Present and future trajectories towards a possible valid and useful diagnosis of ADHD

To date, diagnosing Attention Defi cit Hyperactivity Disorder remains indeed one of the most controversial issues in contemporary psychiatry and behavioural sciences. Most of the conceptual problems regarding the validity of this diagnostic category arise from the heterogeneity of syndromal pictures and the high rate of comorbidity observed in subjects diagnosed with ADHD at all stages of the longitudinal course of the disorder. In this regard, DSM 5 increased complexity by allowing a diagnosis of comorbidity between ADHD and autism spectrum disorders while these two diagnoses were mutually exclusive in DSM-IV-TR

Synergistic toxicity of some sulfonamide mixtures on Daphnia magna

In livestock farming, sulfonamides (SAs) are used prophylactically and simultaneously in large numbers of animals. Therefore, traces of these compounds, alone or in combination, have been repeatedly detected in the environment. Synergistic interactions among chemicals in such mixtures represent an area of concern for the regulatory authorities. In this study, the acute toxic effects of binary and ternary mixtures of SAs were evaluated in Daphnia magna, in order to verify whether, based on their individual toxicity, they jointly exert a larger effect than would be predicted by individual actions alone. First, following the Concentration Addition (CA) principle, some preliminary observations were made by testing a number of drug combinations with an expected 50% effect. Then, mixtures more recognised for their synergistic effect (four binary and two ternary) were assayed in a range of reducing concentrations. The data acquired were processed using CompuSyn software, which integrates the different shape of the curves obtained in calculating the Combination Index (CI) for the evaluation of synergistic effects. For binary mixtures, synergy was also evaluated using the curvilinear isobologram method for heterodynamic drugs. Results indicate that most of the selected mixtures exhibit a synergistic effect using the CI methodology. For binary mixtures, these findings were also confirmed by isobologram analysis. Detected synergies indicate that the CA is not always precautionary as a reference model for the evaluation of the aquatic toxicity of SAs mixtures

Effective viscosity of grease ice in linearized gravity waves

Grease ice is an agglomeration of disc-shaped ice crystals, named frazil ice, which forms in turbulent waters of the Polar Oceans and in rivers as well. It has been recognized that the properties of grease ice to damp surface gravity waves could be explained in terms of the effective viscosity of the ice slurry. This paper is devoted to the study of the dynamics of a suspension of disc-shaped particles in a gravity wave field. For dilute suspensions, depending on the strength and frequency of the external wave flow, two orientation regimes of the particles are predicted: a preferential orientation regime with the particles rotating in coherent fashion with the wave field, and a random orientation regime in which the particles oscillate around their initial orientation while diffusing under the effect of Brownian motion. For both motion regimes, the effective viscosity has been derived as a function of the wave frequency, wave amplitude and aspect ratio of the particles. Model predictions have been compared with wave attenuation data in frazil ice layers grown in wave tanks.Comment: 13 pages, 3 eps figures included; one more section on inertia effect

Slow dynamics in a primitive tetrahedral network model

We report extensive Monte Carlo and event-driven molecular dynamics simulations of the fluid and liquid phase of a primitive model for silica recently introduced by Ford, Auerbach and Monson [J. Chem. Phys. 17, 8415 (2004)]. We evaluate the iso-diffusivity lines in the temperature-density plane to provide an indication of the shape of the glass transition line. Except for large densities, arrest is driven by the onset of the tetrahedral bonding pattern and the resulting dynamics is strong in the Angell's classification scheme. We compare structural and dynamic properties with corresponding results of two recently studied primitive models of network forming liquids -- a primitive model for water and a angular-constraint free model of four-coordinated particles -- to pin down the role of the geometric constraints associated to the bonding. Eventually we discuss the similarities between "glass" formation in network forming liquids and "gel" formation in colloidal dispersions of patchy particles.Comment: 9 pages, 10 figure

Optical observations of acoustical radiation force effects on individual air bubbles

Previous studies dealing with contrast agent microbubbles have demonstrated that ultrasound (US) can significantly influence the movement of microbubbles. In this paper, we investigated the influence of the acoustic radiation force on individual air bubbles using high-speed photography. We emphasize the effects of the US parameters (pulse length, acoustic pressure) on different bubble\ud patterns and their consequences on the translational motion of the bubbles. A stream of uniform air bubbles with diameter ranging from 35 um to 79 um was generated and insonified with a single US pulse emitted at a frequency of 130 kHz. The bubble sizes have been chosen to be above, below, and at resonance. The peak acoustic pressures used in these experiments ranged from 40 kPa to 120 kPa. The axial displacements of the bubbles produced by the action of the US pulse were optically recorded using a high-speed camera at 1 kHz frame rate. The experimental results were compared to a simplified force balance theoretical model, including the action of the primary radiation force and the fluid drag force. Although the model is quite simple and does not take into account phenomena like bubble shape oscillations and added mass, the experimental findings agree with the predictions. The measured axial displacement increases quasilinearly with the burst length and the transmitted acoustic pressure. The axial displacement varies with the size and the density of the air bubbles, reaching a maximum at the resonance size of 48 um. The predicted displacement values differ by 15% from the measured data, except for resonant bubbles for which the displacement was overestimated by about 40%. This study demonstrates that even a single US pulse produces radiation forces that are strong enough to affect the bubble position

Routinization and Covid-19: a comparison between United States and Portugal

Earnings inequality has been increasing in Portugal and United States in the last 30years and with the recent pandemic outbreak this trend is likely to reach even higher levels. The purpose of this paper is to identify what is the role of automatization in increasing wage inequality, making a comparison between the two countries. Using PSID and Quadros de Pessoal, we find that labor income dynamics are strongly determined by the variance of the individual fixed component. This effect is drastically reduced by adding information on workers’ occupational tasks, confirming that decreasing price of capital and the consequent replacement of routine manual worker shave deepened wage inequality. During the current crisis, we find that the ability to keep working is strongly related with the occupation type. As such, we simulate the impact of a permanent demand shock using an overlapping-generations model with incomplete markets and heterogeneous agents to quantitatively predict the impact ofCovid-19 and lockdown measures on wage premium and earnings inequality. We find that wage premia and earnings dispersion increase, suggesting that earnings inequality will increase at the expenses of manual workers