439 research outputs found

    Simultaneous measurement of the trace elements Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum and their reference ranges by ICP-MS

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    The goal of this article was to establish reference ranges of the concentration of trace elements in human serum and to compare these results with those reported by other authors. We describe the sample preparation and measurement conditions that allow the rapid, precise, and accurate determination of Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum samples (n=110) by inductively coupled plasma-mass spectrometry (ICP-MS). Accuracy and precision were determined by analyzing three reconstituted reference serum samples by comparison with other methods and by the standard addition procedure. The advantages of the ICP-MS method include short time of analysis of the elements mentioned, low detection limit, high precision, and high accuracy. Disadventages include a high risk of contamination due to the presence of some of the elements of interest in the environment, the relatively delicate sample handling, and the high cost of the equipmen

    Einfluss des Anbausystems auf Ertrag und Gesundheit von Winterweizen

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    In a long-term trial in central Switzerland, yield and health of winter wheat was examined under organic, extensive and intensive management. In the organic cropping system, soil was ploughed and fertilised with cattle dung. In the extensive system, soil was cultivated ploughless and dung was supplemented by mineral fertiliser. Herbicides were used, but no growth regulators or fungicides. In the intensive system, soil was ploughed and manure was based on cattle dung and mineral fertiliser with 20 % more nitrogen than in the extensive system. For plant protection, herbicides, growth regulators and fungicides were used. In the period from 2004 to 2007, average winter wheat yields of the intensive and the extensive crop management system exceeded those of the organic production by 21.3 % and 5.5 % respectively. This was probably due to the higher level of fertilisation and plant protection. In 2007, a year with frequent rain during the summer, the infestation of grains with Microdochium nivale and Fusarium graminearum was lowest in the organic wheat. In consequence, its germination capacity was higher and the deoxynivalenol content was lower compared with the other systems. The increased grain infestation with F. graminearum and the higher deoxynivalenol content of wheat grains in the extensive system can be explained by the ploughless tillage, with straw from the previous maize crop remaining on the soil surface

    Concentration of 17 trace elements in serum and whole blood of plains viscachas (Lagostomus maximus) by ICP-MS, their reference ranges, and their relation to cataract

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    The reference ranges of the trace elements Al, As, Be, B, Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Li, Rb, Se, Sr, and Zn were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in sera of a group of free-ranging plains viscachas of the pampa grasslands of Argentina. The values were compared with those of a small group of captive plains viscachas of the Zurich Zoo with diabetes and bilateral cataracts. In addition, a method for digestion of whole-blood samples is described for the trace element determination. Significant differences in the concentration of trace elements in the two groups of animals are discussed. No correlation was found between the levels of selenium and of other trace elements compared to the formation of cataract

    Einfluss von Phytophthora infestans auf den Kartoffelertrag in Abhängigkeit von der Nährstoffversorgung und optimierten Kupferapplikationen

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    Late blight, caused by Phytophthora infestans is commonly thought to be the factor most limiting yield in organic potato production. However, because there is no fully effective fungicide available to control late blight, there are virtually no yield loss data available for organic farming conditions. In large-scale experiments covering 2-6 ha from 2000-2002, late blight assessments were conducted throughout the season in small sections throughout the field. The same sections were harvested, resulting in between 400 and 700 data points per experiment and year. In a second set of experiments, from 2002-2004, the interactive effects of N-availability in the soil, climatic conditions and late blight were studied in the presence and absence of copper fungicides for the mid-early main-crop potato variety Nicola. Again, late blight and yield assessments were conducted within defined sections in the field resulting in about 100 data points per experiment. In 2005 and 2006, new copper products with minimal copper contents (157g Cu/ha and applica-tion) and optimised applications using the model Bio-PhytoPRE were integrated. Depending on year and variety, between 0 and 40% of the variation in yield could be explained through late blight severity. Copper fungicides in most cases did slow down epidemics somewhat adding an average of 3 days to the growth duration. However, only 26% of the variation in yield could be attributed to disease reductions. A multi-variate model including disease reduction, growth duration and temperature sum, and soil mineral N contents for the years 2002-2004 (FINCKH et al., 2006) could explain 61% of the observed variation in yield. However, the model failed when N-supply was extremely high. In 2005-2006, without the forecasting model, copper had no significant effect on dis-ease in plots with low nutrient availability while minimised applications combined with the forecasting model resulted in more reliable disease reductions even under low nutrient conditions. A reduction of the current maximally allowed Copper inputs from 3 kg to 1.5 kg per ha and year should thus be considered. Overall yield gains through copper applications were only 10% on average. The economic usefulness of copper applications needs to be scrutinised before recommending its use. The implications of the results on the management of organic potatoes will be discussed

    Discrete Kinetic Models from Funneled Energy Landscape Simulations

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    A general method for facilitating the interpretation of computer simulations of protein folding with minimally frustrated energy landscapes is detailed and applied to a designed ankyrin repeat protein (4ANK). In the method, groups of residues are assigned to foldons and these foldons are used to map the conformational space of the protein onto a set of discrete macrobasins. The free energies of the individual macrobasins are then calculated, informing practical kinetic analysis. Two simple assumptions about the universality of the rate for downhill transitions between macrobasins and the natural local connectivity between macrobasins lead to a scheme for predicting overall folding and unfolding rates, generating chevron plots under varying thermodynamic conditions, and inferring dominant kinetic folding pathways. To illustrate the approach, free energies of macrobasins were calculated from biased simulations of a non-additive structure-based model using two structurally motivated foldon definitions at the full and half ankyrin repeat resolutions. The calculated chevrons have features consistent with those measured in stopped flow chemical denaturation experiments. The dominant inferred folding pathway has an “inside-out”, nucleation-propagation like character

    Evaluation of a high-resolution regional climate simulation over Greenland

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    A simulation of the 1991 summer has been performed over south Greenland with a coupled atmosphere–snow regional climate model (RCM) forced by the ECMWF re-analysis. The simulation is evaluated with in-situ coastal and ice-sheet atmospheric and glaciological observations. Modelled air temperature, specific humidity, wind speed and radiative fluxes are in good agreement with the available observations, although uncertainties in the radiative transfer scheme need further investigation to improve the model’s performance. In the sub-surface snow-ice model, surface albedo is calculated from the simulated snow grain shape and size, snow depth, meltwater accumulation, cloudiness and ice albedo. The use of snow metamorphism processes allows a realistic modelling of the temporal variations in the surface albedo during both melting periods and accumulation events. Concerning the surface albedo, the main finding is that an accurate albedo simulation during the melting season strongly depends on a proper initialization of the surface conditions which mainly result from winter accumulation processes. Furthermore, in a sensitivity experiment with a constant 0.8 albedo over the whole ice sheet, the average amount of melt decreased by more than 60%, which highlights the importance of a correctly simulated surface albedo. The use of this coupled atmosphere–snow RCM offers new perspectives in the study of the Greenland surface mass balance due to the represented feedback between the surface climate and the surface albedo, which is the most sensitive parameter in energy-balance-based ablation calculations.Peer reviewe

    Last Men Standing: Chlamydatus Portraits and Public Life in Late Antique Corinth

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    Notable among the marble sculptures excavated at Corinth are seven portraits of men wearing the long chlamys of Late Antique imperial office. This unusual costume, contemporary portrait heads, and inscribed statue bases all help confirm that new public statuary was created and erected at Corinth during the 4th and 5th centuries. These chlamydatus portraits, published together here for the first time, are likely to represent the Governor of Achaia in his capital city, in the company of local benefactors. Among the last works of the ancient sculptural tradition, they form a valuable source of information on public life in Late Antique Corinth

    Marketing as a means to transformative social conflict resolution: lessons from transitioning war economies and the Colombian coffee marketing system

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    Social conflicts are ubiquitous to the human condition and occur throughout markets, marketing processes, and marketing systems.When unchecked or unmitigated, social conflict can have devastating consequences for consumers, marketers, and societies, especially when conflict escalates to war. In this article, the authors offer a systemic analysis of the Colombian war economy, with its conflicted shadow and coping markets, to show how a growing network of fair-trade coffee actors has played a key role in transitioning the country’s war economy into a peace economy. They particularly draw attention to the sources of conflict in this market and highlight four transition mechanisms — i.e., empowerment, communication, community building and regulation — through which marketers can contribute to peacemaking and thus produce mutually beneficial outcomes for consumers and society. The article concludes with a discussion of implications for marketing theory, practice, and public policy

    The effect of high altitude (2500 m) on incremental cycling exercise in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: a randomised controlled cross-over trial

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    Objective: To investigate the effect of a daylong exposure to high altitude on peak exercise capacity and safety in stable patients with pulmonary arterial and chronic thromboembolic pulmonary hypertension (PAH/CTEPH). Methods: In a randomised controlled cross-over trial, stable patients with PAH or distal CTEPH without resting hypoxemia at low altitude performed two incremental exercise tests to exhaustion, one after 3–5 h at high (2500 m) and one at low altitude (470 m). Results: In 27 patients with PAH/CTEPH (44% women, 61±14 y), maximal work-rate was 110±64 watts at 2500 m and 123±64 watts at 470 m (−11%, 95%CI: −16 to −11, p<0.001). SpO2_{2}and PaO2_{2}at end-exercise were 83±6% versus 91±6% and 6.1±1.9 kPa versus 8.6±1.9 kPa (−8%; −29%; both p<0.001) at 2500 m versus 470 m, respectively. Maximal oxygen uptake at high altitude was 17.8±7.5 L·min1^{−1}·kg1^{−1} versus 20±7.4 L·min1^{−1}·kg1^{−1}at low altitude (−11%, p<0.001). At end-exercise, the ventilatory equivalent for CO2_{2}was 43±9 at 2500 m versus 39±9 at 470 m (+9%, 95%CI: 2 to 6; p=0.002). No adverse events occurred during or after exercise. Conclusion: Among predominantly low-risk patients with stable PAH/CTEPH, cycling exercise during the first day at 2500 m was well tolerated, but peak exercise capacity, blood oxygenation and ventilatory efficiency were lower compared to 470 m
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