112 research outputs found

    A preliminary assessment of age at death determination using the nuclear weapons testing 14C activity of dentine and enamel

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    Calibration (using CALIBomb) of radiocarbon measurements made on the enamel of human teeth from people born during the nuclear era typically produce 2 possible age ranges that potentially reflect the period of tooth formation. These ranges correspond to periods before and after the 1963 atmospheric 14C maximum. Further measurements made on the collagen component of the combined dentine and cementum from the roots of the same teeth enable the appropriate age range to be selected. Using this range and the formation times for individual teeth, we estimated the year of birth of the individuals and compared these to the known dates of birth. The results were relatively accurate and confirmed those of a previous study by another research group. The present study demonstrates that it is possible to produce a good estimate of the year of birth from a single tooth

    Humics - their history in the radiocarbon inter-comparisons studies

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    Over the past 30 years, the format of the radiocarbon (14C) intercomparison studies has changed, however, the selection of sample types used in these studies has remained constantā€”namely, natural and routinely dated materials that could subsequently be used as in-house reference materials. One such material is peat which has been used 12 times, starting with the ICS in 1988. Peat from Iceland (TIRI), Ellanmore (TIRI), Letham Moss (ICS, VIRI, and SIRI), and St Bees, UK (FIRI and VIRI) have been used, as well as a near-background peat from Siberia. In the main, these peat samples have been provided as the humic acid fraction, with the main advantage being that the humic acid is extracted in solution and then precipitated (the solution phase providing the homogenisation) which is a key requirement for a reference material. In this paper, we will revisit the peat results and explore their findings. In addition, for the last 8 years, the Letham Moss sample has been used in the SUERC 14C laboratory as an in-house standard or reference material. This has resulted in several thousand measurements. Such a rich data set is explored to illustrate the benefits arising from the intercomparison program

    Race, Class, and Whiteness in Gifted and Talented Identification: A Case Study

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    What began fifteen years ago as a volunteer effort to promote desegregation via a gifted and talented magnet school has become a case study analyzing inequalities in the identification of young children for gifted and talented services. We use Cheryl Harrisā€™ (1993) argument that ā€œwhitenessā€ is a form of property that creates and maintains inequalities through the conjoining of race and class. We show how gifted and talented status meets the criteria of white property interests and is defended by recourse to law and policy. Efforts to improve identification of students for gifted services reveal that the implicit operation of these Interests is an important reason why identification practices favoring white and middle-class children have been resistant to change. Dismantling underlying white property interests in gifted and talented identification is a necessary, though not sufficient step, toward a more just educational system

    Radiocarbon releases from the 2011 Fukushima nuclear accident

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    Radiocarbon activities were measured in annual tree rings for the years 2009 to 2015 from Japanese cedar trees (Cryptomeria japonica) collected at six sites ranging from 2.5ā€“38ā€‰km northwest and north of the Fukushima Dai-ichi nuclear power plant. The 14C specific activity varied from 280.4ā€‰Bqā€‰kgāˆ’1 C in 2010 to 226.0ā€‰Bqā€‰kgāˆ’1 C in 2015. The elevated 14C activities in the 2009 and 2010 rings confirmed 14C discharges during routine reactor operations, whereas those activities that were indistinguishable from background in 2012ā€“2015 coincided with the permanent shutdown of the reactors after the accident in 2011. High-resolution 14C analysis of the 2011 ring indicated 14C releases during the Fukushima accident. The resulted 14C activity decreased with increasing distance from the plant. The maximum 14C activity released during the period of the accident was measured 42.4ā€‰Bqā€‰kgāˆ’1 C above the natural ambient 14C background. Our findings indicate that, unlike other Fukushima-derived radionuclides, the 14C released during the accident is indistinguishable from ambient background beyond the local environment (~30ā€‰km from the plant). Furthermore, the resulting dose to the local population from the excess 14C activities is negligible compared to the dose from natural/nuclear weapons sources

    Carbon isotope changes through the recent past: f14c and Ī“13c values in single barley grain from 1852 to 2020

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    Radiocarbon (F14C) and stable carbon (Ī“13C) values were measured in single grains of spring barley (Hordeum vulgare L.) from the sample archive from two adjacent sites of the Long-term Experiments (LTEs) Hoosfield Spring Barley at Rothamsted Research (Harpenden, Hertfordshire, UK), covering the growing periods (March to September) of 1852 to 2020. F14C data of the barley grain confirm that recent values are approaching and will decline below the ā€œnominalā€ F14C value of 1, tracking a similar decrease reported in other studies. Importantly, the measured Ī“13C values reveal a different temporal decline over the pre-bomb and post-bomb timescale. Detailed statistical analysis of Ī“13C data along with Ī“13C analysis of independent, archived barley mash samples, verifies and quantifies the extent and rate of this decline. Evidence presented from the barley grain and barley mash samples suggests a clear breakpoint in Ī“13C data occurring in 1995, where the rate of change alters, in that the slope in Ī“13C data for the pre-1995 period is declining at 1.4ā€° per century, and the slope in Ī“13C for the post-1995 period is declining at 3.6ā€° per century. Such a consistent shift in Ī“13C data could be used with F14C values to extend the use of the bomb peak for forensic, ecological, and environmental applications

    Combined aerobic and resistance exercise program improves task performance in patients with heart failure

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    OBJECTIVES: To assess the effects of a home-based aerobic and resistance training program on the physical function of adults with New York Heart Association (NYHA) class II and III patients and systolic heart failure (HF). DESIGN: Randomized controlled trial. SETTING: Home based. PARTICIPANTS: Stable patients (N=24; mean age, 60Ā±10y; left ventricular ejection fraction, 25%Ā±9%; 50% white; 50% women) with New York Heart Association (NYHA) classes II and III (NYHA class III, 58%) systolic heart failure (HF). INTERVENTION: A 12-week progressive home-based program of moderate-intensity aerobic and resistance exercise. Attention control wait list participants performed light stretching and flexibility exercises. MAIN OUTCOME MEASURES: A 10-item performance-based physical function measure, the Continuous Scale Physical Functional Performance test (CS-PFP10), was the major outcome variable and included specific physical activities measured in time to complete a task, weight carried during a task, and distance walked. Other measures included muscle strength, HRQOL (Minnesota Living With Heart Failure Questionnaire, Epworth Sleepiness Scale), functional capacity (Duke Activity Status Index), and disease severity (brain natriuretic peptide) levels. RESULTS: After the exercise intervention, 9 of 10 specific task activities were performed more rapidly, with increased weight carried by exercise participants compared with the attention control wait list group. Exercise participants also showed significant improvements in CS-PFP10 total score (P<.025), upper and lower muscle strength, and HRQOL (P<.001) compared with the attention control wait list group. Adherence rates were 83% and 99% for the aerobic and resistance training, respectively. CONCLUSIONS: Patients with stable HF who participate in a moderate-intensity combined aerobic and resistance exercise program may improve performance of routine physical activities of daily living by using a home-based exercise approach. Performance-based measures such as the CS-PFP10 may provide additional insights into physical function in patients with HF that more commonly used exercise tests may not identify. Early detection of subtle changes that may signal declining physical function that are amenable to intervention potentially may slow further loss of function in this patient population

    Landscapes for Neolithic People in Mainland, Orkney

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    Neolithic occupation of the Orkney Islands, in the north of Scotland, probably began in the mid fourth millennium cal BC, culminating in a range of settlements, including stone-built houses, varied stone-built tombs and two noteworthy stone circles. The environmental and landscape context of the spectacular archaeology, however, remains poorly understood. We applied the Multiple Scenario Approach (MSA) to Neolithic pollen records from Mainland, Orkney, in order to understand land cover and landscape openness across the timespan 4200ā€“2200cal BC. Interpreted within a framework provided by Bayesian chronological modelling, 406 radiocarbon dates from archaeological contexts and a further 103 from palaeoenvironmental samples provide the basis for the first detailed reconstruction of the spatio-temporal patterns of Neolithic people and their environment. Major alterations to the land cover of Mainland took place from 3400cal BC (reduction in woodland from 20% to 10%) and from 3200cal BC (increase in disturbed land from 3% to 30%). The dramatic increase in disturbed land coincided with the Grooved Ware phenomenon and the establishment of settlements at Skara Brae and Ness of Brodgar. The upturn in the signal for disturbance communities in the pollen record may indicate an increase in the amount of land used as pasture. This accords with the archaeological record, since the Neolithic Orcadian economy probably relied heavily on cattle for subsistence. By 2800cal BC in the core of the Orkney Mainland, most settlements appear to have been ending, with people dispersing into the wider landscape, as the MSA modelling indicates a maintenance of disturbed land, and indeed a subsequent slight increase, implying persistence of human activity elsewhere in Mainland. People exhausted themselves rather than their land; that and its varied resources endured, while the intensive social relationships and practices of the peak of late Neolithic Orkney could not be maintained

    When and Why? The Chronology and Context of Flint Mining at Grimeā€™s Graves, Norfolk, England

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    New radiocarbon dating and chronological modelling have refined understanding of the character and circumstances of flint mining at Grimeā€™s Graves through time. The deepest, most complex galleried shafts were worked probably from the third quarter of the 27th century cal BC and are amongst the earliest on the site. Their use ended in the decades around 2400 cal BC, although the use of simple, shallow pits in the west of the site continued for perhaps another three centuries. The final use of galleried shafts coincides with the first evidence of Beaker pottery and copper metallurgy in Britain. After a gap of around half a millennium, flint mining at Grimeā€™s Graves briefly resumed, probably from the middle of the 16th century cal BC to the middle of the 15th. These ā€˜primitiveā€™ pits, as they were termed in the inter-war period, were worked using bone tools that can be paralleled in Early Bronze Age copper mines. Finally, the scale and intensity of Middle Bronze Age middening on the site is revealed, as it occurred over a period of probably no more than a few decades in the 14th century cal BC. The possibility of connections between metalworking at Grimeā€™s Graves at this time and contemporary deposition of bronzes in the nearby Fens is discussed

    House time: Neolithic settlement development at Racot during the 5th millennium cal b.c. in the Polish lowlands

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    The settlement of Racot 18 in the western Polish lowlands is used as a case study in the investigation of continued development and expansion following initial Neolithic beginnings, and in the formal chronological modelling, in a Bayesian framework, of settlement development. The site belongs to the Late Lengyel culture of the later fifth millennium cal BC, and represents the intake of new land following earlier initial colonisation. The formally estimated chronology for the settlement suggests spans for individual house biographies from as little as a generation to over a century; distinctive substantial buildings, from late in the sequence, may have lasted longest. Racot 18 is compared to its formally modelled context of the later fifth millennium cal BC

    Using carbon isotopes to fight the rise in fraudulent whisky

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    A major threat to the Scotch whisky industry is the sale of counterfeit single malt whiskies with purported distillation years in the 19th and early- to mid-20th centuries. However, these are often much more recent spirits, distilled in the latter part of the 20th or first part of the 21st centuries. These sales impinge upon the reputation of auction houses, retailers, brand owners and distillers. The atmospheric testing of nuclear weapons in the 1950s and early 1960s has enabled a precise calibration curve to be created, however, there are several reasons why this may not be appropriate for establishing the year of whisky distillation. We have created a 14C calibration curve derived from known-age, single malt whiskies for the period 1950ā€“2015 that enables whisky distilled during the period from 1955 onwards to have the distillation year determined to within 1ā€“3 years for certain periods. However, because of the shape of the curve, two possible age ranges are often possible. The correct range can often be determined from a further plot of Ī“13C values against distillation year, which shows a trend of decreasing values through time. Several examples are given of the determination of both genuine and fake products
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