A Study Of Student Use Of An Online Message Board In An Introductory Physics Class

With the rapid development of the Internet, increasingly universities and colleges transfer some of their teaching assignments online. Online learning plays an important role in assisting or sometimes substituting for the traditional face-toace learning. An online message board is one of several online communication tools which are used to assist online learning. We have conducted a study on the role of the online message board in teaching one of these courses, an introductory course in calculus-based physics. The study analyzed students? use of the message board and investigated whether use is correlated with performance in the class. Results suggest that students have benefited from using the online message board. Both homework related message board activities and non-learning message boardn activities were found to be correlated significantly to the grades the students earned in the course

Effect of a combination of omeprazole and high-dose proton pump inhibitors on the treatment of patients with liver cirrhosis complicated with upper gastrointestinal hemorrhage

Purpose: To determine the effect of a combination of omeprazole and high-dose proton pump inhibitor (PPI) on the treatment of patients with liver cirrhosis complicated with upper gastrointestinal hemorrhage.Methods: A total of 100 patients with liver cirrhosis and upper gastrointestinal hemorrhage who were admitted to Qingdao Chengyang District People’s Hospital from January 2019 to September 2020 were matched and randomly assigned to a control group and a study group. Patients in both groups received a high-dose PPI treatment, while those in the study group were given omeprazole in addition to highdose PPI. Total treatment effectiveness, incidence of adverse reactions, bleeding volume, hemostasis time, liver function after treatment, Quality of Life Index (QLI) scores, Visual Analogue Scale (VAS) scores, and bleeding (%) at 1, 2 and 4 weeks after treatment were compared for the two groups of patients.Results: Omeprazole-PPI combination produced a much more favorable outcome than treatment with only high-dose PPI, in terms of effectiveness, QLI scores and liver function (p < 0.05). The study group had significantly lower incidence of adverse reactions, bleeding volume, VAS scores, and degree of bleeding at 1, 2 and 4 weeks after treatment, as well as shorter hemostasis time, than the control group (p < 0.05).Conclusion: A combination treatment of omeprazole and high-dose PPI produces better therapeutic effect than high-dose PPI alone, in patients with liver cirrhosis and upper gastrointestinal hemorrhage

Superconducting traction transformer

An ongoing project to develop HTS traction transformers for the Chinese Fuxing high-speed train is demonstrating that the high-power density can be reached using high-temperature superconductors (HTS). The findings are spectacular: the existing 6.5 MVA traction transformers can be replaced with drop-in superconducting transformers, achieving targets of less than 3 tons transformer system weight and 99.5 % efficiency compared to 6 tons and 95 % in the existing devices. The key to achieving these impressive figures is minimizing the AC loss of the HTS windings. New high-performance wire, high current HTS Roebel conductor, high aspect-ratio windings, and flux diverters placed at the winding ends all contribute to reducing the electrical loss to less than 2 kW

Interaction of acetamiprid with extracellular polymeric substances (EPS) from activated sludge: A fluorescence study

Extracellular polymeric substances (EPS) are important components of activated sludge and it plays an important role in removing pollutants. The interaction between EPS and organic pollutants is still little known. In the present study, the interaction of soluble/bound EPS with acetamiprid, a neonicotinoid insecticide, was investigated using the three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy. The fluorescence spectra of EPS revealed that there were two classes of protein-like fluorophores in soluble/bound EPS and one class of fulvic acid-like fluorophore, in addition, in bound EPS. The quenching of protein-like fluorescence by acetamiprid indicated that static quenching (at peak B) and combined quenching (at peak A) occurred simultaneously. The interaction of acetamiprid with EPS was observed to have resulted in the formation of acetamiprid-EPS complexes. The binding constants of the soluble EPS for acetamiprid were greater than those of the bound EPS, indicating the soluble EPS had stronger binding capacity for acetamiprid than the bound EPS. This study confirmed that EPS (soluble/bound) play important roles in biosorption of organic pollutants by activated sludge and also indicated that they may serve as a protective barrier against toxic organic matter, for the microorganisms.Key words: Extracellular polymeric substance (EPS), activated sludge, fluorescence quenching, binding constant, acetamiprid

Design consideration and conductor selection of a low AC loss HTS REBCO magnet carrying high currents at 20 K and 40 K

AC loss in high temperature superconductor coils have been frequently studied, however, mostly for AC power applications at 77 K, rather than specifically for high current but low frequency AC superconducting magnet at 20–40 K. Due to their easy operation and Helium shortage, more HTS magnet systems employ conduction-cooling with cryocoolers. The HTS magnets are known for high stability and likely tolerate high AC loss, but it is unclear what is the maximum AC frequency assuming that cryocooler has limited capability (a few hundred Watts) for the 20-40 K temperature range. This paper will specifically study AC loss in a simple HTS dipole but with three conductor/cable options using simulations, (1) 12 mm wide tape, (2) two parallel 6 mm wide tapes, and (3) 6/2 (six 2 mm strands) Roebel cables. It has been found that the magnet at 5 Hz generates 200–400 W AC loss at 20 K or 40 K, potentially be cooled by two single stage cryocoolers. The 6/2 Roebel cable based magnet may allow higher frequency (6–8 Hz) due to its transposition and narrower conductor width

The Measurement of the Long-Term and Short-Term Risks of Chinese Listed Banks

In this paper, we employ Semi-APARCH model to measure and analyze the long-term and the short-term risk of Chinese 16 listed commercial banks between January 2007 and December 2013, and provide an early warning method for financial regulation by developing a scale function. We find that, first, during the financial crisis of 2008-2009, the long-term risk levels of Chinese banking industry as a whole and the individual commercial banks are very higher, they gradually declined to the normal level only after 2010. Secondly, the current risk of Chinese banks and banking industry is at lower level. Thirdly, the surging of overnight rate in 2013 increased the risk level of commercial banks, which could increase more, of which the regulator should be more cautious. Fourthly, the leverage-effects in the short-term risk of Chinese commercial banks are lower; t-distribution shows a fat-tail. Fifthly, the scale functions of commercial banks are highly correlated, the correlation coefficients are close to 1, which indicates a significantly systematically correlations between the long-term risk of Chinese commercial banks