153 research outputs found
Existence of global weak solutions to some regularized kinetic models for dilute polymers
Published versio
Decay of the total variation and Hardy norms of solutions to parabolic conservation laws
We study the decay of solutions to parabolic conservation laws in the Hardy space and in the total variation norm. We show that solutions to scalar equations and systems decay to zero without a rate in , and that the total variation of solutions decays to zero at an algebraic rate
Existence of global weak solutions to compressible isentropic finitely extensible bead-spring chain models for dilute polymers
We prove the existence of global-in-time weak solutions to a general class of models that arise from the kinetic theory of dilute solutions of nonhomogeneous polymeric liquids, where the polymer molecules are idealized as bead-spring chains with finitely extensible nonlinear elastic (FENE) type spring potentials. The class of models under consideration involves the unsteady, compressible, isentropic, isothermal Navier–Stokes system in a bounded domain Ω in Rd, d = 2 or 3, for the density ρ, the velocity u∼ and the pressure p of the fluid, with an equation of state of the form p(ρ) = cpρ γ, where cp is a positive constant and γ > 3 2 . The right-hand side of the Navier–Stokes momentum equation includes an elastic extra-stress tensor, which is the sum of the classical Kramers expression and a quadratic interaction term. The elastic extra-stress tensor stems from the random movement of the polymer chains and is defined through the associated probability density function that satisfies a Fokker–Planck-type parabolic equation, a crucial feature of which is the presence of a centre-of-mass diffusion term
Laboratory evaluation of hedmanite and lime modified asphalt concrete mixes
We prove the existence of large-data global-in-time weak solutions to an
evolutionary PDE system describing flows of incompressible
\emph{heat-conducting} viscoelastic rate-type fluids with stress-diffusion,
subject to a stick-slip boundary condition for the velocity and a homogeneous
Neumann boundary condition for the extra stress tensor. In the introductory
section we develop the thermodynamic foundations of the proposed model, and we
document the role of thermodynamics in obtaining critical structural relations
between the quantities of interest. These structural relations are then
exploited in the mathematical analysis of the governing equations. In
particular, the definition of weak solution is motivated by the thermodynamic
basis of the model.
The extra stress tensor describing the elastic response of the fluid is in
our case purely spherical, which is a simplification from the physical point of
view. The model nevertheless exhibits features that require novel mathematical
ideas in order to deal with the technically complex structure of the associated
internal energy and the more complicated forms of the corresponding entropy and
energy fluxes. The paper provides the first rigorous proof of the existence of
large-data global-in-time weak solutions to the governing equations for
\emph{coupled thermo-mechanical processes} in viscoelastic rate-type fluids
Discontinuous Galerkin finite element approximation of quasilinear elliptic boundary value problems II: strongly monotone quasi-Newtonian flows
Strong and auxiliary forms of the semi-Lagrangian method for incompressible flows
We present a review of the semi-Lagrangian method for advection-diusion and incompressible Navier-Stokes equations discretized with high-order methods. In particular, we compare the strong form where the departure points are computed directly via backwards integration with the auxiliary form where an auxiliary advection equation is solved instead; the latter is also referred to as Operator Integration Factor Splitting (OIFS) scheme. For intermediate size of time steps the auxiliary form is preferrable but for large time steps only the strong form is stable
Presynaptic partner selection during retinal circuit reassembly varies with timing of neuronal regeneration in vivo
Whether neurons can restore their original connectivity patterns during circuit repair is unclear. Taking advantage of the regenerative capacity of zebrafish retina, we show here the remarkable specificity by which surviving neurons reassemble their connectivity upon regeneration of their major input. H3 horizontal cells (HCs) normally avoid red and green cones, and prefer ultraviolet over blue cones. Upon ablation of the major (ultraviolet) input, H3 HCs do not immediately increase connectivity with other cone types. Instead, H3 dendrites retract and re-extend to contact new ultraviolet cones. But, if regeneration is delayed or absent, blue-cone synaptogenesis increases and ectopic synapses are made with red and green cones. Thus, cues directing synapse specificity can be maintained following input loss, but only within a limited time period. Further, we postulate that signals from the major input that shape the H3 HC's wiring pattern during development persist to restrict miswiring after damage
Atlas of phenotypic, genotypic and geographical diversity present in the European traditional tomato
[EN] The Mediterranean basin countries are considered secondary centres of tomato diversification. However, information on phenotypic and allelic variation of local tomato materials is still limited. Here we report on the evaluation of the largest traditional tomato collection, which includes 1499 accessions from Southern Europe. Analyses of 70 traits revealed a broad range of phenotypic variability with different distributions among countries, with the culinary end use within each country being the main driver of tomato diversification. Furthermore, eight main tomato types (phenoclusters) were defined by integrating phenotypic data, country of origin, and end use. Genome-wide association study (GWAS) meta-analyses identified associations in 211 loci, 159 of which were novel. The multidimensional integration of phenoclusters and the GWAS meta-analysis identified the molecular signatures for each traditional tomato type and indicated that signatures originated from differential combinations of loci, which in some cases converged in the same tomato phenotype. Our results provide a roadmap for studying and exploiting this untapped tomato diversity.We thank Universitat Illes Balears, the Greek Gene Bank (GGB-NAGREF), Universita degli Studi Mediterranea Reggio Calabria, the CRB-Leg (INRA-GAFL)", the Genebank of CNR-IBBR (Bari, Italy) and ARCA 2010 for seed sharing. CNR-IBBR also acknowledges the seed donors, the Leibniz Institute of Plant Genetics and Crop Plant Research, Maria Cristina Patane (CNR-IBE, Catania, Italy) and La Semiorto Sementi SRL, as well as Mrs. Roberta Nurcato for technical assistance. IBMCP-UPV acknowledges Maurizio Calduch (ALCALAX) for technical assistance and Mario Fon for English grammar editing. This work was supported by European Commission H2020 research and innovation program through TRADITOM grant agreement No.634561, G2P-SOL, grant agreement No. 677379, and HARNESSTOM grant agreement No. 101000716. Clara Pons and Mariola Plazas are grateful to Spanish Ministerio de Ciencia e Innovacion for postdoctoral grants FJCI-2016-29118 and IJC2019-039091I/AEI/10.13039/501100011033; Joan Casals to a Serra Hunter Fellow at Universitat Politècnica de Catalunya.Pons Puig, C.; Casals, J.; Palombieri, S.; Fontanet, L.; Riccini, A.; Rambla Nebot, JL.; Ruggiero, A.... (2022). Atlas of phenotypic, genotypic and geographical diversity present in the European traditional tomato. Horticulture Research. 9:1-16. https://doi.org/10.1093/hr/uhac112116
Active behaviour during early development shapes glucocorticoid reactivity
TGlucocorticoids are the final effectors of the stress axis, with numerous targets in the central nervous system and the periphery. They are essential for adaptation, yet currently it is unclear how early life events program the glucocorticoid response to stress. Here we provide evidence that involuntary swimming at early developmental stages can reconfigure the cortisol response to homotypic and heterotypic stress in larval zebrafish (Danio rerio), also reducing startle reactivity and increasing spontaneous activity as well as energy efficiency during active behaviour. Collectively, these data identify a role of the genetically malleable zebrafish for linking early life stress with glucocorticoid function in later life
Midline Signalling Systems Direct the Formation of a Neural Map by Dendritic Targeting in the Drosophila Motor System
During embryonic development of the motor system of Drosophila, motorneurons target their dendrites to different regions along the body axis in response to midline guidance cues
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