Math Stories in Elementary Mathematics Education in China and North America

In our information- and technology-based society, mathematics education plays an increasingly important role in current world economic development. As the world biggest economies,ChinaandNorth Americahave accelerated the reform of mathematics education in recent years. One of the phenomena is that children’s literature has attracted great attention in the improvement of mathematics instruction and students’ learning for early childhood education. However, research conducted on math literature and the comparison of math literature inChinaand North America is limited, which points the necessity to consider the similarities and differences of math literature inChinaandNorth America. By comparing and contrasting the math stories in China and North America, this study presents the similarities and differences of math stories. After analyzing the findings with attention to underlying differences between stories, it appears that features of the math education system are also reflected in the differences between math stories in China and North America. As well, Chinese math stories are less developed than that inNorth America. To illustrate the differences, this study also puts forward criteria of good math stories and illustrates how to rewrite a Chinese math story to better meet these criteria. In the light of the findings, implications and recommendations for the development of math stories are provided

THE IMPACT OF OIL PRICE ON BANK PROFITABILITY IN CANADA

Using the ordinary least squares estimation, this paper analyzes the impact of oil price on bank profitability in Canada. We use data on 10 public banks from 1995 to 2015. Our profitability determinants include bank-specific characteristics and macroeconomic factors. We separately consider how banks react to two dramatically drops during these 20 years.   We find that there is a significantly positive relationship between the oil price and bank profitability in the early period, but no evidence shows that they have relationship in recent years. This evidence that Canadian banks have taken action to immunize from the risk of oil price drop

Classification of Online Customer Reviews for Digital Product Innovation: A Motivation Perspective

With rapid technological advances, digital products are becoming increasingly prevalent. Although past studies have examined the contribution of online reviews extensively in the context of physical products, there is limited understanding of the contribution of online reviews in digital product innovation. To this end, this study reviews previous work related to online reviews of physical and digital products in an attempt to reclassify online reviews of digital products from the perspective of consumer motivation. Taking game-related app reviews as an example, we employed a topic modeling model to extract insights related to consumer motivation. An in depth appreciation of consumers’ motivation from analyzing online reviews can yield invaluable insights in driving digital product innovation

Evaluation of Anti-tumor and Chemoresistance-lowering Effects of Pectolinarigenin from Cirsium japonicum Fisch ex DC in Breast Cancer

Purpose: To investigate the antitumor and chemoresistance-lowering effects of pectolinarigenin on breast cancer cells.Methods: Pectolinarigenin was purified by a combination of silica gel and Sephadex LH-20 column chromatography from ethanol extracts of the aerial parts of C. japonicum DC. Breast cancer selfrenewal properties were tested by colony formation and tumor sphere formation assays. Thereafter, real-time polymerase chain reaction (PCR) was used to detect breast cancer stem cell markers. Furthermore, the effect of pectolinarigenin on breast cancer cell was evaluated by chemoresistance using 3-(4,5-dimethyl-2 thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Finally, tumor formation in nude mice was used to test the effect of pectolinarigenin on tumorigenicity of breast cancer cells in vivo.Results: The results showed that pectolinarigenin, extracted from Cirsium japonicum Fisch. ex DC., inhibited tumor cell self-renewal in MCF-7 breast cancer cells. Pectolinarigenin (25 μM) caused significant inhibition of colony formation (61.23 %, p < 0.001) and tumor sphere formation (59.49 %, p < 0.01) in MCF-7. The inhibitory effects were associated with changes in breast cancer stem cell markers. Treatment of breast cancer cells with pectolinarigenin reduced the chemoresistance of the cells to doxorubicin. At the same time, mRNA expression of chemoresistance genes (ATP binding cassette subfamily G member 2, ABCG2 and ATP binding cassette subfamily B member 1, MDR1) was repressed by pectolinarigenin. The inhibition efficiency of MDR1 and ABCG2 by 10 μM pectolinarigenin treatment was about 59.29 (p < 0.01) and 46.48 % (p < 0.01), respectively. Furthermore, pectolinarigenin reduced tumor mass in nude mice xenograft model.Conclusion: Pectolinarigenin inhibits breast cancer stem cell-like properties and lowers the chemoresistance of the cancer cells to chemotherapy. The results provide an insight into the mechanism of the anti-breast tumor effects and an experimental basis for the use of pectolinarigenin to enhance treatment of patients with breast cancer.Keywords: Pectolinarigenin, Cancer stem cells, Breast cancer, Chemoresistance, Cirsium japonicum Fisch. ex D

Two new genera of Apsilocephalidae from mid-Cretaceous Burmese amber

Apsilocephalidae is an enigmatic dipteran family erected by Nagatomi et al. (1991), including three extant genera and three additional extinct genera from the Eocene Baltic amber, Eocene Florissant, and mid-Cretaceous Burmese amber. We describe herein two new taxa, Myanmarpsilocephala grimaldii gen. et sp. nov. and Irwinimyia spinosa gen. et sp. nov., from mid-Cretaceous Burmese amber. The female genitalia of Myanmarpsilocephala gen. nov. and male genitalia of Irwinimyia gen. nov. are described and illustrated. The distribution of all Apsilocephalidae species and a key to all genera of Apsilocephalidae is provided. The described diversity of Apsilocephalidae in Burmese amber strongly suggests that apsilocephalid flies diversified at least by the mid-Cretaceous.This research was supported by the National Natural Science Foundation of China (41572010, 41622201, 41688103), the Chinese Academy of Sciences (XDPB05), and Youth Innovation Promotion Association of CAS (No. 2011224)

What Went Wrong? Closing the Sim-to-Real Gap via Differentiable Causal Discovery

Training control policies in simulation is more appealing than on real robots directly, as it allows for exploring diverse states in a safe and efficient manner. Yet, robot simulators inevitably exhibit disparities from the real world, yielding inaccuracies that manifest as the simulation-to-real gap. Existing literature has proposed to close this gap by actively modifying specific simulator parameters to align the simulated data with real-world observations. However, the set of tunable parameters is usually manually selected to reduce the search space in a case-by-case manner, which is hard to scale up for complex systems and requires extensive domain knowledge. To address the scalability issue and automate the parameter-tuning process, we introduce an approach that aligns the simulator with the real world by discovering the causal relationship between the environment parameters and the sim-to-real gap. Concretely, our method learns a differentiable mapping from the environment parameters to the differences between simulated and real-world robot-object trajectories. This mapping is governed by a simultaneously-learned causal graph to help prune the search space of parameters, provide better interpretability, and improve generalization. We perform experiments to achieve both sim-to-sim and sim-to-real transfer, and show that our method has significant improvements in trajectory alignment and task success rate over strong baselines in a challenging manipulation task

Development of Near-Isogenic Lines in a Parthenogenetically Reproduced Thrips Species, \u3cem\u3eFrankliniella occidentalis\u3c/em\u3e

Although near-isogenic lines (NILs) can standardize genetic backgrounds among individuals, it has never been applied in parthenogenetically reproduced animals. Here, through multiple rounds of backcrossing and spinosad screening, we generated spinosad resistant NILs in the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), with a haplo-diploid reproduction system. The resultant F. occidentalis NIL-R strain maintained a resistance ratio over 30,000-fold, which was comparable to its parental resistant strain, Spin-R. More importantly, F. occidentalis NIL-R shared 98.90% genetic similarity with its susceptible parental strain Ivf03. By developing this toolset, we are able to segregate individual resistance and facilitate the mechanistic study of insecticide resistances in phloem-feeding arthropods, a group of devastating pest species reproducing sexually as well as asexually

Development of Near-Isogenic Lines in a Parthenogenetically Reproduced Thrips Species, \u3cem\u3eFrankliniella occidentalis\u3c/em\u3e

Although near-isogenic lines (NILs) can standardize genetic backgrounds among individuals, it has never been applied in parthenogenetically reproduced animals. Here, through multiple rounds of backcrossing and spinosad screening, we generated spinosad resistant NILs in the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), with a haplo-diploid reproduction system. The resultant F. occidentalis NIL-R strain maintained a resistance ratio over 30,000-fold, which was comparable to its parental resistant strain, Spin-R. More importantly, F. occidentalis NIL-R shared 98.90% genetic similarity with its susceptible parental strain Ivf03. By developing this toolset, we are able to segregate individual resistance and facilitate the mechanistic study of insecticide resistances in phloem-feeding arthropods, a group of devastating pest species reproducing sexually as well as asexually

Partially bonded aluminum site on the external surface of post-treated Au/ZSM-5 enhances methane oxidation to oxygenates

Au nanoparticles supported on the exterior surface of the ZSM-5 zeolite (Au/ZSM-5) have shown the ability to partially oxidize methane to methanol and acetic acid. However, further improvements to the catalyst activity are required. This study investigates the effect of modifying the acidic properties of the ZSM-5 support through a desilication–recrystallization (DR) process on the activity of Au/ZSM-5 catalysts toward methane oxidation. A DR treatment of 24 h leads to a 50% higher oxygenate yield compared to the analogous catalyst prepared using the untreated support. Characterization using solid-state 27Al NMR and FTIR adsorption of pyridine and 2,4,6-trimethylpyridine reveals that DR induces framework dealumination and redistribution of Brønsted acid sites to the zeolite external surface. Two-dimensional 27Al MQMAS NMR further identifies partially coordinated framework Al sites on the zeolite surface, correlating with a higher oxygenate yield. These external acid sites help stabilize the Au nanoparticles, enhancing catalyst stability for methane partial oxidation