The Bisymplectomorphism Group of a Bounded Symmetric Domain

We determine the group of diffeomorphisms of a bounded symmetric domain, which preserve simultaneously the hyperbolic and the at symplectic form. *Research partially supported by GNSAGA (INdAM) and MIUR of Italy; MIUR Project “Geometric Properties of Real and Complex Manifolds” (PRIN05). **Research partially supported by GNSAGA (INdAM) and MIUR of Italy; MIUR Project “Geometric Properties of Real and Complex Manifolds” (PRIN05). ***Part of this work was done in July 2007 during a visit of G. Roos at Politecnico di Torino; visit supported by GNSAGA (INdAM) and MIUR of Italy; MIUR Project “Geometric Properties of Real and Complex Manifolds: (PRIN05).     

Acceptor levels in indium selenide. An investigation by means of the Hall effect,deep-level-transient spectroscopy and photoluminescence

Acceptor levels related to I, II, IV, and V group impurities in indium selenide are studied by means of the Hall effect, deep-level-transient spectroscopy (DLTS) and photoluminescence. Activation energies for hole concentrations in the range from 200 to 300 meV have been measured. A reversible change of sign of the Hall voltage has been observed below 215 K. This behaviour can be explained through a model in which acceptor levels are assumed to be shallow and interlayer planar precipitates of ionized shallow donors create potential wells that behave as deep donors and in which a low concentration of bidimensional free electrons can exist. This model also explains the capacitance-voltage characteristics of both ITO/p-InSe and Au/p-InSe barriers. DLTS results are coherent with this model: hole traps in high concentration located about 570 meV above the valence band are detected. Photoluminescence also confirms the shallow character of acceptor levels. A broad band whose intensity is related to p conductivity appears in the PL spectra of low resistivity p-InSe. The shape and temperature dependence of this band can be explained through self-activated photoluminescence in a complex center in which the ground acceptor level must be at about 50 meV above the valence band.     

Relative acidities and structure analysis of cis and trans isomers of 1,5‐oxazaspiro[5.5] undecane derivatives by multinuclear magnetic resonance

The relative acidities of the cis and trans isomers of a series of 1,5‐oxazaspiro[5.5]undecane derivatives were determined by measuring ΔpK in acid‐base titrations followed by ¹ H NMR. Relative structural stabilities were determined by measuring substituent chemical shift and γ‐gauche effects in ¹³C, ¹⁵N, and ¹⁷O NMR. Crystallographic characterization of a model spiro[5.5]undecane is presented to support the basicity in solid state. Copyright © 2010 John Wiley & Sons, Ltd.     

A pilot study for the statistical treatment of nutritional parameters in the quality control of canned fishing goods.

This pilot study was derived as a consequence of European Directives 496/90 and 493/91 in which a regulation on the labeling of canned fishing goods was established. The study was intended primarily to assess whether different Spanish canned fishing goods might be differentiated by their basic nutritional composition (i.e., ash, chlorine as NaCl, fat, humidity, total proteins, and dry residue) and, second, to study each particular type of good. Accordingly, a univariate nonparametric statistical test and 2 multivariate chemometric techniques (factor and cluster analyses) were used. The pilot study revealed that (1) the basic nutritional variables did not allow a clear distinction among canned goods when different commodities were considered, but they seemed useful for obtaining information for only one type of good; and (2) the variables that gave the most useful information to visualize the appearance of groups in the data sets were humidity, dry residue, fat, and proteins, although their particular usefulness was found to be different when different species were considered.