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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
481

Spatial variability in modern brachiopod assemblages: paleoecological and geochemical implications

Rodland, David Laurence 17 June 2003 (has links)
An accurate understanding of global patterns through geologic time depends upon multi-scale analyses of spatial variation within narrow temporal intervals. This work investigates geochemical and paleoecological patterns in modern brachiopod faunas which may serve as analogues for ancient brachiopod assemblages. The paleoclimatic utility of delta18O in the phosphatic phase of lingulid brachiopod shells requires valve secretion in equilibrium with seawater, an assumption tested (and rejected) when analyzed at scales ranging from millimeters to kilometers. By contrast, biological encrustation of the brachiopod fauna of the Southeast Brazilian Bight shows strong sensitivity to microenvironmental conditions such as host identity, shape, and size, and may prove useful for studies of ancient planktonic productivity. Comparison of encrustation patterns on naturally occurring brachiopods and bivalves collected from the same sites, and occupying the same size range, demonstrates that the results of encrustation studies on modern bivalves cannot be directly applied to ancient brachiopods. However, careful comparisons may reveal patterns of epibiont selectivity and the impact of changes in the relative abundance of host shells through geologic time. Finally, neither epibiont abundance nor diversity increase with host age as indicated by dated brachiopod shells from the past 1000 years. These results suggest that the temporal resolution of epibiont assemblages matches their spatial resolution, and strengthen evidence for competition among encrusting taxa. By documenting geochemical and paleoecological variation within shells and across a continental shelf, this work demonstrates the importance of understanding spatial variation across all scales before interpreting trends through time. / Ph. D.
482

Nitrogen release, tree uptake, and ecosystem retention in a mid-rotation loblolly pine plantation following fertilization with 15N-enriched enhanced efficiency fertilizers

Werner, Amy 11 June 2013 (has links)
Nitrogen is the most frequently limiting nutrient in southern pine plantations.  Previous studies found that only 10 to 25% of applied urea fertilizer N is taken up by trees.  Enhanced efficiency fertilizers could increase tree uptake efficiency by controlling the release of N and/or stabilize N.  Three enhanced efficiency fertilizers were selected as a representation of fertilizers that could be used in forestry: 1) NBPT treated urea (NBPT urea), 2) polymer coated urea (PC urea), and 3) monoammonium phosphate coated NBPT treated urea (MC NBPT urea). Urea, MC NBPT urea, and NBPT urea fertilizer treatments showed an extractable NH4+ spike 14 days after fertilization while the polymer coated urea showed a spike in NH4+ 49 days after fertilization. Total ecosystem recovery of fertilizer in each treatment was; MC NBPT urea, 51.29 g N; NBPT urea, 48.87 g N; urea, 45.09 g N; and PC urea, 31.30 g N which represents 78.7%, 74.7%, 72.1%, and 47.6% respectively of the total N applied.  For the MC NBPT urea, NBPT urea, and PC urea treatments the largest sinks for N were the forest floor and mineral soil.  The largest sink for fertilizer applied N in the urea treatment was in the tree.  The 2011 foliage cohort was the largest sinks for fertilizer N recovered by the tree.  N volatilization was around 20% for all fertilizer treatments except polymer coated fertilizer, which was 1.1%.  Urea preformed the same as the soluble enhanced efficiency fertilizers and better than the PC urea fertilizer.  The results emphasize the importance of climatic conditions on fertilizer release and effectiveness. / Master of Science
483

Continuity or Colonization in Anglo-Saxon England? Isotope Evidence for Mobility, Subsistence, Practice and Status at West Heslerton.

Montgomery, Janet, Evans, J.A., Powesland, D., Roberts, Charlotte A. January 2005 (has links)
No / The adventus Saxonum is a crucial event in English protohistory. Scholars from a range of disciplines dispute the scale and demographic profile of the purported colonizing population. The 5th-7th century burial ground at West Heslerton, North Yorkshire, is one of the few Anglian cemeteries where an associated settlement site has been identified and subjected to extensive multidisciplinary postexcavation study. Skeletal and grave good evidence has been used to indicate the presence of Scandinavian settlers. A small, preliminary study using lead and strontium isotope analysis of tooth enamel, mineralized in early childhood, from Neolithic/Early Bronze Age (n = 8), Iron Age (n = 2), and Early Anglo-Saxon (n = 32) skeletons, was carried out to directly investigate this hypothesis. Results suggest that lead provides dissimilar types of information in different time periods. In post-Roman England, it appears to reflect the level of exposure to circulated anthropogenic rather than natural geological lead, thus being a cultural rather than geographical marker. Consequently, only strontium provides mobility evidence among the Anglian population, whereas both isotope systems do so in pre-Roman periods. Strontium data imply the presence of two groups: one of local and one of nonlocal origin, but more work is required to define the limits of local variation and identify immigrants with confidence. Correlations with traditional archaeological evidence are inconclusive. While the majority of juveniles and prehistoric individuals fall within the local group, both groups contain juveniles, and adults of both sexes. There is thus no clear support for the exclusively male, military-elite invasion model at this site.
484

Bitumen in Neolithic Iran: Biomolecular and isotopic evidence.

Gregg, M.W., Brettell, Rhea C., Stern, Ben January 2007 (has links)
No / This paper presents the results of the chemical analysis of materials recovered from two of the earliest agricultural villages in southwestern Iran and a late Neolithic pastoral encampment in nearby Khuzistan. Gas chromatography - mass spectrometry (GC-MS) revealed biomarker compounds characteristic of bitumen in residues from ceramic vessels supporting the excavators¿ contention that the interior surfaces of some vessels were coated with a thin layer of such material and confirmed that ¿fragments¿ collected during excavation were indeed bitumen. Biomolecular and isotopic analysis of the bitumen indicated that the sources utilized lie in the Susa and Deh Luran regions of southwestern Iran. / NERC (MSc); AHRC (PhD)
485

Using stable isotope analysis to identify Irish migrants in the Catholic Mission of St Mary and St Michael, Whitechapel

Beaumont, Julia, Montgomery, Janet, Wilson, Andrew S. January 2013 (has links)
No
486

An investigation of the origins of cattle and aurochs deposited in the Early Bronze Age barrows at Gayhurst and Irthlingborough

Towers, Jacqueline R., Montgomery, Janet, Evans, J., Jay, Mandy, Parker Pearson, M. 2009 October 1916 (has links)
Yes / The Early Bronze Age round barrows at Irthlingborough, Northamptonshire and Gayhurst, Buckinghamshire contained remarkably large quantities of cattle (Bos taurus) remains. At Irthlingborough, at least 185 skulls with smaller numbers of mandibles, shoulder blades and pelves were found together with a small number of skeletal elements from aurochs (Bos primigenius). In contrast, the remains from Gayhurst are dominated by the limb bones from more than 300 animals. This study employed strontium isotope ratio analysis of cattle tooth enamel from 15 cattle and one aurochs to investigate the diversity of the animals’ origins at both sites and provide insights into Early Bronze Age funerary practices. Although strontium results show that most of the cattle and the aurochs included in this study were consistent with local origins, one animal from each barrow was born remotely, most likely in western Britain. In addition, a second Gayhurst animal was consistent with origins in a region of chalk rather than the local Jurassic sediments.
487

The role of infant life histories in the construction of identities in death: An incremental isotope study of dietary and physiological status among children afforded differential burial

Craig-Atkins, E., Towers, Jacqueline R., Beaumont, Julia 21 August 2018 (has links)
Yes / Objectives Isotope ratio analyses of dentine collagen were used to characterize short-term changes in physiological status (both dietary status and biological stress) across the life course of children afforded special funerary treatment. Materials and Methods Temporal sequences of δ15N and δ13C isotope profiles for incrementally-forming dentine collagen were obtained from deciduous teeth of 86 children from four early-medieval English cemeteries. Thirty-one were interred in child-specific burial clusters, and the remainder alongside adults in other areas of the cemetery. Isotope profiles were categorized into four distinct patterns of dietary and health status between the final prenatal months and death. Results Isotope profiles from individuals from the burial clusters were significantly less likely to reflect weaning curves, suggesting distinctive breastfeeding and weaning experiences. This relationship was not simply a factor of differential age at death between cohorts. There was no association of burial location with stage of weaning at death, nor with isotopic evidence of physiological stress at the end of life. Discussion This study is the first to identify a relationship between the extent of breastfeeding and the provision of child-specific funerary rites. Limited breastfeeding may indicate the mother had died during or soon after birth, or that either mother or child was unable to feed due to illness. Children who were not breastfed will have experienced a significantly higher risk of malnutrition, undernutrition and infection. These sickly and perhaps motherless children received care to nourish them during early life, and were similarly provided with special treatment in death. / University of Sheffield Early Career Researcher Scheme by a grant awarded to ECA in 2014-15.
488

Auditory ossicles: a potential biomarker for maternal and infant health in utero

Leskovar, T., Beaumont, Julia, Lisic, N., McGalliard, S. 23 August 2019 (has links)
Yes / Background: Carbon (δ13C) and nitrogen (δ15N) isotope ratios of collagen from teeth and bone are used to study human nutrition and health. As bones are constantly remodelling throughout life, isotopic values of bone collagen represent an average of several years. In contrast, human teeth do not remodel and their primary dentine contains only the isotopic data from the time of formation. In contrast to all other bones, human auditory ossicles also appear not to remodel. As they develop in utero and finish formation in the first 2 years of life, their collagen should also represent isotopic values of these two relatively short periods. Aim: By comparing δ13C and δ15N data from ossicles and incremental dentine, this study aims to investigate how two developmental periods of the ossicles, in utero and the first 2 years of life, reflect in collagen obtained from the ossicles. Subject and methods: Ossicle and tooth samples of 12 individuals aged 0.5 ± 0.4 years to 13 ± 1 years from the nineteenth century St. Peter’s burial ground in Blackburn were collected and processed to obtain bulk bone and incremental dentine collagen which was measured for δ13C and δ15N. Results: Averaged δ13C and δ15N of ossicles are lower when compared to every age group except after 3 years of age. Average offset between ossicles and dentine of different groups ranges from 0.4–0.9‰ for δ13C and from 0.3–0.9‰ for δ15N, with highest counterbalance at birth and after the first 5 months after birth. Conclusions: There appears to be a systematic offset between the dentine and ossicle data. It seems that the second phase of development does not influence the isotopic values of collagen significantly and the data we are obtaining from ossicles represents the in utero period. / Research grant from The Society for the Study of Human Biology.
489

A new method for investigating the relationship between diet and mortality: hazard analysis using dietary isotopes

Redfern, R.C., DeWitte, S.N., Beaumont, Julia, Millard, A.R., Hamlin, C. 30 August 2019 (has links)
Yes / Bioarchaeological and clinical data show that diet influences health, and this relationship is crucial to how we understand past health with respect to sex and age. We propose a new method that coinvestigates the relationship between mortality risk and diet in the past. Our method integrates dietary stable isotope data (δ13 Carbon and δ 15 Nitrogen) from Roman Britain (N=659) with hazards analysis. The results show that these data can be informatively used in this type of analysis in general, and that in the context of Roman Britain, higher δ 13C is associated with lower risks of mortality while higher δ 15N is associated with elevated risks of mortality. Importantly, the results emphasize that a bioarchaeological approach to interpretation must be taken in order to more fully understand the results obtained by the method
490

Kinship practices in Early Iron Age southeast Europe: genetic and isotopic analysis of burials from the Dolge njive barrow cemetery, Dolenjska, Slovenia

Armit, I., Fischer, C-E., Koon, Hannah E.C., Nicholls, Rebecca A., Olalde, I., Rohland, N., Buckberry, Jo, Montgomery, J., Mason, P., Cresnar, M., Buster, L., Reich, D. 02 August 2022 (has links)
Yes / DNA analysis demonstrates that all seven individuals buried in an Early Iron Age barrow at Dolge njive, southeast Slovenia, are close biological relatives. Although group composition does not suggest strict adherence to a patrilineal or matrilineal kinship system, the funerary tradition appears highly gendered, with family links through both the male and female line being important in structuring communities. We explore the implications for our understandings of kinship and funerary practices in Early Iron Age southeast Europe. / This research forms part of ENTRANS: a collaborative project involving the Universities of Bradford, Zagreb and Ljubljana, and the Institute for the Protection of Cultural Heritage of Slovenia. ENTRANS (PI: Armit) received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 291827. The project is financially supported by the HERA Joint Research Programme (www.heranet.info) which is co-funded by AHRC, AKA, BMBF via PT-DLR, DASTI, ETAG, FCT, FNR, FNRS, FWF, FWO, HAZU, IRC, LMT, MHEST, NWO, NCN, RANNÍS, RCN, VR and The European Community FP7 2007-2013, under the Socioeconomic Sciences and Humanities programme. Research for this paper also received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 834087 (COMMIOS). The ancient DNA work was supported by NIH grant GM100233, John Templeton Foundation grant 61220, the Howard Hughes Medical Institute, and the Allen Discovery Center program, a Paul G. Allen Frontiers Group advised program of the Paul G. Allen Family Foundation.

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