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Dissertations / Theses on the topic 'Lead levels'

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Published: 10 December 2022
Last updated: 28 January 2023

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1

Manmee, Charuwan. "Lead levels in teeth as a measure of life-time lead exposure in children." Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/2177.

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Background and aims Lead exposure has irreversible health effects in children who are susceptible even at very low levels of exposure. The usual test for lead exposure is blood lead level (BLL), but this indicates only recent exposure. This study aimed to ascertain the suitability of milk teeth as biomarker of the history of lead exposure and to develop a methodology for this novel biomarker. Methods My study comprised three stages: Firstly, I explored potential determinants of dentine lead levels (DLLs) in children living in Newcastle upon Tyne (the Tooth Fairy Study). Secondly, I developed a methodology for assessing the history of early life lead exposure using dentine, and thirdly I applied my methodology to newly extracted teeth from children in Teesside. The Tooth Fairy study cohort consisted of 69 children aged 5-8 years. DLLs were measured in primary dentine using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). To identify determinants of early life exposure, a questionnaire was used. I assessed associations between lifestyle characteristics and DLLs. As teeth develop chronologically they offer the opportunity to study histories of exposure in detail. I collected two deciduous molars each from 15 children aged 6-8 years living in Northeast England. By combining high spatial resolution LA-ICP-MS with dental histology, I acquired information on the age specific concentrations of lead in dentine from in utero to several years after birth. Results Dentine lead levels in the Tooth Fairy cohort ranged from 0.06 to 0.77μg/g, median 0.21μg/g. Unlike other studies, I did not find significant associations between socio-economic status or other possible determinants and lead exposure. In developing the biomarker I found that the 100 micron ablation pit represented 42 days of dentine growth, enabling me to assign an age interval to each ablation pit. I found lead ratios in primary dentine to be consistent between teeth from the same child, and at the same age within each tooth. This indicated that the history of exposure can be determined using a single, multi-point ablation transect on high quality longitudinal sections of individual teeth. Conclusions  I found no association between socio-economic status and dentine lead levels in a cohort of children from Newcastle upon Tyne.  I developed a novel technique to date ablation points in dentine in milk teeth, and, using this technique have demonstrated that primary dentine is a potential biomarker for characterising the early life history of lead exposure in children.
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2

Luke, Colin G. "A study of factors associated with trends in blood lead levels in Port Pirie children exposed to home-based interventions /." Title page, contents and abstract only, 1991. http://web4.library.adelaide.edu.au/theses/09MPM/09mpml954.pdf.

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3

Mbongwe, Bontle. "Developing a clinical assessment tool for screening lead exposure levels during pregnancy and after delivery." Thesis, University of Pretoria, 2013. http://hdl.handle.net/2263/25722.

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Lead is a toxic heavy metal associated with adverse health effects ranging from developmental neurotoxicity to reproductive effects. While lead affects people of all ages, infants and children are the most vulnerable and susceptible to the neuro-developmental effects of lead exposure. Maternal blood lead concentrations that do not produce clinical toxicity on pregnant women have been linked to adverse offspring development. Observed reproductive effects to low lead levels during pregnancy include the risk of spontaneous abortions, effects on birth weight and preterm birth. There are particular concerns with regard to reductions in IQ scores. Research evidence suggests that an incremental increase in blood lead levels of 1 µg/dL is associated with approximately 1 IQ point deficit. Of particular concern is that currently no threshold has been observed or exists for developmental neurotoxicity to the chronic low lead exposures levels. While the developed countries have built evidence for lead exposure sources, have identified the most vulnerable groups to lead exposure, and have instituted control actions for lead exposure, it is not the case in developing countries such as Botswana. Currently, there is very little knowledge about the potential sources of lead exposure among different population groups not only in Botswana but also in most developing nations. There is also an evident limited knowledge on the behaviours and practices of different population groups that could potentially expose them to lead in developing countries. This thesis explores the following questions: i) Are there specific risk behaviours and practices peculiar to pregnant women in Botswana that could potentially expose them to lead? ii) What are the environmental lead concentration levels and their potential to expose pregnant women? iii)What are the blood lead concentrations at each stage of pregnancy and after delivery in Botswana and, iv) Can we use the information from these three questions to predict lead exposure levels during pregnancy and after delivery? v) Can we use the new information to a develop a policy dissemination brief to inform policy on lead exposure sources in Botswana, develop guidelines for health professionals for assessing and screening lead exposure levels during pregnancy and after delivery, develop an awareness leaflet for lead education? To address the specific risk behaviour and practices of pregnant women, a comprehensive validated risk assessment questionnaire was administered among 142 pregnant women during the first trimester of pregnancy (defined as 8-12 weeks) in four villages of different geographical settings and nomenclature (small/rural, major and semi urban). For purposes of this work the validation process involved obtaining information (from experts in the field and communities) relevant to the purposes of the study and to confirm that the tools employed for collection of data in all trimesters were suitable in terms of both construct and content. Data was collected between September 2009 and February 2010. To address potential environmental sources of lead exposure during pregnancy soil (n=28), water (n=28) and traditional cosmetic clay - letsoku (n=3) samples were collected in November 2010, February 2011 and May 2011 from the homes and in the vicinity of the study population to determine lead concentrations. To know baseline blood lead levels at each stage of pregnancy, blood samples were collected from September 2009 to February 2011 from pregnant women between weeks 8-12 (first trimester, n=137), 20-24 (second trimester n=126) and weeks 34-36 (third trimester n=106). Blood lead levels of women who completed the entire study from trimester on until after delivery (n=63) were then used to construct blood lead prediction models using statistical models. Pregnant women in the study area ingested non-food items such as soil, match sticks, pencil, chalk and animal feed such as bone meal (86%). Women applied used and unused car oils (in particular brake fluid) and other harmful substances for “treatment of skin conditions and for beautification purposes (74%). Older women (defined as 35 years in this study) were at a significantly higher risk to ingest soils (p<0.01). Mean (±SEM) lead concentrations in water exceeded the WHO drinking water quality standards nineteen fold (0.19±0.019 ppm (n=28) Major villages, had significantly higher Pb concentrations (p<0.05) in soils and water compared to small villages. Mean blood lead levels (±SEM) for the first, second and third trimesters were 1.96(±0.14)µg/dL, 2.49(±0.17) µg/dL, 2.66(±0.19) µg/dL respectively. Blood lead levels increases from the first to third trimester ranged from 1.6-5%. Blood lead concentrations significantly differed among locations (p<0.01). The highest concentrations were observed in women from smaller villages that were poorer (p<0.02). Pica, multiple risk behaviours/practices (engaging in two or more risk behaviours/practices), trimester of pregnancy, poor food supplementation and diet were predictors of blood lead levels ≥ 2µg/dL. There was a dose response relationship between supplement intake and an increase in blood lead levels. These findings suggest that pregnant women and their unborn babies could potentially be exposed to lead because of the environment in which they live, their economic status, lifestyle, behaviors and practices. Drinking water is a potential threat for lead exposure, not only among pregnant women, but other vulnerable groups such as infants and children. This study is the first in Botswana and one of the few in Africa to investigate lead exposure sources at each stage of pregnancy and after delivery. It is also the first to identify new potential lead exposure behaviors and practices such as the application of auto oils by pregnant women for treatment of skin diseases. The findings suggest the need to train health workers and equip them with the skills and knowledge to assess and screen women who could potentially be exposed to lead. Further, pregnant women need to be sensitized on potential lead exposure sources, to prevent lead poisoning. This study has been able to use the results to develop a policy brief for disseminating the results to decision makers, guidelines for utilization by health workers to screen lead exposure levels and an awareness leaflet for pregnant women. These have been validated and pretested at community and Government levels.
Thesis (PhD)--University of Pretoria, 2013.
School of Health Systems and Public Health (SHSPH)
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4

Stevenson, Amy L. "Lead levels and sources of exposure in migratory game birds after the implementation of lead-free shot in Canada." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79137.

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In Canada, regulations against the use of lead (Pb) shot for waterfowl hunting were first established in the early 1990s with the creation of a few non-toxic shot zones, and culminated with a national ban in 1997. Prior to establishment of the first non-toxic shot zones in Canada, a nation-wide survey of Pb accumulation in wing bones of young-of-the-year (YY) dabbling and diving ducks determined the incidence of elevated Pb exposure in different parts of the country (Scheuhammer & Dickson, 1996). The objective of the present study was to determine the incidence of elevated Pb accumulation in the same species several years after the national ban on Pb shot; to survey waterfowl hunters to determine approximate levels of compliance with the Pb shot ban; and to use stable Pb isotope analysis to help determine the relative importance of different sources of Pb exposure.
Wing bones from 721 YY black, mallard, and ring necked ducks, and 579 YY woodcock from selected zones in Ontario, Quebec, BC, and the Maritimes, Canada were analyzed for Pb using flame atomic absorption spectrometry. (Abstract shortened by UMI.)
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Consoir, Linda [Verfasser]. "Blood Lead Levels of the Southern Ghanaian Population : Ghana: Elaboration of Reference Values for Lead in Blood / Linda Consoir." Düren : Shaker, 2021. http://d-nb.info/1233548352/34.

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6

Kadakia, Rachna P. "The effect of window repairs and window replacement on lead dust levels." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12130.

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Thesis (M.A.)--Boston University
BACKGROUND: Lead dust in homes is the primary route of lead ingestion for children. More and more evidence concludes that levels of lead <10 !g/dl, which once was thought to be safe, can cause permanant neurological effects and damage. Lead exposure and toxicity is hard to treat because of the negative side effects of the chelating agents. The focus should be on prevention. OBJECTIVE: Our objective was to conduct a study to see if window replacements and/or window repairs will significantly decrease the lead levels in low income housing homes. This study is collaboration between HUD, weatherization groups, and public health departments. DESIGN/METHODS: We performed statistical analyses of lead loading result data that was collected on the field. Compared the lead loading results for each sample location in each unit before and after window repair (Cohort 2), window replacement (Cohort 1), and no treatment for the control group (Cohort 3). The analyses were completed using a two sample matched pair z test and a significance level of 0.05. The control group was used to measure variance and to see if the difference is statistically significant. RESULTS: There appears to be a statistically significant reduction in the mean loading results in the Window Repair Cohort 2 across both Phase 1 to 2 (z=-2.63) and Phase 1 to 3 (z= -3.10). There was not a statitistically significant reduction in the mean loading result of the samples in the Window Replacement Cohort 1 across Phase 1 to 3 (z=-1.3), and there surprisingly appears to be an increase in mean loading result of the samples across Phase 1 to Phase 2 (z= 1.65). There was a significant decrease in loading results throughout Phase 1 to 2 and Phase 1 to 3 for the Control Group Cohort 3. CONCLUSIONS: There is sufficient evidence to suggest that window repair will decrease lead dust levels in homes. According to our preliminary results window replacement decreases the average lead loading results by 43.6%, while window repairs decreased the average lead loading result by 97.4%. While this supports our hypothesis, the increase in lead loading results after a short time window replacement is unexpected. Further studies should be implemented to prevent high lead levels directly after weatherization and provide regulations.
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Ethington, Robert A. "Learning to lead modifying members' psychological and job readiness levels to lead new and existing ministries through situational leadership training /." Theological Research Exchange Network (TREN), 1992. http://www.tren.com.

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8

Nsheiwat, Zein. "Blood and hair lead levels in highly exposed populations in Israel and Jordan : lead smelter and battery factory as hot spots /." [Sede-Boker] : Ben-Gurion University of the Negev, 2007. http://aranne5.lib.ad.bgu.ac.il/others/NsheiwatZein.pdf.

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9

McLaine, Patricia Louise. "The Association between Elevated Blood Lead Levels and Reading Readiness in Kindergarten Children." Thesis, The Johns Hopkins University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3579521.

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Background and Objective: Lead exposure effects on IQ are well known, and detrimental impact of lead exposure on reading, math and school progress have been described. We evaluated the relationship between blood lead levels (BLLs) and kindergarten reading readiness in a diverse urban school population.

Methods: School administrative data and Phonological Awareness and Literacy Screening Kindergarten (PALS-K) test scores, measures of kindergarten reading readiness, for children attending public school kindergarten in Providence, Rhode Island were linked to Department of Health BLLs. Children with at least one BLL and reading readiness scores in both the fall and spring were included in the study (N=3,406). Fifty-nine percent (59%) were Hispanic. Data were analyzed using multiple linear and logistic regression with progressive levels of adjustment.

Results: The median geometric mean (GM) BLL was 4.2 (IQR 2.9-6.0)μg/dL. In the fall, children whose BLLs were 5-9 and ≥10μg/dL were 1.44 and 2.51 times more likely to fail to achieve fall benchmark for reading readiness [OR 1.44 (95%CI 1.23, 1.69) and OR 2.51 (95%CI 1.86, 3.40)] compared to children whose BLLs were 0-4μg/dL. Fall reading readiness scores were decreased by 4.5 and 10 points for children with BLLs in the 5-9 and 10+μg/dL categories, respectively, compared to children with BLLs 0-4μg/dL [-4.5 points (95%CI -6.2, -2.9) and -10.1 points (95%CI -13.3, -7.0)]. In the spring, children who had scored below the fall benchmark and who had GM BLLs ≥5μg/dL were approximately 1.5 times more likely to fail to achieve the benchmark compared to children with BLLs <5μg/dL. For children who achieved the fall benchmark, BLLs were not associated with an increased risk of failure in the spring.

Conclusions: Children who enter kindergarten with low levels of reading readiness and GM BLLs of >5μg/dL are at increased risk for failure to make adequate progress.

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Walker, Scott. "Does Cultural Heterogeneity Lead to Lower Levels of Regime Respect for Basic Human Rights?" Thesis, University of North Texas, 2002. https://digital.library.unt.edu/ark:/67531/metadc3303/.

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This dissertation is a cross-national investigation of the relationship between cultural heterogeneity and regimes' respect for basic human rights. The quantitative human rights literature has not yet addressed the question of whether high levels of cultural diversity are beneficial or harmful. My research addresses this gap. I address the debate between those who argue that diversity is negatively related to basic human rights protection and those who argue it is likely to improve respect for these rights. Ultimately, I propose that regimes in diverse countries will be less likely to provide an adequate level of subsistence (otherwise known as basic human needs) and security rights (also known as integrity of the person rights) to their citizens than regimes in more homogeneous countries. Using a data set of 106 non-OECD countries for the years 1983 and 1993, I employ bivariate, linear multivariate regression, and causal modeling techniques to test whether higher levels of ethnolinguistic and religious diversity are associated with less regime respect for subsistence and security rights. The analysis reveals that higher levels of cultural diversity do appear to lead to lower respect for subsistence rights. However, counter to the hypothesized relationship, high levels of diversity appear to be compatible with high levels of respect for security rights.
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Laing, Nicola. "The effect of lead communication pipe replacement on lead levels in low alkalinity drinking water and the analysis of corrosion products formed in pipes." Thesis, University of Strathclyde, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423880.

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Cummins, Robert. "Analysis of Soil Lead Levels in an Historic District of a South Central Kentucky City." TopSCHOLAR®, 2003. http://digitalcommons.wku.edu/theses/588.

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Lead in soil has been shown to be a significant pathway of lead exposure in children. Several factors including age of housing units, exterior composition, and paint loading may affect the amount of lead present in the soil. The purpose of this study was to analyze soil lead levels on properties located in an historic district and relate those levels to the variables previously mentioned. A total of 30 soil samples were collected from housing units in a nationally recognized historic district. Concentrations of lead in the soil were analyzed using a NITON X-ray Fluorescence Spectrum Analyzer, following EPA Method 6200 and the instrument protocol. Significant differences were found between the soil lead levels and paint loading (fully painted vs. non-painted). Significant differences were also found between soil lead levels and exterior surface (frame, brick, and other). A correlation analysis revealed there was no correlation between housing age and soil lead levels. Soil lead can be used as a predictor of blood lead levels in children. Using the information regarding soil lead concentration, the relative risk of exposure to lead and the subsequent health effects can be estimated for children living in the study area. The results from this study can also be used to initiate other studies and develop educational strategies for the district.
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Smith, Marjorie Ann. "The effects of low levels of environmental lead on children : the relevance of social factors." Thesis, University College London (University of London), 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445343.

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Sombers, Leslie A. "Determination of Trace Levels of Lead in Whole Blood by Graphite Furnace Atomic Absorption Spectroscopy." W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539626166.

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CHEN, CHIN KWANG. "AN EVALUATION OF THE INFLUENCE OF ADJACENT ACTIVITIES ON THE AIR LEAD CONCENTRATION DURING LEAD ABATEMENT TASKS AND AN EVALUATION OF LEVELS OF LEAD IN PAINT IN EXISTING HOUSING AND IN NEW PAINTS IN SINGAPORE." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1099534543.

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Peñuela, Norma. "The relationship between dietary intake and blood lead levels among WIC infants in rural West Virginia." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=2897.

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Thesis (M.S.)--West Virginia University, 2003.
Title from document title page. Document formatted into pages; contains vii, 56 p. Vita. Includes abstract. Includes bibliographical references (p. 41-45).
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Berggren, Andreas. "Ficedula hypoleuca hemoglobin levels in lead contaminated areas. : Is bird health affected by invertebrate community composition and abundance?" Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-152600.

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Mining is a widespread industrial activity that in many cases, via mining wastes, leads to altered concentrations of metals in close vicinity to the mining activities. Metals in mining waste can have high toxicity and may persist in environments for long time periods. The presence of metals, such as lead (Pb), is known to contaminate and cause damage to nearby organisms and ecosystems. Birds are at risk of metal contamination and, since they are predators high up in the food chain, may face accumulation of metal in tissue over time, via consumption of contaminated prey. Small passerine species, such as the pied flycatcher (Ficedula hypoleuca), are suitable for studying metal contamination as they are ubiqutious, and high up in the food chain. Pied flycatchers feed exclusively on invertebrates, making the abundance, quality, and potential contamination of invertebrates interesting to study with regard to the health of the birds. Studies have shown that hemoglobin (Hb) levels in young pied flycatchers are reduced by high background levels of Pb.  This may be linked to prey availability and quality, as invertebrates are known to alter their composition, and contain higher Pb concentrations in Pb contaminated areas. Here, I investigated how invertebrate abundance and community composition, and pied flycatcher Hb concentrations (i.e. health), in reference and Pb contaminated areas, were related to each other. Invertebrate traps were set and sampled twice during the summer of 2018 to provide invertebrate data to the study. Bird Hb levels was acquired by taking blood samples from nearly fledged chicks in birdhouses placed in the different areas. I found a potential trend towards higher Hb levels in reference areas (p=0.110), suggesting that bird health is reduced by the presence of Pb, but this could not be explained by differences in invertebrate community composition or abundance (p>0.05). Hence, based on this study, high Pb concentrations in the soil does not directly, or indirectly via potential impacts on the prey community composition, influence the health of pied flycatchers.
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Alexandra, Markovic Markovic, and Edforss Arvid. "An evaluation of current calculations for safety stock levels." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Maskinteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-36505.

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Abbey, James Duane. "Analyzing impacts on backorders and ending inventory in MRP due to changes in lead-time, demand variability and safety stock levels." [Ames, Iowa : Iowa State University], 2008.

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Griffin, Jeffrey Cliff. "Decay of mass-separated [superscript]195Bi to levels in [superscript]195Pb : collinear laser spectroscopy on mass-separated neutron-deficient lead isotopes." Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/27319.

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Etchevers, Anne. "Exposition au plomb des enfants en France : déterminants et dépistage." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1B022.

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Les jeunes enfants sont les plus exposés au plomb et les plus sensibles à ses effets sur la santé, notamment sur le développement. Une enquête d’imprégnation sur 3831 enfants vivant en France a permis d’établir la moyenne géométrique des expositions au plomb à 14,9 (+/- 0,5) µg/L de sang avec 76000 enfants au-delà du seuil d’intervention obligatoire de 50µg/L. Les critères actuels de dépistage se sont avérés peu aptes à repérer ces enfants surexposés et de nouveaux critères sont proposés. En complément, une enquête environnementale avec mesures de plomb dans le logement a été réalisée dans 484 logements. Les poussières au sol des habitations et l’eau du robinet sont des facteurs important de surexposition, ainsi que l’utilisation de vaisselle et cosmétiques traditionnels. Les politiques de prévention doivent être poursuivies compte tenu de la persistance de sources d’exposition et de la toxicité même à faible dose
Young children are most exposed to lead and the most susceptible to its health effects, notably on development. A nationwide representative survey on 3831 children in France has established the geometric mean of lead exposures at 14.9 (+/- 0.5) µg/L of blood with 76000 children beyond the mandatory action level of 50μg / L. The current screening criteria have proved insufficient to identify these overexposed children and new ones are proposed. In addition, an environmental investigation with lead measurements in housing was performed in 484 homes. Household floor dust and tap water are major factors of overexposure, and also the use of traditional dishes and cosmetics. Prevention policies must be pursued in light of the continuing sources of exposure and toxicity even at low doses
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Imhoff, Paul W. "Servant Leadership and Collective Teacher Efficacy: Do higher levels of servant leadership behaviors in elementary principals lead to increased collective teacher efficacy?" Miami University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=miami1531819909906669.

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Gonzalez, Gabriel. "Alterations in Fatty Acid Amide Hydrolase (Faah) Transcript Levels and Activity Lead to Changes in the Abiotic Stress Susceptibility of Arabidopsis Thaliana." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115085/.

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N-Acylethanolamines (NAEs) are a class of bioactive lipids, and FAAH is one of the enzymes responsible for degrading NAEs in both plants and animals. in plants, FAAH appears to be closely associated with ABA, a phytohormone which has long been associated with plant stress responses, since the overexpression of FAAH in Arabidopsis results in ABA hypersensitivity. Therefore, it is reasonable to speculate that alterations in FAAH transcript levels will result in altered stress responses in plants. to investigate this hypothesis experiments were carried out in which wild type (WT), FAAH-overexpressing (OE), and T-DNA insertional FAAH knockouts of Arabidopsis (faah) were grown in MS media under stress conditions. the stress conditions tested included chilling stress, heavy metal stress induced by cadmium or copper, nutrient limitations induced by low phosphorus or low nitrogen, salt stress induced with NaCl, and osmotic stress induced with mannitol. the OE plants were consistently hypersensitive to all stress conditions in relation to wild type plants. Inactive FAAH overexpressors did not have the hypersensitivity to the salt and osmotic stress of the active OE plants and were instead tolerant to these stresses. FAAH2 (faah2) knockouts and FAAH 1 and 2 double knockouts (faah 1+2) were based on some root development parameters somewhat more tolerant than WT plants, but more sensitive in terms of shoot growth. Collectively the data suggests that FAAH activity may interact with stress-responsive pathways in plants, perhaps including pathways involving ABA.
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Boddu, Arathi. "A procedure to evaluate the costs and benefits of managing staffing levels in an order picking operation." Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1155309515.

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Merkley, Brett J. "Sources and Pathways of Lead Contamination in Urban Community Gardens in Toledo, Ohio." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1555621213052896.

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Cann, Kevin John. "An investigation into the existence of highly-deformed states in '2'2'2Th using the electron detector array SACRED." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367087.

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Allatt, Roger Giles. "Fine structure in the alpha decay of '1'9'2Po : shape coexistence in '1'8'8Pb." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367136.

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Meneray, Jennifer. "Coming Out| When Micro Level Vulnerabilities lead to Macro Level Risk." Thesis, The George Washington University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10822934.

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Exploratory projects have the capability to emerge new ways of understanding data. Non-traditional perspectives, like the intersectional-vulnerability standpoint used in this project, enable researchers to step back and look at experiences differently. At the beginning of this paper, I relate my experience of coming out as lesbian to the experience of coming out as a child witness of abuse in order to set the standard of how I conceptualize coming out. Coming out was an experience that connects LGBTQ people across the spectrum allowing me to use that experience to bring LGBTQ identities together. Assumptions about the coming out experience in relation to sexual orientation and gender identity are challenged and a new theory emerges. Related to coming out, the experience of getting out of an abusive relationship reflects parallel perceptions around fear, risk, and vulnerability. It is by building the bridge between researcher and participants that I was able to challenge bias and create a new idea about the coming out/getting out process for LGBTQ survivors.

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Shams, Sajjad. "Minimal lead time quotation under service level constraint." Diss., Wichita State University, 2007. http://hdl.handle.net/10057/1497.

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In today's competitive market, companies that offer a high quality service at a reasonable cost, survive the competition. A major factor contributing to high service quality is the ability to meet customers’ demand with a short lead time. Short lead time and on time delivery are two conflicting objectives. A reasonable balance between these objectives is necessary. The published research works on due date quotation make restrictive assumptions regarding the production process, considering only the production lead time, ignoring suppliers lead times, and/or rejecting some orders. No model can be found in the literature that considers all of these characteristics simultaneously. The proposed research considers a system to which orders arrive over time. Every order has a desired range of delivery date as defined by the customer. We consider order cost of delay that represents the cost of quoting due dates greater than requested. A two phase model is considered that assumes that production is constrained by a supply process. At arrival, each order is to be assigned a due date based on the status of the system. The system status is affected by internal factors including the level of WIP as well as external factors such as the supplier process. The due dates are to be assigned so that company’s objectives, defined by customer satisfaction and retention are achieved. It is desired to accept all orders, and to maximize on-time delivery of orders without placing any restriction on the behavior of the production process. The comparative results indicate that the proposed procedure is effective in quoting minimum lead times to achieve a given level of customer satisfaction.
Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering
"December 2007."
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Shams, Sajjad Cheraghi S. Hossein. "Minimal lead time quotation under service level constraint /." Diss., A link to full text of this thesis in SOAR, 2007. http://hdl.handle.net/10057/1497.

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Hemingway, Jennifer M. "Low Level Lead Exposure and Postural Balance in Children." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353099859.

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32

Fortune, Tyler John. "Chronic low-level lead exposure affects the monoaminergic system in the mouse supererior olivary complex." Diss., [Missoula, Mont.] : The University of Montana, 2007. http://etd.lib.umt.edu/theses/available/etd-12172007-145904/unrestricted/Fortune_Tyler_Thesis.pdf.

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33

Baillie, Alice Lydia. "The relationship between leaf cellular architecture and leaf-level photosynthesis." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19798/.

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34

Triantafyllidou, Simoni. "Lead (Pb) Contamination of Potable Water: Public Health Impacts, Galvanic Corrosion and Quantification Considerations." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/77215.

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The issue of lead exposure through drinking water was re-examined in light of modern public health goals, recent high-profile cases of elevated lead in water, and emerging concerns regarding the efficacy of legally mandated remedial strategies. A critical literature review revealed that serious lead-in-water hazards are present at many US schools and homes, and that the threat to individuals is not eliminated by existing regulations. Health studies have provided strong links between lead in water and lead in blood of exposed populations, even at relatively low levels of exposure compared to reported lead occurrence in US tap water samples. As efforts shift from addressing pervasive lead sources that once elevated the blood lead of large percentages of the population, to more isolated individual cases requiring exceptional attention, the importance of carefully considering lead in water as a potential source for elevated blood lead increases. Consistent with decades of prior research linking elevated water lead to elevated blood lead (EBL), lead-contaminated water in the high-profile case of Washington DC markedly increased the incidence of EBL for very young children. Specifically, incidence of EBL for children aged ≤ 1.3 years increased more than 4 times during 2001-2003 when lead in water was high, compared to 2000 when lead in water was low. The incidence of EBL for children aged ≤ 1.3 years was highly correlated (R² = 0.81) to 90th percentile lead-in-water levels from 2000-2007, and the risk of exposure to high water lead levels varied markedly in different neighborhoods of the city. Analysis conducted herein focused on identifying "worst-case" neighborhoods and populations. Specifically, this was the first study of the Washington DC case to focus on infants who are most vulnerable to harm from lead in water, and to perform smaller area analysis at the neighborhood (i.e., zip code) level in order to capture pockets of high risk among local communities. Prior biokinetic modeling efforts, examining the potential adverse impacts of lead-in-water exposure, were re-examined to explicitly consider new public health goals. This included impacts on the most sensitive population groups (e.g., young children and particularly formula-fed infants), the potential variability in blood lead levels (BLLs) amongst exposed individuals within those groups (e.g., most sensitive children at the upper tail of the BLL distribution), more conservative BLL thresholds reflecting low-level adverse effects (e.g., 5, 2 and 1 µg/dL versus 10 µg/dL), and the possibility of acute health impacts. This re-evaluation creates a paradigm shift, in that levels of lead in water that were previously considered inconsequential are demonstrated to be of concern in specific circumstances. The replacement of lead service lines in front of consumers' homes is a costly, federally mandated remedial action if a water utility exceeds the US EPA lead action level. Because utilities do not own the entire lead service line, they often only replace the portion of the service line up to the property line, typically with copper pipe. Experiences in Washington DC, as revealed by Freedom of Information Act requests, indicated that partial pipe replacements were not decreasing lead in water, and were actually associated with relatively high incidence of childhood lead poisoning. This prompted the first comprehensive investigation of potential long-term problems arising from galvanic corrosion between the remaining lead pipe and the newly installed copper pipe. Bench-scale experiments demonstrated that galvanic connections between lead pipe (new or aged) and copper pipe increased lead release into the water by 1.1-16 times, when compared to a full length of lead pipe alone. The small area of lead pipe adjacent to the copper joint (<0.5 ft) was gravely affected by galvanic corrosion, and accumulated a thick lead-rust layer (1 inch wide) that constituted a reservoir for semi-random particulate lead detachment into the water. The work on simulated partial pipe replacements revealed that under worst-case scenarios of highly contaminated water samples, most of the lead was not quantified if water samples were not mixed thoroughly after standard preservation (i.e., after addition of 0.15% v/v HNO₃), or if water samples were transferred from one bottle to another prior to preservation. While there is no reason to believe that sample handling and pre-treatment dramatically skew regulatory compliance with the US EPA lead action level, slight variations from one approved protocol to another may cause lead-in-water health risks to be dramatically underestimated. This is of special concern in unusual situations of "worst-case" individual exposures to highly contaminated water, associated with childhood lead poisoning. This work provides the water industry and health agencies with important new insights and perspectives on an old problem. Results can improve strategies to detect and mitigate lead-in-water hazards for individuals or populations, and inform future revisions to the US EPA Lead and Copper Rule.
Ph. D.
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Hedin, Ingrid. "Undersökning av möjliga faktorer till effektivisering av informations- och materialflöden." Thesis, Högskolan i Gävle, Industriell ekonomi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-27816.

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Till följd av ökande krav från kunder blir dagens konkurrenssituation på marknaden allt hårdare för företag. Dessa krav bidrar till att företagen måste satsa på ökad effektivitet och långsiktig lönsamhet. Lean är ett känt begrepp inom industrin som vid implementering syftar till att reducerar eller eliminera slöseri i informations- och materialflöden vilket leder till effektivisering. Denna studie bygger på ett problem som existerar i ett flertal informations- och materialflöden i en processindustri. Fallföretaget i denna studie är Iggesund Paperboard som önskar klarhet angående flödena samt minskade ledtider och lagernivåer. Syftet med studien är att undersöka hur internt materialflöde samt beställning och prognostisering av material kan effektiviseras för att reducera ledtid och lagernivåer. Studien utfördes genom en fallstudie där datainsamling på fallföretaget samlades in genom intervjuer, observationer och dokumentstudier. Parallellt samlades information också in genom litteratur. Datainsamlingen utgjorde sedan underlag till analys och slutsatser för denna studie. Resultatet i form av kartläggningen av informations- och materialflöden visar på ett komplext flöde med många aktiviteter som bidrar till slöseri. Orsakerna till slöseri i flödena är varierande och bidrar till ökade ledtider och lagernivåer. Vid kartläggningen utformades två bilder med två värdeflöden i varje bild som tillsammans med förbättringsförslag kan skapa kontroll och minska ledtider och lagernivåer. Det vetenskapliga bidrag som denna studie frambringar är att utöka kunskapen inom dokumentering och analysering, samt tillämpning av lösningar baserade på filosofin inom Lean, för administrativa arbetsuppgifter. Bidraget är således att kombinera och utföra samma tillämpning på ett informations- och materialflöde i helhet och inte var för sig. Förslag till vidare forskning är att utföra undersökningen som gjort i studien under en längre tidsperiod samt i fler miljöer för att ge prov på ökad trovärdighet.
Companies meet tougher competition at the marketplace as a consequence of increasing customer demand. As a result they have to focus on increasing their efficiency and look for long-term profitability. Lean is a known concept within the world of industries that aims to reduces or eliminates waste in information- and material flows which will lead to effectiveness. The findings of his study are based on a problem within a process industry. The problem comprises information- and material flows where the company Iggesund Paper requests clarity in the flows, and reduced lead time and stock levels. The purpose with this study is to investigate how internal material flow, forecasting orders and ordering materials can be developed to be more efficient and reduce lead-time and stock levels. This study is carried out as a case-study where the data was collected through interviews, observations, document studies and literature review. The data collection gave a solid ground for further analysis and conclusions. The value stream mapping and the description of the information- and material flows indicates and identifies complexity and activities contributing to waste. This situation leads to increasing lead-times and stock levels. The cause of the situation is varied but with the maps of the flows and the improvement proposals improvements can be made and effectiveness can be achieved. The theoretical contribution of this study is to extend research and considering applying tools within the Lean philosophy on administrative work, and together with the same application on work with material flow this study combine the proposals of improvements for the entire process. Suggestions for further research are to extend the time of the field study and likewise apply the methods of the study in additional situations to extend the validity and reliability.
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36

Oguma, Andrew Y. "Assessing the Effects of Low-Level Lead Contamination in Freshwater Sediments using Community-Level and Functional Indicators." Thesis, University of Louisiana at Lafayette, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3622951.

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Anthropogenic lead releases into the environment often end up in aquatic sediments. Ecotoxicologists have historically studied biological effects of toxicants, such as lead, using individuals or populations as models in laboratory settings. It has recently been suggested that because such bottom-up approaches can be difficult to extrapolate to actual effects of contaminants in the field, more research should take a top-down perspective. My project therefore aimed to investigate sediment lead effects at the community level, as well as on ecosystem function. Studies were conducted in a lake with a gradient of low-level sediment lead contamination. An assessment of benthic macroinvertebrate communities at fifty points in the lake revealed a negative correlation between sediment lead concentration and community abundance and diversity. Leaf-litter bags were deployed at thirty of the same points and decomposition rate was assessed after thirty days. Analyses indicated that decomposition rate decreased with increasing sediment lead concentration. Acute lead bioassays, using benthic macroinvertebrates collected from different areas of the lake, revealed that communities from the contaminated area were more tolerant to lead than were communities from uncontaminated areas. The pattern of increased community tolerance as a result of chronic exposure to low-level sediment lead was confirmed with macrobenthic communities that had been pre-exposed to environmentally-relevant lead concentrations for eighteen months in sediment mesocosms. Communities exposed to elevated lead levels had an increased tolerance when exposed to lethal lead levels. This was supported by the observed reduction in abundance and diversity that correlated with an increase in benthic macroinvertebrate community tolerance to lead. Additionally, reductions in leaf-litter decomposition, a vital ecosystem function in lentic systems, were also correlated with reductions in benthic macroinvertebrate abundances. Overall, the low-levels of sediment lead in the lake system appeared to have adverse effects on both structural and functional aspects of ecological integrity. Because sediment concentrations in the lake system were largely below widely accepted guidelines that are considered to be protective of benthic macroinvertebrates, my results have implications for risk-assessment in lentic systems contaminated with lead.

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37

Rowe, Brent R. "Will Outsourcing IT Security Lead to a Higher Social Level of Security?" NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-03272007-163006/.

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More firms outsource information technology (IT) security activities each year, as they determine that they can achieve cost savings or a higher level of security at the same cost. However, despite the estimated benefits, many firms still fail to see a clear positive net benefit from their (private) perspective, given the risks and costs involved. This paper investigates the positive externalities associated with IT security outsourcing. My research suggests that, when one organization decides to outsource its security, both direct and indirect benefits can accrue to other organizations and users. In this paper I analyze how a variety of decision characteristics affect whether and to what level such positive externalities will result. I also discuss implications for public policy and for firm-level decision making.
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38

Lu, Wuyi. "Customer service level in Multi-variant lean inventory." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490108.

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The research interest in multi-variant lean inventory is quite recent and effective general solution methods have yet to be developed. We propose new solution methods to manage multi-variant inventory for a number of scenarios. The mathematical analyses and three theoretical models are developed to calculate the average customer service level for these scenarios.
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39

Metcalfe, Michelle J. "Monitoring environmental features using leaf stomatal characteristics." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/4698/.

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It is recognised that atmospheric CO(_2) concentrations are increasing, with concerns raised as to the global impact continued rises may have. Plant stomatal parameters have been suggested as a means of monitoring changing CO(_2) levels. In order to assess their suitability for use, a thorough examination of leaf characteristics within a variety of surroundings was undertaken. Environments examined included both natural variations in CO(_2), which incorporated a variety of environmental influences and artificially enhanced ones where it was possible to monitor specific responses to variable CO(_2) levels. A short term study of Ranunculus ficaria, Sambucus nigra and Hedera helix revealed considerable variation in stomatal parameters, with inconsistent responses observed between and within species. These variations could not be attributed to CO(_2) changes and were assigned to a combination of other factors. R. ficaria grown in an artificial environment at ambient and elevated CO(_2) produced significant and consistent changes in stomatal parameters. Stomatal density and index were found to be reduced at elevated CO(_2) concentrations, with a decrease in guard cell dimensions. Salix herbacea, growing along a naturally reduced CO(_2) partial pressure gradient further highlighted the extent of variation in stomatal parameters in extant material within a species. No consistent stomatal trends associated with changing CO(_2) levels were observed. This inherent variation must be considered before any conclusions can be made regarding stomatal parameters obtained from fossil material. The novel application of molecular biology techniques to identify S. herbacea leaves was partially successful. However, identification of leaf macrofossils was not possible, due to the inferior preservation of DNA. However, the technique will provide a useful tool for identification if suitably preserved macrofossil fragments were available. S. herbacea leaf macrofossils revealed no consistent correlation to past changes in CO(_2) levels. The use of as an additional tool with which to monitor environmental change once again showed variation, and was not associated closely with changes in CO(_2) levels or stomatal parameters. In light of this work it would appear that the use of stomatal parameters is of limited value as a model to monitor environmental change, in the absence of information concerning other variables, and as such must be treated with caution.
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40

Harkins, S. W. "Blood Lead and Decision Speed in Working Age Adults." VCU Scholars Compass, 2005. http://scholarscompass.vcu.edu/etd/772.

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Lead is a central nervous system poison. Healthy People 2010 established a target blood lead level (BLL) for children of 0 μg/dL by 2010, but is silent with regard to any changes in BLLs standards for working age adults. In this paper, the relation of BLL to performance on two neurobehavioral tests was assessed in working age adults (N = 4909; Age 20 to 59 years; 51.4% Female) employing data from the Third National Health and Nutrition Survey (NHANES 111). Multiple linear regression analyses indicated a significant effect of BLL on time taken to complete an attention demanding cognitive task (Symbol Digit Substitution Task, SDST) but not accuracy of performance of the SDST or simple reaction time, after controlling for confounding variables of age, sex, race-ethnicity, and education. Persons with BLL ≥5 μg /dL took longer (multivariate adjusted mean = 23.6 Sec, SE = 0.30) compared to individuals with BLLs <5 μg /dL (mean = 22.5 Sec, SE = 0.14). The results suggest that lead burden in working age persons impairs central nervous processes involving executive mental functions (decision speed and attention). The findings, if confirmed by case control and or cohort studies would indicate a need to reconsider currently accepted lead levels in working age adults.
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41

Crawford, Jason. "Lean Production in the Public Service Sector : Migrationsverket and the Missing Links in the Value Chain." Thesis, Uppsala universitet, Företagsekonomiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-177301.

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42

Qin, Yi. "Electrodeposition and characterisation of lead-free solder alloys for electronics interconnection." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/7788.

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Conventional tin-lead solder alloys have been widely used in electronics interconnection owing to their properties such as low melting temperature, good ductility and excellent wettability on copper and other substrates. However, due to the worldwide legislation addressing the concern over the toxicity of lead, the usage of lead-containing solders has been phased out, thus stimulating substantial efforts on lead-free alternatives, amongst which eutectic Sn-Ag and Sn-Cu, and particularly Sn-Ag-Cu alloys, are promising candidates as recommended by international parties. To meet the increasing demands of advanced electronic products, high levels of integration of electronic devices are being developed and employed, which is leading to a reduction in package size, but with more and more input/output connections. Flip chip technology is therefore seen as a promising technique for chip interconnection compared with wire bonding, enabling higher density, better heat dissipation and a smaller footprint. This thesis is intended to investigate lead-free (eutectic Sn-Ag, Sn-Cu and Sn-Ag-Cu) wafer level solder bumping through electrodeposition for flip chip interconnection, as well as electroplating lead-free solderable finishes on electronic components. The existing knowledge gap in the electrochemical processes as well as the fundamental understanding of the resultant tin-based lead-free alloys electrodeposits are also addressed. For the electrodeposition of the Sn-Cu solder alloys, a methanesulphonate based electrolyte was established, from which near-eutectic Sn-Cu alloys were achieved over a relatively wide process window of current density. The effects of methanesulphonic acid, thiourea and OPPE (iso-octyl phenoxy polyethoxy ethanol) as additives were investigated respectively by cathodic potentiodynamic polarisation curves, which illustrated the resultant electrochemical changes to the electrolyte. Phase identification by X-ray diffraction showed the electrodeposits had a biphasic structure (β-Sn and Cu6Sn5). Microstructures of the Sn-Cu electrodeposits were comprehensively characterised, which revealed a compact and crystalline surface morphology under the effects of additives, with cross-sectional observations showing a uniform distribution of Cu6Sn5 particles predominantly along β-Sn grain boundaries. The electrodeposition of Sn-Ag solder alloys was explored in another pyrophosphate based system, which was further extended to the application for Sn-Ag-Cu solder alloys. Cathodic potentiodynamic polarisation demonstrated the deposition of noble metals, Ag or Ag-Cu, commenced before the deposition potential of tin was reached. The co-deposition of Sn-Ag or Sn-Ag-Cu alloy was achieved with the noble metals electrodepositing at their limiting current densities. The synergetic effects of polyethylene glycol (PEG) 600 and formaldehyde, dependent on reaching the cathodic potential required, helped to achieve a bright surface, which consisted of fine tin grains (~200 nm) and uniformly distributed Ag3Sn particles for Sn-Ag alloys and Ag3Sn and Cu6Sn5 for Sn-Ag-Cu alloys, as characterised by microstructural observations. Near-eutectic Sn-Ag and Sn-Ag-Cu alloys were realised as confirmed by compositional analysis and thermal measurements. Near-eutectic lead-free solder bumps of 25 μm in diameter and 50 μm in pitch, consisting of Sn-Ag, Sn-Cu or Sn-Ag-Cu solder alloys depending on the process and electrolyte employed, were demonstrated on wafers through the electrolytic systems developed. Lead-free solder bumps were further characterised by material analytical techniques to justify the feasibility of the processes developed for lead-free wafer level solder bumping.
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43

Langlois, Carolyn M. "Levels of Emotional Awareness: A psychophysiological investigation." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253561949.

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44

Puchala, Sarah E. "The Relationship Between Adiponectin Levels and Appendicular Lean Mass in Postmenopausal Women." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1436185475.

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45

Nousiainen, O. (Olli). "Characterization of second-level lead-free BGA interconnections in thermomechanically loaded LTCC/PWB assemblies." Doctoral thesis, Oulun yliopisto, 2010. http://urn.fi/urn:isbn:9789514263538.

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Abstract Low-temperature co-fired ceramic (LTCC) based system-in-package (SiP) is an emerging multilayer module technology for wireless communication applications, mainly due to its excellent high-frequency material properties. LTCC-SiP modules are typically soldered onto an organic motherboard, but the lifetime of the 2nd-level solder joints is often poor due to the high stress level of the joints in test/field conditions. Moreover, using lead-free solders in the interconnections of LTCC modules raised new questions about the feasibility and reliability of the solder joints in LTCC applications. Therefore, the characteristic features of the 2nd-level solder joint configuration were determined in this thesis work. It was proved that collapsible Sn4Ag0.5Cu spheres are not a feasible option in LTCC/PWB assemblies with a large global thermal mismatch; a non-collapsible ball grid array (BGA) joint with a plastic core solder balls (PCSBs) was required to attain an adequate lifetime for such assemblies. To enhance the thermal fatigue endurance of the non-collapsible lead-free joints, a novel BGA joint consisting of Sn7In4.1Ag0.5Cu solder and PCSBs was developed. Moreover, this work proved that there is a relationship between the primary failure mechanisms of various Sn-based lead-free solders and thermomechanically induced stress level in the present non-collapsible BGA joint configuration. The effect of the plating material of the solder lands on the failure mechanism of the BGA joints in the LTCC/PWB assemblies was studied. The results showed that the adverse phenomena related to the sintered Ag-based metallization materials can be avoided using electroless nickel with immersion gold (ENIG) as a deposit material. On the other hand, this study also demonstrated that the inadequate adhesion strength of the commercial base metallization in the ENIG-plated modules resulted in the disadvantageous failure mechanism of the test assemblies. Therefore, the criteria for material selection and the design aspects of reliable 2nd-level interconnections are discussed thoroughly in this thesis.
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46

Henriksson, Casper. "Lead the way : Hur främjar vi ”creative play” genom level design på mobila plattformar." Thesis, Högskolan på Gotland, Institutionen för speldesign, teknik och lärande, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-210614.

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47

Yocum, Susan Marie. "Effects of low level lead and cadmium on reproduction in Peromyscus leucopus and a study of lead concentration in small mammals from old orchards." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43073.

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Lead and cadmium frequently occur together as contaminants in polluted environments such as roadsides, urban areas, mines, and smelters. Few studies have been conducted to examine the possible interactive effects these metals may have on reproduction of wild species. The first part of this study was directed toward examining the effects of low level dietary lead and cadmium on reproduction in Peromyscus Jeucopus. Two laboratory studies were conducted. Treatment with combinations of 0, 1 or 4 μ/g lead acetate and/or cadmium chloride was found to have no effect on overall health or reproductive ability of white-footed mice. In a second, experiment mice were treated with combinations of 0 or 10 μg/g lead acetate and/or cadmium' chloride. Treatment was continued through three generations of mice (P1, Fl, F2); progeny of the P1 were paired with nonrelatives in the same group and continued on the same treatment. Percentage-of pairs producing at least one litter in a ten week period was reduced in mice receiving both lead and cadmium. By the F2 generation only one of ten pairs produced offspring. There were minor variations in litter parameters (# pups/litter, birth weight, weanling weight and viability of litters) measured for the three generations; however, treatment did not appear to greatly affect litters in those pairs which had litters. In the P1 generation kidney weights were lower in mice receiving lead and epididymidis weight was higher in mice receiving cadmium. Mice (P1) receiving cadmium and lead had lower numbers of spermatozoa/mg testis. Lead content of carcass, liver and kidneys was analyzed in mice from the P1 generation. The second part of this study examined the persistence of lead in the environment after the source of contamination has been removed. Short-tailed shrews (Blarina brevicauda) trapped in an orchard with a history of lead arsenate use had higher whole body lead concentrations than individuals of the same species trapped in a control orchard. Within the treated orchard lead concentrations in pine voles (Microtus pinetorum) were significantly higher than concentrations in short-tailed shrews.
Master of Science
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48

Hentschel, Rainer. "Water use – from leaf to tree to stand level." Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17497.

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Im Fokus dieser Arbeit steht die physiologische Reaktion von Einzelbäumen gegenüber Trockenheit. Das angewandte hydrodynamische Xylemwasserfluss (XWF) Model liefert eine hydrologische Abbildung der Einzelbäume. Aufgrund des funktionalen Zusammenhanges zwischen dem Blattwasserpotential und der stomatären Leitfähigkeit erlaubt das XWF Modell eine öko-physiologische Simulation der stomatären Reaktion auf Blattebene. Hieraus ergeben sich auch Rückschlüsse auf die Assimilationsleistung. Als integratives Maß des Verhältnisses zwischen der Kohlenstoffaufnahme und dem Wasserverbrauch werden die stabilen (Jahrring-) Isotope des Kohlen- und des Sauerstoffs analysiert. Des Weiteren werden Messungen des jährlichen Dickenwachstums sowie des Tagesganges der Xylem-Saftflussdichte untersucht. Die XWF Simulationen zeigen eine gute Übereinstimmung mit den Saftflussdichtemessungen an Buchen (Fagus sylvatica L.). Eine effektive stomatäre Regulation der Transpiration während der extreme Trockenheit des Jahres 2003 schütze die untersuchten Buchen vor einer Fehlfunktion des Wassertransportes. Gleichfalls konnte das Wachstum aufrechterhalten werden, was eine Remobilisierung von gespeichertem Kohlenstoff während Zeiten eingeschränkten Gasaustausches nahe legt. Des Weiteren zeigte sich Unterschiede in den (Wasser-) Nutzungsstrategien von Fichten (Picea abies L. Karst.), was auf eine physiologische Prädisposition der Gefährdung einzelner Bäume gegenüber Trockenstress hinweist. Die gemeinsame Betrachtung von hydrodynamischen Simulationen und öko-physiologischen Messungen kann dazu beitragen die komplexen physiologischen Prozesse auf Blattebene abzubilden und diese auf Baumebene zu projizieren. Weiterführend können somit die Vorhersagen des Wasserhaushaltes auf Bestandesebene angepasst und Auswirkungen des Klimawandels besser abgeschätzt werden.
This study focuses on the physiological response of individual trees towards drought. The hydrodynamic model of xylem water flow (XWF) applied provides a hydraulic map of the individual trees. Due to the functional linkage between the leaf water status and the stomatal conductance, the XWF model enables an eco-physiological representation of the stomatal response at the leaf level. As an integrative record of the ratio between water loss and carbon gain, the tree ring carbon and oxygen stable isotopes have been analyzed. Furthermore, measurements of seasonal growth and diurnal sap flow densities include in my study. The hydrodynamic XWF simulation shows good agreement with sap flow density measurements of beech trees (Fagus sylvatica L.). It demonstrates that the study trees were able to cope with the extreme drought events of the years 2003 due to a strong limitation of water loss by stomatal closure. The assessment of growth data and stable isotope measurements suggest an increased remobilization of stored carbohydrates during periods of limited gas exchange. Furthermore, differences in the resource use strategies of Norway spruce trees (Picea abies L. Karst.) suggest a physiological predisposition of individual trees toward drought stress. The combined investigation of hydrodynamic modeling and eco-physiological approaches helps to bridge the gap between the detailed examinations of physiological processes at the leaf level to the forecast of water use at the tree level. Thus, predictions of the water balance at the stand level may be adjusted for a better representation of the impact of climate change.
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49

Bäckström, Johan, and Faraz Kuhpai. "Improving group-level knowledge re-use." Thesis, KTH, Maskinkonstruktion (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146606.

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Due to knowledge being difficult to imitate, effective knowledge management provides several key competitive advantages. It involves managing knowledge within organizations in order to ensure the right knowledge reaching the right person at the right time.Scania CV AB is one of the world’s leading manufacturers of trucks, busses and engines for marine and industry purposes. As part of the work with streamlining processes, knowledge management has become a focus area within their R&D. This master thesis has been carried out at four groups grouped under the section UTP Process support, consisting of a mechanical workshop, logistics, improvement coaches, and logistics and measurement. The purpose was to identify areas with potential for improvement, and present suggestions for improvements, with reusability of knowledge as the main focus.A total of 132 interviews and surveys, and four workshops were conducted in order to gather data, generate improvement proposals and anchor ideas. A literature study was conducted to provide a frame of reference.A four-quadrant model was generated, to make possible the mapping of knowledge work within the involved groups. This aims to provide a general model supporting improvements in knowledge management, by establishing a conceptual frame of reference where ambition and current state can be compared, providing a base for improvements and follow-ups over time.The improvement coach group is at the forefront of the issues addressed in this thesis report, which in this context also poses their primary challenge. Suggestions on how work can keep improving are presented, including further developments of the group's so called skills matrix.For the other groups, freeing up time of experienced employees is recommended in order to transfer knowledge to less experienced colleagues. Furthermore, improving the availability of documents controlling the employees’ work is recommended, as well as ensuring these are fully updated to a larger extent. Lastly, the groups should work on increasing knowledge exchange between them and external parties, such as customers and suppliers.Future recommendations include carrying out a pilot study of the proposed model, in order to improve the model and examine how different business units within product development organizations can benefit from it. A follow-up should be carried out to examine if the recommendations have made a difference.
En effektiv kunskapshantering kan ge unika konkurrensfördelar, då kunskap är svår att imitera. Knowledge management inbegriper hantering och ledning av kunskap i organisationer för att säkerställa att rätt kunskap når rätt person vid rätt tillfälle.Scania CV AB är en av världens ledande tillverkare av lastbilar, bussar och motorer för marin och industri. I arbetet att effektivisera processer har kunskapshantering blivit ett fokusområde för R&D. Detta examensarbete har utförts mot fyra grupper under sektionen UTP Process support, med en mekanisk verkstad, logistik, förbättringscoacher samt logistik och mätrum. Syftet var att identifiera områden med förbättringspotential och presentera förslag för fortsatt förbättringsarbete, med återanvändbarhet av kunskap som fokus.Totalt 132 intervjuer och enkäter, och fyra workshopar genomfördes för att samla in data, generera förbättringsförslag och förankra idéer. En litteraturstudie genomfördes för att ge en referensram för studien.För att kartlägga hur kunskapsarbetet fungerade på de olika grupperna, genererades en fyrfältsmodell. Denna syftar till att ge en generell metod för förbättringsarbete kring kunskapshantering, genom att formulera en konceptuell referensram där ambitionsnivå och nuläge kan jämföras, för att ge underlag till förbättringsarbete och uppföljning över tid.Gruppen med förbättringscoacher ligger i framkant i frågorna som examensarbetet behandlar, vilket i detta sammanhang också utgör dess främsta utmaning. Förslag ges på hur arbetet kan fortsätta förbättras, däribland en vidareutveckling av gruppens så kallade kompetensmatris.För de övriga grupperna rekommenderas att frigöra tid för erfarna medarbetare att överföra kunskap till mindre erfarna. Vidare rekommenderas att tillgängligheten av dokument som styr arbetet ses över, och att dessa hålls fullständigt uppdaterade i högre utsträckning. Slutligen bör grupperna arbeta för ökat kunskapsutbyte mellan grupperna och externa parter såsom kund och leverantör.Som framtida arbete rekommenderas en pilotstudie av den framtagna modellen, för att förbättra denna och undersöka hur olika grupper inom produktutvecklingsorganisationer kan dra nytta av den. En uppföljning bör genomföras för att undersöka om implementering av givna rekommendationer har gjort skillnad.
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50

Fortune, Tyler John. "CHRONIC LOW-LEVEL LEAD EXPOSURE AFFECTS THE MONOAMINERGIC SYSTEM IN THE MOUSE SUPERIOR OLIVARY COMPLEX." The University of Montana, 2008. http://etd.lib.umt.edu/theses/available/etd-12172007-145904/.

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Abstract:
Low-level lead (Pb) exposure is associated with behavioral and cognitive dysfunction. It is not clear how Pb produces these behavioral changes but low-level Pb exposure and learning disabilities have been associated with altered auditory temporal processing in both humans and animals. Temporal processing is used to decode complex sounds and to detect a signal within a noise background, and it is thought that neurons of the superior olivary complex (SOC) in the brainstem play a role in sound detection in noisy environments and in selective auditory attention. The SOC receives a catecholaminergic and a serotonergic innervation from the locus coeruleus and the dorsal raphe respectively. While the physiological role of the noradrenergic input has yet to be defined, serotonin is involved in auditory temporal processing. Because Pb exposure modulates auditory temporal processing, the serotonergic system is a potential target for Pb. The current study was undertaken to determine whether developmental Pb exposure preferentially changes the expression of serotonin within the SOC. Pb-treated mice were exposed to no Pb, 0.01 mM (very low) or 0.1 mM (Low) Pb acetate throughout gestation and through 21 days postnatally. Brainstem sections from control and Pb-exposed mice were immunostained for the vesicular monoamine transporter 2 (VMAT2), serotonin, and dopamine beta hydroxylase (DβH, a marker for norepinephrine) in order to elucidate the effect of Pb on monoaminergic input into the SOC. In addition, sections were immunolabeled with antibodies to VGLUT1, VGAT and VAChT in order to determine whether Pb exposure alters the glutaminergic, gaba-ergic, or cholinergic systems. Pb exposure caused a significant decrease in VMAT2, 5HT, and DβH expression while VGLUT1, VGAT and VAChT showed no change. These results provide evidence that Pb exposure during development alters normal monoaminergic expression in the auditory brainstem.
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