First results of systematic studies done with different types of Silicon Photomultipliers

The presented results are obtained during the first steps taken in order to develop a setup and measurement procedures which allow to compare properties of diverse kinds of silicon photomultipliers. The response to low-intensity light was studied for silicon photomultipliers produced by CPTA (Russia), Hamamatsu (Japan), ITC-irst (Italy) and SensL (Ireland).Comment: 3 pages, 3 figures, proceedings of the Internationa Linear Collider Workshop LCWS2007, Hamburg, German

First results of comparative studies of silicon photomultipliers

The presented results are obtained during the first steps taken in order to develop a set-up and measurement procedures which allow to compare properties of diverse samples of silicon photomultipliers. The response to low-intensity light was studied for silicon photomultipliers produced by CPTA (Russia), Hamamatsu(Japan), ITC-irst (Italy) and SensL (Ireland)

Approach to a rational rotation number in a piecewise isometric system

We study a parametric family of piecewise rotations of the torus, in the limit in which the rotation number approaches the rational value 1/4. There is a region of positive measure where the discontinuity set becomes dense in the limit; we prove that in this region the area occupied by stable periodic orbits remains positive. The main device is the construction of an induced map on a domain with vanishing measure; this map is the product of two involutions, and each involution preserves all its atoms. Dynamically, the composition of these involutions represents linking together two sector maps; this dynamical system features an orderly array of stable periodic orbits having a smooth parameter dependence, plus irregular contributions which become negligible in the limit.Comment: LaTeX, 57 pages with 13 figure

Evaluation of indigenous entomopathogenic nematodes as potential biocontrol agents against popillia japonica (Coleoptera: Scarabaeidae) in Northern Italy

The natural presence of entomopathogenic nematodes (EPNs) has been investigated in the Piedmont region (Northern Italy) in areas infested by the Japanese beetle Popillia japonica. Thirty-nine out of 155 soil samples (25.2%) were positive for EPNs. Most of the samples contained only steinermatids (92.3%), 5.1% contained heterorhabditids, and one sample (2.6%) contained both genera. All the recovered isolates were identified at species level both morphologically and molecularly. Steinernema carpocapsae was the most abundant and it was mainly distributed in open habitats, such as perennial meadows, uncultivated soils, and cropland, characterized by sandy loam soil texture and acidic pH. Steinernema feltiae has been found associated mainly with closed habitats such as coniferous and deciduous woodland, characterized by sandy loam-texture and extremely acidic soil. The three isolates of Heterorhabditis bacteriophora were collected only in open habitats (perennial meadows and uncultivated fields) characterized by strongly acidic soils with sandy loam texture. The virulence of all EPN natural strains was evaluated by laboratory assays against P. japonica third-instar larvae collected during two different periods of the year (spring, autumn). The results showed that larval mortality was higher for pre-wintering larvae than post-wintering ones. The five more promising EPN isolates were tested in the semi-field assay in which H. bacteriophora natural strains have been shown to be more efficient in controlling P. japonica grubs. All of these results are finally discussed considering the use of these natural EPNs as biological control agents against P. japonica, within an eco-friendly perspective of management

Distribution and paleoenvironmental framework of middle Miocene marine vertebrates along the western side of the lower Ica Valley (East Pisco Basin, Peru).

We report 130 vertebrate fossils preserved as bony elements and the co-occurring assemblage of fish teeth and spines from the lower strata of the Pisco Formation exposed along the western side of the lower Ica Valley (East Pisco Basin, Peru). Geological mapping at 1:10,000 scale reveals that all these fossils originate from the Langhian–Serravallian P0 allomember. In the study area, P0 is up to ∼40 m thick and features a sandy lower portion, reflecting shoreface deposition, that fines upwards into a package of offshore silts. Marine vertebrates only occur in the lower sandy layers and include whales, dolphins, reptiles, birds, and bony and cartilaginous fishes. The reconstructed paleoenvironment is consistent with a warm-water, marginal marine setting with a strong connection to the open ocean. This work helps to elucidate the rich yet still poorly understood middle Miocene portions of the Pisco Formation, and highlights the need to conserve this outstanding Fossil-Lagerstätte

Ice XII in its second regime of metastability

We present neutron powder diffraction results which give unambiguous evidence for the formation of the recently identified new crystalline ice phase[Lobban et al.,Nature, 391, 268, (1998)], labeled ice XII, at completely different conditions. Ice XII is produced here by compressing hexagonal ice I_h at T = 77, 100, 140 and 160 K up to 1.8 GPa. It can be maintained at ambient pressure in the temperature range 1.5 < T < 135 K. High resolution diffraction is carried out at T = 1.5 K and ambient pressure on ice XII and accurate structural properties are obtained from Rietveld refinement. At T = 140 and 160 K additionally ice III/IX is formed. The increasing amount of ice III/IX with increasing temperature gives an upper limit of T ~ 150 K for the successful formation of ice XII with the presented procedure.Comment: 3 Pages of RevTeX, 3 tables, 3 figures (submitted to Physical Review Letters

Cohomology of bundles on homological Hopf manifold

We discuss the properties of complex manifolds having rational homology of $S^1 \times S^{2n-1}$ including those constructed by Hopf, Kodaira and Brieskorn-van de Ven. We extend certain previously known vanishing properties of cohomology of bundles on such manifolds.As an application we consider degeneration of Hodge-deRham spectral sequence in this non Kahler setting.Comment: To appear in Proceedings of 2007 conference on Several complex variables and Complex Geometry. Xiamen. Chin

Weyl's law and quantum ergodicity for maps with divided phase space

For a general class of unitary quantum maps, whose underlying classical phase space is divided into several invariant domains of positive measure, we establish analogues of Weyl's law for the distribution of eigenphases. If the map has one ergodic component, and is periodic on the remaining domains, we prove the Schnirelman-Zelditch-Colin de Verdiere Theorem on the equidistribution of eigenfunctions with respect to the ergodic component of the classical map (quantum ergodicity). We apply our main theorems to quantised linked twist maps on the torus. In the Appendix, S. Zelditch connects these studies to some earlier results on `pimpled spheres' in the setting of Riemannian manifolds. The common feature is a divided phase space with a periodic component.Comment: Colour figures. Black & white figures available at http://www2.maths.bris.ac.uk/~majm. Appendix by Steve Zelditc