Twistor Theory for co-CR quaternionic manifolds and related structures

In a general and non metrical framework, we introduce the class of co-CR quaternionic manifolds, which contains the class of quaternionic manifolds, whilst in dimension three it particularizes to give the Einstein-Weyl spaces. We show that these manifolds have a rich natural Twistor Theory and, along the way, we obtain a heaven space construction for quaternionic-Kaehler manifolds.Comment: 19 page

Hermitian and KAhler submanifolds of a quaternionic Kahler manifold

http://projecteuclid.org/euclid.ojm/115349255

The importance of the fresh water outflow on a station situated in front of the Po river (Po di Goro)

The fractions of dissolved organic and inorganic nitrogen and phosphorus in sea water samples were monitored at the station S1, placed in front of the Po River mouth (44?44\u2770"N, 12?27\u2741"E). The aim was to extent our knowledge about the biochemical situation in an area that is highly influenced by fresh water loads by the .. 288 largest Italian river, and to estimate the portions of organic and inorganic nitrogen and phosphorus that were lost from the System due to physical and biochemical interactions. For this purpose, we chose to examine a sampling period with scarce river outflow (April 1995) and one with greater outflow (July 1995). Despite great nutrient loads in both sampling periods, our estimates revealed that almost the whole fraction of inorganic phosphorus (up to 92 % at April) and a part of the inorganic nitrogen (30 % at April and 42 % at July) was readily consumed at the station. Surprisingly the dissolved organic fraction of nitrogen (DON) was much greater at the station (up to 3120 % in April) than in the river water, and it constituted a conspicuous part of the total dissolved nitrogen in the study area. On the contrary, the dissolved organic fraction of phosphorus (DOP) did not accumulate in the coastal area, compared to the river water

Kahler submanifolds of Wolf Spaces

We classify the Kahler submanifolds of Wolf spaces i.e. Quaternionic Kahler symmetric spaces, with parallel second fundamental for

Kahler submanifolds of Wolf Spaces

We classify the Kahler submanifolds of Wolf spaces i.e. Quaternionic Kahler symmetric spaces, with parallel second fundamental form

A multidisciplinary approach to the investigation of "La Caverna dell'Antimateria" (1958–1959) by Pinot Gallizio

Background: This study concerns the application of non-invasive and micro-invasive analyses for the study of a contemporary artwork entitled La Caverna dell'Antimateria ("The Cave of Antimatter") which was created by Pinot Gallizio in 1958–1959. The work represents one of the most significant examples of industrial painting. It consists of a total of 145 meters of painted canvas, designed in order to cover the entire floor plan of the Rene Drouin gallery in Paris, where it was displayed for the first time. Gallizio wanted to create an environment in which visitors could find themselves immersed in painting, in what he termed as a "work-environment". Non-invasive (Fibre Optic Reflectance Spectroscopy) and micro-invasive analyses (Fourier Transform Infrared and micro-Raman Spectroscopies, Pyrolysis-Gas Chromatography and Gas Chromatography/Mass Spectrometry) were performed on three of the canvases which constitute this work of art in order to obtain information regarding the artistic materials used by Gallizio. Results: Pigments and unconventional materials (such as metal wires, sand) are present in the canvases that form the ceiling. The colours are unevenly distributed on the surface, thus revealing large areas of the white preparation below. In the canvas of the wall, instead, the paint is applied more uniformly and gives a dark colour cast. The analytical results led to the identification of many of the materials used by Gallizio. The pictorial palette consists of both inorganic and organic pigments, while polyvinylacetate, pure or mixed with a siccative oil, was identified as a binder thus confirming what was reported by the artist in his notes. Conclusions: The results of this research provide information concerning the artistic technique used by Pinot Gallizio. The analyses were successfully performed both in situ and on micro-samples in order to characterise the pigments of the coloured area, the ground layer and the organic binders