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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

Mammal and bird road mortalities on the Upington to Twee Rivieren main road in the southern Kalahari, South Africa

Bullock, KL, Malan, G, Pretorius, MD 14 January 2011 (has links)
Road ecology is becoming an increasingly important aspect of conservation biology. Carcasses lying on the road often confront visitors travelling to the Kgalagadi Transfrontier Park between Upington and the Twee Rivieren Rest Camp. This study investigated the species killed, the factors contributing to their deaths, and suggested solutions to curtail these mortalities. Twelve surveys to record mammal and bird road mortalities were conducted on the R360 main road between Upington and Twee Rivieren (261 km) from January to September 2007. One hundred and eighty four carcasses were recorded from 22 species, and the most common taxa killed were the bat-eared fox (n = 47) and spotted eagle owl (n = 10). The road mortality rate on the R360 road was very high, 5.44 mammals and 1.14 birds per 100 km. Birds were predominantly killed in summer. Notably more nocturnal mammals were killed than diurnal and ‘indistinct’ species. A mammal hotspot was identified along the 91 km of road that traversed the Gordonia duneveld. Since the nine roadside traffic warning signs erected on the R360 road had no measurable impact on road mortalities, it is recommend that three rumble strip sections with accompanying signage be erected in the hotspot to slow down vehicles and curtail mortalities.
2

Inactivation of Mycobacterium avium subspecies paratuberculosis and profiles of microbial communities during composting of livestock mortalities

Tkachuk, Victoria L. 03 1900 (has links)
This study explored the use of a biosecure, static composting structure to inactivate MAP. In Experiment #1, it was concluded that composting is unlikely to achieve temperatures necessary to inactivate MAP associated with cattle mortalities and that M. smegamatis is an unlikely surrogate for MAP. This study also used the same system to explore changes in the microbial community in mortality compost after exposure to thermophilic temperatures. As high-throughput sequencing technologies advance, it is possible to characterize microbial communities in environments with a high degree of resolution. In Experiment #2, as members of Clostridia were present at temperatures > 55°C, it appears that anaerobic conditions existed within regions of the compost. Extreme temperatures and non-homogeneous high moisture conditions resulted in spatial distribution of temperature in a biosecure, static composting system, which failed to meet conditions necessary for complete composting and pathogen reduction.
3

Inactivation of Mycobacterium avium subspecies paratuberculosis and profiles of microbial communities during composting of livestock mortalities

Tkachuk, Victoria L. 03 1900 (has links)
This study explored the use of a biosecure, static composting structure to inactivate MAP. In Experiment #1, it was concluded that composting is unlikely to achieve temperatures necessary to inactivate MAP associated with cattle mortalities and that M. smegamatis is an unlikely surrogate for MAP. This study also used the same system to explore changes in the microbial community in mortality compost after exposure to thermophilic temperatures. As high-throughput sequencing technologies advance, it is possible to characterize microbial communities in environments with a high degree of resolution. In Experiment #2, as members of Clostridia were present at temperatures > 55°C, it appears that anaerobic conditions existed within regions of the compost. Extreme temperatures and non-homogeneous high moisture conditions resulted in spatial distribution of temperature in a biosecure, static composting system, which failed to meet conditions necessary for complete composting and pathogen reduction.
4

Detekce a variabilita patogenu račího moru ve vybraných populacích raků / Detection and variation of the crayfish plague pathogen in selected crayfish populations

Mojžišová, Michaela January 2019 (has links)
Crayfish plague is an emerging disease caused by the oomycete Aphanomyces astaci, a pathogen listed among the 100 World's Worst Invasive Alien Species. It was introduced into Europe in the second half of 19th century from North America and caused collapses of European native crayfish populations. Nowadays, A. astaci is widespread in Europe and has spread also to other parts of the world, threatening all susceptible crayfish of non-North American origin. The aims of this MSc thesis were 1) to provide information about crayfish plague outbreaks from recent years, and by using microsatellite and mtDNA markers reveal A. astaci genotypes involved; 2) to test healthy-looking indigenous crayfish for potential occurrence of chronic infections by A. astaci in Czechia. Six new crayfish plague outbreaks were confirmed from 2016 to 2018, involving at least five distinct pathogen strains. My results provide first evidence of the A. astaci genotype group D causing Astacus astacus and Austropotamobius torrentium mass mortalities in Czechia. MtDNA sequencing revealed two haplotypes of the D haplogroup, indicating two independent sources of infection presumably either from ornamental crayfish or spreading from neighbouring countries. The genotype group A was recorded in two A. astacus mortalities and genotype group...
5

Health System Access to Maternal and Child Health Services in Sierra Leone

Kanu, Alhassan Fouard 01 January 2019 (has links)
The robustness and responsiveness of a country's health system predict access to a range of health services, including maternal and child health (MCH) services. The purpose of this cross-sectional study was to examine the influence of 5 health system characteristics on access to MCH services in Sierra Leone. This study was guided by Bryce, Victora, Boerma, Peters, and Black's framework for evaluating the scaleup to millennium development goals for maternal and child survival. The study was a secondary analysis of the Sierra Leone 2017 Service Availability and Readiness Assessment dataset, which comprised 100% (1, 284) of the country's health facilities. Data analysis included bivariate and multivariate logistic regressions. In the bivariate analysis, all the independent variables showed statistically significant association with access to MCH services and achieved a p-value < .001. In the multivariate analysis; however, only 3 predictors explained 38% of the variance (R� = .380, F (5, 1263) = 154.667, p <.001). The type of health provider significantly predicted access to MCH services (β =.549, p <.001), as did the availability of essential medicines (β= .255, p <.001) and the availability of basic equipment (β= .258, p <.001). According to the study findings, the availability of the right mix of health providers, essential medicines, and basic equipment significantly influenced access to MCH services, regardless of the level and type of health facility. The findings of this study might contribute to positive social change by helping the authorities of the Sierra Leone health sector to identify critical health system considerations for increased access to MCH services and improved maternal and child health outcomes.
6

Environmental Impact of livestock mortalities burial

Pratt, Dyan Lindsay 09 June 2009
The objective of this thesis was to determine the potential impact on groundwater quality as a result of the release of leachate from livestock mortality burial for three species of livestock: swine, bovine and poultry. Specific objectives were to:<p> 1.Characterize the chemical composition of leachate in livestock mortality burial pits for three species: bovine, swine and poultry; and<p> 2.Evaluate the potential environmental impact of livestock burial through groundwater transport modelling.<p> A two part program was followed to achieve these objectives. The first portion involved construction of lined burial pits complete with leachate collection systems. Poultry (1300kg), swine (5900kg) and bovine (9750kg) carcasses were each placed in separate pits and the pits covered with plastic liner material and then approximately one meter of earthen cover. The pits were sampled for leachate chemical analysis at 2 weeks, 1 month, 2 months, 4 months, 8 months, 14 months and 25 months post burial. The second portion involved using the chemical analysis results from first portion and two groundwater modeling software packages (CTRAN and PHREEQC) to characterize the leachate and evaluate the potential this material could have on groundwater resources adjacent to burial pits.<p> The results indicated that livestock mortality leachate contains, on average, after two years of decomposition, concentrations of 12,600 mg/L of ammonium-N, 34,600 mg/L alkalinity (as bicarbonate), 2,600 mg/L chloride, 3,600 mg/L sulphate, 2,300 mg/L potassium, 1,800 mg/L sodium, 1,500 mg/L phosphorus along with relative lesser amounts of iron, calcium and magnesium. Maximum values for the major ions were up to 50% higher than the average in some instances. The pH of the leachate was near neutral. In comparison to earthen manure storages and landfills, the strength of the leachate was 2-4 times higher.<p> To properly characterize the leachate chemistry, speciation of the mortality leachate was performed using PHREEQC. This speciation provided evidence of phosphate compounds precipitating from solution, as well as significant amounts of phosphoric acids (0.03 mol/L). Relatively high concentrations of ammonium sulphate also formed and due to the negative charge, allow for potentially 300 mg-N/L to transport conservatively. In comparison to naturally occurring groundwater, activities of bicarbonate, sulphates, phosphates and other minerals were many orders of magnitude higher than concentrations present in groundwater.<p> Preliminary simulations were created with two software packages, Geo-Slope CTRAN and PHREEQC to simulate transport of the leachate for three different soil conditions. The Geo-Slope model models a conservative contaminant, while the PHREEQC model involves geochemical speciation and contaminant transport including ion exchange occurring along the pathway. Transport through a low permeable soil (K=1 x 10-10 m/s) was dominated by diffusion allowing unattenuated leachate to transport a distance of approximately three meters in 50 years. The moderately permeable soil situation (K=1 x 10-9 m/s) produced a transport depth of six meters with an approximate concentration of the tracer thirty to forty percent of initial concentration in 50 years. In a highly permeable soil (K=1 x 10-8 m/s), transport reached a depth of 10 meters in 10 years with approximately forty percent of initial concentration. The PHREEQC transport model demonstrated a highly concentrated calcium and magnesium plume forming in front of the ammonium plume suggesting ion exchange and attenuation of ammonium.<p> In the occurrence of a mass mortality event, regulators in Canada have decided to employ a trench burial system. Trenches could be created using on-the-farm equipment such as backhoes to obtain approximate trench dimensions of 2 m wide and 4 m deep. To assess the impact of multiple trenches and their appropriate spacing, models were created with Geo-Slope CTRAN to evaluate the effects on trench spacing. It was determined through these models that a minimum 10 m separation distance would provide a potential contaminant plume maximum soil contact and no trench-to-trench impact.<p> To further evaluate the potential impact of livestock burial leachate, mass loading into an aquifer was evaluated for a moderately permeable soil (K=1 x 10-9 m/s) for a mass mortality event in a 10,000 head feedlot. Disposal consisted of ten 200 m trenches with a 10 m separation distance. Disposal covered 2.2 hectares and provided a mass loading of ammonium to an aquifer 10 m below of 950 kg/year after 50 years and increasing from 50 years until the peak concentration of the plume reached the aquifer. At this loading rate, nitrogen concentrations exceed drinking water standards 10-15 times.
7

Environmental Impact of livestock mortalities burial

Pratt, Dyan Lindsay 09 June 2009 (has links)
The objective of this thesis was to determine the potential impact on groundwater quality as a result of the release of leachate from livestock mortality burial for three species of livestock: swine, bovine and poultry. Specific objectives were to:<p> 1.Characterize the chemical composition of leachate in livestock mortality burial pits for three species: bovine, swine and poultry; and<p> 2.Evaluate the potential environmental impact of livestock burial through groundwater transport modelling.<p> A two part program was followed to achieve these objectives. The first portion involved construction of lined burial pits complete with leachate collection systems. Poultry (1300kg), swine (5900kg) and bovine (9750kg) carcasses were each placed in separate pits and the pits covered with plastic liner material and then approximately one meter of earthen cover. The pits were sampled for leachate chemical analysis at 2 weeks, 1 month, 2 months, 4 months, 8 months, 14 months and 25 months post burial. The second portion involved using the chemical analysis results from first portion and two groundwater modeling software packages (CTRAN and PHREEQC) to characterize the leachate and evaluate the potential this material could have on groundwater resources adjacent to burial pits.<p> The results indicated that livestock mortality leachate contains, on average, after two years of decomposition, concentrations of 12,600 mg/L of ammonium-N, 34,600 mg/L alkalinity (as bicarbonate), 2,600 mg/L chloride, 3,600 mg/L sulphate, 2,300 mg/L potassium, 1,800 mg/L sodium, 1,500 mg/L phosphorus along with relative lesser amounts of iron, calcium and magnesium. Maximum values for the major ions were up to 50% higher than the average in some instances. The pH of the leachate was near neutral. In comparison to earthen manure storages and landfills, the strength of the leachate was 2-4 times higher.<p> To properly characterize the leachate chemistry, speciation of the mortality leachate was performed using PHREEQC. This speciation provided evidence of phosphate compounds precipitating from solution, as well as significant amounts of phosphoric acids (0.03 mol/L). Relatively high concentrations of ammonium sulphate also formed and due to the negative charge, allow for potentially 300 mg-N/L to transport conservatively. In comparison to naturally occurring groundwater, activities of bicarbonate, sulphates, phosphates and other minerals were many orders of magnitude higher than concentrations present in groundwater.<p> Preliminary simulations were created with two software packages, Geo-Slope CTRAN and PHREEQC to simulate transport of the leachate for three different soil conditions. The Geo-Slope model models a conservative contaminant, while the PHREEQC model involves geochemical speciation and contaminant transport including ion exchange occurring along the pathway. Transport through a low permeable soil (K=1 x 10-10 m/s) was dominated by diffusion allowing unattenuated leachate to transport a distance of approximately three meters in 50 years. The moderately permeable soil situation (K=1 x 10-9 m/s) produced a transport depth of six meters with an approximate concentration of the tracer thirty to forty percent of initial concentration in 50 years. In a highly permeable soil (K=1 x 10-8 m/s), transport reached a depth of 10 meters in 10 years with approximately forty percent of initial concentration. The PHREEQC transport model demonstrated a highly concentrated calcium and magnesium plume forming in front of the ammonium plume suggesting ion exchange and attenuation of ammonium.<p> In the occurrence of a mass mortality event, regulators in Canada have decided to employ a trench burial system. Trenches could be created using on-the-farm equipment such as backhoes to obtain approximate trench dimensions of 2 m wide and 4 m deep. To assess the impact of multiple trenches and their appropriate spacing, models were created with Geo-Slope CTRAN to evaluate the effects on trench spacing. It was determined through these models that a minimum 10 m separation distance would provide a potential contaminant plume maximum soil contact and no trench-to-trench impact.<p> To further evaluate the potential impact of livestock burial leachate, mass loading into an aquifer was evaluated for a moderately permeable soil (K=1 x 10-9 m/s) for a mass mortality event in a 10,000 head feedlot. Disposal consisted of ten 200 m trenches with a 10 m separation distance. Disposal covered 2.2 hectares and provided a mass loading of ammonium to an aquifer 10 m below of 950 kg/year after 50 years and increasing from 50 years until the peak concentration of the plume reached the aquifer. At this loading rate, nitrogen concentrations exceed drinking water standards 10-15 times.
8

Etude démographique économique et sociale de la cité de Toulon du début du XVème siècle au premier tiers du XVIème siècle (1535)

Luccioni, Jean 14 December 2012 (has links)
La cité maritime subit le trend de la récession du XIVe siècle jusqu'à son inversion pour celui de la croissance, mutation due, à Toulon, au dynamisme de la draperie et de la construction navale. La croissance, élevée après 1517, se matérialise par la reconstruction des faubourgs. Les options commerciales des négociants, vente d'huile, de draps, de cuirs et peaux, de barques et de petites nefs sur un marché élargi, vont dégager des bénéfices considérables. Les édiles vont contrôler progressivement les maux dont souffre la cité : sa carence en céréales, les épidémies de peste et de lèpre, les menaces de flottes hostiles, la dette contractée, après emprunt, chez les marchands florentins avignonnais. Une oligarchie d'une trentaine de familles, associant notaires et marchands, a dirigé la ville. / The maritime city undergoes the recession's trend of the 15th century until its inversion toward growth, a mutation due to the dynamism of Toulon drapery and shipbuilding. The high growth after 1517 is materialized by the reconstruction of the suburbs. The commercial options of traders, selling oil, sheets, hides and skins, boats and small ships on a wider market, will generate substantial profits. The councilors will gradually control the evills of the city : its deficiencies in cereals, epidemies of plagues and leprosy, threats of hostile fleets, debt after borrowing Florentine merchants in Avignon. An oligarchy of thirty families associating notaries and merchants, led the city during the last century of the middle ages.
9

\"Aspectos da pesca e dinâmica de populações do espada, Trichiurus lepturus (Trichiuridae, Teleostei), da costa sudeste-Sul do Brasil\" / Fishery aspects and populations dynamics of the cutlassfish, Trichiurus lepturus, (Trichiuridae, Teleostei), of the Southeast-south coast of Brazil.

Magro, Marizilda 30 May 2006 (has links)
Os aspectos da pesca do espada, Trichiurus lepturus (Linnaeus, 1758) (Trichiuridae), foram descritos e analisados para as artes de pesca artesanal de linha-de-mão em Arraial do Cabo (RJ) e cerco flutuante em Porto Belo (SC), e da pesca comercial de arrasto de fundo com parelhas na costa de São Paulo. Verificaram-se tendências crescentes na produção da espécie, principalmente na pesca artesanal. Foram utilizados marcadores moleculares tipo RAPD para analisar a estrutura genético-populacional da espécie com exemplares de Belém (PA), Natal (RN), Arraial do Cabo (RJ), Guarujá (SP), Porto Belo (SC) e Rio Grande (RS), evidenciando-se uma população distinta em Belém, enquanto as demais não apresentaram estruturação definida. A dinâmica de populações foi analisada para exemplares de Arraial do Cabo, São Paulo e Porto Belo, coletados mensalmente de janeiro/2002 a julho/2003. A desova da espécie é parcelada com período reprodutivo ocorrendo do verão ao início do inverno. As fêmeas maduras migram para a plataforma encontrando-se com os machos maduros que ali permanecem, retornando à costa após a desova. O comprimento médio de primeira maturação sexual variou de 647 a 670mm (Lt) para fêmeas, e de 526 a 650mm para machos. As estimativas dos parâmetros de crescimento foram as seguintes: para fêmeas Loo de 1740 a 2010mm; k de 0,12 a 0,15/ano e t0 de -1,642 a -2,517 anos; para machos Loo de 1373 a 1580mm; k de 0,17 a 0.25/ano e t0 de -1,662 a -1,866 anos. A longevidade foi cerca de 14 anos. As taxas de mortalidade natural variaram de 0,20 a 0,29/ano. O modelo de rendimento relativo por recruta indicou que as taxas de mortalidade por pesca do espada estão próximas ou já ultrapassam os limites do rendimento máximo sustentável. / The fishery aspects of the cutlassfish, Trichiurus lepturus (Linnaeus, 1758) (Trichiuridae), were analyzed for the artisanal fishery of line and hook of Arraial do Cabo (RJ) and floating encirclement of Porto Belo (SC), and of the commercial paired bottom trawlers in the coast of São Paulo. Tendencies in increasing yields were detected, mainly in the artisanal fishery. RAPD markers techniques were employed in order to analyze the genetic-population structure of the cutlassfish from Belém (PA), Natal (RN), Arraial do Cabo (RJ), Guarujá (SP), Porto Belo (SC) and Rio Grande (RS), showing a different population in Belém, while the others did not show a clearly defined structure. The population dynamics were analyzed for fishes of Arraial do Cabo, São Paulo and Porto Belo, collected monthly of January/2002 to July/2003. The cutlassfish spawning is parceled with reproductive period from the summer to the beginning of the winter. Ripe females migrate offshore to mate with ripe males that stay there, returning to the coast just after spawning. The length of first sexual maturity varied from 647 to 670mm (Lt) for females, and 526 to 650mm for males. The estimates of growth parameters were: for females Loo from 1740 to 2010mm; k from 0,12 to 0,15/year and t0 from -1,642 to -2,517 years, and for males Loo from 1373 to 1580mm; k from 0,171 0.255/year and t0 from -1,662 to -1,866 years. The longevity was about 14 years. The natural mortality rate varied from 0,20 to 0,29/year. The relative yield per recruit model showed that fishing mortality rates of the cutlassfish are close or just exceeding the limits of the maximum sustainable yield.
10

\"Aspectos da pesca e dinâmica de populações do espada, Trichiurus lepturus (Trichiuridae, Teleostei), da costa sudeste-Sul do Brasil\" / Fishery aspects and populations dynamics of the cutlassfish, Trichiurus lepturus, (Trichiuridae, Teleostei), of the Southeast-south coast of Brazil.

Marizilda Magro 30 May 2006 (has links)
Os aspectos da pesca do espada, Trichiurus lepturus (Linnaeus, 1758) (Trichiuridae), foram descritos e analisados para as artes de pesca artesanal de linha-de-mão em Arraial do Cabo (RJ) e cerco flutuante em Porto Belo (SC), e da pesca comercial de arrasto de fundo com parelhas na costa de São Paulo. Verificaram-se tendências crescentes na produção da espécie, principalmente na pesca artesanal. Foram utilizados marcadores moleculares tipo RAPD para analisar a estrutura genético-populacional da espécie com exemplares de Belém (PA), Natal (RN), Arraial do Cabo (RJ), Guarujá (SP), Porto Belo (SC) e Rio Grande (RS), evidenciando-se uma população distinta em Belém, enquanto as demais não apresentaram estruturação definida. A dinâmica de populações foi analisada para exemplares de Arraial do Cabo, São Paulo e Porto Belo, coletados mensalmente de janeiro/2002 a julho/2003. A desova da espécie é parcelada com período reprodutivo ocorrendo do verão ao início do inverno. As fêmeas maduras migram para a plataforma encontrando-se com os machos maduros que ali permanecem, retornando à costa após a desova. O comprimento médio de primeira maturação sexual variou de 647 a 670mm (Lt) para fêmeas, e de 526 a 650mm para machos. As estimativas dos parâmetros de crescimento foram as seguintes: para fêmeas Loo de 1740 a 2010mm; k de 0,12 a 0,15/ano e t0 de -1,642 a -2,517 anos; para machos Loo de 1373 a 1580mm; k de 0,17 a 0.25/ano e t0 de -1,662 a -1,866 anos. A longevidade foi cerca de 14 anos. As taxas de mortalidade natural variaram de 0,20 a 0,29/ano. O modelo de rendimento relativo por recruta indicou que as taxas de mortalidade por pesca do espada estão próximas ou já ultrapassam os limites do rendimento máximo sustentável. / The fishery aspects of the cutlassfish, Trichiurus lepturus (Linnaeus, 1758) (Trichiuridae), were analyzed for the artisanal fishery of line and hook of Arraial do Cabo (RJ) and floating encirclement of Porto Belo (SC), and of the commercial paired bottom trawlers in the coast of São Paulo. Tendencies in increasing yields were detected, mainly in the artisanal fishery. RAPD markers techniques were employed in order to analyze the genetic-population structure of the cutlassfish from Belém (PA), Natal (RN), Arraial do Cabo (RJ), Guarujá (SP), Porto Belo (SC) and Rio Grande (RS), showing a different population in Belém, while the others did not show a clearly defined structure. The population dynamics were analyzed for fishes of Arraial do Cabo, São Paulo and Porto Belo, collected monthly of January/2002 to July/2003. The cutlassfish spawning is parceled with reproductive period from the summer to the beginning of the winter. Ripe females migrate offshore to mate with ripe males that stay there, returning to the coast just after spawning. The length of first sexual maturity varied from 647 to 670mm (Lt) for females, and 526 to 650mm for males. The estimates of growth parameters were: for females Loo from 1740 to 2010mm; k from 0,12 to 0,15/year and t0 from -1,642 to -2,517 years, and for males Loo from 1373 to 1580mm; k from 0,171 0.255/year and t0 from -1,662 to -1,866 years. The longevity was about 14 years. The natural mortality rate varied from 0,20 to 0,29/year. The relative yield per recruit model showed that fishing mortality rates of the cutlassfish are close or just exceeding the limits of the maximum sustainable yield.

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