73 research outputs found
Scientific Review on the Ionospheric Absorption and Research Prospects of a Complex Eikonal Model for One-Layer Ionosphere
The present paper conducts a scientific review on ionospheric absorption, extrapolating the research prospects of a complex eikonal model for one-layer ionosphere. As regards the scientific review, here a quasi-longitudinal (QL) approximation for nondeviative absorption is deduced which is more refined than the corresponding equation reported by Davies (1990). As regards the research prospects, a complex eikonal model for one-layer ionosphere is analyzed in depth here, already discussed by Settimi et al. (2013). A simple formula is deduced for a simplified problem. A flat, layered ionospheric medium is considered, without any horizontal gradient. The authors prove that the QL nondeviative amplitude absorption according to the complex eikonal model is more accurate than Rawer's theory (1976) in the range of middle critical frequencies
L'individuazione di un benchmark per il fabbisogno di spesa dei comuni italiani: un'analisi per gruppi omogenei
The paper presents an estimate of the expenditure requirements to be used as a benchmark in the identification of best practices in the spending behavior of the municipalities. In order to distinguish the determinants of theoretical expenditure requirements with respect to those relating to current expenditure we use a two-stage procedure. The first stage includes the municipalities in homogeneous groups according to structural factors through clustering techniques; in the second stage we estimate current expenditure through variables that capture peculiar factors and preferences within groups identified at the first stage
Possible Lithosphere-Atmosphere-Ionosphere Coupling effects prior to the 2018 Mw = 7.5 Indonesia earthquake from seismic, atmospheric and ionospheric data
In this study, we analyse Lithosphere Atmosphere Ionosphere Coupling (LAIC) effects to identify some phenomena
that could, possibly, be linked to the preparation phase of the MW=7.5 earthquake occurred in
Indonesia on September 28th, 2018, by investigating the eight months preceding the seismic event.
First, we find a seismic acceleration that started two months before the mainshock. Then, studying some
physical properties of the atmosphere (skin temperature, total column water vapor and aerosol optical thickness),
we find two increases of atmospheric anomalies about 6 and 3.7 months before the mainshock, and the
latter one is very promising as a candidate for seismic-related phenomena. Furthermore, we investigate ionospheric
disturbances, by analysing the Swarm and, for the first time, China Seismo-Electromagnetic Satellite
(CSES), magnetic and electron density data during quiet geomagnetic time. From different techniques, we find
interesting anomalies concentrated around 2.7 months before the mainshock.
On August 19th, 2018, Swarm and CSES showed an enhancement of the electron density during night time.
We critically discuss the possibility that such phenomenon can be a possible pre-seismic-induced ionospheric
effect.
Finally, we performed a cumulative analysis using all detected anomalies, as a test case for a possible chain of
physical phenomena that could happen before the earthquake occurrence. With this study, we support the
usefulness to collect and store large Earth ground and satellite observational dataset that in the future could be
useful to monitor in real time the seismic zones to anticipate earthquakes, although nowadays, there is no
evidence about useful prediction capabilities.Published1040972A. Fisica dell'alta atmosferaJCR Journa
Clinical risk score to predict in-hospital mortality in COVID-19 patients: a retrospective cohort study
Magnetic Field and Electron Density Data Analysis from Swarm Satellites Searching for Ionospheric Effects by Great Earthquakes: 12 Case Studies from 2014 to 2016
We analyse Swarm satellite magnetic field and electron density data one month before and one month after 12 strong earthquakes that have occurred in the first 2.5 years of Swarm satellite mission lifetime in the Mediterranean region (magnitude M6.1+) or in the rest of the world (M6.7+). The search for anomalies was limited to the area centred at each earthquake epicentre and bounded by a circle that scales with magnitude according to the Dobrovolsky’s radius. We define the magnetic and electron density anomalies statistically in terms of specific thresholds with respect to the same statistical quantity along the whole residual satellite track (|geomagnetic latitude| ≤ 50°, quiet geomagnetic conditions). Once normalized by the analysed satellite tracks, the anomalies associated to all earthquakes resemble a linear dependence with earthquake magnitude, so supporting the statistical correlation with earthquakes and excluding a relationship by chance.PublishedID 3711A. Geomagnetismo e PaleomagnetismoJCR Journa
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.Publishedid 202872A. Fisica dell'alta atmosferaJCR Journa
Impact of alien insect pests on Sardinian landscape and culture
Geologically Sardinia is a raft which, for just under thirty million years, has been crossing the western Mediterranean, swaying like a pendulum from the Iberian to the Italian Peninsula. An island so large and distant from the other lands, except for its "sister" Corsica, has inevitably developed an autochthonous flora and fauna over such a long period of time. Organisms from other Mediterranean regions have added to this original contingent. These new arrivals were not randomly distributed over time but grouped into at least three great waves. The oldest two correspond with the Messinian salinity crisis about 7 million years ago and with the ice age, when, in both periods, Sardinia was linked to or near other lands due to a fall in sea level. The third, still in progress, is linked to human activity. Man has travelled since ancient times and for many centuries introduced allochthonous species to Sardinia which radically modified the native flora and fauna, but always at a very slow and almost unnoticeable rate. The use of sailing or rowing boats, with their low speeds, hindered the transport of living organisms from one place to another. The use of the steam boat, introduced around 1840 but widely diffuse around 1870-1880, opened the doors to more frequent arrivals and also to organisms from the American Continent. This technical innovation had an influence over the whole world economy, with its well-known grain crisis, and coincided in Sardinia with the arrival of Roman dairymen, producers of pecorino cheese and the beginning of the expansion of sheep farming which would continue uninterrupted until the present day. In this period of sudden social and environmental change, an insect was introduced which would turn out to be probably the most economically devastating agricultural pest in Europe: the Grape Phylloxera. The vineyard and wine business collapsed first in France then in Italy. The Phylloxera arrived in Sardinia in 1883 and wine production crashed a very short time later and only resumed after the distribution of American vine rootstock at the beginning of the 20th Century. From then, vine cultivation in Europe was modified with the essential use of this rootstock. Since then methods of transport have increased enormously in number and speed. The number of allochthonous and invasive species has increased proportionally: some of them along with exotic plants which are cultivated on the island, others following man in his activities. Often these new pests attack and destroy ornamental plants which have become part of the Sardinian landscape, causing it to change; just as often their presence requires methods of pest management which are different from the traditional methods on specific crops; finally in at least one case (the Asian tiger mosquito) they pose a threat to our health
Geosystemics View of Earthquakes
Earthquakes are the most energetic phenomena in the lithosphere: their study
and comprehension are greatly worth doing because of the obvious importance for society.
Geosystemics intends to study the Earth system as a whole, looking at the possible couplings among
the different geo-layers, i.e., from the earth’s interior to the above atmosphere. It uses specific universal
tools to integrate different methods that can be applied to multi-parameter data, often taken on different
platforms (e.g., ground,marine or satellite observations). Itsmain objective is to understand the particular
phenomenon of interest from a holistic point of view. Central is the use of entropy, together with other
physical quantities that will be introduced case by case. In this paper, we will deal with earthquakes,
as final part of a long-term chain of processes involving, not only the interaction between different
components of the Earth’s interior but also the coupling of the solid earth with the above neutral
or ionized atmosphere, and finally culminating with the main rupture along the fault of concern.
Particular emphasis will be given to some Italian seismic sequences.Publishedid 4121A. Geomagnetismo e PaleomagnetismoJCR Journa
Road traffic pollution and childhood leukemia: a nationwide case-control study in Italy
Background The association of childhood leukemia with traffic pollution was considered in a number of studies from 1989 onwards, with results not entirely consistent and little information regarding subtypes. Aim of the study We used the data of the Italian SETIL case-control on childhood leukemia to explore the risk by leukemia subtypes associated to exposure to vehicular traffic. Methods We included in the analyses 648 cases of childhood leukemia (565 Acute lymphoblastic–ALL and 80 Acute non lymphoblastic-AnLL) and 980 controls. Information on traffic exposure was collected from questionnaire interviews and from the geocoding of house addresses, for all periods of life of the children. Results We observed an increase in risk for AnLL, and at a lower extent for ALL, with indicators of exposure to traffic pollutants. In particular, the risk was associated to the report of closeness of the house to traffic lights and to the passage of trucks (OR: 1.76; 95% CI 1.03–3.01 for ALL and 6.35; 95% CI 2.59–15.6 for AnLL). The association was shown also in the analyses limited to AML and in the stratified analyses and in respect to the house in different period of life. Conclusions Results from the SETIL study provide some support to the association of traffic related exposure and risk for AnLL, but at a lesser extent for ALL. Our conclusion highlights the need for leukemia type specific analyses in future studies. Results support the need of controlling exposure from traffic pollution, even if knowledge is not complete
SAFE Project: An improved integrated system of earthquake physics study from ground and satellite observations
Trabajo presentado en 35th General Assembly of the European Seismological Commission, celebrado en Trieste (Italia), del 4 al 10 de septiembre de 2016The Swarm satellite mission by ESA has the primary goal to measure the magnetic signals from the Earth to
get new insights of the geomagnetic field and its sources. The SAFE (“Swarm for Earthquake study”) project
(funded by ESA in the framework "STSE Swarm+lnnovation", 2014) aims at applying the new approach of
geosystemics to the analysis of Swarm satellite electromagnetic data for investigating the preparatory phase of
large earthquakes. The main objective of the project is to explore the possible link between large earthquakes and
precursory electromagnetic anomalies detected by Swarm and ground based data (seismic, magnetic, GNSS, etc.).
This work will show some recent case studies analysed in the framework of the project.Peer reviewe
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