Causal attributions for success or failure by passing and failing students in College Algebra

Success in mathematics has been identified as a predictor of baccalaureate degree completion. Within the coursework of college mathematics, College Algebra has been identified as a high-risk course due to its low success rates. ^ Research in the field of attribution theory and academic achievement suggests a relationship between a student's attributional style and achievement. Theorists and researchers contend that attributions influence individual reactions to success and failure. They also report that individuals use attributions to explain and justify their performance. Studies in mathematics education identify attribution theory as the theoretical orientation most suited to explain academic performance in mathematics. This study focused on the relationship among a high risk course, low success rates, and attribution by examining the difference in the attributions passing and failing students gave for their performance in College Algebra. ^ The methods for the study included a pilot administration of the Causal Dimension Scale (CDSII) which was used to conduct reliability and principal component analyses. Then, students (n = 410) self-reported their performance on an in-class test and attributed their performance along the dimensions of locus of causality, stability, personal controllability, and external controllability. They also provided open-ended attribution statements to explain the cause of their performance. The quantitative data compared the passing and failing groups and their attributions for performance on a test using One-Way ANOVA and Pearson chi square procedures. The open-ended attribution statements were coded in relation to ability, effort, task difficulty, and luck and compared using a Pearson chi square procedure. ^ The results of the quantitative data comparing passing and failing groups and their attributions along the dimensions measured by the CDSII indicated statistical significance in locus of causality, stability, and personal controllability. The results comparing the open-ended attribution statements indicated statistical significance in the categories of effort and task difficulty. ^

Epiphyte loads on seagrasses and microphytobenthos abundance are not reliable indicators of nutrient availability in oligotrophic coastal ecosystems

Despite marked gradients in nutrient availability that control the abundance and species composition of seagrasses in south Florida, and the importance of nutrient availability in controlling abundance and composition of epiphytes on seagrasses in other locations, we did not find that epiphyte load on the dominant seagrass, Thalassia testudinum, or that the relative contribution of algal epiphytes to the epiphyte community, was positively correlated with nutrient availability in the water column or the sediment in oligotrophic seagrass beds. Further, the abundance of microphytobenthos, as indicated by Chlorophyll-aconcentration in the sediments, was not directly correlated with concentrations of nutrients in the sediments. Our results suggest that epiphyte and microphytobenthos abundance are not unambiguous indicators of nutrient availability in relatively pristine seagrass environments, and therefore would make poor candidates for indicators of the status and trends of seagrass ecosystems in relatively low-nutrient environments like the Florida Keys.

History education and the construction of national identity in Iran

This study examined the representation of national and religious dimensions of Iranian history and identity in Iranian middle school history textbooks. Furthermore, through a qualitative case study in a school in the capital city of Tehran, teachers' use of textbooks in classrooms, students' response, their perceptions of the country's past, and their definitions of national identity is studied. The study follows a critical discourse analysis framework by focusing on the subjectivity of the text and examining how specific concepts, in this case collective identities, are constructed through historical narratives and how social actors, in this case students, interact with , and make sense of, the process. My definition of national identity is based on the ethnosymbolism paradigm (Smith, 2003) that accommodates both pre-modern cultural roots of a nation and the development and trajectory of modern political institutions. Two qualitative approaches of discourse analysis and case study were employed. The textbooks selected were those published by the Ministry of Education; universally used in all middle schools across the country in 2009. The case study was conducted in a girls' school in Tehran. The students who participated in the study were ninth grade students who were in their first year of high school and had just finished a complete course of Iranian history in middle school. Observations were done in history classes in all three grades of the middle school. The study findings show that textbooks present a generally negative discourse of Iran's long history as being dominated by foreign invasions and incompetent kings. At the same time, the role of Islam and Muslim clergy gradually elevates in salvaging the country from its despair throughout history, becomes prominent in modern times, and finally culminates in the Islamic Revolution as the ultimate point of victory for the Iranian people. Throughout this representation, Islam becomes increasingly dominant in the textbooks' narrative of Iranian identity and by the time of the Islamic Revolution morphs into its single most prominent element. On the other hand, the students have created their own image of Iran's history and Iranian identity that diverges from that of the textbooks especially in their recollection of modern times. They have internalized the generally negative narrative of textbooks, but have not accepted the positive role of Islam and Muslim clergy. Their notion of Iranian identity is dominated by feelings of defeat and failure, anecdotal elements of pride in the very ancient history, and a sense of passivity and helplessness.

Cooperative and adaptive medium access control in multi-hop wireless networks

Due to low cost and easy deployment, multi-hop wireless networks become a very attractive communication paradigm. However, IEEE 802.11 medium access control (MAC) protocol widely used in wireless LANs was not designed for multi-hop wireless networks. Although it can support some kinds of ad hoc network architecture, it does not function efficiently in those wireless networks with multi-hop connectivity. Therefore, our research is focused on studying the medium access control in multi-hop wireless networks. The objective is to design practical MAC layer protocols for supporting multihop wireless networks. Particularly, we try to prolong the network lifetime without degrading performances with small battery-powered devices and improve the system throughput with poor quality channels. ^ In this dissertation, we design two MAC protocols. The first one is aimed at minimizing energy-consumption without deteriorating communication activities, which provides energy efficiency, latency guarantee, adaptability and scalability in one type of multi-hop wireless networks (i.e. wireless sensor network). Methodologically, inspired by the phase transition phenomena in distributed networks, we define the wake-up probability, which maintained by each node. By using this probability, we can control the number of wireless connectivity within a local area. More specifically, we can adaptively adjust the wake-up probability based on the local network conditions to reduce energy consumption without increasing transmission latency. The second one is a cooperative MAC layer protocol for multi-hop wireless networks, which leverages multi-rate capability by cooperative transmission among multiple neighboring nodes. Moreover, for bidirectional traffic, the network throughput can be further increased by using the network coding technique. It is a very helpful complement for current rate-adaptive MAC protocols under the poor channel conditions of direct link. Finally, we give an analytical model to analyze impacts of cooperative node on the system throughput. ^