The fluctuations, under time reversal, of the natural time and the entropy distinguish similar looking electric signals of different dynamics

We show that the scale dependence of the fluctuations of the natural time itself under time reversal provides a useful tool for the discrimination of seismic electric signals (critical dynamics) from noises emitted from man made sources as well as for the determination of the scaling exponent. We present recent data of electric signals detected at the Earth's surface, which confirm that the value of the entropy in natural time as well as its value under time reversal are smaller than that of the entropy of a "uniform" distribution.Comment: 29 pages including 24 figure and 1 Tabl

Comment on "Effects of Thickness on the Spin Susceptibility of the Two Dimensional Electron Gas"

A comment on a recent paper (PRL {\bf 94}, 226405 (2005)) by S. De Palo, M. Botti, S. Moroni, and Gaetano Senatore

BlogForever D3.2: Interoperability Prospects

This report evaluates the interoperability prospects of the BlogForever platform. Therefore, existing interoperability models are reviewed, a Delphi study to identify crucial aspects for the interoperability of web archives and digital libraries is conducted, technical interoperability standards and protocols are reviewed regarding their relevance for BlogForever, a simple approach to consider interoperability in specific usage scenarios is proposed, and a tangible approach to develop a succession plan that would allow a reliable transfer of content from the current digital archive to other digital repositories is presented

Report on the development of the national method for the assessment of ecological status of natural lakes in Greece, with the use of littoral benthic invertebrates

This report discusses the development of a national method for the assessment of ecological status of natural lakes in Greece, based on the Biological Quality Element (BQE) “Benthic Invertabrate Fauna” from the littoral zone, the Hellenic assessment method for Lake Littoral Benthic invertebrate fauna (HeLLBI). Most lake assessment methods based on benthic macroinvertebrates to date, evaluate eutrophication and acidification; fewer methods assess morphological pressures on lake ecosystems and they are mostly based on benthic macroinvertebrates from the littoral zone (Poikane et al., 2016). Greece has a national method for zoobenthos from the profundal zone (GLBiI - Greek Lake Benthic invertebrate Index), that addresses eutrophication, which is included in the 2018 Intercalibration Decision [Commission Decision (EU) 2018/229] (Ntislidou et al., 2018). The development of the current assessment method, as described in this report, is based on data from the national water monitoring network. In particular, 109 littoral sampling sites in 21 lakes (29 lake years) have been surveyed for benthic invertebrates during the 2015-2018 sampling campaign. Natural lakes in Greece are grouped into 3 types, according to the mixing regime and depth gradient1. As the sampling took place in the littoral zone, data from all lake types were pooled in the dataset. The HeLLBI method consists of metrics indicative of taxonomic composition and abundance, sensitivity/tolerance of taxa and taxa diversity. It addresses morphological alteration and eutrophication pressures

Identifying the occurrence time of an impending mainshock: A very recent case

The procedure by means of which the occurrence time of an impending mainshock can be identified by analyzing in natural time the seismicity in the candidate area subsequent to the recording of a precursory Seismic Electric Signals (SES) activity is reviewed. Here, we report the application of this procedure to an Mw5.4 mainshock that occurred in Greece on 17 November 2014 and was strongly felt in Athens. This mainshock (which is pretty rare since it is the strongest in that area for more than half a century) was preceded by an SES activity recorded on 27 July 2014 and the results of the natural time analysis reveal that the system approached the critical point (mainshock occurrence) early in the morning on 15 November 2014. Similar SES activities that have been recently recorded are also presented. Furthermore, in a Note we discuss the case of the Mw5.3 earthquake that was also strongly felt in Athens on 19 July 2019.Comment: An early version of this paper appeared in Earthq. Sci. 28 (2015) 215-222 [doi:10.1007/s11589-015-0122-3], whereas in the present version new data collected during 2019 and 2020 have been added. 8 pages, 11 figure

Natural entropy fluctuations discriminate similar looking electric signals emitted from systems of different dynamics

Complexity measures are introduced, that quantify the change of the natural entropy fluctuations at different length scales in time-series emitted from systems operating far from equilibrium. They identify impending sudden cardiac death (SD) by analyzing fifteen minutes electrocardiograms, and comparing to those of truly healthy humans (H). These measures seem to be complementary to the ones suggested recently [Phys. Rev. E {\bf 70}, 011106 (2004)] and altogether enable the classification of individuals into three categories: H, heart disease patients and SD. All the SD individuals, who exhibit critical dynamics, result in a common behavior.Comment: Published in Physical Review