Apparatus for disintegrating kidney stones

The useful life of the wire probe in an ultrasonic kidney stone disintegration instrument is enhanced and prolonged by attaching the wire of the wire probe to the tip of an ultrasonic transducer by means of a clamping arrangement. Additionally, damping material is applied to the wire probe in the form of a damper tube through which the wire probe passes in the region adjacent the transducer tip. The damper tube extends outwardly from the transducer tip a predetermined distance, terminating in a resilient soft rubber joint. Also, the damper tube is supported intermediate its length by a support member. The damper system thus acts to inhibit lateral vibrations of the wire in the region of the transducer tip while providing little or no damping to the linear vibrations imparted to the wire by the transducer

Motives for parental money transfers in Europe.

We find a high prevalence of Europeans giving equal financial transfers to their adult children, regardless of siblings’ income differences. This behaviour is sharply different from previously documented for American counterparts and it is not predicted by any conventional model on family transfers. We build a model to explain the motives for European parental transfers which includes concern with fairness and leaves altruism as an additional motive. We show that, in contrast to the prediction of the pure altruism model, parents do not offset income inequality among their children but decide to give equal transfers in order to be “fair”. However, the parents might start to give larger transfers to poorer children if the siblings’ income inequality becomes unbearable from the parent’s view. We find evidence for this behaviour using simulations for parameter’s distributions and also microeconomic data of 9 European countries from the Survey of Health, Aging, and Retirement in Europe (SHARE).

The structure of Deitmar Schemes, II. Zeta functions and automorphism groups

We provide a coherent overview of a number of recent results obtained by the authors in the theory of schemes defined over the field with one element. Essentially, this theory encompasses the study of a functor which maps certain geometries including graphs to Deitmar schemes with additional structure, as such introducing a new zeta function for graphs. The functor is then used to determine automorphism groups of the Deitmar schemes and base extensions to fields.Comment: 8 page

Stochastic mean field formulation of the dynamics of diluted neural networks

We consider pulse-coupled Leaky Integrate-and-Fire neural networks with randomly distributed synaptic couplings. This random dilution induces fluctuations in the evolution of the macroscopic variables and deterministic chaos at the microscopic level. Our main aim is to mimic the effect of the dilution as a noise source acting on the dynamics of a globally coupled non-chaotic system. Indeed, the evolution of a diluted neural network can be well approximated as a fully pulse coupled network, where each neuron is driven by a mean synaptic current plus additive noise. These terms represent the average and the fluctuations of the synaptic currents acting on the single neurons in the diluted system. The main microscopic and macroscopic dynamical features can be retrieved with this stochastic approximation. Furthermore, the microscopic stability of the diluted network can be also reproduced, as demonstrated from the almost coincidence of the measured Lyapunov exponents in the deterministic and stochastic cases for an ample range of system sizes. Our results strongly suggest that the fluctuations in the synaptic currents are responsible for the emergence of chaos in this class of pulse coupled networks.Comment: 12 Pages, 4 Figure