454 research outputs found

    Origin and significance of olistostromes in the evolution of orogenic belts: A global synthesis

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    Olistostromes (sedimentary m\ue9langes) represent the products of ancient submarine mass transport processes. We present a comparative analysis of the occurrences and internal structures of these sedimentary m\ue9langes at a global scale with a focus on the Circum-Mediterranean, Appalachian and Circum-Pacific regions, and discuss their formation and time-progressive evolution in different tectonic settings. Lithological compositions, stratigraphy, and structural features of olistostromes reflect the operation of an entire spectrum of mass transport processes during their development through multi-stage deformation phases. The general physiography and tectonic setting of their depocenters, the nature, scale and rate of downslope transformation mechanisms, and global climatic events are the main factors controlling the internal structure and stratigraphy of olistostromes. Based on the tectonic settings of their formation olistostromes are classified as: (i) passive margin, (ii) convergent margin and subduction\u2013accretion, and (iii) collisional and intra-collisional types. Systematic repetitions of these different olistostrome types in different orogenic belts provide excellent markers for the timing of various tectonic events during the Wilson cycle evolution of ocean basins. Olistostromes are best preserved in paleo active margins, covering vast areas of thousands of km2, where they underwent significant downslope translation, up to hundreds of kilometers. Incorporation of olistostromes into subduction\u2013accretion complexes and orogenic belts takes place during discrete episodes of tectonic events, and their primary (sedimentary) fabric may be commonly reworked and overprinted by subsequent phases of tectonic and metamorphic events. We apply the basic nomenclature of structural geology, sedimentology and basin analysis in studying the internal structure, lithological makeup, and mechanisms of formation and extraordinary downslope mobility of olistostromes

    Revascularisation of Chronic Limb Threatening Ischaemia in Patients with no Pedal Arteries Leads to Lower Midterm Limb Salvage

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    Objective: Chronic limb threatening ischaemia (CLTI) involving the infragenicular arteries is treated by distal angioplasty or pedal bypass; however, this is not always possible, due to chronically occluded pedal arteries (no patent pedal artery, N-PPA). This pattern represents a hurdle to successful revascularisation, which must be limited to the proximal arteries. The aim of the study was to analyse the outcome of patients with CLTI and N-PPA after a proximal revascularisation.Methods: All patients with CLTI submitted to revascularisation in a single centre (2019 - 2020) were analysed. All angiograms were reviewed to identify N-PPA, defined as total obstruction of all pedal arteries. Revascularisation was performed with proximal surgical, endovascular, and hybrid procedures. Early and midterm survival, wound healing, limb salvage, and patency rates were compared between N-PPA and patients with one or more patent pedal artery (PPA).Results: Two hundred and eighteen procedures were performed. One hundred and forty of 218 (64.2%) patients were male, mean age 73.2 & PLUSMN; 10.6 years. The procedure was surgical in 64/218 (29.4%) cases, endovascular in 138/218 (63.3%), and hybrid in 16/218 (7.3%). N-PPA was present in 60/218 (27.5%) cases. Eleven of 60 (18.3%) cases were treated surgically, 43/60 (71.7%) by endovascular and 6/60 (10%) by hybrid procedures. Technical success was similar in the two groups (N-PPA 85% vs. PPA 82.3%, p = .42). At a mean follow up of 24.5 & PLUSMN; 10.2 months, survival (N-PPA 93.7 & PLUSMN; 3.5% vs. PPA 95.3 & PLUSMN; 2.1%, p = .22) and primary patency (N-PPA 53.1 & PLUSMN; 8.1% vs. PPA 55.2 & PLUSMN; 5%, p = .56) were similar. Limb salvage was significantly lower in N-PPA patients (N-PPA 71.4 & PLUSMN; 6.6% vs. PPA 81.5 & PLUSMN; 3.4%, p = .042); N-PPA was an independent predictor of major amputation (hazard ratio [HR] 2.02, 1.07 - 3.82, p = .038) together with age > 73 years (HR 2.32, 1.17 4.57, p = .012) and haemodialysis (2.84, 1.48 - 5.43, p = .002).Conclusion: N-PPA is not uncommon in patients with CLTI. This condition does not hamper technical success, primary patency, and midterm survival; however, midterm limb salvage is significantly lower than in patients with PPA. This should be considered in the decision making process

    Improving Car Model Classification through Vehicle Keypoint Localization

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    In this paper, we present a novel multi-task framework which aims to improve the performance of car model classification leveraging visual features and pose information extracted from single RGB images. In particular, we merge the visual features obtained through an image classification network and the features computed by a model able to predict the pose in terms of 2D car keypoints. We show how this approach considerably improves the performance on the model classification task testing our framework on a subset of the Pascal3D dataset containing the car classes. Finally, we conduct an ablation study to demonstrate the performance improvement obtained with respect to a single visual classifier network
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