The spin-structure functions g1 and g2, and the spin-dependent partial cross-section σTT have been extracted from the polarized cross-sections differences, Δσ∥(ν,Q2) and Δσ⊥(ν,Q2) measured for the ...He3→(e→,e′)X reaction, in the E97-110 experiment at Jefferson Lab. Polarized electrons with energies from 1.147 to 4.404 GeV were scattered at angles of 6∘ and 9∘ from a longitudinally or transversely polarized 3He target. The data cover the kinematic regions of the quasi-elastic, resonance production and beyond. From the extracted spin-structure functions, the first moments Γ1‾(Q2), Γ2(Q2) and ITT(Q2) are evaluated with high precision for the neutron in the Q2 range from 0.035 to 0.24GeV2. The comparison of the data and the chiral effective field theory predictions reveals the importance of proper treatment of the Δ degree of freedom for spin observables.
The New Horizons Spacecraft Fountain, Glen H.; Kusnierkiewicz, David Y.; Hersman, Christopher B. ...
Space science reviews,
10/2008, Letnik:
140, Številka:
1-4
Journal Article
Recenzirano
Odprti dostop
The New Horizons spacecraft was launched on 19 January 2006. The spacecraft was designed to provide a platform for seven instruments designated by the science team to collect and return data from ...Pluto in 2015. The design meets the requirements established by the National Aeronautics and Space Administration (NASA) Announcement of Opportunity AO-OSS-01. The design drew on heritage from previous missions developed at The Johns Hopkins University Applied Physics Laboratory (APL) and other missions such as Ulysses. The trajectory design imposed constraints on mass and structural strength to meet the high launch acceleration consistent with meeting the AO requirement of returning data prior to the year 2020. The spacecraft subsystems were designed to meet tight resource allocations (mass and power) yet provide the necessary control and data handling finesse to support data collection and return when the one-way light time during the Pluto fly-by is 4.5 hours. Missions to the outer regions of the solar system (where the solar irradiance is 1/1000 of the level near the Earth) require a radioisotope thermoelectric generator (RTG) to supply electrical power. One RTG was available for use by New Horizons. To accommodate this constraint, the spacecraft electronics were designed to operate on approximately 200 W. The travel time to Pluto put additional demands on system reliability. Only after a flight time of approximately 10 years would the desired data be collected and returned to Earth. This represents the longest flight duration prior to the return of primary science data for any mission by NASA. The spacecraft system architecture provides sufficient redundancy to meet this requirement with a probability of mission success of greater than 0.85. The spacecraft is now on its way to Pluto, with an arrival date of 14 July 2015. Initial in-flight tests have verified that the spacecraft will meet the design requirements.
Pluto is the only planet in our solar system that has not yet been visited by a spacecraft from Earth. Beyond the orbit of Pluto lies the Kuiper-Belt: home to many primordial objects from the ...earliest days of the formation of the solar system, preserved in a cosmic deep freeze. The Johns Hopkins University/Applied Physics Laboratory (JHU/APL) is planning the mission for the Principal Investigator, Dr. S. Alan Stern of Southwest Research Institute. The planned design of the New Horizons spacecraft, along with a discussion of the design drivers, is presented. The design lifetime of the spacecraft would be 15.25 years. Measures taken to ensure the reliable operation of the spacecraft over the life of the planned mission are discussed.
Superconducting nanowire single photon detectors are capable of single-photon detection across a large spectral range with near unity detection efficiency, picosecond timing jitter, and sub-10 mu m ...position resolution, at rates as high as 10(9) counts/s. In an effort to bring this technology into nuclear physics experiments, we fabricate niobium nitride (NbN) nanowire detectors using ion beam assisted sputtering and test their performance in strong magnetic fields. We demonstrate that these devices are capable of detection of 400 nm wavelength photons with saturated internal quantum efficiency at temperatures of 3 K and in magnetic fields of up to 5 T at high count rates and with nearly zero dark counts.
The NASA new horizons mission to the Pluto system and the Kuiper belt launched from Cape Canaveral on January 19, 2006 after a four-year development, and will arrive at Pluto closest-approach on July ...14, 2015 after a 9.5- year cruise from Earth. Powered by a single radioisotope thermoelectric generator (RTG) from the Galileo-Cassini design and launched on the first flight of a Lockheed Martin Atlas V-551 with a Boeing STAR 48B third stage, the project overcame numerous technical and programmatic challenges to take advantage of the best-last opportunity using existing technology to perform the first-ever reconnaissance of the Pluto system in our lifetime. The mission design for the 2006 launch uses a Jupiter gravity assist to achieve the shortest possible flight time. A rich science return from the Jupiter flyby (February 28, 2007) has been achieved. The engineering and programmatic challenges associated with the spacecraft design, RTG procurement, integration of Lockheed Martin and Boeing launch vehicle components, and the launch approval process are discussed. The current status of the spacecraft and mission is presented.
The generalized forward spin polarizabilities gamma(0) and delta(LT) of the neutron have been extracted for the first time in a Q2 range from 0.1 to 0.9 GeV2. Since gamma(0) is sensitive to nucleon ...resonances and delta(LT) is insensitive to the Delta resonance, it is expected that the pair of forward spin polarizabilities should provide benchmark tests of the current understanding of the chiral dynamics of QCD. The new results on delta(LT) show significant disagreement with chiral perturbation theory calculations, while the data for gamma(0) at low Q2 are in good agreement with a next-to-leading-order relativistic baryon chiral perturbation theory calculation. The data show good agreement with the phenomenological MAID model.
The purpose of this study was to determine what trends exist in the identification and description of participants used in data-based studies published in "Adapted Physical Activity Quarterly" and ...the "Journal of Teaching in Physical Education". Data were analyzed using frequency counts for journals and time periods from the 1980s to 2005 with chi-square tests on gender, race, ethnicity, and socioeconomic status. Results indicate, for example, that across the time span both journals published articles reporting males first over females, Xsuperscript 2 (3) = 22.16, p less than 0.001. Trend data also reveal that even today most data-based studies in these journals fail to report race, ethnicity, and socioeconomic status. Findings are discussed with guiding principles for future research. (Contains 3 figures and 11 notes.)
Incorporating PACER into an Inclusive Basketball Unit Cervantes, Carlos M.; Cohen, Rona; Hersman, Bethany L. ...
Journal of physical education, recreation & dance,
09/2007, Letnik:
78, Številka:
7
Journal Article
Recenzirano
Odprti dostop
The purpose of this article is to introduce PACER as an alternative to the traditional, whole-group methods of teaching physical education and to provide examples of how it can be implemented in a ...basketball unit and then modified to fit the needs of individuals with visual impairments within that basketball unit. Using PACER is an excellent way for teachers to successfully include all learners by creating a positive environment in which students gain confidence in themselves through task cards and peer assessment, confidence in their class through the formation of teams, and confidence in their teacher through the teacher workshop, teacher assessments, and team rewards.
We present a measurement of the spin-dependent cross sections for the 3He over -->(e over -->,e')X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1< or =Q2< or =0.9 ...GeV2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.
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