The growth of school mathematics : Korean secondary gifted students' collaborative problem solving using the Wiki

"May 2014."Dissertation Chairman: Dr. Barbara Reys.Includes vita.Electronic networks have provided new intellectual environments where people can accumulate their cognitive power and have increased the necessity to provide students opportunity to learn together in online CoI (Community of Inquiry) beyond classroom walls. In this respect, this study, as a design experiment, investigated the applicability of the Wiki as a collaborative problem solving tool in Korean secondary gifted educational environments. Fourteen Korean secondary gifted students enrolled in a calculus II course, including two females, in a gifted school in Korea collaboratively solved ten calculus problems for 70 days. In this study, the Wiki functioned as a collective cognitive tool by coalescing individual thinking processes into collective thinking processes on the one hand and by distributing cognitive loads of problem solving over individual cognitions along the logic of solutions and refutations on the other hand. This study provides evidence that the Wiki provided Korean secondary gifted students opportunity to experience collaborative learning and growth of school mathematics and thus realized connected knowing via mathematical contents in online CoI in spite of the inconvenience of writing mathematical expressions using the Wiki.Includes bibliographical references (pages 182-195)

Function Concept: Learning from History

The importance of functions in school mathematics has grown tremendously within the past century. Functions have progressed from being scantly represented in school mathematics to being a core mathematical topic. C.B. Boyer (1946) acknowledged “The development of the function concept has revolutionized mathematics in much the same way as did the nearly simultaneous rise of non-Euclidean geometry. It has transformed mathematics from a pure natural science- the queen of the sciences- into something vastly large. It has established mathematics as the basis of all rigorous thinking – the logic of all possible relations” (Markovits, Eylor, & Bruckheimer, 1986, p. 18). Historical speeches and documents, such as Klein’s 1893 Evanston Colloquium, Moore’s 1902 presidential address to the American Mathematical Society, The Reorganization of Mathematics in Secondary Education Report (1923), and The Report of Progressive Education and Joint Committee (1940), advocated that functions and “relational thinking” be a core concept in school mathematics. In fact, Felix Klein considered functions to be the “soul of mathematics”, and advocated that teachers teach functional concepts. Fortunately, the recommendations made decades ago pertaining to the importance of functions, and the needs to readily integrate the function concept into school mathematics by researchers were not ignored. The recommendations made regarding functions decades ago are evident in today’s curriculum standards. Standards for mathematics require students to be able to define functions, describe functions, identify functions, analyze functions, and recognize patterns in function (NCTM, 2000; Common Core State Standards 2010). Most notably, The Common Core State Standards (2010) has functions as one of five conceptual categories in high school mathematics. Considering the increased emphasis placed on functions in school mathematics within the past century, we sought to describe how the function concept was presented in secondary mathematics textbooks prior to the “New Math” era

Reidemeister orbit sets

The Reidemeister orbit set plays a crucial role in the Nielsen type theory of periodic orbits, much as the Reidemeister set does in Nielsen fixed point theory. Extending Ferrario's work on Reidemeister sets, we obtain algebraic results such as addition formulae for Reidemeister orbit sets. Similar formulae for Nielsen type essential orbit numbers are also proved for fibre preserving maps.MathematicsSCI(E)0ARTICLE2139-15618

Per-Clip Video Object Segmentation

Recently, memory-based approaches show promising results on semi-supervised video object segmentation. These methods predict object masks frame-by-frame with the help of frequently updated memory of the previous mask. Different from this per-frame inference, we investigate an alternative perspective by treating video object segmentation as clip-wise mask propagation. In this per-clip inference scheme, we update the memory with an interval and simultaneously process a set of consecutive frames (i.e. clip) between the memory updates. The scheme provides two potential benefits: accuracy gain by clip-level optimization and efficiency gain by parallel computation of multiple frames. To this end, we propose a new method tailored for the per-clip inference. Specifically, we first introduce a clip-wise operation to refine the features based on intra-clip correlation. In addition, we employ a progressive matching mechanism for efficient information-passing within a clip. With the synergy of two modules and a newly proposed per-clip based training, our network achieves state-of-the-art performance on Youtube-VOS 2018/2019 val (84.6% and 84.6%) and DAVIS 2016/2017 val (91.9% and 86.1%). Furthermore, our model shows a great speed-accuracy trade-off with varying memory update intervals, which leads to huge flexibility.Comment: CVPR 2022; Code is available at https://github.com/pkyong95/PCVO

Case report: Fatal neonatal sepsis associated with Escherichia fergusonii infection in a common bottlenose dolphin (Tursiops truncatus)

A 25-day-old male common bottlenose dolphin (Tursiops truncatus) died suddenly while swimming at a dolphinarium. The gross examination revealed ulceration on the dorsal and pectoral fins and rostrum. Severe congestion, hemorrhage, and edema were observed in the gastrointestinal tract, liver, mesenteric lymph nodes, lungs, and kidneys. Fibrinosuppurative arthritis of the atlantooccipital joint and extension of fibrin into the spinal canal caused compression of the spinal cord. Histopathological examination revealed tracheitis, fibrinosuppurative bronchopneumonia and enteritis. In the central nervous system, meningeal vessel congestion in the brain, and intraparenchymal hemorrhages with neurodegeneration were observed in the spinal cord. Based on the histopathological findings, representative samples, including lung, liver, mesenteric lymph node, blood obtained from the jugular vein, and fluid sample of the ascites, were inoculated on tryptic soy agar and blood agar for routine bacterial isolation. Each isolated bacterial colony was streaked aseptically onto tryptic soy agar and blood agar for pure culture. After then, polymerase chain reaction (PCR) was performed for further identification of pathogenic microorganisms. PCR identified Escherichia fergusonii, Shewanella haliotis, Enterococcus faecalis, and Staphylococcus schleiferi. E. fergusonii was considered the primary etiologic agent in this case since it was the only species identified in all representative samples. The cause of death in this animal was E. fergusonii sepsis. To the best of our knowledge, this is the first case of neonatal sepsis associated with E. fergusonii infection in a dolphin, and suggests E. fergusonii as an opportunistic pathogen associated with sepsis in dolphins

Postcardiac Injury Syndrome after Percutaneous Coronary Intervention

The post cardiac injury syndrome is characterized by the development of a fever, pleuropericarditis, and parenchymal pulmonary infiltrates in the weeks following trauma to the pericardium or myocardium. According to previous reports, almost all cases develop after major cardiac surgery or a myocardial infarction. Recently, a few reports have described post cardiac injury syndrome as a complication of endovascular procedures such as percutaneous cardiac intervention. Here we describe an unusual case of post cardiac injury syndrome after a percutaneous coronary intervention

A Case of Malignant Pericardial Mesothelioma With Constrictive Pericarditis Physiology Misdiagnosed as Pericardial Metastatic Cancer

Malignant pericardial mesothelioma is a rare and progressive cardiac tumor. There is no established standard treatment and the prognosis is poor. Most patients were retrospectively diagnosed from surgery or autopsy due to absence of specific clinical manifestation. Most patients with pericardial mesothelioma have demonstrated constrictive physiology on echocardiography or cardiac catheterization. Therefore, pericardial mesothelioma was often misdiagnosed as other causes of constrictive pericarditis. We report a case of primary pericardial mesothelioma misdiagnosed as pericardial metastasis of unknown origin

Development of Anthropometry-Based Equations for the Estimation of the Total Body Water in Koreans

For developing race-specific anthropometry-based total body water (TBW) equations, we measured TBW using bioelectrical impedance analysis (TBWBIA) in 2,943 healthy Korean adults. Among them, 2,223 were used as a reference group. Two equations (TBWK1 and TBWK2) were developed based on age, sex, height, and body weight. The adjusted R2 was 0.908 for TBWK1 and 0.910 for TBWK2. The remaining 720 subjects were used for the validation of our results. Watson (TBWW) and Hume-Weyers (TBWH) formulas were also used. In men, TBWBIA showed the highest correlation with TBWH, followed by TBWK1, TBWK2 and TBWW. TBWK1 and TBWK2 showed the lower root mean square errors (RMSE) and mean prediction errors (ME) than TBWW and TBWH. On the Bland-Altman plot, the correlations between the differences and means were smaller for TBWK2 than for TBWK1. On the contrary, TBWBIA showed the highest correlation with TBWW, followed by TBWK2, TBWK1, and TBWH in females. RMSE was smallest in TBWW, followed by TBWK2, TBWK1 and TBWH. ME was closest to zero for TBWK2, followed by TBWK1, TBWW and TBWH. The correlation coefficients between the means and differences were highest in TBWW, and lowest in TBWK2. In conclusion, TBWK2 provides better accuracy with a smaller bias than the TBWW or TBWH in males. TBWK2 shows a similar accuracy, but with a smaller bias than TBWW in females

Complete Atrioventricular Block Secondary to Bortezomib Use in Multiple Myeloma

Bortezomib is an inhibitor of 26S proteasome, which is an effective treatment for multiple myeloma. The common adverse effects of bortezomib are asthenic conditions, gastrointestinal disturbances, and peripheral neuropathy. Here we describe a patient with dyspnea and general weakness because of complete atrioventricular block while receiving bortezomib. We immediately stopped bortezomib, and after inserting a permanent VDD pacemaker, the patients' symptoms disappeared