Micro-level reserving for general insurance claims using a long short-term memory network

Detailed information about individual claims are completely ignored when insurance claims data are aggregated and structured in development triangles for loss reserving. In the hope of extracting predictive power from the individual claims characteristics, researchers have recently proposed to use micro-level loss reserving approaches. We introduce a discrete-time individual reserving framework incorporating granular information in a deep learning approach named Long Short-Term Memory (LSTM) neural network. At each time period, the network has two tasks: first, classifying whether there is a payment or a recovery, and second, predicting the corresponding non-zero amount, if any. Based on a generalized Pareto model for excess payments over a threshold, we adjust the LSTM reserve prediction to account for extreme payments. We illustrate the estimation procedure on a simulated and a real general insurance dataset. We compare our approach with the chain-ladder aggregate method using the predictive outstanding loss estimates and their actual values.     

Dye-sensitized photooxygenation of the C=N bond. 5. substituent effects on the cleavage of the C=N bond of C-aryl-N-aryl-N-methylhydrazones

The title compounds are cleaved cleanly at the C=N bond by singlet oxygen ((1)O(2), (1)Delta(g)) yielding arylaldehydes and N-aryl-N-methylnitrosamines. These reactions take place more rapidly at -78 degrees C than at room temperature. The effects of substituent variation at both the C-aryl and N-aryl groups were studied using a competitive method. Good correlations of the resulting rate ratios with substituent constants (sigma(-) or sigma(+)) were obtained yielding small to very small rho values indicative of small to very small changes in charge distribution between the reactant and the rate determining transition state. Electron withdrawing groups on the C-aryl moiety retard reaction somewhat by preferential stabilization of the hydrazone. Electron donors on the other hand slightly stabilize the rate determining transition state. Substituents on the N-aryl group have almost no effect. Inhibition by 3,5-di-tert-butylphenol was not observed showing that free (uncaged) radical intermediates are not involved in the mechanism. We postulate a mechanism in which the initial event is exothermic electron transfer from the hydrazone to (1)O(2) leading to an ion-radical caged pair. Subsequent covalent bond formation between the hydrazone carbon and an oxygen atom is rate controlling. The transition state for this step also has a lower enthalpy than the starting reactants, but the free energy of activation is dominated by a large negative TDeltaS++term leading to the negative temperature dependence. Direct formation of a C-O bond in the initial step is not unambiguously ruled out. Subsequent steps lead to C-N cleavage.     

Two new triterpene saponins from Eryngium campestre

Two new triterpene saponins, 3-O-beta-D-glucopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucuronopyranosyl-22-O-angeloyl-R1-barrigenol (1) and 3-O-beta-D-glucopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucuronopyranosyl-22-O-beta,beta-dimethylacryloyl-A1-barrigenol (2), were isolated from the roots of Eryngium campestre (Apiaceae). Their structures were established mainly by 2D NMR techniques and mass spectrometry.     

Anatolioside E: A New Acyclic Monoterpene Glycoside from Viburnum orientale

A new open-chain monoterpene glycoside, anatolioside E ( 1 ), was isolated from the leaves of Viburnum orientale in addition to three known acyclic monoterpene glycosides, betulalbusides A ( 2 ) and B ( 3 ), and 2(E)-2,6-dimethyl-2,7-octadien-1,6-diol-6-O-β-D -glucopyranoside( 4 ). The structure of anatolioside E ( 1 ) was elucidated on the basis of chemical and spectral data as 6-O-[β-D -glucopyransoyl-(1?? → 6?″)-2-(E), 6(R), 2,6-dimethyl-6-hydroxy-2,7-octadienoyl-(1?″ → 2″″)-β-D -glucopyranosyl-(1″″ → 6?)-2-(E), 6(R), 2,6-dimethyl-6-hydroxy-2,7-octadienoyl-(1? → 4″)-α-L -rhamnopyranosyl-(1″″ → 2′)-β-D -glucopyranosyl]linalool.     

Photoelectron spectra of bicyclic peroxides

The He(I) photoelectron spectra of nine bicyclic alkyl peroxide have been recorded. The first peaks are assigned by comparison with results of a MINDO/3 calculation. A correlation between the split of the first two ionization potentials and the OO torsional angle Θ is found.     

Singlet oxygenation of cycloocta-1,3,5-triene: Formation of (4.2.2)- and (2.2.2)- cycloadducts.

Photosensitized singlet oxygenation of 1,3,5-cyclooctatriene affords the (4.2.2)- and (2.2.2)-type endoperoxides, which were reduced with diimide, thermally isomerized, and deoxygenated with triphenylphosphine.