University of Cagliari

About: University of Cagliari is a education organization based out in Cagliari, Italy. It is known for research contribution in the topics: Population & Dopamine. The organization has 11029 authors who have published 29046 publications receiving 771023 citations. The organization is also known as: Università degli Studi di Cagliari & Universita degli Studi di Cagliari.

Tephrostratigraphy, chronology and climatic events of the Mediterranean basin during the Holocene: an overview

Abstract: The identification and characterisation of high-frequency climatic changes during the Holocene requires natural archives with precise and accurate chronological control, which is usually difficult to achieve using only 14C chronologies. The presence of time-spaced tephra beds in Quaternary Mediterranean successions represents an additional, independent tool for dating and correlating different sedimentary archives. These tephra layers are potentially useful for resolving long-standing issues in paleoclimatology and can help towards correlating terrestrial and marine paleoclimate archives. Known major tephras of regional extent derive from central and southern Italy, the Hellenic Arc, and from Anatolia. A striking feature of major Holocene tephra deposition events in the Mediterranean is that they are clustered rather than randomly distributed in time. Several tephra layers occurred at the time of the S1 sapropel formation between c. 8.4 and 9.0 ka BP (Mercato, Gabellotto-Fiumebianco/E1, Cappadocia) and ot...

Profound decrease of mesolimbic dopaminergic neuronal activity in morphine withdrawn rats.

Abstract: The spontaneous neuronal activity of meso-accumbens dopaminergic neurons was recorded in unanesthetized rats withdrawn from chronic morphine administration (15 days) by means of single cell extracellular recording techniques coupled with antidromic identification from the nucleus accumbens. Twenty-four h after last morphine administration, firing rate and burst firing were found to be drastically reduced and the relative refractory periods of the same neurons were prolonged in morphine-dependent rats as compared with chronic saline-treated controls. The number of spontaneously active dopaminergic neurons, however, did not differ between the two groups. Administration of morphine restored electrophysiological parameters. When rats were tested 2 h after last morphine administration, i.v. challenge with the opiate antagonist naloxone caused an abrupt and virtually complete reduction of dopaminergic firing rate, burst rate and a prolongation of the relative refractory period. These effects were not observed in control rats. The results indicate that the mesolimbic dopaminergic system is tonically reduced in its activity during morphine withdrawal syndrome and considering its role in the reinforcing properties of opioids, its depressed activity during the morphine withdrawal syndrome may bear relevance for the dysphoric state associated to morphine withdrawal in humans.

Transformation of a Star into a Planet in a Millisecond Pulsar Binary

Abstract: Millisecond pulsars are thought to be neutron stars that have been spun-up by accretion of matter from a binary companion. Although most are in binary systems, some 30% are solitary, and their origin is therefore mysterious. PSR J1719−1438, a 5.7-millisecond pulsar, was detected in a recent survey with the Parkes 64-meter radio telescope. We show that this pulsar is in a binary system with an orbital period of 2.2 hours. The mass of its companion is near that of Jupiter, but its minimum density of 23 grams per cubic centimeter suggests that it may be an ultralow-mass carbon white dwarf. This system may thus have once been an ultracompact low-mass x-ray binary, where the companion narrowly avoided complete destruction.