High-order Discontinuous Galerkin Solutions of Internal Low-mach Number Turbulent Flows☆

Abstract In this work we apply the high-order Discontinuous Galerkin (DG) finite element method to internal low-Mach number turbulent flows. The method here presented is designed to improve the performance of the solution in the incompressible limit using an implicit scheme for the temporal integration of the compressible Reynolds Averaged Navier Stokes (RANS) equations. The per- formance of the scheme is demonstrated by solving a well-known test-case consisting of an abrupt axisymmetric expansion using various degrees of polynomial approximation. Computations with k–ω model are performed to assess the modelling capabilities, with high-order accurate DG discretizations of the RANS equations, in presence of non-equilibrium flow conditions

Well-Type Steady Flow in Strongly Heterogeneous Porous Media: An Experimental Study

Steady well-type flow was monitored in an aquifer that was artificially packed in order to reproduce a given, highly heterogeneous, statistical distribution of the log-conductivity Y. In particular, we focus on pumping tests carried out at 10 volumetric flow rates. The experimental arrangement was composed by a pumping well and several surrounding observation piezometers. The unique feature of this experimental study is that the high heterogeneity structure of Y is known fairly well. Thus, the study lends itself as a valuable tool to corroborate theoretical findings about flows driven by sources through porous formations, where the variance 2 (in the present study equal to 3.79) of Y is large. Besides discussing experimental findings, we tackle the crucial issue of upscaling the hydraulic conductivity in a well-flow configuration. In particular, we deal with the equivalent conductivity (EC) as that pertaining to a homogeneous (fictitious) medium which conveys the same volumetric flow rate of the real one, under the same boundary conditions. Hence, the EC can be identified straightforwardly by means of head measurements. Even if we show that the EC is a proper parameter to reproduce measurements, it is experimentally shown (in line with the theoretical results) to be position-dependent, and therefore, it cannot be regarded (unlike groundwater-type flow) as a formation’s property. This implies that the EC applies only to the configuration at stake. Then, we show that the EC, combined with a recent model of effective conductivity in well-flows through highly heterogeneous porous formation, leads to a reasonably reliable estimate of 2 , some limitations and approximations, notwithstanding. It is hoped that the present experimental study will be useful for other researchers who are engaged with similar research-topics

Scaling analysis of water retention curves: a multi-fractal approach

Water retention curve (WRC) is analyzed by means of the fractal geometry approach. Three models accounting for the fractal distribution of either the pore and solid phase of unsaturated porous media have been considered. By using data collected during a field scale internal drainage, we determine the functional relationship between the WRC, and the fractal dimension(s). In particular, it is shown that the fractal scaling of the WRC is feasible provided that a large enough set of measurements at the lowest water contents is available. (C) 2013 The Authors. Published by Elsevier B.V

A generalized Hamiltonian Constraint Operator in Loop Quantum Gravity and its simplest Euclidean Matrix Elements

We study a generalized version of the Hamiltonian constraint operator in nonperturbative loop quantum gravity. The generalization is based on admitting arbitrary irreducible SU(2) representations in the regularization of the operator, in contrast to the original definition where only the fundamental representation is taken. This leads to a quantization ambiguity and to a family of operators with the same classical limit. We calculate the action of the Euclidean part of the generalized Hamiltonian constraint on trivalent states, using the graphical notation of Temperley-Lieb recoupling theory. We discuss the relation between this generalization of the Hamiltonian constraint and crossing symmetry.Comment: 35 pp, 20 eps figures; minor corrections, references added; version to appear in Class. Quant. Gra

Insomnia in the Italian Population During Covid-19 Outbreak: A Snapshot on One Major Risk Factor for Depression and Anxiety

Objectives: One of the largest clusters of Covid-19 infections was observed in Italy. The population was forced to home confinement, exposing individuals to increased risk for insomnia, which is, in turn, associated with depression and anxiety. Through a cross-sectional online survey targeting all Italian adult population (≥18 yrs), insomnia prevalence and its interactions with relevant factors were investigated. Methods: The survey was distributed from 1st April to 4th May 2020. We collected information on insomnia severity, depression, anxiety, sleep hygiene behaviors, dysfunctional beliefs about sleep, circadian preference, emotion regulation, cognitive flexibility, perceived stress, health habits, self-report of mental disorders, and variables related to individual difference in life changes due to the pandemic's outbreak. Results: The final sample comprised 1,989 persons (38.4 ± 12.8 yrs). Prevalence of clinical insomnia was 18.6%. Results from multivariable linear regression showed that insomnia severity was associated with poor sleep hygiene behaviors [β = 0.11, 95% CI (0.07–0.14)]; dysfunctional beliefs about sleep [β = 0.09, 95% CI (0.08–0.11)]; self-reported mental disorder [β = 2.51, 95% CI (1.8–3.1)]; anxiety [β = 0.33, 95% CI (0.25–0.42)]; and depression [β = 0.24, 95% CI (0.16–0.32)] symptoms. Conclusion: An alarming high prevalence of clinical insomnia was observed. Results suggest that clinical attention should be devoted to problems of insomnia in the Italian population with respect to both prevention and treatment

Relativistic effects and primordial non-Gaussianity in the galaxy bias

When dealing with observables, one needs to generalize the bias relation between the observed galaxy fluctuation field to the underlying matter distribution in a gauge-invariant way. We provide such relation at second-order in perturbation theory adopting the local Eulerian bias model and starting from the observationally motivated uniform-redshift gauge. Our computation includes the presence of primordial non-Gaussianity. We show that large scale-dependent relativistic effects in the Eulerian bias arise independently from the presence of some primordial non-Gaussianity. Furthermore, the Eulerian bias inherits from the primordial non-Gaussianity not only a scale-dependence, but also a modulation with the angle of observation when sources with different biases are correlated.Comment: 12 pages, LaTeX file; version accepted for publication in JCA

Te.M.P.O., an app for using temporal musical mismatch in post-stroke neurorehabilitation: a preliminary randomized controlled study

BACKGROUND: Recently, the potential rehabilitation value of music has been examined and music-based interventions and techniques such as the Negative Mismatch (MMN) have been increasingly investigated in the neurological rehabilitation context. OBJECTIVE: The aim of this study was to investigate the effectiveness of a negative mismatch-based therapy on the disability and quality of life in patients with stroke in sub-acute phase. METHODS: Thirty patients with a stroke diagnosis in sub-acute phase were randomly assigned to one of two groups: Mismatch (Mg) or Control (CTRLg) group. Both groups used an innovative Android application: Temporal Musical Patterns Organisation (Te.M.P.O). The Disability Rating Scale (DRS), the Modified Barthel Index (MBI) and the Stroke Specific Quality of Life scale (SSQoL) were used at the baseline (T0) and after four weeks of training (T1), in order to assess changes over time. RESULTS: Statistical analysis was performed using the data of 24 (Mg = 12, CTRLg = 12) subjects. The results show a major improvement of the Mg with respect to the CTRLg in all clinical scales score. CONCLUSION: The temporal negative mismatch-based therapy performed with the Te.M.P.O. application could be useful in improving the disability and the quality of life in stroke survivors in a sub-acute phase

The association between diurnal sleep patterns and emotions in infants and toddlers attending nursery

Background: Childcare programs often include mandatory naptime during the day. Loss of daytime sleep could lead to a moderate-to-large decrease in self-regulation, emotion processing, and learning in early childhood. Nevertheless, daytime sleep has been less accurately studied than nighttime sleep. This study aims to explore the relationship between diurnal sleep habits in nursery settings, nocturnal sleep quality, and post-nap emotional intensity in infants and toddlers. Methods: Data of 92 children (52 girls, 40 boys) aged 6 to 36 months were obtained. Sleep habits as well as positive and negative emotions were monitored by educators during nursery times through a sleep and emotion diary for two weeks. Results: Explorative analyses showed that diurnal sleep hours decreased across age groups (except for females aged 25–36 months) and that all age groups had a lower amount of nocturnal sleep than is recommended by the National Sleep Foundation. Partial correlation analysis showed significant correlation between daytime sleep onset latency and positive emotions. Mediation analyses showed that daytime napping is relevant for emotional functioning independently of nocturnal sleep quality. Conclusions: Daytime sleep in early childhood seems to be linked to the management of positive and negative emotions and could play a role in healthy development of emotional processes