Effect of cosmic rays on the resonant gravitational wave detector at temperature T=1.5 K

The interaction between cosmic rays and the gravitational wave bar detector is experimentally studied with the aluminum bar at temperature of T=1.5 K. The results are compared with those obtained in the previous runs when the bar was at T=0.14 K. The results of the run at T=1.5 K are in agreement with the thermo-acoustic model; no large signals at unexpected rate are noticed, unlike the data taken in the run at T=0.14 K. The observations suggest a larger efficiency in the mechanism of conversion of the particle energy into vibrational mode energy when the aluminum bar is in the superconductive status.     

Probabilistic time and the quantum gravity interpretation

We analyze the perturbed minisuperspace models of quantum gravity through the analogy with the time-independent Schrödinger equation. We show that a time variable defined in a previous work, the probabilistic time, is the variable which yields the backreaction Einstein equations.     

Optimization of lipospheres production by factorial design and their performances on a dielectrophoretic lab-on-a-chip platform

Aim of this study was to investigate the effect of the preparation parameters on the characteristics of lipospheres that would optimally fit to a lab-on-a-chip platform. Lipospheres were produced by melt dispersion technique using different lipid mixture heated to 70 °C and then emulsified into an external aqueous phase. The initial part of the work was devoted to the selection of the best lipid composition by a classical intuitive approach while the optimization and the screening of the experimental parameters were conducted through a “design of experiments”. Once the best preparation parameters were selected, they were adopted also for the production of cationic lipospheres (CLS). The second part of the study describes the analysis of the lipospheres performances when applied to a DEParray™Chip. The loading, distribution, movement and separation of neutral and cationic lipospheres were investigated. The obtained data show that both neutral and cationic lipospheres can be efficiently used in association with DEParray™Chip.     

An improved proximity force approximation for electrostatics

A quite straightforward approximation for the electrostatic interaction between two perfectly conducting surfaces suggests itself when the distance between them is much smaller than the characteristic lengths associated with their shapes. Indeed, in the so called “proximity force approximation” the electrostatic force is evaluated by first dividing each surface into a set of small flat patches, and then adding up the forces due two opposite pairs, the contributions of which are approximated as due to pairs of parallel planes. This approximation has been widely and successfully applied in different contexts, ranging from nuclear physics to Casimir effect calculations. We present here an improvement on this approximation, based on a derivative expansion for the electrostatic energy contained between the surfaces. The results obtained could be useful for discussing the geometric dependence of the electrostatic force, and also as a convenient benchmark for numerical analyses of the tip–sample electrostatic interaction in atomic force microscopes.