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1
Jones, Robin C. "Modeling to Improve Vegetation-Based Wetland Biological Assessment". DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/2082.
Testo completoAbstract (sommario):
To meet the requirements of the Clean Water Act (1972), natural resource managers need to be able to detect biological degradation in wetland ecosystems. Biological indices are commonly used by managers to assess wetland biological condition. The accuracy and precision of wetland condition assessments are directly related to the performance of these indices, and biological index performance is thought to be related to how well an index controls for the effects of environmental attributes on biological assemblages. Many plant-based biological indices control for environmental and biological variation through the use of classification schemes that are based on geographic location and dominant vegetation type. However, the use of classification schemes tends to produce indices with limited applicability and may not adequately control for natural variation. The goal of my research was to use modeling techniques, as an alternative to classification, to account for biological variation associated with natural environmental gradients and to improve the performance of previously developed indices.
I developed two types of model-based biological indices to quantify the biological condition of Ohio wetlands: a vegetation-based index of biological integrity (MVIBI) based on several attributes of wetland plant assemblages, and several indices of plant assemblage taxonomic completeness. I evaluated the accuracy and precision of the MVIBI relative to previously developed indices, and determined that the use of modeling techniques can significantly improve the performance of plant-based indices of biological integrity. Due to increases in accuracy and precision, use of the MVIBI should improve manager’s confidence in wetland biological condition assessments. The indices of taxonomic completeness exhibited poor performance relative to similar indices developed for other types of biological assemblages (i.e. aquatic insects, fish). I attribute poor index performance to my inability to accurately predict individual species occurrence, which is likely a result of plant communities being heavily structured by random disturbance events and biotic interactions that are difficult to account for. My results should help inform index developers of ways to potentially improve wetland condition assessment indices.
2
Schultz, Timothy Paul. "Biopolitik a practical assessment of future biowarfare /". CLICK HERE TO VIEW:, 2004. https://research.maxwell.af.mil/papers/ay2004/ari/schultz.pdf.
Testo completo
3
Kwan, Cheuk Hung. "Biosensors for biological nutrient monitoring /". View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?AMCE%202004%20KWAN.
Testo completo
4
Peters, Carolyn J. Rhodes Dent. "An assessment template for introductory college biological laboratory manuals". Normal, Ill. : Illinois State University, 2006. http://proquest.umi.com/pqdweb?index=0&did=1225152531&SrchMode=1&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1178116677&clientId=43838.
Testo completoAbstract (sommario):
Thesis (Ed. D.)--Illinois State University, 2006.Title from title page screen, viewed on May 2, 2007. Dissertation Committee: Dent Rhodes (chair), Nada Chang, Kenneth Jerich, Marilyn Morey. Includes bibliographical references (leaves 107-113) and abstract. Also available in print.
5
Widestrand, Johan. "Assessment of trichothecene contamination : chemical aspects and biological methodology /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5808-0.pdf.
Testo completo
6
Tidbury, Louise. "Development and biological assessment of prednisolone solid drug nanoparticles". Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3016766/.
Testo completo
7
Zivich, Jamie Dionne. "Biological Health Assessment of an Industrial Wastewater Treatment Facility". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/43523.
Testo completoAbstract (sommario):
The biological treatment of wastewaters from an industry was studied. Among the more important wastewater constituents of concern were high levels of suspended solids, due to graphite and nitrocellulose, the solvents, ethanol and acetone, and nitroglycerine (NG). The goal of this project was divided into four objectives.
The impacts of graphite on a microbial population were evaluated. Sequencing batch reactors (SBRs) were used to monitor the effects of graphite on mixed liquor suspended solids (MLSS), removal of soluble chemical oxygen demand (sCOD), and specific oxygen uptake rates (sOUR). Graphite appeared to have no adverse effect on the microbes.
The potential benefits of adding sucrose, nitrogen, and phosphorus to SBRs were evaluated. The MLSS was maintained at 1,250 mg/L, similar to the microbial population in the suspended growth system at the industry. Sucrose addition increased the sCOD removals and sOUR. No direct effect was observed with the addition of nitrogen and phosphorus.
The treatability of acetone and ethanol was studied through sOUR and batch testing to determine bacterial response to solvents. Both solvents were utilized by the microbes. The concentrations tested proved to be beneficial, not inhibitory. Ethanol and a 50/50 mixture of acetone and ethanol were more viable substrates than acetone.
NG treatability was examined under anoxic and aerobic conditions in SBRs and batch biological reactors. NG degradation occurred under anoxic conditions, but was more favorable in aerobic environments. NG was degraded in all SBR tests to below detection limit (0.5 mg/L); therefore, the optimal treatment could not be determined.Master of Science
8
McKinlay, Rebecca. "Risk assessment of endocrine disrupting pesticides in biological systems". Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/5585.
Testo completoAbstract (sommario):
Endocrine Disrupting Chemicals (EDCs) are a diverse array of natural and manmade substances capable of interfering with hormonally mediated processes. They are particularly harmful to cells that are differentiating and dividing rapidly, can stimulate unwanted cell growth, and can interfere with normal epigenetic imprinting causing changes that in some instances are heritable. Due to their epigenetic effects and effects on tissue growth and development, organisms at certain life stages are more vulnerable than others and effects may manifest a long time after exposure. The risks posed to human and environmental health by these compounds are currently unknown, but there is a growing scientific consensus that precautionary measures and further research to understand and quantify these risks are needed. Endocrine Disrupting pesticides represent a subset of EDC capable of reaching humans from a diverse range of sources via many different exposure routes. No definitive lists or screening methodologies exist to identify them. In the UK, exposure routes involving occupational pesticide use for agricultural purposes or the residues of these pesticides in food and water are well quantified but other sources of exposure are not. If risk management measures are to be enacted to protect the population, these exposures will have to be quantified and the risks they pose assessed. This project aims to identify the hazards posed by ED pesticides to humans living in the UK, prepare a framework for the assessment and management of risks they pose, identify the tasks that remain to be completed before such a framework could be implemented, and to investigate poorly documented ED pesticide exposure sources. Current toxicological testing of pesticides was found to be inadequate. Properties frequently exhibited by EDCs, such as non-monotonic (j-type) dose responses and the additive and synergistic actions of compounds were not taken into account. Only active ingredients are legally required to be tested even although adjuvants used to improve formulation effectiveness are not always inert and formulations can be more toxic or have greater ED potential than their active ingredients alone. Adjuvants are assessed on a reactive basis, which is not adequate to protect public health. A tiered risk assessment and management framework capable of screening potential ED pesticides and making recommendations for risk management can be created using existing deterministic and probabilistic models of human pesticide exposure. The identification of critical groups that are more vulnerable than the general population to the effects of EDCs allows risk assessment and management to be tailored to protect these groups, allowing the risk to both these groups and the general population to be minimised, in keeping with the precautionary principle. Further work is required, however, to collect appropriate datasets to model non agricultural exposure routes and model the exposure of rural residents and bystanders. Assumptions made in the creation of foreign models would need to be checked to ensure they were compatible with UK conditions. Appropriate ADIs for EDCs showing non-monotonic dose responses would also need to be determined, and exposure profile differences between people living in urban, periurban and rural environments would also have to be taken into account. A number of ED pesticides used for medicinal, veterinary and domestic purposes and the municipal and commercial maintenance of infrastructure and recreational areas were identified. Unfortunately little could be determined about the factors influencing their use by the public. The number of years spent in secondary education correlated positively with non ED medicinal pesticide use and both ED and non ED veterinary and domestic use. It was unclear why this should be. Golf courses were the most heavily treated publicly accessible areas studied and used the most ED pesticides. Large parks received least, with pesticide use concentrated on hard surfaces and high maintenance ornamental areas. Pesticide use in parks is dominated by herbicides. Applications to pavements and other publicly accessible hard surfaces consisted almost entirely of glyphosate based herbicides. Herbicide applications on pavements and in parks mostly take place in the spring and early summer. The bulk of pesticide applications on golf courses were applied in the autumn. Contractors carrying out maintenance work for local authorities were found to use more pesticides than local authority employees. Non chemical methods of ectoparasite, pest and weed prevention and control have the potential to reduce pesticide use. Some of the methods currently in use, however, were found to be more costly and challenging to implement than chemical methods. The integration of these into parasite, pest and weed prevention and control strategies where possible and their further should be encouraged.
9
Woolley, Megan Rose. "Taxonomic and palaeobiological assessment of the South African mosasaurids". Master's thesis, Faculty of Science, 2021. http://hdl.handle.net/11427/33983.
Testo completoAbstract (sommario):
South African mosasaur remains consist of a frontal with articulating portions of the parietal and postorbitofrontals (SAM-PK-5265); two dentary fragments (SAM-PK-5265) assigned to ‘Tylosaurus capensis' by Broom in 1912 (SAM-PK-5265); an undescribed muzzle unit and associated isolated teeth (CGP/1/2265) from Pondoland and a more recently discovered isolated partial vertebra from St Lucia. Some research has been done on the material, but there is still uncertainty concerning their relationships and taxonomy. This research aims to provide a taxonomic assessment of all the SA mosasaurid material to better understand their phylogenetic relationships and to place them in the context of mosasaurs from other parts of Africa and globally. In addition, isotopic analyses, micro-computed tomography (micro-CT), mineralised tissue histology and scanning electron microscopy (SEM) are applied to the SA mosasaur remains to decipher various aspects of their palaeobiology. This study identifies three mosasaur taxa from SA: Mosasaurus sp., cf. M. hoffmannii., cf. Taniwhasaurus, and cf. Prognathodon. The isolated vertebra is assigned to Mosasaurus sp., cf. M. hoffmannii. The frontal and dentary fragments (SAM-PK-5265) originally described as Tylosaurus appears to be a mix of two taxa: One of the dentary fragments possesses replacement teeth with enamel ornamentation that resembles, Ta. mikasaensis, but is tentatively assigned to cf. Taniwhasaurus based on tooth recurvature. The other dentary fragment and a frontal with articulated elements are suggested to belong to the same individual as the muzzle unit for which the suggested assignment is cf. Prognathodon. Strontium analysis of tooth enamel dated the cf. Prognathodon material to the end of the Maastrichtian (87Sr/86Sr = 0.707817; age = 66.85Ma). The cf. Taniwhasaurus dentary fragment is likely Santonian-aged, as originally indicated in 1901. SEM of enamel from cf. Prognathodon reveals a complex array of prismless enamel types and pervasive aggregations of fossilised bacteria in the underlying dentine. The δ18OPO4 derived body temperature estimate (Tb) of the cf. Prognathodon (Tb = 33.21°C) compares well with previously reported Tb for mosasaurs and may indicate that the mosasaur was capable of maintaining a Tb higher than that of the surrounding seawater.
10
Brickley, M., e Jo Buckberry. "Undertaking sex assessment". CIFA, 2018. http://hdl.handle.net/10454/17520.
Testo completo
11
De, Vos Lauren. "Biodiversity patterns in False Bay: an assessment using underwater cameras". Doctoral thesis, Faculty of Science, 2021. http://hdl.handle.net/11427/33695.
Testo completoAbstract (sommario):
Understanding how marine biodiversity is distributed, and what drives these patterns, relies on good descriptions of marine ecosystems. This information should inform the protection of biodiversity and guide its management. Relationships between marine landscapes and biodiversity therefore need to be described at scales that are useful to regional management. Simultaneous sampling of marine biodiversity and the seafloor is challenging, so baseline ecosystem descriptions are often mismatched in their abiotic and biotic components. Cameras can sample the seafloor and its associated biodiversity concurrently, with good coverage and at low cost. These are important considerations for sustainable monitoring to inform conservation management in resource-limited regions. Terrestrial landscape characterisations cannot simply be translated to the ocean because interpreting remote ocean terrain assessments in a manner relevant to ecological analysis is complicated by depth, circulation, light attenuation, and other oceanographic variables. The integration of some of these concepts into rapid marine biodiversity assessments therefore needs ground-truthing where they are applied in new regions, to advance sustainability in long-term marine monitoring. This thesis investigated the relationship between landscape composition and benthic marine biodiversity in False Bay, South Africa using novel methods that extended biodiversity sampling across more depths and habitats than any single, previous survey of the bay. This study's approach piloted sampling and interpreting the marine landscape and biodiversity over matching spatial and temporal scales. The coverage, repeatability and ecosystem-level scale applied to this study make it a useful basis to develop monitoring protocols that are appropriate to conservation management at relevant regional scales. New insights for the region include a) a new description of the seafloor using classifications that explain the variation in epibenthic megafauna and ichthyofauna communities, b) a quantitative account of the epibenthic megafauna on the eastern reefs where species diversity was highest, and c) the synthesis of seafloor descriptions with the epibenthic megafauna and ichthyofauna to describe nine regions of False Bay, relative to two previous descriptions of "grounds". Photographs and multibeam bathymetry characterised the seafloor on eight transects across the bay and were ground-truthed by grab samples repeated at representative sites. Two new classifications were applied to describe the seafloor. Horizontal seafloor heterogeneity was highest in the east, and reef was distributed along the eastern and western margins. The Collaborative and Automated Tools for Analysis of Marine Imagery (CATAMI) scheme captured accurate broad-scale descriptions of the physical landscape when applied to photographs. Grabs are still needed to provide fine-scale particle size data on soft sediments where most invertebrate diversity is likely infauna. However, CATAMI abstracts fine-scale sediment variation into simpler groupings more useful for rapid ecosystem assessment. Photographic sampling is repeatable, which is useful for long-term ecosystem monitoring. Photographs taken using a jump camera rig assessed the epibenthic megafauna across habitats and along depth gradients. Rényi diversity showed that species diversity increased in shallow waters up to 40 m, reaching a peak between 30 and 40 m, before decreasing with increasing depth. Species diversity was highest in the east, where seafloor heterogeneity was also highest. This result is interesting because eastern False Bay falls mostly outside the current marine protected area (MPA) network and has been relatively under-represented in previous surveys. The jump camera documents ecosystem-level biodiversity patterns and processes, and the random point count method in Coral Point Count (CPCe) is useful to assess community composition and cover on reefs. The relative abundance and distribution of ichthyofauna were assessed using baited remote underwater video systems (BRUVs). Fifty-seven fish species from 30 families were recorded between 4 and 84 m. Rényi diversity showed that species richness was similar for reef and sand overall, but the Shannon-Wiener diversity index (H') was significantly higher on reef sites than on sand sites (t = 1.972, p < 0.0001). Species richness for the whole bay was similar in winter and summer, which indicates that the same species are likely present year-round; however, the Shannon-Wiener diversity index was significantly higher in winter (t = 1.973, p < 0.013) and evenness was greater in winter at the level of the site. These findings highlight the difficulty in protecting sufficient sand habitat to encompass the patchy distribution of sand-associated species and highlight seasonal differences in optimal visibility for future camera monitoring surveys by conservation management. There are clear patterns in the marine biodiversity of False Bay, at various scales, that can be detected using novel methods for the region. The study's approach to classifying both the landscape and its associated biodiversity creates a framework for future ecosystem threat assessment that can be applied elsewhere, especially along the South African coastline.
12
Hayes, Keith Robert. "Quantitive ecological risk assessment a ballast-water case study". Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/1230.
Testo completo
13
Alizadeh, Noghani Mahsa. "Progesterone-binding modified hyperbranched polyglycerols : synthesis, characterization and biological assessment". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57663.
Testo completoAbstract (sommario):
Traumatic brain injury (TBI) has been proven as an established risk factor of Alzheimer’s disease (AD). Historically, progesterone (Pro) has been found to promote recovery from moderate TBI. However, the utility of this drug as a TBI treatment is severely hampered by its near total insolubility in water due to its hydrophobicity, which contributes to an inability to rapidly administer the drug after injury.
The present work describes the synthesis, characterization, development and in vitro evaluation of nanoparticulate formulations of Pro for treatment of TBI. The nanoparticles developed for Pro consist of a library of hyperbranched polyglycerols (HPGs), which were hydrophobically modified with alkyl chains (C₆,₈,₁₀,₁₂,₁₄,₁₈) to enable loading the hydrophobic drug, and were further modified with MPEG chains to increase the solubility and stability of the formulations. Hydrophobically derivatized HPGs (HPG-Cn-MPEG), also known as dHPG(Cn), were characterized by GPC and NMR methods. Pro encapsulation by and release from the drug-binding pocket was determined through a reverse-phase UPLC method. Combination of binding, release and kinetic studies of the dHPG(Cn)/Pro library presented a relatively high number of drug molecules encapsulated, slow release and stable formulations.
In vitro assays, including blood biocompatibility, cytotoxicity and cellular uptake, were performed on dHPG(Cn)/Pro. Blood biocompatibility studies demonstrated that the polymer-drug formulations do not cause significant changes in blood coagulation time (APTT assay), nor have they significant effects on red blood cell aggregation, lysis or platelet aggregation. There was no platelet activation observed in this study. Study of viability of human cortical microvascular endothelial cells and human astrocytoma cells in the presence of dHPG(Cn)/Pro demonstrated no toxicity. Studies on the same cells presented significant uptake with relatively even distribution of the formulation inside the cells. Further investigations indicated no degradation pathway for dHPG(Cn) over short periods of time (~ 8 h). Overall, the in vitro studies suggest that dHPG(Cn) are compatible and harmless to cells, suitable for carrying hydrophobic drugs and molecules, such as Pro, to the target tissues.Science, Faculty of
Chemistry, Department of
Graduate
14
Scott, Casey G. "Biological water quality assessment of the Little Wolf River watershed /". Link to full text, 2007. http://epapers.uwsp.edu/thesis/2007/scott.pdf.
Testo completo
15
Terrill, Paul Kenneth. "Statistical models in the assessment of biological control of insects". Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263695.
Testo completo
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Zhigila, Daniel Andrawus. "Molecular phylogenetics, taxonomy and niche-based conservation risk assessment of Thesium L. (Santalaceae)". Doctoral thesis, Faculty of Science, 2020. http://hdl.handle.net/11427/33064.
Testo completoAbstract (sommario):
Thesium L. (Santalales: Santalaceae) is a large (360 species) genus of hemiparasitic perennial or annual species with a mainly Old-World distribution and a greatest concentration in southern Africa (ca. 186 species). Although Thesium is a major component of southern African flora, it often goes unnoticed and is poorly studied. The last revision of the entire genus was done by De Candolle in 1857. South African Thesium was last revised by Hill almost a century ago. Since Hill's revision, the number of collections have grown, and 49 new species have been described. Currently, no comprehensive Thesium taxonomic key exists, and species delimitation remains difficult due to a high variation in character states, rendering the genus in need of major revision. Within southern Africa, ca. 103 species occur in the Greater Cape Floristic Region (GCFR), of which about 72 are regional endemics. The GCFR Thesium, including ecologicalspecialists and generalists, offers an appropriate system for evaluating both the correlates of range extent, specialisation and the relative extinction risks associated with both ecological strategies. Here, it is predicted that a combination of edaphic, elevation and climate variables influence the geographic range of Thesium in the GCFR. Recent phylogenetic hypotheses revealed that Thesium is paraphyletic with respect to Austroamericium, Chrysothesium, Kunkeliella and Thesidium, suggesting the need for generic realignment. In addition, existing subgeneric and sectional classifications of this large genus lack a phylogenetic basis, thus compromising their predictive value. Using an expanded taxon sampling and a combination of nuclear (ITS) and chloroplast (matK, rpl32- trnL and trnL-F) DNA sequence data, chapter two re-assesses the phylogenetic relationships of Thesium and uses these as the basis of a new subgeneric classification of the genus. The phylogeny obtained confirms the need to place the four segregate genera into synonymy, resulting in a monophyletic Thesium. In addition, it resolves five, well-supported major clades within Thesiumwhich I recognize as subgenera. The South African endemic subgenus Hagnothesium is sister to the Eurasian subgenus Thesium (including Thesium, Kunkeliella and Mauritanica). The subgenus Psilothesium, occurring in tropical South America (formerly genus Austroamericium) and tropical Africa, is sister to the rest of the subgenera, which are all confined to South Africa. Within the latter, the subgenus Discothesium consists of subtropical and temperate species, whereas subgenus Frisea, comprising previously recognized sections Annulata, Barbata Frisea, Imberbia and Penicillata, is restricted to the GCFR. To facilitate identification of subgenera, I present identification keys, assigned species, provide brief diagnoses, identified ancestral morphological characters and, supply distribution and ecological data. Thesium subgenus Hagnothesium is endemic to the GCFR. In the past, there has been a propensity in revisionarywork ofthe subgenus Hagnothesium to split taxa into distinctspecies or vice-versa. Consequently, 15 different names exist although only six are accepted formally. Following recent molecular phylogenetic studies, the monophyly of the subgenus Hagnothesium is now well-established, but the circumscription of species within the section remains problematic given the complicated nomenclatural history which has added further confusion. Chapter three presents a revision of subgenus Hagnothesium using a total evidence approach to propose a modern taxonomy. I studied both herbarium collections and plants in their natural populations to circumscribe species boundaries, geographical ranges and estimates of their conservation status. Species of the subgenus Hagnothesium are dioecious, generally having four- merous, campanulate flowers, spikes borne in bract axils and arranged along the length of branchlets, with valvate perianth lobes and a short to absent hypanthial tube. The following eight species were recognized, of which one is here described as new: T. fragile L.f., T. fruticulosum (A.W.Hill) J.C.Manning & F.Forest, T. hirtum (Sond.) Zhigila, Verboom & Muasya comb. nov., T. leptostachyum A.DC., T. longicaule Zhigila, Verboom & Muasya nom. nov., T. microcarpum A.DC., T. minus (A.W.Hill)J.C.Manning & F.Forest and T. quartzicolum Zhigila, Verboom & Muasya sp. nov. I provide updated taxonomic keys, species descriptions, illustrations, distribution maps, new combinations, synonyms, and notes on the red list status for each species. In addition, six new species of Thesium endemic to the GCFR (but not included in subgenus Hagnothesium) are described and illustrated in chapter four. These are: Thesium aspermontanum Zhigila, Verboom & Muasya sp. nov., T. dmmagiae Zhigila, Verboom & Muasya sp. nov., T. neoprostratum Zhigila, Verboom & Muasya sp. nov., T. nigroperianthum Zhigila, Verboom & Muasya sp. nov., T. rhizomatum Zhigila, Verboom & Muasya sp. nov., and T. stirtonii sp. nov. Also, Thesium assimile var. pallidum is elevated to species rank as T. sawae Zhigila, Verboom & Muasya stat. nov. Morphological and ecological differences between species, along with their putative affinities, preliminary conservation status, phenology, etymology and distributional maps are presented. Narrow-ranged species are expected to be more at greater risk of extinction than generalists due to climate change. Such risk is greatest in biodiversity hotspots such as the GCFR, which house both ecological specialists and generalists. It was hypothesized that range size, ecological specialization and consequent climatically-modulated extinction-risk are all phylogenetic structured, such that climate change will precipitate a disproportionate loss of phylogenetic diversity. Past and future species distribution ranges were developed using MaxEnt models based on present-day occurrences and environmental conditions. There was a strong positive correlation between the ecological niche breadth of species, as determined by large-scale environmental variables, and their range extents. One hundred and one Thesium species were modelled, of which 71 species (83%) were predicted to have had broad range sizes during the Last Glacial Maxima, and 27 species (17%) recorded range contractions historically to the present. Similarly, 45 species (44%) will potentially expand their ranges, while 51 species (50%) are predicted to reduce their ranges in the future. Of the 65 species currently ranked as Least Concern or Data Deficient in the South African Red list, 24 species will likely shift into higher extinction risk categories. Interestingly, five ecological specialists (5%), although having experienced a range reduction from the LGM to the present, are predicted to persist in the face of future climate change. However, the range extent, ecological specialisation and extinction risk are phylogenetically random and therefore should have a negligible impact on the phylogenetic diversity of the GCFR Thesium. Overall, this study confirms the monophyly of the genus Thesium and sets its infrageneric classification scheme in place. The context of this classification framework allows the systematic revision of the genus, one clade at a time. Towards this goal, I revised the Hagnothesium clade and additionally described six new species from other clades. The climate, elevation and soil variables influence the distribution range and specialism of GCFR Thesium clades. However, ecological specialism of species and extinction risks were predicted to be phylogenetically random.
17
Keatinge, Zoe Alexandra Frances. "Soil contamination in urban Tyneside : a chemical and biological risk assessment". Thesis, University of Newcastle Upon Tyne, 2006. http://hdl.handle.net/10443/233.
Testo completoAbstract (sommario):
The extent of soil contamination with organic and inorganic pollutants in most urban areas in the UK is largely unknown but due to past and present industrial activity it is likely that pollutant levels are high. Such contamination could have a serious impact on human health. Therefore this thesis set out to examine the extent of soil contamination within Newcastle upon Tyne with a focus on the contribution of an incinerator (Byker) to contamination levels of urban soils. The Byker incinerator is situated in central Newcastle and has been the subject of much media controversy due to the disposal of incinerator ash on local allotments. The current work extended past investigations to see if the incinerator had contributed to general urban soil pollution (heavy metals and dioxins) by aerial deposition and allowed a useful investigation into levels of urban soil contamination in Newcastle. In addition to examining metal and dioxin levels the bioaccessibility (human and bacterial) of pollutants in selected soil samples was estimated and an attempt to develop a human cell based soil toxicity assay made. These measurements permit a preliminary assessment of risk to human health from soil contamination. A total of 163 soil samples were collected based on predicted aerial deposition from the Byker incinerator and analysed for dioxins and heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb & Zn) content (mg pollutant /kg soil). A high proportion of samples (90/163) had contamination levels above soil guideline values (as proscribed in current UK regulations; CLEA). The highest dioxin levels were South West of the incinerator (1911 ng I-TEQ/kg) and the congener profiles coupled with a detailed historical survey demonstrated that the source of contamination was likely to be an old alkali works and not the incinerator. Overall it was found that the incinerator did not contribute significantly to dioxins found in the urban soils except those in the incinerator plant grounds. Soil metal contamination levels varied but were not related to incinerator deposition. Many samples contained levels of heavy metals well over soil guideline values with the highest values being found for Cu (12,108 mg/kg), Pb (4,134 mg/kg) and Zn (4,625 mg/kg) To determine the potential human health risk associated with heavy metal contaminated soils, selected samples (16) were subjected to two in vitro digestion techniques which simulate the bioaccessibility of metals (Cu, Ni, Pb & Zn) to humans in case of soil ingestion. Only three samples had high levels of metal availability (over SGV's) indicating that these soils should be subjected to further risk assessment. All other samples tested had low metal availability most likely due to a combination of metal speciation, and complexation to soil particles over time. An attempt was made to develop a human cell based system to determine the toxicity of contaminated soil. Using an in vitro system, human liver cells (HepG2's) were exposed to extracts from soils; cytotoxic effects (membrane integrity, metabolic capability and oxidative stress status) and genotoxicity potential (DNA damage) of Cu and Zn were first investigated in order to standardise the biological assays used. Between 0.1 and 10 mg/L Cu caused DNA damage and higher concentrations caused cytotoxicity. Zn was also proven to cause genotoxic effects from O. lmg/L. From 10 mg/L cytotoxic responses occurred and DNA damage could be attributed to cell death. Due to difficulties in sterilising soil extracts and physical damage caused to HepG2 cells by the abrasive nature of soil, it was not possible to elucidate whether metal contaminated soil extracts were capable of causing a cytotoxic or genotoxic response in human liver cells. Finally, the same soil samples were then subjected to a bacterial (lux) biosensor technique to examine soil toxicity. Interestingly, despite the high levels of contamination found, none of the soil samples were found to be toxic to the two Pseudomonas strains used which again indicates a low level of ecosystem risk and suggests that most of the contaminants present are either in a form that is unavailable to living microbes or are complexed to soil particles. In summary, this research has shown that the high level of soil contamination of urban areas in Newcastle is due to past industrial activity and a similar situation is likely in most other urban areas of the UK and internationally. The high cost of remediation means that if contaminated sites are shown to be a potential risk then bioaccessibility of contaminants should be examined in order to provide a more realistic assessment of the need for remediation. This work demonstrates that only a small proportion of urban contaminated sites are likely to require remediation based on bioaccessibility determination measurements.
18
Holtman, Gareth Alistair. "Design, installation, and assessment of a biological winery wastewater treatment system". Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2573.
Testo completoAbstract (sommario):
Thesis (MTech (Civil Engineering))--Cape Peninsula University of Technology, 2017.Currently in South Africa, most wastewater from small cellars is pH-adjusted and disposed of via land irrigation. This practice can lead to environmental degradation. There is a need for low cost, low maintenance solutions for the treatment of cellar effluent. Constructed wetlands provide such an option. However, the use of plants is problematic because winery effluent can be phytotoxic. After successful initial laboratory-scale experiments, an in-situ pilot scale biological sand filter (unplanted constructed wetland) system was designed, installed, and used to treat effluent from a small winery in the Western Cape, South Africa. The system is off-grid, totally self-regulating, and uses a modular approach which allows for the addition and subtraction of filter modules within the system to alter treatment capacity, retention time and/or rest filter modules. The system can be easily integrated into existing settling basins and/or retention ponds at small wineries. The biological sand filter was operational for 610 days, and showed promising results. The average chemical oxygen demand removal efficiency was 81% (range: 44-98%) with an average effluent of 324 mg/L, and an average flow rate of 413 L/day after the acclimation (start-up) period. The average hydraulic loading rate after the initial start-up period was 143 L/m3 sand day-1 (range: 67-222/m3 sand day-1), with an organic loading rate of 205 gCOD/m3 of sand day-1 (range: 83-338 gCOD/m3 sand day-1) which resulted in an organic removal rate of 164 gCOD/m3 of sand day-1. There was an average of 67% removal of total phenolics, thereby reducing the potential phytotoxicity of the effluent. In addition, there was a 1.6 times increase in calcium concentration, a 29% decrease in the average sodium adsorption ratio, and complete passive neutralisation of the acidic winery wastewater (final effluent pH range: 6.63 – 8.14. The findings of this study compare well with previous laboratory studies conducted with synthetic and authentic winery effluent. The system can potentially provide a low cost, energy efficient, low maintenance, sustainable means of treating cellar effluent at small wineries. Uptake of this technology may alleviate environmental degradation caused by irrigating land with inadequately treated effluent.
19
Sun, Ye. "Studies on Spring Conservation: Biological Indicators, Habitat Classification and its Assessment". Kyoto University, 2020. http://hdl.handle.net/2433/253446.
Testo completoAbstract (sommario):
付記する学位プログラム名: 京都大学大学院思修館Kyoto University (京都大学)
0048
新制・課程博士
博士(総合学術)
甲第22610号
総総博第10号
新制||総総||2(附属図書館)
京都大学大学院総合生存学館総合生存学専攻
(主査)教授 山敷 庸亮, 准教授 趙 亮, 准教授 竹門 康弘
学位規則第4条第1項該当
20
Poolsup, Nalinee. "Quantitative assessment of the pharmacotherapy of bipolar disorder and schizophrenia". Thesis, Aston University, 2000. http://publications.aston.ac.uk/10981/.
Testo completoAbstract (sommario):
The work present in this thesis was aimed at assessing the efficacy of lithium in the acute treatment of mania and for the prophylaxis of bipolar disorder, and investigating the value of plasma haloperidol concentration for predicting response to treatment in schizophrenia. The pharmacogenetics of psychotropic drugs is critically appraised to provide insights into interindividual variability in response to pharmacotherapy, In clinical trials of acute mania, a number of measures have been used to assess the severity of illness and its response to treatment. Rating instruments need to be validated in order for a clinical study to provide reliable and meaningful estimates of treatment effects, Eight symptom-rating scales were identified and critically assessed, The Mania Rating Scale (MRS) was the most commonly used for assessing treatment response, The advantage of the MRS is that there is a relatively extensive database of studies based on it and this will no doubt ensure that it remains a gold standard for the foreseeable future. Other useful rating scales are available for measuring mania but further cross-validation and validation against clinically meaningful global changes are required. A total of 658 patients from 12 trials were included in an evaluation of the efficacy of lithium in the treatment of acute mania. Treatment periods ranged from 3 to 4 weeks. Efficacy was estimated using (i) the differences in the reduction in mania severity scores, and (ii) the ratio and difference in improvement response rates. The response rate ratio for lithium against placebo was 1.95 (95% CI 1.17 to 3.23). The mean number needed to treat was 5 (95% CI 3 to 20). Patients were twice as likely to obtain remission with lithium than with chlorpromazine (rate ratio = 1.96, 95% CI 1.02 to 3.77). The mean number needed to treat (NNT) was 4 (95% CI 3 to 9). Neither carbamazepine nor valproate was more effective than lithium. The response rate ratios were 1.01 (95% CI 0.54 to 1.88) for lithium compared to carbarnazepine and 1.22 (95% CI 0.91 to 1.64) for lithium against valproate. Haloperidol was no better than lithium on the basis of improvement based on assessment of global severity. The differences in effects between lithium and risperidone were -2.79 (95% CI -4.22 to -1.36) in favour of risperidone with respect to symptom severity improvement and -0.76 (95% CI -1.11 to -0,41) on the basis of reduction in global severity of disease. Symptom and global severity was at least as well controlIed with lithium as with verapamil. Lithium caused more side-effects than placebo and verapamil, but no more than carbamazepine or valproate. A total of 554 patients from 13 trials were included in the statistical analysis of lithium's efficacy in the prophylaxis of bipolar disorder. The mean follow-up period was 5-34 months. The relapse risk ratio for lithium versus placebo was 0.47 (95% CI 0.26 to 0.86) and the NNT was 3 (95% CI 2 to 7). The relapse risk ratio for lithium versus imipramine was 0.62 (95% CI 0.46 to 0.84) and the NNT was 4 (951% Cl 3 to 7), The combination of lithium and imipramine was no more effective than lithium alone. The risk of relapse was greater with lithium alone than with the lithium-divalproate combination. A risk difference of 0.60 (95% CI 0.21 to 0.99) and an NNT of 2 (95% CI 1 to 5) were obtained. Lithium was as effective as carbamazepine. Based on individual data concerning plasma haloperidol concentration and percent improvement in psychotic symptoms, our results suggest an acceptable concentration range of 11.20-30.30 ng/mL A minimum of 2 weeks should be allowed before evaluating therapeutic response. Monitoring of drug plasma levels seems not to be necessary unless behavioural toxicity or noncompliance is suspected. Pharmacokinetics and pharmacodynamics, which are mainly determined by genetic factors, contribute to interindividual and interethnic variations in clinical response to drugs. These variations are primarily due to differences in drug metabolism. Variability in pharmacokinetics of a number of drugs is associated with oxidation polymorphism. Debrisoquine/sparteine hydroxylase (CYP2D6) and the S-mephenytoin hydroxylase (CYP2C19) are polymorphic P450 enzymes with particular importance in psychopharmacotherapy. The enzymes are responsible for the metabolism of many commonly used antipsychotic and antidepressant drugs. The incidence of poor metabolisers of debrisoquine and S-mephenytoin varies widely among populations. Ethnic variations in polymorphic isoenzymes may, at least in part, explain ethnic differences in response to pharmacotherapy of antipsychotics and antidepressant drugs.
21
Schaefer, Sandra M. "An Assessment of Methods for Testing the Reliability of Wildlife Occurrence Models Used in Gap Analysis". Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/SchaeferSM2002.pdf.
Testo completo
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Horton, Matt. "Age, growth and per-recruit assessment of the Saldanha and Langebaan stock of Chelon richardsonii". Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29745.
Testo completoAbstract (sommario):
Chelon richardsonii are omnivorous, particle feeders found specifically within inshore and estuarine habitats on the west and south coast of South Africa. They are the primary target of the gillnet and beach-seine fishery in this region. Despite being managed through a multifaceted approach of gear restrictions and total allowable e↵ort, the fishery is thought to be oversubscribed and the stock is regarded as being overfished. The social and economic importance of this fishery necessitates an update of the life history parameters of C. richardsonii to enable an accurate assessment the current status of the stock. The fishery in Saldanha and Langebaan was described via investigating changes in sexratio, mean length (mm) and standardised catch-per-unit-e↵ort (CPUE). Firstly, exploration of sex ratio indicated a significant switch between the two periods (1998-2002 and 2017), resulting in a predominantly male biased population (1.7 males: 1 female). Secondly, through investigation of three length-frequency distributions of commercial catch of C. richardsonii (1998-2002, 2009-2011 and 2017) a reduction in mean total length (TL) of 36.5 mm was observed. Lastly, the standardisation of the Netfishery CPUE for the time series of 2008-2016 through the application of a Generalised Additive Mixed Model (GAMM) showed a reduction of approximately 30% in relative abundance of C. richardsonii. Chelon richardsonii exhibited a fast growth, a maximum age of six and matured relatively early at two years old. Growth was best described using a three parameter von-Bertalan↵y growth model; where L1 is the asymptotic length, K is the rate at which L1 is reached and t0 is the age when the average length is zero. The data collected in 2017 expressed two problems. Firstly, as a result of high gillnet selectivity, smaller individuals within younger age classes were missing. Secondly, due to growth overfishing and/or a small sample size (n = 353) older and larger adults were missing. Consequently, this increasesd K and decreased L1 to biologically implausible values (female original growth: L1 = 257.450 mm, K = 0.610 year-1 and t0 = -0.040 year). As a result L1 was fixed in accordance to a historic Lmax, in order to overcome these issues and produce biologically plausible growth parameters. Growth di↵ered significantly between males and females, hence female growth was subsequently used for the spawner biomass-per-recruit analysis in the proceeding chapter (L1 = 347.400 mm, K = 0.235 year-1 and t0 = -0.833 year). Total mortality (Z) and average natural mortality (M ) were estimated as 1.466 year-1 and 0.329 year-1, respectively. i 0 ii Growth and mortality was constant in Chelon richardsonii throughout Saldanha and Langebaan and despite potential emigration out of the bay, the sup-population of C. richardsonii was considered to be a discrete stock for the purpose of this study. A spawner biomass-pre-recruit model, based on the growth and mortality parameters calculated in Chapter 3, revealed that the stock is heavily depleted and recruitment is likely to be seriously impaired (spawner biomass-per-recruit = 5.5% of pristine levels). It must be acknowledged that the results of a per-recruit stock assessment heavily depend on the growth model parameters. In contrast, the model indicated an optimally exploited stock when the original growth parameters were applied (spawner biomass per-recruit = 76.2% of pristine levels). Considering results from Chapter 2 and the justifications for fixing L1 the plausibility of the second scenario being true is less likely. Acknowledging the temporal, spatial and sample size limitations of this study conclusions made will require definitive future examination. Regardless, a reduction in fishing e↵ort and further restrictions in mesh sizes are suggested to facilitate the replenishment and sustainable use of the stock.
23
Guerci, Michael John. "Economic Feasibility of a Biological Control Cottage Industry in Niger". Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/72953.
Testo completoAbstract (sommario):
This study evaluates the economic feasibility of a biological control industry in Niger. Farmers in the Sahel region of Niger are vulnerable to high millet yield losses due to the millet head miner, and their pest control options are extremely limited. Researchers have begun to support small businesses which sell a beneficial insect (Habrobracon Hebetor) that is very effective in limiting millet yield losses due to the millet head miner. This study discusses a wide range of questions related to the economic prospects of these businesses using two main analytical methods, an economic feasibility assessment and an econometric analysis. The economic feasibility assessment provides budget analysis for the potential businesses and discusses business options for scaling, price setting, and organizing. A central question in this analysis is whether farmers can cooperatively purchase beneficial insects as a means of preventing free-riding. With free-riding as a prominent concern for businesses, this study also provides an econometric analysis of the factors that affect farmer's willingness-to-pay for beneficial insects.Master of Science
24
Ashcroft, Darren M. "Applying quantitative methods in the assessment of outcomes of pharmacotherapy of psoriasis". Thesis, Aston University, 1999. http://publications.aston.ac.uk/10941/.
Testo completoAbstract (sommario):
Healthcare providers and policy makers are faced with an ever-increasing number of medical publications. Searching for relevant infonnation and keeping up to date with new research findings remains a constant challenge. It has been widely acknowledged that narrative reviews of the literature are susceptible to several types of bias and a systematic approach may protect against these biases. The aim of this thesis was to apply quantitative methods in the assessment of outcomes of topical therapies for psoriasis. In particular, to systematically examine the comparative efficacy, tolerability and cost-effectiveness of topical calcipotriol in the treatment of mild-to-moderate psoriasis. Over the years, a wide range of techniques have been used to evaluate the severity of psoriasis and the outcomes from treatment. This lack of standardisation complicates the direct comparison of results and ultimately the pooling of outcomes from different clinical trials. There is a clear requirement for more comprehensive tools for measuring drug efficacy and disease severity in psoriasis. Ideally, the outcome measures need to be simple, relevant, practical, and widely applicable, and the instruments should be reliable, valid and responsive. The results of the meta-analysis reported herein show that calcipotriol is an effective antipsoriatic agent. In the short-tenn, the pooled data found calcipotriol to be more effective than calcitriol, tacalcitol, coal tar and short-contact dithranol. Only potent corticosteroids appeared to have comparable efficacy, with less shorttenn side-effects. Potent corticosteroids also added to the antipsoriatic effect of calcipotriol, and appeared to suppress the occurrence of calcipotriol-induced irritation. There was insufficient evidence to support any large effects in favour of improvements in efficacy when calcipotriol is used in combination with systemic therapies in patients with severe psoriasis. However, there was a total absence of long-tenn morbidity data on the effectiveness of any of the interventions studied. Decision analysis showed that, from the perspective ofthe NHS as payer, the relatively small differences in efficacy between calcipotriol and short-contact dithranol lead to large differences in the direct cost of treating patients with mildto- moderate plaque psoriasis. Further research is needed to examine the clinical and economic issues affecting patients under treatment for psoriasis in the UK. In particular, the maintenance value and costlbenefit ratio for the various treatment strategies, and the assessment of patient's preferences has not yet been adequately addressed for this chronic recurring disease.
25
Annaz, Basil. "In vitro assessment of the biological role of microporosity synthetic porous hydroxyapatite". Thesis, Queen Mary, University of London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405697.
Testo completo
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Jones, Dan. "The characterisation and biological assessment of novel porous structures for orthopaedic application". Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539613.
Testo completo
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Magnusson, Karin. "Poly-and oligothiophenes : Optical probes for multimodal fluorescent assessment of biological processes". Doctoral thesis, Linköpings universitet, Kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-121815.
Testo completoAbstract (sommario):
One interesting class of molecules in the research field of imaging biological processes is luminescent conjugated polythiophenes, LCPs. These fluorescent probes have a flexible backbone consisting of repetitive thiophene units. Due to this backbone, the probes possess unique abilities to give rise to different spectral signatures depending on their target and environment. LCPs are a polydispersed material meaning there is an uneven distribution of lengths of the probe. Recently, monodispersed chemically well-defined material denoted luminescent conjugated oligothiophenes, LCOs, with an exact number of repetitive units and distinct sidechain functionalities along the backbone has been developed. LCOs have the advantages of being smaller which leads to higher ability to cross the blood brain barrier. The synthesis of minor chemical alterations is also more simplified due to the well-defined materials. During my doctoral studies I have used both LCPs and LCOs to study biological processes such as conformational variation of protein aggregates in prion diseases and cellular uptake in normal cells and cancer cells. The research has generally been based on the probes capability to emit light upon irradiation and the interaction with their targets has mainly been assessed through variations in fluorescence intensity, emission-and excitation profiles and fluorescence lifetime decay. These studies verified the utility of LCPs and LCOs for staining and discrimination of both prion strains and cell phenotypes. The results also demonstrated the pronounced influence minor chemical modifications have on the LCO´s staining capacity.
28
Douek, Michael. "Contrast enhanced MRI in the biological and functional assessment of breast cancer". Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247999.
Testo completo
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Clarke, Stewart Jonathon. "Sediment-macrophyte relationships in lowland English rivers : using macrophytes for biological assessment". Thesis, Queen Mary, University of London, 2000. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1395.
Testo completoAbstract (sommario):
A study of the relationship between submerged-rooted aquatic macrophytes and the chemical and physical characteristics of sediments in lowland British rivers is described. The focus of the research is the spatial variability of nutrient concentrations in river sediments and the preferences of particular macrophyte species for different sediment types. This information is required to further develop the use of macrophytes in the biological assessment of rivers. Sediment samples were collected from beneath macrophyte stands and unvegetated areas of the riverbed in 17 rivers. The sediment samples were analysed for total and inorganic phosphorus, total nitrogen, organic carbon, organic matter and silt-clay content. Data on water chemistry flow regimes, channel geometry and macrophyte habitat were also collected. Sediments were found to exhibit a high degree of variability both within 100m sites and between the different rivers, particularly with respect to phosphorus concentrations. There were relationships between sediment concentrations of total and inorganic phosphorus and between concentrations of total nitrogen, organic carbon and organic matter. No clear relationships between mean values for sediment parameters and either water column nutrient concentrations or flow regime were apparent. The significance of the sediment variables as a control on macrophyte community structure was investigated through the use of canonical ordination and discriminant analysis. Macrophyte species showed broad tolerances to all sediment variables and it was not possible to separate the influence of sediment nutrients from other sediment parameters or differences between rivers. Comparisons of water sediment and plant tissue nutrient concentrations at sites upstream and downstream of waste water treatment work outfalls on two rivers indicated that the discharges affected both the water and sediment concentrations but not plant tissue levels. The research suggests that the relationships between macrophytes and sediments in lowland rivers are complex and confounded by the effect of the plants themselves upon flow and sediment dynamics.
30
Bickett-Weddle, Danelle. "Development and initial validation of a dairy biological risk management assessment tool". [Ames, Iowa : Iowa State University], 2009.
Cerca il testo completo
31
Brooks, John P. "Biological aerosols generated from the land application of biosolids: Microbial risk assessment". Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280590.
Testo completoAbstract (sommario):
In the United States greater than 6 million dry tons of biosolids are produced nationwide, with greater than 60% being land applied. Although most counties utilizing land application are practicing this beyond nearby homes, the increase in population has begun to blur the line between rural and urban communities. This study was conducted to investigate the occurrence of biological aerosols (bioaerosols) containing microorganisms and endotoxins, and assess the human health risk involved in these practices. Aerosol samples were collected for 2 years from land application sites located at various locations throughout the U.S.A., which represented different climatic conditions and different application practices. Land application practices involved the use of liquid biosolids spray and "cake" biosolids applicators depending on location. Bioaerosols were collected via the use of six SKC Biosamplers, impinging air at a rate of 12.5 L/min for a total of 20 minutes. Samples were collected from both downwind of land application and background sites from distances ranging between 2 m and 70 m downwind. Microbial concentrations were measured within these aerosols, measurements included: heterotrophic plate count bacteria (HPC), coliphage, Clostridium perfringens, total coliforms, Escherichia coli, endotoxin (lipopolysaccharide), enteroviruses, norovirus, and Hepatitis A virus (HAV). In addition a model was developed to predict viral transport. Overall the levels of aerosolized indicator bacteria and phage were at or below detection limits. Three samples were positive for the presence of norovirus viral RNA via reverse transcriptase polymerase chain reaction, although their viability was unable to be determined based on current available techniques. Calculated microbial risks of infection were determined to be at or below the acceptable risk of annual infection from drinking water proposed by the Environmental Protection Agency, 1:10,000. Biosolids loading scenarios presented the greatest risk of infection, partly due to the point source of exposure. All other portions of biosolids land application operations yielded risks of infection well below the annual 1:10,000 risk of infection. Overall the microbial aerosol exposures brought about by land applied biosolids are minimal and hence minimal overall risks of infection.
32
Ali, Tonima S. "Transverse relaxation based magnetic resonance techniques for quantitative assessment of biological tissues". Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/131192/1/Tonima_Ali_Thesis.pdf.
Testo completoAbstract (sommario):
Using transverse relaxation based MRI, this thesis has developed new quantitative approaches to characterise the progression of Osteoarthritis in animal models and has introduced this type of characterisation for the assessment of mammographic density. For the first time, it has identified the collagen architecture in the kangaroo knee cartilages using MRI. The three case studies presented in this thesis have experimentally investigated and evaluated the analytical efficacy of the transverse relaxation based techniques and quantitative T2 measurements. It has also identified previously unknown information on the composition of native and pathological tissues and thereby demonstrated the suitability of the application of transverse relaxation based techniques for comprehensive assessment of biological tissues and organs. The imaging and analysis protocols developed in these works are completely non-invasive and are transferrable to clinical scanners in principle.
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Alqahtani, Ali Saeed. "Quality Assessment and Biological Activities of Centella Species in Diabetic Wound Healing". Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14038.
Testo completoAbstract (sommario):
The aim of this study was to differentiate Australian Centella species using morphological, genetic and phytochemical methods, and to evaluate their antiglycation and cell protection activities in relation to diabetic wound healing. The morphometric multivariate analysis successfully grouped the samples into three clusters: C. asiatica, C. cordifolia and C. erecta. Inter Simple Sequence Repeat (ISSR) genetic markers classified the samples according to the three species where C. erecta was the most genetically distinct. Multivariate chemometrics of HPTLC profiles of saponins and phenolics separated C. erecta from other two species. The total triterpene and phenolic content as well as chlorogenic acid were higher in C. cordifolia and lower in C. erecta. Ethyl acetate fraction of C. cordifolia exerted the most potent antioxidant and antiglycation activities. It ameliorated the MGO-induced inhibition of endothelial cells, fibroblasts and keratinocytes adhesion on extracellular matrix proteins. The results indicate that ISSR molecular techniques combined with morphological examination and phytochemical analysis are effective for quality assessment and systematic studies of Centella. These methods have enabled the differentiation of three Centella species in Australia. C. cordifolia is a potential candidate for further development as a medicinal product for diabetic wound healing.
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Hang, Ta-Chun. "Optimization of primary endothelial culture methods and assessment of cell signaling pathways in the context of inflammation". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/71467.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biological Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references.
Tissue engineering is a potentially valuable tool for clinical treatment of diseases where host tissues or organs need to be replaced. Progression of engineering metabolically complex organs and tissues has been severely limited by the lack of established, functional vasculature. The thesis work described herein focused on methods of establishing and studying specific endothelial cell types in vitro for potential applications in establishing functional microvascular architecture. To achieve these objectives, a model system of primary liver sinusoidal endothelial cells (LSEC) was initially studied due to the high metabolic requirements of the liver, as well as the unique phenotype that they possess. We were able to demonstrate that free fatty acids were able to rescue LSEC in culture, promote proliferation, and maintain their differentiated phenotype. Our work with lipid supplementation in serum-free conditions provides flexibility in engineering liver tissue with a functional vasculature comprised with relevant endothelial types encountered in vivo. Following up our work with LSEC, we explored the human dermal microvascular endothelial cell (HDMVEC) system to understand the signaling mechanisms involved in sprouting angiogenesis. Engineered tissues that are implanted will require integration with host vasculature. We established a method to collect large signaling data sets from a physiologically relevant in vitro culture system of HDMVEC that permitted angiogenic sprouting. We were able to find statistically significant data regarding how angiostatic cues like Platelet Factor 4 can modulate angiogenesis signaling pathways. Our results from working with both types of endothelial cell systems provide insight into potential methods for establishing specialized microvasculature for engineered tissues, both in propagation of differentiated endothelial cells in vitro and promotion of tissue/organ survival following their implantation.
by Ta-Chun Hang.
Ph.D.
35
Al-Hafidh, Alawi Salim Ali. "Assessment and management of the abalone (haliotis mariae, Wood 1828) stock in the Omani waters". Thesis, University of Hull, 2006. http://hydra.hull.ac.uk/resources/hull:5661.
Testo completoAbstract (sommario):
This study investigates the status of Abalone fishery (Haflotis mariae) in the southern region of Oman. This fishery has been an important and valuable resource to both the population in this region as well as for the country. The fishery began around 1970 and produces annually between 29-56 t of fresh meat with the highest production during 2003 valued at 8.4 million US$, (but most of the landing during the last few years is below the minimum legal size of 90 mm shell length). This extraordinarily value has resulted in intensive fishing operations and the fishery today faces a serious decline in stock density and availability of large individuals. This study aims to assess the reasons for the decline, and provide information on the status of the fishery to develop a management plan. The study was carried out over two years including monthly sampling from three selected permanent stations: Mirbat, Hadbin and Sharbithat, following by an intensive survey along the whole coastline. It covers aspects of the ecology and dynamics of this fishery and presents information on the abalone distribution, abundance, morphometry and size composition structures, habitat, competitors, predators, commercial production and marketing, biochemical composition, environment parameters, preservation, genetics, biology including growth, reproduction, spawning season, sex distribution, maturity stages and size at first maturity. The fishery is restricted to the southern coastline, which is strongly influenced by the monsoon winds, which result in major changes in the environmental conditions and the upwelling of deep-cold nutrient-rich water. This could regulate the limited distribution of this fishery between Ras Mirbat and Suqrah. They occurred at more exposed shores at depths up to 20 m, but most of the populations are found between 5-10 m. Abalone habitats were mostly destroyed and showed signs of degradation in algal cover. Sea urchin is the main competitor present at 25 times the number of abalone. Sea star also abundant and shows sign of predation on abalone. Abalone population density was 0.07 individuals/m², which is inadequate to support a good reproductive level and maintain a sustainable fishery. The remaining stock was calculated at 707000 pieces (54.5 t of flesh wet weight). This fishery is regulated through a fishing season for two months a year combined with a MLS of 90 mm SL, but 50% of the divers catch is below this limit. Most of remain populations are of small and medium sizes. In addition, females are larger than males resulting in fishing selectivity; therefore, fewer females remain in the population, which has an impact on reproduction and recruitment. The species sexually matured at sizes over 60 mm SL. Spawning occurs from November to March/April at all the three sites. Growth is faster in the first year and decrease with age. Fishing mortality is high and egg production very low. Populations of Haliotis mariae found in all the three study areas of Oman were genetically linked. The H mariae stock is considered seriously compromised and the remaining population seems unsustainable under current fishing pressure combined by environment destruction and other biological failures. Reduction of exploitation rate by 50%, increasing the size at capture, relocating the fishing season, adequate monitoring, controlling and surveillance with strong enforcement of existing legislation are necessary to conserve and protect the fishery. The resource user groups need to be involved in management process of this fishery and education programmes and awareness campaign should be introduced to highlight the need for divers to change attitudes and practices to make the fishery more sustainable. Research and further studies on more aspects of this fishery are recommended.
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Ngo, Le Phuong. "Leveraging cell micropatterning technology for rapid cell-based assessment of chemical toxicity and population variation in toxicity susceptibility". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115754.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references.
With the advent of combinatorial chemistry, the number of novel synthetic chemicals has skyrocketed over the past three decades, bringing about tremendous advances in medicine and material science. At the same time, the massive libraries of existing chemicals coupled with the unprecedented rate of new chemical generation presents a unique and costly challenge to toxicity testing in the 21 st century. In recent years, the United States has seen large coordinated efforts across governmental agencies to shift from expensive and slow traditional in vivo tests to more affordable and higher throughput in vitro methods. For each human cell, about 100,000 DNA lesions occur every day. Unrepaired DNA damage can lead to deleterious health consequences, including cancer and aging. Therefore, an essential endpoint in cell-based chemical safety testing is the assessment of a compound's genotoxic potential. In this work, we developed a CometChip platform that addresses two major areas that are lacking in genotoxicity testing: 1. rapid and sensitive detection of bulky DNA adducts, and 2. robust and physiologically relevant metabolism of test compounds. The assay uses two DNA repair synthesis inhibitors, hydroxyurea and I-[beta]-D-arabinofuranosyl cytosine, to cause strand-break accumulation and HepaRGTM cells to provide high levels of liver-specific functions. We also conducted extensive validation studies and a small chemical screen to demonstrate the platform's applicability in genotoxicity testing. One of the most important decisions of proliferating cells under stresses is to divide, senesce, or die. Therefore, in vitro measurements of cell survival after a toxic exposure are among the most fundamental and broadly used endpoints in biology. The gold standard for cell survival testing is the colony forming assay, which is exquisitely sensitive but sees limited uses due its low-throughput nature and requirement of large dishes. We have developed MicroColonyChip as a high-throughput platform that can directly measure a cell's ability to divide and has the potential to provide highly sensitive and rapid toxicity assessment of chemicals of interest. The technology is based on the use of a microcolony array where the size distributions for different conditions provide a direct measure of cell survival. We have results showing that MicroColonyChip is as sensitive as the gold standard assay, reduces ~80% incubation time, and requires ~250x less surface area for cell growth. In addition to detecting genotoxic agents, it is also important to understand how an individual responds to internal and external assaults to DNA as a necessary first step for assessment of human health outcomes. There is a high variability in DNA repair capacity among people, and more studies are needed to elucidate whether a causal relationship between DNA repair capacity and clinical outcomes exists. We applied CometChip to study repair kinetics in human primary lymphocytes. In order to account for the extensive crosstalk and competition between different repair pathways, repair of different types of DNA damage was measured. To test the assay's sensitivity and reproducibility, a small population of 56 healthy volunteers were recruited to give blood samples. Isolated lymphocytes from different individuals show significant differences in repair kinetics of oxidative damage and a sevenfold variation in repair rates. Taken together, the work described here represents significant technological advances in addressing a number of major challenges in chemical toxicity testing as well as in the evaluation of health outcome variability across populations. The technologies also open doors to exciting opportunities in personalized strategies for disease prevention and intervention.
by Le Phuong Ngo.
Ph. D.
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Diadoo, Cindy A. "An assessment for the need of a bioterrorism plan at hospital XYZ in Minnesota". Online version, 1999. http://www.uwstout.edu/lib/thesis/1999/1999diadoo.pdf.
Testo completo
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Ge, Jing Ph D. Massachusetts Institute of Technology. "Engineering a comet-based platform for specific, sensitive, and high throughput assessment of multiple DNA repair pathways in humans". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99054.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references.
Human exposure to dangerous genotoxins is unavoidable, as DNA damaging agents are ubiquitous both in our environment and within our cells. The diversity in lesions induced by these agents led to the evolution of several DNA repair pathways that suppress the mutagenic and toxic effects of DNA damage. Ironically, many cancer chemotherapeutics are themselves genotoxic due to their ability to target tumor cells that are more vulnerable to DNA damage. Therefore, knowledge about DNA damage and repair is relevant to cancer prevention, susceptibility and treatment. Despite its fundamental importance, measurement of DNA damage and repair in people is far from routine, primarily due to technological obstacles. Recently, we have developed the CometChip, a novel platform for measuring DNA damage that has its basis in the well-accepted comet assay. To advance the CometChip for broader utility in screens and population studies, we further improved the platform to provide greater sensitivity, reproducibility and throughput. We then characterized the conditions of the CometChip to analyze different DNA repair pathways. We showed that the CometChip is effective for evaluating repair kinetics and for detecting deficiencies of base excision repair, nucleotide excision repair, mismatch repair, and non-homologous end-joining. The ability to assess multiple repair pathways opens door to many applications. In terms of basic research, we applied the CometChip technology to perform cross-pathway analysis of two repair proteins, Xrccl and DNA-PKcs. Results confirm known activities as well as reveal new cross-pathway functions of these proteins. In terms of clinical relevance, we used the CometChip to evaluate small molecule inhibitors of DNA repair proteins, which are potential chemotherapeutics. In terms of public health, we exploited the CometChip to learn about differences in DNA repair among individuals. We discovered that there are subpopulations of people who share similar BER characteristics and there are shared factors between BER and NER among individuals. Taken together, the CometChip platform represents a significant technological advance. From integrated analysis of repair proteins, to evaluation of clinically relevant chemicals, to studies of inter-individual variations, the CometChip has demonstrated value in uncovering new information about DNA repair in humans.
by Jing Ge.
Ph. D.
39
Poppendieck, Wigand. "Double integrating spheres: A method for assessment of optical properties of biological tissues". Thesis, Linköping University, Department of Biomedical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2701.
Testo completoAbstract (sommario):
The determination of the optical properties of biological tissue is an important issue in laser medicine. The optical properties define the tissue´s absorption and scattering behaviour, and can be expressed by quantities such as the albedo, the optical thickness and the anisotropy coefficient. During this project, a measurement system for the determination of the optical properties was built up. The system consists of a double integrating sphere set-up to perform the necessary reflection and transmission measurements, and a computer algorithm to calculate the optical properties from the measured data. This algorithm is called Inverse Adding Doubling method, and is based on a one-dimensional transport model. First measurements were conducted with the system, including measurements with phantom media (Intralipid-ink solutions) and with cartilage samples taken from the human knee joint. This work also includes an investigation about the preparation of tissue samples for optical measurements.
40
Charrois, Jeffrey William Adrien. "Biological and chemical assessment of three weathered creosote contaminated soils, an ecotoxicological approach". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34344.pdf.
Testo completo
41
Kaaya, Lulu Tunu. "Biological assessment of tropical riverine systems using aquatic macroinvertebrates in Tanzania, East Africa". Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/8802.
Testo completoAbstract (sommario):
Includes bibliographical references.In Tanzania, and in East Africa in general, bioassessment methods for monitoring and assessing riverine ecosystems are not yet in place. This thesis describes the development of a macroinvertebrate-based bioassessment method for assessing the degree of anthropogenic disturbance in Tanzanian rivers. The hypotheses that, 'macroinvertebrate assemblages reflect disturbance in river systems'; 'rivers with similar abiotic features have similar macroinvertebrate assemblages'; and 'spatio-temporal variation in macroinvertebrate assemblages influence bioassessment', are tested. Macroinvertebrate and environmental data were collected from the Pangani, Rufiji and Wami-Ruvu basins. Univariate analyses; constrained and un-constrained ordinations and a linear response model were used to test the hypotheses. Five important bioassessment aspects were investigated. A set of 20 criteria for screening reference sites was established and used to identify and distinguish between reference and test sites in the study area. A two-level hierarchical framework for classifying homogenous river types was developed and validated. Three river types were classified: Pangani highland uplands, central eastern Africa uplands and central eastern Africa lowlands, each with two sub-Groups. A macroinvertebrate-based biotic index, the Tanzanian River Scoring System (TARISS), was established for monitoring and assessing anthropogenically induced disturbance in Tanzanian rivers. TARISS has three metrics; number of taxa, TARISS score and average score per taxon (ASPT) for measuring disturbance. Spatio-temporal variations in macroinvertebrate taxa, assemblages and TARISS metrics were examined. Spatial variation within river types was driven by catchment characteristics such as geographical location, geology, altitude and local characteristics such as active channel width, proportions of boulder, cobble and sand on the bottom, influenced reference conditions in all three river types. Temporal variations were significant in the central eastern Africa lowlands, with higher TARISS metrics in wet than in dry periods. Biological and physico-chemical reference conditions were identified for each river type and sub-Group. Guidelines for interpreting TARISS data were established for the validated sub-Groups. In conclusion, TARISS proven to be reliable in detecting anthropogenic disturbance in Tanzanian rivers and is recommended as a national bioassessment method.
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McClafferty, Julie A. "An Assessment of the Biological and Socioeconomic Feasibility of Elk Restoration in Virginia". Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/31295.
Testo completoAbstract (sommario):
The biological and socioeconomic feasibility of restoring elk (Cervus elaphus) to Virginia was assessed. Biological feasibility was determined by evaluating habitat suitability for elk while considering potential impacts of elk on existing fauna and flora in Virginia. Suitability was assessed by creating a habitat suitability index (HSI) model that measured the availability and accessibility of open foraging areas and forested cover areas, the availability of permanent water sources, and the degree of fragmentation by roads. Eight areas were identified as potential elk habitat: 1 in Southwest Virginia, 4 in the Shenandoah Mountains (Shenandoah, Highland, Big Meadows, Peaks of Otter), and 3 in the Southern Piedmont (Danville, Brookneal, Rehobeth). The highest potentials for supporting an elk herd were found in the Highland and Big Meadows study areas, medium biological feasibilities were found in the Southwest, Shenandoah, and Brookneal study areas, and low biological feasibilities were found in the Peaks of Otter, Danville, and Rehobeth study areas. A restored elk herd could negatively affect indigenous fauna and flora by changing the structure and diversity of existing forested ecosystems, but impacts can be minimized by maintaining elk populations at or below cultural carrying capacity. The introduction of diseases during restoration and possible transmission of those diseases from elk to humans, livestock, and other wildlife also are concerns, but these issues can be addressed by following a risk minimization protocol.
Socioeconomic feasibility was assessed with a statewide mail survey of Virginia residents, 4 regional stakeholder workshops, an analysis of economic costs and benefits associated with elk restoration, and an assessment of the risks of elk-human conflicts in each of the 8 study areas. Overall, most (61%) respondents agreed that elk restoration would be good for Virginia. However, the low response rate (30%) and low confidence among respondents (49%) in their knowledge about elk indicated that most residents do not have the interest and/or necessary information to form a definitive opinion. Residents believe that the greatest benefits of restoration would be the value-based and indirect ecological benefits, such as returning an extirpated species to its native range, whereas the greatest perceived costs were the economic impacts to property, crop depredation, and public safety hazards. In contrast, local stakeholder representatives identified economic returns from increased tourism due to the presence of elk and the creation of new recreational opportunities as the most anticipated benefits; important concerns were the potential for property damage by elk, the potential impacts on local ecosystems, and the costs of implementing and administering an elk restoration program and subsequent elk management. Proposed resolutions for these issues varied by region. Representatives from the Southwest and northern Shenandoah Mountain (Shenandoah and Big Meadows study site) Regions preferred not to restore elk, whereas those from the southern Shenandoah Mountain (Highland and Peaks of Otter study site) and the Southern Piedmont Regions preferred to start out small with a carefully controlled and monitored â experimentalâ population.
Economic benefits of elk restoration, as determined through analysis of data from other eastern states currently managing elk populations, are associated with tourism and the revenues brought to the community during elk hunting seasons, whereas economic costs are associated with crop damage, elk-vehicle collisions, and the administrative costs of managing an elk herd. Although the initial costs of transporting, releasing, and monitoring a founder population likely will exceed immediate benefits, once an elk population is established, benefits likely will exceed costs. However, an equitable distribution of costs and benefits must be devised so that the individuals who bear the costs are afforded a comparable or greater set of benefits.
Risk of landowner elk-conflicts was examined by comparing human population densities and growth rates, percent private versus public land, and agricultural trends across the 8 study areas. Highest risk for elk-human conflicts was identified in the Southern Piedmont Region and in the Shenandoah study site, risk was moderate in the Southwest, Big Meadows, and Peaks of Otter study sites, and risk in the Highland study site was low.
Overall, the Highland study site had the highest feasibility for elk restoration of all study areas examined; the Big Meadows and Southwest study sites both demonstrated moderate feasibility. Restoration in these areas is possible so long as management objectives remain flexible, plans are made in advance to address potential concerns, and the public is involved in the decision-making processes both before and after elk are released.
Master of Science
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Bundy, J. G. "The use of biological methods for the assessment of oil contamination and bioremediation". Thesis, University of Aberdeen, 1999. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602050.
Testo completoAbstract (sommario):
There is a concern that concentration-based targets for soil clean-up are arbitrary, and do not necessarily relate to the environmental threat posed by the residual contamination. The development of sensitive, reliable, and ecologically relevant biological tests for oil-polluted soils would address these problems, and form a valuable complement to chemical analysis. Three biological test systems were chosen for examining the impact of oil contamination on soil microbes: (1) lux-marked bacterial biosensors, (2) Biological carbon source utilization profiles, and (3) phospholipid fatty acid (PLFA) community profiles. This allowed the testing of effects at three different levels of ecological complexity: respectively, single species; culturable bacteria; and eubacteria and eukaryotes. The use of specific bioluminescent biosensors (i.e. with lux genes fused to promoters from hydrocarbon degradation pathways) allowed the rapid detection of different hydrocarbon classes. The bacterial biosensors were optimized for the assessment of hydrocarbon compounds. Development of quantitative structure-activity relationships (QSARs) increased understanding of their responses to hydrocarbons and other petroleum-derived compounds. The three biological methods were then used to monitor the nutrient-assisted bioremediation of oil-spiked soils in two separate microcosm experiments: (1) remediation of four crude oils and one refined oil compared using bacterial biosensors, and (2) effects of diesel on three different soil types, and effects of three refined oils on one soil type, assessed using Biolog and PLFA profiling. All three biological test methods were sensitive to the oil contamination levels applied in the microcosm experiments. Individual species (biosensor tests) gave different responses to different oils; however, the community-level responses showed no differences. The microbial communities of the three different soil types could still be distinguished after 14-15 weeks of hydrocarbon contamination. The community response of the contaminated soils had changed from that of the control soils after four weeks of bioremediation, and did not return in similarity to the control over the course of the experiment.
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Quinn, Terence J. "Improving outcome assessment for clinical trials in stroke". Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/1648/.
Testo completoAbstract (sommario):
Abstract Clinical trials are at the centre of advances in our understanding of stroke and its optimal treatment. In this thesis the uses and properties of outcome assessment scales for stroke trials are described, with particular attention given to the modified Rankin Scale (mRS). Through comprehensive literature review I will show that mRS is the most frequently used functional outcome scale in clinical trials but efficacy of the scale is potentially limited by inter-observer variability. Using a “mock” clinical trial design I demonstrate that inter-observer mRS variability in contemporary practice is moderate (k=0.57). Adding these data to systematic review of published data, confirms an overall moderate inter-observer variability across ten trials (k=0.46). Differing strategies to improve mRS reliability will then be described. I will outline development of a bespoke training package, international training scores across 2942 raters again confirms suboptimal reliability (k=0.67). A pilot trial using endpoint committee review of video recorded interviews demonstrates feasibility of this approach. Attempts to improve reliability by deriving mRS from data recorded in patients’ hospital records are not successful (k=0.34). In the final chapters I present a novel methodology for describing stroke outcomes – “home-time”. This measure shows good agreement with mRS, except at extremes of disability. Finally to put mRS in a historical context, the career of John Rankin and the development of his eponymous scale is recounted.
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Holden, Lindsay J. "Investigation of aspects of reactive gliosis in human astrocytoma cell lines : application for toxicity assessment". Thesis, Aston University, 2007. http://publications.aston.ac.uk/11066/.
Testo completoAbstract (sommario):
The process of astrogliosis, or reactive gliosis, is a typical response of astrocytes to a wide range of physical and chemical injuries. The up-regulation of the astrocyte specific glial fibrillary acidic protein (GFAP) is a hallmark of reactive gliosis and is widely used as a marker to identify the response. In order to develop a reliable, sensitive and high throughput astrocyte toxicity assay that is more relevant to the human response than existing animal cell based models, the U251-MG, U373-MG and CCF-STTG 1 human astrocytoma cell lines were investigated for their ability to exhibit reactive-like changes following exposure to ethanol, chloroquine diphosphate, trimethyltin chloride and acrylamide. Cytotoxicity analysis showed that the astrocytic cells were generally more resistant to the cytotoxic effects of the agents than the SH-SY5Y neuroblastoma cells. Retinoic acid induced differentiation of the SH-SY5Y line was also seen to confer some degree of resistance to toxicant exposure, particularly in the case of ethanol. Using a cell based ELISA for GFAP together with concurrent assays for metabolic activity and cell number, each of the three cell lines responded to toxicant exposure by an increase in GFAP immunoreactivity (GFAP-IR), or by increased metabolic activity. Ethanol, chloroquine diphosphate, trimethyltin chloride and bacterial lipopolysaccharide all induced either GFAP or MTT increases depending upon the cell line, dose and exposure time. Preliminary investigations of additional aspects of astrocytic injury indicated that IL-6, but not TNF-α. or nitric oxide, is released following exposure to each of the compounds, with the exception of acrylamide. It is clear that these human astrocytoma cell lines are capable of responding to toxicant exposure in a manner typical of reactive gliosis and are therefore a valuable cellular model in the assessment of in vitro neurotoxicity.
46
Li, Zhengrong. "Model-based Tests for Standards Evaluation and Biological Assessments". Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29108.
Testo completoAbstract (sommario):
Implementation of the Clean Water Act requires agencies to monitor aquatic sites on a regular basis and evaluate the quality of these sites. Sites are evaluated individually even though there may be numerous sites within a watershed. In some cases, sampling frequency is inadequate and the evaluation of site quality may have low reliability.
This dissertation evaluates testing procedures for determination of site quality based on modelbased procedures that allow for other sites to contribute information to the data from the test site. Test procedures are described for situations that involve multiple measurements from sites within a region and single measurements when stressor information is available or when covariates are used to account for individual site differences.
Tests based on analysis of variance methods are described for fixed effects and random effects models. The proposed model-based tests compare limits (tolerance limits or prediction limits) for the data with the known standard. When the sample size for the test site is small, using model-based tests improves the detection of impaired sites. The effects of sample size, heterogeneity of variance, and similarity between sites are discussed. Reference-based standards and corresponding evaluation of site quality are also considered. Regression-based tests provide methods for incorporating information from other sites when there is information on stressors or covariates.
Extension of some of the methods to multivariate biological observations and stressors is also discussed. Redundancy analysis is used as a graphical method for describing the relationship between biological metrics and stressors. A clustering method for finding stressor-response relationships is presented and illustrated using data from the Mid-Atlantic Highlands. Multivariate elliptical and univariate regions for assessment of site quality are discussed.Ph. D.
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Patke, Usha. "Inquiry-based laboratory investigations and student performance on standardized tests in biological science". ScholarWorks, 2011. https://scholarworks.waldenu.edu/dissertations/1089.
Testo completoAbstract (sommario):
Achievement data from the 3rd International Mathematics and Sciences Study and Program for International Student Assessment in science have indicated that Black students from economically disadvantaged families underachieve at alarming rates in comparison to White and economically advantaged peer groups. The study site was a predominately Black, urban school district experiencing underachievement. The purpose of this correlational study was to examine the relationship between students' use of inquiry-based laboratory investigations and their performance on the Biology End of Course Test, as well as to examine the relationship while partialling out the effects of student gender. Constructivist theory formed the theoretical foundation of the study. Students' perceived levels of experience with inquiry-based laboratory investigations were measured using the Laboratory Program Variable Inventory (LPVI) survey. LPVI scores of 256 students were correlated with test scores and were examined by student gender. The Pearson correlation coefficient revealed a small direct correlation between students' experience in inquiry-based laboratory investigation classes and standardized test scores on the Biology EOCT. A partial correlational analysis indicated that the correlation remained after controlling for gender. This study may prompt a change from teacher-centered to student-centered pedagogy at the local site in order to increase academic achievement for all students. The results of this study may also influence administrators and policy makers to initiate local, state, or nationwide curricular development. A change in curriculum may promote social change as students become more competent, and more able, to succeed in life beyond secondary school.
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Mussgnug, Robert Sebastian. "An assessment of the long-term changes in chondrichthyan abundance on the inshore trawl grounds of the Agulhas Bank, South Africa". Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/14017.
Testo completoAbstract (sommario):
Trawl fisheries have been operating in South African waters for roughly 110 years. In contrast to other trawl fisheries, the South African fishery was opened by government-funded scientific trawl surveys beginning in 1898. Detailed records of survey trawls undertaken immediately prior to and during the beginning of commercial trawling activity provided a rare opportunity to examine longterm changes in fish abundance. This dissertation focuses on the chondrichthyans, which are believed to be the group of fishes most at risk from intense exploitation. Despite some problems associated with changes in taxonomy and the efficiency of gear, this analysis was able to compare two distinct periods at three taxonomic levels: The periods were taken to represent baseline values prior to the opening of trawl fisheries and contemporary data, separated by roughly 80 years of intense, trawling activity. Three historically important trawl grounds were identified as having sufficient samples from each period. Between the surveys, trawl velocity did not deviate much from contemporary trawl velocities, although all surveys were found to have a significantly different velocity. In respect to the catch composition, significant changes were found in the relative abundance of the total catch composition, as a general shift from large, long-lived species towards smaller species was found. This applied both for teleosts as well as chondrichthyans, with the entire chondrichthyan catch composition showing a decrease, with the exception of Callorhinchus capensis, which increased significantly. Changes in chondrichthyan swept-area density were found to follow those trends found in the relative abundance: An increase was found in Callorhinchus capensis, whereas all other species decreased. All chondrichthyans were classed in low productivity categories and were assigned a high risk factor to overfishing. Reasons for the declines in the chondrichthyan assemblage were low fecundity, slow maturation and the inability due to these factors to adapt to an environment altered by trawling. Only in the case of Callorhinchus capensis were secondary effects of trawling such as the removal of competitor species likely to have caused the increase in relative abundance and swept area density as well as Callorhinchus capensis having a relatively high fecundity among chondrichthyans. In general, chondrichthyan decreases exceeded those of teleosts, and this work provides broad empirical support for the hypothesis that the low fecundity and slow growth of chondrichthyan species places this group at higher risk than teleosts.
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Schwartz, Joseph Howard. "Development and Application of an Assessment Protocol for Watershed Based Biomonitoring". Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc279219/.
Testo completoAbstract (sommario):
With numerous bioassessment methodologies available, a regional protocol needs to be developed to ensure that results are comparable. A regional assessment protocol was developed that includes collecting five benthic macroinvertebrate samples, identifying organisms to genus, and calculating the following metrics: Number of Taxa, Total Number of Individuals, Simpson's Diversity Index, Shannon's Diversity Index, Percent Contribution of Dominant Taxa, Hilsenhoffs Biotic Index, and Percent Contribution of Dipterans. Once the protocol was developed, it was used to assess the Bayou Chico
tributaries and watershed. All three tributaries had been significantly impacted by human activity as had the watershed as a whole. This study indicates that a regional protocol could be developed and is appropriate for biomonitoring at the watershed scale.
50
Mitchell, Joy Lynn. "Rapid toxicity assessment using esterase enzyme activity of several microalgal species". Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/24912.
Testo completo