Science.gov

Sample records for prize winner positron

  1. 1993 Gordon Bell Prize Winners

    NASA Technical Reports Server (NTRS)

    Karp, Alan H.; Simon, Horst; Heller, Don; Cooper, D. M. (Technical Monitor)

    1994-01-01

    The Gordon Bell Prize recognizes significant achievements in the application of supercomputers to scientific and engineering problems. In 1993, finalists were named for work in three categories: (1) Performance, which recognizes those who solved a real problem in the quickest elapsed time. (2) Price/performance, which encourages the development of cost-effective supercomputing. (3) Compiler-generated speedup, which measures how well compiler writers are facilitating the programming of parallel processors. The winners were announced November 17 at the Supercomputing 93 conference in Portland, Oregon. Gordon Bell, an independent consultant in Los Altos, California, is sponsoring $2,000 in prizes each year for 10 years to promote practical parallel processing research. This is the sixth year of the prize, which Computer administers. Something unprecedented in Gordon Bell Prize competition occurred this year: A computer manufacturer was singled out for recognition. Nine entries reporting results obtained on the Cray C90 were received, seven of the submissions orchestrated by Cray Research. Although none of these entries showed sufficiently high performance to win outright, the judges were impressed by the breadth of applications that ran well on this machine, all nine running at more than a third of the peak performance of the machine.

  2. Special issue: Culham Thesis Prize winners

    NASA Astrophysics Data System (ADS)

    Ham, C. J.

    2015-01-01

    The Culham Thesis Prize is awarded annually to the nominee who has displayed an excellence in the execution of the scientific method as witnessed by the award of Doctor of Philosophy in Plasma Science from a UK or Irish university. The thesis content should exhibit significant new work and originality, clearly driven by the nominee, be well explained and demonstrate a good understanding of the subject. The prize is awarded at the Institute of Physics Plasma Physics Group Spring Conference and the prize winner gives an invited talk about their thesis work. The prize is sponsored by Culham Centre for Fusion Energy.

  3. Nobel Prize Winners in Astronomy

    NASA Astrophysics Data System (ADS)

    Moore, P.; Murdin, P.

    2000-11-01

    One of the greatest honours which can be bestowed upon any human being is the Nobel Prize. It is named after Alfred Nobel, a Swedish physicist who was particularly noted for his work on explosives. Nobel was born in 1833, and had a long and successful career, so that, when he died, on 10 December 1896, he left a large sum of money. This was to be put into a trust to establish an annual prize to t...

  4. Grand Prize and Citation Winners: Ten School with Soaring Expectations.

    ERIC Educational Resources Information Center

    Learning By Design, 2002

    2002-01-01

    Describes the design features of the grand prize winners of the 2002 "Learning by Design" contest--an addition to West Linn High School in West Linn, Oregon, and the renovation of Beaver Brook Academic Center/The Ethel Walker School in Simsbury, Connecticut. Also describes the designs of the eight citation winners. (EV)

  5. [Women in natural sciences--Nobel Prize winners].

    PubMed

    Zuskin, Eugenija; Mustajbegović, Jadranka; Lipozencić, Jasna; Kolcić, Ivana; Spoljar-Vrzina, Sanja; Polasek, Ozren

    2006-01-01

    Alfred Bernhard Nobel was the founder of the Nobel Foundation, which has been awarding world-known scientists since 1901, for their contribution to the welfare of mankind. The life and accomplishments of Alfred Bernhard Nobel are described as well as scientific achivements of 11 women, Nobel prize winners in the field of physics, chemistry, physiology and/or medicine. They are Marie Sklodowska Curie, Maria Goeppert Mayer, Irene Joliot-Curie, Dorothy Crowfoot Hodgkin, Gerty Theresa Radnitz Cori, Rosalyn Sussman Yalow, Barbara McClintock, Rita Levi-Montalcini, Gertrude Elion, Christine Nusslein-Volhard and Linda B. Buck.

  6. Pat Thiel talks about Nobel Prize winner Dan Shechtman

    SciTech Connect

    Thiel, Pat

    2012-01-01

    Ames Laboratory senior scientist and Iowa State University Distinguished Professor of Chemistry Pat Thiel talks about her friend and colleague Dan Shechtman who received the 2011 Nobel Prize for Chemistry.

  7. Pat Thiel talks about Nobel Prize winner Dan Shechtman

    ScienceCinema

    Thiel, Pat

    2016-07-12

    Ames Laboratory senior scientist and Iowa State University Distinguished Professor of Chemistry Pat Thiel talks about her friend and colleague Dan Shechtman who received the 2011 Nobel Prize for Chemistry.

  8. PEOPLE IN PHYSICS: Nobel prize winners in physics from 1901 to 1990: simple statistics for physics teachers

    NASA Astrophysics Data System (ADS)

    Zhang, Weijia; Fuller, Robert G.

    1998-05-01

    A demographic database for the 139 Nobel prize winners in physics from 1901 to 1990 has been created from a variety of sources. The results of our statistical study are discussed in the light of the implications for physics teaching.

  9. Modular Curriculum: English, American Nobel Prize Winners in Literature.

    ERIC Educational Resources Information Center

    Phillips, James A.

    This independent study module treats those Americans who have been awarded the Nobel Prize in Literature. They include Sinclair Lewis, Eugene O'Neill, T. S. Eliot, William Faulkner, Ernest Hemingway, John Steinbeck, and Pearl Buck. Selections from the writings of these authors are included. Their works represent many literary genres and also…

  10. More than Prize Lists: Head Teachers, Student Prize Winners, School Ceremonies and Educational Promotion in Colonial South Australia

    ERIC Educational Resources Information Center

    Young, Marisa

    2007-01-01

    Australian educators now operate in environments that frequently stress marketing activities. This article highlights the ways that colonial school prize ceremonies were deliberately developed to promote teaching activities. These ceremonies were part of carefully considered strategies that helped to boost the status of entrepreneurial teachers…

  11. Following Zahka: Using Nobel Prize Winners' Speeches and Ideas to Teach Economics

    ERIC Educational Resources Information Center

    Shanahan, Martin P.; Wilson, John K.; Becker, William E.

    2012-01-01

    Over 20 years ago, the late William Zahka (1990, 1998) outlined how the acceptance speeches of those who received the Nobel Memorial Prize in Economic Science could be used to teach undergraduates. This article updates and expands Zahka's work, identifying some of the issues discussed by recent Nobel Laureates, classifying their speeches by topic…

  12. Nils Gustav Dalén, the Unknown Nobel Prize Winner

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2009-01-01

    Hanging on the wall of my museum is a large "Map of Physics" published by the Central Scientific Company in 1938. On it is a list of the Nobel Prizes in physics, starting with Roentgen in 1901 and ending with Fermi in 1938. I can recognize every name except the one for 1912: Nils Gustav Dalén. Perhaps you have had the same experience when looking through the updated list.

  13. Theodore William Richards: apostle of atomic weights and Nobel Prize winner in 1914.

    PubMed

    Herschbach, Dudley R

    2014-12-15

    In recognition of his exact determinations of the atomic weights of a large number of the chemical elements, T. W. Richards received the Nobel Prize in Chemistry in 1914. His meticulous techniques resulted in "a degree of accuracy never before attained". This Essay follows Richards from his precocious youth to becoming a celebrated chemist and emphasizes his dedication to forseeing likely sources of error and how to avoid them.

  14. Radiation risk and nuclear medicine: An interview with a Nobel Prize winner

    SciTech Connect

    Yalow, R.S.

    1995-12-01

    In a speech given years ago at the Veterans Administration Medical Center, Bronx, NY, Rosalyn S. Yalow, 1977 Nobel Prize recipient for her invention of radioimmunoassay, made several salient points on the perception of fear or hazards from exposure to low-level radiation and low-level radioactive wastes. For the past three years, Yalow has been concerned with the general fear of radiation. In this interview, Newsline solicited Yalow`s views on public perceptions on radiation risk and what the nuclear medicine community can do to emphasize the fact that, if properly managed, the use of isotopes in medicine and other cases is not dangerous.

  15. Selman A. Waksman, winner of the 1952 Nobel Prize for physiology or medicine.

    PubMed

    Woodruff, H Boyd

    2014-01-01

    The history of the discovery and development of streptomycin is reviewed here from the personal standpoint of a member of Dr. Selman Waksman's antibiotic screening research team. The team approach of eight individuals illustrates how the gradual enhancement of the screening methodology was developed. I illustrate three study periods with key aspects in the development of streptomycin which led to a Nobel Prize being granted to Professor Waksman. One item not previously emphasized is the employment of a submerged culture technique for large-scale production of streptomycin, thus enabling rapid animal testing and human clinical trials with Mycobacterium tuberculosis. Another is that purified streptomycin was shown by Dr. Waksman to be distinctly different from the substances called natural products, which are no longer patentable in the United States; therefore, streptomycin was found to be patentable. A third item not previously emphasized is his emphasis on the screening of actinomycetes, including the newly named Streptomyces genus. All of these factors contributed to the success of streptomycin in the treatment of tuberculosis. In combination, their successes led to Dr. Waksman's department becoming a new pharmacological research area, specializing in drug discovery. These unique accomplishments all burnish the prior rationales used by the Karolinska Institute in granting Dr. Waksman alone the 1952 Nobel Prize for Physiology or Medicine.

  16. [Ilya Ilich Metchnikov and Paul Ehrlich: 1908 Nobel Prize winners for their research on immunity].

    PubMed

    Lokaj, J; John, C

    2008-11-01

    The Nobel Prize in Physiology or Medicine in 1908 was awarded to Ilya I. Mechnikov and Paul Ehrlich for recognition of their work on immunity. Mechnikov have discovered phagocytes and phagocytosis as the basis of natural cellular immunity. His ,,phagocytic theory" is the principle of immunological concept "self and not self" as the prerequisition of physiological inflammation, and selfmaintaining of organism. Ehrlich developed the methods for standardization of antibody activity in immune sera, described neutralizing and complement-depending effect of antibodies and enunciated the ,"ide-chain" theory of the formation of antibodies. Their concept of the key-stone of immunity was different, but they expressed the basic paradigma of immunology: immunity imply the protection of identity and guarantee the integrity of organism. Both are the founders of immunology as the scientific discipline. Discoveries and conceptions of I. Mechnikov and P. Ehrlich exceedingly influenced development of immunology and are also applicable, instructive and suggestive in contemporary immunology and microbiology.

  17. Nobel prizes: contributions to cardiology.

    PubMed

    Mesquita, Evandro Tinoco; Marchese, Luana de Decco; Dias, Danielle Warol; Barbeito, Andressa Brasil; Gomes, Jonathan Costa; Muradas, Maria Clara Soares; Lanzieri, Pedro Gemal; Gismondi, Ronaldo Altenburg

    2015-08-01

    The Nobel Prize was created by Alfred Nobel. The first prize was awarded in 1901 and Emil Adolf von Behring was the first laureate in medicine due to his research in diphtheria serum. Regarding cardiology, Nobel Prize's history permits a global comprehension of progress in pathophysiology, diagnosis and therapeutics of various cardiac diseases in last 120 years. The objective of this study was to review the major scientific discoveries contemplated by Nobel Prizes that contributed to cardiology. In addition, we also hypothesized why Carlos Chagas, one of our most important scientists, did not win the prize in two occasions. We carried out a non-systematic review of Nobel Prize winners, selecting the main studies relevant to heart diseaseamong the laureates. In the period between 1901 and 2013, 204 researches and 104 prizes were awarded in Nobel Prize, of which 16 (15%) studies were important for cardiovascular area. There were 33 (16%) laureates, and two (6%) were women. Fourteen (42%) were American, 15 (45%) Europeans and four (13%) were from other countries. There was only one winner born in Brazil, Peter Medawar, whose career was all in England. Reviewing the history of the Nobel Prize in physiology or medicine area made possible to identify which researchers and studies had contributed to advances in the diagnosis, prevention and treatment of cardiovascular diseases. Most winners were North Americans and Europeans, and male.

  18. Nobel Prizes: Contributions to Cardiology

    PubMed Central

    Mesquita, Evandro Tinoco; Marchese, Luana de Decco; Dias, Danielle Warol; Barbeito, Andressa Brasil; Gomes, Jonathan Costa; Muradas, Maria Clara Soares; Lanzieri, Pedro Gemal; Gismondi, Ronaldo Altenburg

    2015-01-01

    The Nobel Prize was created by Alfred Nobel. The first prize was awarded in 1901 and Emil Adolf von Behring was the first laureate in medicine due to his research in diphtheria serum. Regarding cardiology, Nobel Prize’s history permits a global comprehension of progress in pathophysiology, diagnosis and therapeutics of various cardiac diseases in last 120 years. The objective of this study was to review the major scientific discoveries contemplated by Nobel Prizes that contributed to cardiology. In addition, we also hypothesized why Carlos Chagas, one of our most important scientists, did not win the prize in two occasions. We carried out a non-systematic review of Nobel Prize winners, selecting the main studies relevant to heart diseaseamong the laureates. In the period between 1901 and 2013, 204 researches and 104 prizes were awarded in Nobel Prize, of which 16 (15%) studies were important for cardiovascular area. There were 33 (16%) laureates, and two (6%) were women. Fourteen (42%) were American, 15 (45%) Europeans and four (13%) were from other countries. There was only one winner born in Brazil, Peter Medawar, whose career was all in England. Reviewing the history of the Nobel Prize in physiology or medicine area made possible to identify which researchers and studies had contributed to advances in the diagnosis, prevention and treatment of cardiovascular diseases. Most winners were North Americans and Europeans, and male. PMID:25945466

  19. Heroes in endocrinology: Nobel Prizes.

    PubMed

    de Herder, Wouter W

    2014-09-01

    The Nobel Prize in Physiology or Medicine was first awarded in 1901. Since then, the Nobel Prizes in Physiology or Medicine, Chemistry and Physics have been awarded to at least 33 distinguished researchers who were directly or indirectly involved in research into the field of endocrinology. This paper reflects on the life histories, careers and achievements of 11 of them: Frederick G Banting, Roger Guillemin, Philip S Hench, Bernardo A Houssay, Edward C Kendall, E Theodor Kocher, John J R Macleod, Tadeus Reichstein, Andrew V Schally, Earl W Sutherland, Jr and Rosalyn Yalow. All were eminent scientists, distinguished lecturers and winners of many prizes and awards.

  20. Heroes in endocrinology: Nobel Prizes

    PubMed Central

    de Herder, Wouter W

    2014-01-01

    The Nobel Prize in Physiology or Medicine was first awarded in 1901. Since then, the Nobel Prizes in Physiology or Medicine, Chemistry and Physics have been awarded to at least 33 distinguished researchers who were directly or indirectly involved in research into the field of endocrinology. This paper reflects on the life histories, careers and achievements of 11 of them: Frederick G Banting, Roger Guillemin, Philip S Hench, Bernardo A Houssay, Edward C Kendall, E Theodor Kocher, John J R Macleod, Tadeus Reichstein, Andrew V Schally, Earl W Sutherland, Jr and Rosalyn Yalow. All were eminent scientists, distinguished lecturers and winners of many prizes and awards. PMID:25055817

  1. Citations Prize 2010 Citations Prize 2010

    NASA Astrophysics Data System (ADS)

    Webb, Steve; Harris, Simon

    2010-12-01

    Physics in Medicine & Biology (PMB) awards its 'Citations Prize' to the authors of the original research paper that has received the most citations in the preceding five years (according to the Institute for Scientific Information (ISI)). The lead author of the winning paper is presented with the Rotblat Medal (named in honour of Professor Sir Joseph Rotblat who was the second—and longest serving—Editor of PMB, from 1961-1972). The winning co-authors each receive a certificate. Photograph of the 2010 Citations Prize winners The winning authors Fernando Rannou (left), George Alexandrakis (holding the Rotblat Medal) and Arion Chatziioannou (right). The winner of the 2010 Citations Prize for the paper which has received the most citations in the previous 5 years (2005-2009) is Tomographic bioluminescence imaging by use of a combined optical-PET (OPET) system: a computer simulation feasibility study Authors: George Alexandrakis, Fernando R Rannou and Arion F Chatziioannou Reference: George Alexandrakis et al 2005 Phys. Med. Biol. 50 4225-41 Discussion of the significance of the winning paper can be found on medicalphysicsweb (medicalphysicsweb.org/cws/article/research/44334). Our congratulations go to the winning authors. Steve Webb Editor-in-Chief Simon Harris Publisher

  2. Winners love winning and losers love money.

    PubMed

    Kassam, Karim S; Morewedge, Carey K; Gilbert, Daniel T; Wilson, Timothy D

    2011-05-01

    Salience and satisfaction are important factors in determining the comparisons that people make. We hypothesized that people make salient comparisons first, and then make satisfying comparisons only if salient comparisons leave them unsatisfied. This hypothesis suggests an asymmetry between winning and losing. For winners, comparison with a salient alternative (i.e., losing) brings satisfaction. Therefore, winners should be sensitive only to the relative value of their outcomes. For losers, comparison with a salient alternative (i.e., winning) brings little satisfaction. Therefore, losers should be drawn to compare outcomes with additional standards, which should make them sensitive to both relative and absolute values of their outcomes. In Experiment 1, participants won one of two cash prizes on a scratch-off ticket. Winners were sensitive to the relative value of their prizes, whereas losers were sensitive to both the relative and the absolute values of their prizes. In Experiment 2, losers were sensitive to the absolute value of their prize only when they had sufficient cognitive resources to engage in effortful comparison.

  3. Citations Prize 2013

    NASA Astrophysics Data System (ADS)

    Cherry, Simon; Ruffle, Jon

    2014-06-01

    Physics in Medicine and Biology (PMB) awards its 'Citations Prize' to the authors of the original research paper that has received the most citations in the preceding five years (according to the Institute for Scientific Information (ISI)). The lead author of the winning paper is presented with the Rotblat Medal (named in honour of Professor Sir Joseph Rotblat, a Nobel Prize winner who also was the second—and longest serving—Editor of PMB, from 1961-1972). The winner of the 2013 Citations Prize for the paper which has received the most citations in the previous five years (2008-2012) is Figure. Figure. Four of the prize winning authors. From left to right: Thomas Istel (Philips), Jens-Peter Schlomka (with medal, MorphoDetection), Ewald Roessl (Philips), and Gerhard Martens (Philips). Title: Experimental feasibility of multi-energy photon-counting K-edge imaging in pre-clinical computed tomography Authors: Jens Peter Schlomka1, Ewald Roessl1, Ralf Dorscheid2, Stefan Dill2, Gerhard Martens1, Thomas Istel1, Christian Bäumer3, Christoph Herrmann3, Roger Steadman3, Günter Zeitler3, Amir Livne4 and Roland Proksa1 Institutions: 1 Philips Research Europe, Sector Medical Imaging Systems, Hamburg, Germany 2 Philips Research Europe, Engineering & Technology, Aachen, Germany 3 Philips Research Europe, Sector Medical Imaging Systems, Aachen, Germany 4 Philips Healthcare, Global Research and Advanced Development, Haifa, Israel Reference: Schlomka et al 2008 Phys. Med. Biol. 53 4031-47 This paper becomes the first to win both this citations prize and also the PMB best paper prize (The Roberts Prize), which it won for the year 2008. Discussion of the significance of the winning paper can be found in this medicalphysicsweb article from the time of the Roberts Prize win (http://medicalphysicsweb.org/cws/article/research/39907). The author's enthusiasm for their prototype spectral CT system has certainly been reflected in the large number of citations the paper subsequently has

  4. L Prize Drives Technology Innovation, Energy Savings

    SciTech Connect

    2014-04-30

    Fact sheet that provides an overview of DOE's L Prize competition, which challenges industry to develop high-quality, high-efficiency SSL products to replace 60W incandescent and PAR38 halogen light bulbs, and highlights the competition's first 60W winner from Philips Lighting North America.

  5. Citations Prize 2011 Citations Prize 2011

    NASA Astrophysics Data System (ADS)

    Webb, Steve; Harris, Simon

    2011-12-01

    Physics in Medicine & Biology (PMB) awards its 'Citations Prize' to the authors of the original research paper that has received the most citations in the preceding five years (according to the Institute for Scientific Information (ISI)). The lead author of the winning paper is presented with the Rotblat Medal (named in honour of Professor Sir Joseph Rotblat who was the second—and longest serving—Editor of PMB, from 1961-1972). The winning co-authors each receive a certificate. Susan Hagness (left) receiving the Rotblat Medal from Robert Jeraj of PMB's Editorial Board (right) on behalf of Mariya Lazebnik. The winner of the 2011 Citations Prize for the paper which has received the most citations in the previous 5 years (2006-2010) is A large-scale study of the ultrawideband microwave dielectric properties of normal, benign and malignant breast tissues obtained from cancer surgeries Authors: Mariya Lazebnik, Dijana Popovic, Leah McCartney, Cynthia B Watkins, Mary J Lindstrom, Josephine Harter, Sarah Sewall, Travis Ogilvie, Anthony Magliocco, Tara M Breslin, Walley Temple, Daphne Mew, John H Booske, Michal Okoniewski and Susan C Hagness Reference: Mariya Lazebnik et al 2007 Phys. Med. Biol. 52 6093-115 Discussion of the significance of the winning paper can be found on medicalphysicsweb (medicalphysicsweb.org/cws/article/research/47814). Our congratulations go to the winning authors. Steve Webb Editor-in-Chief Simon Harris Publisher

  6. Citations Prize 2012 Citations Prize 2012

    NASA Astrophysics Data System (ADS)

    2013-01-01

    Physics in Medicine & Biology (PMB) awards its 'Citations Prize' to the authors of the original research paper that has received the most citations in the preceding five years (according to the Institute for Scientific Information (ISI)). The lead author of the winning paper is presented with the Rotblat Medal (named in honour of Professor Sir Joseph Rotblat who was the second—and longest serving—Editor of PMB, from 1961-1972). The authors of the winning paper. The authors of the winning paper. The winner of the 2012 Citations Prize for the paper which has received the most citations in the previous 5 years (2007-2011) is Image reconstruction in circular cone-beam computed tomography by constrained, total-variation minimization Authors: Emil Y Sidky and Xiaochuan Pan Reference: Emil Y Sidky and Xiaochuan Pan 2008 Phys. Med. Biol. 53 4777-807 Discussion of the significance of the winning paper can be found on medicalphysicsweb (medicalphysicsweb.org/cws/article/research/51868). Our congratulations go to the winning authors. Simon Cherry Editor-in-Chief Jon Ruffle Publisher

  7. Citations Prize 2009 Citations Prize 2009

    NASA Astrophysics Data System (ADS)

    Webb, Steve; Harris, Simon

    2009-12-01

    Physics in Medicine & Biology (PMB) awards its 'Citations Prize' to the authors of the original research paper that has received the most citations in the preceding five years (according to the Institute for Scientific Information (ISI)). The lead author of the winning paper is presented with the Rotblat Medal (named in honour of Professor Sir Joseph Rotblat who was the second—and longest serving—Editor of PMB, from 1961-1972). The winning co-authors each receive a certificate. Photograph of the 2009 Citations Prize winners Some of the winning authors with their certificates, and Christian Morel with the Rotblat Medal, at the award ceremony in Orsay, near Paris. From left to right are Corinne Groiselle, Lydia Maigne, David Brasse, Irène Buvat, Dimitris Visvikis, Giovanni Santin, Uwe Pietrzyk, Pierre-François Honore, Christian Morel, Sébastien Jan and Arion Chatziioannou. The winner of the 2009 Citations Prize for the paper which has received the most citations in the previous 5 years (2004-2008) is GATE: a simulation toolkit for PET and SPECT Authors: S Jan, G Santin, D Strul, S Staelens, K Assié, D Autret, S Avner, R Barbier, M Bardiès, P M Bloomfield, D Brasse, V Breton, P Bruyndonckx, I Buvat, A F Chatziioannou, Y Choi, Y H Chung, C Comtat, D Donnarieix, L Ferrer, S J Glick, C J Groiselle, D Guez, P-F Honore, S Kerhoas-Cavata, A S Kirov, V Kohli, M Koole, M Krieguer, D J van der Laan, F Lamare, G Largeron, C Lartizien, D Lazaro, M C Maas, L Maigne, F Mayet, F Melot, C Merheb, E Pennacchio, J Perez, U Pietrzyk, F R Rannou, M Rey, D R Schaart, C R Schmidtlein, L~Simon, T Y Song, J-M Vieira, D Visvikis, R Van de Walle, E Wieörs and C Morel Reference: S Jan et al 2004 Phys. Med. Biol. 49 4543-61 Since its publication in 2004 this article has received over 200 citations. This extremely high figure is a testament to the great influence and usefulness of the work to the nuclear medicine community. More discussion of the winning paper can be found on

  8. Volatility, house edge and prize structure of gambling games.

    PubMed

    Turner, Nigel E

    2011-12-01

    This study used simulations to examine the effect of prize structure on the outcome volatility and the number of winners of various game configurations. The two most common prize structures found in gambling games are even money payoff games (bet $1; win $2) found on most table games and multilevel prizes structures found in gambling machine games. Simulations were set up to examine the effect of prize structure on the long-term outcomes of these games. Eight different prize structures were compared in terms of the number of winners and volatility. It was found that the standard table game and commercial gambling machines produced fairly high numbers of short term winners (1 h), but few long term winners (50 h). It was found that the typical even money game set up produced the lowest level of volatility. Of the multilevel prize structures examined, the three simulations based on commercial gambling machines were the least volatile. The results are examined in terms of the pragmatics of game design.

  9. Challenges & Prizes

    EPA Pesticide Factsheets

    Prize competitions are open innovation tools championed by the America COMPETES ACT that EPA and other federal agencies use to attract fresh thinkers and creative problem solvers from across the country and the world.

  10. Prize Recipients

    NASA Astrophysics Data System (ADS)

    2007-09-01

    The John Bardeen Prize is awarded for theoretical work that has provided significant insights on the nature of superconductivity and has led to verifiable predictions. It is sponsored by the Dresdner Bank.

  11. Pennies from heaven? Conceptions and earmarking of lottery prize money.

    PubMed

    Hedenus, Anna

    2014-06-01

    The source of money has been shown to be important for how money is spent. In addition, sudden wealth is often associated with social and psychological risks. This article investigates if conceptions of lottery prize money--as a special kind of money--imply restrictions on how it can be spent. Analysis of interviews with lottery winners shows that interviewees use earmarking of the prize money as a strategy for avoiding the pitfalls associated with a lottery win. Conceptions of lottery prize money as 'a lot' or as 'a little', as shared or personal, and as an opportunity or a risk, influences the ends for which it is earmarked: for self-serving spending, a 'normal' living standard, paying off loans, saving for designated purposes, or for economic security and independence. Clearly defining and earmarking lottery prize money thus helps lottery winners construe their sudden wealth, not as a risk, but as 'pennies from heaven.'

  12. Arthroscopy Journal Prizes Are Major Decisions.

    PubMed

    Lubowitz, James H; Brand, Jefferson C; Provencher, Matthew T; Rossi, Michael J

    2016-01-01

    According to the Harvard Business Review, the optimal number of people in a decision-making group is no more than 8. Thus, it is no surprise that 18 Arthroscopy journal associate editors had difficulty making a major decision. In the end, 18 editors did successfully select the 2015 winner of the Best Comparative Study Prize. All studies have limitations, but from a statistical standpoint, the editors believe that the conclusions of the winning study are likely correct.

  13. PUBLISHER'S ANNOUNCEMENT: Journal of Physics A Best Paper Prize Journal of Physics A Best Paper Prize

    NASA Astrophysics Data System (ADS)

    Bender, Carl M.; Scriven, Neil

    2008-10-01

    We are delighted to announce the launch of the Journal of Physics A Best Paper Prize. There will be three prizes worth £250 each awarded annually for well written papers that make an outstanding contribution to the field. All articles published during the two years prior to the award, including Fast Track Communications, regular papers, topical reviews and special issue papers, can be considered for a prize. The papers will be judged in May each year using the criteria of novelty, achievement, impact and presentation. We would now like to welcome nominations for prizes to be awarded in 2009. Eligible articles must have been published in volume 40 (2007) or 41 (2008). Papers can be nominated by our Editorial Board members (who are exempt from the competition) or by readers of the journal. Please send an email to the journal editorial office (jphysa@iop.org) giving the publication details of the paper and stating (in no more than 1000 words) how it meets the criteria listed above. Authors cannot nominate their own papers. The closing date for nominations is 31 January 2009. The first set of awards will be announced following the 2009 Editorial Board meeting and winners will receive their prizes shortly thereafter. The winners' articles will be featured on the journal homepage and showcased in IOPSelect (http://www.iop.org/Select/). For further information please contact the editorial office (jphysa@iop.org). Carl M Bender Editor-in-Chief Neil Scriven Publisher

  14. What Is Community College Excellence? Lessons from the Aspen Prize

    ERIC Educational Resources Information Center

    Wyner, Joshua

    2012-01-01

    Over the past year, in a process to select the winner of the Aspen Prize for Community College Excellence, the Aspen Institute has convened national experts to define and determine how to measure "excellence," to identify community colleges with high levels of student success, and to help more community colleges understand what can be done to…

  15. Society News: RAS Fellows are honoured with awards; Patrick Moore Medal; Best theses win prizes; New Fellows

    NASA Astrophysics Data System (ADS)

    2011-08-01

    Congratulations to several Fellows of the RAS who have received prestigious awards this year. Congratulations to the winners of the annual prizes for the best PhD theses in astronomy and geophysics, awarded by the RAS and sponsored by Wiley-Blackwell. Winners receive a cheque for £1000, runners-up £50.

  16. 1989 Architectural Exhibition Winners.

    ERIC Educational Resources Information Center

    School Business Affairs, 1990

    1990-01-01

    Winners of the 1989 Architectural Exhibition sponsored annually by the ASBO International's School Facilities Research Committee include the Brevard Performing Arts Center (Melbourne, Florida), the Capital High School (Santa Fe, New Mexico), Gage Elementary School (Rochester, Minnesota), the Lakewood (Ohio) High School Natatorium, and three other…

  17. These Projects are WINNERS!

    ERIC Educational Resources Information Center

    Levi, Tricia

    1995-01-01

    Describes the winners of the Prentice Hall/National Middle School Association Teaching Team Awards (established to recognize exceptional interdisciplinary projects by middle school teaching teams). Students designed a new school, simulated a journey over the Oregon trail, conducted oral histories, and turned a local river into a learning…

  18. Top STS Winners Chosen.

    ERIC Educational Resources Information Center

    Science News, 1988

    1988-01-01

    Discusses the first, second, and third place winners in the 47th annual Westinghouse Science Talent Search. Describes student research projects dealing with electromagnetic and gravitational fields, cryptosporidiosis (a chronic diarrhea), and genetic factors of a nitrogen-fixing bacterium. (TW)

  19. In the Words of the Winners: The Newbery and Caldecott Medals, 2001-2010

    ERIC Educational Resources Information Center

    ALA Editions, 2011

    2011-01-01

    Winners of the most respected prizes in children's literature speak out in an exclusive collection of acceptance speeches, culled from the archives of the Association for Library Service to Children (ALSC) and "The Horn Book" magazine. Featuring authors and illustrators selected during the past 10 years, the book includes speeches by: (1) Neil…

  20. For Whom the Theories Toil. 1996 Reston Prize Winner.

    ERIC Educational Resources Information Center

    Green, Gaye Leigh

    1996-01-01

    Charts a step-by-step path from the pedagogical theories of teacher education to an effective and engaging method of classroom instruction using excerpts from Ernest Hemingway's "For Whom the Bell Tolls," as illustrative guideposts. Provides cogent, insightful, and productive ideas for improving classroom instruction. (MJP)

  1. Grand Prize Winner Profile: Manassas Park High School.

    ERIC Educational Resources Information Center

    Learning By Design, 2000

    2000-01-01

    Profiles the award-winning Manassas Park High School design that took a small school with limited land space and created small-scale learning communities from it. Interior and exterior photos are included. (GR)

  2. 2016 ISCB Overton Prize awarded to Debora Marks

    PubMed Central

    Fogg, Christiana N.; Kovats, Diane E.

    2016-01-01

    The International Society for Computational Biology (ISCB) recognizes the achievements of an early- to mid-career scientist with the Overton Prize each year. The Overton Prize was established to honor the untimely loss of Dr. G. Christian Overton, a respected computational biologist and founding ISCB Board member. Winners of the Overton Prize are independent investigators in the early to middle phases of their careers who are selected because of their significant contributions to computational biology through research, teaching, and service. 2016 will mark the fifteenth bestowment of the ISCB Overton Prize.  ISCB is pleased to confer this award the to Debora Marks, Assistant Professor of Systems Biology and director of the Raymond and Beverly Sackler Laboratory for Computational Biology at Harvard Medical School. PMID:27429747

  3. 2016 ISCB Overton Prize awarded to Debora Marks.

    PubMed

    Fogg, Christiana N; Kovats, Diane E

    2016-01-01

    The International Society for Computational Biology (ISCB) recognizes the achievements of an early- to mid-career scientist with the Overton Prize each year. The Overton Prize was established to honor the untimely loss of Dr. G. Christian Overton, a respected computational biologist and founding ISCB Board member. Winners of the Overton Prize are independent investigators in the early to middle phases of their careers who are selected because of their significant contributions to computational biology through research, teaching, and service. 2016 will mark the fifteenth bestowment of the ISCB Overton Prize.  ISCB is pleased to confer this award the to Debora Marks, Assistant Professor of Systems Biology and director of the Raymond and Beverly Sackler Laboratory for Computational Biology at Harvard Medical School.

  4. Nuclear Fusion prize laudation Nuclear Fusion prize laudation

    NASA Astrophysics Data System (ADS)

    Burkart, W.

    2011-01-01

    Clean energy in abundance will be of critical importance to the pursuit of world peace and development. As part of the IAEA's activities to facilitate the dissemination of fusion related science and technology, the journal Nuclear Fusion is intended to contribute to the realization of such energy from fusion. In 2010, we celebrated the 50th anniversary of the IAEA journal. The excellence of research published in the journal is attested to by its high citation index. The IAEA recognizes excellence by means of an annual prize awarded to the authors of papers judged to have made the greatest impact. On the occasion of the 2010 IAEA Fusion Energy Conference in Daejeon, Republic of Korea at the welcome dinner hosted by the city of Daejeon, we celebrated the achievements of the 2009 and 2010 Nuclear Fusion prize winners. Steve Sabbagh, from the Department of Applied Physics and Applied Mathematics, Columbia University, New York is the winner of the 2009 award for his paper: 'Resistive wall stabilized operation in rotating high beta NSTX plasmas' [1]. This is a landmark paper which reports record parameters of beta in a large spherical torus plasma and presents a thorough investigation of the physics of resistive wall mode (RWM) instability. The paper makes a significant contribution to the critical topic of RWM stabilization. John Rice, from the Plasma Science and Fusion Center, MIT, Cambridge is the winner of the 2010 award for his paper: 'Inter-machine comparison of intrinsic toroidal rotation in tokamaks' [2]. The 2010 award is for a seminal paper that analyzes results across a range of machines in order to develop a universal scaling that can be used to predict intrinsic rotation. This paper has already triggered a wealth of experimental and theoretical work. I congratulate both authors and their colleagues on these exceptional papers. W. Burkart Deputy Director General Department of Nuclear Sciences and Applications International Atomic Energy Agency, Vienna

  5. On the Human Aspect of Nobel Prize

    NASA Astrophysics Data System (ADS)

    Durand, G.

    1990-10-01

    One night, Nico invited for dinner all his postdoc and graduate students, in a German restaurant close to Harvard Square. Just before we were to pay for our meal, he told us: "Tomorrow, we shall know the Nobel prize winner. Can you people make a guess on his name?" All my colleagues nominated great physicists. In my turn, I suggested naively (and perhaps nationalistically) the name of Alfred Kastler who had been my thesis adviser. "Come on," joked Nico, "I know a lot of physicists who would deserve it much better.."

  6. PUBLISHER'S ANNOUNCEMENT: Journal of Physics A Best Paper Prize

    NASA Astrophysics Data System (ADS)

    2008-11-01

    We are delighted to announce the launch of the Journal of Physics A Best Paper Prize. There will be three prizes worth £250 each awarded annually for well written papers that make an outstanding contribution to the field. All articles published during the two years prior to the award, including Fast Track Communications, regular papers, topical reviews and special issue papers, can be considered for a prize. The papers will be judged in late Spring each year using the criteria of novelty, achievement, impact and presentation. We would now like to welcome nominations for prizes to be awarded in 2009. Eligible articles must have been published in volume 39 (2007) or 40 (2008). Papers can be nominated by our Editorial Board members (who are exempt from the competition) or by readers of the journal. Please send an email to the journal editorial office (jphysa@iop.org) giving the publication details of the paper and stating (in no more than 1000 words) how it meets the criteria listed above. Authors cannot nominate their own papers. The closing date for nominations is 31 January 2009. The first set of awards will be announced following the 2009 Editorial Board meeting and winners will receive their prizes shortly thereafter. The winners' articles will be featured on the journal homepage and showcased in IOPSelect (http://www.iop.org/Select/). For further information please contact the editorial office (jphysa@iop.org). Carl M Bender Editor-in-Chief Neil Scriven Publisher

  7. PUBLISHER'S ANNOUNCEMENT: Journal of Physics A Best Paper Prize

    NASA Astrophysics Data System (ADS)

    2008-10-01

    We are delighted to announce the launch of the Journal of Physics A Best Paper Prize. There will be three prizes worth £250 each awarded annually for well written papers that make an outstanding contribution to the field. All articles published during the two years prior to the award, including Fast Track Communications, regular papers, topical reviews and special issue papers, can be considered for a prize. The papers will be judged in late Spring each year using the criteria of novelty, achievement, impact and presentation. We would now like to welcome nominations for prizes to be awarded in 2009. Eligible articles must have been published in volume 39 (2007) or 40 (2008). Papers can be nominated by our Editorial Board members (who are exempt from the competition) or by readers of the journal. Please send an email to the journal editorial office (jphysa@iop.org) giving the publication details of the paper and stating (in no more than 1000 words) how it meets the criteria listed above. Authors cannot nominate their own papers. The closing date for nominations is 31 January 2009. The first set of awards will be announced following the 2009 Editorial Board meeting and winners will receive their prizes shortly thereafter. The winners' articles will be featured on the journal homepage and showcased in IOPSelect (http://www.iop.org/Select/). For further information please contact the editorial office (jphysa@iop.org). Carl M Bender Editor-in-Chief Neil Scriven Publisher

  8. PUBLISHER'S ANNOUNCEMENT: Journal of Physics A Best Paper Prize

    NASA Astrophysics Data System (ADS)

    2008-10-01

    We are delighted to announce the launch of the Journal of Physics A Best Paper Prize. There will be three prizes worth £250 each awarded annually for well written papers that make an outstanding contribution to the field. All articles published during the two years prior to the award, including Fast Track Communications, regular papers, topical reviews and special issue papers, can be considered for a prize. The papers will be judged in May each year using the criteria of novelty, achievement, impact and presentation. We would now like to welcome nominations for prizes to be awarded in 2009. Eligible articles must have been published in volume 40 (2007) or 41 (2008). Papers can be nominated by our Editorial Board members (who are exempt from the competition) or by readers of the journal. Please send an email to the journal editorial office (jphysa@iop.org) giving the publication details of the paper and stating (in no more than 1000 words) how it meets the criteria listed above. Authors cannot nominate their own papers. The closing date for nominations is 31 January 2009. The first set of awards will be announced following the 2009 Editorial Board meeting and winners will receive their prizes shortly thereafter. The winners' articles will be featured on the journal homepage and showcased in IOPSelect (http://www.iop.org/Select/). For further information please contact the editorial office (jphysa@iop.org). Carl M Bender Editor-in-Chief Neil Scriven Publisher

  9. IT Summit 2010 - Award Winners

    NASA Video Gallery

    NASA CIO Linda Cureton announces this year’s IT Summit award winners. These awards recognize achievement in six key areas for contributions that have aided in NASA achieving mission goals and objec...

  10. In Sciences, the Reflected Prestige of the Nobel Prize Extends Far Beyond Anything Its Creator Imagined.

    ERIC Educational Resources Information Center

    McDonald, Kim

    1987-01-01

    As the ultimate symbol of excellence, the Nobel Prize has had a tremendous effect on scholars, institutions, and national pride. Topics discussed include: recruitment and fund raising, salaries and other perks, "raids" from other institutions, students seeking out winners, publication declines, etc. (MLW)

  11. Stellar students win fantastic prizes

    NASA Astrophysics Data System (ADS)

    2008-05-01

    will meet astronomers and be present during a night of observations. Learning that they won, the team was enthusiastic: "We are very pleased to hear this fantastic news and are looking forward to the trip!" Another winner was Marta Kotarba, with her teacher Grzegorz Sęk, from the school IV Liceum Ogólnokształcące im. Tadeusza Kościuszki, Poland. Her prize is a trip to the Hispano-German Astronomical Observatory of Calar Alto in Almeria, Spain, kindly donated by the Spanish Council for Scientific Research. Marta's project "Galaxy Zoo and I" tells how she joined the website "Galaxy Zoo" to study galaxies and help astronomical researchers understand the structure of the Universe. Galaxy Zoo volunteers classify galaxies into different types, such as spiral or elliptical - a task much more easily done by humans than computers. Marta explains that the project "is like an adventure to me. Galaxy Zoo gives me abilities to enlarge my knowledge about the Universe and to gain new skills." Her winning entry also shows how anyone can get involved in the world of real astronomical research, simply by using the Internet. A third winner, of a trip to Königsleiten Observatory in Austria, is Andreia Nascimento with her teacher Leonor Cabral, from Escola Secundária da Cidadela in Portugal. Her project, on "Hunting for Open Star Clusters" near young stars, used data from the robotic Faulkes Telescope in Hawaii, which is used for research-based science education. "Catch a Star" also includes an artwork competition, for which students created artwork with an astronomical theme. This competition, through which students can get involved with astronomy even outside of science classes, has become increasingly popular, with over one thousand entries this year from around the world. Not only were prizes awarded by public votes in a web gallery, but special prizes were awarded by Garry Harwood, a Fellow and life member of the International Association of Astronomy Artists. Harwood said: "It

  12. EPA Announces Nutrient Recycling Challenge Winners

    EPA Pesticide Factsheets

    WASHINGTON - Today, the U.S. Environmental Protection Agency (EPA) announced the winners of Phase I of the Nutrient Recycling Challenge-a competition to develop affordable technologies to recycle nutrients from livestock manure. The winners received

  13. Positron microscopy

    SciTech Connect

    Hulett, L.D. Jr.; Xu, J.

    1995-02-01

    The negative work function property that some materials have for positrons make possible the development of positron reemission microscopy (PRM). Because of the low energies with which the positrons are emitted, some unique applications, such as the imaging of defects, can be made. The history of the concept of PRM, and its present state of development will be reviewed. The potential of positron microprobe techniques will be discussed also.

  14. Newbery Winners Reflect Societal Trends.

    ERIC Educational Resources Information Center

    Newton, Jennifer A.

    1986-01-01

    Social trends of the last 35 years are traced through an examination of Newbery Medal winners from 1951 to 1985. Idealism and realism in children's literature, the sex of the main characters, and the effects of changes in the publishing industry on children's books are discussed. (EM)

  15. Breast Cancer Startup Challenge winners

    Cancer.gov

    Ten winners of a world-wide competition to bring emerging breast cancer research technologies to market faster were announced today by the Avon Foundation for Women, in partnership with NCI and the Center for Advancing Innovation (CAI). Avon is providing

  16. MIT Clean Energy Prize: Final Technical Report May 12, 2010 - May 11, 2011

    SciTech Connect

    Snyder, Chris; Campbell, Georgina; Salony, Jason; Aulet, Bill

    2011-08-09

    The MIT Clean Energy Prize (MIT CEP) is a venture creation and innovation competition to encourage innovation in the energy space, specifically with regard to clean energy. The Competition invited student teams from any US university to submit student-led ventures that demonstrate a high potential of successfully making clean energy more affordable, with a positive impact on the environment. By focusing on student ventures, the MIT CEP aims to educate the next generation of clean energy entrepreneurs. Teams receive valuable mentoring and hard deadlines that complement the cash prize to accelerate development of ventures. The competition is a year-long educational process that culminates in the selection of five category finalists and a Grand Prize winner and the distribution of cash prizes to each of those teams. Each entry was submitted in one of five clean energy categories: Renewables, Clean Non-Renewables, Energy Efficiency, Transportation, and Deployment.

  17. Wins, winning and winners: the commercial advertising of lottery gambling.

    PubMed

    McMullan, John L; Miller, Delthia

    2009-09-01

    This study analyzed a sample of 920 lottery ads that were placed or played in Atlantic Canada from January 2005 to December 2006. A content analysis, involving quantitative and qualitative techniques, was conducted to examine the design features, exposure profiles and focal messages of these ads and to explore the connections between lottery advertising and consumer culture. We found that there was an "ethos of winning" in these commercials that provided the embedded words, signs, myths, and symbols surrounding lottery gambling and conveyed a powerful imagery of plentitude and certitude in a world of potential loss where there was little reference to the actual odds of winning. The tangible and emotional qualities in the ads were especially inviting to young people creating a positive orientation to wins, winning and winners, and lottery products that, in turn, reinforced this form of gambling as part of youthful consumption practices. We concluded that enticing people with the prospects of huge jackpots, attractive consumer goods and easy wins, showcasing top prize winners, and providing dubious depictions that winning is life-changing was narrow and misleading and exploited some of the factors associated with at-risk gambling.

  18. The 6th FDR prize

    NASA Astrophysics Data System (ADS)

    Funakoshi, Mitsuaki

    2013-06-01

    -liquid interfaces are shown. Finally, the scattering of sound waves by water droplets is discussed. In thick fog, the sound coming from a distance becomes faint due to the sound-scattering effects of micro water droplets. The author gives an example of successfully solving such an issue by the FDLBM. It is highly admirable that the author developed the new FDLBM for aero-acoustic issues and has summarized it with sub-schemes to overcome several difficulties of engineering aeroacoustics in this review. It will certainly contribute to further development of fluid dynamics through computational aero-acoustics. Consequently, this paper was selected as the winner of the sixth FDR prize.

  19. EPA Challenges & Prizes

    EPA Pesticide Factsheets

    EPA is a government leader in tapping the power of contributions from the public to help solve difficult problems that affect the environment and public health. Prize competitions allow federal agencies to pay only for successful solutions.

  20. Mortality and immortality: the Nobel Prize as an experiment into the effect of status upon longevity.

    PubMed

    Rablen, Matthew D; Oswald, Andrew J

    2008-12-01

    It has been known for centuries that the rich and famous have longer lives than the poor and ordinary. Causality, however, remains trenchantly debated. The ideal experiment would be one in which extra status could somehow be dropped upon a sub-sample of individuals while those in a control group of comparable individuals received none. This paper attempts to formulate a test in that spirit. It collects 19th-century birth data on science Nobel Prize winners. Correcting for potential biases, we estimate that winning the Prize, compared to merely being nominated, is associated with between 1 and 2 years of extra longevity.

  1. Molecular approaches to understanding neural network plasticity and memory: the Kavli Prize Inaugural Symposium on Neuroscience.

    PubMed

    Sander, M; Bergersen, L H; Storm-Mathisen, J

    2009-11-10

    The Kavli Prizes were awarded for the first time in Oslo, Norway on September 9, 2008 to seven of the world's most prominent scientists in astrophysics, nanoscience and neuroscience. The astrophysics prize was awarded jointly to Maarten Schmidt, of the California Institute of Technology, USA, and Donald Lynden-Bell, of Cambridge University, UK; the nanoscience prize was awarded jointly to Louis E. Brus, of Columbia University, USA, and Sumio Iijima, of Meijo University, Japan; and the neuroscience prize was awarded jointly to Pasko Rakic, of the Yale University School of Medicine, USA, Thomas Jessell, of Columbia University, USA, and Sten Grillner, of the Karolinska Institute, Sweden. The Kavli Prize is a joint venture of the Kavli Foundation, the Norwegian Academy of Science and Letters, and the Norwegian Ministry of Education and Research. The Kavli Prize Inaugural Symposium on Neuroscience was held at the University of Oslo on 8 September, 2008, organized by L.H. Bergersen, E. Moser M.-B. Moser, and J. Storm-Mathisen. At this Symposium, seven leading neuroscientists described their groundbreaking work, which encompasses some of the most important recent advances in the field of neuroscience, from molecule to synapse to network to behavior. The Symposium was a fitting tribute to Fred Kavli's vision of neuroscience as an outstanding area of progress, and to the achievements of the winners of the first Kavli Prize in Neuroscience. The main points of the Symposium presentations are summarized below.

  2. The 2010 Broad Prize

    ERIC Educational Resources Information Center

    Education Digest: Essential Readings Condensed for Quick Review, 2011

    2011-01-01

    A new data analysis, based on data collected as part of The Broad Prize process, provides insights into which large urban school districts in the United States are doing the best job of educating traditionally disadvantaged groups: African-American, Hispanics, and low-income students. Since 2002, The Eli and Edythe Broad Foundation has awarded The…

  3. EDITORIAL: Annual prizes for best papers

    NASA Astrophysics Data System (ADS)

    2007-07-01

    2006 Roberts Prize The publishers of Physics in Medicine and Biology (PMB) in association with the Institute of Physics and Engineering in Medicine (IPEM) jointly award an annual prize for an article published in PMB during the previous year. The following ten articles, listed below in chronological order, were rated the best of 2006 based on the (two or three) referees' assessments: D W Mundy et al 2006 Radiation binary targeted therapy for HER-2 positive breast cancers: assumptions, theoretical assessment and future directions Phys. Med. Biol. 51 1377-91 Y Yang et al 2006 Investigation of optical coherence tomography as an imaging modality in tissue engineering Phys. Med. Biol. 51 1649-59 M Krämer and M Scholz 2006 Rapid calculation of biological effects in ion radiotherapy Phys. Med. Biol. 51 1959-70 P Crespo et al 2006 On the detector arrangement for in-beam PET for hadron therapy monitoring Phys. Med. Biol. 51 2143-63 R J Senden et al 2006 Polymer gel dosimeters with reduced toxicity: a preliminary investigation of the NMR and optical dose-response using different monomers Phys. Med. Biol. 51 3301-14 J Wang et al 2006 FDTD calculation of whole-body average SAR in adult and child models for frequencies from 30 MHz to 3 GHz Phys. Med. Biol. 51 4119-27 C A T Van den Berg et al 2006 The use of MR B+1 imaging for validation of FDTD electromagnetic simulations of human anatomies Phys. Med. Biol. 51 4735-46 S Qin and K W Ferrara 2006 Acoustic response of compliable microvessels containing ultrasound contrast agents Phys. Med. Biol. 51 5065-88 R Kramer et al 2006 Skeletal dosimetry in the MAX06 and the FAX06 phantoms for external exposure to photons based on vertebral 3D-microCT images Phys. Med. Biol. 51 6265-89 R Leiderman et al 2006 Coupling between elastic strain and interstitial fluid flow: ramifications for poroelastic imaging Phys. Med. Biol. 51 6291-313 An IPEM college of jurors then assessed and rated these papers in order to choose a winner. We have much

  4. EDITORIAL: Annual prizes for best papers

    NASA Astrophysics Data System (ADS)

    2006-09-01

    oxygen saturation using pulsed near-infrared photoacoustic spectroscopy: accuracy and resolution Phys. Med. Biol. 50 4409-28 Z Cao et al 2005 Optimal number of pinholes in multi-pinhole SPECT for mouse brain imaging---a simulation study Phys. Med. Biol. 50 4609-24 R Dharmakumar et al 2005 A novel microbubble construct for intracardiac or intravascular MR manometry: a theoretical study Phys. Med. Biol. 50 4745-62 R Chopra et al 2005 Method for MRI-guided conformal thermal therapy of prostate with planar transurethral ultrasound heating applicators Phys. Med. Biol. 50 4957-75 The IPEM Publications Committee then assessed and rated these papers in order to choose a winner. We have much pleasure in advising readers that the 2005 Roberts Prize is awarded to: J S Dysart and M S Patterson 2005 Characterization of Photofrin photobleaching for singlet oxygen dose estimation during photodynamic therapy of MLL cells in vitro Phys. Med. Biol. 50 2597-616 2006 Prize for the Highest Cited Paper The annual prize for the most highly cited paper is awarded by the journal publishers to the article published in PMB that has received the most citations1 in the previous 5 years (in this case for the period 2001 to 2005 inclusive). We have much pleasure in advising readers that the 2006 prize is awarded to: P J Keall, V R Kini, S S Vedam and R Mohan 2001 Motion adaptive x-ray therapy: a feasibility study Phys. Med. Biol. 46 1-10 Simon Harris, Publisher Steve Webb, Editor-in-Chief 1 Figures taken from Thomson/ISI

  5. Positron Physics

    NASA Technical Reports Server (NTRS)

    Drachman, Richard J.

    2003-01-01

    I will give a review of the history of low-energy positron physics, experimental and theoretical, concentrating on the type of work pioneered by John Humberston and the positronics group at University College. This subject became a legitimate subfield of atomic physics under the enthusiastic direction of the late Sir Harrie Massey, and it attracted a diverse following throughout the world. At first purely theoretical, the subject has now expanded to include high brightness beams of low-energy positrons, positronium beams, and, lately, experiments involving anti-hydrogen atoms. The theory requires a certain type of persistence in its practitioners, as well as an eagerness to try new mathematical and numerical techniques. I will conclude with a short summary of some of the most interesting recent advances.

  6. Why do winners keep winning? Androgen mediation of winner but not loser effects in cichlid fish

    PubMed Central

    Oliveira, Rui F.; Silva, Ana; Canário, Adelino V.M.

    2009-01-01

    Animal conflicts are influenced by social experience such that a previous winning experience increases the probability of winning the next agonistic interaction, whereas a previous losing experience has the opposite effect. Since androgens respond to social interactions, increasing in winners and decreasing in losers, we hypothesized that socially induced transient changes in androgen levels could be a causal mediator of winner/loser effects. To test this hypothesis, we staged fights between dyads of size-matched males of the Mozambique tilapia (Oreochromis mossambicus). After the first contest, winners were treated with the anti-androgen cyproterone acetate and losers were supplemented with 11-ketotestosterone. Two hours after the end of the first fight, two contests were staged simultaneously between the winner of the first fight and a naive male and between the loser of first fight and another naive male. The majority (88%) of control winners also won the second interaction, whereas the majority of control losers (87%) lost their second fight, thus confirming the presence of winner/loser effects in this species. As predicted, the success of anti-androgen-treated winners in the second fight decreased significantly to chance levels (44%), but the success of androgenized losers (19%) did not show a significant increase. In summary, the treatment with anti-androgen blocks the winner effect, whereas androgen administration fails to reverse the loser effect, suggesting an involvement of androgens on the winner but not on the loser effect. PMID:19324741

  7. Why do winners keep winning? Androgen mediation of winner but not loser effects in cichlid fish.

    PubMed

    Oliveira, Rui F; Silva, Ana; Canário, Adelino V M

    2009-06-22

    Animal conflicts are influenced by social experience such that a previous winning experience increases the probability of winning the next agonistic interaction, whereas a previous losing experience has the opposite effect. Since androgens respond to social interactions, increasing in winners and decreasing in losers, we hypothesized that socially induced transient changes in androgen levels could be a causal mediator of winner/loser effects. To test this hypothesis, we staged fights between dyads of size-matched males of the Mozambique tilapia (Oreochromis mossambicus). After the first contest, winners were treated with the anti-androgen cyproterone acetate and losers were supplemented with 11-ketotestosterone. Two hours after the end of the first fight, two contests were staged simultaneously between the winner of the first fight and a naive male and between the loser of first fight and another naive male. The majority (88%) of control winners also won the second interaction, whereas the majority of control losers (87%) lost their second fight, thus confirming the presence of winner/loser effects in this species. As predicted, the success of anti-androgen-treated winners in the second fight decreased significantly to chance levels (44%), but the success of androgenized losers (19%) did not show a significant increase. In summary, the treatment with anti-androgen blocks the winner effect, whereas androgen administration fails to reverse the loser effect, suggesting an involvement of androgens on the winner but not on the loser effect.

  8. Malcolm Baldrige National Quality Award winners 1989

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The 1989 Malcolm Baldrige award winners - Milliken and Company; and Xerox Business Products and Services are highlighted in this video. Their strategies for producing quality products are discussed, along with their applications and importance in today's competitive workplace.

  9. Science Talent Search: Top 40 Winners

    ERIC Educational Resources Information Center

    Science News, 1977

    1977-01-01

    Briefly discusses the 36th annual Science Talent Search, in which high school students conducted independent research to compete for college scholarships. Lists the 40 winners, their states of residence, and their high schools. (MLH)

  10. Nobel Prize in Physiology or Medicine

    MedlinePlus

    ... Educational - Medicine Prize Related The Nobel Prize in Physiology or Medicine has been awarded to people and ... this page MLA style: "The Nobel Prize in Physiology or Medicine – Educational". Nobelprize.org. Nobel Media ...

  11. In Brief: Trieste Prize nominations

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2007-12-01

    Nominations for the 2008 Trieste Science Prize in Earth, space, ocean, and atmospheric sciences and in engineering sciences are being accepted through 31 January 2008. The prize has been established to give international recognition and visibility to outstanding scientific achievements made by scientists from developing countries. Candidates must be nationals of developing countries, and the prizes will only be awarded to individuals for scientific research of outstanding international merit carried out at institutions in developing countries. The prizes, each of which carries a US$50,000 monetary award, are administered by the Academy of Sciences for the Developing World (TWAS) and funded by Illycaffè in collaboration with the Trieste (Italy) Town Council and the Trieste International Foundation for Scientific Progress and Freedom. For more information, contact the TWAS Secretariat at prizes@twas.org.

  12. The 3K Blackbody Radiation, 'Stored' & 'Frozen' Light, 'Viscous Optical Molasses' as Effects of the Electron Positron Lattice (EPOLA) Structure of Our "Vacuum" Space

    NASA Astrophysics Data System (ADS)

    Simhony, Menahem

    2002-05-01

    In the EPOLA model of space [1] the mysterious 3K blackbody radiation of the sky is due to random thermal vibrations of the electrons and positrons, bound in the epola. They also cause the zero-point motion of helium atoms, a Brownian Motion analog. The temperature T of our epola region is therefore 3K. In space regions with more hot stars, more nuclear activity, T is higher and they may create the mystery of gray matter. Epola regions below 3K are observed as mysterious dark matter. The gray and dark matter regions are considered to constitute 90 percent of the mass of the universe. The 1997 Nobel Prize winners' "Optical Molasses" at micro-K T's are also explained by the epola model, as well as the 'stored', 'frozen' light effects, observed in 1999-2001. References: 1. M.Simhony, Invitation to the Natural Physics of Matter, Space, and Radiation, World Scientific, 1994 (292 pp), ISBN 981-02-1649-1. See the website: www.word1.co.il/physics .

  13. Winners of student essay contest receive awards

    NASA Technical Reports Server (NTRS)

    1999-01-01

    George Meguiar (left) presents a scholarship award to Kyla Davis Horn, of Cocoa Beach, one of the winners of an essay contest related to the 30th Anniversary of Apollo 11. Meguiar and George English (second from right) head the Apollo 11 Commemoration Association who sponsored the contest in conjunction with Florida Today newspaper. The other scholarship winner is Kyle Rukaczewski, of Satellite Beach (far right). A third winner, Jason Gagnon, of Viera, was unable to attend. The presentation was made at the Apollo/Saturn V Center during an anniversary banquet that honored all the people who made the Apollo Program possible. Special guests included former Apollo astronauts Neil Armstrong, Edwin 'Buzz' Aldrin, Gene Cernan and Walt Cunningham, who shared their experiences with the audience.

  14. High School Teachers Win ACS Prizes

    NASA Astrophysics Data System (ADS)

    Editorial Staff, Jce

    2009-07-01

    William E. Snyder is the 2009 winner of the ACS Division of Chemical Education Central Region Award for Excellence in High School Teaching; Sally Mitchell is the winner of the 2009 James Bryant Conant Award in High School Chemistry Teaching.

  15. Optics pioneers scoop Nobel prize

    NASA Astrophysics Data System (ADS)

    Banks, Michael

    2009-11-01

    Three physicists who carried out pioneering work in former industrial research labs have picked up this year's Nobel Prize for Physics. One half of the SEK 10m prize has been awarded to Charles Kao, 75, for his work at the UK-based Standard Telephones and Cables (STC) on the transmission of light in optical fibres, which underpinned the telecommunications revolution. The other half of the prize is shared between Willard Boyle, 85, and George Smith, 79, of Bell Laboratories in New Jersey, US, for inventing the charge-coupled device (CCD) - an imaging semiconductor circuit that forms the basis of most digital cameras.

  16. 2012 Cliff Weiss Memorial Essay Contest Winners

    ERIC Educational Resources Information Center

    Techniques: Connecting Education and Careers (J3), 2012

    2012-01-01

    This article presents the winners of the 2012 Cliff Weiss Memorial Essay Contest. They are Naim Owens from Washington, DC, and Colissa Menke from Warrensburg, Missouri. The 2012 essay topic is "How do you feel CTE prepares individuals, including yourself, for a future career?"

  17. Europlanet Prize for Public Engagement

    NASA Astrophysics Data System (ADS)

    Fouchet, Thierry

    2016-10-01

    The Europlanet Prize for Public Engagement with Planetary Science is awarded annually. Through the Prize, Europlanet aims to recognise achievements in engaging European citizens with planetary science and to raise the profile of outreach within the scientific community. It is awarded to individuals or groups who have developed innovative practices in planetary science communication and whose efforts have significantly contributed to a wider public engagement with planetary science.

  18. Haagen-Smit Prize 2015

    NASA Astrophysics Data System (ADS)

    2016-01-01

    The Executive Editors and the Publisher of Atmospheric Environment take great pleasure in announcing the 2015 ''Haagen-Smit Prize", designed to recognize outstanding papers published in Atmospheric Environment. The Prize is named in honor of Prof. Arie Jan Haagen-Smit, a pioneer in the field of air pollution and one of the first editors of the International Journal of Air Pollution, a predecessor to Atmospheric Environment.

  19. Haagen-Smit Prize 2014

    NASA Astrophysics Data System (ADS)

    2015-02-01

    The Executive Editors and the Publisher of Atmospheric Environment take great pleasure in announcing the 2014 ''Haagen-Smit Prize", designed to recognize outstanding papers published in Atmospheric Environment. The Prize is named in honor of Prof. Arie Jan Haagen-Smit, a pioneer in the field of air pollution and one of the first editors of the International Journal of Air Pollution, a predecessor to Atmospheric Environment.

  20. Haagen-Smit Prize 2016

    NASA Astrophysics Data System (ADS)

    Singh, Hanwant

    2017-03-01

    The Executive Editors and the Publisher of Atmospheric Environment take great pleasure in announcing the 2016 "Haagen-Smit Prize", designed to recognize outstanding papers published in Atmospheric Environment. The Prize is named in honor of Prof. Arie Jan Haagen-Smit, a pioneer in the field of air pollution and one of the first editors of the International Journal of Air Pollution, a predecessor to Atmospheric Environment.

  1. Youyou Tu: significance of winning the 2015 Nobel Prize in Physiology or Medicine

    PubMed Central

    Liu, Wenxiu

    2016-01-01

    Youyou Tu, a female scientist at the China Academy of Traditional Chinese Medicine in Beijing, is the first Chinese winner of the Nobel Prize in Physiology or Medicine. Based on the study of recipes which had been used for thousands of years to treat fever, Tu’s group discovered that the plant artemesia annua, sweet wormwood, showed substantial inhibition of rodent malaria parasites. Her achievement and experience have inspired other researchers and emphasized the development of traditional Chinese medicine. Her award has led to a heated discussion about scientific research investment, fair treatment of research staff, and intellectual property right (IPR) protection in China. PMID:26885485

  2. Youyou Tu: significance of winning the 2015 Nobel Prize in Physiology or Medicine.

    PubMed

    Liu, Wenxiu; Liu, Yue

    2016-02-01

    Youyou Tu, a female scientist at the China Academy of Traditional Chinese Medicine in Beijing, is the first Chinese winner of the Nobel Prize in Physiology or Medicine. Based on the study of recipes which had been used for thousands of years to treat fever, Tu's group discovered that the plant artemesia annua, sweet wormwood, showed substantial inhibition of rodent malaria parasites. Her achievement and experience have inspired other researchers and emphasized the development of traditional Chinese medicine. Her award has led to a heated discussion about scientific research investment, fair treatment of research staff, and intellectual property right (IPR) protection in China.

  3. The mantle of the heavens: Reflections on the 2014 Nobel Prize for medicine or physiology.

    PubMed

    Morris, Richard G M

    2015-06-01

    The award of the Nobel Prize in Medicine or Physiology in 2014 for the discovery of place and grid cells was both a personal award to three great scientists and also a mark of the maturity of systems neuroscience as a discipline. This article offers both personal and scientific reflections on these discoveries, detailing both how getting to know all three winners had an impact on my life and the research questions that we shared in common work together. It ends with brief reflections on three important outstanding questions.

  4. 2006 Foster G. McGaw Prize winner: memorial healthcare system, Hollywood, Fla.

    PubMed

    Thrall, Terese Hudson

    2007-04-01

    Memorial Healthcare System in Hollywood, Fla., is receiving well-deserved national recognition for its myriad community benefit programs, from public housing improvements to prenatal care for uninsured mothers-to-be.

  5. Creativity in Early and Established Career: Insights into Multi-Level Drivers from Nobel Prize Winners

    ERIC Educational Resources Information Center

    Eubanks, Dawn L.; Palanski, Michael E.; Swart, Juani; Hammond, Michelle M.; Oguntebi, Joy

    2016-01-01

    The freedom to try new things plays a vital role for employees engaging in creative endeavors. This freedom can be influenced by one's relationship with her supervisor, relationship with her team, and various work pressures. One of the first steps to reaching creative output is to have a playful attitude toward work where there is encouragement…

  6. 77 FR 64851 - Announcement Date Postponed for the Grand Prize Winner Announcement for the America COMPETES...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-23

    ... Reauthorization Act of 2011: Project REACH Homelessness Mobile App Contest AGENCY: Department of Veterans Affairs... the Federal Register (77 FR 16895) to announce the launch of VA's Project REACH Homelessness Mobile... opportunity to receive recognition for their dedication and efforts to end Veteran homelessness. This...

  7. The First Printz Award Designations: Winners All.

    ERIC Educational Resources Information Center

    Dimmitt, Jean Pollard

    2001-01-01

    Explains a major new book award, the Michael L. Printz Award honoring the best young adult book. Discusses the first prize-winning book: "Monster" by Walter Dean Myers, and three honor books. Discusses how these books are unusual and outstanding examples of young adult literature--structurally sophisticated with memorable characters who deal with…

  8. Blue Ribbon Web Sites Contest Winners.

    ERIC Educational Resources Information Center

    Southworth, Samuel A.

    2001-01-01

    Presents a collection of prize-winning Web sites created by K-8 teachers nationwide. Some of the unique features of the Web sites include an online student-written newspaper; a sing-along section; a chronicle of the past 3 years of classes to see how the classes have evolved; and student art and writing projects. (SM)

  9. Positron Interactions with Atoms and Ions

    NASA Technical Reports Server (NTRS)

    Bhatia, Anand K.

    2012-01-01

    Dirac, in 1928, combining the ideas of quantum mechanics and the ideas of relativity invented the well-known relativistic wave equation. In his formulation, he predicted an antiparticle of the electron of spin n-bar/2. He thought that this particle must be a proton. Dirac published his interpretation in a paper 'A theory of electrons and protons.' It was shown later by the mathematician Hermann Weyl that the Dirac theory was completely symmetric between negative and positive particles and the positive particle must have the same mass as that of the electron. In his J. Robert Oppenheimer Memorial Prize Acceptance Speech, Dirac notes that 'Blackett was really the first person to obtain hard evidence for the existence of a positron but he was afraid to publish it. He wanted confirmation, he was really over cautious.' Positron, produced by the collision of cosmic rays in a cloud chamber, was detected experimentally by Anderson in 1932. His paper was published in Physical Review in 1933. The concept of the positron and its detection were the important discoveries of the 20th century. I have tried to discuss various processes involving interactions of positrons with atoms and ions. This includes scattering, bound states and resonances. It has not been possible to include the enormous work which has been carried out during the last 40 or 50 years in theory and measurements.

  10. Winners of student essay contest receive awards

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the Apollo/Saturn V Center, George Meguiar (center left) and George English (center right) present scholarships to two students who entered an essay contest in conjunction with the 30th Anniversary of Apollo 11. The winners shown are Kyla Davis Horn, of Cocoa Beach, and Kyle Rukaczewski, of Satellite Beach. A third winner, Jason Gagnon, of Viera, was unable to attend. Meguiar and English head the Apollo 11 Commemoration Association which sponsored the contest in conjunction with Florida Today newspaper. The presentation was made at the Apollo/Saturn V Center during an anniversary banquet that honored all the people who made the Apollo Program possible. Special guests included former Apollo astronauts Neil Armstrong, Edwin 'Buzz' Aldrin, Gene Cernan and Walt Cunningham, who shared their experiences with the audience.

  11. Mrs. Chandrasekhar poses with contest winners

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Mrs. Lalitha Chandrasekhar (left), wife of the late Indian- American Nobel Laureate Subrahmanyan Chandrasekhar, poses with a model of the Chandra X-ray Observatory and the winners of the contest to rename the telescope in the TRW Media Hospitality Tent at the NASA Press Site at KSC. The winners of the contest are Jatila van der Veen (center), academic coordinator and lecturer, Physics Dept., University of Santa Barbara, Calif., and Tyrel Johnson (right), high school student, Laclede, Idaho. The name 'Chandra,' a shortened version of Chandrasekhar's name which he preferred among friends and colleagues, was chosen to honor the Nobel Laureate. 'Chandra' also means 'Moon' or 'luminous' in Sanskrit. The observatory is scheduled to be launched aboard Columbia on Space Shuttle mission STS-93.

  12. Thoughts on Teaching: And the Winner Is...

    ERIC Educational Resources Information Center

    Starnes, Bobby Ann

    2005-01-01

    What does it mean that Oscar-winner Hilary Swank's growing up in a trailer park is a big deal, that the author's son's education taught him his "broken home" puts him at risk, and that her niece used derogatory terms that could just as easily have been applied to her as to her enemy? The author thinks it says something about people's…

  13. James P. Allison received the 2014 Szent-Györgi Prize for Progress in Cancer Research

    PubMed Central

    Zhao, Jie; Scully, Peter; Ba, Sujuan

    2014-01-01

    The Szent-Györgyi Prize for Progress in Cancer Research is a prestigious scientific award established by the National Foundation for Cancer Research (NFCR)—a leading cancer research charitable organization in the United States that is committed to supporting innovative cancer research on the global scale that aims to cure cancer. Each year, the Szent-Györgyi Prize honors an outstanding researcher whose original discoveries have expanded our understanding of cancer and resulted in notable advances in cancer prevention, diagnosis, or treatment. The prize also promotes public awareness of the importance of basic cancer research and encourages the sustained investment needed to accelerate the translation of these research discoveries into new cancer treatments. This report highlights the history and mission of the Szent-Györgyi Prize, its role in promoting discovery-oriented cancer research, and the pioneering work led by the 2014 prize winner, Dr. James Allison. Dr. Allison's work in the area of cancer immunotherapy led to the successful development of immune checkpoint therapy, and the first drug approved by the United States Food and Drug Administration for the treatment of metastatic melanoma. PMID:25189714

  14. EDITORIAL: Roberts Prize for the best paper published in 2009 Roberts Prize for the best paper published in 2009

    NASA Astrophysics Data System (ADS)

    Webb, Steve; Harris, Simon

    2010-07-01

    The publishers of Physics in Medicine and Biology (PMB), IOP Publishing, in association with the journal owners, the Institute of Physics and Engineering in Medicine (IPEM), jointly award an annual prize for the best paper published in PMB during the previous year. The procedure for deciding the winner has been made as thorough as possible, to try to ensure that an outstanding paper wins the prize. We started off with a shortlist of the 10 research papers published in 2009 which were rated the best based on the referees' quality assessments. Following the submission of a short 'case for winning' document by each of the shortlisted authors, an IPEM college of jurors of the status of FIPEM assessed and rated these 10 papers in order to choose a winner, which was then endorsed by the Editorial Board. We have a clear, and very worthy, winner this year. We have much pleasure in advising readers that the 2009 Roberts Prize is awarded to E Z Zhang et al from University College London for their paper on photoacoustic tomography. In vivo high resolution 3D photoacoustic imaging of superficial vascular anatomy E Z Zhang, J G Laufer, R B Pedley and P C Beard 2009 Phys. Med. Biol. 54 1035-46 Our congratulations go to these authors. Of course all of the shortlisted papers were of great merit, and the full top-10 is listed below (in alphabetical order). Steve Webb Editor-in-Chief Simon Harris Publisher References Cheng Y-C N , Neelavalli J and Haacke E M 2009 Limitations of calculating field distributions and magnetic susceptibilities in MRI using a Fourier based method Phys. Med. Biol. 54 1169-89 Cho S, Ahn S, Li Q and Leahy R M 2009 Exact and approximate Fourier rebinning of PET data from time-of-flight to non time-of-flight 2009 Phys. Med. Biol. 54 467-84 Davidson S R H, Weersink R A, Haider M A, Gertner M R, Bogaards A, Giewercer D, Scherz A, Sherar M D, Elhilali M, Chin J L, Trachtenberg J and Wilson B C 2009 Treatment planning and dose analysis for interstitial

  15. Occupational Aspirations of State FFA Contest and Award Winners.

    ERIC Educational Resources Information Center

    Bowen, Blannie E.; Doerfert, David L.

    1989-01-01

    A study explored the occupational aspirations of 300 (of 503) students with high levels of participation in Future Farmers of America's (FFA) Computers in Agriculture (CIA), Proficiency Award (PA), and Prepared and Extemporaneous Speaking (PES) contests. CIA and PES winners aspired to professional occupations more than PA winners. PES winners…

  16. Meet the 2008 Cliff Weiss Memorial Essay Contest Winners

    ERIC Educational Resources Information Center

    Techniques: Connecting Education and Careers (J3), 2008

    2008-01-01

    This article presents the winners of the 2008 Cliff Weiss Memorial Essay Contest and their winning essays. The winners are Spencer Terry of Tulsa, Oklahoma (secondary), and Carrie Snyder-Renfro of Oklahoma City, Oklahoma (postsecondary). The topic for secondary students is "How would you communicate the impact and importance of CTE related to your…

  17. CIP's Eighth Annual Educational Software Contest: The Winners.

    ERIC Educational Resources Information Center

    Donnelly, Denis

    1997-01-01

    Announces the winners of an annual software contest for innovative software in physics education. Winning entries include an application to help students visualize the origin of energy bands in a solid, a package on the radioastronomy of pulsars, and a school-level science simulation program. Also includes student winners, honorable mentions,…

  18. Landau's Nobel Prize in Physics

    NASA Astrophysics Data System (ADS)

    Larsson, M.; Balatsky, A. V.

    2016-06-01

    Work of Lev Landau had a profound impact on the physics in 20th century. Landau had created the paradigms that had framed the conversations on the outstanding problems in physics for decades. He had laid foundations for our understanding of quantum matter like superfluidity, superconductivity and the theory of Fermi liquid. Here we present some Nobel Archive data on the winning nomination that led to the Nobel Prize in Physics in 1962.

  19. Next X-Prize: L1 Base with Linked Asteroid Mining as Prime Catalyst for Space Enterprise

    NASA Astrophysics Data System (ADS)

    Erickson, Ken R.

    2006-01-01

    We are at a cusp in our emergence as a space-faring race. Development of space resources offers unparalleled economic opportunities. Entrepreneurs with fortunes from the computer and internet revolutions are heavily investing in space. Their goal: to make space accessible to civilians at affordable prices, and build their next fortunes off-planet. The Ansari X-Prize showed that economic incentives can augment the pace and efficiency of this venture. Lunar and Martian missions are being touted as the top priorities by the US and other nations. However, serious and profitable expansion into space is best achieved by the establishment of an L1 base, its economic lifeblood based on processing asteroidal materials to provide the staples of all human space enterprise: oxygen, water, fuel and shielding. This paper outlines the components of an ``L1-prize'' modeled on the Ansari X-prize competition that led to the first private manned flight into space by Scaled Composites. The economic costs, crucial components and profit potential of a primary L1 base with asteroid mining technology intimately tied to it are detailed. The technical and economic benefits of the L1 location are contrasted to alternatives. The likely revenue sources are estimated, including contracting nations and industries; and orbital, lunar and Martian interplanetary enterprises. These are discussed as realistically and conservatively as possible in terms of the potential future profits for the winner of the prize.

  20. Frederick W. Alt received the 2015 Szent-Györgi Prize for Progress in Cancer Research.

    PubMed

    Scully, Peter; Zhao, Jie; Ba, Sujuan

    2016-02-03

    The Szent-Györgyi Prize for Progress in Cancer Research is a prestigious scientific award established by the National Foundation for Cancer Research (NFCR)--a leading cancer research charitable organization in the United States that is committed to supporting scientific research and public education relating to the prevention, early diagnosis, better treatments, and ultimately, a cure for cancer. Each year, the Szent-Györgyi Prize honors an outstanding researcher, nominated by colleagues or peers, who has contributed outstanding, significant research to the fight against cancer, and whose accomplishments have helped improve treatment options for cancer patients. The Prize also promotes public awareness of the importance of basic cancer research and encourages the sustained investment needed to accelerate the translation of these research discoveries into new cancer treatments. This report highlights the pioneering work led by the 2015 Prize winner, Dr. Frederick Alt. Dr. Alt's work in the area of cancer genetics over four decades has helped to shape the very roots of modern cancer research. His work continues to profoundly impact the approaches that doctors around the globe use to diagnose and treat cancer. In particular, his seminal discoveries of gene amplification and his pioneering work on molecular mechanisms of DNA damage repair have helped to usher in the era of genetically targeted therapy and personalized medicine.

  1. Positron-rubidium scattering

    NASA Technical Reports Server (NTRS)

    Mceachran, R. P.; Horbatsch, M.; Stauffer, A. D.

    1990-01-01

    A 5-state close-coupling calculation (5s-5p-4d-6s-6p) was carried out for positron-Rb scattering in the energy range 3.7 to 28.0 eV. In contrast to the results of similar close-coupling calculations for positron-Na and positron-K scattering the (effective) total integrated cross section has an energy dependence which is contrary to recent experimental measurements.

  2. Positron microprobe at LLNL

    SciTech Connect

    Asoka, P; Howell, R; Stoeffl, W

    1998-11-01

    The electron linac based positron source at Lawrence Livermore National Laboratory (LLNL) provides the world's highest current beam of keV positrons. We are building a positron microprobe that will produce a pulsed, focused positron beam for 3-dimensional scans of defect size and concentration with sub-micron resolution. The widely spaced and intense positron packets from the tungsten moderator at the end of the 100 MeV LLNL linac are captured and trapped in a magnetic bottle. The positrons are then released in 1 ns bunches at a 20 MHz repetition rate. With a three-stage re-moderation we will compress the cm-sized original beam to a 1 micro-meter diameter final spot on the target. The buncher will compress the arrival time of positrons on the target to less than 100 ps. A detector array with up to 60 BaF2 crystals in paired coincidence will measure the annihilation radiation with high efficiency and low background. The energy of the positrons can be varied from less than 1 keV up to 50 keV.

  3. Positrons in surface physics

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, Christoph

    2016-12-01

    Within the last decade powerful methods have been developed to study surfaces using bright low-energy positron beams. These novel analysis tools exploit the unique properties of positron interaction with surfaces, which comprise the absence of exchange interaction, repulsive crystal potential and positron trapping in delocalized surface states at low energies. By applying reflection high-energy positron diffraction (RHEPD) one can benefit from the phenomenon of total reflection below a critical angle that is not present in electron surface diffraction. Therefore, RHEPD allows the determination of the atom positions of (reconstructed) surfaces with outstanding accuracy. The main advantages of positron annihilation induced Auger-electron spectroscopy (PAES) are the missing secondary electron background in the energy region of Auger-transitions and its topmost layer sensitivity for elemental analysis. In order to enable the investigation of the electron polarization at surfaces low-energy spin-polarized positrons are used to probe the outermost electrons of the surface. Furthermore, in fundamental research the preparation of well defined surfaces tailored for the production of bound leptonic systems plays an outstanding role. In this report, it is envisaged to cover both the fundamental aspects of positron surface interaction and the present status of surface studies using modern positron beam techniques.

  4. 2016 Federal Green Challenge Award Winners in the Southeast Region

    EPA Pesticide Factsheets

    2016 FGC award winners in the Southeast are: the Department of Human Services’ U.S. Citizenship and Immigration Services Southeast Regional Office and Department of Energy’s East Tennessee Technology Park.

  5. 2016 Federal Green Challenge Award Winners in the Northeast Region

    EPA Pesticide Factsheets

    2016 Federal Green Challenge Award Winners in EPA's Region 2 (Northeast) are: Veterans Affairs Caribbean Healthcare Facility System (VACHS), Brookhaven National Laboratory, and General Services Administration (GSA) Region 2.

  6. Interview With the 2002 Caldecott Medal Winner, David Wiesner.

    ERIC Educational Resources Information Center

    Giorgis, Cyndi; Johnson, Nancy J.

    2003-01-01

    Discusses David Wiesner, the 2002 Caldecott Medal Winner, and includes excerpts of an interview with him. Notes that Wiesner's books appeal to the imagination and often use art elements such as scale. Details the winning book, "The Three Pigs." (PM)

  7. Who Should Pick the Winners of Climate Change?

    PubMed

    Webster, Michael S; Colton, Madhavi A; Darling, Emily S; Armstrong, Jonathan; Pinsky, Malin L; Knowlton, Nancy; Schindler, Daniel E

    2017-03-01

    Many conservation strategies identify a narrow subset of genotypes, species, or geographic locations that are predicted to be favored under different scenarios of future climate change. However, a focus on predicted winners, which might not prove to be correct, risks undervaluing the balance of biological diversity from which climate-change winners could otherwise emerge. Drawing on ecology, evolutionary biology, and portfolio theory, we propose a conservation approach designed to promote adaptation that is less dependent on uncertain predictions about the identity of winners and losers. By designing actions to facilitate numerous opportunities for selection across biological and environmental conditions, we can allow nature to pick the winners and increase the probability that ecosystems continue to provide services to humans and other species.

  8. Broad Prize: Do the Successes Spread?

    ERIC Educational Resources Information Center

    Samuels, Christina A.

    2011-01-01

    When the Broad Prize for Urban Education was created in 2002, billionaire philanthropist Eli Broad said he hoped the awards, in addition to rewarding high-performing school districts, would foster healthy competition; boost the prestige of urban education, long viewed as dysfunctional; and showcase best practices. Over the 10 years the prize has…

  9. Innovation Inducement Prizes: Connecting Research to Policy

    ERIC Educational Resources Information Center

    Besharov, Douglas J.; Williams, Heidi

    2012-01-01

    Innovation inducement prizes have been used for centuries. In the United States, a recent federal policy change--the America COMPETES Reauthorization Act of 2010--clarified and simplified a path by which all federal agencies can offer innovation inducement prizes, thus intensifying interest in how government agencies can most effectively design…

  10. Positrons for linear colliders

    SciTech Connect

    Ecklund, S.

    1987-11-01

    The requirements of a positron source for a linear collider are briefly reviewed, followed by methods of positron production and production of photons by electromagnetic cascade showers. Cross sections for the electromagnetic cascade shower processes of positron-electron pair production and Compton scattering are compared. A program used for Monte Carlo analysis of electromagnetic cascades is briefly discussed, and positron distributions obtained from several runs of the program are discussed. Photons from synchrotron radiation and from channeling are also mentioned briefly, as well as positron collection, transverse focusing techniques, and longitudinal capture. Computer ray tracing is then briefly discussed, followed by space-charge effects and thermal heating and stress due to showers. (LEW)

  11. EDITORIAL: Roberts Prize for the best paper published in 2010 Roberts Prize for the best paper published in 2010

    NASA Astrophysics Data System (ADS)

    Webb, Steve; Harris, Simon

    2011-08-01

    The publishers of Physics in Medicine and Biology (PMB), IOP Publishing, in association with the journal owners, the Institute of Physics and Engineering in Medicine (IPEM), jointly award an annual prize for the best paper published in PMB during the previous year. The procedure for deciding the winner has been made as thorough as possible, to try to ensure that an outstanding paper wins the prize. We started off with a shortlist of the 10 research papers published in 2010 which were rated the best based on the referees' quality assessments. Following the submission of a short 'case for winning' document by each of the shortlisted authors, an IPEM college of jurors of the status of FIPEM assessed and rated these 10 papers in order to choose a winner, which was then endorsed by the Editorial Board. We have much pleasure in advising readers that the Roberts Prize for the best paper published in 2010 is awarded to M M Paulides et al from Erasmus MC, Rotterdam, The Netherlands, for their paper on hyperthermia treatment: The clinical feasibility of deep hyperthermia treatment in the head and neck: new challenges for positioning and temperature measurement M M Paulides, J F Bakker, M Linthorst, J van der Zee, Z Rijnen, E Neufeld, P M T Pattynama, P P Jansen, P C Levendag and G C van Rhoon 2010 Phys. Med. Biol. 55 2465 Our congratulations go to these authors. Of course all of the shortlisted papers were of great merit, and the full top-10 is listed below (in alphabetical order). Steve Webb Editor-in-Chief Simon Harris Publisher References Alonzo-Proulx O, Packard N, Boone J M, Al-Mayah A, Brock K K, Shen S Z and Yaffe M J 2010 Validation of a method for measuring the volumetric breast density from digital mammograms Phys. Med. Biol. 55 3027 Bian J, Siewerdsen J H, Han X, Sidky E Y, Prince J L, Pelizzari C A and Pan X 2010 Evaluation of sparse-view reconstruction from flat-panel-detector cone-beam CT Phys. Med. Biol. 55 6575 Brun M-A, Formanek F, Yasuda A, Sekine M, Ando N

  12. Neocognitron trained with winner-kill-loser rule.

    PubMed

    Fukushima, Kunihiko

    2010-09-01

    The neocognitron, which was proposed by Fukushima (1980), is a hierarchical multi-layered neural network capable of robust visual pattern recognition. It acquires the ability to recognize patterns through learning. This paper proposes a new rule for competitive learning, named winner-kill-loser, and apply it to the neocognitron. The winner-kill-loser rule resembles the winner-take-all rule. Every time when a training stimulus is presented, non-silent cells compete with each other. The winner, however, not only takes all, but also kills losers. In other words, the winner learns the training stimulus, and losers are removed from the network. If all cells are silent, a new cell is generated and it learns the training stimulus. Thus feature-extracting cells gradually come to distribute uniformly in the feature space. The use of winner-kill-loser rule is not limited to the neocognitron. It is useful for various types of competitive learning, in general. This paper also proposes several improvements made on the neocognitron: such as, disinhibition to the inhibitory surround in the connections to C-cells (or complex cells) from S-cells (or simple cells); and square root shaped saturation in the input-to-output characteristics of C-cells. As a result of these improvements, the recognition rate of the neocognitron has been largely increased.

  13. 2014 WSEAT X-Prize

    SciTech Connect

    Bosiljevac, Thomas; Kramer, Sharlotte; Laing, John

    2014-10-01

    The 2014 WSEAT X-Prize is modeled as a double blind study to challenge the computational and material mechanics communities methodologies to develop better capabilities in modeling and experimentation to predict the failure in ductile metals. The challenge is presented as a distinct, yet relatively, simple geometry with all reported modeling predictions blind to each of the modeling teams. The experimental testing is validated by two independent test labs to confirm the experimentally observed behavior and results are unbiased and repeatable. The WSEAT X-Prize was issued to both external participants and internal participants as the Sandia Fracture Challenge 2 (SFC2) on May 30, 2014. A Challenge Supplemental Information Packet was sent to participants on August 13, 2014 to Prior years SFCs focused on the ability to predict failures under a quasi-static loading condition that focused on either a shear or tensile-dominated failure mode. This year’s challenge focuses on a geometry with a shear and/or tensile-dominated failure mode influenced by a moderate strain-rate ductile fracture in a metallic alloy.

  14. Positron diffusion in Si

    SciTech Connect

    Nielsen, B.; Lynn, K.G.; Vehanen, A.; Schultz, P.J.

    1985-06-01

    Positron diffusion in Si(100) and Si(111) has been studied using a variable energy positron beam. The positron diffusion coefficient is found to be D/sub +/ = 2.7 +- 0.3 cm/sup 2//sec using a Makhov-type positron implantation profile, which is demonstrated to fit the data more reliably than the more commonly applied exponential profile. The diffusion related parameter, E/sub 0/, which results from the exponential profile, is found to be 4.2 +- 0.2 keV, significantly longer than previously reported values. A drastic reduction in E/sub 0/ is found after annealing the sample at 1300 K, showing that previously reported low values of E/sub 0/ are probably associated with the thermal history of the sample.

  15. Sheeley Receives 2009 Hale Prize

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2009-05-01

    Neil Sheeley Jr., of the Space Science Division of the Naval Research Laboratory (NRL), has been awarded the 2009 George Ellery Hale Prize by the Solar Physics Division of the American Astronomical Society (AAS). The international award recognizes work in solar astronomy done over an extended period of time. Sheeley will receive the award in June at the AAS meeting in Pasadena, Calif. Sheeley is cited "for his continuing outstanding contributions to our understanding of the solar magnetic field, coronal holes, and coronal mass ejections. His wide-ranging observational and theoretical work has laid the foundation for much current research in solar and heliospheric physics, and continues to have important applications in space weather prediction."

  16. Science Underlying 2008 Nobel Prizes

    NASA Astrophysics Data System (ADS)

    Caldwell, Bernadette A.

    2009-01-01

    JCE offers a wealth of materials for teaching and learning chemistry that you can explore online. In the list below, Bernadette Caldwell of the Editorial Staff suggests additional resources that are available through JCE for teaching the science behind some of the 2008 Nobel Prizes . Discovering and Applying the Chemistry of GFP The Royal Swedish Academy of Sciences awarded the 2008 Nobel Prize in Chemistry for the discovery and development of the green fluorescent protein, GFP to three scientists: Osamu Shimomura, Martin Chalfie, and Roger Y. Tsien. These scientists led the field in discovering and introducing a fluorescing protein from jellyfish into cells and genes under study, which allows researchers to witness biochemistry in action. Now tags are available that emit light in different colors, revealing myriad biological processes and their interactions simultaneously. Identifying HPV and HIV, HIV's Replication Cycle, and HIV Virus-Host Interactions The Nobel Assembly at Karolinska Institutet awarded the 2008 Nobel Prize in Medicine or Physiology for their discovery of human immunodeficiency virus (HIV) to two scientists: Françoise Barré-Sinoussi and Luc Montagnier; and for his discovery of human papilloma viruses [HPV] causing cervical cancer to one scientist, Harald zur Hausen. Diseases caused by these infectious agents significantly affect global health. While isolating and studying the virus, researchers discovered HIV is an uncommon retrovirus that infects humans and relies on the host to make its viral DNA, infecting and killing the host's white blood cells, ultimately destroying the immune systems of infected humans. Related Resources at JCE Online The Journal has published articles relating to GFP specifically, and more generally to fluorescing compounds applied to biochemistry. The Journal has also published an article and a video on protease inhibition—a strategy to suppress HIV's biological processes. With the video clips, an accompanying guide

  17. 1998 federal energy and water management award winners

    SciTech Connect

    1998-10-28

    Energy is a luxury that no one can afford to waste, and many Federal Government agencies are becoming increasingly aware of the importance of using energy wisely. Thoughtful use of energy resources is important, not only to meet agency goals, but because energy efficiency helps improve air quality. Sound facility management offers huge savings that affect the agency`s bottom line, the environment, and workplace quality. In these fiscally-modest times, pursuing sound energy management programs can present additional challenges for energy and facility managers. The correct path to take is not always the easiest. Hard work, innovation, and vision are characteristic of those who pursue energy efficiency. That is why the Department of energy, Federal Energy Management Program (FEMP) is proud to salute the winners of the 1998 Federal Energy and Water Management Award. The 1998 winners represent the kind of 21st century thinking that will help achieve widespread Federal energy efficiency. In one year, the winners, through a combination of public and private partnerships, saved more than $222 million and 10.5 trillion Btu by actively identifying and implementing energy efficiency, water conservation, and renewable energy projects. Through their dedication, hard work, ingenuity, and success, the award winners have also inspired others to increase their own efforts to save energy and water and to more aggressively pursue the use of renewable energy sources. The Federal Energy and Water Management Awards recognize the winners` contributions and ability to inspire others to take action.

  18. Fishman Receives the Shaw Prize for Astronomy

    NASA Video Gallery

    In the video, Dr. Jerry Fishman discusses his career as a scientist, his lifelong interest in science and his recognition as the 2011 Shaw Prize Recipient for Astronomy. Fishman is being recognized...

  19. Nobel Prize 2014: Akasaki, Amano & Nakamura

    NASA Astrophysics Data System (ADS)

    Heber, Joerg

    2014-11-01

    The 2014 Nobel Prize in Physics has been awarded to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura "for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources."

  20. The matilda effect in science: awards and prizes in the US, 1990s and 2000s.

    PubMed

    Lincoln, Anne E; Pincus, Stephanie; Koster, Janet Bandows; Leboy, Phoebe S

    2012-04-01

    Science is stratified, with an unequal distribution of research facilities and rewards among scientists. Awards and prizes, which are critical for shaping scientific career trajectories, play a role in this stratification when they differentially enhance the status of scientists who already have large reputations: the 'Matthew Effect'. Contrary to the Mertonian norm of universalism--the expectation that the personal attributes of scientists do not affect evaluations of their scientific claims and contributions--in practice, a great deal of evidence suggests that the scientific efforts and achievements of women do not receive the same recognition as do those of men: the 'Matilda Effect'. Awards in science, technology, engineering and medical (STEM) fields are not immune to these biases. We outline the research on gender bias in evaluations of research and analyze data from 13 STEM disciplinary societies. While women's receipt of professional awards and prizes has increased in the past two decades, men continue to win a higher proportion of awards for scholarly research than expected based on their representation in the nomination pool. The results support the powerful twin influences of implicit bias and committee chairs as contributing factors. The analysis sheds light on the relationship of external social factors to women's science careers and helps to explain why women are severely underrepresented as winners of science awards. The ghettoization of women's accomplishments into a category of 'women-only' awards also is discussed.

  1. Templeton Prize again goes to physicist

    NASA Astrophysics Data System (ADS)

    Jeandron, Michelle

    2008-04-01

    The Polish mathematical physicist and former priest Michael Heller has been awarded this year's Templeton Prize. Heller, whose more than 40-year-long career has encompassed research in theology, philosophy, mathematics and cosmology, intends to use the £820 000 prize to found an interuniversity institute in Poland to investigate questions in science, theology and philosophy. Dubbed the "Copernicus Centre", the institute will be affiliated to the Jagiellonian University and the Pontifical Academy of Theology in Cracow.

  2. 'Winner-take-all' competition among real and illusory words.

    PubMed

    Niedeggen, Michael; Heil, Martin; Harris, Catherine L

    2006-04-03

    'Winner-take-all' networks are an important theoretical construct in visual neuroscience. An implication of winner-take-all networks is that a stimulus that wins the competition for selection receives maximal activation and will be consciously perceived, even when selection was incorrect. In this study, competition was induced between physically presented ('real') and self-constructed ('illusory') words. Semantic activation was probed by recording event-related potential responses to a downstream target word. The results showed that only words reported by participants triggered a spread of activation in the semantic system, whereas non-reported words failed to prime the target. Both effects were independent of whether the potential primes were 'real' or 'illusory'. Our findings indicate that neural 'winner-take-all' networks extend to the processing of lexical units.

  3. Alternative positron-target design for electron-positron colliders

    SciTech Connect

    Donahue, R.J. ); Nelson, W.R. )

    1991-04-01

    Current electron-positron linear colliders are limited in luminosity by the number of positrons which can be generated from targets presently used. This paper examines the possibility of using an alternate wire-target geometry for the production of positrons via an electron-induced electromagnetic cascade shower. 39 refs., 38 figs., 5 tabs.

  4. Nobel Prize for blue LEDs

    NASA Astrophysics Data System (ADS)

    Kraftmakher, Yaakov

    2015-05-01

    A brief review of lighting technologies is presented. Unavoidable restrictions for incandescent light bulbs caused by the Planck distribution and properties of the human eye are illustrated. The efficiency and luminous efficacy of thermal radiation are calculated for various temperatures; the results clearly show the limitations for thermal radiators. The only way to overcome these limitations is using non-thermal radiators, such as fluorescent lamps and light-emitting diodes (LEDs). Unique advantages of LEDs undoubtedly made a revolution in this field. A crucial element of this progress is the blue LEDs (Nobel Prize 2014). Some experiments with a blue and a green LED are described: (i) the luminescence triggered in a green-yellow phosphor inside a white LED by the blue LED; (ii) radiant spectra and ‘efficiency droop’ in the LEDs; (iii) modulation of the blue LED up to 4 MHz; and (iv) the h/e ratio from the turn-on voltage of the green LED. The experiments are suitable for undergraduate laboratories and usable as classroom demonstrations.

  5. Positron sources for Linear Colliders

    SciTech Connect

    Gai Wei; Liu Wanming

    2009-09-02

    Positron beams have many applications and there are many different concepts for positron sources. In this paper, only positron source techniques for linear colliders are covered. In order to achieve high luminosity, a linear collider positron source should have a high beam current, high beam energy, small emittance and, for some applications, a high degree of beam polarization. There are several different schemes presently being developed around the globe. Both the differences between these schemes and their common technical challenges are discussed.

  6. Superhydrophobic coating (2008 R&D 100 winner)

    ScienceCinema

    Jeff Brinker

    2016-07-12

    A transparent coating that is not just impermeable to water, but actually makes it bounce off a surface to help prevent corrosion, protect electronic and antiquities, or provide a new, more efficient surface to collect pure water. 2008 R&D 100 winner (SAND2008-2215W)

  7. 2000 Caldecott Medal Winner: A Conversation with Simms Taback.

    ERIC Educational Resources Information Center

    Giorgis, Cyndi; Johnson, Nancy J.

    2001-01-01

    Presents an interview with Simms Taback, winner of the 2000 Caldecott Award for his children's book illustrations. Discusses Taback's career as a graphic artist and children's book illustrator. Discusses intricate details and clever nuances in "Joseph Had a Little Overcoat," a warm and humorous tale proving that you can always make…

  8. Steven MacCall: Winner of LJ's 2010 Teaching Award

    ERIC Educational Resources Information Center

    Berry, John N., III

    2010-01-01

    This article profiles Steven L. MacCall, winner of "Library Journal's" 2010 Teaching Award. An associate professor at the School of Library and Information Studies (SLIS) at the University of Alabama, Tuscaloosa, MacCall was nominated by Kathie Popadin, known as "Kpop" to the members of her cohort in the online MLIS program at SLIS. Sixteen of…

  9. Global Power Play--Competition Winners Light Up the World

    ERIC Educational Resources Information Center

    Tech Directions, 2012

    2012-01-01

    This year's "Tech Directions" Inventors Competition asked students to come up with ways to provide electricity to remote villages that traditional electrical utilities have not yet reached. This article presents the results of the judging by inventor/electrical engineer Harry T. Roman. The winners are: (1) First Place--Scott Hulver,…

  10. An Interview with Toni Watt, 2004 Award Winner

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 2004

    2004-01-01

    Toni Austin Watt, the winner of the 2004 James Bryant Conant Award in High School Chemistry Teaching says that she was always an average student and had to invest more time in improving her skills and getting experiences, thus she is exhilarated that her efforts have received such acclaim and is honored that people thought her efforts were…

  11. Superhydrophobic coating (2008 R&D 100 winner)

    SciTech Connect

    Jeff Brinker

    2008-07-28

    A transparent coating that is not just impermeable to water, but actually makes it bounce off a surface to help prevent corrosion, protect electronic and antiquities, or provide a new, more efficient surface to collect pure water. 2008 R&D 100 winner (SAND2008-2215W)

  12. 2000 Newbery Medal Winner: A Conversation with Christopher Paul Curtis.

    ERIC Educational Resources Information Center

    Johnson, Nancy J.; Giorgis, Cyndi

    2001-01-01

    Presents an interview with 2000 Newbery Medal winner Christopher Paul Curtis. Reveals the author's journey as a reader and a writer, offers glimpses into the humor and upbeat attitude of Bud (the main character in Curtis' s award-winning book "Bud, Not Buddy"), and gives a peek into what readers can expect next from this award-winning…

  13. Roy Porter Student Essay Prize WinnerPsychiatry Limited: Hyperactivity and the Evolution of American Psychiatry, 1957–1980

    PubMed Central

    Smith, Matthew

    2008-01-01

    Summary Hyperactivity is the most commonly diagnosed childhood psychiatric disorder in north America. Most physicians believe that the disorder is a neurological dysfunction which is best treated with stimulants, such as ritalin. Accounts of the history of hyperactivity written by physicians, psychologists and even historians suggest that the disorder was always conceived as such. This paper argues that, on the contrary, the notion that hyperactivity was a neurological condition only emerged after vigorous debate during the 1960s between three competing fields within American psychiatry: specifically psychoanalysis, social psychiatry and biological psychiatry. Biological psychiatry won the debate, not because its approach to hyperactivity was more scientifically valid, but rather because its explanations and methods fit the prevailing social context more readily than that of its rivals. American psychiatry's refusal to draw pluralistic conclusions about hyperactivity undermined the development of a deeper understanding of the disorder. The history of hyperactivity provides an ideal lens through which to view the evolution of psychiatry from a field dominated by Freudian psychoanalysis to one rooted in the neurosciences.

  14. Positron annihilation processes update

    NASA Technical Reports Server (NTRS)

    Guessoum, Nidhal; Skibo, Jeffrey G.; Ramaty, Reuven

    1997-01-01

    The present knowledge concerning the positron annihilation processes is reviewed, with emphasis on the data of the cross sections of the various processes of interest in astrophysical applications. Recent results are presented including results on reaction rates and line widths, the validity of which is verified.

  15. Positron excitation of neon

    NASA Technical Reports Server (NTRS)

    Parcell, L. A.; Mceachran, R. P.; Stauffer, A. D.

    1990-01-01

    The differential and total cross section for the excitation of the 3s1P10 and 3p1P1 states of neon by positron impact were calculated using a distorted-wave approximation. The results agree well with experimental conclusions.

  16. The Japanese Positron Factory

    NASA Astrophysics Data System (ADS)

    Okada, S.; Sunaga, H.; Kaneko, H.; Takizawa, H.; Kawasuso, A.; Yotsumoto, K.; Tanaka, R.

    1999-06-01

    The Positron Factory has been planned at Japan Atomic Energy Research Institute (JAERI). The factory is expected to produce linac-based monoenergetic positron beams having world-highest intensities of more than 1010e+/sec, which will be applied for R&D of materials science, biotechnology and basic physics & chemistry. In this article, results of the design studies are demonstrated for the following essential components of the facilities: 1) Conceptual design of a high-power electron linac with 100 MeV in beam energy and 100 kW in averaged beam power, 2) Performance tests of the RF window in the high-power klystron and of the electron beam window, 3) Development of a self-driven rotating electron-to-positron converter and the performance tests, 4) Proposal of multi-channel beam generation system for monoenergetic positrons, with a series of moderator assemblies based on a newly developed Monte Carlo simulation and the demonstrative experiment, 5) Proposal of highly efficient moderator structures, 6) Conceptual design of a local shield to suppress the surrounding radiation and activation levels.

  17. High current pulsed positron microprobe

    SciTech Connect

    Howell, R.H.; Stoeffl, W.; Kumar, A.; Sterne, P.A.; Cowan, T.E.; Hartley, J.

    1997-05-01

    We are developing a low energy, microscopically focused, pulsed positron beam for defect analysis by positron lifetime spectroscopy to provide a new defect analysis capability at the 10{sup 10} e{sup +}s{sup -l} beam at the Lawrence Livermore National Laboratory electron linac. When completed, the pulsed positron microprobe will enable defect specific, 3-dimensional maps of defect concentrations with sub-micron resolution of defect location. By coupling these data with first principles calculations of defect specific positron lifetimes and positron implantation profiles we will both map the identity and concentration of defect distributions.

  18. Stephen Hawking bags big new 3m physics prize

    NASA Astrophysics Data System (ADS)

    Johnston, Hamish

    2013-01-01

    A massive 3m in prize money has gone to the British cosmologist Stephen Hawking for his work on black holes, quantum gravity and the early universe. The award is one of two "special fundamental physics prizes" from the Fundamental Physics Prize Foundation, which was set up earlier this year by the Russian physicist-turned-entrepreneur Yuri Milner.

  19. CMA Announces the 1996 Responsible Care Catalyst Awards Winners

    NASA Astrophysics Data System (ADS)

    1996-06-01

    Eighteen exceptional teachers of science, chemical technology, chemistry, and chemical engineering have been selected to receive a Responsible Care Chemical Manufacturers Association's 1996 Catalyst Award. The Responsible Care Catalyst Awards Program honors individuals who have the ability to inspire students toward careers in chemistry and science-related fields through their excellent teaching ability in and out of the classroom. The program also seeks to draw public attention to the importance of quality chemistry and science teaching at the undergraduate level. Since the award was established in 1957, 502 teachers of science, chemistry, and chemical engineering have been honored. Winners are selected from a wide range of nominations submitted by colleagues, friends, and administrators. All pre-high school, high school, two and four-year college, or university teachers in the United States and Canada are eligible. Each award winner will be presented with a medal and citation. National award winners receive 5,000; regional award winners receive 2,500. National Winners. Martin N. Ackermann, Oberlin College, Oberlin, OH Kenneth R. Jolls, Iowa State University, Ames, IA Suzanne Zobrist Kelly, Warren H. Meeker Elementary School, Ames, IA John V. Kenkel, Southeast Community College, Lincoln, NE George C. Lisensky, Beloit College, Beloit, WI James M. McBride, Yale University, New Haven, CT Marie C. Sherman, Ursuline Academy, St. Louis, MO Dwight D. Sieggreen, Cooke Middle School, Northville, MI Regional Winners Two-Year College. East-Georgianna Whipple-VanPatter, Central Community College, Hastings, NE West-David N. Barkan, Northwest College, Powell, WY High School. East-John Hnatow, Jr., Emmaus High School, Northampton, PA South-Carole Bennett, Gaither High School, Tampa, FL Midwest-Kenneth J. Spengler, Palatine High School, Palatine, IL West-Ruth Rand, Albuquerque, Albuquerque, NM Middle School. East-Thomas P. Kelly, Grandville Public Schools, Grandville, NH

  20. Generation of monoenergetic positrons

    SciTech Connect

    Hulett, L.D. Jr.; Dale, J.M.; Miller, P.D. Jr.; Moak, C.D.; Pendyala, S.; Triftshaeuser, W.; Howell, R.H.; Alvarez, R.A.

    1983-01-01

    Many experiments have been performed in the generation and application of monoenergetic positron beams using annealed tungsten moderators and fast sources of /sup 58/Co, /sup 22/Na, /sup 11/C, and LINAC bremstrahlung. This paper will compare the degrees of success from our various approaches. Moderators made from both single crystal and polycrystal tungsten have been tried. Efforts to grow thin films of tungsten to be used as transmission moderators and brightness enhancement devices are in progress.

  1. NVVC/NHJ Durrer prizes 2014.

    PubMed

    Wall, E E van der; Umans, V A W M

    2015-06-01

    At the annual 2015 Spring Congress of the NVVC, the Durrer prizes were awarded to the authors of two of the best original/review articles published in the year 2014, one paper being more basically oriented and one paper being more clinically oriented. This has been an annual tradition since the year 2006.

  2. NVVC/NHJ Durrer prizes 2013.

    PubMed

    van der Wall, E E; Umans, V A W M

    2014-05-01

    At the annual Spring Congress of the NVVC, the Durrer prizes were awarded to the authors of two of the best original/review articles published in the year 2013, one paper being more basically oriented and one paper being more clinically oriented. This annual tradition has existed since the year 2006.

  3. NVVC/NHJ Durrer Prizes 2012.

    PubMed

    van der Wall, E E; Schalij, M J; Umans, V A W M

    2013-06-01

    At the annual Spring Congress of the NVVC the Durrer prizes were awarded to the authors of the best original/review articles published in the year 2012, one paper being more basically-oriented and one paper being more clinically-oriented. This annual tradition exists already since the year 2006.

  4. NVVC/NHJ Durrer prizes 2015.

    PubMed

    van der Wall, E E

    2016-05-01

    At the annual 2016 Spring Congress of the NVVC, the Durrer prizes were awarded to the authors of two of the best original articles published in the year 2015, one paper being more basically oriented and one paper being more clinically oriented. This annual tradition has existed since the year 2006.

  5. Quantum pioneers snap up 2013 Wolf prize

    NASA Astrophysics Data System (ADS)

    Banks, Michael

    2013-02-01

    The 2013 Wolf Prize in Physics has been awarded to Juan Ignacio Cirac of the Max Planck Institute for Quantum Optics in Munich, Germany, and Peter Zoller of the University of Innsbruck in Austria for "groundbreaking theoretical contributions to quantum-information processing, quantum optics and the physics of quantum gases".

  6. How Einstein Got the Nobel Prize.

    ERIC Educational Resources Information Center

    Pais, Abraham

    1982-01-01

    Discusses why the Nobel Committee for Physics waited so long before giving Einstein the Nobel Prize and why they did not award it for relativity, but for the photoelectric effect instead. Focuses on the judgments of leading scientists who made nominations as well as committee members' decisions. (Author/JN)

  7. Pulse-firing winner-take-all networks

    NASA Technical Reports Server (NTRS)

    Meador, Jack L.

    1991-01-01

    Winner-take-all (WTA) neural networks using pulse-firing processing elements are introduced. In the pulse-firing WTA (PWTA) networks described, input and activation signal shunting is controlled by one shared lateral inhibition signal. This organization yields an O(n) area complexity that is convenient for integrated circuit implementation. Appropriately specified network parameters allow for the accurate continuous evaluation of inputs using a signal representation compatible with established pulse-firing neural network implementations.

  8. Spring Research Festival and NICBR Collaboration Winners Announced | Poster

    Cancer.gov

    By Carolynne Keenan, Contributing Writer, and Ashley DeVine, Staff Writer The winners of the 2014 Spring Research Festival (SRF), held May 7 and 8, were recognized on July 2, and included 20 NCI at Frederick researchers: Matthew Anderson, Victor Ayala, Matt Bess, Cristina Bergamaschi, Charlotte Choi, Rami Doueiri, Laura Guasch Pamies, Diana Haines, Saadia Iftikhar, Maria Kaltcheva, Wojciech Kasprzak, Balamurugan Kuppusamy, James Lautenberger, George Lountos, Megan Mounts, Uma Mudunuri, Martha Sklavos, Gloriana Shelton, Alex Sorum, and Shea Wright.

  9. Positron lifetime spectrometer using a DC positron beam

    DOEpatents

    Xu, Jun; Moxom, Jeremy

    2003-10-21

    An entrance grid is positioned in the incident beam path of a DC beam positron lifetime spectrometer. The electrical potential difference between the sample and the entrance grid provides simultaneous acceleration of both the primary positrons and the secondary electrons. The result is a reduction in the time spread induced by the energy distribution of the secondary electrons. In addition, the sample, sample holder, entrance grid, and entrance face of the multichannel plate electron detector assembly are made parallel to each other, and are arranged at a tilt angle to the axis of the positron beam to effectively separate the path of the secondary electrons from the path of the incident positrons.

  10. Positron moderation and detection for positronic atoms

    NASA Astrophysics Data System (ADS)

    Fardad, Abolfazl

    An apparatus is under development for H--+* production, atoms consisting of a positron bound in a Rydberg state to an H-- ion. High energy e+ from radioactive N2211a are slowed (moderated) to eV energies in solid neon and captured in a Penning trap. The procedure to deposit the neon is optimized, resulting in a 1.5% efficiency for moderating high energy e +. Neutral H--+* atoms with ˜100 eV will be produced from these trapped e+ and exit the trap, hitting a metal surface where the e+ annihilates. Back-to-back annihilation gamma photons (Egamma ≈ 0.511 MeV) detected in coincidence, at the expected energy are the fingerprint for H--+* production. A N2211a test source mocks H--+* experiments with ˜2.7% of the e+ emitting disintegrations detected. This high efficiency, with a background rate of ˜2.8 events/hour is achieved by surrounding the detectors with lead and cosmic ray detectors.

  11. Positron Annihilation in Insulating Materials

    SciTech Connect

    Asoka-Kumar, P; Sterne, PA

    2002-10-18

    We describe positron results from a wide range of insulating materials. We have completed positron experiments on a range of zeolite-y samples, KDP crystals, alkali halides and laser damaged SiO{sub 2}. Present theoretical understanding of positron behavior in insulators is incomplete and our combined theoretical and experimental approach is aimed at developing a predictive understanding of positrons and positronium annihilation characteristics in insulators. Results from alkali halides and alkaline-earth halides show that positrons annihilate with only the halide ions, with no apparent contribution from the alkali or alkaline-earth cations. This contradicts the results of our existing theory for metals, which predicts roughly equal annihilation contributions from cation and anion. We also present result obtained using Munich positron microprobe on laser damaged SiO{sub 2} samples.

  12. Bernard Lerer: Recipient of the 2014 Inaugural Werner Kalow Responsible Innovation Prize in Global Omics and Personalized Medicine (Pacific Rim Association for Clinical Pharmacogenetics)

    PubMed Central

    Aynacıoğlu, Şükrü; Bragazzi, Nicola Luigi; Dandara, Collet; Dove, Edward S.; Ferguson, Lynnette R.; Geraci, Christy Jo; Hafen, Ernst; Kesim, Belgin Eroğlu; Kolker, Eugene; Lee, Edmund J.D.; LLerena, Adrian; Nacak, Muradiye; Shimoda, Kazutaka; Someya, Toshiyuki; Srivastava, Sanjeeva; Tomlinson, Brian; Vayena, Effy; Warnich, Louise; Yaşar, Ümit

    2014-01-01

    Abstract This article announces the recipient of the 2014 inaugural Werner Kalow Responsible Innovation Prize in Global Omics and Personalized Medicine by the Pacific Rim Association for Clinical Pharmacogenetics (PRACP): Bernard Lerer, professor of psychiatry and director of the Biological Psychiatry Laboratory, Hadassah-Hebrew University Medical Center, Jerusalem, Israel. The Werner Kalow Responsible Innovation Prize is given to an exceptional interdisciplinary scholar who has made highly innovative and enduring contributions to global omics science and personalized medicine, with both vertical and horizontal (transdisciplinary) impacts. The prize is established in memory of a beloved colleague, mentor, and friend, the late Professor Werner Kalow, who cultivated the idea and practice of pharmacogenetics in modern therapeutics commencing in the 1950s. PRACP, the prize's sponsor, is one of the longest standing learned societies in the Asia-Pacific region, and was founded by Kalow and colleagues more than two decades ago in the then-emerging field of pharmacogenetics. In announcing this inaugural prize and its winner, we seek to highlight the works of prize winner, Professor Lerer. Additionally, we contextualize the significance of the prize by recalling the life and works of Professor Kalow and providing a brief socio-technical history of the rise of pharmacogenetics and personalized medicine as a veritable form of 21st century scientific practice. The article also fills a void in previous social science analyses of pharmacogenetics, by bringing to the fore the works of Kalow from 1995 to 2008, when he presciently noted the rise of yet another field of postgenomics inquiry—pharmacoepigenetics—that railed against genetic determinism and underscored the temporal and spatial plasticity of genetic components of drug response, with invention of the repeated drug administration (RDA) method that estimates the dynamic heritabilities of drug response. The prize goes a

  13. Positron Emission Tomography (PET)

    DOE R&D Accomplishments Database

    Welch, M. J.

    1990-01-01

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET.

  14. Quantum positron acoustic waves

    SciTech Connect

    Metref, Hassina; Tribeche, Mouloud

    2014-12-15

    Nonlinear quantum positron-acoustic (QPA) waves are investigated for the first time, within the theoretical framework of the quantum hydrodynamic model. In the small but finite amplitude limit, both deformed Korteweg-de Vries and generalized Korteweg-de Vries equations governing, respectively, the dynamics of QPA solitary waves and double-layers are derived. Moreover, a full finite amplitude analysis is undertaken, and a numerical integration of the obtained highly nonlinear equations is carried out. The results complement our previously published results on this problem.

  15. Positron Emission Tomography (PET)

    SciTech Connect

    Welch, M.J.

    1990-01-01

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET. 22 figs.

  16. EPA SBIR Recipient -- Winner of the 2013 Presidential Green Chemistry Challenge Awards

    EPA Pesticide Factsheets

    Faraday Technology, a 2011 Environmental Protection Agency Small Business Innovation Research (SBIR) recipient, was recently announced as a winner of the 2013 Presidential Green Chemistry Challenge Awards.

  17. Cyclotrons and positron emitting radiopharmaceuticals

    SciTech Connect

    Wolf, A.P.; Fowler, J.S.

    1984-01-01

    The state of the art of Positron Emission Tomography (PET) technology as related to cyclotron use and radiopharmaceutical production is reviewed. The paper discusses available small cyclotrons, the positron emitters which can be produced and the yields possible, target design, and radiopharmaceutical development and application. 97 refs., 12 tabs. (ACR)

  18. Portable Positron Measurement System (PPMS)

    SciTech Connect

    2011-01-01

    Portable Positron Measurement System (PPMS) is an automated, non-destructive inspection system based on positron annihilation, which characterizes a material's in situatomic-level properties during the manufacturing processes of formation, solidification, and heat treatment. Simultaneous manufacturing and quality monitoring now are possible. Learn more about the lab's project on our facebook site http://www.facebook.com/idahonationallaboratory.

  19. Portable Positron Measurement System (PPMS)

    ScienceCinema

    None

    2016-07-12

    Portable Positron Measurement System (PPMS) is an automated, non-destructive inspection system based on positron annihilation, which characterizes a material's in situatomic-level properties during the manufacturing processes of formation, solidification, and heat treatment. Simultaneous manufacturing and quality monitoring now are possible. Learn more about the lab's project on our facebook site http://www.facebook.com/idahonationallaboratory.

  20. Undulator Production of Polarized Positrons

    SciTech Connect

    William M. Bugg

    2008-08-27

    E-166 at SLAC has demonstrated the feasibilty of production of polarized positrons for the International Linear Collider using a helical undulator to produce polarized photons which are converted in a thin target to polarized positrons. The success of the experim ent has resulted in the choice of this technique for the baseline design of ILC.

  1. Prizes for innovation of new medicines and vaccines.

    PubMed

    Love, James; Hubbard, Tim

    2009-01-01

    This article argues that prizes can help stimulate medical innovation, control costs and ensure greater access to new medicines and vaccines. The authors explore four increasingly ambitious prize options to reward medical innovation, each addressing flaws in the current patent system. The first option promotes innovation through a large prize fund linked to the impact on health outcomes; the second option rewards the sharing of knowledge, data, and technology with open source dividends; the third option awards prizes for interim benchmarks and discrete technical problems; and the final option removes the exclusive right to use patented inventions in upstream research in favor of prizes. The authors conclude that a system of prizes to reward drug development would break the link between R&D incentives and product prices, and that such a reform is needed to improve innovation and access to new medicines and vaccines.

  2. The Brain Prize 2014: complex human functions.

    PubMed

    Grigaityte, Kristina; Iacoboni, Marco

    2014-11-01

    Giacomo Rizzolatti, Stanislas Dehaene, and Trevor Robbins were recently awarded the 2014 Grete Lundbeck European Brain Research Prize for their 'pioneering research on higher brain mechanisms underpinning such complex human functions as literacy, numeracy, motivated behavior and social cognition, and for their effort to understand cognitive and behavioral disorders'. Why was their work highlighted? Is there anything that links together these seemingly disparate lines of research?

  3. 2015 Nuclear Fusion Prize acceptance speech

    SciTech Connect

    Goldston, R. J.

    2016-12-19

    This is the 2015 Nuclear Fusion Prize acceptance speech of R.J. Goldston: It is a great pleasure to receive the 2015 Nuclear Fusion award for my work developing a heuristic drift-based model for the power scrape-off width in tokamaks. I was particularly pleased to receive the award from IAEA Director General Yukiya Amano, whose thoughtful leadership has advanced the cause of nuclear non-proliferation mightily.

  4. Profit Regulation of Defense and Prizes for Innovation

    DTIC Science & Technology

    1992-01-01

    AD-A253 965 Profit Regulation of Defense Contractors and Prizes for Innovation William P. Rogerson ,TIC ELECTE S AUG 191992 AD Ubi doewment bas bn...0004. ULbrary of Congress Cataloging in Publication Data Rogerson, William P. (William Paul), 1955- Profit regulation of defense contractors and prizes...Published 1992 by RAND 1700 Main Street, P.O. Box 2138, Santa Monica, CA 90407-2138 R-3635-PA&E Profit Regulation of Defense Contractors and Prizes for

  5. First AGU Climate Communication Prize awarded

    NASA Astrophysics Data System (ADS)

    McEntee, Christine

    2012-02-01

    Gavin Schmidt, a climate scientist at the NASA Goddard Institute for Space Studies and cofounder of the RealClimate blog (http://www.realclimate.org/), received the first AGU Climate Communication Prize at the honors ceremony. The prize recognizes excellence in climate communication as well as the promotion of scientific literacy, clarity of messaging, and efforts to foster respect and understanding for science-based values related to climate change. Sponsored by Nature's Own—a Boulder, Colo.-based company specializing in the sale of minerals, fossils, and decorative stone specimens—the prize comes with a $25,000 cash award. "AGU created this award to raise the visibility of climate change as a critical issue facing the world today, to demonstrate our support for scientists who commit themselves to the effective communication of climate change science, and to encourage more scientists to engage with the public and policy makers on how climate research can contribute to the sustainability of our planet," said AGU president Michael Mc Phaden. "That's why we are so pleased to recognize Gavin for his dedicated leadership and outstanding scientific achievements. We hope that his work will serve as an inspiration for others."

  6. Maria Goeppert Mayer and the Nobel Prize

    NASA Astrophysics Data System (ADS)

    Johnson, Karen E.

    2013-04-01

    When Maria Goeppert Mayer was awarded the Nobel Prize in Physics in 1963, she was only the second woman to receive that award and there have been no additional female physics laureates since. Mayer was uniquely prepared to carry out her prize-winning work on the nuclear shell model. Furthermore, she worked with some of the most well-known figures in mid-twentieth century physics, and her award came at a time when American science was in ascendance. Why, then, is her name so little known beyond the physics community? There are several possible answers to this question, ranging from the personal (her modest reaction to public acclaim) and the scientific (the mathematically abstract nature of her prize-winning work), to the national (the nature of the issues commanding public attention in the 1960s). In this talk I will present an overview of the circumstances that enabled Mayer to make exceptional contributions to nuclear physics, and then examine some of the possible reasons why her exceptional status is not more widely known.

  7. Positron emission mammography imaging

    SciTech Connect

    Moses, William W.

    2003-10-02

    This paper examines current trends in Positron Emission Mammography (PEM) instrumentation and the performance tradeoffs inherent in them. The most common geometry is a pair of parallel planes of detector modules. They subtend a larger solid angle around the breast than conventional PET cameras, and so have both higher efficiency and lower cost. Extensions to this geometry include encircling the breast, measuring the depth of interaction (DOI), and dual-modality imaging (PEM and x-ray mammography, as well as PEM and x-ray guided biopsy). The ultimate utility of PEM may not be decided by instrument performance, but by biological and medical factors, such as the patient to patient variation in radiotracer uptake or the as yet undetermined role of PEM in breast cancer diagnosis and treatment.

  8. 1984 Winners of the Cost Reduction Incentive Awards. NACUBO/USSF.

    ERIC Educational Resources Information Center

    National Association of College and University Business Officers, Washington, DC.

    Abstracts of college projects that were winners of the ninth annual Cost Reduction Incentive Awards Program are presented, including 47 programs that received monetary awards and 11 that received honorable mentions. One of the three top winners was Indiana University-Purdue University at Indianapolis, which used an ultrasound device to detect…

  9. School-to-Careers Company of the Year: 2000 Award Winners.

    ERIC Educational Resources Information Center

    National Employer Leadership Council, Washington, DC.

    This booklet profiles the four School-to-Careers Company of the Year Award winners judged to be demonstrating clearly the value and importance of these three key employer activities: working directly with students and teachers, building a school-to-careers system in the community, and strengthening company practice. The four winners and their…

  10. Mentoring, Self-Awareness, and Collaboration. The 2012 EDUCAUSE Award Winners

    ERIC Educational Resources Information Center

    Blythe, Earving L.; Swartz, David; Woo, Melissa

    2013-01-01

    The EDUCAUSE Awards Program, under the guidance of the EDUCAUSE Recognition Committee, has announced the three 2012 winners who are recognized for their peer endorsement and distinction to professional accomplishments in higher education information technology. Winner Melissa Woo is recognized as a strong leader and one who is expected to achieve…

  11. The Evolution of Creativity, Giftedness, and Multiple Intelligences: An Interview with Ellen Winner and Howard Gardner

    ERIC Educational Resources Information Center

    Henshon, Suzanna E.

    2006-01-01

    This article presents an interview with Ellen Winner and Howard Gardner. Winner is Professor of Psychology at Boston College, and Senior Research Associate at Project Zero, Harvard Graduate School of Education. Her research focuses on learning and cognition in the arts in typical and gifted children. She is the author of over 100 articles and…

  12. Numbers And Gains Of Neurons In Winner-Take-All Networks

    NASA Technical Reports Server (NTRS)

    Brown, Timothy X.

    1993-01-01

    Report presents theoretical study of gains required in neurons to implement winner-take-all electronic neural network of given size and related question of maximum size of winner-take-all network in which neurons have specified sigmoid transfer or response function with specified gain.

  13. Effect of reinforcement probability and prize size on cocaine and heroin abstinence in prize-based contingency management.

    PubMed

    Ghitza, Udi E; Epstein, David H; Schmittner, John; Vahabzadeh, Massoud; Lin, Jia-Ling; Preston, Kenzie L

    2008-01-01

    Although treatment outcome in prize-based contingency management has been shown to depend on reinforcement schedule, the optimal schedule is still unknown. Therefore, we conducted a retrospective analysis of data from a randomized clinical trial (Ghitza et al., 2007) to determine the effects of the probability of winning a prize (low vs. high) and the size of the prize won (small, large, or jumbo) on likelihood of abstinence until the next urine-collection day for heroin and cocaine users (N=116) in methadone maintenance. Higher probability of winning, but not the size of individual prizes, was associated with a greater percentage of cocaine-negative, but not opiate-negative, urines.

  14. EDITORIAL: Roberts Prize for the best paper published in 2011 Roberts Prize for the best paper published in 2011

    NASA Astrophysics Data System (ADS)

    Cherry, Simon; Ruffle, Jon

    2012-08-01

    The publishers of Physics in Medicine and Biology (PMB), IOP Publishing, in association with the journal owners, the Institute of Physics and Engineering in Medicine (IPEM), jointly award an annual prize for the best paper published in PMB during the previous year. The procedure for deciding the winner is a two-stage process. First, a shortlist of contenders is drawn up based on those papers that had the best referees' quality assessments, with a further quality check and endorsement by the Editorial Board. The papers on the shortlist are then reviewed by a specially convened IPEM committee consisting of members with fellow status. This committee reads the shortlisted papers and selects the winner. We have much pleasure in advising readers that the Roberts Prize for the best paper published in 2011 is awarded to Matthew Hough et al from the University of Florida, the Francis Marion University and the National Cancer Institute, USA for their paper on a comprehensive electron dosimetry model of skeletal tissues in the adult male: An image-based skeletal dosimetry model for the ICRP reference adult male—internal electron sources 2011 Phys. Med. Biol. 56 2309 Matthew Hough1, Perry Johnson1, Didier Rajon2, Derek Jokisch3, Choonsik Lee4 and Wesley Bolch1,5 1Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL, USA 2Department of Neurosurgery, University of Florida, Gainesville, FL, USA 3Department of Physics and Astronomy, Francis Marion University, Florence, SC, USA 4Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD, USA 5Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA Bone marrow is one of the more radiosensitive tissues in the human body and is housed within a complex structure of bone. This paper describes a comprehensive model of energy deposition by internal electron or beta particle emitters for the ICRP reference adult male based upon ex vivo CT and microCT images of

  15. EDITORIAL: Roberts Prize for the best paper published in 2012 Roberts Prize for the best paper published in 2012

    NASA Astrophysics Data System (ADS)

    Cherry, Simon; Ruffle, Jon

    2013-08-01

    The publishers of Physics in Medicine and Biology (PMB), IOP Publishing, in association with the journal owners, the Institute of Physics and Engineering in Medicine (IPEM), jointly award the Roberts prize for the best paper published in PMB during the previous year. The procedure for deciding the winner is a two-stage process. First, a shortlist of contenders is drawn up based on those papers that had the best referees' quality assessments, with a further quality check and endorsement by the Editorial Board. The papers on the shortlist are then reviewed by a specially convened IPEM committee consisting of members with fellow status. This committee reads the shortlisted papers and selects the winner. We have much pleasure in advising readers that the Roberts Prize for the best paper published in 2012 is awarded to Michel Defrise, Ahmadreza Rezaei and Johan Nuyts from the Vrije Universiteit Brussels and the Katholieke Universiteit Leuven, Belgium for their breakthrough paper that describes how the information needed for attenuation correction in PET imaging can be extracted, to within a constant, from time-of-flight emission data: Time-of-flight PET data determine the attenuation sinogram up to a constant 2012 Phys. Med. Biol. 57 885 Michel Defrise1, Ahmadreza Rezaei2 and Johan Nuyts2 1Department of Nuclear Medicine, Vrije Universiteit Brussel, B-1090 Brussels, Belgium 2Department of Nuclear Medicine, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium This paper represents an important and timely contribution to the literature as time-of-flight PET scanners are now offered by several manufacturers. In hybrid PET/CT scanners, the PET attenuation correction, necessary for quantitative reconstruction of the tracer distribution, can be derived directly from the CT data. Sometimes, however, the PET and CT scans may be poorly aligned due to patient motion and other approaches are needed. In addition, hybrid PET/MRI scanners also, have been developed recently, and in

  16. Intense source of slow positrons

    NASA Astrophysics Data System (ADS)

    Perez, P.; Rosowsky, A.

    2004-10-01

    We describe a novel design for an intense source of slow positrons based on pair production with a beam of electrons from a 10 MeV accelerator hitting a thin target at a low incidence angle. The positrons are collected with a set of coils adapted to the large production angle. The collection system is designed to inject the positrons into a Greaves-Surko trap (Phys. Rev. A 46 (1992) 5696). Such a source could be the basis for a series of experiments in fundamental and applied research and would also be a prototype source for industrial applications, which concern the field of defect characterization in the nanometer scale.

  17. Cosmic Ray Positrons from Pulsars

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2010-01-01

    Pulsars are potential Galactic sources of positrons through pair cascades in their magnetospheres. There are, however, many uncertainties in establishing their contribution to the local primary positron flux. Among these are the local density of pulsars, the cascade pair multiplicities that determine the injection rate of positrons from the pulsar, the acceleration of the injected particles by the pulsar wind termination shock, their rate of escape from the pulsar wind nebula, and their propagation through the interstellar medium. I will discuss these issues in the context of what we are learning from the new Fermi pulsar detections and discoveries.

  18. Positron annihilation spectroscopy with magnetically analyzed beams

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Holt, W. H.; Mock, W., Jr.

    1982-01-01

    Lifetime measurements with magnetically analyzed positron beams were made in condensed media with uniform and non-uniform properties. As expected, the lifetime values with magnetically analyzed positron beams in uniform targets are similar to those obtained with conventional positron sources. The lifetime values with magnetically analyzed beams in targets which have non-uniform properties vary with positron energy and are different from the conventional positron source derived lifetime values in these targets.

  19. Nominations sought for the 2016 Haagen-Smit Prize

    NASA Astrophysics Data System (ADS)

    2016-09-01

    We, the editors and publishers of Atmospheric Environment invite our readers to nominate papers for the 2016 "Haagen-Smit Prize". The prize is named in honor of Prof. Arie Jan Haagen-Smit, a pioneer in the field of air pollution.

  20. 29 CFR 778.330 - Prizes or contest awards generally.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Prizes or contest awards generally. 778.330 Section 778.330 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS OVERTIME COMPENSATION Special Problems Prizes As Bonuses § 778.330...

  1. 26 CFR 1.74-1 - Prizes and awards.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Prizes and awards. 1.74-1 Section 1.74-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Included in Gross Income § 1.74-1 Prizes and awards. (a) Inclusion in gross income. (1) Section...

  2. Nobel physics prize to Charpak for inventing particle detectors

    SciTech Connect

    Schwarzschild, B.

    1993-01-01

    This article describes the work of Georges Charpak of France leading to his receipt of the 1992 Nobel Prize in Physics. The Nobel Prize was awarded to Charpak [open quotes]for his invention and development of particle detectors, in particular the multiwire proportional chamber.[close quotes] Historical aspects of Charpak's life and research are given.

  3. Resolvability of positron decay channels

    SciTech Connect

    Fluss, M.J.; Howell, R.H.; Rosenberg, I.J.; Meyer, P.

    1985-03-07

    Many data analysis treatments of positron experiments attempt to resolve two or more positron decay or exist channels which may be open simultaneously. Examples of the need to employ such treatments of the experimental results can be found in the resolution of the constituents of a defect ensemble, or in the analysis of the complex spectra which arise from the interaction of slow positrons at or near the surfaces of solids. Experimental one- and two-dimensional angular correlation of annihilation radiation experiments in Al single crystals have shown that two defect species (mono- and divacancies) can be resolved under suitable conditions. Recent experiments at LLNL indicate that there are a variety of complex exit channels open to positrons interacting at surfaces, and ultimely these decay channels must also be suitably resolved from one another. 6 refs., 4 figs.

  4. Positron trapping at grain boundaries

    SciTech Connect

    Dupasquier, A. ); Romero, R.; Somoza, A. )

    1993-10-01

    The standard positron trapping model has often been applied, as a simple approximation, to the interpretation of positron lifetime spectra in situations of diffusion-controlled trapping. This paper shows that this approximation is not sufficiently accurate, and presents a model based on the correct solution of the diffusion equation, in the version appropriate for studying positron trapping at grain boundaries. The model is used for the analysis of new experimental data on positron lifetime spectra in a fine-grained Al-Ca-Zn alloy. Previous results on similar systems are also discussed and reinterpreted. The analysis yields effective diffusion coefficients not far from the values known for the base metals of the alloys.

  5. High Power Polarized Positron Source

    NASA Astrophysics Data System (ADS)

    Mikhailichenko, Alexander

    2009-09-01

    We discuss the basics of polarized positron production by low energy polarized electrons. Efficiency of conversion ˜0.1-1% might be interesting for the Continuous Electron Beam Accelerator Facility (CEBAF) and the International Linear Collider (ILC).

  6. Photon correlations in positron annihilation

    SciTech Connect

    Gauthier, Isabelle; Hawton, Margaret

    2010-06-15

    The two-photon positron annihilation density matrix is found to separate into a diagonal center-of-energy factor implying maximally entangled momenta, and a relative factor describing decay. For unknown positron injection time, the distribution of the difference in photon arrival times is a double exponential at the para-Ps decay rate, consistent with experiment [V. D. Irby, Meas. Sci. Technol. 15, 1799 (2004)].

  7. Modelling Positron Interactions with Matter

    NASA Astrophysics Data System (ADS)

    Garcia, G.; Petrovic, Z.; White, R.; Buckman, S.

    2011-05-01

    In this work we link fundamental measurements of positron interactions with biomolecules, with the development of computer codes for positron transport and track structure calculations. We model positron transport in a medium from a knowledge of the fundamental scattering cross section for the atoms and molecules comprising the medium, combined with a transport analysis based on statistical mechanics and Monte-Carlo techniques. The accurate knowledge of the scattering is most important at low energies, a few tens of electron volts or less. The ultimate goal of this work is to do this in soft condensed matter, with a view to ultimately developing a dosimetry model for Positron Emission Tomography (PET). The high-energy positrons first emitted by a radionuclide in PET may well be described by standard formulas for energy loss of charged particles in matter, but it is incorrect to extrapolate these formulas to low energies. Likewise, using electron cross-sections to model positron transport at these low energies has been shown to be in serious error due to the effects of positronium formation. Work was supported by the Australian Research Council, the Serbian Government, and the Ministerio de Ciencia e Innovación, Spain.

  8. Effect of Reinforcement Probability and Prize Size on Cocaine and Heroin Abstinence in Prize-Based Contingency Management

    ERIC Educational Resources Information Center

    Ghitza, Udi E.; Epstein, David H.; Schmittner, John; Vahabzadeh, Massoud; Lin, Jia-Ling; Preston, Kenzie L.

    2008-01-01

    Although treatment outcome in prize-based contingency management has been shown to depend on reinforcement schedule, the optimal schedule is still unknown. Therefore, we conducted a retrospective analysis of data from a randomized clinical trial (Ghitza et al., 2007) to determine the effects of the probability of winning a prize (low vs. high) and…

  9. Characterizing and modelling persistence in the number of lottery winners

    NASA Astrophysics Data System (ADS)

    Antonio, Fernando J.; Mendes, Renio S.; Itami, Andreia S.; Picoli, Sergio

    2015-06-01

    Lottery is the most famous branch among all the games of chance. By analysing data from Mega-Sena, the major lottery in Brazil, we investigated the presence of persistent behaviour in the time series of the number of winners. We found that the demand for tickets grew collectively as an exponential driven by the size of the accumulated jackpot. Finally, we identified that a stochastic model grounded on the rolling-over feature of lotteries can generate correlations qualitatively similar to those observed empirically. The model is consistent with the idea that the growth in the number of bets, motivated by the size of the expected jackpot, is a mechanism generator of correlations in an apparently random scenario.

  10. Weak winner effect in a less aggressive mammal: correlations with corticosterone but not testosterone.

    PubMed

    Oyegbile, Temitayo O; Marler, Catherine A

    2006-09-30

    We investigated the existence of the "winner effect" (winning an aggressive encounter following previous victories) and an associated rise in testosterone (T) in the white-footed mouse (Peromyscus leucopus) which generally display low levels of aggression and territoriality. We compared the effect of previously winning three, two, one, or zero resident-intruder encounters on the likelihood of winning a subsequent aggressive encounter. Although 50% of males were removed during training because of peaceful encounters, the winner effect was weak and not significant. We hypothesize that territoriality/aggression may be associated with the strength of the winner effect and discuss whether the slight winner effect exhibited by P. leucopus may become significant when population densities increase and males become more territorial. There was also no associated change in T with winning; however, corticosterone (Cort) changed with experience as winners had low Cort levels compared to losers and controls. Furthermore, low Cort levels in winners were associated with quicker attack latencies. These results contrast with findings of a significant winner effect and increase in T in males of the highly territorial and aggressive California mouse (Peromyscus californicus) using an identical methodology. California mice also attacked their opponents at more caudal regions of the body compared to white-footed mice that attacked their opponents at more rostral regions of the body, possibly related to different levels/types of aggression expressed by the two species.

  11. Society News: Welcome to Griffiths Bay; RAS Associate wins Shaw Prize; Postgraduate prize preparations; Council minutes on-line; Birthday Honours; Kavli Prize; New Fellows

    NASA Astrophysics Data System (ADS)

    2008-08-01

    The late Donald Griffiths will be commemorated in the name of a bay on the Antarctic Peninsula. Prof. Reinhard Genzel, Associate of the Society since 1994, Darwin Lecturer in 2007, and Director of the Max Planck Institute for Extraterrestrial Physics has been awarded the Shaw Prize in Astronomy for 2008. While postgrad students complete their PhD theses, supervisors should note the deadline for submissions to the annual Michael Penston and Keith Runcorn Prizes.

  12. Method for photon activation positron annihilation analysis

    DOEpatents

    Akers, Douglas W.

    2006-06-06

    A non-destructive testing method comprises providing a specimen having at least one positron emitter therein; determining a threshold energy for activating the positron emitter; and determining whether a half-life of the positron emitter is less than a selected half-life. If the half-life of the positron emitter is greater than or equal to the selected half-life, then activating the positron emitter by bombarding the specimen with photons having energies greater than the threshold energy and detecting gamma rays produced by annihilation of positrons in the specimen. If the half-life of the positron emitter is less then the selected half-life, then alternately activating the positron emitter by bombarding the specimen with photons having energies greater then the threshold energy and detecting gamma rays produced by positron annihilation within the specimen.

  13. PREFACE 12th International Workshop on Slow Positron Beam Techniques

    NASA Astrophysics Data System (ADS)

    Buckman, Stephen; Sullivan, James; White, Ronald

    2011-01-01

    Preface These proceedings arose from the 12th International Workshop on Slow Positron Beam Techniques (SLOPOS12), which was held on Magnetic Island, North Queensland, Australia, between 1-6th August 2010. Meetings in the SLOPOS series are held (roughly) every three years and have now been held on (almost) all continents, indicating the truly international nature of the field. SLOPOS12 marked the second time that the Workshop had been held in the southern hemisphere, and the first time in Australia. SLOPOS12 attracted 122 delegates from 16 countries. Most encouraging was the attendance of 28 student delegates, and that about half of the overall delegates were early career researchers - a good sign for the future of our field. We also enjoyed the company of more than a dozen partners and families of delegates. In a slight departure from previous SLOPOS meetings, the International Advisory Committee approved a broader scope of scientific topics for inclusion in the program for the 2010 Workshop. This broader scope was intended to capture the applications of positrons in atomic, molecular and biomedical areas and was encapsulated in the byeline for SLOPOS-12: The 12th International Workshop on Slow Positron Beam Techniques for Solids, Surfaces, Atoms and Molecules. The scientific and social program for the meeting ran over 6 days with delegates gathering on Sunday August 1st and departing on August 6th. The scientific program included plenary, invited, contributed and student lectures, the latter being the subject of a student prize. In all there were 53 oral presentations during the week. There were also two poster sessions, with 63 posters exhibited, and a prize was awarded for the best poster by a student delegate. The standard of the student presentations, both oral and posters, was outstanding, so much so that the judging panel recommended an additional number of prizes be awarded. Topics that were the focus of invited presentations and contributed papers at

  14. Prize level and debt size: impact on gambling behaviour.

    PubMed

    Crewe-Brown, Courtney; Blaszczynski, Alex; Russell, Alex

    2014-09-01

    No studies to date have specifically determined the relationship between prize levels, debt size, and impulsivity on reported gambling behaviour on Electronic Gaming Machines (EGM). The present study reports the findings of a pilot study designed to investigate whether or not the likelihood of increasing the size of a bet was related to the level of prize offered and personal debt. The sample consisted of 171 first year psychology students (61 males and 120 females). Participants completed a series of gambling vignettes designed to elicit data on reported bet size according to different prize levels and debt sizes; the Eysenck Impulsivity Scale (Eysenck and Eysenck 1977); the Canadian Problem Gambling Index; and an author-constructed questionnaire eliciting data on demographic and gambling behaviours. Results indicated that as prize levels increase the odds (relative risk) of an individual placing a bet on an EGM and the amount of money reportedly bet tends to increase. A negative relationship between debt size and reported gambling behaviour moderated by prize level was found. No differences were found in the odds of placing a bet according to impulsivity. It was concluded that prize and debt sizes do influence propensities to gamble and level of bets. The findings have implications for restricting jackpot and general prize levels as a responsible gambling strategy designed to reduce motivations to gamble.

  15. The Road to Stockholm - Nobel Prizes, Science, and Scientists

    NASA Astrophysics Data System (ADS)

    Hargittai, István

    2002-05-01

    The Nobel Prize is by far the highest recognition a scientist may receive and the only one with which the general public is familiar. Its prestige has reached improbable heights. At the same time a lot of myth surrounds the Nobel Prize, and this is compounded by the fact that people tend to view scientists with some bewilderment.This book introduces the process of selection of the laureates, discusses the ingredients for scientific discovery and for getting recognition. It reviews the decisive moments of scientific careers en route to the Nobel Prize, points to characteristic features of the laureates, the importance of mentors and venues in scientific careers and other components of success. It also covers some discoverers and discoveries for whom and for which the Nobel Prize never materialized.Whereas there is no general recipe for receiving the Nobel Prize, there are common features of successful scientific careers. The book reveals some information about the scientists' lives and careers that may guide other scientists in increasing their chances of becoming more effective and better recognized players--although it is not expected to help anyone to receive the Nobel Prize!For the general reader The Road to Stockholm reveals the human face of scientists and the human side of their endeavours. The Nobel Prize has served as inspiration for scientists and the general public for a hundred years: this book discusses its problems and celebrates its triumphs.

  16. Positron spectroscopy for materials characterization

    SciTech Connect

    Schultz, P.J.; Snead, C.L. Jr.

    1988-01-01

    One of the more active areas of research on materials involves the observation and characterization of defects. The discovery of positron localization in vacancy-type defects in solids in the 1960's initiated a vast number of experimental and theoretical investigations which continue to this day. Traditional positron annihilation spectroscopic techniques, including lifetime studies, angular correlation, and Doppler broadening of annihilation radiation, are still being applied to new problems in the bulk properties of simple metals and their alloys. In addition new techniques based on tunable sources of monoenergetic positron beams have, in the last 5 years, expanded the horizons to studies of surfaces, thin films, and interfaces. In the present paper we briefly review these experimental techniques, illustrating with some of the important accomplishments of the field. 40 refs., 19 figs.

  17. Positron emitter labeled enzyme inhibitors

    DOEpatents

    Fowler, Joanna S.; MacGregor, Robert R.; Wolf, Alfred P.; Langstrom, Bengt

    1990-01-01

    This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

  18. Positron emitter labeled enzyme inhibitors

    SciTech Connect

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.; Langstrom, B.

    1990-04-03

    This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

  19. Positron emitter labeled enzyme inhibitors

    DOEpatents

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.

    1987-05-22

    This invention involved a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide in activators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography. 2 figs.

  20. Positron-alkali atom scattering

    NASA Technical Reports Server (NTRS)

    Mceachran, R. P.; Horbatsch, M.; Stauffer, A. D.; Ward, S. J.

    1990-01-01

    Positron-alkali atom scattering was recently investigated both theoretically and experimentally in the energy range from a few eV up to 100 eV. On the theoretical side calculations of the integrated elastic and excitation cross sections as well as total cross sections for Li, Na and K were based upon either the close-coupling method or the modified Glauber approximation. These theoretical results are in good agreement with experimental measurements of the total cross section for both Na and K. Resonance structures were also found in the L = 0, 1 and 2 partial waves for positron scattering from the alkalis. The structure of these resonances appears to be quite complex and, as expected, they occur in conjunction with the atomic excitation thresholds. Currently both theoretical and experimental work is in progress on positron-Rb scattering in the same energy range.

  1. Best Practices of Multiple-Time SmartWay Award Winners

    EPA Pesticide Factsheets

    This EPA presentations focus is on the SmartWay Excellence Awards multiple winners, their best practices in protecting the environment, incorporating sustainability and reducing carbon pollution, along with benefits of being a partner.

  2. OHIO INTERNATIONAL TELEVISION AND VIDEO FESTIVAL AWARD WINNERS FROM THE IMAGING TECHNOLOGY CENTER IT

    NASA Technical Reports Server (NTRS)

    2000-01-01

    OHIO INTERNATIONAL TELEVISION AND VIDEO FESTIVAL AWARD WINNERS FROM THE IMAGING TECHNOLOGY CENTER ITC KEVIN BURKE - BILL FLETCHER - GARY NOLAN - EMERY ADANICH FOR THE VIDEO ENTITLED ICING FOR REGIONAL AND CORPORATE PILOTS

  3. Positron program at the Idaho Accelerator Center

    SciTech Connect

    Stancari, Giulio

    2009-09-02

    Positron physics is an important part of the research activities at the Idaho Accelerator Center (IAC). With positron annihilation spectroscopy, maps of nanodefects in materials have been obtained. For this purpose, positrons are generated by radioactive decay, photoactivation, or pair production. Preliminary tests of positron sources in the MeV range based on electron linacs have also been carried out at the IAC, and an expansion of this program is planned. A similar positron beam at Jefferson Lab would greatly improve our knowledge of the inner structure of the proton. In this paper, research with positrons at the IAC is reviewed. After a description of the Center's facilities, results from positron annihilation spectroscopy are discussed, together with future plans for testing a prototype positron source for CEBAF.

  4. Particle physics. Positrons ride the wave

    SciTech Connect

    Piot, Philippe

    2015-08-26

    Here, experiments reveal that positrons — the antimatter equivalents of electrons — can be rapidly accelerated using a plasma wave. The findings pave the way to high-energy electron–positron particle colliders.

  5. Bites and B-Roll: Announcments of the Architecture Contest Winners

    SciTech Connect

    2009-10-14

    Broadcast-quality downloads of this video are available free and unrestricted at http://stratacomm.net/solar-decathlon... Video contains announcements of the architecture awards announcement at the 2009 Solar Decathlon. Includes announcement and house b-roll of 1st place winner Team California and 2nd place winner Rice University's houses, general Solar Village b-roll, and bites from students and architecture experts

  6. Bites and B-Roll: Announcments of the Architecture Contest Winners

    ScienceCinema

    None

    2016-07-12

    Broadcast-quality downloads of this video are available free and unrestricted at http://stratacomm.net/solar-decathlon... Video contains announcements of the architecture awards announcement at the 2009 Solar Decathlon. Includes announcement and house b-roll of 1st place winner Team California and 2nd place winner Rice University's houses, general Solar Village b-roll, and bites from students and architecture experts

  7. Neuronal networks with NMDARs and lateral inhibition implement winner-takes-all

    PubMed Central

    Shoemaker, Patrick A.

    2015-01-01

    A neural circuit that relies on the electrical properties of NMDA synaptic receptors is shown by numerical and theoretical analysis to be capable of realizing the winner-takes-all function, a powerful computational primitive that is often attributed to biological nervous systems. This biophysically-plausible model employs global lateral inhibition in a simple feedback arrangement. As its inputs increase, high-gain and then bi- or multi-stable equilibrium states may be assumed in which there is significant depolarization of a single neuron and hyperpolarization or very weak depolarization of other neurons in the network. The state of the winning neuron conveys analog information about its input. The winner-takes-all characteristic depends on the nonmonotonic current-voltage relation of NMDA receptor ion channels, as well as neural thresholding, and the gain and nature of the inhibitory feedback. Dynamical regimes vary with input strength. Fixed points may become unstable as the network enters a winner-takes-all regime, which can lead to entrained oscillations. Under some conditions, oscillatory behavior can be interpreted as winner-takes-all in nature. Stable winner-takes-all behavior is typically recovered as inputs increase further, but with still larger inputs, the winner-takes-all characteristic is ultimately lost. Network stability may be enhanced by biologically plausible mechanisms. PMID:25741276

  8. Coalition formation in animals and the nature of winner and loser effects.

    PubMed Central

    Johnstone, R A; Dugatkin, L A

    2000-01-01

    Coalition formation has been documented in a diverse array of taxa, yet there has been little formal analysis of polyadic interactions such as coalitions. Here, we develop an optimality model which examines the role of winner and loser effects in shaping coalition formation. We demonstrate that the predicted patterns of alliances are strongly dependent on the way in which winner and loser effects change with contestant strength. When winner and loser effects decrease with the resource-holding power (RHP) of the combatants, coalitions will be favoured between the strongest members of a group, but not between the weakest. If, in contrast, winner and loser effects increase with RHP, exactly the opposite predictions emerge. All other things being equal, intervention is more likely to prove worthwhile when the beneficiary of the aid is weaker (and its opponent is stronger), because the beneficiary is then less likely to win without help. Consequently, intervention is more probable when the impact of victory on the subsequent performance of a combatant increases with that individual's strength because this selects for intervention in favour of weaker combatants. The published literature on hierarchy formation does not reveal how winner and loser effects actually change with contestant strength and we therefore hope that our model will spur others to collect such data; in this light we suggest an experiment which will help to elucidate the nature of winner and loser effects and their impact on coalition formation in animals. PMID:10670947

  9. Species differences in the winner effect disappear in response to post-victory testosterone manipulations.

    PubMed

    Fuxjager, Matthew J; Montgomery, Jon L; Marler, Catherine A

    2011-12-07

    Evolutionary processes can interact with the mechanisms of steroid hormone action to drive interspecific variation in behavioural output, yet the exact nature of these interactions is poorly understood. To investigate this issue, we compare the endocrine machinery underlying the winner effect (an ability to increase winning behaviour in response to past victories) in two closely related species of Peromyscus mice. Typically, after winning a fight, California mice (Peromyscus californicus) experience a testosterone (T) surge that helps enhance their future winning behaviour, whereas white-footed mice (Peromyscus leucopus) experience neither a T surge nor a change in subsequent winning behaviour. However, our results indicate that when the post-victory T response of male white-footed mice is phenotypically engineered to resemble that of California mice, individuals are capable of developing a strong and lasting winner effect. Moreover, this 'induced' winner effect in white-footed mice qualitatively matches the winner effect that develops naturally in California mice. Taken together, these findings suggest that white-footed mice have the physiological machinery necessary to form a robust winner effect comparable to that formed by California mice, but are unable to endogenously activate this machinery after achieving winning experiences. We speculate that evolutionary processes, like selection, operate on the physiological substrates that govern post-victory T release to guide divergence in the winner effect between these two species.

  10. Perspectives on the 2010 Nobel Prize in physics for graphene.

    PubMed

    Dresselhaus, Mildred S; Araujo, Paulo T

    2010-11-23

    The 2010 Nobel Prize in physics was awarded to Andre Geim and Konstantin Novoselov for their groundbreaking experiments regarding the two-dimensional material graphene. Some personal perspectives about this award are presented.

  11. Iranian PhD student wins human-rights prize

    NASA Astrophysics Data System (ADS)

    Cartwright, Jon

    2013-11-01

    A physicist imprisoned in Iran while on a break from his PhD studies in the US has been awarded a human-rights prize. Omid Kokabee, who had been based at the University of Texas in Austin, has been given the Andrei Sakharov Prize from the American Physical Society (APS) for "his courage in refusing to use his physics knowledge to work on projects that he deemed harmful to humanity, in the face of extreme physical and psychological pressure".

  12. Innate immunity's path to the Nobel Prize 2011 and beyond.

    PubMed

    Wagner, Hermann

    2012-05-01

    The 2011 Nobel Prize in Physiology/Medicine to Ralph Steinmann, Jules Hoffmann, and Bruce Beutler recognized a paradigm shift in our understanding of innate immunity, and its impact on adaptive immunity. The Prize highlighted the initial discoveries of Toll's role in immunity in flies, Toll-like receptors in mammals, and the establishment of dendritic cells as the initiators of adaptive immunity. This historical Commentary focuses on the developments in our understanding of innate immunity.

  13. [Telomeres: a Nobel Prize at the beginning… of the end].

    PubMed

    Rajpar, Shanna; Guittat, Lionel; Mergny, Jean-Louis

    2011-10-01

    The 2009 Nobel Prize for Physiology and Medicine was awarded to Elizabeth H. Blackburn, Carol W. Greider and Jack K. Szostak for their work on telomeres and telomerase. This prize acknowledges their pionneering discoveries on chromosomal extremities. Telomeres are the nucleoproteic complexes that may be found at the ends of linear chromosomes. They are essential for genomic stability and are involved in aging and tumorogenesis.

  14. PREFACE: 13th International Workshop on Slow Positron Beam Techniques and Applications (SLOPOS13)

    NASA Astrophysics Data System (ADS)

    2014-04-01

    These proceedings originate from the 13th International Workshop on Slow Positron Beam Techniques and Applications SLOPOS13 which was held at the campus of the Technische Universität München in Garching between 15th-20th September, 2013. This event is part of a series of triennial SLOPOS conferences. In total 123 delegates from 21 countries participated in the SLOPOS13. The excellent scientific program comprised 50 talks and 58 posters presented during two poster sessions. It was very impressive to learn about novel technical developments on positron beam facilities and the wide range of their applications all over the world. The workshop reflected the large variety of positron beam experiments covering fundamental studies, e.g., for efficient production of anti-hydrogen as well as applied research on defects in bulk materials, thin films, surfaces, and interfaces. The topics comprised: . Positron transport and beam technology . Pulsed beams and positron traps . Defect profiling in bulk and layered structures . Nanostructures, porous materials, thin films . Surfaces and interfaces . Positronium formation and emission . Positron interactions with atoms and molecules . Many positrons and anti-hydrogen . Novel experimental techniques The international advisory committee of SLOPOS awarded student prizes for the best presented scientific contributions to a team of students from Finland, France, and the NEPOMUC team at TUM. The conference was overshadowed by the sudden death of Professor Klaus Schreckenbach immediately before the workshop. In commemoration of him as a spiritus rectus of the neutron induced positron source a minutes' silence was hold. We are most grateful for the hard work of the Local Organising Committee, the help of the International Advisory Committee, and all the students for their friendly and efficient support during the meeting. The workshop could not have occurred without the generous support of the Heinz Maier-Leibnitz Zentrum (MLZ), Deutsche

  15. Positron-acoustic shock waves associated with cold viscous positron fluid in superthermal electron-positron-ion plasmas

    SciTech Connect

    Uddin, M. J. Alam, M. S.; Mamun, A. A.

    2015-06-15

    A theoretical investigation is made on the positron-acoustic (PA) shock waves (SHWs) in an unmagnetized electron-positron-ion plasma containing immobile positive ions, cold mobile positrons, and hot positrons and electrons following the kappa (κ) distribution. The cold positron kinematic viscosity is taken into account, and the reductive perturbation method is used to derive the Burgers equation. It is found that the viscous force acting on cold mobile positron fluid is a source of dissipation and is responsible for the formation of the PA SHWs. It is also observed that the fundamental properties of the PA SHWs are significantly modified by the effects of different parameters associated with superthermal (κ distributed) hot positrons and electrons.

  16. Positron microanalysis with high intensity beams

    SciTech Connect

    Hulett, L.D. Jr.; Donohue, D.L.

    1990-01-01

    One of the more common applications for a high intensity slow positron facility will be microanalysis of solid materials. In the first section of this paper some examples are given of procedures that can be developed. Since most of the attendees of this workshop are experts in positron spectroscopy, comprehensive descriptions will be omitted. With the exception of positron emission microscopy, most of the procedures will be based on those already in common use with broad beams. The utility of the methods have all been demonstrated, but material scientists use very few of them because positron microbeams are not generally available. A high intensity positron facility will make microbeams easier to obtain and partially alleviate this situation. All microanalysis techniques listed below will have a common requirement, which is the ability to locate the microscopic detail or area of interest and to focus the positron beam exclusively on it. The last section of this paper is a suggestion of how a high intensity positron facility might be designed so as to have this capability built in. The method will involve locating the specimen by scanning it with the microbeam of positrons and inducing a secondary electron image that will immediately reveal whether or not the positron beam is striking the proper portion of the specimen. This scanning positron microscope' will be a somewhat prosaic analog of the conventional SEM. It will, however, be an indispensable utility that will enhance the practicality of positron microanalysis techniques. 6 refs., 1 fig.

  17. "Microquasar" Discoveries Win Prize for Astronomers

    NASA Astrophysics Data System (ADS)

    The discovery of "microquasars" within our own Milky Way Galaxy has won two astronomers a prize from the High Energy Astrophysics Division of the American Astronomical Society. Felix Mirabel of the Center for Studies at Saclay, France, and Luis Rodriguez of the Institute of Astronomy at the National Autonomous University in Mexico City, were awarded the Bruno Rossi Prize at the American Astronomical Society meeting in Toronto, Ontario, today. The two researchers, who have collaborated for more than 15 years, used an orbiting X-Ray observatory and the National Science Foundation's Very Large Array (VLA) radio telescope to discover the extremely energetic microquasars. Microquasars are thought to be binary-star systems with one of the stars either a superdense neutron star or a black hole. They emit X-rays and eject jets of subatomic particles at speeds approaching that of light. Though the neutron stars or black holes in microquasars are only a few times the mass of the sun, the phenomena associated with them, such as the jets, are similar to those seen in active galaxies and quasars, believed to be powered by the gravitational energy of black holes with millions of times the mass of the sun. As such, the microquasars provide much closer "laboratories" for study of these phenomena, which remain poorly understood. The Rossi Prize is awarded for "a significant contribution to high energy astrophysics, with particular emphasis on recent work," according to the High Energy Astrophysics Division. Mirabel and Rodriguez began the research that led to the microquasar discoveries in 1990. Using the French-Russian SIGMA- GRANAT X-Ray satellite, they discovered a microquasar near the Milky Way's center in 1992. With the VLA, they found radio emission from this object. In 1992, using the same satellite, they discovered a similar object, called GRS 1915+105. In 1994, that object experienced an outburst that made it bright enough at radio wavelengths to observe with the VLA

  18. Chandra Telescope Designer Wins 2002 Rossi Prize

    NASA Astrophysics Data System (ADS)

    2002-01-01

    Leon Van Speybroeck of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts has been awarded the 2002 Bruno Rossi Prize of the High Energy Astrophysics Division of the American Astronomical Society. The Rossi Prize recognizes significant contributions in high-energy astrophysics. It is awarded annually in honor of the late Massachusetts Institute of Technology Professor Bruno Rossi, an authority on cosmic ray physics and a pioneer in the field of X-ray astronomy. The prize also includes an engraved certificate and a $1,500 award. Van Speybroeck, who led the effort to design and make the X-ray mirrors for NASA's premier X­ray observatory, the Chandra X-ray Observatory, was recognized for a career of stellar achievements in designing precision X-ray optics. As Telescope Scientist for Chandra, he has worked for more than 20 years with a team that includes scientists and engineers from the Harvard-Smithsonian, NASA's Marshall Space Flight Center, TRW, Inc., Hughes-Danbury (now B.F. Goodrich Aerospace), Optical Coating Laboratories, Inc., and Eastman-Kodak on all aspects of the X-ray mirror assembly that is the heart of the observatory. "Leon is one of the master mirror designers of our time," said Harvey Tananbaum, director of the Chandra X-ray Center. "His contributions were crucial to the spectacular success of the Chandra mission." The Chandra mirrors are the most precise mirrors ever made, smooth with tolerances of a few atoms. If the state of Colorado had the same relative smoothness as the surface of the Chandra X-ray Observatory mirrors, Pike's Peak would be less than an inch tall. The smoothness and alignment of the Chandra's mirrors are enabling scientists to make new discoveries about black holes, neutron stars, and galactic explosions. "Many, many other people made essential contributions to the Chandra program, and hopefully some of them will receive proper recognition," said Van Speybroeck. "In the meantime, I am thoroughly enjoying

  19. Slow positron beam generator for lifetime studies

    NASA Technical Reports Server (NTRS)

    Singh, Jag J. (Inventor); Eftekhari, Abe (Inventor); St.clair, Terry L. (Inventor)

    1991-01-01

    A slow positron beam generator uses a conductive source residing between two test films. Moderator pieces are placed next to the test film on the opposite side of the conductive source. A voltage potential is applied between the moderator pieces and the conductive source. Incident energetic positrons: (1) are emitted from the conductive source; (2) are passed through test film; and (3) isotropically strike moderator pieces before diffusing out of the moderator pieces as slow positrons, respectively. The slow positrons diffusing out of moderator pieces are attracted to the conductive source which is held at an appropriate potential below the moderator pieces. The slow positrons have to pass through the test films before reaching the conductive source. A voltage is adjusted so that the potential difference between the moderator pieces and the conductive source forces the positrons to stop in the test films. Measurable annihilation radiation is emitted from the test film when positrons annihilate (combine) with electrons in the test film.

  20. Materials analysis using positron beam lifetime spectroscopy

    SciTech Connect

    Hartley, J.; Howell, R. H., Asoka-Kumar, P.; Sterne, P.; Stoeffl, W.

    1998-11-12

    We are using a defect analysis capabilities based on two positron beam lifetime spectrometers: the first is based on a 3 MeV electrostatic accelerator and the second on our high current linac beam. The high energy beam lifetime spectrometer is routinely used to perform positron lifetime analysis with a 3 MeV positron beam on thick sample specimens. It is being used for bulk sample analysis and analysis of samples encapsulated in controlled environments for in situ measurements. A second, low energy, microscopically focused, pulsed positron beam for defect analysis by positron lifetime spectroscopy is under development at the LLNL high current positron source. This beam will enable defect-specific, 3-dimensional maps of defect concentration with sub-micron location resolution. When coupled with first principles calculations of defect specific positron lifetimes it will enable new levels of defect concentration mapping and defect identification.

  1. High intensity positron program at LLNL

    SciTech Connect

    Asoka-Kumar, P.; Howell, R.H.; Stoeffl, W.

    1998-09-23

    Lawrence Livermore National Laboratory (LLNL) is the home of the world's highest current beam of keV positrons. The potential for establishing a national center for materials analysis using positron annihilation techniques around this capability is being actively pursued. The high LLNL beam current will enable investigations in several new areas. We are developing a positron microprobe that will produce a pulsed, focused positron beam for 3-dimensional scans of defect size and concentration with submicron resolution. Below we summarize the important design features of this microprobe. Several experimental end stations will be available that can utilize the high current beam with a time distribution determined by the electron linac pulse structure, quasi-continuous, or bunched at 20 MHz, and can operate in an electrostatic or (and) magnetostatic environment. Some of the planned early experiments are: two-dimensional angular correlation of annihilation radiation of thin films and buried interfaces, positron diffraction holography, positron induced desorption, and positron induced Auger spectra.

  2. Spin polarized low-energy positron source

    NASA Astrophysics Data System (ADS)

    Petrov, V. N.; Samarin, S. N.; Sudarshan, K.; Pravica, L.; Guagliardo, P.; Williams, J. F.

    2015-06-01

    This paper presents an investigation of spin polarization of positrons from a source based on the decay of 22Na isotopes. Positrons are moderated by transmission through a tungsten film and electrostatically focussed and transported through a 90 deg deflector to produce a slow positron beam with polarization vector normal to the linear momentum. The polarization of the beam was determined to be about 10% by comparison with polarized electron scattering asymmetries from a thin Fe film on W(110) at 10-10 Torr. Low energy electron emission from Fe layer on W(100) surfaces under positron impact is explored. It is shown that the intensity asymmetry of the electron emission as a function of the incident positron energy can be used to estimate the polarization of the positron beam. Also several materials with long mean free paths for spin relaxation are considered as possible moderators with increased polarization of the emergent positrons.

  3. Salivary hormones and anxiety in winners and losers of an international judo competition.

    PubMed

    Papacosta, Elena; Nassis, George P; Gleeson, Michael

    2016-01-01

    The purpose of this study was to investigate the responses of salivary hormones and salivary secretory immunoglobulin A (SIgA) and anxiety in winners and losers during an international judo competition. Twenty-three trained, male, national-level judo athletes provided three saliva samples during a competition day: morning, in anticipation of competition after an overnight fast, mid-competition, and post-competition within 15 min post-fight for determination of salivary cortisol, salivary testosterone, salivary testosterone/cortisol ratio, SIgA absolute concentrations, SIgA secretion rate and saliva flow rate. The competitive state anxiety inventory questionnaire was completed by the athletes (n = 12) after the first saliva collection for determination of somatic anxiety, cognitive anxiety and self-confidence. Winners were considered 1-3 ranking place (n = 12) and losers (n = 11) below third place in each weight category. Winners presented higher anticipatory salivary cortisol concentrations (p = 0.03) and a lower mid-competition salivary testosterone/cortisol ratio (p = 0.003) compared with losers with no differences for salivary testosterone. Winners tended to have higher SIgA secretion rates (p = 0.07) and higher saliva flow rates (p = 0.009) at mid-competition. Higher levels of cognitive anxiety (p = 0.02) were observed in the winners, without differences according to the outcome in somatic anxiety and self-confidence. The results suggest that winners experienced higher levels of physiological arousal and better psychological preparedness in the morning, and as the competition progressed, the winners were able to control their stress response better.

  4. Amount of earnings during prize contingency management treatment is associated with posttreatment abstinence outcomes.

    PubMed

    Petry, Nancy M; Roll, John M

    2011-12-01

    Contingency management (CM) treatments that provide patients with the opportunity to earn chances of winning prizes of varying magnitudes are becoming increasingly popular. In the CM literature, magnitude of reinforcement is linked with effect sizes, such that CM treatments that provide larger magnitude reinforcement are more efficacious than those that provide lower magnitude reinforcement. With prize CM, even when magnitudes of overall expected prize earnings are constant, some patients win more prizes than others. Thus, patients who win larger overall amounts of prizes during treatment may have better outcomes than those who win fewer prizes. This study evaluated the impact of overall amounts of prizes won on long-term abstinence outcomes. The dollar amount of prizes won during prize CM treatments was determined from 78 cocaine-abusing methadone-maintenance patients who were randomized to prize CM treatments in three clinical trials. Abstinence three months following the end of the CM intervention was the primary dependent variable. The dollar amount of prizes won during CM treatment was a significant predictor of submission of cocaine-negative urine samples and self-reports of cocaine abstinence at the follow-up evaluation, even after controlling for other variables associated with long-term abstinence, such as pretreatment urinalysis results and longest duration of abstinence achieved during treatment. These results suggest that magnitudes of earnings during prize CM may impact outcomes and call for further experimentation of parameters related to the efficacy of prize CM.

  5. Capture and polarization of positrons in a proposed NLC polarized positron source

    SciTech Connect

    Batygin, Yuri K

    2003-05-28

    A proposed NLC polarized positron source utilizes a 150 GeV electron beam passing through a helical undulator. The resulting flux of polarized photons is converted in a thin positron production target. Spin polarized positrons are captured using a high field flux concentrator followed by an accelerator section immersed in a solenoidal field. Positron tracking through the accelerating and focusing systems is done together with integration of spin precession. Optimization of the collection system is performed to insure high positron yield into the 6-dimensional acceptance of the subsequent pre-damping ring while keeping the high value of positron beam polarization.

  6. Positron confinement in embedded lithium nanoclusters

    NASA Astrophysics Data System (ADS)

    van Huis, M. A.; van Veen, A.; Schut, H.; Falub, C. V.; Eijt, S. W.; Mijnarends, P. E.; Kuriplach, J.

    2002-02-01

    Quantum confinement of positrons in nanoclusters offers the opportunity to obtain detailed information on the electronic structure of nanoclusters by application of positron annihilation spectroscopy techniques. In this work, positron confinement is investigated in lithium nanoclusters embedded in monocrystalline MgO. These nanoclusters were created by means of ion implantation and subsequent annealing. It was found from the results of Doppler broadening positron beam analysis that approximately 92% of the implanted positrons annihilate in lithium nanoclusters rather than in the embedding MgO, while the local fraction of lithium at the implantation depth is only 1.3 at. %. The results of two-dimensional angular correlation of annihilation radiation confirm the presence of crystalline bulk lithium. The confinement of positrons is ascribed to the difference in positron affinity between lithium and MgO. The nanocluster acts as a potential well for positrons, where the depth of the potential well is equal to the difference in the positron affinities of lithium and MgO. These affinities were calculated using the linear muffin-tin orbital atomic sphere approximation method. This yields a positronic potential step at the MgO||Li interface of 1.8 eV using the generalized gradient approximation and 2.8 eV using the insulator model.

  7. 77 FR 56697 - Culturally Significant Objects Imported for Exhibition Determinations: “The English Prize: The...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-13

    ... for Exhibition Determinations: ``The English Prize: The Capture of the Westmorland, an Episode of the..., 2003), I hereby determine that the objects to be included in the exhibition ``The English Prize:...

  8. Nonplanar positron-acoustic Gardner solitary waves in electron-positron-ion plasmas with superthermal electrons and positrons

    NASA Astrophysics Data System (ADS)

    Uddin, M. J.; Alam, M. S.; Mamun, A. A.

    2015-02-01

    Nonplanar (cylindrical and spherical) positron-acoustic (PA) Gardner solitary waves (SWs) in an unmagnetized plasma system consisting of immobile positive ions, mobile cold positrons, and superthermal (kappa distributed) hot positrons and electrons are investigated. The modified Gardner equation is derived by using the reductive perturbation technique. The effects of cylindrical and spherical geometries, superthermal parameter of hot positrons and electrons, relative temperature ratios, and relative number density ratios on the PA Gardner SWs are studied by using the numerical simulations. The implications of our results in various space and laboratory plasma environments are briefly discussed.

  9. Nonplanar positron-acoustic Gardner solitary waves in electron-positron-ion plasmas with superthermal electrons and positrons

    SciTech Connect

    Uddin, M. J. Alam, M. S.; Mamun, A. A.

    2015-02-15

    Nonplanar (cylindrical and spherical) positron-acoustic (PA) Gardner solitary waves (SWs) in an unmagnetized plasma system consisting of immobile positive ions, mobile cold positrons, and superthermal (kappa distributed) hot positrons and electrons are investigated. The modified Gardner equation is derived by using the reductive perturbation technique. The effects of cylindrical and spherical geometries, superthermal parameter of hot positrons and electrons, relative temperature ratios, and relative number density ratios on the PA Gardner SWs are studied by using the numerical simulations. The implications of our results in various space and laboratory plasma environments are briefly discussed.

  10. Positron annihilation induced Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Weiss, Alex; Koymen, A. R.; Mehl, David; Jensen, K. O.; Lei, Chun; Lee, K. H.

    1990-01-01

    Recently, Weiss et al. have demonstrated that it is possible to excite Auger transitions by annihilating core electrons using a low energy (less than 30eV) beam of positrons. This mechanism makes possible a new electron spectroscopy, Positron annihilation induced Auger Electron Spectroscopy (PAES). The probability of exciting an Auger transition is proportional to the overlap of the positron wavefunction with atomic core levels. Since the Auger electron energy provides a signature of the atomic species making the transition, PAES makes it possible to determine the overlap of the positron wavefunction with a particular element. PAES may therefore provide a means of detecting positron-atom complexes. Measurements of PAES intensities from clean and adsorbate covered Cu surfaces are presented which indicate that approx. 5 percent of positrons injected into CU at 25eV produce core annihilations that result in Auger transitions.

  11. Positron annihilation in the interstellar medium

    NASA Technical Reports Server (NTRS)

    Guessoum, Nidhal; Ramaty, Reuven; Lingenfelter, Richard E.

    1991-01-01

    Positronium formation and annihilation are studied in a model for the interstellar medium consisting of cold cloud cores, warm partially ionized cloud envelopes, and hot intercloud gas. The gamma-ray spectra resulting from positron annihilation in these components of the interstellar medium are calculated. The spectra from the individual components are then combined, using two limiting assumptions for the propagation of the positrons, namely, that the positrons propagate freely throughout the interstellar medium, and that the positrons are excluded from the cold cloud cores. In the first case, the bulk of the positrons annihilate in the cloud cores and the annihilation line exhibits broad wings resulting from the annihilation of positronium formed by charge exchange in flight. In the second case, the positrons annihilate mainly in the warm envelopes, and the line wings are suppressed.

  12. Irish Team Wins SEA & SPACE Super Prize

    NASA Astrophysics Data System (ADS)

    1998-09-01

    A secondary school team from Ireland has won a trip to Europe's Spaceport in Kourou, French Guyana, and to ESO's Very Large Telescope (VLT) at Cerro Paranal, Chile. The trip is the Super-Prize for the Sea & Space Newspaper Competition , organised within the framework of the European Week for Scientific and Technological Culture. ESO PR Photo 33/98 ESO PR Photo 33/98 [Preview - JPEG: 800 x 434 pix - 568k] [High-Res - JPEG: 3000 x 1627 pix - 6.7Mb] The presentation of prize certificates to the winning Irish team (right) in Lisbon, on August 31, 1998, by ESO, ESA and EAAE representatives. Stephen Kearney, Cian Wilson (both aged 16 years), Eamonn McKeogh (aged 17 years) together with their teacher, John Daly of Blackrock College in Dublin, prepared their newspaper, Infinitus , on marine and space themes, and came first in the national round of the competition. Together with other students from all over Europe, they were invited to present their winning newspaper to a jury consisting of representatives of the organisers, during a special programme of events at the Gulbenkian Planetarium and EXPO '98 in Lisbon, from 28-31 August, 1998. The Irish team scored highly in all categories of the judging, which included scientific content and originality and creativity of the articles. Their look at Irish contributions to sea and space research also proved popular in a ballot by fellow student competitors. This vote was also taken into account by the judges. The jury was very impressed by the high quality of the national entries and there were several close runners-up. The width and depth was amazing and the variety of ideas and formats presented by the sixteen teams was enormous. A poster competition was organised for younger students, aged 10 to 13 and winning entries at national level are on display at the Oceanophilia Pavilion at EXPO '98. The SEA & SPACE project is a joint initiative of the European Space Agency (ESA) , the European Southern Observatory (ESO) , and the

  13. Ecosystems Vulnerability Challenge and Prize Competition

    NASA Astrophysics Data System (ADS)

    Smith, J. H.; Frame, M. T.; Ferriter, O.; Recker, J.

    2014-12-01

    Stimulating innovation and private sector entrepreneurship is an important way to advance the preparedness of communities, businesses and individuals for the impacts of climate change on certain aspects of ecosystems, such as: fire regimes; water availability; carbon sequestration; biodiversity conservation; weather-related hazards, and the spread of invasive species. The creation of tools is critical to help communities and natural resource managers better understand the impacts of climate change on ecosystems and the potential resulting implications for ecosystem services and conservation efforts. The Department of the Interior is leading an interagency effort to develop the Ecosystems Vulnerability theme as part of the President's Climate Action Plan. This effort will provide seamless access to relevant datasets that can help address such issues as: risk of wildfires to local communities and federal lands; water sensitivity to climate change; and understanding the role of ecosystems in a changing climate. This session will provide an overview of the proposed Ecosystem Vulnerability Challenge and Prize Competition, outlining the intended audience, scope, goals, and overall timeline. The session will provide an opportunity for participants to offer new ideas. Through the Challenge, access will be made available to critical datasets for software developers, engineers, scientists, students, and researchers to develop and submit applications addressing critical science issues facing our Nation today. Application submission criteria and guidelines will also be discussed. The Challenge will be open to all sectors and organizations (i.e. federal, non-federal, private sector, non-profits, and universities) within the United States. It is anticipated the Challenge will run from early January 2015 until spring of 2015.

  14. Randomized Trial of Prize-Based Reinforcement Density for Simultaneous Abstinence from Cocaine and Heroin

    ERIC Educational Resources Information Center

    Ghitza, Udi E.; Epstein, David H.; Schmittner, John; Vahabzadeh, Massoud; Lin, Jia-Ling; Preston, Kenzie L.

    2007-01-01

    To examine the effect of reinforcer density in prize-based abstinence reinforcement, heroin/cocaine users (N = 116) in methadone maintenance (100 mg/day) were randomly assigned to a noncontingent control group (NonC) or to 1 of 3 groups that earned prize draws for abstinence: manual drawing with standard prize density (MS) or computerized drawing…

  15. Positron study of annealing of gallium arsenide

    SciTech Connect

    Rice-Evans, P.C.; Smith, D.L.; Evans, H.E.; Gledhill, G.A. )

    1991-02-01

    A positron beam has been used to investigate the sub-surface changes in semi-insulating gallium arsenide which had been annealed to a range of temperatures. The variations of the Doppler S parameter as a function of positron implantation energy, when subjected to a diffusion analysis, indicate variations in positron trapping at different depths. The results indicate the changes in the type of point defect that accompany the annealing.

  16. Engagement of National Winners of the 2006 All-USA Community College Academic Team while Attending Senior Colleges

    ERIC Educational Resources Information Center

    Risley, Rod; King, Stephanie B.

    2012-01-01

    All-USA Community College Academic Team national winners attending senior colleges were compared with both a general population of community college transfer students as well as senior college native students based on their responses to the National Survey on Student Engagement (NSSE). Results indicated that the national winners' levels of…

  17. A Winner Determination Algorithm for Combinatorial Auctions Based on Hybrid Artificial Fish Swarm Algorithm

    NASA Astrophysics Data System (ADS)

    Zheng, Genrang; Lin, ZhengChun

    The problem of winner determination in combinatorial auctions is a hotspot electronic business, and a NP hard problem. A Hybrid Artificial Fish Swarm Algorithm(HAFSA), which is combined with First Suite Heuristic Algorithm (FSHA) and Artificial Fish Swarm Algorithm (AFSA), is proposed to solve the problem after probing it base on the theories of AFSA. Experiment results show that the HAFSA is a rapidly and efficient algorithm for The problem of winner determining. Compared with Ant colony Optimization Algorithm, it has a good performance with broad and prosperous application.

  18. Initial results of positron ionization mass spectrometry

    NASA Technical Reports Server (NTRS)

    Donohue, D. L.; Hulett, L. D., Jr.; Mcluckey, S. A.; Glish, G. L.; Eckenrode, B. A.

    1990-01-01

    The use of monoenergetic positrons for the ionization of organic molecules in the gas phase is described. The ionic products are analyzed with a time-of-flight mass spectrometer and detected to produce a mass spectrum. The ionization mechanisms which can be studied in this way include positron impact at energies above the ionization limit of the target molecules, positronium formation in the Ore gap energy range, and positron attachment at energies less than 1eV. The technique of positron ionization mass spectrometry (PIMS) may have analytical utility in that chemical selectivity is observed for one or more of these processes.

  19. Applications and advances of positron beam spectroscopy

    SciTech Connect

    Howell, R., LLNL

    1998-03-18

    Over 50 scientists from DOE-DP, DOE-ER, the national laboratories, academia and industry attended a workshop held on November 5-7, 1997 at Lawrence Livermore National Laboratory. Workshop participants were charged to address two questions: Is there a need for a national center for materials analysis using positron techniques and can the capabilities at Lawrence Livermore National Laboratory serve this need. To demonstrate the need for a national center, the workshop participants discussed the technical advantages enabled by high positron currents and advanced measurement techniques, the role that these techniques would play in materials analysis and the demand for the data. Livermore now leads the world in materials analysis capabilities by positrons due to developments in response to demands of stockpile stewardship. The Livermore facilities now include the world`s highest current beam of keV positrons, a scanning pulsed positron microprobe under development capable of three dimensional maps of defect size and concentration, an MeV positron beam for defect analysis of large samples, and electron momentum spectroscopy by positrons. It was concluded that the positron microprobe under development at LLNL and other new instruments that would be relocated at LLNL at the high current keV source are an exciting step forward in providing results for the positron technique. These new data will impact a wide variety of applications.

  20. Duncan Tanner Essay Prize Winner 2014. Against the 'Sacred Cow': NHS Opposition and the Fellowship for Freedom in Medicine, 1948-72.

    PubMed

    Seaton, Andrew

    2015-01-01

    This essay recovers organized opposition to the National Health Service (NHS) by considering the Fellowship for Freedom in Medicine (FFM), a conservative organization of doctors who challenged the 'Sacred Cow' of nationalized healthcare in the 1950s and 1960s. While there has been little interest in anti-NHS politics because of shortcomings in the institution's historiography, this study suggests ways a new history of the service can be written. Central to that project is taking the broader ideological and emotive quality of the NHS seriously, and appreciating the way, for all sides of the political spectrum, as well as the general public, the service has always been a contested symbol of post-war British identity. This essay argues that two NHS 'crises'--panics over costs, and disillusionment within general practice--were not merely disagreements over budgets and pay-packets but politically charged moments infused with conservative anxieties over Britain's post-war trajectory. The FFM imagined the NHS as an economically dangerous bureaucratic machine that crushed medical independence and risked pushing the country towards dictatorship. Allies within the Conservative Party, private health insurance industry, and free-market 'think-tanks' worked with the FFM to challenge defences of both the service's operation and meaning. To appreciate why the NHS remains 'the closest thing the English have to a religion', one must consider the apostates as well as the faithful.

  1. Matrix Isolation Spectroscopy Applied to Positron Moderatioin in Cryogenic Solids

    DTIC Science & Technology

    2011-07-01

    nanoseconds. Positrons that reach a free surface of the moderator before annihilating with an electron may escape into vacuum where they can be...0324. 3 • The positron (e+) is the antiparticle to the electron (e-). • Positrons are stable, but annihilate with electrons to produce γ-rays...Current Positron Applications • 2-γ decay exploited in Positron Emission Tomography (PET) scanners. • Positrons localize & annihilate preferentially at

  2. On the method of positron lifetime measurement

    NASA Technical Reports Server (NTRS)

    Nishiyama, F.; Shizuma, K.; Nasai, H.; Nishi, M.

    1983-01-01

    A fast-slow coincidence system was constructed for the measurement of positron lifetimes in material. The time resolution of this system was 270 ps for the (60)Co gamma rays. Positron lifetime spectra for 14 kinds of alkali halides were measured with this system. Two lifetime components and their intensities were derived from analyses of the lifetime spectra.

  3. Descriptions of positron defect analysis capabilities

    SciTech Connect

    Howell, R.H.

    1994-10-01

    A series of descriptive papers and graphics appropriate for distribution to potential collaborators has been assembled. These describe the capabilities for defect analysis using positron annihilation spectroscopy. The application of positrons to problems in the polymer and semiconductor industries is addressed.

  4. 21 CFR 892.1110 - Positron camera.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Positron camera. 892.1110 Section 892.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1110 Positron camera. (a) Identification. A...

  5. 21 CFR 892.1110 - Positron camera.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Positron camera. 892.1110 Section 892.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1110 Positron camera. (a) Identification. A...

  6. 21 CFR 892.1110 - Positron camera.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Positron camera. 892.1110 Section 892.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1110 Positron camera. (a) Identification. A...

  7. 21 CFR 892.1110 - Positron camera.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Positron camera. 892.1110 Section 892.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1110 Positron camera. (a) Identification. A...

  8. 21 CFR 892.1110 - Positron camera.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Positron camera. 892.1110 Section 892.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1110 Positron camera. (a) Identification. A...

  9. Ionisation of atomic hydrogen by positron impact

    NASA Technical Reports Server (NTRS)

    Spicher, Gottfried; Olsson, Bjorn; Raith, Wilhelm; Sinapius, Guenther; Sperber, Wolfgang

    1990-01-01

    With the crossed beam apparatus the relative impact-ionization cross section of atomic hydrogen by positron impact was measured. A layout of the scattering region is given. The first measurements on the ionization of atomic hydrogen by positron impact are also given.

  10. Positron collisions with alkali-metal atoms

    NASA Technical Reports Server (NTRS)

    Gien, T. T.

    1990-01-01

    The total cross sections for positron and electron collisions with potassium, sodium, lithium and rubidium are calculated, employing the modified Glauber approximation. The Modified Glauber cross sections for positron collision with potassium and sodium at low intermediate energies are found to agree reasonably well with existing experimental data.

  11. Electron and Positron Stopping Powers of Materials

    National Institute of Standards and Technology Data Gateway

    SRD 7 NIST Electron and Positron Stopping Powers of Materials (PC database for purchase)   The EPSTAR database provides rapid calculations of stopping powers (collisional, radiative, and total), CSDA ranges, radiation yields and density effect corrections for incident electrons or positrons with kinetic energies from 1 keV to 10 GeV, and for any chemically defined target material.

  12. Nondestructive examination using neutron activated positron annihilation

    DOEpatents

    Akers, Douglas W.; Denison, Arthur B.

    2001-01-01

    A method is provided for performing nondestructive examination of a metal specimen using neutron activated positron annihilation wherein the positron emitter source is formed within the metal specimen. The method permits in situ nondestructive examination and has the advantage of being capable of performing bulk analysis to determine embrittlement, fatigue and dislocation within a metal specimen.

  13. Selecting Quality Literature for Your Child: Lessons from the Caldecott Award Winners.

    ERIC Educational Resources Information Center

    Stern, Lois W.

    The Caldecott Awards are presented annually for the most distinguished American picture book(s) published for children. Invariably these books are well written and illustrated and frequently touch an inner core. Here are some of the messages the Caldecott winners can pass along: a book should be a pleasure to hear; a book should help a child…

  14. The Greatest Story Never Told: An Interview with National Book Award Winner Phillip Hoose

    ERIC Educational Resources Information Center

    Aronson, Marc

    2010-01-01

    This article presents an interview with Phillip Hoose, National Book Award winner for young people's literature for his book "Claudette Colvin: Twice Toward Justice," a true story of a teen who refused to surrender her seat to a white passenger on a segregated bus in Montgomery, Alabama. Hoose is no stranger to the world of literary honors. His…

  15. ACCE/ACS National Educator and Leader of the Year Winners: AEC Congratulates These Outstanding Educators

    ERIC Educational Resources Information Center

    Australian Educational Computing, 2012

    2012-01-01

    This article presents the ACCE/ACS National Educator and Leader of the Year winners. Anne Mirtschin is the recipient of the ACCE/ACS 2012 Educator of the Year Award. Mirtschin is an innovative teacher at Hawkesdale P-12 College a small rural school that is isolated culturally and geographically. She uses online tools and technology to create…

  16. Winners of the First 1960 Televised Presidential Debate between Kennedy and Nixon.

    ERIC Educational Resources Information Center

    Kraus, Sidney

    1996-01-01

    Reviews the events, studies, and comments (from 1960 to the present) regarding the controversial question of who won the first 1960 televised debate between John F. Kennedy and Richard M. Nixon. Supports the view that, for television viewers, Kennedy was the winner, whereas radio listeners gave Nixon the edge. (SR)

  17. University of Maryland Named Winner of EPA Campus RainWorks Challenge

    EPA Pesticide Factsheets

    PHILADELPHIA (April 22, 2015) The U.S. Environmental Protection Agency today announced the University of Maryland as a winner of its third annual Campus RainWorks Challenge, a design competition created to engage college and university students in r

  18. Coretta Scott King Award Winner Javaka Steptoe Stands Tall "In Daddy's Arms."

    ERIC Educational Resources Information Center

    Peck, Jackie; Hendershot, Judy

    1999-01-01

    Offers an interview with artist and author Javaka Steptoe, winner of the Coretta Scott King award for his book "In Daddy's Arms I Am Tall: African Americans Celebrating Fathers." Discusses his background in the arts, the variety of media he uses, how he begins thinking about his illustrations, his work with children's art, and aspects of his work.…

  19. 2016 Federal Green Challenge Award Winners in the Great Lakes Region

    EPA Pesticide Factsheets

    2016 FGC award winners in the Great Lakes region: Mpls. Veterans Affairs (VA) Healthcare System, MN National Guard, U.S. EPA Mid-Continent Ecology Division, U.S. Customs and Border Protection Detroit Field Office, and Naval Station Great Lakes.

  20. The Great Unknown: Daniel Handler Interviews National Book Award-Winner Judy Blundell

    ERIC Educational Resources Information Center

    Handler, Daniel

    2009-01-01

    This article presents an interview with National Book Award-winner Judy Blundell. For nearly 20 years, Blundell has toiled in anonymity, turning out more than 100 mysteries, romances, and media tie-ins under various pen names, such as Jude Watson. But in mid-November, the writer-for-hire was suddenly shoved into the spotlight. That's when "What I…

  1. Permanence and Stability of a Kill the Winner Model in Marine Ecology.

    PubMed

    Korytowski, Daniel A; Smith, Hal

    2017-03-27

    We focus on the long-term dynamics of "killing the winner" Lotka-Volterra models of marine communities consisting of bacteria, virus, and zooplankton. Under suitable conditions, it is shown that there is a unique equilibrium with all populations present which is stable, the system is permanent, and the limiting behavior of its solutions is strongly constrained.

  2. CEFPI 2000 Design Portfolio: James D. MacConnell Award Winner.

    ERIC Educational Resources Information Center

    Educational Facility Planner, 2000

    2000-01-01

    Presents an architectural description of the Edmonds-Woodway High School (Washington), winner of the James D. MacConnel Award from the Council of Educational Facility Planners, International. Photos, floor plans, and project data and school statistics are included. (GR)

  3. Positronic complexes with unnatural parity

    SciTech Connect

    Bromley, M. W. J.; Mitroy, J.; Varga, K.

    2007-06-15

    The structure of the unnatural parity states of PsH, LiPs, NaPs, and KPs are investigated with the configuration interaction and stochastic variational methods. The binding energies (in hartree) are found to be 8.17x10{sup -4}, 4.42x10{sup -4}, 15.14x10{sup -4}, and 21.80x10{sup -4}, respectively. These states are constructed by first coupling the two electrons into a configuration which is predominantly {sup 3}P{sup e}, and then adding a p-wave positron. All the active particles are in states in which the relative angular momentum between any pair of particles is at least L=1. The LiPs state is Borromean since there are no three-body bound subsystems (of the correct symmetry) of the (Li{sup +}, e{sup -}, e{sup -}, e{sup +}) particles that make up the system. The dominant decay mode of these states will be radiative decay into a configuration that autoionizes or undergoes positron annihilation.

  4. Pat Thiel talks about attending the Nobel Prize Award Ceremony

    SciTech Connect

    Thiel, Pat

    2012-01-01

    Pat Thiel, Ames Laboratory senior scientist and Iowa State University Distinguished Professor of Chemistry, was invited to be a guest at the ceremony on December 10th, in Stockholm, Sweden, where Danny Shechtman, Ames Laboratory scientist, received the 2011 Nobel Prize in Chemistry. Following her return to the Lab, Thiel shared some of her recollections of the momentous event.

  5. Training Quality: Before and after Winning the Deming Prize.

    ERIC Educational Resources Information Center

    Magennis, Jo P.

    1995-01-01

    Describes the Quality Improvement Program developed by Florida Power and Light's Nuclear Training organization that was awarded the Deming Application Prize for quality control. Training quality, team activities, training's role in business planning, customer involvement and evaluation, and continuous improvement of training are discussed. (LRW)

  6. SunShot Catalyst Prize Competition Fact Sheet

    SciTech Connect

    Solar Energy Technologies Office

    2015-04-01

    This fact sheet is an overview of the Catalyst Energy Innovation Prize, an open innovation program launched in 2014 by the U.S. Department of Energy SunShot Initiative. This program aims to catalyze the rapid creation and development of products and solutions that address near-term challenges in the U.S. solar energy marketplace.

  7. The Competition "First Step to Nobel Prize in Physics"

    ERIC Educational Resources Information Center

    Gorzkowski, W.; Surya, Y; Zuberek, R

    2011-01-01

    This paper presents the history of the competition First Step to Nobel Prize in Physics organized by Poland, its development from a national workshop in 1991/92 to an international competition nowadays and its organization, as well as the results obtained by the participants. (Contains 1 table.)

  8. What to do to win a Nobel prize

    NASA Astrophysics Data System (ADS)

    Foundationeer, Second; chrischievious; Hasler, John; nvrao; dedalus22; Martin

    2014-11-01

    In reply to the infographic "Illustrating a century of Nobels" and a related physicsworld.com blog post "What type of physics should you do if you want to bag a Nobel prize?" (2 October, http://ow.ly/CmCzl, see also pp22-23).

  9. Tight Focus on Instruction Wins Texas District Prize

    ERIC Educational Resources Information Center

    Maxwell, Lesli A.

    2009-01-01

    It took a while for four-time finalist Aldine, Texas, to win the Broad Prize for Urban Education. But it took even longer to craft the system that ultimately put the district over the top. Educators in Aldine district have been working for more than a decade to refine their "managed instruction" system. Reviewers examined how the school…

  10. Defining Excellence: Lessons from the 2013 Aspen Prize Finalists

    ERIC Educational Resources Information Center

    Aspen Institute, 2013

    2013-01-01

    In many respects, one couldn't find a group of 10 schools more diverse than the finalists for the 2013 Aspen Prize for Community College Excellence. One community college serves 1,500 students, another 56,000. There are institutions devoted primarily--even solely--to technical degrees, and ones devoted mainly to preparing students for further…

  11. The 2013 Aspen Prize for Community College Excellence

    ERIC Educational Resources Information Center

    Perlstein, Linda

    2013-01-01

    For millions of Americans, community colleges provide an essential pathway to well-paying jobs and continuing higher education. The Aspen Prize for Community College Excellence honors those institutions that strive for and achieve exceptional levels of success for all students, while they are in college and after they graduate. Community colleges…

  12. "Not Censorship but Selection": Censorship and/as Prizing

    ERIC Educational Resources Information Center

    Kidd, Kenneth

    2009-01-01

    This essay calls for a fresh critical approach to the topic of censorship, suggesting that anticensorship efforts, while important and necessary, function much like literary prizing. The analysis draws especially on James English's recent study "The Economy of Prestige." There are two central arguments: first, that the librarian ethic of…

  13. Physics GRE Scores of Prize Postdoctoral Fellows in Astronomy

    NASA Astrophysics Data System (ADS)

    Levesque, Emily M.; Bezanson, Rachel; Tremblay, Grant

    2017-01-01

    The Physics GRE has long been a required element of the graduate admissions process in many U.S. astronomy programs; however, its predictive power and utility as a means of selection "successful" applicants had not been quantitatively examined until recently. In the fall of 2015 we circulated a short questionnaire to 271 people who have held U.S. prize postdoctoral fellowships in astrophysics between 2010-2015, asking them to report their Physics GRE scores. The response rate was 64%, and the responding sample was unbiased with respect to the overall gender distribution of prize fellows. The responses revealed that the Physics GRE scores of prize fellows do not adhere to any minimum percentile score and show no statistically significant correlation with the number of first author papers published. As an example, a Physics GRE percentile cutoff of 60% would have eliminated 44% of 2010-2015 U.S. prize postdoctoral fellows, including 60% of the female fellows. From these data, we found no evidence that the Physics GRE could be used as an effective predictor of "success" either in or beyond graduate school. Following this work and last year's official recommendation from the AAS, several astronomy departments have recently decided to eliminate the Physics GRE as a requirement for graduate applicants.

  14. The Nobel Prize in Medicine for Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Fry, Charles G.

    2004-01-01

    Nobel Prize in Medicine awarded in December 2003 to chemist Paul C. Lauterbur and physicist Peter Mansfield for the development of magnetic resonance imaging (MRI), a long overdue recognition of the huge impact MRI has had in medical diagnostics and research is mentioned. MRI was derived, and remains an extension of nuclear magnetic resonance…

  15. Pat Thiel talks about attending the Nobel Prize Award Ceremony

    ScienceCinema

    Thiel, Pat

    2016-07-12

    Pat Thiel, Ames Laboratory senior scientist and Iowa State University Distinguished Professor of Chemistry, was invited to be a guest at the ceremony on December 10th, in Stockholm, Sweden, where Danny Shechtman, Ames Laboratory scientist, received the 2011 Nobel Prize in Chemistry. Following her return to the Lab, Thiel shared some of her recollections of the momentous event.

  16. Cracker Jacks: "Finding the Prize" inside Each Adolescent Learner

    ERIC Educational Resources Information Center

    Ellerbrock, Cheryl; DiCicco, Michael; Denmon, Jennifer M.; Parke, Erin; Mead, Sarah

    2017-01-01

    The purpose of this manuscript is to highlight several practical classroom examples of asset-driven acts of reciprocal care and content-driven community builders and icebreakers that highlight ways to "find the prize" inside each student by fostering an adolescent-centered community of care that is committed to both relationships and…

  17. Whose Big Prize? A Response to Hall and Gunter

    ERIC Educational Resources Information Center

    Furlong, John

    2009-01-01

    This article presents the author's response to Hall and Gunter who accuse the author of trying to mount "a stout defence" of New Labour's reforms of the teaching profession. Hall and Gunter go further and accuse the author of "triumphalism" in his use of the title "Tony Blair's big prize". Their second and more…

  18. Alfred Nobel and the Nobel Prizes. Fact Sheets on Sweden.

    ERIC Educational Resources Information Center

    Swedish Inst., Stockholm.

    The life and personality of Alfred Nobel and the Nobel Prizes established by his will are discussed. Nobel was a 19th century Swedish industrialist who was fluent in six languages. He invented dynamite. At his death in 1896, his estate amounted to $9,200,000. His will stipulated that the income from his estate should be divided annually into five…

  19. Lightweight Wearable Power Energized by Pentagon’s Prize Program

    DTIC Science & Technology

    2009-04-27

    the Virgin Earth Challenge under which Richard Branson and Al Gore are offering a prize of $25 million to anyone who can demonstrate a commercially...asserts Dr. Richard T. Fingers, Chief of the Energy Power Thermal Division at the Air Force Research Laboratory (AFRL) at Wright-Patterson Air Force Base

  20. How Robert A. Millikan Got the Physics Nobel Prize

    ERIC Educational Resources Information Center

    Panusch, Martin; Heering, Peter; Singh, Rajinder

    2010-01-01

    In 1923, R.A. Millikan was awarded the Nobel Prize in Physics for his work on the elementary charge of electricity and on the photoelectric effect. Recently, historical research had a focus on Millikan's publication practice, as well as on the role of his assistant, Harvey Fletcher. Several studies have raised doubts on whether Millikan can…

  1. Reclaiming "Lost Prizes": An Interview with Ken McCluskey

    ERIC Educational Resources Information Center

    Van Bockern, Steve

    2012-01-01

    This article presents an interview with Dr. Ken McCluskey, Dean and Professor of Education at the University of Winnipeg. He is known internationally for his work in several areas including: (1) mentoring; (2) attention-deficit hyperactivity disorder; (3) at-risk children and youth (where his "Lost Prizes" and related projects serve as…

  2. Prizes in Cereal Boxes: An Application of Probability.

    ERIC Educational Resources Information Center

    Litwiller, Bonnie H.; Duncan, David R.

    1992-01-01

    Presents four cases of real-world probabilistic situations to promote more effective teaching of probability. Calculates the probability of obtaining six of six different prizes successively in six, seven, eight, and nine boxes of cereal, generalizes the problem to n boxes of cereal, and offers suggestions to extend the problem. (MDH)

  3. The Progressive Insurance Automotive X PRIZE Education Program

    SciTech Connect

    Robyn Ready

    2011-12-31

    The Progressive Insurance Automotive X PRIZE Education Program conducted education and outreach activities and used the competition's technical goals and vehicle demonstrations as a means of attracting students and the public to learn more about advanced vehicle technologies, energy efficiency, climate change, alternative fuels, and the science and math behind efficient vehicle development. The Progressive Insurance Automotive X PRIZE Education Program comprised three integrated components that were designed to educate the general public and create a multi-tiered initiative to engage students and showcase the 21st century skills students will need to compete in our global economy: teamwork, creativity, strong literacy, math and science skills, and innovative thinking. The elements included an Online Experience, a National Student Contest, and in person education events and activites. The project leveraged online connections, strategic partnerships, in-classroom, and beyond-the-classroom initiatives, as well as mainstream media. This education program supported by the U.S. Department of Energy (DOE) also funded the specification of vehicle telemetry and the full development and operation of an interactive online experience that allowed internet users to follow the Progressive Insurance Automotive X PRIZE vehicles as they performed in real-time during the Progressive Insurance Automotive X PRIZE competition events.

  4. Supporting Military Veteran Students: Early Lessons from Kohlberg Prize Recipients

    ERIC Educational Resources Information Center

    Karp, Melinda Mechur; Klempin, Serena

    2016-01-01

    Postsecondary education participation is critical for military-connected individuals as they transition back to civilian life. The Kisco Foundation's Kohlberg Prize, a competitive grant awarded in 2015 and 2016, is aimed at making community colleges more welcoming and better able to meet the needs of veteran students. This review details the early…

  5. Student Intern Lands Top Prize in National Science Competition | Poster

    Cancer.gov

    By Ashley DeVine, Staff Writer Student intern Sam Pritt’s interest in improving geolocation led him to develop a project that won a top regional prize at the Siemens Competition in Math, Science, and Technology in November. Pritt was awarded a $3,000 college scholarship, and he competed in the national competition in early December.

  6. Positron beam studies of transients in semiconductors

    NASA Astrophysics Data System (ADS)

    Beling, C. D.; Ling, C. C.; Cheung, C. K.; Naik, P. S.; Zhang, J. D.; Fung, S.

    2006-02-01

    Vacancy-sensing positron deep level transient spectroscopy (PDLTS) is a positron beam-based technique that seeks to provide information on the electronic ionization levels of vacancy defects probed by the positron through the monitoring of thermal transients. The experimental discoveries leading to the concept of vacancy-sensing PDLTS are first reviewed. The major problem associated with this technique is discussed, namely the strong electric fields establish in the near surface region of the sample during the thermal transient which tend to sweep positrons into the contact with negligible defect trapping. New simulations are presented which suggest that under certain conditions a sufficient fraction of positrons may be trapped into ionizing defects rendering PDLTS technique workable. Some suggestions are made for techniques that might avoid the problematic electric field problem, such as optical-PDLTS where deep levels are populated using light and the use of high forward bias currents for trap filling.

  7. Design Issues for the ILC Positron Source

    SciTech Connect

    Bharadwaj, V.; Batygin, Yu.K.; Pitthan, R.; Schultz, D.C.; Sheppard, J.; Vincke, H.; Wang, J.W.; Gronberg, J.; Stein, W.; /LLNL, Livermore

    2006-02-15

    A positron source for the International Linear Collider (ILC) can be designed using either a multi-GeV electron beam or a multi-MeV photon beam impinging on a metal target. The major design issues are: choice of drive beam and its generation, choice of target material, the target station, positron capture section, target vault and beam transport to the ILC positron damping ring complex. This paper lists the ILC positron source requirements and their implications for the design of the positron source. A conceptual design for the ILC is expected to be finished in the next two years. With emphasis on this timescale, source design issues and possible solutions are discussed.

  8. Role of cAMP signalling in winner and loser effects in crayfish agonistic encounters.

    PubMed

    Momohara, Yuto; Minami, Hiroki; Kanai, Akihiro; Nagayama, Toshiki

    2016-07-01

    For territorial animals, establishment of status-dependent dominance order is essential to maintain social stability. In agonistic encounters of the crayfish Procambarus clarkii, a difference of body length of 3-7% is enough for larger animals to become dominant. Despite a physical disadvantage, small winners of the first pairings were more likely to win subsequent conflicts with larger inexperienced animals. In contrast, the losers of the first pairings rarely won subsequent conflicts with smaller naive animals. Such experiences of previous winning or losing affected agonistic outcomes for a long period. The winner effects lasted more than 2 weeks and the loser effect lasted about 10 days. Injection of 5HT1 receptor antagonist into the dominant animals 15-30 min after establishment of dominance order blocked the formation of the winner effects. In contrast, injection of adrenergic-like octopamine receptor antagonist into subordinate animals blocked the formation of the loser. 5HT1 receptors are negatively coupled to adenylyl cyclase and adrenergic-like octopamine receptors are positively coupled. Consistent with this, dominant animals failed to show the winner effect when injected with pCPT-cAMP, a cAMP analogue, and subordinate animals failed to show a loser effect when injected with adenylyl cyclase inhibitor SQ 22536. These results suggest that an increase and decrease of cAMP concentration is essential in mediating loser and winner effects, respectively. Furthermore, formation of the loser effect was blocked by injection of protein kinase A (PKA) inhibitor H89, suggesting long-term memory of the loser effect is dependent on the cAMP-PKA signalling pathway.

  9. Hormonal, Physiological, and Physical Performance During Simulated Kickboxing Combat: Differences Between Winners and Losers.

    PubMed

    Ouergui, Ibrahim; Davis, Philip; Houcine, Nizar; Marzouki, Hamza; Zaouali, Monia; Franchini, Emerson; Gmada, Nabil; Bouhlel, Ezzedine

    2016-05-01

    The aim of the current study was to investigate the hormonal, physiological, and physical responses of simulated kickboxing competition and evaluate if there was a difference between winners and losers. Twenty athletes of regional and national level participated in the study (mean ± SD age 21.3 ± 2.7 y, height 170.0 ± 5.0 cm). Hormone (cortisol, testosterone, growth hormone), blood lactate [La], and glucose concentrations, as well as upper-body Wingate test and countermovement-jump (CMJ) performances, were measured before and after combats. Heart rate (HR) was measured throughout rounds 1, 2, and 3 and rating of perceived exertion (RPE) was taken after each round. All combats were recorded and analyzed to determine the length of different activity phases (high-intensity, low-intensity, and referee pause) and the frequency of techniques. Hormones, glucose, [La], HR, and RPE increased (all P < .001) precombat to postcombat, while a decrease was observed for CMJ, Wingate test performance, body mass (all P < .001), and time of high-intensity activities (P = .005). There was no difference between winners and losers for hormonal, physiological, and physical variables (P > .05). However, winners executed more jab cross, total punches, roundhouse kicks, total kicks, and total attacking techniques (all P < .042) than losers. Kickboxing is an intermittent physically demanding sport that induces changes in the stress-related hormones soliciting the anaerobic lactic system. Training should be oriented to enhance kickboxers' anaerobic lactic fitness and their ability to strike at a sufficient rate. Further investigation is needed to identify possible differences in tactical and mental abilities that offer some insight into what makes winners winners.

  10. Testosterone across successive competitions: evidence for a 'winner effect' in humans?

    PubMed

    Zilioli, Samuele; Watson, Neil V

    2014-09-01

    In many species testosterone fluctuates in concert with outcome-dependent changes in social status, such that winning a competition leads to an increase in circulating testosterone (i.e., competition effect). Although this phenomenon has been well studied in humans, the cumulative endocrine impact of multiple successive competitions is poorly understood. Moreover, although changes in testosterone after a competition seem to predict immediate aggressive behavior, competitive motivation, risk-taking, and affiliation, whether this endocrine response also has long-term behavioral effects, as suggested by studies in non-human animals, has not been examined. In this study, salivary testosterone was collected from pairs of male participants engaging, on two consecutive days, in head-to-head competitions on a previously validated laboratory task. We found that testosterone reactivity on the first day, which was congruent with the competition effect (i.e., net testosterone increase in randomly assigned winners), predicted the task performance on the second day. Further, when looking at testosterone reactivity on the second day, those individuals that lost both competitions experienced the steepest decline in testosterone compared to those individuals who lost on the second day but won on the first day. Testosterone fluctuations on the second day were also analyzed considering the type of status hierarchy (stable vs. unstable) that emerged as a result of the combined outcomes of the two competitions. In accordance with the challenge hypothesis, men in unstable hierarchies (first day winners/second day losers and first day losers/second day winners) experienced an increase in testosterone compared to men in the stable hierarchies (double winners and double losers). Results are discussed within a comparative perspective, drawing parallels with the winner effect and the challenge hypothesis observed in non-human animals.

  11. Lord Rutherford of Nelson, his 1908 Nobel Prize in Chemistry, and why he didn't get a second prize

    NASA Astrophysics Data System (ADS)

    Jarlskog, Cecilia

    2008-11-01

    'I have dealt with many different transformations with various periods of time, but the quickest that I have met was my own transformation in one moment from a physicist to a chemist.' Ernest Rutherford (Nobel Banquet, 1908) This article is about how Ernest Rutherford (1871-1937) got the 1908 Nobel Prize in Chemistry and why he did not get a second Prize for his subsequent outstanding discoveries in physics, specially the discovery of the atomic nucleus and the proton. Who were those who nominated him and who did he nominate for the Nobel Prizes? In order to put the Prize issue into its proper context, I will briefly describe Rutherford's whereabouts. Rutherford, an exceptionally gifted scientist who revolutionized chemistry and physics, was moulded in the finest classical tradition. What were his opinions on some scientific issues such as Einstein's photon, uncertainty relations and the future prospects for atomic energy? What would he have said about the 'Theory of Everything'? Extended version of an invited talk presented at the conference 'Neutrino 2008', Christchurch, NZ, 25-31 May 2008

  12. Positron emission tomography: An overview

    PubMed Central

    Shukla, A. K.; Kumar, Utham

    2006-01-01

    The rate of glucose utilization in tumor cells is significantly enhanced as compared to normal cells and this biochemical characteristic is utilized in PET imaging using FDG as a major workhorse. The PET systems as well as cyclotrons producing positron emitting radiopharmaceuticals have undergone continuous technological refinements. While PET (CT) systems enable fusion images as well as precise attenuation correction, the self-shielded cyclotrons developed provide dedicated systems for in-house production of a large number of PET radiopharmaceuticals. The application of PET images in oncology includes those of pulmonary, colorectal, breast, lymphoma, head & neck, bone, ovarian and GI cancers. The PET has been recognized as promising diagnostic tool to predict biological and physiological changes at the molecular level and hence offer a potential area for future applications including Stem Cell research. PMID:21206635

  13. Positron emission tomography wrist detector

    DOEpatents

    Schlyer, David J.; O'Connor, Paul; Woody, Craig; Junnarkar, Sachin Shrirang; Radeka, Veljko; Vaska, Paul; Pratte, Jean-Francois

    2006-08-15

    A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal representing a time-of-occurrence of an annihilation event, generating an address signal representing a channel detecting the annihilation event, and generating a channel signal including the time and address signals. The method also includes generating a composite signal including the channel signal and another similarly generated channel signal concerning another annihilation event. An apparatus that serially transfers annihilation information includes a time signal generator, address signal generator, channel signal generator, and composite signal generator. The time signal is asynchronous and the address signal is synchronous to a clock signal. A PET scanner includes a scintillation array, detection array, front-end array, and a serial encoder. The serial encoders include the time signal generator, address signal generator, channel signal generator, and composite signal generator.

  14. De-identification Methods for Open Health Data: The Case of the Heritage Health Prize Claims Dataset

    PubMed Central

    Arbuckle, Luk; Koru, Gunes; Eze, Benjamin; Gaudette, Lisa; Neri, Emilio; Rose, Sean; Howard, Jeremy; Gluck, Jonathan

    2012-01-01

    Background There are many benefits to open datasets. However, privacy concerns have hampered the widespread creation of open health data. There is a dearth of documented methods and case studies for the creation of public-use health data. We describe a new methodology for creating a longitudinal public health dataset in the context of the Heritage Health Prize (HHP). The HHP is a global data mining competition to predict, by using claims data, the number of days patients will be hospitalized in a subsequent year. The winner will be the team or individual with the most accurate model past a threshold accuracy, and will receive a US $3 million cash prize. HHP began on April 4, 2011, and ends on April 3, 2013. Objective To de-identify the claims data used in the HHP competition and ensure that it meets the requirements in the US Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule. Methods We defined a threshold risk consistent with the HIPAA Privacy Rule Safe Harbor standard for disclosing the competition dataset. Three plausible re-identification attacks that can be executed on these data were identified. For each attack the re-identification probability was evaluated. If it was deemed too high then a new de-identification algorithm was applied to reduce the risk to an acceptable level. We performed an actual evaluation of re-identification risk using simulated attacks and matching experiments to confirm the results of the de-identification and to test sensitivity to assumptions. The main metric used to evaluate re-identification risk was the probability that a record in the HHP data can be re-identified given an attempted attack. Results An evaluation of the de-identified dataset estimated that the probability of re-identifying an individual was .0084, below the .05 probability threshold specified for the competition. The risk was robust to violations of our initial assumptions. Conclusions It was possible to ensure that the probability of re

  15. Multimode vibrational couplings in resonant positron annihilation.

    PubMed

    d'A Sanchez, Sergio; Lima, Marco A P; Varella, Márcio T do N

    2011-09-02

    The mechanisms for multimode vibrational couplings in resonant positron annihilation are not well understood. We show that these resonances can arise from positron-induced distortions of the potential energy surface (target response to the positron field). Though these distortions can transfer energy into single- and multiquantum vibrations, they have so far been disregarded as a pathway to resonant annihilation. We also compare the existing annihilation theories and show that the currently accepted model can be cast as a special case of the Feshbach annihilation theory.

  16. Prototyping of the ILC Baseline Positron Target

    SciTech Connect

    Gronberg, J; Brooksby, C; Piggott, T; Abbott, R; Javedani, J; Cook, E

    2012-02-29

    The ILC positron system uses novel helical undulators to create a powerful photon beam from the main electron beam. This beam is passed through a titanium target to convert it into electron-positron pairs. The target is constructed as a 1 m diameter wheel spinning at 2000 RPM to smear the 1 ms ILC pulse train over 10 cm. A pulsed flux concentrating magnet is used to increase the positron capture efficiency. It is cooled to liquid nitrogen temperatures to maximize the flatness of the magnetic field over the 1 ms ILC pulse train. We report on prototyping effort on this system.

  17. The Buffer-Gas Positron Accumulator and Resonances in Positron-Molecule Interactions

    NASA Technical Reports Server (NTRS)

    Surko, C.M.

    2007-01-01

    This is a personal account of the development of our buffer-gas positron trap and the new generation of cold beams that these traps enabled. Dick Drachman provided much appreciated advice to us from the time we started the project. The physics underlying trap operation is related to resonances (or apparent resonances) in positron-molecule interactions. Amusingly, experiments enabled by the trap allowed us to understand these processes. The positron-resonance "box score" to date is one resounding "yes," namely vibrational Feshbach resonances in positron annihilation on hydrocarbons; a "probably" for positron-impact electronic excitation of CO and NZ;an d a "maybe" for vibrational excitation of selected molecules. Two of these processes enabled the efficient operation of the trap, and one almost killed it in infancy. We conclude with a brief overview of further applications of the trapping technology discussed here, such as "massive" positron storage and beams with meV energy resolution.

  18. Positron annihilation spectroscopy on a beam of positrons the LEPTA facility

    NASA Astrophysics Data System (ADS)

    Ahmanova, E. V.; Eseev, M. K.; Kobets, A. G.; Meshkov, I. N.; Orlov, O. S.; Sidorin, A. A.; Siemek, K.; Horodek, P.

    2016-12-01

    The results and possibilities of the samples surfaces research by the Doppler method of positron annihilation spectroscopy (PAS) for a monochromatic beam of positrons at the LEPTA facility are presented in this paper. Method with high-resolution sensitivity to defects like vacancies and dislocations allows scanning of the surface and near-surface sample layers to a depth of several micrometers by the method of Doppler broadening of annihilation lines. The opportunities for the development of a PAS method based on the measurement of the positron lifetime in the sample irradiated by ordered flow of positrons from the injector of accelerator complex LEPTA at JINR are discussed.

  19. Bulk Materials Analysis Using High-Energy Positron Beams

    SciTech Connect

    Glade, S C; Asoka-Kumar, P; Nieh, T G; Sterne, P A; Wirth, B D; Dauskardt, R H; Flores, K M; Suh, D; Odette, G R

    2002-11-11

    This article reviews some recent materials analysis results using high-energy positron beams at Lawrence Livermore National Laboratory. We are combining positron lifetime and orbital electron momentum spectroscopic methods to provide electron number densities and electron momentum distributions around positron annihilation sites. Topics covered include: correlation of positron annihilation characteristics with structural and mechanical properties of bulk metallic glasses, compositional studies of embrittling features in nuclear reactor pressure vessel steel, pore characterization in Zeolites, and positron annihilation characteristics in alkali halides.

  20. Method of processing positron lifetime spectra

    SciTech Connect

    Valuev, N.P.; Klimov, A.B.; Zhikharev, A.N.

    1985-05-01

    This paper describes a method for the processing of spectra of positron annihilation which permits a much more relaible determination of the lifetime during numerical processing of spectra by computer.

  1. Positron kinetics in an idealized PET environment

    NASA Astrophysics Data System (ADS)

    Robson, R. E.; Brunger, M. J.; Buckman, S. J.; Garcia, G.; Petrović, Z. Lj.; White, R. D.

    2015-08-01

    The kinetic theory of non-relativistic positrons in an idealized positron emission tomography PET environment is developed by solving the Boltzmann equation, allowing for coherent and incoherent elastic, inelastic, ionizing and annihilating collisions through positronium formation. An analytic expression is obtained for the positronium formation rate, as a function of distance from a spherical source, in terms of the solutions of the general kinetic eigenvalue problem. Numerical estimates of the positron range - a fundamental limitation on the accuracy of PET, are given for positrons in a model of liquid water, a surrogate for human tissue. Comparisons are made with the ‘gas-phase’ assumption used in current models in which coherent scattering is suppressed. Our results show that this assumption leads to an error of the order of a factor of approximately 2, emphasizing the need to accurately account for the structure of the medium in PET simulations.

  2. Addiction Studies with Positron Emission Tomography

    ScienceCinema

    Joanna Fowler

    2016-07-12

    Brookhaven scientist Joanna Fowler describes Positron Emission Technology (PET) research at BNL which for the past 30 years has focused in the integration of basic research in radiotracer chemistry with the tools of neuroscience to develop new scientific

  3. Addiction Studies with Positron Emission Tomography

    SciTech Connect

    Joanna Fowler

    2008-10-13

    Brookhaven scientist Joanna Fowler describes Positron Emission Technology (PET) research at BNL which for the past 30 years has focused in the integration of basic research in radiotracer chemistry with the tools of neuroscience to develop new scientific

  4. Electric charges of positrons and antiprotons

    SciTech Connect

    Hughes, R.J. ); Deutch, B.I. )

    1992-07-27

    Tests of the electric charges carried by the positron and antiproton are derived from recent measurements of the cyclotron frequencies of these particles, and from the spectroscopy of exotic atoms in which they are constituents.

  5. Electron and positron induced processes. POSMOL 2013

    NASA Astrophysics Data System (ADS)

    Limão-Vieira, Paulo; Campeanu, Radu; Hoshino, Masamitsu; Ingólfsson, Oddur; Mason, Nigel; Nagashima, Yasuyuki; Tanuma, Hajime

    2014-09-01

    POSMOL 2013, the international meeting on electron and positron induced processes comprising the XVII International Workshop on Low-Energy Positron and Positronium Physics and the XVIII International Symposium on Electron-Molecule Collisions and Swarms, was held at Kanazawa Bunka Hall, Kanazawa, Ishikawa, Japan, from 19-21 July 2013. The XVII Workshop encompassed all aspects of positron, positronium and antiproton interactions with electrons, atoms, molecules and solid surfaces, and topics related to these, whereas the XVIII Symposium encompassed all aspects of electron interactions with molecules in both gaseous and condensed phases. Particular topics include studies of electron interactions with biomolecules, electron induced surface chemistry and the study of plasma processes. Recent research on the study of electron swarms was also highlighted. Contribution to the Topical Issue "Electron and Positron Induced Processes", edited by Michael Brunger, Radu Campeanu, Masamitsu Hoshino, Oddur Ingólfsson, Paulo Limão-Vieira, Nigel Mason, Yasuyuki Nagashima and Hajime Tanuma.

  6. Hierarchical winner-take-all particle swarm optimization social network for neural model fitting.

    PubMed

    Coventry, Brandon S; Parthasarathy, Aravindakshan; Sommer, Alexandra L; Bartlett, Edward L

    2017-02-01

    Particle swarm optimization (PSO) has gained widespread use as a general mathematical programming paradigm and seen use in a wide variety of optimization and machine learning problems. In this work, we introduce a new variant on the PSO social network and apply this method to the inverse problem of input parameter selection from recorded auditory neuron tuning curves. The topology of a PSO social network is a major contributor to optimization success. Here we propose a new social network which draws influence from winner-take-all coding found in visual cortical neurons. We show that the winner-take-all network performs exceptionally well on optimization problems with greater than 5 dimensions and runs at a lower iteration count as compared to other PSO topologies. Finally we show that this variant of PSO is able to recreate auditory frequency tuning curves and modulation transfer functions, making it a potentially useful tool for computational neuroscience models.

  7. Biased Random-Key Genetic Algorithms for the Winner Determination Problem in Combinatorial Auctions.

    PubMed

    de Andrade, Carlos Eduardo; Toso, Rodrigo Franco; Resende, Mauricio G C; Miyazawa, Flávio Keidi

    2015-01-01

    In this paper we address the problem of picking a subset of bids in a general combinatorial auction so as to maximize the overall profit using the first-price model. This winner determination problem assumes that a single bidding round is held to determine both the winners and prices to be paid. We introduce six variants of biased random-key genetic algorithms for this problem. Three of them use a novel initialization technique that makes use of solutions of intermediate linear programming relaxations of an exact mixed integer linear programming model as initial chromosomes of the population. An experimental evaluation compares the effectiveness of the proposed algorithms with the standard mixed linear integer programming formulation, a specialized exact algorithm, and the best-performing heuristics proposed for this problem. The proposed algorithms are competitive and offer strong results, mainly for large-scale auctions.

  8. Forecasting a winner for Malaysian Cup 2013 using soccer simulation model

    NASA Astrophysics Data System (ADS)

    Yusof, Muhammad Mat; Fauzee, Mohd Soffian Omar; Latif, Rozita Abdul

    2014-07-01

    This paper investigates through soccer simulation the calculation of the probability for each team winning Malaysia Cup 2013. Our methodology used here is we predict the outcomes of individual matches and then we simulate the Malaysia Cup 2013 tournament 5000 times. As match outcomes are always a matter of uncertainty, statistical model, in particular a double Poisson model is used to predict the number of goals scored and conceded for each team. Maximum likelihood estimation is use to measure the attacking strength and defensive weakness for each team. Based on our simulation result, LionXII has a higher probability in becoming the winner, followed by Selangor, ATM, JDT and Kelantan. Meanwhile, T-Team, Negeri Sembilan and Felda United have lower probabilities to win Malaysia Cup 2013. In summary, we find that the probability for each team becominga winner is small, indicating that the level of competitive balance in Malaysia Cup 2013 is quite high.

  9. Do OSCAR winners live longer than less successful peers? A reanalysis of the evidence.

    PubMed

    Sylvestre, Marie-Pierre; Huszti, Ella; Hanley, James A

    2006-09-05

    In an article published in Annals of Internal Medicine in 2001, Redelmeier and Singh reported that Academy Award-winning actors and actresses lived almost 4 years longer than their less successful peers. However, the statistical method used to derive this statistically significant difference gave winners an unfair advantage because it credited an Oscar winner's years of life before winning toward survival subsequent to winning. When the authors of the current article reanalyzed the data using methods that avoided this "immortal time" bias, the survival advantage was closer to 1 year and was not statistically significant. The type of bias in Redelmeier and Singh's study is not limited to longevity comparisons of persons who reach different ranks within their profession; it can, and often does, occur in nonexperimental studies of life- or time-extending benefits of medical interventions. The current authors suggest ways in which researchers and readers may avoid and recognize this bias.

  10. The American Orthodontics BOS MOrth Cases Prize 2005.

    PubMed

    Houghton, Nadine

    2008-06-01

    This paper describes the orthodontic treatment of two cases that were successfully entered for the 2005 American Orthodontics MOrth Cases Prize. The first case is that of a patient presenting with a Class II division 2 malocclusion treated with upper and lower fixed appliances plus headgear. The second case demonstrates the use of a twin-block appliance, followed by fixed appliances to correct a moderate Class II division 1 malocclusion.

  11. Positron annihilation induced Auger electron emission

    SciTech Connect

    Weiss, A.; Jibaly, M.; Lei, Chun; Mehl, D.; Mayer, R.; Lynn, K.G.

    1988-01-01

    We report on measurements of Auger electron emission from Cu and Fe due to core hole excitations produced by the removal of core electrons by matter-antimatter annihilation. Estimates are developed of the probability of positrons annihilating with a 3p electron in these materials. Several important advantages of Positron annihilation induced Auger Electron Spectroscopy (PAES) for surface analysis are suggested. 10 refs., 2 figs.

  12. Thermal positron interactions with alkali covered tungsten

    NASA Astrophysics Data System (ADS)

    Yamashita, Takashi; Iida, Shimpei; Terabe, Hiroki; Nagashima, Yasuyuki

    2016-11-01

    The branching ratios of positron reemission, positronium emission, positronium negative ion emission and capture to the surface state for thermalized positrons at polycrystalline tungsten surfaces coated with Na, K and Cs have been measured. The data shows that the ratios depend on the coverage of the alkali-metal coating. The fraction of the emitted positronium increases with the coverage of the coating up to 90%.

  13. Modulation of a quantum positron acoustic wave

    NASA Astrophysics Data System (ADS)

    Amin, M. R.

    2015-09-01

    Amplitude modulation of a positron acoustic wave is considered in a four-component electron-positron plasma in the quantum magnetohydrodynamic regime. The important ingredients of this study are the inclusion of the particle exchange-correlation potential, quantum diffraction effects via the Bohm potential, and dissipative effect due to viscosity in the momentum balance equation of the charged carriers. A modified nonlinear Schrödinger equation is derived for the evolution of the slowly varying amplitude of the quantum positron acoustic wave by employing the standard reductive perturbation technique. Detailed analysis of the linear and nonlinear dispersions of the quantum positron acoustic wave is presented. For a typical parameter range, relevant to some dense astrophysical objects, it is found that the quantum positron acoustic wave is modulationally unstable above a certain critical wavenumber. Effects of the exchange-correlation potential and the Bohm potential in the wave dynamics are also studied. It is found that the quantum effect due to the particle exchange-correlation potential is significant in comparison to the effect due to the Bohm potential for smaller values of the carrier wavenumber. However, for comparatively larger values of the carrier wavenumber, the Bohm potential effect overtakes the effect of the exchange-correlation potential. It is found that the critical wavenumber for the modulation instability depends on the ratio of the equilibrium hot electron number density and the cold positron number density and on the ratio of the equilibrium hot positron number density and the cold positron number density. A numerical result on the growth rate of the modulation instability is also presented.

  14. 2014 Nuclear Fusion Prize Acceptance Speech 2014 Nuclear Fusion Prize Acceptance Speech

    NASA Astrophysics Data System (ADS)

    Snyder, P. B.

    2015-01-01

    It is a great honor to receive the 2014 Nuclear Fusion Prize, here at the 25th IAEA Fusion Energy Conference. On behalf of everyone involved in this work, I would like to thank the IAEA, the Nuclear Fusion journal team, the IOP, and specifically Mitsuru Kikuchi, for their support of this important award. I would also like to acknowledge the many important contributions made by the other ten papers nominated for this prize. Our paper investigates the physics of the H-mode pedestal in tokamaks, specifically the development of a predictive understanding of the pedestal structure based on electromagnetic instabilities which constrain it, and the testing of the resulting theoretical model (EPED) against detailed observations on multiple devices. In addition to making pedestal predictions for existing devices, the paper also presents predictions for ITER, including methods for optimizing its pedestal height and fusion performance. What made this work possible, and indeed a pleasure to be involved with, was an extensive set of collaborations, including theory-experiment, multi-institutional, and international collaborations. Many of these collaborations have gone on for over a decade, and have been fostered in part by the ITPA Pedestal Group. The eight authors of this paper, from five institutions, all made important contributions. Rich Groebner, Tom Osborne and Tony Leonard carried out dedicated experiments and data analysis on the DIII-D tokamak, testing the EPED model over a very wide range of parameters. Jerry Hughes led dedicated experiments on Alcator C-Mod which tested the model at high magnetic field and pedestal pressure. Marc Beurskens carried out experiments and data analysis on the JET tokamak, testing the model at large scale. Xueqiao Xu conducted two-fluid studies of diamagnetic stabilization, which enabled a more accurate treatment of this important effect. Finally, Howard Wilson and I have been working together for many years to develop analytic formalism

  15. Kevin E. Trenberth Receives 2013 Climate Communication Prize: Response

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.

    2014-01-01

    I am delighted to be recognized with this prize. I want to first thank AGU and the prize committee and, especially, Nature's Own for establishing this prize in a field that has become contentious and highly political. It did not used to be this way. Following the media frenzy with the 2007 Intergovernmental Panel on Climate Change (IPCC) report, there was hope at the 2009 Conference of Parties meeting in Copenhagen that an international framework agreement on climate change might be achieved. It was not to be. Planned actions to address issues of climate change were undermined by huge funding of misinformation by vested interests. It was not helped by so-called "climategate" in which many emails illegally hacked from a computer server at the University of East Anglia in the United Kingdom were released, cherry picked, distorted, and misused by climate change deniers. Minor errors in the IPCC report were blown out of all proportion and ineffectively addressed. I was caught up in all this, and one of my many emails went viral: the "travesty" quote in which I bemoaned the inability to close the global energy balance associated with short-term climate variability but which was misinterpreted as saying there was no global warming. These examples highlight failures of communication.

  16. "Highly qualified loser"? Harvey Cushing and the Nobel Prize.

    PubMed

    Hansson, Nils; Schlich, Thomas

    2015-04-01

    Neurosurgery, in particular surgery of the brain, was recognized as one of the most spectacular transgressions of the traditional limits of surgical work. With their audacious, technically demanding, laboratory-based, and highly promising new interventions, prominent neurosurgeons were primary candidates for the Nobel Prize. Accordingly, neurosurgical pioneers such as Victor Horsley and, in particular, Harvey Cushing continued to be nominated for the prize. However, only António Egas Moniz was eventually awarded the prestigious award in 1949 for the introduction of frontal lobotomy, an intervention that would no longer be prize-worthy from today's perspective. Horsley and Cushing, who were arguably the most important proponents of early neurosurgery, remained "highly qualified losers," as such cases have been called. This paper examines the nominations, reviews, and discussions kept in the Nobel Archives to understand the reasons for this remarkable choice. At a more general level, the authors use the example of neurosurgery to explore the mechanisms of scientific recognition and what could be called the enacting of excellence in science and medicine.

  17. Positron annihilation studies of organic superconductivity

    SciTech Connect

    Yen, H.L.; Lou, Y.; Ali, E.H.

    1994-09-01

    The positron lifetimes of two organic superconductors, {kappa}-(ET){sub 2}Cu(NCS){sub 2} and {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br, are measured as a function of temperature across {Tc}. A drop of positron lifetime below {Tc} is observed. Positron-electron momentum densities are measured by using 2D-ACAR to search for the Fermi surface in {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br. Positron density distributions and positron-electron overlaps are calculated by using the orthogonalized linear combination atomic orbital (OLCAO) method to interprete the temperature dependence due to the local charge transfer which is inferred to relate to the superconducting transition. 2D-ACAR results in {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br are compared with theoretical band calculations based on a first-principles local density approximation. Importance of performing accurate band calculations for the interpretation of positron annihilation data is emphasized.

  18. Recognizing 21. century citizenship: 1997 federal energy and water management award winners

    SciTech Connect

    1997-12-31

    Energy is a luxury that no one can afford to waste, and many Federal government agencies are becoming increasingly aware of the importance of using energy wisely. Thoughtful use of energy resources is important, not only to meet agency goals, but because energy efficiency helps improve air quality. Sound facility management offers huge savings that affect the agency`s bottom line, the environment, and workplace quality. Hard work, innovation, and vision are characteristic of those who pursue energy efficiency. That is why the Department of Energy, Federal Energy Management Program (FEMP) is proud to salute the winners of the 1997 Federal Energy and Water Management Award. The 1997 winners represent the kind of 21st century thinking that will help achieve widespread Federal energy efficiency. In one year, the winners, through a combination of public and private partnerships, saved more than $100 million and 9.8 trillion Btu by actively identifying and implementing energy efficiency, water conservation, and renewable energy projects. The contributions of these individuals, small groups, and organizations are presented in this report.

  19. The Role of Awards Programs in Stimulating Energy Efficient Behavior: A Study of Award Winners

    SciTech Connect

    McDermott, Christa; Malone, Elizabeth L.

    2014-07-01

    The value of formal awards programs may be principally in gaining wider recognition for achievements in energy efficiency. But how do these programs contribute to the goal that is presumably behind this value, i.e., stimulating further energy efficient behavior, beyond publicizing the awards ceremonies and describing the projects via websites, posters, and the like? Interviews with 22 individuals and teams of award winners under the Department of Energy Federal Energy Management Program (DOE FEMP) yield insights on the roles that awards programs can play in stimulating energy efficient behavior, especially with regard to institutional dimensions of such behavior. Award winners identified institutional facilitators and barriers in their projects and programs as well as factors in their implementation processes, thus providing information that can guide other efforts. Although only one of the interviewees affirmed that winning an award was a motivating factor, awards do validate often-hard-won achievements through recognition and, in some cases, additional resources, thus stimulating both the winners themselves and those who see the achievements to further energy-saving activities. Finally, award winners’ responses demonstrated the importance of behavioral and institutional change in energy efficiency.

  20. Imitating winner or sympathizing loser? Quadratic effects on cooperative behavior in prisoners' dilemma games

    NASA Astrophysics Data System (ADS)

    Lu, Peng

    2015-10-01

    Cooperation is vital in human societies and therefore is widely investigated in the evolutionary game theory. Varieties of mechanisms have been proposed to overcome temptation and promote cooperation. Existing studies usually believe that agents are rational, but irrationalism such as emotions and feelings matters as well. Winner and loser are defined by their payoffs. In addition to admiring and imitating winners, the mechanism of sympathizing and imitating losers is introduced into the model as an alternative action rule, and each one plays the prisoners' dilemma game with eight neighbors under the influence of both irrationalism and rationalism. Rationalism refers to imitating winner to get highest payoff, and irrationalism means that people sympathize and adopt the actions of losers. As it is widely recognized that temptation reduces cooperation, this study focuses on the effect of sympathy on cooperation within a certain group or society. If it overcomes temptation that leads to defection, sympathy will be a powerful mechanism to promote cooperative behavior. Simulation results indicate that sympathy and temptation shares similar quadratic relationships with cooperation. Both sympathy and temptation undermine cooperation below their thresholds, and they both promote cooperation above their thresholds. Temptation not only reduces cooperation but also promote it as temptation goes beyond the threshold. Although sympathy is a good merit or human nature that is beneficial to society, a crisis or collapse of cooperation is inevitable when the sympathy propensity is relatively smaller. After cooperation reaches a minimal bottom, it then rises increasingly and dramatically, which brings a much brighter future of the society.

  1. Learning your own strength: winner and loser effects should change with age and experience

    PubMed Central

    Fawcett, Tim W.; Johnstone, Rufus A.

    2010-01-01

    Winner and loser effects, in which the outcome of an aggressive encounter influences the tendency to escalate future conflicts, have been documented in many taxa, but we have limited understanding of why they have evolved. One possibility is that individuals use previous victories and defeats to assess their fighting ability relative to others. We explored this idea by modelling a population of strong and weak individuals that do not know their own strength, but keep track of how many fights they have won. Under these conditions, adaptive behaviour generates clear winner and loser effects: individuals who win fights should escalate subsequent conflicts, whereas those who lose should retreat from aggressive opponents. But these effects depend strongly on age and experience. Young, naive individuals should show highly aggressive behaviour and pronounced loser effects. For these inexperienced individuals, fighting is especially profitable because it yields valuable information about their strength. Aggression should then decline as an individual ages and gains experience, with those who lose fights becoming more submissive. Older individuals, who have a better idea of their own strength, should be more strongly influenced by victories than losses. In conclusion, we predict that both aggressiveness and the relative magnitude of winner and loser effects should change with age, owing to changes in how individuals perceive their own strength. PMID:20053644

  2. Intense low energy positron beams

    SciTech Connect

    Lynn, K.G.; Jacobsen, F.M.

    1993-12-31

    Intense positron beams are under development or being considered at several laboratories. Already today a few accelerator based high intensity, low brightness e{sup +} beams exist producing of the order of 10{sup 8} {minus} 10{sup 9} e{sup +}/sec. Several laboratories are aiming at high intensity, high brightness e{sup +} beams with intensities greater than 10{sup 9} e{sup +}/sec and current densities of the order of 10{sup 13} {minus} 10{sup 14} e{sup +} sec{sup {minus}} {sup 1}cm{sup {minus}2}. Intense e{sup +} beams can be realized in two ways (or in a combination thereof) either through a development of more efficient B{sup +} moderators or by increasing the available activity of B{sup +} particles. In this review we shall mainly concentrate on the latter approach. In atomic physics the main trust for these developments is to be able to measure differential and high energy cross-sections in e{sup +} collisions with atoms and molecules. Within solid state physics high intensity, high brightness e{sup +} beams are in demand in areas such as the re-emission e{sup +} microscope, two dimensional angular correlation of annihilation radiation, low energy e{sup +} diffraction and other fields. Intense e{sup +} beams are also important for the development of positronium beams, as well as exotic experiments such as Bose condensation and Ps liquid studies.

  3. Dynamics of the positron acoustic waves in electron-positron-ion magnetoplasmas

    NASA Astrophysics Data System (ADS)

    Ali, Rustam; Saha, Asit; Chatterjee, Prasanta

    2017-01-01

    Dynamics of the positron acoustic waves in electron-positron-ion (e-p-i) magnetoplasmas with κ-distributed hot electrons and positrons is investigated in the frameworks of the Kadomtsev-Petviashili (KP) and modified Kadomtsev-Petviashili (mKP) equations. Employing the reductive perturbation technique, the KP and mKP equations are derived. Using the bifurcation theory of planar dynamical systems, the positron acoustic solitary wave solutions, the kink and anti-kink wave solutions are obtained. Considering an external periodic perturbation in the electron-positron-ion magnetoplasmas, the perturbed KP and mKP equations are studied via some qualitative and quantitative approaches. To corroborate in the fact that the perturbed KP and mKP equations can indeed give rise to the quasiperiodic and chaotic motions, the phase plane plots, time series plots, and the Poincaré section are used. The quasiperiodic and developed chaos can be observed for the perturbed positron acoustic waves. The frequency (ω ) of the external periodic perturbation plays the role of the switching parameter in chaotic motions of the perturbed positron acoustic waves through quasiperiodic route to chaos. This work can be useful to understand the dynamics of nonlinear electromagnetic perturbations in space and laboratory plasmas consisting of κ-distributed hot electrons and positrons.

  4. Van de Graaff based positron source production

    NASA Astrophysics Data System (ADS)

    Lund, Kasey Roy

    The anti-matter counterpart to the electron, the positron, can be used for a myriad of different scientific research projects to include materials research, energy storage, and deep space flight propulsion. Currently there is a demand for large numbers of positrons to aid in these mentioned research projects. There are different methods of producing and harvesting positrons but all require radioactive sources or large facilities. Positron beams produced by relatively small accelerators are attractive because they are easily shut down, and small accelerators are readily available. A 4MV Van de Graaff accelerator was used to induce the nuclear reaction 12C(d,n)13N in order to produce an intense beam of positrons. 13N is an isotope of nitrogen that decays with a 10 minute half life into 13C, a positron, and an electron neutrino. This radioactive gas is frozen onto a cryogenic freezer where it is then channeled to form an antimatter beam. The beam is then guided using axial magnetic fields into a superconducting magnet with a field strength up to 7 Tesla where it will be stored in a newly designed Micro-Penning-Malmberg trap. Several source geometries have been experimented on and found that a maximum antimatter beam with a positron flux of greater than 0.55x10 6 e+s-1 was achieved. This beam was produced using a solid rare gas moderator composed of krypton. Due to geometric restrictions on this set up, only 0.1-1.0% of the antimatter was being frozen to the desired locations. Simulations and preliminary experiments suggest that a new geometry, currently under testing, will produce a beam of 107 e+s-1 or more.

  5. Elastic and inelastic scattering of positrons in gases and solids

    NASA Technical Reports Server (NTRS)

    Mcgowan, J. W.

    1972-01-01

    Three apparatuses were designed and built: The first, which is now operative, was designed to study the details of positron thermalization in solids and the subsequent emission of the low energy positrons from moderating foils; The second apparatus now under test is a positron bottle similar in design to an electron trap. It was built to store positrons at a fixed energy and to look at the number of stored positrons (storage time) as a function of a scattering gas in the vacuum chamber. The third apparatus is a crossed beam apparatus where positron-, alkali scattering will be studied. Much of the apparatus is now under test with electrons.

  6. Electron capture from solids by positrons

    SciTech Connect

    Howell, R.

    1987-08-01

    The capture of electrons in solids is modified from that in gasses by several factors. The most important is the collective interaction of the electrons which results in a density of electron states in the solid in wide bands. Also the high density of electrons in many solids gives a high frequency of interaction as compared to gasses, and quickly destroys any electron-positron states in the metal matrix. Consequently, most positrons implanted in a metal will rapidly thermalize, and unless they reach the surface will annihilate with an electron in an uncorrelated state. Positronium formation from positrons scattered at a metal surface is analogous to ion neutralization however, most of the positronium comes from positrons passing through the surface from the bulk. The dominant motivation for studying positronium formation has been the hope that the distribution of the electrons at the surface would be obtained through the annihilation properties of positrons trapped at the surface or through analysis of the energy and angular distributions of the positronium emitted into the vacuum. These distributions have been measured and are included in this paper. 17 refs.

  7. 77 FR 58114 - SunShot Prize: Race to the Rooftop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-19

    ... installation cost of rooftop solar energy systems. DATES: Registration opened on September 12, 2012, and will... about the SunShot Prize: Race to the Rooftop competition rules at eere.energy.gov/solar/sunshot/prize.html . Teams that wish to enter the competition can register at...

  8. The History of Molecular Structure Determination Viewed through the Nobel Prizes.

    ERIC Educational Resources Information Center

    Jensen, William P.; Palenik, Gus J.; Suh, Il-Hwan

    2003-01-01

    Discusses the importance of complex molecular structures. Emphasizes their individual significance through examination of the Nobel Prizes of the 20th century. Highlights prizes awarded to Conrad Rontgen, Francis H.C. Crick, James D. Watson, Maurice H.F. Wilkins, and others. (SOE)

  9. 45 CFR 73.735-505 - Acceptance of awards and prizes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Acceptance of awards and prizes. 73.735-505 Section 73.735-505 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION STANDARDS OF CONDUCT Gifts, Entertainment, and Favors § 73.735-505 Acceptance of awards and prizes. (a) Employees may accept awards, including cash...

  10. Collecting Poetry for the Academic Library: An Evaluation of Poetry Prizes as Selection Tools

    ERIC Educational Resources Information Center

    Golomb, Liorah

    2011-01-01

    This paper examines the usefulness of poetry book prizes as a selection tool by evaluating their fairness, meaningfulness, and reliability as an indication of quality. The results of two surveys, one collecting data on poetry book prizes and the other asking librarians about their collecting practices, suggest that selecting on the basis of prizes…

  11. Vouchers Versus Prizes: Contingency Management Treatment of Substance Abusers in Community Settings

    ERIC Educational Resources Information Center

    Petry, Nancy M.; Alessi, Sheila M.; Marx, Jacqueline; Austin, Mark; Tardif, Michelle

    2005-01-01

    Contingency management (CM) interventions usually use vouchers as reinforcers, but a new technique awards chances of winning prizes. This study compares these approaches. In community treatment centers, 142 cocaine- or heroin-dependent outpatients were randomly assigned to standard treatment (ST), ST with vouchers, or ST with prizes for 12 weeks.…

  12. Unthermalized positrons in gamma ray burst sources

    NASA Technical Reports Server (NTRS)

    Tkaczyk, W.; Karakula, S.

    1992-01-01

    The spectra of the broadening 0.511 MeV annihilation line produced by high temperatures was calculated in the case of unthermalized plasma; i.e., T sub e(+) is not = T sub e(-). The flattening in the spectrum of the annihilation lines for large differences of electron and positron temperatures is a strong indication that the observed features of the hard tailed spectrum of the gamma bursts can be well described by annihilation of unthermalized positrons. It is proposed that the charge separation occurring in Eddington limited accretion onto a neutron star or the one photon pair production in strong magnetic fields as a mechanism for the production of unthermalized positrons in the sources of gamma bursts. From the best fit of experimental spectra by the model, the parameters of sources for which the regions with different plasma temperatures can exist is evaluated.

  13. Positron transport: The plasma-gas interface

    SciTech Connect

    Marler, J. P.; Petrovic, Z. Lj.; Bankovic, A.; Dujko, S.; Suvakov, M.; Malovic, G.; Buckman, S. J.

    2009-05-15

    Motivated by an increasing number of applications, new techniques in the analysis of electron transport have been developed over the past 30 years or so, but similar methods had yet to be applied to positrons. Recently, an in-depth look at positron transport in pure argon gas has been performed using a recently established comprehensive set of cross sections and well-established Monte Carlo simulations. The key novelty as compared to electron transport is the effect of positronium formation which changes the number of particles and has a strong energy dependence. This coupled with spatial separation by energy of the positron swarm leads to counterintuitive behavior of some of the transport coefficients. Finally new results in how the presence of an applied magnetic field affects the transport coefficients are presented.

  14. Defects in metals. [Positron annihilation spectroscopy

    SciTech Connect

    Siegel, R.W.

    1982-06-01

    The application of positron annihilation spectroscopy (PAS) to the study of defects in metals has led to increased knowledge on lattice-defect properties during the past decade in two areas: the determination of atomic defect properties, particularly those of monovacancies, and the monitoring and characterization of vacancy-like microstructure development during post-irradiation and post-quench annealing. The study of defects in metals by PAS is reviewed within the context of the other available techniques for defect studies. The strengths and weaknesses of PAS as a method for the characterization of defect microstructures are considered. The additional possibilities for using the positron as a localized probe of the atomic and electronic structures of atomic defects are discussed, based upon theoretical calculations of the annihilation characteristics of defect-trapped positrons and experimental observations. Finally, the present status and future potential of PAS as a tool for the study of defects in metals is considered. 71 references, 9 figures.

  15. Trapped positrons observed by PAMELA experiment

    NASA Astrophysics Data System (ADS)

    Mikhailov, V. V.; Adriani, O.; Barbarino, G.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F. S.; Campana, D.; Carbone, R.; Carlson, P.; Casolino, M.; Castellini, G.; Consiglio, L.; De Santis, C.; De Simone, N.; Di Felice, V.; Galper, A. M.; Karelin, A. V.; Koldashov, S. V.; Koldobsky, S.; Krutkov, S. Yu; Kvashnin, A. N.; Leonov, A. A.; Malakhov, V. V.; Marcelli, L.; Martucci, M.; Mayorov, A. G.; Menn, W.; Merge, M.; Mocchiutti, E.; Monaco, A.; Mori, N.; Munini, R.; Osteria, G.; Papini, P.; Palma, F.; Panico, B.; Pearce, M.; Picozza, P.; Ricci, M.; Ricciarini, S. B.; Sarkar, R.; Scotti, V.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Yu I.; Vacchi, A.; Vannuccini, E.; Vasiliev, G. I.; Voronov, S. A.; Yurkin, Yu T.; Zampa, G.; Zampa, N.

    2016-02-01

    Measurements of electron and positron spatial distributions in energy range from 80 MeV to several GeV below the geomagnetic cutoff rigidity were carried out using the PAMELA magnetic spectrometer. The instrument is installed on board the Resurs-DK satellite which was launched June 15th 2006 on an elliptical orbit with the inclination 70 degrees and the altitude 350-600 km. The procedure of trajectories calculations in the geomagnetic filed gives a way to separate stably trapped and short lived albedo components produced in interactions of cosmic ray protons with the residual atmosphere. The work presents spatial distributions of trapped, quasitrapped and short-lived albedo electrons and positrons in the near Earth space. Electron to positron ratio points out on different production mechanism of trapped and quasitrapped particles.

  16. Positron annihilation in solid and liquid Ni

    SciTech Connect

    Fluss, M.J.; Smedskjaer, L.C.; Chakraborty, B.; Chason, M.K.

    1982-03-01

    New techniques have been developed for the study of metals via positron annihilation which provide for the in-situ melting of the samples and subsequent measurements via Doppler broadening of positron-annihilation radiation. Here we report these metods currently in use at our laboratory; ion implantation of /sup 58/Co and the use of Al/sub 2/O/sub 3/ crucibles for in-situ melting followed by the decomposition of the Doppler-broadened spectrum into a parabolic and a Gaussian component. Our earliest results obtained for pure Ni in the polycrystalline solid and in the liquid state are compared. An interesting similarity is reported for the distributions of the high-momentum (Gaussian) component for positrons annihilating in vacancies at high temperatures and those annihilating in liquid Ni.

  17. Positron states and annihilation characteristics of surface-trapped positrons at the oxidized Cu(110) surface

    NASA Astrophysics Data System (ADS)

    Fazleev, N. G.; Olenga, Antoine; Weiss, A. H.

    2013-03-01

    The process by which oxide layers are formed on metal surfaces is still not well understood. In this work we present the results of theoretical studies of positron states and annihilation characteristics of surface-trapped positrons at the oxidized Cu(110) surface. An ab-initio investigation of stability and associated electronic properties of different adsorption phases of oxygen on Cu(110) has been performed on the basis of density functional theory and using DMOl3 code. The changes in the positron work function and the surface dipole moment when oxygen atoms occupy on-surface and sub-surface sites have been attributed to charge redistribution within the first two layers, buckling effects within each layer and interlayer expansion. The computed positron binding energy, positron surface state wave function, and annihilation probabilities of surface trapped positrons with relevant core electrons demonstrate their sensitivity to oxygen coverage, elemental content, atomic structure of the topmost layers of surfaces, and charge transfer effects. Theoretical results are compared with experimental data obtained from studies of oxidized transition metal surfaces using positron annihilation induced Auger electron spectroscopy. This work was supported in part by the National Science Foundation Grant DMR-0907679.

  18. Nonlinear excitations for the positron acoustic shock waves in dissipative nonextensive electron-positron-ion plasmas

    NASA Astrophysics Data System (ADS)

    Saha, Asit

    2017-03-01

    Positron acoustic shock waves (PASHWs) in unmagnetized electron-positron-ion (e-p-i) plasmas consisting of mobile cold positrons, immobile positive ions, q-nonextensive distributed electrons, and hot positrons are studied. The cold positron kinematic viscosity is considered and the reductive perturbation technique is used to derive the Burgers equation. Applying traveling wave transformation, the Burgers equation is transformed to a one dimensional dynamical system. All possible vector fields corresponding to the dynamical system are presented. We have analyzed the dynamical system with the help of potential energy, which helps to identify the stability and instability of the equilibrium points. It is found that the viscous force acting on cold mobile positron fluid is a source of dissipation and is responsible for the formation of the PASHWs. Furthermore, fully nonlinear arbitrary amplitude positron acoustic waves are also studied applying the theory of planar dynamical systems. It is also observed that the fundamental features of the small amplitude and arbitrary amplitude PASHWs are significantly affected by the effect of the physical parameters q e , q h , μ e , μ h , σ , η , and U. This work can be useful to understand the qualitative changes in the dynamics of nonlinear small amplitude and fully nonlinear arbitrary amplitude PASHWs in solar wind, ionosphere, lower part of magnetosphere, and auroral acceleration regions.

  19. Position-resolved Positron Annihilation Lifetime Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wagner, A.; Butterling, M.; Fiedler, F.; Fritz, F.; Kempe, M.; Cowan, T. E.

    2013-06-01

    A new method which allows for position-resolved positron lifetime spectroscopy studies in extended volume samples is presented. In addition to the existing technique of in-situ production of positrons inside large (cm3) bulk samples using high-energy photons up to 16 MeV from bremsstrahlung production, granular position-sensitive photon detectors have been employed. A beam of intense bremsstrahlung is provided by the superconducting electron linear accelerator ELBE (Electron Linear Accelerator with high Brilliance and low Emittance) which delivers electron bunches of less than 10 ps temporal width and an adjustable bunch separation of multiples of 38 ns, average beam currents of 1 mA, and energies up to 40 MeV. Since the generation of bremsstrahlung and the transport to the sample preserves the sharp timing of the electron beam, positrons generated inside the entire sample volume by pair production feature a sharp start time stamp for positron annihilation lifetime studies with high timing resolutions and high signal to background ratios due to the coincident detection of two annihilation photons. Two commercially available detectors from a high-resolution medial positron-emission tomography system are being employed with 169 individual Lu2SiO5:Ce scintillation crystals, each. In first experiments, a positron-lifetime gated image of a planar Si/SiO2 (pieces of 12.5 mm × 25 mm size) sample and a 3-D structured metal in Teflon target could be obtained proving the feasibility of a three dimensional lifetime-gated tomographic system.

  20. Monoenergetic positron beam at the reactor based positron source at FRM-II

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, C.; Kögel, G.; Repper, R.; Schreckenbach, K.; Sperr, P.; Straßer, B.; Triftshäuser, W.

    2002-05-01

    The principle of the in-pile positron source at the Munich research reactor FRM-II is based on absorption of high energy prompt γ-rays from thermal neutron capture in 113Cd. For this purpose, a cadmium cap is placed inside the tip of the inclined beam tube SR-11 in the moderator tank of the reactor, where an undisturbed thermal neutron flux up to 2×10 14n cm-2 s-1 is expected. Inside the cadmium cap a structure of platinum foils is placed for converting high energy γ-radiation into positron-electron pairs. Due to the negative positron work function, moderation in annealed platinum leads to emission of monoenergetic positrons. Therefore, platinum will also be used as moderator, since its moderation property seems to yield long-term stability under reactor conditions and it is much easier to handle than tungsten. Model calculations were performed with SIMION-7.0w to optimise geometry and potential of Pt-foils and electrical lenses. It could be shown that the potentials between the Pt-foils must be chosen in the range of 1-10 V to extract moderated positrons. After successive acceleration to 5 keV by four electrical lenses the beam is magnetically guided in a solenoid field of 7.5 mT resulting in a beam diameter of about 25 mm. An intensity of about 10 10 slow positrons per second is expected in the primary positron beam. Outside of the reactor shield a W(1 0 0) single crystal remoderation stage will lead to an improvement of the positron beam brilliance before the positrons are guided to the experimental facilities.

  1. Apparatus for photon activation positron annihilation analysis

    DOEpatents

    Akers, Douglas W.

    2007-06-12

    Non-destructive testing apparatus according to one embodiment of the invention comprises a photon source. The photon source produces photons having predetermined energies and directs the photons toward a specimen being tested. The photons from the photon source result in the creation of positrons within the specimen being tested. A detector positioned adjacent the specimen being tested detects gamma rays produced by annihilation of positrons with electrons. A data processing system operatively associated with the detector produces output data indicative of a lattice characteristic of the specimen being tested.

  2. NLC Positron Target Heating(LCC-0065)

    SciTech Connect

    Schultz, D

    2003-10-07

    The NLC requires an intense beam with a large number of positrons. These positrons are produced by a high energy electron beam impinging on a solid tungsten-rhenium alloy target. The particle shower that develops in the solid target deposits significant energy in the material, leading to target stresses and potentially to target damage. The stresses can be analyzed once the magnitude and extent of the energy deposition is known. This note details the modeling of the energy deposition using EGS, performed for the NLC and the SLC targets and for possible NLC targets made of copper or nickel instead of WRe.

  3. Preferential positron heating and acceleration by synchrotron maser instabilities in relativistic positron-electron-proton plasmas

    NASA Technical Reports Server (NTRS)

    Hoshino, Masahiro; Arons, Jonathan

    1991-01-01

    A new process of the preferential strong heating of positrons through the ion synchrotron maser instability in positron-electron-proton magnetized plasmas is investigated using particle-in-cell simulations. It is shown that the positrons form a nonthermal power-law-like energy distribution via their gyroresonant interaction with the extraordinary modes emitted by the ions. It is noted that this process may be of significance in connection with the shock excitation of nonthermal synchrotron radiation from astrophysical systems powered by relativistic outflows from compact central objects, e.g., supernova remnants powered by pulsars and jets from active galactic nuclei.

  4. Role of vibrational dynamics in resonant positron annihilation on molecules.

    PubMed

    Jones, A C L; Danielson, J R; Natisin, M R; Surko, C M

    2013-05-31

    Vibrational Feshbach resonances are dominant features of positron annihilation for incident positron energies in the range of the molecular vibrations. Studies in relatively small molecules are described that elucidate the role of intramolecular vibrational energy redistribution into near-resonant multimode states, and the subsequent coupling of these modes to the positron continuum, in suppressing or enhancing these resonances. The implications for annihilation in other molecular species, and the necessary ingredients of a more complete theory of resonant positron annihilation, are discussed.

  5. A note on sequential monitoring of select-the-winner design.

    PubMed

    Lan, K K Gordon; Chen, Fei; Zhong, Bob; Shun, Zhenming

    2015-01-01

    Consider a trial comparing two treatments or doses A and B with a control C. Based on a unblinded interim look, a winner W between A and B will be chosen, and future patients will be randomized to W and C and compared at the end of a study. The naïve test statistic Z under this setting follows an approximate normal distribution, as shown by Lan et al. (2006) and Shun et al. (2008). Results of these two articles apply only to the fixed sample size design. With simple modifications, this manuscript extends the previous works to the group sequential setting.

  6. Improved Monkey-King Genetic Algorithm for Solving Large Winner Determination in Combinatorial Auction

    NASA Astrophysics Data System (ADS)

    Li, Yuzhong

    Using GA solve the winner determination problem (WDP) with large bids and items, run under different distribution, because the search space is large, constraint complex and it may easy to produce infeasible solution, would affect the efficiency and quality of algorithm. This paper present improved MKGA, including three operator: preprocessing, insert bid and exchange recombination, and use Monkey-king elite preservation strategy. Experimental results show that improved MKGA is better than SGA in population size and computation. The problem that traditional branch and bound algorithm hard to solve, improved MKGA can solve and achieve better effect.

  7. Positron studies of metal-oxide-semiconductor structures

    SciTech Connect

    Au, H.L.; Asoka-Kumar, P.; Nielsen, B.; Lynn, K.G. )

    1993-03-15

    Positron annihilation spectroscopy provides a new probe to study the properties of interface traps in metal-oxide semiconductors (MOS). Using positrons, we have examined the behavior of the interface traps as a function of gate bias. We propose a simple model to explain the positron annihilation spectra from the interface region of a MOS capacitor.

  8. Physics perspectives at JLab with a polarized positron beam

    SciTech Connect

    Voutier, Eric J.-M.

    2014-06-01

    Polarized positron beams are in some respect mandatory complements to polarized electron beams. The advent of the PEPPo concept for polarized positron production opens the possibility for the developement at the Jefferson Laboratory of a continuous polarized positron beam. The benefits of such a beam for hadronic structure studies are discussed, together with the technical and technological challenges to face.

  9. Positron emission tomography - a new approach to brain chemistry

    SciTech Connect

    Jacobson, H.G.

    1988-11-11

    Positron emission tomography permits examination of the chemistry of the brain in living beings. Until recently, positron emission tomography had been considered a research tool, but it is rapidly moving into clinical practice. This report describes the uses and applications of positron emission tomography in examinations of patients with strokes, epilepsy, malignancies, dementias, and schizophrenia and in basic studies of synaptic neurotransmission.

  10. The multilayer Fe/Hf studied with slow positron beam

    NASA Astrophysics Data System (ADS)

    Murashige, Y.; Tashiro, M.; Nakajyo, T.; Koizumi, T.; Kanazawa, I.; Komori, F.; Ito, Y.

    1997-04-01

    The positron annihilation parameter versus the incident positron energy is measured in the thin Fe films and the Fe/Hf bilayer on silica substrate, by means of the variable energetic slow-positron beam technique. We have analyzed the change in open-volume spaces and vacancy-type defects among the Fe microcrystals in these thin films with the deposition temperature.

  11. Jeffrey T. Kiehl Receives 2012 Climate Communication Prize: Response

    NASA Astrophysics Data System (ADS)

    Kiehl, Jeffrey T.

    2013-01-01

    I thank James Hurrell for his gracious citation of my work on communicating climate science to the public. I am deeply moved by his summary of my work over these past years. It clearly reflects how passionately I feel about this work and how important communication is for our field. I thank the Prize Committee for their recognition of my work and Nature's Own for supporting this important AGU prize. As climate scientists, I feel we have a duty to convey our research to the public in meaningful ways. This is especially true given that much of our scientific research is supported by tax-paying citizens. I also believe there is a moral imperative to communicate our research to the world. Our understanding of the significant climatic changes occurring now and those that will occur in the future places a great burden on all of us as scientists. We cannot hold onto our science like some protected treasure but must convey both the facts and the serious implications of our science to more than just our peers.

  12. APS presents prizes in fluid dynamics and plasma physics

    SciTech Connect

    Not Available

    1992-12-01

    This article reviews the presentation of the American Physical Society awards in fluid dynamics and plasma physics. The recipient of the plasma physics James Clerk Maxwell Prize was John M. Green for contributions to the theory of magnetohydrodynamics equilibria and ideal and resistive instabilities, for discovering the inverse scattering transform leading to soliton solutions of many nonlinear partial differential equations and for inventing the residue method of determining the transition to global chaos. The excellence in Plasma Physics Research Award was presented to Nathaniel A. Fisch for theoretical investigations of noninductive current generation in toroidally confined plasma. Wim Pieter Leemans received the Simon Ramo Award for experimental and simulational contributions to laser-plasma physics. William R. Sears was given the 1992 Fuid Dynamics Prize for contributions to the study of steady and unsteady aerodynamics, aeroacoustics, magnetoaerodynamics,and wind tunnel design. William C. Reynolds received the Otto Laporte Award for experimental, theoretical, and computational work in turbulence modeling and control and leadership in direct numerical simulation and large eddy simulation.

  13. [Weizsäcker, Bethe and the Nobel Prize].

    PubMed

    Schaaf, Michael

    2014-01-01

    For his work on nuclear physics Carl Friedrich von Weizsäcker was twice nominated for the Nobel Prize in physics. Bethe had worked on the energy production in stars at about the same time as Weizsäcker but independently from him. The Nobel Committee valued the structural depth of BETHE'S work more than Weizsäcker's temporal priority because Bethe had described the nuclear reactions quantitatively and had shown a much deeper understanding of the nuclear processes in the centre of stars whereas Weizsäcker had worked more qualitatively. There are no reasons to believe that political resentments towards Weizsäcker played any significant role in awarding of the Nobel Prize in Physics in 1967 only to Bethe. The lives and works of Weizsäcker and Bethe show some remarkable parallels, ranging from calculating the binding energy in nuclei to the energy production in sun-like and massive stars to peace- and disarmament initiatives.

  14. Leon Van Speybroeck Wins Astrophysics Bruno Rossi Prize

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Leon Van Speybroeck of the Harvard-Smithsonian Center for Astrophysics in Cambridge Massachusetts was awarded the 2002 Bruno Rossi Prize of the High-Energy Astrophysics Division of the American Astronomy Society. The Rossi Prize is an arnual recognition of significant contributions in high-energy astrophysics in honor of the Massachusetts Institute of Technology's late Professor Bruno Rossi, an authority on cosmic ray physics and a pioneer in the field of x-ray astronomy. Van Speybroeck, who led the effort to design and make the x-ray mirrors for NASA's premier Chandra X-Ray Observatory, was recognized for a career of stellar achievements in designing precision x-ray optics. As Telescope Scientist for Chandra, he has worked for more than 20 years with a team that includes scientists and engineers from the Harvard-Smithsonian, NASA's Marshall Space Flight Center, TRW, Inc., Huhes-Danbury (now B.F. Goodrich Aerospace), Optical Coating Laboratories, Inc., and Eastman-Kodak on all aspects of the x-ray mirror assembly that is the heart of the observatory.

  15. [Opinions of the participants of 'Quit and Win' competition concerning prizes motivating to refrain from smoking].

    PubMed

    Kowalska, Alina; Stelmach, Włodzimierz; Rzeźnicki, Adam

    2009-01-01

    Big antinicotine campaigns both in Poland and worldwide, are finished with a competition with prizes of different value. Psychologists say that a prize significantly motivates a person to certain kinds of behaviour. During educational activities carried out in the time of campaign, it is recommended to use techniques of psychological interaction that would release motives most beneficial to health. The aim of the work was to recognize frequency of being influenced mostly by the possibility of winning a prize before making a decision about quitting smoking and joining the competition, and learning the opinions of prize laureates concerning efficiency of 'Quit and Win' competitions. Empirical material comes from two sources. The first one is the selected fragments of a survey study carried out at Social and Preventive Medicine Department among 1700 participants of 'Quit and Win' competition that finished the 2nd International Antinicotine Campaign in Poland. The correctly filled survey was sent by 1285 people, that is 75.6%. The second source is a fragment of a survey study carried out in 2003 among 54 laureates of 'Quit and Win' competition in Poland. The completed survey was sent by majority of the laureates, that is 34 people (f = 0.63). Possibility of winning a prize as the most important reason for taking up the attempt to stop smoking and joining the competition was pointed to by 56 respondents (4.4%), whereas the remaining people chose other reasons as the most important ones. In the group of 34 respondents who were the laureates of competitions, majority, that is 22 people (f = 0.65) claimed the competition with prizes as a very effective method of reducing smoking. Half of the surveyed (17 people) claimed the possibility of winning a few prizes of high value would be more motivating than winning one of many prizes of smaller value. As the least attractive, prize gifts were pointed to. A prize in the form of a trip or holiday was considered very popular, as

  16. Propagation of solitary waves in relativistic electron-positron-ion plasmas with kappa distributed electrons and positrons

    SciTech Connect

    Shah, Asif; Mahmood, S.; Haque, Q.

    2011-11-15

    Electrostatic ion acoustic solitary waves are studied in a plasma system comprising of relativistic ions, kappa distributed electrons, and positrons. The increase in the relativistic streaming factor and positron and electron kappa parameters cause the soliton amplitude to thrive. However, the soliton amplitude diminishes as the positron concentration is increased in the system. Our results are general and may be helpful, in understanding nonlinear phenomena in the presence of kappa distibuted electrons, positrons, and relativistically streaming ions.

  17. Positron elastic scattering from alkaline earth targets

    NASA Astrophysics Data System (ADS)

    Poveda, Luis A.; Assafrão, Denise; Mohallem, José R.

    2016-07-01

    A previously reported model potential approach [Poveda et al., Phys. Rev. A 87, 052702 (2013)] was extended to study low energy positron elastic scattering from beryllium and magnesium. The cross sections were computed for energies ranging from 10-5 eV up to well above the positronium formation threshold. The present results are in good agreement with previous reports, including the prediction of a p-wave resonance in the cross section for magnesium. The emergence of this shape resonance is connected to a trend observed in the evolution of the partial wave cross section in going from Be to Mg target. This trend lead us to speculate that a sharp d-wave resonance should be observed in positron elastic scattering from calcium. The positron-target binding energies are investigated in detail, both using the scattering information and by direct computation of the bound state energies using the model potentials. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-70120-y

  18. Resonances in Positron-molecule Interactions

    NASA Astrophysics Data System (ADS)

    Surko, C. M.

    2006-05-01

    The development of cold, trap-based beams has enabled high-resolution, energy-resolved studies of positron scattering and annihilation processes [1]. This talk focuses on three topics in this area. For hydrocarbon molecules such as alkanes (CnH2n+2), giant enhancements in annihilation rates are observed due to vibrational Feshbach resonances. The dependence of the rates on positron energy provides evidence that positrons bind to these molecules and a measure of the binding energies [1]. Recent results include evidence for a second, ``positronically excited'' bound state and new data for the methane series, CH3X, where X is a halogen. Other ``resonance-like features'' are sharp increases in the near-threshold electronic excitation cross sections for CO and N2 [2], and in the vibrational excitation cross sections for CO, CO2 and CH4 [3, 4]. Outstanding questions and the relationship of these observations to available theoretical predictions will be discussed.1. C. M. Surko, G. F. Gribakin, and S. J. Buckman, J. Phys. B 38, R57 (2005).2. J. P. Marler and C. M. Surko, Phys. Rev. A 72, 062713 (2005).3. J. P. Marler and C. M. Surko, Phys. Rev. A 72, 062702 (2005).4. J. P. Marler, G. F. Gribakin and C. M. Surko, Nuclear Instrum. and Meth. B, in press (2006).

  19. Positrons observed to originate from thunderstorms

    NASA Astrophysics Data System (ADS)

    Fishman, Gerald J.

    2011-05-01

    Thunderstorms are the result of warm, moist air moving rapidly upward, then cooling and condensing. Electrification occurs within thunderstorms (as noted by Benjamin Franklin), produced primarily by frictional processes among ice particles. This leads to lightning discharges; the types, intensities, and rates of these discharges vary greatly among thunderstorms. Even though scientists have been studying lightning since Franklin's time, new phenomena associated with thunderstorms are still being discovered. In particular, a recent finding by Briggs et al. [2011], based on observations by the Gamma-Ray Burst Monitor (GBM) instrument on NASA's satellite-based Fermi Gamma-ray Space Telescope (Fermi), shows that positrons are also generated by thunderstorms. Positrons are the antimatter form of electrons—they have the same mass and charge as an electron but are of positive rather than negative charge; hence the name positron. Observations of positrons from thunderstorms may lead to a new tool for understanding the electrification and high-energy processes occurring within thunderstorms. New theories, along with new observational techniques, are rapidly evolving in this field.

  20. Positron Annihilation in the Bipositronium Ps2

    SciTech Connect

    Bailey, David H.; Frolov, Alexei M.

    2005-07-01

    The electron-positron-pair annihilation in the bipositronium PS2 is considered. In particular, the two-, three-, one- and zero-photon annihilation rates are determined to high accuracy. The corresponding analytical expressions are also presented. Also, a large number of bound state properties have been determined for this system.

  1. Excitation of helium ion by positron impact

    SciTech Connect

    Khan, P.; Ghosh, A.S.

    1986-01-01

    Three (1s,2s,2p) and five (1s,2s,2p,3s-bar,3p-bar) -state close-coupling methods have been employed to calculate the n = 2 excitation cross sections of helium ion by positron impact. The effect of pseudostate is found to be very pronounced in the case of 1s-2s excitation.

  2. Progress Towards a Practical Multicell Positron Trap

    NASA Astrophysics Data System (ADS)

    Danielson, J. R.

    2013-10-01

    The physics and technology of positron confinement is central to a range of applications at the forefront of antimatter science. Progress in this area has been driven by the development of a suite of novel non-neutral plasma techniques whereby up to 4 ×109 positrons have now been trapped and stored. However the next generation of experiments will require orders of magnitude more positrons. This talk describes techniques to increase storage capacity to >=1012 using a novel multi-cell trap architecture. Plasmas will be stored in separate Penning-Malmberg traps (``cells'') arranged in parallel off the magnetic axis to maximize use of the magnetic field volume while minimizing the required confinement voltages. Experiments with electrons in a test structure will be described to explore the basic physics and technology of the multicell concept and to set the design of a 21-cell trap for 1012 positrons. Over 50% of a trapped plasma has been injected into an off-axis cell, and hour-long confinement of 2 ×108 particles has been achieved using rotating electric fields. Experiments are under way to identify the limits of the injection process and demonstrate confinement >1010 particles in a single off-axis cell using kilovolt confinement potentials. In collaboration with N. C. Hurst, C. J. Baker, and C. M. Surko. This work is supported by U.S. DTRA and the U.S. DOE/NSF plasma partnership.

  3. Positron Spectroscopy of Hydrothermally Grown Actinide Oxides

    DTIC Science & Technology

    2014-03-27

    In this method, the powdered material is placed in a solution which contains extremely powerful mineralizers, such as cesium fluoride for actinide...the isotope that acts as a positron source is sodium -22, which has a relatively short half-life (2.6 y) and emits a characteristic gamma photon (at

  4. Positron source position sensing detector and electronics

    DOEpatents

    Burnham, Charles A.; Bradshaw, Jr., John F.; Kaufman, David E.; Chesler, David A.; Brownell, Gordon L.

    1985-01-01

    A positron source, position sensing device, particularly with medical applications, in which positron induced gamma radiation is detected using a ring of stacked, individual scintillation crystals, a plurality of photodetectors, separated from the scintillation crystals by a light guide, and high resolution position interpolation electronics. Preferably the scintillation crystals are several times more numerous than the photodetectors with each crystal being responsible for a single scintillation event from a received gamma ray. The light guide will disperse the light emitted from gamma ray absorption over several photodetectors. Processing electronics for the output of the photodetectors resolves the location of the scintillation event to a fraction of the dimension of each photodetector. Because each positron absorption results in two 180.degree. oppositely traveling gamma rays, the detection of scintillation in pairs permits location of the positron source in a manner useful for diagnostic purposes. The processing electronics simultaneously responds to the outputs of the photodetectors to locate the scintillations to the source crystal. While it is preferable that the scintillation crystal include a plurality of stacked crystal elements, the resolving power of the processing electronics is also applicable to continuous crystal scintillators.

  5. Advanced Instrumentation for Positron Emission Tomography [PET

    DOE R&D Accomplishments Database

    Derenzo, S. E.; Budinger, T. F.

    1985-04-01

    This paper summarizes the physical processes and medical science goals that underlay modern instrumentation design for Positron Emission Tomography. The paper discusses design factors such as detector material, crystalphototube coupling, shielding geometry, sampling motion, electronics design, time-of-flight, and the interrelationships with quantitative accuracy, spatial resolution, temporal resolution, maximum data rates, and cost.

  6. Advanced instrumentation for Positron Emission Tomography

    SciTech Connect

    Derenzo, S.E.; Budinger, T.F.

    1985-04-01

    This paper summarizes the physical processes and medical science goals that underly modern instrumentation design for Positron Emission Tomography. The paper discusses design factors such as detector material, crystalphototube coupling, shielding geometry, sampling motion, electronics design, time-of-flight, and the interrelationships with quantitative accuracy, spatial resolution, temporal resolution, maximum data rates, and cost. 71 refs., 3 figs., 3 tabs.

  7. Positron and positronium interactions with Cu

    SciTech Connect

    Bromley, M.W.J.; Mitroy, J.

    2002-12-01

    The configuration-interaction (CI) method is used to investigate the interactions of positrons and positronium with copper at low energies. The calculations were performed within the framework of the fixed-core approximation with semiempirical polarization potentials used to model dynamical interactions between the active particles and the (1s-3d) core. Initially, calculations upon the e{sup +}Li system were used to refine the numerical procedures and highlighted the extreme difficulties of using an orthodox CI calculation to describe the e{sup +} Li system. The positron binding energy of e{sup +}Cu derived from a CI calculation which included electron and positron orbitals with l{<=}18 was 0.005 12 hartree while the spin-averaged annihilation rate was 0.507x10{sup 9} s{sup -1}. The configuration basis used for the bound-state calculation was also used as a part of the trial wave function for a Kohn variational calculation of positron-copper scattering. The positron-copper system has a scattering length of about 13.1a{sub 0} and the annihilation parameter Z{sub eff} at threshold was 72.9. The dipole polarizability of the neutral copper ground state was computed and found to be 41.6a{sub 0}{sup 3}. The structure of CuPs was also studied with the CI method and it was found to have a binding energy of 0.0143 hartree and an annihilation rate of {approx}2x10{sup 9} s{sup -1}.

  8. A reversal of fortunes: climate change 'winners' and 'losers' in Antarctic Peninsula penguins.

    PubMed

    Clucas, Gemma V; Dunn, Michael J; Dyke, Gareth; Emslie, Steven D; Naveen, Ron; Polito, Michael J; Pybus, Oliver G; Rogers, Alex D; Hart, Tom

    2014-06-12

    Climate change is a major threat to global biodiversity. Antarctic ecosystems are no exception. Investigating past species responses to climatic events can distinguish natural from anthropogenic impacts. Climate change produces 'winners', species that benefit from these events and 'losers', species that decline or become extinct. Using molecular techniques, we assess the demographic history and population structure of Pygoscelis penguins in the Scotia Arc related to climate warming after the Last Glacial Maximum (LGM). All three pygoscelid penguins responded positively to post-LGM warming by expanding from glacial refugia, with those breeding at higher latitudes expanding most. Northern (Pygoscelis papua papua) and Southern (Pygoscelis papua ellsworthii) gentoo sub-species likely diverged during the LGM. Comparing historical responses with the literature on current trends, we see Southern gentoo penguins are responding to current warming as they did during post-LGM warming, expanding their range southwards. Conversely, Adélie and chinstrap penguins are experiencing a 'reversal of fortunes' as they are now declining in the Antarctic Peninsula, the opposite of their response to post-LGM warming. This suggests current climate warming has decoupled historic population responses in the Antarctic Peninsula, favoring generalist gentoo penguins as climate change 'winners', while Adélie and chinstrap penguins have become climate change 'losers'.

  9. Oscillatory Behavior of Neutrophils under Opposing Chemoattractant Gradients Supports a Winner-Take-All Mechanism

    PubMed Central

    Kapoor, Ashish; He, Yuan; Mattam, Kewin S.; Hasan, Katherine M.; Olson, Luke N.; Wang, Fei; Kenis, Paul J. A.; Rao, Christopher V.

    2014-01-01

    Neutrophils constitute the largest class of white blood cells and are the first responders in the innate immune response. They are able to sense and migrate up concentration gradients of chemoattractants in search of primary sites of infection and inflammation through a process known as chemotaxis. These chemoattractants include formylated peptides and various chemokines. While much is known about chemotaxis to individual chemoattractants, far less is known about chemotaxis towards many. Previous studies have shown that in opposing gradients of intermediate chemoattractants (interleukin-8 and leukotriene B4), neutrophils preferentially migrate toward the more distant source. In this work, we investigated neutrophil chemotaxis in opposing gradients of chemoattractants using a microfluidic platform. We found that primary neutrophils exhibit oscillatory motion in opposing gradients of intermediate chemoattractants. To understand this behavior, we constructed a mathematical model of neutrophil chemotaxis. Our results suggest that sensory adaptation alone cannot explain the observed oscillatory motion. Rather, our model suggests that neutrophils employ a winner-take-all mechanism that enables them to transiently lock onto sensed targets and continuously switch between the intermediate attractant sources as they are encountered. These findings uncover a previously unseen behavior of neutrophils in opposing gradients of chemoattractants that will further aid in our understanding of neutrophil chemotaxis and the innate immune response. In addition, we propose a winner-take-all mechanism allows the cells to avoid stagnation near local chemical maxima when migrating through a network of chemoattractant sources. PMID:24465668

  10. Dynamic analysis of a general class of winner-take-all competitive neural networks.

    PubMed

    Fang, Yuguang; Cohen, Michael A; Kincaid, Thomas G

    2010-05-01

    This paper studies a general class of dynamical neural networks with lateral inhibition, exhibiting winner-take-all (WTA) behavior. These networks are motivated by a metal-oxide-semiconductor field effect transistor (MOSFET) implementation of neural networks, in which mutual competition plays a very important role. We show that for a fairly general class of competitive neural networks, WTA behavior exists. Sufficient conditions for the network to have a WTA equilibrium are obtained, and rigorous convergence analysis is carried out. The conditions for the network to have the WTA behavior obtained in this paper provide design guidelines for the network implementation and fabrication. We also demonstrate that whenever the network gets into the WTA region, it will stay in that region and settle down exponentially fast to the WTA point. This provides a speeding procedure for the decision making: as soon as it gets into the region, the winner can be declared. Finally, we show that this WTA neural network has a self-resetting property, and a resetting principle is proposed.

  11. Hebbian based learning with winner-take-all for spiking neural networks

    NASA Astrophysics Data System (ADS)

    Gupta, Ankur; Long, Lyle

    2009-03-01

    Learning methods for spiking neural networks are not as well developed as the traditional neural networks that widely use back-propagation training. We propose and implement a Hebbian based learning method with winner-take-all competition for spiking neural networks. This approach is spike time dependent which makes it naturally well suited for a network of spiking neurons. Homeostasis with Hebbian learning is implemented which ensures stability and quicker learning. Homeostasis implies that the net sum of incoming weights associated with a neuron remains the same. Winner-take-all is also implemented for competitive learning between output neurons. We implemented this learning rule on a biologically based vision processing system that we are developing, and use layers of leaky integrate and fire neurons. The network when presented with 4 bars (or Gabor filters) of different orientation learns to recognize the bar orientations (or Gabor filters). After training, each output neuron learns to recognize a bar at specific orientation and responds by firing more vigorously to that bar and less vigorously to others. These neurons are found to have bell shaped tuning curves and are similar to the simple cells experimentally observed by Hubel and Wiesel in the striate cortex of cat and monkey.

  12. Positron annihilation studies of moisture in graphite-reinforced composites

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Holt, W. H.; Mock, W., Jr.; Buckingham, R. D.

    1980-01-01

    The positron lifetime technique of monitoring absorbed moisture is applied to several composites, including graphite/polymides which are candidates for high-temperature (over 260 C) applications. The experimental setup is a conventional fast-slow coincidence system wherein the positron lifetime is measured with respect to a reference time determined by the detection of a nuclear gamma ray emitted simultaneously with the positron. From the experiments, a rate of change of positron mean lifetime per unit mass of water can be determined for each type of specimen. Positron lifetime spectra are presented for a graphite/polyimide composite and for a pure polyimide.

  13. Relativistic Positron Creation Using Ultra-Intense Short Pulse Lasers

    SciTech Connect

    Chen, H; Wilks, S; Bonlie, J; Liang, E; Myatt, J; Price, D; Meyerhofer, D; Beiersdorfer, P

    2008-08-25

    We measure up to 2 x 10{sup 10} positrons per steradian ejected out the back of {approx}mm thick gold targets when illuminated with short ({approx} 1 ps) ultra-intense ({approx} 1 x 10{sup 20} W/cm{sup 2}) laser pulses. Positrons produced predominately by the Bethe-Heitler process and have an effective temperature of 2-4 MeV, with the distribution peaking at 4-7 MeV. The angular distribution of the positrons is anisotropic. The measurements indicate the laser produced, relativistic positron densities ({approx} 10{sup 16} positrons/cm{sup 3}) are the highest ever created in the laboratory.

  14. Relativistic Positron Creation Using Ultraintense Short Pulse Lasers

    SciTech Connect

    Chen Hui; Wilks, Scott C.; Bonlie, James D.; Price, Dwight F.; Beiersdorfer, Peter; Liang, Edison P.; Myatt, Jason; Meyerhofer, David D.

    2009-03-13

    We measure up to 2x10{sup 10} positrons per steradian ejected out the back of {approx}mm thick gold targets when illuminated with short ({approx}1 ps) ultraintense ({approx}1x10{sup 20} W/cm{sup 2}) laser pulses. Positrons are produced predominately by the Bethe-Heitler process and have an effective temperature of 2-4 MeV, with the distribution peaking at 4-7 MeV. The angular distribution of the positrons is anisotropic. Modeling based on the measurements indicate the positron density to be {approx}10{sup 16} positrons/cm{sup 3}, the highest ever created in the laboratory.

  15. First platinum moderated positron beam based on neutron capture

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, C.; Kögel, G.; Repper, R.; Schreckenbach, K.; Sperr, P.; Triftshäuser, W.

    2002-12-01

    A positron beam based on absorption of high energy prompt γ-rays from thermal neutron capture in 113Cd was installed at a neutron guide of the high flux reactor at the ILL in Grenoble. Measurements were performed for various source geometries, dependent on converter mass, moderator surface and extraction voltages. The results lead to an optimised design of the in-pile positron source which will be implemented at the Munich research reactor FRM-II. The positron source consists of platinum foils acting as γ-e +e --converter and positron moderator. Due to the negative positron work function moderation in heated platinum leads to emission of monoenergetic positrons. The positron work function of polycrystalline platinum was determined to 1.95(5) eV. After acceleration to several keV by four electrical lenses the beam was magnetically guided in a solenoid field of 7.5 mT leading to a NaI-detector in order to detect the 511 keV γ-radiation of the annihilating positrons. The positron beam with a diameter of less than 20 mm yielded an intensity of 3.1×10 4 moderated positrons per second. The total moderation efficiency of the positron source was about ɛ=1.06(16)×10 -4. Within the first 20 h of operation a degradation of the moderation efficiency of 30% was observed. An annealing procedure at 873 K in air recovers the platinum moderator.

  16. Methods and apparatus for producing and storing positrons and protons

    DOEpatents

    Akers, Douglas W.

    2010-07-06

    Apparatus for producing and storing positrons may include a trap that defines an interior chamber therein and that contains an electric field and a magnetic field. The trap may further include a source material that includes atoms that, when activated by photon bombardment, become positron emitters to produce positrons. The trap may also include a moderator positioned adjacent the source material. A photon source is positioned adjacent the trap so that photons produced by the photon source bombard the source material to produce the positron emitters. Positrons from the positron emitters and moderated positrons from the moderator are confined within the interior chamber of the trap by the electric and magnetic fields. Apparatus for producing and storing protons are also disclosed.

  17. Optimization of positrons generation based on laser wakefield electron acceleration

    NASA Astrophysics Data System (ADS)

    Wu, Yuchi; Han, Dan; Zhang, Tiankui; Dong, Kegong; Zhu, Bin; Yan, Yonghong; Gu, Yuqiu

    2016-08-01

    Laser based positron represents a new particle source with short pulse duration and high charge density. Positron production based on laser wakefield electron acceleration (LWFA) has been investigated theoretically in this paper. Analytical expressions for positron spectra and yield have been obtained through a combination of LWFA and cascade shower theories. The maximum positron yield and corresponding converter thickness have been optimized as a function of driven laser power. Under the optimal condition, high energy (>100 MeV ) positron yield up to 5 ×1011 can be produced by high power femtosecond lasers at ELI-NP. The percentage of positrons shows that a quasineutral electron-positron jet can be generated by setting the converter thickness greater than 5 radiation lengths.

  18. Positron annihilation lifetime spectroscopy at a superconducting electron accelerator

    NASA Astrophysics Data System (ADS)

    Wagner, A.; Anwand, W.; Attallah, A. G.; Dornberg, G.; Elsayed, M.; Enke, D.; Hussein, A. E. M.; Krause-Rehberg, R.; Liedke, M. O.; Potzger, K.; Trinh, T. T.

    2017-01-01

    The Helmholtz-Zentrum Dresden-Rossendorf operates a superconducting linear accelerator for electrons with energies up to 35 MeV and average beam currents up to 1.6 mA. The electron beam is employed for production of several secondary beams including X-rays from bremsstrahlung production, neutrons, and positrons. The secondary positron beam after moderation feeds the Monoenergetic Positron Source (MePS) where positron annihilation lifetime (PALS) and positron annihilation Doppler-broadening experiments in materials science are performed in parallel. The adjustable repetition rate of the continuous-wave electron beams allows matching of the pulse separation to the positron lifetime in the sample under study. The energy of the positron beam can be set between 0.5 keV and 20 keV to perform depth resolved defect spectroscopy and porosity studies especially for thin films.

  19. High-yield positron systems for linear colliders

    SciTech Connect

    Clendenin, J.E.

    1989-04-01

    Linear colliders, such as the SLC, are among those accelerators for which a high-yield positron source operating at the repetition rate of the accelerator is desired. The SLC, having electron energies up to 50 GeV, presents the possibility of generating positron bunches with useful charge even exceeding that of the initial electron bunch. The exact positron yield to be obtained depends on the particular capture, transport and damping system employed. Using 31 GeV electrons impinging on a W-type converter phase-space at the target to the acceptance of the capture rf section, the SLC source is capable of producing, for every electron, up to two positrons within the acceptance of the positron damping ring. The design of this source and the performance of the positron system as built are described. Also, future prospects and limitations for high-yield positron systems are discussed. 11 refs., 5 figs., 3 tabs.

  20. Prizes to solve problems in and beyond medicine, big and small: it can work.

    PubMed

    Erren, Thomas C

    2007-01-01

    This article complements Dr. Charlton's follow-up of David Horrobin's suggestion in Nature two decades ago to offer sizeable prizes for practical approaches to either eliminate a problem in medicine or reduce the cost of its solution. Examples from the 20th and 21st centuries illustrate that prizes--small and big--have generated sustained and successful attacks on defined problems in biology, physics and, lately, mathematics. Provided that glittering prizes are offered and awarded with care, they can lead to effective problem-solving in medicine and related biomedical sciences as well.

  1. From Tomato King to World Food Prize laureate.

    PubMed

    Nelson, Philip E

    2014-01-01

    This autobiographical article describes my early years, education, and career at Purdue University. Helping form and expand the Department of Food Science at Purdue was exciting and gratifying, and working with students in the classroom and on research projects was rewarding and kept me feeling young. My research on bulk aseptic processing allowed me to help solve problems relevant to the tomato industry, but I learned later that it had much broader relevance. I certainly never expected the impact and visibility of the work to result in my being awarded the World Food Prize. Being the first food scientist to win this award has enabled me to focus increased attention on the need to reduce food losses.

  2. How Citation Boosts Promote Scientific Paradigm Shifts and Nobel Prizes

    PubMed Central

    Mazloumian, Amin; Eom, Young-Ho; Helbing, Dirk; Lozano, Sergi; Fortunato, Santo

    2011-01-01

    Nobel Prizes are commonly seen to be among the most prestigious achievements of our times. Based on mining several million citations, we quantitatively analyze the processes driving paradigm shifts in science. We find that groundbreaking discoveries of Nobel Prize Laureates and other famous scientists are not only acknowledged by many citations of their landmark papers. Surprisingly, they also boost the citation rates of their previous publications. Given that innovations must outcompete the rich-gets-richer effect for scientific citations, it turns out that they can make their way only through citation cascades. A quantitative analysis reveals how and why they happen. Science appears to behave like a self-organized critical system, in which citation cascades of all sizes occur, from continuous scientific progress all the way up to scientific revolutions, which change the way we see our world. Measuring the “boosting effect” of landmark papers, our analysis reveals how new ideas and new players can make their way and finally triumph in a world dominated by established paradigms. The underlying “boost factor” is also useful to discover scientific breakthroughs and talents much earlier than through classical citation analysis, which by now has become a widespread method to measure scientific excellence, influencing scientific careers and the distribution of research funds. Our findings reveal patterns of collective social behavior, which are also interesting from an attention economics perspective. Understanding the origin of scientific authority may therefore ultimately help to explain how social influence comes about and why the value of goods depends so strongly on the attention they attract. PMID:21573229

  3. [From apprenticeship to Nobel Prize: Henri Moissan's fabulous destiny].

    PubMed

    Lafont, O

    2008-01-01

    Born in Paris on September 28, 1852, son of an eastern railways' employee and of a dressmaker, Henri Moissan's secondary schooling in Meaux did not allow him to get access to the sesame diploma "baccalauréat" (GCE). In 1869, he did obtain a special certificate of secondary schooling so that he could become an apprentice in watch making. That could have been the end of the story, but dreadful event for France appeared to have beneficial effects for Moissan. Under the threat of the Prussian army, Moissan's family took refuge near Paris. This gave the young Henri the opportunity to register as a student for the second-class pharmacy diploma, which did not need, at the time, the GCE. Moissan became then a trainee in pharmacy in 1871. Meanwhile, he followed the special schooling of "Ecole de chimie" founded by E. Frémy, and then joined the laboratory of Dehérain at the Museum, where he worked in plant physiology. He finally obtained the famous "baccalauréat" (GCE) and could register as a student in first-class pharmacy. He became a pharmacist as well as a doctor in sciences. In 1883, Moissan was named professor at the school of pharmacy in Paris. In 1886, he isolated fluorine by electrolysis of fluorhydric acid, in the presence of potassium fluoride, at a low temperature. He then studied diamond synthesis and gave a start to high temperature chemistry, designing his famous furnace. These findings and many others allowed Moissan to rise to membership in many learned academies around the world. Crowning achievement, Moissan won the Nobel Prize in 1906. A man of culture, collector of autographs and paintings, he died in 1907. Nothing of that would have been possible if there had not been a second-class pharmacist diploma. The history of Henri Moissan is one of a rise from apprenticeship to the Nobel Prize.

  4. How citation boosts promote scientific paradigm shifts and nobel prizes.

    PubMed

    Mazloumian, Amin; Eom, Young-Ho; Helbing, Dirk; Lozano, Sergi; Fortunato, Santo

    2011-05-04

    Nobel Prizes are commonly seen to be among the most prestigious achievements of our times. Based on mining several million citations, we quantitatively analyze the processes driving paradigm shifts in science. We find that groundbreaking discoveries of Nobel Prize Laureates and other famous scientists are not only acknowledged by many citations of their landmark papers. Surprisingly, they also boost the citation rates of their previous publications. Given that innovations must outcompete the rich-gets-richer effect for scientific citations, it turns out that they can make their way only through citation cascades. A quantitative analysis reveals how and why they happen. Science appears to behave like a self-organized critical system, in which citation cascades of all sizes occur, from continuous scientific progress all the way up to scientific revolutions, which change the way we see our world. Measuring the "boosting effect" of landmark papers, our analysis reveals how new ideas and new players can make their way and finally triumph in a world dominated by established paradigms. The underlying "boost factor" is also useful to discover scientific breakthroughs and talents much earlier than through classical citation analysis, which by now has become a widespread method to measure scientific excellence, influencing scientific careers and the distribution of research funds. Our findings reveal patterns of collective social behavior, which are also interesting from an attention economics perspective. Understanding the origin of scientific authority may therefore ultimately help to explain how social influence comes about and why the value of goods depends so strongly on the attention they attract.

  5. The Newbery/Printz Companion: Booktalk and Related Materials for Award Winners and Honor Books, Third Edition

    ERIC Educational Resources Information Center

    Gillespie, John T.; Naden, Corinne J.

    2006-01-01

    This comprehensive and practical guide to the influential Newbery and Printz awards for children's and young adult literature provides information on each year's winners and honor books, as well as on the awards themselves and the librarians for whom they are named. For each award-winning book, there is a plot summary, list of characters and…

  6. An Evaluation of the Trends of Realism in Caldecott Winner and First Honor Books 1966-1986.

    ERIC Educational Resources Information Center

    Smith, John A., Jr.; Napier, Georgia

    To determine if there were any consistent tendencies toward the abstract or toward impressionism in the illustration of children's books between the years 1966 and 1986, a study examined the illustrations of Caldecott winners and Honor books. The study replicated John Stewig's study (using his evaluation instrument) of the same topic which covered…

  7. Application of positron annihilation in materials science

    SciTech Connect

    Siegel, R.W.; Fluss, M.J.; Smedskjaer, L.C.

    1984-05-01

    Owing to the ability of the positron to annihilate from a variety of defect-trapped states, positron annihilation spectroscopy (PAS) has been applied increasingly to the characterization and study of defects in materials in recent years. In metals particularly, it has been demonstrated that PAS can yield defect-specific information which, by itself or in conjunction with more traditional experimental techniques, has already made a significant impact upon the determination of atomic-defect properties and the monitoring and characterization of vacancy-like microstructure development, as occurs during post-irradiation annealing. The applications of PAS are now actively expanding to the study of more complex defect-related phenomena in irradiated or deformed metals and alloys, phase transformations and structural disorder, surfaces and near-surface defect characterization. A number of these applications in materials science are reviewed and discussed with respect to profitable future directions.

  8. Experimental study of a crystal positron source

    NASA Astrophysics Data System (ADS)

    Chehab, R.; Cizeron, R.; Sylvia, C.; Baier, V.; Beloborodov, K.; Bukin, A.; Burdin, S.; Dimova, T.; Drozdetsky, A.; Druzhinin, V.; Dubrovin, M.; Golubev, V.; Serednyakov, S.; Shary, V.; Strakhovenko, V.; Artru, X.; Chevallier, M.; Dauvergne, D.; Kirsch, R.; Lautesse, Ph.; Poizat, J.-C.; Remillieux, J.; Jejcic, A.; Keppler, P.; Major, J.; Gatignon, L.; Bochek, G.; Kulibaba, V.; Maslov, N.; Bogdanov, A.; Potylitsin, A.; Vnukov, I.

    2002-01-01

    Tungsten crystals oriented on their <111> axis, were submitted to 6 and 10 GeV electron beams on the SPS-CERN transfer lines. The crystals, 4 and 8 mm thick, used alone or associated to 4 mm thick amorphous disk, were studied as positron sources. The emerging positrons were detected by a Drift Chamber partially immersed in a magnetic field, where their trajectories were reconstructed providing the energy spectrum and the angular distribution. Significant enhancements were observed for the crystal source when compared to the amorphous one of the same thickness. The gain was larger than 3 and 2 for the 4 mm and 8 mm targets, respectively. The presented results look very promising for e+e- linear colliders.

  9. Positron Emission Tomography Imaging of Hypoxia

    PubMed Central

    Lapi, Suzanne E.; Voller, Thomas F.; Welch, Michael J.

    2009-01-01

    Synopsis Hypoxia imaging has applications in functional recovery in ischemic events such as stroke and myocardial ischemia, but especially in tumors in which hypoxia can be predictive of treatment response and overall prognosis. Recently there has been development of imaging agents utilizing positron emission tomography for non-invasive imaging of hypoxia. Many of these PET agents have come to the forefront of hypoxia imaging. Halogenated PET nitroimidazole imaging agents labeled with 18F (t1/2 = 110 m) and 124I (t1/2 = 110 m) have been under investigation for the last 25 years, with radiometal agents (64Cu-ATSM) being developed more recently. This review focuses on these positron emission tomography imaging agents for hypoxia. PMID:20046923

  10. Positron scattering and annihilation from hydrogenlike ions

    SciTech Connect

    Novikov, S.A.; Bromley, M.W.J.; Mitroy, J.

    2004-05-01

    The Kohn variational method is used with a configuration-interaction-type wave function to determine the J=0 and J=1 phase shifts and annihilation parameter Z{sub eff} for positron-hydrogenic ion scattering. The phase shifts are within 1-2% of the best previous calculations. The values of Z{sub eff} are small and do not exceed unity for any of the momenta considered. At thermal energies Z{sub eff} is minute with a value of order 10{sup -50} occurring for He{sup +} at k=0.05a{sub 0}{sup -1}. In addition to the variational calculations, analytic expressions for the phase shift and annihilation parameters within the Coulomb wave Born approximation are derived and used to help elucidate the dynamics of positron collisions with positive ions.

  11. Cold Positrons from Decaying Dark Matter

    SciTech Connect

    Boubekeur, Lotfi; Dodelson, Scott; Vives, Oscar

    2012-11-01

    Many models of dark matter contain more than one new particle beyond those in the Standard Model. Often heavier particles decay into the lightest dark matter particle as the Universe evolves. Here we explore the possibilities that arise if one of the products in a (Heavy Particle) $\\rightarrow$ (Dark Matter) decay is a positron, and the lifetime is shorter than the age of the Universe. The positrons cool down by scattering off the cosmic microwave background and eventually annihilate when they fall into Galactic potential wells. The resulting 511 keV flux not only places constraints on this class of models but might even be consistent with that observed by the INTEGRAL satellite.

  12. "Often a Bridesmaid, Never a Bride": Frank Grimes and the Pulitzer Prize for Editorial Writing.

    ERIC Educational Resources Information Center

    Marler, Charles H.

    1985-01-01

    Argues that Grimes, editor of the "Abilene Reporter-News" for more than 40 years, was denied the Pulitzer because of the manuevering of Arthur Krock, a powerful figure on the Pulitzer Prize Advisory Board. (FL)

  13. [On the Awarding of the First Nobel Prize for Physiology or Medicine to Emil von Behring].

    PubMed

    Hansson, Nils; Enke, Ulrike

    2015-12-01

    In his will of 1895, the Swedish inventor Alfred Nobel laid the foundation for prizes in physics, chemistry, physiology or medicine, literature, and peace to those who had "conferred the greatest benefit on mankind" during the last year. The Nobel Prize is today widely considered as the most prestigious international symbol of scientific excellence, but it still is an exciting research question how it gained such prestige. Drawing on files from the Emil von Behring Archive in Marburg, Germany, and the Archive of the Nobel Assembly for Physiology or Medicine in Stockholm this essay aims at shedding light on why the first Nobel Prize for Physiology or Medicine in 1901 was awarded the German immunologist Emil von Behring, and how this decision was viewed at that time. This study is part of a research project that explores mechanisms leading to scientific recognition by using the example of the Nobel Prize for Physiology or Medicine.

  14. Nobel Prize for Physical Therapy? Rise, Fall, and Revival of Medico-Mechanical Institutes.

    PubMed

    Hansson, Nils; Ottosson, Anders

    2015-08-01

    This historical vignette explores the considerations of the Nobel Prize Committee for Physiology or Medicine by vetting the Nobel Prize chances of Dr Gustaf Zander (1835-1920). His way to stardom started 150 years ago when he began mechanizing the passive and active movements that physical therapists manually used to treat diseases. A glance at his machines shows that they parallel surprisingly well what can be found in modern fitness studios. By combining files from the Nobel Prize Archive and sources from the first physical therapists, this vignette pieces together why Zander was considered one of the best candidates for the Nobel Prize in 1916. By providing this glimpse of history, questions about the origin of physical therapy concepts and the profession of the physical therapist are raised.

  15. The Nobel Prize in the Physics Class: Science, History, and Glamour

    NASA Astrophysics Data System (ADS)

    Eshach, Haim

    2009-10-01

    This paper introduces a novel strategy for teaching physics: using the Nobel Physics Prize as an organizational theme for high school or even first year university physics, bringing together history, social contexts of science, and central themes in modern physics. The idea underlying the strategy is that the glamour and glitter of the Nobel Prize story may attract and motivate high school students to open-up to scientific topics and thus be spurred to pursue science. The two major arguments for the method are that if presented in story form Nobel Prizes naturally incorporate the philosophical and historical aspects of science and therefore enable teaching about science as well as teaching science itself; and that such instruction implements case-based teaching principles, which is how humans naturally think, learn, and remember. Finally, the paper presents the storycase of the Nobel Prize Einstein received for his discovery of the law of the photoelectric effect as a concrete illustration of classroom implementation.

  16. Positron spectroscopy of 2D materials using an advanced high intensity positron beam

    NASA Astrophysics Data System (ADS)

    McDonald, A.; Chirayath, V.; Lim, Z.; Gladen, R.; Chrysler, M.; Fairchild, A.; Koymen, A.; Weiss, A.

    An advanced high intensity variable energy positron beam(~1eV to 20keV) has been designed, tested and utilized for the first coincidence Doppler broadening (CDB) measurements on 6-8 layers graphene on polycrystalline Cu sample. The system is capable of simultaneous Positron annihilation induced Auger electron Spectroscopy (PAES) and CDB measurements giving it unparalleled sensitivity to chemical structure at external surfaces, interfaces and internal pore surfaces. The system has a 3m flight path up to a micro channel plate (MCP) for the Auger electrons emitted from the sample. This gives a superior energy resolution for PAES. A solid rare gas(Neon) moderator was used for the generation of the monoenergetic positron beam. The positrons were successfully transported to the sample chamber using axial magnetic field generated with a series of Helmholtz coils. We will discuss the PAES and coincidence Doppler broadening measurements on graphene -Cu sample and present an analysis of the gamma spectra which indicates that a fraction of the positrons implanted at energies 7-60eV can become trapped at the graphene/metal interface. This work was supported by NSF Grant No. DMR 1508719 and DMR 1338130.

  17. Dipole configuration for confinement of positrons and electron-positron plasma

    NASA Astrophysics Data System (ADS)

    Stenson, E. V.; Saitoh, H.; Horn-Stanja, J.; Hergenhahn, U.; Paschkowski, N.; Sunn Pedersen, T.; Stoneking, M. R.; Dickmann, M.; Singer, M.; Vohburger, S.; Hugenschmidt, C.; Schweikhard, L.; Danielson, J. R.; Surko, C. M.

    2016-10-01

    Laboratory creation and confinement of electron-positron plasmas, which are expected to exhibit atypical plasma physics characteristics, would enable tests of many theory and simulation predictions (e.g., the stabilization of anomalous transport mechanisms). This is the goal of APEX/PAX (A Positron-Electron eXperiment/Positron Accumulation eXperiment). Following demonstration of efficient (38%) E ×B injection and subsequent confinement (τ = 3-5 ms) of cold positrons in a dipole magnetic field, the system is undergoing upgrades from a supported permanent magnet to a supported HTSC (high-temperature superconductor) coil, then to a levitated HTSC coil suitable for the simultaneous confinement of electrons and positrons. This contribution will report on the design and testing of the new systems and subsystems (e.g., for cooling, excitation, and levitation) and, if available, on results of upcoming experiments using a ``rotating wall'' to generate inward particle flux deeper into the confinement region. on behalf of the APEX/PAX team and collaborators.

  18. Positrons for Antihydrogen with ATRAP: efficient transfer of large positron numbers

    NASA Astrophysics Data System (ADS)

    Storry, Cody; Comeau, Daniel; Dror, Asaf; Fitzakerley, Daniel; George, Matthew; Hessels, Eric; Weel, Matthew

    2012-06-01

    Positrons accumulated in a room-temperature buffer-gas-cooled positron accumulator are efficiently transferred into a superconducting solenoid which houses the ATRAP cryogenic Penning trap for antihydrogen research. The positrons are guided along a 9-meter-long magnetic guide which connects the central field lines of the 0.15-tesla field in the positron accumulator to central magnetic field lines of the superconducting solenoid. Seventy independently-controllable electromagnets are required to overcome the fringing field of the large-bore superconducting solenoid. The guide includes both a 15 degree upward bend and a 105 degree downward bend to account for the orthogonal orientation of the accumulator with respect to the cryogenic Penning trap. Low-energy positrons ejected from the accumulator follow the magnetic field lines within the guide and are transferred into the superconducting solenoid with nearly 100% efficiency. 7 meters of 5-cm-diameter stainless-steel tube, and a 20-mm-long, 1.5-mm-diameter cryogenic pumping restriction ensure that the 10-2 mbar pressure in the accumulator is well isolated from the extreme vacuum required in the Penning trap to allow long antimatter storage times.

  19. Positron-inert gas differential elastic scattering

    NASA Technical Reports Server (NTRS)

    Kauppila, W. E.; Smith, Steven J.; Kwan, C. K.; Stein, T. S.

    1990-01-01

    Measurements are being made in a crossed beam experiment of the relative elastic differential cross section (DCS) for 5 to 300 eV positrons scattering from inert gas atoms (He, Ne, Ar, Kr, and Xe) in the angular range from 30 to 134 deg. Results obtained at energies around the positronium (Ps) formation threshold provide evidence that Ps formation and possibly other inelastic channels have an effect on the elastic scattering channel.

  20. Imaging Prostate Cancer with Positron Emission Tomography

    DTIC Science & Technology

    2014-07-01

    AD_________________ Award Number: W81XWH-13-1-0125 TITLE: Imaging Prostate Cancer with Positron Emission Tomography...ABOVE ADDRESS. 1. REPORT DATE 2014 2. REPORT TYPE Annual 3. DATES COVERED 01 Sept 2013-31 Aug 2014 4. TITLE AND SUBTITLE Imaging Prostate Cancer ...proposal is to develop peptide based radiopharmaceuticals and evaluate them as PET imaging agents in preclinical animal models of prostate cancer

  1. Positron studies of defected metals, metallic surfaces

    SciTech Connect

    Bansil, A.

    1991-01-01

    Specific problems proposed under this project included the treatment of electronic structure and momentum density in various disordered and defected systems. Since 1987, when the new high-temperature superconductors were discovered, the project focused extensively on questions concerning the electronic structure and Fermiology of high-[Tc] superconductors, in particular, (i) momentum density and positron experiments, (ii) angle-resolved photoemission intensities, (iii) effects of disorder and substitutions in the high-[Tc]'s.

  2. Cosmic-ray Positrons from Millisecond Pulsars

    NASA Astrophysics Data System (ADS)

    Venter, C.; Kopp, A.; Harding, A. K.; Gonthier, P. L.; Büsching, I.

    2015-07-01

    Observations by the Fermi Large Area Telescope of γ-ray millisecond pulsar (MSP) light curves imply copious pair production in their magnetospheres, and not exclusively in those of younger pulsars. Such pair cascades may be a primary source of Galactic electrons and positrons, contributing to the observed enhancement in positron flux above ∼10 GeV. Fermi has also uncovered many new MSPs, impacting Galactic stellar population models. We investigate the contribution of Galactic MSPs to the flux of terrestrial cosmic-ray electrons and positrons. Our population synthesis code predicts the source properties of present-day MSPs. We simulate their pair spectra invoking an offset-dipole magnetic field. We also consider positrons and electrons that have been further accelerated to energies of several TeV by strong intrabinary shocks in black widow (BW) and redback (RB) systems. Since MSPs are not surrounded by pulsar wind nebulae or supernova shells, we assume that the pairs freely escape and undergo losses only in the intergalactic medium. We compute the transported pair spectra at Earth, following their diffusion and energy loss through the Galaxy. The predicted particle flux increases for non-zero offsets of the magnetic polar caps. Pair cascades from the magnetospheres of MSPs are only modest contributors around a few tens of GeV to the lepton fluxes measured by the Alpha Magnetic Spectrometer, PAMELA, and Fermi, after which this component cuts off. The contribution by BWs and RBs may, however, reach levels of a few tens of percent at tens of TeV, depending on model parameters.

  3. COSMIC-RAY POSITRONS FROM MILLISECOND PULSARS

    SciTech Connect

    Venter, C.; Kopp, A.; Büsching, I.; Harding, A. K.; Gonthier, P. L.

    2015-07-10

    Observations by the Fermi Large Area Telescope of γ-ray millisecond pulsar (MSP) light curves imply copious pair production in their magnetospheres, and not exclusively in those of younger pulsars. Such pair cascades may be a primary source of Galactic electrons and positrons, contributing to the observed enhancement in positron flux above ∼10 GeV. Fermi has also uncovered many new MSPs, impacting Galactic stellar population models. We investigate the contribution of Galactic MSPs to the flux of terrestrial cosmic-ray electrons and positrons. Our population synthesis code predicts the source properties of present-day MSPs. We simulate their pair spectra invoking an offset-dipole magnetic field. We also consider positrons and electrons that have been further accelerated to energies of several TeV by strong intrabinary shocks in black widow (BW) and redback (RB) systems. Since MSPs are not surrounded by pulsar wind nebulae or supernova shells, we assume that the pairs freely escape and undergo losses only in the intergalactic medium. We compute the transported pair spectra at Earth, following their diffusion and energy loss through the Galaxy. The predicted particle flux increases for non-zero offsets of the magnetic polar caps. Pair cascades from the magnetospheres of MSPs are only modest contributors around a few tens of GeV to the lepton fluxes measured by the Alpha Magnetic Spectrometer, PAMELA, and Fermi, after which this component cuts off. The contribution by BWs and RBs may, however, reach levels of a few tens of percent at tens of TeV, depending on model parameters.

  4. Positron annihilation study of P implanted Si

    SciTech Connect

    Asoka-Kumar, P.; Au, H.L.; Lynn, K.G. ); Sferlazzo, P. . SED Division)

    1992-01-01

    High-energy ion implantation (above 200 keV) is now commonly used in a variety of VLSI processes. The high energy required for these implants is often achieved by implanting multiply charged ions, which inevitably brings in the problem of low-energy ion contamination. The low-energy contamination is difficult to diagnose and detect. Positron annihilation spectroscopy is used to examine the defect distributions in these high energy implants with varying degrees of contamination.

  5. Positron annihilation study of P implanted Si

    SciTech Connect

    Asoka-Kumar, P.; Au, H.L.; Lynn, K.G.; Sferlazzo, P.

    1992-12-01

    High-energy ion implantation (above 200 keV) is now commonly used in a variety of VLSI processes. The high energy required for these implants is often achieved by implanting multiply charged ions, which inevitably brings in the problem of low-energy ion contamination. The low-energy contamination is difficult to diagnose and detect. Positron annihilation spectroscopy is used to examine the defect distributions in these high energy implants with varying degrees of contamination.

  6. The Clic Electron and Positron Polarized Sources

    NASA Astrophysics Data System (ADS)

    Rinolfi, L.

    2011-01-01

    The CLIC polarized electron source is based on a DC gun where the photocathode is illuminated by a laser beam. Each micro-bunch has a charge of 6 × 109 e-, a width of 100 ps and a repetition rate of 2 GHz. A peak current of 10 A in the micro-bunch is a challenge for the surface charge limit of the photo-cathode. Two options are feasible to generate the 2 GHz e- bunch train: 100 ps micro-bunches can be extracted from the photo-cathode either by a 2 GHz laser system or by generating a macro-bunch using a ~200 ns laser pulse and a subsequent RF bunching system to produce the appropriate micro-bunch structure. Recent results obtained by SLAC, for the latter case, are presented. The polarized positron source is based on a positron production scheme in which polarized photons are produced by a laser Compton scattering process. The resulting circularly-polarized gamma photons are sent onto a target, producing pairs of longitudinally polarized electrons and positrons. The Compton backscattering process occurs either in a Compton ring, where a 1 GeV electron beam interacts with circularly-polarized photons in an optical resonator or in a 1.8 GeV Compton Energy Recovery Linac (ERL) or in a 6 GeV Linac with several optical cavities. The undulator scheme is also studied. The nominal CLIC e+ bunch population is 6.7 × 109 particles per bunch at 200 MeV. The tradeoff between e+ yield and level of polarization is an important topic. The overall scheme for both polarized electron and positron beams is described.

  7. Positron annihilation in superconducting 123 compounds

    SciTech Connect

    Peter, M.; Manuel, A.A.; Erb, A. . Dept. of Physics of Condensed Matter)

    1998-12-20

    After a brief review of the theory of angular correlation of positron annihilation radiation (ACAR), the authors illustrate experimental principles and give examples of successful determination of electron momentum density (EMD) and of positron lifetime in solids. The central question which the authors try to answer concerns the contribution of positron spectroscopy to the knowledge and understanding of the new high temperature superconducting oxides. They find that in these oxides also, partially filled bands exist and they can observe parts of their Fermi surface and measure lifetimes in accordance with band theoretical calculations. There are characteristic differences, however. The intensity of the anisotropy of the ACAR signal is below theoretical expectation and signals depend on sample preparation. Recent studies by the Geneva group have concerned dependence of the signals on impurities, on oxygen content and on the thermal history of preparation. Of particular interest are correlations between the variations of these signals and between the variations of structural and transport properties in these substances. Besides deliberate additions of impurities, the Geneva group also reports progress in the preparations of samples of highest purity (barium zirconate crucibles). The alloy series Pr[sub x]Y[sub 1[minus]x]Ba[sub 2]Cu[sub 3]O[sub 7[minus][delta

  8. Feasibility study for positron emission mammography.

    PubMed

    Thompson, C J; Murthy, K; Weinberg, I N; Mako, F

    1994-04-01

    A feasibility study is presented for a small, low-cost, dedicated device for positron emission mammography. Two detector arrays above and below the breast would be placed in a conventional mammography unit. These detectors are sensitive to positron annihilation radiation, and are connected to a coincidence circuit and a multiplane image memory. Images of the distribution of positron-emitting isotope are obtained in real time by incrementing the memory location at the intersection of each line of response. Monte Carlo simulations of a breast phantom are compared with actual scans of this phantom in a conventional PET scanner. The simulations and experimental data are used to predict the performance of the proposed system. Spatial resolution experiments using very narrow bismuth germanate BGO crystals suggest that spatial resolutions of about 2 mm should be possible. The efficiency of the proposed device is about ten times that of a conventional brain scanner. The scatter fraction is greater, but the scattered radiation has a very flat distribution. By designing the device to fit in an existing mammography unit, conventional mammograms can be taken after the injection of the radio-pharmaceutical allowing exact registration of the emission and conventional mammographic images.

  9. New generation electron-positron factories

    NASA Astrophysics Data System (ADS)

    Zobov, Mikhail

    2011-09-01

    In 2010 we celebrate 50 years since commissioning of the first particle storage ring ADA in Frascati (Italy) that also became the first electron-positron collider in 1964. After that date the particle colliders have increased their intensity, luminosity and energy by several orders of magnitude. Namely, because of the high stored beam currents and high rate of useful physics events (luminosity) the modern electron-positron colliders are called "factories". However, the fundamental physics has required luminosities by 1-2 orders of magnitudes higher with respect to those presently achieved. This task can be accomplished by designing a new generation of factories exploiting the potential of a new collision scheme based on the Crab Waist (CW) collision concept recently proposed and successfully tested at Frascati. In this paper we discuss the performance and limitations of the present generation electron-positron factories and give a brief overview of new ideas and collision schemes proposed for further collider luminosity increase. In more detail we describe the CW collision concept and the results of the crab waist collision tests in DAϕNE, the Italian ϕ-factory. Finally, we briefly describe most advanced projects of the next generation factories based on the CW concept: SuperB in Italy, SuperKEKB in Japan and SuperC-Tau in Russia.

  10. Advances in positron and electron scattering*

    NASA Astrophysics Data System (ADS)

    Limão-Vieira, Paulo; García, Gustavo; Krishnakumar, E.; Petrović, Zoran; Sullivan, James; Tanuma, Hajime

    2016-10-01

    The topical issue on Advances in Positron and Electron Scattering" combines contributions from POSMOL 2015 together with others devoted to celebrate the unprecedented scientific careers of our loyal colleagues and trusted friends Steve Buckman (Australian National University, Australia) and Michael Allan (University of Fribourg, Switzerland) on the occasion of their retirements. POSMOL 2015, the XVIII International Workshop on Low-Energy Positron and Positronium Physics and the XIX International Symposium on Electron-Molecule Collisions and Swarms, was held at Universidade NOVA de Lisboa, Lisboa, Portugal, from 17-20 July 2015. The international workshop and symposium allowed to achieve a very privileged forum of sharing and developing our scientific expertise on current aspects of positron, positronium and antiproton interactions with electrons, atoms, molecules and solid surfaces, and related topics, as well as electron interactions with molecules in both gaseous and condensed phases. Particular topics include studies of electron interactions with biomolecules, electron induced surface chemistry and the study of plasma processes. Recent developments in the study of swarms are also fully addressed.

  11. Multiscale modeling of nerve agent hydrolysis mechanisms: a tale of two Nobel Prizes

    NASA Astrophysics Data System (ADS)

    Field, Martin J.; Wymore, Troy W.

    2014-10-01

    The 2013 Nobel Prize in Chemistry was awarded for the development of multiscale models for complex chemical systems, whereas the 2013 Peace Prize was given to the Organisation for the Prohibition of Chemical Weapons for their efforts to eliminate chemical warfare agents. This review relates the two by introducing the field of multiscale modeling and highlighting its application to the study of the biological mechanisms by which selected chemical weapon agents exert their effects at an atomic level.

  12. From Stealing Fire to Cellular Reprogramming: A Scientific History Leading to the 2012 Nobel Prize

    PubMed Central

    Lensch, M. William; Mummery, Christine L.

    2013-01-01

    Cellular reprogramming was recently “crowned” with the award of the Nobel Prize to two of its groundbreaking researchers, Sir John Gurdon and Shinya Yamanaka. The recent link between reprogramming and stem cells makes this appear almost a new field of research, but its historical roots have actually spanned more than a century. Here, the Nobel Prize in Physiology or Medicine 2012 is placed in its historical context. PMID:24052937

  13. From stealing fire to cellular reprogramming: a scientific history leading to the 2012 Nobel Prize.

    PubMed

    Lensch, M William; Mummery, Christine L

    2013-06-04

    Cellular reprogramming was recently "crowned" with the award of the Nobel Prize to two of its groundbreaking researchers, Sir John Gurdon and Shinya Yamanaka. The recent link between reprogramming and stem cells makes this appear almost a new field of research, but its historical roots have actually spanned more than a century. Here, the Nobel Prize in Physiology or Medicine 2012 is placed in its historical context.

  14. The Stock Performance of C. Everett Koop Award Winners Compared With the Standard & Poor's 500 Index

    PubMed Central

    Goetzel, Ron Z.; Fabius, Raymond; Fabius, Dan; Roemer, Enid C.; Thornton, Nicole; Kelly, Rebecca K.; Pelletier, Kenneth R.

    2016-01-01

    Objective: To explore the link between companies investing in the health and well-being programs of their employees and stock market performance. Methods: Stock performance of C. Everett Koop National Health Award winners (n = 26) was measured over time and compared with the average performance of companies comprising the Standard and Poor's (S&P) 500 Index. Results: The Koop Award portfolio outperformed the S&P 500 Index. In the 14-year period tracked (2000–2014), Koop Award winners’ stock values appreciated by 325% compared with the market average appreciation of 105%. Conclusions: This study supports prior and ongoing research demonstrating a higher market valuation—an affirmation of business success by Wall Street investors—of socially responsible companies that invest in the health and well-being of their workers when compared with other publicly traded firms. PMID:26716843

  15. Using transactional analysis to improve clinical and educational supervision: the Drama and Winner's triangles.

    PubMed

    McKimm, Judy; Forrest, Kirsty

    2010-05-01

    The supervisor-trainee relationship is fundamental in ensuring the best continuing education for all trainees. One of the key skills of supervision is being able to communicate effectively; however, this is sometimes difficult. In this article we explore how two transactional analysis models, the Drama and Winner's triangles, can help supervisors work and communicate more effectively with trainees. All supervisors will have had a 'heartsink moment' before meeting a known trainee. The models can be used to explain these situations and what exactly is happening to the communication. The models provide methods of breaking free from these frustrating encounters and moving on with the relationship with your trainee. The models also help us understand the ways in which we can easily be pulled into games and offer insight into our own behaviours and relationships, not only with trainees, but also with patients, carers and colleagues. Real life scenarios are used throughout to explain the models.

  16. The cumulative impact of annual coral bleaching can turn some coral species winners into losers.

    PubMed

    Grottoli, Andréa G; Warner, Mark E; Levas, Stephen J; Aschaffenburg, Matthew D; Schoepf, Verena; McGinley, Michael; Baumann, Justin; Matsui, Yohei

    2014-12-01

    Mass coral bleaching events caused by elevated seawater temperatures result in extensive coral loss throughout the tropics, and are projected to increase in frequency and severity. If bleaching becomes an annual event later in this century, more than 90% of coral reefs worldwide may be at risk of long-term degradation. While corals can recover from single isolated bleaching and can acclimate to recurring bleaching events that are separated by multiple years, it is currently unknown if and how they will survive and possibly acclimatize to annual coral bleaching. Here, we demonstrate for the first time that annual coral bleaching can dramatically alter thermal tolerance in Caribbean corals. We found that high coral energy reserves and changes in the dominant algal endosymbiont type (Symbiodinium spp.) facilitated rapid acclimation in Porites divaricata, whereas low energy reserves and a lack of algal phenotypic plasticity significantly increased susceptibility in Porites astreoides to bleaching the following year. Phenotypic plasticity in the dominant endosymbiont type of Orbicella faveolata did not prevent repeat bleaching, but may have facilitated rapid recovery. Thus, coral holobiont response to an isolated single bleaching event is not an accurate predictor of its response to bleaching the following year. Rather, the cumulative impact of annual coral bleaching can turn some coral species 'winners' into 'losers', and can also facilitate acclimation and turn some coral species 'losers' into 'winners'. Overall, these findings indicate that cumulative impact of annual coral bleaching could result in some species becoming increasingly susceptible to bleaching and face a long-term decline, while phenotypically plastic coral species will acclimatize and persist. Thus, annual coral bleaching and recovery could contribute to the selective loss of coral diversity as well as the overall decline of coral reefs in the Caribbean.

  17. When a misperception favors a tragedy: Carlos Chagas and the Nobel Prize of 1921.

    PubMed

    Bestetti, Reinaldo B; Couto, Lucélio B; Cardinalli-Neto, Augusto

    2013-11-20

    Carlos Chagas, the discoverer of Chagas' disease was nominated to the Nobel Prize in 1921, but none did win the prize in that year. As a leader of a young scientist team, he discovered all aspects of the new disease from 1909 to 1920. It is still obscure why he did not win the Nobel Prize in 1921. Chagas was discarded by Gunnar Hedrèn on April 16, 1921. Hedrèn should have made a written report about the details of his evaluation to the Nobel Committee. However, such a document has not been found in the Nobel Committee Archives. No evidence of detractions made by Brazilian scientists on Chagas was found. Since Chagas nomination was consistent with the Nobel Committee requirements, as seen in the presentation letter by until now unknown Cypriano de Freitas, it become clear that Chagas did not win the Nobel Prize exclusively because the Nobel Committee did not perceive the importance of his discovery. Thus, it would be fair a posthumous Nobel Prize of 1921 to Carlos Chagas. A diploma of the Nobel Prize, as precedent with Dogmack in 1947, would recognize the merit of the scientist who made the most complete medical discovery of all times.

  18. High-field capture section for SLC positron source

    SciTech Connect

    Hoag, H.A.; Deruyter, H.; Kramer, J.; Yao, C.G.

    1986-05-01

    The positron source for SLC is being installed at the two-thirds point on the SLAC linac. Electron bunches at 33 GeV impinge upon a Tantalum/Tungsten target, producing showers of positrons with energies extending from approximately 2 to 20 MeV, with most positrons at the low end of this range. Positrons with low energies and finite transverse momenta slip phase during the processes of reacceleration and reinjection into the SLC system, increasing the energy spread and reducing the overall yield of the positron source. This reduction in yield has to be minimized by ''capturing'' the positrons with a high-field accelerator section placed as soon after the target as possible. The design, fabrication and RF testing of this accelerator section are described.

  19. PREFACE: The 16th International Conference on Positron Annihilation (ICPA-16)

    NASA Astrophysics Data System (ADS)

    Alam, Ashraf; Coleman, Paul; Dugdale, Stephen; Roussenova, Mina

    2013-06-01

    The 16th International Conference on Positron Annihilation (ICPA-16) was held at the University of Bristol, United Kingdom during 19-24 August, 2012. This triennial conference is the foremost gathering of the Positron Annihilation Physics community and it was hosted in the UK for the first time since the series of meetings first started back in 1965. The University of Bristol, the Alma Mater of Paul Dirac, is situated at the heart of the city, and it has established a worldwide reputation in research and teaching. Many of the topics which were discussed during ICPA-16 form an integral part of the research themes in the schools of Physics, Chemistry and Engineering of this University. ICPA-16 attracted a diverse audience, both from academic and industrial institutions, with over 200 participants from 29 countries. It continued the long held tradition of showcasing novel research in the field of positron annihilation and a total of 170 papers were presented as talks and posters. The papers reported studies of metallic and semi-conducting solids, polymers and soft matter, porous materials, surfaces and interfaces, as well as advances in experimental, analytical and biomedical applications. The high quality of the presented work, coupled with the enthusiastic exchange of ideas, provided an invaluable forum, especially for younger researchers and postgraduate students. The excellence of student presentations was acknowledged by the award of prizes for the best student posters, which were received by David Billington (University of Bristol, UK), Moussa Sidibe (CEMHTI, France) and Hongxia Xu (Tohoku University, Japan). All papers published in the Conference Proceedings were reviewed by ICPA-16 participants. We are indebted to all reviewers who contributed their time and intellectual resources, allowing the refereeing and editing process to move smoothly toward the compilation of the Proceedings. Our sincere thanks and gratitude go to everyone who contributed to the

  20. A General Quantum Mechanical Method to Predict Positron Spectroscopy

    DTIC Science & Technology

    2007-06-01

    70 6.2.3 Positronic Systems for Modeling and Experiment 71 Appendix A. Electron-Positron Annihilation Observables from NEO-HF and NEO-MP2...spectroscopy (PAS) experiments are widely used to study materials defects, including point defects in semiconductors and voids in composite materials...addition to traditional PAS techniques, experiments involving VFRs are also discussed. In Section 2.2, methods for modeling positron interaction with

  1. Positron Annihilation Studies In Polymer Nano-Composites

    SciTech Connect

    Chen, H. M.; Awad, Somia; Jean, Y. C.; Yang, J.; Lee, L. James

    2011-06-01

    Positron annihilation spectroscopy coupled with a variable mono-energy positron beam has been applied to study nanoscale polymeric nanocomposites. New information about multilayer depth profiles and structures, interfacial free-volume and open space properties have been obtained in polystyrene/carbon nano fiber composites. The S parameter in Doppler Broadening Energy Spectra combined slow positron beam is used to quantitatively represent the free volume, open spaces, and interactions in the interface between polystyrene matrix and carbon nanofibers.

  2. Detecting positron-atom bound states through resonant annihilation.

    PubMed

    Dzuba, V A; Flambaum, V V; Gribakin, G F

    2010-11-12

    A method is proposed for detecting positron-atom bound states by observing enhanced positron annihilation due to electronic Feshbach resonances at electron-volt energies. The method is applicable to a range of open-shell transition-metal atoms which are likely to bind the positron: Fe, Co, Ni, Tc, Ru, Rh, Sn, Sb, Ta, W, Os, Ir, and Pt. Estimates of their binding energies are provided.

  3. On the localization of positrons in metal vacancies

    NASA Astrophysics Data System (ADS)

    Babich, A. V.; Pogosov, V. V.; Reva, V. I.

    2015-11-01

    The probability of localization of positrons in single vacancies of Al, Cu, and Zn as a function of temperature has been calculated. Vacancy has been simulated by a cavity with a radius of the Wigner-Seitz cell in the stabilized jellium model. A formula for the rate of trapping of a positron by a vacancy as a function of the positron energy has been obtained using the "golden" rule for transitions under the assumption that the positron energy is spent on excitation of electron-hole pairs. The temperature dependence of the localization rate has been calculated for thermalized positrons. It has been found that, in the vicinity of the triple point, the localization rate is close in order of magnitude to the annihilation rate. Based on the results reported in our previous publications devoted to the evaluation of the influence of vacancies on the work function of free positrons, it has been assumed that, near the surface of the metal, there are vacancies charged by positrons. In the approximation of a two-dimensional superlattice, the near-surface vacancy barrier has been estimated. The experimentally revealed shift of the energy distribution of re-emitted positrons has been assumed to be caused by the reflection of low-energy positrons from the vacancy barrier back into the bulk of the metal where they annihilate.

  4. Sensitivity of positron annihilation to hydrogen in Zr

    SciTech Connect

    Hood, G.M.; Schultz, R.J.

    1982-01-01

    Positron annihilation spectroscopy has been applied to the quantitative determination of hydrogen in zirconium. The sensitivity of the positron annihilation was noted to be influenced not only by the presence of hydrogen but also by the heat treatment of the hydrided samples. The positron is attracted to the relatively negative, or ion-core-deficient regions of the metal, F regions commonly associated with vacancies, voids and dislocations. It was found to be very difficult to gauge the relative effects which hydrides and dislocations might have on the positron annihilation in zirconium. (BLM)

  5. Positron-molecule bound states and positive ion production

    NASA Technical Reports Server (NTRS)

    Leventhal, M.; Passner, A.; Surko, C. M.

    1990-01-01

    The interaction was studied of low energy positrons with large molecules such as alkanes. These data provide evidencce for the existence of long lived resonances and bound states of positrons with neutral molecules. The formation process and the nature of these resonances are discussed. The positive ions produced when a positron annihilates with an electron in one of these resonances were observed and this positive ion formation process is discussed. A review is presented of the current state of the understanding of these positron-molecule resonances and the resulting positive ion formation. A number of outstanding issues in this area is also discussed.

  6. What is the fate of runaway positrons in tokamaks?

    DOE PAGES

    Liu, Jian; Qin, Hong; Fisch, Nathaniel J.; ...

    2014-06-19

    In this study, massive runaway positrons are generated by runaway electrons in tokamaks. The fate of these positrons encodes valuable information about the runaway dynamics. The phase space dynamics of a runaway position is investigated using a Lagrangian that incorporates the tokamak geometry, loop voltage, radiation and collisional effects. It is found numerically that runaway positrons will drift out of the plasma to annihilate on the first wall, with an in-plasma annihilation possibility less than 0.1%. The dynamics of runaway positrons provides signatures that can be observed as diagnostic tools.

  7. Search for a positron anisotropy with PAMELA experiment

    NASA Astrophysics Data System (ADS)

    Panico, B.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Castellini, G.; De Donato, C.; De Santis, C.; De Simone, N.; Di Felice, V.; Formato, V.; Galper, A. M.; Giaccari, U.; Karelin, A. V.; Koldashov, S. V.; Koldobskiy, S.; Krutkov, S. Y.; Kvashnin, A. N.; Leonov, A.; Malakhov, V.; Marcelli, L.; Martucci, M.; Mayorov, A. G.; Menn, W.; Mergé, M.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Munini, R.; Osteria, G.; Palma, F.; Pearce, M.; Picozza, P.; Ricci, M.; Ricciarini, S. B.; Sarkar, R.; Scotti, V.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, G. I.; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.

    2015-09-01

    The PAMELA experiment has been collecting data since 2006; its results indicate a rise in the positron fraction with respect to the sum of electrons and positrons in the cosmic-ray (CR) spectrum above 10 GeV. This excess can be due to additional sources, as SNRs or pulsars, which can lead to an anisotropy in the local CR positron, detectable from current experiments. We report on the analysis on spatial distributions of positron events collected by PAMELA, taking into account also the geomagnetic field effects. No significant deviation from the isotropy has been observed.

  8. Recent Developments in the Design of the NLC Positron Source

    SciTech Connect

    Kotseroglou, T.; Bharadwaj, V.; Clendenin, J.E.; Ecklund, S,; Frisch, J.; Krejcik, P,; Kukikov, A.V.; Liu, J.; Maruyama, T.; Millage, K.K.; Mulhollan, G.; Nelson, W.R.; Schultz, D.C.; Sheppard, J.C.; Turner, J.; Van Bibber, K.; Flottmann, K.; Namito, Y.

    1999-11-05

    Recent developments in the design of the Next Linear Collider (NLC) positron source based on updated beam parameters are described. The unpolarized NLC positron source [1,2] consists of a dedicated 6.2 GeV S-band electron accelerator, a high-Z positron production target, a capture system and an L-band positron linac. The 1998 failure of the SLC target, which is currently under investigation, may lead to a variation of the target design. Progress towards a polarized positron source is also presented. A moderately polarized positron beam colliding with a highly polarized electron beam results in an effective polarization large enough to explore new physics at NLC. One of the schemes towards a polarized positron source incorporates a polarized electron source, a 50 MeV electron accelerator, a thin target for positron production and a new capture system optimized for high-energy, small angular-divergence positrons. The yield for such a process, checked using the EGS4 code, is of the order of 10{sup -3}. The EGS4 code has being enhanced to include the effect of polarization in bremsstrahlung and pair-production process.

  9. Another Nobel Prize linked to synchrotron radiation work

    SciTech Connect

    Hasnain, S.

    2009-01-01

    The 2008 Nobel Prize in Chemistry went to Osamu Shimomura, Martin Chalfie and Roger Tsien 'for the discovery and development of the green fluorescent protein, GFP'. This year's Nobel Prize in Chemistry rewards the initial discovery of GFP and a series of important developments which have led to its use as a tagging tool in bioscience. By using DNA technology, researchers can now connect GFP to other interesting, but otherwise invisible, proteins. This glowing marker allows the movements, positions and interactions of the tagged proteins to be monitored. Osamu Shimomura was the first to isolate GFP from the jellyfish Aequorea victoria, found off the west coast of North America, and discovered the protein's green glow [Shimomura et al. (1962). J. Cell. Comp. Physiol. 59, 223-240]. Martin Chalfie demonstrated the value of GFP as a luminous genetic tag. In one of his first experiments he coloured six individual cells in the transparent roundworm Caenorhabditis elegans with the aid of GFP. He had obtained the GFP gene (gfp) clone from Prasher [Prasher et al. (1992). Gene, 111, 229-233] and expressed it in E. coli. The GFP protein displayed a bright green fluorescence in this heterologous organism, suggesting that it could indeed serve as a versatile genetic marker in virtually all organisms. Chalfie transformed C. elegans with gfp under the control of a promoter regulating the expression of {beta}-tubulin, abundant in six touch receptor neurons in C. elegans. The organism subsequently expressed GFP from distinct positions in its body and at distinct times in its development [Chalfie et al. (1994). Science, 263, 802-805]. Roger Tsien contributed to the general understanding of how GFP glows by determining the formation of the GFP chromophore, a chemical group that absorbs and emits light. Tsien is best known for extending the colour palette of GFP beyond green, allowing researchers to follow several different biological processes at the same time. According to background

  10. FETTU Wins International Year of Astronomy 2009 Prize

    NASA Astrophysics Data System (ADS)

    2010-02-01

    The "From Earth to the Universe" (FETTU) project -- a worldwide series of exhibitions featuring striking astronomical imagery -- has won the first Mani Bhaumik prize for excellence in astronomy education and public outreach. This award was given for the best of the tens of thousands of activities conducted during the International Year of Astronomy (IYA) 2009. NASA was a major sponsor of the project, which was led by the Chandra X-ray Center, that placed these images into public parks, metro stations, libraries, and other non-traditional locations around the world. The exhibit showcases some of the best astronomical images taken from telescopes both on the ground and in space, representing the wide variety of wavelengths and objects observed. While FETTU has been a worldwide effort, a NASA grant provided the primary funding for the FETTU exhibits in the US. NASA funds also supplied the project's infrastructure as well as educational and other materials that helped the FETTU international efforts to thrive. "We are truly thrilled to see how many people FETTU has reached both in the US and around the world," said Hashima Hasan, NASA's Single Point of Contact for IYA2009. "It's an investment we feel has been well spent." In the US, FETTU has been placed on semi-permanent display at Chicago's O'Hare and Atlanta's Hartsfield airports. In addition, a traveling version of the exhibit has visited over a dozen US cities such as Washington, DC, Anchorage, AK, Memphis, TN, and New York City. Three tactile and Braille versions of the FETTU exhibit were also made possible by the NASA funds, each of which has traveled to multiple locations around the country. "It's been so rewarding to see how people - many of whom had never seen these images - have embraced the wonders of astronomy through these exhibits," said Kimberly Kowal Arcand, co-chair of the FETTU project at the Chandra X-ray Center, which is located at the Smithsonian Astrophysical Observatory in Cambridge, Mass. "The

  11. [Commentary on the Nobel Prize that has been granted in Medicine-Physiology, Chemistry and Physics to noteable investigators].

    PubMed

    Zárate, Arturo; Apolinar, Leticia Manuel; Saucedo, Renata; Basurto, Lourdes

    2015-01-01

    The Nobel Prize was established by Alfred Nobel in 1901 to award people who have made outstanding achievements in physics, chemistry and medicine. So far, from 852 laureates, 45 have been female. Marie Curie was the first woman to receive the Nobel Prize in 1903 for physics and eight years later also for chemistry It is remarkable that her daughter Irene and her husband also received the Nobel Prize for chemistry in 1935. Other two married couples, Cori and Moser, have also been awarded the Nobel Prize. The present commentary attempts to show the female participation in the progress of scientific activities.

  12. Probing the positron moderation process using high-intensity, highly polarized slow-positron beams

    NASA Technical Reports Server (NTRS)

    Van House, J.; Zitzewitz, P. W.

    1984-01-01

    A highly polarized (P = 0.48 + or - 0.02) intense (500,000/sec) beam of 'slow' (Delta E = about 2 eV) positrons (e+) is generated, and it is shown that it is possible to achieve polarization as high as P = 0.69 + or - 0.04 with reduced intensity. The measured polarization of the slow e+ emitted by five different positron moderators showed no dependence on the moderator atomic number (Z). It is concluded that only source positrons with final kinetic energy below 17 keV contribute to the slow-e+ beam, in disagreement with recent yield functions derived from low-energy measurements. Measurements of polarization and yield with absorbers of different Z between the source and moderator show the effects of the energy and angular distributions of the source positrons on P. The depolarization of fast e+ transmitted through high-Z absorbers has been measured. Applications of polarized slow-e+ beams are discussed.

  13. Nobel Prize Literature; A Selection of the Works of Forty-Four Nobel Prize Winning Authors in the Library of Dutchess Community College, with Biographical and Critical Sketches.

    ERIC Educational Resources Information Center

    Hubbard, Terry E., Comp.

    This bibliography is a compilation of works by 44 Nobel Prize winning authors presently available at the Dutchess Community College library. Each entry describes the piece of literature for which the author received an award, provides a brief sketch of the writer, includes a commentary on the themes of major works, and lists the writer's works. An…

  14. Positron impact ionization of atomic hydrogen

    SciTech Connect

    Acacia, P.; Campeanu, R.I.; Horbatsch, M.

    1993-05-01

    We will present integrated cross sections for ionization of atomic hydrogen by positrons. These have been calculated in a distorted-wave approximation using energy-dependent effective charges in the final channel as well as static and polarization potentials in the initial channel. We present two models for calculating the energy-dependent effective charges both of which produce results in good agreement with the recent experimental measurements of Spicher et al. This is in contrast to previous distorted-wave calculations which used fixed effective charges as well as classical trajectory calculations. Both of these latter methods produced results which were substantially below ours and the experimental data.

  15. Possible resonance in positron-lithium scattering

    NASA Astrophysics Data System (ADS)

    Abdel-Raouf, M. A.; Wood, R. F.

    1990-09-01

    The possible appearance of resonances in the partial cross sections of the inelastic collisions of positrons with lithium atoms at energies below 5 eV is investigated. It is assumed that only elastic and rearrangement channels are open, while excitation channels are closed. A coupled static formalism, in which the polarization potentials of the lithium and positronium are switched on, is employed. The basis set of Clementi and Roetti [At. Data Nucl. Data Tables 14, 177 (1974)] is used for describing the target model. Comparison between the resulting total cross sections and those obtained by other authors is presented.

  16. Positron autoradiography for intravascular imaging: feasibility evaluation.

    PubMed

    Shikhaliev, Polad M; Xu, Tong; Ducote, Justin L; Easwaramoorthy, Balasubramaniam; Mukherjee, Jogeshwar; Molloi, Sabee

    2006-02-21

    Approximately 70% of acute coronary artery disease is caused by unstable (vulnerable) plaques with an inflammation of the overlying cap and high lipid content. A rupturing of the inflamed cap of the plaque results in propagation of the thrombus into the lumen, blockage of the artery and acute ischaemic syndrome or sudden death. Morphological imaging such as angiography or intravascular ultrasound cannot determine inflammation status of the plaque. A radiotracer such as 18F-FDG is accumulated in vulnerable plaques due to higher metabolic activity of the inflamed cap and could be used to detect a vulnerable plaque. However, positron emission tomography (PET) cannot detect the FDG-labelled plaques because of respiratory and heart motions, small size and low activity of the plaques. Plaques can be detected using a miniature particle (positron) detector inserted into the artery. In this work, a new detector concept is investigated for intravascular imaging of the plaques. The detector consists of a storage phosphor tip bound to the end of an intravascular catheter. It can be inserted into an artery, absorb the 18F-FDG positrons from the plaques, withdrawn from the artery and read out. Length and diameter of the storage phosphor tip can be matched to the length and the diameter of the artery. Monte Carlo simulations and experimental evaluations of coronary plaque imaging with the proposed detector were performed. It was shown that the sensitivity of the storage phosphor detector to the positrons of 18F-FDG is sufficient to detect coronary plaques with 1 mm and 2 mm sizes and 590 Bq and 1180 Bq activities in the arteries with 2 mm and 3 mm diameters, respectively. An experimental study was performed using plastic tubes with 2 mm diameter filled with an FDG solution, which simulates blood. FDG spots simulating plaques were placed over the surface of the tube. A phosphor tip was inserted into the tube and imaged the plaques. Exposure time was 1 min in all simulations and

  17. Positron emission tomography (PET) for cholangiocarcinoma

    PubMed Central

    Breitenstein, S.; Apestegui, C.

    2008-01-01

    The combination of positron emission tomography (PET) with computed tomography (PET-CT) provides simultaneous metabolic and anatomic information on tumors in the same imaging session. Sensitivity of PET/PET-CT is higher for intrahepatic (>90%) than for extrahepatic cholangiocarcinoma (CCA) (about 60%). The detection rate of distant metastasis is 100%. PET, and particularly PET-CT, improves the results and impacts on the oncological management in CCA compared with other imaging modalities. Therefore, PET-CT is recommended in the preoperative staging of intrahepatic (strength of recommendation: moderate) and extrahepatic (strength of recommendation: low) CCA. PMID:18773069

  18. DHCAL with minimal absorber: measurements with positrons

    NASA Astrophysics Data System (ADS)

    Freund, B.; Neubüser, C.; Repond, J.; Schlereth, J.; Xia, L.; Dotti, A.; Grefe, C.; Ivantchenko, V.; Berenguer Antequera, J.; Calvo Alamillo, E.; Fouz, M.-C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Brianne, E.; Ebrahimi, A.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Irles, A.; Krivan, F.; Krüger, K.; Kvasnicka, J.; Lu, S.; Lutz, B.; Morgunov, V.; Provenza, A.; Reinecke, M.; Sefkow, F.; Schuwalow, S.; Tran, H. L.; Garutti, E.; Laurien, S.; Matysek, M.; Ramilli, M.; Schroeder, S.; Bilki, B.; Norbeck, E.; Northacker, D.; Onel, Y.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kovalcuk, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; van Doren, B.; Wilson, G. W.; Kawagoe, K.; Hirai, H.; Sudo, Y.; Suehara, T.; Sumida, H.; Takada, S.; Tomita, T.; Yoshioka, T.; Bilokin, S.; Bonis, J.; Cornebise, P.; Pöschl, R.; Richard, F.; Thiebault, A.; Zerwas, D.; Hostachy, J.-Y.; Morin, L.; Besson, D.; Chadeeva, M.; Danilov, M.; Markin, O.; Popova, E.; Gabriel, M.; Goecke, P.; Kiesling, C.; van der Kolk, N.; Simon, F.; Szalay, M.; Corriveau, F.; Blazey, G. C.; Dyshkant, A.; Francis, K.; Zutshi, V.; Kotera, K.; Ono, H.; Takeshita, T.; Ieki, S.; Kamiya, Y.; Ootani, W.; Shibata, N.; Jeans, D.; Komamiya, S.; Nakanishi, H.

    2016-05-01

    In special tests, the active layers of the CALICE Digital Hadron Calorimeter prototype, the DHCAL, were exposed to low energy particle beams, without being interleaved by absorber plates. The thickness of each layer corresponded approximately to 0.29 radiation lengths or 0.034 nuclear interaction lengths, defined mostly by the copper and steel skins of the detector cassettes. This paper reports on measurements performed with this device in the Fermilab test beam with positrons in the energy range of 1 to 10 GeV. The measurements are compared to simulations based on GEANT4 and a standalone program to emulate the detailed response of the active elements.

  19. Positron Scanner for Locating Brain Tumors

    DOE R&D Accomplishments Database

    Rankowitz, S.; Robertson, J. S.; Higinbotham, W. A.; Rosenblum, M. J.

    1962-03-01

    A system is described that makes use of positron emitting isotopes for locating brain tumors. This system inherently provides more information about the distribution of radioactivity in the head in less time than existing scanners which use one or two detectors. A stationary circular array of 32 scintillation detectors scans a horizontal layer of the head from many directions simultaneously. The data, consisting of the number of counts in all possible coincidence pairs, are coded and stored in the memory of a Two-Dimensional Pulse-Height Analyzer. A unique method of displaying and interpreting the data is described that enables rapid approximate analysis of complex source distribution patterns. (auth)

  20. Positron autoradiography for intravascular imaging: feasibility evaluation

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.; Xu, Tong; Ducote, Justin L.; Easwaramoorthy, Balasubramaniam; Mukherjee, Jogeshwar; Molloi, Sabee

    2006-02-01

    Approximately 70% of acute coronary artery disease is caused by unstable (vulnerable) plaques with an inflammation of the overlying cap and high lipid content. A rupturing of the inflamed cap of the plaque results in propagation of the thrombus into the lumen, blockage of the artery and acute ischaemic syndrome or sudden death. Morphological imaging such as angiography or intravascular ultrasound cannot determine inflammation status of the plaque. A radiotracer such as 18F-FDG is accumulated in vulnerable plaques due to higher metabolic activity of the inflamed cap and could be used to detect a vulnerable plaque. However, positron emission tomography (PET) cannot detect the FDG-labelled plaques because of respiratory and heart motions, small size and low activity of the plaques. Plaques can be detected using a miniature particle (positron) detector inserted into the artery. In this work, a new detector concept is investigated for intravascular imaging of the plaques. The detector consists of a storage phosphor tip bound to the end of an intravascular catheter. It can be inserted into an artery, absorb the 18F-FDG positrons from the plaques, withdrawn from the artery and read out. Length and diameter of the storage phosphor tip can be matched to the length and the diameter of the artery. Monte Carlo simulations and experimental evaluations of coronary plaque imaging with the proposed detector were performed. It was shown that the sensitivity of the storage phosphor detector to the positrons of 18F-FDG is sufficient to detect coronary plaques with 1 mm and 2 mm sizes and 590 Bq and 1180 Bq activities in the arteries with 2 mm and 3 mm diameters, respectively. An experimental study was performed using plastic tubes with 2 mm diameter filled with an FDG solution, which simulates blood. FDG spots simulating plaques were placed over the surface of the tube. A phosphor tip was inserted into the tube and imaged the plaques. Exposure time was 1 min in all simulations and

  1. Liquid Metal Target for NLC Positron Source

    SciTech Connect

    Sheppard, John C.

    2002-08-19

    Possibility of creating the liquid lead target with parameters, optimum for the NLC positron source, is investigated. Target has a form of titanium vessel, filled with liquid lead, pumped through. The energy deposition in target is characterized by 35 kW average power and up to 250 J/g specific energy at optimum beam sigma 0.6 mm. The use of pumped through liquid lead as target material solves both the problems of power evacuation and target survival. The window for beam exit is made of both temperature and pressure resistive material--the diamond-like ceramic BN.

  2. Positron Emission Tomography: Its 65 years

    NASA Astrophysics Data System (ADS)

    Del Guerra, A.; Belcari, N.; Bisogni, M.

    2016-04-01

    Positron Emission Tomography (PET) is a well-established imaging technique for in vivo molecular imaging. In this review after a brief history of PET there are presented its physical principles and the technology that has been developed for bringing PET from a bench experiment to a clinical indispensable instrument. The limitations and performance of the PET tomographs are discussed, both as for the hardware and software aspects. The status of art of clinical, pre-clinical and hybrid scanners (, PET/CT and PET/MR) is reported. Finally the actual trend and the recent and future technological developments are fully illustrated.

  3. EPA Employee Selected as Winner of 2015 Service to America Medal/Cookstoves initiative improving lives of millions by reducing indoor smoke exposure

    EPA Pesticide Factsheets

    WASHINGTON - Today, the Partnership for Public Service selected Jacob Moss as winner of one of the most prestigious 2015 Samuel J. Heyman Service to America Medals (Sammies), which highlight America's dedicated federal workers who have made significa

  4. Algenol in Fort Myers, Fla. Among Winners of the 20th Annual Presidential Green Chemistry Challenge Awards/Innovative technologies tackle climate change, water, and chemical issues

    EPA Pesticide Factsheets

    ATLANTA - Algenol in Fort Myers, Florida is among the winners to be recognized by the U.S. Environmental Protection Agency (EPA) for landmark green chemistry technologies developed by industrial pioneers and leading scientists that turn climate risk

  5. Applications of positron annihilation spectroscopy in materials research

    NASA Technical Reports Server (NTRS)

    Singh, Jag J.

    1988-01-01

    Positron Annihilation Spectroscopy (PAS) has emerged as a powerful technique for research in condensed matter. It has been used extensively in the study of metals, ionic crystals, glasses and polymers. The present review concentrates on applications of positron lifetime measurements for elucidation of the physicochemical structure of polymers.

  6. Towards laboratory produced relativistic electron–positron pair plasmas

    SciTech Connect

    Chen, Hui; Meyerhofer, D. D.; Wilks, S. C.; Cauble, R.; Dollar, F.; Falk, K.; Gregori, G.; Hazi, A.; Moses, E. I.; Murphy, C. D.; Myatt, J.; Park, J.; Seely, J.; Shepherd, R.; Spitkovsky, A.; Stoeckl, C.; Szabo, C. I.; Tommasini, R.; Zulick, C.; Beiersdorfer, P.

    2011-12-01

    We review recent experimental results on the path to producing electron–positron pair plasmas using lasers. Relativistic pair-plasmas and jets are believed to exist in many astrophysical objects and are often invoked to explain energetic phenomena related to Gamma Ray Bursts and Black Holes. On earth, positrons from radioactive isotopes or accelerators are used extensively at low energies (sub-MeV) in areas related to surface science positron emission tomography and basic antimatter science. Experimental platforms capable of producing the high-temperature pair-plasma and high-flux jets required to simulate astrophysical positron conditions have so far been absent. In the past few years, we performed extensive experiments generating positrons with intense lasers where we found that relativistic electron and positron jets are produced by irradiating a solid gold target with an intense picosecond laser pulse. The positron temperatures in directions parallel and transverse to the beam both exceeded 0.5 MeV, and the density of electrons and positrons in these jets are of order 1016 cm-3 and 1013 cm-3, respectively. With the increasing performance of high-energy ultra-short laser pulses, we expect that a high-density, up to 1018 cm-3, relativistic pair-plasma is achievable, a novel regime of laboratory-produced hot dense matter.

  7. Recent Developments in Positron Emission Tomography (PET) Instrumentation

    DOE R&D Accomplishments Database

    Derenzo, S. E.; Budinger, T. F.

    1986-04-01

    This paper presents recent detector developments and perspectives for positron emission tomography (PET) instrumentation used for medical research, as well as the physical processes in positron annihilation, photon scattering and detection, tomograph design considerations, and the potentials for new advances in detectors.

  8. Positron-annihilation study of radiation defects in sodium azide

    SciTech Connect

    Etin, G.I.; Ryabykh, S.M.

    1987-07-01

    Annihilation-photon angular correlation has been used to examine radiation defects in sodium azide capable of trapping positrons. The calculated and measured characteristics have been determined for various defects, including micropores filled by radiolytic nitrogen. The positron annihilation rates have been determined for the regions around radiation defects.

  9. Moisture determination in composite materials using positron lifetime techniques

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Holt, W. R.; Mock, W., Jr.

    1980-01-01

    A technique was developed which has the potential of providing information on the moisture content as well as its depth in the specimen. This technique was based on the dependence of positron lifetime on the moisture content of the composite specimen. The positron lifetime technique of moisture determination and the results of the initial studies are described.

  10. Formation of a high intensity low energy positron string

    NASA Astrophysics Data System (ADS)

    Donets, E. D.; Donets, E. E.; Syresin, E. M.; Itahashi, T.; Dubinov, A. E.

    2004-05-01

    The possibility of a high intensity low energy positron beam production is discussed. The proposed Positron String Trap (PST) is based on the principles and technology of the Electron String Ion Source (ESIS) developed in JINR during the last decade. A linear version of ESIS has been used successfully for the production of intense highly charged ion beams of various elements. Now the Tubular Electron String Ion Source (TESIS) concept is under study and this opens really new promising possibilities in physics and technology. In this report, we discuss the application of the tubular-type trap for the storage of positrons cooled to the cryogenic temperatures of 0.05 meV. It is intended that the positron flux at the energy of 1-5 eV, produced by the external source, is injected into the Tubular Positron Trap which has a similar construction as the TESIS. Then the low energy positrons are captured in the PST Penning trap and are cooled down because of their synchrotron radiation in the strong (5-10 T) applied magnetic field. It is expected that the proposed PST should permit storing and cooling to cryogenic temperature of up to 5×109 positrons. The accumulated cooled positrons can be used further for various physics applications, for example, antihydrogen production.

  11. A Simple Estimate of the Mass of the Positron.

    ERIC Educational Resources Information Center

    Jones, Goronwy Tudor

    1993-01-01

    Discusses a small part of the final state of a high-energy neutrino interaction: a head-on collision of a positron and a stationary electron. Provides a bubble chamber picture and describes the resulting particle effects. Uses momentum to determine the mass of the positron. (MVL)

  12. Monte Carlo modelling of positron transport in real world applications

    NASA Astrophysics Data System (ADS)

    Marjanović, S.; Banković, A.; Šuvakov, M.; Petrović, Z. Lj

    2014-05-01

    Due to the unstable nature of positrons and their short lifetime, it is difficult to obtain high positron particle densities. This is why the Monte Carlo simulation technique, as a swarm method, is very suitable for modelling most of the current positron applications involving gaseous and liquid media. The ongoing work on the measurements of cross-sections for positron interactions with atoms and molecules and swarm calculations for positrons in gasses led to the establishment of good cross-section sets for positron interaction with gasses commonly used in real-world applications. Using the standard Monte Carlo technique and codes that can follow both low- (down to thermal energy) and high- (up to keV) energy particles, we are able to model different systems directly applicable to existing experimental setups and techniques. This paper reviews the results on modelling Surko-type positron buffer gas traps, application of the rotating wall technique and simulation of positron tracks in water vapor as a substitute for human tissue, and pinpoints the challenges in and advantages of applying Monte Carlo simulations to these systems.

  13. Electrons and positrons from expanding supernova envelopes in dense clouds

    NASA Technical Reports Server (NTRS)

    Stephens, S. A.

    1985-01-01

    If antiprotons in cosmic rays are produced as secondary particles in sources, it is expected that positrons are also created by the same process. The interstellar spectra of positrons and electrons are calculated by taking into account such sources. Spectra are then compared with observations.

  14. Recent developments in positron emission tomography (PET) instrumentation

    SciTech Connect

    Derenzo, S.E.; Budinger, T.F.

    1986-04-01

    This paper presents recent detector developments and perspectives for positron emission tomography (PET) instrumentation used for medical research, as well as the physical processes in positron annihilation, photon scattering and detection, tomograph design considerations, and the potentials for new advances in detectors. 117 refs., 4 figs., 4 tabs.

  15. Postcontest blockade of dopamine receptors inhibits development of the winner effect in the California mouse (Peromyscus californicus).

    PubMed

    Becker, Elizabeth A; Marler, Catherine A

    2015-04-01

    The winner effect is an accumulation of previous wins that increase future winning. A primary unanswered question about the winner effect is how do individuals integrate information about previous wins? Dopamine (DA) has been implicated because phosphorylated tyrosine hydroxylase (pTH), the rate-limiting enzyme for DA biosynthesis, is elevated following multiple winning experiences. Moreover, DA receptor blockers and agonists influence aggression when administered prior to male-male contests. In the current study, we administered D1- and D2-like DA receptor antagonists immediately after a contest and examined the development of the winner effect in the territorial California mouse, Peromyscus californicus. During a 3-contest training phase, resident males experienced winning contests, followed immediately by a peripheral injection of either a DA receptor antagonist or vehicle or a handling experience (without injection). The DA receptor antagonists used in this study did not influence locomotion. To assess the cumulative effects of previous winning, males were subjected to a final test contest with a more competitive intruder. The winner effect was significantly decreased by both D1- and D2-like receptor antagonists administered during training. During the test contest, attack behavior was significantly reduced by previous administration of both types of DA receptor antagonists compared with controls. D1-like receptor blockade also diminished chasing behavior, whereas D2-antagonist treated animals continued to pursue opponents. During training against a less competitive intruder, there was no difference in aggressive behaviors between experimental and controls males. Our data indicate that DA activity between contests is concomitant with the competitive advantage gained from multiple winning experiences.

  16. Independent and additive contributions of postvictory testosterone and social experience to the development of the winner effect.

    PubMed

    Fuxjager, Matthew J; Oyegbile, Temitayo O; Marler, Catherine A

    2011-09-01

    The processes through which salient social experiences influence future behavior are not well understood. Winning fights, for example, can increase the odds of future victory, yet little is known about the internal mechanisms that underlie such winner effects. Here, we use the territorial California mouse (Peromyscus californicus) to investigate how the effects of postvictory testosterone (T) release and winning experience individually mediate positive changes in future winning ability and antagonistic behavior. Male mice were castrated and implanted with T capsules to maintain basal levels of this hormone. We found that males form a robust winner effect if they win three separate territorial disputes and experience a single T surge roughly 45 min after each encounter. Meanwhile, males exhibit only an intermediate winner effect if they either 1) acquire three previous wins but do not experience a change in postvictory T or 2) acquire no previous wins but experience three separate T pulses. The results indicate that the effect of postvictory T must be coupled with that of winning experience to trigger the maximum positive shift in winning ability, which highlights the importance of social context in the development of the winner effect. At the same time, however, postvictory T and winning experience are each capable of increasing future winning ability independently, and this finding suggests that these two factors drive plasticity in antagonistic behavior via distinct mechanistic channels. More broadly, our data offer insight into the possible ways in which various species might be able to adjust their behavioral repertoire in response to social interactions through mechanisms that are unlinked from the effects of gonadal steroid action.

  17. Winners, losers, and posers: The effect of power poses on testosterone and risk-taking following competition.

    PubMed

    Smith, Kristopher M; Apicella, Coren L

    2016-11-10

    A contribution to a special issue on Hormones and Human Competition. The effect of postural power displays (i.e. power poses) on hormone levels and decision-making has recently been challenged. While Carney et al. (2010) found that holding brief postural displays of power leads to increased testosterone, decreased cortisol and greater economic risk taking, this failed to replicate in a recent high-powered study (Ranehill et al. 2015). It has been put forward that subtle differences in social context may account for the differences in results. Power displays naturally occur within the context of competitions, as do changes in hormones, and researchers have yet to examine the effects of poses within this ecologically relevant context. Using a large sample of 247 male participants, natural winners and losers of a physical competition were randomly assigned to hold a low, neutral or high-power postural display. We found no main effect of pose type on testosterone, cortisol, risk or feelings of power. Winners assigned to a high-power pose had a relative, albeit small, rise in testosterone compared to winners who held neutral or low-power poses. For losers, we found little evidence that high-power poses lead to increased testosterone relative to those holding neutral or low-powered poses. If anything, the reverse was observed - losers had a reduction in testosterone after holding high-power poses. To the extent that changes in testosterone modulate social behaviors adaptively, it is possible that the relative reduction in testosterone observed in losers taking high-powered poses is designed to inhibit further "winner-like" behavior that could result in continued defeat and harm. Still, effects were small, multiple comparisons were made, and the results ran counter to our predictions. We thus treat these conclusions as preliminary.

  18. First positron annihilation lifetime measurement of Pu

    SciTech Connect

    Colmenares, C.; Howell, R.H.; Ancheta, D.; Cowan, T.; Hanafee, J.; Sterne, P.

    1996-11-21

    We have made the first measurement of defects in an aged sample of {delta} phase, Ga stabilized Pu, using positron annihilation lifetime spectroscopy. This measurement validates the procedure necessary to perform measurements on this highly toxic material and obtain data representative of sample conditions. Comparison of the positron annihilation lifetime analysis of the data with calculated values suggests that He filled vacancies or vacancy clusters dominate the defect population. Such defects are the necessary precursor to void growth and swelling. The evolution of defects resulting from the radioactive decay of Pu during its life in the stockpile is one of the unknown quantities affecting our confidence in predictions of the limit on stockpile components. Radiation damage leads to changes in the size and strength of metals studied for reactor and accelerator use and similar effects may be expected in Pu. The evolution of radiation produced vacancies into larger void structures and accompanying macroscopic swelling may occur in Pu at some age. A detailed understanding of the defects in self irradiated Pu is required to predict the time scale of void swelling and related radiation effects. 1 fig.

  19. Analysis of positron lifetime spectra in polymers

    NASA Technical Reports Server (NTRS)

    Singh, Jag J.; Mall, Gerald H.; Sprinkle, Danny R.

    1988-01-01

    A new procedure for analyzing multicomponent positron lifetime spectra in polymers was developed. It requires initial estimates of the lifetimes and the intensities of various components, which are readily obtainable by a standard spectrum stripping process. These initial estimates, after convolution with the timing system resolution function, are then used as the inputs for a nonlinear least squares analysis to compute the estimates that conform to a global error minimization criterion. The convolution integral uses the full experimental resolution function, in contrast to the previous studies where analytical approximations of it were utilized. These concepts were incorporated into a generalized Computer Program for Analyzing Positron Lifetime Spectra (PAPLS) in polymers. Its validity was tested using several artificially generated data sets. These data sets were also analyzed using the widely used POSITRONFIT program. In almost all cases, the PAPLS program gives closer fit to the input values. The new procedure was applied to the analysis of several lifetime spectra measured in metal ion containing Epon-828 samples. The results are described.

  20. Positron Emission Tomography: A Basic Analysis

    NASA Astrophysics Data System (ADS)

    Kerbacher, M. E.; Deaton, J. W.; Phinney, L. C.; Mitchell, L. J.; Duggan, J. L.

    2007-10-01

    Positron Emission Tomography is useful in detecting biological abnormalities. The technique involves attaching radiotracers to a material used inside the body, in many cases glucose. Glucose is absorbed most readily in areas of unusual cell growth or uptake of nutrients so through natural processes the treated glucose highlights regions of tumors and other degenerative disorders such as Alzheimer's disease. The higher the concentration of isotopes, the more dynamic the area. Isotopes commonly used as tracers are 11C, 18F, 13N, and 15O due to their easy production and short half-lives. Once the tracers have saturated an area of tissue they are detected using coincidence detectors collinear with individual isotopes. As the isotope decays it emits a positron which, upon annihilating an electron, produces two oppositely directioned gamma rays. The PET machine consists of several pairs of detectors, each 180 degrees from their partner detector. When the oppositely positioned detectors are collinear with the area of the isotope, a computer registers the location of the isotope and can compile an image of the activity of the highlighted area based on the position and strength of the isotopes.

  1. Electron-Positron Flows around Magnetars

    NASA Astrophysics Data System (ADS)

    Beloborodov, Andrei M.

    2013-11-01

    The twisted magnetospheres of magnetars must sustain a persistent flow of electron-positron plasma. The flow dynamics is controlled by the radiation field around the hot neutron star. The problem of plasma motion in the self-consistent radiation field is solved using the method of virtual beams. The plasma and radiation exchange momentum via resonant scattering and self-organize into the "radiatively locked" outflow with a well-defined, decreasing Lorentz factor. There is an extended zone around the magnetar where the plasma flow is ultra-relativistic; its Lorentz factor is self-regulated so that it can marginally scatter thermal photons. The flow becomes slow and opaque in an outer equatorial zone, where the decelerated plasma accumulates and annihilates; this region serves as a reflector for the thermal photons emitted by the neutron star. The e ± flow carries electric current, which is sustained by a moderate induced electric field. The electric field maintains a separation between the electron and positron velocities, against the will of the radiation field. The two-stream instability is then inevitable, and the induced turbulence can generate low-frequency emission. In particular, radio emission may escape around the magnetic dipole axis of the star. Most of the flow energy is converted to hard X-ray emission, which is examined in an accompanying paper.

  2. ELECTRON-POSITRON FLOWS AROUND MAGNETARS

    SciTech Connect

    Beloborodov, Andrei M.

    2013-11-10

    The twisted magnetospheres of magnetars must sustain a persistent flow of electron-positron plasma. The flow dynamics is controlled by the radiation field around the hot neutron star. The problem of plasma motion in the self-consistent radiation field is solved using the method of virtual beams. The plasma and radiation exchange momentum via resonant scattering and self-organize into the 'radiatively locked' outflow with a well-defined, decreasing Lorentz factor. There is an extended zone around the magnetar where the plasma flow is ultra-relativistic; its Lorentz factor is self-regulated so that it can marginally scatter thermal photons. The flow becomes slow and opaque in an outer equatorial zone, where the decelerated plasma accumulates and annihilates; this region serves as a reflector for the thermal photons emitted by the neutron star. The e {sup ±} flow carries electric current, which is sustained by a moderate induced electric field. The electric field maintains a separation between the electron and positron velocities, against the will of the radiation field. The two-stream instability is then inevitable, and the induced turbulence can generate low-frequency emission. In particular, radio emission may escape around the magnetic dipole axis of the star. Most of the flow energy is converted to hard X-ray emission, which is examined in an accompanying paper.

  3. Prize-based Contingency Management for the Treatment of Substance Abusers: A Meta-analysis

    PubMed Central

    Benishek, L. A.; Dugosh, K. L.; Kirby, K. C.; Matejkowski, J.; Clements, N. T.; Seymour, B. L.; Festinger, D. S.

    2014-01-01

    Aim To review randomized controlled trials to assess efficacy of a prize-based contingency management procedure in reducing substance use (where a drug-free breath or urine sample provides a chance of winning a prize). Methods A meta-analysis was conducted on articles published from January 2000 to February 2013 to determine the effect size of studies comparing prize-based contingency management to a treatment-as-usual control condition (k=19 studies). Parallel analyses evaluated the efficacy of both short- (k=9 studies) and long-term outcomes (k=6 studies) of prize-based contingency management . Results The average end-of-treatment effect size (Cohen's d) was .46 [95% CI=0.37,0.54). This effect size decreased at the short-term (≤ 3-month) post-intervention follow-up to .33 (95% CI=0.12,0.54) and at the 6-month follow-up time point there was no detectable effect (d=-.09 (95% CI=−0.28,0.10)). Conclusion Adding prize-based contingency management to behavioral support for substance use disorders can increase short-term abstinence but the effect does not appear to persist to 6 months. PMID:24750232

  4. The 'home advantage' is necessary for a full winner effect and changes in post-encounter testosterone.

    PubMed

    Fuxjager, Matthew J; Mast, Gabriel; Becker, Elizabeth A; Marler, Catherine A

    2009-08-01

    Winning aggressive contests can both enhance future winning ability and change post-encounter hormones; however, it remains unclear if the context of a fight also influences such winner effects and hormone changes. We investigated this issue by using California mice (Peromyscus californicus) to test if the effect of residency status is necessary to improve future winning ability and alter post-encounter hormones. Male mice were subjected to an aggressive contest and their blood was collected 45 min after the fight. Upon contest initiation, focal mice had a 'home advantage' and three prior winning experiences, only one of these factors, or neither factor. Only individuals with a 'home advantage' and prior winning experience showed a full winner effect. Post-encounter changes in testosterone and progesterone resulted from an interaction between residency status and winning experience. These data indicate that in male California mice a 'home advantage' is necessary to produce the full winner effect and that residency status helps regulate inter-individual variation in the expression of post-encounter testosterone pulses and progesterone changes. Furthermore, these respective behavioral and physiological phenomena might be modulated in a context-specific manner, in part by the surrounding physical environment.

  5. A comparison of the randomized play-the-winner rule and the triangular test for clinical trials with binary responses.

    PubMed

    Coad, D S; Rosenberger, W F

    1999-04-15

    We consider a clinical trial model comparing an experimental treatment with a control treatment when the responses are binary. For fixed significance level and power, we compare the expected number of treatment failures for two designs--the randomized play-the-winner rule and the triangular test. The former is an example of an adaptive design while the latter is an example of a fully sequential design. We show how to determine the sample size for the randomized play-the-winner rule and how to choose the stopping boundaries for the triangular test so that the two designs have similar power functions. With this choice of design parameters, simulation indicates that the triangular test is generally more effective at reducing the expected number of treatment failures, particularly when there is a large difference between the two probabilities of success. The expected number of treatment failures can be further reduced if the triangular test is applied using the randomized play-the-winner rule to assign each patient to one of the two treatments.

  6. Development of a Positron Source for JLab at the IAC

    SciTech Connect

    Forest, Tony

    2013-10-12

    We report on the research performed towards the development of a positron sour for Jefferson Lab's (JLab) Continuous Electron Beam Accelerator Facility (CEBAF) in Newport News, VA. The first year of work was used to benchmark the predictions of our current simulation with positron production efficiency measurements at the IAC. The second year used the benchmarked simulation to design a beam line configuration which optimized positron production efficiency while minimizing radioactive waste as well as design and construct a positron converter target. The final year quantified the performance of the positron source. This joint research and development project brought together the experiences of both electron accelerator facilities. Our intention is to use the project as a spring board towards developing a program of accelerator based research and education which will train students to meet the needs of both facilities as well as provide a pool of trained scientists.

  7. Positron beam lifetime spectroscopy at Lawrence Livermore National Laboratory

    SciTech Connect

    Howell, R.H.; Cowan, T.E.; Hartley, J.H.; Stern, P.A. |

    1996-10-01

    Defect analysis is needed for samples ranging in thickness from thin films to large engineering parts. We are meeting that need with two positron beam lifetime spectrometers: on on a 3 MeV electrostatic accelerator and the second on our high current linac beam. The high energy beam spectrometer performs positron lifetime analysis on thick samples which can be encapsulated for containment or for in situ measurements in controlled environments. At our high current beam, we are developing a low energy, microscopically focused, pulsed positron beam to enable positron annihilation lifetime spectroscopy for defect specific, 3-D maps with sub-micron location resolution. The data from these instruments with the aid of first principles calculations of defect specific positron lifetimes.

  8. The multi-scattering model for calculations of positron spatial distribution in the multilayer stacks, useful for conventional positron measurements

    SciTech Connect

    Dryzek, Jerzy; Siemek, Krzysztof

    2013-08-21

    The spatial distribution of positrons emitted from radioactive isotopes into stacks or layered samples is a subject of the presented report. It was found that Monte Carlo (MC) simulations using GEANT4 code are not able to describe correctly the experimental data of the positron fractions in stacks. The mathematical model was proposed for calculations of the implantation profile or positron fractions in separated layers or foils being components of a stack. The model takes into account only two processes, i.e., the positron absorption and backscattering at interfaces. The mathematical formulas were applied in the computer program called LYS-1 (layers profile analysis). The theoretical predictions of the model were in the good agreement with the results of the MC simulations for the semi infinite sample. The experimental verifications of the model were performed on the symmetrical and non-symmetrical stacks of different foils. The good agreement between the experimental and calculated fractions of positrons in components of a stack was achieved. Also the experimental implantation profile obtained using the depth scanning of positron implantation technique is very well described by the theoretical profile obtained within the proposed model. The LYS-1 program allows us also to calculate the fraction of positrons which annihilate in the source, which can be useful in the positron spectroscopy.

  9. Population cycles and species diversity in dynamic Kill-the-Winner model of microbial ecosystems

    NASA Astrophysics Data System (ADS)

    Maslov, Sergei; Sneppen, Kim

    2017-01-01

    Determinants of species diversity in microbial ecosystems remain poorly understood. Bacteriophages are believed to increase the diversity by the virtue of Kill-the-Winner infection bias preventing the fastest growing organism from taking over the community. Phage-bacterial ecosystems are traditionally described in terms of the static equilibrium state of Lotka-Volterra equations in which bacterial growth is exactly balanced by losses due to phage predation. Here we consider a more dynamic scenario in which phage infections give rise to abrupt and severe collapses of bacterial populations whenever they become sufficiently large. As a consequence, each bacterial population in our model follows cyclic dynamics of exponential growth interrupted by sudden declines. The total population of all species fluctuates around the carrying capacity of the environment, making these cycles cryptic. While a subset of the slowest growing species in our model is always driven towards extinction, in general the overall ecosystem diversity remains high. The number of surviving species is inversely proportional to the variation in their growth rates but increases with the frequency and severity of phage-induced collapses. Thus counter-intuitively we predict that microbial communities exposed to more violent perturbations should have higher diversity.

  10. Versatile networks of simulated spiking neurons displaying winner-take-all behavior

    PubMed Central

    Chen, Yanqing; McKinstry, Jeffrey L.; Edelman, Gerald M.

    2013-01-01

    We describe simulations of large-scale networks of excitatory and inhibitory spiking neurons that can generate dynamically stable winner-take-all (WTA) behavior. The network connectivity is a variant of center-surround architecture that we call center-annular-surround (CAS). In this architecture each neuron is excited by nearby neighbors and inhibited by more distant neighbors in an annular-surround region. The neural units of these networks simulate conductance-based spiking neurons that interact via mechanisms susceptible to both short-term synaptic plasticity and STDP. We show that such CAS networks display robust WTA behavior unlike the center-surround networks and other control architectures that we have studied. We find that a large-scale network of spiking neurons with separate populations of excitatory and inhibitory neurons can give rise to smooth maps of sensory input. In addition, we show that a humanoid brain-based-device (BBD) under the control of a spiking WTA neural network can learn to reach to target positions in its visual field, thus demonstrating the acquisition of sensorimotor coordination. PMID:23515493

  11. Population cycles and species diversity in dynamic Kill-the-Winner model of microbial ecosystems.

    PubMed

    Maslov, Sergei; Sneppen, Kim

    2017-01-04

    Determinants of species diversity in microbial ecosystems remain poorly understood. Bacteriophages are believed to increase the diversity by the virtue of Kill-the-Winner infection bias preventing the fastest growing organism from taking over the community. Phage-bacterial ecosystems are traditionally described in terms of the static equilibrium state of Lotka-Volterra equations in which bacterial growth is exactly balanced by losses due to phage predation. Here we consider a more dynamic scenario in which phage infections give rise to abrupt and severe collapses of bacterial populations whenever they become sufficiently large. As a consequence, each bacterial population in our model follows cyclic dynamics of exponential growth interrupted by sudden declines. The total population of all species fluctuates around the carrying capacity of the environment, making these cycles cryptic. While a subset of the slowest growing species in our model is always driven towards extinction, in general the overall ecosystem diversity remains high. The number of surviving species is inversely proportional to the variation in their growth rates but increases with the frequency and severity of phage-induced collapses. Thus counter-intuitively we predict that microbial communities exposed to more violent perturbations should have higher diversity.

  12. STDP Installs in Winner-Take-All Circuits an Online Approximation to Hidden Markov Model Learning

    PubMed Central

    Kappel, David; Nessler, Bernhard; Maass, Wolfgang

    2014-01-01

    In order to cross a street without being run over, we need to be able to extract very fast hidden causes of dynamically changing multi-modal sensory stimuli, and to predict their future evolution. We show here that a generic cortical microcircuit motif, pyramidal cells with lateral excitation and inhibition, provides the basis for this difficult but all-important information processing capability. This capability emerges in the presence of noise automatically through effects of STDP on connections between pyramidal cells in Winner-Take-All circuits with lateral excitation. In fact, one can show that these motifs endow cortical microcircuits with functional properties of a hidden Markov model, a generic model for solving such tasks through probabilistic inference. Whereas in engineering applications this model is adapted to specific tasks through offline learning, we show here that a major portion of the functionality of hidden Markov models arises already from online applications of STDP, without any supervision or rewards. We demonstrate the emergent computing capabilities of the model through several computer simulations. The full power of hidden Markov model learning can be attained through reward-gated STDP. This is due to the fact that these mechanisms enable a rejection sampling approximation to theoretically optimal learning. We investigate the possible performance gain that can be achieved with this more accurate learning method for an artificial grammar task. PMID:24675787

  13. Population cycles and species diversity in dynamic Kill-the-Winner model of microbial ecosystems

    PubMed Central

    Maslov, Sergei; Sneppen, Kim

    2017-01-01

    Determinants of species diversity in microbial ecosystems remain poorly understood. Bacteriophages are believed to increase the diversity by the virtue of Kill-the-Winner infection bias preventing the fastest growing organism from taking over the community. Phage-bacterial ecosystems are traditionally described in terms of the static equilibrium state of Lotka-Volterra equations in which bacterial growth is exactly balanced by losses due to phage predation. Here we consider a more dynamic scenario in which phage infections give rise to abrupt and severe collapses of bacterial populations whenever they become sufficiently large. As a consequence, each bacterial population in our model follows cyclic dynamics of exponential growth interrupted by sudden declines. The total population of all species fluctuates around the carrying capacity of the environment, making these cycles cryptic. While a subset of the slowest growing species in our model is always driven towards extinction, in general the overall ecosystem diversity remains high. The number of surviving species is inversely proportional to the variation in their growth rates but increases with the frequency and severity of phage-induced collapses. Thus counter-intuitively we predict that microbial communities exposed to more violent perturbations should have higher diversity. PMID:28051127

  14. Learning and stabilization of winner-take-all dynamics through interacting excitatory and inhibitory plasticity

    PubMed Central

    Binas, Jonathan; Rutishauser, Ueli; Indiveri, Giacomo; Pfeiffer, Michael

    2014-01-01

    Winner-Take-All (WTA) networks are recurrently connected populations of excitatory and inhibitory neurons that represent promising candidate microcircuits for implementing cortical computation. WTAs can perform powerful computations, ranging from signal-restoration to state-dependent processing. However, such networks require fine-tuned connectivity parameters to keep the network dynamics within stable operating regimes. In this article, we show how such stability can emerge autonomously through an interaction of biologically plausible plasticity mechanisms that operate simultaneously on all excitatory and inhibitory synapses of the network. A weight-dependent plasticity rule is derived from the triplet spike-timing dependent plasticity model, and its stabilization properties in the mean-field case are analyzed using contraction theory. Our main result provides simple constraints on the plasticity rule parameters, rather than on the weights themselves, which guarantee stable WTA behavior. The plastic network we present is able to adapt to changing input conditions, and to dynamically adjust its gain, therefore exhibiting self-stabilization mechanisms that are crucial for maintaining stable operation in large networks of interconnected subunits. We show how distributed neural assemblies can adjust their parameters for stable WTA function autonomously while respecting anatomical constraints on neural wiring. PMID:25071538

  15. Activity Report: "Escola de Cultura de Pau", the Laureate of the First Evens Prize for Peace Education

    ERIC Educational Resources Information Center

    Delvou, Marjolein

    2011-01-01

    On March 18th 2011 an independent jury of experts convened in Antwerp, Belgium, to select the laureate of the first Evens Prize for Peace Education from a shortlist of eleven organizations from all over Europe. After a long day of intense discussions, the jury agreed unanimously to award the prize to the "Escola de Cultura de Pau"…

  16. Randomized Trial Comparing Two Treatment Strategies Using Prize-Based Reinforcement of Abstinence in Cocaine and Opiate Users

    ERIC Educational Resources Information Center

    Preston, Kenzie L.; Ghitza, Udi E.; Schmittner, John P.; Schroeder, Jennifer R.; Epstein, David H.

    2008-01-01

    We compared two strategies of prize-based contingency management (CM) in methadone-maintained outpatients. Urine was tested thrice weekly for 5 weeks pre-CM, 12 weeks CM, and 8 weeks post-CM. Participants were randomly assigned to a cocaine contingency (four prize draws for each cocaine-negative urine, N = 29) or an opiate-cocaine contingency (one…

  17. Roles of superthermal electrons and positrons on positron-acoustic solitary waves and double layers in electron-positron-ion plasmas.

    PubMed

    Alam, M S; Uddin, M J; Masud, M M; Mamun, A A

    2014-09-01

    Positron-acoustic (PA) solitary waves (SWs) and double layers (DLs) in four-component plasmas consisting of immobile positive ions, mobile cold positrons, and superthermal (kappa distributed) hot positrons and electrons are investigated both numerically and analytically by deriving Korteweg-de Vries (K-dV), modified K-dV (mK-dV), and Gardner equations along with their DLs solutions using the reductive perturbation method. It is examined that depending on the plasma parameters, the K-dV SWs, Gardner SWs, and DLs support either compressive or rarefactive structures, whereas mK-dV SWs support only compressive structure. It is also found that the presence of superthermal (kappa distributed) hot positrons and hot electrons significantly modify the basic features of PA SWs as well as PA DLs. Besides, the critical number density ratio of hot positrons and cold positrons play an important role in the polarity of PA SWs and DLs. The implications of our results in different space as well as laboratory plasma environments are briefly discussed.

  18. The impact of positrons beam on the propagation of super freak waves in electron-positron-ion plasmas

    NASA Astrophysics Data System (ADS)

    Ali Shan, S.; El-Tantawy, S. A.

    2016-07-01

    In this work, we examine the nonlinear propagation of planar ion-acoustic freak waves in an unmagnetized plasma consisting of cold positive ions and superthermal electrons subjected to cold positrons beam. For this purpose, the reductive perturbation method is used to derive a nonlinear Schrödinger equation (NLSE) for the evolution of electrostatic potential wave. We determine the domain of the plasma parameters where the rogue waves exist. The effect of the positron beam on the modulational instability of the ion-acoustic rogue waves is discussed. It is found that the region of the modulational stability is enhanced with the increase of positron beam speed and positron population. Second as positrons beam increases the nonlinearities of the plasma system, large amplitude ion acoustic rogue waves are pointed out. The present results will be helpful in providing a good fit between the theoretical analysis and real applications in future laboratory plasma experiments.

  19. Bonner Prize: The Elastic Form Factors of the Nucleon

    NASA Astrophysics Data System (ADS)

    Perdrisat, Charles F.

    2017-01-01

    A series of experiments initiated in 1998 at the then new Continuous Electron Beam Accelerator, or CEBAF in Newport News Virginia, resulted in unexpected results, changing significantly our understanding of the structure of the proton. These experiments used a relatively new technique to obtain the ratio of the two form factors of the proton, namely polarization. An intense beam of highly polarized electrons with energy up to 6 GeV was made to interact elastically with un-polarized protons in a hydrogen target. The polarization of the recoiling protons, with energies up to 5 GeV, was measured from a second interaction in a polarimeter consisting of blocs of graphite or CH2 and tracking wire chambers. The scattered electrons were detected in an electromagnetic lead-glass calorimeter, to select elastically scattered events. After a short introduction describing the path which brought me from the University of Geneva to the College of William and Mary in 1966, I will introduce the subject of elastic electron scattering, describe some of the apparatus required for such experiments, and show the results which were unexpected at the time. These results demonstrated unequivocally that the two form factors required to describe elastic ep scattering, electric GE and magnetic GM in the Born approximation, had a drastically different dependence upon the four-momentum squared q2 = q2 -ω2 with q the momentum, and ω the energy transferred in the reaction. The finding, in flagrant disagreement with the data available at the time, which had been obtained dominantly from cross section measurements of the type first used by Nobel Prize R. Hofstadter 60 years ago, have led to a reexamination of the information provided by form factors on the structure of the nucleon, in particular its quark-gluon content. The conclusion will then be a brief outline of several theoretical considerations to put the results in a proper perspective.

  20. Small Prizes Improve Food Selection in a School Cafeteria Without Increasing Waste.

    PubMed

    Hudgens, Michelle E; Barnes, Allison S; Lockhart, Mary Kate; Ellsworth, Samantha C; Beckford, Monna; Siegel, Robert M

    2017-02-01

    We recently demonstrated that small prizes given for a "Power Plate" (plain fat-free milk, entrée, fruit and vegetable) can be used in an elementary school cafeteria to increase healthful food selection by over 300%. The purpose of this study was to measure changes in food waste when the Power Plate (PP) program is implemented. The PP intervention was conducted at an inner-city elementary school. Emoticons were placed next to the preferred foods and children were given a small prize if they selected the PP. Data were obtained by observation and cash register receipts. The trays of 111 students before the intervention and 96 after were examined for content and waste. PP selection increased from 2% to 73% ( P < .001). There was no significant change in waste. We conclude that small prizes as an incentive for better food selection does not lead to an increase food waste.

  1. Applicability of modified effective-range theory to positron-atom and positron-molecule scattering

    SciTech Connect

    Idziaszek, Zbigniew; Karwasz, Grzegorz

    2006-06-15

    We analyze low-energy scattering of positrons on Ar atoms and N{sub 2} molecules using the modified effective-range theory (MERT) developed by O'Malley, et al. [J. Math. Phys. 2, 491 (1961)]. We use the formulation of MERT based on exact solutions of the Schroedinger equation with polarization potential rather than low-energy expansions of phase shifts into momentum series. We show that MERT describes the experimental data well, provided that effective-range expansion is performed both for s- and p-wave scattering, which dominate in the considered regime of positron energies (0.4-2 eV). We estimate the values of the s-wave scattering length and the effective range for e{sup +}-Ar and e{sup +}-N{sub 2} collisions.

  2. Stress Testing of the Philips 60W Replacement Lamp L Prize Entry

    SciTech Connect

    Poplawski, Michael E.; Ledbetter, Marc R.; Smith, Mark

    2012-04-24

    The Pacific Northwest National Laboratory, operated by Battelle for the U.S. Department of Energy, worked with Intertek to develop a procedure for stress testing medium screw-base light sources. This procedure, composed of alternating stress cycles and performance evaluation, was used to qualitatively compare and contrast the durability and reliability of the Philips 60W replacement lamp L Prize entry with market-proven compact fluorescent lamps (CFLs) with comparable light output and functionality. The stress cycles applied simultaneous combinations of electrical, thermal, vibration, and humidity stresses of increasing magnitude. Performance evaluations measured relative illuminance, x chromaticity and y chromaticity shifts after each stress cycle. The Philips L Prize entry lamps appear to be appreciably more durable than the incumbent energy-efficient technology, as represented by the evaluated CFLs, and with respect to the applied stresses. Through the course of testing, all 15 CFL samples permanently ceased to function as a result of the applied stresses, while only 1 Philips L Prize entry lamp exhibited a failure, the nature of which was minor, non-destructive, and a consequence of a known (and resolved) subcontractor issue. Given that current CFL technology appears to be moderately mature and no Philips L Prize entry failures could be produced within the stress envelope causing 100 percent failure of the benchmark CFLs, it seems that, in this particular implementation, light-emitting diode (LED) technology would be much more durable in the field than current CFL technology. However, the Philips L Prize entry lamps used for testing were carefully designed and built for the competition, while the benchmark CFLs were mass produced for retail sale—a distinction that should be taken into consideration. Further reliability testing on final production samples would be necessary to judge the extent to which the results of this analysis apply to production versions

  3. The 2014 Nobel Prize in Physiology or Medicine: a spatial model for cognitive neuroscience.

    PubMed

    Burgess, Neil

    2014-12-17

    Understanding how the cognitive functions of the brain arise from its basic physiological components has been an enticing final frontier in science for thousands of years. The Nobel Prize in Physiology or Medicine 2014 was awarded one half to John O'Keefe, the other half jointly to May-Britt Moser and Edvard I. Moser "for their discoveries of cells that constitute a positioning system in the brain." This prize recognizes both a paradigm shift in the study of cognitive neuroscience, and some of the amazing insights that have followed from it concerning how the world is represented within the brain.

  4. Mega-prizes in medicine: big cash awards may stimulate useful and rapid therapeutic innovation.

    PubMed

    Charlton, Bruce G

    2007-01-01

    Following Horrobin's suggestion of 1986, I argue that offering very large prizes (tens of millions of US dollars, or more) for solving specific therapeutic problems, would be an excellent strategy for promoting the rapid development of effective new treatments. The two mainstream ways of paying for medical research are funding the process with grants or funding the outcome via patent protection. When grants are used to fund the process of research the result tends to be 'pure' science, guided by intrinsic scientific objectives. Practical results, such as useful therapeutic advances, are a by-product. Patent-seeking research, by contrast, is more focused on technology than science. It seeks practical results; and aims to pay for itself (and make a profit) in the long term by generating a patentable product or procedure. Prize-seeking research is subject to different incentives and applicable to different situations than either process-funded or patent-seeking research. Prize seeking researchers have a strong incentive to solve the specified problem as rapidly as possible, but the problem may be solved using old ideas that are scientifically mundane or unpatentable technologies and methods. Prizes therefore seem to generate solutions which are incremental extensions, new applications or novel combinations of already-existing technologies. The main use of mega-prizes in medicine would be to accelerate therapeutic progress in stagnant fields of research and to address urgent problems. For example, medical charities focused on specific diseases should consider accumulating their resources until they can offer a mega-prize for solving a clinical problem of special concern to their patients. Prize money should be big enough to pay for the research and development, the evaluation of the new treatment in a clinical trial, and with a large profit left-over to compensate for the intrinsic risk of competing. Sufficiently large amounts of money, and the prestige and publicity

  5. The 2014 Nobel Prize in Physiology or Medicine: A Spatial Model for Cognitive Neuroscience

    PubMed Central

    Burgess, Neil

    2014-01-01

    Understanding how the cognitive functions of the brain arise from its basic physiological components has been an enticing final frontier in science for thousands of years. The Nobel Prize in Physiology or Medicine 2014 was awarded one half to John O’Keefe, the other half jointly to May-Britt Moser and Edvard I. Moser “for their discoveries of cells that constitute a positioning system in the brain.” This prize recognizes both a paradigm shift in the study of cognitive neuroscience, and some of the amazing insights that have followed from it concerning how the world is represented within the brain. PMID:25521374

  6. Positron Emission Tomography of the Heart

    DOE R&D Accomplishments Database

    Schelbert, H. R.; Phelps, M. E.; Kuhl, D. E.

    1979-01-01

    Positron emission computed tomography (PCT) represents an important new tool for the noninvasive evaluation and, more importantly, quantification of myocardial performance. Most currently available techniques permit assessment of only one aspect of cardiac function, i.e., myocardial perfusion by gamma scintillation camera imaging with Thallium-201 or left ventricular function by echocardiography or radionuclide angiocardiography. With PCT it may become possible to study all three major segments of myocardial performance, i.e., regional blood flow, mechanical function and, most importantly, myocardial metabolism. Each of these segments can either be evaluated separately or in combination. This report briefly describes the principles and technological advantages of the imaging device, reviews currently available radioactive tracers and how they can be employed for the assessment of flow, function and metabolism; and, lastly, discusses possible applications of PCT for the study of cardiac physiology or its potential role in the diagnosis of cardiac disease.

  7. Compact conscious animal positron emission tomography scanner

    DOEpatents

    Schyler, David J.; O'Connor, Paul; Woody, Craig; Junnarkar, Sachin Shrirang; Radeka, Veljko; Vaska, Paul; Pratte, Jean-Francois; Volkow, Nora

    2006-10-24

    A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal for an event, generating an address signal representing a detecting channel, generating a detector channel signal including the time and address signals, and generating a composite signal including the channel signal and similarly generated signals. The composite signal includes events from detectors in a block and is serially output. An apparatus that serially transfers annihilation information from a block includes time signal generators for detectors in a block and an address and channel signal generator. The PET scanner includes a ring tomograph that mounts onto a portion of an animal, which includes opposing block pairs. Each of the blocks in a block pair includes a scintillator layer, detection array, front-end array, and a serial encoder. The serial encoder includes time signal generators and an address signal and channel signal generator.

  8. Tumor Quantification in Clinical Positron Emission Tomography

    PubMed Central

    Bai, Bing; Bading, James; Conti, Peter S

    2013-01-01

    Positron emission tomography (PET) is used extensively in clinical oncology for tumor detection, staging and therapy response assessment. Quantitative measurements of tumor uptake, usually in the form of standardized uptake values (SUVs), have enhanced or replaced qualitative interpretation. In this paper we review the current status of tumor quantification methods and their applications to clinical oncology. Factors that impede quantitative assessment and limit its accuracy and reproducibility are summarized, with special emphasis on SUV analysis. We describe current efforts to improve the accuracy of tumor uptake measurements, characterize overall metabolic tumor burden and heterogeneity of tumor uptake, and account for the effects of image noise. We also summarize recent developments in PET instrumentation and image reconstruction and their impact on tumor quantification. Finally, we offer our assessment of the current development needs in PET tumor quantification, including practical techniques for fully quantitative, pharmacokinetic measurements. PMID:24312151

  9. Positron Emission Tomography with improved spatial resolution

    SciTech Connect

    Drukier, A.K.

    1990-04-01

    Applied Research Corporation (ARC) proposed the development of a new class of solid state detectors called Superconducting Granular Detectors (SGD). These new detectors permit considerable improvements in medical imaging, e.g. Positron Emission Tomography (PET). The biggest impact of this technique will be in imaging of the brain. It should permit better clinical diagnosis of such important diseases as Altzheimer's or schizophrenia. More specifically, we will develop an improved PET-imager; a spatial resolution 2 mm may be achievable with SGD. A time-of-flight capability(t {approx} 100 psec) will permit better contrast and facilitate 3D imaging. In the following, we describe the results of the first 9 months of the development.

  10. Instrumentation optimization for positron emission mammography

    SciTech Connect

    Moses, William W.; Qi, Jinyi

    2003-06-05

    The past several years have seen designs for PET cameras optimized to image the breast, commonly known as Positron Emission Mammography or PEM cameras. The guiding principal behind PEM instrumentation is that a camera whose field of view is restricted to a single breast has higher performance and lower cost than a conventional PET camera. The most common geometry is a pair of parallel planes of detector modules, although geometries that encircle the breast have also been proposed. The ability of the detector modules to measure the depth of interaction (DOI) is also a relevant feature. This paper finds that while both the additional solid angle coverage afforded by encircling the breast and the decreased blurring afforded by the DOI measurement improve performance, the ability to measure DOI is more important than the ability to encircle the breast.

  11. The source and distribution of Galactic positrons

    NASA Technical Reports Server (NTRS)

    Purcell, W. R.; Dixon, D. D.; Cheng, L.-X.; Leventhal, M.; Kinzer, R. L.; Kurfess, J. D.; Skibo, J. G.; Smith, D. M.; Tueller, J.

    1997-01-01

    The oriented scintillation spectrometer experiment (OSSE) observations of the Galactic plane and the Galactic center region were combined with observations acquired with other instruments in order to produce a map of the Galactic 511 keV annihilation radiation. Two mapping techniques were applied to the data: the maximum entropy method, and the basis pursuit inversion method. The resulting maps are qualitatively similar and show evidence for a central bulge and a weak galactic disk component. The weak disk is consistent with that expected from positrons produced by the decay of radioactive Al-26 in the interstellar medium. Both maps suggest an enhanced region of emission near l = -4 deg, b = 7 deg, with a flux of approximately 50 percent of that of the bulge. The existence of this emission appears significant, although the location is not well determined. The source of this enhanced emission is presently unknown.

  12. Positrons and Antiprotons in Galactic Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Cowsik, R.

    2016-10-01

    I consider the impact of recent measurements of positron and antiproton spectra in cosmic rays on our understanding of the origins and propagation of cosmic rays, as well as on the annihilation and decay characteristics of particles of Galactic dark matter, from the perspective of current models postulating energy-dependent leakage of cosmic rays from the Galaxy and of the nested leaky-box model, in which the leakage from the Galaxy is independent of energy. The nested leaky-box model provides a straightforward and consistent explanation of the observed spectral intensities, and finds no compelling need for a contribution from the annihilation or decay of Galactic dark matter. Improved observations and modeling efforts are needed to probe the properties of dark matter deeply enough to be significant to particle physics and cosmology.

  13. Making Relativistic Positrons Using Ultra-Intense Short Pulse Lasers

    SciTech Connect

    Chen, H; Wilks, S; Bonlie, J; Chen, C; Chen, S; Cone, K; Elberson, L; Gregori, G; Liang, E; Price, D; Van Maren, R; Meyerhofer, D D; Mithen, J; Murphy, C V; Myatt, J; Schneider, M; Shepherd, R; Stafford, D; Tommasini, R; Beiersdorfer, P

    2009-08-24

    This paper describes a new positron source produced using ultra-intense short pulse lasers. Although it has been studied in theory since as early as the 1970s, the use of lasers as a valuable new positron source was not demonstrated experimentally until recent years, when the petawatt-class short pulse lasers were developed. In 2008 and 2009, in a series of experiments performed at Lawrence Livermore National Laboratory, a large number of positrons were observed after shooting a millimeter thick solid gold target. Up to 2 x 10{sup 10} positrons per steradian ejected out the back of {approx}mm thick gold targets were detected. The targets were illuminated with short ({approx}1 ps) ultra-intense ({approx}1 x 10{sup 20} W/cm{sup 2}) laser pulses. These positrons are produced predominantly by the Bethe-Heitler process, and have an effective temperature of 2-4 MeV, with the distribution peaking at 4-7 MeV. The angular distribution of the positrons is anisotropic. For a wide range of applications, this new laser based positron source with its unique characteristics may complements the existing sources using radioactive isotopes and accelerators.

  14. The Calibration of the PEPPo Polarimeter for Electrons and Positrons

    SciTech Connect

    Adeyemi, Adeleke Hakeem; Voutier, Eric J-.M.

    2013-06-01

    The PEPPo (Polarized Electrons for Polarized Positrons) experiment at Jefferson Laboratory investigated the polarization transfer from longitudinally polarized electrons to longitudinally polarized positrons, with the aim of developing this technology for a low energy (~MeV) polarized positron source. Polarization of the positrons was measured by means of a Compton transmission polarimeter where incoming positrons transfer their polarization into circularly polarized photons that were subsequently analyzed by a thick polarized iron target. The measurement of the transmitted photon flux with respect to the orientation of the target polarization (+-) or the helicity (+-) of the incoming leptons provided the measurement of their polarization. Similar measurements with a known electron beam were also performed for calibration purposes. This presentation will describe the apparatus and calibrations performed at the injector at the Jefferson Laboratory to measure positron polarization in the momentum range 3.2-6.2 MeV/c, specifically to quantify the positron analyzing power from electron experimental data measured over a comparable momentum range.

  15. Positron scattering measurements for application to medical physics

    NASA Astrophysics Data System (ADS)

    Sullivan, James

    2015-09-01

    While the use of positrons in medical imaging is now well established, there is still much to learn regarding the transport of positrons through the body, and the subsequent damage induced. Current models of dosimetry use only a crude approximation of the collision physics involved, and at low energies misrepresent the thermalisation process to a considerable degree. Recently, collaborative work has commenced to attempt to refine these models, incorporating a better representation of the underlying physics and trying to gain a better understanding of the damage done after the emission of a positron from a medical radioisotope. This problem is being attacked from several different angles, with new models being developed based upon established techniques in plasma and swarm physics. For all these models, a realistic representation of the collision processes of positrons with relevant molecular species is required. At the Australian National University, we have undertaken a program of measurements of positron scattering from a range of molecules that are important in biological systems, with a focus on analogs to DNA. This talk will present measurements of positron scattering from a range of these molecules, as well as describing the experimental techniques employed to make such measurements. Targets have been measured that are both liquid and solid at room temperature, and new approaches have been developed to get absolute cross section data. The application of the data to various models of positron thermalisation will also be described.

  16. Making relativistic positrons using ultraintense short pulse lasers

    SciTech Connect

    Chen Hui; Wilks, S. C.; Bonlie, J. D.; Chen, S. N.; Cone, K. V.; Elberson, L. N.; Price, D. F.; Schneider, M. B.; Shepherd, R.; Stafford, D. C.; Tommasini, R.; Van Maren, R.; Beiersdorfer, P.; Gregori, G.; Meyerhofer, D. D.; Myatt, J.

    2009-12-15

    This paper describes a new positron source using ultraintense short pulse lasers. Although it has been theoretically studied since the 1970s, the use of lasers as a valuable new positron source was not demonstrated experimentally until recent years, when the petawatt-class short pulse lasers were developed. In 2008 and 2009, in a series of experiments performed at the Lawrence Livermore National Laboratory, a large number of positrons were observed after shooting a millimeter thick solid gold target. Up to 2x10{sup 10} positrons/s ejected at the back of approximately millimeter thick gold targets were detected. The targets were illuminated with short (approx1 ps) ultraintense (approx1x10{sup 20} W/cm{sup 2}) laser pulses. These positrons are produced predominantly by the Bethe-Heitler process and have an effective temperature of 2-4 MeV, with the distribution peaking at 4-7 MeV. The angular distribution of the positrons is anisotropic. For a wide range of applications, this new laser-based positron source with its unique characteristics may complement the existing sources based on radioactive isotopes and accelerators.

  17. Data for modeling of positron collisions and transport in gases

    NASA Astrophysics Data System (ADS)

    Petrović, Z. Lj.; Banković, A.; Dujko, S.; Marjanović, S.; Malović, G.; Sullivan, J. P.; Buckman, S. J.

    2013-07-01

    We review the current status of positron cross sections for collisions with atoms and molecules from the viewpoint of their use in studies of positron transport processes in gases, liquids and human tissue. The data include cross sections for positron scattering in rare gases, molecular gases (eg., for N2, H2, CO2, CF4) and in particular for organic molecules and those relevant for applications in medicine (e.g. formic acid and water vapor). The cross sections were taken from an assessment of previously published positron-target cross sections. All of the cross sections are based on binary collision measurements and theoretical calculations, and they were not explicitly modified according to the standard swarm analysis. The main reason for this is systematic lack of experimental data for positron transport properties in gases. However, we believe that our compiled sets of cross sections are at level of sophistication, and of sufficient accuracy, to provide correct interpretation of future positron-based experiments. Using these cross sections as an input in our Monte Carlo simulations and Boltzmann equation treatment, we review some interesting points observed in the profiles of various transport coefficients for positrons in gases. Particular emphasis is placed upon the analysis of kinetic phenomena generated by the explicit influence of Ps formation.

  18. A combined matrix isolation spectroscopy and cryosolid positron moderation apparatus

    SciTech Connect

    Molek, Christopher D.; Michael Lindsay, C.; Fajardo, Mario E.

    2013-03-15

    We describe the design, construction, and operation of a novel apparatus for investigating efficiency improvements in thin-film cryogenic solid positron moderators. We report results from solid neon, argon, krypton, and xenon positron moderators which illustrate the capabilities and limitations of our apparatus. We integrate a matrix isolation spectroscopy diagnostic within a reflection-geometry positron moderation system. We report the optical thickness, impurity content, and impurity trapping site structures within our moderators determined from infrared absorption spectra. We use a retarding potential analyzer to modulate the flow of slow positrons, and report positron currents vs. retarding potential for the different moderators. We identify vacuum ultraviolet emissions from irradiated Ne moderators as the source of spurious signals in our channel electron multiplier slow positron detection channel. Our design is also unusual in that it employs a sealed radioactive Na-22 positron source which can be translated relative to, and isolated from, the cryogenic moderator deposition substrate. This allows us to separate the influences on moderator efficiency of surface contamination by residual gases from those of accumulated radiation damage.

  19. Scattering of positrons and electrons by alkali atoms

    NASA Technical Reports Server (NTRS)

    Stein, T. S.; Kauppila, W. E.; Kwan, C. K.; Lukaszew, R. A.; Parikh, S. P.; Wan, Y. J.; Zhou, S.; Dababneh, M. S.

    1990-01-01

    Absolute total scattering cross sections (Q sub T's) were measured for positrons and electrons colliding with sodium, potassium, and rubidium in the 1 to 102 eV range, using the same apparatus and experimental approach (a beam transmission technique) for both projectiles. The present results for positron-sodium and -rubidium collisions represent the first Q sub T measurements reported for these collision systems. Features which distinguish the present comparisons between positron- and electron-alkali atom Q sub T's from those for other atoms and molecules (room-temperature gases) which have been used as targets for positrons and electrons are the proximity of the corresponding positron- and electron-alkali atom Q sub T's over the entire energy range of overlap, with an indication of a merging or near-merging of the corresponding positron and electron Q sub T's near (and above) the relatively low energy of about 40 eV, and a general tendency for the positron-alkali atom Q sub T's to be higher than the corresponding electron values as the projectile energy is decreased below about 40 eV.

  20. Applications and advances of positron beam spectroscopy: appendix a

    SciTech Connect

    Howell, R. H., LLNL

    1997-11-05

    Over 50 scientists from DOE-DP, DOE-ER, the national laboratories, academia and industry attended a workshop held on November 5-7, 1997 at Lawrence Livermore National Laboratory jointly sponsored by the DOE-Division of Materials Science, The Materials Research Institute at LLNL and the University of California Presidents Office. Workshop participants were charged to address two questions: Is there a need for a national center for materials analysis using positron techniques and can the capabilities at Lawrence Livermore National Laboratory serve this need. To demonstrate the need for a national center the workshop participants discussed the technical advantages enabled by high positron currents and advanced measurement techniques, the role that these techniques will play in materials analysis and the demand for the data. There were general discussions lead by review talks on positron analysis techniques, and their applications to problems in semiconductors, polymers and composites, metals and engineering materials, surface analysis and advanced techniques. These were followed by focus sessions on positron analysis opportunities in these same areas. Livermore now leads the world in materials analysis capabilities by positrons due to developments in response to demands of science based stockpile stewardship. There was a detailed discussion of the LLNL capabilities and a tour of the facilities. The Livermore facilities now include the worlds highest current beam of keV positrons, a scanning pulsed positron microprobe under development capable of three dimensional maps of defect size and concentration, an MeV positron beam for defect analysis of large samples, and electron momentum spectroscopy by positrons. This document is a supplement to the written summary report. It contains a complete schedule, list of attendees and the vuegraphs for the presentations in the review and focus sessions.