226 research outputs found
The effects of vegetarian diets on bone health: a literature review
Get PDFIn these recent years many people are adopting a vegetarian type diet due to the numerous positive health effects of this regimen such as the reduction of the incidence of many chronic disorders like diabetes, hypertension, obesity and cancer. However this diet is quite restrictive and so it could be possible to have a deficiency in some specific nutrients, increasing the risk of osteoporosis and fractures. Although there are conflicting results on the effects of the vegetarian diet on bone health and fracture incidence, it is always recommendable in vegetarian people to have an adequate intake of calcium and vitamin D, through an increased intake of supplements, natural and fortified foods, an adequate intake of protein, fruit, vegetables, as well as vitamin B12. The aim of this literature review is to revise the actual knowledge of the effect of some nutrients and vegetarian diets on bone health. Copyright © 2022 Falchetti, Cavati, Valenti, Mingiano, Cosso, Gennari, Chiodini and Merlotti
Variable Selection in Additive Models by Nonnegative Garrote
Get PDFWe adapt Breiman's (1995) nonnegative garrote method to perform variable selection in nonparametric additive models. The technique avoids methods of testing for which no reliable distributional theory is available. In addition it removes the need for a full search of all possible models, something which is computationally intensive, especially when the number of variables is moderate to high. The method has the advantages of being conceptually simple and computationally fast. It provides accurate predictions and is effective at identifying the variables generating the model. For illustration, we consider both a study of Boston housing prices as well as two simulation settings. In all cases our methods perform as well or better than available alternatives like the Component Selection and Smoothing Operator (COSSO).cross-validation, nonnegative garrote, nonparametric regression, shrinkage methods, variable selection
l-->(l-l) Ag M4,5 XAS investigation at the Ag/Si(111)2x1 interface.
No full textWe have studied the evolution of the low-lying unoccupied Ag5p-derived electron states at the Ag/Si(111)2 x 1 interface as a function of the Ag coverage via (l --> (l - 1)) Ag M4,5 X-ray absorption spectroscopy. The measured line-shapes are discussed in terms of a transition of the overgrown adlayer from two- to three-dimensional character
An Adaptive Algorithm for Multipath Mitigation in GNSS Positioning with Android Smartphones
No full textWe present a solution for improving the robustness of GNSS positioning with Android devices. The proposed method combines an acquisition phase performed in a dedicated Android app (thus working on the edge) and a processing phase, based on a modified version of the open source library RTKLIB, performed on a dedicated server. The processing phase applies an improved version of the RTK library based on an adaptive algorithm for mitigating the multipath effect on satellite radio signals received by smartphone’s antennas. The algorithm is built on top of an extended version of the sigma-epsilon model in which weights associated to observables potentially affected by multipath errors are computed using logged data. In the paper, we will focus our attention on the architecture of the proposed solution and discuss preliminary experimental results obtained with the resulting system
State‐space approach for spmsm sensorless passive algorithm tuning
No full textSensorless algorithms for Permanent Magnet Synchronous Motors (PMSM) have achieved increasing interest in the technical literature over the last few years. They can be divided into active methods and passive methods: the first inject high‐frequency signals exploiting rotor anisotropy, whereas the second are based on observers. Recently, a sensorless control based on a rotor flux observer has been presented in the technical literature, which gives very accurate results in terms of rotor position estimation and robustness. In this paper, the aforementioned observer is considered and a procedure for choosing stabilizing gains of the observer is proposed. The contribution of the paper is three‐fold: the mathematical modelling of the rotor flux observer, the methodology for the definition of the observer gains, and the presentation of the experimental results
A fast control for a three-switch multi-input DC-DC converter
No full textIn this paper, a double-input bidirectional DC-DC converter is taken into account. The converter allows to use less switches than a traditional solution and, moreover, it guarantees a higher efficiency. The modulation strategy proposed in the technical literature allows the converter to work in Discontinuous Conduction Mode at low-load and, therefore, to increase the efficiency in comparison to the CCM. However, such a control reduces the dynamics of the converter. To improve the transient response, a Feed-Forward approach is proposed in this paper. Since the converter model in DCM is complex and highly nonlinear, a simplified model is considered. The effectiveness of the proposed approach is proved with experimental results on a converter prototype
Conversione statica di energia nella trasmissione HVDC
No full textQuesto articolo si pone l’obiettivo di presentare le principali caratteristiche di un collegamento HVDC e le sue diverse configurazioni, dopo una breve introduzione in merito alla storia e allo sviluppo di questa tecnologi
RESOLVING THE SURFACE CONTRIBUTION OF THE P L2, 3 VV AUGER LINESHAPE OF GAP(110) VIA USE OF (1 X-1) SB OVERLAYERS
No full textAn experimental and theoretical study of the band-like P L2,3VV Auger lineshape for GaP(110) is reported (kinetic energy almost-equal-to 120eV). By deposition of one monolayer of Sb (isoelectronic to P) we determine the surface-related Auger lineshape as the difference between the two spectra measured from the as-cleaved surface and the GaP/Sb interface. Theoretical calculations based on a single particle approach including different structural coordination models (i.e. ideally truncated surface, real relaxed surface, ordered Sb overlayer) are performed, which allows to isolate the surface contribution of the L2,3VV Auger profile from the bulk related lineshape. Moreover the results of the joint analysis are discussed giving excellent agreement between calculations and measurements and pointing toward an interpretation of the P LVV lineshape in terms of surface structural probe
EXPERIMENTAL AND THEORETICAL SURFACE COMPONENT OF THE PL2,3VV AUGER LINESHAPE IN GAP(110) - THE USE OF ORDERED (1X1) SB OVERLAYERS
No full textAn analysis of the theoretical and experimental surface contribution of the PL2,3VV Auger lineshape in GaP(110) is performed. From the theoretical point of view the lineshapes are calculated within a single-particle framework from a slab-by-slab tight-binding calculation of the ideal and real relaxed surfaces. The experimental information is extracted by comparing the Auger feature of as-cleaved GaP(110) and of the GaP(110) interfaced with one ordered monolayer of Sb. This allows the LVV surface component to be isolated. A comparison with theory, showing strong similarities in the position of the surface-related features is discussed
Fitness for service assessment of defected welded structural details by experimental evaluation of the fatigue resistance S-N curve
No full textDuring the fabrication of two different structures (a ship, a bridge) some unacceptable anomalies were
detected; the structures were almost completely fabricated and a repair of the defected structural
details was impractical, due to the extent of the defected zones.
As far as the ship was concerned the anomalies were represented by a large number of welded joints,
judged unacceptable according to the Design and Fabrication Code, while in the case of the bridge,
the anomalies were represented by planar flaws in the plates forming the girder web, subjected to outof-plane loads for effect of fillet welded connections of bracing.
A fitness for service assessment has therefore been carried out, in both cases, by performing fatigue
tests on representative samples, cut-off from the structure, and by evaluating the fatigue resistance
curve. A re-assessment of the structural details in question was undertaken, on the basis of the
experimental S-N curve, evaluating the fitness for service of the “defected details”.
The experimental program has also given the opportunity to compare different methodologies for
fatigue assessment: the Effective Notch Stress Method, the Fracture Mechanics Method and the Peak
Stress Method. The different procedures have been applied to the tested specimens, and the
expected fatigue life was compared with the experimental one
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