344 research outputs found
Extending relative entropy for Korteweg-type models with non-monotone pressure: large friction limit and weak-strong uniqueness
No full textIn this paper we study weak-strong uniqueness and singular relaxation limits for the Euler–Korteweg and Navier–Stokes–Korteweg systems with non-monotone pressure. Both weak-strong uniqueness and the relaxation limit are investigated using relative entropy technique. We make use of the enlarged formulation of the model in terms of the drift velocity introduced in [Bresch, D. et al., Arch. Ration. Mech. Anal., 233(3):975–1025, 2019], generalizing in this way results proved in [Lattanzio, C. et al. Commun. Part. Diff. Eqs., 42(2):261–290, 2017] for the Euler–Korteweg model, by allowing more general capillarity functions, and the result contained in [Cianfarani Carnevale, G. et al. J. Diff. Eqs., 269, 2020] for the monotone pressure case
Insulin sensitivity in children born small for gestational age (SGA)
No full textshown a relationship between intrauterine growth retardation
and insulin resistance, type 2 diabetes and cardiovascular
disease in adulthood. Although the biological mechanisms
underlying this association are still largely unknown,
different explanatory hypotheses have been proposed. It
seems likely that the various pathways may interact with
each other, all contributing at different degrees to the development
of the metabolic disturbance
Laboratory tests and measurements in children born small for gestational age (SGA)
No full textChildren born small for gestational age are at high risk of developing insulin resistance, type 2 diabetes, hyperlipidemia, hypertension and cardiovascular disease in adulthood. In addition, approximately 10% of SGA children do not achieve a normal adult height. Studies performed in SGA children to evaluate markers of metabolic disease in prepubertal, pubertal and adolescent subjects, indicate a higher prevalence of subtle endocrine and metabolic abnormalities that may precede the onset of overt disease in adulthood. At present, however, there are no conclusive data supporting the need of systematic close monitoring of GH-IGF, hypothalamus-pituitary-adrenal and hypothalamus-pituitary-gonadal axes, as well as insulin sensitivity, glucose homeostasis, and lipid metabolism. Monitoring of metabolic parameters should probably be reserved to SGA children with genetic predisposition to type 2 diabetes and hyperlipidemia, as early identification of metabolic alterations might prompt effective preventive interventions and, ultimately, reduce cardiovascular risk. © 2005 Elsevier B.V. All rights reserved
Path-oriented early reaction to approaching disruptions in ASDEX Upgrade and TCV in view of the future needs for ITER and DEMO
No full textRoutine reaction to approaching disruptions in tokamaks is currently largely limited to machine protection by mitigating an ongoing disruption, which remains a basic requirement for ITER and DEMO [1]. Nevertheless, a mitigated disruption still generates stress to the device. Additionally, in future fusion devices, high-performance discharge time itself will be very valuable. Instead of reacting only on generic features, occurring shortly before the disruption, the ultimate goal is to actively avoid approaching disruptions at an early stage, sustain the discharges whenever possible and restrict mitigated disruptions to major failures. Knowledge of the most relevant root causes and the corresponding chain of events leading to disruption, the disruption path, is a prerequisite. For each disruption path, physics-based sensors and adequate actuators must be defined and their limitations considered. Early reaction facilitates the efficiency of the actuators and enhances the probability of a full recovery. Thus, sensors that detect potential disruptions in time are to be identified. Once the entrance into a disruption path is detected, we propose a hierarchy of actions consisting of (I) recovery of the discharge to full performance or at least continuation with a less disruption-prone backup scenario, (II) complete avoidance of disruption to sustain the discharge or at least delay it for a controlled termination and, (III), only as last resort, a disruption mitigation. Based on the understanding of disruption paths, a hierarchical and path-specific handling strategy must be developed. Such schemes, testable in present devices, could serve as guidelines for ITER and DEMO operation. For some disruption paths, experiments have been performed at ASDEX Upgrade and TCV. Disruptions were provoked in TCV by impurity injection into ELMy H-mode discharges and in ASDEX Upgrade by forcing a density limit in H-mode discharges. The new approach proposed in this paper is discussed for these cases. For the H-mode density limit sensors used so far react too late. Thus a plasma-state boundary is proposed, that can serve as an adequate early sensor for avoiding density limit disruptions in H-modes and for recovery to full performance. © 2017 Max-Planck-Institut for Plasmaphysics
Diabete insipido e sindrome da inappropriata secrezione di ormone antidiurerico “Diabetes insipidus and sindrome of inappropriate antidiuretic hormone SIADH”.
No full textHormonal regulation of postnatal growth in children born small for gestational age
No full textChildren born small for gestational age (SGA) are at high
risk of permanent short stature, with approximately 10%
continuing to have stature below the third centile
throughout childhood and adolescence and into adulthood.
The mechanisms involved in catch-up growth, and
those that prevent catch-up growth, are still unknown.
To date, no reliable anthropometric or endocrine parameter
predictive of postnatal catch-up growth has been
identifi ed. However, subtle abnormalities in the growth
hormone-insulin-like growth factor axis, the hypothalamic-
pituitary-adrenal axis and thyroid function have
been described, and a mechanism involving intrauterine
programming of hypothalamic-pituitary function has
been proposed
High friction limit for Euler–Korteweg and Navier–Stokes–Korteweg models via relative entropy approach
No full textThe aim of this paper is to investigate the singular relaxation limits for the Euler–Korteweg and the Navier–Stokes–Korteweg system in the high friction regime. We shall prove that the viscosity term is present only in higher orders in the proposed scaling and therefore it does not affect the limiting dynamics, and the two models share the same equilibrium equation. The analysis of the limit is carried out using the relative entropy techniques in the framework of weak, finite energy solutions of the relaxation models converging toward smooth solutions of the equilibrium. The results proved here take advantage of the enlarged formulation of the models in terms of the drift velocity introduced in [6], generalizing in this way the ones proved in [15] for the Euler–Korteweg model
Programming, metabolic syndrome, and NAFLD: The challenge of transforming a vicious cycle into a virtuous cycle
No full textn
Adipose Tissue: a Metabolic Regulator. Potential Implications for the Metabolic Outcome of Subjects Born Small for Gestational Age (SGA).
No full textAdipose tissue is involved in the regulation of glucose and
lipid metabolism, energy balance, inflammation and immune
response. Abdominal obesity plays a key role in the development
of insulin resistance because of the high lipolytic
rate of visceral adipose tissue and its secretion of adipocytokines.
Low birth weight subjects are prone to central redistribution
of adipose tissue and are at high risk of developing
metabolic syndrome, type 2 diabetes and cardiovascular disease.
Intrauterine adipogenesis may play a key role in the
fetal origin of the pathogenesis of metabolic syndrome, type
2 diabetes and cardiovascular disease. Therefore, knowledge
of the behavior of visceral adipose tissue-derived stem cells
could provide a greater understanding of the metabolic risk
related to intrauterine growth retardation, with potential
clinical implications for the prevention of long-term metabolic
alterations
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