Biological activities of compounds from Piper species

It is well established that secondary metabolites play an important role in plant chemical defense. In an effort to find natural herbicides research on plant growth regulatory activity of secondary metabolites has received more and more attention recently. The genus Piper has been an important source for useful secondary metabolites.^ Crude extracts from Piper species inhibited gram-positive bacteria and higher plant growth under laboratory conditions. Bioassay-guided isolation and purification lead to the identification of safrole, a phenylpropene, as the responsible agent for the inhibitory activity. Safrole was found to leach from naturally fallen leaves with water. Mechanisms of plant growth inhibition by safrole were investigated. Disassociation of cell membrane from cell walls was determined to be a major cause.^ Phenylpropenes structurally similar to safrole had similar phytogrowth inhibitory activity. It is postulated that phenylpropanoids are an important group of naturally occurring secondary metabolites in plant-plant interactions. ^

Making Life Choices Program: A psychoeducational intervention for promoting critical cognitive and affective competencies in adolescents at-risk for problem behaviors

The long term goal of the work described is to contribute to the emerging literature of prevention science in general, and to school-based psychoeducational interventions in particular. The psychoeducational intervention reported in this study used a main effects prevention intervention model. The current study focused on promoting optimal cognitive and affective functioning. The goal of this intervention was to increase potential protective factors such as critical cognitive and communicative competencies (e.g., critical problem solving and decision making) and affective competencies (e.g., personal control and responsibility) in middle adolescents who have been identified by the school system as being at-risk for problem behaviors. The current psychoeducational intervention draws on an ongoing program of theory and research (Berman, Berman, Cass Lorente, Ferrer Wreder, Arrufat, & Kurtines 1996; Ferrer Wreder, 1996; Kurtines, Berman, Ittel, & Williamson, 1995) and extends it to include Freire's (1970) concept of transformative pedagogy in developing school-based psychoeducational programs that target troubled adolescents. The results of the quantitative and qualitative analyses indicated trends that were generally encouraging with respect to the effects of the intervention on increasing critical cognitive and affective competencies. ^

Education and training in the use of physical agent modalities by occupational therapists practicing in the physical disabilities area

This study was conducted to examine how occupational therapists (OTs) practicing in the physical disabilities area received their training in the use of physical agent modalities (PAMs); to determine the frequency of PAMs usage by those therapists; and to obtain their opinions regarding the training of OTs and OT students in the administration of PAMs. Three hundred OTs practicing in physical diabilities (n = 194 returned) were surveyed. The most frequently used modalities were hot and cold packs, paraffin, and ultrasound. The least frequently used modalities were transcutaneous electrical stimulation (TENS) and whirlpool. On-the-job training was the most common educational method received by the respondents for PAMs usage. The respondents considered a combination of undergraduate education, fieldwork, continuing education and on-the-job training as the most appropriate educational setting for training in modalities. While few of the respondents received preparation in PAMs during entry-level academic programs, the majority felt that OT students should be trained in PAMs usage as part of their education curriculum. ^

Equity policy, educational practice, and limited English proficient (LEP) students in two high schools in Miami

Most studies of language minority students' performance focus on students' characteristics. This study uses qualitative methodology to examine instead how educational policies and practices affect the tracking of language minority students who are classified as limited English proficient (LEP). The placement of LEP students in core courses (English, Math, Social Studies, and Science) is seen as resulting from the interaction between school context and student characteristics. The school context includes factors such as equity policy requirements, overcrowding, attitudes regarding immigrants' academic potential, tracking, and testing practices. Interaction among these factors frequently leads to placement in lower track courses. It was found that the absence of formal tracks could be misleading to immigrant students, particularly those with high aspirations who do not understand the implications of the informal tracking system. Findings are discussed in relation to current theoretical explanations for minority student performance. ^

The effect of self-operated prompts on leisure participation by persons with mental retardation

The use of permanent prompts for individuals with severe disabilities has been shown to be effective in acquiring new skills, improving the accuracy and maintenance of existing skills, and in eliminating the need for trainer prompts. However, this technology has not been evaluated for its potential impact in promoting leisure participation. In this study, two men with mental retardation were administered auditory and/or visual prompts to investigate their effect on increasing participation in a leisure activity. In addition, their performance was evaluated to establish whether continuous versus intermittent schedules of the prompts would influence participation. The data were collected using a partial interval observation system and evaluated using a multiple baseline and an alternating treatment design. While both men increased their participation modestly in the leisure activity, there was no substantial difference between the two prompting schedules. ^

The Cuban military in Angola: The limits of internationalism

The Cuban military involvement in Angola has often been seen as a response to the wishes of the former Soviet Union. Yet, Castro intervened in Angola following his theory of internationalism. Internationalism, as conceived by Castro, sent Cubans on a voluntary basis to serve abroad, either in the military or in the civilian sector. This thesis will illustrate that from its inception, Castro sent military troops to Angola to divert domestic concerns and to boost Cuba's alliances throughout the world. Angola is different from other internationalist missions, because in Angola--for the first time--regular combat troops were used. Castro intervened in Angola to prevent a collapse of the Moviemento Popular de Libertacao de Angola (MPLA) government, and stayed on to ensure the viability of the MPLA. The primary sources are interviews conducted by the author, of participants in the Angolan civil war. The secondary sources consulted are works on Cuba, Southern Africa, Portuguese colonialism and Angola. ^

Activity streets as economic opportunity generators: Case study of the Langa Township, Cape Town, South Africa

The Republic of South Africa since the 1948 inception of Apartheid policies has experienced economic problems resulting from spatially dispersed growth. The election of President Mandela in 1994, however, eliminated the last forms of Apartheid as well as its discriminatory spatial, social, and economic policies, specially toward black Africans. In Cape Town, South Africa, several initiatives to restructure and to economically revitalize blighted and abandoned township communities, like Langa, have been instituted. One element of this strategy is the development of activity streets. The main questions asked in this study are whether activity streets are a feasible solution to the local economic problems left by the apartheid system and whether activity streets represent an economically sustainable approach to development. An analysis of a proposed activity street in Langa and its potential to generate jobs is undertaken. An Employment Generation Model used in this study shows that many of the businesses rely on the local purchasing power of the residents. Since the economic activities are mostly service oriented, a combination of manufacturing industries and institutionally implemented strategies within the township will have to be developed in order to generate sustainable employment. The result seem to indicate that, in Langa, the activity street depend very much on an increase in sales, pedestrian and vehicular traffic flow. ^

Improving the predictability of time series by chaotic parameter estimation

Limited literature regarding parameter estimation of dynamic systems has been identified as the central-most reason for not having parametric bounds in chaotic time series. However, literature suggests that a chaotic system displays a sensitive dependence on initial conditions, and our study reveals that the behavior of chaotic system: is also sensitive to changes in parameter values. Therefore, parameter estimation technique could make it possible to establish parametric bounds on a nonlinear dynamic system underlying a given time series, which in turn can improve predictability. By extracting the relationship between parametric bounds and predictability, we implemented chaos-based models for improving prediction in time series. ^ This study describes work done to establish bounds on a set of unknown parameters. Our research results reveal that by establishing parametric bounds, it is possible to improve the predictability of any time series, although the dynamics or the mathematical model of that series is not known apriori. In our attempt to improve the predictability of various time series, we have established the bounds for a set of unknown parameters. These are: (i) the embedding dimension to unfold a set of observation in the phase space, (ii) the time delay to use for a series, (iii) the number of neighborhood points to use for avoiding detection of false neighborhood and, (iv) the local polynomial to build numerical interpolation functions from one region to another. Using these bounds, we are able to get better predictability in chaotic time series than previously reported. In addition, the developments of this dissertation can establish a theoretical framework to investigate predictability in time series from the system-dynamics point of view. ^ In closing, our procedure significantly reduces the computer resource usage, as the search method is refined and efficient. Finally, the uniqueness of our method lies in its ability to extract chaotic dynamics inherent in non-linear time series by observing its values. ^

Radially rotating miniature heat pipes for turbine blade cooling applications

Aerospace turboengines present a demanding challenge to many heat transfer scientists and engineers. Designers in this field are seeking the best design to transform the chemical energy of the fuel into the useful work of propulsive thrust at maximum efficiency. To this aim, aerospace turboengines must operate at very high temperatures and pressures with very little heat losses. These requirements are often in conflict with the ability to protect the turboengine blades from this hostile thermal environment. Heat pipe technology provides a potential cooling means for the structure exposed to high heat fluxes. Therefore, the objective of this dissertation is to develop a new radially rotating miniature heat pipe, which would combine the traditional air-cooling technology with the heat pipe for more effective turboengine blade cooling. ^ In this dissertation, radially rotating miniature heat pipes are analyzed and studied by employing appropriate flow and heat transfer modeling as well as experimental tests. The analytical solutions for the flows of condensate film and vapor, film thickness, and vapor temperature distribution along the heat pipe length are derived. The diffuse effects of non-condensable gases on the temperature distribution along the heat pipe length are also studied, and the analytical solutions for the temperature distributions with the diffuse effects of non-condensable gases are obtained. Extensive experimental tests on radially rotating miniature heat pipes with different influential parameters are undertaken, and various effects of these parameters on the operation of the heat pipe performance are researched. These analytical solutions are in good agreement with the experimental data. ^ The theoretical and experimental studies have proven that the radially rotating miniature heat pipe has a very large heat transfer capability and a very high effective thermal conductance that is 60–100 times higher than the thermal conductivity of copper. At the same time, the heat pipe has a simple structure and low manufacturing cost, and can withstand strong vibrations and work in a high-temperature environment. Therefore, the combination of the traditional air-cooling technology with the radially rotating miniature heat pipe is a feasible and effective cooling means for high-temperature turbine blades. ^

Determinants of confidence and their effect on epistemic judgments: Implications for auditor calibration bias

Auditor decisions regarding the causes of accounting misstatements can have an audit effectiveness and efficiency. Specifically, overconfidence in one's decision can lead to an ineffective audit, whereas underconfidence in one's decision can lead to an inefficient audit. This dissertation explored the implications of providing various types of information cues to decision-makers regarding an Analytical Procedure task and investigated the relationship between different types of evidence cues (confirming, disconfirming, redundant or non-redundant) and the reduction in calibration bias. Information was collected using a laboratory experiment, from 45 accounting students participants. Research questions were analyzed using a 2 x 2 x 2 between-subject and within-subject analysis of covariance (ANCOVA). ^ Results indicated that presenting subjects with information cues dissimilar to the choice they made is an effective intervention in reducing the common overconfidence found in decision-making. In addition, other information characteristics, specifically non-redundant information can help in reducing a decision-maker's overconfidence/calibration bias for difficulty (compared to easy) decision-tasks. ^

An aquatic risk assessment of ethion and bromacil inputs to the C-25 Canal and Indian River Lagoon

Pesticide monitoring in St. Lucie County by various local, state and federal agencies has indicated consistent residues of several pesticides, including ethion and bromacil. Although pesticides have long been known to pose a threat to non-target species and much background monitoring has been done, no pesticide aquatic risk assessment has been done in this geographical area. Several recognized United States Environmental Protection Agency (USEPA) methods of quantifying risk are employed here to include hazard quotients (HQ) and probabilistic modeling with sensitivity analysis. These methods are employed to characterize potential impacts to aquatic biota of the C-25 Canal and the Indian River Lagoon (in St. Lucie County, Florida) based on current agricultural pesticide use and drainage patterns. The model used in the analysis incorporates available physical-chemical property data, local hydrology, ecosystem information, and pesticide use practices. HQ's, probabilistic distributions, and field sample analyses resulted in high levels of concern (LOCs), which usually indicates a need for regulatory action, including restrictions on use, or cancellation. ^

Pilot study: Intranet communication among chronically ill hospitalized pediatric individuals

Hospitalization can be a very stressful experience, especially for children. With the use of technology, Intranet communication can be successful in obtaining interaction that these individuals lack to accomplish a positive adjustment to the hospital setting. The purpose of this exploratory, pilot project is to examine the use of networking chronically ill, hospitalized children with other hospitalized chronically ill children through Intranet communication.^ A target population of chronically ill hospitalized children, in at least Piaget's concrete operational stage, was asked to use the Intranet system to network with other chronically ill hospitalized children during their hospital stay, for one month or until discharge. The length of time of usage was recorded on a log sheet, and questionnaires were filled out at the end of the study.^ Statistical analysis was utilized to determine frequency of network usage, duration, demographics, and the impact on hospitalization. Results indicated that Intranet communication between chronically ill hospitalized children was utilized by the participants from 7-15 age groups; and had a positive impact on their hospitalization. ^

Factors affecting emergency department length of stay of patients admitted to telemetry and critical care units

The purpose of this study was to determine the emergency department (ED) length of stay (LOS) of patients admitted to inpatient telemetry and critical care units and to identify the factors that contribute to a prolonged ED LOS. It also examined whether there was a difference in ED LOS between clients evaluated by an ED physician, an Advanced Registered Nurse Practitioner (ARNP) or a Physician's Assistant (PA).^ A data collection tool was devised and used to record data obtained by retrospectively reviewing 110 charts of patients from this sample. The mean ED LOS was 286.75 minutes. Multiple factors were recorded as affecting the ED LOS of this sample, including: age, diagnosis, consultations, multiple radiographs, pending admission orders, nurse unable to call report/busy, relatives at bedside, observation or stabilization necessary, bed not ready and infusion in progress. No significant difference in ED LOS was noted between subjects initially evaluated by a physician, an ARNP or a PA. ^

The relationship between self-esteem and job performance

The purpose of this study was to conduct a meta-analysis of the relationship between self-esteem and job performance. Overall, 49 studies were gathered and coded by their sample size, correlation estimate, and the reliability of the two measures being correlated. The data was processed using the interactive meta-analysis program called INTNL, which takes into account interactive effects between the artifacts (i.e., unreliability in the independent and dependent measures as well as sampling error). Analyses of four potential moderators were examined--type of self-esteem, the source of job performance, the type of setting and the type of self-esteem measures. Results indicated that the relationship between self-esteem and job performance is positive. However, there was only a weak support for moderating influences. Procedures to enhance employees' self-esteem are recommended. ^

Consumer (dis)satisfaction response to disconfirmation: An examination of the form and the underlying process

The purpose of this dissertation was to examine the form of the consumer satisfaction/dissatisfaction (CS/D) response to disconfirmation. In addition, the cognitive and affective processes underlying the response were also explored. ^ Respondents were provided with information from a prior market research study about a new brand of printer that was being tested. This market research information helped set prior expectations regarding the print quality. Subjects were randomly assigned to an experimental condition that manipulated prior expectations to be either positive or negative. Respondents were then provided with printouts that had performance quality that was either worse (negative disconfirmation) or better (positive disconfirmation) than the prior expectations. In other words, for each level of expectation, respondents were assigned to either positive or negative disconfirmation condition. Subjects were also randomly assigned to a condition of either a high or low level of outcome involvement. ^ Analyses of variance indicated that positive disconfirmation led to a more intense CS/D response than negative disconfirmation, even though there was no significant difference in the intensity for positive and negative disconfirmation. Intensity of CS/D was measured by the distance of the CS/D rating from the midpoint of the scale. The study also found that although outcome involvement did not influence the polarity of the CS/D response, the more direct measures of processing involvement such as the subjects' concentration, attention and care in evaluating the printout did have a significant positive effect on CS/D intensity. ^ Analyses of covariance also indicated that the relationship between the intensity of the CS/D response and the intensity of the disconfirmation was mediated by the intensity of affective responses. Positive disconfirmation led to more intense affective responses than negative disconfirmation. ^