Application of Statistical Methods for Improving Models of Intramuscular Percentage Fat Prediction in Live Beef Animals From Real-Time Ultrasound Images

Real-time ultrasound images from the Longissimus dorsi muscle across 11th to 13th ribs of 720 live bulls and steers were acquired over the period of four years. The actual intramuscular percentage of fat (IFAT) was determined using an n-hexane extraction with mean of 4.98%, standard deviation of 2.12%, and range from 1.10% to 14.68%. Image-processing techniques were used to calculate parameters to quantify the image texture patterns. The parameters which showed good correlations with the actual IFAT were used to develop a statistical linear regression model. The accuracy of prediction was very good for the actual IFAT less than or equal to eight (low IFAT group), with root mean square error (RMSE) around 1.0%. However, the model was much less accurate for prediction of IFAT values more than eight (high IFAT group), with RMSE more than 1.5%. One reason for this could be the limited ability of the ultrasound technique to resolve differences in high-IFAT muscles in terms of image texture patterns. Also, this group contained fewer than 10% of the images collected, which may be an inadequate sample. Overall accuracy of prediction was improved by developing different regression models for the low-IFAT and high-IFAT groups. Statistical pattern recognition and classification techniques were applied to “pre-classify” the images into low- or high-IFAT groups before being subjected to regression prediction models. The techniques applied included cluster analysis, discriminant analysis, and classification and regression tree (CART). The classification tree provided the best results with overall classification accuracy around 90% for low- and high-IFAT groups of images. In conclusion, overall accuracy of predicting the IFAT from ultrasound image parameters and regression models can be improved by first isolating the high- IFAT group from low-IFAT group using statistical classification methods

Decoherence in rf SQUID Qubits

We report measurements of coherence times of an rf SQUID qubit using pulsed microwaves and rapid flux pulses. The modified rf SQUID, described by an double-well potential, has independent, in situ, controls for the tilt and barrier height of the potential. The decay of coherent oscillations is dominated by the lifetime of the excited state and low frequency flux noise and is consistent with independent measurement of these quantities obtained by microwave spectroscopy, resonant tunneling between fluxoid wells and decay of the excited state. The oscillation's waveform is compared to analytical results obtained for finite decay rates and detuning and averaged over low frequency flux noise.Comment: 24 pages, 13 figures, submitted to the journal Quantum Information Processin

Fluxoid dynamics in superconducting thin film rings

We have measured the dynamics of individual magnetic fluxoids entering and leaving photolithographically patterned thin film rings of the underdoped high-temperature superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, using a variable sample temperature scanning SQUID microscope. These results can be qualitatively described using a model in which the fluxoid number changes by thermally activated nucleation of a Pearl vortex in, and transport of the Pearl vortex across, the ring wall.Comment: 9 pages, 10 figures, fixed typo

Turbulent mixing of particles under tidal bores: An experimental analysis

A tidal bore develops in an estuary when the tidal range exceeds 4.5-6 m and the estuarine bathymetry amplifies the tidal wave. The bore is an abrupt rise in water depth associated with a discontinuity in velocity and pressure fields at the front. Herein the free-surface properties and the turbulent mixing of light-weight particles were investigated during the passage of tidal bores. The free-surface properties were recorded using a non-intrusive technique, while particle tracking was performed under undular and breaking bores. A basic result was the identification of a broad spectrum of particle trajectories, linked with the existence of large-scale vortical structures. These turbulent structures were responsible for the vertical water mixing as a tidal bore propagates upstream in an estuary. The large-scale eddies were also responsible for the rapid longitudinal dispersion of particulates, such as fish eggs, with some form of preferential motion, depending upon the particle's vertical elevation

Pinch Resonances in a Radio Frequency Driven SQUID Ring-Resonator System

In this paper we present experimental data on the frequency domain response of a SQUID ring (a Josephson weak link enclosed by a thick superconducting ring) coupled to a radio frequency (rf) tank circuit resonator. We show that with the ring weakly hysteretic the resonance lineshape of this coupled system can display opposed fold bifurcations that appear to touch (pinch off). We demonstrate that for appropriate circuit parameters these pinch off lineshapes exist as solutions of the non-linear equations of motion for the system.Comment: 9 pages, 8 figures, Uploaded as implementing a policy of arXiving old paper

Josephson effect between trapped Bose-Einstein condensates

We study the Josephson effect between atomic Bose-Einstein condensates. By drawing on an electrostatic analogy, we derive a semiclassical functional expression for the three-dimensional Josephson coupling energy in terms of the condensate density. Estimates of the capacitive energy and of the Josephson plasma frequency are also given. The effect of dissipation due to the incoherent exchange of normal atoms is analysed. We conclude that coherent Josephson dynamics may already be observable in current experimental systems.Comment: 4 pages, RevTe

Macroscopic resonant tunneling of magnetic flux

We have developed a quantitative theory of resonant tunneling of magnetic flux between discrete macroscopically distinct quantum states in SQUID systems. The theory is based on the standard density-matrix approach. Its new elements include the discussion of the two different relaxation mechanisms that exist for the double-well potential, and description of the ``photon-assisted'' tunneling driven by external rf radiation. It is shown that in the case of coherent flux dynamics, rf radiation should lead to splitting of the peaks of resonant flux tunneling, indicating that the resonant tunneling is a convenient tool for studying macroscopic quantum coherence of flux.Comment: 11 pages, 8 figure

Turbulence measurements in positive surges and bores

A positive surge results from a sudden change in flow that increases the flow depth. New experiments were conducted in a large channel. Most positive surge tests were conducted with a horizontal bed slope, a constant flow rate and uncontrolled flow conditions. The only dependant variable was the downstream gate opening after closure. Detailed turbulence measurements were performed with high-temporal resolution using side-looking acoustic Doppler velocimetry. Two types of positive surge were observed: undular surge for Froude numbers less than 1.7, and weak (breaking) surges above. Instantaneous velocity measurements beneath advancing surges showed a marked effect of the surge passage on the velocity field. Streamwise velocities showed rapid flow deceleration at all vertical elevations. Large fluctuations of longitudinal and transverse velocities were recorded beneath the surges, including some unsteady flow recirculation beneath a weak surge front. Turbulent stresses were deduced from high-pass filtered data. The results showed large normal and tangential Reynolds stresses beneath the surges. A comparison between undular and weak surges suggested some major difference. In weak surge flows, the data showed rapid flow separation beneath the surge front. In undular surges, maximum Reynolds stresses were observed beneath and just before each wave crest behind the leading wave