The Motivation of Eighth Grade Students When They Learn the Parallelogram Subject in a Computerized Environment

The goal of the current study is to examine the impact of the computerized technological environment on the motivation of eighth graders while learning the subject of parallelogram, and whether there are differences in the level of motivation of students who studied parallelogram in a computerized environment and those who studied the same subject in a traditional school environment. The use of the semi-experimental descriptive analytical curriculum, which consisted of a sample of (30) eighth grade students who were selected in a deliberate manner was implemented. The main study tool is a set of pretests and posttests, along with a computerized intervention unit that is meant to enhance students’ motivation. The results of the study clearly indicate that the involvement of the computerized environment contributed to raising the students’ level of mastery of parallelogram as a subject in eighth graders by raising internal motivation. In light of the findings of the study, the researcher recommends adopting the results of the research, handling the computerized environment as an integral part of the educational system, and qualifying the teacher to be able to actively work within a computerized environment

Efficient and Privacy-Preserving Ride Sharing Organization for Transferable and Non-Transferable Services

Ride-sharing allows multiple persons to share their trips together in one vehicle instead of using multiple vehicles. This can reduce the number of vehicles in the street, which consequently can reduce air pollution, traffic congestion and transportation cost. However, a ride-sharing organization requires passengers to report sensitive location information about their trips to a trip organizing server (TOS) which creates a serious privacy issue. In addition, existing ride-sharing schemes are non-flexible, i.e., they require a driver and a rider to have exactly the same trip to share a ride. Moreover, they are non-scalable, i.e., inefficient if applied to large geographic areas. In this paper, we propose two efficient privacy-preserving ride-sharing organization schemes for Non-transferable Ride-sharing Services (NRS) and Transferable Ride-sharing Services (TRS). In the NRS scheme, a rider can share a ride from its source to destination with only one driver whereas, in TRS scheme, a rider can transfer between multiple drivers while en route until he reaches his destination. In both schemes, the ride-sharing area is divided into a number of small geographic areas, called cells, and each cell has a unique identifier. Each driver/rider should encrypt his trip's data and send an encrypted ride-sharing offer/request to the TOS. In NRS scheme, Bloom filters are used to compactly represent the trip information before encryption. Then, the TOS can measure the similarity between the encrypted trips data to organize shared rides without revealing either the users' identities or the location information. In TRS scheme, drivers report their encrypted routes, an then the TOS builds an encrypted directed graph that is passed to a modified version of Dijkstra's shortest path algorithm to search for an optimal path of rides that can achieve a set of preferences defined by the riders

Electrolyte disorders and arrhythmogenesis

Electrolyte disorders can alter cardiac ionic currents kinetics and depending on the changes can promote proarrhythmic or antiarrhythmic effects. The present report reviews the mechanisms, electrophysiolgical (EP), electrocardiographic (ECG), and clinical consequences of electrolyte disorders. Potassium (K+) is the most abundent intracellular cation and hypokalemia is the most commont electrolyte abnormality encountered in clinical practice. The most signifcant ECG manifestation of hypokalemia is a prominent U wave. Several cardiac and non cardiac drugs are known to suppress the HERG K+ channel and hence the IK, and especially in the presence of hypokalemia, can result in prolonged action potential duration and QT interval, QTU alternans, early afterdepolarizations, and torsade de pointes ventricular tachyarrythmia (TdP VT). Hyperkalemia affects up to 8% of hospitalized patients mainly in the setting of compromised renal function. The ECG manifestation of hyperkalemia depends on serum K+ level. At 5.5–7.0 mmol/L K+, tall peaked, narrow-based T waves are seen. At > 10.0 mmol/L K+, sinus arrest, marked intraventricular conduction delay, ventricular techycardia, and ventricular fibrillation can develop. Isolated abnormalities of extracellular calcium (Ca++) produce clinically significant EP effects only when they are extreme in either direction. Hypocalcemia, frequently seen in the setting of chronic renal insufficiency, results in prolonged ST segment and QT interval while hypercalcemia, usually seen with hyperparathyroidism, results in shortening of both intervals. Although magnesium is the second most abudent intracellular cation, the significance of magnesium disorders are controversial partly because of the frequent association of other electrolyte abnormalities. However, IV magnesium by blocking the L-type Ca++ current can succesfully terminate TdP VT without affecting the prolonged QT interval. Finally, despite the frequency of sodium abnormalities, particularly hyponatremia, its EP effects are rarely clinically significant. (Cardiol J 2011; 18, 3: 233–245

The lithium-ion battery industry for electric vehicles

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 119-124).Electric vehicles have reemerged as a viable alternative means of transportation, driven by energy security concerns, pressures to mitigate climate change, and soaring energy demand. The battery component will play a key role in the adoption of these vehicles as it defines their cost, range and safety. Advances in lithium-ion battery technology are creating possibilities for electric vehicles to compete with their gasoline counterparts for the first time. However, many challenges remain, the most important of which is cost. This thesis has three main objectives. The first is to describe the evolution of the lithium-ion battery industry up to its current state. Lithium-ion battery technology was first developed in the United States and Europe. Japanese companies were the first to adopt it and commercialize it in the early 1990s, principally for electronics products. Manufacturing capabilities spread to China and Korea in the early 2000s. By the end of the first decade of this century, Southeast Asia was dominating manufacturing of lithium-ion batteries, with 98% of global production. The United States is today investing heavily to create a domestic lithium-ion battery manufacturing capability while Asian battery manufacturers are repositioning themselves to capture the market for electric vehicle batteries. The second objective of the thesis is to describe the current status of supply chain relations between automakers and battery manufacturers, and to understand how these relations might affect automakers' competitiveness. Three types of relationships are coexisting today: vertical integration, partnerships and outsourcing. Some automakers are developing battery packs in-house in vertically integrated organizations, others have forged partnerships with battery suppliers, while others have completely outsourced the development and manufacturing of the battery pack to an external supplier. Each model has its own advantages and drawbacks, and none would appear to be optimal for the entire industry as different automakers have different constraints and objectives. In the near future, knowledge of cell characteristics will be key to developing battery packs. While battery standardization is unlikely, as the technology matures firms will focus more on software and battery integration to establish their competitive edge. Finally, the thesis examines the role of government policy in the industry. Many mechanisms can be used to promote the industrial development of battery technology, both on the supply-side through research funding and the support of manufacturing, and on the demand side though regulatory standards and consumer incentives.by Sherif Kassatly.S.M

Overbite Correction and Smile Esthetics

The purpose of this prospective clinical study was to investigate differences in outcomes from two common treatment modalities used to reduce deep overbite: maxillary incisor intrusion using an intrusion arch and posterior tooth eruption using an anterior bite plate and to assess their influence on smile esthetics. Pre-treatment and post-overbite correction records were gathered from 40 patients with deep overbite malocclusions at the Virginia Commonwealth University orthodontic clinic. Intrusion arch patients displayed significant reductions in maxillary incisor display accompanying documented incisor intrusion. Bite plate patients showed significant lower incisor intrusion and increases in the mandibular plane angle. When compared to the bite plate group, there was a greater tendency for flattening of the smile arc seen in the intrusion arch group. Changes in the smile arc were likely partially a result of the mechanics used but may also have been due to other factors involved in orthodontic tooth alignment

Pathophysiology, risk stratification, and management of sudden cardiac death in coronary artery disease

Management of sudden cardiac death (SCD) is undergoing radical change in direction. It is becoming increasingly appreciated that besides depressed left ventricular systolic function and the conventional risk stratification tools, new markers for plaque vulnerability, enhanced thrombogenesis, specific genetic alterations of the autonomic nervous system, cardiac sarcolemmal and contractile proteins, and familial clustering may better segregate patients with atherosclerotic coronary artery disease (CAD) who are at high risk of SCD from those who may suffer from nonfatal ischemic events. Better understanding of pathophysiologic processes such as post-myocardial infarction remodeling, the transition from compensated hypertrophy to heart failure, and the increased cardiovascular risk of CAD in the presence of diabetes or even a pre-diabetic state will help to improve both risk stratification and management. The rapidly developing fields of microchips technology, and proteomics may allow rapid and cost-effective mass screening of multiple risk factors for SCD. The ultimate goal is not only to change the current direction of management strategy of SCD away from increased ICD utilization, but to identify novel methods for risk stratification, risk modification, and prevention of SCD that could be applied to the general public at large. (Cardiol J 2010; 17, 1: 4-10