Investigating Problems Posed by Pre-Service Mathematics Teachers for the Four Operations in Fractions

This study investigates 40 preservice middle school teachers’ problems posed for two given fractions. Pre-service teachers were asked to pose three problems (farea, length and set model) for each of the operations of addition, subtraction, multiplication and division with these fractions. 12 problems posed by each pre-service teacher were examined in terms of their suitability for the given operation, the targeted model and real life relevance. Errors in the posed problems were also examined. As a result of the analysis, it was observed that the model in which pre-service teachers were the most unsuccessful in posing problems was the set model, and the model in which they were most successful was the length model. Many types of errors were encountered in the problems posed by the pre-service teachers. It has been observed that many errors exist together, especially in the problems posed for the set model

Fuel Efficiency Assessment with DEA

In this study, Data Envelopment Analysis (DEA) is used to calculate Air Mobility Command (AMC) airlift fuel efficiency for C-17 aircraft. Fuel is a strategic asset for the United States Air Force and suitable alternatives are not yet feasible or available in the quantity required. The Air Force is pursuing several initiatives to conserve energy and operate more efficiently while sustaining the same level of effectiveness and safety. In order to manage these initiatives, it must measure how well it is doing. To measure airlift efficiency, the AMC Fuel Efficiency Office established a 7 factor weighted Fuel Efficiency Index (FEI). To produce a monthly score, AMC assigned weights for each factor. DEA does not require such a priori assumptions and finds the best set of weights that will help each mission to represent itself in the best manner. The results showed that DEA and FEI agree in trends but a DEA Slack-Based Measure better differentiates inefficiencies than other methods used in the study. Also, the results showed that for current Air Mobility flights, at least 10% input excess or output shortfall occurs each month

Cross-Border Mergers and Acquisitions and Country Risk Ratings: Evidence from U.S. Financials

This study reports how country risk and macroeconomic conditions influence the wealth gains of U.S. financial firms involved in international mergers and takeovers. The findings suggest that U.S. financials experience weakly significant wealth gains around announcement date. The wealth gains are significant for takeovers in Latin America. There are also differences in wealth gains of subsector affiliations of financial firms. While banks experiencing wealth loss, both insurance and investment services firms having significant wealth gains. The country risk, including economic, political, and financial risk ratings, help to explain the wealth gains to financial bidders

Investigating Preservice Mathematics Teachers’ Definitions, Formulas, and Graphs of Directly and Inversely Proportional Relationships

This study investigates 48 preservice middle school teachers’ formal textbook definitions, formulas, and graphs of the directly and inversely proportional relationships. The connections among these three types of representations and how preservice teachers’ representations differ according to the two relationships are also examined. The data of the study included the preservice teachers’ responses to a paper-and-pencil test with two items. An explanatory research design model was followed when developing this study. The study findings indicated the preservice teachers’ over-attention to the simultaneous increases and/or decreases when representing the directly and inversely proportional relationships. Only four preservice teachers stated in their definitions that the ratio was constant in the directly proportional relationship. Whereas none of them stated constant product in their inversely proportional definition. Although the preservice teachers were slightly better at writing the direct proportion formula than the inverse proportion formula, this difference was much greater in terms of drawing the direct and inverse proportion graphs. Sixty percent of the preservice teachers drew their inverse proportion graphs as linear with negative slopes. Moreover, the analysis showed that the preservice teachers’ definitions were not well-linked with their graphs and formulas. On the other hand, the preservice teachers who were better at providing correct formulas were also better at drawing the correct graphs. Implications for teaching and future study suggestions are discussed

On the meaning of “the meaning of life”

When it comes to a question as notoriously unclear as “What is the meaning of life?” clarifying the question and its conceptual setting is a necessary step before attempting to answer the question. The analysis of the concept of “the meaning of life” is a twofold task; “the meaning” and “life” both need to be examined. In this paper, I primarily focus on “the meaning”. I argue that, although there is much disagreement and confusion in the literature about the meaning of “the meaning” as it is applied to life, there is one most plausible interpretation of this notion. In the end, even though I do not answer the question of the meaning of life, I propose an account of what a correct answer to the question is supposed to look like, based on my original function analysis of “the meaning.

Sobre o significado do “sentido da vida”

When it comes to a question as notoriously unclear as “What is the meaning of life?”, clarifying the question and its conceptual setting is a necessary step before attempting to answer the question. The analysis of the concept of “the meaning of life” is a twofold task; “the meaning” and “life” both need to be examined. In this paper, I primarily focus on “the meaning.” I argue that, although there is much disagreement and confusion in the literature about the meaning of “the meaning” as it is applied to life, there is one most plausible interpretation of this notion. In the end, even though I do not answer the question of the meaning of life, I propose an account of what a correct answer to the question is supposed to look like, based on my original function analysis of “the meaning.”Keywords: the meaning of life, meaningfulness, meaning in life. No tocante a uma questão notoriamente pouco clara como “Qual é o sentido da vida?”, esclarecer a questão e seu marco conceitual é um passo necessário antes de tentar respondê-la. A análise do conceito “o sentido da vida” implica uma tarefa dupla: tanto “o sentido” quanto “vida” precisam ser examinados. Neste artigo, enfoco primordialmente o termo “o sentido”. Sustento que, embora haja muita divergência e confusão na literatura sobre o significado de “o sentido” quando este termo é aplicado à vida, há uma interpretação mais plausível dessa noção. No fim, embora não respondendo a questão do sentido da vida, apresento uma proposta de como poderia ser uma resposta correta a essa questão, com base em minha análise da função original de “o sentido”.Palavras-chave: o sentido da vida, significatividade, sentido na vida

The day of the week effect on stock market volatility

This study tests the presence of the day of the week effect on stock market volatility by using the S&P 500 market index during the period of January 1973 and October 1997. The findings show that the day of the week effect is present in both volatility and return equations. While the highest and lowest returns are observed on Wednesday and Monday, the highest and the lowest volatility are observed on Friday and Wednesday, respectively. Further investigation of sub-periods reinforces our findings that the volatility pattern across the days of the week is statistically different

Hizmet İşletmelerinde Maliyetleme Sisteminin Tasarımı1 Design Of Costing System In Service Operations

Kendi içinde çok sayıda ve birbirinden farklı alt sektörlerden oluşan hizmet işletmelerinde doğru maliyet bilgisine ulaşma ihtiyacı her zaman önemli olmuştur. Ancak günümüzde bu hizmet türlerinin büyük bölümünün küresel rekabetle karşı karşıya kalmaları bu ihtiyacı daha fazla artmıştır. Hizmet sektörünün dünyadaki birçok gelişmiş ülkenin gayri safi yurtiçi hasılasına olan artan katkısına rağmen, hizmet maliyeti konusunda yapılan akademik çalışmalar oldukça kısıtlıdır. Çalışmada hizmet işletmelerinde maliyetlemenin doğasında olan zorluklar ortaya konularak, uygun bir sınıflama ile hizmet işletmelerinde kullanılması gereken maliyetleme yöntemlerinin neler olabileceği ortaya çıkarılmıştır. Bu çalışma ile mevcut sınırlı literatürdeki bilginin sentezlenerek hizmet işletmelerinde maliyetleme konusunda ilgi duyan akademik ve uygulamaya dönük araştırmacılara yol göstermesi hedeflenmektedir. The need to reach the right cost information in service businesses, which consist of numerous and different sub-sectors within themselves, has always been important. However, nowadays, most of these types of services have to face global competition and this need has increased more. Despite the growing contribution of the service sector to the gross domestic product of many developed countries in the world, the academic studies on service cost is rather limited. The purpose of this study is to discuss the costing methods that should be applied as a result of an appropriate classification, with the difficulties encountered in the costing of service enterprises. The aim of this study is to synthesize the information in existing limited literature and to lead academic and practical researchers who are interested in costing in service enterprises

Spontaneous Rapid Resolution of Acute Epidural Hematoma in Childhood

Acute epidural hematoma is a critical emergency all around the world, and its aggressive diagnosis and treatment are of vital importance. Emergent surgical evacuation of the hematoma is known as standard management; however, conservative procedures are also used for small ones. Spontaneous rapid resolution of these hematomas has also been reported in eight pediatric cases. Various theories have been proposed to explain the underlying pathophysiology of this resolution. Herein, we are reporting a new pediatric case with spontaneously resolving acute epidural hematoma 12 hours after admission to the emergency room