Is there a structural break in equilibrium velocity in the euro area?

We investigate the stability of M3 income velocity in the euro area. We apply a set of breakpoint procedures to examine this issue and conclude that at least one structural change occurred around 2000-2001. We also find evidence of another structural break around 1992-1993. These two breaks seem to affect both the level and the slope of the income velocity of M3. We then estimate a model of equilibrium velocity that factors in the opportunity cost of M3, along the lines suggested by Orphanides and Porter (2000). Here again, we find some evidence of instability in equilibrium velocity. Given the importance of the assumption of stable velocity trends for both the derivation of the reference value and the two-pillar strategy of the Eurosystem, these findings question the relevance of some excess liquidity indicators directly computed from the reference value and may call for some adjustments in the conduct of the ECB's monetary policy.M3 velocity ; Breakpoint tests; ECB.

A biologically inspired network design model

A network design problem is to select a subset of links in a transport network that satisfy passengers or cargo transportation demands while minimizing the overall costs of the transportation. We propose a mathematical model of the foraging behaviour of slime mould P. polycephalum to solve the network design problem and construct optimal transport networks. In our algorithm, a traffic flow between any two cities is estimated using a gravity model. The flow is imitated by the model of the slime mould. The algorithm model converges to a steady state, which represents a solution of the problem. We validate our approach on examples of major transport networks in Mexico and China. By comparing networks developed in our approach with the man-made highways, networks developed by the slime mould, and a cellular automata model inspired by slime mould, we demonstrate the flexibility and efficiency of our approach

Persisting Mixed Cryoglobulinemia in Chikungunya Infection

Chikungunya virus is present in tropical Africa and Asia and is transmitted by mosquito bites. The disease is characterized by fever, headache, severe joint pain and transient skin rash for about a week. Most patients experience persisting joint pain and/or stiffness for months to years. In routine practice, diagnosis is based upon serology. Since 2004 there has been an ongoing giant outbreak of Chikungunya fever in East Africa, the Indian Ocean Islands, India and East Asia. In parallel, more than 1,000 travelers were diagnosed with imported Chikungunya infection in most developed countries. Considering the clinical features of our patients (joint pain), we hypothesized that cryoglobulins could be involved in the pathophysiology of the disease as observed in chronic hepatitis C infection. Cryoglobulins, which are immunoglobulins that precipitate when temperature is below 37°C, can induce rheumatic and vascular disorders. From April 2005 through May 2007, we screened all patients with possible imported Chikungunya infection for cryoglobulins. They were present in over 90% of patients, and possibly responsible for the unexpected false negativity of serological assays. Cryoglobulin frequency and levels decreased with time in recovering patients

An evaluation of the performance of P"* as an indicator of monetary policy A cointegration approach applied to France and Germany

SIGLEAvailable from British Library Document Supply Centre- DSC:9104.31185(BU-IFGWP--92-06) / BLDSC - British Library Document Supply CentreGBUnited Kingdo