Censimento autunnale degli uccelli acquatici Non-passeriformes in alcuni laghi e stagni della Sardegna Nord-Occidentale

The author reports on a study carried out regarding the situation of avifauna in autumn in the ponds of Calich, Casaraccio, Pilo, Platamona and in the lakes of Baratz, Cuga and Surigheddu (North-Western Sardinia) with the aim to classify migratory and sedentary birds. The author classifies 30 species belonging to 13 different families. The most numerous family is that of Anatidae (9 species); while the most numerous species is that of Fulica atra (4642 specimen). The species common to all environments are: Podiceps ruficollis, Fulica atra, Larus argentatus michahellis

Osservazioni sulla avifauna della Nurra

A research into the Avifauna of the Nurra (North-East Sardinia) has been carried out. 164 species in all have been included in the census: 83 of themare nest-building, 12 probably- il possible nest- building, 69 not nestbuilding. 5 species of them are extint in recent years, 5 of them are of international importance, 3 of them of national importance and 5 of regional importance. The ambients which have a greater number of nest-building species are: «The agricultural zones » which have 43 species, « The coastal ponds » which ave 30 species, « The bush and forest» which have 30 species, « The rocky coasts and the small islands» which have 29 species. The ecosystems with a greater number of species menaced with extinction are: «The coastal ponds», «The rocky coastsand small islands» and «The inland rocky coasts» and «The steppes and the grasslands ». Proposal for the protection of the most important 'ecosystems have been made

Osservazioni sull'Avifauna della Laguna del Calich e considerazioni sulle possibili conseguenze degli interventi di bonifica

An ornithological study was carried out on the lagoon of Calich. A census was made on 100 species of birds of which 66 «Non Passeriformes» and 34 «Passeriformes». 65 species are or have been migrators. 14 species are or have been nesting annually, 6 are nesting but not wintering, 15 are probably nesting. The category with the largest number of species proved to be the CHARADRUFORMES with 25 species. The most numerous species in Anas querquedula. 6 species (Podiceps ruficollis, Ardea purpurea, Ixobrychus minutus, Circus aeruginosus, Porphyrio porphyrio, Fulica atra) are extinct owing to the resu1ts of land rec1amation in 1938-40. As a second land rec1amation is in progress, some proposals are made for the ornithologycal protection and the conservation of the ecological system of Calich

Volatility and stock market direction: a study on emerging markets.

Volatility indices, such VIX, can be used for determining stock market direction. In this paper, we analyze the relationship between changes in the VIX direction and changes in the turning point of S&P 500 and the MSCI Latin-America Emerging Market index, in order to see whether they anticipate the changes. Also, the volatility of emerging markets measured by standard deviation and their relationship with the stock market movements within this market are calculated, since the greater the value of the volatility, the greater the likelihood of a rise or fall. In order to locate the turning point and the upward and downward phases of the cycles, empirical methods are applied and are characterized by using a set of decision rules that reflect the practical experience gained by analysts. Our conclusions include: Turning points, or peaks and troughs, in the VIX are coincident with peaks and troughs in the opposite direction for the S&P 500 index and in emerging markets

Osservazione di uccelli rari in Sardegna

The authors refer to certain sightings of rare birds for Sardinia.The Species observed are: Storm Petrel, Gannet, White Stork, Blak Stork, Great Skua. It was also reported on breeding of Storm Petrel on a small island in the north-west of Sardinia

Can observed randomness be certified to be fully intrinsic?

Randomness comes in two qualitatively different forms. Apparent randomness can result both from ignorance or lack of control of degrees of freedom in the system. In contrast, intrinsic randomness should not be ascribable to any such cause. While classical systems only possess the first kind of randomness, quantum systems are believed to exhibit some intrinsic randomness. In general, any observed random process includes both forms of randomness. In this work, we provide quantum processes in which all the observed randomness is fully intrinsic. These results are derived under minimal assumptions: the validity of the no-signalling principle and an arbitrary (but not absolute) lack of freedom of choice. The observed randomness tends to a perfect random bit when increasing the number of parties, thus defining an explicit process attaining full randomness amplification.Comment: 4 pages + appendice

Resoconto annuale dei Vertebrati terrestri della Sardegna: 1987

Sightings of 111 bird species in 1987 are briefly reported

Manipulation of single-photon states encoded in transverse spatial modes: possible and impossible tasks

Controlled generation and manipulation of photon states encoded in their spatial degrees of freedom is a crucial ingredient in many quantum information tasks exploiting higher-than-two dimensional encoding. Here, we prove the impossibility to arbitrarily modify $d$-level state superpositions (qu$d$its) for $d>2$, encoded in the transverse modes of light, with optical components associated to the group of symplectic transforms (Gaussian operations). Surprisingly, we also provide an explicit construction of how non-Gaussian operations acting on mode subspaces do enable to overcome the limit $d=2$. In addition, this set of operations realizes the full SU(3) algebra.Comment: Published in PR