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Speculation can enhance adders performance by making carry predictions. It consists in replacing the arithmetic function with a faster, approximated, one, giving correct results most of the time. An error detection stage flags the misprediction events, in such cases, a two-cycles error correction stage is used, constituting a variable latency speculative adder. This paper proposes novel variable latency speculative adders based on Han-Carlson parallel-prefix topologies. The proposed adders are more effective than variable latency Kogge-Stone adders previously proposed in literature. A novel error detection technique that reduces error probability, compared to previous approaches, is proposed. Synthesis results, in the UMC 65nm library, show that proposed variable latency topologies outperform previously developed speculative Kogge-Stone adders and non-speculative ones, when high-speed is required. It is also shown that non-speculative adders remain the best choice when the speed constraint is relaxed

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Pyrrolizidine alkaloids (PAs) are secondary metabolites produced by over 6000 plant species worldwide. PAs enter the food chain through accidental co-harvesting of PA-containing weeds and through soil transfer from the living plant to surrounding acceptor plants. In animal studies, 1,2-unsaturated PAs have proven to be genotoxic carcinogens. According to the scientific opinion expressed by the 2017 EFSA, the foods with the highest levels of PA contamination were honey, tea, herbal infusions, and food supplements. Following the EFSA’s recommendations, data on the presence of PAs in relevant food were monitored and collected. On 1 July 2022, the Commission Regulation (EU) 2020/2040 came into force, repealed by Commission Regulation (EU) 2023/915, setting maximum levels for the sum of pyrrolizidine alkaloids in certain food. A total of 602 food samples were collected from the Italian market between 2019 and 2022 and were classified as honey, pollen, dried tea, dried herbal infusions, dried herbs, and fresh borage leaves. The food samples were analyzed for their PA content via an in-house LC-MS/MS method that can detect PAs according to Regulation 2023/915. Overall, 42% of the analyzed samples were PA-contaminated, 14% exceeded the EU limits, and the items most frequently contaminated included dried herbs and tea. In conclusion, the number of food items containing considerable amounts of PAs may cause concern because they may contribute to human exposure, especially considering vulnerable populations—most importantly, children and pregnant women.