201 research outputs found

    Two boundary integral equation methods for linear elastodynamics problems on unbounded domains

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    We consider (transient) 3D elastic wave propagation problems in unbounded isotropic homogeneous media, which can be reduced to corresponding 2D ones. For their solution, we propose and compare two boundary integral equation approaches, both based on the coupling of a discrete time convolution quadrature with a classical space collocation discretization. In the first approach, the PDE problem is preliminary replaced by the equivalent well known (vector) space-time boundary integral equation formulation, while in the second, the same PDE is replaced by a system of two (coupled) wave equations, each one of which is then represented by the associated boundary integral equation. The construction of these two approaches is described and discussed. Some numerical testing are also presented

    Bayesian Approaches to Learning from Data how to Untangle the Travel Behavior and Land Use Relationships

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    The body of research on land use and travel behavior relationships reaches widely different conclusions with results varying even when considering a single author. The hypothesis of this research is that these differences arise, in part, from the fact that the vast majority of these studies do not address all the theoretical travel behavior tenets and are therefore ad-hoc in nature. An inductive approach to the study of the relationships between land use and travel behavior, prior to carrying out traditional deductive studies, can help improve the outcomes by providing an opportunity to identify and test such relationships. With data sourced from the 2001 National Household Travel Survey Add-On, supplemented with local land use data, this study uses heuristic search algorithms to evaluate relationships hidden in the data without these being framed, a priori, by specific statistical constructs. Bayesian scoring is used to evaluate and compare the results from actual data collected for the Baltimore Metropolitan Area with the set of predominant conceptual frameworks linking travel behavior and land use obtained from the literature. Results show that socioeconomic factors and land use characteristics act in a nested fashion, one in which socioeconomic factors do not influence travel behavior independently of land use characteristics. The land use travel behavior connection is specifically strong only for particular combinations of socioeconomic characteristics and a land use mix which includes both moderate residential densities and a significant amount of commercial opportunities. The study also finds that the heuristic search approach to derive relationships between land use and travel behavior does work, that this technique needs to be fine tuned for the proper use of spatially explicit data, and that although the research outputs are an unbiased representation of the land use travel behavior relationships, they need proper interpretation, especially in light of persisting theoretical questions still driving this research field. The study concludes that an inductive approach to the analysis of the relationships between land use and travel behavior provides valuable knowledge of the data that can be used to better formulate deductive studies, so that the two methodologies are complementary to each other

    Climate change multi-risk assessment for mango cultivation in Sicily, Italy by using bayesian network

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    Ensuring food security poses a significant challenge for organizations and consultant companies involved in the agriculture industry or responsible for food programs. This challenge is particularly relevant in Sicily, Italy, which has a semi-tropical climate. Given the favorable weather conditions for mango cultivation and other tropical crops, it becomes crucial to consider measures for safeguarding against potential climate change impacts in the future. Climate change is expected to bring changes and increased risks in terms of temperature, extreme events, soil salinity, and irregular rainfall. Amidst this looming threat, there is a growing demand for a fresh approach and supportive tools to manage risks and mitigate potential damages in policy-making and decision-making circles. In this study, we employ a robust method known as Bayesian Network (BN) to effectively capture and model multiple risks under various future scenarios. By exploring 'what-if' situations, such as the maximum levels of climate-related variables, the projected BN model is trained and validated using spatially-resolved data from the Messina region in Sicily. This approach enables us to understand the dynamic variations in localscale temperature and precipitation, as well as the underlying driving forces, within the timeframe of 2009-2022. The outputs of the Bayesian Network aid in predicting future trends in temperature and precipitation levels, thereby supporting the prioritization of mango cultivation and conservation efforts. In general, the findings derived from the BN analysis provide valuable support for disaster risk management and mitigation strategies in the face of climate change and extreme events. This tool can further enhance decision-making processes by integrating the spatial results of the developed model into a user-friendly interface such as Geographic Information System (GIS), thereby assisting policymakers and decision-makers in prioritizing Disaster Risk Management and Climate Change Adaptation plans

    Hemorrhage from primitive rectal varices in patient with idiophatic thrombosis of portal vein: case report

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    Introduction. Rectal varices, primitive or secondary to hypertensive or thrombotic disorders of mesenteric-portal circle, represent an uncommon cause of lower digestive bleeding. The presence of rectal varices associated to idiopathic venous portal thrombosis represents a distinct nosologic entity, with important clinical and therapeutic problems related to it. Case report. Patient of young age, with positive anamnesis for primitive rectal varicies, admitted to our department for a serious rettorragy. The laboratory underlined moderate anaemia and the endoscopy documented the presence of multiple rectal varices, without evident signs of bleeding; the endoscopy documented the presence of two esophageal small varicose cords F1. The hepatobiliary sonography and the portography showed the massive thrombosis of the portal vein. The new serious episode of rectal bleeding induced us to subject the patient to a surgical operation of Hartmann recto-sigmoid resection. Conclusion. Because of the slight number of reported cases of primitive rectal varices and because of the scattering of many dates it’s difficult to draw an univocal diagnostic and therapeutic algorithm. Clinical framing and subsequent therapeutic approach rise often up from personal experience rather than well defined guidelines. The treatment is controversial, time by time many therapeutic options are reported either conservative or interventist. The failure of conservative therapy and the recurrent episodes of bleeding give indication to surgical treatment, that is represented by Hartmann colonic resection and/or the porto-systemic shunts in the cases of portal hypertension; in our case we made colonic resection sec. because of lapsed performing status of the patient

    A Possible Circular Approach for Social Perception of Climate Adaptation Action Planning in Metropolitan Cities

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    AbstractOne of the factors that will affect the livability of cities and the overall citizens' quality of life in the future is certainly climate change. Urban areas will play a fundamental role in the commitment against climate change and will have to develop appropriate adaptation actions, in accordance with the European Strategy against climate change, including the planning and implementation of Green Infrastructures (GIs). They produce various environmental and social benefits in the urban context. Various studies have shown that citizenship involvement at all levels is necessary for the evaluation of the sharing of the proposed projects. The research proposes an innovative methodological model to support administrations in the strategic planning choice of GIs according to a shared and circular approach. To perform a multi-layer assessment, the multi-criteria evaluation will be combined with the circular evaluation model called Green City Circle. The evaluation is set up as a circular process, followed by a first investigative phase, followed by a proactive phase of solutions and an implementation phase up to a final stage of evaluation of the results and strategies for long-term sustainability. The study was carried out in the city of Catania to test a planning and management tool for GIs envisaged by the administration as win–win climate adaptation measures

    Flow cytofluorimetric analysis of anti-LRP4 (LDL receptor-related protein 4) autoantibodies in Italian patients with Myasthenia gravis

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    Background: Myasthenia gravis (MG) is an autoimmune disease in which 90% of patients have autoanti-bodies against the muscle nicotinic acetylcholine receptor (AChR), while autoantibodies to muscle-specific tyrosine kinase (MuSK) have been detected in half (5%) of the remaining 10%. Recently, the low-density lipoprotein receptor-related protein 4(LRP4), identified as the agrin receptor, has been recognized as a third autoimmune target in a significant portion of the double sero-negative (dSN) myasthenic individuals, with variable frequency depending on different methods and origin countries of the tested population. There is also convincing experimental evidence that anti-LRP4 autoantibodies may cause MG. Methods: The aim of this study was to test the presence and diagnostic significance of anti-LRP4 autoantibodies in an Italian population of 101 myasthenic patients (55 dSN, 23 AChR positive and 23 MuSK positive), 45 healthy blood donors and 40 patients with other neurological diseases as controls. All sera were analyzed by a cell-based antigen assay employing LRP4-transfected HEK293T cells, along with a flow cytofluorimetric detection system. Results: We found a 14.5% (8/55) frequency of positivity in the dSN-MG group and a 13% frequency of co-occurrence (3/23) in both AChR and MuSK positive patients; moreover, we report a younger female prevalence with a mild form of disease in LRP4-positive dSN-MG individuals. Conclusion: Our data confirm LRP4 as a new autoimmune target, supporting the value of including anti-LRP4 antibodies in further studies on Myasthenia gravis

    Crosslinked Hyaluronic Acid with Liposomes and Crocin Confers Cytoprotection in an Experimental Model of Dry Eye

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    Dry eye disease (DED) is a multifactorial condition caused by tear deficiency and accompanied by ocular surface damage. Recent data support a key role of oxidative and inflammatory processes in the pathogenesis of DED. Hyaluronic acid (HA) is widely used in artificial tears to treat DED by improving ocular hydration and reducing surface friction. Crocin (Cr), the main constituent of saffron, is a renowned compound that exhibits potent antioxidant and anti-inflammatory effects. The present study was undertaken to assess the viscosity and muco-adhesiveness of a photoactivated formulation with crosslinked HA (cHA), Cr, and liposomes (cHA-Cr-L). Our aim was also to evaluate whether cHA-Cr-L may exert cytoprotective effects against oxidative and inflammatory processes in human corneal epithelial cells (HCECs). Viscosity was measured using a rotational rheometer, and then the muco-adhesiveness was evaluated. Under hyperosmolarity (450 mOsm), the HCECs were treated with cHA-Cr-L. Interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha) were quantified by quantitative real-time polymerase chain reaction (RT-qPCR). The levels of reactive oxygen species (ROS) were measured using the DCF assay. The combined action of cHA-Cr-L produced a higher viscosity and muco-adhesiveness compared to the control. The anti-inflammatory effect of cHA-Cr-L was achieved through a significant reduction of IL-1beta and TNFalpha (p < 0.001). The results also showed that cHA-Cr-L reduces ROS production under conditions of hyperosmolarity (p < 0.001). We conclude that cHA-Cr-L has potential as a therapeutic agent in DED, which should be further investigated

    Neofusicoccum parvum causes stem canker of thornless blackberry in Italy

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    Important damage caused by the fungus Neofusicoccum parvum in thornless blackberry in southern Italy is reported for the first time. The most noticeable symptoms were stem cankers and yellowing of the foliage. Cankers on stems were initially elongated, and infected tissue was darkly pigmented. The fungus was identified based on morphological characteristics and by sequencing the ITS1-5.8S-ITS2 region and part of the translation elongation factor 1-alpha (EF1-a) gene. Pathogenicity tests confirmed that N. parvum caused the disease on blackberry, inducing symptoms similar to those occurring under natural conditions. This is potentially a serious disease of blackberry in southern Italy, where cultivation is expanding
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