Investigating the Effects of a Parent-Mediated Intervention on Latino Parent-Child Verbal Interaction and Children\u27s Receptive Vocabulary

This study aimed to investigate parent-child verbal interactions in Spanish in a group of Latino preschoolers growing up in the United States through a parent-mediated program at home, and the effects of the program on their receptive vocabulary in Spanish. A single subject multiple baseline across participants design was used in the study. The participants were 3 Latino mothers and their sons, with low family income, living in the United States. The intervention taught the mothers strategies to enhance their children’s language through a sharing-book activity. The study lasted for 6 weeks during which baseline and intervention conditions data were collected through videotapes of the Dyads’ mealtimes. The results of the study showed that their verbal interactions were functional, brief, and typically not extended to children’s activities. The number of verbal interactions increased for 2 of the 3 Dyads from baseline to intervention condition and decreased for 1 of them. The children’s receptive vocabulary and school readiness skills increased after the intervention as showed by pre and post intervention assessments. The social validity survey suggested that Latina mothers found the project beneficial since, it not only increased their children’s interest in books, but also their own motivation to share books with them. Research and practical implications were discussed

Modulational instability, wave breaking and formation of large scale dipoles in the atmosphere

In the present Letter we use the Direct Numerical Simulation (DNS) of the Navier-Stokes equation for a two-phase flow (water and air) to study the dynamics of the modulational instability of free surface waves and its contribution to the interaction between ocean and atmosphere. If the steepness of the initial wave is large enough, we observe a wave breaking and the formation of large scale dipole structures in the air. Because of the multiple steepening and breaking of the waves under unstable wave packets, a train of dipoles is released and propagate in the atmosphere at a height comparable with the wave length. The amount of energy dissipated by the breaker in water and air is considered and, contrary to expectations, we observe that the energy dissipation in air is larger than the one in the water. Possible consequences on the wave modelling and on the exchange of aerosols and gases between air and water are discussed

Board characteristics and financial performance in the insurance industry: An international empirical survey

There are few studies in the literature on how the characteristics of boards of directors affect the performance of insurance companies. The purpose of this research is to investigate the characteristics of a company’s board that can have a significant impact on financial performance in the insurance sector. For this purpose, we performed a dynamic pooled regression model to test the impact of a wide range of board-specific factors. The survey has been conducted on an international sample of 119 listed insurance companies operating in the period 2009-2019. The sample includes companies from three geographical areas: North America, Europe and Asia. Our findings provide evidence that board structure and board independence are the most relevant governance factors, with a potentially positive impact on insurers’ market performance. These findings indirectly outline the opportunity for insurance companies to improve corporate fair value by strengthening internal governance models through effective board policies, an adequate qualification of board members and a well-balanced membership of the board. At the same time, there is still room for improvement as regards the level of board independence by strengthening internal governance policies in order to maintain an adequate number of independent and non-executive board members. The study upgrades the evidence arising from the existing literature by providing new elements to support a deeper understanding of the effects of insurance companies’ board characteristics on financial performance. Empirical results may also have important implications for both managers and policy makers

Correlated Nanoscopic Josephson Junctions

We discuss correlated lattice models with a time-dependent potential across a barrier and show how to implement a Josephson-junction-like behavior. The pairing occurs by a correlation effect enhanced by the symmetry of the system. In order to produce the effect we need a mild distortion which causes avoided crossings in the many-body spectrum. The Josephson-like response involves a quasi-adiabatic evolution in the time-dependent field. Besides, we observe an inverse-Josephson (Shapiro) current by applying an AC bias; a supercurrent in the absence of electromotive force can also be excited. The qualitative arguments are supported by explicit exact solutions in prototype 5-atom clusters with on-site repulsion. These basic units are then combined in ring-shaped systems, where one of the units sits at a higher potential and works as a barrier. In this case the solution is found by mapping the low-energy Hamiltonian into an effective anisotropic Heisenberg chain. Once again, we present evidence for a superconducting flux quantization, i.e. a Josephson-junction-like behavior suggesting the build-up of an effective order parameter already in few-electron systems. Some general implications for the quantum theory of transport are also briefly discussed, stressing the nontrivial occurrence of asymptotic current oscillations for long times in the presence of bound states.Comment: 12 pages, 2 figures, to appear in J. Phys. - Cond. Ma

Suppression of electron-electron repulsion and superconductivity in Ultra Small Carbon Nanotubes

Recently, ultra-small-diameter Single Wall Nano Tubes with diameter of $\sim 0.4 nm$ have been produced and many unusual properties were observed, such as superconductivity, leading to a transition temperature $T_c\sim 15^oK$, much larger than that observed in the bundles of larger diameter tubes. By a comparison between two different approaches, we discuss the issue whether a superconducting behavior in these carbon nanotubes can arise by a purely electronic mechanism. The first approach is based on the Luttinger Model while the second one, which emphasizes the role of the lattice and short range interaction, is developed starting from the Hubbard Hamiltonian. By using the latter model we predict a transition temperature of the same order of magnitude as the measured one.Comment: 7 pages, 3 figures, to appear in J. Phys.-Cond. Ma

Measuring surface gravity waves using a Kinect sensor

We present a technique for measuring the two-dimensional surface water wave elevation both in space and time based on the low-cost Microsoft Kinect sensor. We discuss the capabilities of the system and a method for its calibration. We illustrate the application of the Kinect to an experiment in a small wave tank. A detailed comparison with standard capacitive wave gauges is also performed. Spectral analysis of a random-forced wave field is used to obtain the dispersion relation of water waves, demonstrating the potentialities of the setup for the investigation of the statistical properties of surface waves

Hydrodynamic Supercontinuum

We demonstrate experimentally multi-bound-soliton solutions of the Nonlinear Schr\"odinger equation (NLS) in the context of surface gravity waves. In particular, the Satsuma-Yajima N-soliton solution with N=2,3,4 is investigated in detail. Such solutions, also known as breathers on zero background, lead to periodic self-focussing in the wave group dynamics, and the consequent generation of a steep localized carrier wave underneath the group envelope. Our experimental results are compared with predictions from the NLS for low steepness initial conditions where wave-breaking does not occur, with very good agreement. We also show the first detailed experimental study of irreversible massive spectral broadening of the water wave spectrum, which we refer to by analogy with optics as the first controlled observation of hydrodynamic supercontinuum a process which is shown to be associated with the fission of the initial multi-soliton bound state into individual fundamental solitons similar to what has been observe in optics

Single Wall Nanotubes: Atomic Like Behaviour and Microscopic Approach

Recent experiments about the low temperature behaviour of a Single Wall Carbon Nanotube (SWCNT) showed typical Coulomb Blockade (CB) peaks in the zero bias conductance and allowed us to investigate the energy levels of interacting electrons. Other experiments confirmed the theoretical prediction about the crucial role which the long range nature of the Coulomb interaction plays in the correlated electronic transport through a SWCNT with two intramolecular tunneling barriers. In order to investigate the effects on low dimensional electron systems due to the range of electron electron repulsion, we introduce a model for the interaction which interpolates well between short and long range regimes. Our results could be compared with experimental data obtained in SWCNTs and with those obtained for an ideal vertical Quantum Dot (QD). For a better understanding of some experimental results we also discuss how defects and doping can break some symmetries of the bandstructure of a SWCNT.Comment: 8 pages, 4 figure