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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Soil Microbial Community Dynamics In Florida Scrub Ecosystem

Albarracin, Maria 01 January 2005 (has links)
Pyrogenic ecosystems are maintained by fires which vary in frequency, seasonality, and intensity. Florida oak-saw palmetto scrub ecosystem is characterized by fires occurring at intervals of 10-20 years. Diverse factors as private land acquisition and development has created a patchy distribution of scrub ecosystems and also interrupted the natural fire cycle. The effects of fire over plant regeneration and fauna habitat utilization of the scrub have been well characterized in previous research. In the present paper the objective is to characterize the short- and long-term fire effects on the soil microbial community. Fire effects were studied in a chronosequence, comprising a recently burned scrub during a winter-prescribed fire to scrub where fire did not occur for 40 years. The number of culturable cells was reduced by two orders of magnitude by indirect fire effects and environmental factors, principally hydric stress. However, the duration of fire effects was very short since the microbial community returned to pre-fire numbers and activity by day 47 after fire. Microbial community activity was distinctively related to inoculum density in the soil and litter samples. Soil and litter microbial communities showed differences in metabolic activity. There was no difference in substrate utilization pattern, but there was significant seasonal variation related to the decrease in water content during the month of May. Substrate utilization by litter microbial communities was higher during the month of January compared to soil microbial communities and this relationship was inversed during the month of May probably associated to the more stringent conditions, low water availability, on the litter layer. Seasonal effects outweighed fire effects in this study as this environmental constraint determined the microbial community structure and activity.
2

What Explains Variability in Blood Pressure Readings? Multilevel Analysis of Data from 8,731 Older Adults in 20 Ontario Communities

O'Rielly, Susan 12 October 2011 (has links)
Title: What explains variability in blood pressure readings? Multilevel analysis of data from 8,731 older adults in 20 Ontario Communities Objectives: Despite universal healthcare and drug coverage for adults aged 65 and over in Ontario, hypertension, a treatable condition, remains uncontrolled among many older adults. Moreover, there are geographic disparities in blood pressure and hypertension within and across Canadian provinces and territories. Using baseline data collected on 8,731 older adults participating in the Cardiovascular Health Awareness Program (CHAP) in 20 randomly selected Ontario communities, we investigated associations between systolic blood pressure (SBP) and individual- and community-level characteristics, controlling for self-reported use of blood pressure medications. Method: Older adults were recruited via invitation by local family physicians, public advertising and word of mouth to attend community pharmacy sessions. During the sessions, trained older adult volunteers assisted participants to complete a cardiovascular disease risk factor questionnaire and blood pressure assessments using an automated blood pressure measuring device. The Postal Code Conversion File Plus was used to confirm residence within one of the 20 study communities. A multilevel linear regression analysis with participants nested within communities was used to determine which individual- and/or community-level characteristics were associated with measured systolic blood pressure level controlling for self-reported use of blood pressure medication. Results: 4,706 participants (53.9%) reported the use of blood pressure medication. Mean systolic blood pressure (SBP) levels varied among the 20 communities from 128.1 mmHg to 134.7 mmHg for participants not using blood pressure medication and from 131.9 mmHg to 139.0 mmHg for participants using blood pressure medication. The intraclass correlation coefficients were very small: less than 0.2% of the total variance was between communities. Among participants not using blood pressure medication, SBP was associated with the following individual- level characteristics: age, sex, body mass index , smoking, physical activity, stress, fruit/vegetable intake, and alcohol consumption and the following community-level characteristics: community size, community growth and the Rurality Index. Among participants using blood pressure medication, SBP was associated with the following individual-level characteristics: age, sex, body mass index, diabetes, fruit/vegetable intake, alcohol intake and one community-level characteristic: community size. The significance and magnitude of these associations were modified by the use of blood pressure medication. Conclusion: The majority of the variability in blood pressure occurs at the individual-level. There are specific individual- and community-level factors that explain variability in blood pressure readings among communities. These results can be used to inform health promotion strategies to decrease mean levels of blood pressure among older adults.
3

What Explains Variability in Blood Pressure Readings? Multilevel Analysis of Data from 8,731 Older Adults in 20 Ontario Communities

O'Rielly, Susan 12 October 2011 (has links)
Title: What explains variability in blood pressure readings? Multilevel analysis of data from 8,731 older adults in 20 Ontario Communities Objectives: Despite universal healthcare and drug coverage for adults aged 65 and over in Ontario, hypertension, a treatable condition, remains uncontrolled among many older adults. Moreover, there are geographic disparities in blood pressure and hypertension within and across Canadian provinces and territories. Using baseline data collected on 8,731 older adults participating in the Cardiovascular Health Awareness Program (CHAP) in 20 randomly selected Ontario communities, we investigated associations between systolic blood pressure (SBP) and individual- and community-level characteristics, controlling for self-reported use of blood pressure medications. Method: Older adults were recruited via invitation by local family physicians, public advertising and word of mouth to attend community pharmacy sessions. During the sessions, trained older adult volunteers assisted participants to complete a cardiovascular disease risk factor questionnaire and blood pressure assessments using an automated blood pressure measuring device. The Postal Code Conversion File Plus was used to confirm residence within one of the 20 study communities. A multilevel linear regression analysis with participants nested within communities was used to determine which individual- and/or community-level characteristics were associated with measured systolic blood pressure level controlling for self-reported use of blood pressure medication. Results: 4,706 participants (53.9%) reported the use of blood pressure medication. Mean systolic blood pressure (SBP) levels varied among the 20 communities from 128.1 mmHg to 134.7 mmHg for participants not using blood pressure medication and from 131.9 mmHg to 139.0 mmHg for participants using blood pressure medication. The intraclass correlation coefficients were very small: less than 0.2% of the total variance was between communities. Among participants not using blood pressure medication, SBP was associated with the following individual- level characteristics: age, sex, body mass index , smoking, physical activity, stress, fruit/vegetable intake, and alcohol consumption and the following community-level characteristics: community size, community growth and the Rurality Index. Among participants using blood pressure medication, SBP was associated with the following individual-level characteristics: age, sex, body mass index, diabetes, fruit/vegetable intake, alcohol intake and one community-level characteristic: community size. The significance and magnitude of these associations were modified by the use of blood pressure medication. Conclusion: The majority of the variability in blood pressure occurs at the individual-level. There are specific individual- and community-level factors that explain variability in blood pressure readings among communities. These results can be used to inform health promotion strategies to decrease mean levels of blood pressure among older adults.
4

Assessment of the Potential Functional Diversity of the Bacterial Community in a Biofilter

Grove, Jason Andrew January 2006 (has links)
A biofilter removes biodegradable contaminants from air by passing it through a biologically-active packed bed. The microorganism community is of fundamental interest but has been the focus of few studies. This work is an investigation of the bacterial community based on the potential functional diversity of the community. <br /><br /> A number of experiments were performed in laboratory-scale biofilters using ethanol as a model contaminant. All biofilters were able to remove the ethanol with elimination capacities in the range 80 to 200gVOCm<sup>-3</sup>h<sup>-1</sup>; these values are comparable with published literature. Natural organic media (peat or compost) was used as packing. <br /><br /> The potential functional diversity of the community was assessed by Community-Level Physiological Profiling (CLPP) using sole-Carbon Source Utilisation Profile (CSUP). Community samples were used to inoculate Biolog EcoPlates<sup>TM</sup>: microplates containing a selection of 31 different carbon-substrates and an indicator dye responding to bacterial growth. This technique was found to be sensitive to changes in the community structure over time and location. <br /><br /> Results showed that the community in samples taken close together (over a scale of a few centimetres) are similar and that relatively small media samples (0. 5 to 1 g) provide reproducible information. A study of a single biofilter indicated stratification of the community occurring with the community near the inlet diverging from that near the middle and outlet of the unit; this is attributed to the ethanol being degraded in the upper part of the column and the lower part of the column not being subjected to ethanol loading. In a study of two units at a higher loading rate, stratification was not observed over a period of weeks; it is suggested that the stratification may develop over this timescale as a result of the presence or absence of the Volatile Organic Compound (VOC) and not due to differences in concentration. <br /><br /> An acclimation period of 7 to 10 days was observed before near-complete removal of ethanol was attained. Monitoring of the community suggested a subsequent shift in diversity. It is suggested that the initial acclimation period is due to biofilm formation and the subsequent shift in community diversity is due to re-organisation of the community as species specialise. In a portion of the biofilter with minimal ethanol exposure, a sudden shift in community is observed after a period of some weeks. This may reflect changes as a result of starvation and indicates that periods of shut-down (when the biofilter is not loaded) may affect the community. <br /><br /> Two studies of biofilters operating in parallel were carried out. The first provided evidence of a divergence in the communities over a period of two weeks. In the second, communities in the two units underwent changes over time but observations from both units at any one time were similar. This demonstrates that biofilters set-up and operated in a similar manner may maintain similar communities but that this is not necessarily the case. This has implications for the reproducibility of laboratory experiments and for the variation of community structure with horizontal position in industrial units.
5

Assessment of the Potential Functional Diversity of the Bacterial Community in a Biofilter

Grove, Jason Andrew January 2006 (has links)
A biofilter removes biodegradable contaminants from air by passing it through a biologically-active packed bed. The microorganism community is of fundamental interest but has been the focus of few studies. This work is an investigation of the bacterial community based on the potential functional diversity of the community. <br /><br /> A number of experiments were performed in laboratory-scale biofilters using ethanol as a model contaminant. All biofilters were able to remove the ethanol with elimination capacities in the range 80 to 200gVOCm<sup>-3</sup>h<sup>-1</sup>; these values are comparable with published literature. Natural organic media (peat or compost) was used as packing. <br /><br /> The potential functional diversity of the community was assessed by Community-Level Physiological Profiling (CLPP) using sole-Carbon Source Utilisation Profile (CSUP). Community samples were used to inoculate Biolog EcoPlates<sup>TM</sup>: microplates containing a selection of 31 different carbon-substrates and an indicator dye responding to bacterial growth. This technique was found to be sensitive to changes in the community structure over time and location. <br /><br /> Results showed that the community in samples taken close together (over a scale of a few centimetres) are similar and that relatively small media samples (0. 5 to 1 g) provide reproducible information. A study of a single biofilter indicated stratification of the community occurring with the community near the inlet diverging from that near the middle and outlet of the unit; this is attributed to the ethanol being degraded in the upper part of the column and the lower part of the column not being subjected to ethanol loading. In a study of two units at a higher loading rate, stratification was not observed over a period of weeks; it is suggested that the stratification may develop over this timescale as a result of the presence or absence of the Volatile Organic Compound (VOC) and not due to differences in concentration. <br /><br /> An acclimation period of 7 to 10 days was observed before near-complete removal of ethanol was attained. Monitoring of the community suggested a subsequent shift in diversity. It is suggested that the initial acclimation period is due to biofilm formation and the subsequent shift in community diversity is due to re-organisation of the community as species specialise. In a portion of the biofilter with minimal ethanol exposure, a sudden shift in community is observed after a period of some weeks. This may reflect changes as a result of starvation and indicates that periods of shut-down (when the biofilter is not loaded) may affect the community. <br /><br /> Two studies of biofilters operating in parallel were carried out. The first provided evidence of a divergence in the communities over a period of two weeks. In the second, communities in the two units underwent changes over time but observations from both units at any one time were similar. This demonstrates that biofilters set-up and operated in a similar manner may maintain similar communities but that this is not necessarily the case. This has implications for the reproducibility of laboratory experiments and for the variation of community structure with horizontal position in industrial units.
6

Community level interventions in child and youth care practice

Derksen, Teri 02 December 2011 (has links)
The purpose of this qualitative study is to describe how child and youth care practitioners experience their engagement in community level interventions. Five child and youth care practitioners, who identified themselves as engaging in community level interventions in their work, were interviewed and data were analysed using a combined narrative and thematic approach. Eight themes emerged from the data that describe participants’ experience with community, community change and community level interventions. Results show how community level interventions have a tendency to target the micro, meso and occasionally exo, rather than macro, levels of communities. Thus, multi-level interventions are recommended as a way to shift child and youth care practice from an emphasis on interventions with individuals, towards greater emphasis on interventions that are aimed at the multiple levels of the child and youth’s ecological system. The study identifies implications for post-secondary curriculum, professional practice, agency mandates and job descriptions. / Graduate
7

What Explains Variability in Blood Pressure Readings? Multilevel Analysis of Data from 8,731 Older Adults in 20 Ontario Communities

O'Rielly, Susan 12 October 2011 (has links)
Title: What explains variability in blood pressure readings? Multilevel analysis of data from 8,731 older adults in 20 Ontario Communities Objectives: Despite universal healthcare and drug coverage for adults aged 65 and over in Ontario, hypertension, a treatable condition, remains uncontrolled among many older adults. Moreover, there are geographic disparities in blood pressure and hypertension within and across Canadian provinces and territories. Using baseline data collected on 8,731 older adults participating in the Cardiovascular Health Awareness Program (CHAP) in 20 randomly selected Ontario communities, we investigated associations between systolic blood pressure (SBP) and individual- and community-level characteristics, controlling for self-reported use of blood pressure medications. Method: Older adults were recruited via invitation by local family physicians, public advertising and word of mouth to attend community pharmacy sessions. During the sessions, trained older adult volunteers assisted participants to complete a cardiovascular disease risk factor questionnaire and blood pressure assessments using an automated blood pressure measuring device. The Postal Code Conversion File Plus was used to confirm residence within one of the 20 study communities. A multilevel linear regression analysis with participants nested within communities was used to determine which individual- and/or community-level characteristics were associated with measured systolic blood pressure level controlling for self-reported use of blood pressure medication. Results: 4,706 participants (53.9%) reported the use of blood pressure medication. Mean systolic blood pressure (SBP) levels varied among the 20 communities from 128.1 mmHg to 134.7 mmHg for participants not using blood pressure medication and from 131.9 mmHg to 139.0 mmHg for participants using blood pressure medication. The intraclass correlation coefficients were very small: less than 0.2% of the total variance was between communities. Among participants not using blood pressure medication, SBP was associated with the following individual- level characteristics: age, sex, body mass index , smoking, physical activity, stress, fruit/vegetable intake, and alcohol consumption and the following community-level characteristics: community size, community growth and the Rurality Index. Among participants using blood pressure medication, SBP was associated with the following individual-level characteristics: age, sex, body mass index, diabetes, fruit/vegetable intake, alcohol intake and one community-level characteristic: community size. The significance and magnitude of these associations were modified by the use of blood pressure medication. Conclusion: The majority of the variability in blood pressure occurs at the individual-level. There are specific individual- and community-level factors that explain variability in blood pressure readings among communities. These results can be used to inform health promotion strategies to decrease mean levels of blood pressure among older adults.
8

Temperature effects on Biolog Community Level Physiological Profiles /

D'Entremont, Hélène. January 1900 (has links) (PDF)
Thesis (M.Sc.)--Acadia University, 2001. / Includes bibliographical references (leaves 62-64). Also available on the Internet via the World Wide Web.
9

Youth violence perpetration : a systematic review of community-level protective factors and community resilience

Petersen, Cindy January 2015 (has links)
Magister Psychologiae - MPsych / This study aimed to (1) establish the conceptualization of youth violence perpetration within the literature; (2) explore identified community-level protective factors, (3) establish whether the interaction between community-level risk and protective factors are discussed, and (4) establish whether community-level protective factors are conceptualised within community resilience framework within the literature on youth violence. The research design of this study is a systematic review of literature focused on youth violence perpetration, community-level protective factors against perpetration of violence by youth, as well as community resilience. English-medium research literature published between Jan 1994 and Jan 2014 was reviewed. Databases that were searched are: Academic Search Premier, PsycArticles, MEDLINE, JSTOR, SocIndex, and SageOnline. Data extraction was done by two reviewers at three stages of review (abstract reading, title reading, and full-text reading), using three instruments for quality assessment across the three stages. Fifteen articles were deemed acceptable after review at the end of the three stages, achieving a threshold score of 50% or more, and these articles were used in the findings of this review. These primary studies were collated, systematically assessed, synthesised, and interpreted. Findings of this review indicate that youth violence perpetration is conceptualised within the research as various forms of violence committed by young people. The literature has suggested that youth violence perpetration may be as a result of a lack of social infrastructure and opportunities within impoverished communities. For this reason the provision of community resources, economic opportunity, educational and mentoring programmes, and subsequently the development of prosocial involvement/ interaction was suggested as strategies for intervention at a community level. Major findings of the study as well as the implications for practice and further research are discussed.
10

What Explains Variability in Blood Pressure Readings? Multilevel Analysis of Data from 8,731 Older Adults in 20 Ontario Communities

O'Rielly, Susan January 2011 (has links)
Title: What explains variability in blood pressure readings? Multilevel analysis of data from 8,731 older adults in 20 Ontario Communities Objectives: Despite universal healthcare and drug coverage for adults aged 65 and over in Ontario, hypertension, a treatable condition, remains uncontrolled among many older adults. Moreover, there are geographic disparities in blood pressure and hypertension within and across Canadian provinces and territories. Using baseline data collected on 8,731 older adults participating in the Cardiovascular Health Awareness Program (CHAP) in 20 randomly selected Ontario communities, we investigated associations between systolic blood pressure (SBP) and individual- and community-level characteristics, controlling for self-reported use of blood pressure medications. Method: Older adults were recruited via invitation by local family physicians, public advertising and word of mouth to attend community pharmacy sessions. During the sessions, trained older adult volunteers assisted participants to complete a cardiovascular disease risk factor questionnaire and blood pressure assessments using an automated blood pressure measuring device. The Postal Code Conversion File Plus was used to confirm residence within one of the 20 study communities. A multilevel linear regression analysis with participants nested within communities was used to determine which individual- and/or community-level characteristics were associated with measured systolic blood pressure level controlling for self-reported use of blood pressure medication. Results: 4,706 participants (53.9%) reported the use of blood pressure medication. Mean systolic blood pressure (SBP) levels varied among the 20 communities from 128.1 mmHg to 134.7 mmHg for participants not using blood pressure medication and from 131.9 mmHg to 139.0 mmHg for participants using blood pressure medication. The intraclass correlation coefficients were very small: less than 0.2% of the total variance was between communities. Among participants not using blood pressure medication, SBP was associated with the following individual- level characteristics: age, sex, body mass index , smoking, physical activity, stress, fruit/vegetable intake, and alcohol consumption and the following community-level characteristics: community size, community growth and the Rurality Index. Among participants using blood pressure medication, SBP was associated with the following individual-level characteristics: age, sex, body mass index, diabetes, fruit/vegetable intake, alcohol intake and one community-level characteristic: community size. The significance and magnitude of these associations were modified by the use of blood pressure medication. Conclusion: The majority of the variability in blood pressure occurs at the individual-level. There are specific individual- and community-level factors that explain variability in blood pressure readings among communities. These results can be used to inform health promotion strategies to decrease mean levels of blood pressure among older adults.

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