42 research outputs found
Robust time‐series analysis of the effects of environmental factors on the CoViD‐19 pandemic in the area of Milan (Italy) in the years 2020–21
No full textThe effects of environmental factors on the spread of the CoViD-19 pandemic have been widely debated in the scientific literature. The results are important for understanding the outbreak dynamics and for defining health measures of prevention and containment. Using multivariate autoregressive (AR) models and robust statistics of causality, this paper analyzes the effect of 19 time series (10 physical and 9 social) on 3 daily CoViD-19 series (infected, hospitalized, deaths) in the Milan area for about 16 months. Robust M-estimation shows the weak effect of climatic and pollution factors, while authority restrictions, people mobility, smart working and vaccination rate have a significant impact. In particular, the vaccination campaign is important for reducing hospitalizations and deaths
Alois Riehl. Un contributo al kantismo
No full textMonograph of A. Riehl, author or the famous Der philosophische Kritizismus and one of the protagonists of the early "zurück zu Kant"
Il problema del fondamento in F.A. Lange
No full textIl contributo di F.A. Lange, autore della nota "Geschichte des Materialismus und Kritik seiner Bedeutung in der Gegenwart", alla ripresa del pensiero kantiano. Centralità della "Kritik der reinen Vernunft" e della sua rivoluzione. La "psychophysische Organisation" alla base dell'attività teoretica.The contribution of Fr. Albert Lange, author of the famous "Geschichte des Materialismus und Kritik seiner Bedeutung in der Gegenwart", to the "zurück zu Kant". The key role of “Kritik der reinen Vernunft” and its revolution. The “psychophysische Organisation” at the base of theoretical activity
A proposito del de igne di Kant (1755)
No full textA panoramic glance on the cultural situation before de igne of Kant
Sequential Estimation and Control of Time-Varying Unit Root Processes with an Application to S&P Stock Price
No full textStock price series typically behave like random walks; that is, first-order auto-regressive models whose coefficients (roots) are on the unit circle. This article investigates time-varying unit roots (TVUR; that is, roots that wander about unity), and shows that their pattern is related to troughs and peaks of the observed series. Under the assumption of smooth evolution, exponentially weighted least squares (EWLS) can track roots that wander on the unit circle and so can detect turning points sequentially. This allows implementation of effective strategies of investment, which also provide optimization criteria for selecting the tuning coefficients. Extensive application to Standard & Poor's index and comparison with other methods shows the validity of the method
Seep-carbonates as indicators of global cooling events (Miocene, northern Apennines
No full textRecent studies in dating seep-carbonates suggest that their occurrence is controlled by climatic changes (TEICHERT et alii 2003). KIEL (2009) suggests that this correlation exists from the late Jurassic to Recent, and shows a statistically relevant correlations between the frequency of seep-carbonates in the past 150 Ma and low deep-water temperature and low sea- levels. In the Miocene of the northern Apennines, the abundance and the extent of the seep-carbonates from different tectonic-sedimentary settings, foredeep to satellite basins, provide a rare opportunity to study the tectonic and/or climatic controls on seepage (CONTI & FONTANA, 1999 A detailed stratigraphic and biostratigraphic study of carbonates and enclosing marls indicates that the stratigraphic horizon bearing seep-carbonates lies between the T. cf. T. quinqueloba AE (13.75 Ma) and the P. siakensis A1B (13.32 Ma) encompassing a time interval of about 400.000 years. Since the AE of T. cf. T. quinqueloba approximates the mid- Miocene global cooling event, we infer that the beginning of the seep-carbonate precipitation in the Vicchio Marls seems to be related to this climatic event (Fig. 2). We assume that the ascent and emission of methane-rich fluids may have been triggered by the pressure drop due to the eustatic fall associated with the Mi3b event, estimated in about 60 m (HILGEN et alii, 2009). A drop of the hydraulic pressure on the plumbin
The evolution of the Miocene platform-basin system in the northern Apennines: what can we learn from seep-carbonates?
No full textCold seep-carbonates documenting the expulsion of fluids enriched in methane have been identified in a variety of
basin margins and tectonic-sedimentary settings. A number of geological factors influences methane seep activity, but
primarily regional and local tectonics, mainly at the deformation front of accretionary prism and inner foredeep.
Tectonics constrains the fluid circulation system, with faults and fractures serving as conduits and channelling water
and methane up to the seafloor. Recent studies suggest that seep-carbonates occurrence is also controlled by climatic
changes and their formation seems to correlate with cold periods and sea level low-stand. A drop of the hydraulic
pressure on the plumbing system during sea level lowering in glacial phase could increase methane flows at seeps,
inducing carbonate precipitation. The correlation between methane-derived carbonates and climate has been recently
suggested for the Miocene of the northern Apennines by means of a sedimentological and biostratigraphic study of
seep-carbonates and the enclosing hemipelagic marls (Vicchio Formation) (Fontana et al., 2013). The study suggests a
correlation between the carbonate precipitation and the middle Miocene glacial cooling event (Mi3b). The triggering of
the ascent and emission of methane-rich fluids may be related to the eustatic fall and in turn to the water pressure
drop. A detailed stratigraphic and biostratigraphic study of seep-carbonates and enclosing marls in foredeep deposits of
the Tuscan-Romagna Apennines has allowed a precise dating of seepage in slope and basinal successions. The analysis
of the δ18O and δ13C records of carbonates, δ13Corg excursion of organic matter and TOC on the marls enclosing the
authigenic carbonates has been performed in order to verify a correlative trend in correspondence of the climatic
cooling event. A paleoecological study on benthic foraminifera assemblages has also allowed to detail these peculiar
environments. The events defined from this study in basinal deposits have been correlated with depositional changes
and discontinuity surfaces in the adjacent temperate-type carbonate platforms, and have contributed to the definition of
modes and rates of the demise of carbonate deposition. The identification of cold phases and lowering of sea level in
slope-basinal deposits and their detailed timing, may be a useful tool for correlation between deep depositional setting
and coeval shallow-water successions. This approach may also provide important constrains in the reconstruction of the
evolution of the Miocene platform-basin system in this complex compressive setting of the northern Apennines.
Fontana D., Conti S., Grillenzoni C., Mecozzi S., Petrucci F. & Turco E. 2013. Evidence of climatic control on
hydrocarbon seepage in the Miocene of the northern Apennines
Alternaria spores at different heights from the ground
No full textBackground: Alternaria tenuis (Alt) is one of the main allergens in pediatric age. In temperate climates, airborne Alt spores are detectable from May to November with peaks in late summer and autumn. Sensitized children display symptoms even in the absence of airborne Alt spores. Alt spore concentration, as well as pollen, is usually detected by fixed devices located on the roof of a building at a height of 10-20 m. The aim of the current study is to find out whether ground-level (50 cm) Alt spore concentrations are different from those at roof-top level, even during low-concentration periods. Methods: Alt samples were taken simultaneously using a Hirst fixed volumetric collector (FVC) placed on a 15 m-high roof and by a portable volumetric collector (PVC). Firstly, the results of FVC and PVC, both placed on the roof-top, were compared to verify the correlation coefficient of the two samplers. Subsequently, the PVC was placed 50 cm above the ground in a courtyard (30 samplings) and in private green areas (50 samplings). The results were compared by statistical analysis (Student's t-test or K-S test). Results: The values of the 20 samples taken jointly in summer time (FVC 195 +/- 134 spores/m(3); PVC = 134 +/- 131 spores/m(3)) showed a good correlation between the two samplers (r = 0.850; P < 0.01), with a correction factor equal to 1.177. 1. Thirty samples obtained in summer and winter when the PVC was positioned in an enclosed courtyard directly below the FVC showed no significant difference (PVC, 181 +/- 194 spores/m(3); FVC, 152 +/- 145 spores/m(3); P = 0.221). 2. Fifty samples taken by PVC placed in private green areas in a low-concentration period, showed significantly higher concentrations than by FVC: PVC, 531 +/- 925 spores/m(3); FVC, 25 +/- 51 spores/m(3) (K-S test: P < 0.0001). In particular, 33 samples taken in winter when Alt counts by FVC were <10 spores/m(3) still demonstrated highly significant differences: PVC, 398 +/- 961 spores/m(3); FVC, 2.0 +/- 2 spores/m(3) (K-S test: P < 0.0001). Conclusion: Our results lead to the conclusion that Alt spore concentration is significantly higher at ground level in the presence of vegetation, even when the spore concentration is very low (<10 spores/m(3)). These results further suggest that the individual's exposure to Alt, especially in the case of children, is underestimated by samples taken at roof-top level by FVC
Evidence of climatic control on hydrocarbon seepage in the Miocene of the northern Apennines: The case study of the Vicchio Marls.
No full textEvidence of climatic control on hydrocarbon seepage in the Miocene of the northern Apennines: The case study of the Vicchio Marls
No full textThe Vicchio outcrop in the Tuscan Apennines contains excellent exposures of a Miocene methane-derived carbonate system, made up of more than 80 carbonate bodies enclosed in marly sediments. Facies analysis, composition and a detailed biostratigraphic study of the carbonates and enclosing Vicchio Marls allowed us to document the role of climatic changes and eustasy on seepage in these ancient deposits. Results of our study indicate that the stratigraphic horizon bearing seep-carbonates is constrained by two planktonic foraminiferal events, the Acme End (AE) of Turborotalita cf. T.quinqueloba (13.75Ma) and the Acme1 Beginning (A1B) of Paragloborotalia siakensis (13.32Ma), encompassing about 400,000 years. The AE of T. cf. T.quinqueloba approximates the mid-Miocene global cooling event (Mi3b), as defined by the δ18O maxima (13.78Ma). The glacio-eustatic sea level drop associated with this cooling event is estimated to be approximately 60m. Assuming that the highest rates of glacio-eustatic sea level fall coincide with δ18O maxima, the timing of the seepage onset (at about 13.75Ma) is concomitant with the phase of sea level-lowering. The ascent and emission of methane-rich fluids may have been triggered by pressure drop due to the eustatic fall associated with the Mi3b event. The moderate intensity of fluid expulsion is suggested by the lack of brecciation, by the scarcity of detrital particles in the carbonates and by the pervasive occurrence of carbonate in the enclosing marls. This type of seepage differs from focused fault-confined fluid flows, typical of other tectonically controlled Apenninic seep-carbonates. © 2013 Elsevier Ltd
