The past few decades have seen increased interest in studies examining the welfare of elephants and animal-visitor interactions. One understudied area for both pursuits is the impact of public feeding interactions. Our study examined the effects of public feedings on the general activity of three zoo-housed elephants.
View Article and Find Full Text PDFIn the wild, hippopotamuses spend much of their daily activity in the water. In zoos, it is less clear the extent to which hippos spend time in the water. We examined how much time Woodland Park Zoo's three hippos spent in their outdoor pool, based on: (a) temperature of the pool water, and (b) when the pool water was changed (approximately three times a week).
View Article and Find Full Text PDFRev Sci Instrum
October 2018
Charge-exchange spectroscopy on JET has become particularly challenging with the introduction of the ITER-like wall. The line intensities are weaker and contaminated by many nuisance lines. We have therefore upgraded the instrumentation to improve throughput and allow the simultaneous measurement of impurity and fuel-ion charge exchange by splitting the light between two pairs of imaging spectrometers using dichroic beam splitters.
View Article and Find Full Text PDFCharge exchange spectroscopy has long been a key diagnostic tool for fusion plasmas and is well developed in devices with Carbon Plasma-Facing Components. Operation with the ITER-like wall at JET has resulted in changes to the spectrum in the region of the Carbon charge exchange line at 529.06 nm and demonstrates the need to revise the core charge exchange analysis for this line.
View Article and Find Full Text PDFAn 18-year-old male patient with a history of Ewing sarcoma originally involving the right ilium was evaluated with an FDG PET/CT scan to evaluate the effect of salvage therapy after standard treatment failed and disease progressed to involve the right T12 pedicle. Autologous stem cell transplantation and cyberknife therapy resulted in mixed tumor response, with incidental note made of prominent areas of cortical FDG avidity in the right kidney. These regions demonstrated focal hypoenhancement on the corresponding diagnostic contrast-enhanced CT, which additionally demonstrated peripheral enhancement spanning the length of the right ureter.
View Article and Find Full Text PDFA motional Stark effect (MSE) diagnostic is now installed and operating routinely on the MAST spherical tokamak, with 35 radial channels, spatial resolution of ∼2.5 cm, and time resolution of ∼1 ms at angular noise levels of ∼0.5°.
View Article and Find Full Text PDFRev Sci Instrum
October 2008
In tokamak experiments, equilibrium reconstruction codes are used to calculate the location of the last closed flux surface, to map diagnostic information, and to derive important properties like current density and safety factor. At JET, the equilibrium code EFIT is automatically executed after each discharge. For speed and robustness, intershot EFIT is based on magnetic probe measurements only.
View Article and Find Full Text PDFA multichord motional Stark effect (MSE) system has recently been built on the MAST tokamak. In MAST the pi and sigma lines of the MSE spectrum overlap due to the low magnetic field typical for present day spherical tokamaks. Also, the field curvature results in a large change in the pitch angle over the observation volume.
View Article and Find Full Text PDFResults from the first measurements of a core plasma poloidal rotation velocity (upsilontheta) across internal transport barriers (ITB) on JET are presented. The spatial and temporal evolution of the ITB can be followed along with the upsilontheta radial profiles, providing a very clear link between the location of the steepest region of the ion temperature gradient and localized spin-up of upsilontheta. The upsilontheta measurements are an order of magnitude higher than the neoclassical predictions for thermal particles in the ITB region, contrary to the close agreement found between the determined and predicted particle and heat transport coefficients [K.
View Article and Find Full Text PDFMeasurements of the polarization effects in multimirror experiments by using a dual photoelastic modulator are described. The effect of single and multiple mirrors in polarization measurements in two and three dimensions is discussed, and experimental results show how symmetrical placement of mirrors in three-dimensional geometry can eliminate changes in the polarization. Calibration procedures for a dual photoelastic modulator and potential error sources such as misalignment of analyzer, signal dc offset, and neglect of aperture size are presented.
View Article and Find Full Text PDFA microwave interferometry technique is applied for the first time for detecting a discrete spectrum of Alfvén cascade (AC) eigenmodes excited with fast ions in reversed magnetic shear plasmas of the Joint European Torus. The interferometry measurements of plasma density perturbations associated with ACs show an unprecedented frequency and time resolution superior to that obtained with external magnetic coils. The measurements of ACs are used for monitoring the evolution of the safety factor and density of rational magnetic surfaces in the region of maximum plasma current.
View Article and Find Full Text PDFGamma-ray spectra from nuclear reactions between fusion-born alpha (alpha) particles and Be impurities were measured for the first time in deuterium-tritium plasmas in the Joint European Torus. The time dependence of the measured spectra allowed the determination of the density evolution of fast alpha particles. Correlation between the decay time of the gamma-ray emission and the plasma parameters in different plasma scenarios was established.
View Article and Find Full Text PDFA region of zero current density in the plasma center has been observed in the advanced tokamak scenarios with off-axis lower-hybrid current drive in the JET and JT-60U tokamak experiments. Significantly, the central current density does not become negative, although this is expected based on conventional current diffusion. In this paper, it is shown that the zero central current density and the absence of negative central current can be explained by the influence of a resistive kink magnetohydrodynamic instability.
View Article and Find Full Text PDFSimultaneous current ramping and application of lower hybrid heating and current drive (LHCD) have produced a region with zero current density within measurement errors in the core ( r/a< or =0.2) of JET tokamak optimized shear discharges. The reduction of core current density is consistent with a simple physical explanation and numerical simulations of radial current diffusion including the effects of LHCD.
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