Electric and magnetic response to the continuum for A=7 isobars in a dicluster model

Mirror isobars $^7$Li and $^7$Be are investigated in a dicluster model. The magnetic dipole moments and the magnetic dipole response to the continuum are calculated in this framework. The magnetic contribution is found to be small with respect to electric dipole and quadrupole excitations even at astrophysical energies, at a variance with the case of deuteron. Energy weighted molecular sum rules are evaluated and a formula for the molecular magnetic dipole sum rule is found which matches the numerical calculations. Cross-sections for photo-dissociation and radiative capture as well as the S-factor for reactions of astrophysical significance are calculated with good agreement with known experimental data.Comment: Accepted in EPJ

The supersymmetric Penrose transform in six dimensions

We give a supersymmetric extension to the six-dimensional Penrose transform and give an integral formula for the on-shell (0, 2) supermultiplet. The relationship between super fields on space-time and twistor space is clarified and the space-time superfield constraint equations are derived from the geometry of supertwistor space. We also explain the extension to more general (0,n) supermultiplets and give twistor actions for these theories.Comment: 20 page

Critical Evaluation and Compilation of Viscosity and Diffusivity Data Semiannual Status Report No. 1, Jul. 1 - Dec. 31, 1965

Compilation and evaluation of diffusivity and viscosity data on gas and liquid turbulent flow system

Vibrating quantum billiards on Riemannian manifolds

Quantum billiards provide an excellent forum for the analysis of quantum chaos. Toward this end, we consider quantum billiards with time-varying surfaces, which provide an important example of quantum chaos that does not require the semiclassical ($\hbar \longrightarrow 0$) or high quantum-number limits. We analyze vibrating quantum billiards using the framework of Riemannian geometry. First, we derive a theorem detailing necessary conditions for the existence of chaos in vibrating quantum billiards on Riemannian manifolds. Numerical observations suggest that these conditions are also sufficient. We prove the aforementioned theorem in full generality for one degree-of-freedom boundary vibrations and briefly discuss a generalization to billiards with two or more degrees-of-vibrations. The requisite conditions are direct consequences of the separability of the Helmholtz equation in a given orthogonal coordinate frame, and they arise from orthogonality relations satisfied by solutions of the Helmholtz equation. We then state and prove a second theorem that provides a general form for the coupled ordinary differential equations that describe quantum billiards with one degree-of-vibration boundaries. This set of equations may be used to illustrate KAM theory and also provides a simple example of semiquantum chaos. Moreover, vibrating quantum billiards may be used as models for quantum-well nanostructures, so this study has both theoretical and practical applications.Comment: 23 pages, 6 figures, a few typos corrected. To appear in International Journal of Bifurcation and Chaos (9/01

A learning object success story

This paper outlines an approach to designing a course entirely in learning objects. It provides a theoretical basis for the design and then presents evaluation data from a master’s level course using this design. It also describes several re-uses of the learning objects on other courses and in different contexts. Each learning object is conceived as a whole learning experience, thus avoiding many of the problems associated with assembling components of disparate kinds

A New Look at Neon-C and SEP-Neon

Studies of the isotopic composition of neon in lunar soils, meteorites, and interplanetary dust particles have revealed several distinct components. In addition to implanted solar wind, which has a ^(20)Ne/^(22)Ne-abundance ratio of 13.7, there is an additional component with ^(20)Ne/^(22)Ne≈11.2, originally attributed to higher-energy solar energetic particles. Using data from the Advanced Composition Explorer, we have measured the fluence of solar wind, suprathermal particles, solar energetic particles and cosmic rays from ~0.3 keV/nucleon to ~300 MeV/nucleon over an extended time period. We use these measured spectra to simulate the present-day depth distribution of Ne isotopes implanted in the lunar soil. We find that the suprathermal tail of the solar wind, extending from a few keV/nucleon to several MeV/nucleon with a power law spectrum, can produce ^(20)Ne/^(22)Ne abundance ratios in the lunar soil that are similar to the measured composition, although there remain significant questions about the extent to which the present-day intensity of suprathermal ions is sufficient to explain the lunar observations

Abundances of Suprathermal Heavy Ions in CIRs during the Minimum of Solar Cycle 23

In this paper we examine the elemental composition of the 0.1-1 MeV/nucleon interplanetary heavy ions from H to Fe in corotating interaction regions (CIRs) measured by the SIT (Suprathermal Ion Telescope) instrument. We use observations taken on board the STEREO spacecraft from January 2007 through December 2010, which included the unusually long solar minimum following solar cycle 23. During this period instruments on STEREO observed more than 50 CIR events making it possible to investigate CIR ion abundances during solar minimum conditions with unprecedented high statistics. The observations reveal annual variations of relative ion abundances in the CIRs during the 2007-2008 period as indicated by the He/H, He/O and Fe/O elemental ratios. We discuss possible causes of the variability in terms of the helium focusing cone passage and heliolatitude dependence. The year 2009 was very quiet in CIR event activity. In 2010 the elemental composition in CIRs were influenced by sporadic solar energetic particle (SEP) events. The 2010 He/H and He/O abundance ratios in CIRs show large event to event variations with values resembling the SEP-like composition. This finding points out that the suprathermal SEPs could be the source population for CIR acceleration.Comment: accepted for publication in Solar Physic

System design study for an optimal remote oculometer for use in operational aircraft

System design of optimal remote oculometer for use in operational aircraf

Arkansas Wheat Cultivar Performance Tests 2013-2014

Wheat cultivar performance tests are conducted each year in Arkansas by the Arkansas Agricultural Experiment Station, Department of Crop, Soil and Environmental Sciences. The tests provide information to companies developing cultivars and/or marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating cultivar recommendations for small-grain producers