14 resultados para Second Normal Stress Difference

em Digital Commons at Florida International University


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In order to prepare younger generations to live in a world characterized by interconnectedness, developing global and international perspectives for future teachers has been recommended by the National Council for the Social Studies and the National Council for the Accreditation of Teacher Education. The purpose of this study was to investigate the effects that participation in the International Communication and Negotiation Simulation (ICONS), an Internet-based communication project has on preservice social studies teachers' global knowledge, global mindedness, and global teaching strategies. ^ The study was conducted at a public university in South Florida. A combination of quantitative and qualitative approaches was employed. Two groups of preservice social studies teachers were chosen as participants: a control group composed of 14 preservice teachers who enrolled in a global education class in the summer semester of 1998 and an experimental group that included nine preservice teachers who took the same class in the fall semester of 1998. The summer class was conducted in a traditional format, which included lectures, classroom discussions, and student presentations. The fall class incorporated a five-week Internet-based communication project. The Global Mindedness Scale (Hett, 1993) and an adapted Test of Global Knowledge (ETS, 1981) were administered upon the completion of the class. ^ Contrasting case studies were utilized to investigate the impact of participation in the ICONS on the development of preservice teachers' global pedagogy. Four preservice teachers, two selected from each group were observed and interviewed to explore how they were infusing global perspectives into social studies curriculum and instruction during a 10-week student teaching internship in the spring semester of 1999. ^ This study had three major findings. First, preservice social studies teachers from the experimental group on average scored significantly higher than those from the control group on the global knowledge test. Second, no significant difference was found between the two groups in their mean scores on the Global Mindedness Scale. Third, all four selected preservice social studies teachers were infusing global perspectives into United States and world history curriculum and instruction during their student teaching internship. Using multiple resources was the common pedagogy. The two who participated in the ICONS were more aware of using the communication feature of the Internet and the web sites that reflect more international perspectives to facilitate teaching about the world. ^ Recommendations were made for further research and for preservice studies teacher education program development. ^

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The purpose of this study was threefold. The primary purpose was to develop a stress profile for teachers in private schools. This study also addressed two exploratory issues. The first, consisted of an examination of the possible differences in the levels of on-the-job stress among teachers in different types of private schools. A second issue was to discuss the findings on private school in light of the extant literature on public schools, specifically using the data collected by Fimain to develop the Teacher Stress Inventory. This study was conducted utilizing 316 full time teachers from seven schools from six different states.^ The instrument employed in this study was the Teacher Stress Inventory (TSI) developed by Fimian (1988). The TSI is a 10 factor, 49 item self-report measure. The 10 factors consist of five Stress Sources and five Stress measure. The 10 factors consist of five Stress Sources and five Stress Manifestations subscales. The mean for these 10 factors yields the stress construct termed "Total Stress." Of the 437 surveys mailed, 316 usable surveys, i.e., 72.3%, were returned.^ The results suggest that private school teachers experience moderate levels of stress. The mean score was 2.27 indicating a lower than average stress level as measured by the TSI. Comparisons between types of private schools revealed that there were no significant differences between the stress levels of teachers in boarding and nonboarding schools. Teachers in large schools experience significantly higher levels of stress than teachers in small and medium size schools. However, the measurable difference between them translates into a very small difference in terms of the real stress levels of these teachers in their professional lives. A significant difference was also found between the stress levels of public $(M=2.60)$ and private school teachers $(M=2.27).$ Both means fall within the moderate range, however, while private school teachers experience lower than average levels of stress, the stress levels of teachers in public schools falls in the higher than average range.^ Recommendations for reducing stress levels in both private and public schools are presented as well as suggestions for future research. ^

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Purpose: Over half the HIV-infected persons in the Caribbean, the second most HIV-impacted region in the world, live in Haiti. Using secondary data from a parent study, this research assessed the effects of psychological and social factors on antiretroviral therapy (ART) adherence among Haitian, HIV-positive, female alcohol users. Theoretical Foundation and Research Questions: Using the Theory of Planned Behavior/Reasoned Action and the Information, Motivation, Behavior skills model as guiding theoretical frameworks, the study examined the effectiveness of an adapted cognitive behavioral stress management (CBSM-A) intervention in improving ART adherence. The effect of psychological factors (depression, anxiety, beliefs about medicine, and social support), social factors (stigma, relationship status, and educational attainment), and alcohol on adherence to ART was assessed. Methods: The sample consisted of 116 female ART patients who were randomly assigned to the CBSM-A intervention or the wait-list control group. Participants completed intervention sessions as well as pre- and post-test assessments. Analyses of variance, t-tests, and point biserial correlations were used to test hypotheses. Results: Surprisingly, ART adherence rates significantly decreased for both groups combined [F (1, 108) = 8.79, p = .004]; there was no significant difference between the intervention and control groups with regard to the magnitude of change between baseline and post assessment. On average, depression decreased significantly among participants in the CBSM-A group only [(t (62) = 5.54, p < .001)]. For both groups combined, alcohol use significantly decreased between baseline and post-assessment [(F (1, 78) = 34.70, p < .001)]; there was no significant difference between the intervention and control groups with regard to the magnitude of change between baseline and post-assessment. None of the variables were significantly correlated with ART adherence. Discussion: Adherence to ART did not improve in this sample, nor were any of the variables significantly associated with adherence. The findings suggest that additional supportive and psychological services may be needed in order to promote higher adherence to ART among HIV-positive females. More research may be needed on this sample; a focus on mental health issues, partner conflict, family and sexual history may allow for better targeting and more successful interventions.

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Prices of U.S. Treasury securities vary over time and across maturities. When the market in Treasurys is sufficiently complete and frictionless, these prices may be modeled by a function time and maturity. A cross-section of this function for time held fixed is called the yield curve; the aggregate of these sections is the evolution of the yield curve. This dissertation studies aspects of this evolution. ^ There are two complementary approaches to the study of yield curve evolution here. The first is principal components analysis; the second is wavelet analysis. In both approaches both the time and maturity variables are discretized. In principal components analysis the vectors of yield curve shifts are viewed as observations of a multivariate normal distribution. The resulting covariance matrix is diagonalized; the resulting eigenvalues and eigenvectors (the principal components) are used to draw inferences about the yield curve evolution. ^ In wavelet analysis, the vectors of shifts are resolved into hierarchies of localized fundamental shifts (wavelets) that leave specified global properties invariant (average change and duration change). The hierarchies relate to the degree of localization with movements restricted to a single maturity at the base and general movements at the apex. Second generation wavelet techniques allow better adaptation of the model to economic observables. Statistically, the wavelet approach is inherently nonparametric while the wavelets themselves are better adapted to describing a complete market. ^ Principal components analysis provides information on the dimension of the yield curve process. While there is no clear demarkation between operative factors and noise, the top six principal components pick up 99% of total interest rate variation 95% of the time. An economically justified basis of this process is hard to find; for example a simple linear model will not suffice for the first principal component and the shape of this component is nonstationary. ^ Wavelet analysis works more directly with yield curve observations than principal components analysis. In fact the complete process from bond data to multiresolution is presented, including the dedicated Perl programs and the details of the portfolio metrics and specially adapted wavelet construction. The result is more robust statistics which provide balance to the more fragile principal components analysis. ^

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Antenna design is an iterative process in which structures are analyzed and changed to comply with certain performance parameters required. The classic approach starts with analyzing a "known" structure, obtaining the value of its performance parameter and changing this structure until the "target" value is achieved. This process relies on having an initial structure, which follows some known or "intuitive" patterns already familiar to the designer. The purpose of this research was to develop a method of designing UWB antennas. What is new in this proposal is that the design process is reversed: the designer will start with the target performance parameter and obtain a structure as the result of the design process. This method provided a new way to replicate and optimize existing performance parameters. The base of the method was the use of a Genetic Algorithm (GA) adapted to the format of the chromosome that will be evaluated by the Electromagnetic (EM) solver. For the electromagnetic study we used XFDTD™ program, based in the Finite-Difference Time-Domain technique. The programming portion of the method was created under the MatLab environment, which serves as the interface for converting chromosomes, file formats and transferring of data between the XFDTD™ and GA. A high level of customization had to be written into the code to work with the specific files generated by the XFDTD™ program. Two types of cost functions were evaluated; the first one seeking broadband performance within the UWB band, and the second one searching for curve replication of a reference geometry. The performance of the method was evaluated considering the speed provided by the computer resources used. Balance between accuracy, data file size and speed of execution was achieved by defining parameters in the GA code as well as changing the internal parameters of the XFDTD™ projects. The results showed that the GA produced geometries that were analyzed by the XFDTD™ program and changed following the search criteria until reaching the target value of the cost function. Results also showed how the parameters can change the search criteria and influence the running of the code to provide a variety of geometries.

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The purpose of this research project was to investigate two distinct types of research questions – one theoretical, the other empirical: (1) What would justice mean in the context of the international trade regime? (2.Using the small developing states of the Commonwealth Caribbean as a case study, what do Commonwealth Caribbean trade negotiators mean when they appeal to justice? Regarding the first question, Iris Young's framework which focuses on the achievement of social justice in a domestic context by acknowledging social differences such as those based on race and gender, was adopted and its relevance argued in the international context of interstate trade negotiation so as to validate the notion of (size, location, and governance capacity) difference in this latter context. The point of departure is that while states are typically treated as equals in international law – as are individuals in liberal political theory – there are significant differences between states which warrant different treatment in the international arena. The study found that this re-formulation of justice which takes account of such differences between states, allows for more adequate policy responses than those offered by the presumption of equal treatment. Regarding the second question, this theoretical perspective was used to analyze the understandings of justice from which Commonwealth Caribbean trade negotiators proceed. Interpretive and ethnographic methods, including participant observation, interviews, field notes, and textual analysis, were employed to analyze their understandings of justice. The study found that these negotiators perceive such justice as being justice to difference because of the distinct characteristics of small developing states which combine to constrain their participation in the international trading system; based on this perception, they seek rules and outcomes in the multilateral trade regime which are sensitive to such different characteristics; and while these issues were examined in a specific region, its findings are relevant for other regions consisting of small developing states, such as those in the ACP group.

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Coral reefs are declining worldwide due to increased incidence of climate-induced coral bleaching, which will have widespread biodiversity and economic impacts. A simple method to measure the sub-bleaching level of heat-light stress experienced by corals would greatly inform reef management practices by making it possible to assess the distribution of bleaching risks among individual reef sites. Gene expression analysis based on quantitative PCR (qPCR) can be used as a diagnostic tool to determine coral condition in situ. We evaluated the expression of 13 candidate genes during heat-light stress in a common Caribbean coral Porites astreoides, and observed strong and consistent changes in gene expression in two independent experiments. Furthermore, we found that the apparent return to baseline expression levels during a recovery phase was rapid, despite visible signs of colony bleaching. We show that the response to acute heat-light stress in P. astreoides can be monitored by measuring the difference in expression of only two genes: Hsp16 and actin. We demonstrate that this assay discriminates between corals sampled from two field sites experiencing different temperatures. We also show that the assay is applicable to an Indo-Pacific congener, P. lobata, and therefore could potentially be used to diagnose acute heat-light stress on coral reefs worldwide.

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Immigrants from Jamaica represent the largest number of migrants to the United States from the English speaking Caribbean. Research indicates that of all Caribbean immigrants they are most likely to retain the ethnic identity of their home country for the longest period of time. This dissertation explored the nature of ethnic identity and sought to determine its impact upon the additional variables of self-esteem and academic factors. A secondary analysis was carried out using data collected in the Spring of 1992 by Portes and Rumbaut on the children of immigrants attending the eighth and ninth grades in local schools in San Diego and southern Florida. A sample of 151 second-generation Jamaican immigrants was selected from the data set. ^ Six hypotheses yielded mixed results. Both parents who have a Jamaican ethnic identity present in the household are the best predictor Jamaican youth who retain a Jamaican ethnic identity. It was expected that ethnic identity would be a predictor of positive academic factors. The study showed that ethnic identity was not associated with one of the academic factors which were examined: help given with homework. ^ Neither family economic status nor parents' level of education played a significant role in the retention of Jamaican identity. Other findings were that there was no mean difference in the self-esteem scores of respondents who had similar ethnic identities to their parents and those who did not. There was also no difference found in the academic factors of either group. The study also showed that there was a small correlation between parent-child conflict and self-esteem. Specifically, the study found that the higher the conflict between youth and their parents, the lower the self-esteem of the youth. Finally it found that time lived in the U.S. was the best predictor of a higher GPA and it was also related to lower self-esteem. ^ Surprisingly, the study found that the relationship between ethnic identity and SES was the opposite of what was expected in that it found that SES was higher when there was no Jamaican identity. ^

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The adverse health effects of long-term exposure to lead are well established, with major uptake into the human body occurring mainly through oral ingestion by young children. Lead-based paint was frequently used in homes built before 1978, particularly in inner-city areas. Minority populations experience the effects of lead poisoning disproportionately. ^ Lead-based paint abatement is costly. In the United States, residents of about 400,000 homes, occupied by 900,000 young children, lack the means to correct lead-based paint hazards. The magnitude of this problem demands research on affordable methods of hazard control. One method is encapsulation, defined as any covering or coating that acts as a permanent barrier between the lead-based paint surface and the environment. ^ Two encapsulants were tested for reliability and effective life span through an accelerated lifetime experiment that applied stresses exceeding those encountered under normal use conditions. The resulting time-to-failure data were used to extrapolate the failure time under conditions of normal use. Statistical analysis and models of the test data allow forecasting of long-term reliability relative to the 20-year encapsulation requirement. Typical housing material specimens simulating walls and doors coated with lead-based paint were overstressed before encapsulation. A second, un-aged set was also tested. Specimens were monitored after the stress test with a surface chemical testing pad to identify the presence of lead breaking through the encapsulant. ^ Graphical analysis proposed by Shapiro and Meeker and the general log-linear model developed by Cox were used to obtain results. Findings for the 80% reliability time to failure varied, with close to 21 years of life under normal use conditions for encapsulant A. The application of product A on the aged gypsum and aged wood substrates yielded slightly lower times. Encapsulant B had an 80% reliable life of 19.78 years. ^ This study reveals that encapsulation technologies can offer safe and effective control of lead-based paint hazards and may be less expensive than other options. The U.S. Department of Health and Human Services and the CDC are committed to eliminating childhood lead poisoning by 2010. This ambitious target is feasible, provided there is an efficient application of innovative technology, a goal to which this study aims to contribute. ^

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The demise of reef-building corals potentially lies on the horizon, given ongoing climate change amid other anthropogenic environmental stressors. If corals cannot acclimatize or adapt to changing conditions, dramatic declines in the extent and health of the living reefs are expected within the next half century. The primary and proximal global threat to corals is climate change. Reef-building corals are dependent upon a nutritional symbiosis with photosynthetic dinoflagellates belonging to the group Symbiodinium. . The symbiosis between the cnidarian host and algal partner is a stress-sensitive relationship; temperatures just 1°C above normal thermal maxima can result in the breakdown of the symbiosis, resulting in coral bleaching (the loss of Symbiodinium and/or associated photopigments) and ultimately, colony death. As ocean temperatures continue to rise, corals will either acclimatize or adapt to changing conditions, or will perish. By experimentally preconditioning the coral Acropora millepora via sublethal heat treatment, the coral acquired thermal tolerance, resisting bleaching during subsequent hyperthermal stress. The complex nature of the coral holobiont translates to multiple possible explanations for acclimatization: acquired thermal tolerance could potentially originate from the host itself, the Symbiodinium, or from the bacterial community associated with the coral. By examining the type of in hospite Symbiodinium and the bacterial community prior acclimation and after thermal challenge, it is shown that short-term acclimatization is not due to a distinct change in the dinoflagellate or prokaryote community. Though the microbial partnerships remain without considerable flux in preconditioned corals, the host transcriptome is dynamic. One dominant pattern was the apparent tuning of gene expression observed between preconditioned and non-preconditioned treatments, showing a modulated transcriptomic response to stress. Additionally several genes were upregulated in association with thermal tolerance, including antiapoptotic genes, lectins, and oxidative stress response genes. Upstream of two of these thermal tolerance genes, inhibitor of NFκB and mannose-binding lectin, DNA polymorphisms were identified which vary significantly between the northern and southern Great Barrier Reef. The impact of these mutations in putative promoter regions remains to be seen, but variation across thermally-disparate geography serves to generate hypotheses regarding the role of regulatory element evolution in a coral adaptation context.

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Individual cues to deception are subtle and often missed by lay people and law enforcement alike. Linguistic statement analysis remains a potentially useful way of overcoming individual diagnostic limitations (e.g. Criteria based Content Analysis; Steller & Köhnken, 1989; Reality monitoring; Johnson & Raye, 1981; Scientific Content Analysis; Sapir, 1996). Unfortunately many of these procedures are time-consuming, require in-depth training, as well as lack empirical support and/or external validity. The current dissertation develops a novel approach to statement veracity analysis that is simple to learn, easy to administer, theoretically sound, and empirically validated. Two strategies were proposed for detecting differences between liars' and truth-tellers' statements. Liars were hypothesized to strategically write statements with the goal of self-exoneration. Liars' statements were predicted to contain more first person pronouns and fewer third person pronouns. Truth-tellers were hypothesized to be motivated toward being informative and thus produce statements with fewer first person pronouns and more third person pronouns. Three studies were conducted to test this hypothesis. The first study explored the verbal patterns of exoneration and informativeness focused statements. The second study used a traditional theft paradigm to examine these verbal patterns in guilty liars and innocent truth tellers. In the third study to better match the context of a criminal investigation a cheating paradigm was used in which spontaneous lying was induced and written statements were taken. Support for the first person pronoun hypothesis was found. Limited support was found for the third person pronoun hypothesis. Results, implications, and future directions for the current research are discussed.

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A two-dimensional, 2D, finite-difference time-domain (FDTD) method is used to analyze two different models of multi-conductor transmission lines (MTL). The first model is a two-conductor MTL and the second is a threeconductor MTL. Apart from the MTL's, a three-dimensional, 3D, FDTD method is used to analyze a three-patch microstrip parasitic array. While the MTL analysis is entirely in time-domain, the microstrip parasitic array is a study of scattering parameter Sn in the frequency-domain. The results clearly indicate that FDTD is an efficient and accurate tool to model and analyze multiconductor transmission line as well as microstrip antennas and arrays.

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The primary purpose of this study was to evaluate the effects of a single bout of moderate-intensity exercise on acute (ad libitum lunch) post-exercise energy intake (PE-EI) and 12-hour energy intake in normal-weight and overweight sedentary males. Accuracy in estimating energy intake (EI) and energy expenditure (EE), solid vs. liquid carbohydrate intake, mood, and perceived hunger were also assessed. The study consisted of two conditions, exercise and rest, with each subject participating in each condition, in a counterbalanced-crossover design on two days. The participants were randomly assigned to either the exercise or resting (seated) control condition on the first day of the experiment, and then the condition was reversed on the second day. Exercise consisted of walking on a treadmill at moderate-intensity for 60 minutes. Eighty males, mean age 30+8 years were categorized into five groups according to weight status (overweight/normal-weight), dietary restraint status (high/low), and dieting status (yes/no). The main effects of condition and group, and the interaction were not significant for acute (lunch) or 12-hour PE-EI. Overall, participants estimated EE for exercise at 46% higher than actual exercise EE, and they estimated EE for rest by 45% lower than actual resting EE. Participants significantly underestimated EI at lunch on both the exercise and rest days by 43% and 44%, respectively. Participants with high restraint were significantly better at estimating EE on the exercise day, and better at estimating EI on the rest day. Mood, perceived hunger, and solid vs. liquid carbohydrate intake were not influenced by dietary restraint, weight, or dieting status. In conclusion, a single bout of moderate-intensity exercise did not influence PE-EI in sedentary males in reference to dietary restraint, weight, and dieting status. Results also suggested that among sedentary males, there is a general inability to accurately estimate calories for moderate-intensity physical activity and EI. Inaccurate estimates of EE and EI have the potential to influence how males manage their weight.

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Design and analysis of conceptually different cooling systems for the human heart preservation are numerically investigated. A heart cooling container with required connections was designed for a normal size human heart. A three-dimensional, high resolution human heart geometric model obtained from CT-angio data was used for simulations. Nine different cooling designs are introduced in this research. The first cooling design (Case 1) used a cooling gelatin only outside of the heart. In the second cooling design (Case 2), the internal parts of the heart were cooled via pumping a cooling liquid inside both the heart’s pulmonary and systemic circulation systems. An unsteady conjugate heat transfer analysis is performed to simulate the temperature field variations within the heart during the cooling process. Case 3 simulated the currently used cooling method in which the coolant is stagnant. Case 4 was a combination of Case 1 and Case 2. A linear thermoelasticity analysis was performed to assess the stresses applied on the heart during the cooling process. In Cases 5 through 9, the coolant solution was used for both internal and external cooling. For external circulation in Case 5 and Case 6, two inlets and two outlets were designed on the walls of the cooling container. Case 5 used laminar flows for coolant circulations inside and outside of the heart. Effects of turbulent flow on cooling of the heart were studied in Case 6. In Case 7, an additional inlet was designed on the cooling container wall to create a jet impinging the hot region of the heart’s wall. Unsteady periodic inlet velocities were applied in Case 8 and Case 9. The average temperature of the heart in Case 5 was +5.0oC after 1500 s of cooling. Multi-objective constrained optimization was performed for Case 5. Inlet velocities for two internal and one external coolant circulations were the three design variables for optimization. Minimizing the average temperature of the heart, wall shear stress and total volumetric flow rates were the three objectives. The only constraint was to keep von Mises stress below the ultimate tensile stress of the heart’s tissue.