A facile one‐pot regioselective synthesis of [1,2,4]triazolo[4,3‐a]5(1H)‐pyrimidinones via tandem Japp–Klingemann,Smiles rearrangement,and cyclization reactions

Coupling of active [(4‐oxo‐6‐phenyl‐3H‐pyrimidin‐2‐yl)thio]methine compounds ( 3 ) with diazotized anilines in the presence of base gave [1,2,4]triazolo[4,3‐a]pyrimidines ( 7 ). The latter products were also obtained by reactions of hydrazonoyl chlorides ( 10 ) with either 6‐phenyl‐2‐thiouracil ( 1 ) or the 2‐methylthio derivative 9 . The mechanisms and the regiochemistry of the reactions studied are discussed. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:136–140, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10008     

Green magnetic snail shell hydroxyapatite sorbent for reliable solid-phase extraction of pesticides from water samples

To address sustainability issues, the green synthesis of nanomaterials has recently received considerable attention. This article addresses a novel and cost-effective adsorbent for the extraction of eight phenyl-N-methylcarbamate insecticides from water samples. We first synthesized a magnetite/hydroxyapatite nanocomposite using snail shell powder via an environmental friendly approach. The morphology and physicochemical properties of magnetic hydroxyapatite were characterized by Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. Magnetic extraction parameters were optimized using a Doehlert matrix. Under optimum conditions, the magnetic extraction coupled with a LC–MS method shows good linearity with R² ≥ 0.9982, suitable intra- and interday precision, and limits of detection and quantification in the range of 0.052–0.093 μg/L and 0.11–0.31 μg/L, respectively. Satisfactory relative recoveries of all carbamates were achieved from fortified water samples in the range of 93.89–101.01%.     

Control of Quantum-Memory Induced by Generated Thermal XYZ-Heisenberg Entanglement: y-Component DM Interaction

This study explores the thermal quantum-memory-assisted entropic uncertainty relation (QM-EUR) and entanglement in a general two-qubit XYZ-Heisenberg spin chain model in the presence of the Dzyaloshinskii–Moriya (DM) interaction. The characterization of y-component DM and spin–spin interactions are particularly focused. It is found that the DM and spin–spin interaction strengths highly regulate the flow behavior and the initial final levels of QM-EUR and entanglement. In comparison, the spin–spin interaction strength in the z-direction remains useful in both ferromagnetic and anti-ferromagnetic regimes for entropic uncertainty suppression and entanglement generation. Additionally, the negative and the positive $y\mathrm{-}$directed DM values can usefully turn classical states into resourceful quantum states. The dynamics of thermal QM-EUR and entanglement-of-formation have symmetric behaviors only with respect to y-component DM and z-component spin–spin interaction. Finally, different critical points of temperature, $y\mathrm{-}$component DM as well as spin–spin interaction are encountered, which should be opted to preserve quantum correlations and degrade uncertainty.     

Endangered species,real options,and forest management

We use a real option approach to determine optimally when a social planner has to stop or resume logging in situations where an endangered species relies on forest habitat for its survival, and that habitat evolves stochasticly. The model incorporates economic, ecological and social features, and is calibrated to generate an optimal forest management rule that balances the benefits from commercial forest exploitation with the risks of extinction facing the endangered species. For the reasonable parameters used in our application to the Rangifer tarandus caribou, an endangered species in Central Labrador (Canada), the policy of banning logging temporarily is quite attractive as it does not require long banning periods while it drastically reduces the extinction risk and increases forest value. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)