143 research outputs found

    Antarctic/Scotia plate convergence off southernmost Chile

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    The southern tip of South America off Chile has suffered a long phase of ocean-continent convergence which has shaped the continental margin through different phases of accretion and tectonic erosion. The present accretionary wedge is a discontinuous geological record of plate convergence and records only part of the accretionary processes resumed after Chile ridge consumption (14 Ma). The structural style of the subduction complex, such as rates of sediment accretion and tectonic erosion, structural vergence, width of the accretionary wedge, taper angle and deformation in the forearc basin, varies along the margin. Large taper values are related to narrow wedges and seaward vergent structures. Low tapers occur where deformation at the toe of the accretionary complex is spread over wide areas and is related both to landward and seaward vergent thrust faults. Seismic data interpretation contributes to define more accurately frontal wedge morphology and geometry of subduction and suggests that different modes of accretion together with tectonic erosion may be active concurrently along the trench at different locations. In areas of subduction driven accretionary processes the majority of trench sediments are involved in accretionary processes and sediments are uplifted and piled up in the form of imbricate thrust sheets. In areas where the wedge is non-accretionary the continental margin shows steeper continental slopes associated with narrow accretionary wedges, more intense sediment disruption and very shallow décollement levels. Variation in structural style and in the geometry of the forearc region setting off Southernmost Chile, has been interpreted as related to the existence of different structural domains: the nature of their boundaries is still unclear mainly for the lack of high resolution bathymetric data. They have been tentatively related to tectonic lineaments belonging to the Magellan Fault system and/or to the character and morphology of the converging plates (lateral heterogeneities, sea-mounts and fracture zones), which produce a segmentation of the margin

    Coral Patch and Ormonde seamounts as a product of the Madeira hotspot, Eastern Atlantic Ocean

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    New detailed swath bathymetry and bottom samples from Coral Patch and Ormonde seamounts provide constraints on the emplacement of the Madeira hotspot in the Eastern Atlantic Ocean. Swath bathymetric data document that Coral Patch is a composite structure, made up of at least nine distinct volcanic centres. Lithified pelagic carbonates infilling fissures in lava blocks constrain a minimal age for the volcanism in the Early Miocene and represent the first documentation of Coral Patch acting as an offshore terrigenous-starved seamount. At Coral Patch, as already observed at the Ormonde seamount, volcanism was emplaced on top of a pre-existing relief resulting from the regional tectonic compressive regime

    Report of a rare case of colon cancer complicated by anomalies of intestinal rotation and fixation: a case report

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    Introduction: The Situs viscerum inversus associated with anomalies of intestinal rotation and fixation is an extremely rare condition. To the authors' knowledge, this is the first report of colon cancer associated with intestinal malrotation and mesenterium ileocolicum commune. Case presentation: A 34-year-old man with a 2-month history of diarrhea associated with abdominal pain and weight loss underwent abdominal ultrasonography, colonscopy with biopsies and abdominal computed tomography scan with intravenous contrast. A right colonic neoplasm was diagnosed, observed only at surgery, as neither computed tomography or ultrasonography showed the intestinal malrotation. Particularly, the third and the fourth part of the duodenum descended vertically, without Treitz's ligament in support to the duodeno-jejunal flexure. The small bowel and the colon were located in the right and left side of the abdominal cavity, respectively. Conclusion: The anomaly of situs viscerum inversus influenced the surgical strategy in this case because of the vascular and lymphatic anomalies. Lymphatic vessels were therefore marked with subserosal injection of patent blue in the proximity of the tumor. Subsequently, right colectomy was performed. Colectomy extended from the distal ileum to the descending colon, by ligature of the right colic artery and vein at the origin from the superior mesenteric vessels. Patent blue guided lymphadenectomy was also performed with curative intent. Finally, a mechanical ileo-colic anastomosis was carried out. After right colectomy and ileo-descending anastomosis, the Ladd's procedure for intestinal malrotation was unnecessary. The authors believe that this strategy, despite the anatomical difficulties, represents an effective procedure for the radical surgical treatment of the right colon cancer associated with anomalies of intestinal rotation and fixatio

    Misidentification of Streptococcus uberis as a human pathogen: a case report and literature review.

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    Summary Streptococcus uberis is an environmental bacterium responsible for bovine mastitis. It is occasionally described as a human pathogen, though in most cases the identification was based on biochemical phenotyping techniques. This report shows that the biochemical phenotyping may incorrectly identify Enterococcus faecium as S. uberis

    Fine-needle aspiration accuracy in the diagnosis of primary epithelioid angiosarcoma of the adrenal gland: a case report and review of the literature

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    Primary epithelioid angiosarcoma of the adrenal gland is extremely rare. Only 37 cases have been reported in the scientific literature.Here we describe the case of a 55-year-old woman affected by metastatic angiosarcoma in the right adrenal gland, who died few days after the histological diagnosis made by fine-needle aspiration (FNA). This is the second case of primary epithelioid angiosarcoma diagnosed by FNA among scientific articles published in English in PubMed. Microscopically, the tumor showed a predominant epithelioid differentiation, thus making the diagnostic process more difficult than usual. Immunohistochemical examination revealed positive reactivity for cytokeratin, CD31, and CD34. The literature shows that epithelioid adrenal angiosarcoma has poor clinical outcome, especially when metastatic at presentation

    Influence of LV Neutral Grounding on Global Earthing Systems

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    International Standards define a Global Earthing System as an earthing net created interconnecting local Earthing Systems (generally through the shield of MV cables and/or bare buried conductors). In Italy, the regulatory authority for electricity and gas requires distributors to guarantee the electrical continuity of LV neutral conductor. This requirement has led to the standard practice of realizing “reinforcement groundings” along the LV neutral conductor path and at users' delivery cabinet. Moreover, in urban high-load scenarios (prime candidates to be part of a Global Earthing System), it is common that LV distribution scheme creates, through neutral conductors, an effective connection between grounding systems of MV/LV substations, modifying Global Earthing System consistency. The aim of this paper is to evaluate the effect, in terms of electrical safety, of the aforementioned LV neutral distribution scheme when an MV-side fault to ground occurs. For this purpose, simulations are carried out on a realistic urban test case and suitable evaluation indexes are proposed

    Non-Pathogenic Aspergillus oryzae Acute Exogenous Endophthalmitis after Penetrating Keratoplasty: The First Case Report in the Literature

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    The authors report a singular case of post-operative exogenous fungal endophthalmitis caused by a non-pathogenic fungal agent: Aspergillus oryzae. A 75-year-old Caucasian woman with post-penetrating keratoplasty fungal endophthalmitis due to a nonpathogenic A. oryzae, resistant to the current azoles anti-fungal agents, was treated with subtotal vitrectomy, intravitreal injection, and systemic voriconazole therapy. Complete resolution of the endophthalmitis occurred after two subsequent intravitreal injections and a 2-month-long systemic delivery of voriconazole. The quick identification of the fungal agent allowed immediate and targeted therapy. In the article, the safety and efficacy of both systemic and intravitreal voriconazole treatments are discussed

    Large symptomatic gastric diverticula: two case reports and a brief review of literature

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    Gastric diverticula are rare and uncommon conditions. Most gastric diverticula are asymptomatic. When symptoms arise, they are most commonly upper abdominal pain, nausea and emesis, while dyspepsia and vomiting are less common. Occasionally, patients with gastric diverticula can have dramatic presentations related to massive bleeding or perforation. The diagnosis may be difficult, as symptoms can be caused by more common gastrointestinal pathologies and only aggravated by diverticula. The appropriate management of diverticula depends mainly on the symptom pattern and as well as diverticulum size. There is no specific therapeutic strategy for an asymptomatic diverticulum. Although some authors support conservative therapy with antacids, this provides only temporary symptom relief since it is not able to resolve the underlying pathology. Surgical resection is the mainstay of treatment when the diverticulum is large, symptomatic or complicated by bleeding, perforation or malignancy, with over two-thirds of patients remaining symptom-free after surgery, while laparoscopic resection, combined with intraoperative endoscopy, is a safe and feasible approach with excellent outcomes. Here, we present two cases of uncommon large symptomatic gastric diverticula with a discussion of the cornerstones in management and report a minimally invasive solution, with a brief review of the literature. (C) 2013 Baishideng. All rights reserved

    LIME -- a gas TPC prototype for directional Dark Matter search for the CYGNO experiment

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    The CYGNO experiment aims at the development of a large gaseous TPC with GEM-based amplification and an optical readout by means of PMTs and scientific CMOS cameras for 3D tracking down to O(keV) energies, for the directional detection of rare events such as low mass Dark Matter and solar neutrino interactions. The largest prototype built so far towards the realisation of the CYGNO experiment demonstrator is the 50 L active volume LIME, with 4 PMTs and a single sCMOS imaging a 33×\times33 cm\textsuperscript{2} area for 50 cm drift, that has been installed in underground Laboratori Nazionali del Gran Sasso in February 2022. We will illustrate LIME performances as evaluated overground in Laboratori Nazionali di Frascati by means of radioactive X-ray sources, and in particular the detector stability, energy response and energy resolution. We will discuss the MC simulation developed to reproduce the detector response and show the comparison with actual data. We will furthermore examine the background simulation worked out for LIME underground data taking and illustrate the foreseen expected measurement and results in terms of natural and materials intrinsic radioactivity characterisation and measurement of the LNGS underground natural neutron flux. The results that will be obtained by underground LIME installation will be paramount in the optimisation of the CYGNO demonstrator, since this is foreseen to be composed by multiple modules with the same LIME dimensions and characteristics

    Technical Design Report - TDR CYGNO-04/INITIUM

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    The aim of this Technical Design Report is to illustrate the technological choices foreseen to be implemented in the construction of the CYGNO-04 demonstrator, motivate them against the experiment physics goals of CYGNO-30 and demonstrate the financial sustainability of the project. CYGNO-04 represents PHASE 1 of the long term CYGNO roadmap, towards the development of large high precision tracking gaseous Time Projection Chamber (TPC) for directional Dark Matter searches and solar neutrino spectroscopy. The CYGNO project1 peculiarities reside in the optical readout of the light produced during the amplification of the primary ionization electrons in a stack of triple Gas Electron Multipliers (GEMs), thanks to the nice scintillation properties of the chosen He:CF4 gas mixture. To this aim, CYGNO is exploiting the fast progress in commercial scientific Active Pixel Sensors (APS) development for highly performing sCMOS cameras, whose high granularity and sensitivity allow to significantly boost tracking, improve particle identification and lower the energy threshold. The X-Y track project obtained from the reconstruction of the sCMOS images is combined with a PMT measurement to obtain a full 3D track reconstruction. In addition, several synergic R&Ds based on the CYGNO experimental approach are under development in the CYGNO collaboration (see Sec 2) to further enhance the light yield by means of electro luminescence after the amplification stage, to improve the tracking performances by exploiting negative ion drift operation within the INITIUM ERC Consolidator Grant, and to boost the sensitivity to O(GeV) Dark Matter masses by employing hydrogen rich target towards the development of PHASE 2 (see Sec. 1.2). While still under optimization and subject to possible significant improvements, the CYGNO experimental approach performances and capabilities demonstrated so far with prototypes allow to foresee the development of an O(30) m3 experiment by 2026 for a cost of O(10) MEUROs. A CYGNO-30 experiment would be able to give a significant contribution to the search and study of Dark Matter with masses below 10 GeV/c2 for both SI and SD coupling. In case of a Dark Matter observation claim by other experiments, the information provided by a directional detector such as CYGNO would be fundamental to positively confirm the galactic origin of the allegedly detected Dark Matter signal. CYGNO-30 could furthermore provide the first directional measurement of solar neutrinos from the pp chain, possibly extending to lower energies the Borexino measurement2. In order to reach this goal, the CYGNO project is proceeding through a staged approach. The PHASE 0 50 L detector (LIME, recently installed underground LNGS) will validate the full performances of the optical readout via APS commercial cameras and PMTs and the Montecarlo simulation of the expected backgrounds. The full CYGNO-04 demonstrator will be realized with all the technological and material choices foreseen for CYGNO-30, to demonstrate the scalability of the experimental approach and the potentialities of the large PHASE 2 detector to reach the expected physics goals. The first PHASE 1 design anticipated a 1 m3 active volume detector with two back-to-back TPCs with a central cathode and 500 mm drift length. Each 1 m2 readout area would have been composed by 9 + 9 readout modules having the LIME PHASE 0 dimensions and layout. Time (end of INITIUM project by March 2025) and current space availability at underground LNGS (only Hall F) forced the rescaling of the PHASE 1 active volume and design to a 0.4 m3, hence CYGNO-04. CYGNO-04 will keep the back-to-back double TPC layout with 500 mm drift length each, but with an 800 x 500 mm2 readout area covered by a 2 + 2 modules based on LIME design. The reduction of the detector volume has no impact on the technological objectives of PHASE 1, since the modular design with central cathode, detector materials and shieldings and auxiliary systems are independent of the total volume. The physics reach (which is a byproduct of PHASE 1 and NOT an explicit goal) will be only very partially reduced (less than a factor 2 overall) since a smaller detector volume implies also a reduced background from internal materials radioactivity. In addition, the cost reduction of CYGNO-04 of about 1⁄3 with respect to CYGNO-1 illustrated in the CDR effectively makes the overall project more financially sustainable (see CBS in the last section). In summary this document will explain: the physical motivation of the CYGNO project and the technical motivations of the downscale of the PHASE 1 to CYGNO-04, 400 liters of active volume, with respect to the demonstrator presented in the CDR; the results of R&D and the Montecarlo expectations for PHASE 0; the technical choices, procedures and the executive drawings of CYGNO-04 in the Hall F of the LNGS; safety evaluations and the interference/request to the LNGS services; Project management, WBS/WBC, WP, GANTT, ec
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