4,005 research outputs found
Quasi-optimal mesh sequence construction through smoothed adaptive finite element methods
We propose a new algorithm for adaptive finite element methods (AFEMs) based on smoothing iterations (S-AFEM), for linear, second-order, elliptic partial differential equations (PDEs). The algorithm is inspired by the ascending phase of the V-cycle multigrid method: we replace accurate algebraic solutions in intermediate cycles of the classical AFEM with the application of a prolongation step, followed by the application of a smoother. Even though these intermediate solutions are far from the exact algebraic solutions, their a posteriori error estimation produces a refinement pattern that is substantially equivalent to the one that would be generated by classical AFEM, at a considerable fraction of the computational cost. We provide a qualitative analysis of how the error propagates throughout the algorithm, and we present a series of numerical experiments that highlight the efficiency and the computational speedup of S-AFEM
Quasi-optimal mesh sequence construction through Smoothed Adaptive Finite Element Methods
We propose a new algorithm for Adaptive Finite Element Methods (AFEMs) based on smoothing iterations (S-AFEM), for linear, second-order, elliptic partial differential equations (PDEs). The algorithm is inspired by the ascending phase of the V-cycle multigrid method: we replace accurate algebraic solutions in intermediate cycles of the classical AFEM with the application of a prolongation step, followed by a fixed number of few smoothing steps. Even though these intermediate solutions are far from the exact algebraic solutions, their a-posteriori error estimation produces a refinement pattern that is substantially equivalent to the one that would be generated by classical AFEM, at a considerable fraction of the computational cost. We quantify rigorously how the error propagates throughout the algorithm, and we provide a connection with classical a posteriori error analysis. A series of numerical experiments highlights the efficiency and the computational speedup of S-AFEM
The Importance of Nutrition in Hypertension
Arterial hypertension (AH) is considered to be one of the most relevant cardiovascular risk factors, and its wide prevalence in all age ranges makes it necessary to analyse all the possible causes and treatments. In this special issue, nutritional interventions are examined either as causes or as treatments of AH. [...]
Long walk to genomics : history and current approaches to genome sequencing and assembly
Genomes represent the starting point of genetic studies. Since the discovery of DNA structure, scientists have devoted great efforts to determine their sequence in an exact way. In this review we provide a comprehensive historical background of the improvements in DNA sequencing technologies that have accompanied the major milestones in genome sequencing and assembly, ranging from early sequencing methods to Next-Generation Sequencing platforms. We then focus on the advantages and challenges of the current technologies and approaches, collectively known as Third Generation Sequencing. As these technical advancements have been accompanied by progress in analytical methods, we also review the bioinformatic tools currently employed in de novo genome assembly, as well as some applications of Third Generation Sequencing technologies and high-quality reference genomes
The source and the age of the soil organic matter of Anthrosols in SW Norway
Recent investigations showed that humusârich topsoilâs around the Baltic Sea have been formed by the application of pyrogenic organic matter (Acksel et al., 2016, Geoderma Reg. 7, 187â200) and organic materials (e.g. animal manure, organic waste) linked with human activity and, consequently, these soils were classified as Anthrosols (Acksel et al., 2017 (submitted)). Such humusârich topsoilâs, which were strongly influenced by anthropogenic activities and classified as plaggic Anthrosols, were described in SW Norway (Schnepel et al., 2014, J. Plant Nutr. Soil Sci., 177 (4), 638â645.). However, the source and the formation time of the Anthrosols in Norway have not been investigated in detail. Therefore, we characterized the soil organic matter composition by pyrolysis-field ionisation-mass spectrometry (Py-FIMS), benzene polycarboxylic acids (BPCA) determination, examined the source of the SOM by isotopic signatures (d34S) and estimated the age of the SOM by 14C AMS dating in order to find out the beginning of Anthrosol formation. Py-FIMS revealed high portions of sterols and fatty acids, indicating inputs of manure, similar to plaggic Anthrosols in NW Germany. The BC portions (â 19 % BC of Corg) were similar to various Anthrosols (â 25 % BC of Corg) and Chernozems (â 13 % BC of Corg) worldwide and indicated an input of combustion residues to soils by early fire events. The d34S isotope signature of the SOM ranged from 10 to 13.4 â° at the islands and 10.6 to 15.2 in the Jaeren region of SW Norway, corresponded to the Anthrosols in the Baltic Sea region (Median: d34S = 11.5 â°) and indicated an input of marine biomass (d34S of seaweed = 20 â°). All these results complemented the study of Schnepel et al. (2014) and provided strong evidence that these soils were formed by human activities. Ongoing analyses of 14C ages from these soils enable to estimate the timing of the soil formation and link it to settlement history
The mediation of care and overprotection between parent-adolescent conflicts and adolescentsâ psychological difficulties during the pandemic: which role for fathers?
Background: There is evidence of a significant raise in youthsâ emotional and behavioral difficulties during the pandemic. Only a few studies have addressed parent-adolescent conflict, and none investigated the possible mediating effect of parenting in the association between conflicts with parents and adolescentsâ symptoms. This study aimed at investigating youthsâ psychological symptoms during the pandemic, focusing on the predicting effect of parent-adolescent conflict. The mediating role of care and overprotection was also explored, considering whether adolescent gender moderated this mediation. Methods: 195 adolescents aged 14â18 years participated in an online longitudinal study. Perceived conflict with parents and parenting dimensions (Parental Bonding Instrument; PBI) were assessed at baseline (2021). Self-reported psychological difficulties (Strengths and Difficulties Questionnaire; SDQ) were collected at baseline and after one year (2022). Results: A significantly severer symptomatology was found in adolescents having a conflictual relationship with one or both parents. Major conflicts with parents correlated with lower care and greater overprotection in mothers and fathers. However, parental overprotection and maternal care were not mediators of the relationship between conflict and youths' difficulties. The only exception was represented by paternal care that fully mediated this relationship in both adolescent males and females. Conclusions: Although further investigations are needed to overcome limitations due to the small sample, findings extend our insight into the impact of parent-adolescent conflict, highlighting the role of fathersâ care and the need to maximize their involvement in clinical interventions
The minimal N=4 no-scale model from generalized dimensional reduction
We consider the generalized dimensional reduction of pure ungauged N=4, D=5
supergravity, where supersymmetry is spontaneously broken to N=2 or N=0 with
identically vanishing scalar potential. We explicitly construct the resulting
gauged D=4 theory coupled to a single vector multiplet, which provides the
minimal N=4 realization of a no-scale model. We discuss its relation with the
standard classification of N=4 gaugings, extensions to non-compact twists and
to higher dimensions, the N=2 theories obtained via consistent Z_2 orbifold
projections and prospects for further generalizations.Comment: 1+28 pages, no figures, JHEP3 LaTeX, published versio
Efficacy of a U-shaped automatic electric toothbrush in dental plaque removal: A cross-over randomized controlled trial
GEANT4 low energy electromagnetic models for electrons and photons
A set of physics processes has been developed in the Geant4 Simulation Toolkit to describe the electromagnetic interactions of photons and electrons with matter down to 250 eV. Preliminary comparisons of the models with experimental data show a satisfactory agreement
Skin reactions triggered by the use of cosmetic products in nonspecific lipid transfer protein-sensitive patients.
Nonspecific lipid transfer proteins (nsLTPs) are members of the prolamine superfamily and they are found in pollen and food, as well as in latex. Due to the strong stability both against pepsin digestion and thermal denaturation, sensitisation towards these proteins is often associated with severe systemic reactions (angioedema, urticaria, asthma, anaphylaxis, etc.) following the ingestion of both raw or fresh food and cooked or preserved food. Many studies have shown reactivity towards nsLTPs both via inhalation and orally and in this study we present two cases of nsLTPs-sensitive patients who manifested the immediate onset of skin reactions following the use of cosmetic products containing these proteins. Thus, in order to prevent immediate reactions linked to their use, it is necessary to recommend nsLTPs-sensitive patients to avoid the topical use of products containing these proteins (and obviously the ingestion of foods containing these proteins)
- âŠ