Dispersal characteristics of swift foxes

From 1997 to 2001, we monitored movements of 109 adult and 114 juvenile swift foxes, Vulpes velox (Say, 1823), at study sites in Colorado, New Mexico, and Texas to determine patterns of dispersal. Significantly more male (93%) than female (58%) juveniles dispersed, and both sexes had similar bimodal dispersal patterns with peaks in September–October and January–February. Adult dispersal occurred more evenly throughout the year, and significantly more male (32%) than female (5%) adults dispersed. Adult males tended to disperse after the death of their mate. Of dispersing foxes with known fates, settlement percentages in new territories were similar between juvenile males and females (40% overall), but they were significantly lower than for adults (89%). All other dispersing foxes with known fates died. Among juvenile females with known fates, similar percentages of philopatric and dispersing foxes reproduced as yearlings (50% overall), so the benefits of dispersal versus philopatry were not clear. Although rarely reported for other species, adult males were an important dispersal cohort in swift foxes (43% of male dispersals and 25% of all dispersals). Because of the female-biased philopatry among swift foxes, dispersal of adult males likely decreased the chances for inbreeding (e.g., father–daughter breeding)

Sources and pathways of trace elements in urban environments: A multielemental qualitative approach

A geochemical model of an urban environment is presented in which multielemental tracers are used to characterise the circulation of trace elements in particulate matter_atmospheric aerosol, street dust and urban soil, within a city

Fate of Escherichia coli O145 present naturally in bovine slurry applied to vegetables before harvest, after washing and simulated wholesale and retail distribution

Aims: To determine the fate of E. coli on vegetables that were processed through commercial wash treatments and stored under simulated retail conditions at 4oC or wholesale at fluctuating ambient temperatures (0-25oC, dependent on season). Methods and Results: Bovine slurry that was naturally contaminated with Escherichia coli O145 was applied without dilution or diluted 1/10 using borehole water to growing potatoes, leeks or carrots. Manure was applied one week prior to harvest to simulate a near-harvest contamination event by manure deposition or an application of contaminated water to simulate a flooding event or irrigation from a contaminated water source. At harvest, crops were contaminated at up to two log cfu/g. Washing transferred E. coli into the water of a flotation tank used for potato washing and did not completely remove all traces of contamination from the crop. Manure contaminated potatoes were observed to contain 0.72 cfu E. coli O145/g after processing and retail storage. Manure-contaminated leeks harboured 0.73 – 1.55 cfu E. coli O145/g after washing and storage. There was no cross contamination when leeks were spray-washed. Washing in an abrasive drum resulted in less than perfect decontamination for manure-contaminated carrots. There were five post-distribution isolations from carrots irrigated with contaminated water 24h prior to harvest. Conclusions: Standard commercial washing and distribution conditions may be insufficient to reliably control human pathogenic E. coli on fresh produce. Significance and Impact: Previous speculation that the cause of a UK foodborne disease outbreak was soil from imperfectly cleaned vegetables is plausible

Symmetry of the Atomic Electron Density in Hartree, Hartree-Fock, and Density Functional Theory

The density of an atom in a state of well-defined angular momentum has a specific finite spherical harmonic content, without and with interactions. Approximate single-particle schemes, such as the Hartree, Hartree-Fock, and Local Density Approximations, generally violate this feature. We analyze, by means of perturbation theory, the degree of this violation and show that it is small. The correct symmetry of the density can be assured by a constrained-search formulation without significantly altering the calculated energies. We compare our procedure to the (different) common practice of spherically averaging the self-consistent potential. Kohn-Sham density functional theory with the exact exchange-correlation potential has the correct finite spherical harmonic content in its density; but the corresponding exact single particle potential and wavefunctions contain an infinite number of spherical harmonics.Comment: 11 pages, 6 figures. Expanded discussion of spherical harmonic expansion of Hartree density. Some typos corrected, references adde

Orbital quantization in the high magnetic field state of a charge-density-wave system

A superposition of the Pauli and orbital coupling of a high magnetic field to charge carriers in a charge-density-wave (CDW) system is proposed to give rise to transitions between subphases with quantized values of the CDW wavevector. By contrast to the purely orbital field-induced density-wave effects which require a strongly imperfect nesting of the Fermi surface, the new transitions can occur even if the Fermi surface is well nested at zero field. We suggest that such transitions are observed in the organic metal $\alpha$-(BEDT-TTF)$_2$KHg(SCN)$_4$ under a strongly tilted magnetic field.Comment: 14 pages including 4 figure

Spin and orbital ordering in double-layered manganites

We study theoretically the phase diagram of the double-layered perovskite manganites taking into account the orbital degeneracy, the strong Coulombic repulsion, and the coupling with the lattice deformation. Observed spin structural changes as the increased doping are explained in terms of the orbital ordering and the bond-length dependence of the hopping integral along $c$-axis. Temperature dependence of the neutron diffraction peak corresponding to the canting structure is also explained. Comparison with the 3D cubic system is made.Comment: 7 figure

Charged Higgs production from SUSY particle cascade decays at the LHC

We analyze the cascade decays of the scalar quarks and gluinos of the Minimal Supersymmetric extension of the Standard Model, which are abundantly produced at the Large Hadron Collider, into heavier charginos and neutralinos which then decay into the lighter ones and charged Higgs particles, and show that they can have substantial branching fractions. The production rates of these Higgs bosons can be much larger than those from the direct production mechanisms, in particular for intermediate values of the parameter $\tan \beta$, and could therefore allow for the detection of these particles. We also discuss charged Higgs boson production from direct two-body top and bottom squark decays as well as from two- and three-body gluino decays.Comment: 30 pages with 10 figures, latex. Uses axodraw.sty and epsfig.st

An assessment of a three-beam Doppler lidar wind profiling method for use in urban areas

Currently there are few observations of the urban wind field at heights other than rooftop level. Remote sensing instruments such as Doppler lidars provide wind speed data at many heights, which would be useful in determining wind loadings of tall buildings, and predicting local air quality. Studies comparing remote sensing with traditional anemometers carried out in flat, homogeneous terrain often use scan patterns which take several minutes. In an urban context the flow changes quickly in space and time, so faster scans are required to ensure little change in the flow over the scan period. We compare 3993 h of wind speed data collected using a three-beam Doppler lidar wind profiling method with data from a sonic anemometer (190 m). Both instruments are located in central London, UK; a highly built-up area. Based on wind profile measurements every 2 min, the uncertainty in the hourly mean wind speed due to the sampling frequency is 0.05–0.11 m s−1. The lidar tended to overestimate the wind speed by ≈0.5 m s−1 for wind speeds below 20 m s−1. Accuracy may be improved by increasing the scanning frequency of the lidar. This method is considered suitable for use in urban areas

Virus shapes and buckling transitions in spherical shells

We show that the icosahedral packings of protein capsomeres proposed by Caspar and Klug for spherical viruses become unstable to faceting for sufficiently large virus size, in analogy with the buckling instability of disclinations in two-dimensional crystals. Our model, based on the nonlinear physics of thin elastic shells, produces excellent one parameter fits in real space to the full three-dimensional shape of large spherical viruses. The faceted shape depends only on the dimensionless Foppl-von Karman number \gamma=YR^2/\kappa, where Y is the two-dimensional Young's modulus of the protein shell, \kappa is its bending rigidity and R is the mean virus radius. The shape can be parameterized more quantitatively in terms of a spherical harmonic expansion. We also investigate elastic shell theory for extremely large \gamma, 10^3 < \gamma < 10^8, and find results applicable to icosahedral shapes of large vesicles studied with freeze fracture and electron microscopy.Comment: 11 pages, 12 figure

Neutrino Masses with "Zero Sum" Condition: mν1+mν2+mν3=0m_{\nu_1} + m_{\nu_2} + m_{\nu_3} = 0

It is well known that the neutrino mass matrix contains more parameters than experimentalists can hope to measure in the foreseeable future even if we impose CP invariance. Thus, various authors have proposed ansatzes to restrict the form of the neutrino mass matrix further. Here we propose that $m_{\nu_1} + m_{\nu_2} + m_{\nu_3} = 0$; this ``zero sum'' condition can occur in certain class of models, such as models whose neutrino mass matrix can be expressed as commutator of two matrices. With this condition, the absolute neutrino mass can be obtained in terms of the mass-squared differences. When combined with the accumulated experimental data this condition predicts two types of mass hierarchies, with one of them characterized by $m_{\nu_3} \approx -2m_{\nu_1} \approx -2 m_{\nu_2} \approx 0.063$ eV, and the other by $m_{\nu_1} \approx -m_{\nu_2} \approx 0.054$ eV and $m_{\nu_3} \approx 0.0064$ eV. The mass ranges predicted is just below the cosmological upper bound of 0.23 eV from recent WMAP data and can be probed in the near future. We also point out some implications for direct laboratory measurement of neutrino masses, and the neutrino mass matrix.Comment: Latex 12 pages. No figures. New references adde