Archivio Istituzionale della Ricerca- Università del Salento
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Emperor Julian, Paul of Tarsus, and the Octopus
Full text linkThe so-called “octopus norm” was originally described by Pindar and Theognis. It represented the way in which a poet could adapt to contingent circumstances without abdicating his own sensibility, grasping what might be appropriate to say or not to say in relation to a specific audience or context. This contribution considers two occurrences of this so-called norm in the works of the Emperor Julian, revealing a polemical use of the image of the octopus. This study primarily attempts to contextualize the two Julian passages, highlighting their sources, and to clarify the polemical value of his use of the “octopus norm”, which is very different from the virtuous manner suggested by the archaic poets
Third-party intervention to address gender microaggressions among college students: The role of system justification beliefs and contact with counter-stereotypical women
Full text linkEffect of PET Micro/Nanoplastics on Model Freshwater Zooplankton
Full text linkMicro- and nanoplastic pollutants are among the major environmental challenges, and are exacerbated by the continuous degradation of growing amounts of plastic debris in the aquatic environment. The purpose of this study was to investigate the morphology of micro/nanoplastics (M/NPs) formed from polyethylene terephthalate (PET) by mechanical degradation in an aquatic environment, which mimics the processes in the natural environment well, and to determine the impact of these particles on model aquatic organisms. To this end, M/NPs were obtained by ball milling in an aqueous medium and the effect of milling length on particle size and shape was investigated. The particles obtained in an environment simulating natural conditions were irregularly shaped, and those of nanometric size tended to form aggregates of various shapes. The ingestion and toxicity of PET M/NPs to freshwater zooplankton were then assessed. Daphnia magna and Thamnocephalus platyurus were used in a series of acute ecotoxicity tests, by exposure to M/NP dispersions at environmentally realistic concentrations (0.01–1.0 mg/L), as well as at very high concentrations (100–1000 mg/L). A significant uptake of PET particles by both types of invertebrates was observed, and the M/NPs were mainly concentrated in the digestive tracts of the crustaceans. However, they did not cause acute toxicity to the tested organisms or a reduction in their swimming activity, even at concentrations as high as 1000 mg/L
Covariance models through difference between Matérn families
No full textIt is well known that Whittle–Matérn family represents one of the most utilized class of covariance functions because of some special features which are capable to describe several correlation structures. However, one of the main drawbacks of this last family concerns its failure to model negative correlation structures. In this paper, utilizing the Whittle–Matérn family, new classes of covariance models, suitable to model negative correlations, have been presented and their properties have been analyzed. The new families are flexible enough because they allow to choose covariance models which always present positive values in their domain, as well as covariance models which are negative in a subset of their domain. On the other hand, all the traditional hole effect models, proposed in the literature, essentially stem from the Bessel family and they are characterized by the same features, i.e., they present a countable infinity of zeros and a parabolic behaviour near the origin. Conversely, the models proposed in this paper are characterized by a complementary behaviour, which cannot be detailed by all the classical hole effect correlation models: they are essentially characterized by just one zero, moreover they are able to describe various behaviours near the origin (linear and parabolic), as well as different behaviours concerning the concavity in proximity of the origin (upwards and downwards). In summary, they can describe correlation structures which cannot be detailed by the Whittle–Matérn family
High latitude observation of the Forbush decrease during the May 2024 solar storms with muon and neutron detectors on Svalbard
No full textDuring the series of intense solar flares and coronal mass ejections, that occurred in May 2024, a remarkable Forbush decrease in the cosmic ray flux was observed on the Earth. While this event was observed by particle detectors around the world, the archipelago of Svalbard was heavily exposed to it due to the weak geomagnetic shielding in the polar region. In this study, an analysis of the Forbush decrease event was carried out with a unique combination of muon and neutron detectors on Svalbard: at Ny-Ålesund three scintillator-based muon telescopes of the Extreme Energy Events (EEE) project, 14 channels of a Bonner Sphere neutron Spectrometer (BSS), and thermal and epithermal neutron sensors used for hydrological monitoring; and, at Barentsburg, a high-energy neutron monitor operated by the Polar Geophysical Institute. Most sensors showed significant responses and correlation during the event. The observed relative magnitude of the Forbush decrease was found to depend on the detector's energy sensitivity and was ≈9% for thermal neutrons, ≈8% for high-energy neutrons, and ≈3% for muons. The uncertainty of these results strongly depends on factors like the count rate, which ranged from 101 to 105 cph and resulted in a low signal-to-noise ratio particularly for the BSS. These multi-particle and multi-energy observations provide an unprecendented view on the Earth's exposure to cosmic rays during solar events
Analysis and Simulation of Fuel Consumption and Emissions in a Heavy-Duty Diesel Truck under Real-world Driving Conditions for Hybridization and Waste Heat Recovery
No full textHeavy-duty vehicles contribute significantly to global greenhouse gas emissions and are now facing challenges in meeting emission regulatory standards, particularly cold-start operations. These challenges are particularly significant during transient operations, where fuel efficiency drops and emissions peak due to suboptimal thermal conditions. Advanced powertrains that use hybridization and waste heat recovery with phase-changing materials offer potential pathways to mitigate fuel consumption and emissions under real-world driving conditions. Still, they need to be accurately sized, and the energy flows handled to overcome the disadvantages of increased mass and complexity. This investigation lays the groundwork for the development of advanced power systems by implementing a scalable, map-based model for heavy-duty diesel engines. The model is validated using an open-access dataset related to a heavy-duty vehicle equipped with a 6-cylinder diesel engine, which performed 28 different trips on the same route with the same driver. The trips are executed with three different payload values and contain both cold-start and hot-start operating conditions. The validation is based on quasi-static modeling of the vehicle powertrain. The proposed model can accurately predict fuel consumption and CO2 emissions for all trips, with an average relative error of 2.4%. The results of the investigation also include preliminary sizing and analysis of a hybrid electric configuration that exploits the synergy between hybridization and waste heat recovery. In comparison to the original powertrain, the proposed powertrain resulted in a roughly 15% reduction in fuel consumption and a 37.5% increase in exhaust temperature. These findings demonstrate the potential for integrated hybrid and waste heat recovery systems to enhance fuel economy in heavy-duty transportation while supporting compliance with emission regulations
Shill Bidding Prevention in Decentralized Auctions Using Smart Contracts
No full textIn online auctions, fraudulent behaviors such as shill bidding pose significant risks. This paper presents a conceptual framework that applies dynamic, behavior-based penalties to deter auction fraud using blockchain smart contracts. Unlike traditional post-auction detection methods, this approach prevents manipulation in real-time by introducing an economic disincentive system where penalty severity scales with suspicious bidding patterns. The framework employs the proposed Bid Shill Score (BSS) to evaluate nine distinct bidding behaviors, dynamically adjusting the penalty fees to make fraudulent activity financially unaffordable while providing fair competition.
The system is implemented within a decentralized English auction on the Ethereum blockchain, demonstrating how smart contracts enforce transparent auction rules without trusted intermediaries. Simulations confirm the effectiveness of the proposed model: the dynamic penalty mechanism reduces the profitability of shill bidding while keeping penalties low for honest bidders. Performance evaluation shows that the system introduces only moderate gas and latency overhead, keeping transaction costs and response times within practical bounds for real-world use. The approach provides a practical method for behaviour-based fraud prevention in decentralised systems where trust cannot be assumed
Assessing sustainability of smart last mile delivery: a simulation-based decision support tool
Full text linkThe increasing demand of e-commerce is forcing economic and environmental inefficiency in last mile logistics (LML). The adoption of smart and autonomous technologies, such as Unmanned Aerial Vehicles (UAVs) and Autonomous Delivery Robots (ADRs), is being evaluated in LML in order to increase its effectiveness. UAVs offer advantages such as faster delivery times and reduced traffic congestion, but face challenges like weather sensitivity and the need for dedicated take-off and landing infrastructure. ADRs can reduce emissions and operational costs compared to traditional LML systems, but their full application is limited mainly due to slower speeds and complex interactions with pedestrians. Despite their limitations, in future years these technologies could be fully applied for LML: thus, evaluating their environmental impact during LML service is necessary to plan their full-scale application. This study proposes a simulation-based decision support tool for assessing the performance of traditional and smart LML technologies according to economic and environmental points of view. By leveraging advanced simulation models, the proposed tool allows to estimate these impacts under varying operational conditions, providing a comprehensive framework for decision-making the LML field by comparing traditional versus innovative LML services. The tool was validated through a case study application in an urban context, demonstrating its ability to highlight the potential benefits and challenges of applying UAVs and ADRs into LML networks. Results indicate that unmanned delivery vehicles allow for a substantial reduction in carbon emissions in the operational phase, confirming their potential as a more environmentally sustainable solution for urban last mile logistics. In addition, the total cost associated with unmanned systems is found to be comparable to that of conventional vehicles, particularly when these latter operate under medium-to-high traffic conditions. Researchers and logistic companies can use this tool to evaluate and optimize the impact of their innovative LML services strategies and achieve improved economic and environmental sustainability levels