Porcine reproductive and respiratory syndrome virus (PRRSV) in GB pig herds : farm characteristics associated with heterogeneity in seroprevalence

Background: The between- and within-herd variability of porcine reproductive and respiratory syndrome virus (PRRSV) antibodies were investigated in a cross-sectional study of 103 British pig herds conducted 2003–2004. Fifty pigs from each farm were tested for anti-PRRSV antibodies using ELISA. A binomial logistic model was used to investigate management risks for farms with and without pigs with PRRSV antibodies and multilevel statistical models were used to investigate variability in pigs' log ELISA IRPC (relative index × 100) in positive herds. Results: Thirty-five herds (34.0%) were seronegative, 41 (39.8%) were seropositive and 27 (26.2%) were vaccinated. Herds were more likely to be seronegative if they had < 250 sows (OR 3.86 (95% CI 1.46, 10.19)) and if the nearest pig herd was ≥ 2 miles away (OR 3.42 (95% CI 1.29, 9.12)). The mean log IRPC in seropositive herds was 3.02 (range, 0.83 – 5.58). Sixteen seropositive herds had only seropositive adult pigs. In these herds, pigs had -0.06 (95% CI -0.10, -0.01) lower log IRPC for every mile increase in distance to the nearest pig unit, and -0.56 (95% CI -1.02, -0.10) lower log IRPC when quarantine facilities were present. For 25 herds with seropositive young stock and adults, lower log IRPC were associated with isolating purchased stock for ≥ 6 days (coefficient - 0.46, 95% CI -0.81, -0.11), requesting ≥ 48 hours 'pig-free time' from humans (coefficient -0.44, 95% CI -0.79, -0.10) and purchasing gilts (coefficient -0.61, 95% CI -0.92, -0.29). Conclusion: These patterns are consistent with PRRSV failing to persist indefinitely on some infected farms, with fadeout more likely in smaller herds with little/no reintroduction of infectious stock. Persistence of infection may be associated with large herds in pig-dense regions with repeated reintroduction

The control of Corynebacterium pseudotuberculosis infection in sheep flocks : a mathematical model of the impact of vaccination, serological testing, clinical examination and lancing of abscesses

A mathematical model of Corynebacterium pseudotuberculosis infection in sheep flocks was used to evaluate strategies for control and elimination of caseous lymphadenitis (CIA). Control strategies tested were vaccination, serological testing and removal of seropositives, clinical examination and removal of sheep with abscesses, lancing abscesses, and appropriate combinations. Three different infection rates with and without replacement of culled ewes were used to evaluate the control options. Controls were either implemented immediately after infection was detected in a flock or once CIA was at endemic equilibrium, and with different frequencies of examination or testing. Elimination of infection was defined as 99% confidence that no sheep were infected with C. pseudo tuberculosis. The control strategies were evaluated by estimating the reduction in infection or probability of elimination and the number of ewes culled from the flock. Lancing abscesses reduced the prevalence of infection when the initial prevalence was 0.90, but vaccination combined with clinical examination reduced infection rapidly with little impact on lamb productivity. Further research is required to develop a diagnostic test with at least 0.90 specificity and sensitivity under field conditions before any methods of control can be recommended with confidence

Hubble Space Telescope Constraints on the Winds and Astrospheres of Red Giant Stars

We report on an ultraviolet spectroscopic survey of red giants observed by the Hubble Space Telescope, focusing on spectra of the Mg II h & k lines near 2800 A in order to study stellar chromospheric emission, winds, and astrospheric absorption. We focus on spectral types between K2 III and M5 III, a spectral type range with stars that are noncoronal, but possessing strong, chromospheric winds. We find a very tight relation between Mg II surface flux and photospheric temperature, supporting the notion that all K2-M5 III stars are emitting at a basal flux level. Wind velocities (V_w) are generally found to decrease with spectral type, with V_w decreasing from ~40 km/s at K2 III to ~20 km/s at M5 III. We find two new detections of astrospheric absorption, for Sigma Pup (K5 III) and Gamma Eri (M1 III). This absorption signature had previously only been detected for Alpha Tau (K5 III). For the three astrospheric detections the temperature of the wind after the termination shock correlates with V_w, but is lower than predicted by the Rankine-Hugoniot shock jump conditions, consistent with the idea that red giant termination shocks are radiative shocks rather than simple hydrodynamic shocks. A full hydrodynamic simulation of the Gamma Eri astrosphere is provided to explore this further.Comment: 16 pages, 8 figures, to appear in The Astrophysical Journa

Magnetoelectric Jones Dichroism in Atoms

The authors suggest that atomic experiments measuring the interference between magnetic-dipole and electric-field-induced electric-dipole transition amplitudes provide a valuable system to study magnetoelectric Jones effects.Comment: 3 pages, 2 figure

Casimir Effects in Renormalizable Quantum Field Theories

We review the framework we and our collaborators have developed for the study of one-loop quantum corrections to extended field configurations in renormalizable quantum field theories. We work in the continuum, transforming the standard Casimir sum over modes into a sum over bound states and an integral over scattering states weighted by the density of states. We express the density of states in terms of phase shifts, allowing us to extract divergences by identifying Born approximations to the phase shifts with low order Feynman diagrams. Once isolated in Feynman diagrams, the divergences are canceled against standard counterterms. Thus regulated, the Casimir sum is highly convergent and amenable to numerical computation. Our methods have numerous applications to the theory of solitons, membranes, and quantum field theories in strong external fields or subject to boundary conditions.Comment: 27 pp., 11 EPS figures, LaTeX using ijmpa1.sty; email correspondence to R.L. Jaffe ; based on talks presented by the authors at the 5th workshop `QFTEX', Leipzig, September 200

Random harmonic analysis program, L221 (TEV156). Volume 2: Supplemental system design and maintenenace document

Volume 2 of a two volume document is presented. A computer program, L222 (TEV 156), available for execution on the CDC 6600 computer is described. The program is capable of calculating steady-state solutions for linear second-order differential equations due to sinusoidal forcing functions. From this, steady-state solutions, generalized coordinates, and load frequency responses may be determined. Statistical characteristics of loads for the forcing function spectral shape may also be calculated using random harmonic analysis techniques. The particular field of application of the program is the analysis of airplane response and loads due to continuous random air turbulence

Mortality from head injury over four decades in Scotland

Although the causes of head injury, the population at risk and approaches to prevention and treatment are continually evolving, there is little information about how these are reflected in patterns of mortality over time. We used population based comprehensive data uniquely available in Scotland to investigate changes in the total numbers of deaths from 1974 to 2012, as well as the rates of head injury death, from different causes, overall and in relation to age and gender. Total mortality fell from an annual average of 503 to 339 with a corresponding annual decrease in rate from 9.6 to 6.4 per 100,000 population, the decline substantially occurring between 1974 and 1990. Deaths in children fell strikingly but rose in older people. Deaths in males fell to a greater extent than females but remained at a higher rate overall. Initially, a transport accident accounted for most deaths but these fell by 80%, from 325 per year to 65 per year over the 39 year period. Deaths from falling and all other causes did not decline, coming to outnumber transport accident deaths by 1998, which accounts for the overall absence of change in total mortality in recent years. In order to reduce mortality in the future, more effective measures to prevent falls are needed and these strategies will vary in younger adults (where alcohol is often a factor), and in older adults where infirmity can be a cause. In addition, measures to sustain reductions in transport accidents need to be maintained and further developed