Parental perspectives on children’s use of portable digital devices

<p>Small portable digital devices (PDDs) – tablets and smartphones – are becoming increasingly popular among children at early ages. In this qualitative study, we applied the theoretical frameworks of <i>self-efficacy</i> and <i>othermothering</i> to examine the perspectives of parents from rural areas regarding the role of PDDs in children of early and primary education age (4–7 years old). We conducted in-depth interviews with parents, observed children at home, and collected artefacts related to children’s PDDs use to capture daily habits, experiences, and attitudes from different angles. Data revealed that parents supported PDDs as entertainment and learning tools. Parents reported improvements in dexterity, memory, attention, and linguistic and mathematical skills, and believed that PDDs positively affect children’s cognitive development. During observations, children exhibited versatility and skill with app navigation for entertainment and educational purposes. Children completed tasks in an independent and efficacious manner that reinforced engagement. Parents seemed to unconsciously transfer to PDDs a cognitive and social role that created another parenting modality as in othermothering. Parents, meanwhile, appeared concerned with uncontrolled overuse of PDDs by children. These findings suggest that parents from rural areas view PDDs as tools that pose opportunities and challenges for entertainment and learning.</p

Relationship between ACS groups and the fractures.

<p>ACS  =  aortic calcifications score.</p><p>*p<0.01 vs G1.</p

Tetraphenylphosphonium Bromide as a Cathode Buffer Layer Material for Highly Efficient Polymer Solar Cells

Here, we introduced the role of small organic molecule tetraphenylphosphonium bromide (<b>QPhPBr</b>) as an electron-transporting layer (ETL) material for fabricating high-efficiency bulk heterojunction polymer solar cells (PSCs). Their significantly higher power conversion efficiency (PCE) in well-known active layer devices (PTB7-Th:PC₇₁BM, PBDTTT-CT:PC₇₁BM, and P3HT:PC₇₁BM) was observed compared to that of the bare Al cathode. The use of N719 as an ETL was also demonstrated. Observed data reveal that <b>QPhPBr</b>-based devices exhibit high PCEs up to 9.18, 8.42, and 4.81% from PTB7-Th, PBDTTT-CT, and P3HT, respectively. For comparisons, the bare Al devices show PCEs of 5.37, 4.75, and 3.01%, respectively. Moreover, further enhancement of PSC efficiency (9.83, 8.69, and 5.35%) is achieved from mixed binary solution of <b>N719:QPhPBr</b> because of modulated adjustment of the work function of the Al electrode. Our results indicate the excellent function of tetraphenylphosphonium bromide and its binary blend as effective small-molecule organic materials to regulate the metal surface properties and the potential used as excellent cathode buffer layer materials for realizing high-efficiency PSCs

Incidence of vertebral and non-vertebral fractures per 100 person-years by age and site.

<p>Incidence of vertebral and non-vertebral fractures was significantly higher in the 60- to 69-year-old group, the 70- to 79-year-old group and the>80-year-old group compared to the 50- to 59-year-old group (p<0.001, respectively). In each group, the vertebral fracture prevalence was significantly higher than for non-vertebral fractures (p<0.001).</p

Investigation on Thermal Degradation of Poly(1,4-butylene terephthalate) Filled with Aluminum Hypophosphite and Trimer by Thermogravimetric Analysis–Fourier Transform Infrared Spectroscopy and Thermogravimetric Analysis–Mass Spectrometry

Flame-retarded poly­(1,4-butylene terephthalate) (PBT) has been prepared using aluminum hypophosphite (AHP) and tri­(1-oxo-2,6,7-trioxa-1-phosphabicyclo­[2,2,2]­octane-methyl)­phosphate (Trimer). The combustion properties of flame-retarded PBT were evaluated using limiting oxygen index, UL-94, and cone calorimetry. The cone calorimeter data indicated that the presence of PBT/AHP/Trimer imparted a significant smoke-suppressing effect. The thermal degradation properties of flame-retarded PBT were investigated using thermogravimetric analysis–Fourier transform infrared and thermogravimetric analysis–mass spectrometry. For the samples of PBT, PBT/25% AHP, and PBT/AHP/Trimer, the main gas pyrolysis products were CO₂ and butadiene; the sample of PBT/AHP/Trimer generated less CO₂ and butadiene and consequently retained more carbon in the matrix. The amount of phosphorus–oxygen radicals of PBT/25% AHP was 1.3 times that of PBT/AHP/Trimer, which indicated that AHP alone showed slightly stronger gaseous phase effect than the combination of AHP and Trimer. This result is further confirmed by the analysis of the char residues by X-ray photoelectron spectroscopy

Rechargeable Aqueous Zn–V₂O₅ Battery with High Energy Density and Long Cycle Life

We report an aqueous Zn–V₂O₅ battery chemistry employing commercial V₂O₅ cathode, Zn anode, and 3 M Zn­(CF₃SO₃)₂ electrolyte. We elucidate the Zn-storage mechanism in the V₂O₅ cathode to be that hydrated Zn²⁺ can reversibly (de)­intercalate through the layered structure. The function of the co-intercalated H₂O is revealed to be shielding the electrostatic interactions between Zn²⁺ and the host framework, accounting for the enhanced kinetics. In addition, the pristine bulk V₂O₅ gradually evolves into porous nanosheets upon cycling, providing more active sites for Zn²⁺ storage and thus rendering an initial capacity increase. As a consequence, a reversible capacity of 470 mAh g^–1 at 0.2 A g^–1 and a long-term cyclability with 91.1% capacity rentention over 4000 cycles at 5 A g^–1 are achieved. The combination of the good battery performance, safety, scalable materials synthesis, and facile cell assembly indicates this aqueous Zn–V₂O₅ system is promising for stationary grid storage applications

Mercury Distribution and Deposition in Glacier Snow over Western China

Western China is home to the largest aggregate of glaciers outside the polar regions, yet little is known about how the glaciers in this area affect the transport and cycling of mercury (Hg) regionally and globally. From 2005 to 2010, extensive glacier snow sampling campaigns were carried out in 14 snowpits from 9 glaciers over western China, and the vertical distribution profiles of Hg were obtained. The Total Hg (THg) concentrations in the glacier snow ranged from <1 to 43.6 ng L^–1, and exhibited clear seasonal variations with lower values in summer than in winter. Spatially, higher THg concentrations were typically observed in glacier snows from the northern region where atmospheric particulate loading is comparably high. Glacier snowpit Hg was largely dependent on particulate matters and was associated with particulate Hg, which is less prone to postdepositional changes, thus providing a valuable record of atmospheric Hg deposition. Estimated atmospheric Hg depositional fluxes ranged from 0.74 to 7.89 μg m^–2 yr^–1, agreeing very well with the global natural values, but are one to two orders of magnitude lower than that of the neighboring East Asia. Elevated Hg concentrations were observed in refrozen ice layers in several snowpits subjected to intense melt, indicating that Hg can be potentially released to meltwater