Effectiveness of ST Math in College Remedial Mathematics Students of Learning Fraction Concepts

This study examined the extent to which the iPad app, Spatial Temporal Mathematics (ST Math), diminished college remedial mathematics students’ natural number bias and deepened their fraction conceptual understanding. In this quasi-experimental study one class played the ST Math fraction games for 8 weeks, and they were compared to a control class who were taught without technology. The frameworks for this study included the framework theory of conceptual change, the reorganization theory, the microworld and the Lesh Translation Model. Pre and post- tests were used to examine the fraction conceptual understanding of the students in the ST Math class and the non-ST Math class before and after the intervention. Also, interviews were conducted to investigate how the ST Math students developed their fraction conceptual understand before and after the game play, compared to the non-ST Math students. As a whole, the students in both classes exhibited the natural number bias in all three areas: magnitude, density, and computation at the pre-test stage. However at the post-test stage, they diminished the bias in magnitude but in the other two areas, the bias was persistent. Overall, the statistical result was not significant between the ST Math class and the non-ST Math class on the post-test. However, the ST Math class had more students who answered correctly regarding the fraction density concept on the post-test. Similarly, the post-interview results revealed that the ST Math students exhibited conceptual gain in fraction magnitude, the fraction addition concept, and the fraction multiplication concept. However, although they showed the conceptual gain in fraction multiplication, they had difficulty with the concept of fraction division. The students in both classes did not show any conceptual gain in fraction division

On the Diffusion of Silver into Glass

The diffusion of silver into glass was measured by means of a tracer technique, with radioactive Ag-110, over the temperature range from 500 to 600℃ below the softening point. From the observed data, the diffusion equation can be represented by D=1.91×10^exp(-27000/RT)cm^2 sec^

Rider Assist Technologies: Popular Types, Motivations for Use, and Information Sources Consulted by Users

The ubiquity of advanced in-vehicle technologies for cars highlights the relative scarcity of comparable offerings for motorcycles despite the fact that many can be adapted for this mode of transportation. Aspects of Intelligent Transport Systems (ITS) such as advanced rider assist technologies may increase the safety of motorcyclists. In this study, we surveyed motorcycle riders about the types of advance technologies their current bikes were equipped with, as well as, the primary motivation for purchasing the technology, and how they learned to use the technologies (if applicable). The most frequently reported technologies owned by riders were handle bar controls, engine brake controls, and cruise control. The primary motivation reported for using the technology was increased safety and improved riding capabilities. The riders were more likely to consult online resources (e.g., YouTube) instead of the manufacturer’s materials when learning about the advanced features of their bikes. While the accessibility of the information makes it easy to reference, the lack of standardization and validity of the online content could contribute to the potential misuse of the technology

Oxidative damage and brain concentrations of free amino acid in chicks exposed to high ambient temperature

High ambient temperatures (HT) reduce food intake and body weight in young chickens, and HT can cause increased expression of hypothalamic neuropeptides. The mechanisms by which HT act, and the effects of HT on cellular homeostasis in the brain, are however not well understood. In the current study lipid peroxidation and amino acid metabolism were measured in the brains of 14 d old chicks exposed to HT (35 °C for 24- or 48-h) or to control thermoneutral temperature (CT; 30 °C). Malondialdehyde (MDA) was measured in the brain to determine the degree of oxidative damage. HT increased body temperature and reduced food intake and body weight gain. HT also increased diencephalic oxidative damage after 48 h, and altered some free amino acid concentrations in the diencephalon. Diencephalic MDA concentrations were increased by HT and time, with the effect of HT more prominent with increasing time. HT altered cystathionine, serine, tyrosine and isoleucine concentrations. Cystathionine was lower in HT birds compared with CT birds at 24 h, whilst serine, tyrosine and isoleucine were higher at 48 h in HT birds. An increase in oxidative damage and alterations in amino acid concentrations in the diencephalon may contribute to the physiological, behavioral and thermoregulatory responses of heat-exposed chicks

Cnm of Streptococcus mutans is important for cell surface structure and membrane permeability

Streptococcus mutans, a Gram-positive facultative anaerobic bacterium, is a major pathogen of dental caries. The protein Cnm of S. mutans is involved in collagen binding, but its other biological functions are unknown. In this study, a Cnm-deficient isogenic mutant and a complementation strain were generated from a Cnm-positive S. mutans strain to help determine the properties of Cnm. Initially, comparison of the cell surface structure was performed by electron microscopy, which demonstrated that Cnm appears to be localized on the cell surface and associated with a protruding cell surface structure. Deep RNA sequencing of the strains revealed that the defect in Cnm caused upregulated expression of many genes related to ABC transporters and cell-surface proteins, while a few genes were downregulated. The amount of biofilm formed by the Cnm-defective strain increased compared with the parental and complemented strains, but the biofilm structure was thinner because of elevated expression of genes encoding glucan synthesis enzymes, leading to increased production of extracellular polysaccharides. Particular antibiotics, including bacitracin and chloramphenicol, had a lower minimum inhibitory concentration for the Cnm-defective strain than particular antibiotics, including bacitracin and chloramphenicol, compared with the parental and complemented strains. Our results suggest that S. mutans Cnm is located on the cell surface, gives rise to the observed protruding cell surface, and is associated with several biological properties related to membrane permeability