| 1. |
- Dorschel, Boris, et al.
(författare)
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The International Bathymetric Chart of the Southern Ocean Version 2
- 2022
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Ingår i: Scientific Data. - : Springer Science and Business Media LLC. - 2052-4463. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- The Southern Ocean surrounding Antarctica is a region that is key to a range of climatic and oceanographic processes with worldwide effects, and is characterised by high biological productivity and biodiversity. Since 2013, the International Bathymetric Chart of the Southern Ocean (IBCSO) has represented the most comprehensive compilation of bathymetry for the Southern Ocean south of 60 degrees S. Recently, the IBCSO Project has combined its efforts with the Nippon Foundation - GEBCO Seabed 2030 Project supporting the goal of mapping the world's oceans by 2030. New datasets initiated a second version of IBCSO (IBCSO v2). This version extends to 50 degrees S (covering approximately 2.4 times the area of seafloor of the previous version) including the gateways of the Antarctic Circumpolar Current and the Antarctic circumpolar frontal systems. Due to increased (multibeam) data coverage, IBCSO v2 significantly improves the overall representation of the Southern Ocean seafloor and resolves many submarine landforms in more detail. This makes IBCSO v2 the most authoritative seafloor map of the area south of 50 degrees S.
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| 2. |
- García Butenegro, German, et al.
(författare)
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Divisibility in Hom-Algebras, Single-Element Properties in Non-associative Algebras and Twisted Derivations
- 2023
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Ingår i: Non-commutative and Non-associative Algebra and Analysis Structures. - : Springer. - 9783031320088 ; , s. 303-337
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Konferensbidrag (refereegranskat)abstract
- We compare and examine the influence of Hom-associativity, involving a linear map twisting the associativity axiom, on fundamental aspects important in study of Hom-algebras and (σ,τ)-derivations satisfying a (σ,τ)-twisted Leibniz product rule in connection to Hom-algebra structures. As divisibility may be not transitive in general not necessarily associative algebras, we explore factorization properties of elements in Hom-associative algebras, specially related to zero divisors, and develop an α-deformed divisibility sequence, formulated in terms of linear operators. We explore effects of the twisting maps σ and τ on the whole space of twisted derivations, unfold some partial results on the structure of (σ,τ)-derivations on arbitrary algebras based on a pivot element related to σ and τ and examine how general an algebra can be while preserving certain well-known relations between (σ,τ)-derivations. Furthermore, new more general axioms of Hom-associativity, Hom-alternativity and Hom-flexibility modulo kernel of a derivation are introduced leading to new classes of Hom-algebras motivated by (σ,τ)-Leibniz rule over multiplicative maps σ and τ and study of twisted derivations in arbitrary algebras and their connections to Hom-algebra structures.
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| 3. |
- García Butenegro, German, et al.
(författare)
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Elduque-Myung Type Mutations of Hom-algebras
- 2023
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Ingår i: Algebra without Borders – Classical and Constructive Nonassociative Algebraic Structures. - : Springer. - 9783031393334 - 9783031393341 ; , s. 295-330
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Bokkapitel (refereegranskat)abstract
- Elduque-Myung type mutations of general, possibly non-associative, algebras and of several classes of Hom-algebras are explored. Several extensions of the results from scalar and non-scalar mutations of associative algebras to mutations of non-associative algebras and of several kinds of hom-algebras of hom-associative type are obtained, including general conditions, in terms of Hom-associators, commutators and general mutation elements (mutations parameters), for mutated Hom-algebras or non-associative algebras to be Hom-associative, Hom-flexible, 3-Hom-Power associative, as well as results on reductions of double parameter mutations to single parameter mutations in algebras and Hom-algebras. Several formulas for mutations of associative algebras are extended to arbitrary possibly non-associative algebras and Hom-algebras.
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| 4. |
- García Butenegro, German, et al.
(författare)
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On Lie-Type Constructions over Twisted Derivations
- 2023
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Ingår i: Non-commutative and Non-associative Algebra and Analysis Structures. - : Springer. - 9783031320088 ; , s. 339-380
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Konferensbidrag (refereegranskat)abstract
- In this paper we examine interactions between (σ, τ) -derivations via commutator and consider new n-ary structures based on twisted derivation operators. We show that the sums of linear spaces of (σk, τl) -derivations and also of some of their subspaces, consisting of twisted derivations with some commutation relations with σ and τ, form Lie algebras, and moreover with the semigroup or group graded commutator product, yielding graded Lie algebras when the sum of the subspaces is direct. Furthermore, we extend these constructions of such Lie subalgebras spanned by twisted derivations of algebras to twisted derivations of n-ary algebras. Finally, we consider n-ary products defined by generalized Jacobian determinants based on (σ,τ) -derivations, and construct n-Hom-Lie algebras associated to the generalized Jacobian determinants based on twisted derivations extending some results of Filippov to (σ,τ) -derivations. We also establish commutation relations conditions for twisting maps and twisted derivations such that the generalised Jacobian determinant products yield (σ,τ,n) -Hom-Lie algebras, a new type of n-ary Hom-algebras different from n-Hom-Lie algebras in that the positions of twisting maps σ and τ are not fixed to positions of variables in n-ary products terms of the sum of defining identity as they were in Hom-Nambu-Filippov identity of n-Hom-Lie algebras.
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| 5. |
- Jess, David Unnersjö, et al.
(författare)
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Deep learning-based segmentation and quantification of podocyte foot process morphology suggests differential patterns of foot process effacement across kidney pathologies
- 2023
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Ingår i: Kidney International. - : Elsevier BV. - 0085-2538 .- 1523-1755. ; 103:6, s. 1120-1130
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Tidskriftsartikel (refereegranskat)abstract
- Morphological alterations at the kidney filtration barrier increase intrinsic capillary wall permeability resulting in albuminuria. However, automated, quantitative assessment of these morphological changes has not been possible with electron or light microscopy. Here we present a deep learning-based approach for segmentation and quantitative analysis of foot processes in images acquired with confocal and super-resolution fluorescence microscopy. Our method, Automatic Morphological Analysis of Podocytes (AMAP), accurately segments podocyte foot processes and quantifies their morphology. AMAP applied to a set of kidney diseases in patient biopsies and a mouse model of focal segmental glomerulosclerosis allowed for accurate and comprehensive quantification of various morphometric features. With the use of AMAP, detailed morphology of podocyte foot process effacement was found to differ between categories of kidney pathologies, showed detailed variability between diverse patients with the same clinical diagnosis, and correlated with levels of proteinuria. AMAP could potentially complement other readouts such as various omics, standard histologic/electron microscopy and blood/urine assays for future personalized diagnosis and treatment of kidney disease. Thus, our novel finding could have implications to afford an understanding of early phases of kidney disease progression and may provide supplemental information in precision diagnostics.
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| 6. |
- Kozlov, Vladimir, et al.
(författare)
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A fractal graph model of capillary type systems
- 2018
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Ingår i: Complex Variables and Elliptic Equations. - : TAYLOR & FRANCIS LTD. - 1747-6933 .- 1747-6941. ; 63:7-8, s. 1044-1068
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Tidskriftsartikel (refereegranskat)abstract
- We consider blood flow in a vessel with an attached capillary system. The latter is modelled with the help of a corresponding fractal graph whose edges are supplied with ordinary differential equations obtained by the dimension-reduction procedure from a three-dimensional model of blood flow in thin vessels. The Kirchhoff transmission conditions must be satisfied at each interior vertex. The geometry and physical parameters of this system are described by a finite number of scaling factors which allow the system to have self-reproducing solutions. Namely, these solutions are determined by the factors values on a certain fragment of the fractal graph and are extended to its rest part by virtue of these scaling factors. The main result is the existence and uniqueness of self-reproducing solutions, whose dependence on the scaling factors of the fractal graph is also studied. As a corollary we obtain a relation between the pressure and flux at the junction, where the capillary system is attached to the blood vessel. This relation leads to the Robin boundary condition at the junction and this condition allows us to solve the problem for the flow in the blood vessel without solving it for the attached capillary system.
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| 7. |
- Kozlov, Vladimir, 1954-, et al.
(författare)
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Modeling of Fluid Flow in a Flexible Vessel with Elastic Walls
- 2021
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Ingår i: Journal of Mathematical Fluid Mechanics. - : Springer Nature. - 1422-6928 .- 1422-6952. ; 23:3
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Tidskriftsartikel (refereegranskat)abstract
- We exploit a two-dimensional model (Ghosh et al. in Q J Mech Appl Math 71(3):349-367, 2018; Kozlov and Nazarov in Dokl Phys 56(11):560-566, 2011, J Math Sci 207(2):249-269, 2015) describing the elastic behavior of the wall of a flexible blood vessel which takes interaction with surrounding muscle tissue and the 3D fluid flow into account. We study time periodic flows in an infinite cylinder with such intricate boundary conditions. The main result is that solutions of this problem do not depend on the period and they are nothing else but the time independent Poiseuille flow. Similar solutions of the Stokes equations for the rigid wall (the no-slip boundary condition) depend on the period and their profile depends on time.
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| 8. |
- Kozlov, Vladimir, 1954-, et al.
(författare)
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Pressure drop matrix for a bifuration of an artery with defects
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We consider a bifurcation of an artery. The influence of defects of the vessel's wall near the bifurcation point on the pressure drop matrix is analyzed. The elements of this matrix are included in the modified Kirchhoff transmission conditions, which were introduced earlier in [1], [2], and which describe adequately the total pressure loss at the bifurcation point of the flow passed through it.
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