The Mediating Effects of Problematic Internet and Video Gaming Behaviors on Family, Cultural, and Individual Constructs among Latinx and non-Latinx Black Youth

Problematic Internet use (PIU) and problematic video gaming (PVG) are associated with various negative health outcomes and are increasingly concerning behavioral health issues among youth. While market research indicates that US Latinx use the Internet and video games more frequently than non-Latinx US youth, research on PIU and PVG among this historically understudied population is lacking. Accordingly, data on PIU, PVG, parental monitoring, sleep quality, substance use, anxiety, depression, parental attachment, acculturation, and positive future orientation were collected using validated standardized measures from three separate samples of US Latinx and non-Latinx youth. The aims of this research were to explore the associations between PIU, PVG, and family, cultural, and individual wellbeing outcomes in a community sample of US Latinx and non-Latinx black adolescents. The first study (N = 159) examined the incidence of PVG among youth and found that younger elementary school aged males (ages 6-11) had the highest PVG scores, followed by middle school aged males (ages 12-14), and high school aged males (ages 15-18). Building off previous research, the second study collected data (N = 247) examined PIU as a mediator of the association between parental monitoring and academic achievement, sleep quality, substance use, anxiety, and depression. Structural equation modelling (SEM) was used to estimate the relationships between the variables, controlling for adolescent’s age, sex, and race/ethnicity. Results revealed that PIU is a significant mediator between parental monitoring and low academic achievement, sleep quality, substance use, anxiety, and depression. A third study was conducted to examine if PIU and PVG mediate the relation between family, cultural, individual constructs and academic achievement. Two separate simple mediation models were tested using PROCESS© macro v3.0 for SPSS 25. Results from the hypothesized mediation models were not significant. Suggestions for future research to examine critical Latinx cultural values and their influence on behavioral health is discussed

Micropropagación de Ulmus minor y U. minor x U. pumila a partir de ramets de 4 años de edad

As part of the Spanish breeding programme against Dutch elm disease, investigations were undertaken on reproduction of Ulmus minor by means of tissue culture. Microshoots were obtained from nodal segments, collected from terminal twigs of 4-year-old ramets of selected clones of this species and of U. minor x U. pumila, and cultured on a modified Murashige & Skoog medium containing 6-Benzylaminopurine (BA). When subcultured, the microshoots or nodal segments excised from these, formed new shoots, their maximum numbers per explant (1.94 to 2) being obtained with the hybrid clone M-TC2 on media containing 3.5 to 8.8 μM BA. The number of microshoots obtained was highest with subcultures of the whole shoot, e.g. 6.9 times superior to control, against 1.5 with nodal segments of VJR1 in presence of 8.8 μM BA. The addition of 0.5 to 5.3 μM indole-acetic acid of α-naphthaleneacetic acid to the medium induced the highest percentage of root formation from the shoots. Both shoot and root formation varied greatly among clones.En el presente trabajo se describen los trabajos sobre reproducción de Ulmus minor mediante las técnicas de cultivo de tejidos, llevados a cabo en el marco del Programa de Mejora Genética Español de los Olmos Frente a la Grafiosis. Brotes obtenidos a partir de segmentos nodales de ramillos terminales de ramets de 4 años de edad, pertenecientes a clones seleccionados de esta especie y de U. minor x U. pumila, fueron cultivados en el medio de Murashige & Skoog modificado conteniendo 6-Bencilaminopurina (BA). Una vez subcultivados los brotes enteros o los segmentos nodales obtenidos a partir del material vegetal in vitro, se originaron nuevos brotes, y fue el clon híbrido MTC2 el que proporcionó un mayor número por explanto (1,94 a 2) sobre medio conteniendo 3,5 a 8,8 μM BA. El número de brotes obtenidos fue mayor cuando todo el brote fue subcultivado, e.g. 6,9 veces superior al control, frente a 1,5 con segmentos nodales de V-JR1 en presencia de 8,8 μM BA. La adición de 0,5 a 5,3 mm de ácido indolacético o α-naftalenacético al medio, provocó el mayor porcentaje de formación de raíz en los brotes. Tanto la formación de brotes como la formación de raíz fue muy variable entre clones

Experimental evidence of delocalized states in random dimer superlattices

We study the electronic properties of GaAs-AlGaAs superlattices with intentional correlated disorder by means of photoluminescence and vertical dc resistance. The results are compared to those obtained in ordered and uncorrelated disordered superlattices. We report the first experimental evidence that spatial correlations inhibit localization of states in disordered low-dimensional systems, as our previous theoretical calculations suggested, in contrast to the earlier belief that all eigenstates are localized.Comment: 4 pages, 5 figures. Physical Review Letters (in press

Taming Brønsted acid reactivity: nucleophilic substitutions of propargylic alcohols with n-nucleophiles mediated by phosphorus-based Brønsted acid catalysts

The activity of diethyl phosphite and diphenyl phosphate in propargylation reactions with N-nucleophiles of varying basicity is presented. Careful choice of the reaction conditions minimised undesired rearrangements and arylation processes, typical side reactions with Brønsted acid catalysis. These systems are compatible with technical solvents and presence of air and they are also applicable to C-, O- and S-nucleophile

Circularly Polarized Resonant Rayleigh Scattering and Skyrmions in the ν\nu = 1 Quantum Hall Ferromagnet

We use the circularly polarized resonant Rayleigh scattering (RRS) to study the quantum Hall ferromagnet at $\nu$ = 1. At this filling factor we observe a right handed copolarized RRS which probes the Skyrmion spin texture of the electrons in the photoexcited grounds state. The resonant scattering is not present in the left handed copolarization, and this can be related to the correlation between Skymionic effects, screening and spin wave excitations. These results evidence that RRS is a valid method for the study of the spin texture of the quantum Hall states

Aggregation equations with fractional diffusion : preventing concentration by mixing

We investigate a class of aggregation-diffusion equations with strongly singular kernels and weak (fractional) dissipation in the presence of an incompressible flow. Without the flow the equations are supercritical in the sense that the tendency to concentrate dominates the strength of diffusion and solutions emanating from sufficiently localised initial data may explode in finite time. The main purpose of this paper is to show that under suitable spectral conditions on the flow, which guarantee good mixing properties, for any regular initial datum the solution to the corresponding advection-aggregation-diffusion equation is global if the prescribed flow is sufficiently fast. This paper can be seen as a partial extension of [Kiselev & Xu, Arch. Rat. Mech. Anal., 222(2):1077-1112, 2016], and our arguments show in particular that the suppression mechanism for the classical 2D parabolic-elliptic Keller–Segel model devised by Kiselev and Xu also applies to the fractional Keller–Segel model (where Δ is replaced by −(−Δ)γ2) requiring only that γ>1. In addition, we remove the restriction to dimension d<4. As a by-product, a characterisation of the class of relaxation enhancing flows on the d-torus is extended to the case of fractional dissipation

DNA/Histone Ratio in Different Regions of Polytene Chromosomes in the Embryo Suspensor Cells of Phaseolus Coccineus

SUMMARYThe DNA/histone ratio was calculated through Feulgen/fast green absorption in different regions of polytene chromosomes in Phaseolus coccineus embryo suspensor cells. A great variability of ratios, related with the structural characteristics of DNA in the different regions, has been found. This seems to indicate that complexes of histone with DNA may depend on changes in DNA metabolic activity. In one and the same cell, and even in one and the same chromosome, different chromosome segments have different DNA/histone ratios.These findings are discussed in relation to some characteristics of polytene chromosomes in Phaseolus suspensor cells

Electric-field control of domain wall nucleation and pinning in a metallic ferromagnet

The electric (E) field control of magnetic properties opens the prospects of an alternative to magnetic field or electric current activation to control magnetization. Multilayers with perpendicular magnetic anisotropy (PMA) have proven to be particularly sensitive to the influence of an E-field due to the interfacial origin of their anisotropy. In these systems, E-field effects have been recently applied to assist magnetization switching and control domain wall (DW) velocity. Here we report on two new applications of the E-field in a similar material : controlling DW nucleation and stopping DW propagation at the edge of the electrode