Use of vaccines and factors associated with their uptake variability in dogs, cats and rabbits attending a large sentinel network of veterinary practices across Great Britain

Vaccination remains a mainstay of companion animal population health. However, how vaccine use at a population level complies with existing guidelines is unknown. Here we use electronic health records to describe vaccination in dogs, cats and rabbits attending a large sentinel network of UK veterinary practices. In total, 77.9% (95% CI: 77.6-78.1) of animals had recorded vaccinations. The percentage of animals with recorded vaccinations was higher in dogs, neutered animals, in insured dogs and cats and in purebred dogs. Vaccination rates varied in different regions of Great Britain in all species. Dogs and cats belonging to owners living in less deprived areas of England and Scotland were more likely to be recorded as vaccinated. In the vaccinated population, cats received more core vaccines per year of life (0.86) than dogs (0.75), with feline leukaemia vaccines almost as frequent as core vaccines. In dogs, leptospira vaccines were more frequent than core vaccines. This descriptive study suggests a substantial proportion of animals are not benefiting from vaccine protection. For the first time, we identify potential factors associated with variations in recorded vaccination frequency, providing a critical baseline against which to monitor future changes in companion animal vaccination and evidence to inform future targeted health interventions

The quantum vacuum at the foundations of classical electrodynamics

In the classical theory of electromagnetism, the permittivity and the permeability of free space are constants whose magnitudes do not seem to possess any deeper physical meaning. By replacing the free space of classical physics with the quantum notion of the vacuum, we speculate that the values of the aforementioned constants could arise from the polarization and magnetization of virtual pairs in vacuum. A classical dispersion model with parameters determined by quantum and particle physics is employed to estimate their values. We find the correct orders of magnitude. Additionally, our simple assumptions yield an independent estimate for the number of charged elementary particles based on the known values of the permittivity and the permeability, and for the volume of a virtual pair. Such interpretation would provide an intriguing connection between the celebrated theory of classical electromagnetism and the quantum theory in the weak field limit.Comment: Accepted in Applied Physics B: Special Issue for the 50 years of the laser. Comments are welcome

Percolation in Directed Scale-Free Networks

Many complex networks in nature have directed links, a property that affects the network's navigability and large-scale topology. Here we study the percolation properties of such directed scale-free networks with correlated in- and out-degree distributions. We derive a phase diagram that indicates the existence of three regimes, determined by the values of the degree exponents. In the first regime we regain the known directed percolation mean field exponents. In contrast, the second and third regimes are characterized by anomalous exponents, which we calculate analytically. In the third regime the network is resilient to random dilution, i.e., the percolation threshold is p_c->1.Comment: Latex, 5 pages, 2 fig

Survival probability of a diffusing particle in the presence of Poisson-distributed mobile traps

The problem of a diffusing particle moving among diffusing traps is analyzed in general space dimension d. We consider the case where the traps are initially randomly distributed in space, with uniform density rho, and derive upper and lower bounds for the probability Q(t) (averaged over all particle and trap trajectories) that the particle survives up to time t. We show that, for 1<=d<2, the bounds converge asymptotically to give $Q(t) \sim exp(-\lambda_d t^{d/2})$ where $\lambda_d = (2/\pi d) sin(\pi d/2) (4\pi D)^{d/2} \rho$ and D is the diffusion constant of the traps, and that $Q(t) \sim exp(- 4\pi\rho D t/ln t)$ for d=2. For d>2 bounds can still be derived, but they no longer converge for large t. For 1<=d<=2, these asymptotic form are independent of the diffusion constant of the particle. The results are compared with simulation results obtained using a new algorithm [V. Mehra and P. Grassberger, Phys. Rev. E v65 050101 (2002)] which is described in detail. Deviations from the predicted asymptotic forms are found to be large even for very small values of Q(t), indicating slowly decaying corrections whose form is consistent with the bounds. We also present results in d=1 for the case where the trap densities on either side of the particle are different. For this case we can still obtain exact bounds but they no longer converge.Comment: 13 pages, RevTeX4, 6 figures. Figures and references updated; equations corrected; discussion clarifie

Nonequilibrium transitions in complex networks: a model of social interaction

We analyze the non-equilibrium order-disorder transition of Axelrod's model of social interaction in several complex networks. In a small world network, we find a transition between an ordered homogeneous state and a disordered state. The transition point is shifted by the degree of spatial disorder of the underlying network, the network disorder favoring ordered configurations. In random scale-free networks the transition is only observed for finite size systems, showing system size scaling, while in the thermodynamic limit only ordered configurations are always obtained. Thus in the thermodynamic limit the transition disappears. However, in structured scale-free networks, the phase transition between an ordered and a disordered phase is restored.Comment: 7 pages revtex4, 10 figures, related material at http://www.imedea.uib.es/PhysDept/Nonlinear/research_topics/Social

Statistical mechanics of topological phase transitions in networks

We provide a phenomenological theory for topological transitions in restructuring networks. In this statistical mechanical approach energy is assigned to the different network topologies and temperature is used as a quantity referring to the level of noise during the rewiring of the edges. The associated microscopic dynamics satisfies the detailed balance condition and is equivalent to a lattice gas model on the edge-dual graph of a fully connected network. In our studies -- based on an exact enumeration method, Monte-Carlo simulations, and theoretical considerations -- we find a rich variety of topological phase transitions when the temperature is varied. These transitions signal singular changes in the essential features of the global structure of the network. Depending on the energy function chosen, the observed transitions can be best monitored using the order parameters Phi_s=s_{max}/M, i.e., the size of the largest connected component divided by the number of edges, or Phi_k=k_{max}/M, the largest degree in the network divided by the number of edges. If, for example the energy is chosen to be E=-s_{max}, the observed transition is analogous to the percolation phase transition of random graphs. For this choice of the energy, the phase-diagram in the [,T] plane is constructed. Single vertex energies of the form E=sum_i f(k_i), where k_i is the degree of vertex i, are also studied. Depending on the form of f(k_i), first order and continuous phase transitions can be observed. In case of f(k_i)=-(k_i+c)ln(k_i), the transition is continuous, and at the critical temperature scale-free graphs can be recovered.Comment: 12 pages, 12 figures, minor changes, added a new refernce, to appear in PR

Ballistic Localization in Quasi-1D Waveguides with Rough Surfaces

Structure of eigenstates in a periodic quasi-1D waveguide with a rough surface is studied both analytically and numerically. We have found a large number of "regular" eigenstates for any high energy. They result in a very slow convergence to the classical limit in which the eigenstates are expected to be completely ergodic. As a consequence, localization properties of eigenstates originated from unperturbed transverse channels with low indexes, are strongly localized (delocalized) in the momentum (coordinate) representation. These eigenstates were found to have a quite unexpeted form that manifests a kind of "repulsion" from the rough surface. Our results indicate that standard statistical approaches for ballistic localization in such waveguides seem to be unappropriate.Comment: 5 pages, 4 figure

Análisis de daño cromosomico espontáneo e inducido por mutágenos químicos en linfocitos de sangre periférica de personal aeronáutico de flota internacional

Se analizó el daño citogenético en linfocitos de sangre periférica de personal aeronáutico de flota internacional de la Argentina con el fin de evaluar los efectos de la radiación cósmica sobre el material genético de dicho grupo de individuos y determinar su sensibilidad a mutágenos químicos, como una primera aproxima­ción a determinar riesgo de cáncer en dicha población. Mediante técnicas citogenéticas convencionales, se determinó la frecuencia de aberraciones cromosómicas (AC) “espontáneas” e inducidas in vitro por bleomicina (BLM) en las etapas G0 y G2 del ciclo celular y de intercambios de cromátidas hermanas (ICH) espon­táneos e inducidos por estreptonigrina (EN) en linfocitos de sangre periférica de 21 tripulantes de flota inter­nacional (pilotos y azafatas) y 18 individuos controles. El personal aeronáutico presentó una frecuencia 3,5 veces mayor de AC “espontáneas” y 2 veces mayor de AC inducidas por BLM en la etapa G0 del ciclo celu­lar que los individuos de la población control. Estos resultados permiten sugerir que el personal aeronáutico de flota internacional de nuestro país debería ser considerado “grupo laboralmente expuesto a la radiación” y que el ensayo de BLM G0 sería el más apropiado para determinar sensibilidad a mutágenos en personal aeronáutico de flota internacional.Universidad Nacional de La Plat

NR4A2 Mutations Can Cause Intellectual Disability and Language Impairment With Persistent Dystonia-Parkinsonism

TheNR4A2/NURR1gene (MIM*601828) has recently been associated with autosomal-dominantearly-onset dystonia-parkinsonism with intellectual disability.1NR4A2codifies for a nuclear tran-scription factor and is expressed mainly in the substantia nigra, ventral tegmental area, and limbicareas.2To date, 14 different alterations inNR4A2have been described associated with variousclinical phenotypes, mainly with neurodevelopment disorders (table e-1, links.lww.com/NXG/A371). We describe here an interesting case suffering a persistent dystonia-parkinsonism syndrome(DPS) with motor tics, which expands the clinical phenotype ofNR4A2-associated DPS

Análisis de daño cromosomico espontáneo e inducido por mutágenos químicos en linfocitos de sangre periférica de personal aeronáutico de flota internacional

Se analizó el daño citogenético en linfocitos de sangre periférica de personal aeronáutico de flota internacional de la Argentina con el fin de evaluar los efectos de la radiación cósmica sobre el material genético de dicho grupo de individuos y determinar su sensibilidad a mutágenos químicos, como una primera aproxima­ción a determinar riesgo de cáncer en dicha población. Mediante técnicas citogenéticas convencionales, se determinó la frecuencia de aberraciones cromosómicas (AC) “espontáneas” e inducidas in vitro por bleomicina (BLM) en las etapas G0 y G2 del ciclo celular y de intercambios de cromátidas hermanas (ICH) espon­táneos e inducidos por estreptonigrina (EN) en linfocitos de sangre periférica de 21 tripulantes de flota inter­nacional (pilotos y azafatas) y 18 individuos controles. El personal aeronáutico presentó una frecuencia 3,5 veces mayor de AC “espontáneas” y 2 veces mayor de AC inducidas por BLM en la etapa G0 del ciclo celu­lar que los individuos de la población control. Estos resultados permiten sugerir que el personal aeronáutico de flota internacional de nuestro país debería ser considerado “grupo laboralmente expuesto a la radiación” y que el ensayo de BLM G0 sería el más apropiado para determinar sensibilidad a mutágenos en personal aeronáutico de flota internacional.Universidad Nacional de La Plat