Studies on Pneumococcal Cross Infection and the Relationship of Pneumococci to Acute Respiratory Disease in Early Life

Abstract Not Provided

The Inherent Tracer Fingerprint of Captured CO2.

Carbon capture and storage (CCS) is the only currently available technology that can directly reduce anthropogenic CO2 emissions arising from fossil fuel combustion. Monitoring and verification of CO2 stored in geological reservoirs will be a regulatory requirement and so the development of reliable monitoring techniques is essential. The isotopic and trace gas composition - the inherent fingerprint - of captured CO2 streams is a potentially powerful, low cost geochemical technique for tracking the fate of injected gas in CCS projects; carbon and oxygen isotopes, in particular, have been used as geochemical tracers in a number of pilot CO2 storage sites, and noble gases are known to be powerful tracers of natural CO2 migration. However, the inherent tracer fingerprint in captured CO2 streams has yet to be robustly investigated and documented and key questions remain, including how consistent is the fingerprint, what controls it, and will it be retained en route to and within the storage reservoir? Here we present the first systematic measurements of the carbon and oxygen isotopes and the trace noble gas composition of anthropogenic CO2 captured from combustion power stations and fertiliser plants. The analysed CO2 is derived from coal, biomass and natural gas feedstocks, using amine capture, oxyfuel and gasification processes, from six different CO2 capture plants spanning four different countries. We find that δ13C values are primarily controlled by the δ13C of the feedstock while δ18O values are predominantly similar to atmospheric O2. Noble gases are of low concentration and exhibit relative element abundances different to expected reservoir baselines and air, with isotopic compositions that are similar to air or fractionated air. The use of inherent tracers for monitoring and verification was provisionally assessed by analysing CO2 samples produced from two field storage sites after CO2 injection. These experiments at Otway, Australia, and Aquistore, Canada, highlight the need for reliable baseline data. Noble gas data indicates noble gas stripping of the formation water and entrainment of Kr and Xe from an earlier injection experiment at Otway, and inheritance of a distinctive crustal radiogenic noble gas fingerprint at Aquistore. This fingerprint can be used to identify unplanned migration of the CO2 to the shallow subsurface or surface

Health, education, and social care provision after diagnosis of childhood visual disability

Aim: To investigate the health, education, and social care provision for children newly diagnosed with visual disability.Method: This was a national prospective study, the British Childhood Visual Impairment and Blindness Study 2 (BCVIS2), ascertaining new diagnoses of visual impairment or severe visual impairment and blindness (SVIBL), or equivalent vi-sion. Data collection was performed by managing clinicians up to 1-year follow-up, and included health and developmental needs, and health, education, and social care provision.Results: BCVIS2 identified 784 children newly diagnosed with visual impairment/SVIBL (313 with visual impairment, 471 with SVIBL). Most children had associated systemic disorders (559 [71%], 167 [54%] with visual impairment, and 392 [84%] with SVIBL). Care from multidisciplinary teams was provided for 549 children (70%). Two-thirds (515) had not received an Education, Health, and Care Plan (EHCP). Fewer children with visual impairment had seen a specialist teacher (SVIBL 35%, visual impairment 28%, χ2p < 0.001), or had an EHCP (11% vs 7%, χ2p < 0 . 01).Interpretation: Families need additional support from managing clinicians to access recommended complex interventions such as the use of multidisciplinary teams and educational support. This need is pressing, as the population of children with visual impairment/SVIBL is expected to grow in size and complexity.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

Characterizing shallow aquifers using tritium and ¹⁴C: Periodic sampling based on tritium half-life.

Thirteen water-production wells in glacial sediments in and around Waterloo, Ontario, (Canada) were sampled for major ions, 3H, 13C, 14C and 18O in 1976 and again in 1988 to gauge the movement of bomb-spike tritium and 14C through the Waterloo aquifer and also to assess the reliability of a hydrogeochemical interpretation of the dynamic character of an aquifer based only on single sampling episode. The suite of samples collected in 1976 was not able to indicate how fast the tritium spike was moving or even if each well-screen was intercepting the front end or tail end of the bomb-spike peak corresponding to infiltration of mid-1960s precipitation. The second sampling event portrayed movement which, qualitatively at least, gave information relating to the more permeable zones of the aquifer and direction of water movement. Water from all but one of the 13 wells sampled in 1988 registered a drop in tritium relative to the 1976 sampling. A well is deemed to be intercepting the front end of the peak of the bomb-spike if its 1988 tritium activity (&plusmn;2 TU analytical uncertainty) is greater than one half that of the tritium activity of well water measured in 1976 (&plusmn;8 TU uncertainty). Only one well and two shallow piezometers met this criterion. Ten wells had TU1988/TU1976 ratios which could be interpreted as either greater than or less than 0.5, if the analytical uncertainties of both analyses in this ratio are rigorously applied. Screens of two wells intercept the tail end of the spike because both their uncertainty-adjusted TU1988/TU1976 ratios range from 0.29 to 0.41.Carbon-14 activity for individual wells varied by no more than 6 Per cent Modern Carbon (PMC) between 1976 and 1988. Bomb-spike 14C is not so easily detected as tritium in passage through aquifers because the thermonuclear input of 14C into the atmosphere was much less intense (relative to pre-bomb, background levels) than that for tritium. Also, incongruent dissolution of dolomite, coupled with differing dissolution kinetics between dolomite and calcite, precipitates 14C-bearing calcite in the saturated zone. Although the chemistry of an aquifer can be reasonably characterized by a single sampling episode, the recharge rate and groundwater flow paths are best delineated from a geochemical perspective by multiple samplings in which a persistent chemical and/or isotopic tracer is sought out and repeatedly analyzed. In the Waterloo aquifer, these are tritium and Cl. The sameness of 14C activity in waters sampled 12 a apart makes this a poor candidate to use in this scheme

University of Waterloo Radiocarbon Dates I

This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Isotopic Variability in Arctic Precipitation as a Climatic Indicator

Preliminary data are examined from a project in which the variability in the isotopic composition of precipitation across northern Canada and the implications for paleoclimatic reconstruction are examined. The data set shows a geographic variability of about 6%o in isotopic composition of precipitation across the Canadian Arctic, roughly double the temporal variability seen in the ice core records from the last 10,000 years. The seasonal variability in average monthly &#x03B4;18O values from the arctic stations in 1991 was as much as 26%o. A snow and firn core collected on Bylot Island had arange of 14.8%o, compared to the range in average monthly precipitation of 25.6%o covering the same time period. This difference in the observed seasonal range of values is the result of processes operating in the snow pack, such as vapor movement and molecular diffusion, and the strategy used in sampling the core. The results indicate that a much better understanding of the geographic and seasonal variation in the &#x03B4;18O values of precipitation is required before a direct linkage between the isotope records in ice cores and global climate change can be determined. Using recently developed radiocarbon dating techniques, buried glacier ice that has been preserved in permafrost may be able to provide the greater spatial and temporal detail required. Résumé Dans le présent article, on étudie des données préliminaires d'un projet de la variation de la composition isotopique des précipitations dans le nord du Canada et où, on s'intéresse à l'applicabilité de telles mesures dans les reconstiutions paléoclimatiques. Le jeu de données indique qu'il existe une variabilité géographique de 6 %o dans la composition isotopique des précipitations à travers l'Arctique canadien, ce qui est le double environ de la variabilité temporelle observée dans le carottes de glace des derniers 10,000 ans. La variabilité saisonnière des valeurs moyennes mensuelles de 18O mesurée en 1991 à partir de stations arctiques atteint 26 %o. Une carotte de neige et de névé prélevée sur l'île Bylot a montré une fourchette de variation de 14,8 %o, à comparer avec une fourchette des variations moyennes mensuelles des précipitations de 25,6 %o pour la même période. Les différences de fourchette de valeurs saisonnières observées dépendent des processus se déroulant au sein même de la couverture neigeuse, comme les mouvements de la phase gazeuse et la diffusion moléculaire, ainsi que des techniques de prélèvement employées. Les résultats montrent qu'il faudra beaucoup améliorer notre compréhension des variations géographiques et saisonnières des valeurs de 18O des précipitations avant que l'on puisse faire un lien direct entre la variation du profil isotopique des carottes de glace et un changement climatique à l'échelle du globe. L'utilisation de techniques de datation par le radiocarbon mises au point récemment sur des glaces de glacier enfouies et préservées dans le pergélisol permettra peut-être d'atteindre la précision nécessaire dans les mesures spatiales et temporelles

Oxygen isotope exchange between sulphate and water during bacterial reduction of sulphate.

The bacterial reduction of sulphate is accompanied by oxygen isotope exchange reactions. The mechanisms were not investigated in detail but it is suggested that the formation of sulphate-enzyme complexes as intermediary reaction products are facilitating the exchange of 18O between water and sulphate. Under the experimental conditions the observed fractionation factor is close to 25&permil; at 30&deg;C and approaches 27&permil; at 17&deg;C. Extrapolated values from a field study indicate a difference of &sim; 29&permil; at &sim; 5&deg;C

New Possibilities for 14C Measurements by Liquid Scintillation Counting

From the 13th International Radiocarbon Conference held in Dubrovnik, Yugoslavia, June 20-25, 1988.Results of intercomparison tests are presented on samples analyzed using gas and liquid scintillation techniques to study the capability of the LKB Quantulus to count an organic solution used for direct absorption of CO2 and samples with low carbon content. Good agreement was obtained for small samples compared to standard sample size and for the direct absorption compared with the traditional techniques.This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202