What Do Preschool Teachers and Parents Think about the Influence of Screen-Time Exposure on Children’s Development? Challenges and Opportunities

Children’s exposure to screens has been increasing in recent years and so has the concern about its impact on children’s development. This study aims to analyze preschool teachers’ and parents’ views on the influence of screen-time exposure on children’s development. Semi-structured interviews with preschool teachers (n = 9), as well as data from a previous quantitative study, based on an online questionnaire applied to parents of children in preschool (n = 266) were used for data collection. For this study, eminently of qualitative nature, the following dimensions were analyzed: children’s habits of exposure to screens at home, changes in children’s play habits at school, strategies/methodologies used by preschool teachers, use of technologies at school and children’s language development. The results from the study with parents show that screen-time exposure of children is between 1 h to 2 h of television per day, mostly to watch cartoons. Parents also report that most of the children use vocabulary in other languages at home. Most preschool teachers agreed that children are changing their play habits and mainly their behaviors and attitudes, influenced by screen-time exposure. They believe that language development is also changing, mentioning more language problems in children. Changes in pedagogic strategies and specialized training on educational technology are needed to get closer to children’s interests.

Effect of Process Parameters on the Surface Microgeometry of a Ti6Al4V Alloy Manufactured by Laser Powder Bed Fusion: 3D vs. 2D Characterization

The influence of the main process parameters, laser power, point distance and time exposure, on the surface microgeometry of Ti6Al4V specimens produced by a pulsed powder bed fusion process was investigated. A 3D characterization was carried out and collected data were elaborated to reconstruct the surface and to determine both the 3D and the 2D material ratio curves along different directions. The 3D material ratio curve gives a slightly lower material ratio of peak zone Mr1 and higher material ratio of valley zone Mr2, reduced peak height Rpk and reduced valley height Rvk than the 2D curves. Roughness is greater in the 3D analysis than in the 2D one, skewness is the same and kurtosis increases from <3 in 2D to >3 in 3D. Roughness and skewness increase on increasing point distance and decreasing time exposure and laser power. Within the investigated ranges (27.3–71.2 J/mm3), an increase in energy density reduces the surface roughness while skewness and kurtosis are not significantly affected. The results indicate that a 3D approach allows better characterization of the surface microgeometry than a 2D one.

Effect of Short Time Exposure of Local ELF-MFs on Sleepiness Induced in Male Rats

Introduction: Lack of high-quality sleep causes serious side effects like anxiety and changes in plasma concentration of oxalate. The current study aimed to investigate the impact of local extremely low frequency magnetic fields (ELF-MFs) on inducing sleep (sleepiness) and anxiety in male rats. Methods: In this experimental study, 40 male rats were allocated in four groups (n=10). The ELF-MFs exposure (0, 10 and 18 Hz) was applied with intensity 200µT for three days (10 min/day). Sham-treated animal did not receive ELF-MF. Serum level of oxalic acid (OA) and sleepiness were measured both before first and after last exposure to ELF-MF or sham. Anxiety, sleepiness and OA were measured by using elevated plus maze, open-field test (OFT) and ELISA test, respectively. Results: Comparison of oxalate levels between before and after exposure to ELF-MF revealed that ELF-MF (10 Hz) decreased the serum level of oxalate (p<0.05). Comparison of the percent of open:closed arm entry (in elevated plus maze) between before and after exposure to ELF-MF revealed significant differences. Also, frequency, velocity and distance moved were decreased in the open-field test. Conclusion: Results of the present study demonstrated that ELF-MF with short time exposure may modulate the metabolism of OA and may modulate anxiety-like behavior or kind of induction of sleepiness in male rats.

Screen time and early childhood development in Ceará, Brazil: a population-based study

Background Globally, children’s exposure to digital screens continues to increase and is associated with adverse effects on child health. We aimed to evaluate the association of screen exposure with child communication, gross-motor, fine-motor, problem-solving, and personal-social development scores. Methods We conducted a population-based, cross-sectional study with cluster sampling among children 0–60 months of age living in the state of Ceará, Brazil. Child screen time was assessed by maternal report and the World Health Organization (WHO) recommendations were used to define excessive screen time exposure. Child development was assessed with the Brazilian Ages and Stages Questionnaire. Generalized linear regression was used to determine the association of screen exposure with developmental outcomes. We also examined the potential non-linear relationship of screen time with development scores using spline analyses. Results A total of 3155 children 0–60 months of age had screen time exposure evaluated and 69% percent were identified as exposed to excessive screen time. This percentage of excess screen time increased with child age from 41.7% for children 0–12 months to 85.2% for children 49–60 months. Each additional hour of screen time was associated with lower child communication (standardized mean difference (SMD): -0.03; 95% CI: − 0.04, − 0.02), problem solving (SMD: -0.03; 95% CI: − 0.05, − 0.02) and personal-social (SMD: -0.04; 95% CI: − 0.06, − 0.03) domain scores. Conclusions Excess screen time exposure was highly prevalent and independently associated with poorer development outcomes among children under 5 years of age in Ceará, Brazil.

Characterization of Thermal and Time Exposure to Improve Artificial Diet for Western Corn Rootworm Larvae

The western corn rootworm (WCR), Diabrotica virgifera LeConte, is the most serious pest of maize in the United States. In pursuit of developing a diet free of antibiotics for WCR, we characterized effects of thermal exposure (50–141 °C) and length of exposure on quality of WCRMO-2 diet measured by life history parameters of larvae (weight, molting, and survival) reared on WCRMO-2 diet. Our results indicated that temperatures had non-linear effects on performance of WCRMO-2 diet, and no impacts were observed on the length of time exposure. The optimum temperature of diet processing was 60 °C for a duration less than 30 min. A significant decline in development was observed in larvae reared on WCRMO-2 diet pretreated above 75 °C. Exposing WCRMO-2 diet to high temperatures (110–141 °C) even if constrained for brief duration (0.9–2.3 s) caused 2-fold reduction in larval weight and significant delays in larval molting but no difference in survival for 10 days compared with the control diet prepared at 65 °C for 10 min. These findings provide insights into the effects of thermal exposure in insect diet processing.