Recent anecdotal evidence has suggested that Lake Diefenbaker, a large reservoir in southern Saskatchewan, Canada, has been experiencing an increased frequency and severity of algal blooms, suggesting significant alterations in water quality. Due to limited historical water quality monitoring, a paleolimnological investigation of Lake Diefenbaker sediments was conducted in order to interpret spatial and temporal trends in the physicochemistry of sediment cores collected from mid-channel locations along a spatial gradient. Total phosphorus and three sediment species of phosphorus (apatite inorganic phosphorus, non-apatite inorganic phosphorus (NAIP) and organic phosphorus (OP) were measured along the vertical profile of the cores to interpret nutrient loading trends. Trends in historical primary productivity were inferred based on total organic carbon, total nitrogen, δ15N values and the organic carbon to nitrogen (C:N) ratios. In addition, sub-fossil biological remains of diatoms and chironomid larvae were isolated from selected subsections of the sediment cores and identified to assess shifts in community compositions and to infer historical changes in reservoir water quality conditions. Up-reservoir sampling locations showed consistent concentrations of total phosphorus and the three species of phosphorus, organic carbon, nitrogen, δ15N values and C:N ratios in the vertical profile of collected sediment cores. This suggested relatively consistent nutrient loading and primary production in the up-reservoir regions for the period represented by the core profiles. Down-reservoir sediment cores showed an increasing trend in total phosphorus concentration, mainly in the more biologically available NAIP and OP fractions, and enrichment in organic carbon, nitrogen and 15N in more recently deposited sediments. This combined with a decreasing C:N ratio in more recent sediments suggests increased nutrient loading to the sediments and increasing primary productivity at down-reservoir sites. Strong correlations between sediment total organic carbon content and the more biologically available sediment phosphorus fractions (NAIP and OP) suggest that phosphorus deposition patterns are strongly influenced by primary productivity within the reservoir. The compositions of diatom and chironomid communities were consistent over time at up-reservoir locations, with Stephanodiscus parvus dominating the diatom communities and Procladius sp. dominating the chironomid communities. This suggests relatively stable and consistent trophic status and primary productivity in this region. Conversely, major shifts occurred in the diatom and benthic chironomid communities at down-reservoir locations. These shifts were consistent with typical reservoir ontogeny. A shift in dominance from Stephanodiscus parvus to Asterionella formosa, Tabellaria flocculosa and Stephanodiscus medius followed by a shift to Aulacosiera ambigua suggests an initial period of eutrophy, followed by a period of mesotrophy, and finally a transition into a more productive system in recent years. The increase in relative abundance of the chironomid tribe Tanytarsini suggests rising levels of organic matter sedimentation, likely due to increased autochthonous primary productivity. Low chironomid head capsule counts were observed at all locations within Lake Diefenbaker. Despite the low head capsule counts, a 10-day whole-sediment toxicity test using Chironomus dilutus, revealed that Lake Diefenbaker sediments, in proximity to two potential point sources of contamination (aquaculture and municipal discharge), as well as two reference locations, were not of toxicological concern. Despite the lack of toxicity associated with Lake Diefenbaker sediments, it was concluded that Lake Diefenbaker sediments are likely poor habitat for chironomids. This study suggests that primary productivity and nutrient status has remained relatively constant at up-reservoir locations for the period represented by the collected cores. This is likely due to up-reservoir locations being more riverine than down-reservoir regions, which results in increased turbidity causing phytoplankton populations to be light limited. Primary productivity appears to increase spatially with increased distance down reservoir, likely due to a gradual transition to more lacustrine environments, resulting in less turbidity and less light limitation. Temporally, down-reservoir locations appear to be showing increases in primary productivity and nutrient entrainment in sediments. This is likely a result of increased nutrient availability over time and entrainment of these nutrients in sediments at down-reservoir locations by primary producers.

Technology scaling of CMOS devices has made the integrated circuits vulnerable to single event radiation effects. Scaling of CMOS Static RAM (SRAM) has led to denser packing architectures by reducing the size and spacing of diffusion nodes. However, this trend has led to the increase in charge collection and sharing effects between devices during an ion strike, making the circuit even more vulnerable to a specific single event effect called the single event multiple-node upset (SEMU). In nanometer technologies, SEMU can easily disrupt the data stored in the memory and can be more hazardous than a single event single-node upset. During the last decade, most of the research efforts were mainly focused on improving the single event single-node upset tolerance of SRAM cells by using novel circuit techniques, but recent studies relating to angular radiation sensitivity has revealed the importance of SEMU and Multi Bit Upset (MBU) tolerance for SRAM cells. The research focuses on improving SEMU tolerance of CMOS SRAM cells by using novel circuit and layout level techniques. A novel SRAM cell circuit & layout technique is proposed to improve the SEMU tolerance of 6T SRAM cells with decreasing feature size, making it an ideal candidate for future technologies. The layout is based on strategically positioning diffusion nodes in such a way as to provide charge cancellation among nodes during SEMU radiation strikes, instead of charge build-up. The new design & layout technique can improve the SEMU tolerance levels by up to 20 times without sacrificing on area overhead and hence is suitable for high density SRAM designs in commercial applications. Finally, laser testing of SRAM based configuration memory of a Xilinx Virtex-5 FPGA is performed to analyze the behavior of SRAM based systems towards radiation strikes.

The purpose of this study was to describe the competencies needed by nursing intern students as identified by their preceptors and nurse educators, who choose to work as registered nurses in intensive care units in Saudi Arabia. The research questions this study investigated were 1) what do nurse preceptors and nurse educators believe are the competencies for new graduates to allow them to work safely in an intensive care unit in Saudi Arabia, 2) what are the competencies they should possess at the end of their internships. 3) Is there a difference between nurse educators and preceptors in the perception of required or expected competencies of the nursing role in the Intensive Care Unit (ICU)? Through the Interpretive Description methodology, data were collected through interviews, the guide for which was developed based on the Canadian Association of Critical Care Nurses standards for critical care nursing practice. The data were analyzed to identify common themes. Themes for intensive care unit competencies included: 1) needed skill competencies; 2) development of knowledge application competencies; and 3) strategies for quality improvement. A notable aspect of this study was the finding that Saudi Arabia, there was agreement among participants that nursing intern students were not prepared to work in ICU immediately after their internship year. Building on participants’ responses, nursing intern students may acquire satisfactory preparation during their internship through continuous evaluation, consistent guidance, extended time period, and orientation. Consequently, it represents a significant contribution to enriching the nursing intern students’ internship outcomes as well as the literature in the context of Saudi Arabia and in advancing the nursing workforce in Intensive Care Units in Saudi Arabia.

Head Start, an early intervention program administered by the Administration for Children and Families of the Department of Health and Human Services, offers children of low-income families comprehensive services in an effort to even the playing field with their more advantaged peers upon entering kindergarten. Despite the many areas that Head Start addresses, evaluative efforts continuously focus primarily on cognitive gains as a result of Head Start as an intervention. This study examined the potential long-term effects of the health component of Head Start. More specifically, the study investigated whether Head Start impacts a family?s ability to make positive changes in the home in the way of preventive health measures with regard to childhood obesity, immunizations, and dental health, three important areas of childhood health. Participants in the research study included children enrolled in Head Start between 2004 and 2006, and children on the waiting list within the same time. Followup interviews were conducted with families in both groups that inquired about health behaviors specifically related to childhood obesity, immunizations, and dental health. The Head Start (HS) Group and Waiting List Control (WLC) Group were compared to determine if Head Start made a difference in a family?s probability of engaging in more proactive health measures. Responses of the HS Group were also compared with responses from their initial health assessment upon enrolling in Head Start to determine if they demonstrate positive changes. Results did not support hypotheses, and in many instances the WLC Group demonstrated better proactive health measures than the HS Group. Because of operational difficulties, there is limited inference about the impact of the Head Start program. Possible contributors to the results include a small sample size due to the mobility of the target population and overrepresentation of Hispanic children in the study. Limited differences observed between the HS and WLC groups confirms the importance of further investigating the long-term impact of Head Start in areas other than cognitive gains.

The architectures of the control devices in active control algorithm are an important fact in civil structural buildings. Traditional research has limitations in finding the optimal architecture of control devices such as using predefined numbers or locations of sensors and dampers within the 2-and 3-dimensional (3-D) model of the structure. Previous research using single-objective optimization only provides limited data for defining the architecture of sensors and control devices. The Linear Quadratic Gaussian (LQG) control algorithm is used as the active control strategy. The American Society of Civil Engineers (ASCE) control benchmark building definition is used to develop the building system model. The proposed gene manipulation genetic algorithm (GMGA) determines the near-optimal Pareto fronts which consist of varying numbers and locations of sensors and control devices for controlling the ASCE benchmark building by considering multi-objectives such as interstory drift and minimizing the number of the control devices. The proposed GMGA reduced the central processing unit (CPU) run time and produced more optimal Pareto fronts for the 2-D and 3-D 20-story building models. Using the GMGA provided several benefits: (1) the possibility to apply any presuggested multi-objective optimization mechanism; (2) the availability to perform a objective optimization problem; (3) the adoptability of the diverse encoding provided by the GA; (4) the possibility of including the engineering judgment in generating the next generation population by using a gene creation mechanisms; and (5) the flexibility of the gene creation mechanism in applying and changing the mechanism dependent on optimization problem. The near-optimal Pareto fronts obtained offer the structural engineer a diverse choice in designing control system and installing the control devices. The locations and numbers of the dampers and sensors in each story are highly dependent on the sensor locations. By providing near-Pareto fronts of possible solutions to the engineer that also consider diverse earthquakes, the engineer can get normalized patterns of architectures of control devices and sensors about random earthquakes.

Loss is an inevitable part of the human experience. How each individual reacts to loss may be affected by various factors (e.g. an individual’s attachment style). The current studies focused on how individuals respond to and cope with the loss of one type of attachment figure, specifically the loss of a romantic partner. The relationship between romantic loss and attachment theory is discussed and an integrated model of romantic relationship loss and attachment is proposed. This model accounts for various differences in how individuals respond to the loss of romantic relationships in young adulthood. Study 1 focused on the development of a revised form of the Inventory of Daily Widowed Life (IDWL; Caserta and Lund, 2007), which was labelled the Daily Activities After Relationship Loss (DAARL), to assess loss-orientation, restoration-orientation, and the oscillation between these processes following romantic relationship loss. This measure allowed for the assessment of coping in keeping with the constructs of the Dual Process Model of Bereavement (DPM; Stroebe & Schut, 1999), but allowed for these processes to be assessed in the context of romantic relationship loss as opposed to coping following the death of a loved one. Study 1 was comprised of two parts with differing samples: Part 1 included seven (four female) graduate students and undergraduate alumni in the social sciences as participants whereas Part 2 included ninety-seven (sixty-nine female) undergraduate psychology students. Participants were presented with proposed items for the new measure, as well as definitions of loss-oriented and restoration-oriented coping, and then were asked to categorize these items as loss-oriented coping, restoration-oriented coping, both, or other. Items yielding the highest levels of inter-rater agreement were used for the DAARL in Study 2. Study 2 focussed on the attachment relationship between former romantic partners, and how individuals coped with the loss of an attachment figure following the termination of a romantic relationship. One hundred and fifty-nine (one hundred and eleven female) individuals who had been broken up with or deemed their most recent romantic loss as being a mutual break-up were asked to complete a questionnaire packet containing measures of attachment style, coping behaviours following the loss, depression, anxiety, and socially desirable responding. A model of differences in coping with romantic relationship loss based on an individual’s attachment style was proposed and tested based on Stroebe, Schut, and Stroebe’s (2005) DPM and findings by Waskowic (2010; See Figure 4). Based on the findings from the current studies there are differences between the four types of attachment (i.e., secure, dismissing, preoccupied, and fearful) in how each copes with the loss of a romantic attachment figure. In light of the current findings, a revised model of romantic grief, which integrates the Dual Process Model of Bereavement within an attachment theoretical framework is offered (See Figure 5). This new model accounts for observed differences in the way individuals cope with the loss of a romantic relationship and suggests that researchers focus on the attachment relationship to explain variability in an individual’s response following romantic loss. The results of Study 2 provide support for the new integrated model and encourage others to consider using attachment theory, when examining how individuals with different attachment styles (i.e., secure, dismissing, preoccupied, and fearful) will respond to a romantic loss. Study 1 and 2 in conjunction also provide early stage support for the validity of the DAARL. Study 1 provided initial content validity by having independent raters assess items as being consistent with restoration-oriented or loss-oriented coping. Study 2 provided empirical support of the items selected as being consistent with their intended constructs by analyzing internal consistency and item-total correlations. The findings of Study 2 suggested that the dimensions proposed represented related, but distinct constructs. The current studies aimed to advance our understanding of the relationship between attachment theory and romantic relationship loss by expanding upon relevant theories and empirical findings for bereavement following a death to other forms of loss. Further, the findings are reported in regards to specific attachment styles, rather than the secure versus insecure distinction that has been commonly utilized when conducting research on attachment style differences. Implications and future directions for research are discussed.

Weighted group algebras have been studied extensively in Abstract Harmonic Analysis.Complete characterizations have been found for some important properties of weighted group algebras, namely, amenability and Arens regularity. Also studies on some other features of these algebras, say weak amenability and isomorphism to operator algebras, have attracted attention. Hypergroups are generalized versions of locally compact groups. When a discrete group has all its conjugacy classes finite, the set of all conjugacy classes forms a discrete commutative hypergroup. Also the set of equivalence classes of irreducible unitary representations of a compact group forms a discrete commutative hypergroup. Other examples of discrete commutative hypergroups come from families of orthogonal polynomials. The center of the group algebra of a discrete finite conjugacy (FC) group can be identified with a hypergroup algebra. For a specific class of discrete FC groups, the restricted direct products of finite groups (RDPF), we study some properties of the center of the group algebra including amenability, maximal ideal space, and existence of a bounded approximate identity of maximal ideals. One of the generalizations of weighted group algebras which may be considered is weighted hypergroup algebras. Defining weighted hypergroups, analogous to weighted groups, we study a variety of examples, features and applications of weighted hypergroup algebras. We investigate some properties of these algebras including: dual Banach algebra structure, Arens regularity, and isomorphism with operator algebras. We define and study Folner type conditions for hypergroups. We study the relation of the Folner type conditions with other amenability properties of hypergroups. We also demonstrate some results obtained from the Leptin condition for Fourier algebras of certain hypergroups. Highlighting these tools, we specially study the Leptin condition on duals of compact groups for some specific compact groups. An application is given to Segal algebras on compact groups.

Computerized adaptive testing (CAT) provides a highly efficient alternative to the paper-and-pencil test. By selecting items that match examinees’ ability levels, CAT not only can shorten test length and administration time but it can also increase measurement precision and reduce measurement error. In CAT, maximum information (MI) is the most widely used item selection procedure. However, the major challenge with MI is the attenuation paradox, which results because the MI algorithm may lead to the selection of items that are not well targeted at an examinee’s true ability level, resulting in more errors in subsequent ability estimates. The solution is to find an alternative item selection procedure or an appropriate ability estimation method. CAT studies have not investigated the association between these two components of a CAT system based on polytomous IRT models. The present study compared the performance of four item selection procedures (MI, MPWI, MEI, and MEPV) across four ability estimation methods (MLE, WLE, EAP-N, and EAP-PS) under the mixed-format CAT based on the generalized partial credit model (GPCM). The test-unit pool and generated responses were based on test-units calibrated from an operational national test that included both independent dichotomous items and testlets. Several test conditions were manipulated: the unconstrained CAT as well as the constrained CAT in which the CCAT was used as the content-balancing, and the progressive-restricted procedure with maximum exposure rate equal to 0.19 (PR19) served as the exposure control in this study. The performance of various CAT conditions was evaluated in terms of measurement precision, exposure control properties, and the extent of selected-test-unit overlap. Results suggested that all item selection procedures, regardless of ability estimation methods, performed equally well in all evaluation indices across two CAT conditions. The MEPV procedure, however, was favorable in terms of a slightly lower maximum exposure rate, better pool utilization, and reduced test and selected-test-unit overlap than with the other three item selection procedures when both CCAT and PR19 procedures were implemented. It is not necessary to implement the sophisticated and computing-intensive Bayesian item selection procedures across ability estimation methods under the GPCM-based CAT. In terms of the ability estimation methods, MLE, WLE, and two EAP methods, regardless of item selection procedures, did not produce practical differences in all evaluation indices across two CAT conditions. The WLE method, however, generated significantly fewer non-convergent cases than did the MLE method. It was concluded that the WLE method, instead of MLE, should be considered, because the non-convergent case is less of an issue. The EAP estimation method, on the other hand, should be used with caution unless an appropriate prior θ distribution is specified. / text

Most bacteriophages release progeny virions at the end of the infection cycle by lysis of the host. Large phages with double-stranded DNA genomes use a multigene strategy based on holins, small membrane proteins, and bacteriolytic enzymes, or endolysins. Holins mediate the control of endolysin activity and thus the timing of lysis. Phages with small genomes only encode a single protein for cell lysis. There are three known unrelated single protein lysis systems: the ?X174 E protein, the MS2 L protein, and the Q? A2 protein. None of these phages encodes a cell wall degrading activity, and previous work has shown that the lytic activity of E stems from its ability to inhibit the host enzyme, MraY, which catalyzes the formation of lipid I, the first lipid intermediate in cell wall synthesis. The purpose of the work described in this dissertation was to characterize the ?X174 E-mediated inhibition of MraY using genetic and biochemical strategies. A fundamental question was why no large phages use the single gene system. This was addressed by constructing a recombinant phage, ?E, in which the holin-endolysin based lysis cassette of ? was replaced with E. ?E was compared with ? in genetic and physiological experiments, with the results indicating that the holin-endolysin system increases fitness in terms of adjusting lysis timing to environmental conditions. Using ?E, physiological experiments were conducted to characterize the interaction between E and MraY in vivo. Transmembrane domains (TMD) 5 and 9 have been identified as the potential E binding site by isolating MraY mutants resistant to E inhibition. The five Eresistant MraY mutants were found to fall into three classes, which reflect the apparent affinity of the mutant proteins for E. Finally, an assay for MraY activity employing the dansylated UDP-MurNAc-pentapeptide and phytol-P, was used to demonstrate the inhibition of MraY by purified E protein. It was determined that E is a non-competitive inhibitor for MraY in respect with both substrates. A model for E-mediated inhibition of MraY was proposed, in which E binds to TMDs 5 and 9 in MraY and thus inactivates the enzyme by inducing a conformational change.

The purpose of this study was to investigate the relative effectiveness of positive interdependence and group processing on student achievement, interaction, and attitude in online cooperative learning. All of the participants, 144 college students enrolled in one of three different courses, received initial general instruction about teamwork skills and cooperative learning at the start of the study. Participants were then randomly assigned to one of three treatment groups: positive interdependence, group processing, and no structure. The ?positive interdependence? groups received subsequent positive interdependence skills training which were then utilized in their instructional activities. The ?group processing? groups received subsequent group processing skills training for use in their instructional activities. The ?no structure? groups received no additional instructional treatment beyond the initial basic teamwork and cooperative learning training. Results indicated that there were significant differences among students in the ?positive interdependence,? ?group processing,? and ?no structure? groups with respect to their achievement scores and interactions. Participants in the ?positive interdependence? groups had significantly higher achievement than participants in either the ?group processing? groups or the ?no structure? groups. In addition, participants in the ?positive interdependence? groups and the ?group processing? groups interacted with each other to a greater extent than those in the ?no structure? groups. This study also examined the relative effectiveness of positive interdependence and group processing on types of student interaction. The results indicated that ?positive interdependence? strategies were relatively more effective than ?group processing? strategies on ?sharing and comparing of information? interactions, whereas ?group processing? strategies were relatively more effective than ?positive interdependence? strategies on ?negotiation of meaning and co-construction of knowledge? interactions. Regarding student attitude towards the experiences of cooperative learning: participation, communication resources, and online activities, there was no significant difference among any of the three groups. The overall results of this study suggest that instructors would be advised to incorporate positive interdependence strategies in their online courses to help students perceive that they should actively contribute to their online group activities. In addition, instructors are recommended to inform groups of the individual progress of each member?s activities periodically by employing group processing strategies.