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203. Hydrodynamic instability of the solar nebula in the presence of a planetary core

Author

Perri, F and Cameron, A. G. W

Subjects
Lunar And Planetary Exploration
Abstract

When a planetary core composed of condensed matter accumulates in the primitive solar nebula, the gas in the nebula becomes gravitationally concentrated as an envelope about the planetary core. An analysis of models of such gaseous envelopes indicates that giant planets (such as Jupiter and Saturn) formed in a massive primitive solar nebula of the type constructed by Cameron and Pine (1973). When the mass of the accumulating planetary core becomes sufficiently great, the surrounding gaseous envelope will become hydrodynamically unstable against collapse onto the planetary core. Much of the surrounding gas also may be compressed onto the core by the background pressure of the gas.

Published
1974
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214. Hydrogen flash in stars.

Author

Perri, F and Cameron, A. G. W

Subjects
Space Sciences
Abstract

The initial adiabat of the gas in a flat rotating disk is estimated in several ways. A star which can be represented by a polytrope of index 1.5 is considered. The central conditions are determined through specification of the total mass and the adiabatic constant. The values for the temperature and the density of the center are much higher than now exist at the center of the sun. It is possible that the ignition of hydrogen-burning reactions at the center of the disk can be accompanied by a thermal runaway.

Published
1973
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215. Lateral spreading phenomena and weathering processes from the Tropea area (Calabria, southern Italy).

Author

Ietto, F., Perri, F., and Fortunato, G.

Subjects
LANDSLIDE hazard analysis, HYDROGEOLOGICAL modeling, WEATHERING, DEFORMATIONS (Mechanics), LANDSLIDE prediction, SPREADING centers (Geology), ECOLOGICAL risk assessment, GEOMORPHOLOGY
Abstract

This paper describes the lateral spreading landslides, the weathering processes and the hydrogeological risk patterns of the NW sector of Monte Poro (Calabria, southern Italy), based on the development of a multidisciplinary research. The tectonic uplift of the area combined with the litho-structural features of the sedimentary deposits overlying the intensely weathered granitoid complex produces important gravitational phenomena characterized by lateral spreading kinematics. The contact between deposits with a different behaviour, together with the high slope energy related to the tectonic uplift processes, is the main cause of widespread fracturing and disjoint of the lithologies associated with lateral spreading phenomena. These phenomena are also testified by the various trenches and cracks characterized by a parallel orientation relatively to the main fluvial incisions. Measures of these deformations were obtained with a quantitative result by the use of 'Interferometric Stacking' methods. The experimental results confirm this morphological scenario characterized by strain values ranging between 20 and 25 mm/year relatively to the landslides detected. Geomorphological analysis of the drainage basins in the study area indicates a juvenile stage of the stream networks. This pattern is consistent with the high rate of tectonic uplift of the area, hence the continuous rejuvenation of the stream networks and their low level of hierarchy. These conditions of geomorphic equilibrium of the stream networks, the widespread occurrence of geological instability in continuous evolution, are the main causes of high hydrogeological risk conditions for this coastal area. [ABSTRACT FROM AUTHOR]

Published
2015
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224. Urinary 15NH4 test

Author

Perri, F., Andriulli, A., Krumbiegel, Peter, Perri, F., Andriulli, A., and Krumbiegel, Peter

Published
1998

238. Cruveilhier-Baumgarten syndrome: an efficient spontaneous portosystemic collateral preventing oesophageal varices bleeding

Author

Caturelli, E, Pompili, Maurizio, Squillante, Mm, Sperandeo, G, Carughi, S, Sperandeo, M, Perri, F, Andriulli, A, Cellerino, C, Rapaccini, Gian Ludovico, Pompili, Maurizio (ORCID:0000-0001-6699-7980), Rapaccini, Gian Ludovico (ORCID:0000-0002-6467-857X), Caturelli, E, Pompili, Maurizio, Squillante, Mm, Sperandeo, G, Carughi, S, Sperandeo, M, Perri, F, Andriulli, A, Cellerino, C, Rapaccini, Gian Ludovico, Pompili, Maurizio (ORCID:0000-0001-6699-7980), and Rapaccini, Gian Ludovico (ORCID:0000-0002-6467-857X)

Abstract

The protective role of large spontaneous portosystemic shunts in oesophageal varices bleeding due to portal hypertension in liver cirrhosis is still debated. A series of 20 consecutive patients with haemodynamically efficient collaterals involving the para-umbilical-epigastric venous route (evaluated by Echo-Doppler flowmetry) is reported. All patients presented absent or mild oesophageal varices at endoscopy. During a mean follow-up period of 23.5 months, no patient developed large varices or experienced variceal bleeding. Hepatic encephalopathy was present in 35% of patients. Haemodynamically efficient spontaneous portosystemic shunts may protect cirrhotic patients from the risk of oesophageal varices forming and bleeding. The diversion of large amounts of blood from portal to systemic circulation correlates with the higher trend of hepatic encephalopathy in these patients.

Published
1994

249. Diagnosis

Author

Klein, P. D., primary, Logan, R. P.H., additional, Amarri, S., additional, Andriulli, A., additional, Iaquinto, G., additional, Luzza, F., additional, Garcia, Pajarès J.M., additional, Pazzi, P., additional, Perri, F., additional, Pozzato, P., additional, Roda, A., additional, Vaira, D., additional, and Zagari, R. M., additional

Published
1997
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