451 research outputs found
The role of dark matter in the galaxy mass-size relationship
The observed relationship between stellar mass and effective radius for early
type galaxies, pointed out by many authors, is interpreted in the context of
Clausius' virial maximum theory. In this view, it is strongly underlined that
the key of the above mentioned correlation is owing to the presence of a deep
link between cosmology and the existence of the galaxy Fundamental Plane. Then
the ultimate meaning is: understanding visible mass - size correlation and/or
Fundamental Plane means understanding how galaxies form. The mass - size
relationship involves baryon (mainly stellar) mass and its typical dimension
related to the light, but it gets memory of the cosmological mass variance at
the equivalence epoch. The reason is that the baryonic component virializes by
sharing virial energy in about equal amount between baryons and dark matter,
this sharing depending, in turn, on the steepness of the dark matter
distribution. The general strategy consists in using the two-component tensor
virial theorem for determining the virialized baryonic configurations. A King
and a Zhao density profile are assumed for the inner baryonic and the outer
dark matter component, respectively, at the end of the relaxation phase. All
the considerations are restricted to spherical symmetry for simplicity. The
effect of changing the dark-to-baryon mass ratio, m, is investigated inside a
LambdaCDM scenario. A theoretical mass - size relation is expressed for the
baryonic component, which fits fairly well to the data from a recently studied
galaxy sample. Finally, the play of intrinsic dispersion on the mass ratio, m,
is discussed in the light of the cusp/core problem and some consequences are
speculated about the existence of a limit, m_l, expected by the theory.Comment: 36 pages, 8 figures (Accepted for publication in New Astronomy
On the tilt of Fundamental Plane by Clausius' virial maximum theory
The theory of the Clausius' virial maximum to explain the Fundamental Plane
(FP) proposed by Secco (2000, 2001,2005) is based on the existence of a maximum
in the Clausius' Virial (CV) potential energy of a early type galaxy (ETG)
stellar component when it is completely embedded inside a dark matter (DM)
halo. At the first order approximation the theory was developed by modeling the
two-components with two cored power-law density profiles. An higher level of
approximation is now taken into account by developing the same theory when the
stellar component is modeled by a King-model with a cut-off. Even if the DM
halo density remains a cored power law the inner component is now more
realistic for the ETGs. The new formulation allows us to understand more deeply
what is the dynamical reason of the FP tilt and in general how the CV theory
may really be the engine to produce the FP main features. The degeneracy of FP
in respect to the initial density perturbation spectrum may be now full
understood in a CDM cosmological scenario. A possible way to compare the FPs
predicted by the theory with those obtained by observations is also
exemplified.Comment: 35 pages, 8 figure
Is it possible to make a diagnosis of raw, heated and baked egg allergy in children using cut-offs? A systematic review
The diagnosis of IgE-mediated egg allergy lies both on a compatible clinical history and on the results of skin prick tests (SPTs) and IgEs levels. Both tests have good sensitivity but low specificity. For this reason, oral food challenge (OFC) is the ultimate gold standard for the diagnosis. The aim of the present paper is to systematically review the literature in order to identify, analyze and synthesize the predictive value of SPT and specific IgEs both to egg white and main egg allergens and to review the cut-offs suggested in the literature
Toward Understanding the origin of the Fundamental Plane for Early-Type Galaxies
We present a panoramic review of several observational and theoretical
aspects of the modern astrophysical research about the origin of the
Fundamental Plane (FP) relation for Early-Type Galaxies (ETGs). The discussion
is focused on the problem of the tilt and the tightness of the FP, and on the
attempts to derive the luminosity evolution of ETGs with redshift. Finally, a
number of observed features in the FP are interpreted from the standpoint of a
new theoretical approach based on the two-component tensor virial theorem.Comment: 30 pages, 3 figure
Vitamin D and rheumatic diseases.
Vitamin D has some well-known effects on calcium, phosphate and bone metabolism, but it has recently shown to have many other effects, which may potentially be relevant to patients with extra-skeletal rheumatic diseases. Such effects may be justified by: 1) the presence of the vitamin D receptors also on extra-osseous cells, such as cartilage cells, sinoviocytes, muscle cells; 2) the proven role of vitamin D in the control of the transcription of genes involved in rheumatic diseases; 3) the evidence that vitamin D has multiple endocrine effects not only on calcium homeostasis; 4) the activation of vitamin D not only in the kidneys, but also in monocyte-macrophage and lymphocytic cell lines and in some epithelial cells with additional intracrine and paracrine effects. Vitamin D deficiency has been reported in numerous metabolic, degenerative, inflammatory and autoimmune rheumatic diseases. In some cases this association was also related to the risk of developing a rheumatic disease or the degree of disease activity. However there is no conclusive evidence of the efficacy of a preventive or therapeutic strategy based on vitamin D supplementation in extra-skeletal rheumatic diseases. This review aims to provide an overview of the latest evidence concerning the relationship between vitamin D and the most relevant rheumatic diseases
Role of air pollutants mediated oxidative stress in respiratory diseases
Airborne particulate (PM) components from fossil fuel combustion can induce oxidative stress initiated by reactive oxygen species (ROS) that are strongly correlated with airway inflammation and asthma. A valid biomarker of airway inflammation is fractionated exhaled nitric oxide (FENO). The oxidative potential of PM2.5 can be evaluated with the dithiothreitol (DTT) dosage, which represents both ROS chemically produced and intracellular ROS of macrophages. This correlates with quality indicators of the internal environment and ventilation strategies such as dilution and removal of airborne contaminants
J-Integral Calculation by Finite Element Processing of Measured Full-Field Surface Displacements
© 2017 The Author(s)A novel method has been developed based on the conjoint use of digital image correlation to measure full field displacements and finite element simulations to extract the strain energy release rate of surface cracks. In this approach, a finite element model with imported full-field displacements measured by DIC is solved and the J-integral is calculated, without knowledge of the specimen geometry and applied loads. This can be done even in a specimen that develops crack tip plasticity, if the elastic and yield behaviour of the material are known. The application of the method is demonstrated in an analysis of a fatigue crack, introduced to an aluminium alloy compact tension specimen (Al 2024, T351 heat condition)
BUILDING BRIDGES FOR INNOVATION IN AGEING : SYNERGIES BETWEEN ACTION GROUPS OF THE EIP ON AHA
The Strategic Implementation Plan of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA) proposed six Action Groups. After almost three years of activity, many achievements have been obtained through commitments or collaborative work of the Action Groups. However, they have often worked in silos and, consequently, synergies between Action Groups have been proposed to strengthen the triple win of the EIP on AHA. The paper presents the methodology and current status of the Task Force on EIP on AHA synergies. Synergies are in line with the Action Groups' new Renovated Action Plan (2016-2018) to ensure that their future objectives are coherent and fully connected. The outcomes and impact of synergies are using the Monitoring and Assessment Framework for the EIP on AHA (MAFEIP). Eight proposals for synergies have been approved by the Task Force: Five cross-cutting synergies which can be used for all current and future synergies as they consider overarching domains (appropriate polypharmacy, citizen empowerment, teaching and coaching on AHA, deployment of synergies to EU regions, Responsible Research and Innovation), and three cross-cutting synergies focussing on current Action Group activities (falls, frailty, integrated care and chronic respiratory diseases).Peer reviewe
ARIA 2016:Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle
The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma and rhinitis and (3) to develop guidelines with all stakeholders that could be used globally for all countries and populations. ARIA-disseminated and implemented in over 70 countries globally-is now focusing on the implementation of emerging technologies for individualized and predictive medicine. MASK [MACVIA (Contre les Maladies Chroniques pour un Vieillissement Actif)-ARIA Sentinel NetworK] uses mobile technology to develop care pathways for the management of rhinitis and asthma by a multi-disciplinary group and by patients themselves. An app (Android and iOS) is available in 20 countries and 15 languages. It uses a visual analogue scale to assess symptom control and work productivity as well as a clinical decision support system. It is associated with an inter-operable tablet for physicians and other health care professionals. The scaling up strategy uses the recommendations of the European Innovation Partnership on Active and Healthy Ageing. The aim of the novel ARIA approach is to provide an active and healthy life to rhinitis sufferers, whatever their age, sex or socio-economic status, in order to reduce health and social inequalities incurred by the disease
ARIA 2016: Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle
The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma a
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