Thesis (M.Eng.). / Written for the Dept. of Civil Engineering and Applied Mechanics. Title from title page of PDF (viewed 2008/07/29). Includes bibliographical references.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2001. / Abstract inserted. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Nitrous oxide (N2O) is a potent greenhouse gas mainly emitted from agriculture. In the biological process of denitrification, intermediates of the nitrogen cycle are reduced under oxygen limiting conditions thereby releasing N2O. Denitrification is influenced by various environmental factors and both bacteria and fungi are capable of denitrification. The ultimate aim of this thesis was to determine the significance of fungal and bacterial denitrification in arable soil and to investigate influences of soil pH and physical disturbance on potential denitrification rates and denitrifying communities. Long-term pH plots combined with a disturbance gradient have been utilised to investigate fungal and bacterial denitrification distinguished by application of selective inhibitors. Highest N2O production was measured from slightly acidic soil and soil with reduced disturbance. Fungi and bacteria contributed to N2O production with bacterial denitrification as dominant source. Fungal denitrification remained unaffected by soil pH and disturbance whereas bacterial denitrification was influenced by these factors. Bacterial denitrification was positively correlated with concentrations of fatty acids which suggested that these fatty acids were common to bacteria involved in N2O production in the soils investigated here. Bacterial community structure changed with soil pH and disturbance whereas fungal community structure was only influenced by disturbance. Bacterial denitrifier communities (nitrite reductases nirK and nirS) changed over the pH gradient but only the nirK community was affected by disturbance. This indicated that groups of bacterial denitrifiers follow different ecological strategies. Gene abundance of nirK and nirS was also correlated to concentrations of the fatty acids associated with denitrifying bacteria in the soils investigated here. In conclusion, fungal denitrification was significant in arable soil but remained unchanged by soil pH and disturbance. Therefore, fungal denitrification is important in agricultural ecosystems and should be considered when developing mitigation strategies for N2O production especially under conditions favourable for fungal denitrification.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: Dr. Christian Baron. Includes bibliographical references (leaves 94-101).

The principal Water target of the Millennium Development Goals (MDG) is to Ensure environmental sustainability by halving the proportion of people without access to safe water by 2015. Although great strides have been made in meeting this challenge in terms of provision of services since the year 2000, the safety of many these water supplies remains unknown. One of the biggest challenges therefore facing water development professionals is how to ensure sufficient levels of both quantity and guality of safe water. One of the principal mechanisms for monitoring the progress towards attaining the MDG goals for access to safe water is the UNICEF/WHO Joint Monitoring Programme (JMP). However, the JMP acknowledges that one of its current weaknesses is in assessing safety related to different technology types. In acknowledgement of these weaknesses and of the weakness of reliance on "end product testing" as a means of assuring microbiological safety, the thesis proposes improved methods of assessment and management of microbiological water safety based on a "risk" paradigm. Coinciding with proposed new risk based methods of assessing water safety outlined in the 3d edition of the World Health Organization Guidelines for Drinking Water Quality (2004), the thesis researches the risk to three well technology types in Mozambique. Principal pathways to microbiological contamination of shallow groundwater were assessed which included both the conventional aquifer pathways and preferential or localised pathways. The research adopted an experimental design that uses a mix of qualitative and quantitative data collection techniques. Data were collected over 12 months in 25 well sites in Lichinga, Mozambique. Findings from the research demonstrated that risk assessment and management are effective tools in understanding the level of safety associated with the well technologies under study. The research indicated firstly that risk assessment aids the identification of specific risk variables (of which animal faeces is a predominant risk), secondly that the use of alternative indicator organisms (e.g. enterococci) may improve risk understanding, thirdly that there is a strong statistical correlation between use of surrogates (e. g. turbidity) and microbes and fourthly that Water Safety Plans are an appropriate method of risk management. Furthermore, the research supports the JMP definitions of improved water sources, which suggest that upgraded wells are not an improved source due to their high vulnerability to contamination through localised pathways. The recommendations from the thesis include; non-inclusion of upgraded wells in the JMP in Mozambique, greater use of enterococci and turbidity as surrogate indicators of faecal pollution, the need for the development of rapid risk assessment and management techniques for rural areas in developing countries and the inclusion of localised pathways as a principal route of assessment. Potential areas of further research include field-based studies of assessment of faecal sources of Enterococci bacteria, and rapid methods for the development of model Water Safety Plans.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-04T17:56:43Z No. of bitstreams: 1 camilafariacarrada.pdf: 1705454 bytes, checksum: dbf21cbcbbd9768b8a87c74182b60328 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-07T03:23:56Z (GMT) No. of bitstreams: 1 camilafariacarrada.pdf: 1705454 bytes, checksum: dbf21cbcbbd9768b8a87c74182b60328 (MD5) / Made available in DSpace on 2015-12-07T03:23:56Z (GMT). No. of bitstreams: 1 camilafariacarrada.pdf: 1705454 bytes, checksum: dbf21cbcbbd9768b8a87c74182b60328 (MD5) Previous issue date: 2015-04-24 / É de fundamental importância investigar a colonização de periodontopatógenos e seu papel na etiologia da doença periodontal de crianças e adolescentes com síndrome de Down, os quais apresentam alta prevalência da doença. O objetivo deste estudo foi avaliar qualitativa e quantitativamente a presença na saliva de bactérias periodontopatogênicas em crianças e adolescentes com e sem síndrome de Down. Este estudo transversal incluiu uma amostra de trinta crianças e adolescentes com síndrome de Down (grupo SD), com idade entre 3-12 anos, e trinta controles sem a síndrome (grupo ND), com idades entre 4-12 anos. Exame clínico foi realizado para determinar o índice de sangramento à sondagem e o índice de placa em dentes índice. Amostras de saliva não estimuladas foram coletadas de todos os participantes. A técnica de hibridização in situ fluorescente (FISH) identificou a presença e as densidades de oito bactérias periodontopatogênicas na saliva. O teste qui-quadrado foi utilizado para analisar as variáveis categóricas e o teste U de Mann-Whitney foi utilizado para as variáveis numéricas. Adotou-se um nível de significância de 5%. Os registros clínicos mostraram frequência mais alta de crianças e adolescentes com sangramento à sondagem no grupo SD (P = 0,037); nenhuma diferença foi encontrada em relação ao índice de placa entre os grupos (P = 0,516). Crianças e adolescentes com síndrome de Down apresentaram densidades maiores de Campylobacter rectus (P = 0,013), Porphyromonas gingivalis (P = 0,025), Treponema denticola (P = 0,026), Fusobacterium nucleatum (P = 0,013), Prevotella intermedia (P = 0,001) e Prevotella nigrescens (P = 0,008). Nenhuma diferença significativa foi encontrada nas densidades de Aggregatibacter actinomycetemcomitans (P = 0,057) e Tanerella forsythia (P = 0,584). No grupo SD, as densidades das bactérias do complexo laranja foram significativamente maiores nas faixas etárias de 3 a 7 anos para F. nucleatum, P. intermedia e P. nigrescens, e de 8 a 12 anos para C. rectus. Os resultados confirmam que crianças e adolescentes com síndrome de Down apresentam maior suscetibilidade à doença periodontal e maior prevalência e densidade de patógenos periodontais importantes para o estabelecimento e agravamento da doença periodontal. / It is of particular importance to investigate the colonization of periodontal pathogens and their role in the etiology of periodontal disease in children and adolescents with Down syndrome, who have a high prevalence of periodontal disease. The aim of this study was to assess qualitative and quantitatively the presence of periodontopathogenic bacteria in saliva in a group of Down and non-Down syndrome children and adolescents. This cross-sectional study included a sample of 30 Down syndrome children and adolescents (group DS), aged 3-12 years, and 30 non-Down syndrome children and adolescents (group ND) aged 4-12 years. Dental examinations were performed to determine the bleeding on probing index and plaque index in index teeth. Unstimulated whole saliva samples were collected from all participants. The fluorescence in situ hybridization (FISH) technique identified the presence and density of eight periodontopathogenic bacteria in saliva. The chisquare test was used to analyze the categorical variables and the Mann-Whitney U test was used for the continuous variables. The significance level was set at 5%. Clinical records showed a higher frequency of children and adolescents with bleeding on probing in DS group (P = 0.037); no significant difference was found in relation to plaque index between the groups (P = 0.516). Down syndrome children showed higher salivary density of Campylobacter rectus (P = 0.013), Porphyromonas gingivalis (P = 0.025), Treponema denticola (P = 0.026), Fusobacterium nucleatum (P = 0.013), Prevotella intermedia (P = 0.001) and Prevotella nigrescens (P = 0.008). No significant difference was found in salivary density of Aggregatibacter actinomycetemcomitans (P = 0.057) and Tanerella forsythia (P = 0.584). In DS group, the densities of bacteria of orange complex were higher in the age groups 3-7 years for F. nucleatum, P. intermedia and P. nigrescens, as well as in age groups 8-12 years for C. rectus. The results confirm that Down syndrome children and adolescents have an increased susceptibility to periodontal disease and higher prevalence and density of important periodontal pathogens for the onset and worsening of the periodontal disease.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-03-29T13:42:08Z No. of bitstreams: 1 flaviaalmeidaribeiroscalioni.pdf: 2339144 bytes, checksum: fc488fda19373aa72588dc3ad1e242c3 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T02:47:32Z (GMT) No. of bitstreams: 1 flaviaalmeidaribeiroscalioni.pdf: 2339144 bytes, checksum: fc488fda19373aa72588dc3ad1e242c3 (MD5) / Made available in DSpace on 2016-04-24T02:47:32Z (GMT). No. of bitstreams: 1 flaviaalmeidaribeiroscalioni.pdf: 2339144 bytes, checksum: fc488fda19373aa72588dc3ad1e242c3 (MD5) Previous issue date: 2013-04-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Crianças com síndrome de Down (SD) apresentam uma baixa prevalência de cárie dentária. Embora os Streptococcus mutans e Streptococcus sobrinus estejam associados com a cárie dentária em humanos, o seu papel na etiologia da doença em crianças com SD ainda não está completamente esclarecido. Desta forma, este estudo transversal teve como objetivo avaliar a experiência de cárie dentária e a contagem de S. mutans, S. sobrinus e estreptococos presentes na saliva de crianças com SD (grupo SD) em comparação com crianças não sindrômicas (grupo ND). A amostra incluiu trinta crianças com SD (com idade entre três e 12 anos) e trinta crianças (com idade entre quatro e 12 anos) sem a síndrome, pareadas por idade e sexo. O exame da condição dentária foi realizado para determinar o número de dentes decíduos cariados, com extração indicada e obturados (índice ceo-d) e o número de dentes permanentes cariados, perdidos e obturados (índice CPO-D), de acordo com os critérios de diagnóstico de cárie dentária da OMS. Amostras de saliva total não estimulada foram coletadas de todas as crianças. A técnica da hibridização in situ fluorescente (FISH) identificou a presença e o número de bactérias cariogênicas na saliva. O teste qui-quadrado foi usado para a análise das variáveis categóricas e o teste t de Student foi usado para a análise das variáveis contínuas. Adotou-se o nível de significância de 5% (p < 0,05). As crianças do grupo SD apresentaram significativamente uma experiência de cárie dentária mais baixa (p < 0,001) e mais baixa contagem de S. mutans na saliva (p < 0,001), em comparação com as crianças do grupo ND. Não se observou nenhuma diferença estatisticamente significativa na contagem de S. sobrinus e estreptococos presentes na saliva entre os dois grupos (p = 0,09 e p = 0,21, respectivamente). As contagens de S. mutans e S. sobrinus presentes na saliva, determinadas pela técnica de FISH, não se associaram a mais baixa experiência de cárie dentária observada entre as crianças com síndrome de Down. / Down syndrome (DS) children are known to present a low dental caries prevalence. Although Streptococcus mutans and Streptococcus sobrinus are associated with dental caries in humans, their role in the etiology of dental caries in DS children is not entirely clear. Therefore this cross-sectional study aimed to assess the dental caries experience as well as the salivary counts of S. mutans, S. sobrinus and streptococci in DS children (group SD) in comparison with non-Down syndrome children (group ND). The sample included 30 DS children (aged 3-12 years) and 30 age and sex-matched ND children (aged 4-12 years). Dental examinations were performed to determine the numbers of decayed, missing and filled teeth in primary (dmf-t index) and permanent (DMF-T index) dentition according to the WHO dental caries diagnostic criteria. Unstimulated whole saliva samples were collected from all children. The fluorescence in situ hybridization (FISH) technique identified the presence and numbers of the cariogenic bacteria in saliva. The chi-square test was used to analyze the categorical variables and the Student’s t-test was used for the continuous variables. The significance level was set at 5% (p < 0.05). Children of DS group showed significantly lower dental caries experience (p < 0.001) and salivary counts of S. mutans (p < 0.001) compared to children of ND group. No significant difference was found in the salivary counts of S. sobrinus and streptococci between the two groups (p = 0.09 and p = 0.21, respectively). The salivary counts of S. mutans and S. sobrinus determined by the FISH technique were not associated with the lower caries experience observed in Down syndrome children.