Analysing the relationship between ectomycorrhizal infection and forest decline using marginal models

This statistical survey originates from the problem of discovering which relationship exists between root ectomycorrhizal infection and health status of forest plants. The sampling scheme takes observations from roots that come from sectors around the tree resulting in a hierarchical association structure of the observations. Marginal regression models are used to analyze the mean effect of the ectomycorrhizal state on a response variable proxy for the health degree of the plants

Measurements of quasi-particle tunneling in the nu = 5/2 fractional quantum Hall state

Some models of the 5/2 fractional quantum Hall state predict that the quasi-particles, which carry the charge, have non-Abelian statistics: exchange of two quasi-particles changes the wave function more dramatically than just the usual change of phase factor. Such non-Abelian statistics would make the system less sensitive to decoherence, making it a candidate for implementation of topological quantum computation. We measure quasi-particle tunneling as a function of temperature and DC bias between counter-propagating edge states. Fits to theory give e*, the quasi-particle effective charge, close to the expected value of e/4 and g, the strength of the interaction between quasi-particles, close to 3/8. Fits corresponding to the various proposed wave functions, along with qualitative features of the data, strongly favor the Abelian 331 state

MF2315

Melvin Hunt et al, Making ground beef patties and sausage safer, Kansas State University, January 1998

On the mean-field spherical model

Exact solutions are obtained for the mean-field spherical model, with or without an external magnetic field, for any finite or infinite number N of degrees of freedom, both in the microcanonical and in the canonical ensemble. The canonical result allows for an exact discussion of the loci of the Fisher zeros of the canonical partition function. The microcanonical entropy is found to be nonanalytic for arbitrary finite N. The mean-field spherical model of finite size N is shown to be equivalent to a mixed isovector/isotensor sigma-model on a lattice of two sites. Partial equivalence of statistical ensembles is observed for the mean-field spherical model in the thermodynamic limit. A discussion of the topology of certain state space submanifolds yields insights into the relation of these topological quantities to the thermodynamic behavior of the system in the presence of ensemble nonequivalence.Comment: 21 pages, 5 figure

Ground State Spin Oscillations of a Two-Electron Quantum Dot in a Magnetic Field

Crossings between spin-singlet and spin-triplet lowest states are analyzed within the model of a two-electron quantum dot in a perpendicular magnetic field. The explicit expressions in terms of the magnetic field, the magnetic quantum number $m$ of the state and the dimensionless dot size for these crossings are found.Comment: 8 pages, 2 figures (PS files). The paper will appear in Journal of Physics: Condensed Matter, volume 11, issue 11 (cover date 22 March 1999) on pages 83 - 8

Effects of freezing pork chops on warner-bratzler shear force and cookery traits

Eighty-one boneless pork loins were used to determine the influence of freezing and pH on Warner-Bratzler shear force (WBS) values and cookery traits. Chops with lower pH (<5.5 to 5.5) had higher cooking losses than chops with intermediate pH (5.7 to 5.9) and higher pH (6.0 to >6.2). Similar to cooking losses, total moisture losses decreased with increased pH. Frozen chops had lower WBS values (more tender) than fresh chops. However, fresh chops had a higher total yield (lower moisture loss) than frozen chops

Correlation Effects on Transport Through Few-Electrons Systems

We study lateral tunneling through a quantum box including electron-electron interactions in the presence of a magnetic field which breaks single particle degeneracies. The conductance at zero temperature as a function of the Fermi energy in the leads consists of a set of peaks related to changing by one the electron occupancy in the box. We find that the position and heights of the peaks are controlled by many-body effects. We compute the conductance up to 8 electrons for several cases where correlation effects dominate. In the range of intermediate fields spin selection rules quench some peaks. At low and high fields the behavior of the conductance as a function of the number of electrons is very different due to big changes in the many-body ground state wavefunctions.Comment: 9 pages, 2 postscript figures, Latex 3.1

Effect of Quantum Confinement on Electron Tunneling through a Quantum Dot

Employing the Anderson impurity model, we study tunneling properties through an ideal quantum dot near the conductance minima. Considering the Coulomb blockade and the quantum confinement on an equal footing, we have obtained current contributions from various types of tunneling processes; inelastic cotunneling, elastic cotunneling, and resonant tunneling of thermally activated electrons. We have found that the inelastic cotunneling is suppressed in the quantum confinement limit, and thus the conductance near its minima is determined by the elastic cotunneling at low temperature ($k_BT \ll \Gamma$, $\Gamma$: dot-reservoir coupling constant), or by the resonant tunneling of single electrons at high temperature ($k_BT \gg \Gamma$).Comment: 11 pages Revtex, 2 Postscript figures, To appear in Phys.Rev.

Effects of pH and location within a loin on pork quality

Eighty-one boneless pork loins were used to determine the influence of pH on quality characteristics. With increasing loin pH, instrumental values for L* (lightness) and b* (yellowness) of loins and chops decreased, and cooking losses of chops before 0 d and after 1 d of retail display also decreased. The pH had no effects on package losses or Warner-Bratzler shear force values of chops. Center loin chops (0 d and 1 d) had higher ratios of reflectance than blade and sirloin chops. Sirloin chops had higher ratio of reflectance than blade chops. Center loin chops had lower package losses than blade and sirloin chops. Blade chops had lower (more tender) WBS values than center loin and sirloin chops. Measuring loin pH can predict instrumental color (L*and b*) values as well as cooking losses

Energy Dependent Tunneling in a Quantum Dot

We present measurements of the rates for an electron to tunnel on and off a quantum dot, obtained using a quantum point contact charge sensor. The tunnel rates show exponential dependence on drain-source bias and plunger gate voltages. The tunneling process is shown to be elastic, and a model describing tunneling in terms of the dot energy relative to the height of the tunnel barrier quantitatively describes the measurements.Comment: 4 pages, 4 figure