Science.gov

Sample records for 4-h shooting sports

  1. Acquisition, Custody, and Storage of Firearms Used in 4-H Shooting Sports Programs

    ERIC Educational Resources Information Center

    White, David J.; Smith, Jedediah D.

    2014-01-01

    Shooting sports has been a 4-H program offering since the 1930's. Tragic events related to the use of firearms as weapons have caused public and private entities to evaluate and consider the appropriateness of youth access to and usage of firearms. 4-H educators have the primary responsibility for managing the risk associated with shooting sports…

  2. Possession, Transportation, and Use of Firearms by Older Youth in 4-H Shooting Sports Programs

    ERIC Educational Resources Information Center

    White, David J.; Williver, S. Todd

    2014-01-01

    Thirty years ago we would think nothing of driving to school with a jackknife in our pocket or rifle in the gun rack. Since then, the practices of possessing, transporting, and using firearms have been limited by laws, rules, and public perception. Despite restrictions on youth, the Youth Handgun Safety Act does afford 4-H shooting sports members…

  3. 4-H Shooting Sports Hits the Mark with Youth-at-Risk.

    ERIC Educational Resources Information Center

    Sabo, Kenneth E.; Hamilton, Wendy V.

    1997-01-01

    A 4-H program in a public housing project in New Mexico involved at-risk youth in activities such as archery and other shooting sports. These activities were found to promote motivation, cognitive development, self-esteem, and responsibility. (SK)

  4. Learning Objectives for Shooting Sports Instruction. 554A: Using Measurable Criteria To Evaluate Performance.

    ERIC Educational Resources Information Center

    Benson, Delwin E.; Manning, Jan

    This publication contains objectives that range from basic shooting sports safety and proficiency to more specialized activities. They can be applied to hunter safety education, 4-H shooting sports, scouting, and club or community activities for youth or adults. The specific learning objectives in each list have been grouped into learning…

  5. Is there an influence of relative age on participation in non-physical sports activities? The example of shooting sports.

    PubMed

    Delorme, Nicolas; Raspaud, Michel

    2009-08-01

    The aims of this study were to test for the presence of a relative age effect among male (n = 119,715) and female (n = 12,823) members of the shooting sports federation, and to determine whether any such effect has an impact on dropout from the sport. For the boys and girls, the results show a uniform distribution of dropout. A relative age effect was not found for the girls, showing that in female shooting sports there is no such effect. For the males, a significant statistical relative age effect was not detected in the 18-20 and 13-14 year categories. However, a relative age effect was found among adults and the 11-12 and under 11 year categories. A significant "inverse" relative age effect was found for the 15-17 year group. Further qualitative research is needed to clarify which factors contribute to this asymmetric distribution of birth dates in French male shooting sports.

  6. The Binomial Distribution in Shooting

    ERIC Educational Resources Information Center

    Chalikias, Miltiadis S.

    2009-01-01

    The binomial distribution is used to predict the winner of the 49th International Shooting Sport Federation World Championship in double trap shooting held in 2006 in Zagreb, Croatia. The outcome of the competition was definitely unexpected.

  7. 4-H and Iowa.

    ERIC Educational Resources Information Center

    Gore, Deborah, Ed.

    1988-01-01

    This issue focuses on Iowa's role in the historical development of the 4-H youth program. "Roots in Iowa" and "Jessie Field Shambaugh: The Mother of 4-H" (J. Friedel) describes the rural Iowan roots of the 4-H program, which today is located in 80 different countries, and give the story of its founder. Jessie Shambaugh, a rural…

  8. Discover 4-H Clubs: The Essential Resource for 4-H

    ERIC Educational Resources Information Center

    MacArthur, Stacey; Nelson, Cindy; Brower, Naomi; Memmott, Margie; Peterson, Gaelynn

    2016-01-01

    Obstacles facing new 4-H volunteers include time constraints and difficulty finding project-specific information, resources, and opportunities available for club members. As a solution to these obstacles and an aid for assisting volunteers in becoming confident in delivering information to youth, content experts produced Discover 4-H Clubs, a…

  9. 4-H Club Goat Guide.

    ERIC Educational Resources Information Center

    Brown, R. Kipp

    This guide provides information for 4-H Club members who have decided on a club goat project. Topics include general information in the following areas: show rules; facilities and equipment (barns/sheds, fences, feeders, water containers, and equipment); selection (structural correctness, muscle, volume and capacity, style and balance, and growth…

  10. Duck shooting injuries in Southland, New Zealand.

    PubMed

    Watts, Martin; Densie, Ian

    2013-05-10

    Duck shooting is a common sport in New Zealand. The opening weekend is anticipated and celebrated, often with significant alcohol intake which is cause for concern, and potentially very dangerous. Hunters are annually warned about the dangers. There have been few duck shooting incidents which lead to injury or death. In the last decade two duck shooters in New Zealand have been killed, while 16 suffered non fatal gunshot injuries. We present a series of injuries identified during the 2012 duck shooting season in Southland Province.

  11. Adult 4-H Volunteer Empowerment in 4-H Youth Development Settings

    ERIC Educational Resources Information Center

    Olsen, Pamela

    2009-01-01

    The primary purpose of this study was to determine which factors related to adult 4-H volunteer empowerment in 4-H youth development settings. This study examined the relationship of adult 4-H volunteers' perceived leadership styles of Oregon 4-H Youth Development Educators (YDE) to the adult 4-H volunteer sense of empowerment. In addition,…

  12. Engaging Library Partners in 4-H Programming

    ERIC Educational Resources Information Center

    Fields, Nia Imani; Rafferty, Elizabeth

    2012-01-01

    When most people think about 4-H, they remember county fairs, livestock programs, and agricultural education. While these programs are still prominent, 4-H has grown in order to meet the growing demands of today's youth. The organization has expanded services and programs to serve rural, suburban, and urban youth in every state in the U.S. 4-H is…

  13. Strengthening 4-H by Analyzing Enrollment Data

    ERIC Educational Resources Information Center

    Hamilton, Stephen F.; Northern, Angela; Neff, Robert

    2014-01-01

    The study reported here used data from the ACCESS 4-H Enrollment System to gain insight into strengthening New York State's 4-H programming. Member enrollment lists from 2009 to 2012 were analyzed using Microsoft Excel to determine trends and dropout rates. The descriptive data indicate declining 4-H enrollment in recent years and peak enrollment…

  14. Lower Spine Screening in the Shooting Sports.

    ERIC Educational Resources Information Center

    Volski, Robert V.; And Others

    1986-01-01

    A questionnaire and screening test for posture and flexibility were designed and administered to 80 rifle and pistol shooters. Findings indicated that 78 percent had eperienced low back pain during competition and 63 percent afterward. (MT)

  15. National 4-H School Enrichment Survey.

    ERIC Educational Resources Information Center

    Diem, Keith G.

    2001-01-01

    A survey of 4-H school enrichment programs (813 responses) found that they reach large numbers of diverse youth and develop credibility with community and schools. Long-term programs such as 4-H clubs have proven effective in helping youth develop life skills, but Extension must carefully consider the purpose and consequences of diverting…

  16. Holding on to 4-H Leaders.

    ERIC Educational Resources Information Center

    Hass, Glen

    1979-01-01

    Data from a survey of 4-H Club leaders in Saskatchewan, Canada, were used to determine the effect of attendance at leadership training events on leaders' decisions to re-enroll or discontinue. It was found that involvement in 4-H activities, supported by leadership training, increased leaders' satisfaction and likelihood of re-enrolling. (MF)

  17. Strengthening 4-H Program Communication through Technology

    ERIC Educational Resources Information Center

    Robideau, Kari; Santl, Karyn

    2011-01-01

    Advances in technology are transforming how youth and parents interact with programs. The Strengthening 4-H Communication through Technology project was implemented in eight county 4-H programs in Northwest Minnesota. This article outlines the intentional process used to effectively implement technology in program planning. The project includes:…

  18. Community Development: A 4-H Intern Report.

    ERIC Educational Resources Information Center

    Scheneman, C. Stephen

    State progress reports on the 4-H/Community Development program, a 1973 nationwide Federally sponsored program facilitating youth in community decision-making processes, indicate that the program appears to be evolving into a viable and integral part of the total 4-H program. Although the report describes unique program features of various States,…

  19. Relationships between 4-H Volunteer Leader Competencies and Skills Youth Learn in 4-H Programs

    ERIC Educational Resources Information Center

    Radhakrishna, Rama; Ewing, John C.

    2011-01-01

    This article examined the relationships between 4-H volunteer leader competencies and skills youth learn in 4-H. Using a descriptive-correlational research, the study reported found significant relationships between leadership competencies and skills youth learn in 4-H. Regression analysis revealed that two variables--skills and…

  20. Caffeine and performance in clay target shooting.

    PubMed

    Share, Bianca; Sanders, Nick; Kemp, Justin

    2009-04-01

    Controversy surrounds the influence that caffeine has on accuracy and cognitive performance in precision activities such as shooting and archery. The aim of this study was to assess the effects of two doses of caffeine on shooting performance, reaction time, and target tracking times in the sport of clay target shooting. A randomized, double-blind, placebo-controlled design was undertaken by seven elite male shooters from the double-trap discipline. Three intervention trials (2 mg caffeine . kg(-1) body mass (BM); 4 mg caffeine . kg(-1) BM; placebo) were undertaken, in which shooters completed four rounds per trial of 50 targets per round. Performance accuracy (score) and digital video footage (for determination of reaction time and target tracking times) were gathered during competition. Data were analysed using repeated-measures analysis of variance. No differences in shooting accuracy, reaction time or target tracking times among the three intervention trials or across the four rounds within each intervention were observed (P > 0.05). The results indicate that ingestion of < or =4 mg caffeine . kg(-1) BM does not provide performance benefits to elite performers of clay target shooting in the double-trap discipline.

  1. Separates. 4-H Textile Science Advanced Project.

    ERIC Educational Resources Information Center

    Scholl, Jan F.

    This booklet, which was developed for use by 4-H club members in Pennsylvania, contains the information required to sew a two-piece nontailored outfit and/or a one-or two-piece dress. The following are among the topics covered: the difference between a fiber and a fabric; properties of different fibers and fabrics; common jacket, neckline, sleeve,…

  2. 4-H Textile Science Textile Arts Projects.

    ERIC Educational Resources Information Center

    Scholl, Jan

    This packet contains three 4-H textile arts projects for students in the textile sciences area. The projects cover weaving, knitting, and crocheting. Each project provides an overview of what the student will learn, what materials are needed, and suggested projects for the area. Projects can be adapted for beginning, intermediate, or advanced…

  3. 4-H Science Inquiry Video Series

    ERIC Educational Resources Information Center

    Green, Jeremy W.; Black, Lynette; Willis, Patrick

    2013-01-01

    Studies support science inquiry as a positive method and approach for 4-H professionals and volunteers to use for teaching science-based practices to youth. The development of a science inquiry video series has yielded positive results as it relates to youth development education and science. The video series highlights how to conduct science-rich…

  4. Effectiveness of the 4-H Program as Perceived by Parents of 4-H Participants

    ERIC Educational Resources Information Center

    Radhakrishna, Rama; Foley, Caitlin; Ingram, Patreese; Ewing, John C.

    2013-01-01

    The study reported here examined the effectiveness of 4-H program as perceived by parents of program participants. Descriptive-correlational design was employed, with data collected using a mail survey. Parents perceived 4-H as an effective organization in teaching life skills to youth. Significant relationships were found between parents' skills…

  5. National 4-H Common Measures: Initial Evaluation from California 4-H

    ERIC Educational Resources Information Center

    Lewis, Kendra M.; Horrillo, Shannon J.; Widaman, Keith; Worker, Steven M.; Trzesniewski, Kali

    2015-01-01

    Evaluation is a key component to learning about the effectiveness of a program. This article provides descriptive statistics of the newly developed National 4-H Common Measures (science, healthy living, citizenship, and youth development) based on data from 721 California 4-H youth. The measures were evaluated for their reliability and validity of…

  6. Violence and school shootings.

    PubMed

    Flannery, Daniel J; Modzeleski, William; Kretschmar, Jeff M

    2013-01-01

    Multiple-homicide school shootings are rare events, but when they happen they significantly impact individuals, the school and the community. We focus on multiple-homicide incidents and identified mental health issues of shooters. To date, studies of school shootings have concluded that no reliable profile of a shooter exists, so risk should be assessed using comprehensive threat assessment protocols. Existing studies primarily utilize retrospective case histories or media accounts. The field requires more empirical and systematic research on all types of school shootings including single victim incidents, those that result in injury but not death and those that are successfully averted. We discuss current policies and practices related to school shootings and the role of mental health professionals in assessing risk and supporting surviving victims.

  7. Close Quarters Combat Shooting

    DTIC Science & Technology

    2010-04-14

    1994.at the Palm Beach Community College Criminal Justice Institute ofLakeworth, Florida to the more dynamic force-on-force, realistic scenario...Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington, DC...Shooting is the Superior Method for Close Quarters Combat 5b. GRANT NUMBER Shooting" N/A Sc. PROGRAM ELEMENT NUMBER N/A 6. AUTHOR( S ) Sd. PROJECT

  8. VIBRATIONALLY EXCITED C{sub 4}H

    SciTech Connect

    Cooksy, Andrew L.; Gottlieb, C. A.; Thaddeus, P.; Patel, Nimesh A.; Young, Ken H.; McCarthy, M. C.; Killian, T. C.

    2015-02-01

    Rotational spectra in four new excited vibrational levels of the linear carbon chain radical C{sub 4}H were observed in the millimeter band between 69 and 364 GHz in a low pressure glow discharge, and two of these were observed in a supersonic molecular beam between 19 and 38 GHz. All have rotational constants within 0.4% of the X{sup 2}Σ{sup +} ground vibrational state of C{sub 4}H and were assigned to new bending vibrational levels, two each with {sup 2}Σ and {sup 2}Π vibrational symmetry. The new levels are tentatively assigned to the 1ν{sub 6} and 1ν{sub 5} bending vibrational modes (both with {sup 2}Π symmetry), and the 1ν{sub 6}+1ν{sub 7} and 1ν{sub 5}+1ν{sub 6} combination levels ({sup 2}Σ symmetry) on the basis of the derived spectroscopic constants, relative intensities in our discharge source, and published laser spectroscopic and quantum calculations. Prior spectroscopic constants in the 1ν{sub 7} and 2ν{sub 7} levels were refined. Also presented are interferometric maps of the ground state and the 1ν{sub 7} level obtained with the Submillimeter Array (SMA) near 257 GHz which show that C{sub 4}H is present near the central star in IRC+10216. We found no evidence with the SMA for the new vibrationally excited levels of C{sub 4}H at a peak flux density averaged over a 3{sup ′′} synthesized beam of ⩾0.15 Jy/beam in the 294–296 and 304–306 GHz range, but it is anticipated that rotational lines in the new levels might be observed in IRC+10216 when ALMA attains its full design capability.

  9. Sports Physicals

    MedlinePlus

    ... season. What Is a Sports Physical? In the sports medicine field, the sports physical exam is known as ... to consider possible conditions you may have. Most sports medicine doctors believe the medical history is the most ...

  10. Learnings and Recommendations to Advance 4-H Science Readiness

    ERIC Educational Resources Information Center

    Schmitt-McQuitty, Lynn; Carlos, Ramona; Smith, Martin H.

    2014-01-01

    The case study investigation reported here assessed California 4-H professionals' understanding of the essential components of effective 4-H Science programming as established by the National 4-H Science Mission Mandate. Using the 4-H Science Checklist as the basis for defining 4-H Science Readiness, academic and program staff were surveyed and…

  11. Point and Shoot Astronomy

    NASA Astrophysics Data System (ADS)

    Hoot, John E.

    2011-05-01

    A new generation of point and shoot digital cameras, when combined with open source firmware enhancements can operate as astrographs. This paper explores the research and astro-photographic opportunities and capabilities offered by this pairing of mass production optics and open source functional extensions that retail for as little as $200.

  12. School Shootings Stun Reservation

    ERIC Educational Resources Information Center

    Borja, Rhea R.; Cavanagh, Sean

    2005-01-01

    This article deals with the impact brought by the school shootings at Red Lake Indian Reservation in Minnesota to the school community. A deeply troubled 16-year-old student shot and killed seven other people and himself at a high school. The nation's deadliest school attack since the 1999 slayings at Colorado's suburban Columbine High School took…

  13. Minnesota 4-H Science of Agriculture Challenge: Infusing Agricultural Science and Engineering Concepts into 4-H Youth Development

    ERIC Educational Resources Information Center

    Rice, Joshua E.; Rugg, Bradley; Davis, Sharon

    2016-01-01

    Youth involved in 4-H projects have been engaged in science-related endeavors for years. Since 2006, 4-H has invested considerable resources in the advancement of science learning. The new Minnesota 4-H Science of Agriculture Challenge program challenges 4-H youth to work together to identify agriculture-related issues in their communities and to…

  14. Diversity Inclusion in 4-H Youth Programs: Examining the Perceptions among West Virginia 4-H Youth Professionals

    ERIC Educational Resources Information Center

    LaVergne, Douglas D.

    2013-01-01

    The study reported here sought to examine the perceptions of 4-H youth professionals towards diversity inclusion in 4-H youth programs. A majority of professionals positively reported that there are benefits for youth of color and youth with disabilities in 4-H youth programs. Respondents indicated that the lack of information about 4-H youth…

  15. Curtiss JN-4H Towing Model Wing

    NASA Technical Reports Server (NTRS)

    1921-01-01

    In 1919 the NACA Langley laboratory received its first three research aircraft which were Curtiss JN-4Hs borrowed from the US Army Air Service at Langley Field. One of the first research projects of the laboratory initiated that year was a flight investigation of the lift and drag characteristics of the JN-4H. One of the objectives of the flight tests was to obtain data for correlation with wind-tunnel test results measured at MIT and to aid in the derivation of techniques for extrapolation of model results to full-scale conditions. In a pioneering aeronautical effort in 1920, pressure orifices were installed in the horizontal tail of one of the Jennies and connected to glass manometers for pressure measurements that could be photographed in flight. The NACA also used the aircraft in some of the earliest experiments on maneuverability in 1921. In addition to serving as test subjects, the aircraft were used for measurements of aerodynamic behavior of aircraft components. In this photograph made in 1921, one of the JN- 4Hs is towing a model of an aircraft wing to obtain lift and drag information for comparison to tunnel results. All three Jenny aircraft departed Langley in 1923. Reference: 'Flying the Frontiers: NACA and NASA Experimental Aircraft' by Arthur Pearcy. Naval Institute Press, 1993. ISBN 1-55750-258-7

  16. Sports physical

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000673.htm Sports physical To use the sharing features on this ... or routine checkups. Why do you Need a Sports Physical? The sports physical is done to: Find ...

  17. Shooting Star Experiment

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Shooting Star Experiment (SSE) is designed to develop and demonstrate the technology required to focus the sun's energy and use the energy for inexpensive space Propulsion Research. Pictured is an engineering model (Pathfinder III) of the Shooting Star Experiment (SSE). This model was used to test and characterize the motion and deformation of the structure caused by thermal effects. In this photograph, alignment targets are being placed on the engineering model so that a theodolite (alignment telescope) could be used to accurately measure the deformation and deflections of the engineering model under extreme conditions, such as the coldness of deep space and the hotness of the sun as well as vacuum. This thermal vacuum test was performed at the X-Ray Calibration Facility because of the size of the test article and the capabilities of the facility to simulate in-orbit conditions

  18. Ship and Shoot

    NASA Technical Reports Server (NTRS)

    Woods, Ron

    2012-01-01

    Ron Woods shared incredibly valuable insights gained during his 28 years at the Kennedy Space Center (KSC) packaging Flight Crew Equipment for shuttle and ISS missions. In particular, Woods shared anecdotes and photos from various processing events. The moral of these stories and the main focus of this discussion were the additional processing efforts and effects related to a "ship-and-shoot" philosophy toward flight hardware.

  19. The Level of Vision Necessary for Competitive Performance in Rifle Shooting: Setting the Standards for Paralympic Shooting with Vision Impairment

    PubMed Central

    Allen, Peter M.; Latham, Keziah; Mann, David L.; Ravensbergen, Rianne H. J. C.; Myint, Joy

    2016-01-01

    The aim of this study was to investigate the level of vision impairment (VI) that would reduce performance in shooting; to guide development of entry criteria to visually impaired (VI) shooting. Nineteen international-level shooters without VI took part in the study. Participants shot an air rifle, while standing, toward a regulation target placed at the end of a 10 m shooting range. Cambridge simulation glasses were used to simulate six different levels of VI. Visual acuity (VA) and contrast sensitivity (CS) were assessed along with shooting performance in each of seven conditions of simulated impairment and compared to that with habitual vision. Shooting performance was evaluated by calculating each individual’s average score in every level of simulated VI and normalizing this score by expressing it as a percentage of the baseline performance achieved with habitual vision. Receiver Operating Characteristic curves were constructed to evaluate the ability of different VA and CS cut-off criteria to appropriately classify these athletes as achieving ‘expected’ or ‘below expected’ shooting results based on their performance with different levels of VA and CS. Shooting performance remained relatively unaffected by mild decreases in VA and CS, but quickly deteriorated with more moderate losses. The ability of visual function measurements to classify shooting performance was good, with 78% of performances appropriately classified using a cut-off of 0.53 logMAR and 74% appropriately classified using a cut-off of 0.83 logCS. The current inclusion criteria for VI shooting (1.0 logMAR) is conservative, maximizing the chance of including only those with an impairment that does impact performance, but potentially excluding some who do have a genuine impairment in the sport. A lower level of impairment would include more athletes who do have a genuine impairment but would potentially include those who do not actually have an impairment that impacts performance in the

  20. The Level of Vision Necessary for Competitive Performance in Rifle Shooting: Setting the Standards for Paralympic Shooting with Vision Impairment.

    PubMed

    Allen, Peter M; Latham, Keziah; Mann, David L; Ravensbergen, Rianne H J C; Myint, Joy

    2016-01-01

    The aim of this study was to investigate the level of vision impairment (VI) that would reduce performance in shooting; to guide development of entry criteria to visually impaired (VI) shooting. Nineteen international-level shooters without VI took part in the study. Participants shot an air rifle, while standing, toward a regulation target placed at the end of a 10 m shooting range. Cambridge simulation glasses were used to simulate six different levels of VI. Visual acuity (VA) and contrast sensitivity (CS) were assessed along with shooting performance in each of seven conditions of simulated impairment and compared to that with habitual vision. Shooting performance was evaluated by calculating each individual's average score in every level of simulated VI and normalizing this score by expressing it as a percentage of the baseline performance achieved with habitual vision. Receiver Operating Characteristic curves were constructed to evaluate the ability of different VA and CS cut-off criteria to appropriately classify these athletes as achieving 'expected' or 'below expected' shooting results based on their performance with different levels of VA and CS. Shooting performance remained relatively unaffected by mild decreases in VA and CS, but quickly deteriorated with more moderate losses. The ability of visual function measurements to classify shooting performance was good, with 78% of performances appropriately classified using a cut-off of 0.53 logMAR and 74% appropriately classified using a cut-off of 0.83 logCS. The current inclusion criteria for VI shooting (1.0 logMAR) is conservative, maximizing the chance of including only those with an impairment that does impact performance, but potentially excluding some who do have a genuine impairment in the sport. A lower level of impairment would include more athletes who do have a genuine impairment but would potentially include those who do not actually have an impairment that impacts performance in the sport. An

  1. The Big E (Energy). 4-H Energy Project. 4-H Member's E-Book, Unit 1.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This activity and record book is designed for unit 1 (ages 9-11) of the Nebraska 4-H Energy Project. In this project, members are required to: (1) use energy wisely by closing doors and turning off lights; (2) inspecting homes for energy use at least once; (3) judging the best use of lighting in a home; (4) sharing ideas about energy use in a…

  2. Sport-specific balance.

    PubMed

    Zemková, Erika

    2014-05-01

    This review includes the latest findings based on experimental studies addressing sport-specific balance, an area of research that has grown dramatically in recent years. The main objectives of this work were to investigate the postural sway response to different forms of exercise under laboratory and sport-specific conditions, to examine how this effect can vary with expertise, and to provide examples of the association of impaired balance with sport performance and/or increasing risk of injury. In doing so, sports where body balance is one of the limiting factors of performance were analyzed. While there are no significant differences in postural stability between athletes of different specializations and physically active individuals during standing in a standard upright position (e.g., bipedal stance), they have a better ability to maintain balance in specific conditions (e.g., while standing on a narrow area of support). Differences in magnitude of balance impairment after specific exercises (rebound jumps, repeated rotations, etc.) and mainly in speed of its readjustment to baseline are also observed. Besides some evidence on an association of greater postural sway with the increasing risk of injuries, there are many myths related to the negative influence of impaired balance on sport performance. Though this may be true for shooting or archery, findings have shown that in many other sports, highly skilled athletes are able to perform successfully in spite of increased postural sway. These findings may contribute to better understanding of the postural control system under various performance requirements. It may provide useful knowledge for designing training programs for specific sports.

  3. Using Digital Classrooms to Conduct 4-H Club Meetings

    ERIC Educational Resources Information Center

    West, Patricia; Fuhrman, Nicholas E.; Morgan, A. Christian; Duncan, Dennis W.

    2012-01-01

    Using computer technology and digital classrooms to conduct 4-H Club meetings is an efficient way to continue delivering quality 4-H programming during times of limited resources and staff. Nineteen Junior and Senior 4-H'ers participated in seven digital classroom workshops using the Wimba Classroom application. These digital classroom sessions…

  4. Hamsters?! What Does 4-H Stand for, Anyway?

    ERIC Educational Resources Information Center

    Grundeen, Brenda

    This paper briefly traces the history of 4-H youth development programs, explains what youth development is, and shows how the experiential learning model is used in 4-H. Begun over 75 years ago as a means of extending the learning of the land-grant university to rural youth, 4-H is part of the Cooperative Extension Service. The curriculum…

  5. The 4-H Club Meeting: An Essential Youth Development Strategy

    ERIC Educational Resources Information Center

    Cassels, Alicia; Post, Liz; Nestor, Patrick I.

    2015-01-01

    The club meeting has served as a key delivery method for 4-H programming across the United States throughout its history. A survey of WV 4-H community club members reinforces the body of evidence that the 4-H club meeting is an effective vehicle for delivering positive youth learning opportunities within the umbrella of the Essential Elements of…

  6. Factors Affecting Teen Involvement in Pennsylvania 4-H Programming

    ERIC Educational Resources Information Center

    Gill, Bart E.; Ewing, John C.; Bruce, Jacklyn A.

    2010-01-01

    The study reported here determined the factors that affect teen involvement in 4-H programming. The design of the study was descriptive and correlational in nature. Using a purposive sampling procedure, a survey questionnaire was distributed to all (N=214) 4-H members attending the 4-H State Leadership Conference. The major findings of the study…

  7. The relationship between visual function and performance in rifle shooting for athletes with vision impairment

    PubMed Central

    Myint, Joy; Latham, Keziah; Mann, David; Gomersall, Phil; Wilkins, Arnold J; Allen, Peter M

    2016-01-01

    Background Paralympic sports provide opportunities for those who have an impairment that might otherwise be a barrier to participation in regular sporting competition. Rifle shooting represents an ideal sport for persons with vision impairment (VI) because the direction of the rifle can be guided by auditory information when vision is impaired. However, it is unknown whether those with some remaining vision when shooting with auditory guidance would be at an advantage when compared with those with no vision at all. If this were the case then it would be necessary for those with and without remaining vision to compete in separate classes of competition. Materials and method The associations between shooting performance and 3 measures of visual function thought important for shooting were assessed for 10 elite VI shooters currently classified as VI. A conventional audiogram was also obtained. Results The sample size, though small, included the majority of European VI shooters competing at this level. The relationships between visual functions and performance confirmed that individuals with residual vision had no advantage over those without vision when auditory guidance was available. Auditory function was within normal limits for age, and showed no relationship with performance. Summary The findings suggest that rifle-shooting athletes with VI are able to use auditory information to overcome their impairment and optimise performance. Paralympic competition should be structured in a way that ensures that all shooters who qualify to compete in VI shooting participate within the same class irrespective of their level of VI. PMID:27900160

  8. Shooting Star Experiment

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Shooting Star Experiment (SSE) is designed to develop and demonstrate the technology required to focus the Sun's energy and use the energy for inexpensive space propulsion research. Pictured is an engineering model (Pathfinder III) of SSE and its thermal vacuum test to simulate in-orbit conditions at the X-Ray Calibration Facility at the Marshall Space Flight Center (MSFC). This model was used to test and characterize the motion and deformation of the structure caused by thermal effects. In this photograph, alignment targets are being placed on the engineering model so that a theodolite (alignment telescope) could be used to accurately measure the deformation and deflection of the engineering model under extreme condition, such as the coldness of deep space and the hotness of the Sun, as well as vacuum.

  9. Shooting and Hunting: Instructor's Guide.

    ERIC Educational Resources Information Center

    Smith, Julian W., Comp.

    The shooting and hunting manual, part of a series of books and pamphlets on outdoor education, explains shooting skills, hunting, and proper gun handling on the range and in the field. This manual should be supplemented and enriched by available references, facilities, and resources. It may be included in the community's educational and…

  10. A School Shooting Plot Foiled

    ERIC Educational Resources Information Center

    Swezey, James A.; Thorp, Kimberly A.

    2010-01-01

    Dinkes, Cataldi, and Lin-Kelly (2007) claims that 78% of public schools reported one or more violent incidents during the 2005/2006 school year. School shootings are a rare but real threat on school campuses. Shootings at private schools are even less frequent with only a few recorded examples in the United States. This case study examines how a…

  11. Strigolactone inhibition of shoot branching.

    PubMed

    Gomez-Roldan, Victoria; Fermas, Soraya; Brewer, Philip B; Puech-Pagès, Virginie; Dun, Elizabeth A; Pillot, Jean-Paul; Letisse, Fabien; Matusova, Radoslava; Danoun, Saida; Portais, Jean-Charles; Bouwmeester, Harro; Bécard, Guillaume; Beveridge, Christine A; Rameau, Catherine; Rochange, Soizic F

    2008-09-11

    A carotenoid-derived hormonal signal that inhibits shoot branching in plants has long escaped identification. Strigolactones are compounds thought to be derived from carotenoids and are known to trigger the germination of parasitic plant seeds and stimulate symbiotic fungi. Here we present evidence that carotenoid cleavage dioxygenase 8 shoot branching mutants of pea are strigolactone deficient and that strigolactone application restores the wild-type branching phenotype to ccd8 mutants. Moreover, we show that other branching mutants previously characterized as lacking a response to the branching inhibition signal also lack strigolactone response, and are not deficient in strigolactones. These responses are conserved in Arabidopsis. In agreement with the expected properties of the hormonal signal, exogenous strigolactone can be transported in shoots and act at low concentrations. We suggest that endogenous strigolactones or related compounds inhibit shoot branching in plants. Furthermore, ccd8 mutants demonstrate the diverse effects of strigolactones in shoot branching, mycorrhizal symbiosis and parasitic weed interaction.

  12. Unexpected Stability of Al4H6: a Borane Analog?

    NASA Astrophysics Data System (ADS)

    Xi, Li; Grubisic, Andrej; Stokes, Sarah; Gantefor, Gerd; Bowen, Kit; Boggavarapu, Kiran; Willis, Mary; Jena, Puru; Burgert, Ralph; Schnockel, Hans; Cordes, James

    2007-03-01

    While boron has many hydrides, aluminum has been thought to exhibit relatively few. A combined anion photoelectron and density functional theory computational study of the Al4H6^- anion, and its corresponding neutral, Al4H6, showed that Al4H6 can be understood in terms of the Wade-Mingos rules for electron counting, suggesting that it may be a borane analog. The data support an Al4H6 structure with a distorted tetrahedral aluminum atom framework, four terminal Al-H bonds, and two sets of counter-positioned Al-H-Al bridging bonds. The large HOMO-LUMO gap found for Al4H6 together with its exceptionally high heat of combustion further suggests that Al4H6 may be an important energetic material, if it can be prepared in bulk. This report announces the opening of a new chapter in aluminum-hydrogen chemistry.

  13. Sports Supplements

    MedlinePlus

    ... may affect kidney function. The American College of Sports Medicine recommends that people younger than 18 years old ... help you, talk to your doctor or a sports medicine specialist. The doc will be able to offer ...

  14. Sports Injuries

    MedlinePlus

    ... sometimes you can injure yourself when you play sports or exercise. Accidents, poor training practices, or improper ... can also lead to injuries. The most common sports injuries are Sprains and strains Knee injuries Swollen ...

  15. Sport Biomechanist

    ERIC Educational Resources Information Center

    Sullivan, Megan

    2005-01-01

    If you are an athlete or sports enthusiast, you know that every second counts. To find that 1-2% improvement that can make the difference between 1st and 5th place, sport biomechanists use science to investigate sports techniques and equipment, seeking ways to improve athlete performance and reduce injury risk. In essence, they want athletes to…

  16. Sports Supplements

    MedlinePlus

    ... for Parents for Kids for Teens Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q& ... Sports Supplements? How Some Common Supplements Affect the Body Will Supplements ... improving your sports performance is probably on your mind. Lots of people wonder if taking sports supplements ...

  17. A Cool Sport Full of Physics

    ERIC Educational Resources Information Center

    Hache, Alain

    2008-01-01

    Of all sports, ice hockey is possibly the one with the widest array of physics elements in it. The game provides many examples that can bring physics to life in the classroom. Ice hockey (or just "hockey" as many Canadians would say) sees athletes sliding on ice at high speeds and in various ways, shooting and slapping pucks, and…

  18. The Oneida County 4-H Conservation Field Days Conflict.

    ERIC Educational Resources Information Center

    Brown, Stephen C.; Vonhof, Sarah; Kelley, Alicia

    2003-01-01

    Examines the various perspectives held by the three major organizations involved (an environmental citizens group, a local sportsmen's club, and the cooperative extension service) regarding a conflict over a 4-H program involving hunting and wildlife management. Discusses why the 4-H program's attempt to build consensus among the organizations was…

  19. Sewing Skills Progress Chart. 4-H Textile Science.

    ERIC Educational Resources Information Center

    Scholl, Jan F.

    This document, which was developed for use by Pennsylvania 4-H Club leaders and members, is a chart that can be used to help club members determine and document those sewing skills they already have and those they need to learn as they complete one or more 4-H Club sewing projects. The document begins with a note to club leaders and parents that…

  20. Camping with a Purpose...A 4-H Handbook.

    ERIC Educational Resources Information Center

    Heller, John H.; And Others

    The 4-H handbook focuses on factors to consider and things to be done when developing a camping program. Since the emphasis, structure, and administration of 4-H camping varies, the booklet is flexible enough to be adapted to different state, district, and county situations. Major topics are camping's importance to extension education,…

  1. Council of Presidents: A Multifaceted Idea for 4-H

    ERIC Educational Resources Information Center

    Torretta, Alayne

    2015-01-01

    Communication between 4-H professionals and the youth they work with is an important part of a successful 4-H program. By creating a Council of Presidents comprised of officers of all the clubs in your county, you can increase communication while assuring your program addresses all four essential elements. The Council is also as a vehicle for…

  2. Stabilization of 4H hexagonal phase in gold nanoribbons

    PubMed Central

    Fan, Zhanxi; Bosman, Michel; Huang, Xiao; Huang, Ding; Yu, Yi; Ong, Khuong P.; Akimov, Yuriy A.; Wu, Lin; Li, Bing; Wu, Jumiati; Huang, Ying; Liu, Qing; Eng Png, Ching; Lip Gan, Chee; Yang, Peidong; Zhang, Hua

    2015-01-01

    Gold, silver, platinum and palladium typically crystallize with the face-centred cubic structure. Here we report the high-yield solution synthesis of gold nanoribbons in the 4H hexagonal polytype, a previously unreported metastable phase of gold. These gold nanoribbons undergo a phase transition from the original 4H hexagonal to face-centred cubic structure on ligand exchange under ambient conditions. Using monochromated electron energy-loss spectroscopy, the strong infrared plasmon absorption of single 4H gold nanoribbons is observed. Furthermore, the 4H hexagonal phases of silver, palladium and platinum can be readily stabilized through direct epitaxial growth of these metals on the 4H gold nanoribbon surface. Our findings may open up new strategies for the crystal phase-controlled synthesis of advanced noble metal nanomaterials. PMID:26216712

  3. [SPORT MEDICINE].

    PubMed

    Constantini, Naama; Mann, Gideon

    2016-06-01

    Sports Medicine is a relatively new subject in medicine and includes a variety of medical and paramedical fields. Although sports medicine is mistakenly thought to be mainly for sports professionals/athletes, it actually encompasses the entire population, including the active and non-active healthy populations, as well as the sick. Sports medicine also engages amateur sportsmen and strives to promote physical activity and quality of life in the general population. Hence, the field involves all ages from childhood to old age, aiming to preserve and support every person at every age. Sports medicine, which started developing in the 19th century, is today a specialty, primary or secondary, in many countries, while in others it is a fellowship or under the jurisdiction of local or sports authorities. In Israel, the field exists since the 1950's and is advanced. The Sports Medicine Society founded a 3-year course of continued education in sport medicine as part of the Tel-Aviv University Faculty of Medicine. Later on, a fellowship in general Sports Medicine and in Orthopedic Sports Medicine were developed within the Israel Medical Association. A year ago, Israel formally became a member of the global "Exercise is Medicine" foundation, and under this title promotes education for health care providers on exercise prescription. The understanding of the importance of physical activity and fitness as part of a healthy lifestyle is increasing in Israel, as well as the number of amateur athletes, and the profession of sports medicine takes a big part in this process.

  4. [Sport medicine].

    PubMed

    Epstein, Yoram

    2012-02-01

    It is only since the late 20th century that Sport and Exercise Medicine has emerged as a distinct entity in health care. In Israel, sports medicine is regulated by a State Law and a sport physician is certified after graduating a structured program. In the past, sports medicine was related to the diagnosis and treatment of injuries encountered by top athletes. In recent years, the scope of sport medicine has broadened to reflect the awareness of modern society of the dangers of physical inactivity. In this perspective the American College of Sport Medicine (ACSM) recently launched a program--"Exercise is Medicine", to promote physical activity in order to improve health and well-being and prevention of diseases through physical activity prescriptions. This program is from doctors and healthcare providers, adjusted to the patient or trainee. The sport physician does not replace a medical specialist, but having a thorough understanding about the etiology of a sport-related injury enables him to better focus on treatment and prevention. Therefore, Team Physicians in Elite Sport often play a role regarding not only the medical care of athletes, but also in the physiological monitoring of the athlete and correcting aberrations, to achieve peak physical performance. The broad spectrum of issues in sport and exercise medicine cannot be completely covered in one issue of the Journal. Therefore, the few reports that are presented to enhance interest and understanding in the broad spectrum of issues in sports and exercise medicine are only the tip of the iceberg.

  5. Neurophysiological responses to gun-shooting errors.

    PubMed

    Xu, Xiaowen; Inzlicht, Michael

    2015-03-01

    The present study investigated the neural responses to errors in a shooting game - and how these neural responses may relate to behavioral performance - by examining the ERP components related to error detection (error-related negativity; ERN) and error awareness (error-related positivity; Pe). The participants completed a Shooter go/no-go task, which required them to shoot at armed targets using a gaming gun, and avoid shooting innocent non-targets. The amplitude of the ERN and Pe was greater for shooting errors than correct shooting responses. The ERN and Pe amplitudes elicited by incorrect shooting appeared to have good internal reliability. The ERN and Pe amplitudes elicited by shooting behaviors also predicted better behavioral sensitivity towards shoot/don't-shoot stimuli. These results suggest that it is possible to obtain online brain response measures to shooting responses and that neural responses to shooting are predictive of behavioral responses.

  6. Texas 4-H Agents' Perceptions of Selected Competencies in the 4-H Professional Research, Knowledge, and Competencies Model

    ERIC Educational Resources Information Center

    Harder, Amy; Wingenbach, Gary J.

    2008-01-01

    There are many competencies necessary for success as a 4-H agent. The 4-H Professional Research, Knowledge, and Competencies (PRKC) Model organizes competencies into six domains: (a) Youth Development, (b) Youth Program Development, (c) Volunteerism, (d) Partnerships, (e) Organizational Systems, and (f) Equity, Access and Opportunity (National 4-H…

  7. A Real Shooting Star

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of A Real Shooting Star

    This artist's animation illustrates a star flying through our galaxy at supersonic speeds, leaving a 13-light-year-long trail of glowing material in its wake. The star, named Mira (pronounced my-rah) after the latin word for 'wonderful,' sheds material that will be recycled into new stars, planets and possibly even life. NASA's Galaxy Evolution Explorer discovered the long trail of material behind Mira during its survey of the entire sky in ultraviolet light.

    The animation begins by showing a close-up of Mira -- a red-giant star near the end of its life. Red giants are red in color and extremely bloated; for example, if a red giant were to replace our sun, it would engulf everything out to the orbit of Mars. They constantly blow off gas and dust in the form of stellar winds, supplying the galaxy with molecules, such as oxygen and carbon, that will make their way into new solar systems. Our sun will mature into a red giant in about 5 billion years.

    As the animation pulls out, we can see the enormous trail of material deposited behind Mira as it hurls along between the stars. Like a boat traveling through water, a bow shock, or build up of gas, forms ahead of the star in the direction of its motion. Gas in the bow shock is heated and then mixes with the cool hydrogen gas in the wind that is blowing off Mira. This heated hydrogen gas then flows around behind the star, forming a turbulent wake.

    Why does the trailing hydrogen gas glow in ultraviolet light? When it is heated, it transitions into a higher-energy state, which then loses energy by emitting ultraviolet light - a process known as fluorescence.

    Finally, the artist's rendering gives way to the actual ultraviolet image taken by the Galaxy Evolution Explorer

    Mira is located 350 light-years from Earth in the constellation Cetus, otherwise known as the whale. Coincidentally, Mira

  8. Sports dentistry.

    PubMed

    Saini, Rajiv

    2011-07-01

    Sports dentistry is one of the most recent and upcoming field in dentistry. It mainly includes the prevention and management of athletics-related orofacial injuries and associated oral diseases. The sports or team dentist assists athletes in the prevention, treatment, and diagnosis of oral injuries. The most significant aspect in preventing sports-related orofacial injuries is wearing basic protective devices such as properly-fitting helmets, face masks and/or mouth guards. Dental injuries are the most common type of orofacial injury sustained during participation in sports. Many athletes are not aware of the health implications of a traumatic injury to the mouth or of the potential for incurring severe head and orofacial injuries while playing. The dentist can play an imperative role in informing athletes, coaches and patients about the importance of preventing orofacial injuries in sports. The aim of this paper is to increase professional awareness and interest for orientation toward sports dentistry.

  9. Sodium diffusion in 4H-SiC

    SciTech Connect

    Linnarsson, M. K. Hallén, A.

    2014-09-01

    Sodium diffusion has been studied in p-type 4H-SiC. Heat treatments have been performed from 1200 °C to 1800 °C for 1 min to 4 h. Secondary ion mass spectrometry has been used to measure the sodium distribution. We show that sodium has a considerable mobility at 1200 °C in p-type 4H-SiC. On the other hand for sodium atoms trapped at suitable sites the mobility is limited up to 1800 °C. Trap limited diffusion kinetics is suggested and an effective diffusivity has been extracted with an activation energy of 4 eV for sodium diffusion in p-type 4H-SiC.

  10. Sports Physicals

    MedlinePlus

    ... stronger athlete. previous continue When & Where Should I Go for a Sports Physical? Some people go to their own doctor for a sports physical; ... one at school. During school physicals, you may go to half a dozen or so "stations" set ...

  11. Sport Management.

    ERIC Educational Resources Information Center

    Parkhouse, Bonnie L., Ed.; And Others

    1984-01-01

    Traditional teaching and coaching positions have become scarce but the expanding field of sport management has created its own job market, demanding new skills and preparation. Three articles are offered that explore different aspects and possibilities for a sport management career. (DF)

  12. Sports Nutrition.

    ERIC Educational Resources Information Center

    Missouri State Dept. of Health, Jefferson City.

    This guide deals with various aspects of sports and nutrition. Twelve chapters are included: (1) "Sports and Nutrition"; (2) "Eat to Compete"; (3) "Fit Folks Need Fit Food"; (4) "The Food Guide Pyramid"; (5) "Fat Finder's Guide"; (6) "Pre- and Post-Event Meals"; (7) "Tips for the…

  13. School Shootings and Critical Pedagogy

    ERIC Educational Resources Information Center

    Schiller, Juliet

    2013-01-01

    What has been left out of studying school violence and shootings is a comprehensive look at the culture that creates violence and the lack of support for those deemed "different" in an educational setting that promotes and rewards competition. If parents, teachers, and other adults associated with children were teaching the values of…

  14. School Shootings in Policy Spotlight

    ERIC Educational Resources Information Center

    Maxwell, Lesli A.

    2006-01-01

    The three school shootings that left a principal and six students dead in less than a week have sparked a barrage of pledges from national and state political leaders to tighten campus security. School safety experts urged caution against overreacting to the horrific, but rare, incidents in rural schools in Colorado, Pennsylvania, and Wisconsin.…

  15. Shootings Revive Debates on Security

    ERIC Educational Resources Information Center

    Shah, Nirvi

    2013-01-01

    By nearly all accounts, the staff and students at Sandy Hook Elementary School did everything right on Dec. 14--and with the security measures they took before that day--when a young man armed with powerful weapons blasted his way into the school. But the deadliest K-12 school shooting in American history, a day that President Barack Obama has…

  16. Gravitropism of cut shoots is mediated by oxidative processes: A physiological and molecular study

    NASA Astrophysics Data System (ADS)

    Philosoph-Hadas, Sonia; Friedman, Haya; Meir, Shimon

    2012-07-01

    The signal transduction events occurring during shoot gravitropism are mediated through amyloplasts sedimentation, reorientation of actin filaments in the endodermis, and differential changes in level and action of auxin, associated with differential growth leading to shoot curvature. Since increase in reactive oxygen species (ROS) was shown to be associated with growth, we examined the possible use of antioxidants in controlling the gravitropic response, via their interaction with events preceding shoot bending. Reoriented snapdragon (Antirrhinum majus L.) spikes and tomato (Solanum lycopersicum cv. MicroTom) shoots showed a visual upward bending after a lag period of 3 or 5 h, respectively, which was inhibited by the antioxidants N-acetyl-cysteine (NAC) and reduced glutathione (GSH). This suggests the involvement of oxidative reactions in the process. The two antioxidants prevented the sedimentation of amyloplasts to the bottom of the endodermis cells following 0.5-5 h of snapdragon shoot reorientation, suggesting that oxidative reactions are involved already at a very early signal perception stage prior to the visual bending. In addition, a differential distribution in favor of the lower shoot side of various oxidative elements, including H2O2 concentrations and activity of the NADPH-oxidase enzyme, was observed during reorientation of snapdragon spikes. Application of the two antioxidants reduced the levels of these elements and abolished their differential distribution across the shoot. On the other hand, the activity of the antioxidative enzyme, superoxide dismutase (SOD), which was not differentially distributed across the shoot, increased significantly following application of the two antioxidants. The auxin redistribution in reoriented shoots was analyzed using transgenic tomato plants expressing the GUS reporter gene under the Aux/IAA4 promoter (a generous gift of M. Bouzayen, France). GUS response, detected in control shoots 4 h after their reorientation

  17. The Big E (Energy). 4-H Member Guide, Unit 3.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This activity and record book is designed for unit 3 (ages 15-19) of the Nebraska 4-H Energy Project. Aims, energy attitudes to be developed, and instructions are provided for each activity. Activities include: (1) determining ways to reduce energy waste with hot water heaters; (2) making personal choices about using appliances; (3) conducting a…

  18. The Big E (Energy). 4-H Member Guide, Unit 2.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This activity and record book is designed for unit 2 (ages 12-14) of the Nebraska 4-H Energy Project. Aims, energy attitudes to be developed, and instructions are provided for each activity. Activities include: (1) a word search of energy-related words (with definitions provided); (2) determining fuel waste; (3) reading electric/gas meters and…

  19. "Ohio 4-H CARTEENS": Peer Intervention Safety Program.

    ERIC Educational Resources Information Center

    Cropper, Rebecca J.

    1999-01-01

    Ohio 4-H's CARTEENS seeks to reduce juvenile traffic violations in a program designed and presented by teen peer educators with guidance and technical assistance from the state highway patrol. Teens examined court data to determine content, which includes defensive driving, rural road safety, and dealing with peer pressure. (SK)

  20. Minnesota 4-H Youth Program Quality Improvement Model

    ERIC Educational Resources Information Center

    Herman, Margo; Grant, Samantha

    2015-01-01

    The University of Minnesota Extension Center for Youth Development made an organizational decision in 2011 to invest in a system-wide approach to implement youth program quality into the 4-H program using the Youth Program Quality Assessment (YPQA) tool. This article describes the four key components to the Minnesota Youth Program Quality…

  1. Keys To The Kansas Environment. 4-H School Enrichment Program.

    ERIC Educational Resources Information Center

    Kansas State Univ., Manhattan. Extension Service.

    The 4-H Club packet for preschool and elementary school children contains nine "keys", or short learning exercises, designed to enrich science and environmental education both in and out of the classroom. Each "key" includes the purpose of the activity, the intended audience, the best time of the year for the activity,…

  2. Effectiveness of the Indiana 4-H Tractor Program: Alumni Perceptions.

    ERIC Educational Resources Information Center

    Carrabba, James J., Jr.; Talbert, B. Allen; Field, William E.; Tormoehlen, Roger

    2001-01-01

    Responses from Indiana 4-H tractor driving contestants 1982-197 (n=139) showed that 74% were employed on farms; most felt the contests effectively taught tractor safety and made them generally aware of safety. However, many still engaged in risky behaviors such as not wearing seatbelts in tractors with rollover protective structures or allowing…

  3. Implementing and Assessing 4-H Educational Activity Kits for Children

    ERIC Educational Resources Information Center

    Scheer, Scott D.; Yeske, Janine; Zimmer, Bruce

    2011-01-01

    Educational activity kits were developed and implemented through a statewide effort for 4-H Youth Development Extension programs serving 5-8 year-old children. The purpose of the kits was to promote life skills in children and assess the learning environment. Data was collected based on the observations of 577 children across 22 counties. Findings…

  4. South Carolina's Model for Initiating Hispanic 4-H Clubs

    ERIC Educational Resources Information Center

    Lippert, Robert; Rembert, Kellye

    2012-01-01

    Over the past 5 years, through the initiative of several county Extension agents, South Carolina 4-H has established a successful model for bringing Hispanic youth into our program. We have found the most effective method is to initiate contact and establish partnerships with the principals and ESOL instructors in the local schools. Through this…

  5. CONSERVING OUR NATURAL RESOURCES, A 4-H LEADER'S GUIDE.

    ERIC Educational Resources Information Center

    AMICK, W. ROBERT; AND OTHERS

    AN EFFECTIVE 4-H CONSERVATION PROGRAM IS DEVELOPED AROUND THE FOLLOWING BASIC CONCEPTS--(1) MAN IS A PART OF THE NATURAL WORLD, IN WHICH THERE ARE MANY VALUABLE MATERIALS, (2) MAN HAS LEARNED TO USE MANY OF THOSE MATERIALS FOR HUMAN SUSTENANCE AND BETTERMENT, AND (3) MAN'S ECONOMIC, SOCIAL, AND GENERAL WELFARE IS LARGELY DEPENDENT UPON THE MANNER…

  6. New Jersey 4-H Marine Science Project. Leaders Guide.

    ERIC Educational Resources Information Center

    Jesuncosky, Betty Jean, Comp.

    This guide contains a collection of activities which are designed to provide opportunities for 4-H voluteers and youth in New Jersey to get involved in learning about the marine environment. The guide is divided into five sections which deal with habitats, organisms, career exploration, community involvement, and additional marine activities. Each…

  7. A Phenomenological Look at 4-H Volunteer Motives for Service

    ERIC Educational Resources Information Center

    Schrock, Jessalyn; Kelsey, Kathleen D.

    2013-01-01

    Volunteers play a vital role in 4-H programs. Without their service, many programs would not be possible. Understanding volunteer motives provides Extension educators with tools for finding high-quality volunteers. The research reported here used McClelland's (1985) framework for motivation (affiliation, achievement, and power) and…

  8. Textile Science Leader's Guide. 4-H Textile Science.

    ERIC Educational Resources Information Center

    Scholl, Jan

    This instructor's guide provides an overview of 4-H student project modules in the textile sciences area. The guide includes short notes explaining how to use the project modules, a flowchart chart showing how the project areas are sequenced, a synopsis of the design and content of the modules, and some program planning tips. For each of the…

  9. Fashion Revue. 4-H Textile Science Activity Guide.

    ERIC Educational Resources Information Center

    Scholl, Jan

    This publication was developed to help students participating in Fashion Review, a 4-H event in which students model a clothing outfit and accessories and are judged on their modeling ability, their presentation, and how well the clothing and accessory choices complement the students' skin tones, hair color, figure or physique, personality, and…

  10. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  11. Sport Psychology.

    ERIC Educational Resources Information Center

    Krotee, March L.

    1980-01-01

    Sport psychology is defined in terms of human behavior in athletic situations. The psychosocial cross-cultural setting provides a model for studying trait and state psychosocial attributes and suggests issues and concerns for further study. (JMF)

  12. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  13. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 9 2012-10-01 2012-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  14. Training Visual Control in Wheelchair Basketball Shooting

    ERIC Educational Resources Information Center

    Oudejans, Raoul R. D.; Heubers, Sjoerd; Ruitenbeek, Jean-Rene J. A. C.; Janssen, Thomas W. J.

    2012-01-01

    We examined the effects of visual control training on expert wheelchair basketball shooting, a skill more difficult than in regular basketball, as players shoot from a seated position to the same rim height. The training consisted of shooting with a visual constraint that forced participants to use target information as late as possible.…

  15. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 9 2013-10-01 2013-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  16. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 9 2014-10-01 2014-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  17. YA4-H! Youth Advocates for Health: Impact of a 4-H Teens-as-Teachers Program

    ERIC Educational Resources Information Center

    Arnold, Mary E.; Flesch, Jeffrey M.; Ashton, Carolyn; Black, Lynette; Brody, Barbara; Hosty, Maureen; Northway, Shanna

    2016-01-01

    This article reports the results of an evaluation of the YA4-H! Youth Advocates for Health--Teens as Teachers program. Consistent with previous research on the impact of teen teaching, the teens participating in the program gained confidence and skill with regard to teaching younger youths. The program also affected the teens' understanding that…

  18. New Jersey 4-H Goat Extravaganza: Efficiently Meeting the Educational Needs of 4-H Goat Project Members, Volunteers, and Parents

    ERIC Educational Resources Information Center

    Ripberger, Chad

    2014-01-01

    The 4-H Goat Extravaganza maximizes limited resources to help youth and adults develop knowledge and skills in goat care and management. It capitalizes on the talents and interests of volunteers to efficiently combine a goat-themed art show, team presentation contest, quiz bowl, skillathon, and adult workshop into 1 day. This article outlines the…

  19. Water Worlds. 4-H Member's Guide M-5-18; 4-H Leaders Guide L-5-18.

    ERIC Educational Resources Information Center

    Hawkes, Janet E.; And Others

    This pocket folder of materials is designed to provide children aged 9 to 12 with an opportunity to explore and observe aquatic environments. The package includes a 4-H Leader's guide, member's guide, and supplementary materials. The leader's guide contains safety considerations, tips and techniques, and additional activities for getting started…

  20. Litter Control Achievement - Ohio 4-H Club Score Sheet [and] Activity Guides 1 through 7. 4-H Pilot Program 918.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Cooperative Extension Service.

    Seven activity guides, evaluation sheet, and club scoresheet have been prepared for Ohio 4-H clubs' litter education program. Topics of the seven activity guides include: (1) general guidelines and types of activities; (2) little known facts about waste/litter; (3) guidelines for a walking tour; (4) fact sheet (questionnaire) related to garbage;…

  1. Starting and Maintaining a Marine Aquarium: 4-H Members Guide [and] 4-H Member's Project Record Book.

    ERIC Educational Resources Information Center

    Crenshaw, Neil

    The guide and the project record book included in this document are designed for 4-H members who would like to start a salt-water aquarium project. The guide includes the following topics: (1) general requirements for salt-water aquariums; (2) directions for making an aquarium; (3) suggestions for where to locate it; (4) pros and cons of using…

  2. Shoot regeneration and embryogenesis in lily shoot tips cryopreserved by droplet vitrification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shoot regeneration and embryogenesis were, for the first time, achieved directly in shoot tips of Lilium Oriental hybrid ‘Siberia’ following cryopreservation by droplet-vitrification. Shoot tips (2 mm in length) including 2-3 leaf primordia were excised from 4-week-old adventitious shoots directly r...

  3. Multiple pathways regulate shoot branching

    PubMed Central

    Rameau, Catherine; Bertheloot, Jessica; Leduc, Nathalie; Andrieu, Bruno; Foucher, Fabrice; Sakr, Soulaiman

    2015-01-01

    Shoot branching patterns result from the spatio-temporal regulation of axillary bud outgrowth. Numerous endogenous, developmental and environmental factors are integrated at the bud and plant levels to determine numbers of growing shoots. Multiple pathways that converge to common integrators are most probably involved. We propose several pathways involving not only the classical hormones auxin, cytokinins and strigolactones, but also other signals with a strong influence on shoot branching such as gibberellins, sugars or molecular actors of plant phase transition. We also deal with recent findings about the molecular mechanisms and the pathway involved in the response to shade as an example of an environmental signal controlling branching. We propose the TEOSINTE BRANCHED1, CYCLOIDEA, PCF transcription factor TB1/BRC1 and the polar auxin transport stream in the stem as possible integrators of these pathways. We finally discuss how modeling can help to represent this highly dynamic system by articulating knowledges and hypothesis and calculating the phenotype properties they imply. PMID:25628627

  4. Managing Collegiate Sport Clubs.

    ERIC Educational Resources Information Center

    Matthews, David O., Ed.

    This book is written for the administrators of college sport clubs. It is comprised of a collection of articles on the topics of: (1) Sport Club Administration and Organization; (2) Student Development through Sport Clubs; (3) Sport Club Financing and Fund-Raising; (4) Liability Concerns of Sport Clubs; and (5) Sport Club Program Surveys.…

  5. 78 FR 50443 - Notice of Temporary Closure to Target Shooting on Public Lands in Yakima County, WA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... months after publication. FOR FURTHER INFORMATION CONTACT: Linda Coates-Markle, Wenatchee Field Manager... Federal Lands Hunting, Fishing and Shooting Sports Roundtable has been contacted and engaged several times... legal hunting activities consistent with Washington Department of Fish and Wildlife regulations...

  6. A Perfect Fit: 4-H Involvement for Youth with Disabilities. A Leader's Guide.

    ERIC Educational Resources Information Center

    Schnepf, Greg W.; And Others

    This guide for 4-H leaders and volunteers offers information to help integrate youth with disabilities into various 4-H programs. After an introduction, a section on 4-H and mainstreaming reviews the mission of 4-H; considers what 4-H has to offer youth; defines mainstreaming; notes the benefits of mainstreaming; and distinguishes among the terms…

  7. Trust My Face: Cognitive Factors of Head Fakes in Sports

    ERIC Educational Resources Information Center

    Kunde, Wilfried; Skirde, Stefanie; Weigelt, Matthias

    2011-01-01

    In many competitive sports, players try to deceive their opponents about their behavioral intentions by using specific body movements or postures called fakes. For example, fakes are performed in basketball when a player gazes in one direction but passes or shoots the ball in another direction to avert efficient defense actions. The present study…

  8. Sports Ballistics

    NASA Astrophysics Data System (ADS)

    Clanet, Christophe

    2015-01-01

    This review describes and classifies the trajectories of sports projectiles that have spherical symmetry, cylindrical symmetry, or (almost) no symmetry. This classification allows us to discuss the large diversity observed in the paths of spherical balls, the flip properties of shuttlecocks, and the optimal position and stability of ski jumpers.

  9. Sports Marketing.

    ERIC Educational Resources Information Center

    Ohio State Dept. of Education, Columbus. Div. of Career-Technical and Adult Education.

    This document presents the Ohio Integrated Technical and Academic Competency profile for sports marketing. The profile is to serve as the basis for curriculum development in Ohio's secondary, adult, and postsecondary programs. The profile includes a comprehensive listing of 999 specialty key indicators for evaluating mastery of 113 competencies in…

  10. Racquet Sports.

    ERIC Educational Resources Information Center

    Zebas, Carole J., Ed.; Groppel, Jack L., Ed.

    1983-01-01

    In six articles on racquet sports, the origins of the games are traced, methods for teaching skills such as footwork, racquetball strategy, and badminton techniques are discussed, and the biomechanics of the one- and two-handed backhand in tennis are reviewed. Information about paddle tennis is included. (PP)

  11. Sports Wagering

    ERIC Educational Resources Information Center

    Rockey, Donald L., Jr.; King, Chris

    2006-01-01

    This chapter discusses wagering on college athletics and sports wagering by college students and student athletes. Programs implemented by the National Collegiate Athletic Association (NCAA) and other organizations to minimize such behavior are also discussed, and recommendations for practice and research are shared.

  12. Leakage currents in 4H-SiC JBS diodes

    SciTech Connect

    Ivanov, P. A. Grekhov, I. V.; Potapov, A. S.; Kon'kov, O. I.; Il'inskaya, N. D.; Samsonova, T. P.; Korol'kov, O.; Sleptsuk, N.

    2012-03-15

    Leakage currents in high-voltage 4H-SiC diodes, which have an integrated (p-n) Schottky structure (Junction Barrier Schottky, JBS), have been studied using commercial diodes and specially fabricated (based on a commercial epitaxial material) test Schottky diodes with and without the JBS structure. It is shown that (i) the main role in reverse charge transport is played by SiC crystal structure defects, most probably, by threading dislocations (density {approx}10{sup 4} cm{sup -2}), and (ii) the JBS structure, formed by the implantation of boron, partially suppresses the leakage currents (by up to a factor of 10 at optimal separation, 8 {mu}m between local p-type regions).

  13. Extended defects in 4H-silicon carbide homoepitaxial layers

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan

    The purpose of this thesis is to study the structure of extended defects in 4H-SIC homoepitaxial layers, and to identify their nucleation mechanisms. Characteristics of basal plane dislocations in 4H-SiC epilayers were investigated in a comprehensive manner, including their morphologies, Burgers' vectors, positions, and correlation with the extended defects propagating from the substrate. Plan-view transmission x-ray topography was the major characterization technique used in this study. Complementary data was obtained by KOH etching and optical microscopy. Trace of glide was detected on every basal plane dislocation in the entire 3-inch epilayer. In the center area of the epi-wafer, the glide can extend to macroscopic distance and form edge-type dislocations at the epilayer/surface interface. During the motion, dislocation half loop arrays were found to nucleate at the growth front. The magnitude of the resolved shear stress was estimated based on the radius of curvature of the dislocation lines. It surpassed the critical resolved shear stress at the epitaxial growth temperature. The stress was identified to be compressive in the epilayer. Its origin was studied. Nitrogen-doping-difference-induced misfit strain was excluded as the source of the stress. The structures of two morphological defects, 'carrots' and 'arrows', were studied. Cross-section x-ray topography was used to image the structure of carrot defect in whole. The defect was found to nucleate at the epilayer/substrate interface on a threading screw dislocation propagating from the substrate. Its structure was mainly composed of a prismatic stacking fault and a Frank-type basal plane stacking fault. The arrow defect was found to be produced by a spheroid shape inclusion in the volume of the epilayer. Zone axis diffraction pattern under transmission electron microscope identified the nature of the inclusion as 3C-SIC. It was determined to nucleate at the substrate surface contaminations.

  14. Convergent evolution of shoots in land plants: lack of auxin polar transport in moss shoots.

    PubMed

    Fujita, Tomomichi; Sakaguchi, Hisako; Hiwatashi, Yuji; Wagstaff, Steven J; Ito, Motomi; Deguchi, Hironori; Sato, Toshiyuki; Hasebe, Mitsuyasu

    2008-01-01

    The shoot is a repeated structure made up of stems and leaves and is the basic body plan in land plants. Vascular plants form a shoot in the diploid generation, whereas nonvascular plants such as mosses form a shoot in the haploid generation. It is not clear whether all land plants use similar molecular mechanisms in shoot development or how the genetic networks for shoot development evolved. The control of auxin distribution, especially by polar auxin transport, is essential for shoot development in flowering plants. We did not detect polar auxin transport in the gametophytic shoots of several mosses, but did detect it in the sporophytes of mosses without shoot structure. Treatment with auxin transport inhibitors resulted in abnormal embryo development, as in flowering plants, but did not cause any morphological changes in the haploid shoots. We fused the soybean auxin-inducible promoter GH3 with a GUS reporter gene and used it to indirectly detect auxin distribution in the moss Physcomitrella patens. An auxin transport inhibitor NPA did not cause any changes in the putative distribution of auxin in the haploid shoot. These results indicate that polar auxin transport is not involved in haploid shoot development in mosses and that shoots in vascular plants and mosses are most likely regulated differently during development.

  15. Supporting the paralympic athlete: focus on wheeled sports.

    PubMed

    Goosey-Tolfrey, Victoria

    2010-01-01

    The complexity of wheelchair sports provides the scientist with a unique challenge. There are two major components that contribute towards 'wheeled sports' performance: the athlete and the chair. It is the interaction of these two components that enable wheelchair propulsion and the sporting movements required within a given sport. This article will describe three discrete case studies on how sport scientists have worked with Great Britain coaches and practitioners to help optimise training leading to a major competition through evidence base practise. A fourth area will describe on-going work designed to address the optimisation of wheelchair configurations for wheelchair court sports. It will focus on four sports: wheelchair racing, wheelchair tennis, wheelchair basketball and wheelchair rugby. The first topic will discuss the concept of pushing economy and mechanical efficiency of wheelchair propulsion. The second topic will show how technology assists the coaching process. The third topic will illustrate the concept of sports classification, and show how training volume 'in terms of basketball shooting' may need to be individually assigned and finally future research within wheelchair team sports and chair configurations will be examined.

  16. Tragedy and the Meaning of School Shootings

    ERIC Educational Resources Information Center

    Warnick, Bryan R.; Johnson, Benjamin A.; Rocha, Samuel

    2010-01-01

    School shootings are traumatic events that cause a community to question itself, its values, and its educational systems. In this article Bryan Warnick, Benjamin Johnson, and Samuel Rocha explore the meanings of school shootings by examining three recent books on school violence. Topics that grow out of these books include (1) how school shootings…

  17. Lockheed P-80A Shooting Star

    NASA Technical Reports Server (NTRS)

    1946-01-01

    Lockheed P-80A Shooting Star: The Lockheed P-80A Shooting Star was America's first fully operation jet fighter. This all-yellow example arrived at Langley in November 1946. The P-80 was used for air speed calibration and development of a tuned vibration damper.

  18. A shooting approach to suboptimal control

    NASA Technical Reports Server (NTRS)

    Hull, David G.; Sheen, Jyh-Jong

    1991-01-01

    The shooting method is used to solve the suboptimal control problem where the control history is assumed to be piecewise linear. Suboptimal solutions can be obtained without difficulty and can lead to accurate approximate controls and good starting multipliers for the regular shooting method by increasing the number of nodes. Optimal planar launch trajectories are presented for the advanced launch system.

  19. Cryopreservation of in vitro grown shoot tips

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter in Plant Cell Culture, Development and Biotechnology describes student laboratory exercises for cryopreservation of the growing shoot tips of plants in liquid nitrogen. It includes two exercises involving step by step protocols for use with shoot tips. Vitrification (fast freezing) an...

  20. Sports Medicine Today

    ERIC Educational Resources Information Center

    Ryan, Allan J.

    1978-01-01

    Includes a general discussion of sports medicine including exercise and conditioning techniques, prevention of illness and injury, treatment of and rehabilitation after sports injury, and the future of sports medicine. (BB)

  1. Sports cream overdose

    MedlinePlus

    Sports creams are creams or ointments used to treat aches and pains. Sports cream overdose can occur if someone uses this ... Two ingredients in sports creams that can be poisonous are: Menthol Methyl salicylate

  2. Sports Hernia (Athletic Pubalgia)

    MedlinePlus

    .org Sports Hernia (Athletic Pubalgia) Page ( 1 ) A sports hernia is a painful, so tissue injury that occurs in ... groin area. It most o en occurs during sports that require sudden changes of direction or intense ...

  3. Training visual control in wheelchair basketball shooting.

    PubMed

    Oudejans, Raôul R D; Heubers, Sjoerd; Ruitenbeek, Jean-René J A C; Janssen, Thomas W J

    2012-09-01

    We examined the effects of visual control training on expert wheelchair basketball shooting, a skill more difficult than in regular basketball, as players shoot from a seated position to the same rim height. The training consisted of shooting with a visual constraint that forced participants to use target information as late as possible. Participants drove under a large screen that initially blocked the basket. As soon as they saw the basket they shot. When training with the screen, shooting percentages increased. We conclude that visual control training is an effective method to improve wheelchair basketball shooting. The findings support the idea that perceptual-motor learning can be enhanced by manipulating relevant constraints in the training environment, even for expert athletes.

  4. Value addition to bamboo shoots: a review.

    PubMed

    Choudhury, Debangana; Sahu, Jatindra K; Sharma, G D

    2012-08-01

    Bamboo shoot forms a traditional delicacy in many countries. Being low in fat content and high in potassium, carbohydrate, dietary fibres, Vitamins and active materials, bamboo shoots are consumed in raw, canned, boiled, marinated, fermented, frozen, liquid and medicinal forms. Although the fresh bamboo shoots of species like Dendraocalamus giganteus are healthier and nutritionally rich, the young shoots, after fortification, can be consumed by processing into a wide range of food products with longer shelf-life and better organoleptic qualities. However, the consumption pattern of bamboo shoots in most of the countries is traditional, non-standardized, seasonal and region-specific with little value addition. Therefore, there exists a great opportunity, especially for the organized food processing sectors to take up the processing of bamboo shoot-based food products in an organized manner. The present article gives an insight into the global scenario of bamboo shoot-based food products and their consumption pattern, the quality attributes, and the opportunities for value addition along with future prospects in view of international food safety, security and nutrition.

  5. Safe! Sports, Campers & Reducing Sports Injuries.

    ERIC Educational Resources Information Center

    Thomson, Beth J.

    1989-01-01

    Acceptance of adult roles by children increases "adult injuries," notably broken bones from sports. Suggests camp administrators be familiar with clientele, particular sports, and the kinds of injuries that generally result in each. Discusses children's age, types of sports, and other factors that come into play when anticipating and treating…

  6. Building Character through Sports

    ERIC Educational Resources Information Center

    Lumpkin, Angela

    2011-01-01

    Sports are a focus of millions of Americans as they attend, view, and participate in sports. The World Series, Final Four, and Super Bowl often bring back memories of fun-filled parties and celebrations, but there may be several reasons why sports are so popular in the United States. The popularity of sports, however, does not necessarily mean it…

  7. Perspectives on Sport Specialization.

    ERIC Educational Resources Information Center

    Watts, Jay

    2002-01-01

    For high school athletes, the pressure increases each year to specialize and focus on their best sport, and if they do not, they risk being surpassed by other athletes who have focused on one sport. This paper discusses the advantages and disadvantages of sport specialization and looks at the rising danger of club sports for high school athletes.…

  8. Sport Sociology: Contemporary Themes.

    ERIC Educational Resources Information Center

    Yiannakis, Andrew, Ed.; And Others

    Intended for beginning and intermediate level students of sport and society, this anthology of 43 articles is organized into twelve, self-contained teaching units with unit introductions and study questions. Topics addressed include: (1) the sociological study of sport; (2) sport and American society; (3) the interdependence of sport, politics,…

  9. Sports Medicine in China.

    ERIC Educational Resources Information Center

    Bloomquist, Lorraine E.

    This report on a visit to the People's Republic of China in April 1985 to explore methodology of sports science research, treatment of injuries, and role of sports in everyday life discusses the following topics: (1) introduction to China; (2) sports and physical culture; (3) sports medicine and rehabilitation; (4) health factors; (5) cost of…

  10. Microforms and Sport History.

    ERIC Educational Resources Information Center

    Levine, Peter

    1986-01-01

    Explores the importance of sport history as it reflects the social and cultural history of the United States. Discussion covers the various sport history materials that are available in microform, including the Spalding Collection, twentieth-century microfilm sources, and sports and social history (Sports Periodicals microfilm series). (EJS)

  11. Enhancement in Sport, and Enhancement outside Sport

    PubMed Central

    Douglas, Thomas

    2009-01-01

    Sport is one of the first areas in which enhancement has become commonplace. It is also one of the first areas in which the use of enhancement technologies has been heavily regulated. Some have thus seen sport as a testing ground for arguments about whether to permit enhancement. However, I argue that there are fairness-based objections to enhancement in sport that do not apply as strongly in some other areas of human activity. Thus, I claim that there will often be a stronger case for permitting enhancement outside of sport than for permitting enhancement in sport. I end by considering some methodological implications of this conclusion. PMID:19750128

  12. Trouble shooting system for an electric vehicle

    SciTech Connect

    Horiuchi, M.

    1986-01-14

    This patent describes a trouble shooting system for an electric vehicle. The electric vehicle contains a driving mechanism, a driving operation part and a control device. The driving mechanism includes a power source, an electric motor and a modality for controlling output level from the power supply to the electric motor in response to the driving operation part. The control device includes a microprocessor which receives commands from the driving operation part and supplies a control signal to the driving mechanism in response to a stored drive control program. The trouble shooting system consists of control device storage mechanisms for storing trouble shooting programs for various parts of the vehicle which are executed by the microprocessor. This system also includes a command generating modality responsive to manual operation for supplying a command to the microprocessor to initiate the execution and read out of a selected trouble shooting program and a method by which the microprocessor may display the program being processed.

  13. The growth and form of plant shoots

    NASA Astrophysics Data System (ADS)

    Chelakkot, Raghunath; Mahadevan, L.

    2015-03-01

    Growing plant stems and shoots exhibit a variety of shapes that embody growth in response to various stimuli. We provide a quantitative biophysical theory for these shapes by accounting for the inherent observed passive and active effects: (i) the passive elastic deflection of the shoot due to its own weight, and (ii) the active controllable growth response of the shoot in response to its orientation relative to gravity, and (iii) proprioception, the shoot's growth response to its own observable shape, which is itself determined by its elasticity and weight. A morphospace diagram in terms of two dimensionless parameters representing a scaled local active gravitropic sensitivity, and a scaled passive elastic sag shows how a variety of observed transient and steady morphologies with effective positive, negative and even oscillatory gravitropic behaviors arise in a sentient growing filament naturally, without the need for ad-hoc complex spatio-temporal control strategies.

  14. [Genetic regulation of plant shoot stem cells].

    PubMed

    Al'bert, E V; Ezhova, T A

    2013-02-01

    This article describes the main features of plant stem cells and summarizes the results of studies of the genetic control of stem cell maintenance in the apical meristem of the shoot. It is demonstrated that the WUS-CLV gene system plays a key role in the maintenance of shoot apical stem cells and the formation of adventitious buds and somatic embryos. Unconventional concepts of plant stem cells are considered.

  15. Early events in geotropism of seedling shoots

    NASA Technical Reports Server (NTRS)

    Pickard, B. G.

    1985-01-01

    Developments during the first ten minutes of geotropic stimulation in plant seedling shoots are reviewed. Topics include induction and curvature; early processes; the relationship between auxin, electric field, calcium, and differential growth; gravity reception leading to Went-Cholodny transport; and comparison of root and shoot. Early processes reviewed are sedimentation of amyloplasts, release of ethylene, rise of electrical and auxin asymmetry, redistribution of calcium, asymmetric vascular transport, increase in tendency to deposit callose, and simulation of putative exocytotic voltage transients.

  16. Easy transition path sampling methods: flexible-length aimless shooting and permutation shooting.

    PubMed

    Mullen, Ryan Gotchy; Shea, Joan-Emma; Peters, Baron

    2015-06-09

    We present new algorithms for conducting transition path sampling (TPS). Permutation shooting rigorously preserves the total energy and momentum of the initial trajectory and is simple to implement even for rigid water molecules. Versions of aimless shooting and permutation shooting that use flexible-length trajectories have simple acceptance criteria and are more computationally efficient than fixed-length versions. Flexible-length permutation shooting and inertial likelihood maximization are used to identify the reaction coordinate for vacancy migration in a two-dimensional trigonal crystal of Lennard-Jones particles. The optimized reaction coordinate eliminates nearly all recrossing of the transition state dividing surface.

  17. The ultraviolet photochemistry of diacetylene - Direct detection of primary products of the metastable C4H2* + C4H2 reaction

    NASA Technical Reports Server (NTRS)

    Bandy, Ralph E.; Lakshminarayan, Chitra; Frost, Rex K.; Zwier, Timothy S.

    1993-01-01

    The products of diacetylene's ultraviolet photochemistry over the 245-220 nm region were directly determined in experiments where C4H2 was excited within a small reaction tube attached to a pulsed nozzle. The products formed in the collisions of C4H2* with C4H2 were subsequently ionized by vacuum UV radiation (at 118 nm) in the ion source of a time-of-flight mass spectrometer. It was found that the reaction of C4H2* with C4H2 produces C6H2 (+C2H2), C8H2 (+2H,H2), and C8H3 (+H), confirming the results of Glicker and Okabe (1987). Under certain conditions, secondary products were observed. Mechanisms for the observed reactions are proposed.

  18. Perceptions of Texas 4-H Livestock Ambassadors on Career Development, Higher Education, and Leadership Development

    ERIC Educational Resources Information Center

    Zanolini, William F.; Rayfield, John; Ripley, Jeff

    2013-01-01

    Selected 4-H youth participated in the Texas 4-H Livestock Ambassador program. Forty-five youth participated in the 3-day program delivered by university professors and staff, Texas AgriLife Extension faculty and industry representatives. An instrument was developed and administered to the Texas 4-H Livestock Ambassadors at the end of their first…

  19. Perceptions of Missouri 4-H Youth Development Personnel Regarding Interorganizational Cooperative Behavior

    ERIC Educational Resources Information Center

    McKim, Billy R.; Torres, Robert M.

    2011-01-01

    Perceptions of 4-H youth development personnel regarding interorganizational cooperation were studied between the perceived and desired levels of cooperative activities between 4-H youth development personnel and secondary agriculture teachers. Results indicated that 4-H youth development personnel wanted higher levels of coordinated efforts…

  20. Using the Delphi Technique to Assess Educational Needs Related to Extension's 4-H Beef Program.

    ERIC Educational Resources Information Center

    Shih, Ching-Chun; Gamon, Julia A.

    1997-01-01

    Delphi panels completing questionnaires included 32 parents of 4-H students, 16 extension beef specialists, 21 4-H field specialists, and 21 industry representatives. They identified 31 subject-matter and 30 life-skill topics useful for 4-H manuals. Emerging topics included consumer and environmental concerns. (SK)

  1. Examination of Attitude and Interest Measures for 4-H Science Evaluation

    ERIC Educational Resources Information Center

    Lewis, Kendra M.; Worker, Steven M.

    2015-01-01

    Science education research has demonstrated the influence of affect on learning. The National 4-H Science Logic Model outlines outcomes from youth participation in 4-H science programs, which includes attitude and interest outcomes. The associated measure, the National 4-H Science Common Measure, assesses these attitude constructs and not other…

  2. Expression analysis of kenaf cinnamate 4-hydroxylase (C4H) ortholog during developmental and stress responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to clone and analyze the expression pattern of a C4H gene encoding cinnamate 4-hydroxylase from kenaf (Hibiscus cannabinus L.). A full-length C4H ortholog was cloned using degenerate primers and the RACE (rapid amplification of cDNA ends) method. The full-length C4H ortholog...

  3. Understanding the Knowledge and Use of Experiential Learning within Pennsylvania 4-H Clubs

    ERIC Educational Resources Information Center

    Bechtel, Robyn; Ewing, John C.; Threeton, Mark; Mincemoyer, Claudia

    2013-01-01

    Experiential learning is incorporated into the National 4-H curriculum. However, the state 4-H staff in Pennsylvania is unsure of the current knowledge and use of experiential learning within the local 4-H clubs. An online survey was distributed to Extension educators and volunteer leaders within Pennsylvania to assess the current knowledge and…

  4. Stewardship as a Means to Create Organizational Reform: A View into Minnesota 4-H Youth Development

    ERIC Educational Resources Information Center

    Skuza, Jennifer A.; Freeman, Dorothy M.; Bremseth, Tamara J.; Doering, Shirley A.; Quinlan, Robert B.; Morreim, Patricia A.; Deidrick, James C.

    2010-01-01

    Minnesota 4-H Youth Development (MN 4-H) used stewardship as a means to create organizational reform to address the public use of the 4-H name and emblem in terms of risk management, real estate and equipment, and finances. A task force implemented a participatory process with colleagues and stakeholders to build and implement the reform effort.…

  5. External barrel temperature of a small bore olympic rifle and shooting precision.

    PubMed

    Gladyszewska, B; Baranowski, P; Mazurek, W; Wozniak, J; Gladyszewski, G

    2013-03-01

    Investigations on changes in a rifle's barrel temperature during shooting in a rhythm typical for practitioners of Olympic shooting sports are presented. Walther KK300 (cal. 5.6 mm), a typical rifle often used in Olympic competitions, R50 RWS ammunition and a high speed thermographic camera were used in the study. Altair version 5 software was used to process thermal images and a stationary wavelet transform was applied to denoise signals for all the studied points. It was found that the temperature of the rifle barrel does not exceed 0.3°C after one shot whereas the total temperature increase does not exceed 5°C after taking 40 shots and does not affect the position of the hitting point on a target. In fact, contrary to popular belief, the so-called "warming shots" are not done for barrel heating but for cleaning of remnants in the barrel.

  6. [Sports medicine in Germany].

    PubMed

    Dickhuth, H-H

    2005-08-01

    Sports medicine covers many different aspects, ranging from clinical specialties, such as internal medicine, orthopedics or pediatrics to physiology and sports sciences. The requirements for sports medicine evolve mainly from exercise physiology (elite, leisure and health oriented physical activity), orthopedics and traumatology as well as from preventive and rehabilitative issues. In the new German curriculum, sports medicine is defined as a subspecialty. Historically, sports medicine in Germany has a federal structure with a governing body (Deutsche Gesellschaft für Sportmedizin und Prävention). Due to these facts, University Departments of Sports Medicine (which vary greatly in size and performance) are either attached to Medical or non-Medical Faculties, such as Sports Sciences. In medical schools, sports medicine can be selected as an elective subject. However, the main part of teaching sports medicine is covered by Sports Science Faculties. In an international context, the strength of German sports medicine is its clinical orientation and close cooperation with the sport itself, especially high-performance sports. In the future, like in the Anglo- American countries, sports medicine in Germany will play a major role in health prevention and rehabilitation.

  7. Sports dentistry: A review

    PubMed Central

    Ramagoni, Naveen Kumar; Singamaneni, Vijaya Kumar; Rao, Saketh Rama; Karthikeyan, Jamini

    2014-01-01

    Dental trauma in sports is the major linking channel between sports and dentistry. Sports dentistry is the prevention of oral/facial athletic injuries and related oral diseases and manifestations. In children, sports activities were found to be responsible for 13% of overall oral trauma. It is emphasized that there is a great need for “Team Dentist” from high schools to professional teams. In this review, we discuss the relationship between sports and dentistry, and the importance of educating parents, teachers, and children in prevention of injuries related to the sports. PMID:25625070

  8. Shooting Mechanisms in Nature: A Systematic Review

    PubMed Central

    Sakes, Aimée; van der Wiel, Marleen; Henselmans, Paul W. J.; van Leeuwen, Johan L.; Dodou, Dimitra; Breedveld, Paul

    2016-01-01

    Background In nature, shooting mechanisms are used for a variety of purposes, including prey capture, defense, and reproduction. This review offers insight into the working principles of shooting mechanisms in fungi, plants, and animals in the light of the specific functional demands that these mechanisms fulfill. Methods We systematically searched the literature using Scopus and Web of Knowledge to retrieve articles about solid projectiles that either are produced in the body of the organism or belong to the body and undergo a ballistic phase. The shooting mechanisms were categorized based on the energy management prior to and during shooting. Results Shooting mechanisms were identified with projectile masses ranging from 1·10−9 mg in spores of the fungal phyla Ascomycota and Zygomycota to approximately 10,300 mg for the ballistic tongue of the toad Bufo alvarius. The energy for shooting is generated through osmosis in fungi, plants, and animals or muscle contraction in animals. Osmosis can be induced by water condensation on the system (in fungi), or water absorption in the system (reaching critical pressures up to 15.4 atmospheres; observed in fungi, plants, and animals), or water evaporation from the system (reaching up to −197 atmospheres; observed in plants and fungi). The generated energy is stored as elastic (potential) energy in cell walls in fungi and plants and in elastic structures in animals, with two exceptions: (1) in the momentum catapult of Basidiomycota the energy is stored in a stalk (hilum) by compression of the spore and droplets and (2) in Sphagnum energy is mainly stored in compressed air. Finally, the stored energy is transformed into kinetic energy of the projectile using a catapult mechanism delivering up to 4,137 J/kg in the osmotic shooting mechanism in cnidarians and 1,269 J/kg in the muscle-powered appendage strike of the mantis shrimp Odontodactylus scyllarus. The launch accelerations range from 6.6g in the frog Rana pipiens to 5

  9. Ontogeny of the maize shoot apical meristem.

    PubMed

    Takacs, Elizabeth M; Li, Jie; Du, Chuanlong; Ponnala, Lalit; Janick-Buckner, Diane; Yu, Jianming; Muehlbauer, Gary J; Schnable, Patrick S; Timmermans, Marja C P; Sun, Qi; Nettleton, Dan; Scanlon, Michael J

    2012-08-01

    The maize (Zea mays) shoot apical meristem (SAM) arises early in embryogenesis and functions during stem cell maintenance and organogenesis to generate all the aboveground organs of the plant. Despite its integral role in maize shoot development, little is known about the molecular mechanisms of SAM initiation. Laser microdissection of apical domains from developing maize embryos and seedlings was combined with RNA sequencing for transcriptomic analyses of SAM ontogeny. Molecular markers of key events during maize embryogenesis are described, and comprehensive transcriptional data from six stages in maize shoot development are generated. Transcriptomic profiling before and after SAM initiation indicates that organogenesis precedes stem cell maintenance in maize; analyses of the first three lateral organs elaborated from maize embryos provides insight into their homology and to the identity of the single maize cotyledon. Compared with the newly initiated SAM, the mature SAM is enriched for transcripts that function in transcriptional regulation, hormonal signaling, and transport. Comparisons of shoot meristems initiating juvenile leaves, adult leaves, and husk leaves illustrate differences in phase-specific (juvenile versus adult) and meristem-specific (SAM versus lateral meristem) transcript accumulation during maize shoot development. This study provides insight into the molecular genetics of SAM initiation and function in maize.

  10. The reinvestigation of the kinetics of the metathesis reactions t-C4H9• + HBr (HI) → i-C4H10 + Br• (I•) and of the t-C4H9• free radical thermochemistry.

    PubMed

    Leplat, N; Rossi, M J

    2014-07-17

    A reinvestigation of the absolute rate constant of the metathesis reactions t-C4H9• + HBr → i-C4H10 + Br• (1) and t-C4H9• + HI → i-C4H10 + I• (2) was performed thanks to a recently developed apparatus consisting of a Knudsen reactor coupled to detection based on single-photon (VUV) photoionization mass spectrometry (SPIMS). It enables the generation of thermalized hydrocarbon free radicals owing to a source upstream of and external to the Knudsen reactor. The following Arrhenius expressions were obtained: k1 = 5.6(±1.4) × 10(–12) exp(−6.76(±0.94)/(RT)) and k2 = 2.0(±0.6) × 10(–11) exp(−8.48(±0.94)/(RT)) with R = 8.314 J mol(–1) K(–1) over the range 293 to 623 K. The mass balance of the reaction system based on closed shell product detection (CSPD) was checked in order to ensure the accuracy of the used reaction mechanism and as an independent check of k1 and k2. The wall-loss rate constants of the t-butyl free radical, kw(C4H9), were measured and found to be low compared with the corresponding escape rate constant, ke(C4H9), for effusion of t-C4H9• out of the Knudsen reactor. On the basis of the present results, the free radical standard heat of formation ΔfH298°(t-C4H9•) = 44.3 ± 1.7 kJ mol(–1) was obtained when combined with the kinetics of the inverse halogenation reaction taken from the literature and using S298°(t-C4H9•) = 322.2 J K(–1) mol(–1) following a “Third Law” evaluation method. The standard enthalpy for t-butyl free radical is consistent for both the bromination and iodination reactions within the stated uncertainties.

  11. Quantitative Analysis of Shoot Development and Branching Patterns in Actinidia

    PubMed Central

    SELEZNYOVA, ALLA N.; THORP, T. GRANT; BARNETT, ANDREW M.; COSTES, EVELYNE

    2002-01-01

    We developed a framework for the quantitative description of Actinidia vine architecture, classifying shoots into three types (short, medium and long) corresponding to the modes of node number distribution and the presence/absence of neoformed nodes. Short and medium shoots were self‐terminated and had only preformed nodes. Based on the cut‐off point between their two modes of node number distribution, short shoots were defined as having nine or less nodes, and medium shoots as having more than nine nodes. Long shoots were non‐terminated and had a number of neoformed nodes; the total number of nodes per shoot was up to 90. Branching patterns for each parent shoot type were represented by a succession of branching zones. Probabilities of different types of axillary production (latent bud, short, medium or long shoot) and the distributions of length for each branching zone were estimated from experimental data using hidden semi‐Markov chain stochastic models. Branching was acrotonic on short and medium parent shoots, with most axillary shoots being located near the shoot tip. For long parent shoots, branching was mesotonic, with most long axillary shoots being located in the transition zone between the preformed and neoformed part of the parent shoot. Although the shoot classification is based on node number distribution there was a marked difference in average (per shoot) internode length between the shoot types, with mean values of 9, 27 and 47 mm for short, medium and long shoots, respectively. Bud and shoot development is discussed in terms of environmental controls. PMID:12096808

  12. BOREAS TE-12 SSA Shoot Geometry Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Walter-Shea, Elizabeth A.; Mesarch, Mark A.; Cheng, L.; Yang, Litao

    2000-01-01

    The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-12 (Terrestrial Ecology) team collected shoot geometry data in 1993 and 1994 from aspen, jack pine, and black spruce trees. Collections were made at the Southern Study Area Nipawin Fen Site (SSA FEN), Young Jack Pine (YJP), Old Jack Pine (OJP), Old Aspen (OA), Young Aspen (YA), Mixed Site (MIX), and Old Black Spruce (OBS) sites. A caliper was used to measure shoot and needle lengths and widths. A volume displacement procedure was used to measure the weight of the shoot or twig submerged in water. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  13. Sports and Concussions

    MedlinePlus

    ... A Week of Healthy Breakfasts Shyness Sports and Concussions KidsHealth > For Teens > Sports and Concussions Print A ... completely helps prevent long-term problems. How Do Concussions Happen? The brain is soft. The body protects ...

  14. Champions of American Sport.

    ERIC Educational Resources Information Center

    Westin, Sandra

    1981-01-01

    Describes an exhibition (originating at the Smithsonian Institution) which celebrates athletes and sports-related figures who became legends in their own time. Information is presented on art works, sports memorabilia, advertising posters, and photographs. (AM)

  15. International Understanding Through Sports

    ERIC Educational Resources Information Center

    McNamara, William G.

    1977-01-01

    The American Council on International Sports (ACIS), with a State Department grant, planned, organized, and conducted a program designed to revolutionize physical education and sports in all Iranian public schools. Some of the results are discussed. (LBH)

  16. [Supporting health through sports].

    PubMed

    Truong, Laurent

    2014-02-01

    In spring 2013, the regional directorate for youth, sports and social cohesion and the regional healthcare agency in Franche-Comté presented and signed the first regional health, sports and well-being plan.

  17. Sports and Your Eyes

    MedlinePlus

    ... for Kids > Sports and Your Eyes All About Vision About the Eye Ask a Scientist Video Series ... Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun ...

  18. Contagion in Mass Killings and School Shootings

    PubMed Central

    Towers, Sherry; Gomez-Lievano, Andres; Khan, Maryam; Mubayi, Anuj; Castillo-Chavez, Carlos

    2015-01-01

    Background Several past studies have found that media reports of suicides and homicides appear to subsequently increase the incidence of similar events in the community, apparently due to the coverage planting the seeds of ideation in at-risk individuals to commit similar acts. Methods Here we explore whether or not contagion is evident in more high-profile incidents, such as school shootings and mass killings (incidents with four or more people killed). We fit a contagion model to recent data sets related to such incidents in the US, with terms that take into account the fact that a school shooting or mass murder may temporarily increase the probability of a similar event in the immediate future, by assuming an exponential decay in contagiousness after an event. Conclusions We find significant evidence that mass killings involving firearms are incented by similar events in the immediate past. On average, this temporary increase in probability lasts 13 days, and each incident incites at least 0.30 new incidents (p = 0.0015). We also find significant evidence of contagion in school shootings, for which an incident is contagious for an average of 13 days, and incites an average of at least 0.22 new incidents (p = 0.0001). All p-values are assessed based on a likelihood ratio test comparing the likelihood of a contagion model to that of a null model with no contagion. On average, mass killings involving firearms occur approximately every two weeks in the US, while school shootings occur on average monthly. We find that state prevalence of firearm ownership is significantly associated with the state incidence of mass killings with firearms, school shootings, and mass shootings. PMID:26135941

  19. Brain activation patterns of motor imagery reflect plastic changes associated with intensive shooting training.

    PubMed

    Baeck, Jong-Su; Kim, Yang-Tae; Seo, Jee-Hye; Ryeom, Hun-Kyu; Lee, Jongmin; Choi, Sung-Mook; Woo, Minjung; Kim, Woojong; Kim, Jin Gu; Chang, Yongmin

    2012-09-01

    Evidence from previous studies has suggested that motor imagery and motor action engage overlapping brain systems. As a result of this observation that motor imagery can activate brain regions associated with actual motor movement, motor imagery is expected to enhance motor skill performance and become an underlying principle for physical training in sports and physical rehabilitation. However, few studies have examined the effects of physical training on motor imagery in beginners. Also, differences in neural networks related to motor imagery before and after training have seldom been studied. In the current study, using functional magnetic resonance imaging (fMRI), we investigated the question of whether motor imagery can reflect plastic changes of neural correlates associated with intensive training. In fact, motor imagery was used in this study as a tool to assess the brain areas involved in shooting and involved in learning of shooting. We discovered that use of motor imagery resulted in recruitment of widely distributed common cortical areas, which were suggested to play a role in generation and maintenance of mental images before and after 90 h of shooting training. In addition to these common areas, brain activation before and after 90 h of shooting practice showed regionally distinct patterns of activity change in subcortical motor areas. That is, basal ganglia showed increased activity after 90 h of shooting practice, suggesting the occurrence of plastic change in association with gains in performance and reinforcement learning. Therefore, our results suggest that, in order to reach a level of expertise, the brain would change through initial reinforcement of preexistent connections during the training period and then use more focused neural correlates through formation of new connections.

  20. Sport Specialization, Part I

    PubMed Central

    Myer, Gregory D.; Jayanthi, Neeru; Difiori, John P.; Faigenbaum, Avery D.; Kiefer, Adam W.; Logerstedt, David; Micheli, Lyle J.

    2015-01-01

    Context: There is increased growth in sports participation across the globe. Sports specialization patterns, which include year-round training, participation on multiple teams of the same sport, and focused participation in a single sport at a young age, are at high levels. The need for this type of early specialized training in young athletes is currently under debate. Evidence Acquisition: Nonsystematic review. Study Design: Clinical review. Level of Evidence: Level 4. Conclusion: Sports specialization is defined as year-round training (greater than 8 months per year), choosing a single main sport, and/or quitting all other sports to focus on 1 sport. Specialized training in young athletes has risks of injury and burnout, while the degree of specialization is positively correlated with increased serious overuse injury risk. Risk factors for injury in young athletes who specialize in a single sport include year-round single-sport training, participation in more competition, decreased age-appropriate play, and involvement in individual sports that require the early development of technical skills. Adults involved in instruction of youth sports may also put young athletes at risk for injury by encouraging increased intensity in organized practices and competition rather than self-directed unstructured free play. Strength-of-Recommendation Taxonomy (SORT): C. PMID:26502420

  1. [Violence in Sports].

    ERIC Educational Resources Information Center

    Degelman, Charles, Ed.; Hayes, Bill, Ed.

    1994-01-01

    This teaching resource presents articles that draw on young people's natural interest in sports to stimulate their involvement in law-related education. An article on violence in sports explores the causes of this violence--the physical contact inherent in many sports, the desire to win at all costs, the urging of coaches, and the negligence of…

  2. Cold-Weather Sports

    MedlinePlus

    ... Surgery? A Week of Healthy Breakfasts Shyness Cold-Weather Sports KidsHealth > For Teens > Cold-Weather Sports Print A A A What's in this ... Equipment Ahh, winter! Shorter days. Frigid temperatures. Foul weather. What better time to be outdoors? Winter sports ...

  3. Researching Sport Education Appreciatively

    ERIC Educational Resources Information Center

    Pill, Shane; Hastie, Peter

    2016-01-01

    In order to plan and enact appropriate learning environments in physical education (PE) teachers are increasingly directed to models based practice. The Sport Education model is one of these models for PE curriculum and teaching design that informs the content and pedagogical direction of sport teaching in PE. Despite Sport Education being well…

  4. Violence in Sports.

    ERIC Educational Resources Information Center

    Cooper, Donald L.

    Increasing violence in sports is deplored, and a warning is issued on an apparent trend toward antisocial behavior. Contact sports such as hockey and football are cited as typically engendering aggression among athletes, but spectator sports (boxing, car racing, basketball, and baseball) are also singled out as eliciting increasing violence on the…

  5. Sport for Older Persons.

    ERIC Educational Resources Information Center

    Council of Europe, Strasbourg (France).

    The following papers were prepared for a seminar on sport for older people: (1) "Gerontological Aspects of Physical Exercise" (Eino Heikkinen); (2) "Sporting Activities in the Individual Life from the View of Older Persons" (Henning Allmer); (3) "Reasons Why Decision-Makers Should Urge Old People to Practise Physical and Sporting Activities"…

  6. Sports Facility Management.

    ERIC Educational Resources Information Center

    Walker, Marcia L., Ed.; Stotlar, David K., Ed.

    The numbers of both sports facility management college courses and sport and exercise facilities are increasing, along with the need for an understanding of the trends and management concepts of these facilities. This book focuses exclusively on managing facilities where sporting events occur and includes examples in physical education, athletics,…

  7. Synthesis of 4H/fcc-Au@Metal Sulfide Core-Shell Nanoribbons.

    PubMed

    Fan, Zhanxi; Zhang, Xiao; Yang, Jian; Wu, Xue-Jun; Liu, Zhengdong; Huang, Wei; Zhang, Hua

    2015-09-02

    Although great advances on the synthesis of Au-semiconductor heteronanostructures have been achieved, the crystal structure of Au components is limited to the common face-centered cubic (fcc) phase. Herein, we report the synthesis of 4H/fcc-Au@Ag2S core-shell nanoribbon (NRB) heterostructures from the 4H/fcc Au@Ag NRBs via the sulfurization of Ag. Remarkably, the obtained 4H/fcc-Au@Ag2S NRBs can be further converted to a novel class of 4H/fcc-Au@metal sulfide core-shell NRB heterostructures, referred to as 4H/fcc-Au@MS (M = Cd, Pb or Zn), through the cation exchange. We believe that these novel 4H/fcc-Au@metal sulfide NRB heteronanostructures may show some promising applications in catalysis, surface enhanced Raman scattering, solar cells, photothermal therapy, etc.

  8. 7 CFR 8.9 - Use in 4-H fund raising.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Food and Agriculture, United States Department of Agriculture, or a designee, if the fund-raising... 7 Agriculture 1 2014-01-01 2014-01-01 false Use in 4-H fund raising. 8.9 Section 8.9 Agriculture Office of the Secretary of Agriculture 4-H CLUB NAME AND EMBLEM § 8.9 Use in 4-H fund raising. (a)...

  9. 7 CFR 8.9 - Use in 4-H fund raising.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Food and Agriculture, United States Department of Agriculture, or a designee, if the fund-raising... 7 Agriculture 1 2012-01-01 2012-01-01 false Use in 4-H fund raising. 8.9 Section 8.9 Agriculture Office of the Secretary of Agriculture 4-H CLUB NAME AND EMBLEM § 8.9 Use in 4-H fund raising. (a)...

  10. 7 CFR 8.9 - Use in 4-H fund raising.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Food and Agriculture, United States Department of Agriculture, or a designee, if the fund-raising... 7 Agriculture 1 2013-01-01 2013-01-01 false Use in 4-H fund raising. 8.9 Section 8.9 Agriculture Office of the Secretary of Agriculture 4-H CLUB NAME AND EMBLEM § 8.9 Use in 4-H fund raising. (a)...

  11. 4-H PetPALS Juvenile Diversion Program Supports At-Risk Youth and Seniors

    ERIC Educational Resources Information Center

    Goble, Connie L.; Miller, Lucinda B.

    2014-01-01

    The 4-H PetPALS Juvenile Diversion Program provides a partnership opportunity with Extension and the juvenile court system to positively impact lives of at-risk youth. At-risk youth are taught by 4-H PetPALS adult volunteer leaders and 4-H PetPALS members to value and respect the human-animal bond, as well as to understand and empathize with…

  12. Safety in Outdoor Recreational Activities. Sports Safety Series, Monograph No. 6.

    ERIC Educational Resources Information Center

    Borozne, Joseph, Ed.; And Others

    Safety procedures are outlined for the following sports: (1) fishing; (2) hunting and shooting; (3) skeet and trap; (4) hiking and mountaineering; (5) ice fishing; (6) ice skating; (7) skiing; (8) snowmobiling; (9) recreational motorcycling; and (10) developmental and play activities. (JD)

  13. Physiological Disorders of Pear Shoot Cultures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Physiological disorders are some of the most difficult challenges in micropropagation. Little is known of the causes of plant growth disorders which include callus formation, hyperhydricity, shoot tip necrosis, leaf lesions, epinasty, fasciation and hypertrophy. During our study of mineral nutritio...

  14. Shooting Gallery Notes. Working Paper #22. Preliminary.

    ERIC Educational Resources Information Center

    Bourgois, Philippe

    This paper contains ethnographic participant-observation field notes taken on a one-night visit to a "shooting gallery" in East Harlem (New York City) along with background information and commentary. East Harlem, also referred to as "El Barrio" or Spanish Harlem, is a 200-square block neighborhood on the upper East Side of…

  15. Auditory risk estimates for youth target shooting

    PubMed Central

    Meinke, Deanna K.; Murphy, William J.; Finan, Donald S.; Lankford, James E.; Flamme, Gregory A.; Stewart, Michael; Soendergaard, Jacob; Jerome, Trevor W.

    2015-01-01

    Objective To characterize the impulse noise exposure and auditory risk for youth recreational firearm users engaged in outdoor target shooting events. The youth shooting positions are typically standing or sitting at a table, which places the firearm closer to the ground or reflective surface when compared to adult shooters. Design Acoustic characteristics were examined and the auditory risk estimates were evaluated using contemporary damage-risk criteria for unprotected adult listeners and the 120-dB peak limit suggested by the World Health Organization (1999) for children. Study sample Impulses were generated by 26 firearm/ammunition configurations representing rifles, shotguns, and pistols used by youth. Measurements were obtained relative to a youth shooter’s left ear. Results All firearms generated peak levels that exceeded the 120 dB peak limit suggested by the WHO for children. In general, shooting from the seated position over a tabletop increases the peak levels, LAeq8 and reduces the unprotected maximum permissible exposures (MPEs) for both rifles and pistols. Pistols pose the greatest auditory risk when fired over a tabletop. Conclusion Youth should utilize smaller caliber weapons, preferably from the standing position, and always wear hearing protection whenever engaging in shooting activities to reduce the risk for auditory damage. PMID:24564688

  16. School Shootings; Standards Kill Students and Society

    ERIC Educational Resources Information Center

    Angert, Betsy L.

    2008-01-01

    School shootings have been in the news of late. People ponder what occurs in classrooms today. Why would a young person wish to take a life? Within educational institutions, the killings are a concern. In our dire attempt to teach the children and ensure student success, it seems many of our offspring are lost. Some students feel separate from…

  17. Microdissection of Shoot Meristem Functional Domains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The shoot apical meristem (SAM) maintains a pool of indeterminate cells within the SAM proper, while lateral organs are initiated from the SAM periphery. Laser microdissection–microarray technology was used to compare transcriptional profiles within these SAM domains to identify novel maize genes th...

  18. Microdissection of Shoot Meristem Functional Domains

    PubMed Central

    Zhang, Xiaolan; Ohtsu, Kazuhiro; Zhou, Ruilian; Sarkar, Ananda; Hargreaves, Sarah; Elshire, Robert J.; Eudy, Douglas; Pawlowska, Teresa; Ware, Doreen; Janick-Buckner, Diane; Buckner, Brent; Timmermans, Marja C. P.; Schnable, Patrick S.; Nettleton, Dan; Scanlon, Michael J.

    2009-01-01

    The shoot apical meristem (SAM) maintains a pool of indeterminate cells within the SAM proper, while lateral organs are initiated from the SAM periphery. Laser microdissection–microarray technology was used to compare transcriptional profiles within these SAM domains to identify novel maize genes that function during leaf development. Nine hundred and sixty-two differentially expressed maize genes were detected; control genes known to be upregulated in the initiating leaf (P0/P1) or in the SAM proper verified the precision of the microdissections. Genes involved in cell division/growth, cell wall biosynthesis, chromatin remodeling, RNA binding, and translation are especially upregulated in initiating leaves, whereas genes functioning during protein fate and DNA repair are more abundant in the SAM proper. In situ hybridization analyses confirmed the expression patterns of six previously uncharacterized maize genes upregulated in the P0/P1. P0/P1-upregulated genes that were also shown to be downregulated in leaf-arrested shoots treated with an auxin transport inhibitor are especially implicated to function during early events in maize leaf initiation. Reverse genetic analyses of asceapen1 (asc1), a maize D4-cyclin gene upregulated in the P0/P1, revealed novel leaf phenotypes, less genetic redundancy, and expanded D4-CYCLIN function during maize shoot development as compared to Arabidopsis. These analyses generated a unique SAM domain-specific database that provides new insight into SAM function and a useful platform for reverse genetic analyses of shoot development in maize. PMID:19424435

  19. Microdissection of shoot meristem functional domains.

    PubMed

    Brooks, Lionel; Strable, Josh; Zhang, Xiaolan; Ohtsu, Kazuhiro; Zhou, Ruilian; Sarkar, Ananda; Hargreaves, Sarah; Elshire, Robert J; Eudy, Douglas; Pawlowska, Teresa; Ware, Doreen; Janick-Buckner, Diane; Buckner, Brent; Timmermans, Marja C P; Schnable, Patrick S; Nettleton, Dan; Scanlon, Michael J

    2009-05-01

    The shoot apical meristem (SAM) maintains a pool of indeterminate cells within the SAM proper, while lateral organs are initiated from the SAM periphery. Laser microdissection-microarray technology was used to compare transcriptional profiles within these SAM domains to identify novel maize genes that function during leaf development. Nine hundred and sixty-two differentially expressed maize genes were detected; control genes known to be upregulated in the initiating leaf (P0/P1) or in the SAM proper verified the precision of the microdissections. Genes involved in cell division/growth, cell wall biosynthesis, chromatin remodeling, RNA binding, and translation are especially upregulated in initiating leaves, whereas genes functioning during protein fate and DNA repair are more abundant in the SAM proper. In situ hybridization analyses confirmed the expression patterns of six previously uncharacterized maize genes upregulated in the P0/P1. P0/P1-upregulated genes that were also shown to be downregulated in leaf-arrested shoots treated with an auxin transport inhibitor are especially implicated to function during early events in maize leaf initiation. Reverse genetic analyses of asceapen1 (asc1), a maize D4-cyclin gene upregulated in the P0/P1, revealed novel leaf phenotypes, less genetic redundancy, and expanded D4-CYCLIN function during maize shoot development as compared to Arabidopsis. These analyses generated a unique SAM domain-specific database that provides new insight into SAM function and a useful platform for reverse genetic analyses of shoot development in maize.

  20. Adventure and Extreme Sports.

    PubMed

    Gomez, Andrew Thomas; Rao, Ashwin

    2016-03-01

    Adventure and extreme sports often involve unpredictable and inhospitable environments, high velocities, and stunts. These activities vary widely and include sports like BASE jumping, snowboarding, kayaking, and surfing. Increasing interest and participation in adventure and extreme sports warrants understanding by clinicians to facilitate prevention, identification, and treatment of injuries unique to each sport. This article covers alpine skiing and snowboarding, skateboarding, surfing, bungee jumping, BASE jumping, and whitewater sports with emphasis on epidemiology, demographics, general injury mechanisms, specific injuries, chronic injuries, fatality data, and prevention. Overall, most injuries are related to overuse, trauma, and environmental or microbial exposure.

  1. AB INITIO CHARACTERIZATION OF C{sup -}{sub 4}, C{sub 4}H, AND C{sub 4}H{sup -}

    SciTech Connect

    Senent, M. L.

    2010-01-10

    Using state-of-the-art theoretical methods, we investigate the stable isomers of C{sup -}{sub 4}, C{sub 4}H and C{sub 4}H{sup -}. Three of them are relevant for astrophysics and astrochemistry. These computations are performed using highly correlated ab initio methods and the aug-cc-pVXZ (X = T,Q) basis sets. In addition to the linear isomers, we predict the existence of several cyclic and branched forms for these molecules. For all the molecular species of interest here, sets of spectroscopic parameters are determined with perturbation theory, which compare quite well with experiment. For l - C{sub 4}H{sup -}(X {sup 1}SIGMA{sup +}), the quartic force field is computed at the coupled cluster level of theory. This force field is derived from full nine-dimensional potential energy surface generated close to the equilibrium geometry of this anion. Finally, we treat the thermochemistry of the hydrogen attachment and the electron attachment reactions that may lead to the formation of the C{sub 4}H{sup -} from either C{sup -}{sub 4} or C{sub 4}H.

  2. Sports eyewear protective standards.

    PubMed

    Dain, Stephen J

    2016-01-01

    Eye injuries sustained during sport comprise up to 20 per cent of all injuries to the eye serious enough for medical attention to be sought. The prevalence of eye injuries in sport is not easily assessed due to lack of authoritative participation rates, so most studies report total numbers in a time period. The evidence on the proportion of all ocular injuries that are from sport is reviewed. The relative frequencies in different sports are compared in a qualitative manner and the sports with greater numbers of ocular injuries are detailed. In common with occupational injuries to the eye, most sports eye injuries are considered preventable. The hierarchy of action for occupational risk is detailed and adapted to use in a sports scenario. All the available international, regional and national standards on sports eye protection are detailed and their provisions compared. The major function of the standards is to provide adequate protection against the hazard of the sport concerned. These are detailed and compared as a function of energy transfer. Eye protection must not introduce additional or secondary hazards (for instance, fracturing into sharp fragments on impact) and not introduce features that would deter the wearing of eye protection (for instance, restricting field of view to impede playing the sport). The provisions of the standards intended to limit secondary hazards are detailed and compared. The need for future work in standards writing and the activities of the International Standardization Organization in sports eye protection are detailed.

  3. American Medical Society for Sports Medicine recommended sports ultrasound curriculum for sports medicine fellowships.

    PubMed

    Finnoff, Jonathan T; Berkoff, David; Brennan, Fred; DiFiori, John; Hall, Mederic M; Harmon, Kimberly; Lavallee, Mark; Martin, Sean; Smith, Jay; Stovak, Mark

    2015-02-01

    The American Medical Society for Sports Medicine (AMSSM) developed a musculoskeletal ultrasound curriculum for sports medicine fellowships in 2010. As the use of diagnostic and interventional ultrasound in sports medicine has evolved, it became clear that the curriculum needed to be updated. Furthermore, the name 'musculoskeletal ultrasound' was changed to 'sports ultrasound' (SPORTS US) to reflect the broad range of diagnostic and interventional applications of ultrasound in sports medicine. This document was created to outline the core competencies of SPORTS US and to provide sports medicine fellowship directors and others interested in SPORTS US education with a guide to create a SPORTS US curriculum. By completing this SPORTS US curriculum, sports medicine fellows and physicians can attain proficiency in the core competencies of SPORTS US required for the practice of sports medicine.

  4. Shooting under cardiovascular load: Electroencephalographic activity in preparation for biathlon shooting.

    PubMed

    Gallicchio, Germano; Finkenzeller, Thomas; Sattlecker, Gerold; Lindinger, Stefan; Hoedlmoser, Kerstin

    2016-11-01

    This study explored the influence of sub-maximal cardiovascular load on electroencephalographic (EEG) activity preceding biathlon shooting. Frontal-midline theta and alpha power were examined to assess monitoring processes and cortical inhibition, respectively. Thirteen experienced biathletes (mean age: 17years; 5 males, 8 females) fired sets of five consecutive shots from the standing position at a 50-meter-distant target, under two fixed-order conditions: (i) at rest and (ii) immediately after 3-minute exercise on a bicycle ergometer at 90% of maximum heart rate (HR). HR and rate of physical exertion (RPE) were measured as manipulation checks. Shooting accuracy was assessed in target rings for each shot. Frontal-midline theta and alpha power were computed in the last second preceding each shot from average-reference 61-channel EEG and inter-individual differences were minimized through a median-scaled log transformation (Appendix). HR and RPE increased under cardiovascular load, however, shooting accuracy did not change. Pre-shooting frontal-midline theta power decreased, whereas alpha power increased over temporal and occipital - but not central - regions. These changes were larger for greater HR values. Additionally, higher frontal-midline theta, lower left-central alpha, and higher left-temporal alpha power were associated with more accurate shooting. These findings suggest that monitoring processes are beneficial to shooting performance but can be impaired by sub-maximal cardiovascular load. Greater inhibition of movement-irrelevant regions (temporal, occipital) and concomitant activation of movement-related regions (central) indicate that greater neural efficiency is beneficial to shooting performance and can allow trained biathletes to shoot accurately despite physically demanding conditions.

  5. Comparison of eSports and Traditional Sports Consumption Motives

    ERIC Educational Resources Information Center

    Lee, Donghun; Schoenstedt, Linda J.

    2011-01-01

    With recognition of the need for studying eSports in this interactive digital communication era, this study explored 14 motivational factors affecting the time spent on eSports gaming. Using a sample of 515 college students and athletic event attendees, we further compared eSports game patterns to their non-eSport or traditional sport involvements…

  6. Identification with sports teams by fans of women's sports.

    PubMed

    Nelson, Kelly

    2004-10-01

    Previous studies on why sports fans identify with a particular team have focused on fans of men's sports teams. This study examined why fans favor a particular women's sports team. Based on survey responses from 273 self-identified fans of women's sports, athletes are most frequently cited as the reason for choosing a favorite women's sports team.

  7. Junior Sport and the Evolution of Sport Cultures.

    ERIC Educational Resources Information Center

    Siedentop, Daryl

    2002-01-01

    Addresses junior sport and sport culture in New Zealand, recommending that it receive serious consideration for its crucial role in the future of New Zealand's sport culture. The paper presents three goals for junior sport programs (educative, public health, and elite development), describes characteristics of junior sport (e.g., youth want to…

  8. 4-H and Tech Ed Partnership Gets Students Geeked about STEM

    ERIC Educational Resources Information Center

    Ivey, Debra; Quam, Greg

    2009-01-01

    This article discusses the 4-H Gateway Academies specifically designed to enhance science, technology, engineering, and math (STEM) skills and knowledge in middle school youth. The innovative summer day camps partnered Project Lead the Way--trained teachers with county 4-H staff from University of Wisconsin-Extension (UW-Extension) Cooperative…

  9. 4-H and Forestry Afterschool Clubs: A Collaboration to Foster Stewardship Attitudes and Behaviors in Youth

    ERIC Educational Resources Information Center

    Gupta, Angela S.; Grant, Samantha; Strauss, Andrea Lorek

    2012-01-01

    The University of Minnesota Extension's 4-H and Forestry Afterschool program combined the 4-H structure and various forestry curricula to foster positive attitudes towards the environment and stewardship-related behaviors as these may serve as precursors to later choices that benefit the environment. Evaluation of third through fifth grade club…

  10. 4-H Youth Development: The Past, the Present, and the Future

    ERIC Educational Resources Information Center

    Borden, Lynne M.; Perkins, Daniel F.; Hawkey, Kyle

    2014-01-01

    The 4-H Program within Cooperative Extension is more than 100 years old. As we celebrate 100 years of Cooperative Extension, the foundation built by the 4-H Program serves as grounds to meet the needs of today's youth. The diversity of the youth who participate continues to grow, families continue to become less traditional, potential…

  11. Cinnamate 4-Hydroxylase (C4H) genes from Leucaena leucocephala: a pulp yielding leguminous tree.

    PubMed

    Kumar, Santosh; Omer, Sumita; Patel, Krunal; Khan, Bashir M

    2013-02-01

    Leucaena leucocephala is a leguminous tree species accounting for one-fourth of raw material supplied to paper and pulp industry in India. Cinnamate 4-Hydroxylase (C4H, EC 1.14.13.11) is the second gene of phenylpropanoid pathway and a member of cytochrome P450 family. There is currently intense interest to alter or modify lignin content of L. leucocephala. Three highly similar C4H alleles of LlC4H1 gene were isolated and characterized. The alleles shared more than 98 % sequence identity at amino acid level to each other. Binding of partial promoter of another C4H gene LlC4H2, to varying amounts of crude nuclear proteins isolated from leaf and stem tissues of L. leucocephala formed two loose and one strong complex, respectively, suggesting that the abundance of proteins that bind with the partial C4H promoter is higher in stem tissue than in leaf tissue. Quantitative Real Time PCR study suggested that among tissues of same age, root tissues had highest level of C4H transcripts. Maximum transcript level was observed in 30 day old root tissue. Among the tissues investigated, C4H activity was highest in 60 day old root tissues. Tissue specific quantitative comparison of lignin from developing seedling stage to 1 year old tree stage indicated that Klason lignin increased in tissues with age.

  12. Food Challenge: Serving Up 4-H to Non-Traditional Audiences

    ERIC Educational Resources Information Center

    Dodd, Sara; Follmer-Reece, Holly E.; Kostina-Ritchey, Erin; Reyna, Roxanna

    2015-01-01

    This article describes a novel approach for introducing 4-H to non-traditional/diverse audiences using 4-H Food Challenge. Set in a low SES and minority-serving rural school, Food Challenge was presented during the school day to all 7th grade students, with almost half voluntarily participating in an after-school club component. Program design…

  13. Characteristics and Perceptions of 4-H Participants: Gender and Age Differences across Adolescence

    ERIC Educational Resources Information Center

    Bartoszuk, Karin; Randall, Brandy A.

    2011-01-01

    The study reported here examined 367 adolescent 4-H participants in terms of demographic, psychological, behavioral, and relational characteristics, as well as their perceptions and experiences in 4-H. Overall, participants scored high on all outcome variables except having a diverse population in their club. Older participants were more…

  14. Birds in Your Backyard. 4-H Leaders Guide. L-5-17.

    ERIC Educational Resources Information Center

    Hawkes, Janet E.; Held Phillips, Diane

    This pocket folder of instructional materials is designed to introduce youth aged 9 to 12 to ornithology, the study of birds. The package includes a 4-H member's guide and a Leader's guide. The illustrated 4-H member's guide contains information about attracting and feeding birds. It also includes activities for cooking for birds, making bird…

  15. The Effects of Age, Gender, and 4-H Involvement on Life Skill Development

    ERIC Educational Resources Information Center

    Haas, Bruce E.; Mincemoyer, Claudia C.; Perkins, Daniel F.

    2015-01-01

    The study reported here examined the effects of age, gender, and 4-H involvement in clubs on life skill development of youth ages eight to 18 over a 12-month period. Regression analyses found age, gender, and 4-H involvement significantly influenced life skill development. Results found that females have higher levels of competencies in life…

  16. 4-H Healthy Living Programs with Impact: A National Environmental Scan

    ERIC Educational Resources Information Center

    Downey, Laura H.; Peterson, Donna J.; LeMenestrel, Suzanne; Leatherman, JoAnne; Lang, James

    2014-01-01

    The 4-H youth development program of the nation's 109 land-grant universities and the Cooperative Extension System is one of the largest youth development organization in the United States serving approximately six million youth. The 4-H Healthy Living initiative began in 2008 to promote achievement of optimal physical, social, and emotional…

  17. The 4-H Debate Project: Getting Adults and Children Involved in Communication.

    ERIC Educational Resources Information Center

    Atwater, Deborah F.

    Intended to enhance adult leadership skills, the 4-H Debate Project, developed by the 4-H Communication Committee of Delaware County (Pennsylvania), was designed to (1) increase the members' knowledge of library skills through research, (2) make them aware of current issues, (3) help them to become better public speakers and communicators, (4)…

  18. An Examination of 4-H Youths' Needs and Interests, and Implications for State Conference.

    ERIC Educational Resources Information Center

    Rude, Tarri Lou

    A study was conducted to determine the needs and interests of teens in 4-H and whether the Washington State Conference is meeting those needs and interests. A mail survey was developed and sent to 557 teen 4-H members in Washington who were randomly selected from the 1985 state enrollment list. Three hundred and sixty questionnaires were returned…

  19. 7 CFR 8.9 - Use in 4-H fund raising.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...-raising programs using the 4-H Name or Emblem may be carried out for specific educational purposes. Such... Research, Education, and Extension Service, United States Department of Agriculture, or a designee, if the fund-raising program is multi-State or Nationwide. (b) When used to promote 4-H educational...

  20. Fitting the Framework: The STEM Institute and the 4-H Essential Elements

    ERIC Educational Resources Information Center

    Sallee, Jeff; Peek, Gina G.

    2014-01-01

    Extension and 4-H youth development programs are addressing a shortage of scientists, engineers, and other related professionals by promoting science, technology, engineering, and math (STEM). This case study illustrates how the Oklahoma 4-H Youth Development program trained youth-adult teams to design and implement STEM projects. The STEM…

  1. Bringing Carnaval Drum and Dance Traditions into 4-H Programming for Latino Youth

    ERIC Educational Resources Information Center

    Conklin-Ginop, Evelyn; Braverman, Marc T.; Caruso, Robyn; Bone, Dennis

    2011-01-01

    4-H Bloco Drum and Dance is an afterschool program that teaches adolescents drumming, dancing, and theater arts in the rich traditions of Brazilian Carnaval. Teens learn to express themselves in a variety of modalities and perform at community events. The program was developed by a community coalition that included 4-H, other youth programs, and…

  2. Factors Related to the Developmental Experiences of Youth Serving as 4-H Camp Counselors

    ERIC Educational Resources Information Center

    Carter, David N.; Kotrlik, Joe W.

    2008-01-01

    The purpose of this study was to investigate the developmental experiences of high-school-aged 4-H youth volunteering as counselors at Louisiana 4-H summer camps. A total of 288 counselors from 10 different camping sessions participated in the study. The Youth Experiences Survey 2.0 and the Developmental Experience Survey measured the personal…

  3. Unusual reaction paths of SN2 nucleophile substitution reactions CH4 + H- → CH4 + H- and CH4 + F- → CH3F + H-: Quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Minyaev, Ruslan M.; Quapp, Wolfgang; Schmidt, Benjamin; Getmanskii, Ilya V.; Koval, Vitaliy V.

    2013-11-01

    Quantum chemical (CCSD(full)/6-311++G(3df,3pd), CCSD(T)(full)/6-311++G(3df,3pd)) and density function theory (B3LYP/6-311++G(3df,3pd)) calculations were performed for the SN2 nucleophile substitution reactions CH4 + H- → CH4 + H- and CH4 + F- → CH3F + H-. The calculated gradient reaction pathways for both reactions have an unusual behavior. An unusual stationary point of index 2 lies on the gradient reaction path. Using Newton trajectories for the reaction path, we can detect VRI point at which the reaction path branches.

  4. Volumetric Properties of the Mixture Oxolan-2-one C4H6O2 + C4H10O Butan-1-ol (VMSD1511, LB4906_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Oxolan-2-one C4H6O2 + C4H10O Butan-1-ol (VMSD1511, LB4906_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  5. Structural analysis of the 3C|4H boundaries formed on prismatic planes in 4H-SiC epitaxial films

    NASA Astrophysics Data System (ADS)

    Yamashita, T.; Matsuhata, H.; Naijo, T.; Momose, K.; Osawa, H.

    2016-12-01

    The boundaries between 3C and 4H-SiC domains on the prismatic planes of hexagonal lattices formed in a 4H-SiC epitaxial film were investigated using both transmission and scanning transmission electron microscopy. These observations determined that the boundaries have a periodic structure, in which each unit cell consists of 12 basal planes of the hexagonal lattice. Six Shockley partial dislocations are situated in each unit cell of the boundary structure. Burgers vectors and core structures of these partial dislocations are discussed.

  6. Ultra high voltage MOS controlled 4H-SiC power switching devices

    NASA Astrophysics Data System (ADS)

    Ryu, S.; Capell, C.; Van Brunt, E.; Jonas, C.; O'Loughlin, M.; Clayton, J.; Lam, K.; Pala, V.; Hull, B.; Lemma, Y.; Lichtenwalner, D.; Zhang, Q. J.; Richmond, J.; Butler, P.; Grider, D.; Casady, J.; Allen, S.; Palmour, J.; Hinojosa, M.; Tipton, C. W.; Scozzie, C.

    2015-08-01

    Ultra high voltage (UHV, >15 kV) 4H-silicon carbide (SiC) power devices have the potential to significantly improve the system performance, reliability, and cost of energy conversion systems by providing reduced part count, simplified circuit topology, and reduced switching losses. In this paper, we compare the two MOS based UHV 4H-SiC power switching devices; 15 kV 4H-SiC MOSFETs and 15 kV 4H-SiC n-IGBTs. The 15 kV 4H-SiC MOSFET shows a specific on-resistance of 204 mΩ cm2 at 25 °C, which increased to 570 mΩ cm2 at 150 °C. The 15 kV 4H-SiC MOSFET provides low, temperature-independent, switching losses which makes the device more attractive for applications that require higher switching frequencies. The 15 kV 4H-SiC n-IGBT shows a significantly lower forward voltage drop (VF), along with reasonable switching performance, which make it a very attractive device for high voltage applications with lower switching frequency requirements. An electrothermal analysis showed that the 15 kV 4H-SiC n-IGBT outperforms the 15 kV 4H-SiC MOSFET for applications with switching frequencies of less than 5 kHz. It was also shown that the use of a carrier storage layer (CSL) can significantly improve the conduction performance of the 15 kV 4H-SiC n-IGBTs.

  7. Wiggles and Wags: Dog 1--Fun Activities for You and Your Dog. 4-H Skills for Life Animal Series. National 4-H Curriculum. BU-08166

    ERIC Educational Resources Information Center

    National 4-H Council, 2005

    2005-01-01

    These guides are activity guides. Several fact-filled books about dogs are listed as resources on this guide. The activities are active, hands-on, and engaging and are guided by the 4-H motto: Learning by Doing. As youth explore a dog project topic of interest to them, they also practice essential life skills. Although a few dog project youth will…

  8. Burn disasters in shooting range areas.

    PubMed

    Uygur, Fatih; Oksüz, Sinan; Yüksel, Fuat

    2008-08-06

    Shooting range injuries are generally caused by ballistic accidents, and so far no burn disaster has been reported. In this article we reported a disaster caused by a gunpowder explosion in an indoor shooting range area in Istanbul, Turkey. Fourteen injured people were evacuated from the scene. Our burn center accepted 7 of them. Of the 7 injured people, 2 who were accepted by our burn center, and 3 people who were admitted by another center died. It is clearly identified how this mechanism of injury differs from that of usual burn injuries, due to both the high temperature generated, and the combination of hot and toxic gases produced by the explosion. We described the features of burn injury, and possible reasons of burn disasters.

  9. Root : shoot ratios, optimization and nitrogen productivity.

    PubMed

    Agren, Göran I; Franklin, Oskar

    2003-12-01

    Plants respond to nitrogen availability by changing their root : shoot ratios. One hypothesis used to explain this allocation is that plants optimize their behaviour by maximizing their relative growth rate. The consequences of this hypothesis were investigated by formulating two models for root : shoot allocation, with and without explicit inclusion of maintenance respiration. The models also took into account that relative growth rate is a linear function of plant nitrogen concentration. The model without respiration gave qualitatively reasonable results when predictions were compared with observed results from growth experiments with birch and tomato. The explicit inclusion of maintenance respiration improved considerably the agreement between prediction and observation, and for birch was within the experimental accuracy. Further improvements will require additional details in the description of respiratory processes and the nitrogen uptake function. Plants growing under extreme nutrient stress may also optimize their behaviour with respect to other variables in addition to relative growth rate.

  10. Shooting direction and crosswell seismic data acquisition

    SciTech Connect

    Liner, C.L.; Bozkurt, G.; Cox, V.D.

    1994-12-31

    At the Glenn Pool field in Northeastern Oklahoma, a series of crosswell seismic surveys have been acquired. The acquisition parameters and shooting geometry were careful developed using a test survey. The first full survey resulted in high quality data, but the second encountered high ambient noise. The noise levels were high enough to prohibit first-arrival picking over in much of the data. Analysis of the data from the second survey shows that tube waves are emanating from the perforated interval in the receiver well. This is interpreted to be fluid flow or circulation noise through the perforations, even though the well was not flowing fluid at the surface. Since this image plane was important for characterization of the reservoir, the survey was re-shot by reversing sources and receivers in the two wells. The resulting high-quality data indicates that shooting direction can be an important acquisition factor.

  11. The Effects of Different Media on Shoot Proliferation From the Shoot Tip of Aloe vera L.

    PubMed Central

    Daneshvar, Mohammad Hosein; Moallemi, Noorolah; Abdolah Zadeh, Nazanin

    2013-01-01

    Background Aloe vera L. is an important pharmaceutical plant from which several medicinal and cosmetic compounds are extracted. Aloe is naturally propagated through offset, which is a slow and expensive labor cost method with low economical income. Objectives In this study, the effect of different media on shoot proliferation of the shoot tip of Aloe vera L. was investigated. Materials and Methods In vitro techniques are some of the suggested methods for rapid propagation of Aloe. In this experiment, the shoot tips of mother plants were grown in a greenhouse. After surface sterilization of the explants, they were cultured on Murashige and Skoog (1962) (MS) medium containing different concentrations of kinetin and naphthaleneacetic acid (NAA). The experiment was carried out in the form of a randomized complete design with three replications. Results The results showed that MS media containing 1.5 mg/L kinetin along with 0.15 or 0.3 mg/L NAA produced the highest percentage of proliferated shoots. In addition, the percentage of proliferated shoots in MS medium containing 2.0 or 2.5 mg/L benzylaminopurine (BAP) + 0.15 mg/L NAA was significantly higher than the other treatments. Conclusions Analysis of the interactive effects of NAA, kinetin and BAP on shoot proliferation showed that most of the proliferated shoots produced in MS medium containing 1.0 mg/L BAP + 1.0 mg/L kinetin + 0.15 mg/L NAA were significantly different from other treatments. Rooting quality was greater in MS media containing 1.0 mg/L IBA than a 1.0 mg/L NAA treatment. PMID:24624195

  12. Annoyance caused by shooting range noise

    NASA Astrophysics Data System (ADS)

    Levein, B.; Åhrlin, U.

    1988-12-01

    Noise from shooting ranges is characterized by high levels of impulse noise with a large contribution of low frequencies. The knowledge of human reactions to this kind of noise is as yet incomplete. A questionnaire study was performed around one civilian and three military artillery ranges in order to elucidate the annoyance reactions among nearby residents. The extent of annoyance was determined through postal questionnaires. In a first questionnaire, containing general questions about the residential area, persons "annoyed" by "noise from shooting ranges" were identified. A second questionnaire, distributed only to those annoyed by the noise, contained more detailed questions concerning the annoyance reaction. A total of 299 persons participated in the study. Among the residents in the vicinity of the three artillery ranges, 31-35% reported that they were "very annoyed" by the noise. Corresponding data for the civilian shooting range was 15%. The characteristics of the exposure most frequently reported as the main source of annoyance was "heavy weapons" and "vibrations" in all areas. Furthermore, the annoyance reactions were most frequently experienced in the evening and night hours. Establishment of dose-response relationships was not considered relevant due to the small number of areas studied and the similarity in exposure levels (around 85 dB(A) FAST expressed as peak levels). The results of the study demonstrate that noise from shooting ranges, especially such with a large contribution of heavy weapons, is a potential source of great annoyance. Further studies have been initiated in order to obtain a wider distribution of peak levels which will enable the establishment of dose-response relationships.

  13. Ethics in sports medicine.

    PubMed

    Dunn, Warren R; George, Michael S; Churchill, Larry; Spindler, Kurt P

    2007-05-01

    Physicians have struggled with the medical ramifications of athletic competition since ancient Greece, where rational medicine and organized athletics originated. Historically, the relationship between sport and medicine was adversarial because of conflicts between health and sport. However, modern sports medicine has emerged with the goal of improving performance and preventing injury, and the concept of the "team physician" has become an integral part of athletic culture. With this distinction come unique ethical challenges because the customary ethical norms for most forms of clinical practice, such as confidentiality and patient autonomy, cannot be translated easily into sports medicine. The particular areas of medical ethics that present unique challenges in sports medicine are informed consent, third parties, advertising, confidentiality, drug use, and innovative technology. Unfortunately, there is no widely accepted code of sports medicine ethics that adequately addresses these issues.

  14. Twenty-first century learning after school: the case of 4-H.

    PubMed

    Kress, Cathann

    2006-01-01

    Founded in the early 1900s, the 4-H Youth Development program can serve as a model for out-of-school programs of the twenty-first century. The 4-H pledge, repeated by its members--over 7 million, ranging in age from five to twenty--articulates its core values: "I pledge: My head to clearer thinking, My heart to greater loyalty, My hands to larger service, and My health to better living for my club, my community, my country, and my world." The 4-H Development movement was created to provide opportunities for rural children, to help them become constructive adults. Through an emphasis on "learning by doing," 4-H teaches children the habits of lifelong learning. Historically, 4-H has tapped into university-level advancements, extending such knowledge to youth and thereby giving them early access to scientific discoveries and technological progress. Members apply this learning in their communities through hands-on projects crossing a wide-range of pertinent topics. Research shows that 4-H members are more successful in school than other children and develop a wide range of skills essential in the twenty-first century. Thus, the author makes the case that the foundation of 4-H is exceptionally relevant in today's complex world, perhaps even more so than a century ago. 4-H is a leader in youth development, making it a natural model for twenty-first century after-school programs. Expanding on the 4-H pledge, the author outlines the principles a successful youth development program would have: an emphasis on leadership skills, a feeling of connection and belonging, a forum for exploring career opportunities, and a component of meaningful community service.

  15. Olympic Information in the SPORT Database.

    ERIC Educational Resources Information Center

    Belna, Alison M.; And Others

    1984-01-01

    Profiles the SPORT database, produced by Sport Information Resource Centre, Ottawa, Ontario, which provides extensive coverage of individual sports including practice, training and equipment, recreation, sports medicine, physical education, sport facilities, and international sport history. Olympic coverage in SPORT, sports sciences, online…

  16. Sports Specialization, Part II

    PubMed Central

    Myer, Gregory D.; Jayanthi, Neeru; DiFiori, John P.; Faigenbaum, Avery D.; Kiefer, Adam W.; Logerstedt, David; Micheli, Lyle J.

    2016-01-01

    Context: Many coaches, parents, and children believe that the best way to develop elite athletes is for them to participate in only 1 sport from an early age and to play it year-round. However, emerging evidence to the contrary indicates that efforts to specialize in 1 sport may reduce opportunities for all children to participate in a diverse year-round sports season and can lead to lost development of lifetime sports skills. Early sports specialization may also reduce motor skill development and ongoing participation in games and sports as a lifestyle choice. The purpose of this review is to employ the current literature to provide evidence-based alternative strategies that may help to optimize opportunities for all aspiring young athletes to maximize their health, fitness, and sports performance. Evidence Acquisition: Nonsystematic review with critical appraisal of existing literature. Study Design: Clinical review. Level of Evidence: Level 4. Conclusion: Based on the current evidence, parents and educators should help provide opportunities for free unstructured play to improve motor skill development and youth should be encouraged to participate in a variety of sports during their growing years to influence the development of diverse motor skills. For those children who do choose to specialize in a single sport, periods of intense training and specialized sport activities should be closely monitored for indicators of burnout, overuse injury, or potential decrements in performance due to overtraining. Last, the evidence indicates that all youth should be involved in periodized strength and conditioning (eg, integrative neuromuscular training) to help them prepare for the demands of competitive sport participation, and youth who specialize in a single sport should plan periods of isolated and focused integrative neuromuscular training to enhance diverse motor skill development and reduce injury risk factors. Strength of Recommendation Taxonomy (SORT): B. PMID

  17. Ocular injuries in sports.

    PubMed

    Cass, Shane P

    2012-01-01

    Eye injuries are common in sports. Team physicians need to be able to recognize and treat common injuries and know when to refer other problems. This article highlights the current treatment of common sports-related eye injuries and reviews some of the new literature. Nearly 90% of all sports-related eye injuries can be prevented with adequate eye protection and will be discussed in some detail in the article.

  18. Timing of growth inhibition following shoot inversion in Pharbitis nil

    NASA Technical Reports Server (NTRS)

    Abdel-Rahman, A. M.; Cline, M. G.

    1989-01-01

    Shoot inversion in Pharbitis nil results in the enhancement of ethylene production and in the inhibition of elongation in the growth zone of the inverted shoot. The initial increase in ethylene production previously was detected within 2 to 2.75 hours after inversion. In the present study, the initial inhibition of shoot elongation was detected within 1.5 to 4 hours with a weighted mean of 2.4 hours. Ethylene treatment of upright shoots inhibited elongation in 1.5 hours. A cause and effect relationship between shoot inversion-enhanced ethylene production and inhibition of elongation cannot be excluded.

  19. HIF-P4H-2 deficiency protects against skeletal muscle ischemia-reperfusion injury.

    PubMed

    Karsikas, Sara; Myllymäki, Mikko; Heikkilä, Minna; Sormunen, Raija; Kivirikko, Kari I; Myllyharju, Johanna; Serpi, Raisa; Koivunen, Peppi

    2016-03-01

    We show here that mice hypomorphic for hypoxia-inducible factor prolyl 4-hydroxylase-2 (HIF-P4H-2) (Hif-p4h-2 (gt/gt)), the main regulator of the stability of the HIFα subunits, have normoxic stabilization of HIF-1α and HIF-2α in their skeletal muscles. The size of the capillaries, but not their number, was increased in the skeletal muscles of the Hif-p4h-2 (gt/gt) mice, whereas the amount of glycogen was reduced. The expression levels of genes for glycolytic enzymes, glycogen branching enzyme 1 and monocarboxylate transporter 4, were increased in the Hif-p4h-2 (gt/gt) skeletal muscles, whereas no significant increases were detected in the levels of any vasculature-influencing factor studied. Serum lactate levels of the Hif-p4h-2 (gt/gt) mice recovered faster than those of the wild type following exercise. The Hif-p4h-2 (gt/gt) mice had elevated hepatic phosphoenolpyruvate carboxykinase activity, which may have contributed to the faster clearance of lactate. The Hif-p4h-2 (gt/gt) mice had smaller infarct size following limb ischemia-reperfusion injury. The increased capillary size correlated with the reduced infarct size. Following ischemia-reperfusion, glycogen content and ATP/ADP and CrP/Cr levels of the skeletal muscle of the Hif-p4h-2 (gt/gt) mice were higher than in the wild type. The higher glycogen content correlated with increased expression of phosphofructokinase messenger RNA (mRNA) and the increased ATP/ADP and CrP/Cr levels with reduced apoptosis, suggesting that HIF-P4H-2 deficiency supported energy metabolism during ischemia-reperfusion and protection against injury. Key messages: HIF-P4H-2 deficiency protects skeletal muscle from ischemia-reperfusion injury. The mechanisms involved are mediated via normoxic HIF-1α and HIF-2α stabilization. HIF-P4H-2 deficiency increases capillary size but not number. HIF-P4H-2 deficiency maintains energy metabolism during ischemia-reperfusion.

  20. Firearms Safety: Instructor Manual. Shooting Skills Series.

    ERIC Educational Resources Information Center

    Green, Rodney J.; Powell, Cheryl Riley, Ed.

    Although written with the classroom teacher in mind, this learning module on firearms safety can be adapted by leaders of camps, 4-H clubs, outdoor educators, scouting organizations or any workers with junior and senior high school youth. The self-contained unit includes information on the subject, lesson plans, activities, class exercises, tests,…

  1. Al4H7(-) is a resilient building block for aluminum hydrogen cluster materials.

    PubMed

    Roach, P J; Reber, A C; Woodward, W H; Khanna, S N; Castleman, A W

    2007-09-11

    The formation and oxygen etching of Al(n)H(m)(-) clusters are characterized in a flow reactor experiment with first-principles theoretical investigations to demonstrate the exceptional stability of Al(4)H(7)(-). The origin of the preponderance of Al(4)H(7)(-) in the mass spectra of hydrogenated aluminum anions and its resistance to O(2) etching are discussed. Al(4)H(7)(-) is shown to have the ability to bond with ionic partners to form stable hydrides through addition of an alkali atom [XAl(4)H(7) (X = Li-Cs)]. An intuitive model that can predict the existence of stable hydrogenated cluster species is proposed. The potential synthetic utility of the superatom assemblies built on these units is addressed.

  2. Prismatic Slip in PVT-Grown 4H-SiC Crystals

    NASA Astrophysics Data System (ADS)

    Guo, Jianqiu; Yang, Yu; Raghothamachar, Balaji; Kim, Jungyu; Dudley, Michael; Chung, Gilyong; Sanchez, Edward; Quast, Jeffrey; Manning, Ian

    2017-04-01

    Basal plane slip is the most frequently observed deformation mechanism in 4H-type silicon carbon (4H-SiC) single crystals grown by the physical vapor transport (PVT) method. However, it was recently reported that dislocations in such crystals can also glide in prismatic slip systems. In this study, we observed nonuniform distributions of three sets of prismatic dislocations in a commercial 4H-SiC substrate wafer. The nonuniformity is a result of the distribution of resolved shear stress on each prismatic slip system caused by radial thermal gradients in the growing crystal boule. A radial thermal model has been developed to estimate the thermal stress across the entire area of the crystal boule during PVT growth. The model results show excellent agreement with the observations, confirming that radial thermal gradients play a key role in activating prismatic slip in 4H-SiC during bulk growth.

  3. Prismatic Slip in PVT-Grown 4H-SiC Crystals

    NASA Astrophysics Data System (ADS)

    Guo, Jianqiu; Yang, Yu; Raghothamachar, Balaji; Kim, Jungyu; Dudley, Michael; Chung, Gilyong; Sanchez, Edward; Quast, Jeffrey; Manning, Ian

    2016-11-01

    Basal plane slip is the most frequently observed deformation mechanism in 4H-type silicon carbon (4H-SiC) single crystals grown by the physical vapor transport (PVT) method. However, it was recently reported that dislocations in such crystals can also glide in prismatic slip systems. In this study, we observed nonuniform distributions of three sets of prismatic dislocations in a commercial 4H-SiC substrate wafer. The nonuniformity is a result of the distribution of resolved shear stress on each prismatic slip system caused by radial thermal gradients in the growing crystal boule. A radial thermal model has been developed to estimate the thermal stress across the entire area of the crystal boule during PVT growth. The model results show excellent agreement with the observations, confirming that radial thermal gradients play a key role in activating prismatic slip in 4H-SiC during bulk growth.

  4. Sport and male sexuality.

    PubMed

    Sgrò, P; Di Luigi, L

    2017-03-22

    The relationships between sport and sexuality in males are of great social and clinical interest, because of sports and motor activities that highly promote social and sexual relationships. Even if few literature exist, two main questions should be taken into account: whether and how physical exercise and sport positively or negatively influence sexual health and behavior and/or whether and how sexual behavior may affect a sub-sequent sport performance. Physical exercise and sport per se can influence, positively or negatively, the hypothalamic-pituitary-testicular axis function and, consequently, the individual's reproductive and/or sexual health. This depends on individual factors such as genetic and epigenetic ones and on different variables involved in the practice of sport activities (type of sport, intensity and duration of training, doping and drug use and abuse, nutrition, supplements, psychological stress, allostatic load, etc.). If well conducted, motor and sport activities could have beneficial effects on sexual health in males. Among different lifestyle changes, influencing sexual health, regular physical activity is fundamental to antagonize the onset of erectile dysfunction (ED). However, competitive sport can lead both reproductive and/or sexual tract damages and dysfunctions, transient (genital pain, hypoesthesia of the genitalia, hypogonadism, DE, altered sexual drive, etc.) or permanent (hypogonadism, DE, etc.), by acting directly (traumas of the external genitalia, saddle-related disorders in cyclists, etc.) or indirectly (exercise-related hypogonadism, drug abuse, doping, stress, etc.). Sexual activities shortly performed before a sport competition could differently influence sport performance. Due to the few existing data, it is advisable to avoid an absolute pre-competition sexual abstinence.

  5. Pb pollution in soils from a trap shooting range and the phytoremediation ability of Agrostis capillaris L.

    PubMed

    Rodríguez-Seijo, Andrés; Lago-Vila, Manoel; Andrade, María Luisa; Vega, Flora A

    2016-01-01

    Pb pollution caused by shooting sport activities is a serious environmental problem that has increased considerably in recent decades. The aims of this study were firstly to analyze Pb pollution in soils from a trap shooting range abandoned in 1999, secondly to study the effectiveness of different extractants [CaCl2, DTPA, NH4OAc, low molecular weight organic acids (LMWOA), and bidistilled water (BDW)] in order to determine Pb bioavailability in these soils, and finally to evaluate the phytoremediation ability of spontaneous vegetation (Agrostis capillaris L.). To this end, 13 soils from an old trap shooting range (Galicia, NW Spain) were studied. It was found that Pb levels in the soils were higher than 100 mg kg(-1), exceeding the generic reference levels, and three of these samples even exceeded the USEPA threshold level (400 mg kg(-1)). In general, the reagent that best represents Pb bioavailability and has the greatest extraction efficiency was CaCl2, followed by DTPA, NH4OAc, LMWOA, and BDW. A. capillaris Pb contents ranged between 9.82 and 1107.42 mg kg(-1) (root) and between 6.43 and 135.23 mg kg(-1) (shoot). Pb accumulation in roots, as well as the presence of secondary mineral phases of metallic Pb in the adjacent soil, showed the phytostabilization properties of A. capillaris.

  6. Enantioselective one-pot synthesis of 2-amino-4-(indol-3-yl)-4H-chromenes.

    PubMed

    Chen, Weiliang; Cai, Yunfei; Fu, Xuan; Liu, Xiaohua; Lin, Lili; Feng, Xiaoming

    2011-09-16

    An enantioselective one-pot synthesis of 2-amino-4-(indol-3-yl)-4H-chromenes via a Knoevenagel/Pinner/Friedel-Crafts reaction of salicylaldehyde, malononitrile, and indole is presented. Moderate to good yields (up to 89%) and high enantioselectivities (up to 90% ee) were obtained with an N,N'-dioxide-Zn(II) complex as the catalyst. This strategy provides an efficient and convenient method to access enantiomerically enriched 2-amino-4H-chromene derivatives.

  7. Phosphorus doping of 4H SiC by liquid immersion excimer laser irradiation

    SciTech Connect

    Ikeda, Akihiro; Nishi, Koji; Ikenoue, Hiroshi; Asano, Tanemasa

    2013-02-04

    Phosphorus doping of 4H SiC is performed by KrF excimer laser irradiation of 4H SiC immersed in phosphoric acid. Phosphorus is incorporated to a depth of a few tens of nanometers at a concentration of over 10{sup 20}/cm{sup 3} without generating significant crystal defects. Formation of a pn junction diode with an ideality factor of 1.06 is demonstrated.

  8. Ferromagnetism in proton irradiated 4H-SiC single crystal

    SciTech Connect

    Zhou, Ren-Wei; Wang, Hua-Jie; Chen, Wei-Bin; Li, Fei; Liu, Xue-Chao Zhuo, Shi-Yi; Shi, Er-Wei

    2015-04-15

    Room-temperature ferromagnetism is observed in proton irradiated 4H-SiC single crystal. An initial increase in proton dose leads to pronounced ferromagnetism, accompanying with obvious increase in vacancy concentration. Further increase in irradiation dose lowers the saturation magnetization with the decrease in total vacancy defects due to the defects recombination. It is found that divacancies are the mainly defects in proton irradiated 4H-SiC and responsible for the observed ferromagnetism.

  9. The development of novel LTA4H modulators to selectively target LTB4 generation

    PubMed Central

    Low, Caroline M.; Akthar, Samia; Patel, Dhiren F.; Löser, Stephan; Wong, Chi-Tung; Jackson, Patricia L.; Blalock, J. Edwin; Hare, Stephen A.; Lloyd, Clare M.; Snelgrove, Robert J.

    2017-01-01

    The pro-inflammatory mediator leukotriene B4 (LTB4) is implicated in the pathologies of an array of diseases and thus represents an attractive therapeutic target. The enzyme leukotriene A4 hydrolase (LTA4H) catalyses the distal step in LTB4 synthesis and hence inhibitors of this enzyme have been actively pursued. Despite potent LTA4H inhibitors entering clinical trials all have failed to show efficacy. We recently identified a secondary anti-inflammatory role for LTA4H in degrading the neutrophil chemoattractant Pro-Gly-Pro (PGP) and rationalized that the failure of conventional LTA4H inhibitors may be that they inadvertently prevented PGP degradation. We demonstrate that these inhibitors do indeed fail to discriminate between the dual activities of LTA4H, and enable PGP accumulation in mice. Accordingly, we have developed novel compounds that potently inhibit LTB4 generation whilst leaving PGP degradation unperturbed. These novel compounds could represent a safer and superior class of LTA4H inhibitors for translation into the clinic. PMID:28303931

  10. Key contribution of eIF4H-mediated translational control in tumor promotion

    PubMed Central

    Vaysse, Charlotte; Philippe, Céline; Martineau, Yvan; Quelen, Cathy; Hieblot, Corinne; Renaud, Claire; Nicaise, Yvan; Desquesnes, Aurore; Pannese, Maria; Filleron, Thomas; Escourrou, Ghislaine; Lawson, Malcolm; Rintoul, Robert C.; Delisle, Marie Bernadette; Pyronnet, Stéphane; Brousset, Pierre; Prats, Hervé; Touriol, Christian

    2015-01-01

    Dysregulated expression of translation initiation factors has been associated with carcinogenesis, but underlying mechanisms remains to be fully understood. Here we show that eIF4H (eukaryotic translation initiation factor 4H), an activator of the RNA helicase eIF4A, is overexpressed in lung carcinomas and predictive of response to chemotherapy. In lung cancer cells, depletion of eIF4H enhances sensitization to chemotherapy, decreases cell migration and inhibits tumor growth in vivo, in association with reduced translation of mRNA encoding cell-proliferation (c-Myc, cyclin D1) angiogenic (FGF-2) and anti-apoptotic factors (CIAP-1, BCL-xL). Conversely, each isoform of eIF4H acts as an oncogene in NIH3T3 cells by stimulating transformation, invasion, tumor growth and resistance to drug-induced apoptosis together with increased translation of IRES-containing or structured 5′UTR mRNAs. These results demonstrate that eIF4H plays a crucial role in translational control and can promote cellular transformation by preferentially regulating the translation of potent growth and survival factor mRNAs, indicating that eIF4H is a promising new molecular target for cancer therapy. PMID:26498689

  11. Synthesis of 4H/fcc Noble Multimetallic Nanoribbons for Electrocatalytic Hydrogen Evolution Reaction.

    PubMed

    Fan, Zhanxi; Luo, Zhimin; Huang, Xiao; Li, Bing; Chen, Ye; Wang, Jie; Hu, Yanling; Zhang, Hua

    2016-02-03

    Noble multimetallic nanomaterials, if only consisting of Au, Ag, Pt, and Pd, typically adopt the high-symmetry face-centered cubic (fcc) structure. Here for the first time, by using the 4H/fcc Au@Ag nanoribbons (NRBs) as seeds, we report the synthesis of 4H/fcc trimetallic Au@PdAg core-shell NRBs via the galvanic reaction method under ambient conditions. Moreover, this strategy can also be used to synthesize 4H/fcc trimetallic Au@PtAg and quatermetallic Au@PtPdAg core-shell NRBs. Impressively, for the first time, these alloy shells, i.e., PdAg, PtAg, and PtPdAg, epitaxially grown on the 4H/fcc Au core with novel 4H hexagonal phase were successfully synthesized. Remarkably, the obtained 4H/fcc Au@PdAg NRBs exhibit excellent electrocatalytic activity toward the hydrogen evolution reaction, which is even quite close to that of the commercial Pt black. We believe that our findings here may provide a novel strategy for the crystal-structure-controlled synthesis of advanced functional noble multimetallic nanomaterials with various promising applications.

  12. The development of novel LTA4H modulators to selectively target LTB4 generation

    NASA Astrophysics Data System (ADS)

    Low, Caroline M.; Akthar, Samia; Patel, Dhiren F.; Löser, Stephan; Wong, Chi-Tung; Jackson, Patricia L.; Blalock, J. Edwin; Hare, Stephen A.; Lloyd, Clare M.; Snelgrove, Robert J.

    2017-03-01

    The pro-inflammatory mediator leukotriene B4 (LTB4) is implicated in the pathologies of an array of diseases and thus represents an attractive therapeutic target. The enzyme leukotriene A4 hydrolase (LTA4H) catalyses the distal step in LTB4 synthesis and hence inhibitors of this enzyme have been actively pursued. Despite potent LTA4H inhibitors entering clinical trials all have failed to show efficacy. We recently identified a secondary anti-inflammatory role for LTA4H in degrading the neutrophil chemoattractant Pro-Gly-Pro (PGP) and rationalized that the failure of conventional LTA4H inhibitors may be that they inadvertently prevented PGP degradation. We demonstrate that these inhibitors do indeed fail to discriminate between the dual activities of LTA4H, and enable PGP accumulation in mice. Accordingly, we have developed novel compounds that potently inhibit LTB4 generation whilst leaving PGP degradation unperturbed. These novel compounds could represent a safer and superior class of LTA4H inhibitors for translation into the clinic.

  13. Alteration in scaling behavior of short-term heartbeat time series for professional shooting athletes from rest to exercise

    NASA Astrophysics Data System (ADS)

    Zhuang, Jian Jun; Ning, Xin Bao; He, Ai Jun; Zou, Ming; Sun, Biao; Wu, Xu Hui

    2008-11-01

    Scaling analysis of heartbeat time series has emerged as a useful tool for assessing the autonomic cardiac control under various physiologic and pathologic conditions. We study the heartbeat activity and scaling behavior of heartbeat fluctuations regulated by autonomic nervous system for professional shooting athletes under two states: rest and exercise, by applying the detrended fluctuation analysis method. We focus on alteration in correlation properties of heartbeat intervals for the shooters from rest to exercise, which may have a potential value in monitoring the quality of training and evaluating the sports capacity of the athletes. The result shows that scaling exponents of short-term heart rate variability signals from the shooters get significantly larger during exercise compared with those obtained at rest. It demonstrates that during exercise stronger correlations appear in the heartbeat series of shooting athletes in order to satisfy the specific requirements for high concentration and better control on their heart beats.

  14. Mathematics and Sports

    ERIC Educational Resources Information Center

    Gallian, Joseph A., Ed.

    2010-01-01

    "Mathematics and Sports", edited by Joseph A. Gallian, gathers 25 articles that illuminate the power and role of mathematics in the worlds of professional and recreational play. Divided into sections by the kind of sports, the book offers source materials for classroom use and student projects. Readers will encounter mathematical ideas from an…

  15. Sport as Yoga

    ERIC Educational Resources Information Center

    Murphy, Michael

    1977-01-01

    The author has written a metaphysical sports fantasy and completed a novel which explores evolutionary transformations of the mind and body. Now he is working on a long-term research project exploring radical bodily transformations occurring in various fields of human experience. This article on sport is part of that project. (Editor/RK)

  16. Eating Disorders and Sports.

    ERIC Educational Resources Information Center

    Moriarty, Dick; Moriarty, Mary

    Since sports can sometimes lend themselves to eating disorders, coaches and sports administrators must get involved in the detection and treatment of this problem. While no reliable studies or statistics exist on the incidence of anorexia nervosa and/or bulimia among athletes, some research suggests that such disorders occur frequently among…

  17. Sport in Higher Education.

    ERIC Educational Resources Information Center

    Committee of Vice-Chancellors and Principals of the Universities of the United Kingdom, London.

    This publication discusses the future of university sport development in the United Kingdom in response to a report of the Department for National Heritage calling for revitalization of British sport at all levels. This report integrates findings and recommendations of a special task force, a government working party, and consultation papers of…

  18. Being Human in Sport.

    ERIC Educational Resources Information Center

    Allen, Dorothy J.; Fahey, Brian W.

    The structure of humanness as the unique and essential being of the individual, constantly emerging through experience and the actualization of human potential within the sports environment, is the central theme of this book. Sport is defined broadly to include all forms of physical activity experiences. Each chapter represents an inquiry unique…

  19. Sports Subsidies Soar. Commentary

    ERIC Educational Resources Information Center

    Toma, J. Douglas

    2010-01-01

    Doug Lederman's article, "Sports Subsidies Soar," discusses the issue on institutional subsidies for sports program. His article invites an obvious question: why are so many universities willing to subsidize athletics through either a direct transfer of institutional funds, assessing a dedicated student fee, or a combination of these? This…

  20. What Are Sports Injuries?

    MedlinePlus

    ... Injuries PDF Version Size: 597 KB Audio Version Time: 06:02 Size: 11.7 MB November 2014 What Are Sports Injuries? Fast Facts: An Easy-to-Read Series of Publications for the Public “Sports injuries” are ...

  1. Scoring Ethically in Sport.

    ERIC Educational Resources Information Center

    Miller, Donna Mae.

    1988-01-01

    This article suggests ways in which coaches, through their coaching and behavior, may preserve, encourage, or improve the integrity and ethics of sports. If coaches model ethical behavior, fans and players may exhibit it as well. Suggestions for promoting sports ethics are given. (JL)

  2. Sports-related concussions.

    PubMed

    Conder, Robert L; Conder, Alanna A

    2015-04-01

    Concussions are an inherent part of collision sports such as football and soccer. As a subset of traumatic brain injury, concussions are neurometabolic events that cause transient neurologic dysfunction. Following a concussion, some athletes require longer neurologic recovery than others. Education and intervention aimed at prevention and management can minimize the long-term sequelae of sports-related concussions.

  3. Saga of American Sport.

    ERIC Educational Resources Information Center

    Lucas, John A.; Smith, Ronald A.

    This history of sports and athletic activities in America covers a time span from the close of the sixteenth century to the present time. It is divided into three major sections. The first, "Colonial and Early American Sport," narrates the early moral and ethical attitudes of the Puritans and follows the changes in attitudes and introduction of…

  4. Prevent Children's Sports Injuries.

    ERIC Educational Resources Information Center

    Micheli, Lyle J.

    1983-01-01

    Children who actively take part in sports are susceptible to special injury risks because their bodies are still growing. Parents should keep both the child's individual physical and emotional makeup and the demands of the sport in mind when selecting an activity. Proper training methods and equipment are discussed. (PP)

  5. Sport Heroes in Congress.

    ERIC Educational Resources Information Center

    Corbett, Doris R.

    This paper reports the findings of a study of the role of sports in the lives of U.S. Congressmen and focuses attention on six gifted athletes for whom sports provided preparation for government service. The word "hero" as used in this paper refers to former members of Congress who were admired for their athletic prowess and for their…

  6. Bamboo shoots: a novel source of nutrition and medicine.

    PubMed

    Singhal, Poonam; Bal, Lalit Mohan; Satya, Santosh; Sudhakar, P; Naik, S N

    2013-01-01

    Bamboos, a group of large woody grasses belonging to the family Poaceae and subfamily Bambusoideae, are much talked about for their contribution to the environment. However, the food potential of Bamboo shoot per se remains unexploited. Literature on the nutritional and medicinal potential of bamboo shoots is scarce. This paper therefore provides insight on bamboo shoot as a food resource. Various edible species and exotic food products (fermented shoots, pickle, etc.) and recipes of bamboo shoots (bamboo beer, bamboo cookies) are consumed worldwide. Change in nutritional composition of different species of bamboo shoots with processing has also been reviewed. Bamboo shoots possess high protein, moderate fiber, and less fat content. They are also endowed for having essential amino acids, selenium, a potent antioxidant, and potassium, a healthy heart mineral. Occurrence of taxiphyllin, a cyanogenic glycoside in raw shoots, and its side effect on human health calls for the demand to innovate processing ways using scientific input to eliminate the toxic compound without disturbing the nutrient reserve. Lastly, the paper also reviews the utilization of medicinal properties acquired by bamboo shoot. Using the traditional knowledge, pharmaceutical preparations of bamboo shoots like bamboo salt, bamboo vinegar, bamboo extracts for diabetes and cholesterol control, etc. are now gaining importance. Further investigation is required by the researchers to make novel nutraceutical products and benefit the society.

  7. Sports: The Infectious Hazards.

    PubMed

    Minooee, Arezou; Wang, Jeff; Gupta, Geeta K

    2015-10-01

    Although the medical complications of sports are usually traumatic in nature, infectious hazards also arise. While blood-borne pathogens such as HIV, hepatitis B, and hepatitis C, cause significant illness, the risk of acquiring these agents during sporting activities is minimal. Skin infections are more commonplace, arising from a variety of microbial agents including bacterial, fungal, and viral pathogens. Sports involving water contact can lead to enteric infections, eye infections, or disseminated infections such as leptospirosis. Mumps, measles, and influenza are vaccine-preventable diseases that have been transmitted during sporting events, both in players and in spectators. Prevention is the key to many of these infections. Players should be vaccinated and should not participate in sports if their infection can be spread by contact, airborne, or droplet transmission.

  8. Overview of sports vision

    NASA Astrophysics Data System (ADS)

    Moore, Linda A.; Ferreira, Jannie T.

    2003-03-01

    Sports vision encompasses the visual assessment and provision of sports-specific visual performance enhancement and ocular protection for athletes of all ages, genders and levels of participation. In recent years, sports vision has been identified as one of the key performance indicators in sport. It is built on four main cornerstones: corrective eyewear, protective eyewear, visual skills enhancement and performance enhancement. Although clinically well established in the US, it is still a relatively new area of optometric specialisation elsewhere in the world and is gaining increasing popularity with eyecare practitioners and researchers. This research is often multi-disciplinary and involves input from a variety of subject disciplines, mainly those of optometry, medicine, physiology, psychology, physics, chemistry, computer science and engineering. Collaborative research projects are currently underway between staff of the Schools of Physics and Computing (DIT) and the Academy of Sports Vision (RAU).

  9. [Arrhythmia and sport].

    PubMed

    Saoudi, N; Yaici, K; Zarkane, N; Darmon, J P; Rinaldi, J P; Brunner, P; Ricard, P; Mourou, M Y

    2005-12-01

    Sports arrhythmia has gained wide attention with the mediatization of the death of famous sports stars. Sport strongly modifies the structure of the heart with the development of left ventricular hypertrophy which may be difficult to differentiate from that due to doping. Intense training modifies also the resting electrocardiogram with appearance of signs of left ventricular hypertrophy whereas resting sinus bradycardia and atrioventricular conduction disturbances usually reverts upon exertion. Accordingly, arrhythmia may develop ranging from extrasystoles to atrial fibrillation and even sudden death. Recent data suggest that if benign arrhythmia may be the result of the sole intense training and are reversible, malignant ventricular arrhythmia and sudden death mostly occur in unknown structural heart disease. Hypertrophic cardiomyopathy is amongst the most frequent post mortem diagnosis in this situation. Doping is now present in many sports and further threatens the athlete in the safe practice of sport.

  10. Effect of expertise in shooting and Taekwondo on bipedal and unipedal postural control isolated or concurrent with a reaction-time task.

    PubMed

    Negahban, Hossein; Aryan, Najmolhoda; Mazaheri, Masood; Norasteh, Ali Asghar; Sanjari, Mohammad Ali

    2013-06-01

    It was hypothesized that training in 'static balance' or 'dynamic balance' sports has differential effects on postural control and its attention demands during quiet standing. In order to test this hypothesis, two groups of female athletes practicing shooting, as a 'static balance' sport, and Taekwondo, as a 'dynamic balance' sport, and a control group of non-physically active females voluntarily participated in this study. Postural control was assessed during bipedal and unipedal stance with and without performing a Go/No-go reaction time task. Visual and/or support surface conditions were manipulated in bipedal and unipedal stances in order to modify postural difficulty. Mixed model analysis of variance was used to determine the effects of dual tasking on postural and cognitive performance. Similar pattern of results were found in bipedal and unipedal stances, with Taekwondo practitioners displaying larger sway, shooters displaying lower sway and non-athletes displaying sway characteristics intermediate to Taekwondo and shooting athletes. Larger effect was found in bipedal stance. Single to dual-task comparison of postural control showed no significant effect of mental task on sway velocity in shooters, indicating less cognitive effort invested in balance control during bipedal stance. We suggest that expertise in shooting has a more pronounced effect on decreased sway in static balance conditions. Furthermore, shooters invest less attention in postures that are more specific to their training, i.e. bipedal stance.

  11. Examining elite Parasport athletes with sport involvement and sports equipment.

    PubMed

    Hambrick, Marion E; Hums, Mary A; Bower, Glenna G; Wolff, Eli A

    2015-01-01

    Elite athletes require the most advanced sports equipment to maintain their competitive edge, but manufacturers cannot always satisfy these athletes' specific equipment needs. Sport involvement can influence sports-equipment selections and is described as the process by which individuals rely on attitudes and belief systems to make sports-related consumption decisions. This study involved semistructured interviews with 5 elite Parasport athletes to identify and analyze the role of sport involvement in their selection of sports equipment. The results revealed that the athletes identified product limitations, created a collaborative environment, and promoted a culture of innovation to develop new sports products and address existing limitations. Theoretical and practical implications are discussed.

  12. Predictors of performance in a 4-h mountain-bike race.

    PubMed

    Novak, Andrew R; Bennett, Kyle J M; Fransen, Job; Dascombe, Ben J

    2017-04-13

    This study aimed to cross validate previously developed predictive models of mountain biking performance in a new cohort of mountain bikers during a 4-h event (XC4H). Eight amateur XC4H cyclists completed a multidimensional assessment battery including a power profile assessment that consisted of maximal efforts between 6 and 600 s, maximal hand grip strength assessments, a video-based decision-making test as well as a XC4H race. A multiple linear regression model was found to predict XC4H performance with good accuracy (R(2) = 0.99; P < 0.01). This model consisted of [Formula: see text] relative to total cycling mass (body mass including competition clothing and bicycle mass), maximum power output sustained over 60 s relative to total cycling mass, peak left hand grip strength and two-line decision-making score. Previous models for Olympic distance MTB performance demonstrated merit (R(2) = 0.93; P > 0.05) although subtle changes improved the fit, significance and normal distribution of residuals within the model (R(2) = 0.99; P < 0.01), highlighting differences between the disciplines. The high level of predictive accuracy of the new XC4H model further supports the use of a multidimensional approach in predicting MTB performance. The difference between the new, XC4H and previous Olympic MTB predictive models demonstrates subtle differences in physiological requirements and performance predictors between the two MTB disciplines.

  13. Organ-specific analysis of the anaerobic primary metabolism in rice and wheat seedlings. I: Dark ethanol production is dominated by the shoots.

    PubMed

    Mustroph, Angelika; Boamfa, Elena I; Laarhoven, Lucas J J; Harren, Frans J M; Albrecht, Gerd; Grimm, Bernhard

    2006-12-01

    During anaerobiosis in darkness the main route for ATP production in plants is through glycolysis in combination with fermentation. We compared the organ-specific anaerobic fermentation of flooding-tolerant rice (Oryza sativa) and sensitive wheat (Triticum aestivum) seedlings. A sensitive laser-based photoacoustic trace gas detection system was used to monitor emission of ethanol and acetaldehyde by roots and shoots of intact seedlings. Dark-incubated rice seedlings released 3 times more acetaldehyde and 14 times more ethanol than wheat seedlings during anaerobiosis. Ninety percent of acetaldehyde originated from shoots of both species. In comparison to wheat shoots, the high ethanol production of rice shoots correlated with larger amounts of soluble carbohydrates, and higher activities of fermentative enzymes. After 24 h of anaerobiosis in darkness rice shoots still contained 30% of aerated ATP level, which enabled seedlings to survive this period. In contrast, ATP content declined almost to zero in wheat shoots and roots, which were irreversibly damaged after a 24-h anaerobic period. When plants were anaerobically and dark incubated for 4 h and subsequently transferred back to aeration, shoots showed a transient peak of acetaldehyde release indicating prompt re-oxidation of ethanol. Post-anoxic acetaldehyde production was lower in rice seedlings than in wheat. This observation accounts for a more effective acetaldehyde detoxification system in rice. Compared to wheat the greater tolerance of rice seedlings to transient anaerobic periods is explained by a faster fermentation rate of their shoots allowing a sufficient ATP production and an efficient suppression of toxic acetaldehyde formation in the early re-aeration period.

  14. [Sport and health].

    PubMed

    Pène, Pierre; Touitou, Yvan

    2009-02-01

    The report of the National Academy of Medicine named "Sport and Health" underlines the medical, social and educational dimensions of sporting activities. Various kinds of sporting practices are described: they concern the approximately 7,000 high level athletes, around 8,000 professional (licensed) sportsmen, and sporting club members (approximately 15 millions people). A large number of amateurs do not practice in any structure and therefore are neither managed in their activities nor medically followed. Some characteristics of sporting practice at various stages of life have been documented. Around 50% of the teenagers from 12 to 17 years have a sporting practice out-of-school besides the weekly three hours applied at school or college; however, the withdrawal of sporting practice by a high number of teenagers results in a sedentary lifestyle with overweight and obesity, major risks factors for health. Elderly people take a profit from a regular and medically controlled physical activity. Functional capacities are thus improved, cardiovascular risks factors among other, which results in better quality of life of the aged and delays their dependence. The benefit upon public health of sporting practice has been pointed out in the primary prevention of cardiovascular and respiratory diseases, osteoporosis, obesity, diabetes, breast and colon cancer, and mood disturbances. It is currently well acknowledged that sporting practice is an important component of public health in both primary and secondary prevention of many diseases. Deleterious effects of which the most serious is the sudden death related to a cardiovascular anomaly, which generally occurs during an important physical effort. An important sport drift is the practice of doping to improve performances through the use of hormones, anabolics, EPO, transfusions, ... When a person exceeds his/her capacities of adaptation, because of a badly adapted or a too intense drive, this overtraining results in a

  15. The Development of Sports Medicine.

    ERIC Educational Resources Information Center

    Waddington, Ivan

    1996-01-01

    The development of sports medicine was influenced by medicalization and increasing competitiveness in modern sport, with sports physicians helping to develop performance enhancing drugs and techniques. This paper discusses sports medicine and drug use in Eastern European countries, early development of anabolic steroids in the United States, and…

  16. Responses of the Mediterranean pine shoot beetle Tomicus destruens (Wollaston) to pine shoot and bark volatiles.

    PubMed

    Faccoli, Massimo; Anfora, Gianfranco; Tasin, Marco

    2008-09-01

    The pine shoot beetle Tomicus destruens has two dispersal phases per generation. In the first, mature adults move toward trunks of dying pines to lay eggs; in the second, callow adults move toward the shoots of healthy pines for maturation feeding. However, there is no information on the chemical stimuli that govern host selection by T. destruens adults. The aims of this study were: (1) to identify the volatiles released by shoots and bark of stone pine that are behaviorally and electrophysiologically active on T. destruens; (2) to verify which blends and concentrations of such volatiles are differently active on males and females, as well as on callow and mature adults, during the two host search phases (breeding and feeding). A four-arm olfactometer was used to test the behavior of walking T. destruens adults toward various sources of volatiles including fresh shoots and bark, their collected volatiles, and two synthetic blends. For each odor, the behavior of both callow and mature males and females was recorded individually. Shoot and bark extracts were analyzed by coupled gas chromatography and mass spectrometry (GC-MS), and tested by gas chromatography coupled with electroantennography (GC-EAD) on T. destruens males and females. Two blends of two (alpha-pinene and beta-myrcene; blend A) and three (alpha-pinene, beta- myrcene, and alpha-terpinolene; blend B) synthetic compounds, chosen among those that induce EAD responses and known to be attractive for other bark beetle species, were tested in the olfactometer at five concentrations. Insect behavior was affected by the degree of sexual maturation but not by sex. Callow insects were attracted by shoots and their extracts, while mature individuals by bark and its extracts. Six extracted compounds were active on T. destruens antennae: limonene, (Z)-3-hexen-1-ol and beta-caryophyllene, alpha-pinene, beta-myrcene, and alpha-terpinolene. alpha-Terpinolene, released only by bark, was active only on mature insects

  17. Formation of polarity convergences underlying shoot outgrowths

    PubMed Central

    Abley, Katie; Sauret-Güeto, Susanna; Marée, Athanasius FM; Coen, Enrico

    2016-01-01

    The development of outgrowths from plant shoots depends on formation of epidermal sites of cell polarity convergence with high intracellular auxin at their centre. A parsimonious model for generation of convergence sites is that cell polarity for the auxin transporter PIN1 orients up auxin gradients, as this spontaneously generates convergent alignments. Here we test predictions of this and other models for the patterns of auxin biosynthesis and import. Live imaging of outgrowths from kanadi1 kanadi2 Arabidopsis mutant leaves shows that they arise by formation of PIN1 convergence sites within a proximodistal polarity field. PIN1 polarities are oriented away from regions of high auxin biosynthesis enzyme expression, and towards regions of high auxin importer expression. Both expression patterns are required for normal outgrowth emergence, and may form part of a common module underlying shoot outgrowths. These findings are more consistent with models that spontaneously generate tandem rather than convergent alignments. DOI: http://dx.doi.org/10.7554/eLife.18165.001 PMID:27478985

  18. Shooting direction and crosswell seismic data acquisition

    SciTech Connect

    Liner, C.L.; Bozkurt, G.; Cox, V.D.

    1996-09-01

    Four crosswell seismic surveys were acquired in the Glenn Pool Field of northeastern Oklahoma as part of a multidisciplinary reservoir characterization project. The acquisition goal was to generate data suitable for tomographic traveltime inversion. Acquisition parameters and shooting geometry were selected by conducting a parameter test at the site. Following the parameter test, the first survey resulted in high quality data showing clear first arrivals, low ambient noise, some reflection events, and strong source-generated tube waves. The second survey involved a different receiver well and encountered high ambient noise levels. The noise was strong enough to prohibit first-arrival picking for much of the data. On-site analysis of the second survey revealed tube waves emanating from a perforated interval in the receiver well. This well was shut in and was not flowing fluid or gas at the surface. They interpret the source of ambient tube waves as borehole-to-formation fluid flow (circulation) associated with the perforations. Since this image plane was important for characterization of the reservoir, the survey was reshot (third survey) by reversing sources and receivers in the two wells. The resulting high-quality data indicates that shooting direction can be an important factor in crosswell seismic acquisition. This experience influenced acquisition of a previously planned fourth survey so that the ambient noise problem would be avoided.

  19. Effect of neutron irradiation on charge collection efficiency in 4H-SiC Schottky diode

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Jiang, Yong; Lei, Jiarong; Fan, Xiaoqiang; Chen, Yu; Li, Meng; Zou, Dehui; Liu, Bo

    2014-01-01

    The charge collection efficiency (CCE) in 4H-SiC Schottky diode is studied as a function of neutron fluence. The 4H-SiC diode was irradiated with fast neutrons of a critical assembly in Nuclear Physics and Chemistry Institute and CCE for 3.5 MeV alpha particles was then measured as a function of the applied reverse bias. It was found from our experiment that an increase of neutron fluence led to a decrease of CCE. In particular, CCE of the diode was less than 1.3% at zero bias after an irradiation at 8.26×1014 n/cm2. A generalized Hecht's equation was employed to analyze CCE in neutron irradiated 4H-SiC diode. The calculations nicely fit the CCE of 4H-SiC diode irradiated at different neutron fluences. According to the calculated results, the extracted electron μτ product (μτ)e and hole μτ product (μτ)h of the irradiated 4H-SiC diode are found to decrease by increasing the neutron fluence.

  20. On the Origin of C4H and CH3OH in Protostellar Envelopes

    NASA Astrophysics Data System (ADS)

    Lindberg, Johan E.; Charnley, Steven B.; Cordiner, Martin A.

    2016-12-01

    The formation pathways of different types of organic molecules in protostellar envelopes and other regions of star formation are subjects of intense current interest. We present here observations of C4H and CH3OH, tracing two distinct groups of interstellar organic molecules, toward 16 protostars in the Ophiuchus and Corona Australis molecular clouds. Together with observations in the literature, we present C4H and CH3OH data from single-dish observations of 40 embedded protostars. We find no correlation between the C4H and CH3OH column densities in this large sample. Based on this lack of correlation, a difference in line profiles between C4H and CH3OH, and previous interferometric observations of similar sources, we propose that the emission from these two molecules is spatially separated, with the CH3OH tracing gas that has been transiently heated to high (˜70-100 K) temperatures and the C4H tracing the cooler large-scale envelope where CH4 molecules have been liberated from ices. These results provide insight in the differentiation between hot corino and warm carbon-chain chemistry in embedded protostars. Based on observations with the Kitt Peak 12 m telescope telescope and the Atacama Pathfinder EXperiment (APEX) telescope. The Kitt Peak 12 m telescope is operated by the Arizona Radio Observatory (ARO), Steward Observatory, University of Arizona. APEX is a collaboration between the Max Planck Institute for Radio Astronomy, the European Southern Observatory, and the Onsala Space Observatory.

  1. CFD Growth of 3C-SiC on 4H/6H Mesas

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Trunek, Andrew J.; Spry, David J.; Powell, J. Anthony; Du, Hui; Skowronski, Marek; Huang, XianRong; Dudley, Michael

    2006-01-01

    This article describes growth and characterization of the highest quality reproducible 3C-SiC heteroepitaxial films ever reported. By properly nucleating 3C-SiC growth on top of perfectly on-axis (0001) 4H-SiC mesa surfaces completely free of atomic scale steps and extended defects, growth of 3C-SiC mesa heterofilms completely free of extended crystal defects can be achieved. In contrast, nucleation and growth of 3C-SiC mesa heterofilms on top of 4H-SiC mesas with atomic-scale steps always results in numerous observable dislocations threading through the 3C-SiC epilayer. High-resolution X-ray diffraction and transmission electron microscopy measurements indicate non-trivial in-plane lattice mismatch between the 3C and 4H layers. This mismatch is somewhat relieved in the step-free mesa case via misfit dislocations confined to the 3C/4H interfacial region without dislocations threading into the overlying 3C-SiC layer. These results indicate that the presence or absence of steps at the 3C/4H heteroepitaxial interface critically impacts the quality, defect structure, and relaxation mechanisms of single-crystal heteroepitaxial 3C-SiC films.

  2. Nutrition for winter sports.

    PubMed

    Meyer, Nanna L; Manore, Melinda M; Helle, Christine

    2011-01-01

    Winter sports are played in cold conditions on ice or snow and often at moderate to high altitude. The most important nutritional challenges for winter sport athletes exposed to environmental extremes include increased energy expenditure, accelerated muscle and liver glycogen utilization, exacerbated fluid loss, and increased iron turnover. Winter sports, however, vary greatly regarding their nutritional requirements due to variable physiological and physique characteristics, energy and substrate demands, and environmental training and competition conditions. What most winter sport athletes have in common is a relatively lean physique and high-intensity training periods, thus they require greater energy and nutrient intakes, along with adequate food and fluid before, during, and after training. Event fuelling is most challenging for cross-country skiers competing in long events, ski jumpers aiming to reduce their body weight, and those winter sport athletes incurring repeated qualification rounds and heats. These athletes need to ensure carbohydrate availability throughout competition. Finally, winter sport athletes may benefit from dietary and sport supplements; however, attention should be paid to safety and efficacy if supplementation is considered.

  3. Genetics & sport: bioethical concerns.

    PubMed

    Miah, Andy

    2012-12-01

    This paper provides an overview of the ethical issues pertaining to the use of genetic insights and techniques in sport. Initially, it considers a range of scientific findings that have stimulated debate about the ethical issues associated with genetics applied to sport. It also outlines some of the early policy responses to these discoveries from world leading sports organizations, along with knowledge about actual use of gene technologies in sport. Subsequently, it considers the challenges with distinguishing between therapeutic use and human enhancement within genetic science, which is a particularly important issue for the world of sport. Next, particular attention is given to the use of genetic information, which raises questions about the legitimacy and reliability of genetic tests, along with the potential public value of having DNA databanks to economize in health care. Finally, the ethics of gene transfer are considered, inviting questions into the values of sport and humanity. It argues that, while gene modification may seem conceptually similar to other forms of doping, the requirements upon athletes are such that new forms of enhancement become increasingly necessary to discover. Insofar as genetic science is able to create safer, more effective techniques of human modification, then it may be an appealing route through which to modify athletes to safeguard the future of elite sports as enterprises of human excellence.

  4. Sport Nutritionist: A New Sport Education Role

    ERIC Educational Resources Information Center

    Martin, Matthew R.; Zimmerman, Ryan; Ciotto, Carol

    2015-01-01

    Considering the challenges associated with adolescent obesity and the need for innovative and meaningful physical education curricula, the authors of this article decided to create a new sport education role to help students learn about the fundamental nutritional concepts and practices that contribute to a healthy and active lifestyle. The new…

  5. Doping in sports.

    PubMed

    Baron, D A; Foley, T

    2009-10-01

    Regardless of one's stance on the topic, drugs are an important issue in sports. Sports pages in newspapers around the globe routinely report on athletes at every level ofcompetition using performance enhancing substances to gain an unfair advantage over their competitors. The level of sophistication in beating drug testing, and developing "next-generation" agents continues to raise. The relative paucity of well designed research has been an additional factor impeding attempts to adequately address the problem. Very limited funds are currently available to conduct the necessary research. Without credible data, athletes are more vulnerable to the claims made by those benefiting from the sales of these compounds. Many younger fans and those dreaming of a similar future admire highly successful professional athletes. A strong, consistent statement admonishing drug use is needed. Actions speak louder than words. Every time a successful athlete is caught using PE drugs, every effort to diminish drug use is negatively impacted. The "win at all cost" and "second place is the first loser" mentality needs to be continually challenged by words and actions in youth sports at every level of competition. Finally, the war on drugs in sports needs to be a coordinated, well organized international undertaking as sports play an important role in virtually every culture. If we are to maintain the integrity of competition and protect the health of the athletes, we must dramatically increase our efforts to eliminate performance enhancing drugs as an acceptable option for any athlete. Sports science professionals and sports psychiatrists need to work with coaches, trainers, athletes, and national governing bodies to educating athletes on the effects of performance enhancing drug use. To achieve this important goal everyone involved in sports needs to be knowledgeable on the negative impact this has on all aspects of organized sports. It is a difficult challenge, but one that must be

  6. The role of small RNAs in vegetative shoot development

    PubMed Central

    Fouracre, Jim P.; Poethig, R. Scott

    2016-01-01

    Shoot development consists of the production of lateral organs in predictable spatial and temporal patterns at the shoot apex. To properly integrate such programs of growth across different cell and tissue types, plants require highly complex and robust genetic networks. Over the last twenty years, the roles of small, non-coding RNAs (sRNAs) in these networks have become increasingly apparent, not least in vegetative shoot growth. In this review, we describe recent progress in understanding the contribution of sRNAs to the regulation of vegetative shoot growth, and outline persisting experimental limitations in the field. PMID:26745378

  7. Promotion of sink activity of developing rose shoots by light.

    PubMed

    Mor, Y; Halevy, A H

    1980-11-01

    Holding young rose shoots (Rosa hybrida cv. Marimba) in darkness while the rest of the plant was in light reduced the amount of (14)C assimilates recovered from the darkened shoot by half. Relative specific activity of the shoot tip grown in light was 13.5 times greater than that of the darkened one. The flower bud at the shoot tip degenerated in darkness and died. Shoots 2 to 3 centimeters long, after flower initiation, were most sensitive to the dark treatment. The degeneration is a gradual and reversible process in the first 8 days of darkness, followed by irreversible damage and atrophy. Darkening enhanced the ability of the young leaves to compete for the available assimilates over that of the darkened shoot tip. The enhancement of the mobilizing ability of the shoot tip by light is independent of photosynthesis since spraying with 3-(3,4-dichlorophenyl)-1,1-dimethylurea or holding shoots in a CO(2)-free atmosphere did not diminish the promoting effect of light on flower bud development or assimilate import. The possibility that light exerts its effect by photoproduction of ATP was also excluded inasmuch as no differences were found in ATP levels of shoot tips held in darkness and those held in light.

  8. Aggression and sport.

    PubMed

    Burton, Robert W

    2005-10-01

    Viewing aggression in its healthy form, in contrast to its extreme and inappropriate versions, and sport as a health-promoting exercise in psychological development and maturation may allow participants and spectators alike to retain an interest in aggression and sport and derive further enjoyment from them. In addition, it will benefit all involved with sport to have a broader understanding of human aggression. Physicians, mental health professionals, and other health care providers can be influential in this process, and should be willing to get involved and speak out when issues and problems arise.

  9. Athletic pubalgia (sports hernia).

    PubMed

    Litwin, Demetrius E M; Sneider, Erica B; McEnaney, Patrick M; Busconi, Brian D

    2011-04-01

    Athletic pubalgia or sports hernia is a syndrome of chronic lower abdomen and groin pain that may occur in athletes and nonathletes. Because the differential diagnosis of chronic lower abdomen and groin pain is so broad, only a small number of patients with chronic lower abdomen and groin pain fulfill the diagnostic criteria of athletic pubalgia (sports hernia). The literature published to date regarding the cause, pathogenesis, diagnosis, and treatment of sports hernias is confusing. This article summarizes the current information and our present approach to this chronic lower abdomen and groin pain syndrome.

  10. Synthesis, antifungal activity and docking study of 2-amino-4H-benzochromene-3-carbonitrile derivatives

    NASA Astrophysics Data System (ADS)

    Mirjalili, BiBi Fatemeh; Zamani, Leila; Zomorodian, Kamiar; Khabnadideh, Soghra; Haghighijoo, Zahra; Malakotikhah, Zahra; Ayatollahi Mousavi, Seyyed Amin; Khojasteh, Shaghayegh

    2016-07-01

    Pathogenic fungi are associated with diseases ranging from simple dermatosis to life-threatening infections, particularly in immunocompromised patients. During the past two decades, resistance to established antifungal drugs has increased dramatically and has made it crucial to identify novel antimicrobial compounds. Here, we selected 12 new compounds of 2-amino-4H-benzochromene-3-carbonitrile drivetives (C1-C12) for synthesis by using nano-TiCl4.SiO2 as efficient and green catalyst, then nine of synthetic compounds were evaluated against different species of fungi, positive gram and negative gram of bacteria. Standard and clinical strains of antibiotics sensitive and resistant fungi and bacteria were cultured in appropriate media. Biological activity of the 2-amino-4H-benzochromene-3-carbonitrile derivatives against fungi and bacteries were estimated by the broth micro-dilution method as recommended by clinical and laboratory standard institute (CLSI). In addition minimal fangicidal and bactericial concenteration of the compounds were also determined. Considering our results showed that compound 2-amino-4-(4-methyl benzoate)-4H-benzo[f]chromen-3-carbonitrile (C9) had the most antifungal activity against Aspergillus clavatus, Candida glabarata, Candida dubliniensis, Candida albicans and Candida tropicalis at concentrations ranging from 8 to ≤128 μg/mL. Also compounds 2-amino-4-(3,4-dimethoxyphenyl)-4H-benzo[f]chromen-3-carbonitrile (C4) and 2-amino-4-(4-isopropylphenyl)-4H-benzo[f]chromen-3-carbonitrile (C3) had significant inhibitory activities against Epidermophyton floccosum following 2-amino-4-(4-methylbenzoate)-4H-benzo[f]chromen-3-carbonitrile (C9), respectively. Docking simulation was performed to insert compounds C3, C4 and C9 in to CYP51 active site to determine the probable binding model.

  11. Adult volunteerism in Pennsylvania 4-H natural resources programs for youth

    NASA Astrophysics Data System (ADS)

    Smith, Sanford Sherrick

    2001-07-01

    Pennsylvania's 4-H Youth Development Program relies on adult volunteers to reach youth with educational information and opportunities. Finding adults willing to do this volunteer work is challenging. This study looks at the current status of adult volunteerism with natural resources 4-H projects, and seeks to understand potential volunteers. The literature has much to offer in regards to general volunteer trends, management, motivations, and task preferences; however, few studies focus on volunteers in natural resources or environmental education. A telephone survey conducted with county 4-H agents revealed that only 3.2% of Pennsylvania's 4-H volunteers work with natural resources projects in 56 out of 67 counties, and that very few volunteers have any formal background in natural resources. Semi-structured interviews with 41 adult volunteers currently working with natural resources projects explored volunteer demographics, history, program design preferences, and ideas for seeking more volunteers. Findings from the telephone survey and the semi-structured interviews were used to generate a mail survey with large, random samples from three population groups: (1) 4-H Volunteers, (2) 4-H Parents, and (3) Natural Resources Professionals. Confidence with youth and subject matter, and adult willingness to volunteer was explored for each of the groups in relation to background, demographic characteristics, motivational needs, past and present volunteer activity, personal interests, and program design importance. Natural resources subject matter confidence was shown to be the most significant variable determining willingness to volunteer for all three groups. The variables that contributed to subject matter and youth confidence varied for each population. Key variables effecting willingness to volunteer included outdoor activity level, personal interest in natural resources, the need to fulfill feelings of social responsibility, and confidence with youth. Program design

  12. Cathodoluminescence Study of the Properties of Stacking Faults in 4H-SiC Homoepitaxial Layers

    DTIC Science & Technology

    2009-01-01

    Cathodoluminescence study of the properties of stacking faults in 4H- SiC homoepitaxial layers Serguei I. Maximenko,1,a Jaime A. Freitas, Jr.,1 Paul...2009 In-grown stacking faults in n-type 4H- SiC epitaxial layers have been investigated by real-color cathodoluminescence imaging and spectroscopy...carried out at room and liquid helium temperatures. Stacking faults with 8H stacking order were observed, as well as double layer and multilayer 3C- SiC

  13. Transition metal swift heavy ion implantation on 4H-SiC

    NASA Astrophysics Data System (ADS)

    Ali, A. Ashraf; Kumar, J.; Ramakrishnan, V.; Asokan, K.

    2016-03-01

    This work reports on the realization of Quantum Ring (QR) and Quantum Dot (QD) like structures on 4H-SiC through SHI implantation and on their Raman studies. 4H-SiC is SHI implanted with Transition Metal (TM) Ni ion at different fluences. It is observed that a vibrational mode emerges as the result of Ni ion implantation. The E2 (TO) and the A1 (LO) are suppressed as the fluence increases. In this paper Raman and AFM studies have been performed at room temperature and the queer anomalies are addressed so new devices can be fabricated.

  14. Electrical properties of extended defects in 4H-SiC investigated by photoinduced current measurements

    NASA Astrophysics Data System (ADS)

    Privitera, Stefania M. S.; Litrico, Grazia; Camarda, Massimo; Piluso, Nicolò; La Via, Francesco

    2017-03-01

    We study the correlation between crystal quality and electrical transport in 4H-SiC by micro-photoluminescence and laser-beam-induced photocurrent measurements. A focused HeCd laser at 325 nm has been employed to simultaneously measure, with a spatial resolution of a few microns, both the photoluminescence and current–voltage characteristics of 4H-SiC Schottky diodes. We found that the laser-induced photocurrent acquired along a defect can give information on its spatial distribution in depth and that the local minority carrier lifetime and generation depend on the type of stacking fault, both decreasing for defects with deeper intragap levels.

  15. Multiple shoot regeneration and effect of sugars on growth and nitidine accumulation in shoot cultures of Toddalia asiatica

    PubMed Central

    Praveena, Chinthala; Veeresham, Ciddi

    2014-01-01

    Background: Toddalia asiatica (Rutaceae) is an important medicinal plant in traditional medicinal system of India and China. Nitidine production from callus cultures of the plant had been investigated, but in vitro multiplication and secondary metabolite production from shoot cultures is not reported. Objective: The aim of the present work is to establish protocol for in vitro multiple shoot regeneration of T. asiatica and to investigate the secondary metabolite, nitidine production from the shoot cultures. Materials and Methods: Different explants were used for shoot regeneration on MS supplemented with benzyl adenine (BA) either alone or in combination with naphthalene acetic acid (NAA) in different combinations. Effect of different sugars and different concentrations of sucrose on biomass accumulation in shoot cultures in liquid medium was investigated. For in vitro rooting, shoots culture were inoculated to half strength MS medium supplemented with different concentrations of indole butyric acid. Quantitative analysis of shoot culture extracts was done for estimation of nitidine by HPTLC. Results: Shoot cultures were successfully initiated and established from nodal and shoot tip explants on MS medium supplemented with benzyl adenine and sucrose (3% w/v). Sucrose at a concentration of 3 % w/v was found to be optimum for growth and biomass accumulation. In vitro rooting of shoots was achieved on half strength MS medium supplemented with indole butyric acid 3 mg/l. Investigation of secondary metabolite production ability of the in vitro regenerated shoot cultures revealed their ability to biosynthesize nitidine. Conclusion: Shoot cultures were established and nitidine production has been observed. PMID:25298663

  16. A Cool Sport Full of Physics

    NASA Astrophysics Data System (ADS)

    Haché, Alain

    2008-10-01

    Of all sports, ice hockey is possibly the one with the widest array of physics elements in it. The game provides many examples that can bring physics to life in the classroom. Ice hockey (or just "hockey" as many Canadians would say) sees athletes sliding on ice at high speeds and in various ways, shooting and slapping pucks, and colliding against each other. The interaction between the skate blade and the ice is a problem of great physical complexity. The question "Why is ice so slippery?" has puzzled generations of scientists and, surprisingly, clear answers have come relatively recently. There is even some optics involved in hockey: how many sports are watched behind tempered glass (or Plexiglas) windows? The optical and mechanical properties of these materials are worth a physics classroom discussion. In this paper, I will review a few topics discussed at length in my book The Physics of Hockey.1,2 Interested readers may also find additional articles on our website.3

  17. Shoot inversion-induced ethylene in Pharbitis nil induces the release of apical dominance by restricting shoot elongation

    NASA Technical Reports Server (NTRS)

    Prasad, T. K.; Cline, M. G.

    1985-01-01

    Shoot inversion induces outgrowth of the highest lateral bud (HLB) adjacent to the bend in the stem in Pharbitis nil. In order to determine whether or not ethylene produced by shoot inversion plays a direct role in promoting or inhibiting bud outgrowth, comparisons were made of endogenous levels of ethylene in the HLB and HLB node of plants with and without inverted shoots. That no changes were found suggests that the control of apical dominance does not involve the direction action of ethylene. This conclusion is further supported by evidence that the direct application of ethylene inhibitors or ethrel to inactive or induced lateral buds has no significant effect on bud outgrowth. The hypothesis that ethylene evolved during shoot inversion indirectly promotes the outgrowth of the highest lateral bud (HLB) in restricting terminal bud (TB) growth is found to be supported by the following observations: (1) the restriction of TB growth appears to occur before the beginning of HLB outgrowth; (2) the treatment of the inverted portion of the shoot with AgNO3, an inhibitor of ethylene action, dramatically eliminates both the restriction of TB growth and the promotion of HLB outgrowth which usually accompany shoot inversion; and (3) the treatment of the upper shoot of an upright plant with ethrel mimics shoot inversion by retarding upper shoot growth and inducing outgrowth of the lateral bud basipetal to the treated region.

  18. Photobiomodulation on sports injuries

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Guang; Liu, Timon C.; Jiao, Jian-Ling; Li, Cheng-Zhang; Xu, Xiao-Yang

    2003-12-01

    Sports injuries healing has long been an important field in sports medicine. The stimulatory effects of Low intensity laser (LIL) irradiation have been investigated in several medical fields, such as cultured cell response, wound healing, hormonal or neural stimulation, pain relief and others. The aim of this study was to evaluate whether LIL irradiation can accelerate sports injuries healing. Some experimental and clinical studies have shown the laser stimulation effects on soft tissues and cartilage, however, controversy still exists regarding the role of LIL when used as a therapeutic device. Summarizing the data of cell studies and animal experiments and clinic trials by using the biological information model of photobiomodulation, we conclude that LIL irradiation is a valuable treatment for superficial and localized sports injuries and that the injuries healing effects of the therapy depend on the dosage of LIL irradiation.

  19. Sports and Exercise Safety

    MedlinePlus

    ... equipment fits properly, check with a coach, gym teacher, athletic trainer, or parent to make sure you have the right size and that you're wearing it correctly. Many sporting goods stores can also help you find the right ...

  20. Eye Injuries in Sports

    MedlinePlus

    ... eye protectors. Some very-high-risk sports are boxing, wrestling and contact martial arts.What are the ... eye problems or if you have a family history of retinal problems. If so, you should be ...

  1. Preventing Children's Sports Injuries

    MedlinePlus

    ... may prescribe rest, medicines to ease inflammation, and physical therapy. When recovery is complete, your child's technique or training schedule might need to be ... and Exercise Fitness for Kids Who Don't Like Sports Dehydration ...

  2. Dealing with Sports Injuries

    MedlinePlus

    ... happen over time, usually from repetitive training , like running, overhand throwing, or serving a ball in tennis. ... injury in sports that involve a lot of running. Another reason for foot injuries is wearing the ...

  3. Eating for Sports

    MedlinePlus

    ... on the Liquids You've probably seen athletes drinking water when there is a break in the action. ... Fruit juice mixed with water is another refreshing drink. But avoid sodas, especially caffeinated ones. A sports ...

  4. Sports related ocular injuries.

    PubMed

    Mishra, Avinash; Verma, Ashok K

    2012-07-01

    Every year > 600,000 sports and recreation related eye injuries occur, out of which roughly 13,500 of these result in permanent loss of sight. Up to 90% of these sports related eye injuries are preventable by using adequate eye protection equipment. Protective eyewear is made of polycarbonate, a highly impact-resistant plastic which is now easily available as prescription and non-prescription eyewear and all players should be encouraged to use them. The medical officers by educating their patients regarding the risks of eye injuries in various sports and the confirmed benefits of using protective equipment have the potential to prevent injury to over thousands of eyes every year. The medical fraternity can also play a very important role in educating the coaches, parents, and children and thus put an end to unnecessary blindness and vision loss from sports related ocular injuries, therefore ensuring a lifetime of healthy vision.

  5. Sporting Miscues. Part Two.

    ERIC Educational Resources Information Center

    Adrian, Marlene; House, Gale

    1987-01-01

    Six common sporting miscues are examined and analyzed for their meanings and ramifications. The miscues involve accurate basketball and volleyball shots; overarm patterns; volleyball spikes; softball pitching; and basketball defense moves. (CB)

  6. Water sports injuries.

    PubMed

    Shea, K P; Folcik, M

    1989-01-01

    Water sports can be a great source of fun and fitness but can also be a source of injury. Overuse injuries are common in both the recreational and competitive athlete and in the young and old alike. Proper attention to preseason conditioning, adequate warmup, early recognition and treatment of injuries, and a common sense approach to the athletic environment should minimize time off from sports and result in maximum enjoyment and performance.

  7. Sports Hernia Treatment

    PubMed Central

    Economopoulos, Kostas J.; Milewski, Matthew D.; Hanks, John B.; Hart, Joseph M.; Diduch, David R.

    2013-01-01

    Background: The minimal repair technique for sports hernias repairs only the weak area of the posterior abdominal wall along with decompressing the genitofemoral nerve. This technique has been shown to return athletes to competition rapidly. This study compares the clinical outcomes of the minimal repair technique with the traditional modified Bassini repair. Hypothesis: Athletes undergoing the minimal repair technique for a sports hernia would return to play more rapidly compared with athletes undergoing the traditional modified Bassini repair. Methods: A retrospective study of 28 patients who underwent sports hernia repair at the authors’ institution was performed. Fourteen patients underwent the modified Bassini repair, and a second group of 14 patients underwent the minimal repair technique. The 2 groups were compared with respect to time to return to sport, return to original level of competition, and clinical outcomes. Results: Patients in the minimal repair group returned to sports at a median of 5.6 weeks (range, 4-8 weeks), which was significantly faster compared with the modified Bassini repair group, with a median return of 25.8 weeks (range, 4-112 weeks; P = 0.002). Thirteen of 14 patients in the minimal repair group returned to sports at their previous level, while 9 of 14 patients in the Bassini group were able to return to their previous level of sport (P = 0.01). Two patients in each group had recurrent groin pain. One patient in the minimal repair group underwent revision hernia surgery for recurrent pain, while 1 patient in the Bassini group underwent hip arthroscopy for symptomatic hip pain. Conclusion: The minimal repair technique allows athletes with sports hernias to return to play faster than patients treated with the modified Bassini. PMID:24427419

  8. Doing sexuality in sport.

    PubMed

    Eng, Heidi

    2008-01-01

    Based on interviews with Norwegian athletes living as lesbians, gays and bisexuals, this article investigates the possible subversive effect of queer visibility in sport. While female athletes living as lesbians sometimes create queer alternative spaces within mainstream sport contexts, male athletes acting openly as homosexuals challenge heteronormative discourses by attempting to disrupt hegemonic beliefs about homosexual behavior. The sexual practices of both groups confirm as well as challenge the laws of heteronormativity.

  9. Caffeine and sports performance.

    PubMed

    Burke, Louise M

    2008-12-01

    Athletes are among the groups of people who are interested in the effects of caffeine on endurance and exercise capacity. Although many studies have investigated the effect of caffeine ingestion on exercise, not all are suited to draw conclusions regarding caffeine and sports performance. Characteristics of studies that can better explore the issues of athletes include the use of well-trained subjects, conditions that reflect actual practices in sport, and exercise protocols that simulate real-life events. There is a scarcity of field-based studies and investigations involving elite performers. Researchers are encouraged to use statistical analyses that consider the magnitude of changes, and to establish whether these are meaningful to the outcome of sport. The available literature that follows such guidelines suggests that performance benefits can be seen with moderate amounts (~3 mg.kg-1 body mass) of caffeine. Furthermore, these benefits are likely to occur across a range of sports, including endurance events, stop-and-go events (e.g., team and racquet sports), and sports involving sustained high-intensity activity lasting from 1-60 min (e.g., swimming, rowing, and middle and distance running races). The direct effects on single events involving strength and power, such as lifts, throws, and sprints, are unclear. Further studies are needed to better elucidate the range of protocols (timing and amount of doses) that produce benefits and the range of sports to which these may apply. Individual responses, the politics of sport, and the effects of caffeine on other goals, such as sleep, hydration, and refuelling, also need to be considered.

  10. Maine 4-H Afterschool Academy--A Professional Development Opportunity for Out-of-School-Time Providers

    ERIC Educational Resources Information Center

    Lobley, Jennifer; Ouellette, Kristy L.

    2013-01-01

    The Maine 4-H Afterschool Academy trained 369 after-school and out of school time providers in 2011. This easy-to-adapt professional development opportunity used blended learning, a combination of in-person and Web-based opportunities. Providers successfully learned concepts and practical knowledge regarding 4-H, specifically 4-H Science. In…

  11. Drugs in sport.

    PubMed

    McGrath, J C; Cowan, D A

    2008-06-01

    This themed issue of the British Journal of Pharmacology has been compiled and edited by Ian McGrath, Regius Professor of Physiology at University of Glasgow and David Cowan, Director of the Drug Control Centre at King's College London. It contains 11 articles covering the mechanisms of action of the major groups of drugs used illicitly in sport. The articles, written by experts in how drugs work, set out where drugs can or cannot affect sporting performance, how this relates to their legitimate medicinal use, their other detrimental effects and how they can be detected. Publication coincides with Olympic year, when sport is highlighted in the public mind and much speculation is made concerning the use of drugs. The articles provide a framework of expert, accurate knowledge to inform and facilitate these debates and to help to overcome the ill-informed and dangerous anecdotal information by which sports men and women are persuaded to misuse drugs in the mistaken belief that this will improve their performance without present or future ill effects. A unique article is included by the Spedding brothers, Mike with a long career in drug discovery and Charlie, the 1984 Los Angeles Olympic Marathon Bronze Medallist and still the English National Marathon record holder. From their unique experience, they describe the insidious and unfair way that drug-assisted performance undermines the ethos of sport and endangers the vital place of sport in maintaining the health of the population.

  12. Racquet sports. The future.

    PubMed

    Woods, R B

    1995-01-01

    The future of sports medicine and the affiliated sciences is extremely promising within the world of tennis. Players and coaches have recognized the important role of science in supporting tennis training and development. The USTA has established the sport sciences as a basis for all programs and policies. The challenges for the future appear clear: 1. To promote tennis specific research that specifically addresses the training, development, and competitive needs of coaches and athletes. 2. To access sport science information generated in other countries or by other sports that maybe useful to tennis in the United States. 3. To disseminate sport science information in user-friendly language to the widest possible audience. 4. To support all classifications of tennis players with sport science information relevant to their group including all ages and skill levels. Much has been accomplished in the past 10 years to support athlete development, but the promise of the future is exciting and will require teamwork within the tennis and scientific communities by people who love tennis.

  13. 4-H Tractor Operator Program Teaches Employability Skills and Safety to Youth

    ERIC Educational Resources Information Center

    Barrett, Debra K.

    2013-01-01

    For Michigan State University Extension, the Berrien County 4-H Tractor Operator Program has provided tractor safety education to teens for over 30 years. The certification training satisfies current requirements for operation of a 20 PTO HP or greater agricultural tractor by 14- and 15-year-old youth employed on property "not" owned,…

  14. An Evaluation of the 4-H "Health Rocks" Program: Implications for Program Improvement

    ERIC Educational Resources Information Center

    Self, Carlton; Morgan, A. Christian; Fuhrman, Nicholas E.; Navarro, Maria

    2013-01-01

    The National 4-H Council developed the Health Rocks substance abuse educational program to prevent youth from engaging in risky behaviors. The program was presented in 2010 to more than 8,000 middle school youth in Georgia. A post-then-pre evaluation was conducted with youth who completed 10 hours of instruction to determine if changes in youth…

  15. Promoting the Essential Elements of 4-H Youth Development through an Experiential Learning Model

    ERIC Educational Resources Information Center

    Meyer, Shelley; Jones, Kenneth R.

    2015-01-01

    The purpose of the project reported here was to apply Experiential Learning Theory to a context involving middle and high school aged youth while assessing the four concepts (belonging, mastery, independence, and generosity) in relation to the 4-H youth development essential elements. The conclusions of the project's evaluation suggest…

  16. A Beach and Dune Community. 4-H Marine Science. Member's Guide. Activity I. MSp 1.

    ERIC Educational Resources Information Center

    Auburn Univ., AL. Cooperative Extension Service.

    The investigation in this booklet is designed to provide 4-H members with opportunities to identify common plants and animals found on beaches and sand dunes and to determine the role of the plants and animals in this community. Learners are provided with a picture of a hypothetical beach and sand dune and a list of organisms (included in the…

  17. Factors Related to Motivating Adult Somalis with Refugee Status to Volunteer for 4-H

    ERIC Educational Resources Information Center

    Mason, Mitchell D.; Ouellette, Kristy L.

    2016-01-01

    Focus group interviews were held with adult Somali immigrants to assess their likelihood of volunteering for 4-H in Maine. This qualitative study was undertaken to identify best practices for engaging the growing Somali-Mainer population as a volunteer base. Results of the study demonstrate that Somali immigrant adults are willing to volunteer for…

  18. A novel synthesis of 4H-chromen-4-ones via intramolecular wittig reaction

    PubMed

    Kumar; Bodas

    2000-11-30

    The acylphosphoranes formed in a sequential manner from the reaction of the silyl ester of O-acyl(aroyl)salicylic acids and (trimethylsilyl)methylenetriphenylphosphorane undergo intramolecular Wittig cyclization on the ester carbonyl to afford the 4H-chromen-4-ones in good to excellent yields.

  19. 4-H Horticulture Project Activity Guides. Leader's Guide and Units 1-3.

    ERIC Educational Resources Information Center

    Illinois Univ., Urbana. Cooperative Extension Service.

    This document, concerning the 4-H horticulture project, includes a leader's guide and three youth activity guides. The leader's guide can be used to plan group project meetings that are both fun and educational. Activities can be adapted to various age groups. The leader's guide includes basic information for growing plants indoors and outdoors,…

  20. Bio-Security Proficiencies Project for Beginning Producers in 4-H

    ERIC Educational Resources Information Center

    Smith, Martin H.; Meehan, Cheryl L.; Borba, John A.

    2014-01-01

    Improving bio-security practices among 4-H members who raise and show project animals is important. Bio-security measures can reduce the risk of disease spread and mitigate potential health and economic risks of disease outbreaks involving animal and zoonotic pathogens. Survey data provided statistical evidence that the Bio-Security Proficiencies…

  1. N-[4-(Dimethyl-amino)-benzyl-idene]-4H-1,2,4-triazol-4-amine.

    PubMed

    Zhou, Hui-Liang; Zhang, Xiao-Min

    2012-05-01

    The title compound, C(11)H(13)N(5), is a Schiff base synthesized by the reaction of 4-amino-4H-1,2,4-triazole and 4-(dimethyl-amino)-benzaldehyde. The dihedral angle between the benzene and triazole rings is 43.09 (11)°. The crystal structure displays weak C-H⋯N inter-actions.

  2. Temperature Dependence of Attenuation of Coplanar Waveguide on 4H High Resistivity SIC Through 540C

    NASA Technical Reports Server (NTRS)

    Ponchak, G. E.; Schwartz, Z.; Alterovitz, S. A.; Downey, A. N.; Freeman, J. C.

    2003-01-01

    For the first time, the temperature and frequency dependence of the attenuation of a Coplanar Waveguide (CPW) on 4H, High Resistivity Sic substrate is reported. The low frequency attenuation increases by 2 dB/cm at 500 C and the high frequency attenuation increases by 3.3 dB/cm at 500 C compared to room temperature.

  3. 4-H Chickquest: Connecting Agri-Science with STEM Standards in Urban Schools

    ERIC Educational Resources Information Center

    Horton, Robert L.; Krieger, Jackie; Halasa, Katrina

    2013-01-01

    While young students are more capable of scientific inquiry than previously believed, elementary school teachers are often inexperienced in and lack confidence with teaching science. ChickQuest is a 4-H-created embryology curriculum for third-graders that meets Ohio state science standards, teaches STEM skills, and promotes ongoing interaction…

  4. Children and their 4-H animal projects: How children use science in agricultural activity

    NASA Astrophysics Data System (ADS)

    Emo, Kenneth Roy

    Many children are introduced to science through informal educational programs. 4-H, an educational youth program, has a history of introducing scientific practices into agriculture. The purpose of this ethnographically-driven case study is to examine how science informs the actions of children raising market animals in a 4-H project. For two years the researcher collected data on 4-H children with market animal projects. Observations, interviews, and artifacts gathered are interpreted using the framework of activity theory. This study provides evidence for how the context of an activity system influences individual actions. Rules developed by the organization guide the actions of children to incorporate physical and psychological tools of science into their project to achieve the object: producing animals of proper weight and quality to be competitive in the county fair. Children learn the necessary actions from a community of practitioners through which expertise is distributed. Children's learning is demonstrated by the way their participation in their project changes with time, from receiving assistance from others to developing expertise in which they provide assistance to others. The strength of this educational experience is how children apply specific tools of science in ways that provide meaning and relevancy to their 4-H activity.

  5. Diastereoselectivity in prebiotically relevant 5(4H)-oxazolone-mediated peptide couplings.

    PubMed

    Beaufils, Damien; Danger, Grégoire; Boiteau, Laurent; Rossi, Jean-Christophe; Pascal, Robert

    2014-03-21

    A stereochemical study of a potentially prebiotic peptide-forming reaction was carried out as the first part of a systems chemistry investigation of potential paths for symmetry breaking. Substantial diastereomeric excesses result from a fast epimerization of the 5(4H)-oxazolone intermediate in aqueous solution.

  6. Community Pride: An Oregon 4-H Activity Relating to Beautification and Conservation.

    ERIC Educational Resources Information Center

    Oregon State Univ., Corvallis. Cooperative Extension Service.

    The Community Pride program is a 4-H activity in conservation and beautification. Instructions for selecting and carrying out a Community Pride activity are presented: planning, organizing, and doing the project. Suggestions for possible activities are offered, and instructions for reporting the activity to the county extension office are given.…

  7. Formation of low-temperature cirrus from H2SO4/H2O aerosol droplets.

    PubMed

    Bogdan, A; Molina, M J; Sassen, K; Kulmala, M

    2006-11-23

    We present experimental results obtained with a differential scanning calorimeter (DSC) that indicate the small ice particles in low-temperature cirrus clouds are not completely solid but rather coated with an unfrozen H2SO4/H2O overlayer. Our results provide a new look on the formation, development, and microphysical properties of low-temperature cirrus clouds.

  8. Pennsylvania Youth in Action: 4-H Community Development. Adult Leader's Guide.

    ERIC Educational Resources Information Center

    Pennsylvania State Univ., University Park. Dept. of Agricultural and Extension Education.

    Designed to assist leaders in their roles as catalysts, advisors, and resource persons for the Pennsylvania Youth in Action 4-H Community Development program, the guide provides complementary educational, craft, and recreation suggestions to enhance student workbooks for three community development activity units. The first section focuses on the…

  9. Louisiana 4-H Seeds of Service School Gardens: A Descriptive View

    ERIC Educational Resources Information Center

    Cater, Melissa; Fox, Janet; Fletcher, Bobby Jr.

    2012-01-01

    Louisiana 4-H Seeds of Service School Gardens, a K-12 Learn and Serve Grant program, provides a descriptive view of how school gardens along with classroom instruction link curriculum to outdoor classrooms. The purpose of the process evaluation was to describe curriculum implementation fidelity, reach of the gardening program to participants, use…

  10. A Historical Review of Leadership Development in the FFA and 4-H

    ERIC Educational Resources Information Center

    Hoover, Tracy S.; Scholl, Jan F.; Dunigan, Anne H.; Mamontova, Nadezhda

    2007-01-01

    FFA and 4-H are two youth-based organizations that cite leadership development as a key foundational component. The purpose of this study was to review and document the historical development of leadership events and activities in both programs. Evidence can be found of leadership development in schools, conferences, and camps. Leadership-related…

  11. Bufexamac ameliorates LPS-induced acute lung injury in mice by targeting LTA4H

    PubMed Central

    Xiao, Qiang; Dong, Ningning; Yao, Xue; Wu, Dang; Lu, Yanli; Mao, Fei; Zhu, Jin; Li, Jian; Huang, Jin; Chen, Aifang; Huang, Lu; Wang, Xuehai; Yang, Guangxiao; He, Guangyuan; Xu, Yong; Lu, Weiqiang

    2016-01-01

    Neutrophils play an important role in the occurrence and development of acute lung injury (ALI). Leukotriene B4 (LTB4), a hydrolysis product of epoxide leukotriene A4 (LTA4) catalyzed by LTA4 hydrolase (LTA4H), is one of the most potent chemoattractants for neutrophil. Bufexamac is a drug widely used as an anti-inflammatory agent on the skin, however, the mechanism of action is still not fully understood. In this study, we found bufexamac was capable of specifically inhibiting LTA4H enzymatic activity and revealed the mode of interaction of bufexamac and LTA4H using X-ray crystallography. Moreover, bufexamac significantly prevented the production of LTB4 in neutrophil and inhibited the fMLP-induced neutrophil migration through inhibition of LTA4H. Finally, bufexamac significantly attenuated lung inflammation as reflected by reduced LTB4 levels and weakened neutrophil infiltration in bronchoalveolar lavage fluid from a lipopolysaccharide-induced ALI mouse model. In summary, our study indicates that bufexamac acts as an inhibitor of LTB4 biosynthesis and may have potential clinical applications for the treatment of ALI. PMID:27126280

  12. An Occupational Analysis Comparing 4-H Youth Development Agents Serving Traditional and Non-Traditional Clientele.

    ERIC Educational Resources Information Center

    Borden, Lynne M.; Harris, William

    1998-01-01

    Six 4-H agents working with traditional clients and six with nontraditional clients participated in a DACUM (Developing a Curriculum) analysis of job tasks. They performed similar duties but the nontraditional group spent more time assessing individual members; the traditional group focused more on program management. (SK)

  13. The Value of 4-H Judging Teams--Missouri Dairy Judging Alumni Survey

    ERIC Educational Resources Information Center

    Deaver, Karla; Probert, Ted

    2016-01-01

    Former Missouri 4-H Dairy Judging Team members responded to a survey about life skills development and the value of the judging team experience. Results of the survey indicate that judging team experience was highly influential in the development of communication, public speaking, and presentation skills. Respondents also indicated that judging…

  14. Participant Comfort with and Application of Inquiry-Based Learning: Results from 4-H Volunteer Training

    ERIC Educational Resources Information Center

    Haugen, Heidi; Stevenson, Anne; Meyer, Rebecca L.

    2016-01-01

    This article explores how a one-time training designed to support learning transfer affected 4-H volunteers' comfort levels with the training content and how comfort levels, in turn, affected the volunteers' application of tools and techniques learned during the training. Results of a follow-up survey suggest that the training participants…

  15. A Partnership Model for Training Episodic Environmental Stewardship 4-H Volunteers

    ERIC Educational Resources Information Center

    Young, Jane Chin; Alexander, Janice; Smith, Martin H.

    2013-01-01

    The Marin Environmental Stewardship pilot project demonstrates the potential for a partnership model that brings together external and internal collaborators to recruit and train episodic 4-H volunteers to meet environmental education needs within a community. The clientele served by the volunteers trained through the project was at-risk, urban…

  16. Performance statistics of the FORTRAN 4 /H/ library for the IBM system/360

    NASA Technical Reports Server (NTRS)

    Clark, N. A.; Cody, W. J., Jr.; Hillstrom, K. E.; Thieleker, E. A.

    1969-01-01

    Test procedures and results for accuracy and timing tests of the basic IBM 360/50 FORTRAN 4 /H/ subroutine library are reported. The testing was undertaken to verify performance capability and as a prelude to providing some replacement routines of improved performance.

  17. National Invitational Training Conference on Working with Youth with Special Needs Through 4-H.

    ERIC Educational Resources Information Center

    Worden, Phyllis, Comp.

    A conference set up to exchange and disseminate ideas and information on the mentally retarded is presented. Specific purposes of the conference are: (1) to promote appreciation and understanding of handicapped youth--mentally retarded, and physically and visually handicapped youth, (2) to promote knowledge of on-going programs through 4-H with…

  18. The Big E (Energy). 4-H Leader's Guide [for Unit 1].

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This guide is designed for leaders of the Nebraska 4-H Energy Project. The goals of the project are to: (1) help young people understand energy problems related to life styles; (2) use energy resources carefully; (3) guide members in choosing their own energy alternatives; and (4) enjoy together the challenges and creativity of finding energy…

  19. The Big E (Energy). 4-H Leader's Guide for Units 2 & 3.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This leader's guide is designed for units 2 and 3 of the Nebraska 4-H Energy Project. The goals of the project are to: (1) help young people understand energy problems related to life styles; (2) use energy resources carefully; (3) guide members in choosing their own energy alternatives; and (4) to enjoy together the challenges and creativity of…

  20. Diffusion of Social Media among County 4-H Programs in Tennessee

    ERIC Educational Resources Information Center

    Bowen, Rebekah D.; Stephens, Carrie A.; Childers, Courtney C.; Avery, Elizabeth J.; Stripling, Christopher T.

    2013-01-01

    Over the past decade, Cooperative Extension and 4-H professionals have been faced with the decision of whether to adopt new communication technologies such as social media. Research on social media and Cooperative Extension has identified risks and barriers to adoption; however, many Cooperative Extension professionals believe that social media…

  1. The growth of sport shooting participation: What does this trend mean for conservation revenue?

    USGS Publications Warehouse

    Duda, Mark D.; Beppler, Tom; Organ, John

    2017-01-01

    Enacted in 1937, the Federal Aid in Wildlife Restoration Act – more commonly known as the Pittman-Robertson Act – is one of the oldest and most reliable sources of funding for wildlife conservation in the United States. The result of organized support form sportsmen, fish and wildlife agencies, firearms manufacturers, conservation organizations, and even garden clubs, the PR Act created an excise tax on so-called “long guns” and ammunition used by hunters, thereby establishing the first sustainable source of revenue dedicated to conservation and land management efforts throughout the country. Later, legislators amended the PR Act to include an excise tax on pistols, revolvers, bows, arrows, and other archery equipment.

  2. Sports Specialization in Young Athletes

    PubMed Central

    Jayanthi, Neeru; Pinkham, Courtney; Dugas, Lara; Patrick, Brittany; LaBella, Cynthia

    2013-01-01

    Context: Sports specialization is intense training in 1 sport while excluding others. Sports specialization in early to middle childhood has become increasingly common. While most experts agree that some degree of sports specialization is necessary to achieve elite levels, there is some debate as to whether such intense practice time must begin during early childhood and to the exclusion of other sports to maximize potential for success. There is a concern that sports specialization before adolescence may be deleterious to a young athlete. Evidence Acquisition: PubMed and OVID were searched for English-language articles from 1990 to 2011 discussing sports specialization, expert athletes, or elite versus novice athletes, including original research articles, consensus opinions, and position statements. Results: For most sports, there is no evidence that intense training and specialization before puberty are necessary to achieve elite status. Risks of early sports specialization include higher rates of injury, increased psychological stress, and quitting sports at a young age. Sports specialization occurs along a continuum. Survey tools are being developed to identify where athletes fall along the spectrum of specialization. Conclusion: Some degree of sports specialization is necessary to develop elite-level skill development. However, for most sports, such intense training in a single sport to the exclusion of others should be delayed until late adolescence to optimize success while minimizing injury, psychological stress, and burnout. PMID:24427397

  3. Giant Shoot Apical Meristems in Cacti Have Ordinary Leaf Primordia but Altered Phyllotaxy and Shoot Diameter

    PubMed Central

    MAUSETH, JAMES D.

    2004-01-01

    • Background and Aims Shoot apical meristems (SAMs) in most seed plants are quite uniform in size and zonation, and molecular genetic studies of Arabidopsis and other model plants are revealing details of SAM morphogenesis. Some cacti have SAMs much larger than those of A. thaliana and other seed plants. This study examined how SAM size affects leaf primordium (LP) size, phyllotaxy and shoot diameter. • Methods. Apices from 183 species of cacti were fixed, microtomed and studied by light microscopy. • Key Results Cactus SAM diameter varies from 93 to 2565 µm, the latter being 36 times wider than SAMs of A. thaliana and having a volume 45 thousand times larger. Phyllotaxy ranges from distichous to having 56 rows of leaves and is not restricted to Fibonacci numbers. Leaf primordium diameter ranges from 44 to 402 µm, each encompassing many more cells than do LP of other plants. Species with high phyllotaxy have smaller LP, although the correlation is weak. There is almost no correlation between SAM diameter and LP size, but SAM diameter is strongly correlated with shoot diameter, with shoots being about 189·5 times wider than SAMs. • Conclusions Presumably, genes such as SHOOT‐MERISTEMLESS, WUSCHEL and CLAVATA must control much larger volumes of SAM tissue in cacti than they do in A. thaliana, and genes such as PERIANTHIA might establish much more extensive fields of inhibition around LP. These giant SAMs should make it possible to more accurately map gene expression patterns relative to SAM zonation and LP sites. PMID:15145794

  4. The Sandy Hook Elementary School shooting as tipping point

    PubMed Central

    Shultz, James M; Muschert, Glenn W; Dingwall, Alison; Cohen, Alyssa M

    2013-01-01

    Among rampage shooting massacres, the Sandy Hook Elementary School shooting on December 14, 2012 galvanized public attention. In this Commentary we examine the features of this episode of gun violence that has sparked strong reactions and energized discourse that may ultimately lead toward constructive solutions to diminish high rates of firearm deaths and injuries in the United States. PMID:28228989

  5. Determinants of elite-level air rifle shooting performance.

    PubMed

    Ihalainen, S; Kuitunen, S; Mononen, K; Linnamo, V

    2016-03-01

    This study focused on identifying the most important factors determining performance in elite-level air rifle shooting technique. Forty international- and national-level shooters completed a simulated air rifle shooting competition series. From a total of 13 795 shots in 319 tests, shooting score and 17 aiming point trajectory variables were measured with an optoelectronic device and six postural balance variables were measured with force platform. Principal component analysis revealed six components in the air rifle shooting technique: aiming time, stability of hold, measurement time, cleanness of triggering, aiming accuracy, and timing of triggering. Multiple regression analysis identified four of those, namely stability of hold, cleanness of triggering, aiming accuracy, and timing of triggering as the most important predictors of shooting performance, accounting for 81% of the variance in shooting score. The direct effect of postural balance on performance was small, accounting for less than 1% of the variance in shooting score. Indirectly, the effect can be greater through a more stable holding ability, to which postural balance was correlated significantly (R = 0.55, P < 0.001). The results of the present study can be used in assessing athletes' technical strengths and weaknesses and in directing training programs on distinct shooting technical components.

  6. Revisiting the Virginia Tech Shootings: An Ecological Systems Analysis

    ERIC Educational Resources Information Center

    Hong, Jun Sung; Cho, Hyunkag; Lee, Alvin Shiulain

    2010-01-01

    School shooting cases since the late 1990s have prompted school officials and legislators to develop and implement programs and measures that would prevent violence in school. Despite the number of explanations by the media, politicians, organizations, and researchers about the etiology of school shootings, we are not united in our understanding…

  7. Gene expression in arabidopsis shoot tips after liquid nitrogen exposure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arabidopsis thaliana shoot tips can be successfully cryopreserved using either Plant Vitrification Solution 2 (PVS2) or Plant Vitrification Solution 3 (PVS3) as the cryoprotectant. We used this model system to identify suites of genes that were either upregulated or downregulated as shoot tips recov...

  8. Gene Expression patterns in cryogenically stored Arabidopsis thaliana shoot tips

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genes expressed in response to cryostress in plant shoot tips are not known. In this project we compared the gene expression patterns in untreated, cryoprotectant-treated, and recovering shoot tips using differential display methods. This project identified two genes that appeared to be differ...

  9. Experimental Durability Testing of 4H SiC JFET Integrated Circuit Technology at 727 C

    NASA Technical Reports Server (NTRS)

    Spry, David; Neudeck, Phil; Chen, Liangyu; Chang, Carl; Lukco, Dorothy; Beheim, Glenn M

    2016-01-01

    We have reported SiC integrated circuits (IC's) with two levels of metal interconnect that have demonstrated prolonged operation for thousands of hours at their intended peak ambient operational temperature of 500 C [1, 2]. However, it is recognized that testing of semiconductor microelectronics at temperatures above their designed operating envelope is vital to qualification. Towards this end, we previously reported operation of a 4H-SiC JFET IC ring oscillator on an initial fast thermal ramp test through 727 C [3]. However, this thermal ramp was not ended until a peak temperature of 880 C (well beyond failure) was attained. Further experiments are necessary to better understand failure mechanisms and upper temperature limit of this extreme-temperature capable 4H-SiC IC technology. Here we report on additional experimental testing of custom-packaged 4H-SiC JFET IC devices at temperatures above 500 C. In one test, the temperature was ramped and then held at 727 C, and the devices were periodically measured until electrical failure was observed. A 4H-SiC JFET on this chip electrically functioned with little change for around 25 hours at 727 C before rapid increases in device resistance caused failure. In a second test, devices from our next generation 4H-SiC JFET ICs were ramped up and then held at 700 C (which is below the maximum deposition temperature of the dielectrics). Three ring oscillators functioned for 8 hours at this temperature before degradation. In a third experiment, an alternative die attach of gold paste and package lid was used, and logic circuit operation was demonstrated for 143.5 hours at 700 C.

  10. High efficiency 4H-SiC betavoltaic power sources using tritium radioisotopes

    SciTech Connect

    Thomas, Christopher; Portnoff, Samuel; Spencer, M. G.

    2016-01-04

    Realization of an 18.6% efficient 4H-silicon carbide (4H-SiC) large area betavoltaic power source using the radioisotope tritium is reported. A 200 nm 4H-SiC P{sup +}N junction is used to collect high-energy electrons. The electron source is a titanium tritide (TiH{sup 3}{sub x}) foil, or an integrated titanium tritide region formed by the diffusion of tritium into titanium. The specific activity of the source is directly measured. Dark current measured under short circuit conditions was less than 6.1 pA/cm{sup 2}. Samples measured with an external tritium foil produced an open circuit voltage of 2.09 V, short circuit current of 75.47 nA/cm{sup 2}, fill factor of 0.86, and power efficiency of 18.6%. Samples measured with an integrated source produced power efficiencies of 12%. Simulations were done to determine the beta spectrum (modified by self absorption) exiting the source and the electron hole pair generation function in the 4H-SiC. The electron-hole pair generation function in 4H-SiC was modeled as a Gaussian distribution, and a closed form solution of the continuity equation was used to analyze the cell performance. The effective surface recombination velocity in our samples was found to be 10{sup 5}–10{sup 6 }cm/s. Our analysis demonstrated that the surface recombination dominates the performance of a tritium betavoltaic device but that using a thin P{sup +}N junction structure can mitigate some of the negative effects.

  11. Shoot Turgor Does Not Limit Shoot Growth of NaCl-Affected Wheat and Barley 1

    PubMed Central

    Termaat, Annie; Passioura, John B.; Munns, Rana

    1985-01-01

    The aim of this work was to test the hypothesis that the reduced growth rate of wheat and barley that results when the roots are exposed to NaCl is due to inadequate turgor in the expanding cells of the leaves. The hypothesis was tested by exposing plants to 100 millimolar NaCl (which reduced their growth rates by about 20%), growing them for 7 to 10 days with their roots in pressure chambers, and applying sufficient pneumatic pressure in the chambers to offset the osmotic pressure of the NaCl, namely, 0.48 megapascals. The results showed that applying the pressure had no sustained effect (relative to unpressurized controls) on growth rates, transpiration rates, or osmotic pressures of the cell sap, in either the fully expanded or currently expanding leaf tissue, of both wheat and barley. The results indicate that the applied pressure correspondingly increased turgor in the shoot although this was not directly measured. We conclude that shoot turgor alone was not regulating the growth of these NaCl-affected plants, and, after discussing other possible influences, argue that a message arising in the roots may be regulating the growth of the shoot. PMID:16664152

  12. Selected Periodicals in Sport and Physical Education.

    ERIC Educational Resources Information Center

    Crase, Darrell

    1979-01-01

    Thirty-one journals pertinent to the physical educator and to the professional in the areas of motor learning, sport philosophy, sport sociology, sport psychology, and sport medicine are listed with a general note on the scope of each. (JMF)

  13. Like the Sports, Love the Writing.

    ERIC Educational Resources Information Center

    Gordon, Ken

    1995-01-01

    Cautions that sports writing should be done out of love for both sports and the act of writing. Presents reasons for becoming a sports writer. Provides a list of do's and don'ts for sports writing. (PA)

  14. Mental illness, mass shootings, and the politics of American firearms.

    PubMed

    Metzl, Jonathan M; MacLeish, Kenneth T

    2015-02-01

    Four assumptions frequently arise in the aftermath of mass shootings in the United States: (1) that mental illness causes gun violence, (2) that psychiatric diagnosis can predict gun crime, (3) that shootings represent the deranged acts of mentally ill loners, and (4) that gun control "won't prevent" another Newtown (Connecticut school mass shooting). Each of these statements is certainly true in particular instances. Yet, as we show, notions of mental illness that emerge in relation to mass shootings frequently reflect larger cultural stereotypes and anxieties about matters such as race/ethnicity, social class, and politics. These issues become obscured when mass shootings come to stand in for all gun crime, and when "mentally ill" ceases to be a medical designation and becomes a sign of violent threat.

  15. Mental Illness, Mass Shootings, and the Politics of American Firearms

    PubMed Central

    MacLeish, Kenneth T.

    2015-01-01

    Four assumptions frequently arise in the aftermath of mass shootings in the United States: (1) that mental illness causes gun violence, (2) that psychiatric diagnosis can predict gun crime, (3) that shootings represent the deranged acts of mentally ill loners, and (4) that gun control “won’t prevent” another Newtown (Connecticut school mass shooting). Each of these statements is certainly true in particular instances. Yet, as we show, notions of mental illness that emerge in relation to mass shootings frequently reflect larger cultural stereotypes and anxieties about matters such as race/ethnicity, social class, and politics. These issues become obscured when mass shootings come to stand in for all gun crime, and when “mentally ill” ceases to be a medical designation and becomes a sign of violent threat. PMID:25496006

  16. The influence of muscle tremor on shooting performance.

    PubMed

    Lakie, Martin

    2010-03-01

    Shooting ability is compromised by involuntary movement. Some of this movement is physiological tremor. Tremor size has a demonstrable inverse correlation with shooting performance. Consequently, factors which affect tremor size should affect shooting ability. Adrenaline and local muscle warming markedly increase tremor size, whereas local muscle cooling reduces it. The physiological mechanisms behind these changes are not well understood, but they have the potential to affect shooting performance in subjects who exercise heavily and/or are exposed to extreme environments. The Olympic biathlon is an event in which vigorous physical exercise alternates with rifle shooting and it often takes place in a cold environment. The possible impact of exercise, temperature and other factors on the Olympic biathlete is considered here.

  17. Human pharmacology of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) after repeated doses taken 4 h apart Human pharmacology of MDMA after repeated doses taken 4 h apart.

    PubMed

    Farré, Magí; Tomillero, Angels; Pérez-Mañá, Clara; Yubero, Samanta; Papaseit, Esther; Roset, Pere-Nolasc; Pujadas, Mitona; Torrens, Marta; Camí, Jordi; de la Torre, Rafael

    2015-10-01

    3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a popular psychostimulant, frequently associated with multiple administrations over a short period of time. Repeated administration of MDMA in experimental settings induces tolerance and metabolic inhibition. The aim is to determine the acute pharmacological effects and pharmacokinetics resulting from two consecutive 100mg doses of MDMA separated by 4h. Ten male volunteers participated in a randomized, double-blind, crossover, placebo-controlled trial. The four conditions were placebo plus placebo, placebo plus MDMA, MDMA plus placebo, and MDMA plus MDMA. Outcome variables included pharmacological effects and pharmacokinetic parameters. After a second dose of MDMA, most effects were similar to those after a single dose, despite a doubling of MDMA concentrations (except for systolic blood pressure and reaction time). After repeated MDMA administration, a 2-fold increase was observed in MDMA plasma concentrations. For a simple dose accumulation MDMA and MDA concentrations were higher (+23.1% Cmax and +17.1% AUC for MDMA and +14.2% Cmax and +10.3% AUC for MDA) and HMMA and HMA concentrations lower (-43.3% Cmax and -39.9% AUC for HMMA and -33.2% Cmax and -35.1% AUC for HMA) than expected, probably related to MDMA metabolic autoinhibition. Although MDMA concentrations doubled after the second dose, most pharmacological effects were similar or slightly higher in comparison to the single administration, except for systolic blood pressure and reaction time which were greater than predicted. The pharmacokinetic-effects relationship suggests that when MDMA is administered at a 4h interval there exists a phenomenon of acute tolerance to its effects.

  18. Interest in sports and belief in sports superstitions.

    PubMed

    McClearn, Duane G

    2004-06-01

    51 nonathletes, students (45 women) at a medium-sized southern university, were administered a survey containing three scales: an Interest in Sports Scale, a Belief in Sports Superstitions Scale, and Tobacyk and Milford's Paranormal Belief Scale (1983). Scores on the Interest in Sports Scale were significantly correlated with scores on the Belief in Sports Superstitions Scale, which measured adherence specifically to sports superstitions, but not with scores on the Paranormal Belief Scale, which measured a wide variety of irrational beliefs. Thus, participants with high interest in sports showed a tendency to subscribe to the type of irrational belief associated specifically with sports. Scores on the Belief in Sports Superstitions Scale were positively correlated with scores on the Paranormal Belief Scale.

  19. Sport Participation vs. Sport Spectatorship: Two Modes of Leisure Behavior.

    ERIC Educational Resources Information Center

    Shamir, Boas; Ruskin, Hillel

    1984-01-01

    This article reports on a study that examined and compared sport participation during leisure time and spectatorship and interest in sport as a leisure activity. The examination concentrated on motivational structure, socialization, and relationship between modes of leisure. Differences between the two sport-related types of leisure behavior are…

  20. Sport and Society: An Introduction to Sociology of Sport.

    ERIC Educational Resources Information Center

    Ibrahim, Hilmi

    A theoretical framework for the study of sport sociology is provided in this text. It is intended for students of sport, arts and humanities, sociology, and social psychology. Sport and social organization are discussed first. Three models of societies and six theories of social organization are presented which form the basis of the eclectic…

  1. Sport Psychology: Myths in Sport Education and Physical Education

    ERIC Educational Resources Information Center

    Griffin, Joy

    2008-01-01

    From a sport and exercise psychology viewpoint, this article describes the increasing professionalization of youth sport and how many well-intentioned people are using misconceptions or myths to organize and administer youth sport programs. For example, professionalization has led to specialization and year-round training, while playing multiple…

  2. Modern sports eye injuries

    PubMed Central

    Capão Filipe, J A; Rocha-Sousa, A; Falcão-Reis, F; Castro-Correia, J

    2003-01-01

    Aims: To determine the severity and long term sequelae of eye injuries caused by modern sports that could be responsible for significant ocular trauma in the future. Methods: Prospective observational study of 24 (25 eyes) athletes with sports related ocular injuries from health clubs, war games, adventure, radical and new types of soccer, presenting to an eye emergency department between 1992 and 2002 (10 years). Results: Modern sports were responsible for 8.3% of the 288 total sports eye injuries reported. Squash (29.2%) was the most common cause, followed by paintball (20.8%) and motocross (16.6%). The most common diagnosis during the follow up period was retinal breaks (20%). 18 (75%) patients sustained a severe injury. The final visual acuity remained <20/100 in two paintball players. Conclusions: Ocular injuries resulting from modern sports are often severe. Adequate instruction of the participants in the games, proper use of eye protectors, and a routine complete ophthalmological examination after an eye trauma should be mandatory. PMID:14609827

  3. Nutrition in team sports.

    PubMed

    Mujika, Iñigo; Burke, Louise M

    2010-01-01

    Team sports are based on intermittent high-intensity activity patterns, but the exact characteristics vary between and within codes, and from one game to the next. Despite the challenge of predicting exact game demands, performance in team sports is often dependent on nutritional factors. Chronic issues include achieving ideal levels of muscle mass and body fat, and supporting the nutrient needs of the training program. Acute issues, both for training and in games, include strategies that allow the player to be well fuelled and hydrated over the duration of exercise. Each player should develop a plan of consuming fluid and carbohydrate according to the needs of their activity patterns, within the breaks that are provided in their sport. In seasonal fixtures, competition varies from a weekly game in some codes to 2-3 games over a weekend road trip in others, and a tournament fixture usually involves 1-3 days between matches. Recovery between events is a major priority, involving rehydration, refuelling and repair/adaptation activities. Some sports supplements may be of value to the team athlete. Sports drinks, gels and liquid meals may be valuable in allowing nutritional goals to be met, while caffeine, creatine and buffering agents may directly enhance performance.

  4. Cannabis in Sport

    PubMed Central

    Huestis, Marilyn A.; Mazzoni, Irene; Rabin, Olivier

    2013-01-01

    Since 2004, when the World Anti-Doping Agency assumed the responsi-bility for establishing and maintaining the list of prohibited substances and methods in sport (i.e. the Prohibited List), cannabinoids have been prohibited in all sports during competition. The basis for this prohibition can be found in the World Anti-Doping Code, which defines the three criteria used to consider banning a substance. In this context, we discuss the potential of can-nabis to enhance sports performance, the risk it poses to the athlete’s health and its violation of the spirit of sport. Although these compounds are prohibited in-competition only, we explain why the pharmacokinetics of their main psychoactive compound, Δ9-tetrahydrocannabinol, may complicate the results management of adverse analytical findings. Passive inhalation does not appear to be a plausible explanation for a positive test. Although the prohibition of cannabinoids in sports is one of the most controversial issues in anti-doping, in this review we stress the reasons behind this prohibition, with strong emphasis on the evolving knowledge of cannabinoid pharmacology. PMID:21985215

  5. Sports Reference: A Core Collection.

    ERIC Educational Resources Information Center

    Safford, Barbara Ripp

    2003-01-01

    Discusses reasons for including sports books in school library reference collections, explains why they should not be found only in public library collections, and provides six annotated bibliographies of sports books suitable for intermediate or middle school library collections. (LRW)

  6. Sport Management Survey. Employment Perspectives.

    ERIC Educational Resources Information Center

    Quain, Richard J.; Parks, Janet B.

    1986-01-01

    A survey of sport management positions was designed to determine projected vacancy rates in six sport management career areas. Respondents to the survey were also questioned regarding their awareness of college professional preparation programs. Results are presented. (MT)

  7. Sports Medicine: A Functional Definition.

    ERIC Educational Resources Information Center

    Kegerreis, Sam

    1981-01-01

    Sports medicine represents a specific body of knowledge which can be practiced as a subspecialty by numerous members of medical society. Professional and sandlot athletes are equally deserving of competent and expedient sports medical care. (JN)

  8. A new model for in situ nitrogen incorporation into 4H-SiC during epitaxy

    PubMed Central

    Ferro, Gabriel; Chaussende, Didier

    2017-01-01

    Nitrogen doping of 4H-SiC during vapor phase epitaxy is still lacking of a general model explaining the apparently contradictory trends obtained by different teams. In this paper, the evolutions of nitrogen incorporation (on both polar Si and C faces) as a function of the main growth parameters (C/Si ratio, temperature, pressure and growth rate) are reviewed and explained using a model based on surface exchanges between the gas phase and the uppermost 4H-SiC atomic layers. In this model, N incorporation is driven mainly by the transient formation of C vacancies, due to H2 etching, at the surface or near the surface. It is shown that all the growth parameters are influencing the probability of C vacancies formation in a similar manner as they do for N incorporation. The surface exchange model proposes a new framework for explaining the experimental results even beyond the commonly accepted reactor type dependency. PMID:28211528

  9. Nanocrystalline diamond films as UV-semitransparent Schottky contacts to 4H-SiC

    NASA Astrophysics Data System (ADS)

    Tadjer, Marko J.; Hobart, Karl D.; Caldwell, Joshua D.; Butler, James E.; Liu, Kendrick X.; Eddy, Charles R.; Gaskill, D. Kurt; Lew, K. K.; VanMil, Brenda L.; Myers-Ward, Rachael L.; Ancona, Mario G.; Kub, Fritz J.; Feygelson, Tatyana I.

    2007-10-01

    A heterojunction between thin films of nanocrystalline diamond (NCD) and 4H-SiC has been developed. Undoped and B-doped NCDs were deposited on both n- and p- SiC epilayers. I-V measurements on p + NCD /n- SiC indicated Schottky rectifying behavior with a turn-on voltage of around 0.2V. The current increased over eight orders of magnitude with an ideality factor of 1.17 at 30°C. Ideal energy-band diagrams suggested a possible conduction mechanism for electron transport from the SiC conduction band to either the valence band or acceptor level of the NCD film. Applications as an UV semitransparent electrical contact to 4H-SiC are discussed.

  10. A 4H Silicon Carbide Gate Buffer for Integrated Power Systems

    SciTech Connect

    Ericson, N; Frank, S; Britton, C; Marlino, L; Ryu, SH; Grider, D; Mantooth, A; Francis, M; Lamichhane, R; Mudholkar, M; Shepherd, P; Glover, M; Valle-Mayorga, J; McNutt, T; Barkley, A; Whitaker, B; Cole, Z; Passmore, B; Lostetter, A

    2014-02-01

    A gate buffer fabricated in a 2-mu m 4H silicon carbide (SiC) process is presented. The circuit is composed of an input buffer stage with a push-pull output stage, and is fabricated using enhancement mode N-channel FETs in a process optimized for SiC power switching devices. Simulation and measurement results of the fabricated gate buffer are presented and compared for operation at various voltage supply levels, with a capacitive load of 2 nF. Details of the design including layout specifics, simulation results, and directions for future improvement of this buffer are presented. In addition, plans for its incorporation into an isolated high-side/low-side gate-driver architecture, fully integrated with power switching devices in a SiC process, are briefly discussed. This letter represents the first reported MOSFET-based gate buffer fabricated in 4H SiC.

  11. Thermodynamic calculations in the system CH4-H2O and methane hydrate phase equilibria.

    PubMed

    Circone, Susan; Kirby, Stephen H; Stern, Laura A

    2006-04-27

    Using the Gibbs function of reaction, equilibrium pressure, temperature conditions for the formation of methane clathrate hydrate have been calculated from the thermodynamic properties of phases in the system CH4-H2O. The thermodynamic model accurately reproduces the published phase-equilibria data to within +/-2 K of the observed equilibrium boundaries in the range 0.08-117 MPa and 190-307 K. The model also provides an estimate of the third-law entropy of methane hydrate at 273.15 K, 0.1 MPa of 56.2 J mol(-1) K(-1) for 1/nCH4.H2O, where n is the hydrate number. Agreement between the calculated and published phase-equilibria data is optimized when the hydrate composition is fixed and independent of the pressure and temperature for the conditions modeled.

  12. A new model for in situ nitrogen incorporation into 4H-SiC during epitaxy

    NASA Astrophysics Data System (ADS)

    Ferro, Gabriel; Chaussende, Didier

    2017-02-01

    Nitrogen doping of 4H-SiC during vapor phase epitaxy is still lacking of a general model explaining the apparently contradictory trends obtained by different teams. In this paper, the evolutions of nitrogen incorporation (on both polar Si and C faces) as a function of the main growth parameters (C/Si ratio, temperature, pressure and growth rate) are reviewed and explained using a model based on surface exchanges between the gas phase and the uppermost 4H-SiC atomic layers. In this model, N incorporation is driven mainly by the transient formation of C vacancies, due to H2 etching, at the surface or near the surface. It is shown that all the growth parameters are influencing the probability of C vacancies formation in a similar manner as they do for N incorporation. The surface exchange model proposes a new framework for explaining the experimental results even beyond the commonly accepted reactor type dependency.

  13. Thermodynamic calculations in the system CH4-H2O and methane hydrate phase equilibria

    USGS Publications Warehouse

    Circone, S.; Kirby, S.H.; Stern, L.A.

    2006-01-01

    Using the Gibbs function of reaction, equilibrium pressure, temperature conditions for the formation of methane clathrate hydrate have been calculated from the thermodynamic properties of phases in the system CH4-H 2O. The thermodynamic model accurately reproduces the published phase-equilibria data to within ??2 K of the observed equilibrium boundaries in the range 0.08-117 MPa and 190-307 K. The model also provides an estimate of the third-law entropy of methane hydrate at 273.15 K, 0.1 MPa of 56.2 J mol-1 K-1 for 1/n CH4??H 2O, where n is the hydrate number. Agreement between the calculated and published phase-equilibria data is optimized when the hydrate composition is fixed and independent of the pressure and temperature for the conditions modeled. ?? 2006 American Chemical Society.

  14. Monte Carlo Simulation of Electron Transport in 4H- and 6H-SiC

    SciTech Connect

    Sun, C. C.; You, A. H.; Wong, E. K.

    2010-07-07

    The Monte Carlo (MC) simulation of electron transport properties at high electric field region in 4H- and 6H-SiC are presented. This MC model includes two non-parabolic conduction bands. Based on the material parameters, the electron scattering rates included polar optical phonon scattering, optical phonon scattering and acoustic phonon scattering are evaluated. The electron drift velocity, energy and free flight time are simulated as a function of applied electric field at an impurity concentration of 1x10{sup 18} cm{sup 3} in room temperature. The simulated drift velocity with electric field dependencies is in a good agreement with experimental results found in literature. The saturation velocities for both polytypes are close, but the scattering rates are much more pronounced for 6H-SiC. Our simulation model clearly shows complete electron transport properties in 4H- and 6H-SiC.

  15. American Medical Society for Sports Medicine recommended sports ultrasound curriculum for sports medicine fellowships.

    PubMed

    Finnoff, Jonathan T; Berkoff, David; Brennan, Fred; DiFiori, John; Hall, Mederic M; Harmon, Kimberly; Lavallee, Mark; Martin, Sean; Smith, Jay; Stovak, Mark

    2015-01-01

    The following sports ultrasound (SPORTS US) curriculum is a revision of the curriculum developed by the American Medical Society for Sports Medicine (AMSSM) in 2010. Several changes have been made to the curriculum with the primary aim of providing a pathway by which a sports medicine fellow can obtain sufficient SPORTS US training to become proficient in the core competencies of SPORTS US. The core competencies of SPORTS US are outlined in the learning objectives section of this document. The term "SPORTS US" was purposefully chosen rather than "musculoskeletal ultrasound" (MSK US) because it was recognized by the panel that the evolving field of SPORTS US encompasses non-MSK applications of ultrasound such as the FAST examination (focused assessment with sonography for trauma). Although the SPORTS US core competencies in this curriculum are all MSK in nature, they represent the minimum SPORTS US knowledge a sports medicine fellow should acquire during fellowship. However, additional training in more advanced MSK and non-MSK applications of ultrasound can be provided at the fellowship director's discretion. Completion of this SPORTS US curriculum fulfills the American Institute of Ultrasound in Medicine's (AIUM) requirements to perform an MSK US examination and the prerequisites for the American Registry for Diagnostic Medical Sonography's (ARDMS) MSK sonography certification examination.

  16. Metabolic changes associated with shoot formation in tobacco callus cultures

    SciTech Connect

    Grady, K.L.

    1982-08-01

    Callus tissue derived from Nicotiana tabacum L. stem pith parenchyma cells was grown either on medium which maintains the callus in an undifferentiated state, or on medium which induces the formation of shoots. Two complementary types of studies were performed with the goal of establishing metabolic markers for the initiation of shoot formation: one designed to characterize the flow of radioactive sucrose into various metabolic pools, and one which allowed measurement of intermediary metabolite concentrations. In the former, callus tissue was incubated in (U-/sup 14/C)sucrose for periods up to one hour, and patterns of metabolite labelling in tissue grown on shoot-forming and non-shoot-forming media were compared. In the latter studies, tissue was grown for an entire subculture period on non-shoot-forming medium labelled with (U-/sup 14/C)sucrose, then subcultured to labelled non-shoot-forming or shoot-forming media, and sampled at intervals during the first week of growth. 189 references.

  17. Plant shoots exhibit synchronized oscillatory motions

    PubMed Central

    Ciszak, Marzena; Masi, Elisa; Baluška, František; Mancuso, Stefano

    2016-01-01

    ABSTRACT In animals, the ability to move has evolved as an important means of protection from predators and for enhancing nutrient uptake. In the animal kingdom, an individual's movements may become coordinated with those of other individuals that belong to the same group, which leads, for example, to the beautiful collective patterns that are observed in flocks of birds and schools of fish or in animal migration. Land plants, however, are fixed to the ground, which limits their movement and, apparently, their interactions and collective behaviors. We show that emergent maize plants grown in a group exhibit synchronized oscillatory motions that may be in-phase or anti-phase. These oscillations occur in short bursts and appear when the leaves rupture from the coleoptile tip. The appearance of these oscillations indicates an abrupt increase in the plant growth rate, which may be associated with a sudden change in the energy uptake for photosynthesis. Our results suggest that plant shoots behave as a complex network of biological oscillators, interacting through biophysical links, e.g. chemical substances or electric signals. PMID:27829981

  18. Shooting through clothing in firearm suicides.

    PubMed

    Hejna, Petr; Safr, Miroslav

    2010-05-01

    There is a longstanding empirical rule that people who commit suicide rarely shoot through their clothing, but rather put it aside to expose the nude skin. Signs of shots through clothing have always been considered suspicious, raising presumptions of the presence of an abettor. Our report, based on a retrospective study of fatal suicidal firearm injuries from the years 1980 to 2007, points out that suicide victims only rarely remove clothing from the site of the future entry wound. The report covered 43 cases with fatal gunshot wounds in the area of the thorax, with only four persons (9%) removing the clothing present in the area of the subsequent self-inflicted wound. Defects present on the clothing of a victim cannot, therefore, be understood as an absolute criterion for disproving the possibility of suicide, and nor do they necessarily indicate an unfortunate accident or homicide. If, however, the suicide victim removes the clothing from the area of the future wound, then this is almost always an indication of suicide.

  19. Plant shoots exhibit synchronized oscillatory motions.

    PubMed

    Ciszak, Marzena; Masi, Elisa; Baluška, František; Mancuso, Stefano

    2016-01-01

    In animals, the ability to move has evolved as an important means of protection from predators and for enhancing nutrient uptake. In the animal kingdom, an individual's movements may become coordinated with those of other individuals that belong to the same group, which leads, for example, to the beautiful collective patterns that are observed in flocks of birds and schools of fish or in animal migration. Land plants, however, are fixed to the ground, which limits their movement and, apparently, their interactions and collective behaviors. We show that emergent maize plants grown in a group exhibit synchronized oscillatory motions that may be in-phase or anti-phase. These oscillations occur in short bursts and appear when the leaves rupture from the coleoptile tip. The appearance of these oscillations indicates an abrupt increase in the plant growth rate, which may be associated with a sudden change in the energy uptake for photosynthesis. Our results suggest that plant shoots behave as a complex network of biological oscillators, interacting through biophysical links, e.g. chemical substances or electric signals.

  20. 4H-silicon carbide-dielectric interface recombination analysis using free carrier absorption

    NASA Astrophysics Data System (ADS)

    Suvanam, S. S.; Gulbinas, K.; Usman, M.; Linnarson, M. K.; Martin, D. M.; Linnros, J.; Grivickas, V.; Hallén, A.

    2015-03-01

    In this paper, an alternative method to characterize the interface between 4H polytype of Silicon Carbide (4H-SiC) and passivating dielectric layers is established. The studies are made on dielectric-semiconductor test structures using Al2O3 as dielectric on 4H-SiC n-type epitaxial layers. Samples with different pre- and post-dielectric deposition preparations have been fabricated on epilayers of varying thicknesses. Effective lifetimes (τeff) of all the samples were measured by an optical pump-probe method utilizing free carrier absorption (FCA) to analyse the influence of the 4H-SiC/dielectric interface on charge carrier recombination. The relative contribution to τeff from the surfaces increases with decreasing epilayer thickness, and by analysing the data in combination with numerical modelling, it is possible to extract values of the surface recombination velocities (SRVs) for interfaces prepared in different ways. For instance, it is found that SRV for a standard cleaning procedure is 2 × 106 cm/s compared to a more elaborate RCA process, yielding a more than 50 times lower value of 3.5 × 104 cm/s. Furthermore, the density of interface traps (Dit) is extracted from capacitance-voltage (CV) measurements using the Terman method and a comparison is made between the SRV extracted from FCA measurements and Dits extracted from CV measurements on the same structures fabricated with metal contacts. It is observed that the SRV increase scales linearly with the increase in Dit. The strong qualitative correlation between FCA and CV data shows that FCA is a useful characterization technique, which can also yield more quantitative information about the charge carrier dynamics at the interface.

  1. 4-[4-(Diethyl-amino)benzyl-ideneamino]-4H-1,2,4-triazole.

    PubMed

    Pan, Jian Xin; Zhang, Ju Zhou; Chen, Qian Wang

    2008-05-03

    The title compound, C(13)H(17)N(5), is a Schiff base synthesized by the reaction of 4-amino-4H-1,2,4-triazole and 4-(diethyl-amino)benzaldehyde. The triazole ring forms a dihedral angle of 5.77 (16)° with the benzene ring. The crystal structure is stabilized by an inter-molecular C-H⋯N hydrogen bond.

  2. I-V characteristics simulation of silicon carbide Ti/4H-SiC Schottky diode

    NASA Astrophysics Data System (ADS)

    Panchenko, P.; Rybalka, S.; Malakhanov, A.; Krayushkina, E.; Radkov, A.

    2016-12-01

    The simulation of current-voltage characteristics for 4H-SiC Schottky diode with Ti Schottky contact has been carried out with used of TCAD program. Obtained current-voltage characteristics has been analyzed and compared with theoretical and experimental results. It is established that the Schottky diode parameters (forward current, ideality coefficient, Schottky barrier height, breakdown voltage) obtained in proposed model are good agreement with data for such type diodes.

  3. High Resolution Topography Analysis on Threading Edge Dislocations in 4H-SiC Epilayers

    SciTech Connect

    Kamata, I.; Nagano, M; Tsuchida, H; Chen, Y; Dudley, M

    2009-01-01

    Threading edge dislocations (TEDs) in a 4H-SiC epitaxial layer are investigated using high-resolution synchrotron topography. Six types of TED image are confirmed to correspond to the Burgers vector directions by a comparison of computer simulated images and observed topography images in crystal boundaries. Using a mapping method, a wide spatial distribution of the six types of TED is examined in a quarter section of a 2-inch wafer.

  4. Resistance of 4H-SiC Schottky barriers at high forward-current densities

    SciTech Connect

    Ivanov, P. A. Samsonova, T. P.; Il’inskaya, N. D.; Serebrennikova, O. Yu.; Kon’kov, O. I.; Potapov, A. S.

    2015-07-15

    The resistance of Schottky barriers based on 4H-SiC is experimentally determined at high forward-current densities. The measured resistance is found to be significantly higher than the resistance predicted by classical mechanisms of electron transport in Schottky contacts. An assumption concerning the crucial contribution of the tunnel-transparent intermediate oxide layer between the metal and semiconductor to the barrier resistance is proposed and partially justified.

  5. Photophysics of a ruthenium 4H-imidazole panchromatic dye in interaction with titanium dioxide.

    PubMed

    Schindler, Julian; Kupfer, Stephan; Wächtler, Maria; Guthmuller, Julien; Rau, Sven; Dietzek, Benjamin

    2015-04-07

    The photophysics of bis(4,4'-di-tert-butyl-2,2'-bipyridine-κ(2)N,N')[2-(4-carboxyphenyl)-4,5-bis(p-tolylimino-κN)imidazolato]ruthenium(II) hexafluorophosphate is investigated, both in solution and attached to a nanocrystalline TiO2 film. The studied substitution pattern of the 4H-imidazole ligand is observed to block a photoinduced structural reorganization pathway within the 4H-imidazole ligand that has been previously investigated. Protonation at the 4H-imidazole ring decreases the excited-state lifetime in solution. When the unprotonated dye is anchored to TiO2, photoinduced electron injection occurs from thermally nonrelaxed triplet metal-to-ligand charge transfer ((3)MLCT) states with a characteristic time constant of 0.5 ps and an injection efficiency of roughly 25%. Electron injection from the subsequently populated thermalized (3)MLCT state of the dye does not take place. The energy of this state seems to be lower than the conduction band edge of TiO2.

  6. Laboratory detection of the C3N an C4H free radicals

    NASA Technical Reports Server (NTRS)

    Gottlieb, C. A.; Gottlieb, E. W.; Thaddeus, P.; Kawamura, H.

    1983-01-01

    The millimeter-wave spectra of the linear carbon chain free radicals C3N and C4H, first identified in IRC + 10216 and hitherto observed only in a few astronomical sources, have been detected with a Zeeman-modulated spectrometer in laboratory glow discharges through low pressure flowing mixtures of N2 + HC3N and He + HCCH, respectively. Four successive rotational transitions between 168 and 198 GHz have been measured for C3N, and five rotational transitions between 143 and 200 GHz for C4H; each is a well-resolved spin doublet owing to the unpaired electron present in both species. Precise values for the rotational, centrifugal distortion, and spin doubling constants have been obtained, which, with hyperfine constants derived from observations of the lower rotational transitions in the astronomical source TMC 1, allow all the rotational transitions of C3N and C4H at frequencies less than 300 GHz to be calculated to an absolute accuracy exceeding 1 ppm.

  7. Combustion of CH4/H2/air mixtures in catalytic microreactors.

    PubMed

    Specchia, Stefania; Vella, Luigi D; Burelli, Sara; Saracco, Guido; Specchia, Vito

    2009-03-23

    The combustion of CH(4)/H(2)/HC mixtures in a very small space represents an alternative, innovative way to produce thermal/electrical energy. Pd/NiCrO(4) catalysts are lined on SiC monoliths via in situ solution combustion synthesis (SCS), and the monoliths are then tested by feeding CH(4), H(2), and lean CH(4)/H(2) mixtures into a lab-scale test rig at an output thermal power of 7.6 MW(th) m(-3). In all cases, the combustion temperature shifts to values lower than those observed in non-catalytic combustion. When the power density is kept constant (by adding H(2) to the gas mixture), the value of CH(4)-T(50) (the half-conversion temperature of CH(4)) decreases relative to that of pure CH(4), and the slope of the conversion curve becomes steeper. The higher the H(2) concentration is, the higher the reactivity of the mixture towards CH(4) oxidation-probably due to a higher production of H(2) reactive radicals (OH).

  8. Computational Study of Anisotropic Epitaxial Recrystallization in 4H-SiC

    SciTech Connect

    Gao, Fei; Zhang, Yanwen; Posselt, Matthias; Weber, William J.

    2008-03-26

    Two nano-sized amorphous layers were employed within a crystalline cell to study anisotropic expitaxial recrystallization using molecular dynamics (MD) methods in 4H-SiC. Both amorphous layers were created with the normal of the amorphous-crystalline (a-c) interfaces along the [0001] direction, but one with a microscopic extension long the [0001] direction, i.e. the dimension along the [-12-10] direction is much larger than that along the [-12-10] direction (Ix model), and another with a microscopic extension long the [-1010] direction (Iy model). The amorphous layer within the Ix model can be completely recrystallized at 2000 K within achievable simulation time, and the recrystallization is driven by a step-regrowth mechanism. On the other hand, the nucleation and growth of secondary ordered phases are observed at high temperatures in the Iy model. The temperature for recrystallization of the amorphous layer into high quality 4H-SiC is estimated to be below 1500 K. As compared with other models, it is found that the regrowth rates and recrystallization mechanisms strongly depend on the orientation of 4H-SiC, whereas the activation energy spectra for recrystallization processes are independent on a specific polytypic structure, with activation energies ranging from 0.8 to 1.7 eV.

  9. Demonstration of the First 4H-SiC EUV Detector with Large Detection Area

    NASA Technical Reports Server (NTRS)

    Xin, Xiaobin; Yan, Feng; Koeth, Timothy W.; Hu, Jun; Zhao, Jian H.

    2005-01-01

    Ultraviolet (UV) and Extreme Ultraviolet (EUV) detectors are very attractive in astronomy, photolithography and biochemical applications. For EUV applications, most of the semiconductor detectors based on PN or PIN structures suffer from the very short penetration depth. Most of the carries are absorbed at the surface and recombined there due to the high surface recombination before reach the depletion region, resulting very low quantum efficiency. On the other hand, for Schottky structures, the active region starts from the surface and carriers generated from the surface can be efficiently collected. 4H-Sic has a bandgap of 3.26eV and is immune to visible light background noise. Also, 4H-Sic detectors usually have very good radiation hardness and very low noise, which is very important for space applications where the signal is very weak. The E W photodiodes presented in this paper are based on Schottky structures. Platinum (Pt) and Nickel (Ni) are selected as the Schottky contact metals, which have the highest electron work functions (5.65eV and 5.15eV, respectively) among all the known metals on 4H-Sic.

  10. Incipient plasticity in 4H-SiC during quasistatic nanoindentation.

    PubMed

    Goel, Saurav; Yan, Jiwang; Luo, Xichun; Agrawal, Anupam

    2014-06-01

    Silicon carbide (SiC) is an important orthopedic material due to its inert nature and superior mechanical and tribological properties. Some of the potential applications of silicon carbide include coating for stents to enhance hemocompatibility, coating for prosthetic-bearing surfaces and uncemented joint prosthetics. This study is the first to explore nanomechanical response of single crystal 4H-SiC through quasistatic nanoindentation. Displacement controlled quasistatic nanoindentation experiments were performed on a single crystal 4H-SiC specimen using a blunt Berkovich indenter (300nm tip radius) at extremely fine indentation depths of 5nm, 10nm, 12nm, 25nm, 30nm and 50nm. Load-displacement curve obtained from the indentation experiments showed yielding or incipient plasticity in 4H-SiC typically at a shear stress of about 21GPa (~an indentation depth of 33.8nm) through a pop-in event. An interesting observation was that the residual depth of indent showed three distinct patterns: (i) positive depth hysteresis above 33nm, (ii) no depth hysteresis at 12nm, and (iii) negative depth hysteresis below 12nm. This contrasting depth hysteresis phenomenon is hypothesized to originate due to the existence of compressive residual stresses (upto 143MPa) induced in the specimen by the polishing process prior to the nanoindentation.

  11. Structure–Function Relationships in Highly Modified Shoots of Cactaceae

    PubMed Central

    MAUSETH, JAMES D.

    2006-01-01

    • Background and Aims Cacti are extremely diverse structurally and ecologically, and so modified as to be intimidating to many biologists. Yet all have the same organization as most dicots, none differs fundamentally from Arabidopsis or other model plants. This review explains cactus shoot structure, discusses relationships between structure, ecology, development and evolution, and indicates areas where research on cacti is necessary to test general theories of morphogenesis. • Scope Cactus leaves are diverse; all cacti have foliage leaves; many intermediate stages in evolutionary reduction of leaves are still present; floral shoots often have large, complex leaves whereas vegetative shoots have microscopic leaves. Spines are modified bud scales, some secrete sugar as extra-floral nectaries. Many cacti have juvenile/adult phases in which the flowering adult phase (a cephalium) differs greatly from the juvenile; in some, one side of a shoot becomes adult, all other sides continue to grow as the juvenile phase. Flowers are inverted: the exterior of a cactus ‘flower’ is a hollow vegetative shoot with internodes, nodes, leaves and spines, whereas floral organs occur inside, with petals physically above stamens. Many cacti have cortical bundles vascularizing the cortex, however broad it evolves to be, thus keeping surface tissues alive. Great width results in great weight of weak parenchymatous shoots, correlated with reduced branching. Reduced numbers of shoot apices is compensated by great increases in number of meristematic cells within individual SAMs. Ribs and tubercles allow shoots to swell without tearing during wet seasons. Shoot epidermis and cortex cells live and function for decades then convert to cork cambium. Many modifications permit water storage within cactus wood itself, adjacent to vessels. PMID:16820405

  12. Sport-related concussion.

    PubMed

    Meehan, William P; Bachur, Richard G

    2009-01-01

    Sport-related concussion is a common injury in children and adolescents. Athletes seldom report concussive symptoms, which makes the diagnosis a challenge. The management of sport-related concussion has changed significantly over the last several years. The previously used grading systems and return-to-play guidelines have been abandoned in favor of more individualized assessment and management. Neuropsychological testing is being used more frequently to assist in management. After recovery, it is recommended that an athlete's return-to-play progress in a gradual, stepwise fashion while being monitored by a health care provider. Proper assessment and management of a sport-related concussion is crucial, because repeat concussions can result in decreased neurocognitive functioning, increased symptomatology, and, at times, catastrophic outcomes.

  13. Active Citizenship through Sport Education

    ERIC Educational Resources Information Center

    O'Donovan, Toni M.; MacPhail, Ann; Kirk, David

    2010-01-01

    Sport education (SE) is an instruction model developed amid concerns about the lack of authentic, legitimate opportunities for young people to experience sport through physical education and was designed to facilitate enhanced links between experiences in physical education and those in the wider world of sport. The paper discusses how one UK…

  14. Selected Problems in Sports Safety.

    ERIC Educational Resources Information Center

    American Alliance for Health, Physical Education, and Recreation, Washington, DC.

    This publication, covering a broad spectrum of sports safety problems, is designed as a source of information for those who plan, organize, administer, or evaluate various physical education and recreational activities, athletics, or sports. In the first section, the prevention of sports injury is stressed with attention to different age groups…

  15. Race in Contemporary American Sports.

    ERIC Educational Resources Information Center

    Edwards, Harry

    1982-01-01

    Racism is seen as the major force blocking Black access to most American sports and to "thinking" and authority roles in accessible sports. The overwhelming majority of Black youths seeking sports stardom are destined to be shuttled back into the Black community as noncontributors or undercontributors. (MLW)

  16. Energy Expenditure of Sport Stacking

    ERIC Educational Resources Information Center

    Murray, Steven R.; Udermann, Brian E.; Reineke, David M.; Battista, Rebecca A.

    2009-01-01

    Sport stacking is an activity taught in many physical education programs. The activity, although very popular, has been studied minimally, and the energy expenditure for sport stacking is unknown. Therefore, the purposes of this study were to determine the energy expenditure of sport stacking in elementary school children and to compare that value…

  17. Go Figure! Mathematics through Sports.

    ERIC Educational Resources Information Center

    Farmer, Lesley S. J.

    This book brings the notions of sports and mathematics together. Educators can use sports to provide a real-life context based on student interest. Not only do students become aware of mathematical thinking, but they can be "trained" to improve their mathematical skills and habits of mind through sports-related learning experiences in math. A…

  18. The Challenge of Sports English.

    ERIC Educational Resources Information Center

    Borfitz, Deborah

    1986-01-01

    Describes a Sports English class for tenth grade athletes at Vero Beach Senior High School (Florida) in which Sports Illustrated and local newspaper's sports section are required reading to capitalize on students' interests and revive reading and writing skills. Learning activities, student attitudes, and future course adaptations are discussed.…

  19. New Perspectives In Sports Medicine

    PubMed Central

    Shephard, Roy J.

    1974-01-01

    The current status of sports medicine is reviewed, with its emphasis upon treatment of the individual, particularly the elite athlete. A plea is made for greater interest in sporting activities of the general public, with emphasis upon prevention of disease. Suggestions are advanced for future research, and an appropriate curriculum for the training of the sports physician is proposed. PMID:20469052

  20. Effects of shoot inversion on stem structure in Pharbitis nil

    NASA Technical Reports Server (NTRS)

    Prasad, T. K.; Sack, F. D.; Cline, M. G.

    1988-01-01

    The effects of shoot inversion on stem structure over 72 hr were investigated in Pharbitis nil by analyzing cell number, cell length, and the cross sectional areas of cells, tissues, and regions. An increase in stem diameter can be attributed to an increase in both cell number and cross sectional area of pith (primarily) and vascular tissue (secondarily). Qualitative observations of cell wall thickness in the light microscope did not reveal any significant effects of shoot inversion on this parameter. The inhibition of shoot elongation was accompanied by a significant decrease in cell length in the pith. The results are generally consistent with an ethylene effect on cell dimensions, especially in the pith.

  1. Recent non-chemical approaches to estimate the shooting distance.

    PubMed

    López-López, Maria; García-Ruiz, Carmen

    2014-06-01

    Shooting distance estimation offers useful information for the reconstruction of firearm related incidents. The muzzle to target distance is usually estimated by examining the bullet entrance hole and the gunshot residue pattern. To visualize the pattern the forensic analyst usually uses presumptive tests based on color chemical reactions that are applied using long and tedious proceedings. Due to the drawbacks of the chemical tests recent developments for shooting distance estimation not based on color chemical tests were described in the literature. The present review covers the approaches for shooting distance estimation published in the last 10 years considering two types of target, clothing and skin.

  2. Nitrogen incorporation and interface trap reduction in silicon dioxide/4H-silicon carbide

    NASA Astrophysics Data System (ADS)

    McDonald, Kyle

    2001-07-01

    Silicon carbide is a wide band gap semiconductor whose properties make it an ideal material for high power applications. Silicon carbide thermally oxidizes to form SiO2, which is used as a gate insulator in MOSFETs; however, MOSFETs produced from the 4H-SiC polytype exhibit much lower channel mobilities than expected. A large density of interface traps produced by carbon clusters and located near the conduction band has been proposed as the source of the poor mobility. The nitridation of the SiO2/4H-SiC interface using NO and NH3 has been shown to reduce this interface trap density and improve the channel mobility. In this work, the kinetics of nitrogen incorporation using NO and NH3 are compared, and the relationship between nitrogen content and interface trap density are discussed. The nitridation of SiO2/4H-SiC in NO at temperatures from 1050--1175°C incorporates ˜1014 cm-2 of nitrogen at the interface. Oxygen formed during the thermal decomposition of NO oxidizes the substrate and removes carbon and nitrogen from the interface. When the nitridation and oxidation reactions reach equilibrium, the nitrogen content saturates independently of temperature. The nitridation of SiO 2/4H-SiC in NH; at temperatures from 1050--1175°C incorporates ˜10 16 cm-2 uniformly throughout the oxide bulk. During nitridation, oxygen is removed from the oxide, and the stoichiometry of the film is changed significantly. The nitridation of SiO2/4H-SiC in NO reduces the interface trap density near the conduction band by a factor of 10, but the trap density remains high. The complete passivation of these particular traps occurs at a nitrogen content of ≈2.5 x 1014 cm-2 , regardless of the annealing conditions. The data are consistent with a model of the interface in which the traps near the conduction band are produced by large carbon clusters with a near-continuum of energy levels. The passivation of these traps with nitrogen then proceeds by the dissolution of these carbon clusters

  3. Sports and Child Development

    PubMed Central

    2016-01-01

    The role of curricular activities for the formation of education, health and behavioural outcomes has been widely studied. Yet, the role of extra-curricular activities has received little attention. This study analyzes the effect of participation in sports clubs—one of the most popular extra-curricular activities among children. We use alternative datasets and flexible semi-parametric estimation methods with a specific way to use the panel dimension of the data to address selection into sports. We find positive and robust effects on children’s school performance and peer relations. Crowding out of passive leisure activities can partially explain the effects. PMID:27144474

  4. Physics of ball sports

    NASA Astrophysics Data System (ADS)

    Cohen, C.; Clanet, C.

    2016-06-01

    Ball sports have been part of human history for thousands of years [1]. Nowadays, 13 of them are part of the Olympic games (badminton, basketball, beach volley, football/soccer, golf, handball, hockey, rugby, table tennis, tennis, volleyball, water polo, ice hockey). All these games differ by launcher (hand, club, racket, bat), ball (size, shape and mass), pitch size and number of players. These differences induce different ball velocities. Apart from the velocities and the way to maximize them, we discuss in this article the ball trajectories and their impact on the size of sports fields.

  5. Sports and Child Development.

    PubMed

    Felfe, Christina; Lechner, Michael; Steinmayr, Andreas

    2016-01-01

    The role of curricular activities for the formation of education, health and behavioural outcomes has been widely studied. Yet, the role of extra-curricular activities has received little attention. This study analyzes the effect of participation in sports clubs-one of the most popular extra-curricular activities among children. We use alternative datasets and flexible semi-parametric estimation methods with a specific way to use the panel dimension of the data to address selection into sports. We find positive and robust effects on children's school performance and peer relations. Crowding out of passive leisure activities can partially explain the effects.

  6. A theoretical study on the reaction mechanism of O2 with C4H9• radical.

    PubMed

    Du, Hong-chen; Gong, Xue-dong

    2012-05-01

    Ab initio calculations have been performed using the complete basis set model (CBS-QB3) to study the reaction mechanism of butane radical (C(4)H(9)•) with oxygen (O(2)). On the calculated potential energy surface, the addition of O(2) to C(4)H(9)• forms three intermediates barrierlessly, which can undergo subsequent isomerization or decomposition reaction leading to various products: HOO• + C(4)H(8), C(2)H(5)• + CH(2)CHOOH, OH• + C(3)H(7)CHO, OH• + cycle-C(4)H(8)O, CH(3)• + CH(3)CHCHOOH, CH(2)OOH• + C(3)H(6). Five pathways are supposed in this study. After taking into account the reaction barrier and enthalpy, the most possible reaction pathway is C(4)H(9)• + O(2) → IM1 → TS5 → IM3 → TS6 → IM4 → TS7 → OH• + cycle-C(4)H(8)O.

  7. Mapping and modeling three dimensional lead contamination in the wetland sediments of a former trap-shooting range.

    PubMed

    Perroy, Ryan L; Belby, Colin S; Mertens, Cody J

    2014-07-15

    Legacy lead (Pb) contamination from sport shooting activities is a well-known hazard. Assessing the risk this contamination presents to the environment and public health requires a detailed understanding of its spatial distribution, yet our knowledge in this area is limited, especially for wetland shooting ranges. In this study, we analyzed 1351 sediment samples from 456 surficial (0-5 cm) locations and 38 sediment cores (0.3 to 0.9 m) to quantify the three dimensional spatial distribution of Pb contamination in an urban wetland at the site of a former trap shooting range located in southwestern Wisconsin, USA. Non-destructive X-ray images of the sediment cores were used to quantify Pb shot abundance and burial depth. Surficial and core sediment samples were processed and analyzed for total Pb content via X-ray fluorescence (XRF) analysis. X-ray and XRF results were interpolated to create a three-dimensional model of Pb shot density and sediment concentration across the study area. Over 31,000 m(3) of sediment surpassed the US Environmental Protection Agency's contamination threshold of 400mg/kg Pb, with a maximum calibrated value of 26,700 mg/kg Pb occurring near the center of the expected shot fallout zone. Shot densities of >50,000 pellets/m(2) were found in the shot fallout zone, primarily 10-30 cm below the sediment surface. X-ray image analysis and XRF analysis of sediment cores provide an accurate and inexpensive technique for rapidly mapping Pb contamination associated with gun clubs and hunting; these findings will benefit environmental contamination studies and remediation efforts at active and abandoned shooting ranges worldwide.

  8. Unusual attempted suicide by shooting through heart.

    PubMed

    Kadis, P; Pogorevc, L; Sipek, M; Vidovic, D

    2005-01-17

    Gunshot wounds in the heart are frequent suicidal injuries, especially in men. Most of them are lethal, but some cases of survival due to immediate and proper surgical treatment are reported. However, survival without specific treatment is extremely rare. In our case, a 44-year man attempted suicide by home-made shooting device. A special 12 cm long and 2.5 mm wide needle-like missile entered his body at the left anterior part of his chest, passed through the heart and lower lobe of right lung and exited at the right side of his back. The patient was able to move normally and he also looked for medical help immediately after attempting suicide. We found large atypical-shaped entrance wound on the anterior part of the chest, which was surgically treated, and tiny pointed exit wound under the right scapula. The patient was stable from cardio-circulatory and respiratory aspects from the time of admission to discharge from the hospital. We found only minimal pericardial bleeding (up to 10 mm thick) and there was no need for surgical intervention. In the next 2 weeks the haematoma absorbed spontaneously. The gunshot injury healed without any complication. Paranoid psychosis was diagnosed by psychiatrist and this probably had been the cause of attempting suicide. We think that the favorable outcome of the proved heart gunshot injury in our patient was due to the needle-shaped low-energy missile, which caused only tiny gunshot (stab) hole in the heart. Such a heart injury caused only minimal bleeding into the pericardial sac without heart tamponade.

  9. Application of Monte Carlo simulations to improve basketball shooting strategy

    NASA Astrophysics Data System (ADS)

    Min, Byeong June

    2016-10-01

    The underlying physics of basketball shooting seems to be a straightforward example of Newtonian mechanics that can easily be traced by using numerical methods. However, a human basketball player does not make use of all the possible basketball trajectories. Instead, a basketball player will build up a database of successful shots and select the trajectory that has the greatest tolerance to the small variations of the real world. We simulate the basketball player's shooting training as a Monte Carlo sequence to build optimal shooting strategies, such as the launch speed and angle of the basketball, and whether to take a direct shot or a bank shot, as a function of the player's court position and height. The phase-space volume Ω that belongs to the successful launch velocities generated by Monte Carlo simulations is then used as the criterion to optimize a shooting strategy that incorporates not only mechanical, but also human, factors.

  10. Ray-tube integration in shooting and bouncing ray method

    NASA Technical Reports Server (NTRS)

    Lee, S. W.; Ling, H.; Chou, R.

    1988-01-01

    Based on three formulations of the Huygen's principle, explicit expressions is given for the far field contribution from a small ray tube. This expression is useful in shooting and bouncing rays for solving complex scattering problems.

  11. Connective Auxin Transport in the Shoot Facilitates Communication between Shoot Apices

    PubMed Central

    Bennett, Tom; Hines, Geneviève; van Rongen, Martin; Sawchuk, Megan G.; Scarpella, Enrico; Ljung, Karin

    2016-01-01

    The bulk polar movement of the plant signaling molecule auxin through the stem is a long-recognized but poorly understood phenomenon. Here we show that the highly polar, high conductance polar auxin transport stream (PATS) is only part of a multimodal auxin transport network in the stem. The dynamics of auxin movement through stems are inconsistent with a single polar transport regime and instead suggest widespread low conductance, less polar auxin transport in the stem, which we term connective auxin transport (CAT). The bidirectional movement of auxin between the PATS and the surrounding tissues, mediated by CAT, can explain the complex auxin transport kinetics we observe. We show that the auxin efflux carriers PIN3, PIN4, and PIN7 are major contributors to this auxin transport connectivity and that their activity is important for communication between shoot apices in the regulation of shoot branching. We propose that the PATS provides a long-range, consolidated stream of information throughout the plant, while CAT acts locally, allowing tissues to modulate and be modulated by information in the PATS. PMID:27119525

  12. Connective Auxin Transport in the Shoot Facilitates Communication between Shoot Apices.

    PubMed

    Bennett, Tom; Hines, Geneviève; van Rongen, Martin; Waldie, Tanya; Sawchuk, Megan G; Scarpella, Enrico; Ljung, Karin; Leyser, Ottoline

    2016-04-01

    The bulk polar movement of the plant signaling molecule auxin through the stem is a long-recognized but poorly understood phenomenon. Here we show that the highly polar, high conductance polar auxin transport stream (PATS) is only part of a multimodal auxin transport network in the stem. The dynamics of auxin movement through stems are inconsistent with a single polar transport regime and instead suggest widespread low conductance, less polar auxin transport in the stem, which we term connective auxin transport (CAT). The bidirectional movement of auxin between the PATS and the surrounding tissues, mediated by CAT, can explain the complex auxin transport kinetics we observe. We show that the auxin efflux carriers PIN3, PIN4, and PIN7 are major contributors to this auxin transport connectivity and that their activity is important for communication between shoot apices in the regulation of shoot branching. We propose that the PATS provides a long-range, consolidated stream of information throughout the plant, while CAT acts locally, allowing tissues to modulate and be modulated by information in the PATS.

  13. Influence of intra-shoot trophic competition on shoot development in two grapevine cultivars (Vitis vinifera).

    PubMed

    Pallas, Benoît; Louarn, Gaëtan; Christophe, Angélique; Lebon, Eric; Lecoeur, Jérémie

    2008-09-01

    The effect of trophic competition between vegetative sources and reproductive sinks on grapevine (Vitis vinifera L.) shoot development was analyzed. Two international cultivars (Grenache N and Syrah) grown in pots, which were well watered, were studied. A large range of trophic competition levels was obtained by modifying the cluster loads per plant. An analytical breakdown of the branching system was used to analyze the effects of trophic competition. Phytomer production on the primary axis and the probability and timing of axillary budburst were not affected by trophic competition. However, the duration of development and leaf production rate for secondary axes were both significantly affected. The impact of trophic competition differed within the P0-P1-P2 architectural module, locally within the shoot and between cultivars. Trophic competition reduced the organogenesis of secondary axes most strongly close to clusters, on P1-P2 phytomers and in Grenache N. Based on these results, a modeling approach simulating sink strength variation and the local effects of sink proximity would be more relevant than a model considering only development as a function of thermal time or the global distribution of available biomass.

  14. Language of sport fans: sportugese revisited.

    PubMed

    Wann, D L; Metcalf, L A; Adcock, M L; Choi, C C; Dallas, M B; Slaton, E

    1997-12-01

    In 1959, Tannenbaum and Noah reported that sports writers and readers possessed a better understanding of sport terminology than nonreaders. The current investigation extended Tannenbaum and Noah's research using current sport terms. A positive relationship between understanding sport terminology, extent of team identification, strength of sport fandom, and self-proclaimed sport knowledge was hypothesized. Scores of 57 participants confirmed the predicted pattern. Discussion concerned research examining sport terminology.

  15. Women in Sport Course.

    ERIC Educational Resources Information Center

    Campbell, Mary Ann; And Others

    1980-01-01

    The philosophy, purpose, grading procedure, and course requirements for the University of Delaware's "Women in Sports" course are set forth. A course outline is provided, along with tips and a resource materials listing for those interested in initiating similar programs. (LH)

  16. The Economics of Sports.

    ERIC Educational Resources Information Center

    Kern, William S., Ed.

    This collection of papers presents a picture of economic principles at work in the dynamic world of big-time sports. Papers were given at the 35th Annual Lecture-Seminar Series presented by the Department of Economics at Western Michigan University during the 1998-99 school year. After an "Introduction" (William S. Kern), the six papers…

  17. Physiology of sport.

    PubMed

    Maughan, Ron

    2007-07-01

    The elite athlete represents the extreme of the human gene pool, where genetic endowment is developed by an intensive training programme. Sport encompasses many different activities, calling for different physical and mental attributes. Understanding the physiology of exercise provides insights into normal physiological function.

  18. Committed Sport Event Volunteers

    ERIC Educational Resources Information Center

    Han, Keunsu; Quarterman, Jerome; Strigas, Ethan; Ha, Jaehyun; Lee, Seungbum

    2013-01-01

    The purpose of this study was to investigate the relationships among selected demographic characteristics (income, education and age), motivation and commitment of volunteers at a sporting event. Three-hundred and five questionnaires were collected from volunteers in a marathon event and analyzed using structural equation modeling (SEM). Based on…

  19. Financing the Sport Enterprise

    ERIC Educational Resources Information Center

    Sawyer, Thomas H.; Hypes, Michael G.; Hypes, Julia Ann

    2004-01-01

    This book is intended to provide students in sport management curricula and professional practitioners with the first comprehensive survey coverage of the many traditional and innovative aspects of financial management. The focus of this text is on the basis of financial management including but not limited to diversification of revenue,…

  20. Sport-Related Concussions

    ERIC Educational Resources Information Center

    Brady, Don; Brady, Flo

    2011-01-01

    Sport-related concussions (SRC) are not limited to specific age ranges, professional athletes, or gender. The primary focus of much of SRC research pertains to the assessment, management, and return to play (RTP) of the concussed athlete. This article highlights some major issues of SRC along with some controversies that presently exist within the…

  1. Talking Sport and Fitness

    ERIC Educational Resources Information Center

    Dixon-Watmough, Rebecca; Keogh, Brenda; Naylor, Stuart

    2012-01-01

    For some time the Association for Science Education (ASE) has been aware that it would be useful to have some resources available to get children talking and thinking about issues related to health, sport and fitness. Some of the questions about pulse, breathing rate and so on are pretty obvious to everyone, and there is a risk of these being…

  2. Simulation in Sport Finance

    ERIC Educational Resources Information Center

    Drayer, Joris; Rascher, Dan

    2010-01-01

    Simulations have long been used in business schools to give students experience making real-world decisions in a relatively low risk environment. The OAKLAND A'S BASEBALL BUSINESS SIMULATOR takes a traditional business simulation and applies it to the sport industry, in which sales of tangible products are replaced by sales of experiences provided…

  3. Sociology of Sport.

    ERIC Educational Resources Information Center

    Greendorfer, Susan L.

    1985-01-01

    The author describes the issues which created the schism between physical education and sociology. If the subdiscipline of sports sociology is to survive, these misunderstandings must be erased. Current investigations of relevant topics are of interest to both physical educators and coaches and could begin to bridge the gap. (MT)

  4. Sports Teams Extend Reach

    ERIC Educational Resources Information Center

    Shah, Nirvi

    2012-01-01

    Unlike traditional high school athletic teams, Unified Sports teams are designed to immerse students with intellectual disabilities in a facet of school culture that has largely eluded them. Nationwide, more than 2,000 schools in 42 states have the teams, where the ideal is for about half the athletes on each team to be students with intellectual…

  5. Sport in China.

    ERIC Educational Resources Information Center

    Knuttgen, Howard G., Ed.; And Others

    Part 1 of this book, "Evoluation and Organization of Physical Culture," examines the history and current organization of physical education and sport in the People's Republic of China. This part includes chapters on: the evolution and organization of physical culture; physical culture in China today; the organizational structure of…

  6. Cold-Weather Sports

    MedlinePlus

    ... in shape during the winter gets you physically ready for springtime activities (and wardrobes). What to Do? Winter is a great time to experiment with new sports. The trick is to find one that matches your interests and natural abilities. If ...

  7. [Sport and physical activity].

    PubMed

    Bria, S; Zeppilli, P

    2010-01-01

    A regular sport activity involves physical and psychological benefits helping to improve the quality of life at any age. This aspect is even more important in the developing age, when the sport takes on a role of training and education. In this context, instances directed to allow adolescent and young adults with heart disease to practice sports seem justified, and they're becoming more pressing since when the diagnostic and therapeutic advances, especially in cardiac surgery and in interventional hemodynamics, allow an increasing number of patients, previously allocated to physical inactivity, to lead an active lifestyle. However, we have to keep in mind that congenital heart disease population is varied, not only by the nature of the malformation, but also because in the same cardiopathy you can find subjects in "natural history" or after surgery and, between them, subjects treated with several techniques and different outcomes. This justifies the need for a close collaboration between sports doctors, cardiologists and heart surgeons, particularly in the management of the most difficult and delicate problems.

  8. Common Sports Injuries

    MedlinePlus

    ... If you play sports, you already know the benefits of getting exercise while doing something you love. But even though ... for my injury? If so, what are the benefits?ResourcesCenters for Disease ... Exercise and Fitness, Family Health, Injury Rehabilitation, Prevention and ...

  9. "Emerging" Sports for Women.

    ERIC Educational Resources Information Center

    Blum, Debra E.

    1994-01-01

    The National Collegiate Athletic Association has recently introduced nine new sports to intercollegiate athletics: team handball, archery, badminton, bowling, crew, ice hockey, squash, synchronized swimming, and water polo. The initiative is intended to encourage colleges to create more athletic opportunities for women. It sets scholarship limits…

  10. Nutrition in Children's Sports.

    ERIC Educational Resources Information Center

    Smith, Nathan J.

    Young athletes need to be aware of the importance of good nutrition to athletic performance. A basic diet plan, worked out with a physician to satisfy energy and weight needs, is essential. The best eating schedule and amount and type of food varies with different sports depending on the intensity and duration of physical activity. Weight control…

  11. Neurodegeneration and sport.

    PubMed

    Davis, Gavin A; Castellani, Rudolph J; McCrory, Paul

    2015-06-01

    The recent interest in concussion in sport has resulted in significant media focus about chronic traumatic encephalopathy (CTE), although a direct causative link(s) between concussion and CTE is not established. Typically, sport-related CTE occurs in a retired athlete with or without a history of concussion(s) who presents with a constellation of cognitive, mood, and/or behavioral symptoms and who has postmortem findings of tau deposition within the brain. There are many confounding variables, however, that can account for brain tau deposition, including genetic mutations, drugs, normal aging, environmental factors, postmortem brain processing, and toxins. To understand the roles of such factors in neurodegenerative diseases that may occur in athletes, this article reviews some neurodegenerative diseases that may present with similar findings in nonathletes. The article also reviews pathological changes identified with normal aging, and reviews the pathological findings of CTE in light of all these factors. While many of these athletes have a history of exposure to head impacts as a part of contact sport, there is insufficient evidence to establish causation between sports concussion and CTE. It is likely that many of the cases with neuropathological findings represent the normal aging process, the effects of opiate abuse, or a variant of frontotemporal lobar degeneration. Whether particular genetic causes may place athletes at greater risk of neurodegenerative disease is yet to be determined.

  12. Cryotherapy of shoot tips: novel pathogen eradication method.

    PubMed

    Wang, Qiaochun; Valkonen, Jari P T

    2009-03-01

    Cryotherapy is a novel application of plant cryopreservation techniques that allows pathogen eradication at a high frequency. It eliminates plant pathogens such as viruses, phytoplasmas and bacteria by briefly treating shoot tips in liquid nitrogen using cryopreservation protocols. Healthy plants are regenerated from the surviving pathogen-free meristematic tissue. The method facilitates treatment of large numbers of samples and is independent of shoot tip size. It has the potential to replace more traditional methods like meristem culture.

  13. Ultra-High Voltage 4H-SiC Bi-Directional Insulated Gate Bipolar Transistors

    NASA Astrophysics Data System (ADS)

    Chowdhury, Sauvik

    4H- Silicon Carbide (4H-SiC) is an attractive material for power semiconductor devices due to its large bandgap, high critical electric field and high thermal conductivity compared to Silicon (Si). For ultra-high voltage applications (BV > 10 kV), 4H-SiC Insulated Gate Bipolar Transistors (IGBTs) are favored over unipolar transistors due to lower conduction losses. With improvements in SiC materials and processing technology, promising results have been demonstrated in the area of conventional unidirectional 4H-SiC IGBTs, with breakdown voltage ratings up to 27 kV. This research presents the experimental demonstration of the world's first high voltage bi-directional power transistors in 4H-SiC. Traditionally, four (two IGBTs and two diodes) or two (two reverse blocking IGBTs) semiconductor devices are necessary to yield a bidirectional switch. With a monolithically integrated bidirectional switch as presented here, the number of semiconductor devices is reduced to only one, which results in increased reliability and reduced cost of the overall system. Additionally, by using the unique dual gate operation of BD-IGBTs, switching losses can be reduced to a small fraction of that in conventional IGBTs, resulting in increased efficiency. First, the performance limits of SiC IGBTs are calculated by using analytical methods. The performance benefits of SiC IGBTs over SiC unipolar devices and Si IGBTs are quantified. Numerical simulations are used to optimize the unit cell and edge termination structures for a 15 kV SiC BD-IGBT. The effect of different device parameters on BD-IGBT static and switching performance are quantified. Second, the process technology necessary for the fabrication of high voltage SiC BD-IGBTs is optimized. The effect of different process steps on parameters such as breakdown voltage, carrier lifetime, gate oxide reliability, SiO2-SiC interface charge density is quantified. A carrier lifetime enhancement process has been optimized for lightly doped

  14. Characteristics of schools in which fatal shootings occur.

    PubMed

    de Apodaca, Roberto Flores; Brighton, Lauren M; Perkins, Ashley N; Jackson, Kiana N; Steege, Jessica R

    2012-04-01

    School-based violence, and fatal school shootings in particular, have gained increased attention in the media and psychological literature. Most reports have focused on the characteristics of perpetrators, but there is a growing awareness that school-related factors may also influence the occurrence of fatal school shootings. The current study examined several key characteristics of all schools where random (38) and targeted (96) fatal shootings occurred in the United States between 1966 and 2009. These were compared with a group (138) of schools randomly selected to represent the population of all schools in the United States. The size of a school's enrollment, urban or suburban locale, public funding, and predominantly non-white enrollment were positively associated with fatal shootings. Universities and colleges were disproportionately associated with random shootings and high schools with targeted ones. It was proposed that characteristics of schools that allow feelings of anonymity or alienation among students may help create environmental conditions associated with fatal school shootings. Implications for future research and interventions are considered.

  15. Micropropagation of Asparagus by in vitro shoot culture.

    PubMed

    Stajner, Nataša

    2013-01-01

    Asparagus officinalis is most extensively studied species within the genus Asparagus, which is well known as garden asparagus. This species is dioecious with unisexual flowers, which means that generative propagation gives roughly equal number of male and female plants. Male plants are high yielders and preferred commercially over female plants. Tissue culture techniques could efficiently promote vegetative propagation of male plants and pave the way for efficient plant breeding.This chapter describes an efficient micropropagation protocol for developing rapid growing in vitro Asparagus shoot cultures. The source of explants, inoculation, and shoot proliferation, followed by shoot propagation, rooting, and acclimatization is described. The optimal medium for Asparagus micropropagation described in this chapter is composed of MS macro- and microelements and a combination of auxins and cytokinins. Plant growth regulators NAA, kinetin, and BA were used in various concentrations. Three different media representing the whole micropropagation protocol of Asparagus are described; medium for shoot initiation, medium for shoot multiplication, and medium for root formation. By in vitro propagation of Asparagus, root initiation is difficult, but can be promoted by adding growth retardant ancymidol which also greatly promotes shoot development and suppresses callus formation.

  16. Ferns: the missing link in shoot evolution and development

    PubMed Central

    Plackett, Andrew R. G.; Di Stilio, Verónica S.; Langdale, Jane A.

    2015-01-01

    Shoot development in land plants is a remarkably complex process that gives rise to an extreme diversity of forms. Our current understanding of shoot developmental mechanisms comes almost entirely from studies of angiosperms (flowering plants), the most recently diverged plant lineage. Shoot development in angiosperms is based around a layered multicellular apical meristem that produces lateral organs and/or secondary meristems from populations of founder cells at its periphery. In contrast, non-seed plant shoots develop from either single apical initials or from a small population of morphologically distinct apical cells. Although developmental and molecular information is becoming available for non-flowering plants, such as the model moss Physcomitrella patens, making valid comparisons between highly divergent lineages is extremely challenging. As sister group to the seed plants, the monilophytes (ferns and relatives) represent an excellent phylogenetic midpoint of comparison for unlocking the evolution of shoot developmental mechanisms, and recent technical advances have finally made transgenic analysis possible in the emerging model fern Ceratopteris richardii. This review compares and contrasts our current understanding of shoot development in different land plant lineages with the aim of highlighting the potential role that the fern C. richardii could play in shedding light on the evolution of underlying genetic regulatory mechanisms. PMID:26594222

  17. In vitro regeneration of Salix nigra from adventitious shoots.

    PubMed

    Lyyra, Satu; Lima, Amparo; Merkle, Scott A

    2006-07-01

    Black willow (Salix nigra Marsh.) is the largest and only commercially important willow species in North America. It is a candidate for phytoremediation of polluted soils because it is fast-growing and thrives on floodplains throughout eastern USA. Our objective was to develop a protocol for the in vitro regeneration of black willow plants that could serve as target material for gene transformation. Unexpanded inflorescence explants were excised from dormant buds collected from three source trees and cultured on woody plant medium (WPM) supplemented with one of: (1) 0.1 mg l(-1) thidiazuron (TDZ); (2) 0.5 mg l(-1) 6-benzoaminopurine (BAP); or (3) 1 mg l(-1) BAP. All plant growth regulator (PGR) treatments induced direct adventitious bud formation from the genotypes. The percentage of explants producing buds ranged from 20 to 92%, depending on genotype and treatment. Although most of the TDZ-treated inflorescences produced buds, these buds failed to elongate into shoots. Buds on explants treated with BAP elongated into shoots that were easily rooted in vitro and further established in potting mix in high humidity. The PGR treatments significantly affected shoot regeneration frequency (P < 0.01). The highest shoot regeneration frequency (36%) was achieved with Genotype 3 cultured on 0.5 mg l(-1) BAP. Mean number of shoots per explant varied from one to five. The ability of black willow inflorescences to produce adventitious shoots makes them potential targets for Agrobacterium-mediated transformation with heavy-metal-resistant genes for phytoremediation.

  18. Transport of rubidium and strontium in detached wheat shoots

    SciTech Connect

    Feller, U.

    1986-04-01

    Rb is easily translocated in xylem and phloem (similar to K), while Sr is mobile in the xylem but rather immobile in the phloem. Wheat shoots from the field were cut 1 week after ear emergence below or above the uppermost node and incubated for 3 days standing in flasks with 2 mM rubidium chloride + 2 mM strontium chloride. In some plants the phloem flux to the ear was interrupted by steam-girdling below the ear. Rb and Sr were analyzed in the different parts of the shoots by atomic absorption spectroscopy. The Rb content in the ear depended remarkably on the treatment: 0.139 mg/ear were detected in shoots cut below the node (A), 0.015 mg/ear in shoots cut above the node (B), 0.019 mg/ear in shoots cut below the node after removing the flag leaf spread (C) and only 0.001 mg/ear in shoots cut below the node and steam-girdled below the ear (D). The Sr content was not drastically affected by these treatments: 0.278 (a), 0.317 (b), 0.356 (C) and 0.214 (D) mg/ear. These results suggest that Rb was transferred from the xylem to the phloem and translocated mainly with the phloem stream to the ear.

  19. Genetic Mapping Reveals Broader Role of Vrn-H3 Gene in Root and Shoot Development beyond Heading in Barley

    PubMed Central

    Bungartz, Annemarie; Muzammil, Shumaila; P. Afsharyan, Nazanin; Léon, Jens; Naz, Ali Ahmad

    2016-01-01

    The aim of the present study was to dissect the genetic inheritance and interplay of root, shoot and heading attributes for a better understanding of these traits in crop production. For this, we utilized quantitative trait loci (QTL) and candidate gene analysis approach using a second filial (F2) population originated from a cross between spring cultivar Cheri and wild barley accession ICB181160. The F2 population comprising 182 plants was phenotyped for root dry weight (RDW), root volume (RV), root length (RL) and shoot dry weight (SDW), tiller number per plant (TIL) and days to heading (HEA). In parallel, this population was genotyped using polymerase chain reaction (PCR) based cleaved amplified polymorphic sequence (CAPS) markers distributed across the whole genome. Marker by trait analysis revealed 16 QTL for root and shoot traits localized on chromosomes 1H, 3H, 4H, 5H and 7H. The strongest and a common QTL effect for root, shoot and heading traits was identified on chromosome 7H at the putative region of Vrn-H3 gene. Later, we have established PCR based gene specific marker HvVrnH3 revealing polymorphism for early heading Vrn-H3 allele in Cheri and late heading allele vrn-H3 in ICB181160. Genotyping of these alleles revealed a clear co-segregation of early heading Vrn-H3 allele with lower root and shoot attributes, while late heading vrn-H3 allele with more TIL and higher root biomass suggesting a primary insight on the function of Vrn-H3 gene beyond flowering. Genetic interactions of vernalization genes Vrn-H3 with Vrn-H2 and Vrn-H1 also suggested the major role of Vrn-H3 alleles in determining root and shoot trait variations in barley. We believe, these data provide an opportunity for further research to test a precise significance of early heading on yield components and root associated sustainability in crops like barley and wheat. PMID:27442506

  20. 4H-SiC JFET Multilayer Integrated Circuit Technologies Tested Up to 1000 K

    NASA Technical Reports Server (NTRS)

    Spry, D. J.; Neudeck, P. G.; Chen, L.; Chang, C. W.; Lukco, D.; Beheim, G. M.

    2015-01-01

    Testing of semiconductor electronics at temperatures above their designed operating envelope is recognized as vital to qualification and lifetime prediction of circuits. This work describes the high temperature electrical testing of prototype 4H silicon carbide (SiC) junction field effect transistor (JFET) integrated circuits (ICs) technology implemented with multilayer interconnects; these ICs are intended for prolonged operation at temperatures up to 773K (500 C). A 50 mm diameter sapphire wafer was used in place of the standard NASA packaging for this experiment. Testing was carried out between 300K (27 C) and 1150K (877 C) with successful electrical operation of all devices observed up to 1000K (727 C).

  1. Insight into metal-enhanced oxidation using barium on 4H-SiC surfaces

    NASA Astrophysics Data System (ADS)

    Chanthaphan, Atthawut; Katsu, Yoshihito; Hosoi, Takuji; Shimura, Takayoshi; Watanabe, Heiji

    2016-12-01

    Metal-enhanced oxidation (MEO) using ultrathin Ba layers on 4H-SiC surfaces was investigated by physical and electrical characterizations. We found that while comparable oxidation rates were enhanced for Si- and C-face surfaces even at a low temperature, significant surface and interface roughness were induced by initial MEO termed the incubation period. Depth profiling revealed that although most Ba atoms aggregated on the oxide surface, a tiny amount (˜1014 cm-2) remaining at the oxide interface was responsible for the following stable MEO reaction and the reduced interface state density with the drawbacks of degraded leakage current and breakdown characteristics of SiC-MOS devices.

  2. Compensation Mechanism in High Purity Semi-Insulating 4H-SiC

    DTIC Science & Technology

    2007-01-01

    online 15 March 2007 A study of deep levels in high purity semi-insulating 4H-SiC has been made using temperature dependent Hall effect TDH , thermal and...optical admittance spectroscopies, and secondary ion mass spectrometry SIMS. Thermal activation energies from TDH varied from a low of 0.55 eV to a...high of 1.65 eV. All samples studied showed n-type conduction with the Fermi level in the upper half of the band gap. Fits of the TDH data to

  3. C4H2, HC3N and C2N2 in Titan's atmosphere

    NASA Astrophysics Data System (ADS)

    Kunde, V. G.; Aikin, A. C.; Hanel, R. A.; Jennings, D. E.; Maguire, W. C.; Samuelson, R. E.

    1981-08-01

    Voyager 1 took IR measurements of the atmosphere of Titan, and obtained an average of 346 spectra, mostly from the center of the disk. The compounds C4H2, HC3N, and C2N2 were detected in the atmosphere of Titan. The identification of two compounds containing nitrogen, in addition to HCN, provides further evidence for the abundance of free N2 on Titan. The organic compounds observed in the atmosphere of Titan are summarized in a table, which also indicates the approximate mole fraction for each compound identified previously. The observed compounds originate by reactions of methane and nitrogen radicals in a predominantly nitrogen atmosphere.

  4. Transient collector modulation of 4H-SiC BJTs during switch-on process

    NASA Astrophysics Data System (ADS)

    Yuferev, Valentin S.; Levinshtein, Michael E.; Ivanov, Pavel A.; Zhang, Jon Q.; Palmour, John W.

    2016-09-01

    Main physical features of the collector resistance modulation processes have been studied via a one-dimensional simulation for n+-p-n0-n+ 4H-SiC bipolar junction transistor. The motion dynamics of minority carriers (holes) across the n0 collector layer during the switch-on process is traced. It is demonstrated that the effective modulation of the collector resistance is only possible in the case of a rather fast transistor switch-on. A necessary condition for the fast switch-on is the large amplitude and short leading edge of the base current pulse.

  5. Orientation of the water moiety in CF4-H2O

    NASA Astrophysics Data System (ADS)

    Evangelisti, Luca; Feng, Gang; Gou, Qian; Guidetti, Gloria; Caminati, Walther

    2012-12-01

    The rotational spectrum of CF4-H217O has been investigated by pulsed jet Fourier transform microwave spectroscopy. A symmetric top effective rotational spectrum has been observed, similarly to the case of the parent species (W. Caminati, A. Maris, A. Dell'Erba, P.G. Favero, Angew. Chem. Int. Ed. 45 (2006) 6711). The experimental value of the 17O χaa quadrupole coupling constant, 0.54(1) MHz, allows to determine the average value of the angle between the C2 axis of H2O and the C⋯O line, β = 24°.

  6. Atomic oxidation of large area epitaxial graphene on 4H-SiC(0001)

    SciTech Connect

    Velez-Fort, E.; Ouerghi, A.; Silly, M. G.; Sirtti, F.; Eddrief, M.; Marangolo, M.; Shukla, A.

    2014-03-03

    Structural and electronic properties of epitaxial graphene on 4H-SiC were studied before and after an atomic oxidation process. X-ray photoemission spectroscopy indicates that oxygen penetrates into the substrate and decouples a part of the interface layer. Raman spectroscopy demonstrates the increase of defects due to the presence of oxygen. Interestingly, we observed on the near edge x-ray absorption fine structure spectra a splitting of the π* peak into two distinct resonances centered at 284.7 and 285.2 eV. This double structure smears out after the oxidation process and permits to probe the interface architecture between graphene and the substrate.

  7. Theoretical study on the reaction of C4H (X˜2Σ+) with CH3OH

    NASA Astrophysics Data System (ADS)

    Huo, Ruiping; Zhang, Xiang; Zhang, Caifeng

    2015-01-01

    The reaction mechanism of linear butadiynyl radical C4H (C1C2C3C4H) with methanol (CH3OH) was studied at the CCSD(T)/aug-cc-pVTZ//BB1K/6-311+G(2d,2p) level. Six different hydrogen abstraction channels were considered, and methyl-H and hydroxyl-H of CH3OH abstractions by C1 atom (M1 and M2) are the two predominant and competitive channels. Further analysis indicated that M1 is a hydrogen atom transfer (HAT) channel while M2 is a proton-coupled electron transfer (PCET) channel. For M1 and M2, the high-pressure rate constants in the temperature range of 100-1400 K were calculated by ICVT/SCT and TST/W methods and the changes of branching ratios with temperature under four pressures (0.1, 1.0, 10 and 100 atm) were also considered by Master equation approach.

  8. Defect Characterization of 4H-SiC Wafers for Power Electronic Device Applications.

    NASA Astrophysics Data System (ADS)

    Cicero, G.; Ferrero, S.; Cocuzza, M.; Giorgis, F.; Mandracci, P.; Ricciardi, C.; Scaltrito, L.; Pirri, C. F.; Richieri, G.; Sgorlon, C.

    2002-03-01

    Silicon carbide is a wide band gap semiconductor, interesting for its physical properties such as high breakdown field, high saturated drift velocity and high thermal conductivity, which has been intensively studied in the last years. Although the high potentiality of this material, the SiC technology shows at the moment some limitations and requires further study in order to obtain electronic devices with the same quality standards of the Si technology. Indeed, the reliability of SiC-based devices is strictly correlated to the defects present in the crystalline structure. We have focused our investigation on 4H-SiC wafers and on 4H epitaxial layers in order to determine in both the situations the different type of defects. A preliminary investigation has been performed by optical microscopy and Scanning Electron Microscopy with the aim to evidence the defect morphology on large scale. A deeper insight on the defects typology has been obtained by Atomic Force Microscopy, Profilometer technique, Micro-Raman and Micro-Photoluminescence spectroscopies. Different types of defects such as micropipes, comets, super dislocations, etch pits and so on, have been characterized finding particular physical finger-prints. This investigation is aimed at correlating the defects and the electrical properties of SiC for power electronic device applications.

  9. Microwave photoconductivity decay characterization of high-purity 4H-SiC substrates

    NASA Astrophysics Data System (ADS)

    Kumar, R. J.; Borrego, J. M.; Gutmann, R. J.; Jenny, J. R.; Malta, D. P.; Hobgood, H. McD.; Carter, C. H.

    2007-07-01

    A microwave photoconductivity decay (MPCD) technique, which probes conductivity change in wafers in response to either an above-band-gap or below-band-gap laser pulse, has been used to characterize recombination lifetime in high-purity 4H-SiC substrates produced with three different anneal processes. The above-band-gap (266nm) decay times vary from ˜10ns to tens of microseconds in the 4H-SiC substrates depending on the wafer growth parameters. Wafers produced using the three processes A (as-grown), B (annealed at 2000°C), and C (annealed at 2600°C) have decay times of 10-20ns, 50-500ns, and tens of microseconds, respectively. The differences in decay times are attributed to low, medium, and high densities of recombination centers in process C, B, and A wafers, respectively. The MPCD results correlate with other characterization results such as deep level transient spectroscopy, which also showed that the 2600°C anneal process significantly reduces defect densities, resulting in the enhanced recombination lifetimes. Modeling and one-dimensional simulations indicate a trapping center closer to the conduction band results in a longer MPCD decay transient, but such a trapping based model for the enhanced lifetimes is not compatible with the wide range of experimental characterization results described in this work, which indicate an annealing out of recombination centers at 2600°C.

  10. Schottky barrier detection devices having a 4H-SiC n-type epitaxial layer

    SciTech Connect

    Mandal, Krishna C.; Terry, J. Russell

    2016-12-06

    A detection device, along with methods of its manufacture and use, is provided. The detection device can include: a SiC substrate defining a substrate surface cut from planar to about 12.degree.; a buffer epitaxial layer on the substrate surface; a n-type epitaxial layer on the buffer epitaxial layer; and a top contact on the n-type epitaxial layer. The buffer epitaxial layer can include a n-type 4H--SiC epitaxial layer doped at a concentration of about 1.times.10.sup.15 cm.sup.-3 to about 5.times.10.sup.18 cm.sup.-3 with nitrogen, boron, aluminum, or a mixture thereof. The n-type epitaxial layer can include a n-type 4H--SiC epitaxial layer doped at a concentration of about 1.times.10.sup.13 cm.sup.-3 to about 5.times.10.sup.15 cm.sup.-3 with nitrogen. The top contact can have a thickness of about 8 nm to about 15 nm.

  11. n-ZnO/p-4H-SiC diode: Structural, electrical, and photoresponse characteristics

    SciTech Connect

    Guziewicz, M. Jung, W.

    2015-09-07

    Epitaxial n-type ZnO film has been grown, on a commercial 5 μm thick p-type 4H-SiC(00.1) Al doped epilayer, by atomic layer deposition. A full width at half maximum of the ZnO 00.2 diffraction peak rocking curve of 0.34°{sup  }± 0.02° has been measured. Diodes formed on the n-ZnO/p-4H-SiC heterostructure show rectifying behavior with a forward to reverse current ratio at the level of 10{sup 9} at ±4 V, a leakage current density of ∼6 × 10{sup −8} A/cm{sup 2}, and a low ideality factor equal to 1.17 ± 0.04. In addition, the diodes exhibit selective photoresponse with a maximum at 367 nm, and with a current increase of ∼10{sup 3} under illuminations with respect to the dark value, which makes such devices prospective candidates for ultraviolet light sensors.

  12. Exploration of Defects in 4H-SiC MOSFETs via Spin Dependent Charge Pumping

    NASA Astrophysics Data System (ADS)

    Anders, Mark; Lenahan, Patrick; Lelis, Aivars

    4H-SiC MOSFETs have great promise for use in high temperature and high voltage applications. Unfortunately, defects at the SiC/SiO2 interface reduce the performance of these devices. Previously, our group utilized electrically detected magnetic resonance (EDMR) detected via spin dependent recombination (SDR) to identify such SiC/SiO2 interface defects utilizing the bipolar amplification (BAE) biasing scheme; we observed SiC silicon vacancies, E-prime centers, and hydrogen complexed E-prime centers. All of these defects must have levels around the middle of the SiC band gap because they are effective recombination centers. We expanded our studies to include EDMR detection via spin dependent charge pumping (SDCP) at low field, X band, and K band, allowing EDMR exploration of nearly the entire 4H-SiC band gap. Perhaps the most important finding of the (nearly) full band gap measurements is the absence of the carbon dangling bond spectrum in the SDCP. Additionally, in nMOSFETs, we observe an SDCP EDMR spectrum dominated by a silicon vacancy, whereas in pMOSFETs, we also observe a strong, nearly isotropic single line spectrum with g = 2.00244 and 2.00248 when the c-axis is nearly parallel and perpendicular to the magnetic field, respectively. The results suggest that silicon vacancy centers dominate nMOSFET interfaces whereas additional defects clearly play important roles in pMOSFETs.

  13. Characterization of V-shaped defects in 4H-SiC homoepitaxial layers

    SciTech Connect

    Zhang, Lihua; Su, Dong; Kisslinger, Kim; Stach, Eric; Chung, Gil; Zhang, Jie; Thomas, Bernd; Sanchez, Edward K; Mueller, Stephan G.; Hansen, Darren; Loboda, Mark J.; Wu, Fangzhen; Wang, Huanhuan; Raghothamachar, Balaji; Dudley, Michael

    2014-12-04

    Synchrotron white beam x-ray topography images show that faint needle-like surface morphological features observed on the Si-face of 4H-SiC homoepitaxial layers using Nomarski optical microscopy are associated with V shaped stacking faults in the epilayer. KOH etching of the V shaped defect reveals small oval pits connected by a shallow line which corresponding to the surface intersections of two partial dislocations and the stacking fault connecting them. Transmission electron microscopy (TEM) specimens from regions containing the V shaped defects were prepared using focused ion beam milling, and stacking sequences of (85), (50) and (63) are observed at the faulted region with high resolution TEM. In order to study the formation mechanism of V shaped defect, low dislocation density 4H-SiC substrates were chosen for epitaxial growth, and the corresponding regions before and after epitaxy growth are compared in SWBXT images. It is found that no defects in the substrate are directly associated with the formation of the V shaped defect. Simulation results of the contrast from the two partial dislocations associated with V shaped defect in synchrotron monochromatic beam x-ray topography reveals the opposite sign nature of their Burgers vectors. Therefore, a mechanism of 2D nucleation during epitaxy growth is postulated for the formation of the V shaped defect, which requires elimination of non-sequential 1/4[0001] bilayers from the original structure to create the observed faulted stacking sequence.

  14. Characterization of V-shaped defects in 4H-SiC homoepitaxial layers

    DOE PAGES

    Zhang, Lihua; Su, Dong; Kisslinger, Kim; ...

    2014-12-04

    Synchrotron white beam x-ray topography images show that faint needle-like surface morphological features observed on the Si-face of 4H-SiC homoepitaxial layers using Nomarski optical microscopy are associated with V shaped stacking faults in the epilayer. KOH etching of the V shaped defect reveals small oval pits connected by a shallow line which corresponding to the surface intersections of two partial dislocations and the stacking fault connecting them. Transmission electron microscopy (TEM) specimens from regions containing the V shaped defects were prepared using focused ion beam milling, and stacking sequences of (85), (50) and (63) are observed at the faulted regionmore » with high resolution TEM. In order to study the formation mechanism of V shaped defect, low dislocation density 4H-SiC substrates were chosen for epitaxial growth, and the corresponding regions before and after epitaxy growth are compared in SWBXT images. It is found that no defects in the substrate are directly associated with the formation of the V shaped defect. Simulation results of the contrast from the two partial dislocations associated with V shaped defect in synchrotron monochromatic beam x-ray topography reveals the opposite sign nature of their Burgers vectors. Therefore, a mechanism of 2D nucleation during epitaxy growth is postulated for the formation of the V shaped defect, which requires elimination of non-sequential 1/4[0001] bilayers from the original structure to create the observed faulted stacking sequence.« less

  15. High-purity semi-insulating 4H-SiC for microwave device applications

    NASA Astrophysics Data System (ADS)

    Jenny, J. R.; Malta, D. P.; Müller, St G.; Powell, A. R.; Tsvetkov, V. F.; Hobgood, H. Mcd; Glass, R. C.; Carter, C. H., Jr.

    2003-05-01

    High-purity, semi-insulating (HPSI) 4H-SiC crystals with diameters up to 75 mm have been grown by the seeded sublimation technique without the intentional introduction of elemental deep-level dopants, such as vanadium. Wafers cut from these crystals exhibit homogeneous activation energies near mid gap and thermally stable semi-insulating (SI) behavior (>109 ohm-cm) throughout device processing. Secondary ion mass spectroscopy, deep-level transient spectroscopy, optical admittance spectroscopy, and electron paramagnetic resonance data suggest that the SI behavior originates from several deep levels associated with intrinsic point defects. Micropipe densities in HPSI substrates have been demonstrated to be as low as 10 cm-2 in 2-in. substrates, and the room-temperature thermal conductivity of this material is near the theoretical maximum of 5 W/cm·K for 4H-SiC. Devices fabricated on these HPSI wafers do not exhibit any substrate related back-gating effects and have power densities as high as 5.2 W/mm with 63% power added efficiency.

  16. Defect studies of Vanadium doped 4H-SiC using optical admittance spectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, Wonwoo

    2005-03-01

    Semi-insulating SiC is an excellent candidate for a variety of applications, including microwave FET's and other devices for high power and high temperature applications. Vanadium acts as an amphoteric impurity in 4H-SiC with a V^3+/4+ acceptor level thought to be within 1 eV of the conduction band edge and a V^4+/5+ donor level known to be 1.6 eV below the conduction band edge. Vanadium is an efficient carrier trap and recombination center. We have studied vanadium doped 4H-SiC with the optical admittance spectroscopy (OAS) at room temperature. After taking into account phonon-assisted optical transitions, the estimated threshold energies can be compared with defect levels measured using thermal techniques. Compared with data reported in the literature, our results show that the defect level Ec -1.5 eV is close to the vanadium donor level and the other level Ec -0.67 eV is within the range of the value attributed to the vanadium acceptor level.

  17. Experimental characterization of a 4H SiC high voltage current limiting device

    NASA Astrophysics Data System (ADS)

    Nallet, F.; Planson, D.; Godignon, P.; Locatelli, M. L.; Lazar, M.; Chante, J. P.

    2001-12-01

    The aim of this paper is to show the first experimental results of a 600 V 4H-SiC current limiting device. This device limits the current which flows through it as the bias voltage between its two contacts increases. The static curves obtained from the first process run (T=300 K) show a current limitation capability with a saturation voltage ranging from 10 to 15 V. The device electrical characterization shows a R ON≈150 mΩ cm 2 and a current density of 150 A cm -2 under 50 V. The forward conduction is ensured by an N type implanted channel (doping species: nitrogen) on top of an P + implanted layer (doping species: aluminum). The post-implantation annealing of 1700 °C/30 min leads to a good electrical activation (80%) of the N channel/P + layer (analyzed by C(V) and SIMS methods) and a good channel mobility (100 cm 2 V -1 s -1 for a 2×10 17 cm-3 N compensated doping concentration). The prototypes of the second process run reach a saturation current density of 900 A cm -2 with a specific on-resistance of 13 mΩ cm 2. The 4H-SiC current limiting devices of the second run belong to the best set of Accu-MOSFETs devices reported in the literature.

  18. Water Status Related Root-to-Shoot Communication Regulates the Chilling Tolerance of Shoot in Cucumber (Cucumis sativus L.) Plants.

    PubMed

    Zhang, Zi-Shan; Liu, Mei-Jun; Gao, Hui-Yuan; Jin, Li-Qiao; Li, Yu-Ting; Li, Qing-Ming; Ai, Xi-Zhen

    2015-10-16

    Although root-to-shoot communication has been intensively investigated in plants under drought, few studies have examined root-to-shoot communication under chilling. Here we explored whether root-to-shoot communication contributes to the chilling-light tolerance of cucumber shoots and clarified the key signal involves in this communication. After leaf discs chilling-light treatment, the photoinhibitions of Photosystem I (PSI) and Photosystem II (PSII) were similar in leaf discs of two cucumber varieties (JY-3 and JC-4). When the whole plants, including roots, were chilled under light, the photosynthetic performances in JC-4 leaves decreased more seriously than that in JY-3 leaves. However, when the water status of leaves was maintained by warming roots or floating the attached leaves on water, the PSII activity and amount of PSI in the leaves of the two varieties were similar after chilling-light treatment. In addition, the differences of PSII activities and amount of PSI between the two varieties under whole plant chilling-light treatment were independent of ABA pretreatment. Above results indicate that (1) the better water status in leaves under chilling contributes to the higher chilling tolerance of JY-3; (2) the water status, rather than an ABA signal, dominates root-to-shoot communication under chilling and the chilling tolerance of cucumber shoot.

  19. Evidence of improved shooting precision in biathlon after 10 weeks of combined relaxation and specific shooting training.

    PubMed

    Laaksonen, Marko S; Ainegren, Mats; Lisspers, Jan

    2011-01-01

    The aim of this study was to test the hypothesis that a combined relaxation (applied tension release, ATR) and specific shooting training regimen may enhance shooting ability of biathlon athletes. Seven biathletes of high national level were randomized into an experimental group (age 20 ± 5 years; Vo2max 60 ± 8 mL kg(-1) min(-1)) and were asked to add this special training intervention to their regular training for 10 weeks, while five other biathletes served as controls (age 19 ± 2 years; Vo2max 57 ± 10 mL kg(-1) min(-1)). The shooting ability of the subjects was assessed before and after the intervention at rest and after roller skiing on a treadmill in a laboratory-based competition simulating assessment. After the intervention period, the experimental group demonstrated a significantly enhanced shooting performance compared to the control group. No changes in Vo2max or in heart rate and Vo2 responses were observed before and after the intervention in either group and there were no differences between the groups in these parameters. Thus, the preliminary conclusion is that a combination of ATR and specific shooting training seems to be instrumental in enhancing the shooting performance in biathlon.

  20. Field sports and conservation in the United Kingdom.

    PubMed

    Oldfield, T E E; Smith, R J; Harrop, S R; Leader-Williams, N

    2003-05-29

    Many natural habitats exist on privately owned land outside protected areas, but few governments can afford to enforce or subsidize conservation of this biodiversity. Even in some developed countries, conservation subsidy schemes have only achieved limited success. Fortunately, some landowners may be willing to accept management costs in return for other benefits, although this remains controversial when it involves the killing of charismatic species. For example, participants in British field sports, such as fox hunting and game-bird shooting, may voluntarily conserve important habitats that are required by quarry species. Here we report results from a multidisciplinary study that addressed this issue by focusing on three sites across central England. We found that landowners participating in field sports maintained the most established woodland and planted more new woodland and hedgerows than those who did not, despite the equal availability of subsidies. Therefore, voluntary habitat management appears to be important for biodiversity conservation in Britain. Current debates on the future of field sports in Britain, and similar activities globally, may benefit from considering their utility as incentives to conserve additional habitat on private land.

  1. Trust my face: cognitive factors of head fakes in sports.

    PubMed

    Kunde, Wilfried; Skirde, Stefanie; Weigelt, Matthias

    2011-06-01

    In many competitive sports, players try to deceive their opponents about their behavioral intentions by using specific body movements or postures called fakes. For example, fakes are performed in basketball when a player gazes in one direction but passes or shoots the ball in another direction to avert efficient defense actions. The present study aimed to identify the cognitive processes that underlie the effects of fakes. The paradigmatic situation studied was the head fake in basketball. Observers (basketball novices) had to decide as quickly as possible whether a basketball player would pass a ball to the left or to the right. The player's head and gaze were oriented in the direction of an intended pass or in the opposite direction (i.e., a head fake). Responding was delayed for incongruent compared to congruent directions of the player's gaze and the pass. This head fake effect was independent of response speed, the presence of a fake in the immediately preceding trial, and practice with the task. Five further experiments using additive-factors logic and locus-of-slack logic revealed a perceptual rather than motor-related origin of this effect: Turning the head in a direction opposite the pass direction appears to hamper the perceptual encoding of pass direction, although it does not induce a tendency to move in the direction of the head's orientation. The implications of these results for research on deception in sports and their relevance for sports practice are discussed.

  2. Understanding Life Skills Gained from and Reasons for Youth Participation in the Tennessee 4-H Sheep Skillathon

    ERIC Educational Resources Information Center

    Davis, Terra Kimes; Stripling, Christopher T.; Stephens, Carrie A.; Loveday, H. Dwight

    2016-01-01

    The high number of U.S. youth exhibiting at-risk behavior points to a lack of life skills development. We determined the effects of participating in one state's 4-H sheep skillathon on youths' life skills development and the youths' reasons for participating. The target population was 2014 Tennessee 4-H Sheep Skillathon participants (N = 153), and…

  3. Family Diversity in a Youth Organization: Involvement of Single-Parent Families and Stepfamilies in 4-H.

    ERIC Educational Resources Information Center

    Ganong, Lawrence H.

    1993-01-01

    Evaluated involvement of children from single-parent and stepparent households in 4-H clubs. Used case study approach, with data collected via written materials; interviews with 4-H staff; and mailed questionnaires from professional staff, paraprofessionals, and parents. Children from single-parent households were found to be underrepresented, as…

  4. Volunteer Educators' Influence on Youth Participation and Learning in 4-H STEM Learning by Design Programs

    NASA Astrophysics Data System (ADS)

    Worker, Steven Michael

    The purpose of this study was to describe the co-construction of three 4-H STEM (science, technology, engineering, and mathematics) learning by design programs by volunteer educators and youth participants in the 4-H Youth Development Program. The programs advanced STEM learning through design, a pedagogical approach to support youth in planning, designing, and making shareable artifacts. This pedagogical approach is a special case of project-based learning, related to the practices found in the science learning through design literature as well as the making and tinkering movements. Specifically, I explored adult volunteer educators' roles and pedagogical strategies implementing the 4-H Junk Drawer Robotics curriculum (Mahacek, Worker, and Mahacek, 2011) and how that, in turn, afforded and constrained opportunities for youth to display or report engagement in design practices; learning of STEM content; strengthening tool competencies; dispositions of resilience, reciprocity, and playfulness; and psychological ownership. The curriculum targeted middle school youth with a sequence of science inquiry activities and engineering design challenges. This study employed naturalist and multiple-case study methodology relying on participant observations and video, interviews with educators, and focus groups with youth within three 4-H educational robotics programs organized by adult 4-H volunteer educators. Data collection took place in 2014 and 2015 at Santa Clara with an educator and seven youth; Solano with three educators and eight youth; and Alameda with an educator and seven youth. Data analysis revealed six discrete categories of pedagogy and interactions that I labeled as participation structures that included lecture, demonstration, learning activity, group sharing, scripted build, and design & build. These participation structures were related to the observed pedagogical practices employed by the educators. There was evidence of youth engagement in design

  5. Somatic embryogenesis and organogenesis from cryopreserved shoot tips of Lilium Oriental hybrid ‘Siberia’

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Somatic embryogenesis and organogenesis were achieved from cryopreserved shoot tips of Lilium Oriental hybrid ‘Siberia’. Shoot tips (1.5-2 mm) were excised from adventitious shoots that were regenerated from basal leaf segments. Precultured shoot tips were then treated with MS containing 0.4 M sucro...

  6. Characterization of the Minimum Energy Paths for the Ring Closure Reactions of C4H3 with Acetylene

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1995-01-01

    The ring closure reaction of C4H3 with acetylene to give phenyl radical is one proposed mechanism for the formation of the first aromatic ring in hydrocarbon combustion. There are two low-lying isomers of C4H3; 1-dehydro-buta-l-ene-3-yne (n-C4H3) and 2-dehydro-buta-l-ene-3-yne (iso-C4H3). It has been proposed that only n-C4H3 reacts with acetylene to give phenyl radical, and since iso-C4H3 is more stable than n-C4H3, formation of phenyl radical by this mechanism is unlikely. We report restricted Hartree-Fock (RHF) plus singles and doubles configuration interaction calculations with a Davidson's correction (RHF+1+2+Q) using the Dunning correlation consistent polarized valence double zeta basis set (cc-pVDZ) for stationary point structures along the reaction pathway for the reactions of n-C4H3 and iso-C4H3 with acetylene. n-C4H3 plus acetylene (9.4) has a small entrance channel barrier (17.7) (all energetics in parentheses are in kcal/mol with respect to iso-C4H3 plus acetylene) and the subsequent closure steps leading to phenyl radical (-91.9) are downhill with respect to the entrance channel barrier. Iso-C4H3 Plus acetylene also has an entrance channel barrier (14.9) and there is a downhill pathway to 1-dehydro-fulvene (-55.0). 1-dehydro-fulvene can rearrange to 6-dehydro-fulvene (-60.3) by a 1,3-hydrogen shift over a barrier (4.0), which is still below the entrance channel barrier, from which rearrangement to phenyl radical can occur by a downhill pathway. Thus, both n-C4H3 and iso-C4H3 can react with acetylene to give phenyl radical with small barriers.

  7. Root-Shoot Signaling crosstalk involved in the shoot growth promoting action of rhizospheric humic acids

    PubMed Central

    Olaetxea, Maite; Mora, Verónica; García, Andrés Calderin; Santos, Leandro Azevedo; Baigorri, Roberto; Fuentes, Marta; Garnica, María; Berbara, Ricardo Luis Louro; Zamarreño, Angel Maria; Garcia-Mina, Jose M.

    2016-01-01

    ABSTRACT Numerous studies have shown the ability of humic substances to improve plant development. This action is normally reflected in an enhancement of crop yields and quality. However, the mechanisms responsible for this action of humic substances remain rather unknown. Our studies have shown that the shoot promoting action of sedimentary humic acids is dependent of its ability to increase root hydraulic conductivity through signaling pathways related to ABA, which in turn is affected in roots by humic acids in an IAA-NO dependent way. Furthermore, these studies also indicate that the primary action of humic acids in roots might also be physical, resulting from a transient mild stress caused by humic acids associated with a fouling-cleaning cycle of wall cell pores. Finally the role of alternative signal molecules, such as ROS, and corresponding signaling pathways are also discussed and modeled in the context of the above-mentioned framework. PMID:26966789

  8. Virtual(ly) Athletes: Where eSports Fit within the Definition of "Sport"

    ERIC Educational Resources Information Center

    Jenny, Seth E.; Manning, R. Douglas; Keiper, Margaret C.; Olrich, Tracy W.

    2017-01-01

    Electronic sports, cybersports, gaming, competitive computer gaming, and virtual sports are all synonyms for the term eSports. Regardless of the term used, eSports is now becoming more accepted as a "sport" and gamers are being identified as "athletes" within society today. eSports has even infiltrated higher education in the…

  9. Antidoping in paralympic sport.

    PubMed

    Van de Vliet, Peter

    2012-01-01

    This study reports in detail on the antidoping program of the Paralympic Movement to improve knowledge and optimize intervention programs, including educational and awareness initiatives. Data retrieved from annual statistics reports and historical records are complemented with personal observations. An overall incidence proportion of <1% of antidoping rule violations in the Paralympic Movement is reported, mainly resulting from urine testing during in-competition periods. This led to a total of 60 antidoping rule violations (of which 37 in the sport of International Paralympic Committee powerlifting) since 2000. A critical analysis of these data allows for an assessment of risk factors by sport. An efficient transfer of knowledge indicates the need to strengthen educational awareness, preferably imbedded in a multidisciplinary approach toward athletes' health. The particular case of autonomic dysreflexia is addressed as a separate theme.

  10. [Sports and osteoarthrosis].

    PubMed

    Schäfer, M; Dreinhöfer, K

    2009-12-01

    Many risk factors for developing osteoarthrosis exist. Osteoarthrosis is the most common cause of chronic disability in middle-aged and older people. On the one hand, physical exercise can lead to arthrosis; on the other hand, physical exercise is commonly used in preventing and treating it. Experimental and clinical studies have shown that increased high-impact running or competitive sports result in a higher risk for osteoarthrosis than moderate low-impact running. In particular, sudden-impact loading and twisting movements of the joints can result in premature osteoarthrosis. Also, sports with a high risk for injuries can lead to secondary osteoarthrosis. Preventive exercises to strengthen the skeletal muscles seem to have a pivotal role. There are different therapeutic approaches to osteoarthrosis, which will be more important in the future. Exercise should be a core treatment for people with osteoarthritis, irrespective of age, comorbidity, pain severity, or disability. Exercise should include local muscle strengthening and general aerobic fitness.

  11. Sports medicine and ethics.

    PubMed

    Testoni, Daniela; Hornik, Christoph P; Smith, P Brian; Benjamin, Daniel K; McKinney, Ross E

    2013-01-01

    Physicians working in the world of competitive sports face unique ethical challenges, many of which center around conflicts of interest. Team-employed physicians have obligations to act in the club's best interest while caring for the individual athlete. As such, they must balance issues like protecting versus sharing health information, as well as issues regarding autonomous informed consent versus paternalistic decision making in determining whether an athlete may compete safely. Moreover, the physician has to deal with an athlete's decisions about performance enhancement and return to play, pursuit of which may not be in the athlete's long-term best interests but may benefit the athlete and team in the short term. These difficult tasks are complicated by the lack of evidence-based standards in a field influenced by the lure of financial gains for multiple parties involved. In this article, we review ethical issues in sports medicine with specific attention paid to American professional football.

  12. Clustered data in sports research.

    PubMed

    Hayen, A

    2006-05-01

    Clustered, or dependent, data, arise commonly in sports medicine and sports science research, particularly in studies of sports injury and biomechanics, particularly in sports injury trials that are randomised at team or club level, in cross-sectional surveys in which groups of individuals are studied and in studies with repeated measures designs. Clustering, or positive correlation among responses, arises because responses and outcomes from the same cluster will usually be more similar than from different clusters. Study designs with clustering will usually required an increased sample size when compared to those without clustering. Ignoring clustering in statistical analyses can also lead to misleading conclusions, including incorrect confidence intervals and p-values. Appropriate statistical analyses for clustered data must be adopted. This paper gives some examples of clustered data and discusses the implications of clustering on the design and analysis of studies in sports medicine and sports science research.

  13. Sibling dynamics and sport expertise.

    PubMed

    Hopwood, M J; Farrow, D; MacMahon, C; Baker, J

    2015-10-01

    Family members are known to be highly influential in the development of sport expertise. To date, much of the research in this area has focused on parents, with less known about sibling influences on expertise. This investigation explored associations between sport expertise, sibling characteristics, and sibling participation in sport and physical activity. Athletes representing three skill levels provided details of sibling characteristics and participation in sport and physical activity via the Developmental History of Athletes Questionnaire. Elite athletes were more likely to be later-born children, while pre-elite and non-elite athletes were more likely to be first-born. Compared with siblings of non-elite athletes, siblings of elite athletes were more likely to have participated in regular physical activity and were more likely to have participated in sport at the pre-elite and elite levels. These results suggest siblings may play a key role in sport expertise development.

  14. Ugh! Sports physicals!

    PubMed

    McKeag, D B

    1996-08-01

    For the most part, physicians who take care of athletes tend to view the preparticipation physical exam (PPE) as a necessary but time-consuming and somewhat bothersome evil. It is not fun. It usually occurs at the hottest, most uncomfortable time of the year, and is often sandwiched between regular work responsibilities and family plans. ("I'd love to see you pitch tonight, Ian, but I've got to do sports physicals for 3 hours after work.").

  15. The neuropathology of sport

    PubMed Central

    Daneshvar, Daniel H.; Alvarez, Victor E.; Stein, Thor D.

    2014-01-01

    The benefits of regular exercise, physical fitness and sports participation on cardiovascular and brain health are undeniable. Physical activity reduces the risk for cardiovascular disease, type 2 diabetes, hypertension, obesity, and stroke, and produces beneficial effects on cholesterol levels, antioxidant systems, inflammation, and vascular function. Exercise also enhances psychological health, reduces age-related loss of brain volume, improves cognition, reduces the risk of developing dementia, and impedes neurodegeneration. Nonetheless, the play of sports is associated with risks, including a risk for mild TBI (mTBI) and, rarely, catastrophic traumatic injury and death. There is also growing awareness that repetitive mTBIs, such as concussion and subconcussion, can occasionally produce persistent cognitive, behavioral, and psychiatric problems as well as lead to the development of a neurodegeneration, chronic traumatic encephalopathy (CTE). In this review, we summarize the beneficial aspects of sports participation on psychological, emotional, physical and cognitive health, and specifically analyze some of the less common adverse neuropathological outcomes, including concussion, second-impact syndrome, juvenile head trauma syndrome, catastrophic sudden death, and CTE. CTE is a latent neurodegeneration clinically associated with behavioral changes, executive dysfunction and cognitive impairments, and pathologically characterized by frontal and temporal lobe atrophy, neuronal and axonal loss, and abnormal deposits of paired helical filament (PHF)-tau and 43 kDa TAR deoxyribonucleic acid (DNA)-binding protein (TDP-43). CTE often occurs as a sole diagnosis, but may be associated with other neurodegenerative disorders, including motor neuron disease (CTE-MND). Although the incidence and prevalence of CTE are not known, CTE has been reported most frequently in American football players and boxers. Other sports associated with CTE include ice hockey, professional

  16. The neuropathology of sport.

    PubMed

    McKee, Ann C; Daneshvar, Daniel H; Alvarez, Victor E; Stein, Thor D

    2014-01-01

    The benefits of regular exercise, physical fitness and sports participation on cardiovascular and brain health are undeniable. Physical activity reduces the risk for cardiovascular disease, type 2 diabetes, hypertension, obesity, and stroke, and produces beneficial effects on cholesterol levels, antioxidant systems, inflammation, and vascular function. Exercise also enhances psychological health, reduces age-related loss of brain volume, improves cognition, reduces the risk of developing dementia, and impedes neurodegeneration. Nonetheless, the play of sports is associated with risks, including a risk for mild TBI (mTBI) and, rarely, catastrophic traumatic injury and death. There is also growing awareness that repetitive mTBIs, such as concussion and subconcussion, can occasionally produce persistent cognitive, behavioral, and psychiatric problems as well as lead to the development of a neurodegeneration, chronic traumatic encephalopathy (CTE). In this review, we summarize the beneficial aspects of sports participation on psychological, emotional, physical and cognitive health, and specifically analyze some of the less common adverse neuropathological outcomes, including concussion, second-impact syndrome, juvenile head trauma syndrome, catastrophic sudden death, and CTE. CTE is a latent neurodegeneration clinically associated with behavioral changes, executive dysfunction and cognitive impairments, and pathologically characterized by frontal and temporal lobe atrophy, neuronal and axonal loss, and abnormal deposits of paired helical filament (PHF)-tau and 43 kDa TAR deoxyribonucleic acid (DNA)-binding protein (TDP-43). CTE often occurs as a sole diagnosis, but may be associated with other neurodegenerative disorders, including motor neuron disease (CTE-MND). Although the incidence and prevalence of CTE are not known, CTE has been reported most frequently in American football players and boxers. Other sports associated with CTE include ice hockey, professional

  17. Left preference for sport tasks does not necessarily indicate left-handedness: sport-specific lateral preferences, relationship with handedness and implications for laterality research in behavioural sciences.

    PubMed

    Loffing, Florian; Sölter, Florian; Hagemann, Norbert

    2014-01-01

    In the elite domain of interactive sports, athletes who demonstrate a left preference (e.g., holding a weapon with the left hand in fencing or boxing in a 'southpaw' stance) seem overrepresented. Such excess indicates a performance advantage and was also interpreted as evidence in favour of frequency-dependent selection mechanisms to explain the maintenance of left-handedness in humans. To test for an overrepresentation, the incidence of athletes' lateral preferences is typically compared with an expected ratio of left- to right-handedness in the normal population. However, the normal population reference values did not always relate to the sport-specific tasks of interest, which may limit the validity of reports of an excess of 'left-oriented' athletes. Here we sought to determine lateral preferences for various sport-specific tasks (e.g., baseball batting, boxing) in the normal population and to examine the relationship between these preferences and handedness. To this end, we asked 903 participants to indicate their lateral preferences for sport-specific and common tasks using a paper-based questionnaire. Lateral preferences varied considerably across the different sport tasks and we found high variation in the relationship between those preferences and handedness. In contrast to unimanual tasks (e.g., fencing or throwing), for bimanually controlled actions such as baseball batting, shooting in ice hockey or boxing the incidence of left preferences was considerably higher than expected from the proportion of left-handedness in the normal population and the relationship with handedness was relatively low. We conclude that (i) task-specific reference values are mandatory for reliably testing for an excess of athletes with a left preference, (ii) the term 'handedness' should be more cautiously used within the context of sport-related laterality research and (iii) observation of lateral preferences in sports may be of limited suitability for the verification of

  18. Left Preference for Sport Tasks Does Not Necessarily Indicate Left-Handedness: Sport-Specific Lateral Preferences, Relationship with Handedness and Implications for Laterality Research in Behavioural Sciences

    PubMed Central

    Loffing, Florian; Sölter, Florian; Hagemann, Norbert

    2014-01-01

    In the elite domain of interactive sports, athletes who demonstrate a left preference (e.g., holding a weapon with the left hand in fencing or boxing in a ‘southpaw’ stance) seem overrepresented. Such excess indicates a performance advantage and was also interpreted as evidence in favour of frequency-dependent selection mechanisms to explain the maintenance of left-handedness in humans. To test for an overrepresentation, the incidence of athletes' lateral preferences is typically compared with an expected ratio of left- to right-handedness in the normal population. However, the normal population reference values did not always relate to the sport-specific tasks of interest, which may limit the validity of reports of an excess of ‘left-oriented’ athletes. Here we sought to determine lateral preferences for various sport-specific tasks (e.g., baseball batting, boxing) in the normal population and to examine the relationship between these preferences and handedness. To this end, we asked 903 participants to indicate their lateral preferences for sport-specific and common tasks using a paper-based questionnaire. Lateral preferences varied considerably across the different sport tasks and we found high variation in the relationship between those preferences and handedness. In contrast to unimanual tasks (e.g., fencing or throwing), for bimanually controlled actions such as baseball batting, shooting in ice hockey or boxing the incidence of left preferences was considerably higher than expected from the proportion of left-handedness in the normal population and the relationship with handedness was relatively low. We conclude that (i) task-specific reference values are mandatory for reliably testing for an excess of athletes with a left preference, (ii) the term ‘handedness’ should be more cautiously used within the context of sport-related laterality research and (iii) observation of lateral preferences in sports may be of limited suitability for the

  19. Sports and disability.

    PubMed

    Wilson, Pamela E; Clayton, Gerald H

    2010-03-01

    Participation in recreational and competitive sports at an early age has long been touted as a positive influence on growth and development, and for fostering lifelong healthy lifestyles. The benefits of an active lifestyle include not only fitness, but the promotion of a sense of inclusion and improved self-esteem. These benefits are well documented in all populations, and their importance has been summarized in the recent Healthy People 2010 guidelines. The American Academy of Pediatrics has recently produced a summary statement on the benefits of activity for disabled children. They note that children with disabilities tend to have an overall lower level of fitness and an increased level of obesity. For this population, developing a lifelong desire to be active can be a simple means for limiting illness and much of the morbidity associated with sedentary lifestyles often associated with disability. For disabled youth, participation in disabled sports programs available nationally and internationally can be an effective means to promote such precepts. The goal of this focused review is to improve the learner's knowledge of the positive impact that active lifestyles can have on overall health in the disabled youth population and, as a result, modify their practice by incorporating recreational and competitive sport activities as part of improving overall patient care.

  20. Olympic sports and transsexuals.

    PubMed

    Gooren, Louis J

    2008-05-01

    Sex segregation in competitive sports is regarded as fair. Before puberty boys and girls do not differ in height, muscle and bone mass. Testosterone (T) exposure during puberty leads to an ultimate average greater height in men of 12-15 cm, longer and larger bones and muscle mass and strength and higher hemoglobin levels. Postpubertal androgen ablation reverses, at least in part, previous anabolic effects of T on muscle, bone mineral density and hemoglobin but the long bones remain longer and wider. T administration dose dependently increases muscle mass and maximal voluntary strength. Therefore, exogenous androgens, being performance enhancing drugs, are banned for all athletes. An issue is the participation in competitive sports of people with errors of sexual differentiation and particularly transsexuals who have been sex-reassigned. In view of the effects of T, a clear demarcation is whether sex reassignment has taken place before or after hormonal puberty. Pubertal effects of T are in part reversible but there is no reliable evidence as to its completeness. The International Olympic Committee (IOC) has taken an inevitably arbitrary decision with regard to participation of sex-reassigned transsexuals in elite sports: sex reassignment must have taken place at least two years earlier, hormone treatment must be appropriate for the reassigned sex and the reassigned sex must be legally recognized. The IOC policy is not binding for other organizations.

  1. Probe into the Elements of Leisure Sports Practice

    ERIC Educational Resources Information Center

    Li, Kaixian; Gao, Qun

    2008-01-01

    This paper probes into the basic elements of leisure sports practice by referencing literature materials and logic analyses. Studies show that leisure sports practice consists of six elements, including leisure sports ideas, leisure sports environment, leisure sports time, leisure sports activity, leisure sports skill, and leisure sports state.…

  2. Ontogeny of the Maize Shoot Apical Meristem[W][OA

    PubMed Central

    Takacs, Elizabeth M.; Li, Jie; Du, Chuanlong; Ponnala, Lalit; Janick-Buckner, Diane; Yu, Jianming; Muehlbauer, Gary J.; Schnable, Patrick S.; Timmermans, Marja C.P.; Sun, Qi; Nettleton, Dan; Scanlon, Michael J.

    2012-01-01

    The maize (Zea mays) shoot apical meristem (SAM) arises early in embryogenesis and functions during stem cell maintenance and organogenesis to generate all the aboveground organs of the plant. Despite its integral role in maize shoot development, little is known about the molecular mechanisms of SAM initiation. Laser microdissection of apical domains from developing maize embryos and seedlings was combined with RNA sequencing for transcriptomic analyses of SAM ontogeny. Molecular markers of key events during maize embryogenesis are described, and comprehensive transcriptional data from six stages in maize shoot development are generated. Transcriptomic profiling before and after SAM initiation indicates that organogenesis precedes stem cell maintenance in maize; analyses of the first three lateral organs elaborated from maize embryos provides insight into their homology and to the identity of the single maize cotyledon. Compared with the newly initiated SAM, the mature SAM is enriched for transcripts that function in transcriptional regulation, hormonal signaling, and transport. Comparisons of shoot meristems initiating juvenile leaves, adult leaves, and husk leaves illustrate differences in phase-specific (juvenile versus adult) and meristem-specific (SAM versus lateral meristem) transcript accumulation during maize shoot development. This study provides insight into the molecular genetics of SAM initiation and function in maize. PMID:22911570

  3. Sports drinks and dental erosion.

    PubMed

    Noble, Warden H; Donovan, Terence E; Geissberger, Marc

    2011-04-01

    Sports drinks were originally developed to improve hydration and performance in athletes taking part in intense or endurance sporting events. These drinks contain relatively high amounts of carbohydrates (sugars), salt, and citric acid. These ingredients create the potential for dental ramifications and overall public health consequences such as obesity and diabetes. High intake of sports drinks during exercise, coupled with xerostomia from dehydration, may lead to the possibility of erosive damage to teeth.

  4. Leptospirosis, Water Sports, and Chemoprophylaxis

    PubMed Central

    Haake, David A.; Dundoo, Manjula; Cader, Rumi; Kubak, Bernard M.; Hartskeerl, Rudy A.; Sejvar, James J.; Ashford, David A.

    2009-01-01

    Recreational activities, such as water sports and adventure travel, are emerging as an important risk factor for leptospirosis, a potentially fatal zoonosis. We report the clinical course of 2 patients who acquired leptospirosis through participation in water sports. Physicians caring for patients who participate in adventure travel involving water sports should be familiar with the risk factors for and diagnosis, prevention, and treatment of leptospirosis. PMID:11941571

  5. Characterization and Modeling of 4H-SiC Lateral MOSFETs for Integrated Circuit Design

    SciTech Connect

    Mudholkar, M; Mantooth, HA

    2013-06-01

    A new process in 4H-SiC is developed that features n-type buried and inversion channel lateral MOSFETs that are fabricated with several different channel lengths (2-8 mu m) and widths (8-32 mu m) and characterized over a wide temperature range (25 degrees C-225 degrees C). It is shown that the on-resistance of enhancement-mode SiC MOSFETs reduces with temperature despite a reduction in inversion mobility because of the interaction of interface states with temperature. To enable integrated circuit development using the developed MOSFETs, their electrical characteristics are modeled over geometry and temperature using the industry standard PSP MOSFET model. A new mathematical formulation to describe the presence of the interface states is also developed and implemented in the PSP model, and excellent agreement is shown between measurement and simulation using the modified PSP model.

  6. 2-Amino-4-(nitroalkyl)-4H-chromene-3-carbonitriles as New Cytotoxic Agents

    PubMed Central

    Zonouzi, Afsaneh; Mirzazadeh, Roghieh; Safavi, Maliheh; Kabudanian Ardestani, Sussan; Emami, Saeed; Foroumadi, Alireza

    2013-01-01

    A series of 2-amino-4-(nitroalkyl)-4H-chromene-3-carbonitriles were synthesized by an efficient multicomponent reaction in aqueous media using DBU as a catalyst at room temperature. Mild condition, environment friendly procedure and excellent yields are the main advantages of this procedure. The cytotoxic activity of target compounds were evaluated against three cancer cell lines MDA-MB-231, MCF-7 and T47D in comparison with etoposide as reference drug. Generally, all compounds showed good cell growth inhibitory activity with IC50 values less than 30 μg/mL. Their activities were comparable or more potent than standard drug etoposide. The 6-bromo- derivatives 7e and 7f showed promising cytotoxic activity with IC50 values in the range of 3.46–18.76 μg/mL, being more potent than etoposide against all tested cell lines. PMID:24523747

  7. Synthesis of a new class of pyrrolo[3,4-h]quinazolines with antimitotic activity.

    PubMed

    Spanò, Virginia; Montalbano, Alessandra; Carbone, Anna; Parrino, Barbara; Diana, Patrizia; Cirrincione, Girolamo; Castagliuolo, Ignazio; Brun, Paola; Issinger, Olaf-Georg; Tisi, Silvia; Primac, Irina; Vedaldi, Daniela; Salvador, Alessia; Barraja, Paola

    2014-03-03

    A new series of pyrrolo[3,4-h]quinazolines was conveniently prepared with a broad substitution pattern. A large number of derivatives was obtained and the cellular cytotoxicity was evaluated in vitro against 5 different human tumor cell lines with GI₅₀ values reaching the low micromolar level (1.3-19.8 μM). These compounds were able to induce cell death mainly by apoptosis through a mitochondrial dependent pathway. Selected compounds showed antimitotic activity and a reduction of tubulin polymerization in a concentration-dependent manner. Moreover, they showed anti-angiogenic properties since reduced in vitro endothelial cell migration and disrupted HUVEC capillary-like tube network in Matrigel.

  8. Pyrazolo[3,4-h]quinolines promising photosensitizing agents in the treatment of cancer.

    PubMed

    Spanò, Virginia; Parrino, Barbara; Carbone, Anna; Montalbano, Alessandra; Salvador, Alessia; Brun, Paola; Vedaldi, Daniela; Diana, Patrizia; Cirrincione, Girolamo; Barraja, Paola

    2015-09-18

    A new series of pyrazolo[3,4-h]quinolines, heteroanalogues of angelicin was conveniently prepared with a broad substitution pattern. A large number of derivatives was obtained and the cellular photocytotoxicity was evaluated in vitro against 5 different human tumor cell lines with GI50 values reaching the nanomolar level (14.52-0.04 μM). Selected compounds were able to photoinduce a massive cell death with the involvement of mitochondria. Their photodamage cellular targets were proteins and lipids and they did not cause any kind of DNA photodamage. This latter event is of considerable importance in the modulation of long term side effects, generally associated with the use of classical furocoumarins.

  9. 4H-SiC UV Photo Detector with Large Area and Very High Specific Detectivity

    NASA Technical Reports Server (NTRS)

    Yan, Feng; Shahid, Aslam; Franz, David; Xin, Xiaobin; Zhao, Jian H.; Zhao, Yuegang; Winer, Maurice

    2004-01-01

    Pt/4H-SiC Schottky photodiodes have been fabricated with the device areas up to 1 sq cm. The I-V characteristics and photo-response spectra have been measured and analyzed. For a 5 mm x 5 mm area device leakage current of 1 x 10(exp 15)A at zero bias and 1.2 x 10(exp 14)A at -IV have been established. The quantum efficiency is over 30% from 240nm to 320nm. The specific detectivity, D(sup *), has been calculated from the directly measured leakage current and quantum efficiency data and are shown to be higher than 10(exp 15) cmHz(sup 1/2)/W from 210nm to 350nm with a peak D(sup *) of 3.6 x 10(exp 15)cmH(sup 1/2)/W at 300nm.

  10. An Integrated Gate Driver in 4H-SiC for Power Converter Applications

    SciTech Connect

    Ericson, Milton Nance; Frank, Steven Shane; Britton, Charles; Janke, Devon D; Ezell, N Dianne Bull; Ryu, Sei_Hyung; Mantooth, Alan; Francis, Dr. Matt; Lanmichhane, Dr. Ranjan; Shepherd, Dr. Paul; Glover, Dr. Michael; Whitaker, Mr. Bret; Cole, Mr. Zach; Passmore, Mr. Brandon; Mcnutt, Tyler

    2014-01-01

    A gate driver fabricated in a 2-um 4H silicon carbide (SiC) process is presented. This process was optimized for vertical power MOSFET fabrication but accommodated integration of a few low-voltage device types including N-channel MOSFETs, resistors, and capacitors. The gate driver topology employed incorporates an input level translator, variable power connections, and separate power supply connectivity allowing selection of the output signal drive amplitude. The output stage utilizes a source follower pull-up device that is both overdriven and body source connected to improve rise time behavior. Full characterization of this design driving a SiC power MOSFET is presented including rise and fall times, propagation delays, and power consumption. All parameters were measured to elevated temperatures exceeding 300 C. Details of the custom test system hardware and software utilized for gate driver testing are also provided.

  11. 4H-SiC trench IGBT with lower on-state voltage drop

    NASA Astrophysics Data System (ADS)

    Liu, Yan-juan; Wang, Ying; Yu, Cheng-hao; Fei-Cao

    2017-03-01

    In this paper, a new 4H-SiC trench-gate IGBT structure incorporated a P+ shielding region in the emitter side is proposed in order to reduce the on-state voltage drop. Through the 2-D ATLAS simulation, the characteristics of the proposed structure are investigated and compared with the conventional structure. The simulation results indicate that the proposed structure exhibits an improvement in the following. Firstly, the on-state voltage drop is reduced by 32.75%. Secondly, the differential specific on-resistance is reduced by 42.33%. Finally, under the same on-state voltage drop, the turn-off energy is reduced more than 50.00%. At the end of the paper, it is explored that what effects the physical parameter of the P+ shielding region in the proposed structure have on the steady state performances.

  12. Low-energy electron scattering from C{sub 4}H{sub 9}OH isomers

    SciTech Connect

    Bettega, M. H. F.; Winstead, C.; McKoy, V.

    2010-12-15

    We present differential, integral, and momentum-transfer cross sections for elastic scattering of low-energy electrons by three butanol isomers, isobutanol, t-butanol, and 2-butanol. Our results were calculated with the Schwinger multichannel method in the static-exchange plus polarization approximation for collision energies from 1 to 50 eV. The present results are compared with previous calculations and measurements for the remaining C{sub 4}H{sub 9}OH isomer, n-butanol [Khakoo et al., Phys. Rev. A 78, 062714 (2008)]. Distinctive behavior is observed in the differential cross sections at collision energies between 5 and 10 eV. In particular, whereas n-butanol exhibits an f-wave scattering pattern, the other isomers exhibit d-wave behavior. A similar pattern is found in the related alkanes when comparing straight-chain versus branched isomers. We discuss the possible connection of this behavior to shape resonances that influence the scattering.

  13. 4H-SiC surface energy tuning by nitrogen up-take

    NASA Astrophysics Data System (ADS)

    Pitthan, E.; Amarasinghe, V. P.; Xu, C.; Gustafsson, T.; Stedile, F. C.; Feldman, L. C.

    2017-04-01

    Surface energy modification and surface wettability of 4H silicon carbide (0001) as a function of nitrogen adsorption is reported. The surface wettability is shown to go from primarily hydrophilic to hydrophobic and the surface energy was significantly reduced with increasing nitrogen incorporation. These changes are investigated by x-ray photoelectron spectroscopy and contact angle measurements. The surface energy was quantitatively determined by the Fowkes model and interpreted primarily in terms of the variation of the surface chemistry with nitrogen coverage. Variable control of SiC surface energies with a simple and controllable atomic additive such as nitrogen that is inert to etching, stable against time, and also effective in electrical passivation, can provide new opportunities for SiC biomedical applications, where surface wetting plays an important role in the interaction with the biological interfaces.

  14. High resolution alpha particle detectors based on 4H-SiC epitaxial layer

    NASA Astrophysics Data System (ADS)

    Zat'ko, B.; Dubecký, F.; Šagátová, A.; Sedlačová, K.; Ryć, L.

    2015-04-01

    We fabricated and characterized 4H-SiC Schottky diodes as a spectrometric detector of alpha particles. A thin blocking contact of Ni/Au (15 nm) was used to minimize the influence on alpha particles energy. Current-voltage characteristics of the detector were measured and a low current density below 0.3 nAcm-2 was observed at room temperature. 239Pu241Am244Cm was used as a source of alpha particles within the energy range between 5.1 MeV and 5.8 MeV for detector testing. The charge collection efficiency close to 100 % at reverse bias exceeding 50 V was determined. The best spectrometric performance shows a pulse height spectrum at a reverse bias of 200 V giving an energy resolution of 0.25 % in the full width and half maximum for 5.486 MeV of 241Am.

  15. Optical properties of mesoporous 4H-SiC prepared by anodic electrochemical etching

    NASA Astrophysics Data System (ADS)

    Rashid, Marzaini; Horrocks, B. R.; Healy, N.; Goss, J. P.; Horsfall, A. B.

    2016-11-01

    Porous silicon carbide was fabricated from n-type 4H-SiC substrates via anodic electrochemical etching in HF/ethanol solution and suspended in ethanol after ultrasonication. We observed three photoluminescence bands: two at wavelengths of 303 nm and 345 nm were above the bulk bandgap and one at 455 nm was below the bulk bandgap. These blue-shifted and red-shifted emission processes reveal the interplay between quantum confinement, surface states, and band edge related optical transitions. We propose a model to explain the frequently observed deviation from the quantum confinement in the photoluminesence trends for SiC-derived nanoparticles suspended in solvents. The quantum confined properties of the SiC structures provide a route for optical tunability in the UV-blue spectrum for use in novel photonic and biomedical applications.

  16. NaBH4/H2O2 Fuel Cells for Lunar and Mars Exploration

    NASA Astrophysics Data System (ADS)

    Luo, Nie; Miley, George H.; Mather, Joseph; Burton, Rodney; Hawkins, Glenn; Gimlin, Richard; Rusek, John; Valdez, Tom I.; Narayanan, Sekharipuram R.

    2006-01-01

    The properties of direct hydrogen peroxide (H2O2) fuel cells are studied in this research. Different catalysts and diffusion electrodes are tested to optimize the cell performance. Initial results indicate: 1) conversion efficiency over 60% at a practical current density of 250mA/cm2; 2) power density over 0.6 W/cm2, at room temperature and ambient pressure, better than that of any traditional fuel cell. Further, the unique combination of NaBH4 and H2O2, both of which are in an aqueous form, paves the way for a convenient unitized regeneration, which is inherently compact compared to other cells that use gas phase reactants, such as the conventional H2 and O2. These excellent properties make the NaBH4/H2O2 fuel cell a very promising candidate for future space power systems. A conceptual design to power Lunar and Mars missions is discussed.

  17. High current gain 4H-SiC bipolar junction transistor

    NASA Astrophysics Data System (ADS)

    Yourun, Zhang; Jinfei, Shi; Ying, Liu; Chengchun, Sun; Fei, Guo; Bo, Zhang

    2016-04-01

    A novel 4H-SiC BJT of high current gain with a suppressing surface traps effect has been proposed. It is effective to improve the current gain due to the lower electrons density in the surface region by extending the emitter metal to overlap the passivation layer on the extrinsic base surface. The electrons trapped in the extrinsic base surface induce the degeneration of SiC BJTs device performance. By modulating the electron recombination rate, the novel structure can increase the current gain to 63.2% compared with conventional ones with the compatible process technology. Optimized sizes are an overlapped metal length of 4 μm, as well as an oxide layer thickness of 50 nm. Project supported by the National Natural Science Foundation of China (Nos. 61306093, 61401075).

  18. Evidence for near-infrared photoluminescence of nitrogen vacancy centers in 4 H -SiC

    NASA Astrophysics Data System (ADS)

    Zargaleh, S. A.; Eble, B.; Hameau, S.; Cantin, J.-L.; Legrand, L.; Bernard, M.; Margaillan, F.; Lauret, J.-S.; Roch, J.-F.; von Bardeleben, H. J.; Rauls, E.; Gerstmann, U.; Treussart, F.

    2016-08-01

    We present evidence of near-infrared photoluminescence (PL) signature of nitrogen vacancy centers (NCVSi) - in silicon carbide (SiC). This center exhibits an S =1 ground state spin similar to the NV- center in diamond. We have performed photoluminescence excitation measurements at cryogenic temperature and demonstrated efficient photoexcitation of distinct photoluminescence from (NCVSi)- in 4 H -SiC. Furthermore, by correlating the energies of measured zero phonon lines (ZPLs) with theoretical values derived from hybrid density functional theory each of the ZPLs has been associated to the respective occupation of hexagonal (h ) and quasicubic (k ) lattice sites in close analogy to neutral divacancy centers (VCVSi) 0 in the same material. Finally, with the appropriate choice of excitation energy we demonstrated the selective excitation of (NCVSi) - PL with no contamination by (VCVSi) 0 PL, thereby opening the way towards the optical detection of (NCVSi) - electron spin resonance.

  19. Nitrogen-related point defect in 4H and 6H SiC

    NASA Astrophysics Data System (ADS)

    Zvanut, M. E.; van Tol, J.

    2007-12-01

    A nitrogen-related pair defect is studied as a function of doping density in 4H and 6H SiC. Electron paramagnetic resonance measurements verify that one nucleus in the pair is nitrogen, but the second part of the pair remains uncertain. The pair concentration varies monotonically with nitrogen concentration in samples with doping density 10 18-10 16 cm -3 and the boron concentration is an order of magnitude less than that of nitrogen. The pair center is not observed in the dark or under ultraviolet illumination when the nitrogen and boron concentrations are similar. We conclude that the pair is generated in all nitrogen-doped samples, but like the isolated nitrogen impurity, may be compensated by boron.

  20. Observations of deep levels in 4H-SiC using optoelectronic modulation spectroscopy

    NASA Astrophysics Data System (ADS)

    Chiu, Chi-Hsin; Parmiter, P. J. M.; Hilton, K.; Uren, M. J.; Swanson, J. G.

    2001-10-01

    Optoelectronic modulation spectroscopy (OEMS) has been used to reveal defect states in 4H-SiC. Pairs of magnitude and phase spectra have been used to infer whether they were electron or hole traps. Eleven discrete trap responses have been observed, eight were assigned as electron traps and three as hole traps. Five of these had been observed previously using optical admittance spectroscopy (OAS). An electron trap at 1.20 eV gave the most prominent response with a distinctive signature indicating that these traps were spatially delocalized with an extent of at least 1.35 nm, possibly associated with an extended defect structure. An unresolved continuum of be the superimposed response of an electron and hole trap at closely similar energies. Cosistency has been demonstrated with previous work using DLOS and OAS.

  1. Irradiation of 4H-SiC UV detectors with heavy ions

    SciTech Connect

    Kalinina, E. V. Lebedev, A. A.; Bogdanova, E.; Berenquier, B.; Ottaviani, L.; Violina, G. N.; Skuratov, V. A.

    2015-04-15

    Ultraviolet (UV) photodetectors based on Schottky barriers to 4H-SiC are formed on lightly doped n-type epitaxial layers grown by the chemical vapor deposition method on commercial substrates. The diode structures are irradiated at 25°C by 167-MeV Xe ions with a mass of 131 amu at a fluence of 6 × 10{sup 9} cm{sup −2}. Comparative studies of the optical and electrical properties of as-grown and irradiated structures with Schottky barriers are carried out in the temperature range 23–180°C. The specific features of changes in the photosensitivity and electrical characteristics of the detector structures are accounted for by the capture of photogenerated carriers into traps formed due to fluctuations of the conduction-band bottom and valence-band top, with subsequent thermal dissociation.

  2. What Is a Pediatric Sports Medicine Specialist?

    MedlinePlus

    ... Email Print Share What is a Pediatric Sports Medicine Specialist? Page Content Article Body If your child ... teens. What Kind of Training Do Pediatric Sports Medicine Specialists Have? Pediatric sports medicine specialists are medical ...

  3. American Orthopaedic Society for Sports Medicine

    MedlinePlus

    ... Upcoming Meetings Online Education Archived Meetings Faculty Resources Sports Medicine Fellowships Traveling Fellowship Submit an Abstract Submit ... Support AOSSM Research Publications Toggle American Journal of Sports Medicine Sports Health: A Multidisciplinary Approach Orthopaedic Journal ...

  4. Returning to sports after a back injury

    MedlinePlus

    ... medlineplus.gov/ency/patientinstructions/000518.htm Returning to sports after a back injury To use the sharing ... Back pain - returning to sports Which Type of Sport is Best? In deciding when and if to ...

  5. Mass spectrum of the butadiynyl radical (C4H; X2[summation operator]+)

    NASA Astrophysics Data System (ADS)

    Gu, Xibin; Guo, Ying; Kaiser, Ralf I.

    2005-11-01

    We utilized the crossed molecular beams method to synthesize the butadiynyl radical, C4H(X2[summation operator]+), via the reaction of dicarbon molecules with acetylene, under single collision conditions. Time-of-flight spectra of the radical were recorded at the center-of-mass angle (31°) of the parent ion (m/z = 49; C4H+) and of the fragments at m/z = 48 (C4+), m/z = 37 (C3H+), and m/z = 36 (C3+) This yields relative intensity ratios of I(m/z = 49):I(m/z = 48):I(m/z = 37):I(m/z = 36):I(m/z = 25):I(m/z = 24) = 1.0:0.67 +/- 0.07:0.47 +/- 0.06:0.2 +/- 0.02:0.08 +/- 0.02:0.04 +/- 0.02 at 70 eV electron impact energy. Signal at m/z = 13 (CH+) and 12 (C+) contribute less than 0.04 relative to the parent peak; the intensity of the 13C isotopic peak of the butadiynyl radical at m/z = 50 (13C12C3H+) depicts an intensity of 0.04 +/- 0.01 relative to m/z = 49. Employing linear scaling methods, the absolute ionization cross section of the butadiynyl radical was computed to be 8.8 +/- 1.8 × 10-16 cm2. These data can be employed in future space missions to detect the butadiynyl radical in oxygen-poor combustion flames and in the atmospheres of planets (Jupiter, Saturn, Uranus, Neptune and Pluto) and their moons (Titan, Triton and Oberon) in situ via matrix interval arithmetic assisted mass spectrometry.

  6. Picosecond pulsed laser ablation and micromachining of 4H-SiC wafers

    NASA Astrophysics Data System (ADS)

    Molian, Pal; Pecholt, Ben; Gupta, Saurabh

    2009-02-01

    Ultra-short pulsed laser ablation and micromachining of n-type, 4H-SiC wafer was performed using a 1552 nm wavelength, 2 ps pulse, 5 μJ pulse energy erbium-doped fiber laser with an objective of rapid etching of diaphragms for pressure sensors. Ablation rate, studied as a function of energy fluence, reached a maximum of 20 nm per pulse at 10 mJ/cm 2, which is much higher than that achievable by the femtosecond laser for the equivalent energy fluence. Ablation threshold was determined as 2 mJ/cm 2. Scanning electron microscope images supported the Coulomb explosion (CE) mechanism by revealing very fine particulates, smooth surfaces and absence of thermal effects including melt layer formation. It is hypothesized that defect-activated absorption and multiphoton absorption mechanisms gave rise to a charge density in the surface layers required for CE and enabled material expulsion in the form of nanoparticles. Trenches and holes micromachined by the picosecond laser exhibited clean and smooth edges and non-thermal ablation mode for pulse repetition rates less than 250 kHz. However carbonaceous material and recast layer were noted in the machined region when the pulse repetition rate was increased 500 kHz that could be attributed to the interaction between air plasma and micro/nanoparticles. A comparison with femtosecond pulsed lasers shows the promise that picosecond lasers are more efficient and cost effective tools for creating sensor diaphragms and via holes in 4H-SiC.

  7. Electrical and optical characterization of 4H-SiC diodes for particle detection

    NASA Astrophysics Data System (ADS)

    Schifano, Ramón; Vinattieri, Anna; Bruzzi, Mara; Miglio, Stefania; Lagomarsino, Stefano; Sciortino, Silvio; Nava, Filippo

    2005-05-01

    The electronic and optical properties of several (medium to high quality) 4H-SiC epitaxial sensors for particle detection have been studied. The samples are n-doped Schottky diodes with different nitrogen concentrations (6×1013cm-3-5×1015cm-3) and thicknesses (20-40μm). A full electrical and optical characterization has been performed by capacitance versus voltage measurements and near-band-edge low-temperature photoluminescence. The effective doping along the epilayer and the depletion width have been determined and data are consistent with the charge collection efficiency characterization performed with a minimum ionizing β-source. All the investigated samples exhibit a 100% collection efficiency. In particular, the best samples yield a highly reproducible signal, well separated from the pedestal. Photoluminescence results show a linear relationship between the effective doping and the ratio of nitrogen-bound excitonic emission (Q0) and free excitonic line (I76), in agreement with a previous work on 4H-SiC with a higher doping concentration [I. G. Ivanov, C. Hallin, A. Henry, O. Kordina, and E. Janzén, J. Appl. Phys. 80, 3504 (1996)]. Moreover we show that the dependence of the major spectral features as a function of the penetration depth of the exciting laser beam can quantitatively provide information on substrate contribution to the photoluminescence. In conclusion, we bring evidence that a detailed characterization of SiC-based detectors, by all optical techniques, yields an accurate value for the net doping and gives a qualitative information on the epilayer thickness prior to any electrical wafer tests.

  8. Electrical and optical characterization of 4H-SiC diodes for particle detection

    SciTech Connect

    Schifano, Ramon; Vinattieri, Anna; Bruzzi, Mara; Miglio, Stefania; Lagomarsino, Stefano; Sciortino, Silvio; Nava, Filippo

    2005-05-15

    The electronic and optical properties of several (medium to high quality) 4H-SiC epitaxial sensors for particle detection have been studied. The samples are n-doped Schottky diodes with different nitrogen concentrations (6x10{sup 13} cm{sup -3}-5x10{sup 15} cm{sup -3}) and thicknesses (20-40 {mu}m). A full electrical and optical characterization has been performed by capacitance versus voltage measurements and near-band-edge low-temperature photoluminescence. The effective doping along the epilayer and the depletion width have been determined and data are consistent with the charge collection efficiency characterization performed with a minimum ionizing {beta}-source. All the investigated samples exhibit a 100% collection efficiency. In particular, the best samples yield a highly reproducible signal, well separated from the pedestal. Photoluminescence results show a linear relationship between the effective doping and the ratio of nitrogen-bound excitonic emission (Q{sub 0}) and free excitonic line (I{sub 76}), in agreement with a previous work on 4H-SiC with a higher doping concentration [I. G. Ivanov, C. Hallin, A. Henry, O. Kordina, and E. Janzen, J. Appl. Phys. 80, 3504 (1996)]. Moreover we show that the dependence of the major spectral features as a function of the penetration depth of the exciting laser beam can quantitatively provide information on substrate contribution to the photoluminescence. In conclusion, we bring evidence that a detailed characterization of SiC-based detectors, by all optical techniques, yields an accurate value for the net doping and gives a qualitative information on the epilayer thickness prior to any electrical wafer tests.

  9. Hydride CVD Hetero-epitaxy of B12P2 on 4H-SiC

    NASA Astrophysics Data System (ADS)

    Frye, C. D.; Saw, C. K.; Padavala, Balabalaji; Nikolić, R. J.; Edgar, J. H.

    2017-02-01

    Icosahedral boron phosphide (B12P2) is a wide bandgap semiconductor (3.35 eV) that has been reported to "self-heal" from high-energy electron bombardment, making it attractive for potential use in radioisotope batteries, radiation detection, or in electronics in high radiation environments. This study focused on improving B12P2 hetero-epitaxial films by growing on 4H-SiC substrates over the temperature range of 1250-1450 °C using B2H6 and PH3 precursors in a H2 carrier gas. XRD scans and Laue transmission photographs revealed that the epitaxial relationship was (0001)< 11 2 bar 0 > B12P2 ∥ (0001)< 11 2 bar 0 > 4 H - SiC . The film morphology and crystallinity were investigated as a function of growth temperature and growth time. At 1250 °C, films tended to form rough, polycrystalline layers, but at 1300 and 1350 °C, films were continuous and comparatively smooth (RRMS ≤ 7 nm). At 1400 or 1450 °C, the films grew in islands that coalesced as the films became thicker. Using XRD rocking curves to evaluate the crystal quality, 1300 °C was the optimum growth temperature tested. At 1300 °C, the rocking curve FWHM decreased with increasing film thickness from 1494 arcsec for a 1.1 μm thick film to 954 arcsec for a 2.7 μm thick film, suggesting a reduction in defects with thickness.

  10. Device design assessment of 4H-SiC n-IGBT - A simulation study

    NASA Astrophysics Data System (ADS)

    Usman, Muhammad; Nawaz, Muhammad

    2014-02-01

    A theoretical design assessment is presented using two dimensional numerical computer aided design (TCAD) tool for 15-20 kV 4H-SiC IGBTs. Physical parameters of the layer structures such as drift layer thickness, doping in the drift layer, JFET region width and interface charges underneath the gate region are varied to predict the device performance. Performance is further assessed at different temperatures and with different carrier lifetime in the drift layer. Using identical set of physical device parameters (doping, thicknesses), simulated structure was first calibrated with the experimental data. Simulations show that a minority carrier lifetime in the drift layer of 1.0-1.6 μs produces a close match with the experimental device. An on-resistance first decays with temperature (i.e., increased in ionization level, and increase in minority carrier lifetime), stays nearly constant with further increase in the temperature (may be all carriers are now fully ionized and increase in carrier lifetime is compensated with decrease in the carrier mobility) and finally increases linearly with temperature (>450 K) due to decrease in the carrier mobility. A significant increase in the forward voltage drop is observed with the presence of interface trap charges. Increasing JFET region width slightly decreases the forward on-state voltage. A drift layer of at least 175 μm thick with a doping concentration of < 2.0 × 1014 cm-3 is required to get a blocking voltage of 20 kV for 4H-SiC IGBTs assuming a minority carrier lifetime of 1 μs in the drift layer.

  11. Male genital trauma in sports.

    PubMed

    Hunter, Stanley R; Lishnak, Timothy S; Powers, Andria M; Lisle, David K

    2013-04-01

    Male genital trauma is a rare but potentially serious sports injury. Although such an injury can occur by many different mechanisms, including falls, collisions, straddle injuries, kicks, and equipment malfunction, the clinical presentation is typically homogeneous, characterized by pain and swelling. Almost all sports-related male genital injury comes from blunt force trauma, with involvement of scrotal structures far more common than penile structures. Most injuries can be treated conservatively, but catastrophic testicular injury must first be ruled out. Despite being relatively uncommon compared with other sports injuries, more than half of all testicular injuries are sustained during sports.

  12. Musculoskeletal ultrasound for sports injuries.

    PubMed

    Tok, F; Özçakar, L; De Muynck, M; Kara, M; Vanderstraeten, G

    2012-12-01

    Each day, the role of musculoskeletal ultrasound (US) in the management of sports injuries is being consolidated. Yet, there is no doubt that the probe of US is (should be) the stethoscope of musculoskeletal physicians dealing with sports medicine. Not only for the diagnosis, but also for the close follow-up of the athletes and during likely onward interventions for their treatment, would US be of paramount importance. Accordingly, in this review paper on common sports injuries, we tried to shed light into the actual role of US in the clinical practice of sports medicine.

  13. Return to sport following amputation.

    PubMed

    Matthews, D; Sukeik, M; Haddad, F

    2014-08-01

    Amputation in athletes has a substantial impact on lifestyle and sporting activity, as well as self-perception and quality of life. The impact of limb loss on athletic ability will vary depending on the cause of amputation and the anatomical location of the amputation. The use of sporting activity for rehabilitation of amputees was first introduced in 1944 at Stoke Mandeville Hospital. The first international paralympic games were founded in 1960. Following these events the opportunity to participate in sport following limb loss has increased significantly. Sport participation has been aided by the development of sporting prostheses, however multiple factors will determine the exact prosthesis used. These include the nature of the sporting activity as well as the level of the amputation. The biomechanics involved in walking and running are altered following the loss of a limb or part thereof. This can cause subsequent degenerative changes within the remaining joints on the amputated limb as well as the contralateral limb. Factors affecting return to sporting activity are multivariate and inter-related, including patient factors, surgical factors, nature and level of the sporting activity and prosthetic factors. The authors review current literature, detail predictive factors of return to sport and the physical and psychosocial impact on patients following limb amputation.

  14. Charcot-Marie-Tooth Disease Type 4H Resulting from Compound Heterozygous Mutations in FGD4 from Nonconsanguineous Korean Families.

    PubMed

    Hyun, Young Se; Lee, Jinho; Kim, Hye Jin; Hong, Young Bin; Koo, Heasoo; Smith, Alec S T; Kim, Deok-Ho; Choi, Byung-Ok; Chung, Ki Wha

    2015-11-01

    Charcot-Marie-Tooth disease type 4H (CMT4H) is an autosomal recessive demyelinating subtype of peripheral enuropathies caused by mutations in the FGD4 gene. Most CMT4H patients are in consanguineous Mediterranean families characterized by early onset and slow progression. We identified two CMT4H patients from a Korean CMT cohort, and performed a detailed genetic and clinical analysis in both cases. Both patients from nonconsanguineous families showed characteristic clinical manifestations of CMT4H including early onset, scoliosis, areflexia, and slow disease progression. Exome sequencing revealed novel compound heterozygous mutations in FGD4 as the underlying cause in both families (p.Arg468Gln and c.1512-2A>C in FC73, p.Met345Thr and c.2043+1G>A (p.Trp663Trpfs*30) in FC646). The missense mutations were located in highly conserved RhoGEF and PH domains which were predicted to be pathogenic in nature by in silico modeling. The CMT4H occurrence frequency was calculated to 0.7% in the Korean demyelinating CMT patients. This study is the first report of CMT4H in Korea. FGD4 assay could be considered as a means of molecular diagnosis for sporadic cases of demyelinating CMT with slow progression.

  15. Measurement of Optical, Mechanical and Transport properties of the hexagonal closed packed 4H polytype of metallic silver

    NASA Astrophysics Data System (ADS)

    Chakraborty, Indrani; Shirodkar, Sharmila N.; Gohil, Smita; Waghmare, Umesh; Ayyub, Pushan

    2013-03-01

    Optical, mechanical and transport property measurements were done on the hexagonal closed packed (hcp) 4H polytype of Ag with stacking sequence ABCBABCB.. grown as bulk films on Al2O3 substrates. Diffused reflectance measurements done on the 4H films showed a general loss of reflectivity amounting to a decrease of 35% as compared to normal fcc (3C) Ag near 500 nm with a blueshift of 5nm in the bulk plasmon frequency, possibly due to the modified electronic structure of the hcp form. Raman spectroscopic measurements showed the appearance of a peak at 64.3 cm-1 at 4K which underwent ``Mode softening,'' that is shifted to lower wave numbers with increase of temperature and disappeared above 350K. Low temperature transport measurements done on 4H films gave the in-plane resistivity value to be 39 times higher than that of a similarly synthesized fcc Ag film at 295 K. Vicker's microhardness measurements done on the 4H films showed that the 4H samples to be almost 5 times harder than the 3C Ag. Density functional theory simulations were done to obtain the phonon dispersion, band structure and nature of Fermi surface for the 4H Ag which corroborated with the experimental observations. The 4H form appears to be a much less metallic, darker and harder form of Ag.

  16. Electronic spectrum and photodissociation chemistry of the linear methyl propargyl cation H2C4H3+

    NASA Astrophysics Data System (ADS)

    Catani, Katherine J.; Muller, Giel; da Silva, Gabriel; Bieske, Evan J.

    2017-01-01

    The electronic spectrum of the methyl propargyl cation (2-butyn-1-yl cation, H2C4H3+) is measured over the 230-270 nm range by photodissociating the bare cation and its Ar and N2 tagged complexes in a tandem mass spectrometer. The observed '1A←'1A band system has an origin at 37 753 cm-1 for H2C4H3+ , 37738 cm-1 for H2C4H3+ - Ar, and 37 658 cm-1 for H2C4H3+ - N2. The methyl propargyl cation photodissociates to produce either C2H3++C2H2 (protonated acetylene + acetylene) or H2C4H+ +H2 (protonated diacetylene + dihydrogen). Photodissociation spectra of H2C4H3+ , H2C4H3+ - Ar, and H2C4H3+ - N2 exhibit similar vibronic structure, with a strong progression of spacing 630 cm-1 corresponding to excitation of the C—C stretch mode. Interpretation of the spectra is aided by ground and excited state calculations using time dependent density functional theory at the ωB97X-D/aug-cc-pVDZ level of theory. Ab initio calculations and master equation simulations were used to interpret the dissociation of H2C4H3+ on the ground state manifold. These calculations support the experimentally observed product branching ratios in which acetylene elimination dominates and also suggests that channel switching occurs at higher energies to favor H2 elimination.

  17. Connecting Kids To The Universe: Partnering With 4-H Youth Development To Pilot 'Afterschool Universe' In New York

    NASA Astrophysics Data System (ADS)

    Schaff, Nancy

    2008-05-01

    4-H Youth Development - as the youth program of the Cooperative Extension system associated with the land grant university in every state - is an ideal partner for statewide dissemination of EPO programs. With funding from a Chandra Cycle 9 EPO grant we are piloting `Afterschool Universe’ in five urban locations in New York State. `Afterschool Universe’ is an education/outreach effort sponsored by NASA's Beyond Einstein program and was developed in partnership with the Imagine the Universe EPO program. The program is targeted at middle school students in out-of-school-time settings and explores basic astronomy concepts focused on the Universe beyond the solar system. Consisting of 12 sessions of engaging hands-on activities, the flexibly structured program can be used in a variety of settings, including astronomy days, youth groups, summer camps, and afterschool programs. Partnering with 4-H Youth Development helps us reach large numbers of underserved and underrepresented minority youth and girls in widely dispersed areas of New York and fits ideally with the current national 4-H SET (science, engineering, and technology) initiative and emphasis on 4-H afterschool programming. The pilot program provides teaching kits and workshops for program leaders. Our 4-H county partners recruit afterschool program staff, science center staff, 4-H volunteers, 4-H teens, and other youth group leaders as workshop participants. The 4-H program will house and loan the kit to trained leaders. By providing kits and training in 2008, we are gearing up for International Year of Astronomy programs in 2009 in out-of-school settings. Based on pilot results, we will seek additional funding to expand the program. The poster will discuss kit development, 4-H partnership, workshops, participating organizations, target audiences, successes, and challenges.

  18. Implantation-Free 4H-SiC Bipolar Junction Transistors with Double Base Epi-layers

    DTIC Science & Technology

    2007-05-14

    gain 4H-SiC NPN power bipolar junction transistor ,” IEEE Electron Device Letters, vol. 24, pp. 327-329, May 2003. [3] C.-F. Huang and J. A. Cooper...Jr., “High current gain 4H-SiC NPN Bipolar Junction Transistors ,” IEEE Electron Device Letters, vol. 24, pp. 396-398, Jun. 2003. [4] Sumi...Implantation-Free 4H-SiC Bipolar Junction Transistors with Double Base Epi-layers Jianhui Zhang, member, IEEE, Xueqing, Li, Petre Alexandrov

  19. Micropropagation of Vaccinium sp. by in vitro axillary shoot proliferation.

    PubMed

    Litwińczuk, Wojciech

    2013-01-01

    The Vaccinium genus contains several valuable fruit and ornamental species, among others: highbush blueberry (Vaccinium × corymbosum L.), cranberry (Vaccinium macrocarpon Ait.), and lingonberry (Vaccinium vitis-idaea L.). In some most popular and valuable cultivars, the conventional propagation methods, exploiting hard or soft wood cuttings, are inefficient. The demand for nursery plants could be fulfilled only by micropropagation. In principle cultivars are propagated in vitro through similar three-stage method, based on subculture of shoot explants on different culture media supplemented with IAA (0-4 mg/L) and 2iP (5-10 mg/L), and rooting shoots in vivo. The obtained plantlets are transferred to peat substrate and grown in the glasshouse until the end of growing period. The development of adventitious shoots should be monitored and controlled during in vitro stages. Many clones have specific requirements for growing conditions and/or are recalcitrant.

  20. WIND1 Promotes Shoot Regeneration through Transcriptional Activation of ENHANCER OF SHOOT REGENERATION1 in Arabidopsis[OPEN

    PubMed Central

    Ohnuma, Mariko; Kurata, Tetsuya; Nakata, Masaru; Ohme-Takagi, Masaru

    2017-01-01

    Many plant species display remarkable developmental plasticity and regenerate new organs after injury. Local signals produced by wounding are thought to trigger organ regeneration but molecular mechanisms underlying this control remain largely unknown. We previously identified an AP2/ERF transcription factor WOUND INDUCED DEDIFFERENTIATION1 (WIND1) as a central regulator of wound-induced cellular reprogramming in plants. In this study, we demonstrate that WIND1 promotes callus formation and shoot regeneration by upregulating the expression of the ENHANCER OF SHOOT REGENERATION1 (ESR1) gene, which encodes another AP2/ERF transcription factor in Arabidopsis thaliana. The esr1 mutants are defective in callus formation and shoot regeneration; conversely, its overexpression promotes both of these processes, indicating that ESR1 functions as a critical driver of cellular reprogramming. Our data show that WIND1 directly binds the vascular system-specific and wound-responsive cis-element-like motifs within the ESR1 promoter and activates its expression. The expression of ESR1 is strongly reduced in WIND1-SRDX dominant repressors, and ectopic overexpression of ESR1 bypasses defects in callus formation and shoot regeneration in WIND1-SRDX plants, supporting the notion that ESR1 acts downstream of WIND1. Together, our findings uncover a key molecular pathway that links wound signaling to shoot regeneration in plants. PMID:28011694