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Studies of carbon's evolutionary path have been conducted via millimeter and submillimeter observations of circumstellar envelopes (CSEs), planetary nebulae (PNe), molecular clouds and comets. The 12C/13C isotope ratio was measured in Galactic molecular clouds using the CN isotopologs. A gradient of 12CN/13CN was determined to be 12C/13C = 6.01 DGC +12.28, where DGC is distance from the Galactic center. The results of CN are in agreement with those of CO and H2CO indicating a true ratio not influenced by fractionation effects or isotope-selective photodissociation. The 12C/13C isotope ratios in the envelopes of various types of stars were also measured from both CO and CN isotopologs. Such objects as carbon and oxygen-rich asymptotic giant branch (AGB) stars, supergiants, planetary nebulae, and S-type stars were observed. Results from this study indicate 12C/13C values for supergiants ~ 10 and AGB stars 12C/13C ~ 20- 76. Theory would suggest a lower ratio for objects undergoing third dredge-up, though this is seemingly not the case. Multiple carbon-bearing species including CO, HCN, HNC, CN, CS, and HCO+ have also been observed towards the oxygen-rich supergiant, VY CMa. This object has recently revealed a unique chemistry where carbon is not solely contained in CO, and may play a more important role in the chemical network of oxygen-rich circumstellar envelopes. Additionally, observations of species with carbon- carbon bonds, such as CCH and c-C3H2, have been conducted towards evolved planetary nebulae, such as the Helix and Ring nebulae. There is a close agreement in the inventories of species found in PNe and diffuse clouds, suggesting a potential molecular precursor to the interstellar medium. Observations of carbon-bearing species (H2CO and CO) in comets C/1995 O1 (Hale-Bopp), C/2001 Q4 (NEAT), and C/2002 T7 (LINEAR) have been conducted. Formaldehyde is known to have an extended distribution in these objects, likely arising from silicate-organic grains. Evidence of cometary fragmentation was also obtained for H2CO in comet T7 LINEAR as well as for HNC and HCO+ in Hale-Bopp. Such events could contribute to planetary distribution of organics.

Cotton is the most abundant natural fiber in the world. Many countries are involved in the growing, importation, exportation and production of this commodity. Paper documentation claiming geographic origin is the current method employed at U.S. ports for identifying cotton sources and enforcing tariffs. Because customs documentation can be easily falsified, it is necessary to develop a robust method for authenticating or refuting the source of the cotton commodities. This work presents, for the first time, a comprehensive approach to the chemical characterization of unprocessed cotton in order to provide an independent tool to establish geographic origin. Elemental and stable isotope ratio analysis of unprocessed cotton provides a means to increase the ability to distinguish cotton in addition to any physical and morphological examinations that could be, and are currently performed. Elemental analysis has been conducted using LA-ICP-MS, LA-ICP-OES and LIBS in order to offer a direct comparison of the analytical performance of each technique and determine the utility of each technique for this purpose. Multivariate predictive modeling approaches are used to determine the potential of elemental and stable isotopic information to aide in the geographic provenancing of unprocessed cotton of both domestic and foreign origin. These approaches assess the stability of the profiles to temporal and spatial variation to determine the feasibility of this application. This dissertation also evaluates plasma conditions and ablation processes so as to improve the quality of analytical measurements made using atomic emission spectroscopy techniques. These interactions, in LIBS particularly, are assessed to determine any potential simplification of the instrumental design and method development phases. This is accomplished through the analysis of several matrices representing different physical substrates to determine the potential of adopting universal LIBS parameters for 532 nm and 1064 nm LIBS for some important operating parameters. A novel approach to evaluate both ablation processes and plasma conditions using a single measurement was developed and utilized to determine the “useful ablation efficiency” for different materials. The work presented here demonstrates the potential for an a priori prediction of some probable laser parameters important in analytical LIBS measurement.

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.

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.

Yes / The study presents results of the investigations of diet based on carbon and nitrogen stable isotope ratios (δ13C and δ15N) of the bone collagen of individuals buried in medieval elite chamber graves from the territory of the state of the first Piasts, Poland (the second half of the 10th and the first half of the 11th century). The aim of the research was to determine the diet of individuals buried in such funerary structures, to compare this with commoners buried in ordinary graves, and investigate any sex-related patterns. Rib bone samples were taken from individuals buried in chamber graves at Bodzia, Dziekanowice, Pień and Sowinki. Results indicate that the elite male diet was based on C3 plants with possible contribution of some C4 plants (millet) and substantial consumption of animal proteins including fish. The bone collagen δ13C and δ15N of male chamber burials suggested consumption of higher trophic level foodstuffs (meat and fish) whilst the female diet, and that of the juveniles, was similar to the commoners in the rest of the population.

Inductively coupled plasma mass spectrometry is a well-established technique for the measurement of isotope ratios. Double focussing mass analysers enable increased resolution to be applied to separate spectroscopic interferences, or the use of multi-collector detection techniques for high precision isotope ratio determinations. For the Central Science Laboratory (CSL), trace elements team, methods were developed for Zn and Fe isotope ratio measurements in acid digested faecal samples from a human nutritional study. For Zn, a novel high resolutionlmulticollector combination was employed; for Fe a single collector, high resolution method was used. In both cases, samples from the nutritional study known to contain the analytes in natural isotopic abundance were used to correct for the mass bias. Two independent methods for determining Zn and Fe isotope ratios were used to validate the measurement strategies. The team at CSL are also involved in the authentication of food products. Isotope ratio and elemental concentration data were used to determine the geographical origin of rice samples, and to distinguish between traditional and modem Basmati rice grown in India and Pakistan. NERC Isotope Geosciences Laboratory are primarily concerned with the achievable accuracy and precision of an isotope ratio measurement. Use of a mass bias correction expression appropriate to the ICP-MS instrument is essential for high quality isotope ratio measurements. Cd and Sn were used to study the variation of the mass bias in a double focussing ICP-MS system with time, absolute mass and mass difference. It was proposed that mass bias should be considered as a result of the change in the instrument response with mass, and not a fundamental parameter in its own right. A method for determination of the best mass bias correction model for an individual instrument, through examination of the instrument response function was developed.

Seagrass habitats are highly productive ecosystems that support marine food webs and provide essential habitat for a variety of species. Seagrass coverages are declining in abundance worldwide. For southeastern Florida in particular, one of the main causes of the decline is disturbance from dredging and removal of substrate. Seagrass beds at three locations in the vicinity of Port Everglades, Florida were assessed for their trophic contribution to the marine organisms in the area. Seagrasses, algae, invertebrates, and vertebrates from the beds were identified and analyzed for stable carbon and nitrogen isotope ratios to determine their contribution as a food source. Significant differences were found in both δ13C and δ15N between both seagrass species and among the three sites. The δ13C of Johnson’s seagrass Halophila johnsonii ranged from -16.28 to -11.27‰ while shoal grass Halodule wrightii ranged from -15.78 to -13.36‰. The δ15N for H. wrightii were more constrained than those of H. johnsonii, 4.69 to 7.08‰ versus 0.80 to 7.86‰, respectively. Neither seagrass species appeared to be a dominant food source for marine organisms at all three study sites. However, the δ13C and δ15N of both seagrass species, Halophila johnsonii and Halodule wrightii, did fall in the fractionation range of potential consumers, -28.78 to -17.11‰ and 1.96 to 12.63‰, indicating that these animals could be ingesting pieces of seagrass while grazing on epiphytes and other primary producers in the area. Epiphytes found on the seagrass blades appeared to be a greater trophic contributor to local organisms. So while the seagrass species in question may not have been major contributors to the diet of many of the local consumers, the seagrasses nontheless played a vital role as habitat for the epiphytes that did serve as a trophic resource in these communities.

The isotopic composition of the organic components of an animal's body, with respect to carbon and nitrogen, reflect the weighted average of the isotopic compositions of the animal's food sources, with a certain degree of enrichment in the heavier isotopes. Thus, by comparing the isotopic compositions of the animal and all the potential food sources, it is possible to ascertain the relative proportions of each availible food source in its diet, if the various food sources are sufficiently isotopically distinct. This approach is particularly usefull in estuarine communities where food-webs tend to be complex and where there are several sources of primary productivity. In this study it was used on two types of claw in an arctic and a temperate estuarine tidal flat in order to assess the importance of terrestrially fixed organic matter to each community. The results indicated that while marine and terrestrial organics were important food sources in the arctic tidal flat, the clams in the temperate site depended mostly on marine organics. / Thesis / Bachelor of Science (BSc)

Yes / Objectives Studies of the carbon and nitrogen stable isotope ratios (δ13C and δ15N) of modern tissues with a fast turnover, such as hair and fingernails, have established the relationship between these values in mothers and their infants during breastfeeding and weaning. Using collagen from high-resolution dentine sections of teeth which form in the perinatal period we investigate the relationship between diet and physiology in this pivotal stage of life. Materials and Methods Childhood dentine collagen δ13C and δ15N profiles were produced from horizontal sections of permanent and deciduous teeth following the direction of development. These were from two 19th-century sites (n = 24) and a small number (n = 5) of prehistoric samples from Great Britain and Ireland. Results These high-resolution data exhibit marked differences between those who survived childhood and those who did not, the former varying little and the latter fluctuating widely. Discussion Breastfeeding and weaning behavior have a significant impact on the morbidity and mortality of infants and the adults they become. In the absence of documentary evidence, archaeological studies of bone collagen of adults and juveniles have been used to infer the prevalence and duration of breastfeeding. These interpretations rely on certain assumptions about the relationship between isotope ratios in the bone collagen of the adult females and the infants who have died. The data from this study suggest a more complex situation than previously proposed and the potential for a new approach to the study of maternal and infant health in past populations.