Abstract. Spina bifida was diagnosed in four English Bulldogs and one Collie dog. These cases and the examination of records from the Veterinary Medical Data Program suggested a high incidence of spina bifida in the English Bulldog. Urinary and fecal incontinence was the most common reason for initial examination for the five dogs. Radiographs and myelography confirmed the diagnosis of spina bifida. Blood, cerebrospinal fluid and urine analyses did not aid diagnosis but urocystitis was identified. In addition to spina bifida, clinical signs and morphologic changes in the spinal cords of all five dogs fulfilled the criteria for an additional diagnosis of spinal dysraphism. A common pathogenesis for the two conditions is suggested.

Electrostatic gating and optical pumping schemes enable efficient time modulation of graphene's free carrier density, or Drude weight. We develop a theory for plasmon propagation in graphene under temporal modulation. When the modulation is on the timescale of the plasmonic period, we show that it is possible to create a backwards-propagating or standing plasmon wave and to amplify plasmons. The theoretical models show very good agreement with direct Maxwell simulations.

No abstract