Magnetic Fluctuations and Turbulence in the Venus Magnetosheath and Wake

Recent research has shown that distinct physical regions in the Venusian induced magnetosphere are recognizable from the variations of strength and of wave/fluctuation activity of the magnetic field. In this paper the statistical properties of magnetic fluctuations are investigated in the Venusian magnetosheath, terminator, and wake regions. The latter two regions were not visited by previous missions. We found 1/f fluctuations in the magnetosheath, large-scale structures near the terminator and more developed turbulence further downstream in the wake. Location independent short-tailed non-Gaussian statistics was observed.Comment: 16 pages, 4 figure

On the entropy of plasmas described with regularized κ\kappa-distributions

In classical thermodynamics the entropy is an extensive quantity, i.e.\ the sum of the entropies of two subsystems in equilibrium with each other is equal to the entropy of the full system consisting of the two subsystems. The extensitivity of entropy has been questioned in the context of a theoretical foundation for the so-called $\kappa$-distributions, which describe plasma constituents with power-law velocity distributions. We demonstrate here, by employing the recently introduced {\it regularized $\kappa$-distributions}, that entropy can be defined as an extensive quantity even for such power-law-like distributions that truncate exponentially.Comment: Preprint accepted for publication in Phys. Rev.

Anatomical investigation of 4,000-years old cedrus libani wood remains from Egypt

The anatomical composition of the 4,000-years old Cedrus libaniremains from an archeological excavation is the same as the anatomical composition of xylem of recent Cedrus libani. The width of growth rings in the remains is narrow. The mean values are 0.82-1.78 mm. Within the growth ring, the early wood is wide and the late wood is fairly narrow. According to the growth ring widht series, as nowadays, too, unfavourable years alternated with more favourable ones. Length of tracheids were formed in the wider growth rings, and longer ones in the narrower. Within the length of tracheids increases from growth ring boundary to growth ring boundary.Frequencies of the length of tracheids within a growth ring show the Gaussian distribution. The tracheid cells end in normal tip. The cell wall thickness is thin (3.1 µm) in the early wood, and thick (9.6 µm) in the late wood. The cell lumen is wide in the early wood (44.3µm), and narrow in the late wood (23.8 µm)

Polyethylene imine-based receptor immobilization for label free bioassays

Polyethylene imine (PEI) based immobilization of antibodies is described and the concept is proved on the label free assay of C-Reactive Protein (CRP). This novel immobilization method is composed of a hyperbranched PEI layer which was deposited at a high pH (9.5) on the sensor surface. The free amino groups of PEI were derivatized with neutravidin by Biotin N-hydroxysuccinimide ester and the biotinylated anti-CRP antibody immobilized on this layer. Direct binding assay of recombinant CRP was successfully performed in the low μg/ml concentrations using a label free optical waveguide biosensor

Multi-scale magnetic field intermittence in the plasma sheet

This paper demonstrates that intermittent magnetic field fluctuations in the plasma sheet exhibit transitory, localized, and multi-scale features. We propose a multifractal based algorithm, which quantifies intermittence on the basis of the statistical distribution of the 'strength of burstiness', estimated within a sliding window. Interesting multi-scale phenomena observed by the Cluster spacecraft include large scale motion of the current sheet and bursty bulk flow associated turbulence, interpreted as a cross-scale coupling (CSC) process.Comment: 18 pages, 7 figure

Trapping Long-Lifetime Excitons in a Two-Dimensional Harmonic Potential

We report an important step forward for the goal of unambiguous observation of Bose-Einstein condensation of excitons in semiconductors. We have demonstrated a system in which excitons live for microseconds, much longer than their thermalization time, move over distances of hundreds of microns, and can be trapped in a harmonic potential exactly analous to the traps for atomic condensates. We also report recent results of a new method for observing evidence of Bose-Einstein condensation, by angular resolution of the emitted luminescence.Comment: Invited paper for International Conference on Spontaneous Coherence in Excitonic Systems, Seven Springs, PA, May 2004. To appear in Solid State Communication

Quantitative features of multifractal subtleties in time series

Based on the Multifractal Detrended Fluctuation Analysis (MFDFA) and on the Wavelet Transform Modulus Maxima (WTMM) methods we investigate the origin of multifractality in the time series. Series fluctuating according to a qGaussian distribution, both uncorrelated and correlated in time, are used. For the uncorrelated series at the border (q=5/3) between the Gaussian and the Levy basins of attraction asymptotically we find a phase-like transition between monofractal and bifractal characteristics. This indicates that these may solely be the specific nonlinear temporal correlations that organize the series into a genuine multifractal hierarchy. For analyzing various features of multifractality due to such correlations, we use the model series generated from the binomial cascade as well as empirical series. Then, within the temporal ranges of well developed power-law correlations we find a fast convergence in all multifractal measures. Besides of its practical significance this fact may reflect another manifestation of a conjectured q-generalized Central Limit Theorem