Mesh update techniques for free-surface flow solvers using spectral element method

This paper presents a novel mesh-update technique for unsteady free-surface Newtonian flows using spectral element method and relying on the arbitrary Lagrangian--Eulerian kinematic description for moving the grid. Selected results showing compatibility of this mesh-update technique with spectral element method are given

On Predicting The Turbulence-induced Secondary Flows Using Nonlinear K-∈ Models

Low turbulent Reynolds number direct simulation data are used to calculate the invariants of the Reynolds stress and the turbulent dissipation rate in a square duct. The results show that, depending on the region where the analysis is carried out, the turbulent flow field comes close to one-, two-, and three-component states. Modeling such flows - even at higher Reynolds numbers - will require models that can approach all three states. A number of related nonlinear k-∈ models are tested a priori using the direct simulation data. The numerical simulation using Reynolds averaged Navier-Stokes equations with these models was performed. Their ability to predict the secondary flows, with a low-Reynolds k-∈ model, cannot be gauged from realizability. © 1996 American Institute of Physics.8718561868Speziale, C.G., Analytical methods for the developments of Reynoldsstress closures in turbulence (1991) Annu. Rev. 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Fluid Mech., 233, p. 369Bradshaw, P., Blair Perot, J., A note on turbulent energy dissipation in viscous wall region (1993) Phys. Fluids, 5, p. 3305Kim, J., Moin, P., Moser, R., Turbulent statistics in fully developed channel flow at low Reynolds number (1987) J. Fluid Mech., 177, p. 133Tennekes, H., Lumley, J.L., (1972) A First Course in Turbulence, , MIT Press, Cambridge, MALumley, J.L., Computational Modeling of Turbulent Flows (1978) Advances in Applied Mechanics, 18, p. 123. , Academic Press. New YorkGavrilakis, S., Large-scale structures in the turbulent flow near a right-angled corner (1994) 1st ERCOFTAC Workshop on Direct and Large-Eddy Simulation, , SurreyGessner, F.B., The origin of secondary flow in turbulent flow along a corner (1973) J. Fluid Mech., 58, p. 1Speziale, C.G., The dissipation rate correlation and turbulent secondary flows in noncircular ducts (1986) Trans. Am. Soc. Mech. Eng. J. 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Three-dimensional flow instability in a lid-driven isosceles triangular cavity

Linear three-dimensional modal instability of steady laminar two-dimensional states developing in a lid-driven cavity of isosceles triangular cross-section is investigated theoretically and experimentally for the case in which the equal sides form a rectangular corner. An asymmetric steady two-dimensional motion is driven by the steady motion of one of the equal sides. If the side moves away from the rectangular corner, a stationary three-dimensional instability is found. If the motion is directed towards the corner, the instability is oscillatory. The respective critical Reynolds numbers are identified both theoretically and experimentally. The neutral curves pertinent to the two configurations and the properties of the respective leading eigenmodes are documented and analogies to instabilities in rectangular lid-driven cavities are discussed

Adjuvant formulation for veterinary vaccines: Montanide™ Gel safety profile

AbstractSelecting the adjuvant is one of the key for the success of the vaccine in the field. Selecting a flexible adjuvant that will fit with several vaccines dedicated to one or more animal species is a source of economical efficiency. Frequently the safety or efficacy obtained with one model is different from another: there are few adjuvants fitting with the expectation of more than one animal species. Montanide™ Gel an innovative polymeric adjuvant have been tested in several animals. Our studies demonstrated the ability to use this adjuvant in dogs, cattle and pig vaccines. Three trials were performed to validate Montanide™ Gel ability to be used in cattle, pigs and dogs. Respectively, vaccines were formulated with ovalbumin in cattle, Pasteurella Multocida anatoxin and Bordetella bronchiseptica cell walls for pig and finally with parvovirus associated to two leptospira valence for dog model. All antigenic media used in the three trials were inactivated. In all trial, safety was followed through behaviour and temperature measurement as well as histology studies.Montanide™ Gel adjuvant can be used associated with a wide range of antigenic media. Nevertheless, the uses of such adjuvant need validation in avian and fish vaccines

Dynamics on Networks of Manifolds

We propose a precise definition of a continuous time dynamical system made up of interacting open subsystems. The interconnections of subsystems are coded by directed graphs. We prove that the appropriate maps of graphs called graph fibrations give rise to maps of dynamical systems. Consequently surjective graph fibrations give rise to invariant subsystems and injective graph fibrations give rise to projections of dynamical systems

Always on my mind: Cross-brain associations of mental health symptoms during simultaneous parent-child scanning.

How parents manifest symptoms of anxiety or depression may affect how children learn to modulate their own distress, thereby influencing the children's risk for developing an anxiety or mood disorder. Conversely, children's mental health symptoms may impact parents' experiences of negative emotions. Therefore, mental health symptoms can have bidirectional effects in parent-child relationships, particularly during moments of distress or frustration (e.g., when a parent or child makes a costly mistake). The present study used simultaneous functional magnetic resonance imaging (fMRI) of parent-adolescent dyads to examine how brain activity when responding to each other's costly errors (i.e., dyadic error processing) may be associated with symptoms of anxiety and depression. While undergoing simultaneous fMRI scans, healthy dyads completed a task involving feigned errors that indicated their family member made a costly mistake. Inter-brain, random-effects multivariate modeling revealed that parents who exhibited decreased medial prefrontal cortex and posterior cingulate cortex activation when viewing their child's costly error response had children with more symptoms of depression and anxiety. Adolescents with increased anterior insula activation when viewing a costly error made by their parent had more anxious parents. These results reveal cross-brain associations between mental health symptomatology and brain activity during parent-child dyadic error processing

TEAMwork: Testing Emotional Attunement and Mutuality During Parent-Adolescent fMRI.

The parent-child relationship and family context influence the development of emotion regulation (ER) brain circuitry and related skills in children and adolescents. Although both parents' and children's ER neurocircuitry simultaneously affect how they interact with one another, neuroimaging studies of parent-child relationships typically include only one member of the dyad in brain imaging procedures. The current study examined brain activation related to parenting and ER in parent-adolescent dyads during concurrent fMRI scanning with a novel task - the Testing Emotional Attunement and Mutuality (TEAM) task. The TEAM task includes feedback trials indicating the other dyad member made an error, resulting in a monetary loss for both participants. Results indicate that positive parenting practices as reported by the adolescent were positively correlated with parents' hemodynamic activation of the ventromedial prefrontal cortex, a region related to empathy, during these error trials. Additionally, during feedback conditions both parents and adolescents exhibited fMRI activation in ER-related regions, including the dorsolateral prefrontal cortex, anterior insula, fusiform gyrus, thalamus, caudate, precuneus, and superior parietal lobule. Adolescents had higher left amygdala activation than parents during the feedback condition. These findings demonstrate the utility of dyadic fMRI scanning for investigating relational processes, particularly in the parent-child relationship

When Madagascar produced natural rubber: a brief, forgotten yet informative history.

From 1891 to 1914, Madagascar, like other western African countries, was a production zone for forest rubber destined for export to Europe when Asian plantations where not yet sufficiently developed . Numerous species endemic to the forests of the three major Malagasy ecosystems were exploited, often with a view to maximising short term productivity without any consideration for the sustainable management of the resource. This episode represents one of the first cases of industrial exploitation of Madagascar's biological resources. Although Madagascar occupies a modest position on the world rubber market at that time, the exploitation of rubber bore major consequences for the island's forestry resources and, moreover, influenced the vision and discourse of scientists and politicians concerning their management. It was one of the factors triggering awareness of the value of Madagascar's biodiversity and the threat to which it might be exposed through poorly-controlled human activity. As a result, highly repressive and forcible legislation was introduced aimed at containing the activity practiced by local populations considered to be mostly to blame. But from the early days of French colonial rule, naturalists judged the outcomes of political decisions too weak to offer any guarantee of an effective defence. They responded by adopting an intentionally alarmist and catastrophist discourse with the object of provoking a reaction from the politicians, considered too lax. This discourse, in fact, took an about-turn from 1942-45 when the war effort led to a revitalisation of the Malagasy rubber sector as Asian production was mainly out of reach. A second consequence came in 1927 with the creation of a network of protected areas managed by naturalists, making Madagascar at that time, a pioneer in Africa. There was a simultaneous flurry of activity to promote the domestication of Malagasy rubber species, combined with the introduction of new species with high potential (Hevea brasiliensis, Castilloa elastica). However, with the emergence of far more profitable Asian rubber, all attempts at cultivation in Madagascar were abandoned when exploitation ceased to be profitable, and thus the Malagasy forests were redeemed. This episode demonstrates how it was in fact economic reality, by condemning an unprofitable sector, that was the real vehicle by which the survival of Malagasy rubber species was secured, and not the naturalists' discourse, nor the creation of protected zones, nor the promulgation of repressive legislations. This case study is of more than purely historical interest, in that it still has currency where, for example, the exploitation of Prunus africana is concerned

Polyproline is a minimal antifreeze protein mimetic and enhances the cryopreservation of cell monolayers

Tissue engineering, gene therapy, drug screening and emerging regenerative medicine therapies are fundamentally reliant on high-quality adherent cell culture, but current methods to cryopreserve cells in this format can give low cell yields and requires large volumes of solvent 'antifreezes'. Herein we report polyproline is a minimum (bio)synthetic mimic of antifreeze proteins, which is accessible by solution, solid phase and recombinant methods. We demonstrate that polyproline has ice recrystallization inhibition activity linked to its amphipathic helix and that it enhances the DMSO- cryopreservation of adherent cell lines. Polyproline may be a versatile additive in the emerging field of macromolecular cryoprotectants