Magnon dispersion and thermodynamics in CsNiF_3

We present an accurate transfer matrix renormalization group calculation of the thermodynamics in a quantum spin-1 planar ferromagnetic chain. We also calculate the field dependence of the magnon gap and confirm the accuracy of the magnon dispersion derived earlier through an 1/n expansion. We are thus able to examine the validity of a number of previous calculations and further analyze a wide range of experiments on CsNiF_3 concerning the magnon dispersion, magnetization, susceptibility, and specific heat. Although it is not possible to account for all data with a single set of parameters, the overall qualitative agreement is good and the remaining discrepancies may reflect departure from ideal quasi-one-dimensional model behavior. Finally, we present some indirect evidence to the effect that the popular interpretation of the excess specific heat in terms of sine-Gordon solitons may not be appropriate.Comment: 9 pages 10 figure

Dynamics of topological solitons in two-dimensional ferromagnets

Dynamical topological solitons are studied in classical two-dimensional Heisenberg easy-axis ferromagnets. The properties of such solitons are treated both analytically in the continuum limit and numerically by spin dynamics simulations of the discrete system. Excitation of internal mode causes orbital motion. This is confirmed by simulations.Comment: LaTeX, 15 pages, 6 figure

Magnetic excitations in the spin-1 anisotropic antiferromagnet NiCl2−4SC(NH2)2NiCl_2-4SC(NH_2)_2

The spin-1 anisotropic antiferromagnet NiCl_2-4SC(NH2)_2 exhibits a field-induced quantum phase transition that is formally analogous to Bose-Einstein condensation. Here we present results of systematic high-field electron spin resonance (ESR) experimental and theoretical studies of this compound with a special emphasis on single-ion two-magnon bound states. In order to clarify some remaining discrepancies between theory and experiment, the frequency-field dependence of magnetic excitations in this material is reanalyzed. In particular, a more comprehensive interpretation of the experimental signature of single-ion two-magnon bound states is shown to be fully consistent with theoretical results. We also clarify the structure of the ESR spectrum in the so-called intermediate phase.Comment: 9 pages, 10 figure

Effects of relative submergence on flow and sediment patterns around clasts

River morphodynamics and sediment transportMechanics of sediment transpor

Chemosensory genes identified in the antennal transcriptome of the blowfly Calliphora stygia

© 2015 Leitch et al. Background: Blowflies have relevance in areas of forensic science, agriculture, and medicine, primarily due to the ability of their larvae to develop on flesh. While it is widely accepted that blowflies rely heavily on olfaction for identifying and locating hosts, there is limited research regarding the underlying molecular mechanisms. Using next generation sequencing (Illumina), this research examined the antennal transcriptome of Calliphora stygia (Fabricius) (Diptera: Calliphoridae) to identify members of the major chemosensory gene families necessary for olfaction. Results: Representative proteins from all chemosensory gene families essential in insect olfaction were identified in the antennae of the blowfly C. stygia, including 50 odorant receptors, 22 ionotropic receptors, 21 gustatory receptors, 28 odorant binding proteins, 4 chemosensory proteins, and 3 sensory neuron membrane proteins. A total of 97 candidate cytochrome P450s and 39 esterases, some of which may act as odorant degrading enzymes, were also identified. Importantly, co-receptors necessary for the proper function of ligand-binding receptors were identified. Putative orthologues for the conserved antennal ionotropic receptors and candidate gustatory receptors for carbon dioxide detection were also amongst the identified proteins. Conclusions: This research provides a comprehensive novel resource that will be fundamental for future studies regarding blowfly olfaction. Such information presents potential benefits to the forensic, pest control, and medical areas, and could assist in the understanding of insecticide resistance and targeted control through cross-species comparisons

Vortex Rings and Lieb Modes in a Cylindrical Bose-Einstein Condensate

We present a calculation of a solitary wave propagating along a cylindrical Bose-Einstein trap, which is found to be a hybrid of a one-dimensional (1D) soliton and a three-dimensional (3D) vortex ring. The calculated energy-momentum dispersion exhibits characteristics similar to those of a mode proposed sometime ago by Lieb within a 1D model, as well as some rotonlike features.Comment: 4 pages, 4 figure

Functional status of persons with chronic fatigue syndrome in the Wichita, Kansas, population

BACKGROUND: Scant research has adequately addressed the impact of chronic fatigue syndrome on patients' daily activities and quality of life. Enumerating specific problems related to quality of life in chronic fatigue syndrome patients can help us to better understand and manage this illness. This study addresses issues of functional status in persons with chronic fatigue syndrome and other fatiguing illnesses in a population based sample, which can be generalized to all persons with chronic fatigue. METHODS: We conducted a random telephone survey in Wichita, Kansas to identify persons with chronic fatigue syndrome and other fatiguing illnesses. Respondents reporting severe fatigue of at least 1 month's duration and randomly selected non-fatigued respondents were asked to participate in a detailed telephone interview. Participants were asked about symptoms, medical and psychiatric illnesses, and about physical, social, and recreational functioning. Those meeting the 1994 chronic fatigue syndrome case definition, as determined on the basis of their telephone responses, were invited for clinical evaluation to confirm a diagnosis of chronic fatigue syndrome. For this analysis, we evaluated unemployment due to fatigue, number of hours per week spent on work, chores, and other activities (currently and prior to the onset of fatigue), and energy level. RESULTS: There was no difference between persons with chronic fatigue syndrome and persons with a chronic fatigue syndrome-like illness that could be explained by a medical or psychiatric condition for any of the outcomes we measured except for unemployment due to fatigue (15% vs. 40%, P < .01). Persons with chronic fatigue syndrome and other fatiguing illnesses had substantially less energy and spent less time on hobbies, schooling, or volunteer work than did non-fatigued controls (P < .01). CONCLUSIONS: Persons with chronic fatigue syndrome are as impaired as persons whose fatigue could be explained by a medical or psychiatric condition, and they have less energy than non-fatigued controls

Thermodynamics of the spin-flop transition in a quantum XYZ chain

A special limit of an antiferromagnetic XYZ chain was recently shown to exhibit interesting bulk as well as surface spin-flop transitions at T=0. Here we provide a complete calculation of the thermodynamics of the bulk transition using a transfer-matrix-renormalization-group (TMRG) method that addresses directly the thermodynamic limit of quantum spin chains. We also shed some light on certain spinwave anomalies at low temperature predicted earlier by Johnson and Bonner.Comment: 4 pages, 6 Postscript figure