2,444 research outputs found

    Paleolimnology of ancient Lake Mätäjärvi

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    Comparison of the levels of organic, elemental and inorganic carbon in particulate matter in six urban environments in Europe

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    International audienceA series of 7-week sampling campaigns were conducted in urban background sites in the six European cities as follows: Duisburg 4 October?21 November 2002 (autumn), Prague 29 November 2002?16 January 2003 (winter), Amsterdam 24 January?13 March 2003 (winter), Helsinki 21 March?12 May 2003 (spring), Barcelona 28 March?19 May 2003 (spring) and Athens 2 June?21 July 2003 (summer). The campaigns were scheduled to include seasons of local public health concern due to high PM concentrations or findings in previously conducted epidemiological studies. Aerosol samples were collected in parallel with two identical virtual impactors (VI), which divide air PM into two size fractions, PM2.5 and PM2.5-10. The filter samples were analysed with a microbalance, an energy dispersive X-ray fluorescence (ED-XRF), an ion chromatograph (IC) and a thermo-optical carbon analyser (TOA). The PM2.5 and PM2.5-10 campaign means ranged 8.3?29.6 µg m-3 and 5.4?28.7 µg m-3, respectively. The ''wet and cool'' seasons favoured low coarse PM concentration and high fine PM concentration, whereas the spring and summer led to low fine and high coarse PM concentrations. The contribution of particulate organic matter (POM) to PM2.5-10 was highest (27%) in Prague and the lowest (10%) in Barcelona, while those to PM2.5 were generally higher, ranging from 21% in Barcelona to 54% in Prague. The contribution of elemental carbon (EC) to PM2.5-10 were relatively low (1?6%) in all the six European cities but it contributed somewhat higher (5?9%) to PM2.5. The differences are most likely due to variable contributions of local emission sources and seasonal factors such as domestic heating, vehicle exhausts and photochemical reactions. Carbonate, which interferes with carbon analysis by evolving stage at 900°C, was detected in the coarse particles of Athens and Barcelona and it could be separated reliably from OC by a simple integrating method. The calcium carbonate in Athens and Barcelona accounted for 56% and 11% of coarse PM masses, respectively. Carbonate was not found in other cities or in PM2.5. The mean PM2.5 mass portions of five OC thermal fractions (OC1, OC2, OC3, OC4 and OCP) varied in the range 26?33%, 6?10%, 7?10%, 9?22% and 29?50%, respectively, in six cities. The differences in the mass portion profiles were relatively small between the cities

    Organic, elemental and inorganic carbon in particulate matter of six urban environments in Europe

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    International audienceA series of 7-week sampling campaigns were conducted in urban background sites of six European cities as follows: Duisburg (autumn), Prague (winter), Amsterdam (winter), Helsinki (spring), Barcelona (spring) and Athens (summer). The campaigns were scheduled to include seasons of local public health concern due to high particulate concentrations or findings in previously conducted epidemiological studies. Aerosol samples were collected in parallel with two identical virtual impactors that divide air particles into fine (PM2.5) and coarse (PM2.5-10) size ranges. From the collected filter samples, elemental (EC) and organic (OC) carbon contents were analysed with a thermal-optical carbon analyser (TOA); total Ca, Ti, Fe, Si, Al and K by energy dispersive X-ray fluorescence (ED-XRF); As, Cu, Ni, V, and Zn by inductively coupled plasma mass spectrometry (ICP/MS); Ca2+, succinate, malonate and oxalate by ion chromatography (IC); and the sum of levoglucosan+galactosan+mannosan (?MA) by liquid chromatography mass spectrometry (LC/MS). The campaign means of PM2.5 and PM2.5-10 were 8.3-29.6 µg m-3 and 5.4-28.7 µg m-3, respectively. The contribution of particulate organic matter (POM) to PM2.5 ranged from 21% in Barcelona to 54% in Prague, while that to PM2.5-10 ranged from 10% in Barcelona to 27% in Prague. The contribution of EC was higher to PM2.5 (5-9%) than to PM2.5-10 (1-6%) in all the six campaigns. Carbonate (C(CO3), that interferes with the TOA analysis, was detected in PM2.5-10 of Athens and Barcelona but not elsewhere. It was subtracted from the OC by a simple integration method that was validated. The CaCO3 accounted for 55% and 11% of PM2.5-10 in Athens and Barcelona, respectively. It was anticipated that combustion emissions from vehicle engines affected the POM content in PM2.5 of all the six sampling campaigns, but a comparison of mass concentration ratios of the selected inorganic and organic tracers of common sources of organic material to POM suggested also interesting differences in source dominance during the campaign periods: Prague (biomass and coal combustion), Barcelona (fuel oil combustion, secondary photochemical organics) and Athens (secondary photochemical organics). The on-going toxicological studies will clarify the health significance of these findings

    Metabarcoding successfully tracks temporal changes in eukaryotic communities in coastal sediments

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    Metabarcoding is a method that combines high-throughput DNA sequencing and DNA-based identification. Previously, this method has been successfully used to target spatial variation of eukaryote communities in marine sediments, however, the temporal changes in these communities remain understudied. Here, we follow the temporal changes of the eukaryote communities in Baltic Sea surface sediments collected from two coastal localities during three seasons of two consecutive years. Our study reveals that the structure of the sediment eukaryotic ecosystem was primarily driven by annual and seasonal changes in prevailing environmental conditions, whereas spatial variation was a less significant factor in explaining the variance in eukaryotic communities over time. Therefore, our data suggests that shifts in regional climate regime or large-scale changes in the environment are the overdriving factors in shaping the coastal eukaryotic sediment ecosystems rather than small-scale changes in local environmental conditions or heterogeneity in ecosystem structure. More studies targeting temporal changes are needed to further understand the long-term trends in ecosystem stability and response to climate change. Furthermore, this work contributes to the recent efforts in developing metabarcoding applications for environmental biomonitoring, proving a comprehensive option for traditional monitoring approaches.Peer reviewe

    Hostility and the progression of carotid atherosclerosis

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    http://deepblue.lib.umich.edu/bitstream/2027.42/51461/1/Julkunen J, Hostility and the Progression, 1994.pd

    Primary hyperparathyroidism caused by bilateral parathyroid cystic carcinoma in a cat

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    Abstract Case summary A 16-year-old neutered female Korat cat presented with chronic vomiting, mild azotaemia and mild hypercalcaemia. Physical examination revealed bilateral palpable masses on each side of the trachea. Laboratory results were consistent with primary hyperparathyroidism, diagnostic imaging findings with cystic thyroid or parathyroid masses, and fine-needle aspiration cytology with thyroid hyperplasia or adenoma. In order to confirm whether one or two of the masses were the cause of the hyperparathyroidism, cystic fluid was aspirated from both for parathyroid hormone concentration measurement. The concentration was shown to exceed that of the serum manyfold in both samples, confirming both masses to be functional and of parathyroid origin. A total parathyroidectomy and thyroidectomy were performed on the right side, and a subtotal thyroidectomy and a subtotal to total parathyroidectomy on the left, without any major postoperative complications. Histopathology was consistent with bilateral parathyroid carcinoma. Relevance and novel information To our knowledge, this report is the first to describe a rare case of bilateral parathyroid cystic carcinoma in a cat. It highlights the usefulness of determining parathyroid hormone concentration in the cystic fluid of a suspected neoplastic parathyroid mass preoperatively. It also demonstrates that it may be possible to remove most of the cervical parathyroid and thyroid tissue of a cat without causing any clinically relevant hypocalcaemia or iatrogenic hypothyroidism. However, serum concentrations of ionised calcium, thyroxine and creatinine should be closely monitored in the postoperative period in order to detect and control possible complications.Peer reviewe
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