4,633 research outputs found
Water Mass Transport Changes through the Venice Lagoon Inlets from Projected Sea-Level Changes under a Climate Warming Scenario
In this study, an ensemble of numerical simulations with a state-of-the-art hydrodynamic model for coastal applications is used to characterize, for the first time, the expected mid-21st-century changes in circulation and associated sea-level height inside the Venice lagoon induced by projected Mediterranean sea level rise and atmospheric circulation changes over the Adriatic Sea under the RCP8.5 emission scenario. Our results show that water transports through the three inlets connecting the Venice lagoon to the open sea are expected to change significantly, with consequent significant persistent alterations of the circulation and sea-level height inside the lagoon. The projected water mass redistributions motivate further studies on the implications of climate change for the lagoon environment
Plume spreading test case for coastal ocean models
We present a test case of river plume spreading to evaluate numerical methods used in coastal ocean modeling. It includes an estuary–shelf system whose dynamics combine nonlinear flow regimes with sharp frontal boundaries and linear regimes with cross-shore geostrophic balance. This system is highly sensitive to physical or numerical dissipation and mixing. The main characteristics of the plume dynamics are predicted analytically but are difficult to reproduce numerically because of numerical mixing present in the models. Our test case reveals the level of numerical mixing as well as the ability of models to reproduce nonlinear processes and frontal zone dynamics. We document numerical solutions for the Thetis and FESOM-C models on an unstructured triangular mesh, as well as ones for the GETM and FESOM-C models on a quadrilateral mesh. We propose an analysis of simulated plume spreading which may be useful in more general studies of plume dynamics.
The major result of our comparative study is that accuracy in reproducing the analytical solution depends less on the type of model discretization or computational grid than it does on the type of advection scheme.</p
FESOM-C v.2: coastal dynamics on hybrid unstructured meshes
We describe FESOM-C, the
coastal branch of the Finite-volumE Sea ice – Ocean Model (FESOM2), which
shares with FESOM2 many numerical aspects, in particular its finite-volume
cell-vertex discretization. Its dynamical core differs in the implementation
of time stepping, the use of a terrain-following vertical coordinate, and the
formulation for hybrid meshes composed of triangles and quads. The first two
distinctions were critical for coding FESOM-C as an independent branch. The
hybrid mesh capability improves numerical efficiency, since quadrilateral
cells have fewer edges than triangular cells. They do not suffer from
spurious inertial modes of the triangular cell-vertex discretization and need
less dissipation. The hybrid mesh capability allows one to use
quasi-quadrilateral unstructured meshes, with triangular cells included only
to join quadrilateral patches of different resolution or instead of strongly
deformed quadrilateral cells. The description of the model numerical part is
complemented by test cases illustrating the model performance.</p
Вибір способу біліарної декомпресії у хворих на обтураційну жовтяницю непухлинного генезу
The aim of the work: to study efficiency of biliary decompression after external and internal drainage of bile ducts, endoscopic transpapillary interventions in patients with obstructive jaundice of non-tumor genesis.
Materials and Methods. We analyzed the outcomes of surgical treatment of 200 patients with obstructive jaundice of the non-tumor genesis. The patients were divided into three groups: group I (n = 95), where endoscopic methods of biliary decompression were used; group II (n = 48), where biliodigestive anastomoses were formed; and group III (n = 57), where the external drainage of bile ducts was conducted.
Results and Discussion. The patients of the group I demonstrated a gradual decrease of bilirubin and alkaline phosphatase levels, which reached the normal readings on day 7. The patients of the group II demonstrated normal levels of bilirubin and alkaline phosphatase on day 14. The patients of the group III demonstrated rapid decrease of bilirubin and alkaline phosphatase levels, which reached the normal readings on day 28. The transaminase level in each group of patients had reached the norm earlier.Цель работы: изучить эффективность билиарной декомпрессии после внешнего, внутреннего дренирования желчных протоков, эндоскопических транспапилярных вмешательств у больных с обтурационной желтухой неопухолевого генеза.
Материалы и методы. Проанализированы результаты хирургического лечения 200 больных с обтурационной желтухой доброкачественного генеза. Больные были разделены на три группы: I группа (n = 95) – применяли эндоскопические способы билиарной декомпрессии, II группа (n = 48) – сформировано билиодигестивные анастомозы, III группа (n = 57) – проводили наружное дренирование желчных протоков.
Результаты исследований и их обсуждение. В І группе больных наблюдалось постепенное снижение уровня билирубина и щелочной фосфатазы и достижения нормального уровня на 7 сутки. Во ІІ группе нормализацию билирубина и щелочной фосфатазы отмечено на 14 сутки. В ІІІ группе было быстрое снижение уровня билирубина и щелочной фосфатазы и их нормализация на 28 сутки. Уровень трансаминаз достигал нормы раньше в каждой группе больных.Мета роботи: вивчити ефективність біліарної декомпресії після зовнішнього, внутрішнього дренування жовчних проток, ендоскопічних транспапілярних втручань у хворих на обтураційну жовтяницю непухлинного генезу.
Матеріали і методи. Проаналізовано результати хірургічного лікування 200 хворих на обтураційну жовтяницю доброякісного генезу. Хворі були розподілені на три групи: І група (n = 95) – застосовували ендоскопічні способи біліарної декомпресії, ІІ група (n = 48) – сформовано біліодигестивні анастомози, ІІІ група (n = 57) – проводили зовнішнє дренування жовчних проток.
Результати досліджень та їх обговорення. У І групі хворих спостерігалось поступове зниження рівня білірубіну та лужної фосфатази і досягнення нормального рівня на 7 добу. У ІІ групі нормалізацію білірубіну і лужної фосфатази відмічено на 14 добу. У ІІІ групі було швидке зниження рівня білірубіну та лужної фосфатази та їхньої нормалізації на 28 добу. Рівень трансаміназ досягав норми раніше у кожній групі хворих
Towards the new thematic Core service Tsunami within the EPOS research infrastructure
Tsunamis constitute a significant hazard for European coastal populations, and the impact of tsunami events worldwide can extend well beyond the coastal regions directly affected. Understanding the complex mechanisms of tsunami generation, propagation, and inundation, as well as managing the tsunami risk, requires multidisciplinary research and infrastructures that cross national boundaries. Recent decades have seen both great advances in tsunami science and consolidation of the European tsunami research community. A recurring theme has been the need for a sustainable platform for coordinated tsunami community activities and a hub for tsunami services. Following about three years of preparation, in July 2021, the European tsunami community attained the status of Candidate Thematic Core Service (cTCS) within the European Plate Observing System (EPOS) Research Infrastructure. Within a transition period of three years, the Tsunami candidate TCS is anticipated to develop into a fully operational EPOS TCS. We here outline the path taken to reach this point, and the envisaged form of the future EPOS TCS Tsunami. Our cTCS is planned to be organised within four thematic pillars: (1) Support to Tsunami Service Providers, (2) Tsunami Data, (3) Numerical Models, and (4) Hazard and Risk Products. We outline how identified needs in tsunami science and tsunami risk mitigation will be addressed within this structure and how participation within EPOS will become an integration point for community developmen
Compressed representation of a partially defined integer function over multiple arguments
In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one
Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV
The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8 TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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