Transmuting CHY formulae

© The Author(s) 2019.The various formulations of scattering amplitudes presented in recent years have underlined a hidden unity among very different theories. The KLT and BCJ relations, together with the CHY formulation, connect the S-matrices of a wide range of theories: the transmutation operators, recently proposed by Cheung, Shen and Wen, provide an account for these similarities. In this note we use the transmutation operators to link the various CHY integrands at tree-level. Starting from gravity, we generate the integrands for YangMills, biadjoint scalar, Einstein-Maxwell, Yang-Mills scalar, Born-Infeld, Dirac-Born-Infeld, non-linear sigma model and special Galileon theories, as well as for their extensions. We also commence the study of the CHY-like formulae at loop level.Peer reviewe

Prediction of sinus rhythm maintenance following DC-cardioversion of persistent atrial fibrillation – the role of atrial cycle length

BACKGROUND: Atrial electrical remodeling has been shown to influence the outcome the outcome following cardioversion of atrial fibrillation (AF) in experimental studies. The aim of the present study was to find out whether a non-invasively measured atrial fibrillatory cycle length, alone or in combination with other non-invasive parameters, could predict sinus rhythm maintenance after cardioversion of AF. METHODS: Dominant atrial cycle length (DACL), a previously validated non-invasive index of atrial refractoriness, was measured from lead V1 and a unipolar oesophageal lead prior to cardioversion in 37 patients with persistent AF undergoing their first cardioversion. RESULTS: 32 patients were successfully cardioverted to sinus rhythm. The mean DACL in the 22 patients who suffered recurrence of AF within 6 weeks was 152 ± 15 ms (V1) and 147 ± 14 ms (oesophagus) compared to 155 ± 17 ms (V1) and 151 ± 18 ms (oesophagus) in those maintaining sinus rhythm (NS). Left atrial diameter was 48 ± 4 mm and 44 ± 7 mm respectively (NS). The optimal parameter predicting maintenance of sinus rhythm after 6 weeks appeared to be the ratio of the lowest dominant atrial cycle length (oesophageal lead or V1) to left atrial diameter. This ratio was significantly higher in patients remaining in sinus rhythm (3.4 ± 0.6 vs. 3.1 ± 0.4 ms/mm respectively, p = 0.04). CONCLUSION: In this study neither an index of atrial refractory period nor left atrial diameter alone were predictors of AF recurrence within the 6 weeks of follow-up. The ratio of the two (combining electrophysiological and anatomical measurements) only slightly improve the identification of patients at high risk of recurrence of persistent AF. Consequently, other ways to asses electrical remodeling and / or other variables besides electrical remodeling are involved in determining the outcome following cardioversion

Neural Networks in Economics: Background, Applications and New Developments

Neural Networks have been developed in the sixties as a device for classification and pattern recognition. While the approach has been inspired from Neuroscience its attractiveness lies in the ability to "learn", i.e. to generalize as to yet unseen observations. One aim of this paper is to give an introduction into the technique of Neural Networks and an overview on the most current implementations. To do so, we start from statistical learning theory to introduce some notions to be of importance later. Then, we give an overview of the general principles of neural networks and of their use in the field of Economics. A second purpose is to introduce a recently developed Neural Network Learning technique, so called Support Vector Network Learning, which is an application of an idea from statistical learning theory. This approach has shown very promising results on problems with a limited amount of training examples. Moreover, utilizing a technique that is known as the kernel ..

Imaging mass spectrometry of elements in forensic cases by LA-ICP-MS

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was performed to map elements in thin formalin-fixed paraffin-embedded tissue sections of two forensic cases with firearm and electrocution injuries, respectively. In both cases, histological examination of the wounded tissue regions revealed the presence of exogenous aggregates that may be interpreted as metallic depositions. The use of imaging LA-ICP-MS allowed us to unambiguously determine the elemental composition of the observed aggregates assisting the pathologist in case assessments. To the best of our knowledge, we demonstrate for the first time the use of imaging LA-ICP-MS as a complementary tool for forensic pathologists and toxicologists in order to map the presence of metals and other elements in thin tissue sections of post-mortem cases