1,745 research outputs found
Revealing Online Learning Behaviors and Activity Patterns and Making Predictions with Data Mining Techniques in Online Teaching
This study was conducted with data mining (DM) techniques to analyze various patterns of online learning behaviors, and to make predictions on learning outcomes. Statistical models and machine learning DM techniques were conducted to analyze 17,934 server logs to investigate 98 undergraduate studentsâ learning behaviors in an online business course in Taiwan. The study scientifically identified studentsâ behavioral patterns and preferences in the online learning processes, differentiated active and passive learners, and found important parameters for performance prediction. The results also demonstrated how data mining techniques might be utilized to help improve online teaching and learning with suggestions for online instructors, instructional designers and courseware developers
Online Collaborative Learning in a Project-Based Learning Environment in Taiwan: A Case Study on Undergraduate Studentsâ Perspectives
This case study investigated undergraduate studentsâ first experience in online collaborative learning in a project-based learning (PBL) environment in Taiwan. Data were collected through interviews of 48 students, instructorâs field notes, researchers\u27 online observations, studentsâ online discourse and group artifacts. The findings revealed interesting phenomena as results of cultural influences as well as educational system impacts. Students experienced first handed various learning benefits of PBL in the intensive six-week period, yet voiced serious concerns about the changed role of the instructor, as well as strong reservations on peer collaboration as a result of the competitive tradition in education. Obviously, online collaborative learning and PBL critically challenged some culturally-rooted traditions in Taiwan. The study generates practical insights into the applications of online collaborative learning and PBL in Taiwan\u27s higher education as well as implications for cross-cultural implementation of online learning
The effects of progressive heart failure on the Na/K ATPase and intracellular calcium regulation
The aim of this thesis is to investigate the effects of progressive heart failure on the function of the Na/K ATPase and intracellular calcium regulation. Progressive heart failure was induced in male guinea pigs by constriction of the ascending aorta. Sham operations were carried out on the control group. Hearts were harvested and used for various experiments at 30, 60, and 150 days after the aortic constriction operation. Echocardiography was performed on unanaesthetized guinea pigs to monitor in vivo changes of contractile function. Significantly smaller fractional shortening was noted after aortic constriction although this remained stable during the progression of disease until the 150 day end point when fractional shortening decreased greatly and circulatory insufficiency presented. Heart weight : body weight ratio increased 60 days after the operation, but the lung weight : body weight ratio only increased at the 150 day end point. Electrophysiological measurements of action potential duration (APD), Ca transients, SR Ca content, and Na/K ATPase current were performed to investigate alterations of Ca regulation during the progression of heart failure using enzymatically isolated ventricular cardiac myocytes. In end-stage heart failure, APD remained prolonged and the function of other mechanisms all declined. These results supported the view that compensated hypertrophy developed at 60 days after aortic constriction, and decompensation with end stage heart failure occurred about 150 days after the operation.
At the compensated hypertrophy stage, only Na/K ATPase pump function declined but other mechanisms were enhanced or were the same as the situation prior to the constriction. These results suggested that alteration of Na/K ATPase function might assist the compensation phase and may trigger the decompensatory progression. Since t-tubule remodelling was also observed early in the heart failure progression in other study, we used membrane staining with wheat germ agglutinin (WGA) to investigate the change of t-tubule density and regularity in guinea pigs with heart failure. Our results showed a decrease in density and disorganization with regular but narrower intervals of t-tubule arrangement. Immunocytochemical staining of the α1 and α2 isoforms of the Na/K ATPase was further carried out to study their distribution in the sarcolemma when the heart fails. The results showed decreased expression of both α1 and α2 isoforms, which is compatible with our functional findings of Na/K ATPase pump current decline. Furthermore, corresponding to WGA membrane staining, α2 isoforms were found to colocalize with t-tubules. These finding suggested that alteration of Na/K ATPase pump function occurs early in the progression of hypertrophy toward heart failure, and α2 isoforms may play a more prominent role in regulating Ca handling.Open Acces
Route choice behavior of freeway travelers under realtime traffic information provisionâapplication of the best route and the habitual route choice mechanisms
The route choice behaviour on freeways between Taipei and Taichung in Taiwan under real-time traffic information provision is investigated. Two types of route choice mechanisms (the best-route and habitual-route) are analysed using ordered probit models to identify the major influences on freeway travellersâ route choice behaviour. The level of service associated with each route is defined as a generalized cost saving and specified non-linearly with a spline-like threshold inherent to travellers. The marginal (dis)utility thresholds in the âbestâ and âhabitualâ behaviour models are identified through a grid search assessed on overall goodness of fit. The findings from this study provide a better understanding of the effects of Advanced Traveller Information Systems on driversâ route choice behaviour, and a useful reference when planning for the provision of realtime information for drivers
San-Huang-Xie-Xin-Tang Prevents Rat Hearts from Ischemia/Reperfusion-Induced Apoptosis through eNOS and MAPK Pathways
San-Huang-Xie-Xin-Tang (SHXT) is a traditional Chinese medication consisting of three herbs, namely Coptidis rhizome, Scutellariae radix and Rhei rhizome. This study aimed to examine the cardioprotective effects of SHXT in a rat model of acute myocardial apoptosis induced by ischemia/reperfusion (I/R). Vehicle (intravenous saline) or SHXT (intravenous or oral) was administered prior to I/R (occlusion of left coronary artery for 45âmin followed by reperfusion for 2âh). In the vehicle group, myocardial I/R caused myocardial infarction with increased plasma cardiac enzymes, severe arrhythmia and mortality. Myocardial apoptosis was induced by I/R as evidenced by DNA ladder and Bcl-2/Bax ratio. In the SHXT group, we found that SHXT significantly reduced plasma levels of cardiac enzymes, arrhythmia scores (from 5 ± 1 to 2 ± 1, P < .01) and mortality rate (from 53 to 0%, P < .01). In addition, pretreatment with intravenous SHXT reduced the infarct size dose-dependently when compared with the vehicle group (10âmgâkgâ1: 14.0 ± 0.2 versus 44.5 ± 5.0%, and 30âmgâkgâ1: 6.2 ± 1.2% versus 44.5 ± 5.0%, both P < .01). Similarly, oral administration of SHXT reduced the infarct size dose-dependently. Furthermore, SHXT markedly decreased the apoptosis induced by I/R with increased Bcl-2/Bax ratio. Finally, we found that SHXT counteracted the I/R-induced downstream signaling, resulting in increased myocardial eNOS expression and plasma nitrite, and decreased activation of ERK1/2, p38 and JNK. These data suggest that SHXT has cardioprotective effects against I/R-induced apoptosis, and that these effects are mediated, at least in part, by eNOS and MAPK pathways
Spontaneous Dissecting Aneurysm of the Renal Artery: A Case Report
Primary dissecting aneurysms of the renal artery are exceedingly rare. The triad of flank pain, hematuria, and hypertension of acute onset in the absence of urinary obstruction should suggest this rare condition. We report a case of spontaneous dissecting aneurysm of the renal artery treated using conservative medical treatment. The diagnosis, therapeutic management, and outcome are discussed
Can probability of genetic mutation be an indicator of clinical relevance?
AbstractNPM1 gene mutation evaluated on a population basis is a valuable and realistic tool to reflect the pathophysiological relevance of cancer. In a comparison of the NPM1 cDNA of human bladder cancer with its consensus sequence, we have found that a higher NPM1 sequence identity in a population is consistent with poor tumor differentiation, advanced tumor stage, and likelihood of recurrence. These data imply that âprobabilityâ of NPM1 mutation is an indicator of status of malignancy
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