Dictyostelium discoideum slugs migrating in the absence of external stimuli tend to continue migrating in the original randomly 'chosen' direction. Spontaneous deviations from the starting direction accumulate with time at a rate that measures the 'physiological noise' in the slugs' steering mechanism. Most of the spontaneous turning signals arise in the transduction chain 'downstream' of the c...

This paper seeks to detect hot and cold IPO cycles in the Tunisian share market using a Markov regime switching model. Using a set of IPO activity measures (number of IPOs, level of underpricing, market conditions and duration), we establish a model which estimates these activity measures in hot and cold periods respectively. We depict the turning points from 1998 to 2012 for each activity meas...

We investigate the acousto-plasmonic dynamics of metallic nano-objects by means of resonant Raman scattering and time-resolved femtosecond transient absorption. We observe an unexpectedly strong acoustic vibration band in the Raman scattering of silver nanocolumns, usually not found in isolated nano-objects. The frequency and the polarization of this unexpected Raman band allow us to assign it ...

At the beginning of their offshore migration, hatchling sea turtles enter the ocean at night and establish a course away from land by swimming directly into oceanic waves. How turtles can detect wave direction while swimming under water in darkness, however, has not been explained. Objects in a water column beneath the surface of the ocean describe a circular movement as waves pass above. In pr...

Although titanium alloys have outstanding mechanical properties such as high hot hardness, a good strength-to-weight ratio and high corrosion resistance; their low thermal conductivity, high chemical affinity to tool materials severely impair their machinability. Ultrasonically assisted machining (UAM) is an advanced machining technique, which has been shown to improve machinability of a β-tita...