Precursory worldwide signatures of earthquake occurrences on Swarm satellite data.

The study of the preparation phase of large earthquakes is essential to understand the physical processes involved, and potentially useful also to develop a future reliable short-term warning system. Here we analyse electron density and magnetic field data measured by Swarm three-satellite constellation for 4.7 years, to look for possible in-situ ionospheric precursors of large earthquakes to study the interactions between the lithosphere and the above atmosphere and ionosphere, in what is called the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC). We define these anomalies statistically in the whole space-time interval of interest and use a Worldwide Statistical Correlation (WSC) analysis through a superposed epoch approach to study the possible relation with the earthquakes. We find some clear concentrations of electron density and magnetic anomalies from more than two months to some days before the earthquake occurrences. Such anomaly clustering is, in general, statistically significant with respect to homogeneous random simulations, supporting a LAIC during the preparation phase of earthquakes. By investigating different earthquake magnitude ranges, not only do we confirm the well-known Rikitake empirical law between ionospheric anomaly precursor time and earthquake magnitude, but we also give more reliability to the seismic source origin for many of the identified anomalies.

[Echocardiographic calculation of left ventricle ejection volume. 1) Preliminary note: comparison of diverse formula]. / Calcolo ecocardiografico del volume di eiezione ventricolare sinistro. 1) Nota preliminare: confronto fra diverse formule.

Four different formulae to calculate left ventricular ejection volume were examined in the present study. Formulae show a different degree of reliability and, however, their use prove to be limited if heart rate factor is not considered. These results emphasized the great importance of determining left ventricular ejection volume in terms of cardiac output.

[Echocardiographic calculation of left ventricle ejection volume. 2) Proposal of a new equation]. / Calcolo ecocardiografico del volume di eiezione ventricolare sinistro. 2) Proposta di una nuova equazione.

A new formula is proposed to calculate left ventricular ejection volume. It has been originated directly from Yeh equation, introducing two important factors: 1) left ventricular and diastolic diameter 2) ejection time adjusted according to heart rate. This new formula prove to give satisfactory results both as to stroke volume and cardiac output, thus allowing its possible clinical application.