAs may regulate expression of their parent gene in the male germline. PMID:25904136

  2. Splicing-independent loading of TREX on nascent RNA is required for efficient expression of dual-strand piRNA clusters in Drosophila.

    Science.gov (United States)

    Hur, Junho K; Luo, Yicheng; Moon, Sungjin; Ninova, Maria; Marinov, Georgi K; Chung, Yun D; Aravin, Alexei A

    2016-04-01

    The conserved THO/TREX (transcription/export) complex is critical for pre-mRNA processing and mRNA nuclear export. In metazoa, TREX is loaded on nascent RNA transcribed by RNA polymerase II in a splicing-dependent fashion; however, how TREX functions is poorly understood. Here we show that Thoc5 and other TREX components are essential for the biogenesis of piRNA, a distinct class of small noncoding RNAs that control expression of transposable elements (TEs) in the Drosophila germline. Mutations in TREX lead to defects in piRNA biogenesis, resulting in derepression of multiple TE families, gametogenesis defects, and sterility. TREX components are enriched on piRNA precursors transcribed from dual-strand piRNA clusters and colocalize in distinct nuclear foci that overlap with sites of piRNA transcription. The localization of TREX in nuclear foci and its loading on piRNA precursor transcripts depend on Cutoff, a protein associated with chromatin of piRNA clusters. Finally, we show that TREX is required for accumulation of nascent piRNA precursors. Our study reveals a novel splicing-independent mechanism for TREX loading on nascent RNA and its importance in piRNA biogenesis.

  3. Selectively Constrained RNA Editing Regulation Crosstalks with piRNA Biogenesis in Primates

    OpenAIRE

    2015-01-01

    Although millions of RNA editing events have been reported to modify hereditary information across the primate transcriptome, evidence for their functional significance remains largely elusive, particularly for the vast majority of editing sites in noncoding regions. Here, we report a new mechanism for the functionality of RNA editing—a crosstalk with PIWI-interacting RNA (piRNA) biogenesis. Exploiting rhesus macaque as an emerging model organism closely related to human, in combination with ...

  4. Export of piRNA precursors by EJC triggers assembly of cytoplasmic Yb-body in Drosophila.

    Science.gov (United States)

    Dennis, Cynthia; Brasset, Emilie; Sarkar, Arpita; Vaury, Chantal

    2016-12-08

    PIWI-interacting RNAs (piRNAs) are effectors of transposable element (TE) silencing in the reproductive apparatus. In Drosophila ovarian somatic cells, piRNAs arise from longer single-stranded RNA precursors that are processed in the cytoplasm presumably within the Yb-bodies. piRNA precursors encoded by the flamenco (flam) piRNA cluster accumulate in a single focus away from their sites of transcription. In this study, we identify the exportin complex containing Nxf1 and Nxt1 as required for flam precursor nuclear export. Together with components of the exon junction complex (EJC), it is necessary for the efficient transfer of flam precursors away from their site of transcription. Indeed, depletion of these components greatly affects flam intra-nuclear transit. Moreover, we show that Yb-body assembly is dependent on the nucleo-cytoplasmic export of flam transcripts. These results suggest that somatic piRNA precursors are thus required for the assembly of the cytoplasmic transposon silencing machinery.

  5. “Dot COM”, a Nuclear Transit Center for the Primary piRNA Pathway in Drosophila

    Science.gov (United States)

    Brasset, Emilie; Eymery, Angeline; Zhang, Liang; Mteirek, Rana; Jensen, Silke; Rong, Yikang S.; Vaury, Chantal

    2013-01-01

    The piRNA pathway protects genomes by silencing mobile elements. Despite advances in understanding the processing events that generate piRNAs for silencing, little is known about how primary transcripts are transported from their genomic clusters to their processing centers. Using a model of the Drosophila COM/flamenco locus in ovarian somatic cells, we identified a prominent nuclear structure called Dot COM, which is enriched in long transcripts from piRNA clusters but located far from their transcription sites. Remarkably, transcripts from multiple clusters accumulate at Dot COM, which is often juxtaposed with Yb-bodies, the cytoplasmic processing centers for cluster transcripts. Genetic evidence suggests that the accumulation of precursor transcripts at Dot COM represents one of the most upstream events in the piRNA pathway. Our results provide new insights into the initial steps of the piRNA pathway, and open up a new research area important for a complete understanding of this conserved pathway. PMID:24039799

  6. Ancient and Novel Small RNA Pathways Compensate for the Loss of piRNAs in Multiple Independent Nematode Lineages

    Science.gov (United States)

    Sarkies, Peter; Selkirk, Murray E.; Jones, John T.; Blok, Vivian; Boothby, Thomas; Goldstein, Bob; Hanelt, Ben; Ardila-Garcia, Alex; Fast, Naomi M.; Schiffer, Phillip M.; Kraus, Christopher; Taylor, Mark J.; Koutsovoulos, Georgios; Blaxter, Mark L.; Miska, Eric A.

    2015-01-01

    Small RNA pathways act at the front line of defence against transposable elements across the Eukaryota. In animals, Piwi interacting small RNAs (piRNAs) are a crucial arm of this defence. However, the evolutionary relationships among piRNAs and other small RNA pathways targeting transposable elements are poorly resolved. To address this question we sequenced small RNAs from multiple, diverse nematode species, producing the first phylum-wide analysis of how small RNA pathways evolve. Surprisingly, despite their prominence in Caenorhabditis elegans and closely related nematodes, piRNAs are absent in all other nematode lineages. We found that there are at least two evolutionarily distinct mechanisms that compensate for the absence of piRNAs, both involving RNA-dependent RNA polymerases (RdRPs). Whilst one pathway is unique to nematodes, the second involves Dicer-dependent RNA-directed DNA methylation, hitherto unknown in animals, and bears striking similarity to transposon-control mechanisms in fungi and plants. Our results highlight the rapid, context-dependent evolution of small RNA pathways and suggest piRNAs in animals may have replaced an ancient eukaryotic RNA-dependent RNA polymerase pathway to control transposable elements. PMID:25668728

  7. Retrotransposon-centered analysis of piRNA targeting shows a shift from active to passive retrotransposon transcription in developing mouse testes

    DEFF Research Database (Denmark)

    Mourier, Tobias

    2011-01-01

    ABSTRACT: BACKGROUND: Piwi-associated RNAs (piRNAs) bind transcripts from retrotransposable elements (RTE) in mouse germline cells and seemingly act as guides for genomic methylation, thereby repressing the activity of RTEs. It is currently unknown if and how Piwi proteins distinguish RTE....... As expected, young RTEs display a much higher level of piRNA targeting than old RTEs. Further, irrespective of age, RTE loci near protein-coding coding genes are targeted to a greater extent than RTE loci far from genes. During development, a shift in piRNA targeting is observed, with a clear increase...... in the relative piRNA targeting of RTEs residing within boundaries of protein-coding gene transcripts. CONCLUSIONS: Reanalyzing published piRNA sequences and taking into account the features of individual RTE loci provide novel insight into the activity of RTEs during development. The obtained results...

  8. Recognition of 2'-O-methylated 3'-end of piRNA by the PAZ domain of a Piwi protein.

    Science.gov (United States)

    Simon, Bernd; Kirkpatrick, John P; Eckhardt, Stephanie; Reuter, Michael; Rocha, Elsa A; Andrade-Navarro, Miguel A; Sehr, Peter; Pillai, Ramesh S; Carlomagno, Teresa

    2011-02-09

    Piwi proteins are germline-specific Argonautes that associate with small RNAs called Piwi-interacting RNAs (piRNAs), and together with these RNAs are implicated in transposon silencing. The PAZ domain of Argonaute proteins recognizes the 3'-end of the RNA, which in the case of piRNAs is invariably modified with a 2'-O-methyl group. Here, we present the solution structure of the PAZ domain from the mouse Piwi protein, MIWI, in complex with an 8-mer piRNA mimic. The methyl group is positioned in a hydrophobic cavity made of conserved amino acids from strand β7 and helix α3, where it is contacted by the side chain of methionine-382. Our structure is similar to that of Ago-PAZ, but subtle differences illustrate how the PAZ domain has evolved to accommodate distinct 3' ends from a variety of RNA substrates.

  9. The small RNA content of human sperm reveals pseudogene-derived piRNAs complementary to protein-coding genes

    DEFF Research Database (Denmark)

    Pantano, Lorena; Jodar, Meritxell; Bak, Mads

    2015-01-01

    At the end of mammalian sperm development, sperm cells expel most of their cytoplasm and dispose of the majority of their RNA. Yet, hundreds of RNA molecules remain in mature sperm. The biological significance of the vast majority of these molecules is unclear. To better understand the processes......-specific genes. The most abundant class of small noncoding RNAs in sperm are PIWI-interacting RNAs (piRNAs). Surprisingly, we found that human sperm cells contain piRNAs processed from pseudogenes. Clusters of piRNAs from human testes contain pseudogenes transcribed in the antisense strand and processed...... that generate sperm small RNAs and what roles they may have, we sequenced and characterized the small RNA content of sperm samples from two human fertile individuals. We detected 182 microRNAs, some of which are highly abundant. The most abundant microRNA in sperm is miR-1246 with predicted targets among sperm...

  10. The Tudor domain protein Tapas, a homolog of the vertebrate Tdrd7, functions in the piRNA pathway to regulate retrotransposons in germline of Drosophila melanogaster.

    Science.gov (United States)

    Patil, Veena S; Anand, Amit; Chakrabarti, Alisha; Kai, Toshie

    2014-10-06

    Piwi-interacting RNAs (piRNAs) are a special class of small RNAs that provide defense against transposable elements in animal germline cells. In Drosophila, germline piRNAs are thought to be processed at a unique perinuclear structure, the nuage, that houses piRNA pathway proteins including the Piwi clade of Argonaute family proteins, along with several Tudor domain proteins, RNA helicases and nucleases. We previously demonstrated that Tudor domain protein Tejas (Tej), an ortholog of vertebrate Tdrd5, is an important component of the piRNA pathway. In the current study, we identified the paralog of the Drosophila tej gene, tapas (tap), which is an ortholog of vertebrate Tdrd7. Like Tej, Tap is localized at the nuage. Alone, tap loss leads to a mild increase in transposon expression and decrease in piRNAs targeting transposons expressed in the germline. The tap gene genetically interacts with other piRNA pathway genes and we also show that Tap physically interacts with piRNA pathway components, such as Piwi family proteins Aubergine and Argonaute3 and the RNA helicases Spindle-E and Vasa. Together with tej, tap is required for survival of germline cells during early stages and for polarity formation. We further observed that loss of tej and tap together results in more severe defects in the piRNA pathway in germline cells compared to single mutants: the double-mutant ovaries exhibit mis-localization of piRNA pathway components and significantly greater reduction of piRNAs against transposons predominantly expressed in germline compared to single mutants. The single or double mutants did not have any reduction in piRNAs mapping to transposons predominantly expressed in gonadal somatic cells or those derived from unidirectional clusters such as flamenco. Consistently, the loss of both tej and tap function resulted in mis-localization of Piwi in germline cells, whereas Piwi remained localized to the nucleus in somatic cells. Our observations suggest that tej and tap

  11. The “Special” crystal-Stellate System in Drosophila melanogaster Reveals Mechanisms Underlying piRNA Pathway-Mediated Canalization

    Directory of Open Access Journals (Sweden)

    Maria Pia Bozzetti

    2012-01-01

    Full Text Available The Stellate-made crystals formation in spermatocytes is the phenotypic manifestation of a disrupted crystal-Stellate interaction in testes of Drosophila melanogaster. Stellate silencing is achieved by the piRNA pathway, but many features still remain unknown. Here we outline the important role of the crystal-Stellate modifiers. These have shed light on the piRNA pathways that defend genome integrity against transposons and other repetitive elements in the gonads. In particular, we illustrate the finding that HSP90 participates in the molecular pathways of piRNA production. This observation has relevance for the mechanisms underlying the evolutionary canalization process.

  12. Crystal Structure and Activity of the Endoribonuclease Domain of the piRNA Pathway Factor Maelstrom

    Directory of Open Access Journals (Sweden)

    Naoki Matsumoto

    2015-04-01

    Full Text Available PIWI-interacting RNAs (piRNAs protect the genome from transposons in animal gonads. Maelstrom (Mael is an evolutionarily conserved protein, composed of a high-mobility group (HMG domain and a MAEL domain, and is essential for piRNA-mediated transcriptional transposon silencing in various species, such as Drosophila and mice. However, its structure and biochemical function have remained elusive. Here, we report the crystal structure of the MAEL domain from Drosophila melanogaster Mael, at 1.6 Å resolution. The structure reveals that the MAEL domain has an RNase H-like fold but lacks canonical catalytic residues conserved among RNase H-like superfamily nucleases. Our biochemical analyses reveal that the MAEL domain exhibits single-stranded RNA (ssRNA-specific endonuclease activity. Our cell-based analyses further indicate that ssRNA cleavage activity appears dispensable for piRNA-mediated transcriptional transposon silencing in Drosophila. Our findings provide clues toward understanding the multiple roles of Mael in the piRNA pathway.

  13. Abundant primary piRNAs, endo-siRNAs, and microRNAs in a Drosophila ovary cell line

    NARCIS (Netherlands)

    Lau, N.C.; Robine, N.; Martin, R.; Chung, W.J.; Niki, Y.; Berezikov, E.; Lai, E.C

    2009-01-01

    Piwi proteins, a subclass of Argonaute-family proteins, carry approximately 24-30-nt Piwi-interacting RNAs (piRNAs) that mediate gonadal defense against transposable elements (TEs). We analyzed the Drosophila ovary somatic sheet (OSS) cell line and found that it expresses miRNAs, endogenous small

  14. Distribution, evolution, and diversity of retrotransposons at the flamenco locus reflect the regulatory properties of piRNA clusters.

    Science.gov (United States)

    Zanni, Vanessa; Eymery, Angéline; Coiffet, Michael; Zytnicki, Matthias; Luyten, Isabelle; Quesneville, Hadi; Vaury, Chantal; Jensen, Silke

    2013-12-03

    Most of our understanding of Drosophila heterochromatin structure and evolution has come from the annotation of heterochromatin from the isogenic y; cn bw sp strain. However, almost nothing is known about the heterochromatin's structural dynamics and evolution. Here, we focus on a 180-kb heterochromatic locus producing Piwi-interacting RNAs (piRNA cluster), the flamenco (flam) locus, known to be responsible for the control of at least three transposable elements (TEs). We report its detailed structure in three different Drosophila lines chosen according to their capacity to repress or not to repress the expression of two retrotransposons named ZAM and Idefix, and we show that they display high structural diversity. Numerous rearrangements due to homologous and nonhomologous recombination, deletions and segmental duplications, and loss and gain of TEs are diverse sources of active genomic variation at this locus. Notably, we evidence a correlation between the presence of ZAM and Idefix in this piRNA cluster and their silencing. They are absent from flam in the strain where they are derepressed. We show that, unexpectedly, more than half of the flam locus results from recent TE insertions and that most of the elements concerned are prone to horizontal transfer between species of the melanogaster subgroup. We build a model showing how such high and constant dynamics of a piRNA master locus open the way to continual emergence of new patterns of piRNA biogenesis leading to changes in the level of transposition control.

  15. Crystal structure of the primary piRNA biogenesis factor Zucchini reveals similarity to the bacterial PLD endonuclease Nuc.

    Science.gov (United States)

    Voigt, Franka; Reuter, Michael; Kasaruho, Anisa; Schulz, Eike C; Pillai, Ramesh S; Barabas, Orsolya

    2012-12-01

    Piwi-interacting RNAs (piRNAs) are a gonad-specific class of small RNAs that associate with the Piwi clade of Argonaute proteins and play a key role in transposon silencing in animals. Since biogenesis of piRNAs is independent of the double-stranded RNA-processing enzyme Dicer, an alternative nuclease that can process single-stranded RNA transcripts has been long sought. A Phospholipase D-like protein, Zucchini, that is essential for piRNA processing has been proposed to be a nuclease acting in piRNA biogenesis. Here we describe the crystal structure of Zucchini from Drosophila melanogaster and show that it is very similar to the bacterial endonuclease, Nuc. The structure also reveals that homodimerization induces major conformational changes assembling the active site. The active site is situated on the dimer interface at the bottom of a narrow groove that can likely accommodate single-stranded nucleic acid substrates. Furthermore, biophysical analysis identifies protein segments essential for dimerization and provides insights into regulation of Zucchini's activity.

  16. piRNA-directed cleavage of meiotic transcripts regulates spermatogenesis.

    Science.gov (United States)

    Goh, Wee Siong Sho; Falciatori, Ilaria; Tam, Oliver H; Burgess, Ralph; Meikar, Oliver; Kotaja, Noora; Hammell, Molly; Hannon, Gregory J

    2015-05-15

    MIWI catalytic activity is required for spermatogenesis, indicating that piRNA-guided cleavage is critical for germ cell development. To identify meiotic piRNA targets, we augmented the mouse piRNA repertoire by introducing a human meiotic piRNA cluster. This triggered a spermatogenesis defect by inappropriately targeting the piRNA machinery to mouse mRNAs essential for germ cell development. Analysis of such de novo targets revealed a signature for pachytene piRNA target recognition. This enabled identification of both transposable elements and meiotically expressed protein-coding genes as targets of native piRNAs. Cleavage of genic targets began at the pachytene stage and resulted in progressive repression through meiosis, driven at least in part via the ping-pong cycle. Our data support the idea that meiotic piRNA populations must be strongly selected to enable successful spermatogenesis, both driving the response away from essential genes and directing the pathway toward mRNA targets that are regulated by small RNAs in meiotic cells.

  17. Telomeric Retrotransposon HeT-A Contains a Bidirectional Promoter that Initiates Divergent Transcription of piRNA Precursors in Drosophila Germline.

    Science.gov (United States)

    Radion, Elizaveta; Ryazansky, Sergei; Akulenko, Natalia; Rozovsky, Yakov; Kwon, Dmitry; Morgunova, Valeriya; Olovnikov, Ivan; Kalmykova, Alla

    2016-12-07

    PIWI-interacting RNAs (piRNAs) provide the silencing of transposable elements in the germline. Drosophila telomeres are maintained by transpositions of specialized telomeric retroelements. piRNAs generated from sense and antisense transcripts of telomeric elements provide telomere length control in the germline. Previously, we have found that antisense transcription of the major telomeric retroelement HeT-A is initiated upstream of the HeT-A sense transcription start site. Here, we performed a deletion analysis of the HeT-A promoter and show that common regulatory elements are shared by sense and antisense promoters of HeT-A. Therefore, the HeT-A promoter is a bidirectional promoter capable of processive sense and antisense transcription. Ovarian small RNA data show that a solo HeT-A promoter within an euchromatic transgene initiates the divergent transcription of transgenic reporter genes and subsequent processing of these transcripts into piRNAs. These events lead to the formation of a divergent unistrand piRNA cluster at solo HeT-A promoters, in contrast to endogenous telomeres that represent strong dual-strand piRNA clusters. Solo HeT-A promoters are not immunoprecipitated with heterochromatin protein 1 (HP1) homolog Rhino, a marker of the dual-strand piRNA clusters, but are associated with HP1 itself, which provides piRNA-mediated transcriptional repression of the reporter genes. Unlike endogenous dual-strand piRNA clusters, the solo HeT-A promoter does not produce overlapping transcripts. In a telomeric context, however, bidirectional promoters of tandem HeT-A repeats provide a read-through transcription of both genomic strands, followed by Rhi binding. These data indicate that Drosophila telomeres share properties of unistrand and dual-strand piRNA clusters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Study on the Application of Goal Orientation and Goal Setting Theory in Ping-pong Teaching%目标定向及目标设置理论在乒乓球教学中的应用研究

    Institute of Scientific and Technical Information of China (English)

    辛宪军

    2010-01-01

    运用专家调查和逻辑分析等方法,以乒乓球教学为切入点,以目标定向和目标设置为理论基础,着重解决乒乓球教学中普遍出现的学生练习中赢球心切但忽视基本功练习的现象,并对其中存在的有些问题提出解决策略.

  19. 实时图像处理器乒乓帧存结构%A real-time image processor based on ping-pong frame-storage structure

    Institute of Scientific and Technical Information of China (English)

    苏宛新

    2013-01-01

    With TMS320VC33 , EPF10K50 and CY7C1061BV33 , the hardware based on SRAM“Ping ,pong” frame-storage structure is designed .The working sequence and design key-point are analyzed .Under Quartus 8 and CC4 .1 ,VHDL ,AHDL ,C language driver and image process is programmed and debugged .The results show that the system can work stably at 1 280 × 1 024@60 Hz mode .T he system has been applied into industry .%利用TMS320VC33,EPF10K50和CY7C1061BV33研制了基于SRAM“乒、乓”帧存结构的硬件电路,并分析了工作时序和设计重点。在QuartusⅡ8.0及CC4.1的开发环境下,进行了V HDL ,A HDL ,C语言驱动和图像处理程序的编写和调试。结果表明,该系统在1280×1024@60 H z模式下能够稳定地工作,已得到了批量应用。

  20. Analysis of the small non-protein-coding RNA profile of mouse spermatozoa reveals specific enrichment of piRNAs within mature spermatozoa.

    Science.gov (United States)

    Hutcheon, Kate; McLaughlin, Eileen A; Stanger, Simone J; Bernstein, Ilana R; Dun, Matthew D; Eamens, Andrew L; Nixon, Brett

    2017-08-17

    Post-testicular sperm maturation and storage within the epididymis is a key determinant of gamete quality and fertilization competence. Here we demonstrate that mouse spermatozoa possess a complex small non-protein-coding RNA (sRNA) profile, the composition of which is markedly influenced by their epididymal transit. Thus, although miRNAs are highly represented in the spermatozoa of the proximal epididymis, this sRNA class is largely diminished in mature spermatozoa of the distal epididymis. Coincident with this, a substantial enrichment in Piwi-interacting RNA (piRNA) abundance in cauda spermatozoa was detected. Further, features of cauda piRNAs, including; predominantly 29-31 nts in length; preference for uracil at their 5' terminus; no adenine enrichment at piRNA nt 10, and; predominantly mapping to intergenic regions of the mouse genome, indicate that these piRNAs are generated by the PIWIL1-directed primary piRNA production pathway. Accordingly, PIWIL1 was detected via immunoblotting and mass spectrometry in epididymal spermatozoa. These data provide insight into the complexity and dynamic nature of the sRNA profile of spermatozoa and raise the intriguing prospect that piRNAs are generated in situ in maturing spermatozoa. Such information is of particular interest in view of the potential role for paternal sRNAs in influencing conception, embryo development and intergenerational inheritance.

  1. Retrotransposon-centered analysis of piRNA targeting shows a shift from active to passive retrotransposon transcription in developing mouse testes

    Directory of Open Access Journals (Sweden)

    Mourier Tobias

    2011-09-01

    Full Text Available Abstract Background Piwi-associated RNAs (piRNAs bind transcripts from retrotransposable elements (RTE in mouse germline cells and seemingly act as guides for genomic methylation, thereby repressing the activity of RTEs. It is currently unknown if and how Piwi proteins distinguish RTE transcripts from other cellular RNAs. During germline development, the main target of piRNAs switch between different types of RTEs. Using the piRNA targeting of RTEs as an indicator of RTE activity, and considering the entire population of genomic RTE loci along with their age and location, this study aims at further elucidating the dynamics of RTE activity during mouse germline development. Results Due to the inherent sequence redundancy between RTE loci, assigning piRNA targeting to specific loci is problematic. This limits the analysis, although certain features of piRNA targeting of RTE loci are apparent. As expected, young RTEs display a much higher level of piRNA targeting than old RTEs. Further, irrespective of age, RTE loci near protein-coding coding genes are targeted to a greater extent than RTE loci far from genes. During development, a shift in piRNA targeting is observed, with a clear increase in the relative piRNA targeting of RTEs residing within boundaries of protein-coding gene transcripts. Conclusions Reanalyzing published piRNA sequences and taking into account the features of individual RTE loci provide novel insight into the activity of RTEs during development. The obtained results are consistent with some degree of proportionality between what transcripts become substrates for Piwi protein complexes and the level by which the transcripts are present in the cell. A transition from active transcription of RTEs to passive co-transcription of RTE sequences residing within protein-coding transcripts appears to take place in postnatal development. Hence, the previously reported increase in piRNA targeting of SINEs in postnatal testis development

  2. Mutations to the piRNA pathway component aubergine enhance meiotic drive of segregation distorter in Drosophila melanogaster.

    Science.gov (United States)

    Gell, Selena L; Reenan, Robert A

    2013-03-01

    Diploid sexual reproduction involves segregation of allelic pairs, ensuring equal representation of genotypes in the gamete pool. Some genes, however, are able to "cheat" the system by promoting their own transmission. The Segregation distorter (Sd) locus in Drosophila melanogaster males is one of the best-studied examples of this type of phenomenon. In this system the presence of Sd on one copy of chromosome 2 results in dysfunction of the non-Sd-bearing (Sd(+)) sperm and almost exclusive transmission of Sd to the next generation. The mechanism by which Sd wreaks such selective havoc has remained elusive. However, its effect requires a target locus on chromosome 2 known as Responder (Rsp). The Rsp locus comprises repeated copies of a satellite DNA sequence and Rsp copy number correlates with sensitivity to Sd. Under distorting conditions during spermatogenesis, nuclei with chromosomes containing greater than several hundred Rsp repeats fail to condense chromatin and are eliminated. Recently, Rsp sequences were found as small RNAs in association with Argonaute family proteins Aubergine (Aub) and Argonaute3 (AGO3). These proteins are involved in a germline-specific RNAi mechanism known as the Piwi-interacting RNA (piRNA) pathway, which specifically suppresses transposon activation in the germline. Here, we evaluate the role of piRNAs in segregation distortion by testing the effects of mutations to piRNA pathway components on distortion. Further, we specifically targeted mutations to the aub locus of a Segregation Distorter (SD) chromosome, using ends-out homologous recombination. The data herein demonstrate that mutations to piRNA pathway components act as enhancers of SD.

  3. The Player Engagement Process

    DEFF Research Database (Denmark)

    Schoenau-Fog, Henrik

    2011-01-01

    Engagement is an essential element of the player experience, and the concept is described in various ways in the literature. To gain a more detailed comprehension of this multifaceted concept, and in order to better understand what aspects can be used to evaluate engaging game play and to design...... engaging user experiences, this study investigates one dimension of player engagement by empirically identifying the components associated with the desire to continue playing. Based on a description of the characteristics of player engagement, a series of surveys were developed to discover the components......, categories and triggers involved in this process. By applying grounded theory to the analysis of the responses, a process-oriented player engagement framework was developed and four main components consisting of objectives, activities, accomplishments and affects as well as the corresponding categories...

  4. piRNA pathway targets active LINE1 elements to establish the repressive H3K9me3 mark in germ cells.

    Science.gov (United States)

    Pezic, Dubravka; Manakov, Sergei A; Sachidanandam, Ravi; Aravin, Alexei A

    2014-07-01

    Transposable elements (TEs) occupy a large fraction of metazoan genomes and pose a constant threat to genomic integrity. This threat is particularly critical in germ cells, as changes in the genome that are induced by TEs will be transmitted to the next generation. Small noncoding piwi-interacting RNAs (piRNAs) recognize and silence a diverse set of TEs in germ cells. In mice, piRNA-guided transposon repression correlates with establishment of CpG DNA methylation on their sequences, yet the mechanism and the spectrum of genomic targets of piRNA silencing are unknown. Here we show that in addition to DNA methylation, the piRNA pathway is required to maintain a high level of the repressive H3K9me3 histone modification on long interspersed nuclear elements (LINEs) in germ cells. piRNA-dependent chromatin repression targets exclusively full-length elements of actively transposing LINE families, demonstrating the remarkable ability of the piRNA pathway to recognize active elements among the large number of genomic transposon fragments.

  5. Characterization of Sus scrofa small non-coding RNAs present in both female and male gonads.

    Science.gov (United States)

    Kowalczykiewicz, Dorota; Świercz, Aleksandra; Handschuh, Luiza; Leśniak, Katarzyna; Figlerowicz, Marek; Wrzesinski, Jan

    2014-01-01

    Small non-coding RNAs (sncRNAs) are indispensable for proper germ cell development, emphasizing the need for greater elucidation of the mechanisms of germline development and regulation of this process by sncRNAs. We used deep sequencing to characterize three families of small non-coding RNAs (piRNAs, miRNAs, and tRFs) present in Sus scrofa gonads and focused on the small RNA fraction present in both male and female gonads. Although similar numbers of reads were obtained from both types of gonads, the number of unique RNA sequences in the ovaries was several times lower. Of the sequences detected in the testes, 2.6% of piRNAs, 9% of miRNAs, and 10% of tRFs were also present in the ovaries. Notably, the majority of the shared piRNAs mapped to ribosomal RNAs and were derived from clustered loci. In addition, the most abundant miRNAs present in the ovaries and testes are conserved and are involved in many biological processes such as the regulation of homeobox genes, the control of cell proliferation, and carcinogenesis. Unexpectedly, we detected a novel sncRNA type, the tRFs, which are 30-36-nt RNA fragments derived from tRNA molecules, in gonads. Analysis of S. scrofa piRNAs show that testes specific piRNAs are biased for 5' uracil but both testes and ovaries specific piRNAs are not biased for adenine at the 10th nucleotide position. These observations indicate that adult porcine piRNAs are predominantly produced by a primary processing pathway or other mechanisms and secondary piRNAs generated by ping-pong mechanism are absent.

  6. Characterization of Sus scrofa small non-coding RNAs present in both female and male gonads.

    Directory of Open Access Journals (Sweden)

    Dorota Kowalczykiewicz

    Full Text Available Small non-coding RNAs (sncRNAs are indispensable for proper germ cell development, emphasizing the need for greater elucidation of the mechanisms of germline development and regulation of this process by sncRNAs. We used deep sequencing to characterize three families of small non-coding RNAs (piRNAs, miRNAs, and tRFs present in Sus scrofa gonads and focused on the small RNA fraction present in both male and female gonads. Although similar numbers of reads were obtained from both types of gonads, the number of unique RNA sequences in the ovaries was several times lower. Of the sequences detected in the testes, 2.6% of piRNAs, 9% of miRNAs, and 10% of tRFs were also present in the ovaries. Notably, the majority of the shared piRNAs mapped to ribosomal RNAs and were derived from clustered loci. In addition, the most abundant miRNAs present in the ovaries and testes are conserved and are involved in many biological processes such as the regulation of homeobox genes, the control of cell proliferation, and carcinogenesis. Unexpectedly, we detected a novel sncRNA type, the tRFs, which are 30-36-nt RNA fragments derived from tRNA molecules, in gonads. Analysis of S. scrofa piRNAs show that testes specific piRNAs are biased for 5' uracil but both testes and ovaries specific piRNAs are not biased for adenine at the 10th nucleotide position. These observations indicate that adult porcine piRNAs are predominantly produced by a primary processing pathway or other mechanisms and secondary piRNAs generated by ping-pong mechanism are absent.

  7. History of the discovery of a master locus producing piRNAs: the flamenco/COM locus in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Coline eGoriaux

    2014-08-01

    Full Text Available The discovery of transposable elements (TEs in the 1950s by B. McClintock implied the existence of cellular regulatory systems controlling TE activity. The discovery of flam an heterochromatic locus from Drosophila melanogaster and its ability to survey several TEs such as gypsy, ZAM and Idefix contributed to peer deeply into the mechanisms of the genetic and epigenetic regulation of TEs. flam was the first cluster producing small RNAs to be discovered long before RNAi pathways were identified in 1998. As a result of the detailed genetic analyses performed by certain laboratories and of the sophisticated genetic tools they developed, this locus has played a major role in our understanding of piRNA mediated TE repression in animals. Here we review the first discovery of this locus and retrace decades of studies that led to our current understanding of the relationship between genomes and their TE targets.

  8. History of the discovery of a master locus producing piRNAs: the flamenco/COM locus in Drosophila melanogaster.

    Science.gov (United States)

    Goriaux, Coline; Théron, Emmanuelle; Brasset, Emilie; Vaury, Chantal

    2014-01-01

    The discovery of transposable elements (TEs) in the 1950s by B. McClintock implied the existence of cellular regulatory systems controlling TE activity. The discovery of flamenco (flam) an heterochromatic locus from Drosophila melanogaster and its ability to survey several TEs such as gypsy, ZAM, and Idefix contributed to peer deeply into the mechanisms of the genetic and epigenetic regulation of TEs. flam was the first cluster producing small RNAs to be discovered long before RNAi pathways were identified in 1998. As a result of the detailed genetic analyses performed by certain laboratories and of the sophisticated genetic tools they developed, this locus has played a major role in our understanding of piRNA mediated TE repression in animals. Here we review the first discovery of this locus and retrace decades of studies that led to our current understanding of the relationship between genomes and their TE targets.

  9. Active Learning for Player Modeling

    DEFF Research Database (Denmark)

    Shaker, Noor; Abou-Zleikha, Mohamed; Shaker, Mohammad

    2015-01-01

    Learning models of player behavior has been the focus of several studies. This work is motivated by better understanding of player behavior, a knowledge that can ultimately be employed to provide player-adapted or personalized content. In this paper, we propose the use of active learning for player...... experience modeling. We use a dataset from hundreds of players playing Infinite Mario Bros. as a case study and we employ the random forest method to learn mod- els of player experience through the active learning approach. The results obtained suggest that only part of the dataset (up to half the size...... of the full dataset) is necessary for the construction of accu- rate models that are as accurate as those constructed from the full dataset. This indicates the potential of the method and its benefits in cases when obtaining the data is expensive or time, storage or effort consuming. The results also indicate...

  10. Active Learning for Player Modeling

    DEFF Research Database (Denmark)

    Shaker, Noor; Abou-Zleikha, Mohamed; Shaker, Mohammad

    2015-01-01

    Learning models of player behavior has been the focus of several studies. This work is motivated by better understanding of player behavior, a knowledge that can ultimately be employed to provide player-adapted or personalized content. In this paper, we propose the use of active learning for player...... experience modeling. We use a dataset from hundreds of players playing Infinite Mario Bros. as a case study and we employ the random forest method to learn mod- els of player experience through the active learning approach. The results obtained suggest that only part of the dataset (up to half the size...... of the full dataset) is necessary for the construction of accu- rate models that are as accurate as those constructed from the full dataset. This indicates the potential of the method and its benefits in cases when obtaining the data is expensive or time, storage or effort consuming. The results also indicate...

  11. Expression of the Argonaute protein PiwiL2 and piRNAs in adult mouse mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qiuling; Ma, Qi; Shehadeh, Lina A.; Wilson, Amber; Xia, Linghui; Yu, Hong [Department of Molecular and Cellular Pharmacology, Vascular Biology Institute, University of Miami Miller School of Medicine, Miami, FL 33136 (United States); Webster, Keith A., E-mail: kwebster@med.miami.edu [Department of Molecular and Cellular Pharmacology, Vascular Biology Institute, University of Miami Miller School of Medicine, Miami, FL 33136 (United States)

    2010-06-11

    Piwi (P-element-induced wimpy testis) first discovered in Drosophila is a member of the Argonaute family of micro-RNA binding proteins with essential roles in germ-cell development. The murine homologue of PiwiL2, also known as Mili is selectively expressed in the testes, and mice bearing targeted mutations of the PiwiL2 gene are male-sterile. PiwiL2 proteins are thought to protect the germ line genome by suppressing retrotransposons, stabilizing heterochromatin structure, and regulating target genes during meiosis and mitosis. Here, we report that PiwiL2 and associated piRNAs (piRs) may play similar roles in adult mouse mesenchymal stem cells. We found that PiwiL2 is expressed in the cytoplasm of metaphase mesenchymal stem cells from the bone marrow of adult and aged mice. Knockdown of PiwiL2 with a specific siRNA enhanced cell proliferation, significantly increased the number of cells in G1/S and G2/M cell cycle phases and was associated with increased expression of cell cycle genes CCND1, CDK8, microtubule regulation genes, and decreased expression of tumor suppressors Cables 1, LATS, and Cxxc4. The results suggest broader roles for Piwi in genome surveillance beyond the germ line and a possible role in regulating the cell cycle of mesenchymal stem cells.

  12. Co-option of the piRNA pathway for germline-specific alternative splicing of C. elegans TOR.

    Science.gov (United States)

    Barberán-Soler, Sergio; Fontrodona, Laura; Ribó, Anna; Lamm, Ayelet T; Iannone, Camilla; Cerón, Julián; Lehner, Ben; Valcárcel, Juan

    2014-09-25

    Many eukaryotic genes contain embedded antisense transcripts and repetitive sequences of unknown function. We report that male germline-specific expression of an antisense transcript contained in an intron of C. elegans Target of Rapamycin (TOR, let-363) is associated with (1) accumulation of endo-small interfering RNAs (siRNAs) against an embedded Helitron transposon and (2) activation of an alternative 3' splice site of TOR. The germline-specific Argonaute proteins PRG-1 and CSR-1, which participate in self/nonself RNA recognition, antagonistically regulate the generation of these endo-siRNAs, TOR mRNA levels, and 3' splice-site selection. Supply of exogenous double-stranded RNA against the region of sense/antisense overlap reverses changes in TOR expression and splicing and suppresses the progressive multigenerational sterility phenotype of prg-1 mutants. We propose that recognition of a "nonself" intronic transposon by endo-siRNAs/the piRNA system provides physiological regulation of expression and alternative splicing of a host gene that, in turn, contributes to the maintenance of germline function across generations.

  13. Multi-Player Quantum Games

    CERN Document Server

    Benjamin, S C; Benjamin, Simon C.; Hayden, Patrick M.

    2001-01-01

    Game theory is a mature field of applied mathematics. It formalizes the conflict between competing agents, and has found applications ranging from economics through to biology. Recently the first efforts have been made to introduce quantum information into game theory. For two-player games, it has been found that when the allowed `moves' are extended to include everything quantum mechanically possible, then the predominant strategies in the game can disappear, and only reappear if the players degrade the quantum coherence. Here we present the first study of quantum games with more than two players. We demonstrate that such games can exhibit `coherent' equilibrium strategies which have no analogue in classical games, or even in two-player quantum games. These equilibria are generally of a cooperative nature: quantum players can exploit their environment highly efficiently through the use of collaborative strategies.

  14. The multiple Tudor domain-containing protein TDRD1 is a molecular scaffold for mouse Piwi proteins and piRNA biogenesis factors

    Science.gov (United States)

    Mathioudakis, Nikolas; Palencia, Andres; Kadlec, Jan; Round, Adam; Tripsianes, Konstantinos; Sattler, Michael; Pillai, Ramesh S.; Cusack, Stephen

    2012-01-01

    Piwi-interacting RNAs (piRNAs) are small noncoding RNAs expressed in the germline of animals. They associate with Argonaute proteins of the Piwi subfamily, forming ribonucleoprotein complexes that are involved in maintaining genome integrity. The N-terminal region of some Piwi proteins contains symmetrically dimethylated arginines. This modification is thought to enable recruitment of Tudor domain-containing proteins (TDRDs), which might serve as platforms mediating interactions between various proteins in the piRNA pathway. We measured the binding affinity of the four individual extended Tudor domains (TDs) of murine TDRD1 protein for three different methylarginine-containing peptides from murine Piwi protein MILI. The results show a preference of TD2 and TD3 for consecutive MILI peptides, whereas TD4 and TD1 have, respectively, lower and very weak affinity for any peptide. The affinity of TD1 for methylarginine peptides can be restored by a single-point mutation back to the consensus aromatic cage sequence. These observations were confirmed by pull-down experiments with endogenous Piwi and Piwi-associated proteins. The crystal structure of TD3 bound to a methylated MILI peptide shows an unexpected orientation of the bound peptide, with additional contacts of nonmethylated residues being made outside of the aromatic cage, consistent with solution NMR titration experiments. Finally, the molecular envelope of the four tandem Tudor domains of TDRD1, derived from small angle scattering data, reveals a flexible, elongated shape for the protein. Overall, the results show that TDRD1 can accommodate different peptides from different proteins, and can therefore act as a scaffold protein for complex assembly in the piRNA pathway. PMID:22996915

  15. Diplomacy Gets a Sporting Chance

    Institute of Scientific and Technical Information of China (English)

    ROSEANNE; GERIN

    2007-01-01

    The United States steps up to the plate and uses sport to improve its image in China Two teams of table tennis players from opposite sides of the world cracked the icy relations between China and the United States in 1971 when they played a series of exhibi- tion matches in Beijing.While the nine American players were in the capital city of China,they met with Chinese students and workers,attended social events and visited the Great Wall and Summer Palace.This ping-pong diplomacy helped to pave the way for the then President Richard Nixon’s historic trip to China the following year—the first ever for a U.S.president—and the beginning of rapprochement between the two Cold War adversaries.

  16. The Edubox Learning Design Player

    NARCIS (Netherlands)

    Tattersall, Colin; Vogten, Hubert; Hermans, Henry

    2005-01-01

    Tattersall, C., Vogten, H. & Hermans, H. (2005). The Edubox Learning Design Player. In: Koper, R. & Tattersall, C., Learning Design: A Handbook on Modelling and Delivering Networked Education and Training (pp. 303-310). Berlin-Heidelberg: Springer Verlag.

  17. The Astro Learning Design Player

    NARCIS (Netherlands)

    Sharples, Paul; Wilson, Scott; Popat, Kris; Griffiths, David; Beauvoir, Phillip

    2010-01-01

    Sharples, Paul Wilson, S., Popat, K., Griffiths, D., Beauvoir, P. (2009) The Astro Learning Design Player. This software is distributed under the three clause BSD license, copyright TENCompetence Foundation

  18. The Edubox Learning Design Player

    NARCIS (Netherlands)

    Tattersall, Colin; Vogten, Hubert; Hermans, Henry

    2005-01-01

    Tattersall, C., Vogten, H. & Hermans, H. (2005). The Edubox Learning Design Player. In: Koper, R. & Tattersall, C., Learning Design: A Handbook on Modelling and Delivering Networked Education and Training (pp. 303-310). Berlin-Heidelberg: Springer Verlag.

  19. Examination of Exhaustive Cloning Attempts Reveals that C. elegans piRNAs, Transposons, and Repeat Sequences are Efficiently Cloned in Yeast, but not in Bacteria

    Directory of Open Access Journals (Sweden)

    Or eSagy

    2014-08-01

    Full Text Available Genome sequencing requires insertion of random fragments of the sequenced organism’s DNA into a unicellular host, most often E. coli bacteria. This manipulation was found in the past to be analogous to naturally occurring horizontal gene transfer, and moreover has proved valuable to understanding toxicity of foreign genetic elements to E. coli. Sequencing of the C. elegans genome was similarly achieved via DNA transformation into E. coli. However, numerous attempts have proven a significant percentage of the genome unclonable using bacteria, although clonable via yeast. We examined the genomic segments that were not in bacteria but in yeast, and observed that, in line with previous hypotheses, such sequences are more repetitive on average compared with the entire C. elegans genome. In addition, we found that these gap-sequences encode significantly more for DNA transposons. Surprisingly, we discovered that although the vast majority of the C. elegans genome is in bacteria (77.5%, almost all the thousands of sequences that encode for PIWI-interacting small RNAs, or 21U-RNAs (91.6% were only in yeast. These results might help understanding why most piRNAs in C.elegans are physically clustered on particular loci on chromosome IV. In worms and in a large number of other organisms, piRNAs serve to distinguish Self from Non-Self sequences, and thus to protect the integrity of the genome against foreign genetic elements, such as transposons. We discuss the possible implications of these discoveries

  20. Frontal Lobe Function in Chess Players

    Directory of Open Access Journals (Sweden)

    Vahid Nejati

    2012-05-01

    Full Text Available Chess is considered as a cognitive game because of severe engagement of the mental resources during playing. The purpose of this study is evaluation of frontal lobe function of chess players with matched non-players. Wisconsin Card Sorting Test (WCST data showed no difference between the player and non-player groups in preservation error and completed categories but surprisingly showed significantly lower grade of the player group in correct response. Our data reveal that chess players dont have any preference in any stage of Stroop test. Chess players dont have any preference in selective attention, inhibition and executive cognitive function. Chess players' have lower shifting abilities than non-players.

  1. The Effectiveness Evaluation among Different Player-Matching Mechanisms in a Multi-Player Quiz Game

    Science.gov (United States)

    Tsai, Fu-Hsing

    2016-01-01

    This study aims to investigate whether different player-matching mechanisms in educational multi-player online games (MOGs) can affect students' learning performance, enjoyment perception and gaming behaviors. Based on the multi-player quiz game, TRIS-Q, developed by Tsai, Tsai and Lin (2015) using a free player-matching (FPM) mechanism, the same…

  2. The NBA’s Maximum Player Salary and the Distribution of Player Rents

    Directory of Open Access Journals (Sweden)

    Kelly M. Hastings

    2015-03-01

    Full Text Available The NBA’s 1999 Collective Bargaining Agreement (CBA included provisions capping individual player pay in addition to team payrolls. This study examines the effect the NBA’s maximum player salary on player rents by comparing player pay from the 1997–1998 and 2003–2004 seasons while controlling for player productivity and other factors related to player pay. The results indicate a large increase in the pay received by teams’ second highest and, to a lesser extent, third highest paid players. We interpret this result as evidence that the adoption of the maximum player salary shifted rents from stars to complementary players. We also show that the 1999 CBA’s rookie contract provisions reduced salaries of early career players.

  3. A Comprehensive NGS Data Analysis of Differentially Regulated miRNAs, piRNAs, lncRNAs and sn/snoRNAs in Triple Negative Breast Cancer

    Science.gov (United States)

    Koduru, Srinivas V; Tiwari, Amit K; Leberfinger, Ashley; Hazard, Sprague W; Kawasawa, Yuka Imamura; Mahajan, Milind; Ravnic, Dino J

    2017-01-01

    Cancer is the second leading cause of death in the United States and is a major public health concern worldwide. Basic, clinical and epidemiological research is leading to improved cancer detection, prevention, and outcomes. Recent technological advances have allowed unbiased and comprehensive screening of genome-wide gene expression. Small non-coding RNAs (sncRNAs) have been shown to play an important role in biological processes and could serve as a diagnostic, prognostic and therapeutic biomarker for specific diseases. Recent findings have begun to reveal and enhance our understanding of the complex architecture of sncRNA expression including miRNAs, piRNAs, lncRNAs, sn/snoRNAs and their relationships with biological systems. We used publicly available small RNA sequencing data that was derived from 24 triple negative breast cancers (TNBC) and 14 adjacent normal tissue samples to remap various types of sncRNAs. We found a total of 55 miRNAs were aberrantly expressed (p<0.005) in TNBC samples (8 miRNAs upregulated; 47 downregulated) compared to adjacent normal tissues whereas the original study reported only 25 novel miRs. In this study, we used pathway analysis of differentially expressed miRNAs which revealed TGF-beta signaling pathways to be profoundly affected in the TNBC samples. Furthermore, our comprehensive re-mapping strategy allowed us to discover a number of other differentially expressed sncRNAs including piRNAs, lncRNAs, sn/snoRNAs, rRNAs, miscRNAs and nonsense-mediated decay RNAs. We believe that our sncRNA analysis workflow is extremely comprehensive and suitable for discovery of novel sncRNAs changes, which may lead to the development of innovative diagnostic and therapeutic tools for TNBC.

  4. Psychological games of entangled players

    CERN Document Server

    Zak, Michail

    2012-01-01

    The paper introduces a new approach to theory of differential games in which entangled players try to predict and influence actions of their adversaries. The entanglement is generated be a joint probability density known by the players. Incase of complex density, its imaginary part represents a measure of uncertainty of the density distribution. The novelty of the approach is in non-Newtonian mathematical formalism thatis based upon a behavioral model of Livings. The model is quantum-inspired: it represented by a modified Madelung equation which the quantum potential is replaced by different, specially chosen "computational" potential. It consists of motor dynamics simulating actual behavior of the object, and mental dynamics representing evolution of the corresponding knowledge-based and incorporating this knowledge in the for m of information flows into the motor dynamics. Due to feedback from mental dynamics, motor dynamics attains quantum-like properties: its trajectory splits into a family of different t...

  5. Two-Player Graph Pebbling

    Science.gov (United States)

    Prudente, Matthew James

    Given a graph G with pebbles on the vertices, we define a pebbling move as removing two pebbles from a vertex u, placing one pebble on a neighbor v, and discarding the other pebble, like a toll. The pebbling number pi( G) is the least number of pebbles needed so that every arrangement of pi(G) pebbles can place a pebble on any vertex through a sequence of pebbling moves. We introduce a new variation on graph pebbling called two-player pebbling. In this, players called the mover and the defender alternate moves, with the stipulation that the defender cannot reverse the previous move. The mover wins only if they can place a pebble on a specified vertex and the defender wins if the mover cannot. We define η(G), analogously, as the minimum number of pebbles such that given every configuration of the η( G) pebbles and every specified vertex r, the mover has a winning strategy. First, we will investigate upper bounds for η( G) on various classes of graphs and find a certain structure for which the defender has a winning strategy, no matter how many pebbles are in a configuration. Then, we characterize winning configurations for both players on a special class of diameter 2 graphs. Finally, we show winning configurations for the mover on paths using a recursive argument.

  6. Motivational profile quality players handball

    Directory of Open Access Journals (Sweden)

    Alfonso Martínez Moreno

    2017-06-01

    Full Text Available In the sport context, elite category, it is necessary to know all the factors, which in one way or another, affect the athletes throughout the different competitions. The object of study is to know the motivational profile of elite handball players. The sample consisted of 495 players, of whom 47.8% were boys and 52.2% girls, their ages ranged from 12 to 16 years, with an average of 13.8 years (dt = 1.0. Descriptive statistical analyzes of the sample, absolute and relative frequencies were performed for the qualitative variables and for the quantitative values minimum, maximum, mean, standard deviation, Cronbach's alpha. Correlation between variables, with the Pearson correlation coefficient. The MANCOVA test was performed to determine if there were differences between the dimensions of the questionnaire, according to age and years of practice. The results reveal that handball players elite category of the sample object of study have mainly intrinsic motivation, achieving high scores on general motivation, motivation achievement and motivation stimulation. In addition to moderately high values in introjected regulation and very low values in demotivation.

  7. [Dietary behaviours of volleyball and basketball players].

    Science.gov (United States)

    Szczepańska, Elzbieta; Spałkowska, Agnieszka

    2012-01-01

    In sports, such as basketball and volleyball, players must demonstrate the speed, strength, stamina and concentration. Correct nutrition affects the strength of the muscles and the extension of capacity. It is also necessary for the proper functioning of the nervous system and determines the rate of regeneration after physical effort. The aim of this study was to assess dietary behaviours of professional volleyball and basketball players and compare the prevalence of correct behaviours in both groups. 209 professional volleyball and basketball players from sports clubs localized in six Silesian cities were survived with the mean of author questionnaire. The chi-square test was used to examine differences in the prevalence of the correct behaviours among players. Analysis of the results obtained showed that 52% of the players had 4-5 meals a day. 35% of respondents had wholemeal bread and/or groats daily. Milk and dairy products daily ate 71% of surveyed players, meat and sausages 70% respectively. 41% of respondents had cottage cheese and 28% had fish several times a week. Vegetables and fruit were eaten by 21% and respectively 23% of respondents. Sweets were eaten daily by 40% of surveyed, while fast-food were eaten several times a week by 17% of players. Nutrients for athletes were used by 32%, and vitamin supplementation by 48% of respondents. Prevalence of correct dietary behaviour in the group of professional volleyball and basketball players differed. Basketball players statistically more frequently than volleyball players had 4-5 meals a day, had wholemeal bread and/or thick groats, milk and dairy products, meat and sausages, especially poultry. They had raw vegetables and fruit several times a day. They drank more than 2.5 liters of fluids per day. They also significantly more frequently than volleyball players consumed the fast-food occasionally or never. Dietary behaviours of surveyed players were incorrect. Comparison of prevalence of proper behaviours

  8. Vitamin D Deficiency Among Professional Basketball Players.

    Science.gov (United States)

    Fishman, Matthew P; Lombardo, Stephen J; Kharrazi, F Daniel

    2016-07-01

    Vitamin D plays an important role in several systems of the human body. Various studies have linked vitamin D deficiency to stress and insufficiency fractures, muscle recovery and function, and athletic performance. The prevalence of vitamin D deficiency in the elite athletic population has not been extensively studied, and very few reports exist among professional athletes. There is a high prevalence of vitamin D deficiency or insufficiency among players attending the National Basketball Association (NBA) Combine. Cross-sectional study; Level of evidence, 3. This is a retrospective review of data previously collected as part of the routine medical evaluation of players in the NBA Combines from 2009 through 2013. Player parameters evaluated were height, weight, body mass index (BMI), and vitamin D level. Statistical analysis using t tests and analysis of variance was used to detect any correlation between the player parameters and vitamin D level. Vitamin D levels were categorized as deficient (32 ng/mL). After institutional review board approval was submitted to the NBA, the NBA released deidentified data on 279 players who participated in the combines from 2009 through 2013. There were 90 players (32.3%) who were deficient, 131 players (47.0%) who were insufficient, and 58 players (20.8%) who were sufficient. A total of 221 players (79.3%) were either vitamin D deficient or insufficient. Among all players included, the average vitamin D level was 25.6 ± 10.2 ng/mL. Among the players who were deficient, insufficient, and sufficient, the average vitamin D levels were 16.1 ± 2.1 ng/mL, 25.0 ± 3.4 ng/mL, and 41.6 ± 8.6 ng/mL, respectively. Player height and weight were significantly increased in vitamin D-sufficient players compared with players who were not sufficient (P = .0008 and .009, respectively). Player age and BMI did not significantly differ depending on vitamin D status (P = .15 and .77, respectively). There is a high prevalence of vitamin D deficiency

  9. Player-character dynamics in multi-player Role Playing Games

    DEFF Research Database (Denmark)

    Tychsen, Anders; McIlwain, Doris; Brolund, Thea

    2007-01-01

    This paper presents the results of a comprehensive empirical study of the impact of integrating complex game characters in multi-player Role Playing Games across tabletop and digital formats. Players were provided with characters that had detailed background history, personality and goals. Player...... and player engagement with their character and no correlation between enjoyment and similarity between player and character personality. © 2007 Authors & Digital Games Research Association (DiGRA)....... and character personality were assessed using the Extended Personal Attributes Questionnaire (EPAQ) and further questionnaires administered to measure player enjoyment and the player-character relationship. Results include a high level of player enjoyment across all formats, a high correlation between enjoyment...

  10. An investigation of player to player character identification via personal pronouns

    DEFF Research Database (Denmark)

    Hichens, Michael; Drachen, Anders; Richards, Deborah

    2012-01-01

    The player character is an important feature of many games, where it is through the character that the player interacts with game world. There has been considerable interest in the relationship between the player and the player character. Much of this work has examined the identification of players...... in playing video games, did have a statistically significant affect, indicating that different levels of identification are more dependent on the player than on the game. This indicates that players are not a homogeneous group with respect to player character identification and is an important consideration...... with their characters, generally taking either a textual analysis approach, or has been empirical work that has explicitly identified the idea of identification through survey instruments, etc. The work presented here takes a different empirical approach, focusing on the use of various pronoun forms (first, second...

  11. Serious eye injury in badminton players.

    Science.gov (United States)

    Kelly, S P

    1987-10-01

    Serious eye injury can occur in badminton players and may become more frequent. The causes and nature of such injuries in this sport in six patients are discussed. All were playing competitive doubles matches. Penetrating eye injury due to a shattered glass spectacle lens occurred. Players should be advised not to wear spectacles with glass lenses. Ocular protection in this sport is desirable, and the forward player should hold the racket in front of the face.

  12. The Prevalence of Injuries in Professional Turkish Soccer Players

    Science.gov (United States)

    Yamaner, Faruk; Gumusdag, Hayrettin; Kartal, Alparslan; Gumus, M.; Gullu, A.; Imamoglu, O.

    2011-01-01

    Study aim: To assess the prevalence and anatomical sites of injuries in professional soccer players in one game season. Material and methods: A cohort of 510 professional male soccer players consisting of 48 goalkeepers, 194 defence players, 189 mid-field players and 79 forward players of the 1st and 2nd Turkish Professional Soccer Leagues in…

  13. Chess players' fame versus their merit

    CERN Document Server

    Simkin, M V

    2015-01-01

    We investigate a pool of international chess title holders born between 1901 and 1943. Using Elo ratings we compute for every player his expected score in a game with a randomly selected player from the pool. We use this figure as player's merit. We measure players' fame as the number of Google hits. The correlation between fame and merit is 0.38. At the same time the correlation between the logarithm of fame and merit is 0.61. This suggests that fame grows exponentially with merit.

  14. Physiological characteristics of international female soccer players.

    Science.gov (United States)

    Manson, Sarah A; Brughelli, Matt; Harris, Nigel K

    2014-02-01

    The purpose of this study was to investigate the physiological characteristics of Fédération Internationale de Football Association (FIFA) eligible international female soccer players aged 14-36 years and to determine if measures were significantly different for players selected (i.e., starters) to the starting line up for an FIFA tournament as compared with those not selected (i.e., nonstarters). Fifty-one (N = 18 Under 17; N = 18 Under 20; N = 15 Senior) international female soccer players participated in this study. The subjects underwent measurements of anthropometry (height and body mass), lower body strength (isokinetic testing), sprint kinetics and kinematics (nonmotorized treadmill), leg power (unilateral jumping), and maximal aerobic velocity (30:15 intermittent fitness test) during the final preparatory stage for an FIFA event. Outcomes of the age group data indicate that differences in physiological capacities are evident for the Under 17 players as compared with those for the Under 20 and Senior capped international players, suggesting a plateau in the acquisition of physical qualities as players mature. Starters tended to be faster (effect size [ES] = 0.55-1.0, p velocity (ES = 0.78-2.45, p velocity (ES = 0.87, p players, where maximal aerobic velocity was the primary difference between starters and nonstarters (ES = 0.83-2.45, p players. Coaches should emphasize the development of speed, maximal aerobic velocity, and leg strength in developing female soccer players.

  15. 鹌鹁PiRNAs和Piwil1基因克隆及表达研究%Cloning and Expression Analysis of piRNAs and Piwill Gene in Quail

    Institute of Scientific and Technical Information of China (English)

    陈蓉; 常国斌; 张颖; 陈国宏; 胡国顺; 栾德琴; 刘艳; 戴爱琴

    2011-01-01

    [Objcetive]A study on small RNA and its binding protein in poultry was carried out in order to provide a basic foundation for the study of genetic characters, occurrence and disappearance mechanisms of small RNAs in avain and transgenic chicken in avian.[Mehtod]The sequences of piRNAs and CDS of the Piwill gene were acquired from the testis of quail by constructing cDNA library and TA cloning and sequencing.Next, the expressions of piRNAs and Piwil1 in quail tissues of different stages of life were analyzed by Q-PCR.[Result]Ithis study, we obtained Thirty piRNAs cloned sequences and CDS of the Piwill gene were obtained from the testis of quail for the first time.The results of Q-PCR showed that piRNAs and Piwil1 genes had a variable expression in quail tissues of different stages of life.[Conclusion]The results showed that the length of quail piRNAs was similar to mammals.In quail, Piwil1 gene had high homology with that of the red jungle fowl, whose protein contains the PAZ and Piwi domain, and has no signal peptide splice site, suggesting that it belong to Piwi family and might play a regulatory role by reducing the capacity of binding RNA or affecting the affinity between other transcription factors and the promoter of structural gene.In testis, the expression of piRNAs and Piwil1 gene increased with the development of individuals, so it was inferred that piRNAs might regulate the process of spermatogenesis through interacting with Piwi proteins in poultry.%[目的]目前,国内外尚无有关禽类piRNAs及其结合蛋白Piwi的研究报道,开展禽类小分子RNA及其结合蛋白的研究将为小分子RNA的遗传特性、发生和消失机理以及转基因鸡等研究提供基础依据.[方法]以鹌鹑为研究对象,通过构建eDNA文库和TA克隆测序的方法从睾丸组织中获得piRNAs序列和Piwill基因的CDS序列,同时采用Q-PCR技术分析了鹌鹑不同生命阶段不同组织中piRNAs和Piwill基因的表达规律.[结果]从

  16. Cooperation: New Players in Africa

    Directory of Open Access Journals (Sweden)

    Philippe Hugon

    2010-03-01

    Full Text Available In the context of globalisation and the current global financial crisis, new players are emerging in cooperation in Africa. These partners loosen financial constraints and conditionalities, increase the room for manoeuvre and stimulate commodity markets. On the other hand, they also increase the risks of renewed indebtedness and potentially weaken the coordination of aid policies. Do these partnerships call the new cooperation practices of OECD countries into question? Do they justify the return to a realpolitik or are they repeating the earlier mistakes of industrial powers? Can these mistakes be corrected? The question also arises as to whether the global crisis, which has a profound effect on Africa, will lead to a withdrawal or to a passing of the baton on to new, emerging powers. This article highlights the new geopolitical issues concerning Africa in a multipolar world, then discusses the new players involved in cooperation in Africa, before going on to explore the horizons that are opening up for cooperation in Africa, in particular with regard to the global crisis.

  17. The potential risk of personal stereo players

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Ordoñez, Rodrigo Pizarro; Reuter, Karen

    2010-01-01

    The technological development within personal stereo systems, such as MP3 players, e. g. iPods, has changed music listening habits from home entertainment to everyday and everywhere use. The technology has developed considerably, since the introduction of cassette players and CD walkmen. High...

  18. The potential risk of personal stereo players

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Ordoñez, Rodrigo Pizarro; Reuter, Karen

    2010-01-01

    The technological development within personal stereo systems,such as MP3 players, e. g. iPods, has changed music listening habits from home entertainment to everyday and everywhere use. The technology has developed considerably, since the introduction of cassette players and CD walkmen. High...

  19. Who Are the Players in Canadian Curriculum?

    Science.gov (United States)

    Milburn, Geoffrey

    1987-01-01

    Labels range of persons advocating different theoretical positions of Canadian curriculum as "players." Describes players as "managers,""predictors,""transformers,""sleuths,""analysts." Values varied viewpoints for attention to language regarding curriculum, critical review of ideas/concepts, examination of current policies, awareness of history…

  20. QuizUp Single Player Web

    OpenAIRE

    Gunnar Marteinsson 1983; Kristinn Júlíusson 1993; Sonja Jónsdóttir 1992; Steinar Þór Árnason 1993

    2016-01-01

    In this report we discuss the B.Sc. project named QuizUp Single Player Web. The project was developed at Reykjavik University in the spring of 2016 in collaboration with Plain Vanilla Games, the makers of the world famous QuizUp app. We developed a Single Player Web application based on the original multiplayer game.

  1. Inferring Player Experiences Using Facial Expressions Analysis

    NARCIS (Netherlands)

    Tan, C.T.; Bakkes, S.; Pisan, Y.; Blackmore, K.; Nesbitt, K.; Smith, S.P.

    2014-01-01

    Understanding player experiences is central to game design. Video captures of players is a common practice for obtaining rich reviewable data for analysing these experiences. However, not enough has been done in investigating ways of preprocessing the video for a more efficient analysis process. Thi

  2. Finite stage asymmetric repeated games: Both players' viewpoints

    KAUST Repository

    Li, Lichun

    2017-01-05

    In asymmetric zero-sum games, one player has superior information about the game over the other. It is known that the informed players (maximizer) face the tradeoff of exploiting its superior information at the cost of revealing its superior information, but the basic point of the uninformed player (minimizer)\\'s decision making remains unknown. This paper studies the finite stage asymmetric repeated games from both players\\' viewpoints, and derives that not only security strategies but also the opponents\\' corresponding best responses depends only on the informed player\\'s history action sequences. Moreover, efficient LP formulations to compute both player\\'s security strategies are provided.

  3. Injuries in racket sports among Slovenian players.

    Science.gov (United States)

    Kondric, Miran; Matković, Branka R; Furjan-Mandić, Gordana; Hadzić, Vedran; Dervisević, Edvin

    2011-06-01

    On the sample of 83 top Slovenian athletes we have studied the frequency of injuries among table tennis, tennis and badminton players, types of injuries and severity of injuries--the latter based on data of players absences from training and/or competition processes. The most liable parts to injuries are shoulder girdle (17.27%), spine (16.55%) and ankle (15.83%), while foot (10.07%) and wrist (12.23%) are slightly less liable to injuries. The most frequent injuries in racket sports pertain to muscle tissues. According to this data, the majority of injuries occur halfway through a training session or a competition event, mostly during a competition season. The injuries primarily pertain to muscle tissues; these are followed by joint and tendon injuries. There are no differences between male and female players. Compared to other racket sports players, table tennis players suffer from fewer injuries.

  4. Decreased Nerve Conduction Velocity in Football Players

    Directory of Open Access Journals (Sweden)

    Daryoush Didehdar

    2014-06-01

    Full Text Available Background: Lower limbs nerves are exposed to mechanical injuries in the football players and the purpose of this study is to evaluate the influence of football on the lower leg nerves. Materials and Methods: Nerve conduction studies were done on 35 male college students (20 football players, 15 non active during 2006 to 2007 in the Shiraz rehabilitation faculty. Standard nerve conduction techniques using to evaluate dominant and non dominant lower limb nerves. Results: The motor latency of deep peroneal and tibial nerves of dominant leg of football players and sensory latency of superficial peroneal, tibial and compound nerve action potential of tibial nerve of both leg in football players were significantly prolonged (p<0.05. Motor and sensory nerve conduction velocity of tibial and common peroneal in football players were significant delayed (p<0.05. Conclusion: It is concluded that football is sport with high contact and it causes sub-clinical neuropathies due to nerve entrapment.

  5. Outcomes of microfracture in professional basketball players.

    Science.gov (United States)

    Cerynik, Douglas L; Lewullis, Gabriel E; Joves, Brian C; Palmer, Michael P; Tom, James A

    2009-09-01

    Surgical treatment for chondral defects of the knee in competitive running and jumping athletes remains controversial. This study evaluated the performance outcomes of professional basketball players in the National Basketball Association (NBA) who underwent microfracture. Data from 24 professional basketball players from 1997 to 2006 was obtained and analyzed. NBA player efficiency ratings (PER) were calculated for two seasons before and after injury. A control group of 24 players was used for comparison. Study group and control group demographics including age, NBA experience, and minutes per game demonstrated no statistical difference. Mean time to return to an NBA game was 30.0 weeks from the time of surgery. The first season after returning to competition PER and minutes per game decreased by 3.5 (P 0.05) and 3.0 min (P NBA game. On return to competition player performance and minutes per game are diminished.

  6. Co-option of the piRNA Pathway for Germline-Specific Alternative Splicing of C. elegans TOR

    Directory of Open Access Journals (Sweden)

    Sergio Barberán-Soler

    2014-09-01

    Full Text Available Many eukaryotic genes contain embedded antisense transcripts and repetitive sequences of unknown function. We report that male germline-specific expression of an antisense transcript contained in an intron of C. elegans Target of Rapamycin (TOR, let-363 is associated with (1 accumulation of endo-small interfering RNAs (siRNAs against an embedded Helitron transposon and (2 activation of an alternative 3′ splice site of TOR. The germline-specific Argonaute proteins PRG-1 and CSR-1, which participate in self/nonself RNA recognition, antagonistically regulate the generation of these endo-siRNAs, TOR mRNA levels, and 3′ splice-site selection. Supply of exogenous double-stranded RNA against the region of sense/antisense overlap reverses changes in TOR expression and splicing and suppresses the progressive multigenerational sterility phenotype of prg-1 mutants. We propose that recognition of a “nonself” intronic transposon by endo-siRNAs/the piRNA system provides physiological regulation of expression and alternative splicing of a host gene that, in turn, contributes to the maintenance of germline function across generations.

  7. Executive functioning in highly talented soccer players.

    Science.gov (United States)

    Verburgh, Lot; Scherder, Erik J A; van Lange, Paul A M; Oosterlaan, Jaap

    2014-01-01

    Executive functions might be important for successful performance in sports, particularly in team sports requiring quick anticipation and adaptation to continuously changing situations in the field. The executive functions motor inhibition, attention and visuospatial working memory were examined in highly talented soccer players. Eighty-four highly talented youth soccer players (mean age 11.9), and forty-two age-matched amateur soccer players (mean age 11.8) in the age range 8 to 16 years performed a Stop Signal task (motor inhibition), the Attention Network Test (alerting, orienting, and executive attention) and a visuospatial working memory task. The highly talented soccer players followed the talent development program of the youth academy of a professional soccer club and played at the highest national soccer competition for their age. The amateur soccer players played at a regular soccer club in the same geographical region as the highly talented soccer players and play in a regular regional soccer competition. Group differences were tested using analyses of variance. The highly talented group showed superior motor inhibition as measured by stop signal reaction time (SSRT) on the Stop Signal task and a larger alerting effect on the Attention Network Test, indicating an enhanced ability to attain and maintain an alert state. No group differences were found for orienting and executive attention and visuospatial working memory. A logistic regression model with group (highly talented or amateur) as dependent variable and executive function measures that significantly distinguished between groups as predictors showed that these measures differentiated highly talented soccer players from amateur soccer players with 89% accuracy. Highly talented youth soccer players outperform youth amateur players on suppressing ongoing motor responses and on the ability to attain and maintain an alert state; both may be essential for success in soccer.

  8. Incidence of Stingers in Young Rugby Players.

    Science.gov (United States)

    Kawasaki, Takayuki; Ota, Chihiro; Yoneda, Takeshi; Maki, Nobukazu; Urayama, Shingo; Nagao, Masashi; Nagayama, Masataka; Kaketa, Takefumi; Takazawa, Yuji; Kaneko, Kazuo

    2015-11-01

    A stinger is a type of neurapraxia of the cervical roots or brachial plexus and represents a reversible peripheral nerve injury. The incidence of and major risk factors for stingers among young rugby players remain uninvestigated. To investigate the incidence, symptoms, and intrinsic risk factors for stingers in elite rugby union teams of young players. Descriptive epidemiology study. A total of 569 male rugby players, including 358 players from 7 high school teams and 211 players from 2 university teams, were investigated using self-administered preseason and postseason questionnaires. The prevalence of a history of stingers was 33.9% (95% CI, 30.3-37.9), and 20.9% (119/569) of players experienced at least 1 episode of a stinger during the season (34.2 [95% CI, 26.2-42.1] events per 1000 player-hours of match exposure). The reinjury rate for stingers per season was 37.3% (95% CI, 30.4-44.2). Using the multivariate Poisson regression method, a history of stingers in the previous season and the grade and position of the player were found to be risk factors for stingers during the current season. The mean severity of injury was 2.9 days, with 79.3% (191/241) of the players not losing any time from playing after sustaining a stinger injury and 5.8% (14/241) of the players recovering within more than 14 days. The most frequent symptom was numbness in the unilateral upper extremity, and the most severe symptom was weakness of grasping (mean severity, 6 days). A logistic regression analysis indicated that a history of stingers in the previous season and an injury with more than 3 symptoms, especially motor weakness, were correlated with the severity of injury. Young rugby players with a history of stingers have a significantly high rate of repeat injuries. Although nearly 80% of the players experienced only minimal (0-1 day) time loss injuries, neurological deficits sometimes last beyond 1 month. A history of stingers was identified to be the strongest risk factor for

  9. Examining Player Anger in World of Warcraft

    Science.gov (United States)

    Barnett, Jane; Coulson, Mark; Foreman, Nigel

    This questionnaire study of the sources of anger in World of Warcraft applies classical quantitative measurement scale construction to a new problem, generating a host of questionnaire items that could find use in future studies, and identifying four major categories of events that cause negative effect among players. First, 33 players provided examples of in-game scenarios that had made them angry, and their responses were culled to create a 93-item battery rated by hundreds of player respondents in terms of anger intensity and anger frequency. An iterative process of factor analysis and scale reliability assessment led to a 28-item instrument measuring four anger-provoking factors: Raids/Instances, Griefers, Perceived Time Wasting, and Anti-social Players. These anger-causing scenarios were then illustrated by concrete examples from player and researcher experiences in World of Warcraft. One striking finding is that players become angry at other players' negative behavior, regardless of whether that behavior was intended to harm.

  10. Applied physiology of female soccer players.

    Science.gov (United States)

    Davis, J A; Brewer, J

    1993-09-01

    Women's soccer is in its infancy as a sport and research into its physiological demands and the physical characteristics of players is somewhat limited. There is now an increasing demand for scientific investigation of the female game and of the players, match analysis and role variations requiring particular attention. Current research suggests that the demands of the game for women are similar to those placed on male players. Women are reported to cover a similar distance (mean 8471m) to their male counterparts during a game and much the same proportions of the game appear to be devoted to exercise of varying intensities. Furthermore, female and male players appear to tax the aerobic and anaerobic energy systems to a similar level. The physical and physiological characteristics of female soccer players are comparable with those of other female games players and are more favourable than average for the population. Mean body fat percentages of between 19.7 and 22.0% and VO2max values of between 47.1 and 57.6 ml/kg/min have been reported for elite female players, while faster than average sprint times are also characteristic of them.

  11. Computing Decoupled Residuals for Compact Disc Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2006-01-01

    In order to improve Compact Disc Players playability regarding playing Compact Discs with surface faults, like scratches and fingerprints etc, the attention has been put on fault tolerant control schemes. Almost every of those methods are based on fault detection. The standard approach is to use...... a pair of residuals generated by Compact Disc Player. However, these residuals depend on the performance of position servos in the Compact Disc Player. In other publications of the same authors a pair of decoupled residuals is derived. However, the computation of these alternative residuals has been...

  12. Towards Player-Driven Procedural Content Generation

    DEFF Research Database (Denmark)

    Shaker, Noor; Yannakakis, Georgios N.; Togelius, Julian

    2012-01-01

    Generating immersive game content is one of the ultimate goals for a game designer. This goal can be achieved by realizing the fact that players’ perception of the same game differ according to a number of factors including: players’ personality, playing styles, expertise and culture background....... While one player might find the game immersive, others may quit playing as a result of encountering a seemingly insoluble problem. One promising avenue towards optimizing the gameplay experience for individual game players is to tailor player experience in real-time via automatic game content generation......-driven content generation....

  13. High School Football Players Use Their Helmets to Tackle Other Players Despite Knowing the Risks

    Science.gov (United States)

    Kuriyama, Andrew M; Nakatsuka, Austin S

    2017-01-01

    There is greater attention to head-related injuries and concussions in American football. The helmet's structural safety and the way that football players use their helmets are important in preventing head injuries. Current strategies include penalizing players for high-risk behavior such as leading with their helmet or hitting an opposing player above the shoulder. Passive strategies include helmet modification to better protect the head of the players or to change the playing style of the players. Hawai‘i high school varsity football players were surveyed to determine how they use their helmets and how a new helmet design would affect their style of play. One hundred seventy-seven surveys were completed; 79% said that they used their helmet to hit an opposing player during a tackle and 46% said they made this contact intentionally. When asked about modifying helmets with a soft material on the outside, 48% said they thought putting a soft cover over a regular helmet would protect their head better. However, many participants said that putting a soft cover over their regular helmet was a bad idea for various reasons. Most young football players use their helmets to block or tackle despite being taught they would be penalized or potentially injured if they did so. By gaining a better understanding of why and how players use their helmets and how they would respond to new helmet designs, steps can be taken to reduce head injuries for all levels of play.

  14. Technical player profiles related to the physical fitness of young female volleyball players predict team performance.

    Science.gov (United States)

    Dávila-Romero, C; Hernández-Mocholí, M A; García-Hermoso, A

    2015-03-01

    This study is divided into three sequential stages: identification of fitness and game performance profiles (individual player performance), an assessment of the relationship between these profiles, and an assessment of the relationship between individual player profiles and team performance during play (in championship performance). The overall study sample comprised 525 (19 teams) female volleyball players aged 12-16 years and a subsample (N.=43) used to examine study aims one and two was selected from overall sample. Anthropometric, fitness and individual player performance (actual game) data were collected in the subsample. These data were analyzed through clustering methods, ANOVA and independence chi-square test. Then, we investigated whether the proportion of players with the highest individual player performance profile might predict a team's results in the championship. Cluster analysis identified three volleyball fitness profiles (high, medium, and low) and two individual player performance profiles (high and low). The results showed a relationship between both types of profile (fitness and individual player performance). Then, linear regression revealed a moderate relationship between the number of players with a high volleyball fitness profile and a team's results in the championship (R2=0.23). The current study findings may enable coaches and trainers to manage training programs more efficiently in order to obtain tailor-made training, identify volleyball-specific physical fitness training requirements and reach better results during competitions.

  15. The Cheerleader and the Football Player.

    Science.gov (United States)

    Patil, Malati

    2001-01-01

    Describes an activity in physics using a narrative about a bet between a cheerleader who claims she can lift a 300-pound football player off the ground. Includes questions, teaching notes, and solutions. (MM)

  16. Menstrual cycle disorders in female volleyball players.

    Science.gov (United States)

    Wodarska, M; Witkoś, J; Drosdzol-Cop, A; Dąbrowska, J; Dąbrowska-Galas, M; Hartman, M; Plinta, R; Skrzypulec-Plinta, V

    2013-07-01

    The aim of this study was to examine the relation between increased physical activity and menstrual disorders in adolescent female volleyball players. The study was conducted on 210 Polish female volleyball players, aged 13-17 years, the authorship questionnaire was used. The results of the study showed that irregular menstruation occurred in 19% of girls, spotting between menstrual periods in 27% and heavy menstruation was reported in 33% of girls. Out of all volleyball female players participating in the study, 94 girls (45%) declared absence of menstrual periods after regular cycles. Statistical analysis showed that the more training hours per week, the bigger probability of the occurrence of irregular menstruation. It was concluded that the number of hours of volleyball training per week affects regularity of menstrual cycles in female volleyball players. The absence of menstruation might be caused by the duration of training per week or years of training.

  17. Towards Generic Models of Player Experience

    DEFF Research Database (Denmark)

    Shaker, Noor; Shaker, Mohammad; Abou-Zleikha, Mohamed

    2015-01-01

    further examine whether generic features of player be- haviour can be defined and used to boost the modelling per- formance. The accuracies obtained in both experiments in- dicate a promise for the proposed approach and suggest that game-independent player experience models can be built.......-dependent and their applicability is usually limited to the system and the data used for model construction. Establishing models of user experience that are highly scalable while maintaing the performance constitutes an important research direction. In this paper, we propose generic models of user experience in the computer games...... domain. We employ two datasets collected from players in- teractions with two games from different genres where accu- rate models of players experience were previously built. We take the approach one step further by investigating the mod- elling mechanism ability to generalise over the two datasets. We...

  18. Video Player Keyboard Shortcuts: MedlinePlus

    Science.gov (United States)

    ... page: https://medlineplus.gov/hotkeys.html Video Player Keyboard Shortcuts To use the sharing features on this ... enable JavaScript. MedlinePlus offers a set of accessible keyboard shortcuts for our latest Health videos on the ...

  19. Scouting the Elite, Unbreakable Football Player.

    Science.gov (United States)

    Moore, M

    1981-02-01

    Some NFL football teams see physiological profiling as a means to protect and enhance their competitive and business success. Whether football players will benefit by increased performance and fewer injuries remains to be seen.

  20. Does the Quantum Player Always Win the Classical One?

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hai-Jun; FANG Xi-Ming

    2004-01-01

    @@ We study quantum games in which the players have different strategic spaces. We find that the player who can use a quantum strategic space does not always possess more payoffs than the player who is restricted to apply only classical strategies. We find the condition of the classical player getting more payoffs than the quantum player. We also find that the game exhibits intriguing structures.

  1. RETIRED MATCHES AMONG MALE PROFESSIONAL TENNIS PLAYERS

    Directory of Open Access Journals (Sweden)

    Kristijan Breznik

    2012-06-01

    Full Text Available The aim of this study was to explore the effect of characteristics of various games and players on the proportion of retired tennis matches in the Open Era of tennis. The data included over 420,000 matches played among 17,553 tennis players in the period from 1968 to the end of 2010. The influence of the surface type was clearly confirmed, with the proportion of retired matches being higher on hard and clay courts compared to grass and carpet surfaces. Similarly, more retired matches were observed in outdoor venues than in indoor ones. The impact of other variables, tournament types, rounds at which the game was played and both players' ranks, is more ambiguous. Our interpretation of the obtained results is presented in the paper. Network analytic methods were applied to extract players with the most retired matches in their careers. Eventually, we defined a group of top tennis players and gave a more precise insight into retired matches in that group. Correspondence analysis was used to visually display the two-mode network of top players and the proportion of retired matches by surface type

  2. Cortical thinning in former professional soccer players.

    Science.gov (United States)

    Koerte, Inga K; Mayinger, Michael; Muehlmann, Marc; Kaufmann, David; Lin, Alexander P; Steffinger, Denise; Fisch, Barbara; Rauchmann, Boris-Stephan; Immler, Stefanie; Karch, Susanne; Heinen, Florian R; Ertl-Wagner, Birgit; Reiser, Maximilian; Stern, Robert A; Zafonte, Ross; Shenton, Martha E

    2016-09-01

    Soccer is the most popular sport in the world. Soccer players are at high risk for repetitive subconcussive head impact when heading the ball. Whether this leads to long-term alterations of the brain's structure associated with cognitive decline remains unknown. The aim of this study was to evaluate cortical thickness in former professional soccer players using high-resolution structural MR imaging. Fifteen former male professional soccer players (mean age 49.3 [SD 5.1] years) underwent high-resolution structural 3 T MR imaging, as well as cognitive testing. Fifteen male, age-matched former professional non-contact sport athletes (mean age 49.6 [SD 6.4] years) served as controls. Group analyses of cortical thickness were performed using voxel-based statistics. Soccer players demonstrated greater cortical thinning with increasing age compared to controls in the right inferolateral-parietal, temporal, and occipital cortex. Cortical thinning was associated with lower cognitive performance as well as with estimated exposure to repetitive subconcussive head impact. Neurocognitive evaluation revealed decreased memory performance in the soccer players compared to controls. The association of cortical thinning and decreased cognitive performance, as well as exposure to repetitive subconcussive head impact, further supports the hypothesis that repetitive subconcussive head impact may play a role in early cognitive decline in soccer players. Future studies are needed to elucidate the time course of changes in cortical thickness as well as their association with impaired cognitive function and possible underlying neurodegenerative process.

  3. Morphology of young handball players

    Directory of Open Access Journals (Sweden)

    Adair da Silva Lopes

    2007-06-01

    Full Text Available The purpose of this study was to compare anthropometric and body composition variables from the best male handball athletes competing in the Santa Catarina state youth competition to variables from the other athletes in the same competition, by game position. Seven of the twelve coaches participating in the Santa Catarina Open Youth Games 2004 (up to 18 years freely consented to select the seven best athletes in the competition (one goalkeeper, one pivot, two wingers and three backcourt players. In addition to these seven players, there were a further 79 team members taking part, bringing the total sample size to 86 athletes. The following variables were analyzed: body weight (MC, height (ES, arm span (ENV, hand breadth (DPA, wrist breadth (DRU, forearm circumference (PA, percentage fat (%G, fat mass (MG and lean body mass (MCM. Descriptive statistics (means and standard deviations were employed to classify the athletes according to court position. The chosen athletes were compared with the others using the single-sample t test (p RESUMO Este estudo objetivou comparar variáveis antropométricas e da composição corporal dos melhores atletas de uma competição juvenil (até 18 anos de handebol masculino de Santa Catarina, em relação aos demais atletas da competição por posição de jogo. Sete dentre os doze técnicos participantes dos Joguinhos Abertos de Santa Catarina 2004 aceitaram, voluntariamente, realizar a escolha da seleção dos sete melhores atletas da competição (um goleiro, um pivô, dois extremas e três armadores. Contabilizou-se, além dos sete atletas da seleção, mais 79 atletas titulares de suas equipes, totalizando na amostra, 86 atletas. Foram analisadas as variáveis: massa corporal (MC, estatura (ES, percentual de gordura (%G, massa de gordura (MG, massa corporal magra (MCM, envergadura (ENV, diâmetro palmar (DPA, diâmetro biestilóide rádio-ulnar (DRU e perímetro do antebraço (PA. Utilizou-se a estat

  4. Sports injuries in Plus League volleyball players.

    Science.gov (United States)

    Cieśla, E; Dutkiewicz, R; Mgłosiek, M; Nowak-Starz, G; Markowska, M; Jasiński, P; Dudek, J

    2015-06-01

    Although physical activity brings a range of lifelong health benefits, it may also lead to injuries that pose a significant threat to health. It is particularly noticeable in people involved in professional sports where sport-related injuries commonly occur and are associated with intense exercise which aims to improve physical fitness. The article attempts to determine incidence of sports injuries reported by Plus League volleyball players, as well as to identify their most common types and causes. The research project involved 90 Plus League volleyball players aged 18-37 with the average age of 25.11 (SD±5.378). A method of diagnostic survey was applied to collect empirical data by means of questionnaire developed by the authors (researchers). The results were statistically analysed and verified with the analysis of variance (ANOVA) and χ2 test at the significance level (or critical P-value) of P≤0.05. Over 87% of the respondents suffered from at least one sport-related injury. In total, 362 injuries occurred, on average 4.02 injuries per one volleyball player. The most common sports injuries involved ankle or talocrural joint (46 injuries), knee and lower leg muscles (30), interphalangeal articulations of fingers (30) as well as shoulder joint. More than half of the injuries (57%) occurred twice or three times. Volleyball players commonly sustain injuries through contact with an opposing player in competition. Sport-specific injuries may also occur due to exhaustion, lack of rest and undertreated injuries. The most common volleyball-related injuries are primarily talocrural joint, hand and shoulder injuries. Common types of injuries that can affect volleyball players include muscles, joints and ligaments injuries, sprains and strains as well as bruises. Most of these injuries are caused by exhaustion, contact with an opposing player during competition and fatigue. The incidence of sport-related injuries seems to be influenced by such factors as somatic

  5. Do media players cause interference with pacemakers?

    Science.gov (United States)

    Thaker, Jay P; Patel, Mehul B; Shah, Ashok J; Liepa, Valdis V; Brunett, Joseph D; Jongnarangsin, Krit; Gardiner, Joseph C; Thakur, Ranjan

    2009-11-01

    Electrical devices generate electromagnetic fields that may interfere with pacemakers. Media players cause telemetry interference with pacemakers, but it is not known whether they cause direct interference with pacemakers. The purpose of this study was to examine the interaction between pacemakers and 3 different media players. In this prospective, randomized study, 54 patients with dual chamber pacemakers who were in sinus rhythm underwent baseline observation, followed by observation under telemetry communication. These patients were then randomly evaluated with 3 media players (iPod 3G, iPod Photo, and iPod Touch Apple, Cupertino, CA) with and without telemetry communication for 1 minute each. Patients were monitored for pacemaker malfunction using a single-channel ECG during exposure to media players. The pacemaker was interrogated after each exposure and an interrogation report was printed for evaluation. Pacemaker interference was categorized as type I, II, or III. Types I and II interference described telemetry interference and type III interference was defined as any direct interference with pacemaker function or programmed parameters. A total of 54 patients (29 men and 25 women; mean age 77.2 +/- 9.3 y) were evaluated. In total, of the 162 tests (for telemetry interference) 36.4% were positive (Type I and II). Type III interference was also evaluated in 162 tests and none showed any evidence of direct interference. Media players cause telemetry interference with pacemakers, but they do not directly interfere with pacemaker function.

  6. Game Performance Evaluation in Male Goalball Players

    Directory of Open Access Journals (Sweden)

    Molik Bartosz

    2015-12-01

    Full Text Available Goalball is a Paralympic sport exclusively for athletes who are visually impaired and blind. The aims of this study were twofold: to describe game performance of elite male goalball players based upon the degree of visual impairment, and to determine if game performance was related to anthropometric characteristics of elite male goalball players. The study sample consisted of 44 male goalball athletes. A total of 38 games were recorded during the Summer Paralympic Games in London 2012. Observations were reported using the Game Efficiency Sheet for Goalball. Additional anthropometric measurements included body mass (kg, body height (cm, the arm span (cm and length of the body in the defensive position (cm. The results differentiating both groups showed that the players with total blindness obtained higher means than the players with visual impairment for game indicators such as the sum of defense (p = 0.03 and the sum of good defense (p = 0.04. The players with visual impairment obtained higher results than those with total blindness for attack efficiency (p = 0.04, the sum of penalty defenses (p = 0.01, and fouls (p = 0.01. The study showed that athletes with blindness demonstrated higher game performance in defence. However, athletes with visual impairment presented higher efficiency in offensive actions. The analyses confirmed that body mass, body height, the arm span and length of the body in the defensive position did not differentiate players’ performance at the elite level.

  7. On uniform exponential growth for solvable groups

    OpenAIRE

    Breuillard, Emmanuel

    2006-01-01

    Using a theorem of J. Groves we give a ping-pong proof of Osin's uniform exponential growth for solvable groups. We discuss slow exponential growth and show that this phenomenon disappears as one passes to a finite index subgroup.

  8. Motivation and Sport Injuries in Handball Players

    Directory of Open Access Journals (Sweden)

    Laguna, María

    2010-12-01

    Full Text Available The aim of the study was to test whether different levels of motivation are related to the injuries suffered by elite athletes. The sample consists of 80 professional handball players of ASOBAL League, with a mean age of 24.83 years (+ 5.21. Motivation was assessed through the CPRD scale (Gimeno, Buceta & Pérez-Llantada; 1999 and a self-report questionnaire was used to register sports injuries. The results indicate that there is a relationship between motivational levels and the risk for injury. Specifically, players with high motivated players had a greater number of moderate injuries. Although it may seem paradoxical, it is possible that an excessively high motivation leads to overachievement and risk behaviors, which in turn facilitate the appearance of lesions.

  9. Cricket club looking for new players

    CERN Multimedia

    Cricket Club

    2016-01-01

    The CERN Cricket Club, having lost several key players, has had a very difficult season so far and is desperately in need of new players. Having qualified for the Cricket Switzerland semi-finals for the last two years (unfortunately losing both), this year we are bottom of the Western Pool, having played the last two league matches with only 10 players. If you are interested in playing cricket please join us at net practice, which takes place on the Prevessin site each Thursday evening from 18:00 to around 20:00 (weather permitting) or send me an e-mail (see below). Please have a look at the Cricket Club web site for more information: http://cern.ch/Club-Cricket/ Chris Onions, President of the CERN Cricket Club   (christopher.onions@gmail.com)

  10. Big Data for Business Ecosystem Players

    Directory of Open Access Journals (Sweden)

    Perko Igor

    2016-06-01

    Full Text Available In the provided research, some of the Big Data most prospective usage domains connect with distinguished player groups found in the business ecosystem. Literature analysis is used to identify the state of the art of Big Data related research in the major domains of its use-namely, individual marketing, health treatment, work opportunities, financial services, and security enforcement. System theory was used to identify business ecosystem major player types disrupted by Big Data: individuals, small and mid-sized enterprises, large organizations, information providers, and regulators. Relationships between the domains and players were explained through new Big Data opportunities and threats and by players’ responsive strategies. System dynamics was used to visualize relationships in the provided model.

  11. Adapting virtual camera behaviour through player modelling

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2015-01-01

    Research in virtual camera control has focused primarily on finding methods to allow designers to place cameras effectively and efficiently in dynamic and unpredictable environments, and to generate complex and dynamic plans for cinematography in virtual environments. In this article, we propose...... a novel approach to virtual camera control, which builds upon camera control and player modelling to provide the user with an adaptive point-of-view. To achieve this goal, we propose a methodology to model the player’s preferences on virtual camera movements and we employ the resulting models to tailor...... the viewpoint movements to the player type and her game-play style. Ultimately, the methodology is applied to a 3D platform game and is evaluated through a controlled experiment; the results suggest that the resulting adaptive cinematographic experience is favoured by some player types and it can generate...

  12. Mean Field Games with a Dominating Player

    Energy Technology Data Exchange (ETDEWEB)

    Bensoussan, A., E-mail: axb046100@utdallas.edu [The University of Texas at Dallas, International Center for Decision and Risk Analysis, Jindal School of Management (United States); Chau, M. H. M., E-mail: michaelchaumanho@gmail.com; Yam, S. C. P., E-mail: scpyam@sta.cuhk.edu.hk [The Chinese University of Hong Kong, Department of Statistics (Hong Kong, People’s Republic of China) (China)

    2016-08-15

    In this article, we consider mean field games between a dominating player and a group of representative agents, each of which acts similarly and also interacts with each other through a mean field term being substantially influenced by the dominating player. We first provide the general theory and discuss the necessary condition for the optimal controls and equilibrium condition by adopting adjoint equation approach. We then present a special case in the context of linear-quadratic framework, in which a necessary and sufficient condition can be asserted by stochastic maximum principle; we finally establish the sufficient condition that guarantees the unique existence of the equilibrium control. The proof of the convergence result of finite player game to mean field counterpart is provided in Appendix.

  13. There is no game without a player

    DEFF Research Database (Denmark)

    Larsen, Lasse Juel

    on the subject matter from the catalogue of game theory. All four suggestions exclude the player from the relationship. This paper introduces a phenomenological point of view and includes the player in order to understand the relationship between structure and dressing. It argues that players constitute a bridge......This paper is a search for meaning or to be more precise a study of how meaning is produced between ontology and fiction in computer games. It sets out to investigate the relationship between formal abstract game structures and game representation (dressing) by presenting four suggestions...... or the center which establishes, upholds and renegotiate the relationship between formal game structure and game dressing. It also argues that players’ interaction with both structure and dressing produce meaning and the production of meaning is the relationship between formal abstract game structures and game...

  14. Modelling Virtual Camera Behaviour Through Player Gaze

    DEFF Research Database (Denmark)

    Picardi, Andrea; Burelli, Paolo; Yannakakis, Georgios N.

    2012-01-01

    In a three-dimensional virtual environment, aspects such as narrative and interaction largely depend on the placement and animation of the virtual camera. Therefore, virtual camera control plays a critical role in player experience and, thereby, in the overall quality of a computer game. Both game...... industry and game AI research focus on the devel- opment of increasingly sophisticated systems to automate the control of the virtual camera integrating artificial intel- ligence algorithms within physical simulations. However, in both industry and academia little research has been carried out...... on the relationship between virtual camera, game-play and player behaviour. We run a game user experiment to shed some light on this relationship and identify relevant dif- ferences between camera behaviours through different game sessions, playing behaviours and player gaze patterns. Re- sults show that users can...

  15. Individual recovery profiles in basketball players.

    Science.gov (United States)

    Moreno, Jordi; Ramos-Castro, Juan; Rodas, Gil; Tarragó, Joan R; Capdevila, Lluís

    2015-01-01

    In the sport context, recovery has been characterized as a multifactor process (physiological, psychological, behavioral, social, etc.). This study takes a multidisciplinary approach to find psychophysiological markers of the stress-recovery process. It aims to determine how athletes' specific recovery actions relate to their perceptions of recovery, and Heart Rate Variability (HRV). A total of 196 assessments were analyzed from 6 players on a men's professional basketball team within the Liga LEB Oro basketball federation (2012/2013 season). Perceptions of recovery, recovery strategies, and HRV were recorded. The results show a pattern of individual differences in behavior related to athletes' recovery actions and HRV profiles throughout the season (p < .05). Moreover, we observed that each player had different recovery needs. In light of these results, we suggest an individualistic approach to evaluating and monitoring recovery to attend more accurately to each player's recovery needs.

  16. Cervical joint position sense in rugby players versus non-rugby players.

    Science.gov (United States)

    Pinsault, Nicolas; Anxionnaz, Marion; Vuillerme, Nicolas

    2010-05-01

    To determine whether cervical joint position sense is modified by intensive rugby practice. A group-comparison study. University Medical Bioengineering Laboratory. Twenty young elite rugby players (10 forwards and 10 backs) and 10 young non-rugby elite sports players. Participants were asked to perform the cervicocephalic relocation test (CRT) to the neutral head position (NHP) that is, to reposition their head on their trunk, as accurately as possible, after full active left and right cervical rotation. Rugby players were asked to perform the CRT to NHP before and after a training session. Absolute and variable errors were used to assess accuracy and consistency of the repositioning for the three groups of Forwards, Backs and Non-rugby players, respectively. The 2 groups of Forwards and Backs exhibited higher absolute and variable errors than the group of Non-rugby players. No difference was found between the two groups of Forwards and Backs and no difference was found between Before and After the training session. The cervical joint position sense of young elite rugby players is altered compared to that of non-rugby players. Furthermore, Forwards and Backs demonstrated comparable repositioning errors before and after a specific training session, suggesting that cervical proprioceptive alteration is mainly due to tackling and not the scrum.

  17. Injury incidence and balance in rugby players.

    Science.gov (United States)

    M, Jaco Ras; Puckree, Threethambal

    2014-01-01

    Objective : This study determined and correlated injury incidence and balance in rugby players. A prospective survey with balance testing was conducted on first year rugby academy players (N= 114). Injury incidence, static and dynamic balance were tested pre and post-season using a Biosway portable balance system. The data was analysed using paired and independent samples t-tests at pscrum-half (14.80%) playing position, injuries in the 2nd half of the match (57%), and during contact (67%). Conclusion : Injury incidence was related to static and dynamic balance in forward right direction only.

  18. Fault Predictive Control of Compact Disk Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Wickerhauser, Mladen Victor

    2006-01-01

    Optical disc players such as CD-players have problems playing certain discs with surface faults like scratches and fingerprints. The problem is to be found in the servo controller which positions the optical pick-up, such that the laser beam is focused on the information track. A scheme handling ...... of the feature based control scheme, such that a prediction step is included. The proposed scheme is compared with the feature based control scheme, in the perspective of handling surface faults, by simulations. These simulations show the improvements given by the proposed algorithm....

  19. Sprint, agility, strength and endurance capacity in wheelchair basketball players

    National Research Council Canada - National Science Library

    Yanci, J; Granados, C; Otero, M; Badiola, A; Olasagasti, J; Bidaurrazaga-Letona, I; Iturricastillo, A; Gil, Sm

    ...; and secondly, to analyse the physical characteristics measured by sprint, agility, strength and endurance field tests in wheelchair basketball (WB) players. 16 WB players (33.06 ± 7.36 years, 71.89...

  20. Jet Lag a Drag on Pro Baseball Players

    Science.gov (United States)

    ... 163187.html Jet Lag a Drag on Pro Baseball Players Study found traveling across time zones linked ... might be more than just tiring for pro baseball players: The resulting jet lag may actually harm ...

  1. Training Patterns of Wheelchair Basketball Players in Turkey

    Science.gov (United States)

    Tatar, Yasar

    2008-01-01

    The aim of this study was to analyze technical drills, warm-up and cool-down exercises used by wheelchair basketball players of the Turkish league in relation to training sessions. 33 male wheelchair basketball players participated in the study (mean age 26.6[plus or minus]5,95 years). All players reported that they used warm-up exercises before…

  2. Automatic player detection and identification for sports entertainment applications

    NARCIS (Netherlands)

    Mahmood, Zahid; Ali, Tauseef; Khattak, Shadid; Hasan, Laiq; Khan, Samee U.

    2014-01-01

    In this paper, we develop an augmented reality sports broadcasting application for automatic detection, recognition of players during play, followed by display of personal information of players. The proposed application can be divided into four major steps. In first step, each player in the image i

  3. Synthetic Players: A Quest for Artificial Intelligence in Computer Games

    Directory of Open Access Journals (Sweden)

    Jouni Smed

    2005-03-01

    Full Text Available Synthetic players are the computer-controlled actors in a computer game. In this paper, we describe both the implementation issues and the behavioural expectations related to synthetic players. We recognize the role of synthetic players by analysing the components of games in general and computer games in particular.

  4. Assessment of Cardiovascular Risk in Collegiate Football Players and Nonathletes

    Science.gov (United States)

    Dobrosielski, Devon A.; Rosenbaum, Daryl; Wooster, Benjamin M.; Merrill, Michael; Swanson, John; Moore, J. Brian; Brubaker, Peter H.

    2010-01-01

    Collegiate American football players may be at risk for cardiovascular disease. Objective: To compare cardiovascular disease risk factors and cardiovascular structure and function parameters of football players, stratified by position, to a group of sedentary, nonathletes. Participants: Twenty-six collegiate football players and 13 nonathletes…

  5. Assessment of Cardiovascular Risk in Collegiate Football Players and Nonathletes

    Science.gov (United States)

    Dobrosielski, Devon A.; Rosenbaum, Daryl; Wooster, Benjamin M.; Merrill, Michael; Swanson, John; Moore, J. Brian; Brubaker, Peter H.

    2010-01-01

    Collegiate American football players may be at risk for cardiovascular disease. Objective: To compare cardiovascular disease risk factors and cardiovascular structure and function parameters of football players, stratified by position, to a group of sedentary, nonathletes. Participants: Twenty-six collegiate football players and 13 nonathletes…

  6. Understanding the Mismatch Between Coaches' and Players' Perceptions of Exertion

    NARCIS (Netherlands)

    Brink, Michel S.; Kersten, Anna W.; Frencken, Wouter G. P.

    2017-01-01

    A mismatch between the training exertion intended by a coach and the exertion perceived by players is well established in sports. However, it is unknown whether coaches can accurately observe exertion of individual players during training. Furthermore, the discrepancy in coaches' and players' percep

  7. High School Rugby Players' Perception of Coaching Effectiveness

    Science.gov (United States)

    Broodryk, Retief; van den Berg, Pieter Hendrick

    2011-01-01

    The aims of this study were firstly to determine the players' perceptions of their respective coaches' coaching effectiveness and secondly, determine the difference between big and small schools of the players' perceptions of their respective coaches' coaching effectiveness. Four hundred and seventy six players from 22 schools were asked to fill…

  8. Preferred Leadership Behaviours of Male and Female Badminton Players

    OpenAIRE

    Rajkumar S HARMA

    2015-01-01

    Pr eferences for specific coaching behaviours of male and female Badminton players were measured by the modified and revised Leadership Scale for Sport. Eighty two (Males=61, Females=21) badminton players were selected from amongst the players representing th eir respective university teams in East - zone Inter - university Badminton (Men/Women) tournaments held at Bilaspur (CG). The present investigation noted ...

  9. Automatic player detection and identification for sports entertainment applications

    NARCIS (Netherlands)

    Mahmood, Zahid; Ali, Tauseef; Khattak, Shadid; Hasan, Laiq; Khan, Samee U.

    In this paper, we develop an augmented reality sports broadcasting application for automatic detection, recognition of players during play, followed by display of personal information of players. The proposed application can be divided into four major steps. In first step, each player in the image

  10. Dynamic Difficulty Balancing for Cautious Players and Risk Takers

    Directory of Open Access Journals (Sweden)

    Guy Hawkins

    2012-01-01

    Full Text Available Dynamic balancing of game difficulty can help cater for different levels of ability in players. However, performance in some game tasks depends on not only the player's ability but also their desire to take risk. Taking or avoiding risk can offer players its own reward in a game situation. Furthermore, a game designer may want to adjust the mechanics differently for a risky, high ability player, as opposed to a risky, low ability player. In this work, we describe a novel modelling technique known as particle filtering which can be used to model various levels of player ability while also considering the player's risk profile. We demonstrate this technique by developing a game challenge where players are required to make a decision between a number of possible alternatives where only a single alternative is correct. Risky players respond faster but with more likelihood of failure. Cautious players wait longer for more evidence, increasing their likelihood of success, but at the expense of game time. By gathering empirical data for the player's response time and accuracy, we develop particle filter models. These models can then be used in real-time to categorise players into different ability and risk-taking levels.

  11. Understanding the Mismatch Between Coaches' and Players' Perceptions of Exertion

    NARCIS (Netherlands)

    Brink, Michel S; Kersten, Anna W; Frencken, Wouter G

    2016-01-01

    A mismatch between the intended training exertion by the coach and the perceived exertion by players is well established in sports. However, it is unknown if coaches are able to accurately observe exertion of individual players during training. Furthermore, the discrepancy in coaches' and players' p

  12. Kinanthropometric characteristics in teenager basketball players

    Directory of Open Access Journals (Sweden)

    Maria Abella del Campo

    2015-12-01

    Full Text Available Introduction: Basketball is a sport with a high heterogeneity anthropometric as playing position. Point guard is usually the lowest player but also the fastest. Guard is similar to point guard, faster and more agile than the others. Small forward has an intermediate height between the inside and outside players and it combines height with velocity. And center (pivot has a physical role, it has the highest and more muscle mass. The aim of this study is to describe the kinanthropometric profile of male cadet “Valencia Basket Club”. Material and Methods: A total of 20 male cadet basketball players were evaluated (15.35±0.59 years old. An anthropometrist level 1 took anthropometric measures according to the methodology of the International Society for the Advancement of Kinanthropometry (ISAK. Body composition was calculated according to the kinanthropometry consensus of the Kinanthropometry Spanish Group (GREC, somatotype with Heath-Carter’s method and adiposemuscular and cardiovascular risk index. Results: Differences in values of weight, height, skinfold and body composition from variables of sample and position were observed. Lower values were from point guard position and higher values were from center position. An increasing trend of these parameters was established in the following order: point guard, guard, small forward and center. Conclusions: The Valencia Basket Club cadet player overall somatotype is balance ectomorph. To know kinanthropometric profile may be beneficial to develop specific training and nutrition plans as well as to see evolution and characteristics for optimal performance

  13. Soccer skill development in talented players.

    Science.gov (United States)

    Huijgen, B C H; Elferink-Gemser, M T; Ali, A; Visscher, C

    2013-08-01

    The aim of the study was to gain insight into the development of soccer-specific skills and whether differences between talented players exist on the Loughborough Soccer Passing Test (LSPT). Two scores were derived from the LSPT: 1) execution time: time to complete 16 passes (speed) and 2) skill performance time: execution time including bonus and penalty time for accuracy. The study consisted of 2 parts, the first of which incorporated a quasi-longitudinal design with 270 talented players aged 10-18 years performing the LSPT (661 measurement occasions); multilevel modelling was applied. Secondly, differences between those players allowed to continue in the development program (selected, n=269) and players who were forced to leave (de-selected, n=50) were investigated using independent sample t-tests. The longitudinal data showed that the predicted execution time (i. e., speed) improved approximately 18% from age 10-18 years (Pskill performance time (i. e., combination of speed and accuracy) was predicted to improve approximately 32% (Pskill performance time (P0.05). In conclusion, in high-level youth soccer, the combination of speed and accuracy in soccer skills might be more important than speed alone. © Georg Thieme Verlag KG Stuttgart · New York.

  14. Mental rotation performance in male soccer players.

    Directory of Open Access Journals (Sweden)

    Petra Jansen

    Full Text Available It is the main goal of this study to investigate the visual-spatial cognition in male soccer players. Forty males (20 soccer players and 20 non-athletes solved a chronometric mental rotation task with both cubed and embodied figures (human figures, body postures. The results confirm previous results that all participants had a lower mental rotation speed for cube figures compared to embodied figures and a higher error rate for cube figures, but only at angular disparities greater than 90°. It is a new finding that soccer-players showed a faster reaction time for embodied stimuli. Because rotation speed did not differ between soccer-players and non-athletes this finding cannot be attributed to the mental rotation process itself but instead to differences in one of the following processes which are involved in a mental rotation task: the encoding process, the maintanence of readiness, or the motor process. The results are discussed against the background of the influence on longterm physical activity on mental rotation and the context of embodied cognition.

  15. Motivational Traits of Elite Young Soccer Players

    Science.gov (United States)

    Stewart, Craig; Meyers, Michael C.

    2004-01-01

    Among the most overlooked aspects in the development of elite young soccer players is that of specific psychological traits. Of those traits, motivation has important implications for programs whose objectives are identification and cultivation of young, skilled performers. The growth in popularity of soccer by youth and the successes experienced…

  16. Soccer Skill Development in Talented Players

    NARCIS (Netherlands)

    Huijgen, B. C. H.; Elferink-Gemser, M. T.; Ali, A.; Visscher, C.

    2013-01-01

    The aim of the study was to gain insight into the development of soccer-specific skills and whether differences between talented players exist on the Loughborough Soccer Passing Test (LSPT). Two scores were derived from the LSPT: 1) execution time: time to complete 16 passes (speed) and 2) skill per

  17. Football players, asset management & the unexploited potential of enhanced player engagement in football management & marketing

    DEFF Research Database (Denmark)

    Cortsen, Kenneth

    2014-01-01

    This article gives insights into why and how football brands (e.g. clubs and governing bodies) can benefit from enhancing the activation of players in football management and football marketing initiatives.......This article gives insights into why and how football brands (e.g. clubs and governing bodies) can benefit from enhancing the activation of players in football management and football marketing initiatives....

  18. Football players, asset management & the unexploited potential of enhanced player engagement in football management & marketing

    DEFF Research Database (Denmark)

    Cortsen, Kenneth

    2016-01-01

    This article gives insights into why and how football brands (e.g. clubs and governing bodies) can benefit from enhancing the activation of players in football management and football marketing initiatives.......This article gives insights into why and how football brands (e.g. clubs and governing bodies) can benefit from enhancing the activation of players in football management and football marketing initiatives....

  19. Anthropometric Characteristics of Spanish Professional Basketball Players

    Directory of Open Access Journals (Sweden)

    Vaquera Alejandro

    2015-06-01

    Full Text Available The study of elite basketball players’ anthropometric characteristics alongside those of body composition contributes significantly to their profiling as professional athletes and plays an important role in the selection process, as these characteristics can have a significant impact on performance. In the current study, 110 professional basketball players from a series of Spanish professional Leagues (ACB, LEB and EBA and youth level National Teams (U20 and U18 had their anthropometric profiles measured and compared to determine differences between them. Furthermore, all 110 players were divided into three different categories according to their playing position: guards, forwards and centres. The results obtained show no significant differences between players in different competitions in weight, height and the sum of skinfolds. Nonetheless, there were several differences related to body fat content (13.03% in ACB players and 10.52% in the lower categories and National Teams. There were also several differences found between the different playing positions amongst all playing levels in body mass (79.56 ± 2.41, 91.04 ± 1.51 and 104.56 ± 1.73 kg, height (182.28 ± 0.96, 195.65 ± 1.00 and 204.08 ± 0.67 cm, skinfold distribution and perimeters. However, there were no significant differences in body fat content between the different playing positions. The conclusions obtained from this study provide a better understanding to basketball specialists regarding the selection process of players at the elite level, especially on the transition from youth elite programs to men’s elite leagues.

  20. The architecture of the chess player's brain.

    Science.gov (United States)

    Hänggi, Jürgen; Brütsch, Karin; Siegel, Adrian M; Jäncke, Lutz

    2014-09-01

    The game of chess can be seen as a typical example for an expertise task requiring domain-specific training and experience. Despite intensive behavioural studies the neural underpinnings of chess performance and expertise are not entirely understood. A few functional neuroimaging studies have shown that expert chess players recruit different psychological functions and activate different brain areas while they are engaged in chess-related activities. Based on this functional literature, we predicted to find morphological differences in a network comprised by parietal and frontal areas and especially the occipito-temporal junction (OTJ), fusiform gyrus, and caudate nucleus. Twenty expert chess players and 20 control subjects were investigated using voxel-based and surface-based morphometry as well as diffusion tensor imaging. Grey matter volume and cortical thickness were reduced in chess players compared with those of control men in the OTJ and precunei. The volumes of both caudate nuclei were not different between groups, but correlated inversely with the years of chess playing experience. Mean diffusivity was increased in chess players compared with that of controls in the left superior longitudinal fasciculus and the Elo score (a chess tournament ranking) was inversely related to mean diffusivity within the right superior longitudinal fasciculus. To the best of our knowledge we showed for the first time that there are specific differences in grey and white matter morphology between chess players and control subjects in brain regions associated with cognitive functions important for playing chess. Whether these anatomical alterations are the cause or consequence of the intensive and long-term chess training and practice remains to be shown in future studies.

  1. Dynamic Visual Acuity Training in Cricket Players

    Directory of Open Access Journals (Sweden)

    Renee Edgar, B.Optom

    2015-04-01

    Full Text Available Background: Dynamic visual acuity (DVA is the ability of an observer to correctly identify details of a moving target and is considered to be important for tasks like driving. Dynamic Visual Acuity is better in athletes involved in sports such as basketball and baseball; however, no previous studies have considered the sport of cricket. We conducted a study to determine whether there was any difference in DVA between cricket and non-cricket players. Method: Dynamic visual acuity was measured by asking subjects to identify the orientation of the gap of a moving Landolt C target as a four-alternative forced-choice task. The Landolt C targets had confusion bars surrounding them. The participants in the study were tested twice with a break of seven weeks. In between the two measurements, participants underwent two training sessions (similar to the testing sessions, each three weeks apart. Results: The initial mean DVA for cricket players was 107.7 deg/sec, and the mean DVA for non-cricket players was 105.5 deg/sec, with a target size of 6/15. The subjects who participated in training (cricketers and non-cricketers improved in DVA by 41 deg/sec in contrast to the improvement in the non-training subjects of 18 deg/sec (p=0.0032. The cricketers who participated in the training improved in DVA by 44 deg/sec, whereas the cricketers who did not participate in the training improved by 19 deg/sec (p=0.0167. Conclusions: We found no significant difference in initial DVA between the cricket players and the non-cricket players. The training resulted in an extremely significant improvement in DVA performance by both the cricketers and non-cricketers.

  2. Evaluating Australian football league player contributions using interactive network simulation.

    Science.gov (United States)

    Sargent, Jonathan; Bedford, Anthony

    2013-01-01

    This paper focuses on the contribution of Australian Football League (AFL) players to their team's on-field network by simulating player interactions within a chosen team list and estimating the net effect on final score margin. A Visual Basic computer program was written, firstly, to isolate the effective interactions between players from a particular team in all 2011 season matches and, secondly, to generate a symmetric interaction matrix for each match. Negative binomial distributions were fitted to each player pairing in the Geelong Football Club for the 2011 season, enabling an interactive match simulation model given the 22 chosen players. Dynamic player ratings were calculated from the simulated network using eigenvector centrality, a method that recognises and rewards interactions with more prominent players in the team network. The centrality ratings were recorded after every network simulation and then applied in final score margin predictions so that each player's match contribution-and, hence, an optimal team-could be estimated. The paper ultimately demonstrates that the presence of highly rated players, such as Geelong's Jimmy Bartel, provides the most utility within a simulated team network. It is anticipated that these findings will facilitate optimal AFL team selection and player substitutions, which are key areas of interest to coaches. Network simulations are also attractive for use within betting markets, specifically to provide information on the likelihood of a chosen AFL team list "covering the line ". Key pointsA simulated interaction matrix for Australian Rules football players is proposedThe simulations were carried out by fitting unique negative binomial distributions to each player pairing in a sideEigenvector centrality was calculated for each player in a simulated matrix, then for the teamThe team centrality measure adequately predicted the team's winning marginA player's net effect on margin could hence be estimated by replacing him in

  3. Multi-Player and Multi-Choice Quantum Game

    Institute of Scientific and Technical Information of China (English)

    杜江峰; 李卉; 许晓栋; 周先意; 韩荣典

    2002-01-01

    We investigate a multi-player and multi-choice quantum game. We start from a two-player and two-choice game,and the result is better than its classical version. Then we extend this to N-player and N-choice cases. In the quantum domain, we provide a strategy with which players can always avoid the worst outcome. Also, by changing the value of the parameter of the initial state, the probabilities for players to obtain the best pay-off will be much higher than in its classical version.

  4. MiRNAs and piRNAs from bone marrow mesenchymal stem cell extracellular vesicles induce cell survival and inhibit cell differentiation of cord blood hematopoietic stem cells: a new insight in transplantation.

    Science.gov (United States)

    De Luca, Luciana; Trino, Stefania; Laurenzana, Ilaria; Simeon, Vittorio; Calice, Giovanni; Raimondo, Stefania; Podestà, Marina; Santodirocco, Michele; Di Mauro, Lazzaro; La Rocca, Francesco; Caivano, Antonella; Morano, Annalisa; Frassoni, Francesco; Cilloni, Daniela; Del Vecchio, Luigi; Musto, Pellegrino

    2016-02-01

    Hematopoietic stem cells (HSC), including umbilical cord blood CD34+ stem cells (UCB-CD34+), are used for the treatment of several diseases. Although different studies suggest that bone marrow mesenchymal stem cells (BM-MSC) support hematopoiesis, the exact mechanism remains unclear. Recently, extracellular vesicles (EVs) have been described as a novel avenue of cell communication, which may mediate BM-MSC effect on HSC. In this work, we studied the interaction between UCB-CD34+ cells and BM-MSC derived EVs. First, by sequencing EV derived miRNAs and piRNAs we found that EVs contain RNAs able to influence UCB-CD34+ cell fate. Accordingly, a gene expression profile of UCB-CD34+ cells treated with EVs, identified about 100 down-regulated genes among those targeted by EV-derived miRNAs and piRNAs (e.g. miR-27b/MPL, miR-21/ANXA1, miR-181/EGR2), indicating that EV content was able to modify gene expression profile of receiving cells. Moreover, we demonstrated that UCB-CD34+ cells, exposed to EVs, significantly changed different biological functions, becoming more viable and less differentiated. UCB-CD34+ gene expression profile also identified 103 up-regulated genes, most of them codifying for chemokines, cytokines and their receptors, involved in chemotaxis of different BM cells, an essential function of hematopoietic reconstitution. Finally, the exposure of UCB-CD34+ cells to EVs caused an increased expression CXCR4, paralleled by an in vivo augmented migration from peripheral blood to BM niche in NSG mice. This study demonstrates the existence of a powerful cross talk between BM-MSC and UCB-CD34+ cells, mediated by EVs, providing new insight in the biology of cord blood transplantation.

  5. Prospective study of injury in volleyball players: 6 year results.

    Science.gov (United States)

    Pastor, M F; Ezechieli, M; Classen, L; Kieffer, O; Miltner, O

    2015-01-01

    The volleyball game has a high complexity and thus entails a lot of strain to the players. Due to this high and different training and competition strain comprehensive and individual training plans should be developed with competing training objectives in order to prevent injuries. The aim of the study was to analyse prospectively over six seasons the acute and overuse injuries of a German male professional volleyball team. The study included 34 male national league players from season the 2007/08 to 2012/13. All players received a sport medicine examination and a functional diagnosis before each season. Based on the results the players received an individual training plan. The players suffered 186 injuries. The prevalence of acute injuries was 1.94 per player and overuse injuries 0.64 per player. The incidence of acute injuries was 3.3/1000 h volleyball and overuse injuries 1.08/1000 h volleyball. The largest number of injuries was found in the spine. The players had most likely minor injuries. The players had significantly fewer injuries in their second season (1.92) than in their first season (3.25; p= 0.004). It could be concluded that volleyball is a sport with a relative low prevalence of injuries compared to other team sports. The prevalence of injury is 2.58 per player. Due to an injury a player dropped out 16.91 days per season. An individual training program seems to reduce the incidence of injury.

  6. Recognition accuracy by experienced men and women players of basketball.

    Science.gov (United States)

    Millslagle, Duane G

    2002-08-01

    This study examined 30 experienced basketball players' recognition accuracy by sex, playing position (guard, forward, and center), and situations in the game of basketball. The study used a perceptual cognitive paradigm in which subjects viewed slides of structured and unstructured game situations and accurately recognized the presence or absence of the basketball. A significant difference in recognition accuracy by sex, players' position, and structure of the game situation was found. Male players' recognition accuracy was better than the female players'. The recognition accuracy of subjects who played guard was better than that of subjects who played forward or center. The players' recognition accuracy was more accurate when observing structured plays versus unstructured plays. The conclusion of this study suggested that experienced basketball players differ in their cognitive and visual searching processes by sex and player position within the sport of basketball.

  7. Identification af explosive power factors as predictors of player quality in young female volleyball players.

    Science.gov (United States)

    Grgantov, Zoran; Milić, Mirjana; Katić, Ratko

    2013-05-01

    With the purpose of determining the factor structure of explosive power, as well as the influence of each factor on situational efficiency, 56 young female volleyball players were tested using 14 tests for assessing nonspecific and specific explosive power. By factor analysis, 4 significant factors were isolated which explained the total of over 80% of the common variability in young female volleyball players. The first factor was defined as volleyball-specific jumping, the second factor as nonspecific jumping and sprinting, the third factor as throwing explosive power, while the fourth factor was interpreted as volleyball-specific throwing and spiking speed from the ground. Results obtained by regression analysis in the latent space of explosive power indicate that the identified factors are good predictors of player quality in young female volleyball players. The fourth factor defined as throwing and spiking speed from the ground had the largest influence on player quality, followed by volleyball-specific jumping and nonspecific jumping and sprinting, and to a much lesser extent, by throwing explosive power The results obtained in this age group bring to the fore the ability of spiking and serving a ball of high speed, which hinders the opponents from playing those balls in serve reception and field defence. This ability, combined with a high standing vertical jump reach and spike approach vertical jump reach (which is the basis of the 1st varimax factor) enables successful performance of all volleyball elements by which points are won in complex 1 (spike) and complex 2 (serve and block). Even though the 2nd factor (nonspecific jumping and sprinting) has a slightly smaller impact on situational efficiency in young players, this ability provides preconditions i.e. preparation for successful realisation of all volleyball elements, so greater attention must be paid to perfecting it in young female volleyball players.

  8. Player Transformation of Educational Multiplayer Games

    DEFF Research Database (Denmark)

    Magnussen, Rikke; Misfeldt, Morten

    2004-01-01

    Children's great interest in multiplayer games has led to attempts to design educational multiplayer games. In this study, we have studied a test of an educational multiplayer game designed for mathematics education for children aged nine to twelve. In our observations, it became clear that pupils...... transformed the game to accommodate social interaction. With these transformed ways of playing the game, they managed to get to the top of the high score list while avoiding the educational parts of the game. Players transforming educational games to escape learning elements can be a problem when these games...... are used for formal education. In this paper we argue that player transformation of educational games can, however, be the basis of exciting and unconventional learning of valuable things, such as how to transform information technology to better accommodate social interaction....

  9. Common Injuries of Collegiate Tennis Players

    Directory of Open Access Journals (Sweden)

    Christian Wisdom Magtajas Valleser

    2017-09-01

    Full Text Available The purpose of this study is to determine the common injuries of Filipino collegiate tennis players; 110 varsity tennis players with a mean of 20 years old (SD ± 1.7 with an average playing experience of 12 years participated in the study. There was a 100% occurrence of at least one injury with an average rate of 5.98 injuries per person. The authors observed that the most commonly injured anatomical region is the lower extremity; ankles were recorded as the most commonly injured part. Other commonly injured areas included the shoulders and lower back. Furthermore, the most common injury type is tendinitis, sprains, and strains. The recorded injuries were mostly associated with overuse injuries, and the findings were similar to those of most other studies on tennis injuries. A larger sample size may provide more conclusive findings on tennis injuries, particularly in different levels of competition, such as recreational or professional athletes.

  10. Towards Generic Models of Player Experience

    DEFF Research Database (Denmark)

    Shaker, Noor; Shaker, Mohammad; Abou-Zleikha, Mohamed

    2015-01-01

    -dependent and their applicability is usually limited to the system and the data used for model construction. Establishing models of user experience that are highly scalable while maintaing the performance constitutes an important research direction. In this paper, we propose generic models of user experience in the computer games...... further examine whether generic features of player be- haviour can be defined and used to boost the modelling per- formance. The accuracies obtained in both experiments in- dicate a promise for the proposed approach and suggest that game-independent player experience models can be built.......Context personalisation is a flourishing area of research with many applications. Context personalisation systems usually employ a user model to predict the appeal of the context to a particular user given a history of interactions. Most of the models used are context...

  11. Macro-players in stock markets

    CERN Document Server

    Röhner, B M

    2005-01-01

    It is usually assumed that stock prices reflect a balance between large numbers of small individual sellers and buyers. However, over the past fifty years mutual funds and other institutional shareholders have assumed an ever increasing part of stock transactions: their assets, as a percentage of GDP, have been multiplied by more than one hundred. The paper presents evidence which shows that reactions to major shocks are often dominated by a small number of institutional players. Most often the market gets a wrong perception and inadequate understanding of such events because the relevant information (e.g. the fact that one mutual fund has sold several million shares) only becomes available weeks or months after the event, through reports to the Securities and Exchange Commission (SEC). Our observations suggest that there is a radical difference between small ($ 5% $) price changes which, on the contrary, may be caused by massive sales (or purchases) by a few players. This suggests that the mechanisms which a...

  12. Evolutionary game theory: molecules as players.

    Science.gov (United States)

    Bohl, Katrin; Hummert, Sabine; Werner, Sarah; Basanta, David; Deutsch, Andreas; Schuster, Stefan; Theissen, Günter; Schroeter, Anja

    2014-12-01

    In this and an accompanying paper we review the use of game theoretical concepts in cell biology and molecular biology. This review focuses on the subcellular level by considering viruses, genes, and molecules as players. We discuss in which way catalytic RNA can be treated by game theory. Moreover, genes can compete for success in replication and can have different strategies in interactions with other genetic elements. Also transposable elements, or "jumping genes", can act as players because they usually bear different traits or strategies. Viruses compete in the case of co-infecting a host cell. Proteins interact in a game theoretical sense when forming heterodimers. Finally, we describe how the Shapley value can be applied to enzymes in metabolic pathways. We show that game theory can be successfully applied to describe and analyse scenarios at the molecular level resulting in counterintuitive conclusions.

  13. Left ventricular biomechanics in professional football players.

    Science.gov (United States)

    von Lueder, T G; Hodt, A; Gjerdalen, G F; Steine, K

    2017-04-04

    Chronic exercise induces adaptive changes of left ventricular (LV) ejection and filling capacities which may be detected by novel speckle-tracking echocardiography (STE) and tissue Doppler imaging (TDI)-based techniques. A total of 103 consecutive male elite Norwegian soccer players and 46 age-matched healthy controls underwent echocardiography at rest. STE was used to assess LV torsional mechanics and LV systolic longitudinal strain (LS). Diastolic function was evaluated by trans-mitral blood flow, mitral annular velocities by TDI, and LV inflow propagation velocity by color M-mode. Despite similar global LS, players displayed lower basal wall and higher apical wall LS values vs controls, resulting in an incremental base-to-apex gradient of LS. Color M-mode and TDI-derived data were similar in both groups. Peak systolic twist rate (TWR) was significantly lower in players (86.4±2.8 vs controls 101.9±5.2 deg/s, Pplayers (-124.5±4.2 vs -106.9±6.7 deg/s) and peaked earlier during the cardiac cycle (112.7±0.8 vs 117.4±2.4% of systole duration, both Pplayers. Augmented diastolic wall strain (DWS), a novel measure of LV compliance in players, was associated with improved myocardial mechanical efficiency. The described myocardial biomechanics may underlie augmented exertional cardiac function in athletes and may have a potential role to characterize athlete's heart by itself or to distinguish it from hypertensive or hypertrophic cardiomyopathy. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. The El Dorado of Handball? Foreign Female Players Stay, while Domestic Players Return from Abroad.

    Science.gov (United States)

    Bon, Marta; Topič, Mojca Doupona; Šibila, Marko

    2016-04-01

    The main purpose of this research was to study the characteristics of migration in European women's handball based on the Slovenian example and to find the differences between the foreigners coming to Slovenia and the Slovenians transferring to foreign clubs. The research was based on 16 open face-to-face semi-structured interviews (8 Slovenians (age 29.5 ± 6.2 years) and 8 foreigners (age 35.5 ± 8.7 years)). We found out that the most powerful factor in foreigners was the financial one, while within Slovenian players it was their personal desire for progression within their sport, the club's reputation and poor conditions in their previous club. The results confirm that when making a decision on transfer, all players had the support of family and friends, while the clubs of foreign players were not as supportive. Most interviewees considered their careers successful and did not regret going abroad. The research indicates that the largest differences discovered between Slovenians and foreigners were that foreign female players chose to stay in the new country (Slovenia), while domestic players returned home after few years playing abroad. In conclusion, the results show that in top-level handball there are important differences between migration models which are based on nationality and also that the migration models change throughout time, which is largely connected with the socioeconomic events in the country of origin or transfer.

  15. Tibia and fibula fractures in soccer players.

    Science.gov (United States)

    Boden, B P; Lohnes, J H; Nunley, J A; Garrett, W E

    1999-01-01

    We performed a retrospective review of 31 athletes who sustained a fracture of the lower leg from a direct blow while playing soccer. Fifteen fractures involved both the tibia and fibula 11 only the tibia, and 5 only the fibula. Information was collected using a standardized questionnaire. The mean follow-up from the time of injury was 30 months. Injuries typically occurred in young, competitive athletes during game situations. The mechanisms were broadly classified into several categories: contact during a slide tackle (13, 42%), a collision with the goalkeeper (8, 26%), two opposing players colliding while swinging for a loose ball (7, 23%), or a player being kicked by a standing opponent (3, 10%). The majority of fractures (26, 90%) occurred while the athletes were wearing shin guards. The point of impact was with the shin guard prior to the fracture in 16 cases (62%). Return to competitive soccer averaged 40 weeks for combined tibia and fibula fractures, 35 weeks for isolated tibia fractures, and 18 weeks for isolated fibula fractures. Injuries were associated with a high incidence of major complications (12 out of 31, 39%), especially in concurrent tibia and fibula fractures (8 out of 15, 50%). These findings suggest that lower leg fractures in soccer players are serious injuries, often necessitating a prolonged recovery time. In addition, this study questions the ability of shin guards to protect against fractures.

  16. EVALUATING AUSTRALIAN FOOTBALL LEAGUE PLAYER CONTRIBUTIONS USING INTERACTIVE NETWORK SIMULATION

    Directory of Open Access Journals (Sweden)

    Jonathan Sargent

    2013-03-01

    Full Text Available This paper focuses on the contribution of Australian Football League (AFL players to their team's on-field network by simulating player interactions within a chosen team list and estimating the net effect on final score margin. A Visual Basic computer program was written, firstly, to isolate the effective interactions between players from a particular team in all 2011 season matches and, secondly, to generate a symmetric interaction matrix for each match. Negative binomial distributions were fitted to each player pairing in the Geelong Football Club for the 2011 season, enabling an interactive match simulation model given the 22 chosen players. Dynamic player ratings were calculated from the simulated network using eigenvector centrality, a method that recognises and rewards interactions with more prominent players in the team network. The centrality ratings were recorded after every network simulation and then applied in final score margin predictions so that each player's match contribution-and, hence, an optimal team-could be estimated. The paper ultimately demonstrates that the presence of highly rated players, such as Geelong's Jimmy Bartel, provides the most utility within a simulated team network. It is anticipated that these findings will facilitate optimal AFL team selection and player substitutions, which are key areas of interest to coaches. Network simulations are also attractive for use within betting markets, specifically to provide information on the likelihood of a chosen AFL team list "covering the line".

  17. Sympathetic enhancement in futsal players but not in football players after repeated sprint ability test.

    Science.gov (United States)

    Chen, Yung-Sheng; Liao, Chih-Jung; Lu, Wan-An; Kuo, Cheng-Deng

    2015-01-01

    Heart rate variability (HRV) can disclose the specific adaptation of sympathovagal modulation to exercise. This study investigated the change in HRV measures after anaerobic and aerobic intermittent exercises in university football and futsal players. 36 male university students with physically active lifestyle (n=14), football (n=12), and futsal (n=10) participated in this study. The participants completed the repeated sprint ability (RSA) test and Yo-Yo (YY) intermittent recovery test level 1 in randomised order. ECG signals of the participants were recorded in supine position 15 min before and 30 min after exercises. Before exercise, and 5 and 30 min after exercise, the blood pressures were also taken. In the RSA protocol, the percentage changes in normalised high-frequency power (nHFP) were significantly decreased, while the percentage changes in the very low/high frequency power ratio (VLHR) and low/high frequency power ratio (LHR) were significantly increased in futsal players after exercise, as compared with the controls. No significant changes in all HRV indices were found in the YY protocol, except the respiratory frequency. After exercise, the percent decrease in vagal modulation in futsal players was significantly reduced, while the percentage increase in sympathetic modulation in futsal players was significantly enhanced in the RSA test, but not in the YY test, as compared with the control group. The increase in sympathetic activity and the decrease in vagal activity in the futsal players were greater than the corresponding increase and decrease in the football players in the RSA test.

  18. Vascular Health in American Football Players: Cardiovascular Risk Increased in Division III Players

    Directory of Open Access Journals (Sweden)

    Deborah L. Feairheller

    2016-01-01

    Full Text Available Studies report that football players have high blood pressure (BP and increased cardiovascular risk. There are over 70,000 NCAA football players and 450 Division III schools sponsor football programs, yet limited research exists on vascular health of athletes. This study aimed to compare vascular and cardiovascular health measures between football players and nonathlete controls. Twenty-three athletes and 19 nonathletes participated. Vascular health measures included flow-mediated dilation (FMD and carotid artery intima-media thickness (IMT. Cardiovascular measures included clinic and 24 hr BP levels, body composition, VO2 max, and fasting glucose/cholesterol levels. Compared to controls, football players had a worse vascular and cardiovascular profile. Football players had thicker carotid artery IMT (0.49 ± 0.06 mm versus 0.46 ± 0.07 mm and larger brachial artery diameter during FMD (4.3±0.5 mm versus 3.7±0.6 mm, but no difference in percent FMD. Systolic BP was significantly higher in football players at all measurements: resting (128.2±6.4 mmHg versus 122.4±6.8 mmHg, submaximal exercise (150.4±18.8 mmHg versus 137.3±9.5 mmHg, maximal exercise (211.3±25.9 mmHg versus 191.4±19.2 mmHg, and 24-hour BP (124.9±6.3 mmHg versus 109.8±3.7 mmHg. Football players also had higher fasting glucose (91.6±6.5 mg/dL versus 86.6±5.8 mg/dL, lower HDL (36.5±11.2 mg/dL versus 47.1±14.8 mg/dL, and higher body fat percentage (29.2±7.9% versus 23.2±7.0%. Division III collegiate football players remain an understudied population and may be at increased cardiovascular risk.

  19. Vascular Health in American Football Players: Cardiovascular Risk Increased in Division III Players

    Science.gov (United States)

    Feairheller, Deborah L.; Aichele, Kristin R.; Oakman, Joyann E.; Neal, Michael P.; Cromwell, Christina M.; Lenzo, Jessica M.; Perez, Avery N.; Bye, Naomi L.; Santaniello, Erica L.; Hill, Jessica A.; Evans, Rachel C.; Thiele, Karla A.; Chavis, Lauren N.; Getty, Allyson K.; Wisdo, Tia R.; McClelland, JoAnna M.; Sturgeon, Kathleen; Chlad, Pam

    2016-01-01

    Studies report that football players have high blood pressure (BP) and increased cardiovascular risk. There are over 70,000 NCAA football players and 450 Division III schools sponsor football programs, yet limited research exists on vascular health of athletes. This study aimed to compare vascular and cardiovascular health measures between football players and nonathlete controls. Twenty-three athletes and 19 nonathletes participated. Vascular health measures included flow-mediated dilation (FMD) and carotid artery intima-media thickness (IMT). Cardiovascular measures included clinic and 24 hr BP levels, body composition, VO2 max, and fasting glucose/cholesterol levels. Compared to controls, football players had a worse vascular and cardiovascular profile. Football players had thicker carotid artery IMT (0.49 ± 0.06 mm versus 0.46 ± 0.07 mm) and larger brachial artery diameter during FMD (4.3 ± 0.5 mm versus 3.7 ± 0.6 mm), but no difference in percent FMD. Systolic BP was significantly higher in football players at all measurements: resting (128.2 ± 6.4 mmHg versus 122.4 ± 6.8 mmHg), submaximal exercise (150.4 ± 18.8 mmHg versus 137.3 ± 9.5 mmHg), maximal exercise (211.3 ± 25.9 mmHg versus 191.4 ± 19.2 mmHg), and 24-hour BP (124.9 ± 6.3 mmHg versus 109.8 ± 3.7 mmHg). Football players also had higher fasting glucose (91.6 ± 6.5 mg/dL versus 86.6 ± 5.8 mg/dL), lower HDL (36.5 ± 11.2 mg/dL versus 47.1 ± 14.8 mg/dL), and higher body fat percentage (29.2 ± 7.9% versus 23.2 ± 7.0%). Division III collegiate football players remain an understudied population and may be at increased cardiovascular risk. PMID:26904291

  20. Energy Balance during Taekwondo Practice in Elite Male Taekwondo Players.

    Science.gov (United States)

    Cho, Kang Ok; Garber, Carol Ewing; Lee, Sukho; Kim, Yeon Soo

    2013-03-01

    The goal of this study was to evaluate energy expenditure and dietary intake of nutrients during Taekwondo practice in elite Korean male Taekwondo players. Elite Korean male high school (high school player: HP; n = 59) and college players (college player: CP; n = 58) wore an accelerometer to measure energy expenditure and recorded their daily dietary intake for nutritional analysis over the course of five days. Nutritional adequacy ratios for total energy (0.82), vitamin C (0.97), calcium (0.78), and folate (0.75) were below recommended levels for all players. When comparing daily nutrient intake and energy expenditure between HP and CP, the HP group had significantly higher total calorie intake (402.7 kcal, p Taekwondo practice, the total energy expenditure (151.2 kcal, p = 0.001), total activity counts (130,674 counts, p = 0.038) and energy expenditure during Taekwondo practice (257.7 kcal, p Taekwondo players.

  1. Heart rate and activity profile for young female soccer players

    OpenAIRE

    2008-01-01

    The physical and physiological demands of high-level male soccer have been studied extensively, while few studies have investigated the demands placed on females during match-play, however, there is no information available about the heart rate and activity profile of young female soccer players during match play. Therefore, the aim of this study was to examine cardiovascular (heart-rates HR) and physical demands of young female soccer players during a match. Players were observed during a fr...

  2. Temperamental Predictive Factors for Success in Korean Professional Baseball Players

    OpenAIRE

    Kang, Kyoung Doo; Han, Doug Hyun; Hannon, James C.; Hall, Morgan S.; Choi, Jae Won

    2015-01-01

    Objective In this five-year cohort study, we hypothesize that factors of temperament and character in professional baseball players predict the speed of obtaining success and the quality of success as well as anxiety control. Methods Participants included 120 male rookie players from the Korea Baseball Organization (KBO) and 107 male non-players with no history of playing baseball. The personality/characters and state/trait anxieties of participants were assessed with the Temperament and Char...

  3. Nutritional Habits & Knowledge in the Division I Collegiate Football Player

    OpenAIRE

    Hale, Mallory

    2013-01-01

    Objectives: Athlete’s nutritional habits and knowledge can directly affect their performance. The purpose of this study is to investigate the nutritional habits and knowledge of the Division I collegiate football player. Methods: The participants of this study are male Division I college football players at Utah State University. The athletes included 45 players ranging from 18-26 and include freshman through seniors. Results: Over eighty six percent of the athletes were unaware that a ...

  4. Towards Player Adaptivity in a Serious Game for Conflict Resolution

    DEFF Research Database (Denmark)

    Grappiolo, C.; Cheong, Yun-Gyung; Togelius, J.

    2011-01-01

    to resolve this type of conflict, the underlying system generates level content automatically which adapts to player experience and behaviour. Preliminary results demonstrate the efficiency of the procedural content generation mechanism in guiding the training of players towards targeted learning objectives.......We present a technology demonstrator for an adaptive serious game for teaching conflict resolution and discuss the research questions associated with the project. The prototype is a single-player 3D mini-game which simulates a resource management conflict scenario. In order to teach the player how...

  5. Arthroscopic Shoulder Surgery in Female Professional Tennis Players

    Science.gov (United States)

    Young, Simon W.; Safran, Marc R.; Dakic, Jodie; Nguyen, Michael L.; Stroia, Kathleen

    2013-01-01

    Objectives: Recent publications have highlighted the relatively poor outcome of other overhead athletes, particularly baseball players, with regard to return to sports at the same or higher level after shoulder surgery. However, true assessment of their ability when returning to sport is not as clear. Further, ability to return to other overhead sports has not been reported. Our objective was to assess outcome and time to return to previous level of function following shoulder surgery in professional tennis players. Methods: The records of all female tennis players on the Women’s Tennis Association (WTA) professional circuit between January 2008 and June 2010 were reviewed to identify players who underwent shoulder surgery on their dominant (serving) shoulder. Details of the surgery including date, procedures performed, and complications were recorded. The primary outcomes were ability and time to return to professional play, and if they were able to return to their previous level of function, as determined by singles ranking. Pre and post-operative singles rankings were used to determine rate and completeness of return to preoperative function. Their highest ranking pre-injury, post operatively, and the time to return to pre-injury ranking were evaluated. Results: During the study period eight professional women tennis players from the WTA underwent shoulder surgery on their dominant arm. All surgery was performed arthroscopically, 7 out of 8 players had more than one procedure performed during the surgery. In total, 3 players underwent debridement of a partial rotator cuff tear and 2 players underwent repair of a complete supraspinatus tear. Three players had an anterior labral repair or reconstruction for anterior instability, and one player underwent repair of a SLAP lesion. Two players underwent neurolysis of a suprascapular nerve, and three players in total underwent a subacromial decompression. All players (100%) returned to professional play. The mean

  6. A Multi-agent player for Settlers of Catan

    OpenAIRE

    2008-01-01

    There are many games that have been a challenge to Research in Artificial Intelligence. One such game is Settlers of Catan (SoC). The purpose of this thesis is to develop a Multi-agent player for SoC. Although it is difficult to focus on all the dimensions of the game during implementation, therefore a good enough solution is proposed. An emphasis is placed on building a good trader for the player. Once a working solution had been built, the player was tested against other players which inclu...

  7. Understanding the Mismatch Between Coaches' and Players' Perceptions of Exertion.

    Science.gov (United States)

    Brink, Michel S; Kersten, Anna W; Frencken, Wouter G P

    2017-04-01

    A mismatch between the training exertion intended by a coach and the exertion perceived by players is well established in sports. However, it is unknown whether coaches can accurately observe exertion of individual players during training. Furthermore, the discrepancy in coaches' and players' perceptions has not been explained. To determine the relation between intended and observed training exertion by the coach and perceived training exertion by the players and establish whether on-field training characteristics, intermittent endurance capacity, and maturity status explain the mismatch. During 2 mesocycles of 4 wk (in November and March), rating of intended exertion (RIE), rating of observed exertion (ROE), and rating of perceived exertion (RPE) were monitored in 31 elite young soccer players. External and internal training loads were objectively quantified with accelerometers (PlayerLoad) and heart-rate monitors (TRIMPmod). Results of an interval shuttle-run test (ISRT) and age at peak height velocity (APHV) were determined for all players. RIE, ROE, and RPE were monitored in 977 training sessions. The correlations between RIE and RPE (r = .58; P players will do and what they actually did on the field. When doing this, they consider the intermittent endurance capacity of individual players.

  8. Executive functions predict the success of top-soccer players.

    Science.gov (United States)

    Vestberg, Torbjörn; Gustafson, Roland; Maurex, Liselotte; Ingvar, Martin; Petrovic, Predrag

    2012-01-01

    While the importance of physical abilities and motor coordination is non-contested in sport, more focus has recently been turned toward cognitive processes important for different sports. However, this line of studies has often investigated sport-specific cognitive traits, while few studies have focused on general cognitive traits. We explored if measures of general executive functions can predict the success of a soccer player. The present study used standardized neuropsychological assessment tools assessing players' general executive functions including on-line multi-processing such as creativity, response inhibition, and cognitive flexibility. In a first cross-sectional part of the study we compared the results between High Division players (HD), Lower Division players (LD) and a standardized norm group. The result shows that both HD and LD players had significantly better measures of executive functions in comparison to the norm group for both men and women. Moreover, the HD players outperformed the LD players in these tests. In the second prospective part of the study, a partial correlation test showed a significant correlation between the result from the executive test and the numbers of goals and assists the players had scored two seasons later. The results from this study strongly suggest that results in cognitive function tests predict the success of ball sport players.

  9. Executive functions predict the success of top-soccer players.

    Directory of Open Access Journals (Sweden)

    Torbjörn Vestberg

    Full Text Available While the importance of physical abilities and motor coordination is non-contested in sport, more focus has recently been turned toward cognitive processes important for different sports. However, this line of studies has often investigated sport-specific cognitive traits, while few studies have focused on general cognitive traits. We explored if measures of general executive functions can predict the success of a soccer player. The present study used standardized neuropsychological assessment tools assessing players' general executive functions including on-line multi-processing such as creativity, response inhibition, and cognitive flexibility. In a first cross-sectional part of the study we compared the results between High Division players (HD, Lower Division players (LD and a standardized norm group. The result shows that both HD and LD players had significantly better measures of executive functions in comparison to the norm group for both men and women. Moreover, the HD players outperformed the LD players in these tests. In the second prospective part of the study, a partial correlation test showed a significant correlation between the result from the executive test and the numbers of goals and assists the players had scored two seasons later. The results from this study strongly suggest that results in cognitive function tests predict the success of ball sport players.

  10. Player Collaboration in the Explorative Sound Environment ToneInk

    DEFF Research Database (Denmark)

    Hansen, Anne-Marie S.; Andersen, Hans Jørgen; Raudaskoski, Pirkko Liisa

    2016-01-01

    In the present paper, ToneInk, a prototype of a music based play scenario that investigates player collaboration, is introduced. ToneInk is an explorative sound environment that differs from the majority of music based games in that players can collaborate and be creative in the way they express...... mutual awareness, and in general were more passive when they needed to monitor a screen interface that supported the sound environment. Player collaboration was strongest when players negotiated rhythm, while the negotiation of melody was temporally offset and consisted of long individual explorations....

  11. Membongkar Veto Player dalam Politik Kepartaian Indonesia Menuju Pemilu 2014

    Directory of Open Access Journals (Sweden)

    Arya Budi

    2014-05-01

    Full Text Available The article explains about how party elites, then identified as veto players, in Indonesia’s 2014 election organize themselve into party organization. The authority institutionalization of the veto player creates a decisional and positional quadrant of each party in terms of party politics of 2014 election. The findings of veto player pattern in such a party politics confirm forms of a centripetal force of politics in party organization. Finally, veto player behavior causes a spectrum of political cybernetics among political parties based on its turbulence, cohesiveness, and switching elites.

  12. Concussion knowledge in high school football players.

    Science.gov (United States)

    Cournoyer, Janie; Tripp, Brady L

    2014-01-01

    Participating in sports while experiencing symptoms of a concussion can be dangerous. An athlete's lack of knowledge may be one factor influencing his or her decision to report symptoms. In an effort to enhance concussion education among high school athletes, legislation in Florida has attempted to address the issue through parental consent forms. To survey high school varsity football players to determine their level of knowledge about concussions after the initiation of new concussion-education legislation. Cross-sectional study. Descriptive survey administered in person during a team meeting. A total of 334 varsity football players from 11 high schools in Florida. Participants completed a survey and identified the symptoms and consequences of a concussion among distractors. They also indicated whether they had received education about concussions from a parent, formal education, neither, or both. The most correctly identified symptoms were headache (97%), dizziness (93%), and confusion (90%), and the most correctly identified consequence was persistent headache (93%). Participants reported receiving education from their parents (54%) or from a formal source (60%). Twenty-five percent reported never receiving any education regarding concussions. No correlations were found between the method of education and the knowledge of symptoms or consequences of concussion. The high school football players we surveyed did not have appropriate knowledge of the symptoms and consequences of concussions. Nausea or vomiting, neck pain, grogginess, difficulty concentrating, and personality or behavioral changes were often missed by participants, and only a small proportion correctly identified brain hemorrhage, coma, and death as possible consequences of inappropriate care after a concussion. Even with parents or guardians signing a consent form indicating they discussed concussion awareness with their child, 46% of athletes suggested they had not.

  13. A new game plan for C players.

    Science.gov (United States)

    Axelrod, Beth; Handfield-Jones, Helen; Michaels, Ed

    2002-01-01

    It's a big driver of business success, but one that executives are loath to talk about: upgrading the talent pool by weeding out "C" players from management. These aren't the incompetent or unethical managers whom organizations dismiss without a backward glance; C performers deliver results that are acceptable--barely--but they fail to innovate or to inspire the people they lead. The authors of The War for Talent have studied what it takes to upgrade an organization's talent pool. In this article, they explore the hidden costs of tolerating under-performance and acknowledge the reasons why executives may shy away from dealing decisively with C players. They recommend that organizations take an "iron hand in a velvet glove" approach to managing subpar performers. That is, companies should establish rigorous, disciplined processes for assessing and dealing with low-performing managers but still treat them with respect. The authors outline three ironhanded steps. First, executives must identify C players by evaluating their talents and distributing employee performances along an assessment curve. Second, executives must agree on explicit action plans that articulate the improvements or changes that C performers must achieve within six to 12 months. And third, executives should hold managers accountable for carrying out the action plans. Without such discipline, procrastination, rationalization, and inaction will prevail. The authors also emphasize the need for the "velvet glove." Executives must ensure that low performers are treated with dignity, so they should offer candid feedback, instructive coaching, and generous severance packages and outplacement support. The authors' approach isn't about being tough on people; it's about being relentlessly focused on performance.

  14. Comparison of Shoulder Strength in Routinely Trained Badminton Players and Non-Badminton Players

    Directory of Open Access Journals (Sweden)

    Wong Zhen Feng

    2017-06-01

    Full Text Available Background: Shoulder pain is a common reason for patients to seek medical help in any healthcare center. Shoulder pain is influenced by a few factors such as gender, posture during daily activities, aging and psychological factors. Based on the study of Epidemiology of Injuries and Prevention Strategies in Competitive Swimmers, shoulder pain due to shoulder injuries can be reduced by strengthening the shoulder muscle. Badminton has become one of the most popular sports in Asia, especially in Indonesia. This study was conducted to determine if badmintonis able to strengthen the shoulder muscle group. Methods: A cross-sectional analytic experimental study was conducted on September 2015 at Lodaya Badminton Training Center and Bale Padjadjaran of Universitas Padjadjaran. Subjects were 30 healthy male routinely trained badminton players and 30 non-badminton players who voluntarily follow the rstudy procedures. Strength measurement procedures were provided to the subjects after getting informed consent.  Data analysis was performed using T-test. Results: The shoulder strength  in routinely trained badminton players was significantly different from  non-badminton players (P<0.05. Conclusions: Shoulder strength can be improved through routine training of badminton to reduce risk of shoulder injury.   DOI: 10.15850/amj.v4n2.1083

  15. Probabilistic one-player Ramsey games via deterministic two-player games

    CERN Document Server

    Belfrage, Michael; Spöhel, Reto

    2009-01-01

    Consider the following probabilistic one-player game: The board is a graph with $n$ vertices, which initially contains no edges. In each step, a new edge is drawn uniformly at random from all non-edges and is presented to the player, henceforth called Painter. Painter must assign one of $r$ available colors to each edge immediately, where $r \\geq 2$ is a fixed integer. The game is over as soon as a monochromatic copy of some fixed graph $F$ has been created, and Painter's goal is to 'survive' for as many steps as possible before this happens. We present a new technique for deriving upper bounds on the threshold of this game, i.e., on the typical number of steps Painter will survive with an optimal strategy. More specifically, we consider a deterministic two-player variant of the game where the edges are not chosen randomly, but by a second player Builder. However, Builder has to adhere to the restriction that, for some real number $d$, the ratio of edges to vertices in all subgraphs of the evolving board neve...

  16. DIFFERENCES IN FUNCTIONAL AND MOTOR ABILITIES OFYOUNG FOOTBALL PLAYERS, BASKETBALL AND VOLLEYBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Franja Fratrić

    2009-11-01

    Full Text Available The main goal of this research is to determine whether and what differences exist between the three groups of subjects (high-quality football, volleyball and basketball cadets and youth age, in the motoric and functional abilities, as well as to identify dif- ferences between subgroups within each sport. The sample consists of 61 volleyball, 31 basketball player and football player 31 (total n = 123 male, cadet and youth age are members of local clubs. Subjects were born between 01.01.1991 and 12.12.1994. The sample of variables are the values of 17 tests for the evaluation of functional and mobile status. The Motor-functional status on the basis of the results of secondary value of foot- ball, basketball and volleyball make a clear conclusion that the football players showed the best results in almost all the tests and that they had the smallest disbalance in the power of certain groups of muscles.The football players hve the highest homogeneity.

  17. Meniscal ossicle in a professional soccer player.

    Science.gov (United States)

    Ogassawara, R; Zayni, R; Orhant, E; Noel, E; Fournier, Y; Hager, J-P; Chambat, P; Sonnery-Cottet, B

    2011-06-01

    Meniscal ossicles are an unusual finding and a rare cause for knee pain. They are often initially diagnosed as a loose body, chondrocalcinosis or meniscal calcification within the knee joint. Few cases have been reported in the literature. We present a case of a meniscal ossicle with an associated femoral cartilage lesion in a healthy 26-year-old male professional soccer player who presented with swelling and pain. The purpose of this article is to discuss the origins, radiological features, clinical symptoms and prognosis of meniscal ossicles.

  18. Payoff Shares in Two-Player Contests

    Directory of Open Access Journals (Sweden)

    Samuel Häfner

    2016-09-01

    Full Text Available In imperfectly discriminating contests with symmetric valuations, equilibrium payoffs are positive shares of the value of the prize. In contrast to a bargaining situation, players’ shares sum to less than one because a residual share of the value is lost due to rent dissipation. In this paper, we consider contests with two players and investigate the relationship between these equilibrium shares and the parameters of a class of asymmetric Tullock contest success functions. Our main finding is that any players’ shares that sum up to less than one can arise as the unique outcome of a pure-strategy Nash equilibrium for appropriate parameters.

  19. Acing common skin problems in tennis players.

    Science.gov (United States)

    Basler, R S; Garcia, M A

    1998-12-01

    The following measures can help prevent skin disorders in tennis players: wearing properly fitted shoes to avoid tennis toe, talon noir, and calluses; applying lubricants to protect against blisters and chafing; washing skin thoroughly to reduce the risk of acne mechanica; and wearing a hat and sunscreen to guard against photoinjury. 'Stringer's fingers' can be prevented by breaking the habit of adjusting the racket strings after each point. Should these disorders become troublesome, conservative treatments are usually effective. For example, calluses may be carefully pared, and pain from a subungual hemorrhage can be relieved by piercing the toenail with a hot paper clip.

  20. Predicting Player Churn In the Wild

    DEFF Research Database (Denmark)

    Hadiji, Fabian; Sifa, Rafet; Drachen, Anders;

    2014-01-01

    a crucial value, allowing developers to obtain data-driven insights to inform design, development and marketing strategies. One of the key challenges is modeling and predicting player churn. This paper presents the first cross-game study of churn prediction in Free-to-Play games. Churn in games is discussed...... with the individual retention model for each game in the dataset used, we develop a broadly applicable churn prediction model, which does not rely on gamedesign specific features. The presented classifiers are applied on a dataset covering five free-to-play games resulting in high accuracy churn prediction....

  1. Match analysis and player characteristics in rugby sevens.

    Science.gov (United States)

    Ross, Alex; Gill, Nicholas; Cronin, John

    2014-03-01

    Rugby sevens is a contact sport contested by two teams of seven players who compete over two 7-min halves, most frequently played in a tournament style. The IRB Sevens World Series is thought of as the preeminent rugby sevens competition in the world and has grown in competitiveness from its inception in 2000. The decision to include rugby sevens in the 2016 Olympics is likely to increase the global profile and participation in the game. Many rugby sevens players concurrently compete in 15-a-side rugby union as backs and loose forwards; however, a continued increase in the popularity of rugby sevens will likely see the emergence of the specialist rugby sevens player. Often thought of as the abbreviated version of rugby union, rugby sevens is played under nearly identical laws and on the same field dimensions as the 15-man code. However, research has shown the movement demands of rugby sevens and rugby union are dissimilar, with rugby sevens players spending a larger proportion of the game running at high intensity (≥ 5 m s(-1)). Given the dissimilarity in match demands in conjunction with differences in the competition structure between the codes, it appears the considerable depth of literature specific to performance in rugby union may be of little value for the preparation of rugby sevens players. Investigations of the physical characteristics of rugby sevens players show backs are lighter and shorter than forwards, while players across all positions possess a lean body composition. International rugby sevens players have similar speed characteristics to rugby union backs across distances of 10-30 m; however, rugby sevens players appear to have superior intermittent aerobic endurance. Despite being of likely importance, little is known of the strength and power characteristics of rugby sevens players. Research into the speed and aerobic endurance characteristics of rugby sevens players has not distinguished between backs and forwards and, as such, it is unclear

  2. Sex-specific differences in injury types among basketball players

    Directory of Open Access Journals (Sweden)

    Ito E

    2014-12-01

    Full Text Available Eri Ito, Jun Iwamoto, Koichiro Azuma, Hideo MatsumotoInstitute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, JapanAbstract: The purpose of the present study was to investigate sex-specific differences in injury types among basketball players. According to our database, during the 20-year period between October 1991 and June 2011, 1,219 basketball players (640 males and 579 females consulted our sports medicine clinic; in total, 1,414 injuries in basketball players (729 injuries in males and 685 injuries in females were recorded. The mean age of patients was 19.6 years. The most common injury site was the knee, followed by the foot and ankle, lower back, and upper extremities. There was a higher proportion of female players presenting with a knee injury, compared with male players (50.4% vs 41.7%, and a lower proportion of female players presenting with an upper extremity injury (5.1% vs 9.7%. The proportion of anterior cruciate ligament injury in the 10–19-year-old age group was higher among female players than among male players (45.9% vs 22.1%, while the proportions of Osgood–Schlatter disease in the 10–19-year-old age group and jumper's knee (patellar and femoral tendinopathy in the 20–29-year-old age group were higher among male players than among female players (12.5% vs 1.8% and 14.6% vs 3.7%, respectively. However, the proportions of other injuries did not differ significantly between male and female players. The present observational study, which was performed using a retrospective case-series design, showed the existence of sex-specific differences in knee injuries sustained while participating in basketball.Keywords: sports injury, sex, anterior cruciate ligament injury, Osgood–Schlatter disease, basketball

  3. Strength asymmetry of the shoulders in elite volleyball players.

    Science.gov (United States)

    Hadzic, Vedran; Sattler, Tine; Veselko, Matjaž; Markovic, Goran; Dervisevic, Edvin

    2014-01-01

    Volleyball players are reported to have shoulder strength imbalances. Previous authors have primarily investigated small samples of male players at a single skill level, without considering playing position, and with inconsistent findings. To evaluate shoulder strength asymmetry and a history of shoulder injury in a large sample of professional volleyball players of both sexes across different playing positions and skill levels. Descriptive laboratory study. A sample of 183 volleyball players (99 men, 84 women). We assessed shoulder internal-rotator and external-rotator concentric strength at 60°/s using an isokinetic dynamometer and dominant-nondominant differences in shoulder strength and strength ratios using repeated-measures analyses of variance. Peak torque was normalized for body mass and external-rotation/internal-rotation concentric strength. Internal-rotation strength was asymmetric in favor of the dominant side in both sexes, regardless of previous shoulder injury status. Male volleyball players had a lower shoulder strength ratio on the dominant side, regardless of previous shoulder injury status. However, this finding was valid only when hand dominance was taken into account. Female volleyball players playing at a higher level (ie, first versus second division) were 3.43 times more likely to have an abnormal strength ratio. Playing position was not associated with an abnormal shoulder strength ratio or strength asymmetry. In male volleyball players, the external-rotation/internal-rotation strength ratio of the dominant shoulder was lower, regardless of playing position, skill level, or a previous shoulder injury. In female players, the ratio was less only in those at a higher skill level. Although speculative, these findings generally suggest that female volleyball players could have a lower risk of developing shoulder-related problems than male volleyball players. Isokinetic shoulder testing may reveal important information about the possible risk

  4. Scapula Kinematics of Youth Baseball Players

    Directory of Open Access Journals (Sweden)

    Oliver Gretchen

    2015-12-01

    Full Text Available Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg, with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER and maximum humeral internal rotation (MIR during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly.

  5. Scapula Kinematics of Youth Baseball Players.

    Science.gov (United States)

    Oliver, Gretchen; Weimar, Wendi

    2015-12-22

    Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg), with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER) and maximum humeral internal rotation (MIR) during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly.

  6. Sport commitment in adolescent soccer players

    Directory of Open Access Journals (Sweden)

    Noelia Belando Pedreño

    2016-03-01

    Full Text Available The aim of this study was to contribute to the postulates of the self-determination theory, the hierarchical model of intrinsic and extrinsic motivation by Vallerand, and social goals. A structural regression model was estimated to analyze the relations between social goals (responsibility and relationships, praise for autonomous behavior, satisfaction of the basic psychological needs and intrinsic motivation in commitment to sport. A sample of 264 young Spanish soccer players aged between 14 and 16 (M =14.74, SD =.77 participated in the study. Structural Equation Modeling results showed that the social responsibility goal, the social relationship goal and praise for autonomous behavior predicted perceived competence. Furthermore, the relationship goal also predicted the need for relatedness. Satisfaction of the basic psychological needs for competence and relatedness predicted intrinsic motivation. Intrinsic motivation positively predicted future commitment to sport. These results highlighted the importance of social goals, praise for autonomous behavior and psychological mediators in encouraging greater commitment in young soccer players. Future research should focus on the coach’s role in generating greater commitment to sport through the development of intervention methodologies based on social goals.

  7. Protective Equipment and Player Characteristics Associated With the Incidence of Sport-Related Concussion in High School Football Players

    Science.gov (United States)

    McGuine, Timothy A.; Hetzel, Scott; McCrea, Michael; Brooks, M. Alison

    2015-01-01

    Background The incidence of sport-related concussion (SRC) in high school football is well documented. However, limited prospective data are available regarding how player characteristics and protective equipment affect the incidence of SRC. Purpose To determine whether the type of protective equipment (helmet and mouth guard) and player characteristics affect the incidence of SRC in high school football players. Design Cohort study; Level of evidence, 2. Methods Certified athletic trainers (ATs) at each high school recorded the type of helmet worn (brand, model, purchase year, and recondition status) by each player as well as information regarding players’ demographics, type of mouth guard used, and history of SRC. The ATs also recorded the incidence and days lost from participation for each SRC. Incidence of SRC was compared for various helmets, type of mouth guard, history of SRC, and player demographics. Results A total of 2081 players (grades 9–12) enrolled during the 2012 and/or 2013 football seasons (2287 player-seasons) and participated in 134,437 football (practice or competition) exposures. Of these players, 206 (9%) sustained a total of 211 SRCs (1.56/1000 exposures). There was no difference in the incidence of SRC (number of helmets, % SRC [95% CI]) for players wearing Riddell (1171, 9.1% [7.6%–11.0%]), Schutt (680, 8.7% [6.7%–11.1%]), or Xenith (436, 9.2% [6.7%–12.4%]) helmets. Helmet age and recondition status did not affect the incidence of SRC. The rate of SRC (hazard ratio [HR]) was higher in players who wore a custom mouth guard (HR = 1.69 [95% CI, 1.20–2.37], P football players. Players who had sustained an SRC within the previous 12 months were more likely to sustain an SRC than were players without a history of SRC. Sports medicine providers who work with high school football players need to realize that factors other than the type of protective equipment worn affect the risk of SRC in high school players. PMID:25060072

  8. Gender Differences in Coping among Elite Table Tennis Players

    Science.gov (United States)

    Kirimoglu, Huseyin

    2011-01-01

    The current study aims to investigate the explanatory power of social support and coping in relation to a competitive sport event between male and female table tennis players. 246 university students table tennis players (120 men and 126 women) from different region and part of Turkey were invited to participate in a survey study included the…

  9. Development of repeated sprint ability in talented youth basketball players.

    NARCIS (Netherlands)

    Wierike, S.C. te; Jong, M.C. de; Tromp, E.J.; Vuijk, P.J.; Lemmink, K.A.; Malina, R.M.; Elferink-Gemser, M.T.; Visscher, C.

    2013-01-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14 to 19 years of age (16.1±1.7 years). Players were observed on six occasions during the 2008-2009 and 2009-2010 seasons. Three basketball-specific field tests were administe

  10. Relative risk for concussions in young female soccer players.

    Science.gov (United States)

    Strand, Sarah; Lechuga, David; Zachariah, Thomas; Beaulieu, Kathryn

    2015-01-01

    The objective of this study was to determine the relative risk and reported symptoms of concussions in 11- to 13-year-old, female soccer players. For this, a survey to compare the reported incidence of concussion in age-matched female soccer players to nonsoccer players was performed. The survey included 342 girls between the ages of 11 and 13: 195 were involved in an organized soccer team and 147 were not involved in organized soccer but were allowed to participate in any other sport or activity. A total of 94 of the 195 soccer players, or 48%, reported at least one symptom consistent with a concussion. The most prevalent symptom for these girls was headache (84%). A total of 34 of the 147 nonsoccer players, or 23%, reported at least one symptom consistent with a concussion in the previous six months. These results determined that the relative risk of probable concussions among 11- to 13-year-old, female soccer players is 2.09 (p concussions in young female soccer players is significantly higher than in a control group of nonsoccer players of the same sex and age.

  11. Development of repeated sprint ability in talented youth basketball players.

    NARCIS (Netherlands)

    Koen A.P.M. Lemmink; S.C. te Wierike; E.J. Tromp; M.T. Elferink-Gemser; M.C. de Jong; R.M. Malina; P.J. Vuijk; C. Visscher

    2013-01-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14 to 19 years of age (16.1±1.7 years). Players were observed on six occasions during the 2008-2009 and 2009-2010 seasons. Three basketball-specific field tests were

  12. [Muscular trunk stability in professional and amateur volleyball players].

    Science.gov (United States)

    Miltner, O; Siebert, C; Tschaepe, R; Maus, U; Kieffer, O

    2010-03-01

    The aim of this study was to analyse the efficiency of muscular activity in the trunk stabilisation of professional volleyball players compared to a group of amateur hobby players. The results were compared amongst the groups as well as with a reference group consisting of asymptomatic individuals. The question to be answered was whether or not professional volleyball players possess a characteristic strength profile in their trunk musculature and if differences exist with regard to the individuals' competitive playing level. In this comparative study 12 professional volleyball players (German Bundesliga) and 18 non-professional volleyball players were analysed with regard to their isometric strength profile in all three planes. The reference group was provided by the Proxomed company, which had previously analysed healthy untrained individuals (n = 1045) of various age groups. A sports-specific profile for the musculature of volleyball players revealed a significant reduction in the flexion and rotation strength as well as a well-developed lateral flexion strength (highly significant when compared to the reference group). With reference to the level played, better strength values in flexion and lateral flexion were found among the professional athletes. Professional volleyball players present with a characteristic trunk musculature strength profile. A detailed analysis of the muscle strength of the spine as part of a sports medicine work-up could prove helpful in preventing injuries and overuse problems in professional and hobby volleyball players.

  13. Player Collaboration in the Explorative Sound Environment ToneInk

    DEFF Research Database (Denmark)

    Hansen, Anne-Marie; Andersen, Hans Jørgen; Raudaskoski, Pirkko Liisa

    2016-01-01

    mutual awareness, and in general were more passive when they needed to monitor a screen interface that supported the sound environment. Player collaboration was strongest when players negotiated rhythm, while the negotiation of melody was temporally offset and consisted of long individual explorations....

  14. Differences in energy capacities between tennis players and runners.

    Science.gov (United States)

    Novak, Dario; Vucetić, Vlatko; Zugaj, Sanja

    2013-05-01

    The primary purpose of this study was to determine differences between elite athletes and tennis players in order to provide a clearer picture regarding the energy demands in modern tennis. Forty-eight (48) athletes and 24 tennis players from Croatian national leagues were compared in morphological and physiological parameters of an all-out incremental treadmill test with gas exchange measurements. Tennis players' HRmax (192.96+/-7.75 bpm) shows values that are most different to 400-meters sprinters (200.13+/-6.95 bpm). Maximum running speed of tennis players on the treadmill (vmax) is no different with the speed achieved by sprinters, while there are significant differences among other athletes. Values in running speed at anaerobic threshold (vAnT) show no statistically significant difference with the values for athlete sprinters and 400-m sprinters. Values of RvO2max for tennis players indicate significant similarities with athlete sprinters and 400-m sprinters while the values of RvO2AnT are nearly identical with the values for sprinters and show no statistically significant differences (ptennis players approximate most different those of the middle and long distance runners. This singles out the possible importance of the anaerobic capacity and the high level of sprint endurance in tennis players. Knowing these characteristics is the basis for planning and implementing training systems that will enable the increase and optimal usage of energy capacities of tennis players in possibly improving sports results.

  15. Translucent Players: Explaining Cooperative Behavior in Social Dilemmas

    Directory of Open Access Journals (Sweden)

    Valerio Capraro

    2016-06-01

    Full Text Available In the last few decades, numerous experiments have shown that humans do not always behave so as to maximize their material payoff. Cooperative behavior when non-cooperation is a dominant strategy (with respect to the material payoffs is particularly puzzling. Here we propose a novel approach to explain cooperation, assuming what Halpern and Pass call translucent players. Typically, players are assumed to be opaque, in the sense that a deviation by one player in a normal-form game does not affect the strategies used by other players. But a player may believe that if he switches from one strategy to another, the fact that he chooses to switch may be visible to the other players. For example, if he chooses to defect in Prisoner's Dilemma, the other player may sense his guilt. We show that by assuming translucent players, we can recover many of the regularities observed in human behavior in well-studied games such as Prisoner's Dilemma, Traveler's Dilemma, Bertrand Competition, and the Public Goods game.

  16. Labor Market Structure and Salary Determination among Professional Basketball Players.

    Science.gov (United States)

    Wallace, Michael

    1988-01-01

    The author investigates the labor market structure and determinants of salaries for professional basketball players. An expanded version of the resource perspective is used. A three-tiered model of labor market segmentation is revealed for professional basketball players, but other variables also are important in salary determination. (Author/CH)

  17. The Mental Skills Training of University Soccer Players

    Science.gov (United States)

    Sadeghi, Hassan; Omar-Fauzee, Mohd-Sofian; Jamalis, Marjohan; Ab-Latif, Rozita; Cheric, Majid Chahrdah

    2010-01-01

    The purpose of this study is to identify the kind of mental skills training needed most by the university soccer players. Eight male university football players (aged 25 to 36) from one large university in Kuala Lumpur agreed to participate in this study. On average, they have 10 years of playing experience. All of them have signed the informed…

  18. Differences in Soccer Kick Kinematics between Blind Players and Controls

    Science.gov (United States)

    Giagazoglou, Paraskevi; Katis, Athanasios; Kellis, Eleftherios; Natsikas, Christos

    2011-01-01

    The purpose of the current study was to examine the kinematic differences during instep soccer kicks between players who were blind and sighted controls. Eleven male soccer players who were blind and nine male sighted performed instep kicks under static and dynamic conditions. The results indicated significantly higher (p less than 0.05) ball…

  19. Playing time between senior rugby players of different ethnic groups ...

    African Journals Online (AJOL)

    Discovery High Performance Centre, Sports Science Institute of South Africa, and MRC/UCT Research Unit for Exercise ... nutritional advice, life skills and technical rugby coaching. The ... Players were given feedback on their performance in each of the 3 ..... the skill acquisition that is required by a high-level adult player.

  20. Development of repeated sprint ability in talented youth basketball players.

    NARCIS (Netherlands)

    Koen A.P.M. Lemmink; S.C. te Wierike; E.J. Tromp; M.T. Elferink-Gemser; M.C. de Jong; R.M. Malina; P.J. Vuijk; C. Visscher

    2013-01-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14 to 19 years of age (16.1±1.7 years). Players were observed on six occasions during the 2008-2009 and 2009-2010 seasons. Three basketball-specific field tests were administe

  1. Analysis of motor activities of professional soccer players.

    Science.gov (United States)

    Andrzejewski, Marcin; Chmura, Jan; Pluta, Beata; Kasprzak, Andrzej

    2012-06-01

    The objective of this study was to determine the distance covered by professional soccer players during matches with the use of the computerized match analysis system Amisco Pro® (version 1.0.2, Nice, France). Kinematic examination included the specification of the distance covered by 31 players participating in 4 matches in the Union of European Football Association Cup competitions during the 2008-2009 season. Data were analyzed based on players' positions on the pitch, changes in the players' motor activity intensity level, and match period (first or second half). The results of statistical analysis revealed that the average total distance covered by all players (n = 31) was 11,288 ± 734 m. With respect to the player's position on the pitch, the midfielders traveled the longest average distance (11,770 ± 554 m) during the game. This was 3% longer than the distance achieved by the attackers at 11,377 ± 584 m, and 7% longer than that achieved by the defenders 10,932 ± 728 m. The analysis of physical loads on soccer players during a match is highly useful for training individualization. It provides a tool for effective planning and for recording the loads on players, which is an indispensable element of modern coaching.

  2. Neuropsychological consequence of soccer play in adolescent U.K. School team soccer players.

    Science.gov (United States)

    Stephens, Richard; Rutherford, Andrew; Potter, Douglas; Fernie, Gordon

    2010-01-01

    To assess mild head injury effects in adolescent soccer players, neuropsychological performance across school team soccer players, rugby players and noncontact sport players was assessed in a quasi-experimental cross-sectional design. One hundred eighty-five males were tested (ages 13-16; response rate 55%) and 86 contributed data to the analyses after exclusion for recent concussion and overlapping sports participation. Soccer players showed lower premorbid intellectual functioning, but neither soccer players nor rugby players showed neuropsychological decrement compared with noncontact sport players. Cumulative heading did not predict neuropsychological performance. While no specific attribute of soccer was linked with neuropsychological impairment, head injury predicted reduced attention for all participants.

  3. Evaluating the heading in professional soccer players by playing positions.

    Science.gov (United States)

    Erkmen, Nurtekin

    2009-09-01

    The aim of this study is to evaluate the accuracy and coordination of heading in professional soccer players of different positions. A total of 243 professional soccer players were examined for the study. The Federation Internationale de Football Association Medical Assessment and Research Center (F-MARC) test battery was used to evaluate heading in soccer players. In the heading of the ball thrown from middle of the goal, forwards were better than goalkeepers (p heading of the ball thrown from the right side of the goalpost, defenders were better than goalkeepers (p heading of goalkeepers being worse than the others; goalkeepers use their hands in both training and matches, whereas for forwards and defensive players being better than goalkeepers depends mainly on their positions in soccer. Trainers and coaches should give place specific training programs to improve heading ability in the training schedule of soccer players at a professional level.

  4. Shoulder injuries in rugby players: mechanisms, examination, and rehabilitation.

    Science.gov (United States)

    Helgeson, Kevin; Stoneman, Paul

    2014-11-01

    The sport of rugby is growing in popularity for players at the high school and collegiate levels. This article will provided the sports therapist with an introduction to the management of shoulder injuries in rugby players. Rugby matches results in frequent impacts and leveraging forces to the shoulder region during the tackling, scrums, rucks and maul components of the game. Rugby players frequently sustain contusion and impact injuries to the shoulder region, including injuries to the sternoclavicular, acromioclavicular (AC), and glenohumeral (GH) joints. Players assessed during practices and matches should be screened for signs of fracture, cervical spine and brachial plexus injuries. A three phase program will be proposed to rehabilitate players with shoulder instabilities using rugby specific stabilization, proprioception, and strengthening exercises. A plan for return to play will be addressed including position-specific activities. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. A Method for Using Player Tracking Data in Basketball to Learn Player Skills and Predict Team Performance.

    Directory of Open Access Journals (Sweden)

    Brian Skinner

    Full Text Available Player tracking data represents a revolutionary new data source for basketball analysis, in which essentially every aspect of a player's performance is tracked and can be analyzed numerically. We suggest a way by which this data set, when coupled with a network-style model of the offense that relates players' skills to the team's success at running different plays, can be used to automatically learn players' skills and predict the performance of untested 5-man lineups in a way that accounts for the interaction between players' respective skill sets. After developing a general analysis procedure, we present as an example a specific implementation of our method using a simplified network model. While player tracking data is not yet available in the public domain, we evaluate our model using simulated data and show that player skills can be accurately inferred by a simple statistical inference scheme. Finally, we use the model to analyze games from the 2011 playoff series between the Memphis Grizzlies and the Oklahoma City Thunder and we show that, even with a very limited data set, the model can consistently describe a player's interactions with a given lineup based only on his performance with a different lineup.

  6. Bone Mineral Density of Adolescent Female Tennis Players and Nontennis Players

    Directory of Open Access Journals (Sweden)

    Kevser Ermin

    2012-01-01

    Full Text Available The purpose of this study was to determine differences in bone mineral density (BMD among adolescent female tennis players (TPs and nontennis players (NTPs and to assess body composition as a predictor variable of BMD. Nineteen female TPs and 19 female NTPs, ages 14 to 18 years, participated in this study. Lumbar spine, total hip, femoral neck, forearms BMD, and body composition were assessed using dual-energy X-ray absorptiometry (DXA. Lumbar spine and total hip BMD measurements for TP were greater than NTP. However, these differences were not statistically significant (=0.37 and 0.12, resp.. TP had significantly greater femoral neck BMD than NTPs (=0.02. This difference might play an important role in preventing osteoporosis and decreasing the risk of fractures at the hip later in life.

  7. Sympathetic enhancement in futsal players but not in football players after repeated sprint ability test

    OpenAIRE

    Chen, Yung-Sheng; Liao, Chih-Jung; Lu, Wan-An; Kuo, Cheng-Deng

    2015-01-01

    Background Heart rate variability (HRV) can disclose the specific adaptation of sympathovagal modulation to exercise. This study investigated the change in HRV measures after anaerobic and aerobic intermittent exercises in university football and futsal players. Method 36 male university students with physically active lifestyle (n=14), football (n=12), and futsal (n=10) participated in this study. The participants completed the repeated sprint ability (RSA) test and Yo-Yo (YY) intermittent r...

  8. Coach/player relationships in tennis.

    Science.gov (United States)

    Prapavessis, H; Gordon, S

    1991-09-01

    The present study examined the variables that predict coach/athlete compatibility. Compatibility among a sample of 52 elite tennis coach/player dyads was assessed using a sport adapted version of Schutz's (1966) Fundamental Interpersonal Relations Orientation-Behaviour (FIRO-B), a sport adapted version of Fiedler's (1967) Least Preferred Co-worker scale (LPC), and Chelladurai and Saleh's (1980) Leadership Scale for Sport (LSS). Self-ratings of the quality of the interaction were obtained from both coach and athlete. Multiple-regression analyses using self-rating scores as the dependent measure were carried out to determine which variables best predicted the degree of compatibility. The sole inventory that significantly predicted compatibility was the LSS. More specifically, the discrepancy between the athlete's preferences and perceptions on the autocratic dimension was the best predictor. Implications for tennis coaches and recommendations for future research in this area are discussed.

  9. Gamification in Fostering Creativity: Player Type Approach

    Directory of Open Access Journals (Sweden)

    Marius Kalinauskas

    2015-02-01

    Full Text Available Purpose – to analyze gamification, as the method for promoting creativity in individual and collective levels with the respect to player types.Design/methodology/approach – This research serves as a general review/viewpoint which seeks to examine collective creativity as a phenomenon and gamification as the tool for promoting individual and collective creativity. The paper is based on the comparative analysis of scientific literature and related sources from game design, psychology, business and entertainment.Findings – Although the gamification is gaining more public attention, there is a lack of studies which would reveal its relations in fostering individual and collective creativity. One of the main goals of any gamified content is to raise the engagement into activities in non-game contexts. The objective of creative work is to come up with some ideas, methods or tools which would be significantly new and innovative in the case of a certain issue. The theory of “flow” is used widely in explaining the working principles of gamification. In this state, the information absorption rates are increased and the group or individual is immersed into performed activities. This may lead to prolonged periods while accumulating knowledge, and thus, improving creative capabilities in the specific domain. However, creative performance in different fields has various approaches. It is also related to personal characteristics. The success of gamification is also dependent on the types of “players” which participate in the activity. Having the common picture of personality type in creative performance and in game based tasks may allow creating gamification strategy for optimal engagement into creative work according to the features of a person.Research limitations/implications – There are very few empirical studies which would support correlation between experiencing the “flow” state and a raise of creativity. The idea of unified

  10. Cellular Players in Skeletal Muscle Regeneration

    Directory of Open Access Journals (Sweden)

    Laura Cristina Ceafalan

    2014-01-01

    Full Text Available Skeletal muscle, a tissue endowed with remarkable endogenous regeneration potential, is still under focused experimental investigation mainly due to treatment potential for muscle trauma and muscular dystrophies. Resident satellite cells with stem cell features were enthusiastically described quite a long time ago, but activation of these cells is not yet controlled by any medical interventions. However, after thorough reports of their existence, survival, activation, and differentiation there are still many questions to be answered regarding the intimate mechanism of tissue regeneration. This review delivers an up-to-date inventory of the main known key players in skeletal muscle repair, revealed by various models of tissue injuries in mechanical trauma, toxic lesions, and muscular dystrophy. A better understanding of the spatial and temporal relationships between various cell populations, with different physical or paracrine interactions and phenotype changes induced by local or systemic signalling, might lead to a more efficient approach for future therapies.

  11. Morphological classification of novice female volleyball players

    Directory of Open Access Journals (Sweden)

    José António Ribeiro Maia

    2003-12-01

    Full Text Available The characteristics of physique have been the subject of several studies in sport sciences because high-level competitive sports place maximum demands on the physical constitution of players. Furthermore, the specifi c function performed by a player in a game may be related to a particular modality. The goals of this study were: (1 to describe and to compare, from a somatic point of view, the physiques of 71 female volleyball players at beginner levels A and B (aged 12-14 years; and (2 to identify the components of somatic structure that best differentiate the athletics by level of experience. In order to evaluate the players’ somatic structure,we performed 21 measurements including: weight and height, diameters, circumferences, upper and lower limb measurements and skinfolds thicknesses. Discriminant function analysis (DFA was used to identify the power of variables classifi cation. No difference was found in physique between level A and level B players. They were classifi ed by somatotype as mesomorphic endomorphs (A = 4.76 - 3.78 - 1.85; and B = 4.37 - 4.02 - 1.88. RESUMO As características morfológicas têm sido objeto de vários estudos em Ciências Desporto, pelo fato de o fenômeno do desporto de alta competição exigir o máximo da estrutura física dos atletas e pela expectativa da função que o atleta desempenha em jogo. O presente estudo teve como objetivo: (1 descrever e comparar, do ponto de vista somático, a estrutura morfológica de 71 atletas de voleibol do sexo feminino dos escalões de formação A e B (entre os 12 e 14 anos de idade; (2 identifi car os componentes da estrutura somática que melhor diferenciam as atletas de níveis distintos. Para a avaliação da estrutura somática das atletas foram efetuadas 21 avaliações, incluindo além do peso e altura, comprimento dos membros, perímetros, diâmetros e pregas de adiposidade subcutâneas. Com o intuito de verifi car o poder discriminatório das variáveis na

  12. Stem Cells and Neuroprotection: Understanding the Players

    Directory of Open Access Journals (Sweden)

    Virginia Pearce

    2010-09-01

    Full Text Available The use of neuroprotective therapies begs the question of how such therapies could affect preexisting stem cell populations within the host, as well as those introduced through cell-replacement therapy. Multiple mechanisms may mediate stem cell responses to neuroprotectants such as host/donor age and gender, cellular lineage/differentiation status, and mitochondrial dynamics. Current therapeutic sources for stem cells are embryonic, somatic, or induced pluripotent, with very little known about the effects of gender, age, cell type, and mitochondrial dynamics. With the advent of therapies to stimulate and recruit endogenous stem cells or transplant donor cells into damage areas in the hopes of recuperative regeneration of lost neurons, it is important to discuss mechanisms that dictate the winning players in the neuroprotection game. This review will focus on our current understanding of the characteristics of renewing stem cells that may affect neuroprotection.

  13. University Football Players, Postural Stability, and Concussions.

    Science.gov (United States)

    Graves, Barbara Sue

    2016-02-01

    Concussion in football athletes is certainly more prevalent and has potentially serious outcomes. With current concerns and increasing return-to-play issues, additional assessment focus is needed. Division 1 college football athletes, from 18 to 20.9 years (n = 177; age, 19.7 ± 1.2 years; height, 182.3 ± 4.5 cm; weight, 97.3 ± 10.6 kg), before fall practice, over a period of 3 years, underwent baseline postural stability testing (sensory organization test [SOT], NeuroCom). Individuals, who were diagnosed with a concussion (headache, dizziness, fatigue, confusion, or loss of consciousness) during practice or actual competition (n = 15; age, 18.9 ± 0.9 years; height, 181.8 ± 2.5 cm; weight, 86.6 ± 3.6 kg), underwent serial evaluation after injury and 24 hours after concussion. As soon as the player was considered asymptomatic, the test was completed on the first and 14th day. A control group of noninjured male athletes (n = 15; age, 19.1 ± 0.4 years; height, 178.2 ± 3.2 cm; weight, 78.6 ± 2.1 kg) were tested for the same time frame. This particular study was only one part of the total evaluation conducted for the concussed athlete's return to play. Results indicated that the concussion group had a statistically significant (p = 0.037) change from their baseline SOT score and the control group (p = 0.025). This change remained significant until day 14 of posttesting. These data indicate that the SOT, when available, may be a positive additional assessment of concussed college-aged football players. Professionals, when dealing with concussion in competitive sports, do need to continue to work together, but awareness of SOT assessments may also contribute to the return-to-play decisions.

  14. SPORTS SHOES PURCHASE INTENTION AMONG MALAYSIAN VOLLEYBALL PLAYERS VS. NON-VOLLEYBALL PLAYERS: A CONCEPTUAL PAPER

    Directory of Open Access Journals (Sweden)

    GOH PIN SIANG

    2013-12-01

    Full Text Available The purpose of this study is to advance the understanding of volleyball players’ purchase intention toward sport shoes by investigating the relationship between the independent variables (endorsement, advertising, pricing and electronic word-of-mouth and purchase intention. Descriptive research and causal research will be used as the research design, thus questionnaire and experimentation will be used to obtain data. Primary data in this study is attained by distributing the questionnaire to the Malaysian volleyball players throughout several volleyball tournament venues in Malaysia. The experiment will be conducted by comparing two groups of respondents, including volleyball players and non-volleyball players. This study is limited to several independent variables such as endorsement, advertising, pricing and electronic word-of-mouth. This study is significant for marketers for solving the challenges faced in the sport industry. It also helps to identify consumers’ purchase preferences for sport shoes. The marketer would understand more about their targeted customers’ intentions to purchase, thus the sport industry related with sport marketing in Malaysia might gain more profit.

  15. Cervical range of motion and proprioception in rugby players versus non-rugby players.

    Science.gov (United States)

    Lark, Sally D; McCarthy, Peter W

    2007-06-01

    In this study, we examined the effects of number of years of playing rugby on neck function. Active cervical spine range of motion and proprioception were assessed in 14 non-rugby-playing but trained sportsmen (mean age 28 years, s = 7) and 46 rugby players (26 rugby forwards: mean age 26 years, s = 5; mean years played 14 years; 20 backs: mean age 24 years, s = 5; mean years played 14 years). Active cervical range of motion in flexion, extension, left and right lateral flexion, plus left and right rotation were measured using a cervical range of motion device. The ability to reposition the head in a central position with eyes closed was taken as a measure of proprioception. Results show that rugby forwards generally had the least active cervical range of motion, particularly neck extension (forwards, 43 degrees ; backs, 55 degrees ; controls, 58 degrees ), with the decrement correlating with the number of years played. In addition, repositioning was significantly worse in rugby players after neck extension than non-rugby players (6 degrees vs. 3 degrees ). The active cervical range of motion of rugby forwards is similar to that of whiplash patients, suggesting that participation in rugby can have an effect on neck range of motion that is equivalent to chronic disability. Reduced active cervical range of motion could also increase the likelihood of injury and exacerbate age-related neck problems.

  16. Soccer and Relative Age Effect: A Walk among Elite Players and Young Players

    Directory of Open Access Journals (Sweden)

    Manuel Jacob Sierra-Díaz

    2017-01-01

    Full Text Available Grouping people according to chronological age is popular in fields such as education and sport. Athletes who are born in the first months of the year usually have cognitive and physical development differences in contrast to those born in the last months of the same year. That is why competitive teams tend to select older players more often than youngsters. Age differences between athletes born in the same year as well as an over-representation of older players are known as the Relative Age Effect. This effect is extensively described in young and elite team sports such as basketball, volleyball or, ice-hockey, as well as in soccer. The purpose of this study is to examine the state-of-the-art of the Relative Age Effect in youth and elite soccer players. This review summarizes recent research articles on the Relative Age Effect related to competitive soccer from 2010 to 2016. The systematic literature search was conducted in four databases: SPORTDiscus, Medline, EBSCO host and Google Scholar. Although causes and final solutions have not been clearly achieved yet, it is necessary to continue investigating this phenomenon in order to provide a starting point for future research.

  17. Sport-specific factors predicting player retention in junior cricket.

    Science.gov (United States)

    Talpey, Scott; Croucher, Tom; Bani Mustafa, Ahmed; Finch, Caroline F

    2017-04-01

    Understanding factors that motivate young athletes to continue participation in sport can help key stakeholders cultivate an environment that fosters long-term participation. This investigation sought to determine the performance and participation factors that influenced continued participation in junior cricket. Administration-level data were collected each annual season across a seven-year period by a community-level junior cricket association in Australia and analysed to identify the performance and participation-based predictors of player retention. All players were males aged <16 years. Players were categorised according to whether they remained in (or departed from) the association at the end of each playing season. A multivariate logistic regression model with a stepwise variable selection was employed to identify significant independent predictors of player retention. The number of innings batted and overs bowled were significant participation-related contributors to junior cricket player retention. Performance factors such as the number of wickets taken and the number of runs scored also significantly influenced player retention. Finally, team age group, the number of previous seasons played and age were also significant factors in player retention. This demonstrates that sufficient opportunity for children to participate in the game and expression of skills competence are key factors for retention in cricket.

  18. Active tuning of stroke-induced vibrations by tennis players.

    Science.gov (United States)

    Chadefaux, Delphine; Rao, Guillaume; Androuet, Philippe; Berton, Eric; Vigouroux, Laurent

    2017-08-01

    This paper investigates how tennis players control stroke-induced vibration. Its aim is to characterise how a tennis player deals with entering vibration waves or how he/she has the ability to finely adjust them. A specific experimental procedure was designed, based on simultaneously collecting sets of kinematic, vibration and electromyographic data during forehand strokes using various commercial rackets and stroke intensities. Using 14 expert players, a wide range of excitations at spectral and temporal levels were investigated. Energetic and spectral descriptors of stroke-induced vibration occurring at the racket handle and at the player's wrist and elbow were computed. Results indicated that vibrational characteristics are strongly governed by grip force and to a lower extent by the racket properties. Grip force management drives the amount of energy, as well as its distribution, into the forearm. Furthermore, hand-grip can be assimilated to an adaptive filter which can significantly modify the spectral parameters propagating into the player's upper limb. A significant outcome is that these spectral characteristics are as much dependent on the player as on the racket. This contribution opens up new perspectives in equipment manufacture by underlining the need to account for player/racket interaction in the design process.

  19. A Novel Music Player Controlling Design Based on Gesture Recognition

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2014-01-01

    Full Text Available This study has proposed a novel music player controlling method based on gesture recognition, which translating the gesture interacting signal into a controlling instruction for the music player. Firstly, utilizing the laptop’s webcam to capture the image information, and then employing the image processing method to tackle it. The skin color detection was used to obtain the information of gesture candidates, and a background subtraction was introduced to eliminate the distributing information. Moreover, in order to ensure the rapid and effective implementation of music player proposed here, the barycenter of a gesture was calculated as one Recognized Reference Information (RRI; a ratio between the gesture’s width and height was also selected as the other RRI; the comparison of these two RRI values was utilized to obtain a pattern signal of the gesture which was corresponding to the controlling instruction for the Music Player. Eventually, a Music Player was programmed and the pattern signal generated by gesture recognition was used to control the Music Player as willing to realize four basic functions: “play”, “pause”, “previous” and “next”. A series of tests using our gesture recognition based Music Player was conducted under the condition with different kinds of complex backgrounds, and the results showed the satisfactory performance of our interactive designing.

  20. Physical performance of elite and subelite Spanish female futsal players

    Science.gov (United States)

    Rubio-Arias, JA; Carrasco-Poyatos, M; Alcaraz, PE

    2016-01-01

    The aim of this study was to determine the parameters distinguishing top female futsal players from lower level players. Twenty-seven female futsal players participated in the study, composed of professional first division (elite; n = 15) players and semi-professional second division players (sub-elite; n = 14). Active and passive straight leg raise tests, isokinetic strength of the knee extensor and flexor muscles at 60° · s-1 angular velocity, squat and counter movement jumps, 30 m sprint, 30 m agility, repeated sprint ability test and maximum ball speed during shooting were measured. The elite players were more agile and kicked harder than sub-elite players in maximum ball speed during the shooting test (P ≤ 0.05). However, no significant differences between teams were observed in active and passive hamstring flexibility, jumping ability, repeated sprint ability test, 30 m sprint time, H/Q ratio and absolute and relative torque from 60° · s-1 angular velocity. Based on these findings we conclude that agility and maximum ball speed during shooting may be important determinant factors of Spanish female futsal actions and could distinguish ability at high-level games. PMID:27601786

  1. Physical performance of elite and subelite Spanish female futsal players

    Directory of Open Access Journals (Sweden)

    DJ Ramos-Campo

    2016-08-01

    Full Text Available The aim of this study was to determine the parameters distinguishing top female futsal players from lower level players. Twenty-seven female futsal players participated in the study, composed of professional first division (elite; n=15 players and semi-professional second division players (sub-elite; n=14. Active and passive straight leg raise tests, isokinetic strength of the knee extensor and flexor muscles at 60º • s-1 angular velocity, squat and counter movement jumps, 30 m sprint, 30 m agility, repeated sprint ability test and maximum ball speed during shooting were measured. The elite players were more agile and kicked harder than sub-elite players in maximum ball speed during the shooting test (P≤0.05. However, no significant differences between teams were observed in active and passive hamstring flexibility, jumping ability, repeated sprint ability test, 30 m sprint time, H/Q ratio and absolute and relative torque from 60° • s-1 angular velocity. Based on these findings we conclude that agility and maximum ball speed during shooting may be important determinant factors of Spanish female futsal actions and could distinguish ability at high-level games.

  2. Throwing speed and accuracy in baseball and cricket players.

    Science.gov (United States)

    Freeston, Jonathan; Rooney, Kieron

    2014-06-01

    Throwing speed and accuracy are both critical to sports performance but cannot be optimized simultaneously. This speed-accuracy trade-off (SATO) is evident across a number of throwing groups but remains poorly understood. The goal was to describe the SATO in baseball and cricket players and determine the speed that optimizes accuracy. 20 grade-level baseball and cricket players performed 10 throws at 80% and 100% of maximal throwing speed (MTS) toward a cricket stump. Baseball players then performed a further 10 throws at 70%, 80%, 90%, and 100% of MTS toward a circular target. Baseball players threw faster with greater accuracy than cricket players at both speeds. Both groups demonstrated a significant SATO as vertical error increased with increases in speed; the trade-off was worse for cricketers than baseball players. Accuracy was optimized at 70% of MTS for baseballers. Throwing athletes should decrease speed when accuracy is critical. Cricket players could adopt baseball-training practices to improve throwing performance.

  3. Tracking of Ball and Players in Beach Volleyball Videos

    Science.gov (United States)

    Gomez, Gabriel; Herrera López, Patricia; Link, Daniel; Eskofier, Bjoern

    2014-01-01

    This paper presents methods for the determination of players' positions and contact time points by tracking the players and the ball in beach volleyball videos. Two player tracking methods are compared, a classical particle filter and a rigid grid integral histogram tracker. Due to mutual occlusion of the players and the camera perspective, results are best for the front players, with 74,6% and 82,6% of correctly tracked frames for the particle method and the integral histogram method, respectively. Results suggest an improved robustness against player confusion between different particle sets when tracking with a rigid grid approach. Faster processing and less player confusions make this method superior to the classical particle filter. Two different ball tracking methods are used that detect ball candidates from movement difference images using a background subtraction algorithm. Ball trajectories are estimated and interpolated from parabolic flight equations. The tracking accuracy of the ball is 54,2% for the trajectory growth method and 42,1% for the Hough line detection method. Tracking results of over 90% from the literature could not be confirmed. Ball contact frames were estimated from parabolic trajectory intersection, resulting in 48,9% of correctly estimated ball contact points. PMID:25426936

  4. SUPERSTITIOUS BEHAVIOR AMONG JUDO, TAEKWONDO AND BOXING PLAYERS

    Directory of Open Access Journals (Sweden)

    Gaurav Dureja

    2016-04-01

    Full Text Available Purpose: The present study was designed to measure superstitious behavior among Judo, Taekwondo and Boxing players. Material: Thirty (N=30 male inter-college level players with the age group of 19-25 years were selected through purposive sampling technique to act as subjects from affiliated colleges of Panjab University, Chandigarh. They were further divided into three groups: Group-A [Judo (n=10], Group-B [Taekwondo (n=10] and Group-C [Boxing (n=10]. One Way Analysis of Variance (ANOVA was applied to find out the differences among judo, taekwondo and boxing players. Where ‘F’ values found significant, Least Significant Differences (LSD Post-hoc test was applied to find out the direction and degree of difference. Results: The level of significance was set at 0.05. The result revealed significant differences among judo, taekwondo and boxing players on the sub parameters: clothing and appearance, preparation, team ritual and coach. However, no significant differences have been observed on the sub-parameters fetish, game/competition, prayer and parameter superstitious (Total. Conclusions: The obtained results showed significant differences on the sub-parameter Coach among Judo, Taekwondo and Boxing players. While calculating the mean values of entire groups, it has been observed that Boxing players demonstrate significantly better on the sub-parameter Coach. Therefore, it can be ascertained that Boxing players are more confident that coach bring a lucky charm to our game.

  5. Somatotype, size and body composition of competitive female volleyball players.

    Science.gov (United States)

    Malousaris, Grigoris G; Bergeles, Nikolaos K; Barzouka, Karolina G; Bayios, Ioannis A; Nassis, George P; Koskolou, Maria D

    2008-06-01

    The aim of this study was to describe the morphological characteristics of competitive female volleyball players. For this purpose, body weight and height, breadths and girths as well as skinfold thickness at various body sites were assessed in 163 elite female volleyball players (age: 23.8+/-4.7 years, years of playing: 11.5+/-4.2, hours of training per week: 11.9+/-2.9, means+/-S.D.). Seventy-nine of these players were from the A1 division and the rest from the A2 division of the Greek National League. Two-way ANOVA was used to compare the differences in these characteristics between competition level and playing position. Body height ranged from 161cm to 194cm, and the mean value (177.1+/-6.5cm) was not inferior to that of international players of similar calibre. Adiposity of these players (sum of 5 skinfolds: 51.8+/-10.2mm, percent body fat: 23.4+/-2.8) was higher than that reported in other studies in which, however, different methodology was used. Volleyball athletes of this study were mainly balanced endomorphs (3.4-2.7-2.9). The A1 division players were taller and slightly leaner with greater fat-free mass than their A2 counterparts. Significant differences were found among athletes of different playing positions which are interpreted by their varying roles and physical demands during a volleyball game. The volleyball players who play as opposites were the only subgroup of players differing between divisions; the A2 opposites had more body fat than A1 opposites. These data could be added in the international literature related to the anthropometric characteristics of competitive female volleyball players.

  6. Performance Outcomes After Metacarpal Fractures in National Basketball Association Players.

    Science.gov (United States)

    Guss, Michael S; Begly, John P; Ramme, Austin J; Hinds, Richard M; Karia, Raj J; Capo, John T

    2016-12-01

    Background: The aim was to determine whether players in the National Basketball Association (NBA) who sustain metacarpal fractures demonstrate decreased performance upon return to competition when compared with their performance before injury and that of their control-matched peers. Methods: Data for 32 NBA players with metacarpal fractures incurred over 11 seasons (2002-2003 to 2012-2013) were obtained from injury reports, press releases, and player profiles (www.nba.com and www.basketballreference.com). Player age, body mass index (BMI), position, shooting hand, number of years in the league, and treatment (surgical vs nonsurgical) were recorded. Individual season statistics for the 2 seasons immediately prior to injury and the 2 seasons after injury, including player efficiency rating (PER), were obtained. Thirty-two controls matched by player position, age, and performance statistics were identified. A performance comparison of the cohorts was performed. Results: Mean age at the time of injury was 27 years with an average player BMI of 24. Players had a mean 5.6 seasons of NBA experience prior to injury. There was no significant change in PER when preinjury and postinjury performances were compared. Neither injury to their shooting hand nor operative management of the fracture led to a decrease in performance during the 2 seasons after injury. When compared with matched controls, no significant decline in performance in PER the first season and second season after injury was found. Conclusion: NBA players sustaining metacarpal fractures can reasonably expect to return to their preinjury performance levels following appropriate treatment.

  7. A Profile of Fitness Parameters and Performance of Volleyball Players

    Directory of Open Access Journals (Sweden)

    Govind B. Taware

    2013-07-01

    Full Text Available Background: Ball games require comprehen-sive ability including physical, technical, men-tal and tactical abilities. Among them, physicalabilities of players exert marked effects on theskill of the players themselves and the tacticsof the team. Therefore players must have thephysical abilities to meet the demand of thesport. Volleyball is one of the most popularlyplayed games in the world. Unfortunately, thelevel of performance of the Indian volleyballplayers lags far behind the international stan-dards. Aim of the Study: The present study wasaimed to assess flexibility, muscular endurance,power and cardio-respiratory endurance of vol-leyball players and to compare the results withage matched controls. Also, to compare thefindings of the volleyball players with that ofthe international norms from the available lit-erature and to make some suggestions for theimprovement in their performance level. Ma-terial and Methods: The study was carried outin 40 male volleyball players aged between 17to 26 years and 40 ages matched male controls.Physical fitness parameters namely flexibility,muscular endurance, power and cardio-respi-ratory endurance were measured, data was ana-lyzed using unpaired ‘t’-test. Results: It was ob-served that all physical fitness parameters weresignificantly more in players as compared totheir aged-matched controls but when values ofthe subjects were compared to internationalstandards; our subjects were behind the recom-mended norms for the elite volleyball players.Conclusion: The volleyball players have moreadvantage of flexibility muscular endurance,power and cardio-respiratory endurance.

  8. Management of female handball players' activity applying interactive technologies

    Directory of Open Access Journals (Sweden)

    Frolova L.S.

    2012-04-01

    Full Text Available The efficiency of developed methods for the control of female handball players' readiness to competitive activity was determined. The opportunities of team management regarding the specification of playing role, the formation of the starting line of players and the replacement according to game priorities in attack or defense were considered. The availability of the adequate zone of handball players' mobilizing readiness that allows to have a significant influence on individual effectiveness in the conditions of optimal management and to increase the quality of team game was determined.

  9. Design of a WAV audio player based on K20

    Directory of Open Access Journals (Sweden)

    Xu Yu

    2016-01-01

    Full Text Available The designed player uses the Freescale Company’s MK20DX128VLH7 as the core control ship, and its hardware platform is equipped with VS1003 audio decoder, OLED display interface, USB interface and SD card slot. The player uses the open source embedded real-time operating system μC/OS-II, Freescale USB Stack V4.1.1 and FATFS, and a graphical user interface is developed to improve the user experience based on CGUI. In general, the designed WAV audio player has a strong applicability and a good practical value.

  10. Vitamin D profile in National Football League players.

    Science.gov (United States)

    Maroon, Joseph C; Mathyssek, Christina M; Bost, Jeffrey W; Amos, Austin; Winkelman, Robert; Yates, Anthony P; Duca, Mark A; Norwig, John A

    2015-05-01

    By maintaining phosphate and calcium homeostasis, vitamin D is critical for bone health and possibly physical performance. Hence, vitamin D is important to athletes. Few studies have investigated vitamin D levels in relation to fractures and performance in athletes, and no published study has included a multiracial sample of professional American football players. To assess vitamin D levels, including the prevalence of vitamin D deficiency/insufficiency, in professional American football players and to evaluate the association of vitamin D levels with race, fracture history, and the ability to obtain a contract position, which may be a marker for athletic performance. Cohort study; Level of evidence, 3. Serum vitamin D levels of 80 professional football players from a single team in the National Football League were obtained during the 2011 off-season (mean age, 26.5±3.7 years; black, n=67 [84%]). These levels were used to compare injury reports from the 2011-2012 and 2012-2013 seasons. Statistical analyses were performed to test if vitamin D levels were related to race, fracture history, and the ability to obtain a contract position. Mean vitamin D level was 27.4±11.7 ng/mL, with significantly lower levels for black players (25.6±11.3 ng/mL) versus white players (37.4±8.6 ng/mL; F 1,78=13.00, P=.001). All athletes who were vitamin D deficient were black. When controlling for number of professional years played, vitamin D levels were significantly lower in players with at least 1 bone fracture when compared with no fractures. Players who were released during the preseason because of either injury or poor performance had significantly lower vitamin D levels than did players who played in the regular season. Black professional football players have a higher rate of vitamin D deficiency than do white players. Furthermore, professional football players with higher vitamin D levels were more likely to obtain a contract position in the National Football League

  11. Particle Swarm Optimization of Electricity Market Negotiating Players Portfolio

    DEFF Research Database (Denmark)

    Pinto, Tiago; Vale, Zita; Sousa, Tiago

    2014-01-01

    for market players. The ALBidS system allows MASCEM market negotiating players to take the best possible advantages from each market context. However, it is still necessary to adequately optimize the players’ portfolio investment. For this purpose, this paper proposes a market portfolio optimization method......, based on particle swarm optimization, which provides the best investment profile for a market player, considering different market opportunities (bilateral negotiation, market sessions, and operation in different markets) and the negotiation context such as the peak and off-peak periods of the day...

  12. Cryptographically Blinded Games: Leveraging Players' Limitations for Equilibria and Profit

    DEFF Research Database (Denmark)

    Hubacek, Pavel; Park, Sunoo

    2014-01-01

    In this work we apply methods from cryptography to enable mutually distrusting players to implement broad classes of mediated equilibria of strategic games without trusted mediation. Our implementation uses a pre-play 'cheap talk' phase, consisting of non- binding communication between players pr...... prior to play in the original game. In the cheap talk phase, the players run a secure multi-party computation protocol to sample from an equilibrium of a "cryptographically blinded" version of the game, in which actions are encrypted...

  13. Thermoregulation, Fluid Balance, and Sweat Losses in American Football Players.

    Science.gov (United States)

    Davis, Jon K; Baker, Lindsay B; Barnes, Kelly; Ungaro, Corey; Stofan, John

    2016-10-01

    Numerous studies have reported on the thermoregulation and hydration challenges athletes face in team and individual sports during exercise in the heat. Comparatively less research, however, has been conducted on the American Football player. Therefore, the purpose of this article is to review data collected in laboratory and field studies and discuss the thermoregulation, fluid balance, and sweat losses of American Football players. American Football presents a unique challenge to thermoregulation compared with other sports because of the encapsulating nature of the required protective equipment, large body size of players, and preseason practice occurring during the hottest time of year. Epidemiological studies report disproportionately higher rates of exertional heat illness and heat stroke in American Football compared with other sports. Specifically, larger players (e.g., linemen) are at increased risk for heat ailments compared with smaller players (e.g., backs) because of greater body mass index, increased body fat, lower surface area to body mass ratio, lower aerobic capacity, and the stationary nature of the position, which can reduce heat dissipation. A consistent finding across studies is that larger players exhibit higher sweating rates than smaller players. Mean sweating rates from 1.0 to 2.9 L/h have been reported for college and professional American Football players, with several studies reporting 3.0 L/h or more in some larger players. Sweat sodium concentration of American Football players does not seem to differ from that of athletes in other sports; however, given the high volume of sweat loss, the potential for sodium loss is higher in American Football than in other sports. Despite high sweating rates with American Football players, the observed disturbances in fluid balance have generally been mild (mean body mass loss ≤2 %). The majority of field-based studies have been conducted in the northeastern part of the United States, with limited

  14. Generative Agents for Player Decision Modeling in Games

    DEFF Research Database (Denmark)

    Holmgård, Christoffer; Liapis, Antonios; Togelius, Julian

    2014-01-01

    This paper presents a method for modeling player decision making through the use of agents as AI-driven personas. The paper argues that artificial agents, as generative player models, have properties that allow them to be used as psyhometrically valid, abstract simulations of a human player...... to or divergence from these. Essentially, at each step the action of the human is compared to what actions a number of reinforcement-learned agents would have taken in the same situation, where each agent is trained using a different reward scheme. Finally, extensions are outlined for adapting the agents...

  15. Sports players : the heroes of the mediated sacred sphere

    Directory of Open Access Journals (Sweden)

    María del Mar RUBIO-HERNÁNDEZ

    2011-01-01

    Full Text Available Broadcasted sport is one of the elements of the mediated culture which mobilizes extremely passionate masses. Thus, it can be considered as a mythical expression within current society, since contemporary era is witness to the revival of the sacred which manifests through rituals, myths and the divinization of certain products and celebrities. This article analyzes how media depictions exalt players as objects of worship and devotion. It will specifically focus on the most successful Spanish sportsmen such as the tennis player Rafael Nadal and the players of the national soccer team and how they are promoted as national heroes in advertising.

  16. CAREER TRANSITION FROM JUNIOR TO SENIOR IN BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Alberto Lorenzo

    2009-01-01

    Full Text Available The purpose of the study was to investigate what factors affect basketball players in the transition from junior and amateur to senior and professional sport respectively. The study was a qualitative research which uses a semi-structured interview to get the data. There were interviewed five Spanish basketball players who were starting playing in a team of Basketball Club Association (C.B.A.. The results showed that the participants face several changes both in the sport and in the life outside sport. At the same time, the results indicated the existence of several coping strategies that help the player in his career transition.

  17. Beneficial Long Communication in the Multi-Player Electronic Mail Game

    NARCIS (Netherlands)

    De Jaegher, K.J.M.

    2015-01-01

    In the two-player electronic mail game (EMG), as is well-known, the probability of collective action is lower the more confirmations and re-confirmations are made available to players. In the multi-player EMG, however, as we show players may coordinate on equilibria where they require only few of

  18. Young Football Players Tackle Greatest Concussion Risk At Practice

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_160579.html Young Football Players Tackle Greatest Concussion Risk at Practice But ... Children under the age of 14 who play football are at risk of concussions, and a small ...

  19. Physical profiles of elite male field hockey and soccer players ...

    African Journals Online (AJOL)

    Physical profiles of elite male field hockey and soccer players - application to sport-specific tests. ... South African Journal of Sports Medicine ... of field tests for hockey and soccer for the purposes of talent identification and training prescription.

  20. Intermittent Testing and Training for High-Level Football Players

    DEFF Research Database (Denmark)

    Ingebrigtsen, Jørgen

    Football is the most popular sport in the world, played by over 400 million men and women. In addition to the wide range of sport-specific technical and tactical skills needed, several physical components have been shown to be necessary to perform at a high level. The present PhD thesis is based...... on four articles that focus on physical testing and training for elite and sub-elite football players.The first article (Study I) aims to identify and establish aerobic capacities and anthropometric characteristics of elite female football players with the use of laboratory tests, and to examine whether...... with other field tests the Yo-Yo IR2 has become an important tool for monitoring the physical fitness of football players. However, the burden of testing, for players (physically and mentally) and the coaching staff (time consuming), is large and there is a probability that the tests may contain overlapping...

  1. Comparative Study on Anxiety between Student Players of Different ...

    African Journals Online (AJOL)

    user

    cognitive and behavioral components. The root .... on the induced stress on the heart rate of players before the game and physical work load and ... analysis rather than to assume the relationships based on previous theories per se (Reilly and.

  2. Research on Dietary Nutrition Supplement of Taekwondo Players

    Directory of Open Access Journals (Sweden)

    Shuqun Qu

    2014-10-01

    Full Text Available To comprehend the characteristics of Taekwondo and the problems lying in the nutrient and dietary structure of Taekwondo players through this study and then formulate a scientific and reasonable structure in nutrient and dietary for Taekwondo players, in order to improve their athletic ability in the meantime of improving their physical quality. To comprehend energy consumption characteristics of Taekwondo and current situation of nutrient and dietary structure of Taekwondo players through methods of literature collection and comparative research and then come up with a scientific and reasonable structure in nutrient and dietary. A reasonable nutrient and dietary structure can not only improve physical function and guarantee a normal internal metabolism of Taekwondo players, but also can effectively improve their athletic ability and improve their performance in competition.

  3. Tackle-injury epidemiology in koshuis rugby players at Stellenbosch ...

    African Journals Online (AJOL)

    Little is known about the epidemiology of tackle injuries in koshuis rugby players. Objectives. To (i) calculate ... Department of Sport Science, Stellenbosch University, Stellenbosch, South Africa. Corresponding ..... prevention. Int J Sports Sci ...

  4. Hypoconnectivity and Hyperfrontality in Retired American Football Players

    Science.gov (United States)

    Hampshire, Adam; MacDonald, Alex; Owen, Adrian M.

    2013-10-01

    Recent research has raised concerns about the long-term neurological consequences of repetitive concussive and sub-concussive injuries in professional players of American Football. Despite this interest, the neural and psychological status of retired players remains unknown. Here, we evaluated the performances and brain activation patterns of retired National Football League players (NFL alumni) relative to controls using an fMRI-optimised neuropsychological test of executive function. Behaviourally, the NFL alumni showed only modest performance deficits on the executive task. By contrast, they showed pronounced hyperactivation and hypoconnectivity of the dorsolateral frontal and frontopolar cortices. Critically, abnormal frontal-lobe function was correlated with the number of times that NFL alumni reported having been removed from play after head injury and was evident in individual players. These results support the hypothesis that NFL alumni have a heightened probability of developing executive dysfunction and suggest that fMRI provides the most sensitive biomarker of the underlying neural abnormality.

  5. Soccer players' fitting perception of different upper boot materials.

    Science.gov (United States)

    Olaso Melis, J C; Priego Quesada, J I; Lucas-Cuevas, A G; González García, J C; Puigcerver Palau, S

    2016-07-01

    The present study assessed the influence of upper boot materials on fitting perception. Twenty players tested three soccer boots only differing in the upper boot material (natural calf leather, natural kangaroo leather and synthetic leather). Players reported fitting perception and preference on specific foot areas using a perceived fitting scale. Ratings were averaged for every foot area. Repeated measures ANOVA was used to analyze the differences between boots. The kangaroo leather boots were perceived tighter and closer to the preferred fitting in general fitting, metatarsals area and instep area. The synthetic leather boots were perceived as the loosest and as the most distant boot from the preferred fitting in medial front area and instep area. In conclusion, the type of upper boot material influences the fitting perception of soccer players. The kangaroo leather was the material whose fitting was perceived closest to the players fitting preference.

  6. How Players Lose Interest in Playing a Game

    DEFF Research Database (Denmark)

    Bauckhage, Christian; Kersting, Kristian; Sifa, Rafet

    2012-01-01

    Analyzing telemetry data of player behavior in computer games is a topic of increasing interest for industry and research, alike. When applied to game telemetry data, pattern recognition and statistical analysis provide valuable business intelligence tools for game development. An important problem...... introduce methods from random process theory into game data mining in order to draw inferences about player engagement. Given large samples (over 250,000 players) of behavioral telemetry data from five different action-adventure and shooter games, we extract information as to how long individual players...... have played these games and apply techniques from lifetime analysis to identify common patterns. In all five cases, we find that the Weibull distribution gives a good account of the statistics of total playing times. This implies that an average player’s interest in playing one of the games considered...

  7. Development of speed qualities of skilled water-polo players

    Directory of Open Access Journals (Sweden)

    Ostrovsky M.V.

    2010-02-01

    Full Text Available Swimming preparation of water-polo players is the basic factor of victory of command. There are a few variants of development of speed swimming preparation. The effective pedagogical mean of stimulation of speed qualities is brief exercises at the end of employments after long aerobic work. The purpose of work is an improvement of method of speed preparation of skilled water-polo players. 26 skilled water-polo players (MS -14 and KMS - 12 took part in an experiment in age from 21 to 32 years. The results of correction of structure of training employment are in-process presented in micro cycle. They are directed on the improvement of speed qualities of water-polo players.

  8. Diagnosis Aerobic Component of Operational Preparedness Skill Players

    Directory of Open Access Journals (Sweden)

    Vasylyuk Vasyl

    2017-01-01

    Full Text Available Considerable importance for the control system, selection and orientation of the players on the stage long-term preparation plays a selection of effective methods of testing the various components of functional fitness athlete for timely, objective information about the players. The use of reliable scientific methods of effective monitoring of the athlete contributes to the further improvement of skills, increase athletic achievements. The purpose of this article is to describe and summarize modern methods of diagnosis and development of aerobic component of operational preparedness players qualifications. This article describes methods that actively and effectively used in leading European football teams. Specifically Yo-Yo test, test Shuttle (beep-test, Bangsbo test, test Hoff-Helgerud, test Conconi, Wingate-test. These tests have a high level of reliability and security mechanisms for assessing aerobic power players.

  9. Preferred Leadership Behaviours of Male and Female Badminton Players

    Directory of Open Access Journals (Sweden)

    Rajkumar S HARMA

    2015-06-01

    Full Text Available Pr eferences for specific coaching behaviours of male and female Badminton players were measured by the modified and revised Leadership Scale for Sport. Eighty two (Males=61, Females=21 badminton players were selected from amongst the players representing th eir respective university teams in East - zone Inter - university Badminton (Men/Women tournaments held at Bilaspur (CG. The present investigation noted the statistically significant differences among East - zone Inter - university level male as well as female B adminton player’s preferences for specific coaching behaviour. Differences were not observed between male and female badminton players in all the dimensions together of specific coaching behaviours of preferred leadership. It is recommended that coaches a lign their coaching style to meet the needs of their teams.

  10. A measure for the batting performance of cricket players : research ...

    African Journals Online (AJOL)

    Abstract. A single measure that can be used to assess the performance of batsmen ... a formula for batting performance and a classification table for Test players. Keywords: Batting performance, Consistency, Cricket, Present form of a batsman ...

  11. Real-Time Game Adaptation for Optimizing Player Satisfaction

    DEFF Research Database (Denmark)

    Yannakakis, Georgios; Hallam, John

    2009-01-01

    A methodology for optimizing player satisfaction in games on the "playware" physical interactive platform is demonstrated in this paper. Previously constructed artificial neural network user models, reported in the literature, map individual playing characteristics to reported entertainment...

  12. Extensive monitoring through multiple blood samples in professional soccer players

    DEFF Research Database (Denmark)

    Heisterberg, Mette F; Fahrenkrug, Jan; Krustrup, Peter

    2013-01-01

    ABSTRACT: The aim of this study was to make a comprehensive gathering of consecutive detailed blood samples from professional soccer players, and to analyze different blood parameters in relation to seasonal changes in training and match exposure.Blood samples were collected five times during a six...... months period and analyzed for 37 variables in 27 professional soccer players from the best Danish league. Additionally, players were tested for body composition, VO2max and physical performance by the Yo-Yo intermittent endurance sub-max test (IE2).Multiple variations in blood parameters occurred during...... of the season. Leucocytes decreased with increased physical training. Lymphocytes decreased at the end of the season. VO2max decreased towards the end of the season whereas no significant changes were observed in the IE2 test.The regular blood samples from elite soccer players reveal significant changes...

  13. A characterization of 2-player mechanisms for scheduling

    CERN Document Server

    Christodoulou, George; Vidali, Angelina

    2008-01-01

    We study the mechanism design problem of scheduling unrelated machines and we completely characterize the decisive truthful mechanisms for two players when the domain contains both positive and negative values. We show that the class of truthful mechanisms is very limited: A decisive truthful mechanism partitions the tasks into groups so that the tasks in each group are allocated independently of the other groups. Tasks in a group of size at least two are allocated by an affine minimizer and tasks in singleton groups by a task-independent mechanism. This characterization is about all truthful mechanisms, including those with unbounded approximation ratio. A direct consequence of this approach is that the approximation ratio of mechanisms for two players is 2, even for two tasks. In fact, it follows that for two players, VCG is the unique algorithm with optimal approximation 2. This characterization provides some support that any decisive truthful mechanism (for 3 or more players) partitions the tasks into gro...

  14. Ranking benchmarks of top 100 players in men's professional tennis.

    Science.gov (United States)

    Reid, Machar; Morris, Craig

    2013-01-01

    In men's professional tennis, players aspire to hold the top ranking position. On the way to the top spot, reaching the top 100 can be seen as a significant career milestone. National Federations undertake extensive efforts to assist their players to reach the top 100. However, objective data considering reasonable ranking yardsticks for top 100 success in men's professional tennis are lacking. Therefore, it is difficult for National Federations and those involved in player development to give empirical programming advice to young players. By taking a closer look at the ranking history of professional male tennis players, this article tries to provide those involved in player development a more objective basis for decision-making. The 100 names, countries, birthdates and ranking histories of the top 100 players listed in the Association of Tennis Professionals (ATP) at 31 December 2009 were recorded from websites in the public domain. Descriptive statistics were reported for the ranking milestones of interest. Results confirmed the merits of the International Tennis Federation's junior tour with 91% of the top 100 professionals earning a junior ranking, the mean peak of which was 94.1, s=148.9. On average, top 100 professionals achieved their best junior rankings and earned their first ATP point at similar ages, suggesting that players compete on both the junior and professional tours during their transition. Once professionally ranked, players took an average 4.5, s=2.1 years to reach the ATP top 100 at the mean age of 21.5, s=2.6 years, which contrasts with the mean current age of the top 100 of 26.8, s=3.2. The best professional rankings of players born in 1982 or earlier were positively related to the ages at which players earned their first ATP point and then entered the top 100, suggesting that the ages associated with these ranking milestones may have some forecasting potential. Future work should focus on the change in top 100 demographics over time as well

  15. Frictionless Racquetball?

    CERN Document Server

    Brashear, Robert; Santos, Carolina; Kagan, Mikhail

    2013-01-01

    When a ball hits a surface, does the angle of reflection always equal the angle of incidence? Not at all! Depending on the interplay of the ball's spin and speed and the force of friction, the ball's behavior after the bounce may differ dramatically. Surely some experienced racquetball, ping-pong, pool, tennis and players alike take advantage of this fact. A physics teacher, in turn, can take advantage of the fact that by observing the bounce of a ball her students can determine the coefficient of friction between the ball and the floor. All it takes is a typical video (smartphone) camera and some standard software However, this seemingly straightforward method may lead to surprises. If one wants to double check the value of the coefficient of friction by observing the second, third etc. bounces, one may find the the force of friction "does not turn on". We investigate why this happens, state a hypothesis and run some testing experiments. Teachers who would like to include an illustration of the scientific cy...

  16. Upper extremity sensorimotor control among collegiate football players.

    Science.gov (United States)

    Laudner, Kevin G

    2012-03-01

    Injuries stemming from shoulder instability are very common among athletes participating in contact sports, such as football. Previous research has shown that increased laxity negatively affects the function of the sensorimotor system potentially leading to a pathological cycle of shoulder dysfunction. Currently, there are no data detailing such effects among football players. Therefore, the purpose of this study was to examine the differences in upper extremity sensorimotor control among football players compared with that of a control group. Forty-five collegiate football players and 70 male control subjects with no previous experience in contact sports participated. All the subjects had no recent history of upper extremity injury. Each subject performed three 30-second upper extremity balance trials on each arm. The balance trials were conducted in a single-arm push-up position with the test arm in the center of a force platform and the subjects' feet on a labile device. The trials were averaged, and the differences in radial area deviation between groups were analyzed using separate 1-way analyses of variance (p football players showed significantly more radial area deviation of the dominant (0.41 ± 1.23 cm2, p = 0.02) and nondominant arms (0.47 ± 1.63 cm2, p = 0.03) when compared with the control group. These results suggest that football players may have decreased sensorimotor control of the upper extremity compared with individuals with no contact sport experience. The decreased upper extremity sensorimotor control among the football players may be because of the frequent impacts accumulated during football participation. Football players may benefit from exercises that target the sensorimotor system. These findings may also be beneficial in the evaluation and treatment of various upper extremity injuries among football players.

  17. Analysis of the Motor Activities of Professional Polish Soccer Players

    Directory of Open Access Journals (Sweden)

    Andrzejewski Marcin

    2016-12-01

    Full Text Available Introduction. The aims of the present study were to determine the activity profiles of a large sample of Polish Premier League soccer players during elite-standard soccer matches depending on their position on the pitch and the intensity range of physical activity. Material and methods. The study sample comprised 1,178 players in 5 outfield positions: external defenders (ED, n = 289, central defenders (CD, n = 307, central midfield players (CM, n = 327, external midfield players (EM, n = 152, and forwards (F, n = 103. Altogether, 81 Polish League games held during four domestic seasons (2010-2011, 2011-2012, 2012-2013, and 2013-2014 were used in the analysis. A semi-automatic computerised player tracking system (Amisco Pro®, version 1.0.2, Nice, France was applied to create the match activity profiles of the teams. Results. The results of statistical analysis revealed that the average total distance covered by all the players (n = 1,178 was 11,313 ± 852 m. With respect to the players’ position on the pitch, the central midfielders travelled the longest average distance (11,894 ± 765 m during the game. The longest distance was covered in the V1 intensity range (62%, followed by V2 (15%, V3 (10%, V4 (8%, V5 (3%, and V6 (2%. Conclusions. The objective of this study was to verify the differences among playing positions and to quantify the demands placed on elite Polish soccer players in each individual position during match play. While analysing elite-level match play in terms of the overall distance covered in different categories of intensity, we found a number of statistically significant differences between different playing positions. The data presented in this study can be regarded as norms for elite soccer players, serve for present and future comparison, and represent the scientific basis for developing position-specific conditioning/training protocols in soccer.

  18. Biomechanics of heading a soccer ball: implications for player safety.

    Science.gov (United States)

    Babbs, C F

    2001-08-08

    To better understand the risk and safety of heading a soccer ball, the author created a set of simple mathematical models based upon Newton's second law of motion to describe the physics of heading. These models describe the player, the ball, the flight of the ball before impact, the motion of the head and ball during impact, and the effects of all of these upon the intensity and the duration of acceleration of the head. The calculated head accelerations were compared to those during presumably safe daily activities of jumping, dancing, and head nodding and also were related to established criteria for serious head injury from the motor vehicle crash literature. The results suggest heading is usually safe but occasionally dangerous, depending on key characteristics of both the player and the ball. Safety is greatly improved when players head the ball with greater effective body mass, which is determined by a player"s size, strength, and technique. Smaller youth players, because of their lesser body mass, are more at risk of potentially dangerous headers than are adults, even when using current youth size balls. Lower ball inflation pressure reduces risk of dangerous head accelerations. Lower pressure balls also have greater "touch" and "playability", measured in terms of contact time and contact area between foot and ball during a kick. Focus on teaching proper technique, the re-design of age-appropriate balls for young players with reduced weight and inflation pressure, and avoidance of head contact with fast, rising balls kicked at close range can substantially reduce risk of subtle brain injury in players who head soccer balls.

  19. Implementation of Mobile Streaming Media Player Based on BREW

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-rong; LIU Zhao

    2006-01-01

    Nowadays mobile streaming service through cell phone is becoming the highlight of new value-added mobile services. Based on the present CDMA1x wireless data network and Binary Runtime Environment for Wireless (BREW) platform, adopting compression technologies of H.264 and QCP, a set of streaming media players are designed and implemented, and the principle, structure, key technologies and performance analysis of this system are introduced. This player works well in practice.

  20. The strategy of players on the European gas market

    Energy Technology Data Exchange (ETDEWEB)

    Lecarpentier, A

    2006-07-01

    One result of opening up the European gas market to competition has been to increase the number and diversity of the players involved, whether producers, suppliers or electric utilities. However, while the gas on offer is still controlled by a handful of market players given the increasing importance of state-owned companies from exporting countries outside Europe, the downstream gas sector continues to show a strong concentration of incumbent operators seeking a dominant position in the supply of gas. (author)

  1. An Analysis of Futsal Players' Self-Esteem Levels

    Science.gov (United States)

    Kocak, Mehmet

    2015-01-01

    The purpose of this study is to investigate the self-esteem levels of futsal players according to certain variables. The samples of the study constituted 119 females and 96 males; a total of 215 players with an average age of 21.57 ± 2.20 years. The research was carried out with the end of "Rosenberg self-esteem Scale" developed by…

  2. EMOTIONAL INTELLIGENCE AMONG FEMALE BASEBALL PLAYERS: A PSYCHOLOGICAL PROBE

    Directory of Open Access Journals (Sweden)

    Dalwinder Singh

    2015-09-01

    Full Text Available Purpose : The present study was conducted to determine the emotional intelligence among Indian female baseball players. Material : For the purpose of present study, two hundred (N=200 senior national female baseball players were selected through purposive sampling technique from different regions of India. They were selected from four different regions: A (North region baseball players=50, B (East region baseball players=50, C (West region baseball players=50 and D (South region baseball players=50. To collect the required data for the present study, the questionnaire developed by Hyde et al. (2001 on emotional intelligence was administered. One Way Analysis of Variance (ANOVA was employed to compare the entire regions. Where ‘F’ values were found significant, LSD (Least Significant Difference Post-hoc test was applied to find out the direction and degree of difference. The level of significance was set at 0.05. Results : Significant differences were observed among North, East, West and South regions female baseball players on the sub-parameters; empathy, self-development, value orientation and on the parameter Emotional Intelligence (Total. No significant differences were noticed on the sub-parameters; self-awareness, self-motivation, emotional stability, managing relations, integrity, commitment and altruistic behaviour. Conclusion: The outcome of results might be due to the fact that East region female baseball players are able to pay attention to the worries and concerns of others, can listen to someone without the urge to say something, can stay focused under pressure, are able to handle multiple demands and able to identify and separate their emotions.

  3. A Musculoskeletal Profile of Elite Female Soccer Players

    OpenAIRE

    Chiaia, Theresa A.; Maschi, Robert A.; Stuhr, Robyn M.; Rogers, Jennifer R.; Sheridan, Monique A.; Callahan, Lisa R.; Hannafin, Jo A.

    2009-01-01

    The purpose of this study is to identify lower-extremity (LE) musculoskeletal characteristics of elite female soccer players and to determine whether differences between dominant and nondominant extremities exist with respect to strength, flexibility, and range of motion. Physical data were collected from 26 female professional soccer players. Core control, hip and knee passive range of motion (PROM), LE flexibility, hip abductor strength, and dynamic functional alignment were assessed for ea...

  4. An Analysis of Futsal Players' Self-Esteem Levels

    Science.gov (United States)

    Kocak, Mehmet

    2015-01-01

    The purpose of this study is to investigate the self-esteem levels of futsal players according to certain variables. The samples of the study constituted 119 females and 96 males; a total of 215 players with an average age of 21.57 ± 2.20 years. The research was carried out with the end of "Rosenberg self-esteem Scale" developed by…

  5. Analyzing online game players: from materialism and motivation to attitude.

    Science.gov (United States)

    Chang, Ju-Hui; Zhang, Hongxia

    2008-12-01

    The online game market has been growing rapidly and has received an increasing amount of attention in recent years. The results of a survey conducted in China to explore online game players' attitude formation reveal that (a) the online game player's level of materialism positively influences the motivation for playing, (b) motivation positively influences attitude toward online games, and (c) motivation fully mediates the effects of materialism on attitude.

  6. Return to Sport and Performance After Microfracture in the Knees of National Basketball Association Players

    OpenAIRE

    Harris, Joshua D.; David M. Walton; Erickson, Brandon J.; Verma, Nikhil N.; Abrams, Geoffrey D.; Bush-Joseph, Charles A.; Bach, Bernard R.; Cole, Brian J.

    2013-01-01

    Background: Use of microfracture in the knees of National Basketball Association (NBA) players is controversial. Hypotheses: (1) There would be a high rate of return to sport (RTS) in NBA players following microfracture, (2) players would RTS the season following surgery, (3) preoperative player performance would not be significantly different on RTS, and (4) there would be no significant difference in RTS rate or postoperative performance in players undergoing microfracture in comparison wit...

  7. Quantitative evaluation of trunk muscle strength in wheelchair basketball players

    Directory of Open Access Journals (Sweden)

    Sileno da Silva Santos

    2016-06-01

    Full Text Available Abstract Trunk muscle strength affects trunk controlling playing an important role in performance and to define the classes of wheelchair basketball players. Trunk control capacity differs among players and quantitative assessments of trunk muscle strength have not been investigated. The aim of this study was to identify and correlate quantitative measures of trunk muscle strength with the wheelchair basketball players' classification. Forty-two male wheelchair basketball players with spinal cord injury, amputation, post-poliomyelitis sequelae, and cerebral palsy had their trunk extension and flexion strength evaluated with isokinetic dynamometer. The classes 1.0, 2.0, 3.0, and 4.0 were considered for statistical analysis. Comparison of trunk muscle strength differed significantly between classes: 1.0 and 3.0; 1.0 and 4.0; 2.0 and 3.0; and 2.0 and 4.0. High correlation was found between the trunk muscle strength and players' classes. The findings of the present study showed a strong correlation of trunk muscle strength and wheelchair basketball classes being able to distinguish players in their classes. However, this quantitative method of evaluation of the trunk muscle strength cannot be solely used to make a decision on the full trunk control.

  8. N-player quantum games in an EPR setting

    CERN Document Server

    Chappell, James M; Abbott, Derek

    2012-01-01

    The $N$-player quantum game is analyzed in the context of an Einstein-Podolsky-Rosen (EPR) experiment. In this setting, a player's strategies are not unitary transformations as in alternate quantum game-theoretic frameworks, but a classical choice between two directions along which spin or polarization measurements are made. The players' strategies thus remain identical to their strategies in the mixed-strategy version of the classical game. In the EPR setting the quantum game reduces itself to the corresponding classical game when the shared quantum state reaches zero entanglement. We find the relations for the probability distribution for $N$-qubit GHZ and W-type states, subject to general measurement directions, from which the expressions for the mixed Nash equilibrium and the payoffs are determined. Players' payoffs are then defined with linear functions so that common two-player games can be easily extended to the $N$-player case and permit analytic expressions for the Nash equilibrium. As a specific exa...

  9. Cavum Septum Pellucidum in Retired American Pro-Football Players.

    Science.gov (United States)

    Gardner, Raquel C; Hess, Christopher P; Brus-Ramer, Marcel; Possin, Katherine L; Cohn-Sheehy, Brendan I; Kramer, Joel H; Berger, Mitchel S; Yaffe, Kristine; Miller, Bruce; Rabinovici, Gil D

    2016-01-01

    Previous studies report that cavum septum pellucidum (CSP) is frequent among athletes with a history of repeated traumatic brain injury (TBI), such as boxers. Few studies of CSP in athletes, however, have assessed detailed features of the septum pellucidum in a case-control fashion. This is important because prevalence of CSP in the general population varies widely (2% to 85%) between studies. Further, rates of CSP among American pro-football players have not been described previously. We sought to characterize MRI features of the septum pellucidum in a series of retired pro-football players with a history of repeated concussive/subconcussive head traumas compared with controls. We retrospectively assessed retired American pro-football players presenting to our memory clinic with cognitive/behavioral symptoms in whom structural MRI was available with slice thickness ≤2 mm (n=17). Each player was matched to a memory clinic control patient with no history of TBI. Scans were interpreted by raters blinded to clinical information and TBI/football history, who measured CSP grade (0-absent, 1-equivocal, 2-mild, 3-moderate, 4-severe) and length according to a standard protocol. Sixteen of 17 (94%) players had a CSP graded ≥2 compared with 3 of 17 (18%) controls. CSP was significantly higher grade (pfootball players compared with patients without a history of TBI.

  10. Risk Factors for Injuries in Professional Football Players.

    Science.gov (United States)

    Haxhiu, Bekim; Murtezani, Ardiana; Zahiti, Bedri; Shalaj, Ismet; Sllamniku, Sabit

    2015-01-01

    The aim of this study was to identify risk factors related to the occurrence of injuries in football players. The study included 216 football players from 12 teams in the elite football league. Football-related injury data were collected prospectively during the 2012/2013 competitive season. At baseline the following information was collected for the players: anthropometric measurements (weight, height, BMI, subcutaneous skinfolds), playing experience, injury history, physical fitness performance test (agility run), peak oxygen uptake. The incidence, type and severity of injuries and training and game exposure times were prospectively documented for each player. Most of the players (n = 155, 71.7%) sustained the injures during the study period. The overall injury incidence during the regular season was 6.3 injuries per 1000 athlete-exposures (95% confidence interval, 4.31-9.67). Multivariate logistic regression analysis showed that playing experience (odds ratio [OR] = 0.44; 95% CI = 0.32-0.61, p football for more than 1 month, with knee injuries (25.42%) being the most severe type. The risk factors that increase injury rates in football players were previous injury, higher age and years of playing. Future research should include adequate rehabilitation program to reduce the risk of injuries.

  11. Early-onset arthritis in retired National Football League players.

    Science.gov (United States)

    Golightly, Yvonne M; Marshall, Stephen W; Callahan, Leigh F; Guskiewicz, Kevin

    2009-09-01

    Injury has been identified as a potential risk factor for osteoarthritis. However, no previous study has addressed playing-career injuries and subsequent osteoarthritis in a large sample of former athletes. The purpose of this study was to describe the prevalence and determinants of arthritis and osteoarthritis in retired professional football players. Self-reported arthritis prevalence and retrospectively-recalled injury history were examined in a cross-sectional survey of 2,538 retired football players. Football players reported a high incidence of injury from their professional playing days (52.8% reported knee injuries, 74.1% reported ligament/tendon injuries, and 14.2% reported anterior cruciate ligament tears). For those under 60 years, 40.6% of retired NFL players reported arthritis, compared with 11.7% of U.S. males (prevalence ratio = 3.5, 95% CI: 3.3 to 3.7). Within the retired NFL player cohort, osteoarthritis was more prevalent in those with a history of knee injury (prevalence ratio = 1.7, 95% CI: 1.5 to 1.9) and ligament/tendon injury (prevalence ratio = 1.6, 95% CI: 1.4 to 1.9). In males under the age of 60, arthritis is over 3 times more prevalent in retired NFL players than in the general U.S. population. This excess of early-onset arthritis may be due to the high incidence of injury in football.

  12. [Eating habits of a group of professional volleyball players].

    Science.gov (United States)

    Gacek, Maria

    2011-01-01

    The aim of the research was an analysis of the eating habits of professional volleyball players according to their sex and age. The research has been carried out on a group of 210 men players and women players at the age of 13-25, representatives of sports clubs in Ostrołeka, Myślenice, Bydgoszcz and Warszawa. The research has revealed a limited realisation of rational diets by both men and women players. The most common mistakes made by them include a smaller number of meals during the day than recommended (especially among men), taking up training on empty stomach and insufficient frequency of consumption of dairy products, fish, vegetables and fruit. The research has also revealed excessive consumption of sweets, sweet sparkling drinks and fast food (mainly among men). The examined players to some extent only apply regular strategies of rehydration of their organisms. A high percentage of them do not pay attention to supplementation of liquids after an effort or they drink a lot of liquids at one time. The most frequently chosen drinks were mineral water and isotonic drinks. Supplementation was applied by a small percentage of the players, mainly men, who most often chose vitamins, Izostar, creatine, L-carnitine and HMB.

  13. Caffeine supplementation and reactive agility in elite youth soccer players.

    Science.gov (United States)

    Jordan, J Bradley; Korgaokar, Ajit; Farley, Richard S; Coons, John M; Caputo, Jennifer L

    2014-05-01

    This study examined the effects of caffeine supplementation (6 mg·kg-1) on performance of a reactive agility test (RAT) in 17 elite, male, youth (M = 14 y) soccer players. Using a double-blind, repeated-measures design, players completed 4 days of testing on the RAT after a standardized warm-up. On day 1, anthropometric measurements were taken and players were accommodated to the RAT. On day 2, baseline performance was established. Caffeine or placebo conditions were randomly assigned on day 3 and the condition was reversed on day 4. Players completed 3 randomized trials of the RAT on days 2, 3, and 4 with at least 1 trial to the players' dominant and nondominant sides. There were no significant differences among conditions in reaction time (RT) to the dominant side, heart rates at any point of measurement, or ratings of perceived exertion (RPE) after completion of the warm-up. Caffeine produced faster RT to the nondominant side (P = .041) and higher RPE at the conclusion of the RAT (P = .013). The effect on the total time (TT) to complete the agility test to the nondominant side approached significance (P = .051). Sprint time and TT to either side did not differ. Caffeine supplementation may provide ergogenic benefit to elite, male, youth soccer players.

  14. ANTROPOMETRIC CHARACTERISTICS AND MOTOR SKILLS OF YOUNG MONTENEGRO BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Milovan Ljubojević

    2012-09-01

    Full Text Available Testing and measurement in basketball is basically supposed to help in the initial evaluation and interpretation of features and capabilities of players that are important for their activity. The main objective of testing is the possibility of obtaining information about the three general indicators in basketball practice, namely: the level of current results in certain ability, the pace of results improvement in the ability and stability of the results in tests of ability. For this purpose, testing and measurement of young basketball players, members of the Montenegro under-18 team, was carried out. The aim of this paper is to present the basic features and capabilities of young basketball players of Montenegro and their comparison with some other teams. Variables from anthropometry space were measured: body height, arm span, reach height, body mass. Motor skills were observed by variables: the last squat, thrust from a flat bench, rear thrust, lying-sitting for 30 seconds, sargent test, long jump, 20 yard test, kamikaze, špagat, sitting bow. Based on the processed results it can be concluded that the motor skills of our young players, tested in this study, are at the level of the young players of other representations. The results will be of great help to coaches who work with these players.

  15. ARM 7 BASED MP3 PLAYER

    Directory of Open Access Journals (Sweden)

    Ashiq V Mehta

    2014-02-01

    Full Text Available MP3 is a patented encoding format for digital audio which uses a form of lossy data compression. It is a common audio format for consumer audio streaming or storage, as well as a de facto standard of digital audio compression for the transfer and playback of music on most digital audio players. Since the MPEG-1 Layer III encoding technology is nowadays widely used it might be interesting to gain knowledge of how this powerful compression/decompression scheme actually functions. The MPEG-1 Layer III is capable of reducing the bit rate with a factor of 12 without almost any audible degradation. Arm7 lpc2148 is arm7tdmi-s core board microcontroller that uses 16/32-bit 64 pin (lqfp microcontroller no.lpc2148 from Philips (nxp.The hardware system of lpc2148 includes the necessary devices within only one mcu has such as usb, adc, dac, timer/counter, pwm, capture, i2c, spi, uart, and etc.

  16. Unexpected cellular players in Rett syndrome pathology.

    Science.gov (United States)

    Cronk, James C; Derecki, Noel C; Litvak, Vladimir; Kipnis, Jonathan

    2016-08-01

    Rett syndrome is a devastating neurodevelopmental disorder, primarily caused by mutations of methyl CpG-binding protein 2 (MeCP2). Although the genetic cause of disease was identified over a decade ago, a significant gap still remains in both our clinical and scientific understanding of its pathogenesis. Neurons are known to be primary players in pathology, with their dysfunction being the key in Rett syndrome. While studies in mice have demonstrated a clear causative - and potential therapeutic - role for neurons in Rett syndrome, recent work has suggested that other tissues also contribute significantly to progression of the disease. Indeed, Rett syndrome is known to present with several common peripheral pathologies, such as osteopenia, scoliosis, gastrointestinal problems including nutritional defects, and general growth deficit. Mouse models assessing the potential role of non-neuronal cell types have confirmed both roles in disease and potential therapeutic targets. A new picture is emerging in which neurons both initiate and drive pathology, while dysfunction of other cell types and peripheral tissues exacerbate disease, possibly amplifying further neurologic problems, and ultimately result in a positive feedback loop of progressively worsening symptoms. Here, we review what is known about neuronal and non-neuronal cell types, and discuss how this new, integrative understanding of the disease may allow for additional clinical and scientific pathways for treating and understanding Rett syndrome.

  17. METABOLIC DEMANDS OF MATCH PERFORMANCE IN YOUNG SOCCER PLAYERS

    Directory of Open Access Journals (Sweden)

    Alper Aslan

    2012-03-01

    Full Text Available The aim of the present study was to determine metabolic responses, movement patterns and distance covered at running speeds corresponding to fixed blood lactate concentrations (FBLs in young soccer players during a match play. A further aim of the study was to evaluate the relationships between FBLs, maximal oxygen consumption (VO2max and distance covered during a game. A multistage field test was administered to 32 players to determine FBLs and VO2max. Blood lactate (LA, heart rate (HR and rate of perceived exertion (RPE responses were obtained from 36 players during tournament matches filmed using six fixed cameras. Images were transferred to a computer, for calibration and synchronization. In all players, values for LA and HR were higher and RPE lower during the 1st half compared to the 2nd half of the matches (p < 0.01. Players in forward positions had higher LA levels than defenders, but HR and RPE values were similar between playing positions. Total distance and distance covered in jogging, low-moderate-high intensity running and low intensity sprint were higher during the 1st half (p < 0.01. In the 1st half, players also ran longer distances at FBLs [p<0.01; average running speed at 2mmol·L-1 (FBL2: 3.32 ± 0.31m·s-1 and average running speed at 4mmol·L-1 (FBL4: 3.91 ± 0.25m·s-1]. There was a significant difference between playing positions in distance covered at different running speeds (p < 0.05. However, when distance covered was expressed as FBLs, the players ran similar distances. In addition, relationships between FBLs and total distance covered were significant (r = 0.482 to 0.570; p < 0.01. In conclusion, these findings demonstrated that young soccer players experienced higher internal load during the 1st half of a game compared to the 2nd half. Furthermore, although movement patterns of players differed between playing positions, all players experienced a similar physiological stress throughout the game. Finally, total

  18. Norwegian Football Academy Players-Players Self-Assessed Competence, Perfectionism, Goal Orientations and Motivational Climate

    Directory of Open Access Journals (Sweden)

    Eirik Nerland

    2016-06-01

    Full Text Available Grounded in the theoretical framework of achievement goal theory and perfectionism theory, the purpose of this study was to examine how self-assessed perceived abilities covariance these variables among Norwegian football academy players. 140 adolescent football players participated, representing three football academies. Perceived competence was reported as equivalent to or better than others. Perfectionism scores showed personal standards as the highest of the dimensions of perfectionism, while perceived parental pressure was lowest. In contrast, mean task orientation and perceived mastery climate were higher than ego orientation and perceived performance climate. The correlation analysis showed that perceived competence correlated positively with personal standards. Personal standards correlated positively with the rest of the perfectionism dimensions as well as ego orientation, perceived mastery- and performance climate. Concern over mistakes was positively correlated with ego-orientation. Overall, findings suggested that personal standards correlate with perceived competence, while these variables also relate to other perfectionism dimensions, goal orientations and perceived motivational climate. Therefore, coaches should highlight the importance of high personal standards, as a potentially maladaptive function on talent development.

  19. Violent video game players and non-players differ on facial emotion recognition.

    Science.gov (United States)

    Diaz, Ruth L; Wong, Ulric; Hodgins, David C; Chiu, Carina G; Goghari, Vina M

    2016-01-01

    Violent video game playing has been associated with both positive and negative effects on cognition. We examined whether playing two or more hours of violent video games a day, compared to not playing video games, was associated with a different pattern of recognition of five facial emotions, while controlling for general perceptual and cognitive differences that might also occur. Undergraduate students were categorized as violent video game players (n = 83) or non-gamers (n = 69) and completed a facial recognition task, consisting of an emotion recognition condition and a control condition of gender recognition. Additionally, participants completed questionnaires assessing their video game and media consumption, aggression, and mood. Violent video game players recognized fearful faces both more accurately and quickly and disgusted faces less accurately than non-gamers. Desensitization to violence, constant exposure to fear and anxiety during game playing, and the habituation to unpleasant stimuli, are possible mechanisms that could explain these results. Future research should evaluate the effects of violent video game playing on emotion processing and social cognition more broadly.

  20. Monitoring for overreaching in rugby league players.

    Science.gov (United States)

    Coutts, Aaron J; Reaburn, Peter; Piva, Terrence J; Rowsell, Greg J

    2007-02-01

    The aim of this study was to identify indicators of non-functional overreaching (NFOR) in team sport athletes undertaking intensive training loads. Eighteen semi-professional rugby league players were randomly assigned into two pair matched groups. One group completed 6 weeks of normal training (NT) whilst the other group was deliberately overreached through intensified training (IT). Both groups then completed the same 7-day stepwise training load reduction taper. Multistage fitness test (MSFT) performance, VO2 (max), peak aerobic running velocity (V (max)), maximal heart rate, vertical jump, 10-s cycle sprint performance and body mass were measured pre- and post-training period and following the taper. Hormonal, haematological and immunological parameters were also measured pre-training and following weeks 2, 4 and 6 of training and post-taper. MANOVA for repeated measures with contrast analysis indicated that MSFT performance and VO2 (max) were significantly reduced in the IT group over time and condition, indicating that a state of overreaching was attained. However, the only biochemical measure that was significantly different between the IT and NT group was the glutamine to glutamate (Gln/Glu) ratio even though testosterone, testosterone to cortisol (T/C) ratio, plasma glutamate, and CK activity were significantly changed after training in both groups. Positive endurance and power performance changes were observed post-taper in the IT group confirming NFOR. These changes were associated with increases in the T/C ratio and the Gln/Glu ratio and decreases in plasma glutamate and CK activity. These results indicate that although there was no single reliable biochemical marker of NFOR in these athletes, the Gln/Glu ratio and MSFT test may be useful measures for monitoring responses to IT in team sport athletes.

  1. Prevalent morphometric vertebral fractures in professional male rugby players.

    Directory of Open Access Journals (Sweden)

    Karen Hind

    Full Text Available There is an ongoing concern about the risk of injury to the spine in professional rugby players. The objective of this study was to investigate the prevalence of vertebral fracture using vertebral fracture assessment (VFA dual energy X-ray absorptiometry (DXA imaging in professional male rugby players. Ninety five professional rugby league (n = 52 and union (n = 43 players (n = 95; age 25.9 (SD 4.3 years; BMI: 29.5 (SD 2.9 kg.m2 participated in the research. Each participant received one VFA, and one total body and lumbar spine DXA scan (GE Lunar iDXA. One hundred and twenty vertebral fractures were identified in over half of the sample by VFA. Seventy four were graded mild (grade 1, 40 moderate (grade 2 and 6 severe (grade 3. Multiple vertebral fractures (≥2 were found in 37 players (39%. There were no differences in prevalence between codes, or between forwards and backs (both 1.2 v 1.4; p>0.05. The most common sites of fracture were T8 (n = 23, T9 (n = 18 and T10 (n = 21. The mean (SD lumbar spine bone mineral density Z-score was 2.7 (1.3 indicating high player bone mass in comparison with age- and sex-matched norms. We observed a high number of vertebral fractures using DXA VFA in professional rugby players of both codes. The incidence, aetiology and consequences of vertebral fractures in professional rugby players are unclear, and warrant timely, prospective investigation.

  2. PSYCHOLOGICAL AND TACTICAL PREPA RATION OF JUNIOR TENNIS PLAYERS

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    Saša Milenković

    2007-05-01

    Full Text Available Ta king in to con si de ra tion the physi cal in vol ve ment, psychological stabi lity and tactical competence of a player in con tem po rary pro fes si o nal ten nis, it can be con cluded that ten nis players are con stantly ex po sed to ma king stre nu o us ef forts. More over, ta king in to ac co unt the system and the or ga ni za tion of to ur na ments, which in vol ve regu lar trips and thus chan ging ti me zo nes, types of the gro unds at ten nis co urts, clo sed sports halls and open ten nis to ur na ments, we can lo gi cally con clu de that psycho lo gi cal and tac ti cal pre pa ra tion of players in lo wer cat he go ri es is of gre at im por tan ce. The pro blem of this study re fers to the cho i ce of tasks gi ven to a player. Tasks are di rectly aimed at psycho lo gi cal sta bi lity which players ha ve to de ve lop be fo re the match, in the warm up pe riod and du ring the match it self. Tac ti cal com pe ten ce is of vi tal im por tan ce for each ten nis player who lo oks forward to ac hi e ving high sports re sults. In that sen se, a the o re ti cal ap pro ach to a tac tic is ne e ded, as well as a partial analysis of tac ti cal va ri a bles adаpted to players and to con di ti ons at matches.

  3. ANTHROPOMETRIC AND PHYSIOLOGICAL CHARACTERISTICS ON INDIAN INTERUNIVERSITY BASKETBALL PLAYERS

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    Shyamal Koley

    2010-08-01

    Full Text Available The purpose of this study was two-fold, firstly, to evaluate the anthropometric profile of Indian interuniversity basketball players and, secondly, to search the correlation of body mass index, % body fat, hand grip strength (right dominant and Vo2max,with other anthropometric characteristics studied. Eleven anthropometriccharacteristics, four body composition parameters, two physical and two physiological variables were measured on randomly selected 60 inter-university Indian basketball players (35 males and 25 females aged 18–25 years from Guru Nanak Dev University, Amritsar, Punjab, India with adequate controls (n = 102, 52 males and 50 females. The results indicated that male basketball players were taller (6.63% and heavier (7.31% and female basketball players were slightly taller (0.31% and lighter (3.74% than their control counterparts. One way analysis of variance showed significant (p ≤ .004 - .000 between group differences in all the variables (excepthip circumference between basketball players and controls. In basketball players, significantly positive correlations were found with BMI and other 12 variables, with percent body fat and 7 variables, with right hand grip strength and 12 variables and with Vo2max and other 9 variables, and significantly negative correlationswere found with BMI and other 1 variable (% lean body mass, with percent body fat and other 6 variables, with right hand grip strength and other 2 variables and with Vo2max with other 3 variables. The findings of the present study might be useful in future investigation on player selection, talent identification in the game of basketball and its training program development.

  4. Development of repeated sprint ability in talented youth basketball players.

    Science.gov (United States)

    te Wierike, Sanne C M; de Jong, Mark C; Tromp, Eveline J Y; Vuijk, Pieter J; Lemmink, Koen A P M; Malina, Robert M; Elferink-Gemser, Marije T; Visscher, Chris

    2014-04-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14-19 years of age (16.1 ± 1.7 years). Players were observed on 6 occasions during the 2008-09 and 2009-10 seasons. Three following basketball-specific field tests were administered on each occasion: the shuttle sprint test for RSA, the vertical jump for lower body explosive strength (power), and the interval shuttle run test for interval endurance capacity. Height and weight were measured; body composition was estimated (percent fat, lean body mass). Multilevel modeling of RSA development curve was used with 32 players (16.0 ± 1.7 years) who had 2 or more observations. The 16 players (16.1 ± 1.8 years) measured on only 1 occasion were used as a control group to evaluate the appropriateness of the model. Age, lower body explosive strength, and interval endurance capacity significantly contributed to RSA (p ≤ 0.05). Repeated sprint ability improved with age from 14 to 17 years (p ≤ 0.05) and reached a plateau at 17-19 years. Predicted RSA did not significantly differ from measured RSA in the control group (p ≥ 0.05). The results suggest a potentially important role for the training of lower body explosive strength and interval endurance capacity in the development of RSA among youth basketball players. Age-specific reference values for RSA of youth players may assist basketball coaches in setting appropriate goals for individual players.

  5. Design of Emergent and Adaptive Virtual Players in a War RTS Game

    CERN Document Server

    Gutiérrez, José A García; Fernández-Leiva, Antonio J

    2012-01-01

    Basically, in (one-player) war Real Time Strategy (wRTS) games a human player controls, in real time, an army consisting of a number of soldiers and her aim is to destroy the opponent's assets where the opponent is a virtual (i.e., non-human player controlled) player that usually consists of a pre-programmed decision-making script. These scripts have usually associated some well-known problems (e.g., predictability, non-rationality, repetitive behaviors, and sensation of artificial stupidity among others). This paper describes a method for the automatic generation of virtual players that adapt to the player skills; this is done by building initially a model of the player behavior in real time during the game, and further evolving the virtual player via this model in-between two games. The paper also shows preliminary results obtained on a one player wRTS game constructed specifically for experimentation.

  6. THE EVALUATION OF SOME PHYSICAL AND PHYSIOLOGICAL CAHARACTERISTICS OF TURKISH AND FOREIGN NATIONAL BADMINTON TEAM PLAYERS

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    Serkan REVAN

    2007-12-01

    Full Text Available The aim of this study was to evaluate of some physical and physiological characteristics of Turkish and Foreign National Badminton Team Players.The study was participated by 50 players from Turkish team (12 males and 11 females, from foreign team (13 females and 14 males. Body mass index, audio and visual reaction times, anaerobic power, body fat percentage and somatotype components of the participants were determined.While visual right hand reaction times of Turkish Male Badminton Players were better than foreign players, other physical parameters were not found as statistically significant between male player groups. While visual left hand reaction times of Turkish Female Badminton Players were better and mesomorphy values were less than foreign players, in other physical parameters a statistically significant difference could not found between female player groups.As a result, physical and physiological characteristics of Turkish and foreign badminton players were similar.

  7. Lateral Scapular Slide Test and Scapular Mobility in Volleyball Players

    Science.gov (United States)

    Ozunlu, Nihan; Tekeli, Hatice; Baltaci, Gul

    2011-01-01

    Context: The stability of the scapula in relation to the entire moving upper extremity is the key in the throwing sequence. The importance of scapular positioning in volleyball players has been well documented in the literature, but no one has compared scapular positioning between volleyball players and sedentary people. Objective: To compare measurements of scapular mobility obtained using the lateral scapular slide test between volleyball players and sedentary participants without shoulder impairments and to compare changes in scapular mobility in players according to the number of years of sport participation. Design: Cross-sectional study. Setting: University research laboratory. Patients or Other Participants: A total of 121 people at a single university volunteered. Of these, 67 were sedentary (age = 24.3 ± 2.34 years, height = 1.69 ± 0.09 m, mass = 65.1 ± 11.91 kg); 54 were volleyball players from 4 professional teams and were separated into 2 groups according to their years of sport participation. The first group was named young players (n = 31; age = 17.7 ± 2.58 years, height = 1.83 ± 0.10 m, mass = 68.3 ± 12.21 kg, sport participation ≤ 9 years), and the second group was named old players (n = 23; age = 26.9 ± 3.39 years, height = 1.95 ± 4.38 m, mass = 90.7 ± 5.75 kg, sport participation ≥ 10 years). Main Outcome Measure(s): Study participants completed a rating scale for pain and a questionnaire about demographic and shoulder problems. One assessor performed the lateral scapular slide test and additional flexibility measurements around the shoulder girdle. Flexibility (external rotation, internal rotation) and scapular position (1, 2, 3) were compared among groups (young players, old players, sedentary people) and between sides (dominant, nondominant). Results: In sedentary participants, we found differences for position 1 (t66 = 3.327, P = .002), position 2 (t66 = 2.491, P = .004), position 3 (t66 = 2.512, P = .006), and internal rotation

  8. Concussion among female middle-school soccer players.

    Science.gov (United States)

    O'Kane, John W; Spieker, Amy; Levy, Marni R; Neradilek, Moni; Polissar, Nayak L; Schiff, Melissa A

    2014-03-01

    Despite recent increased awareness about sports concussions, little research has evaluated concussions among middle-school athletes. To evaluate the frequency and duration of concussions in female youth soccer players and to determine if concussions result in stopping play and seeking medical care. Prospective cohort study from March 2008 through May 2012 among 4 soccer clubs from the Puget Sound region of Washington State, involving 351 elite female soccer players, aged 11 to 14 years, from 33 randomly selected youth soccer teams. Of the players contacted, 83.1% participated and 92.4% completed the study. Concussion cumulative incidence, incidence rate, and description of the number, type, and duration of symptoms. We inquired weekly about concussion symptoms and, if present, the symptom type and duration, the event resulting in symptom onset, and whether the player sought medical attention or played while symptomatic. Among the 351 soccer players, there were 59 concussions with 43 742 athletic exposure hours. Cumulative concussion incidence was 13.0% per season, and the incidence rate was 1.2 per 1000 athletic exposure hours (95% CI, 0.9-1.6). Symptoms lasted a median of 4.0 days (mean, 9.4 days). Heading the ball accounted for 30.5% of concussions. Players with the following symptoms had a longer recover time than players without these symptoms: light sensitivity (16.0 vs 3.0 days, P = .001), emotional lability (15.0 vs 3.5 days, P = .002), noise sensitivity (12.0 vs 3.0 days, P = .004), memory loss (9.0 vs 4.0 days, P = .04), nausea (9.0 vs 3.0 days, P = .02), and concentration problems (7.0 vs 2.0 days, P = .02). Most players (58.6%) continued to play with symptoms, with almost half (44.1%) seeking medical attention. Concussion rates in young female soccer players are greater than those reported in older age groups, and most of those concussed report playing with symptoms. Heading the ball is a frequent precipitating event. Awareness

  9. Quadriceps tendon injuries in national football league players.

    Science.gov (United States)

    Boublik, Martin; Schlegel, Theodore F; Koonce, Ryan C; Genuario, James W; Kinkartz, Jason D

    2013-08-01

    Distal quadriceps tendon tears are uncommon injuries that typically occur in patients older than 40 years of age, and they have a guarded prognosis. Predisposing factors, prodromal findings, mechanisms of injury, treatment guidelines, and recovery expectations are not well described in high-level athletes. Professional American football players with an isolated tear of the quadriceps tendon treated with timely surgical repair will return to their sport. Case series; Level of evidence, 4. Fourteen unilateral distal quadriceps tendon tears were identified in National Football League (NFL) players from 1994 to 2004. Team physicians retrospectively reviewed training room and clinic records, operative notes, and imaging studies for each of these players. Data on each player were analyzed to identify variables predicting return to play. A successful outcome was defined as returning to play in regular-season NFL games. Eccentric contraction of the quadriceps was the most common mechanism of injury, occurring in 10 players. Only 1 player had antecedent ipsilateral extensor mechanism symptoms. Eleven players had a complete rupture of the quadriceps tendon, and 3 had partial tears. There were no associated knee injuries. All ruptures were treated with surgical repair, 1 of which was delayed after failure of nonoperative treatment. Fifty percent of players returned to play in regular-season NFL games. There was a trend toward earlier draft status for those who returned to play compared with those who did not (draft round, 3.1 ± 2.5 vs. 6.0 ± 2.9, respectively; P = .073). For those who returned to play, the average number of games after injury was 40.9 (range, 12-92). Quadriceps tendon tears are rare in professional American football players, and they usually occur from eccentric load on the extensor mechanism. Prodromal symptoms and predisposing factors are usually absent. Even with timely surgical repair, there is a low rate of return to play in regular-season games. There

  10. Athletic performance outcomes following lumbar discectomy in professional basketball players.

    Science.gov (United States)

    Anakwenze, Okechukwu A; Namdari, Surena; Auerbach, Joshua D; Baldwin, Keith; Weidner, Zachary D; Lonner, Baron S; Huffman, G R; Sennett, Brian J

    2010-04-01

    Retrospective case-control study. To quantify the athletic performance profiles after lumbar discectomy (LD) in a cohort of National Basketball Association (NBA) players in comparison with a control group of matched NBA players who did not undergo LD during the same study period. LD provides symptomatic relief and improved functional outcomes in the majority of patients as assessed by validated measures such as Oswestry Disability Index, Visual Analog Scale, and Short Form-36 (SF-36). Among professional athletes, however, the goal of lumbar HNP treated by discectomy is not only to improve functional status but also, ultimately, to return the player to preinjury athletic performance levels. No study to date has compared the athletic performance profiles before and after discectomy in professional athletes. An analysis of NBA games summaries, weekly injury reports, player profiles, and press releases was performed to identify 24 NBA players who underwent LD for symptomatic lumbar HNP between 1991 and 2007. A 1:2 case: control study was performed using players without history of lumbar HNP who were matched for age, position, experience, and body mass index as control subjects (n = 48). Paired t tests were conducted on the following parameters: games played, minutes per game, points per 40 minutes, rebounds per 40 minutes, assists per 40 minutes, steals per 40 minutes, blocks per 40 minutes, and shooting percentage. For each athletic performance outcome, between-group comparisons evaluating preindex to postindex season performance were done (index season = season of surgery). In the LD group, 18 of 24 players (75%) returned to play again in the NBA, compared with 42 of 48 players (88%, P = 0.31) in the control group. One year after surgery, between-group comparisons revealed statistically significant increase in blocked shots per 40 minutes in the LD (0.18) versus control group (-0.33; P = 0.008) and a smaller decrease in rebounds per 40 minutes in the LD (-0

  11. Infectious diseases in rugby players: incidence, treatment and prevention.

    Science.gov (United States)

    Stacey, A; Atkins, B

    2000-03-01

    Participation in rugby football can expose individuals to a variety of infectious diseases both on and off the field of play. The close physical contact and trauma inherent in playing rugby facilitates the transmission of viral, bacterial and fungal pathogens between players and may also lead to the acquisition of potentially lethal infections from the environment, such as tetanus. In the past few years there have been a number of reported outbreaks of infection amongst rugby players in the medical literature. The appearance of HIV infection has focused attention on the potential for transmission of this and other blood-borne viruses such as hepatitis B and C viruses from bleeding wounds sustained on the rugby field. As a result, various expert bodies have produced guidelines on the management of players with bleeding wounds. Opportunities are now available to rugby players to play outside their own countries, including the third world. This can bring them into contact with a wide range of travel-associated infections, some of which may be life threatening. In view of the above it is clear that rugby players and those who coach and manage rugby teams require information and education on the subject of infection and its prevention, as well as access to appropriate medical care and expertise. Many of the infections seen in rugby players are preventable, e.g. by promoting hygienic facilities and conduct in changing rooms and on the field of play, by exclusion of infected players from contact with others and, in some cases, by immunisation or chemoprophylaxis. Players who present with infections should be assessed, correctly diagnosed (using laboratory investigations where appropriate) and treated, and measures should be taken to prevent spread to team-mates and other contacts while respecting the confidentiality of the individual. Any outbreaks of infection should be reported to the appropriate authorities. There is evidence to suggest that strenuous physical exercise

  12. Iliopsoas and gluteal muscles are asymmetric in tennis players but not in soccer players.

    Directory of Open Access Journals (Sweden)

    Joaquin Sanchis-Moysi

    Full Text Available PURPOSE: To determine the volume and degree of asymmetry of iliopsoas (IL and gluteal muscles (GL in tennis and soccer players. METHODS: IL and GL volumes were determined using magnetic resonance imaging (MRI in male professional tennis (TP and soccer players (SP, and in non-active control subjects (CG (n = 8, 15 and 6, respectively. RESULTS: The dominant and non-dominant IL were hypertrophied in TP (24 and 36%, respectively, P<0.05 and SP (32 and 35%, respectively, P<0.05. In TP the asymmetric hypertrophy of IL (13% greater volume in the non-dominant than in the dominant IL, P<0.01 reversed the side-to-side relationship observed in CG (4% greater volume in the dominant than in the contralateral IL, P<0.01, whilst soccer players had similar volumes in both sides (P = 0.87. The degree of side-to-side asymmetry decreased linearly from the first lumbar disc to the pubic symphysis in TP (r = -0.97, P<0.001, SP (r = -0.85, P<0.01 and CG (r = -0.76, P<0.05. The slope of the relationship was lower in SP due to a greater hypertrophy of the proximal segments of the dominant IL. Soccer and CG had similar GL volumes in both sides (P = 0.11 and P = 0.19, for the dominant and contralateral GL, respectively. GL was asymmetrically hypertrophied in TP. The non-dominant GL volume was 20% greater in TP than in CG (P<0.05, whilst TP and CG had similar dominant GL volumes (P = 0.14. CONCLUSIONS: Tennis elicits an asymmetric hypertrophy of IL and reverses the normal dominant-to-non-dominant balance observed in non-active controls, while soccer is associated to a symmetric hypertrophy of IL. Gluteal muscles are asymmetrically hypertrophied in TP, while SP display a similar size to that observed in controls. It remains to be determined whether the different patterns of IL and GL hypertrophy may influence the risk of injury.

  13. The movement characteristics of English Premiership rugby union players.

    Science.gov (United States)

    Cahill, Nicola; Lamb, Kevin; Worsfold, Paul; Headey, Roy; Murray, Stafford

    2013-01-01

    The purpose of this investigation was to quantify the movement characteristics of elite rugby union players during competitive play and identify whether position-related differences exist. Ninety-eight elite players from eight English Premiership Clubs were tracked using global positioning systems (GPS) during 44 competitive matches throughout the 2010/2011 season. Player positions were defined as: (1) backs or forwards; (2) front, second and back rows, scrum half, inside and outside backs; (3) 15 individual positions (numbers 1-15). Analysis revealed the game is predominantly played at low speeds with little distance covered 'sprinting' by either the backs (50 ± 76 m) or the forwards (37 ± 64 m). The backs travelled greater (P scrum half covered the greatest total distance during a match (7098 ± 778 m) and the front row the least (5158 ± 200 m). The back row covered the greatest distances at 'sprinting' speeds, particularly the number 8 position (77 m). These findings reflect notable differences in the movement characteristics displayed by elite rugby union players in specific positional roles, and reinforce the contemporary view that training programmes for such players ought to be structured with this in mind.

  14. Fitness Profiles of Elite Portuguese Rugby Union Players

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    Vaz Luís

    2014-07-01

    Full Text Available The aim of this study was to describe the fitness profiles of senior elite Portuguese rugby players. Forty-six senior Portuguese rugby players, classified as backs (n=22; age 26.2±2.8 and forwards (n=24; age 26.7±2.9 were assessed during physical testing sessions carried out for the Portuguese National rugby team. The body composition, maximum strength and anaerobic capacity of players are hypothesized to be important physical characteristics as successful performance in rugby is predicated on the ability to undertake skilled behaviours both quickly and whilst withstanding large forces when in contact situations. No absolute differences were found between the backs and forwards for the speed performance variables although positional differences were found across all speeds when assessed relative to body mass since the forwards were significantly heavier. Coaches and the management team can use this information for monitoring progressive improvements in the physiological capacities of rugby players. These physical characteristics of elite rugby players provide normative profiles for specific positions and should form the basis of developmental programmes for adolescents.

  15. Player guild dynamics and evolution in massively multiplayer online games.

    Science.gov (United States)

    Chen, Chien-Hsun; Sun, Chuen-Tsai; Hsieh, Jilung

    2008-06-01

    In the latest versions of massively multiplayer online games (MMOGs), developers have purposefully made guilds part of game environments. Guilds represent a powerful method for giving players a sense of online community, but there is little quantitative data on guild dynamics. To address this topic, we took advantage of a feature found in one of today's most popular MMOGs (World of Warcraft) to collect in-game data: user interfaces that players can modify and refine. In addition to collecting data on in-game player activities, we used this feature to observe and investigate how players join and leave guilds. Data were analyzed for the purpose of identifying factors that propel game-world guild dynamics and evolution. After collecting data for 641,805 avatars on 62 Taiwanese World of Warcraft game servers between February 10 and April 10, 2006, we created five guild type categories (small, large, elite, newbie, and unstable) that have different meanings in terms of in-game group dynamics. By viewing players as the most important resource affecting guild life cycles, it is possible to analyze game worlds as ecosystems consisting of evolving guilds and to study how guild life cycles reflect game world characteristics.

  16. How the Iranian Football Coaches and Players Know About Doping?

    Science.gov (United States)

    Seif Barghi, Tohid; Halabchi, Farzin; Dvorak, Jiri; Hosseinnejad, Heydar

    2015-01-01

    Background: Nowadays, doping is an intricate dilemma. Football is the nationally popular sport in Iran. On the other hand, doping is a serious health hazard sport faces today. Studies dealing with athletes’ knowledge, attitudes and behavior concerning doping in football are scarce. Objectives: Therefore, we aimed to investigate the knowledge and attitudes toward doping among the football coaches and players. Patients and Methods: In a cross sectional study, 375 participants (239 football players and 136 coaches) were studied. A specially made questionnaire was applied. In this study, football teams of different provinces of the country were selected by randomized clustered sampling and questionnaires were distributed among coaches and players. Results: Knowledge of football coaches and players in three categories of doping definitions, recognition of prohibited drugs and side effects of anabolic steroids was poor or moderate in 45.3%, 88.5% and 96.5%, respectively. Conclusions: Football players and coaches have poor knowledge about doping in Iran. Moreover, they believe in some inappropriate myths without any scientific or rational basis.It seems necessary to design a comprehensive educational program for all of the athletes and coaches in Iran. PMID:26448840

  17. Efficiently detecting outlying behavior in video-game players

    Directory of Open Access Journals (Sweden)

    Young Bin Kim

    2015-12-01

    Full Text Available In this paper, we propose a method for automatically detecting the times during which game players exhibit specific behavior, such as when players commonly show excitement, concentration, immersion, and surprise. The proposed method detects such outlying behavior based on the game players’ characteristics. These characteristics are captured non-invasively in a general game environment. In this paper, cameras were used to analyze observed data such as facial expressions and player movements. Moreover, multimodal data from the game players (i.e., data regarding adjustments to the volume and the use of the keyboard and mouse was used to analyze high-dimensional game-player data. A support vector machine was used to efficiently detect outlying behaviors. We verified the effectiveness of the proposed method using games from several genres. The recall rate of the outlying behavior pre-identified by industry experts was approximately 70%. The proposed method can also be used for feedback analysis of various interactive content provided in PC environments.

  18. Complexity of comparison of influence of players in simple games

    CERN Document Server

    Aziz, Haris

    2008-01-01

    Coalitional voting games appear in different forms in multi-agent systems, social choice and threshold logic. In this paper, the complexity of comparison of influence between players in coalitional voting games is characterized. The possible representations of simple games considered are simple games represented by winning coalitions, minimal winning coalitions, weighted voting game or a multiple weighted voting game. The influence of players is gauged from the viewpoint of basic player types, desirability relations and classical power indices such as Shapley-Shubik index, Banzhaf index, Holler index, Deegan-Packel index and Chow parameters. Among other results, it is shown that for a simple game represented by minimal winning coalitions, although it is easy to verify whether a player has zero or one voting power, computing the Banzhaf value of the player is #P-complete. Moreover, it is proved that multiple weighted voting games are the only representations for which it is NP-hard to verify whether the game i...

  19. Psychological and sport-specific characteristics of football players.

    Science.gov (United States)

    Junge, A; Dvorak, J; Rösch, D; Graf-Baumann, T; Chomiak, J; Peterson, L

    2000-01-01

    It is hypothesized that players of different levels of play might differ not only in their football skills but also in their way of playing football and with respect to psychological factors such as concentration, reaction time, or competitive anxiety. The psychological characteristics of a player might influence his way of playing football (in particular with respect to fair play) and also his risk of injury. A group of 588 football players were studied by questionnaire; additionally, reaction time tests were performed. Psychological characteristics were assessed by three established self-evaluation questionnaires: the Athletic Coping Skills Inventory, the State Competitive Anxiety Test, and the State-Trait-Anger-Expression-Inventory. Football-specific characteristics that were investigated included playing experience and positions played, style of play, number of training hours and games, as well as aspects of fair play. Reaction time was tested twice: without the influence of physical exercise and immediately after a 12-minute run. A significant reduction in reaction time was observed after physical exercise. In high-level players, the reaction time immediately after the 12-minute run was significantly shorter than it was in low-level players. The questionnaire answers given regarding fair play clearly indicated that fair play is not paid sufficient respect. The relationship between psychological characteristics and attitudes toward fair play was analyzed and discussed.

  20. Special considerations in the medical management of professional basketball players.

    Science.gov (United States)

    Steingard, S A

    1993-04-01

    The NBA basketball players are among the finest athletes in the world. That along with the increased popularity of the NBA has put a premium on the health of the players. The course of the season puts tremendous stress and strain on players. As medical illnesses occur, the physician may feel increased pressure to put the ill player back into the line-up. One cannot let the pressure for the player to return to activity interfere with good medical practice. At times, it is difficult to allow for the natural course of an illness, however, as discussed in this article, sometimes this is exactly what needs to be done. The temptation to overtreat is also seen in some team physicians. This too must be avoided. Along with proper treatment, there is the need for education of the athletes both in social interactions and in diet and life-style. Then we, as team physicians, can sit back and enjoy the performance on the court.

  1. Epidemiology of musculoskeletal injury in the tennis player.

    Science.gov (United States)

    Abrams, Geoffrey D; Renstrom, Per A; Safran, Marc R

    2012-06-01

    Tennis is a popular sport with tens of millions of players participating worldwide. This popularity was one factor leading to the reappearance of tennis as a medal sport at the 1988 Summer Olympics in Seoul, South Korea. The volume of play, combined with the physical demands of the sports, can lead to injuries of the musculoskeletal system. Overall, injury incidence and prevalence in tennis has been reported in a number of investigations. The sport creates specific demands on the musculoskeletal system, with acute injuries, such as ankle sprains, being more frequent in the lower extremity while chronic overuse injuries, such as lateral epicondylitis, are more common in the upper extremity in the recreational player and shoulder pain more common in the high-level player. This review discusses the epidemiology of injuries frequently experienced in tennis players and examines some of these injuries' correlation with the development of osteoarthritis. In addition, player-specific factors, such as age, sex, volume of play, skill level, racquet properties and grip positions as well as the effect of playing surface on the incidence and prevalence of injury is reported. Finally, recommendations on standardisation of future epidemiological studies on tennis injuries are made in order to be able to more easily compare results of future investigations.

  2. Fitness Profiles of Elite Portuguese Rugby Union Players

    Science.gov (United States)

    Vaz, Luís; Morais, Tomaz; Rocha, Henrique; James, Nic

    2014-01-01

    The aim of this study was to describe the fitness profiles of senior elite Portuguese rugby players. Forty-six senior Portuguese rugby players, classified as backs (n=22; age 26.2±2.8) and forwards (n=24; age 26.7±2.9) were assessed during physical testing sessions carried out for the Portuguese National rugby team. The body composition, maximum strength and anaerobic capacity of players are hypothesized to be important physical characteristics as successful performance in rugby is predicated on the ability to undertake skilled behaviours both quickly and whilst withstanding large forces when in contact situations. No absolute differences were found between the backs and forwards for the speed performance variables although positional differences were found across all speeds when assessed relative to body mass since the forwards were significantly heavier. Coaches and the management team can use this information for monitoring progressive improvements in the physiological capacities of rugby players. These physical characteristics of elite rugby players provide normative profiles for specific positions and should form the basis of developmental programmes for adolescents. PMID:25114750

  3. Relative age effect and selection of young basketball players

    Directory of Open Access Journals (Sweden)

    Vučković Igor

    2013-01-01

    Full Text Available Purpose of the present study was to examine whether influence of relative age effect (RAE exists or not in the selected 13 year old basketball players. Subjects were 20 basketball players (HT=177.35cm±6.73, BW=61.42kg±8.98, average age 13 years and 7 months ±.28, average experience in basketball training 4 years and 6 months ±1.15. Sample was divided in two groups: 11 players born in first half of the year and 9 players born in the second half of the year. One-way ANOVA was used in order to analyze the differences between the two groups of players in set of anthropometric variables (body height, arm span, standing reach height, body weight and percentage of body fat, motor variables (velocity of neuromuscular reaction time, vertical jump, 5 meters sprint, 10 meters sprint, 20 meters sprint, T-test, Zig-zag test, ball throw from sitting position, Sit-ups for 30 seconds and standing forward bend and one functional variable (20-M shuttle run test. Subjects do not differ in applied set of parameters, except in on variable (sit-ups for 30 seconds, p=.040. It was concluded that RAE does not exist in this sample of examinees.

  4. MEANING TO BE VOLLEYBALL PLAYER IN CAREER TRANSITION PHASE

    Directory of Open Access Journals (Sweden)

    Adriana Justino

    2016-09-01

    Full Text Available The objective of this study is to assess the meaning of being that a volleyball player for the under-19 players who are experiencing a transition in their in career. Sixteen male players aged 17 and 18 were evaluated, by being asked the triggering question “What does being a volleyball player mean to you?” The analysis of the discourses was carried out according to the procedures recommended by Miles & Huberman (2004. Four response categories resulted: psychoemotional and behavioral skills, emotions in sport, recognition and financial return, skills as an athlete/player. The athletes showed that the meaning of sport lies especially in the passion for practice, but also, in the improving of their tactics and techniques, in the development of psychoemotional and behavioral skills, in the professional recognition and, to a lesser degree, in the financial aspect. Most athletes state they intend to continue in the juvenile sports categories, therefore, understanding the meaning of this activity in their life can be the key to the elaboration of a plan of psychological preparation whose aim is to provide support to their needs in this moment of professional choice.

  5. Ιnjuries in greek amateur soccer players

    Directory of Open Access Journals (Sweden)

    GEORGIOS TSIGANOS

    2007-01-01

    Full Text Available The purpose of this study was to record retrospectivelythe epidemiology of injuries in amateur Greek soccer players. Three hundred and one (301 amateur soccer playersvoluntarily participated in the study. Participants answered aspecially-designed questionnaire that included questionsabout demographics, playing surface, division, position,hours of training plus participation, the use of stretching orprophylactic tape, the injury mechanism, the location andtype of injury. During the five years these soccer playerssustained a total of 1.745 injuries, that diagnosed by the orthopedist of the team. Most of injuries were strains (33%,overuse (27% and sprains (25%. The location of injurieswas the thigh (38 %, ankle (27% and knee (13%. Therewas a significant difference in the total number of injuriesamong soccer players with or without scoliosis (t=3.152,p. 0.05 and players that played on sand/dirt (gravel, whosustained more injuries than the players who played on artificial grass or on grass (t=3.413, p. 0.05. No differenceswere found in the other measurement parameters. The results of our study shows that spine deformities and groundsurfaces are the factors that causes more injuries in amateurGreek soccer players.

  6. A Discrete Evolutionary Model for Chess Players' Ratings

    CERN Document Server

    Fenner, Trevor; Loizou, George

    2011-01-01

    The Elo system for rating chess players, also used in other games and sports, was adopted by the World Chess Federation over four decades ago. Although not without controversy, it is accepted as generally reliable and provides a method for assessing players' strengths and ranking them in official tournaments. It is generally accepted that the distribution of players' rating data is approximately normal but, to date, no stochastic model of how the distribution might have arisen has been proposed. We propose such an evolutionary stochastic model, which models the arrival of players into the rating pool, the games they play against each other, and how the results of these games affect their ratings. Using a continuous approximation to the discrete model, we derive the distribution for players' ratings at time $t$ as a normal distribution, where the variance increases in time as a logarithmic function of $t$. We validate the model using published rating data from 2007 to 2010, showing that the parameters obtained...

  7. Adaptivity to Age, Gender, and Gaming Platform Topology in Physical Multi-Player Games

    DEFF Research Database (Denmark)

    Lund, Henrik Hautop; Friðriksson, Rafn Vídalín; Björnsson, Davíð Þór

    2012-01-01

    In games where players are competing against each other, it can be of interest to ensure that all players are challenged according to their individual skills. In order to investigate such adaptivity to the individual player in physical multi-player games, we developed a game on modular interactive...... and adults, and between male and female players. Also, results show statistically significant differences in the game interactions between different physical set-ups of the modular interactive tiles, i.e. the interaction depended on the topology of the modular tiles set-up. Changing the physical set......-up of the physical game platform changes the interaction and performance of the players....

  8. Is There Chronic Brain Damage in Retired NFL Players? Neuroradiology, Neuropsychology, and Neurology Examinations of 45 Retired Players.

    Science.gov (United States)

    Casson, Ira R; Viano, David C; Haacke, E Mark; Kou, Zhifeng; LeStrange, Danielle G

    2014-09-01

    Neuropathology and surveys of retired National Football League (NFL) players suggest that chronic brain damage is a frequent result of a career in football. There is limited information on the neurological statuses of living retired players. This study aimed to fill the gap in knowledge by conducting in-depth neurological examinations of 30- to 60-year-old retired NFL players. In-depth neurological examinations of 30- to 60-year-old retired players are unlikely to detect objective clinical abnormalities in the majority of subjects. A day-long medical examination was conducted on 45 retired NFL players, including state-of-the-art magnetic resonance imaging (MRI; susceptibility weighted imaging [SWI], diffusion tensor imaging [DTI]), comprehensive neuropsychological and neurological examinations, interviews, blood tests, and APOE (apolipoprotein E) genotyping. Level 3. Participants' histories focused on neurological and depression symptoms, exposure to football, and other factors that could affect brain function. The neurological examination included Mini-Mental State Examination (MMSE) evaluation of cognitive function and a comprehensive search for signs of dysarthria, pyramidal system dysfunction, extrapyramidal system dysfunction, and cerebellar dysfunction. The Beck Depression Inventory (BDI) and Patient Health Questionnaire (PHQ) measured depression. Neuropsychological tests included pen-and-paper and ImPACT evaluation of cognitive function. Anatomical examination SWI and DTI MRI searched for brain injuries. The results were statistically analyzed for associations with markers of exposure to football and related factors, such as body mass index (BMI), ethanol use, and APOE4 status. The retired players' ages averaged 45.6 ± 8.9 years (range, 30-60 years), and they had 6.8 ± 3.2 years (maximum, 14 years) of NFL play. They reported 6.9 ± 6.2 concussions (maximum, 25) in the NFL. The majority of retired players had normal clinical mental status and central

  9. Intermittent Testing and Training for High-Level Football Players

    DEFF Research Database (Denmark)

    Ingebrigtsen, Jørgen

    systematic differences between the playing positions can be detected. Lately, field tests have become more frequently used in football than the laboratory tests used in Study I. Study II therefore aims to assess the validity of one of them, the Yo-Yo Intermittent Recovery test level 2 (Yo-Yo IR2). Along...... with other field tests the Yo-Yo IR2 has become an important tool for monitoring the physical fitness of football players. However, the burden of testing, for players (physically and mentally) and the coaching staff (time consuming), is large and there is a probability that the tests may contain overlapping...... on the Yo-Yo IR2 test and other field- and laboratory tests of intermittent interval training performed as anaerobic speed-endurance production training is very limited for football players. Hence, this latter question is examined in Study IV.In Study I we find no differences in anthropometric...

  10. Somatotype of competitive youth soccer players from Brazil.

    Science.gov (United States)

    Fidelix, Yara Lucy; Berria, Juliane; Ferrari, Elisa Pinheiro; Ortiz, Jaelson Gonçalves; Cetolin, Tiago; Petroski, Edio Luiz

    2014-09-29

    The aim of this study was to identify the morphological configuration of youth athletes from professional soccer clubs and to verify their differences according to the tactical position on the field. Overall, 67 male players aged 15 to 17 years were evaluated. The examined anthropometric measurements included body mass, body height, skinfolds (triceps, subscapular, supraspinal and medial calf), girths (flexed and tensed arm and calf) and breadths (humerus and femur). For statistical purposes, analysis of variance and post hoc Bonferroni and Kruskal-Wallis tests were used. We concluded that goalkeepers were heavier and taller than center backs (p = 0.015 and p = 0.001), midfielders (p = 0.005 and p somatotype for defense, forward and goalkeeper positions was a balanced mesomorph. Midfield players showed ectomorphic-mesomorph characteristics. It was concluded that goalkeepers were characterized as being taller and heavier and that somatotype features of athletes were similar between positions, except for midfield players.

  11. Social dimensions of expertise in World of Warcraft players

    Directory of Open Access Journals (Sweden)

    Mark Chen

    2009-03-01

    Full Text Available Expertise development in the massively multiplayer online game World of Warcraft (Blizzard Entertainment, 2004 depends greatly on a player's use of social skills to gain access to expert player groups and accrue social and cultural capital. Drawn from ethnographic research, this paper maps out various forms of expert practice and highlights the social aspects of game play that often eclipse the importance of game-mechanics knowledge. At the time of this research, playing World of Warcraft and developing expertise in the game happened roughly within a two-stage process: (1 leveling up, or advancing one's character or avatar while learning the mechanics of the game, and (2 drawing on social capital gained during the first stage to join a group of up to 40 players to partake in high-end or endgame content.

  12. Verbal aggressiveness and state anxiety of volleyball players and coaches.

    Science.gov (United States)

    Bekiari, Alexandra; Patsiaouras, Asterios; Kokaridas, Dimitrios; Sakellariou, Kimon

    2006-10-01

    The purpose of the present study was to examine the relation of verbal aggressiveness and state anxiety (somatic, cognitive, and self-confidence) in sports settings based on the ratings by volleyball coaches and their athletes. The sample consisted of volleyball athletes (n=208; 98 men and 110 women) and their coaches (n=20; 16 men and 4 women). Analysis showed that male volleyball players rated somatic anxiety higher and were more affected by the verbal aggressiveness of their coaches than female volleyball players. No mean differences were significant for male and female coaches on somatic or cognitive anxiety, self-confidence, or verbal aggressiveness. Also, correlation between subscale scores for male and female volleyball players and coaches was found. The correlations of verbal aggressiveness with self-confidence and anxiety were positive for these athletes, leading them to better behavior. This relationship needs further examination in sport settings.

  13. METRIC TESTS CHARACTERISTIC FOR ESTIMATING JUMPING FOR VOLLEYBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Toplica Stojanović

    2008-08-01

    Full Text Available With goal to establish metric tests characteristics for estimating jumping for volleyball players, it was organized a pilot research on pattern of 23 volleyball players from cadet team and 23 students from high-school. For needs of this research four tests are valid for estimation, jump in block with left and right leg and jump in spike with left and right leg. Each test has been taken three times, so that we could with test-re test method determine their reliability, and with factor analysis their validity. Data were processed by multivariate analysis (item analysis, factor analysis from statistical package „Statistica 6.0 for windows“. On the results of research and discussion we can say that the tests had high coefficient of reliability, as well as factor validity, and these tests can be used to estimate jumping for volleyball players.

  14. Modeling the Semiotic Structure of Player-Characters

    DEFF Research Database (Denmark)

    Vella, Daniel

    2014-01-01

    When game studies has tackled the player-character, it has tended to do so by means of an opposition to the notion of the avatar, with the result that the ontological and semiotic nature of the character in itself has not been given due attention. This paper draws on understandings of character...... from the fields of narratology and literary theory to highlight the double-layered ontology of character as both a possible individual and as a semiotic construction. Uri Margolin’s narratological model of character signification is used as the basis for developing a semiotic-structural model...... of the player-character that addresses its specific medialities and formal nature – a task which is performed through illustrative close examinations of the player-characters in The Last of Us (Naughty Dog 2013) and Gone Home (The Fullbright Company 2013)....

  15. Three-player conflicting interest games and nonlocality

    Science.gov (United States)

    Bolonek-Lasoń, Katarzyna

    2017-08-01

    We outline the general construction of three-player games with incomplete information which fulfil the following conditions: (i) symmetry with respect to the permutations of players; (ii) the existence of an upper bound for total payoff resulting from Bell inequalities; (iii) the existence of both fair and unfair Nash equilibria saturating this bound. Conditions (i)-(iii) imply that we are dealing with conflicting interest games. An explicit example of such a game is given. A quantum counterpart of this game is considered. It is obtained by keeping the same utilities but replacing classical advisor by a quantum one. It is shown that the quantum game possesses only fair equilibria with strictly higher payoffs than in the classical case. This implies that quantum nonlocality can be used to resolve the conflict between the players.

  16. Two-player envy-free multi-cake division

    CERN Document Server

    Cloutier, John; Su, Francis Edward

    2009-01-01

    We introduce a generalized cake-cutting problem in which we seek to divide multiple cakes so that two players may get their most-preferred piece selections: a choice of one piece from each cake, allowing for the possibility of linked preferences over the cakes. For two players, we show that disjoint envy-free piece selections may not exist for two cakes cut into two pieces each, and they may not exist for three cakes cut into three pieces each. However, there do exist such divisions for two cakes cut into three pieces each, and for three cakes cut into four pieces each. The resulting allocations of pieces to players are Pareto-optimal with respect to the division. We use a generalization of Sperner's lemma on the polytope of divisions to locate solutions to our generalized cake-cutting problem.

  17. Psychosocial Stress and Sport Injuries in Tennis Players

    Directory of Open Access Journals (Sweden)

    Amador Blas Redondo

    2011-09-01

    Full Text Available The purpose of this study was to assess the perceived social stress and its relation to sports injuries in tennis players. Sixty-three male tennis players, with a mean age of 31.62 years (SD = 8.93, Sports Clubs belonging to the Province of Alicante (Spain completed instruments of psychosocial stress and injuries sustained during the previous year the assessment. The results indicate that life events experienced was related to some of the injuries suffered by players. Relationships were found between the degree of psychological stress experienced and the negative evaluation of this strain, the type (lesions on wrists, ankles and sprains, and severity of injuries (minor injuries.

  18. Adaptations to speed endurance training in highly trained soccer players

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Fiorenza, Matteo; Lund, Anders

    2016-01-01

    PURPOSE: The present study examined whether a period of additional speed endurance training would improve intense intermittent exercise performance in highly trained soccer players during the season and whether the training changed aerobic metabolism and the level of oxidative enzymes in type I...... and II muscle fibers. METHODS: During the last nine weeks of the season, thirteen semi-professional soccer players performed additional speed endurance training sessions consisting of 2-3 sets of 8 - 10 repetitions of 30 m sprints with 10 s of passive recovery (SET). Before and after SET, subjects...... in type I and II fibers did not change. CONCLUSION: In highly trained soccer players, additional speed endurance training is associated with an improved ability to perform repeated high-intensity work. To what extent the training-induced changes in V˙O2 kinetics and mechanical efficiency in type I fibers...

  19. Biomechanics of Heading a Soccer Ball: Implications for Player Safety

    Directory of Open Access Journals (Sweden)

    Charles F. Babbs

    2001-01-01

    Full Text Available To better understand the risk and safety of heading a soccer ball, the author created a set of simple mathematical models based upon Newton�s second law of motion to describe the physics of heading. These models describe the player, the ball, the flight of the ball before impact, the motion of the head and ball during impact, and the effects of all of these upon the intensity and the duration of acceleration of the head. The calculated head accelerations were compared to those during presumably safe daily activities of jumping, dancing, and head nodding and also were related to established criteria for serious head injury from the motor vehicle crash literature. The results suggest heading is usually safe but occasionally dangerous, depending on key characteristics of both the player and the ball. Safety is greatly improved when players head the ball with greater effective body mass, which is determined by a player�s size, strength, and technique. Smaller youth players, because of their lesser body mass, are more at risk of potentially dangerous headers than are adults, even when using current youth size balls. Lower ball inflation pressure reduces risk of dangerous head accelerations. Lower pressure balls also have greater “touch” and “playability”, measured in terms of contact time and contact area between foot and ball during a kick. Focus on teaching proper technique, the re-design of age-appropriate balls for young players with reduced weight and inflation pressure, and avoidance of head contact with fast, rising balls kicked at close range can substantially reduce risk of subtle brain injury in players who head soccer balls.

  20. Head Impact Exposure and Neurologic Function of Youth Football Players.

    Science.gov (United States)

    Munce, Thayne A; Dorman, Jason C; Thompson, Paul A; Valentine, Verle D; Bergeron, Michael F

    2015-08-01

    Football players are subjected to repetitive impacts that may lead to brain injury and neurologic dysfunction. Knowledge about head impact exposure (HIE) and consequent neurologic function among youth football players is limited. This study aimed to measure and characterize HIE of youth football players throughout one season and explore associations between HIE and changes in selected clinical measures of neurologic function. Twenty-two youth football players (11-13 yr) wore helmets outfitted with a head impact telemetry (HIT) system to quantify head impact frequency, magnitude, duration, and location. Impact data were collected for each practice (27) and game (9) in a single season. Selected clinical measures of balance, oculomotor performance, reaction time, and self-reported symptoms were assessed before and after the season. The median individual head impacts per practice, per game, and throughout the entire season were 9, 12, and 252, respectively. Approximately 50% of all head impacts (6183) had a linear acceleration between 10g and 20g, but nearly 2% were greater than 80g. Overall, the head impact frequency distributions in this study population were similar in magnitude and location as in high school and collegiate football, but total impact frequency was lower. Individual changes in neurologic function were not associated with cumulative HIE. This study provides a novel examination of HIE and associations with short-term neurologic function in youth football and notably contributes to the limited HIE data currently available for this population. Whereas youth football players can experience remarkably similar head impact forces as high school players, cumulative subconcussive HIE throughout one youth football season may not be detrimental to short-term clinical measures of neurologic function.

  1. In-season training periodization of professional soccer players

    Directory of Open Access Journals (Sweden)

    A Los Arcos

    2017-04-01

    Full Text Available The aim of this study was to quantify the seasonal perceived respiratory and muscular training loads (i.e., sRPEres-TL and sRPEmus-TL completed by elite-oriented young professional soccer players. Twentyfour players (20.3 ± 2.0 years belonging to the same reserve team of a Spanish La Liga club participated in this study. Only the players that were available to train for a whole week with the team and also to play the weekly game were considered: Starters, players that participated in the match for at least 45 min and Non- Starters, players that did not participate or played less than 45 minutes in the match. The competitive period was analysed after the division into 5x6-8 week blocks and 35x1 week microcycles. Data were also analysed with respect to number of days before the immediate match. Weekly TL variation across the in-season blocks was trivial-small for both groups except between Block 2 and Block 3 (ES= moderate. Substantial TL differences (ES= small–very likely were found between training days, the TL pattern being a progressive increase up to MD-3 followed by a decrease until MD-1. Except for the match, sRPEres-/sRPEmus-TL was very similar between Starters and Non-Starters. In summary, perceived TL across the season displayed limited variation. Coaches periodized training contents to attain the highest weekly TL 72 hours before the match to progressively unload the players between MD-3 and the match day. The data revealed that the TL arising from the weekly game was solely responsible for the observed higher weekly TL of Starters in comparison with Non-Starters.

  2. Comparison of two aerobic field tests in young tennis players.

    Science.gov (United States)

    Fargeas-Gluck, Marie-Agnès; Léger, Luc A

    2012-11-01

    This study compares the maximal responses of a new aerobic tennis field test, the NAVTEN to a known aerobic field test, often used with young tennis players, that is, the continuous multistage 20-m shuttle run test (20-m SRT). The NAVTEN is an intermittent (1-minute/1-minute) multistage test with side-to-side displacements and ball hitting. Ten young elite tennis players aged 12.9 ± 0.3 (mean ± SD) randomly performed both tests and were continuously monitored for heart rate (HR) and oxygen uptake (V[Combining Dot Above]O2) using the Vmax ST (Sensormedics). The 20-m SRT and NAVTEN show similar HRpeak (202 ± 6.1 vs. 208 ± 9.5, respectively) and V[Combining Dot Above]O2peak (54.2 ± 5.9 vs. 54.9 ± 6.0 ml·kg·min). Pearson correlations between both tests were 0.88 and 0.92 for V[Combining Dot Above]O2peak and maximal speed, respectively. The NAVTEN yielded V[Combining Dot Above]O2peak values that are typical for active subjects of that age and are similar to the 20-m SRT supporting its use to measure aerobic fitness of young tennis players in specific and entertaining field conditions. The fact that two-thirds of the tennis players achieved a different ranking (±1 rank) with the NAVTEN and the 20-m SRT suggests that the NAVTEN may be more specific than the 20-m SRT to assess aerobic fitness of tennis players. From a practical point of view, the NAVTEN test is more specific and pedagogical for young tennis players even though both tests yield similar maximal values.

  3. Influence of fatigue on tackling technique in rugby league players.

    Science.gov (United States)

    Gabbett, Tim J

    2008-03-01

    This study investigated the influence of fatigue on tackling technique in rugby league players and determined the relationship between selected physiological capacities and fatigue-induced decrements in tackling technique. Eight rugby league players underwent a standardized one-on-one tackling drill in a 10-m grid. Players performed the one-on-one tackling drill before strenuous exercise and following game-specific repeated-effort exercise of progressively increasing intensities (corresponding to moderate, heavy, and very heavy intensity) in order to induce fatigue that was representative of match conditions. Video footage was taken from the rear, side, and front of the defending player. Tackling technique was objectively assessed using standardized technical criteria. In addition, all players underwent measurements of standard anthropometry (height, body mass, and sum of 7 skinfold measurements), speed (10-, 20-, and 40-m sprint), muscular power (vertical jump), agility (L run), and estimated maximal aerobic power (VO2max multistage fitness test). A progressive increase in total repeated-effort time, heart rate, blood lactate concentration, and ratings of perceived exertion occurred throughout the repeated-effort protocol, demonstrating a progressive increase in intensity and fatigue. Fatigue resulted in progressive reductions in tackling technique. Players with the best tackling technique in a nonfatigued state demonstrated the greatest decrement in tackling technique under fatigued conditions. In addition, a significant association was observed between estimated VO2max (r = -0.62) and agility (r = 0.68) and fatigue-induced decrements in tackling technique. From a practical perspective, these findings suggest that strength and conditioning programs designed to develop endurance, change of direction speed, and anticipation skills may reduce fatigue-induced decrements in tackling technique. Furthermore, any defensive drills designed to improve tackling technique

  4. Computing Sequential Equilibria for Two-Player Games

    DEFF Research Database (Denmark)

    Miltersen, Peter Bro; Sørensen, Troels Bjerre

    2006-01-01

    Koller, Megiddo and von Stengel showed how to efficiently compute minimax strategies for two-player extensive-form zero-sum games with imperfect information but perfect recall using linear programming and avoiding conversion to normal form. Koller and Pfeffer pointed out that the strategies...... a sequential equilibrium are computed. In particular, we show that a sequential equilibrium for a two-player zero-sum game with imperfect information but perfect recall can be found in polynomial time. In addition, the equilibrium we find is normal-form perfect. Our technique generalizes to general-sum games...

  5. The expected-outcome model of two-player games

    CERN Document Server

    Abramson, Bruce

    1990-01-01

    The Expected-Outcome Model of Two-Player Games deals with the expected-outcome model of two-player games, in which the relative merit of game-tree nodes, rather than board positions, is considered. The ambiguity of static evaluation and the problems it generates in the search system are examined and the development of a domain-independent static evaluator is described. Comprised of eight chapters, this book begins with an overview of the rationale for the mathematical study of games, followed by a discussion on some previous artificial intelligence (AI) research efforts on game-trees. The nex

  6. Radiographic knee osteoarthritis in ex-elite table tennis players

    Directory of Open Access Journals (Sweden)

    Rajabi Reza

    2012-02-01

    Full Text Available Abstract Background Table tennis involves adoption of the semi-flexed knee and asymmetrical torsional trunk movements creating rotational torques on the knee joint which may predispose players to osteoarthritis (OA of the knee. This study aims to compare radiographic signs of knee OA and associated functional levels in ex-elite male table tennis players and control subjects. Methods Study participants were 22 ex-elite male table tennis players (mean age 56.64 ± 5.17 years with 10 years of involvement at the professional level and 22 non-athletic males (mean age 55.63 ± 4.08 years recruited from the general population. A set of three radiographs taken from each knee were evaluated by an experienced radiologist using the Kellgren and Lawrence (KL scale (0-4 to determine radiographic levels of OA severity. The intercondylar distance was taken as a measure of lower limb angulation. Participants also completed the pain, stiffness, and physical function categories of the Western Ontario and McMaster University Osteoarthritis Index (WOMAC 3.1 questionnaire. Results The results showed 78.3% of the ex-elite table tennis players and 36.3% of controls had varying signs of radiographic knee OA with a significant difference in the prevalence levels of definite radiographic OA (KL scale > 2 found between the two groups (P ≤ 0.001. Based on the WOMAC scores, 68.2% of the ex-elite table tennis players reported symptoms of knee pain compared with 27.3% of the controls (p = 0.02 though no significant differences were identified in the mean physical function or stiffness scores between the two groups. In terms of knee alignment, 73.7% of the ex-elite athletes and 32% of the control group had signs of altered lower limb alignment (genu varum (p = 0.01. Statistical differences were found in subjects categorized as having radiographic signs of OA and altered lower limb alignment (p = 0.03. Conclusions Ex-elite table tennis players were found to have increased

  7. Nearly All Autopsied NFL Players Show Trauma-Linked Brain Disease

    Science.gov (United States)

    ... gov/news/fullstory_167405.html Nearly All Autopsied NFL Players Show Trauma-Linked Brain Disease No position ... 2017 (HealthDay News) -- Ninety-nine percent of former NFL players who donated their brain to science turned ...

  8. First Days of Preseason Practice Pose Big Heat Risks for College Football Players

    Science.gov (United States)

    ... Preseason Practice Pose Big Heat Risks for College Football Players Coaches, trainers need to be aware of ... FRIDAY, Aug. 26, 2016 (HealthDay News) -- As college football players trade in their beach towels for helmets ...

  9. Postural stability decreases in elite young soccer players after a competitive soccer match

    DEFF Research Database (Denmark)

    Brito, João; Fontes, Ivo; Ribeiro, Fernando

    2012-01-01

    To investigate the effects of an official soccer match on postural stability in youth elite soccer players.......To investigate the effects of an official soccer match on postural stability in youth elite soccer players....

  10. Factors associated with deep tissue injury in male wheelchair basketball players of a Japanese national team

    Directory of Open Access Journals (Sweden)

    Hirotaka Mutsuzaki

    2014-04-01

    Full Text Available Maintenance of the sporting activity of elite athletes in adapted sports can be difficult if a secondary disorder, such as a pressure ulcer, occurs. Pressure ulcers result from deep tissue injuries by external pressure. The purpose of this study was to use ultrasonography to investigate deep tissue injuries in male wheelchair basketball players of a Japanese national team, and to determine factors associated with the injuries (e.g., body mass index, class of wheelchair basketball, underlying disease, length of athletic career, and whether use of wheelchair is primarily for playing basketball. Twenty male Japanese wheelchair basketball players on the national team for the 2012 London Paralympic Games (12 representative players and eight candidate representative players participated in this study. The sacral region and bilateral ischial regions in each athlete were examined by ultrasonography to detect low-echoic lesions indicative of deep tissue injuries. Nine (45% players had low-echoic lesions, which were detected in 10 of 60 areas. Eight lesions were detected in the sacral region and two lesions were detected in the ischial region. More players with spinal cord injury had low-echoic lesions [9 (69.2% of 13 players], compared to players with skeletal system disease [0 (0% of 7 players, p = 0.002]. Players who used a wheelchair in daily life were more likely to have low-echoic lesions [8 (66.74% of 12 players], compared to players who primarily used a wheelchair for playing basketball [1 (12.5% of 8 players, p = 0.010]. Deep tissue injuries were detected in 45% of male Japanese wheelchair basketball players on the national team. Players with spinal cord injury and players who used a wheelchair in daily life were more likely to have deep tissue injuries, particularly in the sacral region. The lesions were small, but a periodic medical check should be performed to maintain athletes' sporting life.

  11. Physical Characteristics and Performance of Japanese Top-Level American Football Players.

    Science.gov (United States)

    Yamashita, Daichi; Asakura, Masaki; Ito, Yoshihiko; Yamada, Shinzo; Yamada, Yosuke

    2017-09-01

    Yamashita, D, Asakura, M, Ito, Y, Yamada, S, and Yamada, Y. Physical characteristics and performance of Japanese top-level American football players. J Strength Cond Res 31(9): 2455-2461, 2017-This study aimed to compare the physical characteristics and performance between top-level nonprofessional football players in Japan and National Football League (NFL) Combine invited players and between top-level and middle-level players in Japan to determine the factors that enhance performance in international and national competitions. A total of 168 American football players (>20 years) in Japan participated in an anthropometric (height and weight) and physical (vertical jump, long jump, 40-yard dash, pro-agility shuttle, 3-cone drill, and bench press repetition test) measurement program based on the NFL Combine program to compete in the selection of candidates for the Senior World Championship. All players were categorized into 1 of the 3 position groups based on playing position: skill players, big skill players, and linemen. Japanese players were additionally categorized into selected and nonselected players for the second tryout. The NFL Combine candidates had significantly better performance than selected Japanese players on all variables except on performance related to quickness among the 3 position groups. Compared with nonselected players, selected Japanese skill players had better performance in the 40-yard dash and bench press test and big skill players had better performance in the vertical jump, broad jump, and 40-yard dash. Selected and nonselected Japanese linemen were not different in any measurements. These results showed the challenges in American football in Japan, which include not only improving physical performance of top-level players, but also increasing the number of football players with good physical performance.

  12. Physical Characteristics and Performance of Japanese Top-Level American Football Players

    Science.gov (United States)

    Asakura, Masaki; Ito, Yoshihiko; Yamada, Shinzo; Yamada, Yosuke

    2017-01-01

    Abstract Yamashita, D, Asakura, M, Ito, Y, Yamada, S, and Yamada, Y. Physical characteristics and performance of Japanese top-level American football players. J Strength Cond Res 31(9): 2455–2461, 2017—This study aimed to compare the physical characteristics and performance between top-level nonprofessional football players in Japan and National Football League (NFL) Combine invited players and between top-level and middle-level players in Japan to determine the factors that enhance performance in international and national competitions. A total of 168 American football players (>20 years) in Japan participated in an anthropometric (height and weight) and physical (vertical jump, long jump, 40-yard dash, pro-agility shuttle, 3-cone drill, and bench press repetition test) measurement program based on the NFL Combine program to compete in the selection of candidates for the Senior World Championship. All players were categorized into 1 of the 3 position groups based on playing position: skill players, big skill players, and linemen. Japanese players were additionally categorized into selected and nonselected players for the second tryout. The NFL Combine candidates had significantly better performance than selected Japanese players on all variables except on performance related to quickness among the 3 position groups. Compared with nonselected players, selected Japanese skill players had better performance in the 40-yard dash and bench press test and big skill players had better performance in the vertical jump, broad jump, and 40-yard dash. Selected and nonselected Japanese linemen were not different in any measurements. These results showed the challenges in American football in Japan, which include not only improving physical performance of top-level players, but also increasing the number of football players with good physical performance. PMID:28052052

  13. EcoTRADE - a multi player network game of a tradable permit market for biodiversity credits

    CERN Document Server

    Hartig, Florian; Drechsler, Martin

    2008-01-01

    EcoTRADE is a multi player network game of a virtual biodiversity credit market. Each player controls the land use of a certain amount of parcels on a virtual landscape. The biodiversity credits of a particular parcel depend on neighboring parcels, which may be owned by other players. The game can be used to study the strategies of players in experiments or classroom games and also as a communication tool for stakeholders participating in credit markets that include spatially interdependent credits.

  14. Comparison of Speed, Agility, Anaerobic Strength and Anthropometric Characteristics in Male Football and Futsal Players

    Science.gov (United States)

    Kartal, Resat

    2016-01-01

    The purpose of this study is to compare speed, agility, anaerobic strength and some anthropometric characteristics in male football and futsal players. The sample of the study is composed of male futsal team players of Aydin Adnan Menderes University (19-24 aged) (n = 12) and Aydin Merkez Yeniköy Football Club players (19-24 aged) (n = 12). Within…

  15. High School Football Players and Their Coaches: A Qualitative Study of Their Relationships

    Science.gov (United States)

    Skaza, Robert J.

    2014-01-01

    This basic qualitative study of high school football coach-player relationships explores the players' perceptions of these relationships, specifically the perceptions the players have of how these relationships influenced their lives. This study allowed the researcher to examine the characteristics of high school football coaches as they relate to…

  16. Physical qualities and activity profiles of sub-elite and recreational Australian football players.

    Science.gov (United States)

    Stein, Josh G; Gabbett, Tim J; Townshend, Andrew D; Dawson, Brian T

    2015-11-01

    To investigate the relationship between physical qualities and match activity profiles of recreational Australian football players. Prospective cohort study. Forty players from three recreational Australian football teams (Division One, Two and Three) underwent a battery of fitness tests (vertical jump, 10 and 40 m sprint, 6 m × 30 m repeated sprint test, Yo-Yo intermittent recovery level Two and 2-km time trial). The activity profiles of competitive match-play were quantified using 10-Hz Global Positioning System units. Division One players possessed greater maximum velocity, Yo-Yo level Two and 2-km time trial performances than Division Two and Three players. In addition, Division One players covered greater relative distance, and relative distances at moderate- and high-intensities during match-play than Division Two and Three players. Division Two players had better 2-km time trial performances than Division Three players. Positive associations (P football players competing at a higher level exhibit greater physical qualities and match-play activity profiles than lesser-skilled recreational players. Acceleration and maximum velocity, 2-km time trial and Yo-Yo level Two performances discriminate between players of different playing levels, and are related to physical match performance in recreational Australian football. The development of these qualities is likely to contribute to improved match performance in recreational Australian football players. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  17. Self-Esteem Profile among the Female Futsal-Football Players at Jordanian Clubs

    Science.gov (United States)

    Khasawneh, Aman

    2015-01-01

    This study aimed at identifying the level of physical and body self-esteem among the female futsal - football players at Jordanian clubs. The sample of the study was composed of (38) female players among the Jordanian clubs' players of futsal-football who were chosen randomly out of the study community, and the self-esteem scale was used,…

  18. High School Football Players and Their Coaches: A Qualitative Study of Their Relationships

    Science.gov (United States)

    Skaza, Robert J.

    2014-01-01

    This basic qualitative study of high school football coach-player relationships explores the players' perceptions of these relationships, specifically the perceptions the players have of how these relationships influenced their lives. This study allowed the researcher to examine the characteristics of high school football coaches as they relate to…

  19. Design and Usability Testing of an Audio Platform Game for Players with Visual Impairments

    Science.gov (United States)

    Oren, Michael; Harding, Chris; Bonebright, Terri L.

    2008-01-01

    This article reports on the evaluation of a novel audio platform game that creates a spatial, interactive experience via audio cues. A pilot study with players with visual impairments, and usability testing comparing the visual and audio game versions using both sighted players and players with visual impairments, revealed that all the…

  20. Training habits and injuries of masters' level football players: a preliminary report.

    Science.gov (United States)

    Newsham-West, R; Button, C; Milburn, P D; Mündermann, A; Sole, G; Schneiders, A G; Sullivan, S J

    2009-05-01

    To profile training habits and injuries in football players participating in a national Masters tournament. A cross-sectional retrospective study design was used to survey male football players attending the 2008 New Zealand Masters Games. Information regarding player demographics, football injuries, football related training, and risk factors for injury were collected. 199 Players were recruited, with a median age of 44 yrs (range 35-73) and a median football playing history of 15 yrs (range 0-66). Irrespective of age, 112 (84%) players included a warm-up and 104 (78%) included a stretching regime in their regular training programme. In the 12 months prior to the tournament, 128 football related injuries were reported by 93 players (64 injuries/100 players or 46 injured players/100 players). The most frequently injured region was the lower limb; specifically the lower leg (n=23), ankle (n=18), hamstring (n=17), knee (n=15), and Achilles tendon (n=15). This study provides a preliminary insight into the training habits and injury profiles of Masters football players. Despite all players including some form of injury prevention strategy in their training, a significant number of players experienced an injury in the 12 months prior to the tournament.

  1. DMPD: TLR3 in antiviral immunity: key player or bystander? [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16027039 TLR3 in antiviral immunity: key player or bystander? Schroder M, Bowie AG.... Trends Immunol. 2005 Sep;26(9):462-8. (.png) (.svg) (.html) (.csml) Show TLR3 in antiviral immunity: key pl...ayer or bystander? PubmedID 16027039 Title TLR3 in antiviral immunity: key player or bystander? Authors Schr

  2. Modeling Longitudinal Changes in 5m Sprinting Performance Among Young Male Tennis Players

    NARCIS (Netherlands)

    Kramer, Tamara; Valente-Dos-Santos, Joao; Coelho-E-Silva, Manuel J.; Malina, Robert M.; Huijgen, Barbara C. H.; Smith, Joanne; Elferink-Gemser, Marije T.; Visscher, Chris

    2016-01-01

    Year-to-year changes in sprinting in youth tennis players were examined in a mixed-longitudinal study (256 male players, aged 10-15 years: 993 measurements). Height (h), body mass (BM), lower limb explosive strength (LLES), and a 5-m sprint were measured over five years. During that period, players

  3. The Ability of Elite Table Tennis Players with Intellectual Disabilities to Adapt Their Service/Return

    Science.gov (United States)

    Van Biesen, Debbie; Verellen, Joeri; Meyer, Christophe; Mactavish, Jennifer; Van de Vliet, Peter; Vanlandewijck, Yves

    2010-01-01

    In this study the ability of elite table tennis players with intellectual disability (ID) to adapt their service/return to specific ball spin characteristics was investigated. This was done by examining the performance of 39 players with ID and a reference group of 8 players without ID on a standardized table tennis specific test battery. The…

  4. Achievement Goals, Motivational Climate and Sportspersonship: A Study of Young Handball Players

    Science.gov (United States)

    Stornes, Tor; Ommundsen, Yngvar

    2004-01-01

    The aim of this study was to investigate the relationships between achievement goals, perceptions of motivational climate and sportspersonship in a sample of young male Norwegian handball players. A cross-sectional study of 440 male handball players aged from 14 to 16 was conducted, in which the players responded to a questionnaire measuring…

  5. Effect of Core Training on 16 Year-Old Soccer Players

    Science.gov (United States)

    Afyon, Yakup Akif

    2014-01-01

    Core trainings have been widely used by trainers recently in order to improve performance of soccer players. In this context, the aim of this study is to examine the effect of core training on some motoric capabilities of 16 years old soccer players. Thirty certified soccer players who were 16 years old from B.B. Bodrumspor Club in 2013-2014…

  6. Pressure at play: measuring player approach and avoidance through the keyboard

    NARCIS (Netherlands)

    Hoogen, Wouter van den; Braad, Eelco; IJsselsteijn, Wijnand

    2014-01-01

    With the increased adoption of real-time objective measurements of player experience, advances have been made in characterising the dynamically changing aspects of the player experience during gameplay itself. A direct coupling to player action, however, is not without challenges. Many physiological

  7. Pressure at play: measuring player approach and avoidance behaviour through the keyboard

    NARCIS (Netherlands)

    Hoogen, Wouter M. van den; Braad, Eelco P.; IJsselsteijn, Wijnand A.

    2014-01-01

    With the increased adoption of real-time objective measurements of player experience, advances have been made in characterising the dynamically changing aspects of the player experience during gameplay itself. A direct coupling to player action, however, is not without challenges. Many physiological

  8. Forecasting the Market for New Communication Technology: The Home Video Player Experience.

    Science.gov (United States)

    Klopfenstein, Bruce C.

    This paper describes a critical study of the available forecasts and forecasting studies for the home video player market over a 15-year period which was undertaken to discover why so many forecasts were wrong about consumer adoption of home videocassette players and videodisk players, the reasons for these errors, and ways in which this knowledge…

  9. Online and live regular poker players: Do they differ in impulsive sensation seeking and gambling practice?

    Science.gov (United States)

    Barrault, Servane; Varescon, Isabelle

    2016-03-01

    Background and aims Online gambling appears to have special features, such as anonymity, speed of play and permanent availability, which may contribute to the facilitation and increase in gambling practice, potentially leading to problem gambling. The aims of this study were to assess sociodemographic characteristics, gambling practice and impulsive sensation seeking among a population of regular poker players with different levels of gambling intensity and to compare online and live players. Methods 245 regular poker players (180 online players and 65 live players) completed online self-report scales assessing sociodemographic data, pathological gambling (SOGS), gambling practice (poker questionnaire) and impulsive sensation seeking (ImpSS). We used SOGS scores to rank players according to the intensity of their gambling practice (non-pathological gamblers, problem gamblers and pathological gamblers). Results All poker players displayed a particular sociodemographic profile: they were more likely to be young men, executives or students, mostly single and working full-time. Online players played significantly more often whereas live players reported significantly longer gambling sessions. Sensation seeking was high across all groups, whereas impulsivity significantly distinguished players according to the intensity of gambling. Discussion Our results show the specific profile of poker players. Both impulsivity and sensation seeking seem to be involved in pathological gambling, but playing different roles. Sensation seeking may determine interest in poker whereas impulsivity may be involved in pathological gambling development and maintenance. Conclusions This study opens up new research perspectives and insights into preventive and treatment actions for pathological poker players.

  10. Deterministic Quantum Key Distribution Using Gaussian-Modulated Squeezed States

    Institute of Scientific and Technical Information of China (English)

    何广强; 朱俊; 曾贵华

    2011-01-01

    A continuous variable ping-pong scheme, which is utilized to generate deterministic private key, is proposed. The proposed scheme is implemented physically by using Ganssian-modulated squeezed states. The deterministic char- acteristic, i.e., no basis reconciliation between two parties, leads a nearly two-time efficiency comparing to the standard quantum key distribution schemes. Especially, the separate control mode does not need in the proposed scheme so that it is simpler and more available than previous ping-pong schemes. The attacker may be detected easily through the fidelity of the transmitted signal, and may not be successful in the beam splitter attack strategy.

  11. 一种改进的量子“乒乓”协议安全检测策略及其安全性分析(英文)

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In order to transmit the secure messages,a deterministic secure quantum direct communication protocol,called the "Ping-pong"protocol was proposed by Bostrm and Felbinger [Phys.Rev.Lett.89,187902(2002) ].But the protocol was proved to have many vulnerabilities,and can be attacked by eavesdroppers.To overcome the problem,an improved security detection strategy which inserts the | 0〉,| 1〉,|+〉and |-〉particles into the messages as the decoy particles randomly in the"Ping-pong"protocol is presented.During the se...

  12. Octonionization of three player, two strategy maximally entangled quantum games

    OpenAIRE

    Ahmed, Aden; Bleiler, Steve; Khan, Faisal Shah

    2008-01-01

    We develop an octonionic representation of the payoff function for three player, two strategy, maximally entangled quantum games in order to obtain computationally friendly version of this function. This computational capability is then exploited to analyze and potentially classify the Nash equilibria in the quantum games.

  13. Reciprocity on the hardwood: passing patterns among professional basketball players.

    Science.gov (United States)

    Willer, Robb; Sharkey, Amanda; Frey, Seth

    2012-01-01

    Past theory and research view reciprocal resource sharing as a fundamental building block of human societies. Most studies of reciprocity dynamics have focused on trading among individuals in laboratory settings. But if motivations to engage in these patterns of resource sharing are powerful, then we should observe forms of reciprocity even in highly structured group environments in which reciprocity does not clearly serve individual or group interests. To this end, we investigated whether patterns of reciprocity might emerge among teammates in professional basketball games. Using data from logs of National Basketball Association (NBA) games of the 2008-9 season, we estimated a series of conditional logistic regression models to test the impact of different factors on the probability that a given player would assist another player in scoring a basket. Our analysis found evidence for a direct reciprocity effect in which players who had "received" assists in the past tended to subsequently reciprocate their benefactors. Further, this tendency was time-dependent, with the probability of repayment highest soon after receiving an assist and declining as game time passed. We found no evidence for generalized reciprocity - a tendency to "pay forward" assists - and only very limited evidence for indirect reciprocity - a tendency to reward players who had sent others many assists. These findings highlight the power of reciprocity to shape human behavior, even in a setting characterized by extensive planning, division of labor, quick decision-making, and a focus on inter-group competition.

  14. Reciprocity on the hardwood: passing patterns among professional basketball players.

    Directory of Open Access Journals (Sweden)

    Robb Willer

    Full Text Available Past theory and research view reciprocal resource sharing as a fundamental building block of human societies. Most studies of reciprocity dynamics have focused on trading among individuals in laboratory settings. But if motivations to engage in these patterns of resource sharing are powerful, then we should observe forms of reciprocity even in highly structured group environments in which reciprocity does not clearly serve individual or group interests. To this end, we investigated whether patterns of reciprocity might emerge among teammates in professional basketball games. Using data from logs of National Basketball Association (NBA games of the 2008-9 season, we estimated a series of conditional logistic regression models to test the impact of different factors on the probability that a given player would assist another player in scoring a basket. Our analysis found evidence for a direct reciprocity effect in which players who had "received" assists in the past tended to subsequently reciprocate their benefactors. Further, this tendency was time-dependent, with the probability of repayment highest soon after receiving an assist and declining as game time passed. We found no evidence for generalized reciprocity - a tendency to "pay forward" assists - and only very limited evidence for indirect reciprocity - a tendency to reward players who had sent others many assists. These findings highlight the power of reciprocity to shape human behavior, even in a setting characterized by extensive planning, division of labor, quick decision-making, and a focus on inter-group competition.

  15. Concussion Education for High School Football Players: A Pilot Study

    Science.gov (United States)

    Manasse-Cohick, Nancy J.; Shapley, Kathy L.

    2014-01-01

    This survey study compared high school football players' knowledge and attitudes about concussion before and after receiving concussion education. There were no significant changes in the Concussion Attitude Index. Results revealed a statistically significant difference in the athletes' scores for the Concussion Knowledge Index,…

  16. LIPOSARCOMA OF THE KNEE IN A TENNIS PLAYER: CASE REPORT

    Science.gov (United States)

    Filho, Jorge Sayum; Sayum, Jorge; de Carvalho, Rogério Teixeira; Garms, Emerson; Ramos, Leonardo Addeo; Matsuda, Marcelo Mitsura; Ejnisman, Benno; Cohen, Moisés

    2015-01-01

    Liposarcoma is an uncommon malignant tumor. It originates in the mesenchymal cells, and is the most common of the soft tissue sarcomas. The authors report a case of a 40 year-old male tennis player with liposarcoma in the posterior right knee and distal thigh region. PMID:27047841

  17. Enhancing Performance & Preventing Injuries in Team Sport Players

    NARCIS (Netherlands)

    van der Does, Hendrike

    2016-01-01

    Next to physical load and recovery as a result of training, psychosocial stress and recovery affect performance and injury risk of team sport players. This can be concluded based on a series of studies that focus on the relation between jumping technique, training load, training recovery, psychosoci

  18. Adolescents risky MP3-player listening and its psychosocial correlates

    NARCIS (Netherlands)

    Vogel, Ineke; Brug, Johannes; van der Ploeg, Catharina P. B.; Raat, Hein

    2011-01-01

    Analogue to occupational noise-induced hearing loss, MP3-induced hearing loss may be evolving into a significant social and public health problem. To inform prevention strategies and interventions, this study investigated correlates of adolescents' risky MP3-player listening behavior primarily infor

  19. Active Player Modeling in the Iterated Prisoner's Dilemma.

    Science.gov (United States)

    Park, Hyunsoo; Kim, Kyung-Joong

    2016-01-01

    The iterated prisoner's dilemma (IPD) is well known within the domain of game theory. Although it is relatively simple, it can also elucidate important problems related to cooperation and trust. Generally, players can predict their opponents' actions when they are able to build a precise model of their behavior based on their game playing experience. However, it is difficult to make such predictions based on a limited number of games. The creation of a precise model requires the use of not only an appropriate learning algorithm and framework but also a good dataset. Active learning approaches have recently been introduced to machine learning communities. The approach can usually produce informative datasets with relatively little effort. Therefore, we have proposed an active modeling technique to predict the behavior of IPD players. The proposed method can model the opponent player's behavior while taking advantage of interactive game environments. This experiment used twelve representative types of players as opponents, and an observer used an active modeling algorithm to model these opponents. This observer actively collected data and modeled the opponent's behavior online. Most of our data showed that the observer was able to build, through direct actions, a more accurate model of an opponent's behavior than when the data were collected through random actions.

  20. Generic Physiological Features as Predictors of Player Experience

    DEFF Research Database (Denmark)

    Martínez, Héctor Pérez; Garbarino, Maurizio; Yannakakis, Georgios N.

    2011-01-01

    This paper examines the generality of features extracted from heart rate (HR) and skin conductance (SC) signals as predictors of self-reported player affect expressed as pairwise preferences. Artificial neural networks are trained to accurately map physiological features to expressed affect in two...

  1. Concussion Education for High School Football Players: A Pilot Study

    Science.gov (United States)

    Manasse-Cohick, Nancy J.; Shapley, Kathy L.

    2014-01-01

    This survey study compared high school football players' knowledge and attitudes about concussion before and after receiving concussion education. There were no significant changes in the Concussion Attitude Index. Results revealed a statistically significant difference in the athletes' scores for the Concussion Knowledge Index, "t"(244)…

  2. Somatotype of Competitive Youth Soccer Players From Brazil

    Directory of Open Access Journals (Sweden)

    Fidelix Yara Lucy

    2014-10-01

    Full Text Available The aim of this study was to identify the morphological configuration of youth athletes from professional soccer clubs and to verify their differences according to the tactical position on the field. Overall, 67 male players aged 15 to 17 years were evaluated. The examined anthropometric measurements included body mass, body height, skinfolds (triceps, subscapular, supraspinal and medial calf, girths (flexed and tensed arm and calf and breadths (humerus and femur. For statistical purposes, analysis of variance and post hoc Bonferroni and Kruskal-Wallis tests were used. We concluded that goalkeepers were heavier and taller than center backs (p = 0.015 and p = 0.001, midfielders (p = 0.005 and p <0.001 and center forward players (p = 0.024 and p <0.001. The average somatotype for defense, forward and goalkeeper positions was a balanced mesomorph. Midfield players showed ectomorphic-mesomorph characteristics. It was concluded that goalkeepers were characterized as being taller and heavier and that somatotype features of athletes were similar between positions, except for midfield players

  3. Monitoring load, recovery and performance in young elite soccer players

    NARCIS (Netherlands)

    Brink, Michel S.; Nederhof, Esther; Visscher, Chris; Schmikli, Sandor L.; Lemmink, Koen A. P. M.

    2010-01-01

    Brink, MS, Nederhof, E, Visscher, C, Schmikli, SL, and Lemmink, KAPM. Monitoring load, recovery, and performance in young elite soccer players. J Strength Cond Res 24(3): 597603, 2010-The purpose of this study was to investigate the relation between training load, recovery, and monthly field test pe

  4. The Development of Attention Skills in Action Video Game Players

    Science.gov (United States)

    Dye, M. W. G.; Green, C. S.; Bavelier, D.

    2009-01-01

    Previous research suggests that action video game play improves attentional resources, allowing gamers to better allocate their attention across both space and time. In order to further characterize the plastic changes resulting from playing these video games, we administered the Attentional Network Test (ANT) to action game players and…

  5. Body composition and nutritional profile of male adolescent tennis players.

    Science.gov (United States)

    Juzwiak, Claudia R; Amancio, Olga M S; Vitalle, Maria S S; Pinheiro, Marcelo M; Szejnfeld, Vera L

    2008-09-01

    In this cross-sectional study, we evaluated the body composition and dietary intake of 44 adolescent tennis players. After being divided into two groups (age 10-13 years and age 14-18), the players had their weight, height, and sexual maturation assessed. Dual-energy X-ray absorptiometry was used to assess body composition. Food intake was obtained from a non-consecutive 4-day food record. The data were analysed using the Virtual Nutri v.1.0 software and compared with the present recommendations for adolescent athletes or dietary reference intakes. Body mass index and body fat for tennis practice were adequate for 89% and 71% of the tennis players respectively, regardless of age group. A calorie deficit greater than 10% of energy expenditure was observed in 32% of the sample. Fifty percent of the athletes consumed carbohydrates in accordance with recommended values. Protein and lipid intakes were above recommended values, while fibre, calcium, potassium, magnesium, and folic acid intakes were below recommendation for 98%, 80%, 100%, 100%, and 98% of the tennis players respectively. The observed nutritional deficiencies represent an additional barrier for adolescents engaged in competitive sports to achieve an optimum nutrition to maintain growth, health, and performance.

  6. Division IAA Football Players and Risk Factors for Metabolic Syndrome

    Science.gov (United States)

    Repovich, Wendy E. S.; Babcock, Garth J.

    2012-01-01

    The purpose of this study was to determine if body composition and blood pressure (BP), two markers for Metabolic Syndrome (MetS), were correlated in college football players. Height, weight, BMI, systolic (SBP) and Diastolic (DBP) blood pressure and body composition (three measures) were assessed in a Division IAA football team (N = 55). Data…

  7. Concussion Education for High School Football Players: A Pilot Study

    Science.gov (United States)

    Manasse-Cohick, Nancy J.; Shapley, Kathy L.

    2014-01-01

    This survey study compared high school football players' knowledge and attitudes about concussion before and after receiving concussion education. There were no significant changes in the Concussion Attitude Index. Results revealed a statistically significant difference in the athletes' scores for the Concussion Knowledge Index, "t"(244)…

  8. Development of Repeated Sprint Ability in Talented Youth Basketball Players

    NARCIS (Netherlands)

    te Wierike, Sanne C. M.; de Jong, Mark C.; Tromp, Eveline J. Y.; Vuijk, Pieter J.; Lemmink, Koen A. P. M.; Malina, Robert M.; Elferink-Gemser, Marije T.; Visscher, Chris

    te Wierike, SCM, de Jong, MC, Tromp, EJY, Vuijk, PJ, Lemmink, KAPM, Malina, RM, Elferink-Gemser, MT, and Visscher, C. Development of repeated sprint ability in talented youth basketball players. J Strength Cond Res 28(4): 928-934, 2014-Factors affecting repeated sprint ability (RSA) were evaluated

  9. Not all players are equally motivated: The role of narcissism.

    Science.gov (United States)

    Roberts, Ross; Woodman, Tim; Lofthouse, Sian; Williams, Lucy

    2015-01-01

    Research on motivational climates consistently demonstrates that mastery-focused climates are associated with positive outcomes and ego-involving performance climates lead to maladaptive outcomes. However, the role of personality within such a framework has been largely ignored. To redress this imbalance, we examined the potential role of narcissism in moderating the effects of different motivational climates on leader-inspired extra effort in training. Training is where rugby players spend most of their rugby time and we were keen to examine the combination of personality and climate that might maximise the yield of such training environments. Female rugby players (n = 126) from 15 clubs completed measures of narcissism, motivational climate and effort. Moderated regression analyses revealed that narcissism moderated the relationship between motivational climate and effort. Increases in either performance or mastery climates were associated with increases in effort for narcissists; no such relationship was revealed for low narcissists. The findings demonstrate the importance of considering personality within rugby training environments, as it is clear that not every player will respond the same way to specific training conditions. Coaches who understand this and are able to tailor individualised motivational climates will likely gain the greatest benefits from their different players.

  10. Personality and Injury Risk Among ‎Professional Hockey Players

    Directory of Open Access Journals (Sweden)

    David C. Schwebel

    2009-07-01

    Full Text Available Background: Although much is known about risk for athletic injury, research on the roles of individual differences in personality and temperament on athletic injury has lagged. We hypothesized that professional athletes with high sensation-seeking and extraversion scores, and with low effortful control scores, would experience more injuries over the course of a season, would have more severe injuries, and would miss more total days of play. Methods: Prospective design with questionnaire report at time one and injury tracking throughout an 18-week athletic season. Setting: Professional hockey team in the United States. Participants: Eighteen professional hockey players (ages 21-33. Measurements: Players completed self-report personality (Sensation-Seeking Scale, Form V and temperament (the Adult Temperament Questionnaire measures. Quantity and severity of injury, as well as playing time missed, were tracked for 18 weeks. Results: On average, players experienced almost 6 injuries causing a loss of 10 playing days through the season. Those players scoring high on Boredom Susceptibility and Total Sensation-Seeking incurred more total injuries. Those scoring high on temperamental neutral perceptual sensitivity suffered more severe injuries. Conclusions: Athletes who suffered more injuries reported a preference for stimulating environments and boredom with non-stimulating environments. Injury severity was not correlated with sensation-seeking but was related to temperamental perceptual sensitivity. Implications for identification of injury-prone athletes, pre-injury training, and post-injury treatment are discussed.

  11. Manikin for assessment of MP3 player exposure

    DEFF Research Database (Denmark)

    Hammershøi, Dorte

    2007-01-01

    and adolescents in general. Even less is known about the affect on hearing, if any. With the purpose of mediating attention to the fact that music can cause hearing damage, a manikin for assessment of MP3 player exposure has been build. The manikin has an IEC 60711 simulator in one ear, a gumstix computer...

  12. Cogeneration: a winning game for the players who risk it

    Energy Technology Data Exchange (ETDEWEB)

    1985-11-01

    Cogeneration holds out the tantalizing prospect of lower utility rates and affordable energy. But the stakes are high. Now an expert player - the cogen developer - offers to negotiate the gameboard and guarantee a win to those willing to take a chance on his services.

  13. Inadequate pre-season preparation of schoolboy rugby players - a ...

    African Journals Online (AJOL)

    currently being evaluated in 25 of the 26 schools surveyed in the original study.3 ... by 471 players, an average of 1.9 concussion injuries per .... might spend a large amount of time on this and others not, ... Rugby football injunes, 1980-1983.

  14. Surveillance of injuries among Kenya Rugby Union (KRU) players ...

    African Journals Online (AJOL)

    (38.2%) and concussion (8.9%) (table4). The types of ... being linked with dangerous play. A player in KC ... that bigger body sizes are associated with higher rates of injuries (9, 15). ... football Br J Sports Med 1974; 8: 183-187. 3. Nicholl J P ...

  15. Raynaud´s phenomenon in a slap bass player

    DEFF Research Database (Denmark)

    Jepsen, Jørgen Riis; Simonsen, Jane Angel

    2016-01-01

    OBJECTIVE: Secondary Raynaud’s phenomenon is a frequent condition related to occupational exposure to local vibration but has not been described in musicians. This study aims to describe cold-induced blanching of the right second and (in particular) third digits in a 67-year-old double bass player...

  16. Role-player expectations regarding the education of nursing research

    Directory of Open Access Journals (Sweden)

    SCD Zeelie

    2003-09-01

    Full Text Available This article reports on role player expectations regarding the education of nursing research. The importance of the role player expectations are two-fold: firstly as a factor in the external environment influencing and guiding the formulation phase of the development of standards and secondly, due to the clear indications of problems regarding nursing research in the nursing profession in literature. The role player expectations were elicited using a qualitative, exploratory and contextual design. The role player population included nurse educators, nurses in managerial, clinical and research positions, students and the medical profession. The data was gathered using the naïve sketches and qualitative data analysis was done using Morse & Field’s approach (1996:103-107 in combination with Tesch’s data analysis approach as cited by Creswell (1994:154-156. Sixty initial categories were narrowed down to six final categories, which are the research learning programme, personnel, students, departmental policies, funding and support systems.

  17. Body size and composition of National Football League players.

    Science.gov (United States)

    Kraemer, William J; Torine, Jon C; Silvestre, Ricardo; French, Duncan N; Ratamess, Nicholas A; Spiering, Barry A; Hatfield, Disa L; Vingren, Jakob L; Volek, Jeff S

    2005-08-01

    The purpose of this study was to present a profile of body size and composition of National Football League (NFL) players prior to the start of the regular season. Fifty-three members of the Indianapolis Colts professional football team were measured for height, body mass, and percentage body fat using the BOD POD air-displacement plethysmography system during summer camp of the 2003 football season. These data were categorized by position for comparison with previous studies of NFL football players. The relationships observed were as follows (= represents nonsignificant; > represents p Linebackers > Running Backs = Wide Receivers = Defensive Backs. Body Mass: Offensive Line = Defensive Line > Tight Ends = Linebackers > Running Backs = Quarterbacks/ Kickers/Punters > Wide Receivers = Defensive Backs. Percentage Body Fat: Offensive Line > Defensive Line > Quarterbacks/ Kickers/Punters = Linebackers = Tight Ends > Running Backs = Wide Receivers = Defensive Backs. Comparisons to teams in the 1970s indicate that body mass has increased only for offensive and defensive linemen; however, height and body fat among player positions have not dramatically changed. Furthermore, the body mass index is not an accurate measure or representation of body fat or obesity in NFL players. These data provide a basic template for size profiles and differences among various positions and allow comparisons with other studies for changes in the NFL over the past 3 decades.

  18. Analysis of football player's motion in view of fractional calculus

    Science.gov (United States)

    Couceiro, Micael; Clemente, Filipe; Martins, Fernando

    2013-06-01

    Accurately retrieving the position of football players over time may lay the foundations for a whole series of possible new performance metrics for coaches and assistants. Despite the recent developments of automatic tracking systems, the misclassification problem (i.e., misleading a given player by another) still exists and requires human operators as final evaluators. This paper proposes an adaptive fractional calculus (FC) approach to improve the accuracy of tracking methods by estimating the position of players based on their trajectory so far. One half-time of an official football match was used to evaluate the accuracy of the proposed approach under different sampling periods of 250, 500 and 1000 ms. Moreover, the performance of the FC approach was compared with position-based and velocity-based methods. The experimental evaluation shows that the FC method presents a high classification accuracy for small sampling periods. Such results suggest that fractional dynamics may fit the trajectory of football players, thus being useful to increase the autonomy of tracking systems.

  19. Pectoralis major ruptures in professional American football players.

    Science.gov (United States)

    Tarity, T David; Garrigues, Grant E; Ciccotti, Michael G; Zooker, Chad C; Cohen, Steven B; Frederick, Robert W; Williams, Gerald R; DeLuca, Peter F; Dodson, Christopher C

    2014-09-01

    Pectoralis major injuries are an infrequent shoulder injury that can result in pain, weakness, and deformity. These injuries may occur during the course of an athletic competition, including football. The purpose of this study was to determine the incidence of pectoralis major ruptures in professional football players and time lost from the sport following injury. We hypothesized that ruptures most frequently occur during bench-press strength training. The National Football League Injury Surveillance System was reviewed for all pectoralis major injuries in all players from 2000 to 2010. Details regarding injury setting, player demographics, method of treatment, and time lost were recorded. A total of 10 injuries-complete ruptures-were identified during this period. Five of the 10 were sustained in defensive players, generally while tackling. Nine occurred during game situations, and 1 occurred during practice. Specific data pertinent to the practice injury was not available. No rupture occurred during weight lifting. Eight ruptures were treated operatively, and 2 cases did not report the method of definitive treatment. The average days lost was 111 days (range, 42-189). The incidence was 0.004 pectoralis major ruptures during the 11-year study period. Pectoralis major injuries are uncommon while playing football. In the National Football League, these injuries primarily occur not during practice or while bench pressing but rather during games. When pectoralis major ruptures do occur, they are successfully treated operatively. Surgery may allow for return to full sports participation. IV, case series.

  20. Wireless nanosensors for monitoring concussion of football players

    Science.gov (United States)

    Ramasamy, Mouli; Harbaugh, Robert E.; Varadan, Vijay K.

    2015-04-01

    Football players are more to violent impacts and injuries more than any athlete in any other sport. Concussion or mild traumatic brain injuries were one of the lesser known sports injuries until the last decade. With the advent of modern technologies in medical and engineering disciplines, people are now more aware of concussion detection and prevention. These concussions are often overlooked by football players themselves. The cumulative effect of these mild traumatic brain injuries can cause long-term residual brain dysfunctions. The principle of concussion is based the movement of the brain in the neurocranium and viscerocranium. The brain is encapsulated by the cerebrospinal fluid which acts as a protective layer for the brain. This fluid can protect the brain against minor movements, however, any rapid movements of the brain may mitigate the protective capability of the cerebrospinal fluid. In this paper, we propose a wireless health monitoring helmet that addresses the concerns of the current monitoring methods - it is non-invasive for a football player as helmet is not an additional gear, it is efficient in performance as it is equipped with EEG nanosensors and 3D accelerometer, it does not restrict the movement of the user as it wirelessly communicates to the remote monitoring station, requirement of individual monitoring stations are not required for each player as the ZigBee protocol can couple multiple transmitters with one receiver. A helmet was developed and validated according to the above mentioned parameters.

  1. Movement Demands of Elite U20 International Rugby Union Players

    Science.gov (United States)

    Drawer, Scott; Eager, Robin; Taylor, Neil; Cook, Christian

    2016-01-01

    The purpose of this study was to quantify movement demands of elite international age grade (U20) rugby union players during competitive tournament match play. Forty elite professional players from an U20 international performance squad were monitored using 10Hz global positioning systems (GPS) during 15 international tournament matches during the 2014/15 and 2015/16 seasons. Data on distances, velocities, accelerations, decelerations, high metabolic load (HML) distance and efforts, and number of sprints were derived. Data files from players who played over 60 min (n = 161) were separated firstly into Forwards and Backs, and more specifically into six positional groups; FR—Front Row (prop & hooker), SR—Second Row, BR—Back Row (Flankers & No.8), HB—Half Backs (scrum half & outside half), MF—Midfield (centres), B3 –Back Three (wings & full back) for match analysis. Analysis revealed significant differences between forwards and backs positions. Backs scored higher on all variables measured with the exception of number of moderate accelerations, decelerations (no difference). The centres covered the greatest total distance with the front row covering the least (6.51 ± 0.71 vs 4.97 ± 0.75 km, p rugby union players specific to positional roles. PMID:27055230

  2. Long-term training adaptations in elite male volleyball players.

    Science.gov (United States)

    Sheppard, Jeremy M; Newton, Robert U

    2012-08-01

    Several investigations have demonstrated differences in anthropometry, jump performance, and strength variables between developmental and elite-level volleyball players. However, within the elite level of play, the magnitude of change that can occur with training is unclear. The purpose of this investigation was to examine the anthropometric, vertical jump, and strength quality changes over 2 years in a group of national team volleyball players. Fourteen national team volleyball players (age, 23.0 ± 4.1 years; height, 1.98 ± 0.07 m; weight, 91.7 ± 7.9 kg) began and completed this study. Participants had all played international matches (representing Australia) before the examination time period and continued to do so during the international season. Anthropometry (stature, mass, and sum of 7 skinfolds), vertical jump measures (countermovement vertical jump; depth jump from 0.35 m, DJ; spike jump, SPJ, all including arm swing), and lower-body power (jump squat at body mass, and jump squat + 50% body weight, JS50) measures were tested before and at the conclusion of the investigation period. Significant (p 0.70) in the sum of 7 skinfolds reduction, SPJ, and leg extensor power. This study has demonstrated that elite male volleyball players can improve leanness and power, which contribute to improvements in vertical jump.

  3. Tales of the Unexpected: Coping among Female Collegiate Volleyball Players

    Science.gov (United States)

    Holt, Nicholas L.; Berg, Kylie-Joy; Tamminen, Katherine A.

    2007-01-01

    The purpose of this study was to examine patterns of appraisal, coping, and coping effectiveness in sport. Ten players from a collegiate female volleyball team were interviewed on two occasions, first in the week before a provincial final playoff tournament and in the week following the tournament. Data were transcribed verbatim and subjected to…

  4. meIRL-BC: Predicting Player Positions in Video Games

    NARCIS (Netherlands)

    Becht, I.; Bakkes, S.; Barnes, T.; Bogost, I.

    2014-01-01

    In this paper we demonstrate how behaviour-classification models can improve player position prediction for video game AI. To this end, we propose a novel method named meIRL-BC, which (1) uses maximum-entropy Inverse Reinforcement Learning for the creation of position prediction models [15], and (2)

  5. Organizational Gameplay: The Player as Designer of Character Organizations

    Directory of Open Access Journals (Sweden)

    Luciano R. Coutinho

    2015-01-01

    Full Text Available Looking at the ways in which players interact with computer games (the gameplays, we perceive predominance of character-centered and/or microcontrolled modes of interaction. Despite being well established, these gameplays tend to structure the games in terms of challenges to be fulfilled on an individual basis, or by thinking collectively but having to microcontrol several characters at the same time. From this observation, the paper presents a complementary gameplay in which the player is urged to face collective challenges by designing character organizations. The basic idea is to make the player structure and control group of characters by defining organizational specifications (i.e., definitions of roles, collective strategies, and social norms. During the game, commanded by the player, artificial agents are then instantiated to play the roles and to follow the strategies and norms as defined in the organizational specification. To turn the idea into practice, the paper proposes an abstract architecture comprising three components or layers. This architecture is materialized in a proof of concept prototype that combines the Minecraft game server, JADE agent platform, and MOISE+ organizational model. Variations and possibilities are discussed and the proposal is compared to related work in the literature.

  6. Game Play Schemas: From Player Analysis to Adaptive Game Mechanics

    Directory of Open Access Journals (Sweden)

    Craig A. Lindley

    2008-01-01

    Full Text Available Schema theory provides a foundation for the analysis of game play patterns created by players during their interaction with a game. Schema models derived from the analysis of play provide a rich explanatory framework for the cognitive processes underlying game play, as well as detailed hypotheses for the hierarchical structure of pleasures and rewards motivating players. Game engagement is accounted for as a process of schema selection or development, while immersion is explained in terms of levels of attentional demand in schema execution. However, schemas may not only be used to describe play, but might be used actively as cognitive models within a game engine. Predesigned schema models are knowledge representations constituting anticipated or desired learned cognitive outcomes of play. Automated analysis of player schemas and comparison with predesigned target schemas can provide a foundation for a game engine adapting or tuning game mechanics to achieve specific effects of engagement, immersion, and cognitive skill acquisition by players. Hence, schema models may enhance the play experience as well as provide a foundation for achieving explicitly represented pedagogical or therapeutic functions of games.

  7. Deploying music characteristics for an affective music player

    NARCIS (Netherlands)

    van der Zwaag, Marjolein D.; Westerink, Joyce H.D.M.; van den Broek, Egon; Cohn, Jeffrey; Nijholt, Antinus; Pantic, Maja

    2009-01-01

    This paper describes work toward an affective music player (AMP), which is able to direct affect to a goal state by selecting music. Repeatedly, music has been shown to modulate affect; however, precise guidelines for the use of music characteristics in an AMP have not been defined. To explore these

  8. "Badminton Player-Coach" Interactions between Failing Students

    Science.gov (United States)

    Mascret, Nicolas

    2011-01-01

    Background: Physical education teachers often use the player-coach dyad in individual opposition sports so that students can obtain information on their actions and then better regulate them. This type of work also develops methodological and social skills. However, the task of observing a partner often poses problems for failing students, who…

  9. Deploying music characteristics for an affective music player

    NARCIS (Netherlands)

    Zwaag, van der Marjolein D.; Westerink, Joyce H.D.M.; Broek, van den Egon L.; Cohn, Jeffrey; Nijholt, Anton; Pantic, Maja

    2009-01-01

    This paper describes work toward an affective music player (AMP), which is able to direct affect to a goal state by selecting music. Repeatedly, music has been shown to modulate affect; however, precise guidelines for the use of music characteristics in an AMP have not been defined. To explore these

  10. Development of Repeated Sprint Ability in Talented Youth Basketball Players

    NARCIS (Netherlands)

    te Wierike, Sanne C. M.; de Jong, Mark C.; Tromp, Eveline J. Y.; Vuijk, Pieter J.; Lemmink, Koen A. P. M.; Malina, Robert M.; Elferink-Gemser, Marije T.; Visscher, Chris

    2014-01-01

    te Wierike, SCM, de Jong, MC, Tromp, EJY, Vuijk, PJ, Lemmink, KAPM, Malina, RM, Elferink-Gemser, MT, and Visscher, C. Development of repeated sprint ability in talented youth basketball players. J Strength Cond Res 28(4): 928-934, 2014-Factors affecting repeated sprint ability (RSA) were evaluated i

  11. Hand Grip Strength Vs. Sprint Effectiveness in Amputee Soccer Players

    Directory of Open Access Journals (Sweden)

    Wieczorek Marta

    2015-12-01

    Full Text Available Amputee soccer is one of the types of soccer designed for the disabled, especially those who have undergone amputations, as well as those with extremity dysfunction. The objective of the study was to find the relationship between hand grip strength and sprint time in amputee soccer players. Thirteen field amputee soccer players participated in the study. A SAEHAN hydraulic hand dynamometer manufactured by Jamar was used for hand grip strength measurements. The sprint running test was conducted over a distance of 30 m. The Fusion Smart Speed System was employed for running time measurements. No statistically significant relationships were found between hand grip strength of the left or right hand, and sprint times over 1, 5, 10, 15, 20, 25 and 30 m. Analysis of the running velocity curve of the subjects showed an interesting profile characterized by a 15 meter-long acceleration phase and a significant velocity increase over a distance of 20 – 25 m. The study suggests that there is no relationship between hand grip strength and sprint effectiveness in amputee soccer players. The specificity of locomotion with the use of elbow crutches among elite Polish amputee soccer players probably accounts for the profile of the sprint velocity curve. Extension of the acceleration phase in the sprint run and a velocity increase in the subsequent part of the run were observed.

  12. Computing sequential equilibria for two-player games

    DEFF Research Database (Denmark)

    Miltersen, Peter Bro

    2006-01-01

    Koller, Megiddo and von Stengel showed how to efficiently compute minimax strategies for two-player extensive-form zero-sum games with imperfect information but perfect recall using linear programming and avoiding conversion to normal form. Their algorithm has been used by AI researchers for cons...

  13. Increasing mouthguards usage among junior rugby and basketball players.

    Science.gov (United States)

    Jalleh, G; Donovan, R J; Clarkson, J; March, K; Foster, M; Giles-Corti, B

    2001-06-01

    To evaluate a Western Australian mouthguard promotion campaign, launched at the start of the 1997/98 junior rugby union and junior basketball seasons, aimed at increasing mouthguard usage at competition and training. A quasi-experimental field design was used to assess the impact of the mouthguard campaign on behavioural change. Observational data were collected pre- and post-campaign on mouthguard usage by players present at a rugby and basketball competition event and at a training session. Junior Australian Rules Football players were used as a control group. Pre-post observational surveys showed a significantly greater increase in mouthguard usage in competition games among rugby union (77% to 84%) and basketball players (23% to 43%) compared with the control group (72% to 73%). All codes showed a post-campaign increase in mouthguard usage at training, but the intervention codes' increases were greater than the control's increase (rugby union: 29% to 40%; basketball: 11% to 36%; football: 34% to 40%). The campaign had a significant and substantial effect on behaviour and provides evidence of the benefits of leveraging a sponsorship to modify the behaviour of the target group. This campaign provides a model for promoting mouthguard usage in other sports among junior players.

  14. Foot posture and patellar tendon pain among adult volleyball players

    NARCIS (Netherlands)

    Groot, R. de; Malliaras, P.; Munteanu, S.; Payne, C.; Morrissey, D.; Maffulli, N.

    2012-01-01

    OBJECTIVE: We hypothesized that individuals with a normal foot posture would be less likely to experience patellar tendon pain and pathology than those with a pronated or supinated foot. DESIGN: Observational study. SETTING: Field-based study among competing athletes. PARTICIPANTS: Volleyball player

  15. Tales of the Unexpected: Coping among Female Collegiate Volleyball Players

    Science.gov (United States)

    Holt, Nicholas L.; Berg, Kylie-Joy; Tamminen, Katherine A.

    2007-01-01

    The purpose of this study was to examine patterns of appraisal, coping, and coping effectiveness in sport. Ten players from a collegiate female volleyball team were interviewed on two occasions, first in the week before a provincial final playoff tournament and in the week following the tournament. Data were transcribed verbatim and subjected to…

  16. Foot Posture and Patellar Tendon Pain Among Adult Volleyball Players

    NARCIS (Netherlands)

    de Groot, Reinier; Malliaras, Peter; Munteanu, Shannon; Payne, Craig; Morrissey, Dylan; Maffulli, Nicola

    2012-01-01

    Objective: We hypothesized that individuals with a normal foot posture would be less likely to experience patellar tendon pain and pathology than those with a pronated or supinated foot. Design: Observational study. Setting: Field-based study among competing athletes. Participants: Volleyball player

  17. Older Amateur Keyboard Players Learning for Self-Fulfilment

    Science.gov (United States)

    Taylor, Angela

    2011-01-01

    This article investigates self-reported music learning experiences of 21 older amateur pianists and electronic keyboard players. Significant changes in their lives and the encouragement of friends were catalysts for returning to or taking up a keyboard instrument as an adult, although not all returners had positive memories of learning a keyboard…

  18. Older Amateur Keyboard Players Learning for Self-Fulfilment

    Science.gov (United States)

    Taylor, Angela

    2011-01-01

    This article investigates self-reported music learning experiences of 21 older amateur pianists and electronic keyboard players. Significant changes in their lives and the encouragement of friends were catalysts for returning to or taking up a keyboard instrument as an adult, although not all returners had positive memories of learning a keyboard…

  19. Development of Repeated Sprint Ability in Talented Youth Basketball Players

    NARCIS (Netherlands)

    te Wierike, Sanne C. M.; de Jong, Mark C.; Tromp, Eveline J. Y.; Vuijk, Pieter J.; Lemmink, Koen A. P. M.; Malina, Robert M.; Elferink-Gemser, Marije T.; Visscher, Chris

    2014-01-01

    te Wierike, SCM, de Jong, MC, Tromp, EJY, Vuijk, PJ, Lemmink, KAPM, Malina, RM, Elferink-Gemser, MT, and Visscher, C. Development of repeated sprint ability in talented youth basketball players. J Strength Cond Res 28(4): 928-934, 2014-Factors affecting repeated sprint ability (RSA) were evaluated i

  20. College Students' Usage of Personal Music Players (PMP) during Exercise

    Science.gov (United States)

    Barney, David; Gust, Anita; Liguori, Gary

    2012-01-01

    The purpose of this study was to investigate the use of personal music players (PMPs) during exercise, including their purpose(s), how they affect exercise, and the most common music listened to. A representative sample of 184 undergraduate students from two separate university wellness centers completed a 17-item, content validated questionnaire…

  1. Pro Football: Do Players Pay With Their Health?

    Science.gov (United States)

    Groves, D

    1989-01-01

    The hits and injuries, playing hurt, high-fat diets, and the use of anabolic-androgenic steroids may lead to serious health problems for professional football players. Are those problems an unavoidable part of the game, or can they be minimized or prevented?

  2. Different injury pattern in goalkeepers compared to field players

    DEFF Research Database (Denmark)

    Eirale, Cristiano; Tol, Johannes L; Whiteley, Rod

    2014-01-01

    Goalkeepers have a specific physiological and biomechanical profile including hip loading with increased frontal plane kinetics and explosive side jumps. The aim of this study is to analyze the injury incidence in professional goalkeepers and to compare this with field players....

  3. Computing sequential equilibria for two-player games

    DEFF Research Database (Denmark)

    Miltersen, Peter Bro

    2006-01-01

    Koller, Megiddo and von Stengel showed how to efficiently compute minimax strategies for two-player extensive-form zero-sum games with imperfect information but perfect recall using linear programming and avoiding conversion to normal form. Their algorithm has been used by AI researchers for cons...

  4. Medium-term Mortality of Dutch Professional Soccer Players

    NARCIS (Netherlands)

    Koning, Ruud H.; Amelink, Remko

    Professional athletes such as soccer players are expected to be in better health than the average member of their age cohort, if only because of the very demands imposed on them by their profession. Moreover, during their active career, their health is monitored on a regular basis. However, whenever

  5. Aerobic Development of Elite Youth Ice Hockey Players.

    Science.gov (United States)

    Leiter, Jeff R; Cordingley, Dean M; MacDonald, Peter B

    2015-11-01

    Ice hockey is a physiologically complex sport requiring aerobic and anaerobic energy metabolism. College and professional teams often test aerobic fitness; however, there is a paucity of information regarding aerobic fitness of elite youth players. Without this knowledge, training of youth athletes to meet the standards of older age groups and higher levels of hockey may be random, inefficient, and or effective. Therefore, the purpose of this study was to determine the aerobic fitness of elite youth hockey players. A retrospective database review was performed for 200 male AAA hockey players between the ages of 13 and 17 (age, 14.4 ± 1.2 years; height, 174.3 ± 8.5 cm; body mass, 67.2 ± 11.5 kg; body fat, 9.8 ± 3.5%) before the 2012-13 season. All subjects performed a graded exercise test on a cycle ergometer, whereas expired air was collected by either a Parvo Medics TrueOne 2400 or a CareFusion Oxycon Mobile metabolic cart to determine maximal oxygen consumption (V[Combining Dot Above]O2max). Body mass, absolute V[Combining Dot Above]O2max, and the power output achieved during the last completed stage increased in successive age groups from age 13 to 15 years (p ≤ 0.05). Ventilatory threshold (VT) expressed as a percentage of V[Combining Dot Above]O2max and the heart rate (HR) at which VT occurred decreased between the ages of 13 and 14 years (p ≤ 0.05), whereas the V[Combining Dot Above]O2 at which VT occurred increased from the age of 14-15 years. There were no changes in relative V[Combining Dot Above]O2max or HRmax between any successive age groups. The aerobic fitness levels of elite youth ice hockey players increased as players age and mature physically and physiologically. However, aerobic fitness increased to a lesser extent at older ages. This information has the potential to influence off-season training and maximize the aerobic fitness of elite amateur hockey players, so that these players can meet standards set by advanced elite age groups.

  6. Abdominal body composition differences in NFL football players.

    Science.gov (United States)

    Bosch, Tyler A; Burruss, T Pepper; Weir, Nate L; Fielding, Kurt A; Engel, Bryan E; Weston, Todd D; Dengel, Donald R

    2014-12-01

    The purpose of this study was to examine visceral fat mass as well as other measures abdominal body composition in National Football League (NFL) players before the start of the season. Three hundred and seventy NFL football players were measured before the start of the season using dual-energy x-ray absorptiometry. Regional fat and lean mass was measured for each player. Players were categorized into 3 groups based on positions that mirror each other: linemen; linebackers/tight ends/running backs and wide receivers/defensive backs. Significant differences were observed between the position groups for both lean and fat regional measurements. However, the magnitude of difference was much greater for fat measures than lean measures. Additionally, a threshold was observed (∼114 kg) at which there is a greater increase in fat accumulation than lean mass accumulation. The increase in fat accumulation is distributed to the abdominal region where thresholds were observed for subcutaneous abdominal fat accumulation (12.1% body fat) and visceral abdominal fat accumulation (20.1% body fat), which likely explains the regional fat differences between groups. The results of this study suggest that as players get larger, there is more total fat than total lean mass accumulation and more fat is distributed to the abdominal region. This is of importance as increased fat mass may be detrimental to performance at certain positions. The thresholds observed for increased abdominal fat accumulation should be monitored closely given recent research observed that abdominal obesity predicts lower extremity injury risk and visceral adipose tissue's established association with cardiometabolic risk.

  7. Concussion Frequency Associates with Musculoskeletal Injury in Retired NFL Players.

    Science.gov (United States)

    Pietrosimone, Brian; Golightly, Yvonne M; Mihalik, Jason P; Guskiewicz, Kevin M

    2015-11-01

    Concussion is commonly associated with immediate and persistent alterations in motor function affecting postural control and gait. Patients with lower extremity joint injury have demonstrated functional alterations in the cerebral cortex, suggesting that musculoskeletal injury may be linked to alterations in brain function. Therefore, we examined the associations between concussion frequency and lower extremity musculoskeletal injury sustained during professional careers of National Football League (NFL) players in a cross-sectional study. An inclusive health history survey was mailed to 3647 NFL players who retired during 1930-2001. Respondents reported total concussion frequency (zero, one, two, or three or more) and presence (yes/no) of specific knee and ankle musculoskeletal injury during their NFL career. Separate logistic regression models were used to estimate associations between concussion frequency and each musculoskeletal injury type, adjusting for number of years played in the NFL, body mass index while playing in the NFL, and playing position. Data from 2429 players (66.6% response rate) were available for analysis. Nearly 61% reported experiencing a concussion while competing in the NFL. Meniscal tear was the most commonly reported musculoskeletal injury (32%). Compared with NFL players who did not sustain a concussion, retired NFL players with one, two, or three or more concussions had between 18% and 63%, 15% and 126%, and 73% and 165% higher odds of reporting various musculoskeletal injuries, respectively. A history of concussions was associated with a history of musculoskeletal injuries during NFL careers. These data suggest that a higher number of concussions is linked with higher odds of reporting a musculoskeletal injury.

  8. Sprint, agility, strength and endurance capacity in wheelchair basketball players

    Directory of Open Access Journals (Sweden)

    Javier Yanci

    2014-11-01

    Full Text Available The aims of the present study were, firstly, to determine the reliability and reproducibility of an agility T-test and Yo-Yo 10 m recovery test; and secondly, to analyse the physical characteristics measured by sprint, agility, strength and endurance field tests in wheelchair basketball (WB players. 16 WB players (33.06 ± 7.36 years, 71.89 ± 21.71 kg and sitting body height 86.07 ± 6.82 cm belonging to the national WB league participated in this study. Wheelchair sprint (5 and 20 m without ball, and 5 and 20 m with ball agility (T-test and pick-up test strength (handgrip and maximal pass and endurance (Yo-Yo 10 m recovery test were performed. T-test and Yo-Yo 10 m recovery test showed good reproducibility values (intraclass correlation coefficient, ICC = 0.74-0.94. The WB players’ results in 5 and 20 m sprints without a ball were 1.87 ± 0.21 s and 5.70 ± 0.43 s and with a ball 2.10 ± 0.30 s and 6.59 ± 0.61 s, being better than those reported in the literature. Regarding the pick-up test results (16.05 ± 0.52 s and maximal pass (8.39 ± 1.77 m, players showed worse values than those obtained in elite players. The main contribution of the present study is the characterization of the physical performance profile of WB players using a field test battery. Furthermore, we demonstrated that the agility T-test and the aerobic Yo-Yo 10 m recovery test are reliable; consequently they may be appropriate instruments for measuring physical fitness in WB.

  9. Aerobic fitness and performance in elite female futsal players

    Directory of Open Access Journals (Sweden)

    JC Barbero-Alvarez

    2016-01-01

    Full Text Available Despite its growing popularity, few studies have investigated specific physiological demands for elite female futsal. The aim of this study was to determine aerobic fitness in elite female futsal players using laboratory and field testing. Fourteen female futsal players from the Venezuelan National team (age =21.2±4.0 years; body mass =58.6±5.6 kg; height =161±5.0 cm performed a progressive maximal treadmill test under laboratory conditions. Players also performed a progressive intermittent futsal-specific field test for endurance, the Futsal Intermittent Endurance Test (FIET, until volitional fatigue. Outcome variables were exercise heart rate (HR, VO2, post-exercise blood lactate concentrations ([La]b and running speeds (km • h -2 . During the treadmill test, VO2max, maximal aerobic speed (MAS, HR and peak [La]b were 45.3±5.6 ml • kg-1 • min-1, 12.5±1.77 km • h -2 , 197±8 beats • min-1 and 11.3±1.4 mmol • l-1, respectively. The FIET total distance, peak running velocity, peak HR and [La]b were 1125.0±121.0 m, 15.2±0.5 km • h -2 , 199±8 beats • min-1 and 2.5±2.2 mmol • l-1, respectively. The FIET distance and peak speed were strongly associated (r= 0.85-87, p<0.0001 with VO2max and MAS, respectively. Peak HR and [La]b were not significantly different between tests. Elite female futsal players possess moderate aerobic fitness. Furthermore, the FIET can be considered as a valid field test to determine aerobic fitness in elite level female futsal players.

  10. Athletic Cardiac Remodeling in US Professional Basketball Players.

    Science.gov (United States)

    Engel, David J; Schwartz, Allan; Homma, Shunichi

    2016-04-01

    The incidence of sudden cardiac death is higher in US basketball players compared with other athlete groups. However, the recognition of the risk for sudden cardiac death among basketball players is challenging because little is known regarding athletic cardiac remodeling in these athletes or athletes of similarly increased size. To perform a comprehensive cardiac structural analysis of National Basketball Association (NBA) professional athletes. Echocardiographic observational study of NBA players on the active rosters for the 2013-2014 and 2014-2015 seasons was performed from December 16, 2013, to December 12, 2014. The policy of the NBA mandates annual preseason stress echocardiograms for each player. The NBA has sanctioned Columbia University Medical Center to conduct annual health and safety reviews of these echocardiograms. Data were analyzed from January to May 2015. Cardiac variables assessed included left ventricular (LV) size, mass, wall thickness, and hypertrophy patterns and function; left atrial volume; and aortic root diameter. All dimensions were biometrically scaled. Of the 526 athletes included in the study, 406 (77.2%) were African American and 107 (20.3%) were white, with a mean (SD) age of 25.7 (4.3) years. Mean (SD) athlete height was 200.2 (8.8) cm; mean body surface area, 2.38 (0.19) m2. Left ventricular size and mass in NBA athletes were proportional to body size, extending to the uppermost biometrics of the cohort. Left ventricular hypertrophy was present in 144 athletes (27.4%). African American athletes had increased LV wall thickness (unadjusted mean, 11.2 mm; 95% CI, 11.1-11.3 mm) and LV mass (unadjusted mean, 106.3 g/m2; 95% CI, 104.6-108.0 g/m2) compared with LV wall thickness (unadjusted mean, 10.5 mm; 95% CI, 10.3-10.7 mm; P basketball players and the athletic community at large.

  11. Attributes of top elite team-handball players.

    Science.gov (United States)

    Massuça, Luís M; Fragoso, Isabel; Teles, Júlia

    2014-01-01

    Researchers in the field of excellence in sport performance are becoming increasingly focused on the study of sport-specific characteristics and requirements. In accordance with this, the purposes of this study were (a) to examine the morphologic-, fitness-, handball-specific skills and psychological and "biosocial" differences between top elite and nontop elite team-handball players and (b) to investigate the extent to which they may be used to identify top elite team-handball players. One hundred sixty-seven adult male team-handball players were studied and divided in 2 groups: top elite (n = 41) and nontop elite (n = 126). Twenty-eight morphologic-, 9 fitness-, 1 handball-specific skills and 2 psychological-based and 2 "biosocial"-based attributes were used. Top elite and nontop elite groups were compared for each variable of interest using Student's t-test, and 5 logistic regression analyses were performed with the athlete's performance group (top elite or nontop elite) as the dependent variable and the variables of each category as predictors. The results showed that (a) body mass, waist girth, radiale-dactylion length, midstylion-dactylion length, and absolute muscle mass (morphologic model); (b) 30-m sprint time, countermovement jump height and average power, abdominal strength and the class of performance in the Yo-Yo Intermittent Endurance Test (fitness model); (c) offensive power (specific-skills model); (d) ego-based motivational orientation (psychological model); (e) socioeconomic status and the energy spent (for week) in handball activity (biosocial model); significantly (p handball player. Moreover, the fitness model exhibited higher percentages of correct classification (i.e., 91.5%) than all the other models did. This study provided (a) the rational to reduce the battery of tests for evaluation purposes, and (b) the initial step to work on building a multidisciplinary model to predict the probability of a handball athlete to be a top elite player.

  12. Aerobic fitness and performance in elite female futsal players

    Science.gov (United States)

    Subiela, JV; Granda-Vera, J; Castagna, C; Gómez, M; Del Coso, J

    2015-01-01

    Despite its growing popularity, few studies have investigated specific physiological demands for elite female futsal. The aim of this study was to determine aerobic fitness in elite female futsal players using laboratory and field testing. Fourteen female futsal players from the Venezuelan National team (age =21.2±4.0 years; body mass =58.6±5.6 kg; height =161±5.0 cm) performed a progressive maximal treadmill test under laboratory conditions. Players also performed a progressive intermittent futsal-specific field test for endurance, the Futsal Intermittent Endurance Test (FIET), until volitional fatigue. Outcome variables were exercise heart rate (HR), VO2, post-exercise blood lactate concentrations ([La]b) and running speeds (km · h-1). During the treadmill test, VO2max, maximal aerobic speed (MAS), HR and peak [La]b were 45.3±5.6 ml · kg-1 · min-1, 12.5±1.77 km · h-1, 197±8 beats · min-1 and 11.3±1.4 mmol · l-1, respectively. The FIET total distance, peak running velocity, peak HR and [La]b were 1125.0±121.0 m, 15.2±0.5 km · h-1, 199±8 beats · min-1 and 12.5±2.2 mmol · l-1, respectively. The FIET distance and peak speed were strongly associated (r= 0.85-87, p < 0.0001) with VO2max and MAS, respectively. Peak HR and [La]b were not significantly different between tests. Elite female futsal players possess moderate aerobic fitness. Furthermore, the FIET can be considered as a valid field test to determine aerobic fitness in elite level female futsal players. PMID:28479664

  13. Variation in the Ace Gene in Elite Polish Football Players

    Directory of Open Access Journals (Sweden)

    Cięszczyk Paweł

    2016-12-01

    Full Text Available Purpose. A common polymorphism in the angiotensin converting enzyme I gene (the ACE I/D variant represents one of the first characterized and the most widely studied genetic variants in the context of elite athletes status and performance related traits. The aim of the study was to determine the genotype and allele distribution of the allele and genotype of the ACE gene in Polish male football players. Methods. The total of 106 Polish male professional football players were recruited. They were divided into groups according to the position in the field: forwards, defenders, midfielders, and goalkeepers. For controls, samples were prepared with 115 unrelated volunteers. DNA was extracted from the buccal cells donated by the subjects, and the PCR amplification of the polymorphic region of the ACE gene containing either the insertion (I or deletion (D fragment was performed. Results. The genotype distribution and allele frequencies among all football players did not differ significantly when compared with sedentary control individuals (p = 0.887, p = 0.999, respectively. Likewise, the analysis of forwards, defenders, midfielders, and goalkeepers revealed no significant differences in either ACE genotype or allele frequencies. Conclusions. We did not provide evidence for difference of variation of the ACE I/D polymorphism between Polish football players and controls, as we did not obtain any statistically significantly higher frequency of either of the analysed alleles (I and D or genotypes (DD, ID, and II in the studied subgroups. It may be suspected that harbouring of I/D allelic variants of the ACE gene neither decreases nor increases the probability of being a professional football player in Poland.

  14. Physical Characteristics Of Female Basketball Players According To Playing Position

    Directory of Open Access Journals (Sweden)

    Kucsa Richard

    2015-05-01

    Full Text Available Physical characteristics play an important role in the selection of young basketball players and the progress in their playing performance. The aim of the study was to analyze differences in chosen physical characteristics of Slovak U17 female basketball players with respect to their playing positions. We assumed, that there will be statistically significant differences between playing positions in each performance tests results. Chosen characteristics were analyzed for 14 players (mean/SD, age 16.34±0.82; body height 179.72±8.04 cm; body weight 67.62±7.10 kg; body fat 16.59±2.04 %; VO2max 46.20±4.71 ml.kg−1.min−1 according to their playing positions (guard, forward, center. Five specific performance tests for each player were conducted as a 3/4 Basketball court sprint, 10 × 5m Shuttle test, Lane agility drill, No-step vertical jump and Maximum vertical jump. The differences in tests results by playing positions were evaluated by one-way ANOVA. There were no significant differences found in results of chosen performance tests between playing positions (p>.05. In spite of fact, that there were no significant differences, we found interesting results between playing positions in physical characteristics. Guards had better results in speed (3.73±0.16 s, quickness (17.43±0.56 s and both lower-body power tests (47.16±3.06 cm; 57.00±3.40 cm than forwards and centers. Forwards had the best results in agility test (12.54±0.43 s. The results of this study produce useful information about physical characteristics of young basketball players according to their playing position and help to diagnose and improve their performance.

  15. Soccer Players Cultural Capital and Its Impact on Migration

    Science.gov (United States)

    Leskošek, Bojan; Vodičar, Janez; Topič, Mojca Doupona

    2016-01-01

    Abstract The purpose of this study was to identify factors that constituted the cultural capital among soccer players. We assumed that in the increasingly globalized world of professional soccer, a player’s success would often depend on migrating and adjusting to life in other countries. Willingness to migrate and successful adjustment are tied to player’s previous attitudes and/or behaviours (habitus), significant support from others, including family members, and previous experiences and success in sports and education. Our hypothesised model of the cultural capital was based on the Pierre Bourdieu’s theoretical framework. It consisted of 26 variables related to three sets of factors: soccer experiences, a family context and support, and educational achievements of the players and their parents. The model was tested using a sample of 79 current soccer coaches who also had been players at the elite level. A factor analysis was used to empirically verify the content of the hypothetical model of the soccer players’ cultural capital. Nine latent factors were extracted and together, they accounted for 55.01% of the total model variance. Individual factors obtained showed a sufficient level of substantial connection. The Cronbach’s alpha value of 0.77 confirmed the internal consistency of the operationalised variables in the hypothetical model. In addition, the impact of these aforementioned life dimensions on the migration of soccer players was studied. The results of the binary logistic regression analysis showed that the first factor of the hypothetical model (F1) had 2.2 times and the second factor (F8) had 3.9 times higher odds for migration abroad. Sociocultural findings using this new assessment approach could help create better “success conditions” in the talent development of young players. PMID:28031770

  16. Development of muscular imbalance in the shoulder girdle in volleyball players

    OpenAIRE

    VRBOVÁ, Lucie

    2011-01-01

    This bachelor?s thesis deals with the development of muscular imbalance in the shoulder girdle in volleyball players. The volleyball player?s shoulder is the most exposed and vulnerable joint. In addition, the way the sport has developed, the pressure on this joint has grown. Shoulder pain limits the player?s most important move: the strength and the power of the smash and the smash serve. This thesis consists of two parts: theoretical and a practical. The theoretical part deals with the anat...

  17. Locomotion Characteristics and Match-Induced Impairments in Physical Performance in Male Elite Team Handball Players

    DEFF Research Database (Denmark)

    Michalsik, L B; Aagaard, Peter; Madsen, Klavs

    2013-01-01

    The purpose of this study was to determine the physical demands and match-induced impairments in physical performance in male elite Team Handball (TH) players in relation to playing position. Male elite TH field players were closely observed during 6 competitive seasons. Each player (wing players......: WP, pivots: PV, backcourt players: BP) was evaluated during match-play using video recording and subsequently performing locomotion match analysis. A total distance of 3 627±568 m (group means±SD) was covered per match with a total effective playing time (TPT) of 53:51±5:52 min:s, while full...

  18. Protective equipment and player characteristics associated with the incidence of sport-related concussion in high school football players: a multifactorial prospective study.

    Science.gov (United States)

    McGuine, Timothy A; Hetzel, Scott; McCrea, Michael; Brooks, M Alison

    2014-10-01

    The incidence of sport-related concussion (SRC) in high school football is well documented. However, limited prospective data are available regarding how player characteristics and protective equipment affect the incidence of SRC. To determine whether the type of protective equipment (helmet and mouth guard) and player characteristics affect the incidence of SRC in high school football players. Cohort study; Level of evidence, 2. Certified athletic trainers (ATs) at each high school recorded the type of helmet worn (brand, model, purchase year, and recondition status) by each player as well as information regarding players' demographics, type of mouth guard used, and history of SRC. The ATs also recorded the incidence and days lost from participation for each SRC. Incidence of SRC was compared for various helmets, type of mouth guard, history of SRC, and player demographics. A total of 2081 players (grades 9-12) enrolled during the 2012 and/or 2013 football seasons (2287 player-seasons) and participated in 134,437 football (practice or competition) exposures. Of these players, 206 (9%) sustained a total of 211 SRCs (1.56/1000 exposures). There was no difference in the incidence of SRC (number of helmets, % SRC [95% CI]) for players wearing Riddell (1171, 9.1% [7.6%-11.0%]), Schutt (680, 8.7% [6.7%-11.1%]), or Xenith (436, 9.2% [6.7%-12.4%]) helmets. Helmet age and recondition status did not affect the incidence of SRC. The rate of SRC (hazard ratio [HR]) was higher in players who wore a custom mouth guard (HR = 1.69 [95% CI, 1.20-2.37], P football players. Players who had sustained an SRC within the previous 12 months were more likely to sustain an SRC than were players without a history of SRC. Sports medicine providers who work with high school football players need to realize that factors other than the type of protective equipment worn affect the risk of SRC in high school players. © 2014 The Author(s).

  19. Comparison of some physical and physiologic properties of soccer players and badminton players of 10-12 years old group

    Directory of Open Access Journals (Sweden)

    Recep Kürkçü

    2009-03-01

    Full Text Available The purpose of this study is aimed to compare some physical characteristics and physiological characteristics of adult footballer and badminton players. The subjects of the study were footballer (18 boys and were badminton players (12 boys who were volunteer at primary school in Şanlıurfa. The volunteers', took part in this study, age, height and the body weight average is determined like this respectively:  Footballers: 11,77 ± 0,54 yıl, 151,40 ± 7,35 cm, 41,83 ± 10,27 kgBadminton players: ise11,58 ± 0,66 yıl, 147,37 ± 8,05 cm, 39,08 ± 9,56 kg    Systolic and diastolic blood pressure, VC, FVC, FEV1 sit-reach 30 meters sprint and left-right hand gripping strength of subjects were measured. The differences between findings which were obtained by measurements from footballers and badminton players were considered with using "t-test" on SPSS Windows 11.     According to the data, differences between age, height, body weight average, diastolic blood pressure VC, FVC, FEV1, sit-reach 30 meters sprint and left hand gripping strength were obtained pointless, in the mean time relaxing heart rate, and sit-reach test (P<0.01, systolic blood pressure and right hand gripping strength values were obtained purposeful on (P<0.05 level.     In conclusion,  physical and physiological characteristics of footballers and badminton players were affected by their sport branch furthermore, relaxing heart rate, systolic blood pressure, sit -reach 30 meters sprint, right hand gripping strength performance of footballers were obtained preferable.

  20. Performance following a first professional concussion among National Basketball Association players.

    Science.gov (United States)

    Yengo-Kahn, Aaron M; Zuckerman, Scott L; Stotts, Jeff; Zalneraitis, Brian H; Gardner, Ryan M; Kerr, Zachary Y; Solomon, Gary S

    2016-09-01

    Basketball is a physical game played on a hardwood floor among high-jumping athletes at risk for injury. It is currently unknown how sport-related concussion (SRC) affects player performance after injury among professional basketball players. The objective of this study was to explore the impact of SRC on basketball performance among National Basketball Association (NBA) players. A retrospective, archival cohort study was performed that compared NBA player performance following concussion to pre-concussive performance. A comprehensive NBA injury database, compiled from publically available sources, was queried for NBA players who suffered concussion from 2005-06 to 2014-15 (10 seasons). Intra-and inter-player analyses were performed against a matched control group of players who missed playing time for personal reasons. Following application of inclusion/exclusion criteria and a matching process, 51 concussed players and 51 control players were included in analysis. There were no statistically significant decrements in baseline to post-concussion performance metrics in intra-player or player vs. controls after 5 return games. Our findings suggest that at the NBA level, an athlete's performance in the initial 5 games following injury does not suffer from the after-effects of concussive injury. These results may be useful in counseling professional athletes following a concussion.