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…

  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. 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…

  4. [Polymeric hearing protectors in sport shooting].

    PubMed

    Lwow, Felicja; Szmigiero, Leszek

    2007-01-01

    Using hearing protectors during exposition to noise is fundamental to hearing loss prevention. The optimal choice of hearing protectors should take into consideration not only the physical characteristics of the acoustic environment which imply the traumatic action of noise, but also some individual preferences of the user. All contemporary produced hearing protectors both earmuffs as well as earplugs are made of synthetic polymers e.g. ABS, polyvinylchloride, polyethylene, polyurethathane, silicone rubbers. The type of the material used determines hardness, incompressibility and plasticity of the hear protector and may cause some discomfort. A special group of individuals exposed to noise are sport shooters in which (whose) case the exposition to impact noise is several times higher above standards. The aim of this work was an appraisal of the individual preferences in the choice of hearing protectors. The properties of polymers used for the production of hearing protectors were also taken into consideration. 104 females and 93 males representing master class were interviewed in this study. The analysis of the answers indicated that abandoning of hearing protectors by some shooters is due to the frequent skin irritations, overheating in the ear canal and allergy. Shooters linked these problems with the materials used for the production of hearing protectors. Earplugs were preferred by females, whereas males indicated earmuffs as their preferred choice. Females preferred earplugs made of soft materials which can be easily fitted to ear canal. Those males who used earplugs preferred protectors made of hard plastics as they thought this make better insulation. It can be concluded that the choice of the hearing protectors should not be done on the basis acoustic signal characteristics only, but also should reduce some discomforts resulting from properties of the materials used for their production. PMID:18251202

  5. A Guide to Instruction in the Shooting Sports-Rifles; Air Rifles; Shotguns; Pistols; Hunter Safety.

    ERIC Educational Resources Information Center

    Niemeyer, Roy K.; And Others

    Prepared for instruction in the use of rifles, air guns, shotguns, pistols, and hunter safety, this guide supplements other materials which are available from the National Rifle Association of America, the National Shooting Sports Foundation, the American Association for Health, Physical Education, and Recreation, industry, and other sources. The…

  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 Iowa teacher and…

  8. Managing 4-H Volunteer Staff: A 4-H Intern Report.

    ERIC Educational Resources Information Center

    Martin, Hope M.

    The 4-H intern report organizes concepts and materials to aid the extension worker in his role as coordinator and trainer of 4-H volunteer staff. A 10-item task analysis of the extension worker--4-H and youth--as volunteer leader coordinator is presented. The importance of managing a volunteer staff is touched upon, and models for job descriptions…

  9. Keeping 4-H Volunteer Leaders.

    ERIC Educational Resources Information Center

    Smith, Keith L.; Bigler, Nancy M.

    1985-01-01

    This study showed that continuing and discontinuing volunteer 4-H Club leaders are significantly different in their geographical location, number of children in family, and number of children in family who have participated in 4-H. These variables may affect the volunteer's decision to continue serving as a 4-H Club leader. (Author/CT)

  10. Shoot branching.

    PubMed

    Ward, Sally P; Leyser, Ottoline

    2004-02-01

    The mature form of a plant shoot system is an expression of several genetically controlled traits, many of which are also environmentally regulated. A major component of this architectural variation is the degree of shoot branching. Recent results indicate conserved mechanisms for shoot branch development across the monocots and eudicots. The existence of a novel long-range branch-inhibiting signal has been inferred from studies of branching mutants in pea and Arabidopsis. PMID:14732444

  11. 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…

  12. 4-H in the 70's.

    ERIC Educational Resources Information Center

    Extension Service (USDA), Washington, DC.

    Developed under the leadership of the 1970 and 1971 Extension Committee on Organization and Policy 4-H Youth Subcommittees, the brochure offers a statement of potential and new directions for Extension 4-H youth programs. Opening sections deal with the functions of 4-H and balanced 4-H program expansion to serve seven million youth. Succeeding…

  13. 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,…

  14. 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…

  15. 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…

  16. 4-H Clover Awareness Teaching Guide.

    ERIC Educational Resources Information Center

    Rutherford, Barbara; Leach, Jennifer

    The purpose of this teaching guide is to introduce children in grades 1-4 and their parents to the 4-H program without the long-term commitment of the traditional 4-H club. The 4-H Clover Awareness Program was designed as an after-school program; however, it could be used in other settings such as a day camp. In addition to introducing children to…

  17. The Toddler: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    Part of a series for 4-H members between 9 and 19 years of age, this age-graded guide is designed to help children and adolescents: (1) understand the toddler's physical, mental, social, and emotional growth; (2) learn to care for a toddler; and (3) choose types of play that toddlers enjoy. Contents include suggestions on projects that 4-H members…

  18. 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:…

  19. 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,…

  20. 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)

  1. 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…

  2. Middle Childhood: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    Part of a series for 4-H members between 9 and 19 years of age, this age-graded guide to the development of 6-, 7-, and 8-year-olds aims to help 4-H members who are children and adolescents themselves: (1) understand the physical, mental, social, and emotional development of children in middle childhood; (2) learn to care for a child in middle…

  3. 4-H Textile Science Beginner Projects.

    ERIC Educational Resources Information Center

    Scholl, Jan

    This packet contains three 4-H projects for students beginning the sewing sequence of the textile sciences area. The projects cover basics of sewing using sewing machines, more difficult sewing machine techniques, and hand sewing. Each project provides an overview of what the student will learn, what materials are needed, and suggested projects…

  4. Multi-state 4-H energy program

    SciTech Connect

    Bakker, U.B.; Garthe, J.W.

    1983-06-01

    Through Agricultural Engineering 4-H Energy Programs, youth can be educated to gain knowledge, increase hands on skills, and incorporate energy-saving techniques into their lifestyle. In a pilot multi-state energy program tested by 13 states, youth increased their energy awareness.

  5. 4-H for Central City Minorities

    ERIC Educational Resources Information Center

    Paige, Joseph C.

    1970-01-01

    Joseph C. Paige is the Dean of Community Education and Director of Cooperative Extension Service of the only urban Land-Grant College, Federal City College, in Washington, D.C. Here he is interviewed about 4-H with children of poor ethnic groups in the District of Columbia. (NL)

  6. The Preschooler: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    Intended for 4-H participants who plan and implement activities in the area of child development, this booklet provides a study guide to help young learners: (1) gain understanding of a preschool child's physical, mental, social, and emotional growth; (2) learn to care for a preschooler and promote preschoolers' feelings of security and safety;…

  7. The Infant: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    This booklet for 4-H members who elect to undertake projects in child caregiving provides guidelines and information that help children and adolescents between 9 and 19 years of age: (1) understand infants' physical, mental, social, and emotional growth; (2) learn to care for a baby and promote feelings of security and safety; and (3) choose types…

  8. 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,…

  9. 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…

  10. 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'…

  11. 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…

  12. Shoot dieback in pecan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two shoot dieback maladies (SDM) of pecan [Carya illinoinensis (Wangenh.) C. Koch] are of unknown cause and can adversely affect canopy health. They occur during either early spring (SpSDM) or early summer (SuSDM). Field evaluation found that both maladies predominately occur on shoots retaining p...

  13. 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.

  14. 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…

  15. Thermochemistry of disputed soot formation intermediates C4H3 and C4H5.

    PubMed

    Wheeler, Steven E; Allen, Wesley D; Schaefer, Henry F

    2004-11-01

    Accurate isomeric energy differences and standard enthalpies of formation for disputed intermediates in soot formation, C(4)H(3) and C(4)H(5), have been determined through systematic extrapolations of ab initio energies. Electron correlation has been included through second-order Z-averaged perturbation theory (ZAPT2), and spin-restricted, open-shell coupled-cluster methods through triple excitations [ROCCSD, ROCCSD(T), and ROCCSDT] utilizing the correlation-consistent hierarchy of basis sets, cc-pVXZ (X = D, T, Q, 5, and 6), followed by extrapolations to the complete basis set limit via the focal point method of Allen and co-workers. Reference geometries were fully optimized at the ROCCSD(T) level with a TZ(2d1f,2p1d) basis set. Our analysis finds that the resonance-stabilized i-C(4)H(3) and i-C(4)H(5) isomers lie 11.8 and 10.7 kcal mol(-1) below E-n-C(4)H(3) and E-n-C(4)H(5), respectively, several kcal mol(-1) (more, less) than reported in recent (diffusion Monte Carlo, B3LYP density-functional) studies. Moreover, in these systems Gaussian-3 (G3) theory suffers from large spin contamination in electronic wave functions, poor reference geometries, and anomalous vibrational frequencies, but fortuitous cancellation of these sizable errors leads to isomerization energies apparently accurate to 1 kcal mol(-1). Using focal-point extrapolations for isodesmic reactions, we determine the enthalpies of formation (delta(f)H(0) (composite function)) for i-C(4)H(3), Z-n-C(4)H(3), E-n-C(4)H(3), i-C(4)H(5), Z-n-C(4)H(5), and E-n-C(4)H(5) to be 119.0, 130.8, 130.8, 78.4, 89.7, and 89.1 kcal mol(-1), respectively. These definitive values remove any remaining uncertainty surrounding the thermochemistry of these isomers in combustion models, allowing for better assessment of whether even-carbon pathways contribute to soot formation. PMID:15527344

  16. Thermochemistry of disputed soot formation intermediates C4H3 and C4H5

    NASA Astrophysics Data System (ADS)

    Wheeler, Steven E.; Allen, Wesley D.; Schaefer, Henry F.

    2004-11-01

    Accurate isomeric energy differences and standard enthalpies of formation for disputed intermediates in soot formation, C4H3 and C4H5, have been determined through systematic extrapolations of ab initio energies. Electron correlation has been included through second-order Z-averaged perturbation theory (ZAPT2), and spin-restricted, open-shell coupled-cluster methods through triple excitations [ROCCSD, ROCCSD(T), and ROCCSDT] utilizing the correlation-consistent hierarchy of basis sets, cc-pVXZ (X=D, T, Q, 5, and 6), followed by extrapolations to the complete basis set limit via the focal point method of Allen and co-workers. Reference geometries were fully optimized at the ROCCSD(T) level with a TZ(2d1f,2p1d) basis set. Our analysis finds that the resonance-stabilized i-C4H3 and i-C4H5 isomers lie 11.8 and 10.7 kcal mol-1 below E-n-C4H3 and E-n-C4H5, respectively, several kcal mol-1 (more, less) than reported in recent (diffusion Monte Carlo, B3LYP density-functional) studies. Moreover, in these systems Gaussian-3 (G3) theory suffers from large spin contamination in electronic wave functions, poor reference geometries, and anomalous vibrational frequencies, but fortuitous cancellation of these sizable errors leads to isomerization energies apparently accurate to 1 kcal mol-1. Using focal-point extrapolations for isodesmic reactions, we determine the enthalpies of formation (ΔfH0∘) for i-C4H3, Z-n-C4H3, E-n-C4H3, i-C4H5, Z-n-C4H5, and E-n-C4H5 to be 119.0, 130.8, 130.8, 78.4, 89.7, and 89.1 kcal mol-1, respectively. These definitive values remove any remaining uncertainty surrounding the thermochemistry of these isomers in combustion models, allowing for better assessment of whether even-carbon pathways contribute to soot formation.

  17. 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…

  18. 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…

  19. Occupational exposure to impulse noise associated with shooting.

    PubMed

    Lwow, Felicja; Jóźków, Paweł; Mędraś, Marek

    2011-01-01

    Shooting training is associated with exposure to a considerable amount of unique noise. We wanted to evaluate noise exposure during such training. Our observations especially apply to professional sport shooters, but they are also valid for shooting coaches/instructors. We collected acoustic signals in 10-, 25- and 50-m as well as open-air shooting ranges. The recorded material was analysed with orthogonal, adaptive parameterization by Shur. The mean duration of a single acoustic signal was 250-800 ms with the C-weighted sound peak pressure level of 138.2-165.2 dB. Shooters may be exposed to as many as 600-1350 acoustic impulses during a training unit. The actual load for the hearing organ of a professional shooter or a shooting coach is ~200 000 acoustic stimuli in a year-long training macrocycle. Orthogonal, adaptive parameterization by Shur makes safe scheduling of shooters' training possible. PMID:21375955

  20. 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

  1. Optoelectronic measures in the analysis of running target shooting.

    PubMed

    Mononen, K; Viitasalo, J T; Era, P; Konttinen, N

    2003-06-01

    In this study, we examined the construct validity and practical significance of an optoelectronic shooting training system (Noptel ST 2000 Sport) for the technical analysis of running target shooting. A total of 37 male shooters of three different skill levels participated in the study. Principal component analysis revealed four common factors of 16 variables describing the aiming trajectory of the rifle barrel: (i) Holding area, (ii) Accuracy of aiming, (iii) Cleanness of triggering and (iv) Time on target. These factors were suggested to describe the essential components of running target shooting. According to the discriminant analysis, the shooters of various skill levels seemed to discriminate successfully into three groups when the aiming trajectory data were analysed. Finally, the aiming trajectory variables represented a 43% of the total variance in the shooting score. In summary, the present data indicated that the optoelectronic shooting training system had practical significance and supported the technical analysis of rifle barrel movement in running target shooting. A sub-set of variables, which reflect the essential information of running target shooting performance, were outlined for training and coaching purposes.

  2. Mechanism of shoot gravitropism

    NASA Technical Reports Server (NTRS)

    Rayle, D. L.

    1984-01-01

    A better understanding of the cellular basis of plant shoot gravitropism was sought. A critical evaluation of the role of auxin gravitropism was provided. An alternative hypothesis which links Ca(42) fluxes to the asymmetric growth that leads to gravicurvature was evaluated.

  3. 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…

  4. 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…

  5. Experimental study of visual training effects in shooting initiation.

    PubMed

    Quevedo, Lluïsa; Solé, Joan; Palmi, Joan; Planas, Antoni; Soana, Carlos

    1999-01-01

    INTRODUCTION: The present study was conducted to investigate the influence of specific visual training in shooting initiation performance. METHODS: Seventy-one first-year university students were divided randomly into two groups. The experimental group followed a nine-session shooting training program that included technical, physical and psychological components, along with specific visual exercises. The control group followed the same program with one difference: this group received theoretical lectures on psychological training techniques instead of doing visual exercises. Pre- and post-test results were obtained for shooting, concentration, saccades and visual acuity. RESULTS: Statistical analysis indicated significant gains in the four mentioned variables for the experimental group. The control group also showed significant differences in the three first variables but no significant improvement in visual acuity. No significant differences in shooting performance were observed between groups. CONCLUSIONS: The effect of vision training on sports initiation performance is still not clear. It cannot be assumed that the improvement is transferable to the performance of precision shooting at the stage of sports initiation.

  6. CPR: Purposeful Action. Putting New Life into 4-H.

    ERIC Educational Resources Information Center

    Jones, Deborah A.; Smith, William C.

    1988-01-01

    In Ohio, 4-H professionals found that it is necessary to conduct market research to have an effective program. Cardiopulmonary resuscitation (CPR) training has been successful in strengthening the 4-H position in the marketplace. (JOW)

  7. 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…

  8. 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…

  9. 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…

  10. 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…

  11. 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

  12. 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.

  13. Sports Writing.

    ERIC Educational Resources Information Center

    Grubaugh, Karl

    2003-01-01

    Lists the following 10 tips for improved sports writing in high school publications: reporting comes before writing; do not try to do too much; show, do not tell; do not do game stories; avoid cliches; avoid "jock-talk"; use the drama of sports; do not write the obvious story; sports is also news; and read great sports writing. (PM)

  14. Why 4-H Members Leave: A Study of Discontinuance through Both Current 4-H Members and Former Members

    ERIC Educational Resources Information Center

    Chilek, Kevin Dwayne

    2012-01-01

    4-H members quit. It is part of every 4-H program, and according to the research, it is even part of growing up. If only we knew why they quit, we could possibly do something about it. To date, the reasons youth join 4-H have been more thoroughly researched than the reasons they quit. This study explores why youth choose to discontinue membership…

  15. The endodermis and shoot gravitropism

    PubMed

    Tasaka, M; Kato, T; Fukaki, H

    1999-03-01

    Shoots and roots of higher plants exhibit negative and positive gravitropism, respectively. A variety of gravitropic mutants have recently been isolated from Arabidopsis, the characterization of which demonstrates that the molecular mechanisms of the gravitropic responses in roots, hypocotyls and inflorescence stems are different. The cytological and molecular analysis of two mutants, shoot gravitropism 1 (sgrl), which is allelic to scarecrow (scr), and sgr7, which is allelic to short-root(shr), indicate that the endodermis is the site of gravity perception in shoots. These data suggest a new model for shoot gravitropism.

  16. 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…

  17. Embracing Scientific and Engineering Practices in 4-H

    ERIC Educational Resources Information Center

    Worker, Steven M.

    2013-01-01

    The 4-H Science Initiative has renewed efforts to strengthen 4-H programmatic and evaluation efforts in science and engineering education. A fundamental component of this initiative is to provide opportunities to youth to aid in their development of science process skills; however, emerging research stresses the importance of engaging youth in…

  18. 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…

  19. 4-H Participation and Science Interest in Youth

    ERIC Educational Resources Information Center

    Heck, Katherine; Carlos, Ramona M.; Barnett, Cynthia; Smith, Martin H.

    2012-01-01

    The study reported here investigated the impacts of participation in 4-H on young people's interest and participation in science. Survey data were collected from relatively large and ethnically diverse samples of elementary and high school-aged students in California. Results indicated that although elementary-grade 4-H members are not more…

  20. 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

  1. 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.

  2. 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…

  3. 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 ...

  4. Sports Safety

    MedlinePlus

    Playing sports can be fun, but it can also be dangerous if you are not careful. You can help ... you are healthy before you start playing your sport Wearing the right shoes, gear, and equipment Drinking ...

  5. 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…

  6. [Sports injuries of the nervous system].

    PubMed

    Lang, C; Stefan, H

    1999-08-01

    Almost 1% of all Germans suffer sports injuries each year, almost 5% of all peripheral nerve lesions are due to sports. A review is given on various activities detailing the specific risks for traumata of the central and peripheral nervous system. Specifically these are volleyball, handball, basketball, American football, soccer, bowling, hockey, baseball, tennis, golf, javelin, fencing, wrestling, judo, boxing, running, jumping, dancing, mountain climbing, weight lifting, gymnastics, horse-back riding, swimming, rowing, skiing, skating, shooting, (motor) biking, car racing, flying, and sports for the disabled. The knowledge of typical traumata should enable the neurologist to rapidly and reliably recognize related lesions and to contribute to their prevention or improvement.

  7. 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.

  8. 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 colliding against…

  9. Properties of homoepitaxial 4H-SiC and characteristics of Ti/4H-SiC Schottky barrier diodes

    NASA Astrophysics Data System (ADS)

    Chen, G.; Li, Z. Y.; Bai, S.; Han, P.

    2008-02-01

    This paper describes the properties of the homoepitaxial 4H-SiC layer, the fabrication and electrical parameters of Ti/4H-SiC Schottky barrier diode (SBD). The 4H-SiC epitaxial layers, grown on the commercially available 8°off-oriented Si-face(0001) single-crystal 4H-SiC wafers, have been performed at 1550~1600°C by using the step controlled epitaxy with low pressure chemical vapor deposition. X-ray diffraction measurement result indicates the single crystal nature of the epilayer, and Raman spectrum shows the typical 4H-SiC feature peaks. When the off-oriented angle of substrate is 8°, the epitaxial growth perfectly replicates the substrate's polytype. High quality 4H-SiC epilayer has been generated on the 4H-SiC substrate. Ti/4H-SiC SBDs with blocking voltage 1kV have been made on an undoped epilayer with 12um in thick and 3×10 15cm -3 in carrier density. The ideality factor n=1.16 and the effective barrier height φ e=0.9V of the Ti/4H-SiC SBDs are measured with method of forward density-voltage (J-V). The diode rectification ratio of forward to reverse (defined at +/-1V) is over 10 7 at room temperature. By using B + implantation, an amorphous layer as the edge termination is formed. The SBDs have on-state current density of 200A/cm2 at a forward voltage drop of about 2V. The specific on-resistance for the rectifier is found to be as 6.6mΩ•cm2.

  10. [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.

  11. [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.

  12. Isomer Energy Differences for the C4H3 and C4H5 Isomers UsingDiffusion Monte Carlo

    SciTech Connect

    Domin, D.; Lester Jr., W.A.; Whitesides, R.; Frenklach, M.

    2007-12-01

    A new diffusion Monte Carlo study is performed on the isomers of C{sub 4}H{sub 3} and C{sub 4}H{sub 5} emulating the methodology of a previous study [Int. J. Chem. Kinetics 33, 808 (2001)]. Using the same trial wave function form of the previous study, substantially different isomerization energies were found owing to the use of larger walker populations in the present work. The energy differences between the E and I isomers of C{sub 4}H{sub 3} were found to be 10.5 {+-} 0.5 kcal/mol and for C{sub 4}H{sub 5}, 9.7 {+-} 0.6 kcal/mol. These results are in reasonable accord with recent MRCI and CCSD(T) findings.

  13. 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. PMID:25448268

  14. 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.

  15. Electronic spectra of C4H3Cl+ isomers

    NASA Astrophysics Data System (ADS)

    Chakrabarty, S.; Rudnev, V.; Fulara, J.; Dietsche, R.; Nagy, A.; Garkusha, I.; Mazzotti, F. J.; Rice, C. A.; Maier, J. P.

    2012-12-01

    Two experimental methods were applied to identify the structure and electronic transitions of C4H3Cl+ isomers. The first is a direct absorption technique where mass-selected ions are embedded in 6 K neon matrices using a mass-selected ion beam and absorption spectra of different C4H3Cl+ isomers were thus observed. The second is a gas phase method on ions which have been collisional cooled with cryogenic helium inside of a 22-pole ion trap. The c-type (1)2 A‧ ← X 2 A″ electronic transition of a C4H3Cl+ isomer could then be measured by a one-colour, two-photon technique at 20 and 50 K in the gas phase. The two sets of data, complemented by calculated excitation energies, allowed the assignment of particular isomers. Rotational structure in the gas phase spectra was resolved for C4H3 35Cl+ and C4H3 37Cl+ isomers of cis-1-chlorobutenynylium. The analysis leads to the spectroscopic constants: T 00 = 19 184.680(5), ? , ? , ? , ? , ? and ? (all in cm-1).

  16. On the Ionization Energies of C4H3 Isomers

    SciTech Connect

    Kaiser, Ralf I.; Mebel, Alexander; Kostko, Oleg; Ahmed, Musahid

    2009-09-16

    We have conducted a combined experimental and theoretical study on the formation of distinct isomers of resonantly stabilized free radicals, C4H3, which are important intermediates in the formation of polycyclic aromatic hydrocarbons in combustion flames and possibly in the interstellar medium. Our study utilized laser ablation of graphite in combination with seeding the ablated species in neat methylacetylene gas which also acted as a reagent. Photoionization efficiency (PIE) curves were recorded of the C4H3 isomers at the Advanced Light Source from 8.0 to 10.3 eV. The experimental PIE curve was compared with theoretical ones suggesting the formation of four C4H3 radicals: two acyclic structures i-C4H3 [1] and E/Z-n-C4H3 [2E/2Z]and two cyclic isomers 3 and 4. These molecules are likely formed via an initial addition of ground state carbon atoms to the carbon-carbon triple bond of the methylacetylene molecule followed by isomerization via hydrogen migrations and ring opening and emission of atomic hydrogen from these intermediates.

  17. Density Functional Exploration of C4H3N Isomers.

    PubMed

    Custer, Thomas; Szczepaniak, Urszula; Gronowski, Marcin; Fabisiewicz, Emilia; Couturier-Tamburelli, Isabelle; Kołos, Robert

    2016-07-28

    Molecules having C4H3N stoichiometry are of astrophysical interest. Two of these, methylcyanoacetylene (CH3C3N) and its structural isomer allenyl cyanide (H2CCCHN), have been observed in interstellar space, while several more have been examined in laboratories. Here we describe, for a broad range of C4H3N isomers, density functional calculations (B3LYP/aug-cc-pVTZ) of molecular parameters including the energetics, geometries, rotational constants, electric dipole moments, polarizabilities, vibrational IR frequencies, IR absorption intensities, and Raman activities. Singlet-triplet splittings as well as singlet vertical electronic excitation energies are given for selected species. The identification of less stable C4H3N molecules, generated in ongoing spectroscopic experiments, relies heavily on these quantum chemical predictions. PMID:27341606

  18. 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. PMID:22639498

  19. 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

  20. British game shooting in transition, 1900-1945.

    PubMed

    Martin, John

    2011-01-01

    This article explores the transformation of lowland game shooting from its heyday in the late Victorian and Edwardian periods to state-imposed rationalization during the Second World War. It evaluates the extent to which the interwar years constituted a period of depression or regeneration in the way the activity was organized and pursued, followed by an in-depth analysis of the impact of the Second World War. The study shows that the prevailing wisdom about the reasons for the decline of game shooting merits reappraisal, particularly in view of the unprecedented changes to the sport that resulted from the government's control and direction of food production during World War II. PMID:21568124

  1. 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…

  2. 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…

  3. 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…

  4. "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)

  5. 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…

  6. 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…

  7. 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…

  8. Marketing Strategies for Recruiting 4-H Members in West Virginia.

    ERIC Educational Resources Information Center

    Wingenbach, Gary J.; Nestor, Cheryl; Lawrence, Layle D.; Gartin, Stacy A.; Woloshuk, Jean; Mulkeen, Patricia

    2000-01-01

    According to a survey of 174 West Virginia 4-H members aged 13-18, the Internet and word of mouth were most effective in recruiting new members. Active messages stressing camps, fun, and friendship had the most influence on retention. A statewide marketing plan was recommended. (SK)

  9. 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, background information,…

  10. Folkpatterns 4-H Leader's Guide: A Cultural Heritage Project.

    ERIC Educational Resources Information Center

    Kozma, LuAnne Gaykowski

    Folkpatterns is a 4-H program in which young people investigate folklore, cultural traditions, and local history. These materials include a leader's guide and Folkpatterns activities. The leader's guide provides information for leading a Folkpatterns project and 12 sample meeting plans to be used with Folkpatterns members or to be adapted for use…

  11. 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…

  12. Self-Protection: A New Approach to 4-H Health.

    ERIC Educational Resources Information Center

    Wright, Sharon K. B.

    This document introduces the issue of self-protection as the Minnesota 4-H Youth Development response to self-destructive behavior among adolescents. It presents findings from a statewide survey of over 36,000 secondary school students using the Minnesota Adolescent Health Survey. Responses are given in the areas of health, school attitudes,…

  13. The Evaluation Attitudes and Practices of 4-H Educators

    ERIC Educational Resources Information Center

    Lekies, Kristi S.; Bennett, Amanda M.

    2011-01-01

    Extension educators are expected to conduct program evaluation. An Internet survey was sent to county 4-H educators in Ohio to examine their evaluation attitudes and practices, as well as barriers to conducting evaluation. Respondents indicated a range of attitudes about evaluation and limited use of different designs and methods. Having enough…

  14. 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…

  15. 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…

  16. [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. PMID:27544982

  17. Teaching Sport as History, History through Sport

    ERIC Educational Resources Information Center

    Wheeler, Robert F.

    1978-01-01

    Describes an undergraduate history course based on two themes: sport as a reflection of society and sport as a socializing agent affecting society. The course focuses on sports and industrialization, traditional and modern sports, political and economic aspects of sport, and inequality and discrimination in sports. (Author/JK)

  18. Rifle-balancing in precision shooting: behavioral aspects and psychophysiological implication.

    PubMed

    Konttinen, N; Lyytinen, H; Viitasalo, J

    1998-04-01

    This study investigated sharpshooters' strategies to control their rifle stability during the aiming period. Six elite and six pre-elite shooters completed a simulated realistic shooting task (laser rifle), and their performance was evaluated from behavioral and psychophysiological perspectives. The analysis of the rifle's barrel movement, indexing the shooter's behavioral performance, supported the view that rifle-balancing is an essential determinant of superior shooting performance. The psychophysiological data, i.e. the brain slow potentials, suggested that the shooters applied different rifle-hold strategies; the elite shooters concentrated primarily on achieving a stable rifle position using psychomotor regulation, whereas the pre-elite shooters were more reliant on the visual-spatial processing. The present study has implications for the understanding of psychological aspects in competitive precision shooting, as well as for the evaluation of the functional significance of the electrocortical slow potentials in shooting-like closed-skill sports.

  19. 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 ...

  20. 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 Diabetic Athlete"; (8) "Pinning Down Your Optimal Weight"; (9)…

  1. Sports Supplements

    MedlinePlus

    ... specialist. The doc will be able to offer alternatives to supplements based on your body and sport. Reviewed by: Mary L. Gavin, MD Date reviewed: January 2015 previous 1 • 2 • 3 For Teens For Kids For Parents MORE ON THIS TOPIC Sports Center Energy Drinks and Food Bars: Power or Hype? A ...

  2. 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)

  3. 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…

  4. 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…

  5. 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…

  6. 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

  7. School Shootings as Organizational Deviance.

    ERIC Educational Resources Information Center

    Fox, Cybelle; Harding, David J.

    2005-01-01

    This article argues that rampage school shootings in American public schools can be understood as instances of organizational deviance, which occurs when events created by or in organizations do not conform to an organization's goals or expectations and produce unanticipated and harmful outcomes. Drawing on data from qualitative case studies of…

  8. 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…

  9. 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.…

  10. 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…

  11. Sports Fitness

    MedlinePlus

    ... motivator. Physically, you need strength and endurance. Your training will vary with your sport. You would not ... for swimming. You might, however, cross train. Cross training simply means that you include a variety of ...

  12. 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)

  13. Team Sports

    MedlinePlus

    ... played for almost seventy years, originated by World War II vets in rehab on the East and ... with a physical disability. Activities include winter skiing, water sports, summer and winter competitions, fitness and special ...

  14. 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...

  15. 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...

  16. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 8 2011-10-01 2011-10-01 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. 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...

  18. 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...

  19. 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.…

  20. Sports and Concussions

    MedlinePlus

    ... of all sports, not just contact sports like football and hockey. As long as people play sports, ... sports, such as: helmet-to-helmet tackles in football getting checked against the boards in hockey heading ...

  1. Patterns of photoassimilate translocation to reproductive shoots from adjacent shoots in Camellia sasanqua by manipulation of sink-source balance between the shoots.

    PubMed

    Oitate, Hiroki; Noguchi, Ko; Sone, Kosei; Terashima, Ichiro; Suzuki, Alata Antönio

    2011-01-01

    To know to what extent reproductive shoots are autonomous in Camellia sasanqua, we manipulated the sink-source balance between the reproductive shoots and their adjacent shoots by selecting vegetative or reproductive adjacent shoots, or defoliating the reproductive shoots, and photosynthetically labeled adjacent shoots with (13)C. The atom% of (13)C did not increase in the unlabeled shoots that had leaves, whereas that in the defoliated, unlabeled shoot was significantly increased. These results indicated that the pattern of translocation of photoassimilates to adjacent reproductive shoots occurs depending on the sink-source balance between shoots. PMID:20574679

  2. BRX promotes Arabidopsis shoot growth.

    PubMed

    Beuchat, Julien; Scacchi, Emanuele; Tarkowska, Danuse; Ragni, Laura; Strnad, Miroslav; Hardtke, Christian S

    2010-10-01

    • BREVIS RADIX (BRX) has been identified through a loss-of-function allele in the Umkirch-1 accession in a natural variation screen for Arabidopsis root growth vigor. Physiological and gene expression analyses have suggested that BRX is rate limiting for auxin-responsive gene expression by mediating cross-talk with the brassinosteroid pathway, as impaired root growth and reduced auxin perception of brx can be (partially) rescued by external brassinosteroid application. • Using genetic tools, we show that brx mutants also display significantly reduced cotyledon and leaf growth. • Similar to the root, the amplitude and penetrance of this phenotype depends on genetic background and shares the physiological features, reduced auxin perception and brassinosteroid rescue. Furthermore, reciprocal grafting experiments between mutant and complemented brx shoot scions and root stocks suggest that the shoot phenotypes are not an indirect consequence of the root phenotype. Finally, BRX gain-of-function lines display epinastic leaf growth and, in the case of dominant negative interference, increased epidermal cell size. Consistent with an impact of BRX on brassinosteroid biosynthesis, this phenotype is accompanied by increased brassinosteroid levels. • In summary, our results demonstrate a ubiquitous, although quantitatively variable role of BRX in modulating the growth rate in both the root and shoot.

  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. 4H-SiC detectors for ultraviolet light monitoring

    NASA Astrophysics Data System (ADS)

    Mazzillo, M.; Sciuto, A.; Badalà, P.; Carbone, B.; Russo, A.; Coffa, S.

    2015-02-01

    Silicon Carbide (SiC) provides the unique property of near-perfect visible blindness and very high signal-to-noise ratio due to the high quantum efficiency and low dark current even at high temperature. These features make SiC the best available material for the manufacturing of visible blind semiconductor ultraviolet (UV) light detectors. Thanks to their properties, SiC detectors have been extensively used in fact for flame detection monitoring, UV sterilization and astronomy. Here we report on the electrical and optical performance of patterned thin metal film NiSi/4H-SiC vertical Schottky photodiodes with different semiconductor exposed area suitably designed for UV light monitoring.

  5. Experimental investigations of the hypernucleus Λ4H

    NASA Astrophysics Data System (ADS)

    Achenbach, P.; Schulz, F.; Aulenbacher, S.; Beričič, J.; Bleser, S.; Böhm, R.; Bosnar, D.; Correa, L.; Distler, M. O.; Esser, A.; Fonvieille, H.; Friščić, I.; Fujii, Y.; Fujita, M.; Gogami, T.; Kanda, H.; Kaneta, M.; Kegel, S.; Kohl, Y.; Kusaka, W.; Margaryan, A.; Merkel, H.; Mihovilovič, M.; Müller, U.; Nagao, S.; Nakamura, S. N.; Pochodzalla, J.; Sanchez Lorente, A.; Schlimme, B. S.; Schoth, M.; Sfienti, C.; Širca, S.; Steinen, M.; Takahashi, Y.; Tang, L.; Thiel, M.; Tsukada, K.; Tyukin, A.; Weber, A.

    2016-03-01

    Negatively charged pions from two-body decays of stopped Λ4H hypernuclei were studied in 2012 at the Mainz Microtron MAMI, Germany. The momenta of the decay-pions were measured with unprecedented precision by using high-resolution magnetic spectrometers. A challenge of the experiment was the tagging of kaons from associated K+∧ production off a Be target at very forward angles. In the year 2014, this experiment was continued with a better control of the systematic uncertainties, with better suppression of coincident and random background, improved particle identification, and with higher luminosities. Another key point of the progress was the improvement in the absolute momentum calibration of the magnetic spectrometers.

  6. 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.

  7. Intergenerational Panels at Centennial Events: Stimulating Discussion about Continuity and Change in the 4-H Program

    ERIC Educational Resources Information Center

    Kaplan, Matthew S.; Weikert, Ben; Scholl, Jan; Rushton, Mya

    2013-01-01

    This article introduces an intergenerational strategy for organizations planning centennial celebratory events. The methods and findings from the 4-H through the Generations session conducted at the joint 4-H Leadership Conference and 4-H Leaders Forum to celebrate the Pennsylvania 4-H Centennial are reported. Youth and adult participants shared…

  8. North Central Region 4-H Volunteers: Documenting Their Contributions and Volunteer Development

    ERIC Educational Resources Information Center

    Nippolt, Pamela Larson; Pleskac, Sue; Schwartz, Vicki; Swanson, Doug

    2012-01-01

    Documenting volunteer contributions strengthens Extension partnerships with volunteers. A team of North Central Region 4-H volunteer specialists collaborated to conduct a study of 4-H volunteer contributions and impacts related to working with youth within the 4-H program. Over three thousand (3,332) 4-H volunteers from throughout the 12-state…

  9. 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…

  10. Sport Progressions.

    ERIC Educational Resources Information Center

    Clumpner, Roy A.

    This book, which is primarily for secondary physical education teachers, presents a sequential approach to teaching skills that are essential to eight sports. The activities and lead-up games included in the book put beginning students directly into game-like situations where they can practice skills. Each chapter begins with a background of the…

  11. 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…

  12. 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)

  13. Racket sports.

    PubMed

    Jayanthi, Neeru; Esser, Stephen

    2013-01-01

    Tennis may be considered a static and dynamic form of exercise with many well-demonstrated health benefits. Tennis has similar rates of injury to other individual recreational sports and junior competitive sports, without the catastrophic risk of contact/collision sports. Classifying tennis players into junior and elite categories versus adult recreational players may help in outlining volume of play recommendations, exposure risk, and types of injuries. Junior and elite players tend to tolerate higher volumes, have more acute and lower extremity injuries, and have more serious overuse stress injuries. Adult recreational players tend to tolerate lower volumes, have more overuse and upper extremity injuries, and more conditions that are degenerative. Many tennis players also develop asymmetric musculoskeletal adaptations, which may increase risk of specific injury. Tennis-specific evaluations may identify these at-risk segments, help guide preventive strategies including technical errors, and assist in developing return-to-play recommendations. Other racket sports such as squash, badminton, and racquetball have less data available but report both acute and traumatic injuries less commonly seen in tennis.

  14. 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.

  15. Self-talk in a basketball-shooting task.

    PubMed

    Theodorakis, Y; Chroni, S; Laparidis, K; Bebetsos, V; Douma, I

    2001-02-01

    This study examined the effectiveness of two different types of self-talk on the performance of a basketball-shooting task. 60 physical education and sports sciences students were organized into one control and two treatment groups which used self-talk. During the experiment, the control group performed with the general instructions, whereas the self-talk groups used the cue-words "relax" and "fast," respectively, Analysis showed that only the participants of the self-talk group who used the word "relax" improved their performance significantly as compared to the other two groups. It appears that self-talk can positively affect performance if its content is appropriate for the task performed.

  16. Sports-specific injuries.

    PubMed

    Plancher, K D; Minnich, J M

    1996-04-01

    Injuries to the upper extremities can happen in any sport. Injury patterns are common to specific sports. Understanding which injuries occur with these sports allows the examiner to diagnose and treat the athlete easily. This article reviews some of the injuries common in sports such as bicycling, golf, gymnastics, martial arts, racquet sports, and weightlifting.

  17. 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. PMID:20528446

  18. 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.

  19. 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)

  20. 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

  1. 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.

  2. 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.

  3. 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…

  4. 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.

  5. 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.

  6. 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...

  7. 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.…

  8. Relationship between Participation in 4-H and Community Leadership in Rural Montana

    ERIC Educational Resources Information Center

    Flynn, Allison; Frick, Martin; Steele, Douglas

    2010-01-01

    Studies on the impact of 4-H on former members generally use alumni as one cohort. In rural states, such as Montana, it is important to understand the impact of 4-H on alumni in these rural areas and the role 4-H plays in community involvement. The study reported here sought to determine the perception of current community leaders in rural Montana…

  9. 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…

  10. 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…

  11. 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…

  12. Text to Speech: A 4-H Model of Accessibility and Inclusion

    ERIC Educational Resources Information Center

    Green, Jeremy W.

    2012-01-01

    4-H project manuals play an integral part in a youth's ability to achieve mastery in a specific project area. For youth who struggle with reading, written 4-H materials prove inadequate in addressing the needs of the learner. This article proposes a new delivery method of 4-H educational material designed to create a more inclusive and…

  13. 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…

  14. Growth and carbohydrate status of coppice shoots of hybrid poplar following shoot pruning.

    PubMed

    Tschaplinski, T J; Blake, T J

    1995-05-01

    Fifteen, 1-year-old Populus maximowiczii Henry x P. nigra L. 'MN9' trees were decapitated and allowed to sprout. After 8 weeks, all had 6 to 10 coppice shoots. All shoots, except the tallest (dominant) shoot, were removed from five of the trees (pruned treatment), and shoot growth, gas exchange and carbohydrate status were compared in the pruned and unpruned trees. Although photosynthetic rate of recently mature leaves of pruned trees was approximately 50% greater than that of leaves on the dominant shoot of unpruned trees, and the dry weight of leaves of pruned trees was 37% greater than that of the leaves on the dominant shoot of unpruned trees, the shoot dry matter relative growth rate did not differ between treatments. Concentrations of water-soluble carbohydrates and starch in the uppper stem and leaves of the dominant shoot were similar in pruned and unpruned trees. However, relative to that of the dominant shoot in unpruned trees, the lower stem in pruned trees was depleted in both soluble carbohydrates and starch. Starch deposition, assessed as the quantity of (14)C-starch in tissues 24 h after a fully expanded source leaf was labeled with (14)CO(2), was 3.9 times greater in roots of pruned trees than in roots of unpruned trees. We conclude that early removal of all but the dominant shoot reduces the carbohydrate status of the roots and the lower portion of the stem by eliminating the excised shoots as a source of photosynthate.

  15. Sport for All. Low Cost Sports Halls.

    ERIC Educational Resources Information Center

    Council of Europe, Strasbourg (France).

    This report of the conference on low-cost sports halls, sponsored by the Council of Europe, is divided into two sections: technical studies and conclusions. The introduction to the report provides an overview of the long-term program of the Council of Europe with regard to sport for all and a discussion of multipurpose sports halls. Sociocultural,…

  16. Returning to sports after a back injury

    MedlinePlus

    Back injury - returning to sports; Sciatica - returning to sports; Herniated disc - returning to sports; Herniated disk - returning to sports; Spinal stenosis - returning to sports; Back pain - returning ...

  17. 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)

  18. 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…

  19. American Indian Sports Heritage.

    ERIC Educational Resources Information Center

    Oxendine, Joseph B.

    This book chronicles the story of sports among American Indians. Part 1 examines the nature and role of games in traditional Indian life, with five chapters on: Indian concepts of sport; ball games; foot racing; other sports; children's play; and games of chance. Part 2 looks at the emergence of Indians in modern sport, with five chapters on:…

  20. 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…

  1. A method to determine waterfowl shooting distances

    USGS Publications Warehouse

    Davenport, D.A.; Sherwood, G.A.; Murdy, H.W.

    1973-01-01

    Long-range shooting at ducks and geese frequently results in a high crippling loss, unretrieved birds and frustrated hunters. A principal problem has been the general inability of hunters or observers to properly judge distance of birds. This paper describes a reasonably accurate method developed to determine shooting distances to geese. Two observers utilized transit-mounted 4X hunting scopes to determine angles and elevations to goose hunters and birds. These data were used to set up a series of triangles by which a distance between hunter and birds could be calculated. Known-distance tests indicated an average measurement error of approximately two percent. An average shooting distance of 71 yards was calculated from 175 sightings. The maximum range was 240 yards and the minimum was 24 yards. The relationship of shooting to clean kills and crippling loss is also discussed.

  2. 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.

  3. [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.

  4. 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.

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

    PubMed

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

    2015-06-01

    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.

  6. 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

    2015-09-01

    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.

  7. EXTERNAL BARREL TEMPERATURE OF A SMALL BORE OLYMPIC RIFLE AND SHOOTING PRECISION

    PubMed Central

    Gladyszewska, B.; Baranowski, P.; Mazurek, W.; Wozniak, J.

    2013-01-01

    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. PMID:24744465

  8. 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.

  9. 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…

  10. Is movement variability important for sports biomechanists?

    PubMed

    Bartlett, Roger; Wheat, Jon; Robins, Matthew

    2007-05-01

    This paper overviews the importance for sports biomechanics of movement variability, which has been studied for some time by cognitive and ecological motor skills specialists but, until quite recently, had somewhat been overlooked by sports biomechanists. The paper considers biomechanics research reporting inter- and intra-individual movement variability in javelin and discus throwing, basketball shooting, and locomotion. The overview does not claim to be comprehensive and we exclude such issues as the theoretical background to movement and coordination variability and their measurement. We overview evidence, both theoretical and empirical, of inter-individual movement variability in seeking to achieve the same task goal, in contrast to the concept of "optimal" movement patterns. Furthermore, even elite athletes cannot reproduce identical movement patterns after many years of training, contradicting the ideas of motor invariance and "representative" trials. We contend that movement variability, far from being solely due to neuromuscular system or measurement "noise"--as sports biomechanists may have previously supposed--is, or could be, functional. Such functionality could allow environmental adaptations, reduce injury risk, and facilitate changes in coordination patterns. We conclude by recommending that sports biomechanists should focus more of their research on movement variability and on important related topics, such as control and coordination of movement, and implications for practice and skill learning.

  11. Sports dentistry: A review.

    PubMed

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

    2014-12-01

    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.

  12. 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

  13. 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.

  14. 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

  15. A transcranial Doppler sonography study of shoot/don't-shoot responding.

    PubMed

    Schultz, Natasha B; Matthews, Gerald; Warm, Joel S; Washburn, David A

    2009-08-01

    The purpose of this study was to examine the relationship between changes in cerebral blood-flow velocity and performance on a speeded shoot/don't-shoot task. Brain activity as indicated by cerebral blood-flow velocity (hemovelocity) was recorded using the transcranial Doppler ultrasonography. A shoot/don't-shoot decision-making task presented participants with threat/nonthreat stimuli in the form of bull's-eye images of various colors. Participants were required to shoot threat targets using a laser-modified handgun. Results support a vigilance decrement in both the performance measures and hemovelocity. Performance, as measured by reaction time, number of hits, and marksmanship, decreased across the length of the vigil. Hemovelocity slowed across the left and right hemispheres as the task progressed, and hemovelocity was slower in the right hemisphere than in the left hemisphere. PMID:19587168

  16. Monolayer growth modes of Re and Nb on 4H -SiC(0001) and 4H-SiC(0001¯)

    NASA Astrophysics Data System (ADS)

    Bryant, K. W.; Bozack, M. J.

    2005-01-01

    Auger electron spectroscopy (AES) and secondary electron emission have been used to specify the room temperature monolayer adsorption characteristics of Re and Nb on the basal, polar surfaces of 4H -SiC. Measurement of the secondary electron emission current relates the absorbed crystal current to the change in AES peak-to-peak signal intensities for both substrate and adsorbate. For the 4H-SiC(0001) Si-face surface, both metals grow by formation of a single monolayer followed by growth of simultaneous monolayers. For the 4H -SiC(0001¯) C-face surface, both metals grow layer by layer (Frank-van der Merwe). Measurements of the coefficient of attenuation, inelastic mean free path, and coverage versus Auger intensities are also reported.

  17. 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...

  18. 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)…

  19. 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…

  20. The Challenges Associated with Change in 4-H/Youth Development.

    ERIC Educational Resources Information Center

    McKee, Renee K.; Talbert, B. Allen; Barkman, Susan J.

    2002-01-01

    A survey of 97 Indiana 4-H/youth development educators and interviews with staff and volunteer board members indicated that volunteers believe in core 4-H values, recommend reaching more and different youth, and believe that the rural image inhibits progress. Staff interactions with volunteers, lack of parental involvement, group organization and…

  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. 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. PMID:23070917

  3. 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…

  4. 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…

  5. 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…

  6. 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…

  7. 4-H and School-Age Care: A Great Combination! Point of View.

    ERIC Educational Resources Information Center

    Vandenbergh, Barbara D.

    1999-01-01

    Discusses the positive relationship between 4-H programs and school-age care programs, advocating the use of 4-H programs as a model for care, or as a source of care, caregiver training, or curriculum. Notes the role of the Cooperative Extension System in training and supporting school-age care providers. (JPB)

  8. 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…

  9. College Transition Study Shows 4-H Helps Youth Prepare for and Succeed in College

    ERIC Educational Resources Information Center

    Ratkos, Judy; Knollenberg, Lauren

    2015-01-01

    Many young adults enter college without the knowledge and skills necessary to succeed. The purpose of the study reported here was to determine if 4-H helps develop life skills needed for the transition to college and overall college success. An online survey was sent to college-attending 4-H alumni and a comparison group, with a final sample size…

  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. 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…

  12. 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…

  13. 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…

  14. Global 4-H Network: Laying the Groundwork for Global Extension Opportunities

    ERIC Educational Resources Information Center

    Major, Jennifer; Miller, Rhonda

    2012-01-01

    A descriptive study examining 4-H programs in Africa, Asia, and Europe was conducted to provide understanding and direction in the establishment of a Global 4-H Network. Information regarding structure, organizational support, funding, and programming areas was gathered. Programs varied greatly by country, and many partnered with other 4-H…

  15. What Are Sports Injuries?

    MedlinePlus

    ... 06:02 Size: 11.7 MB November 2014 What Are Sports Injuries? Fast Facts: An Easy-to- ... Research Is Being Done on Treating Sports Injuries? What’s the Difference Between an Acute and a Chronic ...

  16. Simple method for the growth of 4H silicon carbide on silicon substrate

    NASA Astrophysics Data System (ADS)

    Asghar, M.; Shahid, M. Y.; Iqbal, F.; Fatima, K.; Nawaz, Muhammad Asif; Arbi, H. M.; Tsu, R.

    2016-03-01

    In this study we report thermal evaporation technique as a simple method for the growth of 4H silicon carbide on p-type silicon substrate. A mixture of Si and C60 powder of high purity (99.99%) was evaporated from molybdenum boat. The as grown film was characterized by XRD, FTIR, UV-Vis Spectrophotometer and Hall Measurements. The XRD pattern displayed four peaks at 2Θ angles 28.550, 32.700, 36.100 and 58.900 related to Si (1 1 1), 4H-SiC (1 0 0), 4H-SiC (1 1 1) and 4H-SiC (2 2 2), respectively. FTIR, UV-Vis spectrophotometer and electrical properties further strengthened the 4H-SiC growth.

  17. 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).

  18. Visual training programme applied to precision shooting.

    PubMed

    Quevedo i Junyent, L; Solé i Fortó, J

    1995-09-01

    A three month visual training programme was conducted at the CAR of Sant Cugat (Olympic Training Center). Eleven members of 'The Catalan Government Special Intervention Squad' were used in a clinical trial. Pre-test and post-test results were obtained for pistol shooting, visual function, and psychological and physical states. Statistical analysis indicated significant gains in visual function and pistol shooting scores after the programme, while psychological (anxiety) and physical condition remained the same. Some conclusive statements can be made with regard to the relation of visual function improvement and shooting performance increment, after analysing the data. This improvement is evident in statistically significant post-test gains in the following variables: 'phoria at distance, recovery points in fusional reserves at distance, analytical amplitude, negative relative accommodation, saccadic fixations, and accommodative facility at distance and at near. The rest of the controlled visual variables also showed clinical improvement.

  19. 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.

  20. 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

  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. 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"…

  3. Sport Education: A Retrospective.

    ERIC Educational Resources Information Center

    Siedentop, Daryl

    2002-01-01

    Provides a history of the development of a curriculum and instruction model called Sport Education (which provides authentic, educationally rich sport experiences in the context of school physical education), reviewing theoretical and practical connections of Sport Education to other curricular and instructional models and exploring issues related…

  4. 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,…

  5. 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

  6. Thermal behavior of the SHOOT gallery arm

    NASA Technical Reports Server (NTRS)

    Nissen, J. A.; Vansciver, Steven W.

    1990-01-01

    The planned Superfluid Helium On-Orbit Transfer (SHOOT) experiment will show the feasibility of resupplying orbiting facilities with liquid helium. The SHOOT experiment, designed for transfer rates of 300 to 800 liters/hr, will use a thermomechanical pump and four screen covered flow channels for fluid acquisition. Cavitation and thermal behavior was examined in ground based tests of the pump and of a full sized channel. A model for estimating the temperature profile at the pump inlet is presented. Large temperature increases in this region can significantly degrade the performance of the fountain pump.

  7. Thermal behavior of the SHOOT gallery arm

    NASA Technical Reports Server (NTRS)

    Nissen, J. A.; Van Sciver, S. W.

    1991-01-01

    The planned Superfluid Helium On-Orbit Transfer (SHOOT) experiment will show the feasibility of resupplying orbiting facilities with liquid helium. The SHOOT experiment, designed for transfer rates of 300 to 800 liters/hr, will use a thermomechanical pump and four screen covered flow channels for fluid acquisition. Cavitation and thermal behavior was examined in ground based tests of the pump and of a full sized channel. A model for estimating the temperature profile at the pump inlet is presented. Large temperature increases in this region can significantly degrade the performance of the fountain pump.

  8. Shoot Tip Culture of Arnica montana for Micropropagation.

    PubMed

    Conchou, O; Nichterlein, K; Vömel, A

    1992-02-01

    Multiple shoots were regenerated from shoot tips of ARNICA MONTANA on MS and B5 media supplemented with BA (1 mg/l) and NAA (0.1 mg/l). Sections of 1-2 mm in length cultured from IN VITRO germinated seedlings regenerated 7.7 (mean) shoots on the MS medium, whereas sections cultured from greenhouse plants regenerated 9.0 (mean) shoots on the B5 medium within 6 weeks. Subsequent subcultures of shoots on the same media but without NAA resulted in similar or lower multiplication rates (1.6 to 3.1 in 3 weeks). Shoot development was promoted, whereas shoot initiation was simultaneously inhibited by the addition of activated charcoal to the media. Rooting was induced by culturing shoots from seedling as well as from greenhouse plant shoot tips on MS or B5 medium supplemented with NAA. The plantlets were transplanted into soil and grown successfully under greenhouse and field conditions.

  9. Shoot or don't shoot? Why police officers are more inclined to shoot when they are anxious.

    PubMed

    Nieuwenhuys, Arne; Savelsbergh, Geert J P; Oudejans, Raôul R D

    2012-08-01

    We investigated the effect of anxiety on police officers' shooting decisions. Thirty-six police officers participated and executed a low- and high-anxiety video-based test that required them to shoot or not shoot at rapidly appearing suspects that either had a gun and "shot," or had no gun and "surrendered." Anxiety was manipulated by turning on (high anxiety) or turning off (low anxiety) a so-called "shootback canon" that could fire small plastic bullets at the participants. When performing under anxiety, police officers showed a response bias toward shooting, implying that they accidentally shot more often at suspects that surrendered. Furthermore, shot accuracy was lower under anxiety and officers responded faster when suspects had a gun. Finally, because gaze behavior appeared to be unaffected by anxiety, it is concluded that when they were anxious, officers were more inclined to respond on the basis of threat-related inferences and expectations rather than objective, task-relevant visual information. PMID:22023363

  10. 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…

  11. American Orthopaedic Society for Sports Medicine

    MedlinePlus

    ... Research Publications Toggle American Journal of Sports Medicine Sports Health: A Multidisciplinary Approach Orthopaedic Journal of Sports Medicine Journal Apps Sports Medicine Update Other Professional ...

  12. 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.

  13. Synthesis and characterization of 4-aryl-4H-chromenes from H-cardanol.

    PubMed

    Rao, Hulluru Surya Prakash; Kamalraj, Mani

    2014-09-01

    We have synthesized and characterized a variety of fat-soluble, low-melting and medicinally useful 4-aryl-4H-chromenes from H-cardanol (side-chain perhydrogenated cardanol, 3-pentadecylphenol), a renewable and low-cost product from locally grown cashew nut trees (Anacardium occidentale L.). We incorporated H-cardanol into the aromatic rings of either 4H-chromene or phenol, or both. Substitution of C4SMe in N-methyl-4-(methylthio)-3-nitro-4H-chromene-2-amines with H-cardanol was regio-specific at the C6 position. PMID:25918806

  14. Using Multiple Youth Programming Delivery Modes to Drive the Development of Social Capital in 4-H Participants

    ERIC Educational Resources Information Center

    Kinsey, Sharon

    2013-01-01

    This article focuses on how 4-H youth participants are building social capital, or connections among individuals and community members, through their 4-H experiences. These experiences can be seen through the lens of such 4-H delivery modes as the traditional 4-H club, after-school programs, and school enrichment programs. In addition, other…

  15. 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.

  16. 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...

  17. Multiple Shoot Tip Cultures in Peas.

    ERIC Educational Resources Information Center

    Smith, Robert A.; And Others

    1997-01-01

    Describes an exercise used as a follow-up activity to a lecture presentation exploring the basic methodology and theory of shoot tip cultures. Utilizes a factorial experimental design which allows for the determination of the effects of each factor alone and in combination with each other. Other concepts emphasized include dependent and…

  18. 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…

  19. 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

  20. 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 Manhattan in New York…

  1. 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.

  2. 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…

  3. 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…

  4. Adolescent mass shootings: developmental considerations in light of the Sandy Hook shooting.

    PubMed

    Rice, Timothy R; Hoffman, Leon

    2015-05-01

    Adolescent mass shootings are a special subset of mass killings, which continue despite significant preventative public health efforts. It is often held that these individuals have few salient warning signs that could have been identified. This piece proposes that mass shootings committed by adolescent and post-adolescent young males must be understood from a developmental perspective. The hypothesis proposed in this paper is that such killings occur as the result of the adolescent's frustrated effort to progress along normative development. The goal of normative separation from maternal figures by the boy is presented as a potential risk factor when this goal is thwarted. Childhood case material from the perpetrator of a recent adolescent mass shooting, the Sandy Hook shooting, is discussed as an illustration of this hypothesis. Implications for public health measures and for individualized treatment are presented and developed.

  5. Reaching Migrant Farmworker Youth through 4-H Career and Workforce Programs.

    ERIC Educational Resources Information Center

    Wille, Celina G.

    1999-01-01

    Migrant-farm-worker youth learned about employment and educational opportunities in agriculture through a 4-H-sponsored conference. The conference was developed by a partnership of university extension, community organizations, schools, and private industry. (SK)

  6. 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.

  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. Fabrication of High-Q Nanobeam Photonic Crystals in Epitaxially Grown 4H-SiC.

    PubMed

    Bracher, David O; Hu, Evelyn L

    2015-09-01

    Silicon carbide (SiC) is an intriguing material due to the presence of spin-active point defects in several polytypes, including 4H-SiC. For many quantum information and sensing applications involving such point defects, it is important to couple their emission to high quality optical cavities. Here we present the fabrication of 1D nanobeam photonic crystal cavities (PCC) in 4H-SiC using a dopant-selective etch to undercut a homoepitaxially grown epilayer of p-type 4H-SiC. These are the first PCCs demonstrated in 4H-SiC and show high quality factors (Q) of up to ∼7000 as well as low modal volumes of <0.5 (λ/n)(3). We take advantage of the high device yield of this fabrication method to characterize hundreds of devices and determine which PCC geometries are optimal. Additionally, we demonstrate two methods to tune the resonant wavelengths of the PCCs over 5 nm without significant degradation of the Q. Lastly, we characterize nanobeam PCCs coupled to luminescence from silicon vacancy point defects (V1, V2) in 4H-SiC. The fundamental modes of two such PCCs are tuned into spectral overlap with the zero phonon line (ZPL) of the V2 center, resulting in an intensity increase of up to 3-fold. These results are important steps on the path to developing 4H-SiC as a platform for quantum information and sensing.

  9. 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

    2016-02-01

    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.

  10. The crystal structure of "green" Cs 2[VOF 4(H 2O)] and its relationship to "blue" Cs 2[VOF 4(H 2O)

    NASA Astrophysics Data System (ADS)

    Mattes, Rainer; Foerster, Harry

    1982-11-01

    Crystals of a second, "green" modification of Cs 2[VOF 4(H 2O)] were obtained from aqueous solution. Their crystal structure was studied on the basis of three-dimensional X-ray data. The structure is orthorhombic, a = 8.231(3), b = 10.323(3), c = 8.497(3) Å, V = 722.0Å 3, Z = 4, space group Ccmm. The final R and RW were 0.035 and 0.048, respectively, for 421 independent reflections. As the already known "blue" modification, the present structure contains isolated, highly deformed octahedral [VOF 4(H 2O)] 2- ions with the oxygen atoms in trans positions. The cesium sublattice and the orientation of the anions to each other are completely different in both modifications. uv/VIS reflection, and ir and Raman spectra of both modifications are discussed.

  11. Fun First! Sports for Kids.

    ERIC Educational Resources Information Center

    Kanters, Michael A.; Tebbutt, Sharon

    2001-01-01

    Outlines the foundation for a new national program, Fun First! Sports for Kids, designed to help grassroots sports leagues work with and get the most out of sport parents, noting that parents have a great impact on a child's sport experience. The article also provides recommendations for actions that sport league administrators can take to…

  12. 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.

  13. How do plant shoots bend up? The initial step to elucidate the molecular mechanisms of shoot gravitropism using Arabidopsis thaliana.

    PubMed

    Fukaki, H; Fujisawa, H; Tasaka, M

    1996-06-01

    In higher plants, shoots show a negative gravitropic response. To elucidate the molecular mechanisms of this phenomenon, mutational analyses using Arabidopsis thaliana are in progress. This minireview aims to present recent developments in the genetic analysis of shoot gravitropism in this organism. We focus mainly on our studies on the novel shoot gravitropic (sgr) mutants in Arabidopsis thaliana that have dramatic defects in shoot gravitropism.

  14. Precision shooting: Sampling long transition pathways

    NASA Astrophysics Data System (ADS)

    Grünwald, Michael; Dellago, Christoph; Geissler, Phillip L.

    2008-11-01

    The kinetics of collective rearrangements in solution, such as protein folding and nanocrystal phase transitions, often involve free energy barriers that are both long and rough. Applying methods of transition path sampling to harvest simulated trajectories that exemplify such processes is typically made difficult by a very low acceptance rate for newly generated trajectories. We address this problem by introducing a new generation algorithm based on the linear short time behavior of small disturbances in phase space. Using this "precision shooting" technique, arbitrarily small disturbances can be propagated in time, and any desired acceptance ratio of shooting moves can be obtained. We demonstrate the method for a simple but computationally problematic isomerization process in a dense liquid of soft spheres. We also discuss its applicability to barrier-crossing events involving metastable intermediate states.

  15. Formation of polarity convergences underlying shoot outgrowths.

    PubMed

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

    2016-08-01

    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.

  16. 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.

  17. Formation of polarity convergences underlying shoot outgrowths.

    PubMed

    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. PMID:27478985

  18. 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…

  19. Confidentiality in Sports Medicine.

    PubMed

    Malcolm, Dominic

    2016-04-01

    This article synthesizes existing literature to provide a summary of the ethical issues concerning patient confidentiality in sport. It outlines the medical principle of confidentiality and identifies cross-cultural ethicolegal variations that shape its implementation. Clinicians' multiple obligations, physical environments, and practice and policy contexts are discussed, and research detailing experiences of maintaining patient confidentiality in sport is reviewed. Policy recommendations for enhancing compliance with this ethical principle are summarized. It is argued that the context of sport exacerbates pressures on clinicians to break patient confidentiality, breaches occur regularly, and interventions are required to enhance ethical compliance in sports medicine.

  20. Catastrophic pediatric sports injuries.

    PubMed

    Luckstead, Eugene F; Patel, Dilip R

    2002-06-01

    The high school sports of wrestling, gymnastics, ice hockey, baseball, track, and cheerleading should receive closer attention to prevent injury. Safer equipment and sport-specific conditioning should be provided and injuries strictly monitored. Greater attention must also be paid to swimming and diving techniques, and continued observation is needed for heat stroke and heat intolerance in sports such as football, wrestling, basketball, track and field, and cross-country. An increased awareness of commotio cordis in sports other than baseball should include ice hockey, football, track field events, and lacrosse. American football because of the sheer numbers and associated catastrophic injury potential must continue to be monitored at the highest medical levels!

  1. Chlordecone Transfer and Distribution in Maize Shoots.

    PubMed

    Pascal-Lorber, Sophie; Létondor, Clarisse; Liber, Yohan; Jamin, Emilien L; Laurent, François

    2016-01-20

    Chlordecone (CLD) is a persistent organic pollutant (POP) that was mainly used as an insecticide against banana weevils in the French West Indies (1972-1993). Transfer of CLD via the food chain is now the major mechanism for exposure of the population to CLD. The uptake and the transfer of CLD were investigated in shoots of maize, a C4 model plant growing under tropical climates, to estimate the exposure of livestock via feed. Maize plants were grown on soils contaminated with [(14)C]CLD under controlled conditions. The greatest part of the radioactivity was associated with roots, nearly 95%, but CLD was detected in whole shoots, concentrations in old leaves being higher than those in young ones. CLD was thus transferred from the base toward the plant top, forming an acropetal gradient of contaminant. In contrast, results evidenced the existence of a basipetal gradient of CLD concentration within leaves whose extremities accumulated larger amounts of CLD because of evapotranspiration localization. Extractable residues accounted for two-thirds of total residues both in roots and in shoots. This study highlighted the fact that the distribution of CLD contamination within grasses resulted from a conjunction between the age and evapotranspiration rate of tissues. CLD accumulation in fodder may be the main route of exposure for livestock. PMID:26701746

  2. 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,…

  3. 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.

  4. 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.

  5. Self-assembly of C4H-type hydrogenated graphene.

    PubMed

    Liu, Zilong; Xue, Qingzhong; Xing, Wei; Du, Yonggang; Han, Zhide

    2013-11-21

    We demonstrate by molecular dynamic (MD) simulations that patterned partially hydrogenated graphene (C4H) can self-assemble at room temperature. The main driving force of the self-assembly of C4H is due to the one-sided distribution of hydrogen and the corresponding asymmetric orientation of sp(3) bonding, there exists strong electrostatic repulsion between the relatively close H atoms. The simulations show that C4H can self-assemble into various carbon nanoscroll (CNS) structures, this is mainly controlled by its geometry (size and aspect ratio). And the carbon nanotube (CNT) is a good candidate to activate and guide C4H to form CNS, whose core size can be controlled. Meanwhile, a novel CNT/C4H core/shell composite nanostructure is also formed. The theoretical results shed important light on a feasible approach to fabricate high-quality CNS and other novel nanostructures including core/shell structures, which hold great potential applications in optics, optoelectronic devices, hydrogen storage, sensors, and energy storage in supercapacitors or batteries. PMID:24064528

  6. Existence of {sub {lambda}}{sub {lambda}}{sup 4}H: A variational Monte Carlo search

    SciTech Connect

    Shoeb, Mohammad

    2005-02-01

    A variational Monte Carlo (VMC) calculation for the binding energy B{sub {lambda}}{sub {lambda}} of the lightest hypernucleus {sub {lambda}}{sub {lambda}}{sup 4}H has been performed in the four-body {lambda}{lambda}pn model. A range of input {lambda}{lambda} potentials of moderate strength produce a particle-stable {sub {lambda}}{sub {lambda}}{sup 4}H for the simulated NSC97e and f {lambda}N potentials, whereas the phenomenological Minnesota {lambda}N potential needs a much stronger {lambda}{lambda} potential to bind. The VMC results for B{sub {lambda}}{sub {lambda}} agree with the prediction of the stochastic variational model but contradict the recent Faddeev-Yakubovsky calculation. As reported earlier, B{sub {lambda}}{sub {lambda}} is sensitive to the triplet {lambda}N channel for a given {lambda}{lambda} potential. The B{sub {lambda}}{sub {lambda}} of {sub {lambda}}{sub {lambda}}{sup 4}H in the three-body {lambda}{lambda}d cluster model is consistent with but slightly lower than the Faddeev calculation. The VMC method predicts a stable {sub {lambda}}{sub {lambda}}{sup 4}H system in both models and thus offers the possibility of identifying {sub {lambda}}{sub {lambda}}{sup 4}H in a future extension of E906 or of a related experiment at KEK, provided the simulated potentials are true representations of realistic Nijmegen potentials.

  7. CVD Growth of 3C-SiC on 4H/6H Mesas

    SciTech Connect

    Neudeck,P.; Trunek, A.; Spry, D.; Powell, J.; Du, H.; Skowronski, M.; Huang, X.; Dudley, M.

    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 (HRXRD) and high resolution cross-sectional transmission electron microscopy (HRXTEM) 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.

  8. 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.

  9. Nickel ohmic contacts of high-concentration P-implanted 4H-SiC

    NASA Astrophysics Data System (ADS)

    Chunjuan, Liu; Su, Liu; Jingjing, Feng; Rong, Wu

    2012-03-01

    Different-dose phosphorus ion implantation into 4H-SiC followed by high-temperature annealing was investigated. AlN/BN and graphite post-implantation annealing for ion-implanted SiC at 1650 °C for 30 min was conducted to electrically activate the implanted P+ ions. Ni contacts to the P+-implanted 4H-SiC layers were examined by transmission line model and Hall measurements fabricated on P-implanted (0001). The results indicated that a high-quality ohmic contact and specific contact resistivity of 1.30 × 10-6 Ω · cm2 was obtained for the P+-implanted 4H-SiC layers. The ρC values of the Ni-based implanted layers decreased with increasing P doping concentrations, and a weaker temperature dependence was observed for different samples in the 200-500 K temperature range.

  10. Transition to non-toxic gunshot use in Olympic shooting: policy implications for IOC and UNEP in resolving an environmental problem.

    PubMed

    Thomas, Vernon George; Guitart, Raimon

    2013-10-01

    Olympic shooters discharge, annually, thousands of tons of lead shot which pose toxic risks to animals and may pollute both surface and ground waters. Non-toxic steel shot is an acceptable and effective substitute, but International Shooting Sports Federation (ISSF) rules prevent its adoption. The present policy and rules of the ISSF on lead shot use contravene the International Olympic Committee (IOC) Charter position on environmental protection. The United Nations Environment Programme (UNEP), a formal Olympic partner on environmental protection, has no stated policy on contamination from lead ammunition, despite having declared lead a Priority Area for remedial action, and is pressing to remove lead from the global human environment. The IOC Sport and Environment Commission and UNEP could examine the continued use of lead shot ammunition and advise the IOC Executive Board on appropriate changes in policy and rules that could halt the massive lead shot contamination of shooting range environments world-wide. PMID:23529514

  11. Transition to non-toxic gunshot use in Olympic shooting: policy implications for IOC and UNEP in resolving an environmental problem.

    PubMed

    Thomas, Vernon George; Guitart, Raimon

    2013-10-01

    Olympic shooters discharge, annually, thousands of tons of lead shot which pose toxic risks to animals and may pollute both surface and ground waters. Non-toxic steel shot is an acceptable and effective substitute, but International Shooting Sports Federation (ISSF) rules prevent its adoption. The present policy and rules of the ISSF on lead shot use contravene the International Olympic Committee (IOC) Charter position on environmental protection. The United Nations Environment Programme (UNEP), a formal Olympic partner on environmental protection, has no stated policy on contamination from lead ammunition, despite having declared lead a Priority Area for remedial action, and is pressing to remove lead from the global human environment. The IOC Sport and Environment Commission and UNEP could examine the continued use of lead shot ammunition and advise the IOC Executive Board on appropriate changes in policy and rules that could halt the massive lead shot contamination of shooting range environments world-wide.

  12. 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.

  13. 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

  14. Anti-reflective nano- and micro-structures on 4H-SiC for photodiodes

    PubMed Central

    2011-01-01

    In this study, nano-scale honeycomb-shaped structures with anti-reflection properties were successfully formed on SiC. The surface of 4H-SiC wafer after a conventional photolithography process was etched by inductively coupled plasma. We demonstrate that the reflection characteristic of the fabricated photodiodes has significantly reduced by 55% compared with the reference devices. As a result, the optical response Iillumination/Idark of the 4H-SiC photodiodes were enhanced up to 178%, which can be ascribed primarily to the improved light trapping in the proposed nano-scale texturing. PMID:21711744

  15. Crystal and molecular structure of 2,4,4-trisubstituted 5-amino-4 H-imidazoles

    NASA Astrophysics Data System (ADS)

    Bellanato, J.; Avendaño, C.; Ramos, M. T.; Smith-Verdier, P.; Florencio, F.; Garcia-Blanco, S.

    Three 5-amino-4 H-imidazole derivatives 2(2-pyridyl) and 2-ethoxycarbonyl-4,4-pentamethylene-5-amino-and 2(2-pyridyl)-4,4-dimethyl-5(2-pyridylamino)4 H-imidazoles have been studied by i.r. and Raman spectroscopy. The crystal structure of one has been determined by X-ray diffraction. The tautomeric amino-imino equilibrium in different working conditions is also studied from spectroscopic data. The amino and the unconjugated imino forms are characterized.

  16. Estimation of negative ions in VHF SiH4/H2 plasma

    NASA Astrophysics Data System (ADS)

    Yamane, Tsukasa; Nakano, Shinya; Nakao, Sachiko; Takeuchi, Yoshiaki; Ichiki, Ryuta; Muta, Hiroshi; Uchino, Kiichiro; Kawai, Yoshinobu

    2014-11-01

    The characteristics of a VHF SiH4/H2 plasma (frequency: 60 MHz) at high pressures were examined as a function of silane concentration with a heated Langmuir probe. Anomalous reductions in electron saturation current were observed, suggesting the existence of many negative ions. An estimation of the concentration of negative ions was attempted using the sheath theory including negative ions. It was found that there exist H- and SiH3- ions as dominant negative ions in the VHF SiH4/H2 plasma. In addition, the measured floating potential agreed with the theoretical value.

  17. 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.

  18. 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…

  19. 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…

  20. Listening to Sports Idioms.

    ERIC Educational Resources Information Center

    Wirkus, Tom; Bohlken, Bob

    In the book, "Talking from 9 to 5," Deborah Tannen suggests that females have difficulty listening to males in the workplace because of the masculine inclination to talk sports the majority of the time. Men use sports idioms, metaphors, and cliches, making business a "peculiar language" which excludes "naive" listeners, females. To test the…

  1. 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.

  2. 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 political…

  3. 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…

  4. 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…

  5. 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…

  6. Superstition in Sport.

    ERIC Educational Resources Information Center

    Gregory, C. Jane; Petrie, Brian M.

    The introduction of this investigation into superstitions of athletes reviews past research on the subject. It is stated, though, that general research on superstitions mentions little directly related to sports; so, by necessity, recourse is made to sports stories and newspaper and magazine articles. The main body of this paper presents results…

  7. Sports injuries and society.

    PubMed Central

    Davies, J. E.

    1981-01-01

    Injuries are classified and examples of the ways in which they can arise are given. Treatment, rehabilitation and the value of exercise are considered. A review of the effects of increasing leisure time and sports have been given, the value of legislation, education, protective clothing and close supervision in preventing the occurrence of injuries in sport is discussed. Images p80-a PMID:7248691

  8. Psychological Dynamics of Sport.

    ERIC Educational Resources Information Center

    Gill, Diane L.

    This book provides a comprehensive review of the branch of sport and exercise science that focuses on the psychological aspects of human behavior. Part I presents a general orientation to the field, including an introduction and description of sport psychology and a discussion of the history and current status of the field. Individual differences…

  9. Hazards of alpine sport.

    PubMed

    Robinson, M

    1991-07-01

    Alpine sports in Australia include downhill skiing, cross country skiing, snowboarding, snowmobiling and tobogganing. Despite a popular impression that the sport is risky the injury rate is low and there has been a large decrease in injuries relative to increased participation in the past 20 years. Nevertheless, more young skiers are sustaining injuries, many of which could be avoided.

  10. 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…

  11. Parents and Youth Sports.

    ERIC Educational Resources Information Center

    Kanters, Michael

    2002-01-01

    Asserts that parents play a critical role in their children's sports and should not be excluded, despite negative press about some "pushy" parents. The paper recommends that youth administrators encourage positive parental involvement in youth sports by acknowledging the important role that each parent plays and empowering them to do the right…

  12. The Aesthetic in Sport.

    ERIC Educational Resources Information Center

    Best, David

    This paper examines the relationship between sport and the aesthetic. It traces the logical character of the concept of the aesthetic as it applies to sport. A salient characteristic of the concept of the aesthetic is revealed by examining the aesthetic in relation to works of art, and this is then applied to the consideration of sporting…

  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. 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).

  15. 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.

  16. Managing for Motivation: Herzberg's Motivation-Hygiene Theory and Its Application to 4-H Leadership. National Intern Report.

    ERIC Educational Resources Information Center

    Freeman, Walter J.

    A study examined the organizational factors contributing to the motivation of 4-H volunteer leaders. A modified form of Herzberg's Motivation-Hygiene Theory served as the research design of the study. A total of 149 4-H leaders were interviewed regarding thirteen job factors: recognition; personal growth; relationships with other 4-H leaders,…

  17. 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…

  18. Current Practices for Training Staff to Accommodate Youth with Special Health Care Needs in the 4-H Camp Setting

    ERIC Educational Resources Information Center

    Mouton, Lauren; Bruce, Jacklyn

    2013-01-01

    The theory of inclusion is the foundation for the study reported here; inclusion is a focus not only of formal education, but also of nonformal educational settings such as 4-H. Ideally, 4-H camps are designed to serve youth of all backgrounds and abilities. By accommodating youth with special health care needs, 4-H camps are effectively meeting…

  19. E-Learning for 4-H Volunteers: Who Uses It, and What Can We Learn from Them?

    ERIC Educational Resources Information Center

    Ouellette, Kristy L.; Lesmeister, Marilyn K.; Lobley, Jennifer; Gross, Kerry M.

    2014-01-01

    Orienting and training 4-H volunteers are critical to individuals and the organization. The two-part study reported here re-establishes the profile of the 4-H volunteer and evaluates both the format and content of e-Learning for 4-H Volunteers modules launched in 2006. Volunteers from seven states perceived that online modules made learning more…

  20. 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.

  1. 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. PMID:16845530

  2. Shoot Tip Meristem Cryopreservation of Hypericum Species.

    PubMed

    Bruňáková, Katarína; Čellárová, Eva

    2016-01-01

    Based on our long-standing experience with in vitro culture of Hypericum perforatum, a clonal multiplication system and vitrification-based cryopreservation protocols have been applied to several Hypericum species: H. humifusum L., H. annulatum Moris, H. tomentosum L., H. tetrapterum Fries, H. pulchrum L., and H. rumeliacum Boiss. The shoot tips were cryopreserved using a uniform procedure that includes pretreatment with abscisic acid (ABA), PVS3 cryoprotection, and direct immersion into the liquid nitrogen (LN). The freezing-tolerant Hypericum species were pre-exposed to the cold acclimation conditions performed by a 7-day exposure to 4 °C. The content of naphtodianthrones (hypericins) including hypericin, pseudohypericin, and their protoforms was quantified by HPLC. Ploidy of plants was determined by both flow cytometry of leaf tissue and chromosome counts of root tip meristematic cells. We have shown that the post-thaw recovery rate of the shoot tips, pretreated with 0.076 μM ABA for 7 days at room temperature, led to the post-cryogenic survival from 5 % in H. tomentosum to 21 % in H. annulatum. As compared to the untreated (control) plants, the content of hypericins in plants regenerated after cryopreservation remained unchanged or decreased in H. perforatum, H. humifusum, H. annulatum, H. tomentosum, H. tetrapterum, and H. rumeliacum. However, the pre-exposition of the freezing-tolerant H. perforatum to cold acclimation prior to excision of the shoot tips has improved the post-thaw recovery to 45 % and resulted in threefold increase of the total hypericin content. PMID:27108308

  3. 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.

  4. Middle School Dropout? Enrollment Trends in the California 4-H Youth Development Program

    ERIC Educational Resources Information Center

    Russell, Stephen T.; Heck, Katherine E.

    2008-01-01

    There is a widespread belief that youth drop out of youth development programs during the middle school years. Alternative explanations for the smaller number of adolescent program participants have yet to be explored. We examine age trends in program enrollment using data from over 221,000 youth enrolled in the California 4-H Youth Development…

  5. 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…

  6. 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.

  7. 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…

  8. 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.

  9. 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…

  10. 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.

  11. Determining Directions for Change in a County 4-H Youth Program: The Role of Evaluation.

    ERIC Educational Resources Information Center

    Braverman, Marc; And Others

    This paper describes the evaluation of the 4-H youth program (serving ages 9 through 19) in Yolo County, California. The paper concentrates on the first component of the evaluation plan, a telephone survey of community needs and perceptions regarding services for youth which was conducted in November, 1984. The originally perceived questions…

  12. 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…

  13. 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…

  14. 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.

  15. 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…

  16. 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,…

  17. 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…

  18. Stakeholder Satisfaction with a 4-H Extension Program for Five- to Eight-Year-Old Children.

    ERIC Educational Resources Information Center

    Scheer, Scott D.; Lafontaine, Kenneth R.

    1999-01-01

    A 4-H K-2 program was evaluated by 277 parents, 144 volunteers, and 44 extension agents. These stakeholders believed the program was beneficial and effective in improving children's life skills (self-esteem, making friends, making choices, learning and physical skills). (SK)

  19. 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…

  20. 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,…

  1. 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…

  2. 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…

  3. County Clustering for the California 4-H Youth Development Program: Impacts and Lessons Learned

    ERIC Educational Resources Information Center

    Subramaniam, Aarti; Dasher, Harry Steve; Young, Jane Chin

    2012-01-01

    In response to budgetary constraints, a new staffing structure, the Pilot Leadership Plan, was proposed for California's 4-H Youth Development Program. County clusters were formed, each led by a coordinator. The plan was piloted for 2 years to provide insight into how county clustering could support Extension staff to increase and enhance…

  4. 4H-SiC photodiode model for DC SPICE circuit simulation

    NASA Astrophysics Data System (ADS)

    Kociubiński, Andrzej; Duk, Mariusz; Korona, Mateusz; Muzyka, Krzysztof

    2015-09-01

    Technology, characterization and in particularly modeling of 4H-SiC photodiode have been presented in this paper. Modeling and simulation has been performed using PSPICE environment. Comparison of simulation with real results for electrical characteristic (I-V) of circular SiC photodiodes has been also presented.

  5. 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

  6. Endocrine Aspects of 4H Leukodystrophy: A Case Report and Review of the Literature

    PubMed Central

    Billington, Emma; Bernard, Geneviève; Gibson, William; Corenblum, Bernard

    2015-01-01

    Introduction. 4H leukodystrophy is an autosomal recessive RNA polymerase III-related leukodystrophy, characterized by hypomyelination, with or without hypodontia (or other dental abnormalities) and hypogonadotropic hypogonadism. Case Presentation. We describe a 28-year-old female who presented with primary amenorrhea at the age of 19. She had a history of very mild neurological and dental abnormalities. She was found to have hypogonadotropic hypogonadism, and magnetic resonance imaging of the brain showed hypomyelination. The diagnosis of 4H leukodystrophy was made. She was subsequently found to have mutations in the POLR3B gene, which encodes the second largest subunit of RNA polymerase III. She wished to become pregnant and failed to respond to pulsatile GnRH but achieved normal follicular growth and ovulation with subcutaneous gonadotropin therapy. Discussion. Patients with 4H leukodystrophy may initially present with hypogonadotropic hypogonadism, particularly if neurological and dental manifestations are subtle. Making the diagnosis has important implications for prognosis and management. Progressive neurologic deterioration is expected, and progressive endocrine dysfunction may occur. Patients with 4H leukodystrophy should be counseled about disease progression and about this disease's autosomal recessive inheritance pattern. In those who wish to conceive, ovulation induction may be achieved with subcutaneous gonadotropin therapy, but pulsatile GnRH does not appear to be effective. PMID:26113998

  7. 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…

  8. 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…

  9. High-throughput phenotyping of plant shoots.

    PubMed

    Berger, Bettina; de Regt, Bas; Tester, Mark

    2012-01-01

    Advances in automated plant handling and image acquisition now make it possible to use digital imaging for the high-throughput phenotyping of plants. Various traits can be extracted from individual images. However, the potential of this technology lies in the acquisition of time series. Since whole shoot imaging is nondestructive, plants can now be monitored throughout their lifecycle, and dynamic traits such as plant growth and development can be captured and quantified. The technique is applicable to a wide range of plants and research areas and makes high-throughput screens possible, reducing the time and labor needed for the phenotypic characterization of plants.

  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. PMID:23245642

  11. 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.

  12. [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

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    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+N junction is used to collect high-energy electrons. The electron source is a titanium tritide (TiH3x) 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/cm2. Samples measured with an external tritium foil produced an open circuit voltage of 2.09 V, short circuit current of 75.47 nA/cm2, 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 105-106 cm/s. Our analysis demonstrated that the surface recombination dominates the performance of a tritium betavoltaic device but that using a thin P+N junction structure can mitigate some of the negative effects.

  14. 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.

  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. 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.

  17. [Sport for pacemaker patients].

    PubMed

    Israel, C W

    2012-06-01

    Sport activity is an important issue in many patients with a pacemaker either because they performed sport activities before pacemaker implantation to reduce the cardiovascular risk or to improve the course of an underlying cardiovascular disease (e.g. coronary artery disease, heart failure) by sports. Compared to patients with an implantable cardioverter defibrillator (ICD) the risks from underlying cardiovascular disease (e.g. ischemia, heart failure), arrhythmia, lead dysfunction or inappropriate therapy are less important or absent. Sport is contraindicated in dyspnea at rest, acute heart failure, new complex arrhythmia, acute myocarditis and acute myocardial infarction, valvular disease with indications for intervention and surgery and comorbidities which prevent physical activity. Patients with underlying cardiovascular disease (including hypertension) should preferably perform types and levels of physical activity that are aerobic (with dynamic exercise) such as running, swimming, cycling instead of sport with high anaerobic demands and high muscular workload. In heart failure, studies demonstrated advantages of isometric sport that increases the amount of muscle, thereby preventing cardiac cachexia. Sport with a risk of blows to the chest or physical contact (e.g. boxing, rugby, martial arts) should be avoided. Implantation, programming and follow-up should respect specific precautions to allow optimal physical activity with a pacemaker including implantation of bipolar leads on the side contralateral to the dominant hand, individual programming of the upper sensor and tracking rate and regular exercise testing. PMID:22854824

  18. 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. PMID:22830450

  19. 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.

  20. 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.

  1. 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…

  2. Opposite metabolic responses of shoots and roots to drought

    NASA Astrophysics Data System (ADS)

    Gargallo-Garriga, Albert; Sardans, Jordi; Pérez-Trujillo, Míriam; Rivas-Ubach, Albert; Oravec, Michal; Vecerova, Kristyna; Urban, Otmar; Jentsch, Anke; Kreyling, Juergen; Beierkuhnlein, Carl; Parella, Teodor; Peñuelas, Josep

    2014-10-01

    Shoots and roots are autotrophic and heterotrophic organs of plants with different physiological functions. Do they have different metabolomes? Do their metabolisms respond differently to environmental changes such as drought? We used metabolomics and elemental analyses to answer these questions. First, we show that shoots and roots have different metabolomes and nutrient and elemental stoichiometries. Second, we show that the shoot metabolome is much more variable among species and seasons than is the root metabolome. Third, we show that the metabolic response of shoots to drought contrasts with that of roots; shoots decrease their growth metabolism (lower concentrations of sugars, amino acids, nucleosides, N, P, and K), and roots increase it in a mirrored response. Shoots are metabolically deactivated during drought to reduce the consumption of water and nutrients, whereas roots are metabolically activated to enhance the uptake of water and nutrients, together buffering the effects of drought, at least at the short term.

  3. 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.

  4. 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

  5. Dietary supplements in sport.

    PubMed

    Burke, L M; Read, R S

    1993-01-01

    Studies of the dietary practices of athletes report that nutritional supplements are commonly used. Supplementation practices vary between sports and individual athletes; however, there is evidence that at least some athletes use a large number of supplements concurrently, often in doses that are very high in comparison with normal dietary intakes. In exploring supplementation practices we propose a classification system separating the supplements into dietary supplements and nutritional erogogenic aids. The dietary supplement is characterised as a product which can be used to address physiological or nutritional issues arising in sport. It may provide a convenient or practical means of consuming special nutrient requirements for exercise, or it may be used to prevent/reverse nutritional deficiencies that commonly occur among athletes. The basis of the dietary supplement is an understanding of nutritional requirements and physiological effects of exercise. When the supplement is used to successfully meet a physiological/nutritional goal arising in sport it may be demonstrated to improve sports performance. While there is some interest in refining the composition or formulation of some dietary supplements, the real interest belongs to the use or application of the supplement; i.e. educating athletes to understand and achieve their nutritional needs in a specific sports situation. The sports drink (carbohydrate-electrolyte replacement drink) is a well known example of a dietary supplement. Scientific attitudes towards the sports drink have changed over the past 20 years. Initial caution that carbohydrate-electrolyte fluids compromise gastric emptying during exercise has now been shown to be unjustified. Numerous studies have shown that 5 to 10% solutions of glucose, glucose polymers (maltodextrins) and other simple sugars all have suitable gastric emptying characteristics for the delivery of fluid and moderate amounts of carbohydrate substrate. The optimal

  6. Bone imaging in sports medicine.

    PubMed

    Shikare, S; Samsi, A B; Tilve, G H

    1997-01-01

    Increased participation in sports by the general public leads to increase in sports induced injuries including stress fractures, shin splints, arthritis and host of musculotendenous maladies. We have studied twenty patients referred from sports clinic for bone scanning to evaluate clinically difficult problems. It showed stress fracture in twelve patients, bilateral shin splint in five patients and normal bone scan in three patients. Present study highlights the utility of bone imaging for the diagnosis of various sports injuries in sports medicine.

  7. Micropropagation of Dendrobium nobile from shoot tip sections.

    PubMed

    Malabadi, Ravindra B; Mulgund, Gangadhar S; Kallappa, Nataraja

    2005-04-01

    Successful shoot regeneration of Dendrobium nobile was achieved using thin shoot tip sections and triacontanol (TRIA) for the first time. Protocorm-like bodies (PLBs) or proliferating shoot buds were observed when thin shoot tip sections were cultured on the basal medium of Mitra et at. (Indian J. Exp. Biol. 14 (1976) 350) supplemented with 4.0 microg L(-1) TRIA. The highest percentage of explants (93%) produced PLBs or proliferating shoot buds (21) at 4.0 microg L(-1) TRIA-supplemented basal medium. All the newly formed PLBs or proliferating shoot buds survived and ultimately produced healthy shoots with 2-3 leaves. Shoots produced roots when cultured on basal medium supplemented with 2.0 microg L(-1) TRIA. The well-rooted shoots were transferred to pots containing charcoal chips, coconut husk and broken tiles (2:2:1), and a 92% survival rate was achieved. This work reveals that TRIA can be used as an effective growth regulator in the micropropagation and conservation of D. nobile.

  8. Catastrophic pediatric sports injuries.

    PubMed

    Luckstead, Eugene F; Patel, Dilip R

    2002-06-01

    The high school sports of wrestling, gymnastics, ice hockey, baseball, track, and cheerleading should receive closer attention to prevent injury. Safer equipment and sport-specific conditioning should be provided and injuries strictly monitored. Greater attention must also be paid to swimming and diving techniques, and continued observation is needed for heat stroke and heat intolerance in sports such as football, wrestling, basketball, track and field, and cross-country. An increased awareness of commotio cordis in sports other than baseball should include ice hockey, football, track field events, and lacrosse. American football because of the sheer numbers and associated catastrophic injury potential must continue to be monitored at the highest medical levels! PMID:12119866

  9. 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.

  10. Preventing Children's Sports Injuries

    MedlinePlus

    ... ups and training sessions before practices and before games. This will help ensure that they have fun ... be allowed periods of rest during practices and games. previous continue Common Types of Sports Injuries Three ...

  11. Youth Sports Safety Statistics

    MedlinePlus

    ... the rate of concussions in boys, and in basketball the rate of concussions among girls was 293 ... students age 8-19 participating in sports like basketball, soccer and football between 1997 and 2007, even ...

  12. Sports Hernia (Athletic Pubalgia)

    MedlinePlus

    ... the pubic bone (adductors) are also stretched or torn. Cause Sports activities that involve planting the feet ... may need to consider surgery to repair the torn tissues. Page ( 2 ) AAOS does not endorse any ...

  13. The shoulder in sports.

    PubMed

    Cofield, R H; Simonet, W T

    1984-03-01

    Many sports activities that involve the upper extremity entail similar patterns of movement. Analysis of these activities, a better understanding of the throwing motion, and an awareness of shoulder diseases or injuries have led to a rational plan for investigation and management of shoulder problems. Evaluation often extends beyond the usual medical boundaries and must be based on information obtained from an analysis of sports mechanics, a review of training methods, and a physical examination directed at determination of flexibility, strength, endurance, and the presence of inflammation. Three common sports injuries are damage to the acromioclavicular joint (shoulder separation), instability of the glenohumeral joint, and a spectrum of pathologic changes in the rotator cuff. Sports that are commonly associated with shoulder problems include swimming, baseball, tennis, football, and gymnastics. Treatment may comprise rest, changes in training methods, an alteration of technique, and a physical rehabilitation program. Surgical treatment has a well-defined role, but it is usually optional.

  14. 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)

  15. Eye Injuries in Sports

    MedlinePlus

    ... these injuries can be prevented. Overall, basketball and baseball cause the most eye injuries, followed by water ... involve body contact. Some high-risk sports are baseball, basketball, hockey, football, lacrosse, tennis and other racquet ...

  16. 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.

  17. Detection of minority carrier traps in p-type 4H-SiC

    SciTech Connect

    Alfieri, G.; Kimoto, T.

    2014-03-03

    Contrarily to the case of n-type 4H-SiC, very little is known about the presence of minority carrier traps in p-type epilayers. In this study, we performed the electrical characterization of as-grown, electron irradiated, and thermally oxidized p-type 4H-SiC, by using minority carrier transient spectroscopy. Four minority carrier traps are reported in 1.6–2.3 eV energy range above the valence band edge (E{sub V}). Particular emphasis is given to the mid-gap minority carrier trap (EH{sub 6∕7}) and to its correlation to an energetically close mid-gap majority carrier trap (HK4)

  18. Magnesium chloride tetrahydrate, MgCl2·4H2O.

    PubMed

    Schmidt, Horst; Hennings, Erik; Voigt, Wolfgang

    2012-01-01

    The title compound, MgCl(2)·4H(2)O, was crystallized at 403 K and its structure determined at 200 K. The structure is built up from MgCl(2)(H(2)O)(4) octahedra with a trans configuration. Each complex is situated on a crystallographic twofold axis, with the rotation axis aligned along one H(2)O-Mg-OH(2) axis. They are connected by a complex network of O-H···Cl hydrogen bonds. The structure contains two-dimensional sections that are essentially identical to those in the reported tetrahydrates of CrCl(2), FeCl(2), FeBr(2) and CoBr(2), but they are stacked in a different manner in MgCl(2)·4H(2)O compared with the transition metal structures.

  19. 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.

  20. The C4H radical and the diffuse interstellar bands. An ab initio study

    NASA Technical Reports Server (NTRS)

    Kolbuszewski, Marcin

    1994-01-01

    An ab initio study of the low-lying electronic states of C4H has been presented where the species studied has a chi(2)sigma(+) ground state and two low lying pi states. Based on the vertical and adiabatic excitation energies between those states it is suggested that the 4428 A diffuse interstellar band is not carried by C4H. The application of the particle in a box model shows strong coincidences between the strong DIB's and predicted wavelengths of pi-pi transitions in C(2n)H series. Based on those coincidences, it is suggested the C(2n)H species as good candidates for carriers of diffuse interstellar bands.

  1. Donor-acceptor-pair emission in fluorescent 4H-SiC grown by PVT method

    SciTech Connect

    Liu, Xi Zhuo, Shi-Yi; Gao, Pan; Huang, Wei; Yan, Cheng-Feng; Shi, Er-Wei

    2015-04-15

    Fluorescent SiC, which contains donor and acceptor impurities with optimum concentrations, can work as a phosphor for visible light emission by donor-acceptor-pair (DAP) recombination. In this work, 3 inch N-B-Al co-doped fluorescent 4H-SiC crystals are prepared by PVT method. The p-type fluorescent 4H-SiC with low aluminum doping concentration can show intensive yellow-green fluorescence at room temperature. N-B DAP peak wavelength shifts from 578nm to 525nm and weak N-Al DAP emission occurred 403/420 nm quenches, when the temperature increases from 4K to 298K. The aluminum doping induces higher defect concentration in the fluorescent crystal and decreases optical transmissivity of the crystal in the visible light range. It triggers more non-radiative recombination and light absorption losses in the crystal.

  2. Characteristic morphologies of triangular defects on Si-face 4H-SiC epitaxial films

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    Triangular defects with a characteristic morphology consisting of a 3C-type structure were investigated on Si-face 4H-SiC epitaxial films using electron microscopy. Two types of triangular defects were investigated: one with a single valley on the surface along the [ 11 2 bar 0 ] direction and another with several parallel ridges and valleys called "washboard-like defects". The defects with a single valley had a characteristic domain structure consisting of four 3C crystals, which is similar to that of previously reported comet-shaped defects on the C-face. It is shown that the 3C domain in the washboard-like defect is covered by 4H layers with a washboard-like morphology.

  3. Electric-field dependence of electron drift velocity in 4H-SiC

    NASA Astrophysics Data System (ADS)

    Ivanov, P. A.; Potapov, A. S.; Samsonova, T. P.; Grekhov, I. V.

    2016-09-01

    Room temperature isothermal forward current-voltage characteristics of mesa-epitaxial 4H-SiC Schottky diodes were measured at high electric fields (beyond 105 V/cm) in the 34-μm thick n-base doped at 1 × 1015 cm-3. The effect of diode self-heating on current was minimized when using single 4-ns pulses. The analytical formula was derived for the dependence of electron drift velocity on electric field along c-axis.

  4. Enantioselective synthesis of 4H-pyranonaphthoquinones via sequential squaramide and silver catalysis.

    PubMed

    Kaya, Uğur; Chauhan, Pankaj; Hack, Daniel; Deckers, Kristina; Puttreddy, Rakesh; Rissanen, Kari; Enders, Dieter

    2016-01-28

    An enantioselective one-pot Michael addition/hydroalkoxylation reaction between 2-hydroxy-1,4-naphthoquinones and alkyne-tethered nitroalkenes catalyzed by a cinchona-derived squaramide and a silver(I) salt has been developed. The sequential protocol provides a direct access to 4H-pyranonaphthoquinones in moderate to very good yields and good to excellent enantioselectivities at a very low catalyst loading (0.5 mol%) of the squaramide.

  5. 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.

  6. Polarographic study of cadmium 5-hydroxy 2-(hydroxymethyl) 4H-pyran-4-one complex

    NASA Technical Reports Server (NTRS)

    Wilson, Ray F.; Daniels, Robert C.

    1989-01-01

    A polarographic study was performed on the products formed in the interaction of cadmium (II) with a 5-hydroxy 2-(hydroxymethyl) 4H-Pyran-4-one, using varying conditions of pH, supporting electrolytes, and concentrations. Measurements using the differential pulse method show that cadmium (II) exhibits a molar combining ratio of complexing agents to cation ranging from 1 to 1 to 3 to 1 depending on the pH and the supporting electrolyte employed.

  7. Enantioselective synthesis of 4H-pyranonaphthoquinones via sequential squaramide and silver catalysis.

    PubMed

    Kaya, Uğur; Chauhan, Pankaj; Hack, Daniel; Deckers, Kristina; Puttreddy, Rakesh; Rissanen, Kari; Enders, Dieter

    2016-01-28

    An enantioselective one-pot Michael addition/hydroalkoxylation reaction between 2-hydroxy-1,4-naphthoquinones and alkyne-tethered nitroalkenes catalyzed by a cinchona-derived squaramide and a silver(I) salt has been developed. The sequential protocol provides a direct access to 4H-pyranonaphthoquinones in moderate to very good yields and good to excellent enantioselectivities at a very low catalyst loading (0.5 mol%) of the squaramide. PMID:26660230

  8. 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.

  9. Theoretical microwave spectral constants for C3H/+/ and C4H/+/

    NASA Technical Reports Server (NTRS)

    Wilson, S.; Green, S.

    1980-01-01

    A number of linear conjugated carbon chain molecules have been observed in the interstellar gas. It has been suggested that ion molecule chemistry schemes may explain the formation of these compounds. In the present paper, theoretical bond lengths and rotation constants are obtained for C3H(+) and C4H(+). Calculations for C3 are used to assess the accuracy of the former. Recent results for C2H(+) are examined.

  10. 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.

  11. Carbon-antisite vacancy defect in 4H silicon carbide for realizing solid state qubit

    NASA Astrophysics Data System (ADS)

    Gali, Adam; Szász, Krisztián; Ivády, Viktor; Abrikosov, Igor; Bockstedte, Michel; Janzén, Erik

    2015-03-01

    Dopants in solids are promising candidates for implementations of quantum bits for quantum computing. Silicon carbide (SiC) with engineered point defects is considered as very promising material for the next generation devices, with applications ranging from electronics and photonics to quantum computing. Employing density functional theory and many body perturbation theory, we show that the neutral carbon antisite-vacancy pair (CAV) has high spin ground state, and that its spin may be coherently manipulated by optical excitation in n-type 4H SiC. As the positively charged CAV defect in 4H SiC has been recently engineered to act as single photon source, our finding brings a hope that optically addressed quantum bits can be realized by the neutral CAV defects in 4H SiC, and provide an additional target for researchers seeking for solid state single color centers for quantum information processes and metrology. The calculated zero-phonon line of the optically excited state is about 1550 nm (0.8 eV) which perfectly fits to the telecom wavelengths, that makes this qubit candidate very promising for integration of quantum optics devices with existing fiber optics technology. Lendület program of Hungarian Academy of Sciences, the Knut & Alice Wallenberg Foundation, Swedish Research Council, US DoE.

  12. 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).

  13. 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.

  14. 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.

  15. A remarkable activity of human leukotriene A4 hydrolase (LTA4H) toward unnatural amino acids.

    PubMed

    Byzia, Anna; Haeggström, Jesper Z; Salvesen, Guy S; Drag, Marcin

    2014-05-01

    Leukotriene A4 hydrolase (LTA4H--EC 3.3.2.6) is a bifunctional zinc metalloenzyme, which processes LTA4 through an epoxide hydrolase activity and is also able to trim one amino acid at a time from N-terminal peptidic substrates via its aminopeptidase activity. In this report, we have utilized a library of 130 individual proteinogenic and unnatural amino acid fluorogenic substrates to determine the aminopeptidase specificity of this enzyme. We have found that the best proteinogenic amino acid recognized by LTA4H is arginine. However, we have also observed several unnatural amino acids, which were significantly better in terms of cleavage rate (k cat/K m values). Among them, the benzyl ester of aspartic acid exhibited a k cat/K m value that was more than two orders of magnitude higher (1.75 × 10(5) M(-1) s(-1)) as compared to L-Arg (1.5 × 10(3) M(-1) s(-1)). This information can be used for design of potent inhibitors of this enzyme, but may also suggest yet undiscovered functions or specificities of LTA4H.

  16. Extended charge accumulation in ruthenium-4H-imidazole-based black absorbers: a theoretical design concept.

    PubMed

    Kupfer, Stephan

    2016-05-11

    A theoretical-guided design concept aiming to achieve highly efficient unidirectional charge transfer and multi-charge separation upon successive photoexcitation for light-harvesting dyes in the scope of supramolecular photocatalysts is presented. Four 4H-imidazole-ruthenium(ii) complexes incorporating a biimidazole-based electron-donating ligand sphere have been designed based on the well-known 4H-imidazole-ruthenium(ii) polypyridyl dyes. The quantum chemical evaluation, performed at the density functional and time-dependent density functional level of theory, revealed extraordinary unidirectional charge transfer bands from the near-infrared to the ultraviolet region of the absorption spectrum upon multi-photoexcitation. Spectro-electrochemical simulations modeling photoexcited intermediates determined the outstanding multi-electron storage capacity for this novel class of black dyes. These remarkable photochemical and photophysical properties are found to be preserved upon site-specific protonation rendering 4H-imidazole-ruthenium(ii) biimidazole dyes ideal for light-harvesting applications in the field of solar energy conversion. PMID:27121270

  17. Sports related to drowning.

    PubMed

    Szpilman, David; Orlowski, James P

    2016-09-01

    Aquatic sports are included in the top list of risky practices as the environment per se carries a possibility of death by drowning if not rescued in time. Not only are aquatic sports related to a high risk of death, but also all sports practiced on the water, over the water and on ice. Whatever the reason a person is in the water, drowning carries a higher possibility of death if the individual is unable to cope with the water situation, which may simply be caused by an inability to stay afloat and get out of the water or by an injury or disease that may lead to physical inability or unconsciousness. The competitive nature of sports is a common pathway that leads the sports person to exceed their ability to cope with the environment or simply misjudge their physical capability. Drowning involves some principles and medical interventions that are rarely found in other medical situations as it occurs in a deceptively hostile environment that may not seem dangerous. Therefore, it is essential that health professionals are aware of the complete sequence of action in drowning. This article focuses on the pulmonary injury in sports and recreational activities where drowning plays the major role. PMID:27581833

  18. 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.

  19. Interfacial atomic site characterization by photoelectron diffraction for 4H-AlN/4H-SiC(11\\bar{2}0) heterojunction

    NASA Astrophysics Data System (ADS)

    Maejima, Naoyuki; Horita, Masahiro; Matsui, Hirosuke; Matsushita, Tomohiro; Daimon, Hiroshi; Matsui, Fumihiko

    2016-08-01

    The interfacial atomic structure of an AlN thin film on a nonpolar 4H-SiC(11\\bar{2}0) substrate grown by atomic Al and N plasma deposition was studied by photoelectron diffraction and spectroscopy. The epitaxial growth of the thin film was confirmed by the comparison of element-specific photoelectron intensity angular distributions (PIADs). Depth profiles were analyzed by angle-resolved constant-final-state-mode X-ray photoelectron spectroscopy (AR-XPS). No polar angular dependence was observed in Al 2p spectra, while an additional intermixing component was found in interface-sensitive N 1s spectra. The site-specific N 1s PIADs for the AlN film and an intermixing component were derived from two N 1s PIADs with different binding energies. We attributed the intermixing component to SiN interfacial layer sites. In order to prevent SiN growth at the interface, we deposited Al on the SiC(11\\bar{2}0) substrate prior to the AlN growth. A significant reduction in the amount of intermixing components at the AlN/SiC interface was confirmed by AR-XPS.

  20. Hearing impairment in Thais due to sport shooting: a preliminary report.

    PubMed

    Charakorn, C; Amatyakul, P

    1998-05-01

    Ninety one sportshooters from several sportshooting clubs ranging in age from 20-49 and 85 control subjects were carefully examined for hearing ability. The male and female ratio was 10.37:1. It was found that 9.34 per cent of the subjects were suffering from hearing impairment at the level of 3,000-8,000 Hertz. At most frequencies the mean decibel between the groups of shooters (1-5 years, 5-10 years, more than 10 years) was significantly different, with the right ear being significantly more impaired than the left ear (alpha = 0.1). At all frequencies the mean decibel level for the control group was significantly different from that for the sportshooters (alpha = 0.1). In conclusion, it is the responsibility of the National Environmental Board on Noise Pollution, the Royal College of Otolaryngologists of Thailand and other related organizations should be much more aggressive in educating sportshooters with regard to protecting their ears against acoustic trauma. PMID:9623034

  1. 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)

  2. Incorporation of Tritiated Thymidine into Nuclei of Shoot Apical Meristems.

    PubMed

    Gifford, E M

    1960-02-01

    Tritiated thymidine enters readily into certain excised plant parts and into small aquatic plants. Attempts to introduce the radioisotope into shoot tips of seed plants via the roots have not proved satisfactory. The label readily enters the shoot if applied directly to immature leaves of a bud after the application of a wetting agent. PMID:17738067

  3. Role of endodermal cell vacuoles in shoot gravitropism.

    PubMed

    Kato, Takehide; Morita, Miyo Terao; Tasaka, Masao

    2002-06-01

    In higher plants, shoots and roots show negative and positive gravitropism, respectively. Data from surgical ablation experiments and analysis of starch deficient mutants have led to the suggestion that columella cells in the root cap function as gravity perception cells. On the other hand, endodermal cells are believed to be the statocytes (that is, gravity perceiving cells) of shoots. Statocytes in shoots and roots commonly contain amyloplasts which sediment under gravity. Through genetic research with Arabidopsis shoot gravitropism mutants, sgr1/scr and sgr7/shr, it was determined that endodermal cells are essential for shoot gravitropism. Moreover, some starch biosynthesis genes and EAL1 are important for the formation and maturation of amyloplasts in shoot endodermis. Thus, amyloplasts in the shoot endodermis would function as statoliths, just as in roots. The study of the sgr2 and zig/sgr4 mutants provides new insights into the early steps of shoot gravitropism, which still remains unclear. SGR2 and ZIG/SGR4 genes encode a phospholipase-like and a v-SNARE protein, respectively. Moreover, these genes are involved in vacuolar formation or function. Thus, the vacuole must play an important role in amyloplast sedimentation because the sgr2 and zig/sgr4 mutants display abnormal amyloplast sedimentation.

  4. 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.

  5. 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...

  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. Shoot production in squash (Cucurbita pepo) by in vitro organogenesis.

    PubMed

    Ananthakrishnan, G; Xia, X; Elman, C; Singer, S; Paris, H S; Gal-On, A; Gaba, V

    2003-04-01

    Seedling-derived cotyledon explants of squash ( Cucurbita pepo L.) of commercial cultivars True French, Ma'yan and Goldy were regenerated in vitro on Murashige and Skoog medium augmented with 1 mg/l benzyladenine. After 4 weeks in culture small shoots and buds regenerated only on the most proximal cotyledon edge. Culture on an elongation medium with a reduced cytokinin concentration (0.1 mg/l) with or without 1 mg/l gibberellic acid (GA(3)) facilitated the recovery of shoots. Fresh shoots could be recovered at each subculture of the regenerating mass. Peak productivity was during the third cycle of subculture, and shoot production ceased after the fifth subculture. Culture on elongation medium supplemented with GA(3) was 55% more effective with respect to overall shoot production than that on medium without GA(3), with 22 shoots recovered in total per explant from the former. Regeneration occurred under both light and dark conditions. All of the shoots tested were diploid. The shoots were rooted and transferred to the greenhouse where they grew and flowered normally.

  8. Sports medicine in New Zealand.

    PubMed Central

    Milne, C J

    1992-01-01

    Sports medicine in New Zealand is characterized by a team approach. Experienced professionals work together to the benefit of athletes, be they elite performers or those in sport for purely recreational purposes. A no-fault accident compensation scheme is used to provide speedy access to treatment services for those injured in sport and also for advice on accident prevention. Recent initiatives include a task force on drugs in sport and the creation of regional sports foundations. Sports medical education is a prominent part of the New Zealand scene. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:1600449

  9. 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

  10. 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. PMID:25496006

  11. 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

  12. 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.

  13. Epilepsy and sports participation.

    PubMed

    Howard, Gregory M; Radloff, Monika; Sevier, Thomas L

    2004-02-01

    Epilepsy is a common disease found in 2% of the population, affecting both young and old. Unfortunately, epileptics have previously been discouraged from participation in physical activity and sports for fear of inducing seizures or increasing seizure frequency. Despite a shift in medical recommendations toward encouraging rather than restricting participation, the stigma remains and epileptics continue to be less active than the general population. This results in increased body mass index, decreased aerobic endurance, poorer self-esteem, and higher levels of anxiety and depression. Although there are rare cases of exercise-induced seizures, studies have shown that physical activity can decrease seizure frequency, as well as lead to improved cardiovascular and psychologic health. The majority of sports are safe for epileptics to participate in with special attention to adequate seizure control, close monitoring of medications, and preparation of family, coaches, or trainers. Contact sports including football, hockey, and soccer have not been shown to induce seizures, and epileptics should not be precluded from participation. Water sports and swimming are felt to be safe if seizures are well controlled and direct supervision is present. Additional care must be taken in sports involving heights such as gymnastics, harnessed rock climbing, or horseback riding. Sports such as hang-gliding, scuba diving, or free climbing are not recommended, given the risk of severe injury or death, if a seizure were to occur during the activity. This article reviews the risks and benefits of physical activity in epileptics, discusses sports in which epileptics may participate, and addresses how to decrease possible risks for injury.

  14. What is a sports injury?

    PubMed

    Timpka, Toomas; Jacobsson, Jenny; Bickenbach, Jerome; Finch, Caroline F; Ekberg, Joakim; Nordenfelt, Lennart

    2014-04-01

    Current sports injury reporting systems lack a common conceptual basis. We propose a conceptual foundation as a basis for the recording of health problems associated with participation in sports, based on the notion of impairment used by the World Health Organization. We provide definitions of sports impairment concepts to represent the perspectives of health services, the participants in sports and physical exercise themselves, and sports institutions. For each perspective, the duration of the causative event is used as the norm for separating concepts into those denoting impairment conditions sustained instantly and those developing gradually over time. Regarding sports impairment sustained in isolated events, 'sports injury' denotes the loss of bodily function or structure that is the object of observations in clinical examinations; 'sports trauma' is defined as an immediate sensation of pain, discomfort or loss of functioning that is the object of athlete self-evaluations; and 'sports incapacity' is the sidelining of an athlete because of a health evaluation made by a legitimate sports authority that is the object of time loss observations. Correspondingly, sports impairment caused by excessive bouts of physical exercise is denoted as 'sports disease' (overuse syndrome) when observed by health service professionals during clinical examinations, 'sports illness' when observed by the athlete in self-evaluations, and 'sports sickness' when recorded as time loss from sports participation by a sports body representative. We propose a concerted development effort in this area that takes advantage of concurrent ontology management resources and involves the international sporting community in building terminology systems that have broad relevance. PMID:24469737

  15. 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

  16. Atomistic Simulations of Epitaxial Recrystallization in 4H-SiC along the [0001] Direction

    SciTech Connect

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

    2007-02-16

    Molecular dynamics (MD) methods have been employed to study the epitaxail recrystallization and amorphous-to-crystalline (a-c) transition in 4H-SiC, with simulation times of up to a few hundred ns and at temperatures of 1500 and 2000 K. Three nano-sized amorphous layers with the normal of a-c interfaces along the [-12-10 ], [-1010] and [0001] directions, respectively, were created within a crystalline cell to investigate the anisotropies of recrystallization processes. The recovery of bond defects at the interfaces is an important process driving the initial epitaxial recrystallization of the amorphous layers. The amorphous layers with the a-c interface normal along the [-12-10] direction can be completely recrystallized at the temperatures of 1500 and 2000 K, and along the [0001] direction at 2000 K. However, the recrystallized region is defected with dislocations and stacking faults. The temperatures required for complete recrystallization are in good agreement with those observed in experiments. On the other hand, the recrystallization processes for the a-c interface normal along [-1010] direction are hindered by the nucleation of polycrystalline phases. These secondary ordered phases have been identified as 4H- and 3C-SiC with different crystallographic orientations to the original 4H-SiC. The bond mismatches at the interfaces between different microcrystals result in the formation of a number of stacking faults. The temperature is an important parameter to control the nucleation of the secondary ordered phase, whereas the size of amorphous region has a significant effect on their growth. These results are in good agreement with the previous experimental observations.

  17. 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…

  18. 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…

  19. 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.

  20. 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

  1. Wrist injuries in sport.

    PubMed

    Howse, C

    1994-03-01

    The wrist is a complex joint that biomechanically transmits forces generated at the hand through to the forearm. The radial side of the wrist carries 80% of the axial load and the ulnar side the remaining 20% of the load. The incidence of wrist (and hand) injuries in the sporting population is approximately 25%. This tends to be higher in those sports using the hand and wrist, and when the potential for trauma is present. The injuries are divided into 4 categories: overuse, nerve (and vascular), traumatic, and weight-bearing injuries. Overuse injuries are common in sports involving the hand and wrist, such as racquet sports, netball, basketball and volleyball. Nerve injuries are more commonly compressive neuropathies, and are seen with cyclists who may compress the ulnar nerve in Guyon's canal. Vascular injuries are uncommon and usually result from a high velocity impact from balls. Traumatic injuries are the most common and are due to either a fall on to the wrist, a direct blow, or combination of a rotatory and torsional force. The weight-bearing injuries are more specific to gymnastics, and result from repetitive excessive compressive and rotational forces across the wrist. The pommel horse event is associated with a high incidence of wrist pain in male competitors. Arthroscopy of the wrist provides direct inspection of intra-articular structures and diagnosis of conditions that may be unclear with other investigations. As techniques advance, more conditions may be treated arthroscopically and potentially facilitate an earlier return to sport.

  2. High responsivity 4H-SiC based metal-semiconductor-metal ultraviolet photodetectors

    NASA Astrophysics Data System (ADS)

    Yang, Weifeng; Zhang, Feng; Liu, Zhuguang; Lü, Ying; Wu, Zhengyun

    2008-11-01

    4H-SiC based metal-semiconductor-metal (MSM) photodetectors with diverse spacing were designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current-voltage and spectral responsivity measurements were carried out at room temperature. The fabricated 4 μm-spacing device showed a very low dark current (0.25 pA at 5 V bias voltage), a typical responsivity of 0.103 A/W at 20 V, and a peak response wavelength at 290 nm. The fabricated devices held a high DUV to visible rejection ratio of >103.

  3. 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.

  4. Hydrogen Gas Sensors Fabricated on Atomically Flat 4H-SiC Webbed Cantilevers

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Spry, David J.; Trunek, Andrew J.; Evans, Laura J.; Chen, Liang-Yu; Hunter, Gary W.; Androjna, Drago

    2007-01-01

    This paper reports on initial results from the first device tested of a "second generation" Pt-SiC Schottky diode hydrogen gas sensor that: 1) resides on the top of atomically flat 4H-SiC webbed cantilevers, 2) has integrated heater resistor, and 3) is bonded and packaged. With proper selection of heater resistor and sensor diode biases, rapid detection of H2 down to concentrations of 20 ppm was achieved. A stable sensor current gain of 125 +/- 11 standard deviation was demonstrated during 250 hours of cyclic test exposures to 0.5% H2 and N2/air.

  5. 4H-SiC Schottky photodiodes for ultraviolet flame detection

    NASA Astrophysics Data System (ADS)

    Mazzillo, M.; Sciuto, A.

    2015-10-01

    In the last few years silicon carbide (SiC) has emerged as an appropriate material for the detection of very low ultraviolet photon fluxes even at elevated temperatures. In this paper we report on the electro-optical characteristics of large area interdigit Ni2Si/4H-SiC photodiodes in TO metal can package with a suitable molded cap quartz window with high transmission in the ultraviolet wavelength range. The detectors have been tested for the detection of the ultraviolet component of the yellow flame emitted by a small candle, showing good sensitivity for very weak photon fluxes notwithstanding the linear operation condition of the photodiodes.

  6. Dynamic characteristics of 4H-SiC drift step recovery diodes

    SciTech Connect

    Ivanov, P. A. Kon’kov, O. I.; Samsonova, T. P.; Potapov, A. S.; Grekhov, I. V.

    2015-11-15

    The dynamic characteristics of 4H-SiC p{sup +}–p–n{sub 0}–n{sup +} diodes are experimentally studied in the pulsed modes characteristic of the operation of drift step recovery diodes (DSRD-mode). The effect of the subnanosecond termination of the reverse current maintained by electron-hole plasma preliminarily pumped by a forward current pulse is analyzed in detail. The influence exerted on the DSRD effect by the amplitude of reverse-voltage pulses, the amplitude and duration of forward-current pulses, and the time delay between the forward and reverse pulses is demonstrated and accounted for.

  7. 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).

  8. 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.

  9. Development of 17 kV 4H-SiC PiN diode

    NASA Astrophysics Data System (ADS)

    Runhua, Huang; Yonghong, Tao; Ling, Wang; Gang, Chen; Song, Bai; Rui, Li; Yun, Li; Zhifei, Zhao

    2016-08-01

    The design, fabrication, and electrical characteristics of a 4H-SiC PiN diode with breakdown voltage higher than 17 kV are presented. The three-zone JTE has been used in the fabrication. Numerical simulations have been performed to optimize the parameters of the edge termination technique. The epilayer properties of the N-type are 175 μm with a doping of 2 × 1014 cm-3. With the three-zone JTE, a typical breakdown voltage of 17 kV has been achieved. Project supported by the National High Technology Research and Development Program of China (No. 2014AA041401).

  10. Development of 17 kV 4H-SiC PiN diode

    NASA Astrophysics Data System (ADS)

    Runhua, Huang; Yonghong, Tao; Ling, Wang; Gang, Chen; Song, Bai; Rui, Li; Yun, Li; Zhifei, Zhao

    2016-08-01

    The design, fabrication, and electrical characteristics of a 4H-SiC PiN diode with breakdown voltage higher than 17 kV are presented. The three-zone JTE has been used in the fabrication. Numerical simulations have been performed to optimize the parameters of the edge termination technique. The epilayer properties of the N-type are 175 μm with a doping of 2 × 1014 cm‑3. With the three-zone JTE, a typical breakdown voltage of 17 kV has been achieved. Project supported by the National High Technology Research and Development Program of China (No. 2014AA041401).

  11. 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)

  12. 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)

  13. 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.

  14. Catastrophic spine injuries in sports.

    PubMed

    Boden, Barry P; Prior, Chris

    2005-02-01

    Catastrophic spine injuries in sports are rare but tragic events. The sports with the highest risk of catastrophic spinal injuries are football, ice hockey, wrestling, diving, skiing and snowboarding, rugby, cheerleading, and baseball. A common mechanism of injury for all at-risk sports is an axial compression force to the top of the head with the neck slightly flexed. We review common mechanisms of injury and prevention strategies for spine injuries in the at-risk sports.

  15. [Liver and sport].

    PubMed

    Watelet, J

    2008-11-01

    The liver is a vital organ and plays a central role in energy exchange, protein synthesis as well as the elimination of waste products from the body. Acute and chronic injury may disturb a variety of liver functions to different degrees. Over the last three decades, the effects of physical activity and competitive sport on the liver have been described by various investigators. These include viral hepatitis and drug-induced liver disorders. Herein, we review acute and chronic liver diseases potentially caused by sport. Team physicians, trainers and others, responsible for the health of athletes, should be familiar with the risk factors, clinical features, and consequences of liver diseases that occur in sports.

  16. Complete genome sequence of the marine, cellulose and xylan degrading bacterium Glaciecola sp. 4H-3-7+YE-5

    SciTech Connect

    Klippel, Dr Barbara; Bruce, David; Davenport, Karen W.; Goodwin, Lynne A.; Han, James; Han, Shunsheng; Land, Miriam L; Mikhailova, Natalia; Nolan, Matt; Pennacchio, Len; Pitluck, Sam; Tapia, Roxanne; Woyke, Tanja; Wiebusch, Sigrid; Basner, Alexander; Abe, Fumiyoshi; Horikoshi, Koki; Antranikian, Garabed

    2011-01-01

    Glaciecola sp. 4H-3-7+YE-5 was isolated from deep sea sediments at Suruga Bay in Japan and is capable of efficiently hydrolyzing cellulose and xylan. The complete genome sequence of Glaciecola sp. 4H-3-7+YE-5 revealed several genes encoding putatively novel glycoside hydrolases associated with plant biomass degradation.

  17. A Mixed Method Study of Positional Leadership of North Dakota 4-H Ambassador and State FFA Officer Alumni

    ERIC Educational Resources Information Center

    Peterson, Nels Milan

    2010-01-01

    The purpose of this mixed method study was to determine the positional leadership of North Dakota 4-H and FFA leadership alumni. This study determined the influence of youth development programs on statewide leadership alumni (those who served from 1970 to 2000) and community leadership roles as adults. Former North Dakota 4-H Ambassador Alumni…

  18. 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…

  19. Eat, Grow, Lead 4-H: An Innovative Approach to Deliver Campus- Based Field Experiences to Pre-Entry Extension Educators

    ERIC Educational Resources Information Center

    Weeks, Penny Pennington; Weeks, William G.

    2012-01-01

    Eat, Grow, Lead 4-H Club was created as a pilot program for college students seeking to gain experience as non-formal youth educators, specifically serving pre-entry level Extension educators through a university-based 4-H club. Seventeen student volunteers contributed an estimated 630 hours of service to the club during spring 2011. The club…

  20. 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…

  1. 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…

  2. Sport Art: Spectacle or Sacrament.

    ERIC Educational Resources Information Center

    Studer, Ginny L., Ed.; And Others

    1982-01-01

    The chief objective of sport art is to capture that actual fleeting moment of excellent performance in a sporting event. In a series of articles, the significance of sport art is shown in its importance in recording historic contests and games, emphasizing social achievement and personal performance goals, and attempting to symbolize the depth of…

  3. The Sport-Stress Connection.

    ERIC Educational Resources Information Center

    Santomier, James

    1983-01-01

    This article explains how and why stress mechanisms operate in students who participate in sports. Students respond to different sport situations with various physical, psychological, and social reactions. When developing and supervising sports, school personnel should take into consideration the physical and psychological development of…

  4. 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…

  5. 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…

  6. 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)

  7. 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.

  8. Effect of Doping Concentration Variations in PVT-Grown 4H-SiC Wafers

    NASA Astrophysics Data System (ADS)

    Yang, Yu; Guo, Jianqiu; Goue, Ouloide; Raghothamachar, Balaji; Dudley, Michael; Chung, Gil; Sanchez, Edward; Quast, Jeff; Manning, Ian; Hansen, Darren

    2016-04-01

    Synchrotron white beam x-ray topography studies carried out on 4H-SiC wafers characterized by locally varying doping concentrations reveals the presence of overlapping Shockley stacking faults generated from residual surface scratches in regions of higher doping concentrations after the wafers have been subjected to heat treatment. The stacking faults are rhombus-shaped and bound by Shockley partial dislocations. The fault generation process is driven by the fact that in regions of higher doping concentrations, a faulted crystal containing double Shockley faults is more stable than a perfect 4H-SiC crystal at the high temperatures (>1000°C) that the wafers are subject to during heat treatment. We have developed a model for the formation mechanism of the rhombus-shaped stacking faults. Our studies show that during heat treatment of the wafer, such double Shockley faults can be generated in regions where dislocation sources are presents (e.g. scratches or low-angle boundaries) and when the nitrogen doping concentration exceeds a certain level.

  9. Evaluation of 4H-SiC Thermal Oxide Reliability Using Area-Scaling Method

    NASA Astrophysics Data System (ADS)

    Senzaki, Junji; Shimozato, Atsushi; Okamoto, Mitsuo; Kojima, Kazutoshi; Fukuda, Kenji; Okumura, Hajime; Arai, Kazuo

    2009-08-01

    The reliability of thermal oxides grown on an n-type 4H-SiC(0001) was investigated using an area-scaling method, and the influence of dislocation defects on the time-dependent dielectric breakdown characteristics of thermal oxides was examined. A thermal oxide was grown by dry oxidation at 1200 °C followed by nitrogen post-oxidation annealing. Using the area-scaling method, the time-to-breakdown (tBD) distribution curves of metal-oxide-semiconductor (MOS) capacitors with different gate area sizes were converged to a single one. It was clearly shown that origins of dielectric breakdown are edge breakdown and dislocation-related breakdown for steep and gradual slopes of the area-scaling normalized tBD distribution curve, respectively. In addition, a yield analysis of MOS capacitors quantitatively indicated that both threading screw dislocation and basal plane dislocation are predominant killer defects for the dielectric breakdown of thermal oxides on the 4H-SiC(0001) face.

  10. Characterization of V-shaped defects in 4H-SiC homoepitaxial layers

    DOE PAGES

    Zhang, Lihua; Su, Dong; Kisslinger, Kim; Stach, Eric; Chung, Gil; Zhang, Jie; Thomas, Bernd; Sanchez, Edward K; Mueller, Stephan G.; Hansen, Darren; et al

    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

  11. 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.

  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. 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.

  14. Comprehensive study of a 4H-SiC MES-MOSFET

    NASA Astrophysics Data System (ADS)

    Jamali Mahabadi, S. E.; Amini Moghadam, Hamid

    2015-11-01

    In this paper, we studied the enhancement of the breakdown voltage in the 4H-SiC MESFET-MOSFET (MES-MOSFET) structure which we have proposed in our previous work. We compared this structure with Conventional Bulk-MOSFET (CB-MOSFET) and Field plated Conventional Bulk-MOSFET (FCB-MOSFET) structures. The 4H-SiC MES-MOSFET structure consists of two additional schottky buried gates which behave like a Metal on Semiconductor (MES) at the interface of the active region and substrate. The motivation for this structure was to enhance the breakdown voltage by introducing a new technique of utilizing the reduced surface field (RESURF) concept. In our comparison and investigation we used a two-dimensional device simulator. Our simulation results show that the breakdown voltage of the proposed structure is 3.7 and 2.9 times larger than CB-MOSFET and FCB-MOSFET structures, respectively. We also showed that the threshold voltage and the slope of drain current (ID) as a function of drain-source voltage (VDS) for all the structures is the same.

  15. 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.

  16. 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.

  17. 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.

  18. Indoor racquet sports injuries.

    PubMed

    Silko, G J; Cullen, P T

    1994-08-01

    Family physicians can care for most patients injured while participating in indoor racquet sports. However, patients with injuries to the eye usually require ophthalmologic referral. The most common injuries that occur in persons participating in indoor racquet sports include contusions, sprains and strains, lacerations, eye injuries, bursitis and tendinitis. Musculoskeletal injuries that merit special consideration include lateral epicondylitis, DeQuervain's tenosynovitis, wrist intersection syndrome, patellar pain syndrome, meniscal injuries, Achilles tendinitis and plantar fasciitis. The family physician plays a critical role in providing patients with information about preventive measures.

  19. 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. PMID:27144474

  20. 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

  1. 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

  2. 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.

  3. Mutants in Arabidopsis thaliana with altered shoot gravitropism

    SciTech Connect

    Bullen, B.L.; Poff, K.L.

    1987-04-01

    A procedure has been developed and used to screen 40,000 m-2 seedlings of Arabidopsis thaliana for strains with altered shoot gravitropism. Several strains have been identified for which shoot gravitropism is considerably more random than that of their wild-type parent (based on frequency distribution histograms of the gravitropic response to a 1 g stimulus). One such strain exhibits normal hypocotyl phototropism and normal root gravitropism. Thus, the gravitropism pathway in the shoot contains at least one mutable element which is not required for root gravitropism.

  4. 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.

  5. More than Child's Play: Variable- And Pattern-Centered Approaches for Examining Effects of Sports Participation on Youth Development

    ERIC Educational Resources Information Center

    Zarrett, Nicole; Fay, Kristen; Li, Yibing; Carrano, Jennifer; Phelps, Erin; Lerner, Richard M.

    2009-01-01

    The authors used data from Grades 5 through 7 of the longitudinal 4-H Study of Positive Youth Development to assess relations among sports participation, other out-of-school-time (OST) activities, and indicators of youth development. They used a mixture of variable- and pattern-centered analyses aimed at disentangling different features of…

  6. 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.

  7. 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…

  8. 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…

  9. 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…

  10. 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,…

  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. Art and Sport.

    ERIC Educational Resources Information Center

    Best, David

    1980-01-01

    The author refutes arguments by S. K. Wertz, based on a definition by Ruth Shaw, that some sports may be classified as art forms. For Wertz's article, see "Journal of Aesthetic Education," v13, n1, p107-09, January, 1979. (SJL)

  13. 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)

  14. 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…

  15. Burnout in Youth Sports.

    ERIC Educational Resources Information Center

    Rotella, Robert J.; And Others

    1991-01-01

    Burnout is a condition of withdrawal from participation in sports as a result of stress. The most significant advance in the study of burnout has been a cognitive-affective model that contains situational, cognitive appraisal, physiological, and behavioral components. Suggestions for preventing and treating burnout are presented. (BC)

  16. 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 physical…

  17. Black Women in Sport.

    ERIC Educational Resources Information Center

    Green, Tina Sloan; And Others

    An overview of the achievements of black women in sports is presented in this collection of essays, biographical sketches, and philosophical investigations. The work is divided into five chapters, the first of which focuses on prejudice (racial and sexual), absence of black women as subjects in the research base, work/home/family pressures, black…

  18. "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…

  19. 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…

  20. 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 are: (1)…

  1. Defending College Sports.

    ERIC Educational Resources Information Center

    Blum, Debra E.

    1994-01-01

    A philosophy professor who supports college athletics battles to maintain credibility among his academic peers. His interest is in adding balance to criticism of college sports and calling attention to positive aspects such as teamwork and discipline. The professor also teaches a seminar in ethics for first-year athletes. (MSE)

  2. Sports Injuries in Children.

    ERIC Educational Resources Information Center

    Taft, Timothy N.

    1991-01-01

    A literature review revealed an absence of well-controlled studies concerning the prevention of sports injuries in children. A checklist outlines some causes of the overuse syndrome, including (1) training errors; (2) the nature of playing surfaces; (3) muscle imbalance; (4) anatomic malalignments; (5) construction of shoes; and (6) various…

  3. [Endurance sports and arythmias].

    PubMed

    Burgan, H; Burri, H

    2013-03-01

    Endurance sports can predispose to the occurrence of certain arrhythmias, making them more frequent in athletes than in the general population. Endurance athletes often exhibit electrocardiographic modifications that are difficult to interpret without specific knowledge of the athlete's ECG. Some of these ECG modifications and arrhythmias are benign, however others can be potentially life threatening.

  4. [Sports in ankylosing spondylitis].

    PubMed

    Spring, H

    1991-06-01

    As therapy of ankylosing spondylarthritis still remains empirical, gymnastics and sports are of particular importance within the treatment of this disease. They aim at the improvement or at least the preservation of mobility, force and endurance. By those means an eventual immobilisation of the axial skeleton or the peripheral joints should take place in a position as favourable to function as possible. Various joint mobilisation techniques as well as muscle stretching are used to improve mobility. The latter thus pointedly prevents muscular disbalances. Various training methods are able to improve muscular performance. Slow dynamic force training can be used in gymnastic lessons as well as in home programmes. Maximal and staying power can thus be increased. Aerobic muscular training favours general efficiency, has a positive influence on risk factors of cardiac and vascular diseases and improves thoracic excursion. Motivation of the patient is correlated with the diversion of exercise, therapies and sport activities. The suitability of these measures are to be judged by expected maximal strain, the control of motion pattern, the effect of external forces as well as by the hazard to fall. Each and every sport activity has to be accompanied by supportive gymnastics. The most important sport disciplines are evaluated.

  5. Competitive Anxiety in Sport.

    ERIC Educational Resources Information Center

    Martens, Rainer; And Others

    This book is a comprehensive review of competitive anxiety research that has used the Sport Competition Anxiety Test, or SCAT (a trait scale), and the Competitive State Anxiety Inventory-2 (CSAI-2). The book describes the theoretical basis and development procedures for both scales, including detailed information on reliability and validity. In…

  6. 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…

  7. Sports, Race, and Ressentiment.

    ERIC Educational Resources Information Center

    Dowling, William C.

    2000-01-01

    Discusses the problem of college sports corruption and the debate over "the plight of the black athlete," suggesting that this debate is actually not about race or athletics but a code for examining contradictions between education and mass democracy. Calls this the problem of "ressentiment." Examines how athletes have used the "plight of the…

  8. 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. PMID:9399327

  9. Plasma ignition and steady state simulations of the Linac4 H{sup −} ion source

    SciTech Connect

    Mattei, S. Lettry, J.; Grudiev, A.; Ohta, M.; Yasumoto, M.; Hatayama, A.

    2014-02-15

    The RF heating of the plasma in the Linac4 H{sup −} ion source has been simulated using a particle-in-cell Monte Carlo collision method. This model is applied to investigate the plasma formation starting from an initial low electron density of 10{sup 12} m{sup −3} and its stabilization at 10{sup 18} m{sup −3}. The plasma discharge at low electron density is driven by the capacitive coupling with the electric field generated by the antenna, and as the electron density increases the capacitive electric field is shielded by the plasma and induction drives the plasma heating process. Plasma properties such as e{sup −}/ion densities and energies, sheath formation, and shielding effect are presented and provide insight to the plasma properties of the hydrogen plasma.

  10. Evaluation of MOS structures processed on 4H SiC layers grown by PVT epitaxy

    NASA Astrophysics Data System (ADS)

    Ciechonski, R. R.; Syväjärvi, M.; Wahab, Q.; Yakimova, R.

    2005-12-01

    MOS capacitors have been fabricated on 4H-SiC epilayers grown by physical vapor transport (PVT) epitaxy. The properties were compared with those on similar structures based on chemical vapor deposition (CVD) layers. Capacitance-voltage ( C- V) and conductance measurements ( G- V) were performed in the frequency range of 1 kHz to 1 MHz and also at temperatures up to 475 K. Detailed investigations of the PVT structures indicate a stable behaviour of the interface traps from room temperature up to 475 K. The amount of positive oxide charge QO is 6.83 × 10 9 cm -2 at room temperature and decreases with temperature increase. This suggests that the processed devices are temperature stable. The density of interface states Dit obtained by Nicollian-Brews conductance method is lower in the structure based on the PVT grown sample.

  11. Band gap states of Ti, V, and Cr in 4H-silicon carbide

    NASA Astrophysics Data System (ADS)

    Achtziger, Norbert; Witthuhn, Wolfgang

    1997-07-01

    Band gap states of Ti, V, and Cr in n-type 4H-SiC were investigated by radiotracer deep level transient spectroscopy (DLTS). Doping with the radioactive isotopes 48V and 51Cr was done by recoil implantation followed by annealing (1600 K). Repeated DLTS measurements during the elemental transmutation of these isotopes to 48Ti and 51V, respectively, reveal the corresponding concentration changes of band gap states. Thus, six levels are identified in the band gap: Cr levels at 0.15, 0.18, and 0.74 eV, one V level at 0.97 eV, and two Ti levels at 0.13 and 0.17 eV below the conduction band edge.

  12. 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.

  13. Excess leakage currents in high-voltage 4H-SiC Schottky diodes

    SciTech Connect

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

    2010-05-15

    The high-voltage 4H-SiC Schottky diodes are fabricated with a nickel barrier and a guard system in the form of 'floating' planar p-n junctions. The analysis of I-V characteristics measured in a wide temperature range shows that the forward current is caused by thermionic emission; however, the current is 'excessive' in the reverse direction. It is assumed that the reverse current flows locally through the points of the penetrating-dislocation outcrop to the Ni-SiC interface. The shape of reverse I-V characteristics makes it possible to conclude that the electron transport is governed by the monopolar-injection mechanism (the space-charge limited current) with participation of capture traps.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Detection of powder formation in SiH4/H2 glow discharges

    NASA Astrophysics Data System (ADS)

    Alexiou, G.; Tsigaras, G.; Amanatides, E.; Mataras, D.

    2016-03-01

    Time-resolved self-bias voltage measurements and spatiotemporal resolved optical emission spectroscopy were used in order to monitor particle formation and instabilities in the initial stage of 13.56 MHz SiH4/H2. The effect of total gas pressure on the particles formation and the time required for the plasma to reach steady state was investigated. Both techniques were very sensitive in monitoring the nucleation and coagulation phase of particles formation. The characteristic times required for reaching steady state were similar for both techniques indicating that electrical properties and chemical kinetics are affected in a similar way from particle formation. The increase of pressure resulted in a significant shortening of the instability period and this can be a significant advantage in the deposition of device grade silicon thin films.

  19. Characterization of N-doped multilayer graphene grown on 4H-SiC (0001)

    NASA Astrophysics Data System (ADS)

    Arezki, Hakim; Ho, Kuan-I.; Jaffré, Alexandre; Alamarguy, David; Alvarez, José; Kleider, Jean-Paul; Lai, Chao-Sung; Boutchich, Mohamed

    2015-02-01

    Large-area graphene film doped with hetero-atoms is of great interest for a wide spectrum of nanoelectronics applications, such as field effect devices, super capacitors, fuel cells among many others. Here, we report the structural and electronic properties of nitrogen doped multilayer graphene on 4H-SiC (0001). The incorporation of nitrogen during the growth causes an increase in the D band on the Raman signature indicating that the nitrogen is creating defects. The analysis of micro-Raman mapping of G, D, 2D bands shows a predominantly trilayer graphene with a D band inherent to doping and inhomogeneous dopant distribution at the step edges. Ultraviolet photoelectron spectroscopy (UPS) indicates an n type work function (WF) of 4.1 eV. In addition, a top gate FET device was fabricated showing n-type I-V characteristic after the desorption of oxygen with high electron and holes mobilities.

  20. 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.

  1. Production of withaferin A in shoot cultures of Withania somnifera.

    PubMed

    Ray, S; Jha, S

    2001-07-01

    Multiple shoot cultures of Withania somnifera were established from single shoot tip explants and their potential for the production of two principle withanolides, withaferin A and withanolide D was investigated. Shoot tips grown on MS medium supplemented with BA (1 mg l(-1)) induced 10.0 +/- 1.15 microshoots per explants and shoot cultures accumulated both withanolides (withaferin A = 0.04%, withanolide D = 0.06%). Supplementation of MSSM (solid) agar medium with 4% sucrose enhanced accumulation of both withaferin A (0.16%) and withanolide D (0.08%). Reduction of the agar concentration to 0.16% increased the number of microshoots induced per explant to 25.5. MSSM liquid medium containing 10% coconut milk favoured a maximum increase in biomass (27 fold); number of microshoots induced (37.6 +/- 1.45) as well as accumulation of withaferin A (0.14%). PMID:11488457

  2. Set shot shooting performance and visual acuity in basketball.

    PubMed

    Applegate, R A; Applegate, R A

    1992-10-01

    Common sense suggests that decreasing visual acuity will have a negative effect on basketball shooting performance. To test the hypothesis that basketball shooting performance monotonically decreases with decreasing acuity, 19 subjects attempted 25 set shots from a fixed location at each of 5 different acuity levels: 6/6 or better and vision blurred (by optical defocus) to visual acuities of 6/12, 6/24, 6/48, and 6/75. Our results revealed a small but statistically nonsignificant decrease in shooting performance between the 6/6+ and 6/12 conditions. For visual acuities between 6/12 and 6/75, the number of baskets made remained constant. We conclude that decreases in visual acuity over the range of 6/6+ to 6/75 resulting from defocus do not significantly reduce set shot shooting performance.

  3. 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

  4. Genetic Mapping Reveals Broader Role of Vrn-H3 Gene in Root and Shoot Development beyond Heading in Barley.

    PubMed

    Arifuzzaman, Md; Günal, Süleyman; 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

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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. PMID:27119525

  10. Clinical spectrum of 4H leukodystrophy caused by POLR3A and POLR3B mutations

    PubMed Central

    Vanderver, Adeline; van Spaendonk, Rosalina M.L.; Schiffmann, Raphael; Brais, Bernard; Bugiani, Marianna; Sistermans, Erik; Catsman-Berrevoets, Coriene; Kros, Johan M.; Pinto, Pedro Soares; Pohl, Daniela; Tirupathi, Sandya; Strømme, Petter; de Grauw, Ton; Fribourg, Sébastien; Demos, Michelle; Pizzino, Amy; Naidu, Sakkubai; Guerrero, Kether; van der Knaap, Marjo S.; Bernard, Geneviève

    2014-01-01

    Objective: To study the clinical and radiologic spectrum and genotype–phenotype correlation of 4H (hypomyelination, hypodontia, hypogonadotropic hypogonadism) leukodystrophy caused by mutations in POLR3A or POLR3B. Methods: We performed a multinational cross-sectional observational study of the clinical, radiologic, and molecular characteristics of 105 mutation-proven cases. Results: The majority of patients presented before 6 years with gross motor delay or regression. Ten percent had an onset beyond 10 years. The disease course was milder in patients with POLR3B than in patients with POLR3A mutations. Other than the typical neurologic, dental, and endocrine features, myopia was seen in almost all and short stature in 50%. Dental and hormonal findings were not invariably present. Mutations in POLR3A and POLR3B were distributed throughout the genes. Except for French Canadian patients, patients from European backgrounds were more likely to have POLR3B mutations than other populations. Most patients carried the common c.1568T>A POLR3B mutation on one allele, homozygosity for which causes a mild phenotype. Systematic MRI review revealed that the combination of hypomyelination with relative T2 hypointensity of the ventrolateral thalamus, optic radiation, globus pallidus, and dentate nucleus, cerebellar atrophy, and thinning of the corpus callosum suggests the diagnosis. Conclusions: 4H is a well-recognizable clinical entity if all features are present. Mutations in POLR3A are associated with a more severe clinical course. MRI characteristics are helpful in addressing the diagnosis, especially if patients lack the cardinal non-neurologic features. PMID:25339210

  11. Development of 4H-pyridopyrimidines: a class of selective bacterial protein synthesis inhibitors

    PubMed Central

    2012-01-01

    Background We have identified a series of compounds that inhibit protein synthesis in bacteria. Initial IC50's in aminoacylation/translation (A/T) assays ranged from 3 to14 μM. This series of compounds are variations on a 5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-4-ol scaffold (e.g., 4H-pyridopyrimidine). Methods Greater than 80 analogs were prepared to investigate the structure-activity relationship (SAR). Structural modifications included changes in the central ring and substituent modifications in its periphery focusing on the 2- and 6-positions. An A/T system was used to determine IC50 values for activity of the analogs in biochemical assays. Minimum inhibitory concentrations (MIC) were determined for each analog against cultures of Enterococcus faecalis, Moraxella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli tolC mutants and E. coli modified with PMBN. Results Modifications to the 2-(pyridin-2-yl) ring resulted in complete inactivation of the compounds. However, certain modifications at the 6-position resulted in increased antimicrobial potency. The optimized compounds inhibited the growth of E. faecalis, M. catarrhalis, H. influenzae, S. pneumoniae, S. aureus, E. coli tolC, mutants and E. coli modified with PMBN with MIC values of 4, ≤ 0.12, 1, 2, 4, 1, 1 μg/ml, respectively. IC50 values in biochemical assay were reduced to mid-nanomolar range. Conclusion 4H-pyridopyrimidine analogs demonstrate broad-spectrum inhibition of bacterial growth and modification of the compounds establishes SAR. PMID:22373064

  12. 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.

  13. Synthesis of N-Aryl-3,5-dichloro-4H-1,2,6-thiadiazin-4-imines from 3,4,4,5-Tetrachloro-4H-1,2,6-thiadiazine.

    PubMed

    Kalogirou, Andreas S; Manoli, Maria; Koutentis, Panayiotis A

    2015-08-21

    Condensation of 3,4,4,5-tetrachloro-4H-1,2,6-thiadiazine with a range of anilines gave 22 N-aryl-3,5-dichloro-4H-1,2,6-thiadiazin-4-imines in 43-96% yields. The scope and limitations of this condensation are briefly investigated. Furthermore, mono- and bis-substitution of the C-3 and C-5 chlorines of 3,5-dichloro-N-phenyl-4H-1,2,6-thiadiazin-4-imine by amine and alkoxide nucleophiles is explored. Finally, Stille coupling chemistry is used to prepare several N-phenyl-3,5-diaryl-4H-1,2,6-thiadiazin-4-imines. PMID:26261875

  14. 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.

  15. Shoot regeneration from stem and leaf callus of Eucalyptus tereticornis.

    PubMed

    Subbaiah, M M; Minocha, S C

    1990-11-01

    Adventitious shoots were obtained from leaf and stem callus of Eucalyptus tereticornis SM. Callus was induced on B5 medium with 0.1 mg/l benzyladenine (BA) and 3 or 5 mg/l naphthalene acetic acid in the dark. Shoot initiation occurred on modified Woody Plant medium (mWP) containing 0.5 mg/l BA, 500 mg/l polyvinylpyrrolidone and 10% (v/v) coconut milk. Multiple shoots were also regenerated directly from hypocotyl segments of 4 to 6 week old seedlings on B5 medium with 0.5 mg/l BA. Regenerated shoots could be rooted with 100% efficiency on mWP medium containing 0.5 mg/l indolebutyric acid and transferred to soil in the greenhouse. Suspension cultures were obtained from the callus using B5 medium with 0.5 mg/l 2,4-dichlorophenoxyacetic acid. Callus clumps grew from less than 1 mm to 4-6 mm in diameter within two weeks on transfer to shoot regeneration medium but failed to form shoots or somatic embryos.

  16. 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.

  17. 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

  18. 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. PMID:23179712

  19. Changes in basketball shooting patterns as a function of distance.

    PubMed

    Liu, S; Burton, A W

    1999-12-01

    The effect of distance on the accuracy and movement form in basketball shooting was examined using a dynamic systems approach. Five male and five female young adults (M = 26 yr.) with no basketball experience beyond regular physical education shot a basketball 20 times at each of eight distances from 5 to 40 ft. (Natural condition). Also, they pretended to shoot the ball 5 times at each of the eight distances, for a total of 200 shots each (Pretend condition). In the Natural condition, shooting accuracy significantly decreased as shooting distance increased. Across both conditions and across four body components (feet position, hand position, trunk rotation, and jump height), the participants shifted from one movement pattern to another 86.3% of the time as shooting distance increased. The distances at which the transitions occurred were significantly shorter in the Natural than the Pretend condition for the feet and hand components but not the trunk and jump-height components. These results indicated that shooting a basketball at increasing distances can be portrayed as a dynamic system characterized by abrupt changes in at least four body components at critical distances.

  20. 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.

  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. More on Sports and the Big6.

    ERIC Educational Resources Information Center

    Eisenberg, Mike

    1998-01-01

    Presents strategies for relating the Big6 information problem-solving process to sports to gain students' attention, sustain it, and make instruction relevant to their interests. Lectures by coaches, computer-based sports games, sports information sources, the use of technology in sports, and judging sports events are discussed. (LRW)

  3. The effect of CH4/H2 ratio on the surface properties of HDPE treated by CHx ion beam bombardment

    NASA Astrophysics Data System (ADS)

    Ding, Wanyu; Guo, Yuanyuan; Ju, Dongying; Sato, Susumu; Tsunoda, Teruo

    2016-06-01

    The surface of high density polyethylene (HDPE) substrate was bombarded by the CHx group ion beam, which was generated by the mixture of CH4/H2. Varying the CH4/H2 ratio, HDPE surfaces with different chemical bond structures and properties were obtained. Raman and XPS results show that sp2 and sp3 bond structures are formed at HDPE surface bombarded by CHx group ions. The sp3 bond fraction at bombarded HDPE surface depends on the H2 ratio in CH4/H2 mixture, because the H ion/atom/molecule can improve the growth of sp3 bond structure. For HDPE surface bombarded by CH4/H2 = 50/50, sp3 bond fraction reaches the maximum of 30.5%, the surface roughness decreases to 17.04 nm, and the static contact angle of polar H2O molecule increased to 140.2∘.

  4. Water Status Related Root-to-Shoot Communication Regulates the Chilling Tolerance of Shoot in Cucumber (Cucumis sativus L.) Plants

    PubMed Central

    Zhang, Zi-Shan; Liu, Mei-Jun; Gao, Hui-Yuan; Jin, Li-Qiao; Li, Yu-Ting; Li, Qing-Ming; Ai, Xi-Zhen

    2015-01-01

    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. PMID:26471979

  5. 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.

  6. 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

    2015-01-01

    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. PMID:26471979

  7. Optical triggering of high-voltage (18 kV-class) 4H-SiC thyristors

    NASA Astrophysics Data System (ADS)

    Rumyantsev, S. L.; Levinshtein, M. E.; Shur, M. S.; Cheng, L.; Agarwal, A. K.; Palmour, J. W.

    2013-12-01

    Optical triggering of high-voltage (18 kV-class) 4H-SiC thyristors with a single amplification step (pilot thyristor) is reported. It is demonstrated that the switch-on processes in such high-voltage structures are quite different from the switch-on processes in 12 kV 4H-SiC thyristors. In particular, the switch-on process occurs in two stages even at maximum light pulse energy and rather high anode biases.

  8. Are HO radicals produced in the reaction of O(3P) with 1-C4H8 ?

    NASA Technical Reports Server (NTRS)

    Luria, M.; Simonaitis, R.; Heicklen, J.

    1972-01-01

    The reaction of O(3P) with 1-C4H8 was examined in the presence of CO which scavenges HO radicals to produce CO2. From the CO2 quantum yield, an upper limit to the efficiency of HO production in the reaction of O(3P) with 1-C4H8 was found to be 0.020 at both 298 and 473 K.

  9. Evolution of extended defects in PVT-grown 4H-silicon carbide single crystals

    NASA Astrophysics Data System (ADS)

    Lee, Jaewon

    The purpose of this thesis is to identify the origin and evolution of two types of extended defects frequently observed in physical vapor transport (PVT) grown hexagonal SiC bulk crystals. They are basal plane dislocations and threading edge dislocations. PVT-grown 4H-SiC single crystals were investigated using high-resolution x-ray diffraction, defect selective etching, and transmission electron microscopy. The (0008) diffraction peak position shifted about 2.5° along the 3 inch crystal diameter indicating the bending of the basal plane. Transmission electron microscopy revealed that the bending is due to deformation-induced basal plane dislocations with at least a partial edge character. The basal plane dislocations had a non-zero net Burgers vector with the net extra half plane pointing toward the seed side of the investigated crystals, and thus caused the basal plane to bend concave toward the growth direction. Approximately parallel basal plane dislocation arrays were shown to correspond to basal plane slip bands. The bending of entire boules and the global distribution of the slip bands indicated that the basal plane slip system was activated by the macroscopic shear stress resulting from the thermal gradient imposed on the crystal during the PVT growth. The fine structure of the 'star defect' in PVT-grown 4H-SiC single crystals was investigated using molten KOH etching, transmission x-ray topography, and transmission electron microscopy. The star defect is one of the macroscopic extended defects consisting of the defect center and symmetric dislocation arrays extending along six equivalent <11-20> directions. The <11-20> arms of the star defect were shown to consist of polygonized threading edge dislocation arrays, which correspond to prismatic slip bands. Transmission electron microscopy revealed that Burgers vectors of the dislocations are anti-parallel to corresponding arm directions, and the extra half planes of the dislocations extend toward the

  10. Enhancement of atmospheric H2SO4 / H2O nucleation: organic oxidation products versus amines

    NASA Astrophysics Data System (ADS)

    Berndt, T.; Sipilä, M.; Stratmann, F.; Petäjä, T.; Vanhanen, J.; Mikkilä, J.; Patokoski, J.; Taipale, R.; Mauldin, R. L., III; Kulmala, M.

    2014-01-01

    Atmospheric H2SO4 / H2O nucleation influencing effects have been studied in the flow tube IfT-LFT (Institute for Tropospheric Research - Laminar Flow Tube) at 293 ± 0.5 K and a pressure of 1 bar using synthetic air as the carrier gas. The presence of a possible background amine concentration in the order of 107-108 molecule cm-3 throughout the experiments has to be taken into account. In a first set of investigations, ozonolysis of olefins (tetramethylethylene, 1-methyl-cyclohexene, α-pinene and limonene) for close to atmospheric concentrations, served as the source of OH radicals and possibly other oxidants initiating H2SO4 formation starting from SO2. The oxidant generation is inevitably associated with the formation of organic oxidation products arising from the parent olefins. These products (first generation mainly) showed no clear effect on the number of nucleated particles within a wide range of experimental conditions for H2SO4 concentrations higher than ~107 molecule cm-3. Also the early growth process of the nucleated particles was not significantly influenced by the organic oxidation products in line with the expected growth by organic products using literature data. An additional, H2SO4-independent process of particle (nano-CN) formation was observed in the case of α-pinene and limonene ozonolysis for H2SO4 concentrations smaller than ~107 molecule cm-3. Furthermore, the findings confirm the appearance of an additional oxidant for SO2 beside OH radicals, very likely stabilized Criegee Intermediates (sCI). A second set of experiments has been performed in the presence of added amines in the concentrations range of a few 107-1010 molecule cm-3 applying photolytic OH radical generation for H2SO4 production without addition of other organics. All amines showed significant nucleation enhancement with increasing efficiency in the order pyridine < aniline < dimethylamine < trimethylamine. This result supports the idea of H2SO4 cluster stabilization by

  11. Contaminant exposures at the 4H shell mounds in the Santa Barbara Channel.

    PubMed

    Phillips, Charles R; Salazar, Michael H; Salazar, Sandra M; Snyder, Barry J

    2006-12-01

    Remobilization, bioavailability, and potential toxicity of chemical contaminants were evaluated at the 4H shell mounds - the site of abandoned offshore oil and gas production platforms in the Santa Barbara Channel region of the Southern California Bight. Evaluations used a weight-of-evidence approach based on results from bulk phase chemical analyses and laboratory toxicity testing of shell mound cores, in situ field bioassays using caged mussels, and surficial sediment chemistry. Shell mound cores contained elevated concentrations of metals associated with drilling wastes (e.g., Ba, Cr, Pb, and Zn), as well as monocyclic and polycyclic aromatic hydrocarbons (PAHs). The highest concentrations along with pockets of free oil were associated with the middle "cuttings" stratum. Sediments composited from all core strata caused significant acute toxicity and bioaccumulation of Ba and PAHs in test organisms during laboratory exposures. In contrast, caged mussels placed at each of the shell mounds for a period of 57-58 days had greater than 90% survival, and there were no significant differences in survival of mussels placed at the shell mounds and corresponding reference sites. While all mussel samples exhibited increases in shell length, whole animal weight, and tissue lipid content, in some cases growth metrics for the shell mound mussels were significantly higher than those for the reference sites. Concentrations of metals, PAHs, and polychlorinated biphenyls (PCBs) in tissues of the shell mound mussels were not significantly different from those at reference sites. The presence of labile aromatic hydrocarbons in shell mound cores and absence of significant contaminant accumulation of tissues of caged mussels indicated that chemical contaminants are not being remobilized from the 4H shell mounds. Surficial bottom sediments near the shell mounds contained elevated Ba concentrations that probably were associated with drilling wastes. However, concentrations did not

  12. Contaminant exposures at the 4H shell mounds in the Santa Barbara Channel.

    PubMed

    Phillips, Charles R; Salazar, Michael H; Salazar, Sandra M; Snyder, Barry J

    2006-12-01

    Remobilization, bioavailability, and potential toxicity of chemical contaminants were evaluated at the 4H shell mounds - the site of abandoned offshore oil and gas production platforms in the Santa Barbara Channel region of the Southern California Bight. Evaluations used a weight-of-evidence approach based on results from bulk phase chemical analyses and laboratory toxicity testing of shell mound cores, in situ field bioassays using caged mussels, and surficial sediment chemistry. Shell mound cores contained elevated concentrations of metals associated with drilling wastes (e.g., Ba, Cr, Pb, and Zn), as well as monocyclic and polycyclic aromatic hydrocarbons (PAHs). The highest concentrations along with pockets of free oil were associated with the middle "cuttings" stratum. Sediments composited from all core strata caused significant acute toxicity and bioaccumulation of Ba and PAHs in test organisms during laboratory exposures. In contrast, caged mussels placed at each of the shell mounds for a period of 57-58 days had greater than 90% survival, and there were no significant differences in survival of mussels placed at the shell mounds and corresponding reference sites. While all mussel samples exhibited increases in shell length, whole animal weight, and tissue lipid content, in some cases growth metrics for the shell mound mussels were significantly higher than those for the reference sites. Concentrations of metals, PAHs, and polychlorinated biphenyls (PCBs) in tissues of the shell mound mussels were not significantly different from those at reference sites. The presence of labile aromatic hydrocarbons in shell mound cores and absence of significant contaminant accumulation of tissues of caged mussels indicated that chemical contaminants are not being remobilized from the 4H shell mounds. Surficial bottom sediments near the shell mounds contained elevated Ba concentrations that probably were associated with drilling wastes. However, concentrations did not

  13. Root-Shoot Signaling crosstalk involved in the shoot growth promoting action of rhizospheric humic acids.

    PubMed

    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

    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

  14. 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

  15. Sport for tall.

    PubMed

    Khosla, T

    1983-09-10

    Eight new events (handball, basketball, and six rowing events) were introduced for women in the Olympic Games at Montreal in 1976. Of 187 women rowers who competed at Montreal, none was shorter than the mean height (162 cm, 64 in) of women aged 18-24 in the United States. In team events only two out of 250 participants were shorter than the reference mean. Even among the tall, it was the taller participants who won medals. What does the slogan "Sport for All" mean in this context? Moreover, the physical size required of champion rowers and basketball players is not to be found in some Asian, African, and Latin American populations. International contests in many such events therefore seem to be at variance with the first charter of the Olympic Games. An independent reviewing body is urgently needed to examine the merits of man made rules in many sporting contests. PMID:6412804

  16. 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.

  17. [Healthy children and sports].

    PubMed

    Backx, F J; Erich, W B

    1990-08-01

    Sport can be considered as an excellent alternative for unhealthy consumption habits and can compensate far the outcome of a sedentary lifestyle. The youngster can improve technique, coordination and flexibility in an easy way by training programs. Specific weight training programs are not recommended for those under the age of fifteen years. Regular exercise programs at young ages have positive effects on the general education, and during life habitual exercise training reduce the severity of cardiovascular and other diseases. It promotes the fitness of the body and the mind. Sport, a lifetime, must be part of a healthy lifestyle and must be encouraged younger ages. Health effects in a long term depend on exercise programs lasting years.

  18. [The pediatrician and sports].

    PubMed

    Theintz, G E

    1985-01-01

    In contrast to recreative sports, competition should not be allowed in children without regulations and supervision. Physical handicaps should be carefully looked for through a thorough pre-participation examination and appropriate physical activities should be defined for handicapped children. Hypoactivity, fear of accident and functional deterioration cause more damage to these children than physical training which may include competition provided the underlying disease is adequately treated. Regular physical exercise appears to provide significant physical and psychological benefits which are effective beyond the period of physical activity. Stress and aggressivity linked to competition do not seem to have harmful effects on child mental health, with an exception for elite adolescent athletes for whom more information is needed. These athletes are at risk for orthopaedic lesions by overuse as well as disturbances of cardiac and endocrine functions which may disqualify them temporarily for sport events. Treatments designed to boost performance such as anabolic steroids, amphetamines or blood transfusions should be strictly forbidden.

  19. Sport for tall.

    PubMed

    Khosla, T

    1983-09-10

    Eight new events (handball, basketball, and six rowing events) were introduced for women in the Olympic Games at Montreal in 1976. Of 187 women rowers who competed at Montreal, none was shorter than the mean height (162 cm, 64 in) of women aged 18-24 in the United States. In team events only two out of 250 participants were shorter than the reference mean. Even among the tall, it was the taller participants who won medals. What does the slogan "Sport for All" mean in this context? Moreover, the physical size required of champion rowers and basketball players is not to be found in some Asian, African, and Latin American populations. International contests in many such events therefore seem to be at variance with the first charter of the Olympic Games. An independent reviewing body is urgently needed to examine the merits of man made rules in many sporting contests.

  20. Water relations, gas exchange and growth of dominant and suppressed shoots of Arbutus unedo L.

    PubMed

    Castell, C; Terradas, J

    1995-06-01

    Basal shoots produced by Arbutus unedo L. after cutting at ground level vary in size and growth rate, and are classified accordingly as dominant or suppressed. The suppressed shoots eventually cease growth and die. In this study, we investigated the role of light and water in the competition among shoots of A. unedo. Dominant and suppressed shoots of A. unedo showed similar leaf water potentials and tissue water relations over the year, suggesting that water status is not responsible for the lack of flushing in suppressed shoots. Although suppressed shoots did not flush under low light, they showed many characteristics of shade-tolerant plants. Leaves of suppressed shoots had lower leaf conductance and light-saturated photosynthetic rate, and higher specific leaf area than leaves of dominant shoots. We conclude that light was the main resource determining competition among shoots and the death of suppressed shoots. PMID:14965950