Do Global CO2 Emissions from Fossil-Fuel Consumption Exhibit Long Memory? A Fractional Integration Analysis

In this article we use an autoregressive fractionally integrated moving average approach to measure the degree of fractional integration of aggregate world CO2 emissions and its five components – coal, oil, gas, cement, and gas flaring. We find that all variables are stationary and mean reverting, but exhibit long-term memory. Our results suggest that both coal and oil combustion emissions have the weakest degree of long-range dependence, while emissions from gas and gas flaring have the strongest. With evidence of long memory, we conclude that transitory policy shocks are likely to have long-lasting effects, but not permanent effects. Accordingly, permanent effects on CO2 emissions require a more permanent policy stance. In this context, if one were to rely only on testing for stationarity and non-stationarity, one would likely conclude in favour of non-stationarity, and therefore that even transitory policy shocks

Dual layer solid phase extraction based on molecular imprinting technology: Seeking a route to enhance selectivity for trace analysis of pesticide residues in olive oil.

Aiming to introduce a multiresidue analysis for the trace detection of pesticide residues belonging to organophosphorus and triazine classes from olive oil samples, a new sample preparation methodology comprising the use of a dual layer of “tailor-made” molecularly imprinted polymers (MIPs) SPE for the simultaneous extraction of both pesticides in a single procedure has been attempted. This work has focused on the implementation of a dual MIP-layer SPE procedure (DL-MISPE) encompassing the use of two MIP layers as specific sorbents. In order to achieve higher recovery rates, the amount of MIP layers has been optimized as well as the influence of MIP packaging order. The optimized DL-MISPE approach has been used in the preconcentration of spiked organic olive oil samples with concentrations of dimethoate and terbuthylazine similar to the maximum residue limits and further quantification by HPLC. High recovery rates for dimethoate (95%) and terbuthylazine (94%) have been achieved with good accuracy and precision. Overall, this work constitutes the first attempt on the development of a dual pesticide residue methodology for the trace analysis of pesticide residues based on molecular imprinting technology. Thus, DL-MISPE constitutes a reliable, robust, and sensitive sample preparation methodology that enables preconcentration of the target pesticides in complex olive oil samples, even at levels similar to the maximum residue limits enforced by the legislation.