Non-Commutative Complete Mellin Representation for Feynman Amplitudes

We extend the complete Mellin (CM) representation of Feynman amplitudes to the non-commutative quantum field theories. This representation is a versatile tool. It provides a quick proof of meromorphy of Feynman amplitudes in parameters such as the dimension of space-time. In particular it paves the road for the dimensional renormalization of these theories. This complete Mellin representation also allows the study of asymptotic behavior under rescaling of arbitrary subsets of external invariants of any Feynman amplitude.Comment: 14 pages, no figur

Image processing method as a supporting tool for wood species identification

Examination of wood sections using microscopy is often not very satisfactory for species identifcation, and this may be the case for samples taken from objects needing restoration. This could be caused by various parameters, namely the small size of the section, condition of the section related to its age or degradation, finishes penetrating the wood material as well as sections not covering a representative area to have an objective and accurate wood identification. An image analysis method based on ImageJ, an image processing program intended for medical micrscopy, was used in this work. The method is useful for wood because it offers an objective quantitative way to separate and measure anatomical structures of the section allowing statistical analysis of the data to be carried out. This is a case study related to identifying samples from three furniture pieces needing restoration. Microslides were prepared from small samples of each furniture unit. These were observed with transmitted light microscopy. Each sample was identified by examining the microscopic images, which were interpreted for their common but also specific features and characteristics by means of ImageJ analysis and compared with reference microscopic images of known species and their characteristics provided by the literature. The species identified in this study were found to have diffuse pores. Further work should address more wood species, including softwoods, to check the usefulness of the image processing method on various situations and to understand its limitations

Wood Species for the Biedermeier Furniture - A Microscopic Characterisation for Scientific Conservation

Wood species identification is an important, compulsory step in the scientific conservation of the historic furniture as a significant part of the cultural heritage. It is known that a visual examination of an investigated sample does not always bring enough information about the original species and that a microscopic approach is more reliable. Species identification can be performed if the microscopic images are interpreted for common, but also for specific features and characteristics, by means of identification keys and in comparison with reference images. This paper provides the microscopic characterization with identification keys for six hardwood species, some of the most common in Biedermeier furniture (elm - Ulmus glabra Huds., cherry - Prunus avium L., walnut - Juglans regia L.,pear - Pyrus communis L., aspen - Populus tremula L., African mahogany - Khaya ivorensis A. Chev.). The characterization can be used for wood identification purposes by laboratories working in the field of cultural heritage wood conservation. This work is part of a recent research project that aims to develop and implement a scientific investigation for furniture conservation

Determining the probability of locating peaks using computerized peak-location methods in gamma-ray spectra as a function of the relative peak-area uncertainty

The probabilities of locating peaks with a high relative peak-area uncertainty were determined empirically with nine types of peak-location software used in laboratories engaged in gamma-ray spectrometry measurements. It was found that it is not possible to locate peaks with a probability of 0.95, when they have a relative peak-area uncertainty in excess of 50%. Locating peaks at these relatively high peak-area uncertainties with a probability greater than 0.95 is only possible in the library-driven mode, where the peak positions are supposed a-priori. The deficiencies of the library-driven mode and the possibilities to improve the probabilities of locating peaks are briefly discussed. © 2019 Elsevier Lt

A Surface Scientist's view on Spectroscopic Ellipsometry

none1noneMaurizio CanepaCanepa, Maurizi