1,617 research outputs found

    An improved geometric inequality via vanishing moments, with applications to singular Liouville equations

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    We consider a class of singular Liouville equations on compact surfaces motivated by the study of Electroweak and Self-Dual Chern-Simons theories, the Gaussian curvature prescription with conical singularities and Onsager's description of turbulence. We analyse the problem of existence variationally, and show how the angular distribution of the conformal volume near the singularities may lead to improvements in the Moser-Trudinger inequality, and in turn to lower bounds on the Euler-Lagrange functional. We then discuss existence and non-existence results.Comment: some references adde

    Snow cover monitoring by machine processing of multitemporal LANDSAT MSS data

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    LANDSAT frames were geometrically corrected and data sets from six different dates were overlaid to produce a 24 channel (six dates and four wavelength bands) data tape. Changes in the extent of the snowpack could be accurately and easily determined using a change detection technique on data which had previously been classified by the LARSYS software system. A second phase of the analysis involved determination of the relationship between spatial resolution or data sampling frequency and accuracy of measuring the area of the snowpack

    New Insights on the Effects of Methylphenidate in Attention Deficit Hyperactivity Disorder

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    This narrative review describes an overview of the multiple effects of methylphenidate (MPH) in attention-deficit/hyperactivity disorder (ADHD) and its potential neurobiological targets. It addressed the following aspects: 1) MPH effects on attention and executive functions in ADHD; 2) the relation between MPH efficacy and dopamine transporter gene (DAT) polymorphism; and 3) the role of MPH as an epigenetic modulator in ADHD. Literature analysis showed that MPH, the most commonly used psychostimulant in the therapy of ADHD, acts on multiple components of the disorder. Marked improvements in attentional and executive dysfunction have been observed in children with ADHD during treatment with MPH, as well as reductions in neurological soft signs. MPH efficacy may be influenced by polymorphisms in the DAT, and better responses to treatment were associated with the 10/10 genotype. Innovative lines of research have suggested that ADHD etiopathogenesis and its neuropsychological phenotypes also depend on the expression levels of human endogenous retrovirus (HERV). In particular, several studies have revealed that ADHD is associated with HERV-H over-expression and that MPH administration results in decreased expression levels of this retroviral family and a reduction in the main symptoms of the disorder. In conclusion, there is a confirmed role for MPH as an elective drug in the therapy of ADHD alone or in association with behavioral therapy. Its effectiveness can vary based on DAT polymorphisms and can act as a modulator of HERV-H gene expression, pointing to targets for a precision medicine approach

    DApps Ecosystems: Mapping the Network Structure of Smart Contract Interactions

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    Data availability - The datasets analysed during the current study can be retrieved using the tool presented in Smart contracts data of Dapps are publicly available from their respective Github repositories [https://github.com/DerwenAI/disparity_filter]. To support future work in this area, we have made our dataset publicly available via the Zenodo repository https://zenodo.org/records/12731531 and https://zenodo.org/records/13772792.Preprint available on arxiv - https://doi.org/10.48550/arXiv.2401.01991Decentralized applications (DApps) built on blockchain platforms such as Ethereum and coded in languages such as Solidity, have recently gained attention for their potential to disrupt traditional centralized systems. Despite their rapid adoption, limited research has been conducted to understand the underlying code structure of these applications. In particular, each DApp is composed of multiple smart contracts, each containing a number of functions that can be called to trigger a specific event, e.g., a token transfer. In this paper, we reconstruct and analyse the network of contracts and functions calls within the DApp, which is helpful to unveil vulnerabilities that can be exploited by malicious attackers. We show how decentralization is architecturally implemented, identifying common development patterns and anomalies that could influence the system’s robustness and efficiency. We find a consistent network structure characterized by modular, self-sufficient contracts and a complex web of function interactions, indicating common coding practices across the blockchain community. Critically, a small number of key functions within each DApp play a central role in maintaining network connectivity, making them potential targets for cyber attacks and highlighting the need for robust security measures.Ethereum foundation grant FY23-104

    Evaluation of Hydrogen Utilization for Catalytic Hydrodeoxygenation of Residual Biomass Pyrolysis Oil at Atmospheric Pressure

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    Biomass is an abundant renewable energy resource that can be converted into carbon-based biofuels. Pyrolysis is a thermochemical process that allows the rapid conversion of residual biomass and biowaste into bio-oil, a liquid biofuel with a high energy density. Hydrodeoxygenation (HDO) is a catalytic process in which typically high-pressure hydrogen is used to remove oxygen mainly through dehydration, decarboxylation and decarbonylation reactions from the oxygenated compounds of bio-oil. The objective of this work is to evaluate the process of hydrodeoxygenation under mild conditions, i.e. atmospheric pressure, quantifying the hydrogen consumption and the degree of deoxygenation. The organic fraction of the pyrolysis oil of spent coffee grounds has been processed in a packed-bed reactor in a semi-continuous regime. The performance of two different MoO3/NiO alumina-supported catalysts were evaluated at 350°C and LHSV of 0.5. The results showed a high upgraded oil yield (72-87 w/w %), limited gas production (up to 1 w/w%) and a limited coking (12-26 % w/w). GC-MS analysis of upgraded oil showed a significant reduction of hydrocarbons molecular weight, as well as caffeine, fatty acids and furans relative concentration, while pyridines, phenolics and ketones were still very abundant. The measured hydrogen consumption was very limited (up to 1g/L bio-oil), suggesting that increasing pressure would be beneficial for higher degree of deoxygenation

    Sustainability in Blockchain Development: A BERT-Based Analysis of Ethereum Developer Discussions

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    Blockchain technology faces significant challenges related to sustainability, including issues with optimisation, as well as high energy and gas consumption - factors that developers may sometimes neglect. We introduce a methodology to analyse the key sustainability topics discussed by Go-Ethereum developers, using thematic analysis of their issues and comments from Github. Our approach uses the BERT model to conduct an in-depth topic analysis, enabling us to study the underlying themes and trends in developer's conversations regarding energy use and sustainability. We assess the sustainability of the identified topics using the five dimensions outlined in the Sustainability Awareness Framework (SusAF): economic, social, individual, environmental, and technical. Our goal is to shed light on how much attention developers pay to sustainability and energy consumption issues. The findings from this qualitative analysis aim to encourage technologists to incorporate these considerations into their future projects, in order to achieve better outcomes in terms of sustainability and reduced consumption

    Chromosome numbers for the Italian flora: 2.

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    In this contribution new chromosome numbers for Italian endemic taxa are presented. It includes 13 chromosome counts for Ornithogalum (Asparagaceae), Anthemis, Carduus, Centaurea, Cirsium, Hieracium, Taraxacum (Asteraceae), Asyneuma (Campanulaceae), Knautia (Caprifoliaceae), Gypsophila (Caryophyllaceae), Linum (Linaceae), Helleborus (Ranunculaceae)
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