Isolation of avian influenza virus (H9N2) from emu in China

This is the first reported isolation of avian influenza virus (AIV) from emu in China. An outbreak of AIV infection occurred at an emu farm that housed 40 four-month-old birds. Various degrees of haemorrhage were discovered in the tissues of affected emus. Cell degeneration and necrosis were observed microscopically. Electron microscopy revealed round or oval virions with a diameter of 80 nm to 120 nm, surrounded by an envelope with spikes. The virus was classified as low pathogenic AIV (LPAIV), according to OIE standards. It was named A/Emu/HeNen/14/2004(H9N2)(Emu/HN/2004). The HA gene (1683bp) was amplified by RT-PCR and it was compared with other animal H9N2 AIV sequences in GenBank, the US National Institutes of Health genetic sequence database. The results suggested that Emu/HN/2004 may have come from an avian influenza virus (H9N2) from Southern China

A telephone survey of parental attitudes and behaviours regarding teenage drinking

<p>Abstract</p> <p>Background</p> <p>Irish teenagers demonstrate high rates of drunkenness and there has been a progressive fall in age of first drinking in recent decades. International research indicates that parents exert substantial influence over their teenager's drinking. We sought to determine the attitudes and behaviours of Irish parents towards drinking by their adolescent children.</p> <p>Methods</p> <p>We conducted a telephone survey of a representative sample of of 234 parents who had a teenager aged between 13 and 17 years.</p> <p>Results</p> <p>Six per cent reported that they would be unconcerned if their son or daughter was to binge drink once per month. On the issue of introducing children to alcohol in the home, 27% viewed this as a good idea while 63% disagreed with this practice. Eleven per cent of parents reported that they had given a drink to their teenager at home. Parents who drank regularly themselves, who were from higher socio-demographic groups and who lived in the east of Ireland demonstrated more permissive attitudes to teenage drinking.</p> <p>Conclusions</p> <p>We found no evidence of widespread permissive attitudes and behaviours among Irish parents. Given that parental influences have been demonstrated to exert substantial impact on teenage drinking, it may be possible to harness the concerns of Irish parents more effectively to reverse the trends of escalating alcohol related harm in Ireland.</p

Monotone and near-monotone biochemical networks

Monotone subsystems have appealing properties as components of larger networks, since they exhibit robust dynamical stability and predictability of responses to perturbations. This suggests that natural biological systems may have evolved to be, if not monotone, at least close to monotone in the sense of being decomposable into a “small” number of monotone components, In addition, recent research has shown that much insight can be attained from decomposing networks into monotone subsystems and the analysis of the resulting interconnections using tools from control theory. This paper provides an expository introduction to monotone systems and their interconnections, describing the basic concepts and some of the main mathematical results in a largely informal fashion

Hepatitis C Virus infection in Irish drug users and prisoners : a scoping review

Background: Hepatitis C infection is a major public health concern globally. In Ireland, like other European countries, people who use drugs (PWUD) and prisoners carry a larger HCV disease burden than the general population. Recent advances in HCV management have made HCV elimination across Europe a realistic goal. Engaging these two marginalised and underserved populations remains a challenge. The aim of this review was to map key findings and identify gaps in the literature (published and unpublished) on HCV infection in Irish PWUD and prisoners.Methods: A scoping review guided by the methodological framework set out by Levac and colleagues (based on previous work by Arksey & O’Malley).Results: A total of 58 studies were identified and divided into the following categories; Epidemiology, Guidelines and Policy, Treatment Outcomes, HCV -related Health Issues and qualitative research reporting on Patients’ and Health Providers’ Experiences. This review identified significantly higher rates of HCV infection among Irish prisoners and PWUD than the general population. There are high levels of undiagnosed and untreated HCV infection in both groups. There is poor engagement by Irish PWUD with HCV services and barriers have been identified. Prison hepatology nurse services have a positive impact on treatment uptake and outcomes. Identified gaps in the literature include; lack of accurate epidemiological data on incident infection, untreated chronic HCV infection particularly in PWUD living outside Dublin and those not engaged with OST. Conclusion: Ireland like other European countries has high levels of undiagnosed and untreated HCV infection. Collecting, synthesising and identifying gaps in the available literature is timely and will inform national HCV screening, treatment and prevention strategies

Switching on a two-dimensional time-harmonic scalar wave in the presence of a diffracting edge

This paper concerns the switching on of two-dimensional time-harmonic scalar waves. We first review the switch-on problem for a point source in free space, then proceed to analyse the analogous problem for the diffraction of a plane wave by a half-line (the 'Sommerfeld problem'), determining in both cases the conditions under which the field is well-approximated by the solution of the corresponding frequency domain problem. In both cases the rate of convergence to the frequency domain solution is found to be dependent on the strength of the singularity on the leading wavefront. In the case of plane wave diffraction at grazing incidence the frequency domain solution is immediately attained along the shadow boundary after the arrival of the leading wavefront. The case of non-grazing incidence is also considered. © 2010 Elsevier B.V

ASYMPTOTIC ANALYSIS OF A BUCKLING PROBLEM FOR AN EMBEDDED SPHERICAL SHELL

The axisymmetric buckling of a spherical shell embedded in an elastic medium with uniaxial compression at infinity is examined in the limit of small shell thickness ratio. An asymptotic method is developed by considering the paradigm problem of a beam attached to a Winkler substrate of variable stiffness, which in the small aspect ratio limit displays the same behavior as the shell. The asymptotic method is then applied to the Euler-Lagrange equations corresponding to shell buckling. The system is analyzed in two distinguished limits, displaying good agreement with the full numerical results. © 2009 Society for Industrial and Applied Mathematics

Theoretical exploration of blastocyst morphogenesis.

A theoretical exploration of cell distribution on the mouse blastocyst is conducted. A model ball of cells represents the morula which develops into a 32-cell model blastocyst that is enclosed in a spherical surface with a hemispherical cavity at one end. In the combinatorial analysis it is assumed that each cell of the 2-cell embryo forms 16 cells in the blastocyst and that these 16 cells touch each other. The results of the analysis identify a tendency for one set of 16 cells to contribute twice as many cells to the basal solid end of the blastocyst than the other set, a developmental bias that is also found by some observers of natural blastocysts. In the geometric analysis, half the volume of the inner group of cells of the morula and blastocyst and half the volume of the surrounding shell cells, the trophectoderm, is assumed to be formed from the progeny of each 2-cell stage cell. Making various assumptions about morphogenesis, it is found that there is a tendency for a curved frontier between the volumes from each 2-cell stage cell, the clonal volumes, to lie at an angle of 43.4 degrees to the equator of the blastocyst and for the bulk of the frontier circumference to lie on either side of the equator. These tendencies are also found by some observers of real blastocysts

One-dimensional wave dispersion in layered media

Homogenisation theory reveals that long one-dimensional waves propagating in a medium with spatially periodic wave speed can behave like dispersive waves in an appropriately homogenised medium. However the precise time and length scales over which this dispersive behaviour is a good approximation are not clear. This paper describes what happens in a specific case when the sound speed and initial conditions allow the problem to be reduced to a finite system of difference equations which can be solved exactly. The long-time asymptotics are compared with the predictions of homogenisation theory and new light is shed on the dispersion phenomeno