125 research outputs found

    Stability assessment of enzyme stabilized road embankments

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    Road infrastructure is one of the most important factors for a country's development. The vital role that they play in the present economy is reflected in many kilometres of roads worldwide. The external loads due to recurring traffic loads and geohazards can result in road failures with consequences in terms of economic loss to asset managers, public safety and vehicle damage. Due to such adverse effects of road failures, soil stabilization is being widely used as a preventive measure of road failures since recently. However, the assessment (or design) of stabilized road embankments using current standards assume linear material response and two-dimensional geometric idealization. Such assumptions can lead to non-conservative results, leading the road embankments to fail in long-term mainly due to improper assessments in the designs. The current research investigates the assessment of enzyme based stabilized road embankments under external traffic loads using three-dimensional (3-D) finite element (FE) analysis. Firstly, laboratory tests were conducted to characterize the soil/stabilized soil and to calibrate the numerical models. Then, a series of FE analyses were conducted to investigate the performance of stabilized road embankments under external traffic loads. Results showed that the prediction of required pavement thicknesses using elasto-plastic 3-D modelling could be substantially different in comparison to the results obtained from available standard pavement design tools and 2-D idealization of pavement modelling. The study revealed the importance of considering realistic material performance and load applications during the assessment of pavement design in order to maximize the benefits of enzyme stabilization that can be effective in prevention of the road embankment failures

    Organised crime and international aid subversion: evidence from Colombia and Afghanistan

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    Scholarly attempts to explain aid subversion in post-conflict contexts frame the challenge in terms of corrupt practices and transactions disconnected from local power struggles. Also, they assume a distinction between organised crime and the state. This comparative analysis of aid subversion in Colombia and Afghanistan reveals the limits of such an approach. Focusing on relations that anchor organised crime within local political, social and economic processes, we demonstrate that organised crime is dynamic, driven by multiple motives, and endogenous to local power politics. Better understanding of governance arrangements around the organised crime-conflict nexus which enable aid subversion is therefore required

    Clinical characteristics and outcomes of incidental venous thromboembolism in cancer patients: insights from the Caravaggio study

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    Background Clinical guidelines advise similar anticoagulant treatment for symptomatic and incidental cancer-associated venous thromboembolism (VTE). We investigated clinical features and outcomes of cancer patients with incidental or symptomatic VTE randomized in the Caravaggio study. Objectives We performed a predefined sub-analysis of the Caravaggio study in order to investigate the clinical features and outcomes of incidental and symptomatic VTE in patients with cancer. The relative efficacy and safety of apixaban and dalteparin in patients with incidental and symptomatic VTE was also assessed. Methods The Caravaggio study compared apixaban to dalteparin for the 6-month treatment of cancer-associated VTE. The primary efficacy and safety outcomes were recurrent VTE and major bleeding. Results Two hundred thirty patients (20%) had incidental and 925 (80%) symptomatic VTE. Pulmonary embolism with or without deep vein thrombosis as index event, colorectal cancer, Eastern Cooperative Oncology Group (ECOG) score of 0, and locally advanced or metastatic cancer were more frequent in patients with incidental VTE. Deep vein thrombosis as index event, hematological cancer, and ECOG score of 2 were more frequent in patients with symptomatic VTE. Ten patients (4.3%) with incidental and 68 (7.4%) with symptomatic VTE had recurrent VTE (hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.29-1.10). Major bleeding occurred in 12 (5.2%) patients with incidental VTE and in 33 (3.6%) patients with symptomatic VTE (HR 1.43, 95% CI 0.74-2.77). When comparing apixaban to dalteparin in patients with symptomatic and incidental VTE, the HR for recurrence was 0.73 (95% CI 0.45-1.19) and 0.41 (95% CI 0.11-1.56), respectively, and the HR for major bleeding 0.93 (95% CI 0.47-1.83) and 0.96 (95% CI 0.31-2.96), respectively. Conclusions Compared to cancer patients with symptomatic VTE, those with incidental VTE have different clinical features at presentation, with a numerically lower incidence of recurrent VTE and a numerically higher incidence of major bleeding.Thrombosis and Hemostasi

    Sustainability of bridge maintenance

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    Bridge maintenance activities are important to consider within sustainable development due to the cost and environmental impact associated with various maintenance activities. Comparisons have been made between different bridge structural forms, based on materials, components and construction method, but less information is available on bridge maintenance activities to help decide a sustainable structural form. Typical maintenance aspects of the predominant forms of bridge structure (i.e. concrete, steel and masonry bridges) were considered in this study to reveal their sustainability in terms of materials, energy, transportation, human health and ecosystems. The results indicate that concrete and steel bridge maintenance activities have an average impact of 42% and 46% compared with 12% for masonry bridge maintenance activities. It is concluded that the component parts of concrete and steel bridges should be revised as they play an integral role in the selection of maintenance options

    High tie versus low tie of the inferior mesenteric artery: a protocol for a systematic review

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    In anterior resection of rectum, the section level of inferior mesenteric artery is still subject of controversy between the advocates of high and low tie. The low tie is the division and ligation to the branching of the left colic artery and the high tie is the division and ligation at its origin at the aorta. We intend to assess current scientific evidence in literature and to establish the differences comparing technique, anatomy and physiology. The aim of this protocol is to achieve a meta-analysis that tests safety and feasibility of the two procedures with several types of outcome measures

    Recurrent Ischemic Stroke and Bleeding in Patients With Atrial Fibrillation Who Suffered an Acute Stroke While on Treatment With Nonvitamin K Antagonist Oral Anticoagulants: The RENO-EXTEND Study

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    Background: In patients with atrial fibrillation who suffered an ischemic stroke while on treatment with nonvitamin K antagonist oral anticoagulants, rates and determinants of recurrent ischemic events and major bleedings remain uncertain. Methods: This prospective multicenter observational study aimed to estimate the rates of ischemic and bleeding events and their determinants in the follow-up of consecutive patients with atrial fibrillation who suffered an acute cerebrovascular ischemic event while on nonvitamin K antagonist oral anticoagulant treatment. Afterwards, we compared the estimated risks of ischemic and bleeding events between the patients in whom anticoagulant therapy was changed to those who continued the original treatment. Results: After a mean follow-up time of 15.0±10.9 months, 192 out of 1240 patients (15.5%) had 207 ischemic or bleeding events corresponding to an annual rate of 13.4%. Among the events, 111 were ischemic strokes, 15 systemic embolisms, 24 intracranial bleedings, and 57 major extracranial bleedings. Predictive factors of recurrent ischemic events (strokes and systemic embolisms) included CHA2DS2-VASc score after the index event (odds ratio [OR], 1.2 [95% CI, 1.0–1.3] for each point increase; P=0.05) and hypertension (OR, 2.3 [95% CI, 1.0–5.1]; P=0.04). Predictive factors of bleeding events (intracranial and major extracranial bleedings) included age (OR, 1.1 [95% CI, 1.0–1.2] for each year increase; P=0.002), history of major bleeding (OR, 6.9 [95% CI, 3.4–14.2]; P=0.0001) and the concomitant administration of an antiplatelet agent (OR, 2.8 [95% CI, 1.4–5.5]; P=0.003). Rates of ischemic and bleeding events were no different in patients who changed or not changed the original nonvitamin K antagonist oral anticoagulants treatment (OR, 1.2 [95% CI, 0.8–1.7]). Conclusions: Patients suffering a stroke despite being on nonvitamin K antagonist oral anticoagulant therapy are at high risk of recurrent ischemic stroke and bleeding. In these patients, further research is needed to improve secondary prevention by investigating the mechanisms of recurrent ischemic stroke and bleeding

    Power balances, transnational elites, and local economic governance: The political economy of development in MedellĂ­n

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    Applying a non-linear political economy analysis of power balances, institutional mechanisms, and elite structures, this study sheds light on the characteristics of Medellín’s economic development since the early 2000s. Elites with minimal technological capabilities and interests in promoting the advancement of transnational capitalism have successfully secured access to sources of power. These conditions (re)produce neoliberal logics of local governance that focus on economic growth in sectors with perceived global comparative advantages and on sustaining the particular power balances in Medellín’s political settlement. This has led to failures of generating positive forward and backward linkages for productivity growth of local firms, a local labour market marked by low wages and high employment elasticities, and large income inequalities. The local governance model that perpetuates productivity and inequality problems of the city is adopted as an opportunistic discourse of Medellín’s transnationalised capitalist elite in the larger neoliberal context of Colombia’s polity and economic policy agenda. In the absence of structural reforms targeting low wages and incentivising firms to develop technological capabilities, Medellín’s low productivity and high inequality problems are likely to persist

    Novel magnetically induced healing in road pavements

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    Around the globe, maintenance costs to repair asphalt roads during their service life often exceed the available budget of road authorities and municipalities. This chapter explores novel approaches to generate engineered healing capabilities through induction heating of ferrous material-asphalt composites. These include ferromagnetic fillers, ferrous fibers, mixed-metal alloy fibers, and recycled fibers from shredded vehicle tires, among others. This approach is expected to contribute in decreasing the amount of maintenance needed for road pavements by extending their service life and promoting microcracks closure (healing). Experimental results showed that the temperature of the composite samples increased under the alternative magnetic field, reaching high-temperature values in a very small amount of time, hence promoting a rapid closure of microcracks in asphalt
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