Mediated Recognition and the Quest for a Common Rational Field of Discussion in Three Early Medieval Dialogues

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Mitigating agricultural nitrogen load with constructed ponds in northern latitudes : A field study on sedimental denitrification rates

Constructed agricultural ponds and wetlands can reduce nitrogen loading from agriculture especially in areas where warm climate predominates. However, in cold climate temperature-dependency of microbiological processes have raised the question about the applicability of constructed wetlands in N removal. We measured in situ denitrification rates in a constructed agricultural pond using N-15-isotope pairing technique at ambient light and temperature throughout a year as well as diurnally. The field IPT measurements were combined with a wide set of potentially important explanatory data, including air temperature, photosynthetically active radiation, precipitation, discharge, nitrate plus other water quality variables, sediment temperature, oxygen concentration and penetration depth, diffusive oxygen uptake and sediment organic carbon. Denitrification varied, on average, diurnally between 12 and 314 mu mol N m(-2) h(-1) and seasonally between 0 and 12409 mu mol m(-2) h(-1). Light and oxygen regulated the diel variation of denitrification, but seasonally denitrification was governed by a combination of temperature, oxygen and turbidity. The results indicated that the real N removal rate might be 30-35% higher than the measured daytime rates, suggesting that neglecting the diel variation of denitrification we may underestimate N removal capacity of shallow sediments. We conclude, that by following recommended wetland:catchment - size ratios, boreal agricultural ponds can efficiently remove nitrogen by denitrification in summer and in autumn, while in winter and in spring the contribution of denitrification might be negligible relative to the loading, especially with short residence time.Peer reviewe

Organic carbon causes interference to nitrate and nitrite measurements by UV/Vis spectrometers : The importance of local calibration

Compared with sporadic conventional watersampling, continuous water-quality monitoring with opti-cal sensors has improved our understanding of freshwaterdynamics. The basic principle in photometric measure-ments is the incident light at a given wavelength that iseither reflected, scattered, or transmitted in the body ofwater. Here, we discuss the transmittance measurements.The amount of transmittance is inversely proportional tothe concentration of the substance measured. However, thetransmittance is subject to interference, because it can beaffected by factors other than the substance targeted in thewater. In this study, interference with the UV/Vis sensornitrate plus nitrite measurements caused by organic carbonwas evaluated. Total or dissolved organic carbon as well asnitrate plus nitrite concentrations were measured in variousboreal waters with two UV/Vis sensors (5-mm and 35-mmpathlengths), using conventional laboratory analysis re-sults as references. Organic carbon increased the sensornitrate plus nitrite results, not only in waters with highorganic carbon concentrations, but also at the lower con-centrations (< 10 mg C L−1) typical of boreal stream, river,and lake waters. Our results demonstrated that local cali-bration with multiple linear regression, including bothnitrate plus nitrite and dissolved organic carbon, can cor-rect the error caused by organic carbon. However, high-frequency optical sensors continue to be excellent tools forenvironmental monitoring when they are properly calibrat-ed for the local water matrix.Peer reviewe

Effects of break crops on yield and grain protein concentration of barley in a Boreal climate

Rotation with dicotyledonous crops to break cereal monoculture has proven to be beneficial to successive cereals. In two fields where the soil had been subjected to prolonged, continuous cereal production, two 3-year rotation trials were established. In the first year, faba bean, turnip rape and barley were grown, as first crops, in large blocks and their residues tilled into the soil after harvest. In the following year, barley, buckwheat, caraway, faba bean, hemp and white lupin were sown, as second crops, in each block and incorporated either at flowering stage (except barley) or after harvest. In the third year, barley was grown in all plots and its yield and grain protein concentration were determined. Mineral N in the plough layer was determined two months after incorporation of crops and again before sowing barley in the following year. The effect of faba bean and turnip rape on improving barley yields and grain protein concentration was still detectable two years after they were grown. The yield response of barley was not sensitive to the growth stage of second crops when they were incorporated, but was to different second crops, showing clear benefits averaging 6-7% after white lupin, faba bean and hemp but no benefit from caraway or buckwheat. The effect of increased N in the plough layer derived from rotation crops on barley yields was minor. Incorporation of plants at flowering stage slightly increased third-year barley grain protein concentration but posed a great potential for N loss compared with incorporation of crop residues after harvest, showing the value of either delayed incorporation or using catch crops.Peer reviewe

Truncated HSPB1 causes axonal neuropathy and impairs tolerance to unfolded protein stress

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Antagonism of peripheral opioid receptors by methylnaltrexone does not prevent morphine tolerance in rats

Opioids are effective analgesics in the management of severe pain. However, tolerance, leading to dose escalation and adverse effects are significant limiting factors in their use. The role of peripheral opioid receptors in analgesia has been discussed especially under inflammatory conditions. The results from pharmacological and conditional knockout studies together do not provide a clear picture of the contribution of peripheral opioid receptors on antinociceptive tolerance and this needs to be evaluated. Therefore, we studied whether the peripherally restricted opioid receptor antagonist, methylnaltrexone (MNTX), could prevent morphine tolerance without attenuating the antinociceptive effect of morphine. Male Sprague-Dawley rats were treated for 7 days with increasing subcutaneous doses of morphine (5-30 mg/kg) and were coadministered saline, MNTX (0.5 or 2 mg/kg), or naltrexone (NTX; 2 mg/kg). Nociception was assessed with tail-flick, hotplate, and von Frey tests. Morphine, MNTX, and NTX concentrations in the plasma, brain, and spinal cord were measured by liquid chromatography-tandem mass spectrometry. In acute coadministration, NTX, but not MNTX, abolished the acute antinociceptive effects of morphine in all nociceptive tests. The antinociceptive tolerance after repeated morphine administration was also prevented by NTX but not by MNTX. MNTX penetrated to the spinal cord and the brain to some extent after repeated administration. The results do not support the use of MNTX for preventing opioid tolerance and also suggest that morphine tolerance is mediated by central rather than peripheral opioid receptors in the rat.Peer reviewe