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Evolution of Radiocarbon in a Sandy Aquifer Across Large Temporal and Spatial Scales: Case Study from Southern Poland
- M Dulinski, K Rozanski, T Kuc, Z Gorczyca, J Kania, M Kapusta
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- Journal:
- Radiocarbon / Volume 55 / Issue 2 / 2013
- Published online by Cambridge University Press:
- 09 February 2016, pp. 905-919
- Print publication:
- 2013
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We present the results of a comprehensive study aimed at tracing the evolution of carbon isotopic composition of the TDIC (total dissolved inorganic carbon) reservoir from the unsaturated zone down to the discharge area, in a sandy aquifer near Kraków, southern Poland. A multilevel well penetrating the unsaturated zone in the study area was equipped with horizontally mounted lysimeters with ceramic suction cups to collect samples of pore water and metal probes to collect soil air. Strong seasonal fluctuations were observed of soil pCO2 extending down to the water table, coupled with distinct, well-defined depth profiles of δ13CTDIC reaching approximately −10′ at 8 m depth and almost constant radiocarbon content in the TDIC pool, comparable to 14CO2 levels in the local atmosphere. Simple models (closed/open system) do not account for the observed depth variations of carbon isotopic composition of the TDIC pool. This suggests that the TDIC reservoir of pore waters is evolving under conditions gradually changing from an open towards a closed system. In order to explain 13C and 14C content of dissolved carbonates in groundwater in the recharge area of the studied aquifer, additional sources of carbon in the system are considered, such as organic matter decomposition accompanied by reduction of dissolved nitrates and sulfates. The piston-flow l4C ages of groundwater in the confined part of the studied system were calculated using 2 approaches: 1) the correction model proposed by Fontes and Garnier (1979) was used to calculate groundwater ages, utilizing the chemical and carbon isotopic data available for the sampled wells; and 2) inverse geochemical modeling was performed for selected pairs of wells using NETHPATH code. The calculated 14C ages of groundwater range from approximately 0.6 to 37.5 ka BP. Although both methods appeared to be in a broad agreement, NETHPATH calculations revealed that isotopic exchange processes between TDIC pool and solid carbonates present in relatively small amounts in the aquifer matrix play an important role in controlling the 13C and 14C signatures of the dissolved carbonate species in groundwater and should be taken into account when 14C ages are calculated.
Concentration of Radiocarbon in Soil-Respired CO2 Flux: Data-Model Comparison for Three Different Ecosystems in Southern Poland
- Z Gorczyca, T Kuc, K Rozanski
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- Journal:
- Radiocarbon / Volume 55 / Issue 3 / 2013
- Published online by Cambridge University Press:
- 09 February 2016, pp. 1521-1532
- Print publication:
- 2013
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We report and compare the results of long-term observations (1998–2006) of monthly mean soil CO2 fluxes and their carbon isotope composition, carried out at 3 sites with contrasting characteristics: 1) a grassland site located in the urban area of Krakow, southern Poland, which was exposed to anthropogenic impact for more than a century; 2) a mixed forest site; and 3) cultivated agricultural field site. A closed-chamber, dynamic sampling system was used to collect monthly cumulative samples of soil-respired CO2. The CO2 collected at the mixed forest site was enriched in 14C with respect to European free-atmosphere continental 14CO2 background (high-altitude station Jungfraujoch in Swiss Alps) by approximately 40%, while the urban site revealed 14C depletion by ∼30% against the same reference. The Δ14C values observed at the agricultural site were lying in between, clustering along the regional reference atmospheric Δ14CO2 trend curve. The Δ14C values of soil-respired CO2 at the urban site turned out to be indistinguishable from the Δ14CO2 values in the local atmosphere. For the estimation of mean turnover time of soil carbon for each of the monitored sites, we used a multicompartment model (MCM) accounting for input of carbon to the soil profile via deposition of fresh organic matter, as well as 3 different sources of CO2 in the soil profile: 1) root respiration; 2) “fast”; and 3) “slow” pools of soil carbon. The estimated mean turnover time of carbon in the “fast” carbon pool was ∼14 yr for both urban grassland and mixed forest sites, and ∼22 yr for the cultivated agricultural field. From the observed differences in Δ14C values of the measured fluxes of soil-respired CO2, we conclude that 14C content of the biogenic component in the local atmospheric CO2 is site-specific and may differ significantly from the regional atmospheric background Δ14CO2 value. Therefore, the assumption widely used in 14C-based assessments of the fossil-fuel contribution local atmospheric CO2 load, stating that 14C concentration in the biogenic CO2 component is equal to that of regional atmospheric reference value, needs to be carefully evaluated on a case-by-case basis.
Radiocarbon Dating of Pleistocene Fauna and Flora from Starunia, SW Ukraine
- T Kuc, K Różański, M J Kotarba, T Goslar, H Kubiak
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- Journal:
- Radiocarbon / Volume 54 / Issue 1 / 2012
- Published online by Cambridge University Press:
- 18 July 2016, pp. 123-136
- Print publication:
- 2012
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New attempts arc presented to determine the age of large Pleistocene mammals excavated at Starunia, ∼130 km southeast of Lviv, Ukraine. This remarkable discovery made at the beginning of the 20th century included a complete carcass of woolly rhinoceros (No. 2), fragments of 3 woolly rhinoceroses (Nos. 1, 3, and 4) and remnants of numerous specimens of other fossil fauna and flora. Although attempts to date paleontological findings from Starunia site go back to the early 1970s, the results obtained before 2006 arc somewhat misleading, mostly due to unresolved contamination problems. Comprehensive cleaning of the samples adopted in the framework of this study was aimed at removal of 2 potential sources of contamination: (i) radiocarbon-free hydrocarbons abundant at the burial site; and (ii) allochthonous organic materials containing contemporary carbon that were used in the past during preservation of the dated specimens. Two types of samples have been analyzed for their 14C content in the framework of the present study: (i) fragments of bones and teeth collected from specimens stored or exposed in the Natural History museums in Lviv and Kraków; and (ii) samples of terrestrial macrofossils retrieved from sediment cores obtained during the 2007–2008 field campaigns in the Starunia area. 14C analyses of collagen were supplemented by measurements of its elemental C/N ratio and 13C/12C and 15N/14N isotope ratios. Three 14C dates obtained for rhinoceros No. 2 span the age range from 35.3 to 40.0 ka BP, in agreement with the minimum age estimated from macrofossils. The mean value of 37.7 ± 1.7 ka BP falls in the range of ages reported for big Pleistocene mammals from other locations in Europe. The bones of rhinoceros No. 3, which were found in close vicinity to those of rhinoceros No. 2, reveal a 14C age of 36.7 ± 0.6 ka BP. The δ15N and δ13C values obtained for collagen extracted from bones and teeth belonging to rhinoceroses Nos. 1, 2, and 3 are in a broad agreement with analogous literature data for large Pleistocene mammals found in other sites in Europe, North America, and Siberia.
Two Decades of Regular Observations of 14CO2 and 13CO2 Content in Atmospheric Carbon Dioxide in Central Europe: Long-Term Changes of Regional Anthropogenic Fossil CO2 Emissions
- T Kuc, K Rozanski, M Zimnoch, J Necki, L Chmura, D Jelen
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- Journal:
- Radiocarbon / Volume 49 / Issue 2 / 2007
- Published online by Cambridge University Press:
- 18 July 2016, pp. 807-816
- Print publication:
- 2007
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Time series are presented of radiocarbon and 13C contents in atmospheric carbon dioxide over eastern Europe (southern Poland), covering the periods 1983–1994 and 2000–2004. The carbon isotope composition was measured in biweekly composite samples of atmospheric CO2, collected about 20 m above the local ground level. The data for 2 observational sites are presented: i) city of Kraków (50°04′N, 19°55′E; 220 m asl; for 1983–1994 and 2000–2004); and ii) Kasprowy Wierch, Tatra Mountains (49°14′N, 19°56′E; 1989 m asl; for 2000–2004). The latter site is considered a regional reference station, relatively free of anthropogenic influences. During the period 1983–1994, observations in the Kraków area revealed a gradual decrease of 14C content with a broad minimum around 1991 and a small increase by about 10% in the subsequent years. δ13C also changes with time, showing a decreasing trend from approximately −9.6% in 1983, with a slope of −0.02%/yr. The observed trends for both isotopes coincide well with a substantial reduction of coal consumption in Poland and partial replacement of coal by natural gas, especially in urban regions. After 2000, the δ13C slightly increases, reaching a mean value of −10% in 2004, while Δ14C is below the reference level by ∼3.5%. Observations at Kasprowy Wierch (regional reference station) also reflect a diminishing input of fossil carbon into the regional atmosphere. The fossil component in atmospheric CO2, calculated with the aid of 14C data available for the 2 study periods, shows a reduction of anthropogenic input by a factor of 2, which is confirmed by annual statistics of coal consumption.
Mental stress and the induction of silent myocardial ischemia in patients with coronary artery disease
- from Section 2 - Psychophysiological processes in disease
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- By A. Rozanski, University of California at Los Angeles School of Medicine, C. N. Bairey, University of California at Los Angeles School of Medicine, D. S. Krantz, University of California at Los Angeles School of Medicine, J. Friedman, University of California at Los Angeles School of Medicine, K. J. Resser, University of California at Los Angeles School of Medicine, M. Morell, University of California at Los Angeles School of Medicine, S. Hilton-Chalfen, University of California at Los Angeles School of Medicine, L. Hestrin, University of California at Los Angeles School of Medicine, J. Bietendorf, University of California at Los Angeles School of Medicine, D. S. Berman, University of California at Los Angeles
- Edited by Andrew Steptoe, St George's Hospital Medical School, University of London, Jane Wardle, Imperial Cancer Research Fund, London
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- Book:
- Psychosocial Processes and Health
- Published online:
- 05 August 2016
- Print publication:
- 24 November 1994, pp 147-165
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Summary
Abstract
To assess the causal relation between acute mental stress and myocardial ischemia, we evaluated cardiac function in selected patients during a series of mental tasks (arithmetic, the Stroop color-word task, simulated public speaking, and reading) and compared the responses with those induced by exercise. Thirty-nine patients with coronary artery disease and 12 controls were studied by radionuclide ventriculography.
Of the patients with coronary artery disease, 23 (59 percent) had wall-motion abnormalities during periods of mental stress and 14 (36 percent) had a fall in ejection fraction of more than 5 percentage points. Ischemia induced by mental stress was symptomatically “silent” in 19 of the 23 patients with wall-motion abnormalities (83 percent) and occurred at lower heart rates than exerciseinduced ischemia (P<0.05). In contrast, we observed comparable elevations in arterial pressure during ischemia induced by mental stress and ischemia induced by exercise. A personally relevant, emotionally arousing speaking task induced more frequent and greater regional wall-motion abnormalities than did less specific cognitive tasks causing mental stress (P < 0.05). The magnitude of cardiac dysfunction induced by the speaking task was similar to that induced by exercise.
Personally relevant mental stress may be an important precipitant of myocardial ischemia - often silent - in patients with coronary artery disease. Further examination of the pathophysiologic mechanisms responsible for myocardial ischemia induced by mental stress could have important implications for the treatment of transient myocardial ischemia. (N Engl J Med 1988; 318:1005-12.)
Recent research indicates that transient myocardial ischemia is common in patients with coronary artery disease. It usually occurs without symptoms, at low heart rates, and has a circadian rhythm that parallels changes in heart rate, blood, pressure, and the release of catecholamines. Other evidence suggests that mental stress - like physical stress - may be associated with myocardial ischemia. It is currently unknown whether ischemia is a direct consequence of mental activities or a spontaneous or independent phenomenon. Laboratory studies involving the provocation of myocardial ischemia by mental stress are needed to confirm such a causal relation.
Studies involving positron-emission tomography have demonstrated that a wide variety of physiologic stimuli, including physical exercise, exposure to cold temperature, smoking, and nonspecific forms of mental stress, can induce transient ischemia in selected patients with coronary artery disease.