877 resultados para Physical-Mathematical Modes of Perception
Resumo:
The idea of comparative performance assessment is crucial. Recent study findings show that in South Florida the use by most municipalities of external benchmarks for performance comparison is virtually non-existent. On one level this study sought to identify the factors impacting resident perceptions of municipal service quality. On a different and more practical level, this study sought to identify a core set of measures that could serve for multi jurisdictional comparisons of performance. ^ This study empirically tested three groups of hypotheses. Data were collected via custom designed survey instruments from multiple jurisdictions, representing diverse socioeconomic backgrounds, and across two counties. A second layer of analysis was conducted on municipal budget documents for the presence of performance measures. A third layer of analysis was conducted via face-to-face interviews with residents at the point of service delivery. Research questions were analyzed using descriptive and inferential statistic methodologies. ^ Results of survey data yielded inconsistent findings. In absolute aggregated terms, the use of sociological determinants to guide inquiry failed to yield conclusive answers regarding the factors impacting resident perceptions of municipal service quality. At disaggregated community levels, however, definite differences emerged but these had weak predictive ability. More useful were the findings of performance measures reporting via municipal budget documents and analyses of interviews with residents at the point of service delivery. Regardless of socio-economic profile, neighborhood characteristics, level of civic engagement or type of community, the same aspects were important to citizens when making assessments of service quality. For parks and recreation, respondents most frequently cited maintenance, facility amenities, and program offerings as important while for garbage collection services timely and consistent service delivery mattered most. Surprisingly municipalities participating in the study track performance data on items indicated as important by citizen assessments but regular feed back from residents or reporting to the same is rarely done. ^ The implications of these findings suggest that endeavors, such as the one undertaken in this study, can assist in determining a core set of measures for cross jurisdictional comparisons of municipal service quality, improving municipal delivery of services, and to communicate with the public. ^
Resumo:
Diet and physical activity patterns have been implicated as major factors in the increasing prevalence of childhood and adolescent obesity. It is estimated that between 16 and 33 percent of children and adolescents in the United States are overweight (CDC, 2000). Moreover, the CDC estimates that less than 50% of adolescents are physically active on a regular basis (CDC, 2003). Interventions must be focused to modify these behaviors. Facilitating the understanding of proper nutrition and need for physical activity among adolescents is the first step in preventing overweight and obesity and delaying the development of chronic diseases later in life (Dwyer, 2000). The purpose of this study was to compare the outcomes of students receiving one of two forms of education (both emphasizing diet and physical activity), to determine whether a computer based intervention (CBI) program using an interactive, animated CD-ROM would elicit a greater behavior change in comparison to a traditional didactic intervention (TDI) program. A convenience sample of 254 high school students aged 14-19 participated in the 6-month program. A pre-test post-test design was used, with follow-up measures taken at three months post-intervention. ^ No change was noted in total fat, saturated fat, fruit/vegetables, or fiber intake for any of the groups. There was also no change in perceived self-efficacy or perceived social support. Results did, however, indicate an increase in nutrition knowledge for both intervention groups (p<0.001). In addition, the CBI group demonstrated more positive and sustained behavior changes throughout the course of the study. These changes included a decrease in BMI (ppre/post<0.001, ppost/follow-up<0.001), number of meals skipped (ppre/post<0.001), and soda consumption (ppre/post=0.003, ppost/follow-up=0.03) and an increase in nutrition knowledge (ppre/post<0.001, ppre/follow-up <0.001), physical activity (ppre/post<0.05, p pre/follow-up<0.01), frequency of label reading (ppre/follow-up <0.0l) and in dairy consumption (ppre/post=0.03). The TDI group did show positive gains in some areas post intervention, however a return to baseline behavior was shown at follow-up. Findings of this study suggest that compared to traditional didactic teaching, computer-based nutrition and health education has greater potential to elicit change in knowledge and behavior as well as promote maintenance of the behavior change over time. ^
Resumo:
Shipboard power systems have different characteristics than the utility power systems. In the Shipboard power system it is crucial that the systems and equipment work at their peak performance levels. One of the most demanding aspects for simulations of the Shipboard Power Systems is to connect the device under test to a real-time simulated dynamic equivalent and in an environment with actual hardware in the Loop (HIL). The real time simulations can be achieved by using multi-distributed modeling concept, in which the global system model is distributed over several processors through a communication link. The advantage of this approach is that it permits the gradual change from pure simulation to actual application. In order to perform system studies in such an environment physical phase variable models of different components of the shipboard power system were developed using operational parameters obtained from finite element (FE) analysis. These models were developed for two types of studies low and high frequency studies. Low frequency studies are used to examine the shipboard power systems behavior under load switching, and faults. High-frequency studies were used to predict abnormal conditions due to overvoltage, and components harmonic behavior. Different experiments were conducted to validate the developed models. The Simulation and experiment results show excellent agreement. The shipboard power systems components behavior under internal faults was investigated using FE analysis. This developed technique is very curial in the Shipboard power systems faults detection due to the lack of comprehensive fault test databases. A wavelet based methodology for feature extraction of the shipboard power systems current signals was developed for harmonic and fault diagnosis studies. This modeling methodology can be utilized to evaluate and predicate the NPS components future behavior in the design stage which will reduce the development cycles, cut overall cost, prevent failures, and test each subsystem exhaustively before integrating it into the system.
Resumo:
Background: Both eating disorders and body image dissatisfaction affect a high proportion of college students. Self-esteem and self-efficacy may be protective factors for eating disorders. The aim of this study was to evaluate diet self-efficacy, the confidence to maintain or lose weight, and its association with physical selfconcept using data from an online survey of health literacy, body image, and eating disorders. Study Population and Methods: This cross-sectional study collected online survey data from college students within the United States. The inclusion criteria allowed for 1612 college students, ages 17-35 years (597 males, 1015 females) belonging to the following racial/ethnic categories: Black (187); White, non-Hispanic (244), Hispanic (1035), and other (146). Specifically, the study aimed to examine (a) whether and to what degree diet self-efficacy and physical self-concept were associated with risk of eating disorders; (b) the interaction of gender by ethnicity on diet self-efficacy, physical self-concept and risk of eating disorders; and, (c) the relationship of diet self-efficacy with physical self-description and body mass index (BMI) in college students. Results:Low diet self-efficacy was associated with a lower score on physical self-concept (B = −0.52 [−0.90, −0.15], P = 0.007). Males had a higher physical self-concept as compared to females (B = 14.0 [8.2, 19.8], P Conclusion: College students in this study who had a poor body image were less confident with diet control. Poorer body image and low diet selfefficacy were associated with higher BMI. These findings suggest lifestyle management interventions may be of value to improve physical self-concept and lower risk of eating disorders for college students.
Resumo:
Shipboard power systems have different characteristics than the utility power systems. In the Shipboard power system it is crucial that the systems and equipment work at their peak performance levels. One of the most demanding aspects for simulations of the Shipboard Power Systems is to connect the device under test to a real-time simulated dynamic equivalent and in an environment with actual hardware in the Loop (HIL). The real time simulations can be achieved by using multi-distributed modeling concept, in which the global system model is distributed over several processors through a communication link. The advantage of this approach is that it permits the gradual change from pure simulation to actual application. In order to perform system studies in such an environment physical phase variable models of different components of the shipboard power system were developed using operational parameters obtained from finite element (FE) analysis. These models were developed for two types of studies low and high frequency studies. Low frequency studies are used to examine the shipboard power systems behavior under load switching, and faults. High-frequency studies were used to predict abnormal conditions due to overvoltage, and components harmonic behavior. Different experiments were conducted to validate the developed models. The Simulation and experiment results show excellent agreement. The shipboard power systems components behavior under internal faults was investigated using FE analysis. This developed technique is very curial in the Shipboard power systems faults detection due to the lack of comprehensive fault test databases. A wavelet based methodology for feature extraction of the shipboard power systems current signals was developed for harmonic and fault diagnosis studies. This modeling methodology can be utilized to evaluate and predicate the NPS components future behavior in the design stage which will reduce the development cycles, cut overall cost, prevent failures, and test each subsystem exhaustively before integrating it into the system.
Resumo:
Pyrite formation within and directly below sapropels in the eastern Mediterranean was governed by the relative rates of sulphide production and Fe liberation and supply to the organic-rich layers. At times of relatively high [SO4]2- reduction, sulphide could diffuse downward from the sapropel and formed pyrite in underlying sediments. The sources of Fe for pyrite formation comprised detrital Fe and diagenetically liberated Fe(II) from sapropel-underlying sediments. In organic-rich sapropels, input of Fe from the water column via Fe sulphide formation in the water may have been important as well. Rapid pyrite formation at high saturation levels resulted in the formation of framboidal pyrite within the sapropels, whereas below the sapropels slow euhedral pyrite formation at low saturation levels occurred. d34S values of pyrite are -33 per mil to -50 per mil. Below the sapropels d34S is lower than within the sapropels, as a result of increased sulphide re-oxidation at times of relatively high sulphide production and concentration when sulphide could escape from the sediment. The percentage of initially formed sulphide that was re-oxidized was estimated from organic carbon fluxes and burial efficiencies in the sediment. It ranges from 34% to 80%, varying significantly between sapropels. Increased palaeoproductivity as well as enhanced preservation contributed to magnified accumulation of organic matter in sapropels.
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Nel presente lavoro, ho studiato e trovato le soluzioni esatte di un modello matematico applicato ai recettori cellulari della famiglia delle integrine. Nel modello le integrine sono considerate come un sistema a due livelli, attivo e non attivo. Quando le integrine si trovano nello stato inattivo possono diffondere nella membrana, mentre quando si trovano nello stato attivo risultano cristallizzate nella membrana, incapaci di diffondere. La variazione di concentrazione nella superficie cellulare di una sostanza chiamata attivatore dà luogo all’attivazione delle integrine. Inoltre, questi eterodimeri possono legare una molecola inibitrice con funzioni di controllo e regolazione, che chiameremo v, la quale, legandosi al recettore, fa aumentare la produzione della sostanza attizzatrice, che chiameremo u. In questo modo si innesca un meccanismo di retroazione positiva. L’inibitore v regola il meccanismo di produzione di u, ed assume, pertanto, il ruolo di modulatore. Infatti, grazie a questo sistema di fine regolazione il meccanismo di feedback positivo è in grado di autolimitarsi. Si costruisce poi un modello di equazioni differenziali partendo dalle semplici reazioni chimiche coinvolte. Una volta che il sistema di equazioni è impostato, si possono desumere le soluzioni per le concentrazioni dell’inibitore e dell’attivatore per un caso particolare dei parametri. Infine, si può eseguire un test per vedere cosa predice il modello in termini di integrine. Per farlo, ho utilizzato un’attivazione del tipo funzione gradino e l’ho inserita nel sistema, valutando la dinamica dei recettori. Si ottiene in questo modo un risultato in accordo con le previsioni: le integrine legate si trovano soprattutto ai limiti della zona attivata, mentre le integrine libere vengono a mancare nella zona attivata.
Resumo:
Conventional reliability models for parallel systems are not applicable for the analysis of parallel systems with load transfer and sharing. In this short communication, firstly, the dependent failures of parallel systems are analyzed, and the reliability model of load-sharing parallel system is presented based on Miner cumulative damage theory and the full probability formula. Secondly, the parallel system reliability is calculated by Monte Carlo simulation when the component life follows the Weibull distribution. The research result shows that the proposed reliability mathematical model could analyze and evaluate the reliability of parallel systems in the presence of load transfer.
Resumo:
In perifusion cell cultures, the culture medium flows continuously through a chamber containing immobilized cells and the effluent is collected at the end. In our main applications, gonadotropin releasing hormone (GnRH) or oxytocin is introduced into the chamber as the input. They stimulate the cells to secrete luteinizing hormone (LH), which is collected in the effluent. To relate the effluent LH concentration to the cellular processes producing it, we develop and analyze a mathematical model consisting of coupled partial differential equations describing the intracellular signaling and the movement of substances in the cell chamber. We analyze three different data sets and give cellular mechanisms that explain the data. Our model indicates that two negative feedback loops, one fast and one slow, are needed to explain the data and we give their biological bases. We demonstrate that different LH outcomes in oxytocin and GnRH stimulations might originate from different receptor dynamics. We analyze the model to understand the influence of parameters, like the rate of the medium flow or the fraction collection time, on the experimental outcomes. We investigate how the rate of binding and dissociation of the input hormone to and from its receptor influence its movement down the chamber. Finally, we formulate and analyze simpler models that allow us to predict the distortion of a square pulse due to hormone-receptor interactions and to estimate parameters using perifusion data. We show that in the limit of high binding and dissociation the square pulse moves as a diffusing Gaussian and in this limit the biological parameters can be estimated.
Resumo:
Introduction: Current physical activity levels among children and youth are alarmingly low; a mere 7% of children and youth are meeting the Canadian Physical Activity Guidelines (Colley et al., 2011), which means that the vast majority of this population is at risk of developing major health problems in adulthood (Janssen & Leblanc, 2010). These high inactivity rates may be related to suboptimal experiences in sport and physical activity stemming from a lack of competence and confidence (Lubans, Morgan, Cliff, Barnett, & Okely, 2010). Developing a foundation of physical literacy can encourage and maintain lifelong physical activity, yet this does not always occur naturally as a part of human growth (Hardman, 2011). An ideal setting to foster the growth and development of physical literacy is physical education class. Physical education class can offer all children and youth an equal opportunity to learn and practice the skills needed to be active for life (Hardman, 2011). Elementary school teachers are responsible for delivering the physical education curriculum, and it is important to understand their will and capacity as the implementing agents of physical literacy development curriculum (McLaughlin, 1987). Purpose: The purpose of this study was to explore the physical literacy component of the 2015 Ontario Health and Physical Education curriculum policy through the eyes of key informants, and to explore the resources available for the implementation of this new policy. Methods: Qualitative interviews were conducted with seven key informants of the curriculum policy development, including two teachers. In tandem with the interviews, a resource inventory and curriculum review were conducted to assess the content and availability of physical literacy resources. All data were analyzed through the lens of Hogwood and Gunn’s (1984) 10 preconditions for policy implementation. Results: Participants discussed how implementation is affected by: accountability, external capacity, internal capacity, awareness and understanding of physical literacy, implementation expertise, and policy climate. Discussion: Participants voiced similar opinions on most issues, and the overall lack of attention given to physical education programs in schools will continue to be a major dilemma when trying to combat such high physical inactivity levels.
Resumo:
New immigrants to Canada are generally in similar or better physical and mental health than people born in Canada, however, many studies suggest that their health tends to decline quickly after immigration. Lower physical activity levels among new immigrants might be contributing to this phenomenon. There is a paucity of information regarding the physical activity behaviour of the Canadian immigrant population in general and of West Asian women, such as Iranians (Persians), in particular. Given that this group is characterised by an increasing population growth and lower rates of physical activity, it is critical to understand how best to address physical activity promotion in this population. Purpose: To understand the physical activity experiences of Persian women recently immigrated to Toronto, Canada in order to develop recommendations for the design and implementation of tailored physical activity programs. Methods: A qualitative interpretive description approach was chosen to collect and describe ideas, experiences, and perceptions of physical activity within 10 new immigrant women. Using an inductive approach, two fundamental techniques of immersion and crystallization were used throughout the analysis. Thematic analysis was conducted by performing a sequential process of open and axial coding. Emerged themes were further conceptualized through a socio-ecological lens. Results: The facilitators and barriers to physical activity among the women were situated within five overarching categories, 1) Perceptions about physical activity, 2) New physical environment and social structure, 3) Cultural heritage values, 4) Settlement and immigration factors, and 5) Physical activity program features. Discussion: Findings revealed that Persian new immigrant women’s engagement in physical activity after immigration is influenced by factors across the individual, sociocultural, environmental, institutional, and policy levels. Newcomer women’s physical activity was influenced by their transition from their society of origin to the host society and the challenges and successes experienced throughout the settlement and acculturation process. The most noticeable barrier to physical activity in Canada for the women emerged as the lack of communication of physical activity information to newcomers. A set of recommendations is provided for developing efficient physical activity programs for Persian immigrant women, which may also be relevant for other immigrant groups in Canada.
Resumo:
We report the self-assembly of a new family of hydrophobic,bis(pyridyl) PtII complexes featuring an extendedoligophenyleneethynylene-derived π-surface appended withsix long (dodecyloxy (2)) or short (methoxy (3)) side groups.Complex 2, containing dodecyloxy chains, forms fibrous assemblies with a slipped arrangement of the monomer units (dPt···Pt… =14 Å) in both nonpolar solvents and the solid state.Dispersion-corrected PM6 calculations suggest that this organizationis driven by cooperative π–π, C-H···Cl and π–Pt interactions, which is supported by EXAFS and 2D NMR spectroscopic analysis. In contrast, nearly parallel π-stacks (dPt···Pt… = 4.4 Å) stabilized by multiple π–π and C-H···Cl contact sare obtained in the crystalline state for 3 lacking longside chains, as shown by X-ray analysis and PM6 calculations.Our results reveal not only the key role of alkyl chain lengthin controlling self-assembly modes but also show the relevanceof Pt-bound chlorine ligands as new supramolecular synthons.
Resumo:
Otto-von-Guericke-Universität Magdeburg, Fakultät für Mathematik, Dissertation, 2016