Proceedings of the Workshop on Calculation of Double-Beta-Decay Matrix Elements (MEDEX'01), Prague, Czech Republic, July 11-15, 2001

Table of Contents

Proceedings of the Workshop on Calculation of Double-Beta-Decay Matrix Elements (MEDEX'01), Prague, Czech Republic, July 11-15, 2001     

Fluctuation analysis of the time dynamics of laser distance data measured in the medieval Jeroným Mine (Czech Republic)

Fractal tools are used to investigate the hourly time fluctuations of the ceiling height of a chamber located in the medieval Jeroným Mine, which is one of the Cultural National Heritage sites of the Czech Republic. The data were measured from 2008 to 2010 by a laser distance meter (Leica DISTO^TMA4). The scaling behavior is revealed by means of different statistics: the power spectrum method, the detrended fluctuation analysis, the Higuchi analysis and the mean distance spanned within time L. The values of the scaling exponents estimated by means of these methods indicate that the temporal fluctuations of the ceiling height are not typical of a purely random stochastic process (i.e. white noise), but evidence the presence of long-range correlations. Furthermore, it is found that these correlations are linear.     

Specific features of ionospheric total electron content variations in the periods of preparation of the earthquakes on March 11, 2011 (Japan) and October 23, 2011 (Turkey)

The main morphological features of variations of the total electron content (TEC) of the ionosphere before the earthquakes on March 11, 2011 (Japan) and October 23, 2011 (Turkey) are examined. The revealed features are compared to those of ionospheric TEC disturbances observed prior to several other large seismic events, as well as to those included in a list of the most frequently observed ionospheric TEC disturbances interpreted as possible ionospheric precursors of earthquakes. It is shown that, in the periods of preparation of the earthquakes under consideration, on March 8–11 and October 20–23, abnormal ionospheric TEC disturbances were observed as long-lived structures in a near-epicentral region and in the region magnetically conjugated to it.     

Answer to the comments made by N. Gibson,H. Rauscher and G. Roebben on the article by A.J. Lecloux (J Nanopart Res (2015) 17:447) regarding the use of the volume-specific surface area (VSSA) to classify nanomaterials

This article is an answer to the comments made by N. Gibson, H. Rauscher and G. Roebben on the article by Lecloux (J Nanopart Res 17:447, 2015) regarding the use of the volume-specific surface area (VSSA) to classify nanomaterials. The key point of discussion is the comparison of two models. The VSSA concept, developed for monodispersed spherical non-porous particle size distribution, was applied in two different ways to calculate the VSSA corresponding to a poly-dispersed distribution of particle size: on one side, a total VSSA value that is the number-weighted sum of the individual VSSAs corresponding to each particle size present with its frequency in the distribution. On the other side, a weight-averaged VSSA based on the measurement method, dividing the total surface area of all the particles by their total volume. The key questions are which model is better representing the experimental VSSA values obtained by analysis of the nitrogen adsorption isotherms and which model is the most appropriate to identify nanomaterials? This cannot be answered on a theoretical basis. Only a comparison with various experimental data could decide which model is the most appropriate.     

Statistical and Criticality Analysis of the Lower Ionosphere Prior to the 30 October 2020 Samos (Greece) Earthquake (M6.9), Based on VLF Electromagnetic Propagation Data as Recorded by a New VLF/LF Receiver Installed in Athens (Greece)

In this work we present the statistical and criticality analysis of the very low frequency (VLF) sub-ionospheric propagation data recorded by a VLF/LF radio receiver which has recently been established at the University of West Attica in Athens (Greece). We investigate a very recent, strong (M6.9), and shallow earthquake (EQ) that occurred on 30 October 2020, very close to the northern coast of the island of Samos (Greece). We focus on the reception data from two VLF transmitters, located in Turkey and Israel, on the basis that the EQ’s epicenter was located within or very close to the 5th Fresnel zone, respectively, of the corresponding sub-ionospheric propagation path. Firstly, we employed in our study the conventional analyses known as the nighttime fluctuation method (NFM) and the terminator time method (TTM), aiming to reveal any statistical anomalies prior to the EQ’s occurrence. These analyses revealed statistical anomalies in the studied sub-ionospheric propagation paths within ~2 weeks and a few days before the EQ’s occurrence. Secondly, we performed criticality analysis using two well-established complex systems’ time series analysis methods—the natural time (NT) analysis method, and the method of critical fluctuations (MCF). The NT analysis method was applied to the VLF propagation quantities of the NFM, revealing criticality indications over a period of ~2 weeks prior to the Samos EQ, whereas MCF was applied to the raw receiver amplitude data, uncovering the time excerpts of the analyzed time series that present criticality which were closest before the Samos EQ. Interestingly, power-law indications were also found shortly after the EQ’s occurrence. However, it is shown that these do not correspond to criticality related to EQ preparation processes. Finally, it is noted that no other complex space-sourced or geophysical phenomenon that could disturb the lower ionosphere did occur during the studied time period or close after, corroborating the view that our results prior to the Samos EQ are likely related to this mainshock.     

Proximity of the layered organic conductors alpha-(BEDT-TTF)2MHg(SCN)4 (M = K,NH4) to a charge-ordering transition

While the optical properties of the superconducting salt alpha-(BEDT-TTF)(2)-NH4Hg(SCN)(4) remain metallic down to 2 K, in the nonsuperconducting K analog a pseudogap develops at frequencies of about 200 cm(-1) for temperatures T<200 K. We show that the optical conductivity calculated with exact-diagonalization techniques on an extended Hubbard model at quarter filling is consistent with the observed low-frequency feature. We argue that the different optical responses observed are a consequence of the proximity of these compounds to a charge-ordering transition driven by the intermolecular Coulomb repulsion.