Proposed observations of gravity waves from the early Universe via "Millikan oil drops"

Pairs of Planck-mass drops of superfluid helium coated by electrons (i.e., ``Millikan oil drops''), when levitated in a superconducting magnetic trap, can be efficient quantum transducers between electromagnetic (EM) and gravitational (GR) radiation. This leads to the possibility of a Hertz-like experiment, in which EM waves are converted at the source into GR waves, and then back-converted at the receiver from GR waves back into EM waves. Detection of the gravity-wave analog of the cosmic microwave background using these drops can discriminate between various theories of the early Universe.Comment: 10 pages, 2 figures, NASA "Quantum-to-Cosmos" conference proceedings to be published in IJMP

CloudMe forensics : a case of big-data investigation

The significant increase in the volume, variety and velocity of data complicates cloud forensic efforts, as such big data will, at some point, become computationally expensive to be fully extracted and analyzed in a timely manner. Thus, it is important for a digital forensic practitioner to have a well-rounded knowledge about the most relevant data artefacts that could be forensically recovered from the cloud product under investigation. In this paper, CloudMe, a popular cloud storage service, is studied. The types and locations of the artefacts relating to the installation and uninstallation of the client application, logging in and out, and file synchronization events from the computer desktop and mobile clients are described. Findings from this research will pave the way towards the development of tools and techniques (e.g. data mining techniques) for cloud-enabled big data endpoint forensics investigation

Using Abrupt Changes in Magnetic Susceptibility within Type-II Superconductors to Explore Global Decoherence Phenomena

A phenomenon of a periodic staircase of macroscopic jumps in the admitted magnetic field has been observed, as the magnitude of an externally applied magnetic field is smoothly increased or decreased upon a superconducting (SC) loop of type II niobium-titanium wire which is coated with a non-superconducting layer of copper. Large temperature spikes were observed to occur simultaneously with the jumps, suggesting brief transitions to the normal state, caused by en masse motions of Abrikosov vortices. An experiment that exploits this phenomenon to explore the global decoherence of a large superconducting system will be discussed, and preliminary data will be presented. Though further experimentation is required to determine the actual decoherence rate across the superconducting system, multiple classical processes are ruled out, suggesting that jumps in magnetic flux are fully quantum mechanical processes which may correspond to large group velocities within the global Cooper pair wavefunction.Comment: 13 pages, 4 figures, part of proceedings for FQMT 2011 conference in Prague, Czech Republi

Pressure dependence of the spin dynamics around a quantum critical point : An inelastic neutron scattering study of Ce0.87La0.13Ru2Si2

Inelastic neutron scattering experiments performed on a single crystal of the antiferromagnetic compound Ce$_{0.87}$La$_{0.13}$Ru$_{2}$Si$_{2}$ under applied pressures of up to 5 kbar are reported. A quantum critical point is reached at around 2.6 kbar where long-range magnetic order disappears. The variation of the characteristic energy scales with respect to temperature and pressure is followed and found to saturate in the ordered phase.Comment: 14 pages (6 figures

Modification des récepteurs cholinergiques de type nicotinique par des doses sublétales d'imidaclopride chez la blatte Periplaneta americana

Les insecticides néonicotinoïdes sont une classe d\u27insecticides utilisée pour contrôler les insectes ravageurs de cultures. Ces molécules miment l\u27effet de l\u27acétylcholine (ACh) en agissant comme des agonistes des récepteurs cholinergiques de type nicotinique (nAChRs) au niveau du système nerveux central des insectes. Suite à l\u27utilisation des néonicotinoïdes ces dernières années, des phénomènes de résistance ont été révélés chez beaucoup d\u27espèces. Ces phénomènes menacent d\u27une part l\u27agriculture et d\u27autre part la santé publique. Afin de comprendre les facteurs impliqués dans les phénomènes de résistance aux néonicotinoïdes, nous avons étudié les mécanismes d\u27adaptation développés suite à une exposition chronique à des doses sublétales de néonicotinoïde. Dans un premier temps, nous avons étudié la toxicité d\u27une molécule néonicotinoïde (l\u27imidaclopride) chez la blatte Periplaneta americana . Ensuite, l\u27effet d\u27une exposition chronique à une dose sublétale d\u27imidaclopride a été exploré sur neurones DUM (Dorsal Unpaired Median) de la blatte grâce à la technique électrophysiologique de patch - clamp, dans des conditions de potentiel imposé. Les premiers résultats obtenus montrent que cette exposition chronique peut modifier le profil pharmacologique des nAChRs au niveau des neurones DUM. En effet, une diminution de la sensibilité à l\u27imidaclopride des nAChRs a été mise en évidence. Dans un deuxième temps, nous avons montré en PCR quantitative que la diminution de la sensibilité des nAChRs pourrait avoir un lien avec une modification du niveau d\u27expression des différentes sous – unités qui composent ces récepteurs

Inelastic neutron scattering studies of the quantum frustrated magnet clinoatacamite, γ\gamma-Cu2(OD)3Cl, a proposed valence bond solid (VBS)

The frustrated magnet clinoatacamite, $\gamma$-Cu$_2$(OH)$_3$Cl, is attracting a lot of interest after suggestions that at low temperature it forms an exotic quantum state termed a Valence Bond Solid (VBS) made from dimerised Cu$^{2+}$ ($S=1/2$) spins.\cite{Lee_clinoatacamite} Key to the arguments surrounding this proposal were suggestions that the kagom\'e planes in the magnetic pyrochlore lattice of clinoatacamite are only weakly coupled, causing the system to behave as a quasi-2-dimensional magnet. This was reasoned from the near 95$^\circ$ angles made at the bridging oxygens that mediate exchange between the Cu ions that link the kagom\'e planes. Recent work pointed out that this exchange model is inappropriate for $\gamma$-Cu$_2$(OH)$_3$Cl, where the oxygen is present as a $\mu_3$-OH.\cite{Wills_JPC} Further, it used symmetry calculations and neutron powder diffraction to show that the low temperature magnetic structure ($T<6$ K) was canted and involved significant spin ordering on all the Cu$^{2+}$ spins, which is incompatible with the interpretation of simultaneous VBS and N\'eel ordering. Correspondingly, clinoatacamite is best considered a distorted pyrochlore magnet. In this report we show detailed inelastic neutron scattering spectra and revisit the responses of this frustrated quantum magnet.Comment: Proceedings of The International Conference on Highly Frustrated Magnetism 2008 (HFM2008