714 resultados para barriers to change


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The objective of this study is to identify the adoption level of practices associated with more sustainable agriculture and environmentally friendly practices. Additionally, the motivations for and barriers to the adoption of these practices by farmers are investigated. Data were collected through closed questionnaires taken by a random sample of farmers in the Southwest, Sao Paulo, Brazil, during the second half of 2013. Overall, sustainable agricultural practices recommended in the literature and analysed in this study are being not fully adopted by farmers of the studied area. The results showed that financial motivation is associated with farmers adopting new, more sustainable technology, whereas the lack of information on and lack of technical support for these technologies are significant barriers. Other results, research implications, limitations and suggestions for future research are presented.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Prairie dog (Cynomys ludovicianus) control has historically consisted of lethal methods to maintain, reduce, or eliminate populations in South Dakota and throughout the species range. Non-lethal methods of control are desired to meet changing management objectives for the black-tailed prairie dog. The use of naturally occurring buffer strips as vegetative barriers may be effective in limiting prairie dog town expansion. The objectives of this study were: 1) to evaluate effective width of vegetative barriers in limiting prairie dog towns expansion in western South Dakota; and 2) to document effect native vegetation height on expansion of prairie dog towns in western South Dakota. Five study sites were established in western South Dakota on rangelands containing prairie dog towns of adequate size. Electric fences were constructed for the purpose of excluding cattle and creating buffer strips of native grasses and shrubs. Prairie dogs were poisoned to create a prairie dog free buffer zone adjacent to active prairie dog towns. Grazing was allowed on both sides of the buffer strip. When grazing pressure was not sufficient, mowing was used to simulate grazing. Buffer strips were 100 meters long and 10, 25, and 40 meters in width. A zero meter control was included on all study sites. Quadrats (25) were randomly distributed throughout the buffer strips. Evaluation of study sites included visual obstruction, vegetation cover, vegetation frequency, vegetation height, and vegetation identification. Barrier penetration was evaluated by the presence of new active burrows behind vegetative barriers. Significant relationships were documented for both VOR and vegetation height. No significant difference was found between frequency of breakthroughs and buffer widths.

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Abstract Background The responsiveness of oral health-related quality of life (OHRQoL) instruments has become relevant, given the increasing tendency to use OHRQoL measures as outcomes in clinical trials and evaluations studies. The purpose of this study was to assess the responsiveness of the Brazilian Scale of Oral Health Outcomes for 5-year-old children (SOHO-5) to dental treatment. Methods One hundred and fifty-four children and their parents completed the child self- and parental’ reports of the SOHO-5 prior to treatment and 7 to 14 days after the completion of treatment. The post-treatment questionnaire also included a global transition judgment that assessed subject’s perceptions of change in their oral health following treatment. Change scores were calculated by subtracting post-treatment SOHO-5 scores from pre-treatment scores. Longitudinal construct validity was assessed by using one-way analysis of variance to examine the association between change scores and the global transition judgments. Measures of responsiveness included standardized effect sizes (ES) and standardized response mean (SRM). Results The improvement of children’s oral health after treatment are reflected in mean pre- and post-treatment SOHO-5 scores that declined from 2.67 to 0.61 (p < 0.001) for the child-self reports, and 4.04 to 0.71 (p < 0.001) for the parental reports. Mean change scores showed a gradient in the expected direction across categories of the global transition judgment, and there were significant differences in the pre- and post-treatment scores of those who reported improving a little (p < 0.05) and those who reported improving a lot (p < 0.001). For both versions, the ES and SRM based on change scores mean for total scores and for categories of global transitions judgments were moderate to large. Conclusions The Brazilian SOHO-5 is responsive to change and can be used as an outcome indicator in future clinical trials. Both the parental and the child versions presented satisfactory results.

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We present theory and experiments on the dynamics of reaction fronts in two-dimensional, vortex-dominated flows, for both time-independent and periodically driven cases. We find that the front propagation process is controlled by one-sided barriers that are either fixed in the laboratory frame (time-independent flows) or oscillate periodically (periodically driven flows). We call these barriers burning invariant manifolds (BIMs), since their role in front propagation is analogous to that of invariant manifolds in the transport and mixing of passive impurities under advection. Theoretically, the BIMs emerge from a dynamical systems approach when the advection-reaction-diffusion dynamics is recast as an ODE for front element dynamics. Experimentally, we measure the location of BIMs for several laboratory flows and confirm their role as barriers to front propagation.

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We present experiments on reactive front propagation in a two-dimensional (2D) vortex chain flow (both time-independent and time-periodic) and a 2D spatially disordered (time-independent) vortex-dominated flow. The flows are generated using magnetohydrodynamic forcing techniques, and the fronts are produced using the excitable, ferroin-catalyzed Belousov-Zhabotinsky chemical reaction. In both of these flows, front propagation is dominated by the presence of burning invariant manifolds (BIMs) that act as barriers, similar to invariant manifolds that dominate the transport of passive impurities. Convergence of the fronts onto these BIMs is shown experimentally for all of the flows studied. The BIMs are also shown to collapse onto the invariant manifolds for passive transport in the limit of large flow velocities. For the disordered flow, the measured BIMs are compared to those predicted using a measured velocity field and a three-dimensional set of ordinary differential equations that describe the dynamics of front propagation in advection-reaction-diffusion systems.

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This article investigates barriers to a wider utilization of a Learning Management System (LMS). The study aims to identify the reasons why some tools in the LMS are rarely used, in spite of assertions that the learning experience and students’ performance can be improved by interaction and collaboration, facilitated by the LMS. Lecturers’ perceptions about the use of LMSs over the last four years at the School of Engineering, University of Borås were investigated. Seventeen lecturers who were interviewed in 2006 were interviewed again in 2011. The lecturers’ still use the LMS primarily for distribution of documents and course administration. The results indicate that their attitudes have not changed significantly. The apparent reluctance to utilize interactive features in the LMS is analyzed, by looking at the expected impact on the lecturers’ work situation. The author argues that the main barrier to a wider utilization of LMS is the lecturers’ fear of additional demands on their time. Hence, if educational institutions want a wider utilization of LMS, some kind of incentives for lecturers are needed, in addition to support and training.