Static axisymmetric spacetimes with non-generic world-line SUSY

The conditions for the existence of Killing-Yano tensors, which are closely related to the appearance of non-generic world-line SUSY, are presented for static axisymmetric spacetimes. Imposing the vacuum Einstein equation, the set of solutions admitting Killing-Yano tensors is considered. In particular, it is shown that static, axisymmetric and asymptotically flat vacuum solutions admitting Killing-Yano tensors are only the Schwarzschild solution.Comment: 10 pages (RevTeX), TIT/HEP-253/COSMO-4

Classical gravitational spin-spin interaction

I obtain an exact, axially symmetric, stationary solution of Einstein's equations for two massless spinning particles. The term representing the spin-spin interaction agrees with recently published approximate work. The spin-spin force appears to be proportional to the inverse fourth power of the coordinate distance between the particles.Comment: six pages, no figures, journal ref:accepted for Classical and Quantum Gravit

National Transonic Facility: A review of the operational plan

The proposed National Transonic Facility (NTF) operational plan is reviewed. The NTF will provide an aerodynamic test capability significantly exceeding that of other transonic regime wind tunnels now available. A limited number of academic research program that might use the NTF are suggested. It is concluded that the NTF operational plan is useful for management, technical, instrumentation, and model building techniques available in the specialized field of aerodynamic analysis and simulation. It is also suggested that NASA hold an annual conference to discuss wind tunnel research results and to report on developments that will further improve the utilization and cost effectiveness of the NTF and other wind tunnels

Bound States in Sharply Bent Waveguides: Analytical and Experimental Approach

Quantum wires and electromagnetic waveguides possess common features since their physics is described by the same wave equation. We exploit this analogy to investigate experimentally with microwave waveguides and theoretically with the help of an effective potential approach the occurrence of bound states in sharply bent quantum wires. In particular, we compute the bound states, study the features of the transition from a bound to an unbound state caused by the variation of the bending angle and determine the critical bending angles at which such a transition takes place. The predictions are confirmed by calculations based on a conventional numerical method as well as experimental measurements of the spectra and electric field intensity distributions of electromagnetic waveguides

The structure of the QED-Vacuum and Electron-Positron Pair Production in Super-Intense, pulsed Laser Fields

We discuss electron-positron pair-production by super-intense, short laser pulses off the physical vacuum state locally deformed by (stripped) nuclei with large nuclear charges. Consequences of non-perturbative vacuum polarisation resulting from such a deformation are shortly broached. Production probabilities per pulse are calculated.Comment: 10 pages, 1 figure, submitted to Journal of Physics

Caragana Establishment, Survival and Regeneration in the Black Hills, South Dakota

The purpose of this study was to determine the adaptability and potential wildlife value of Caragana also known as Siberian peashrub for establishment, survival, growth, regeneration, and nutritional qualities. This study was initiated in 1968 in the Black Hills, South Dakota on the McVey Burn (1939), within an open stand of a ponderosa pine forest. Bare rootstock was planted in 1968, and after 35 years survival was 74 percent. Average height was 3 m (10 feet) and plants did regenerate by seed bt did not expand into adjacent habitat. Ideal growing condition evaluated at 35 years, was in a closed tree canopy with 35 percent overstory and basal area 17.7 m2/ha (77 ft2/ acre). Open growing conditions was had exposed areas, canopy cover 17 percent and basal area 5.4 m2/ha (24 ft2/acre). Tree overstory cover on North facing slopes was approximately 2 times greater than on more open south facing slopes. Caragana has not shown signs of spreading from original planting sites. A model developed for habitat assignment defining Closed and Open tree overstory cover for growth, regeneration, and establishment for future sites was 90 percent accurate. Utilization of Caragana by deer based on volume (length x width x height) was 77 percent, 12 years after establishment, with greatest use on south facing slopes. Nutritional qualities of Caragana are generally greater than native shrubs for winter use, with only phosphorous being marginal. The adaptability of Caragana and its qualities makes this browse species suitable for white-tailed deer use for winters. Plantations of Caragana in key wintering areas for white-tailed deer on south facing slopes with Open tree overstory cover and low basal area is recommended for restoration on over browsed ranges

Difficulty of elderly SCI subjects to translate motor recovery -"body function"- into activity of daily living

The objective of this retrospective analysis was to determine whether outcome of body functions and activities as well as length of stay of inpatient rehabilitation is related to age in patients with traumatic spinal cord injury (SCI). Data were collected from a European network of 17 SCI rehabilitation centers (EM-SCI) and 237 traumatic SCI subjects were included. Assessments were performed at one, six and twelve months after SCI. The measures analyzed were: motor score according to the American Spinal Injury Association, Spinal Cord Independence Measure (SCIM), gait speed and length of stay. Correlation analysis was applied to quantify the association between age and change in the outcome measures. A positive relationship was found between age and neurological recovery in both the first and second 6 month- period of assessment. A negative relationship was found between age and change in SCIM in the second six month period after SCI. A negative relationship between age and gait speed was observed in the first half year. Length of stay was not associated with age. It is concluded that age is an important determining factor for functional outcome after SCI and that elderly patients have difficulties in translating an improvement in neurological outcome into functional changes. Therefore, rehabilitation approaches should focus on functional training in elderly subjects

Generalized Killing equations and Taub-NUT spinning space

The generalized Killing equations for the configuration space of spinning particles (spinning space) are analysed. Simple solutions of the homogeneous part of these equations are expressed in terms of Killing-Yano tensors. The general results are applied to the case of the four-dimensional euclidean Taub-NUT manifold.Comment: 10 pages, late

Avian pectoral muscle size rapidly tracks body mass changes during flight, fasting and fuelling

We used ultrasonic imaging to monitor short-term changes in the pectoral muscle size of captive red knots Calidris canutus. Pectoral muscle thickness changed rapidly and consistently in parallel with body mass changes caused by flight, fasting;and fuelling. Four knots hew repeatedly for 10h periods in a wind tunnel. Over this period, pectoral muscle thickness decreased in parallel with the decrease in body mass. The change in pectoral muscle thickness during flight wats indistinguishable from that during periods of natural and experimental fasting and fuelling, The body-mass-related variation in pectoral muscle thickness between and within individuals was not related to the amount of Right, indicating that changes in avian muscle do not require power-training as in mammals. Our study suggests that it is possible for birds to consume and replace their flight muscles on a time scale short enough to allow these muscles to be used as part of the energy supply for migratory flight. The adaptive significance of the changes in pectoral muscle mass cannot be explained by reproductive needs since our knots were in the early winter phase of their annual cycle. Instead, pectoral muscle mass changes may reflect (i) the breakdown of protein during heavy exercise and its subsequent restoration, (ii) the regulation of flight capacity to maintain optimal flight performance when body mass varies, or (iii) the need for a particular protein:fat ratio in winter survival stores.</p