134 research outputs found

    Exploring the landscape of dismantling strategies based on the community structure of networks

    Get PDF
    Network dismantling is a relevant research area in network science, gathering attention both from a theoretical and an operational point of view. Here, we propose a general framework for dismantling that prioritizes the removal of nodes that bridge together different network communities. The strategies we detect are not unique, as they depend on the specific realization of the community detection algorithm considered. However, when applying the methodology to some synthetic benchmark and real-world networks we find that the dismantling performances are strongly robust, and do not depend on the specific algorithm. Thus, the stochasticity inherently present in many community detection algorithms allows to identify several strategies that have comparable effectiveness but require the removal of distinct subsets of nodes. This feature is highly relevant in operational contexts in which the removal of nodes is costly and allows to identify the least expensive strategy that still holds high effectiveness

    Economic sector identification in a set of stocks traded at the New York Stock Exchange: a comparative analysis

    Get PDF
    We review some methods recently used in the literature to detect the existence of a certain degree of common behavior of stock returns belonging to the same economic sector. Specifically, we discuss methods based on random matrix theory and hierarchical clustering techniques. We apply these methods to a set of stocks traded at the New York Stock Exchange. The investigated time series are recorded at a daily time horizon. All the considered methods are able to detect economic information and the presence of clusters characterized by the economic sector of stocks. However, different methodologies provide different information about the considered set. Our comparative analysis suggests that the application of just a single method could not be able to extract all the economic information present in the correlation coefficient matrix of a set of stocks.Comment: 13 pages, 8 figures, 2 Table

    Networks of equities in financial markets

    Full text link
    We review the recent approach of correlation based networks of financial equities. We investigate portfolio of stocks at different time horizons, financial indices and volatility time series and we show that meaningful economic information can be extracted from noise dressed correlation matrices. We show that the method can be used to falsify widespread market models by directly comparing the topological properties of networks of real and artificial markets.Comment: 9 pages, 8 figures. Accepted for publication in EPJ

    ComplexWorld Position Paper

    Get PDF
    The Complex ATM Position Paper is the common research vehicle that defines the high-level, strategic scientific vision for the ComplexWorld Network. The purpose of this document is to provide an orderly and consistent scientific framework for the WP-E complexity theme. The specific objectives of the position paper are to: - analyse the state of the art within the different research areas relevant to the network, identifying the major accomplishments and providing a comprehensive set of references, including the main publications and research projects; - include a complete list of , a list of application topics, and an analysis of which techniques are best suited to each one of those applications; - identify and perform an in-depth analysis of the most promising research avenues and the major research challenges lying at the junction of ATM and complex systems domains, with particular attention to their impact and potential benefits for the ATM community; - identify areas of common interest and synergies with other SESAR activities, with special attention to the research topics covered by other WP-E networks. An additional goal for future versions of this position paper is to develop an indicative roadmap on how these research challenges should be accomplished, providing a guide on how to leverage on different aspects of the complexity research in Air Transport

    Osteoradionecrosis of the jaws due to teeth extractions during and after radiotherapy: A systematic review

    Get PDF
    Teeth extractions before or after radiotherapy (RT) could be procedures at high risk for osteoradionecrosis (ORN) onset. This systematic review was performed to investigate the ORN incidence following teeth extractions during and after RT for head and neck (H&N) cancer and to evaluate any other possible risk factor. Methods: This systematic review was conducted according to PRISMA protocol, and the PROSPERO registration number was CRD42018079986. An electronic search was performed on the following search engines: PubMed, Scopus, and Web of Science. A cumulative meta‐analysis was performed. Results: Two thousand two hundred and eighty‐one records were screened, and nine were finally included. This systematic review revealed an ORN incidence of 5.8% (41 patients out of 462, 95% CI = 2.3–9.4); 3 ORN developed in the maxilla. No other clinical risk factors were detected. Conclusion: Post‐RT teeth extractions represent a major risk factor for ORN development, especially in the mandible, with a diminishing trend in the last years. Further research on other possible risk factors might improve this evidence

    The Harvesting Memories Project: Historical ecology and landscape changes of the Sicani Mountains in Sicily

    Get PDF
    The Harvesting Memories project aims to investigate the historical landscape dynamics in an inner area of the Sicani Mountains district in Western Sicily (Contrada Castro, Corleone-Palermo). The interdisciplinary approach of the project allowed us to combine and integrate methods from different disciplines such as historical ecology, landscape archaeology, archaeobotany and GIS-based spatial analysis. In this paper some results have been summarized. The comparison between land mosaic change during the last 60 years, the relationship between site catchment area and land suitability and the correlation between archaeobotanical and phytosociological data. This approach underlined the relevance of the historical ecology for understanding landscape trajectories and planning strategy of suitable development of rural areas

    Optimizing Femoral Access in Emergency EVAR with a Decision-Making Algorithm

    Get PDF
    Endovascular aneurysm repair (EVAR) has become the preferred approach over open repair for abdominal aortic aneurysms (AAAs) due to its minimally invasive nature. The common femoral artery (CFA) is the main access vessel for EVAR, with both surgical exposure and percutaneous access being utilized. However, in emergent cases, percutaneous access can be challenging and may result in complications such as bleeding or dissection thrombosis, leading to the need for surgical conversion. This study aimed to share experiences in implementing a decision-making algorithm to reduce surgical conversions due to percutaneous access failures. A total of 74 aortic patients treated with EVAR in emergency settings were included in this retrospective study. This study focused on various outcomes such as perioperative mortality, morbidity, procedure time, surgical exposure time, and surgical conversion rate. After the implementation of the decision-making algorithm, decreases in surgical conversions and operating time were observed. Percutaneous access was found to be more challenging in cases with specific anatomical characteristics of the CFA, such as severe atherosclerosis or smaller vessel diameter. This study highlighted the importance of carefully assessing patient anatomical features and utilizing a decision-making algorithm to optimize outcomes in EVAR procedures. Further research is needed to continue improving practices for managing aortic aneurysms and reducing complications in femoral artery access approaches

    Preliminary finite element analysis of the stainless-steel liner of the maintainable test cell concept of IFMIF-DONES

    Get PDF
    The main purpose of IFMIF-DONES facility is to provide a neutron source for irradiating small specimens and producing experimental data of material properties for the construction of DEMO fusion power plant. The Test Cell (TC) of the DONES is a confined and well-shielded room, where the strong irradiation environment is created. The biological shielding of the TC mainly consists of several meters thick concrete walls and shielding plugs, and a stainless-steel liner. The TC liner and the concrete walls are actively cooled by water because of the high volumetric heating coming from nuclear reactions. Although, the TC is designed to be fully functional for the complete life span of the facility, still there is a very low probability of defect of the TC biological shielding due to their exposure of intense neutron and gamma irradiation. Therefore, the original TC configuration, which was a monolithic approach, had to be revised. Due to this reason, at the end of 2019 the project team has changed the TC concept from the monolithic design to the so-called Maintainable TC Concept (MTCC) design, which allows a maintenance possibility in case of unexpected damage
    corecore