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<p>Syftet med denna deskriptiva kvalitativa intervjustudie var att beskriva barns upplevelser av lustgasbehandling. Urvalet består av sex barn i åldern sex till fjorton år som behandlats med lustgas vid procedursmärta, akut eller planerat, på barnsjukhusets akutmottagning eller allmänna specialistmottagning. Intervjuerna analyserades med kvalitativ innehållsanalys. Alla barnen upplevde annorlunda kroppskänslor eller abstrakta känslor som inte nödvändigtvis var obehagliga under lustgasbehandlingen. Samtidigt som flera av barnen beskrev en typ av frånvaro var de flesta medvetna om omgivningen och till viss del händelseförloppet. Vidare framkom att hörsel- och synintryck kunde förvrängas där ljud ibland förstärktes och kunde störa och påverka fokuseringen. Olika grader av smärta beskrevs. I barnens egen sammanfattning uttryckte fyra av barnen positiva upplevelser. Fem av barnen var positiva till att få lustgasbehandling igen om så behövdes medan ett barn svarade "kanske" och önskade i så fall en mindre mängd lustgas nästa gång. Behandlingen kan ytterligare utvecklas genom kombination med andra smärtstillande läkemedel.</p> / <p>The aim of this descriptive, qualitative interview study was to describe children´s experiences of treatment with nitrous oxide. The sample consists of six children aged six to fourteen who were treated with nitrous oxide for procedural pain, acute or planned, in the emergency room or special surgery of the Children´s hospital. The interviews were analyzed by qualitative content analysis. All children experienced different feelings in the body or intangible feelings that were not necessarily unpleasant during the treatment with nitrous oxide. Although some of the children described some kind of absence, most of them were aware of the surroundings and to some part what happened during the treatment. Further it appeared that hearing and sight impressions could be distorted and sounds were sometimes amplified and could disturb and affect the focusing. Varying degrees of pain were described. In their own summary four of the children expressed positive experiences. Five of the children were positive to receive nitrous oxide in the future if needed, while one child answered "perhaps" and in that case wanted less amount of nitrous oxide next time. The treatment could be developed further by combining with other analgesics.</p>

Invasive procedures are often painful and distressing for children and disturbing for their parents. The purpose of this study was to develop a substantive theory of parental perceptions of their school-aged child's responses to an outpatient minor surgical procedure with nitrous oxide. The sample included 22 parents of 21 children who underwent a nitrous procedure. Participants were recruited from the pediatric surgery department at a children's hospital. Semi-structured, audio-recorded interviews were conducted with each participant. Grounded theory method was used to simultaneously collect and analyze the data using the constant comparative method. The findings of the study revealed parental impressions involving a process of various emotions and behaviors. The identified process began at procedural scheduling, progressing through the procedure, and terminated going home. The core category derived from the data was Weathering the Storm before the Calm by Securing Connections. This core category describes the complexity of parental impressions and all categories subsumed by the core category. Six major categories and seven subcategories derived from the data represent parental impressions. Parental feelings of anxiety and fear arose during initial phases of the process. Parents attempted to deal with these stormy feelings in several ways. Parents experienced a sense of calmness after the procedure upon realizing their child was safe. The theme that weaves through the entire process is the parental-child connection and parental presence during the nitrous procedure. Parents also identified barriers and facilitators they faced during this process. The substantive theory that emerged provides nurses with an understanding of the stormy and subsequent calm phases parents endured. This information offers clinicians unique interventions to help parents get through this process. Future research needs extension to other settings such as radiology and other specialties such as plastic surgery and urology. Further research warrants investigating children's perceptions to their procedure with nitrous oxide.

Knowing the control of landscape position in greenhouse gas (GHG) emission from the Prairie pothole region is necessary to provide reliable emission estimates needed to formulate strategies for reducing emission from the region. Presented here are results of a study investigating the control of landscape position on the flux of nitrous oxide (N2O) and methane (CH4) from an agricultural soil. Field flux of N2O and CH4 and associated soil parameters from the Upper, Middle, Lower and Riparian slope positions were monitored from spring to fall of 2005, and spring of 2006, at the Manitoba Zero-Tillage Research Association (MTRZA) farm, 17.6km North of Brandon, MB. The field site consisted of a transect of 128 chambers segmented into the four landscape positions, with either all chambers or a subset of the chambers (32) sampled on select days. Spring thaw is an important period for annual inventory of N2O emission, thus, soil samples were also collected from the four slope positions in fall 2005, and treated in the laboratory to examine how antecedent moisture and landscape position affect the freeze-thaw emission of N2O from soil. Daily emissions of N2O and CH4 for 2005 were generally higher than for 2006, the former being a wetter year. There was high temporal variability in N2O and CH4 emission, with high fluxes associated with events like spring thaw and fertilizer application in the case of N2O, and rapid changes in soil moisture and temperature in the case of CH4. There was a high occurrence of hotspots for N2O emission at the Lower slope, associated with its high soil water-filled porosity (WFP) and carbon (C) availability. The Riparian zone was not a source of N2O emission, despite its soil WFP and organic C being comparable with the Lower slope. The hotspot for CH4 emission was located at the Riparian zone, associated with its high soil WFP and C availability. The Upper and Middle slope positions gave low emission or consumed CH4, associated with having low soil WFP and available C. This pattern in N2O and CH4 emission over the landscape was consistent with examination of entire 128 chambers on the transect or the 32 subset chambers. Significantly lowering the antecedent moisture content of soil by drying eliminated the freeze-thaw emission of N2O, despite the addition of nitrate to the soil. This was linked to drying slightly reducing the denitrifying enzyme activity (DEA) of soil. The highest and earliest freeze-thaw emission of N2O was from the Riparian zone, associated with its high antecedent moisture content, DEA and total organic C content. The addition of nitrate to soil before freezing failed to enhance freeze-thaw emission of N2O from the Upper, Middle and Lower slope positions, but increased emission three-fold for the Riparian zone. Despite the greater potential of the Riparian zone to produce N2O at thaw compared to the Upland slopes, there was no spring-thaw emission of N2O from the zone on the field. This was because this zone did not freeze over the winter, due to insulation by high and persistent snow cover, vegetation and saturated condition. The denitrifying potential and freeze-thaw N2O emission increased in going from the Upper to the Lower slope position, similar to the pattern of N2O emission observed on the field. The localization of hotspots for N2O and CH4 emission within the landscape was therefore found to be driven by soil moisture and C availability. When estimating GHG emission from soil, higher emission index for N2O and CH4 should be given to poorly-drained cropped and vegetated areas of the landscape, respectively. The high potential of the Riparian zone for spring-thaw emission of N2O should not be discountenanced when conducting annual inventory of N2O emission at the landscape scale. When fall soil moisture is high, snow cover is low, and winter temperature is very cold, freeze-thaw emission of N2O at the Riparian zones of the Prairie pothole region may be very high. / May 2007

Hemkompostering är fördelaktigt bland annat därför att det kan leda till minskade transporter av sopor och därmed koldioxidutsläpp, samt att den färdiga komposten kan användas som näringstillskott för växter. Kompostering av matavfall innebär dock en risk för bildning av metan och lustgas, vilka är starka växthusgaser. Även ammoniak, med försurande och övergödande effekter, kan släppas ut från komposten under vissa förhållanden. Det här arbetet syftar till att undersöka utsläppen av dessa ämnen, samt öka kunskapen om hur skötseln av komposten påverkar utsläppen.   Vid tre tillfällen under juni och juli 2010 utfördes mätningar på 20 komposter i Uppsala.  Temperaturen mättes i komposten, prov togs av gasen i kompostoch prover av materialet togs även för analys av vattenhalt, pH och askhalt. Hushållen förde också protokoll över sin skötsel av komposten under tiden för mätningarna. Utöver detta genomfördes en enkätstudie i vilken ett större antal komposter inkluderades, i avsikt att ge en bredare bild av hur hemkomposter i allmänhet sköts.   Gasproven analyserades i gaskromotograf, och de beräknade koncentrationerna relaterades till uppmätta temperaturer, vattenhalter, pH-värden och askhalter samt de ifyllda protokollen.   Enkätstudien visade att hemkomposter används och sköts om på mycket varierande sätt. Resultaten visade vidare att utsläppen av metan och lustgas (angivna som kvoterna CH4:CO2 respektive N2O:CO2) överlag var låga jämfört med uppmätta utsläpp i andra studier, med högre värden på omkring 2,5% endast för ett fåtal komposter. Effekterna av utsläppen av N2O beräknades till cirka 12 gånger större än de orsakade av utsläppen av CH4. Ett antydan till samband kunde ses mellan uppmätt NH3-halt och tillsatser av kväverikt kött-/fiskavfall. I övrigt kunde inga andra distinkta samband mellan skötsel och utsläpp observeras, något som skulle kunna bero på dels att endast tre mätomgångar ingår i studien och dels på att datan inhämtad från protokollen varierade i kvalitet och innehöll stora osäkerheter. / Home composting is beneficial as it can help reduce transports of household waste, and also because the mature compost can be used as a soil amendment for plants. On the other hand, composting of food waste enables formation of the potent greenhouse gases methane and nitrous oxide. It is also possible that ammonia be formed, which can have acidifying and eutrophicating effects on the environment. The aim of this study was to examine the emissions of these compounds, and if possible to gain knowledge on how the management of the compost affects these emissions.   Measurements were carried out on 20 home composts within Uppsala on three occasions during June and July in 2010. The compost temperature was measured, gas samples were taken and also samples of the material for analysis of moisture and ash content as well as pH. The households were also asked to fill in a protocol with all the compost activities performed during the period of the measurements. In addition to this, a questionnaire study was conducted in order to give an overview of how home composts in general are fed and managed.   The gas samples were analyzed in a gas chromatograph, and the obtained concentrations were then put in relation to the measured temperatures, pH, and moisture and ash contents as well as the data from the protocols.   The questionnaire study showed that home composts are used and managed in very different ways. Moreover, the results showed that the emissions of methane and nitrous oxide (given as CH4:CO2 and N2O:CO2 ratios) in general were small compared to those from other studies, with only a couple of composts with higher ratios than around 2.5%. The effects on the environment from the measured emissions of N2O were calculated to 12 times greater than those given by the emissions of CH4. Regarding ammonia, a clear connection was observed between the few elevated concentrations and additons of meaty waste rich of nitrogen. As for the greenhouse gases, no distinct correlations could be seen between how the composts were managed and the CH4:CO2 and N2O:CO2 ratios. This might be explained by the fact that only three sampling rounds were conducted, but also that the protocol information contained uncertainties and varied in quality.

Syftet med denna deskriptiva kvalitativa intervjustudie var att beskriva barns upplevelser av lustgasbehandling. Urvalet består av sex barn i åldern sex till fjorton år som behandlats med lustgas vid procedursmärta, akut eller planerat, på barnsjukhusets akutmottagning eller allmänna specialistmottagning. Intervjuerna analyserades med kvalitativ innehållsanalys. Alla barnen upplevde annorlunda kroppskänslor eller abstrakta känslor som inte nödvändigtvis var obehagliga under lustgasbehandlingen. Samtidigt som flera av barnen beskrev en typ av frånvaro var de flesta medvetna om omgivningen och till viss del händelseförloppet. Vidare framkom att hörsel- och synintryck kunde förvrängas där ljud ibland förstärktes och kunde störa och påverka fokuseringen. Olika grader av smärta beskrevs. I barnens egen sammanfattning uttryckte fyra av barnen positiva upplevelser. Fem av barnen var positiva till att få lustgasbehandling igen om så behövdes medan ett barn svarade "kanske" och önskade i så fall en mindre mängd lustgas nästa gång. Behandlingen kan ytterligare utvecklas genom kombination med andra smärtstillande läkemedel. / The aim of this descriptive, qualitative interview study was to describe children´s experiences of treatment with nitrous oxide. The sample consists of six children aged six to fourteen who were treated with nitrous oxide for procedural pain, acute or planned, in the emergency room or special surgery of the Children´s hospital. The interviews were analyzed by qualitative content analysis. All children experienced different feelings in the body or intangible feelings that were not necessarily unpleasant during the treatment with nitrous oxide. Although some of the children described some kind of absence, most of them were aware of the surroundings and to some part what happened during the treatment. Further it appeared that hearing and sight impressions could be distorted and sounds were sometimes amplified and could disturb and affect the focusing. Varying degrees of pain were described. In their own summary four of the children expressed positive experiences. Five of the children were positive to receive nitrous oxide in the future if needed, while one child answered "perhaps" and in that case wanted less amount of nitrous oxide next time. The treatment could be developed further by combining with other analgesics.

<p>Whether through sea level rise, farmland abandonment, or wetland restoration, agricultural soils in coastal areas will be inundated at increasing rates, renewing connections to sensitive surface waters and raising critical questions related to environmental tradeoffs. Wetland restoration in particular is often implemented not only to promote wildlife habitat, but also to improve water quality through nutrient removal, especially in agricultural catchments. The microbial process of denitrification is the central mechanism of nitrogen removal in wetlands and flooded soils, and can be seen as a potential environmental benefit of flooding agricultural lands. While denitrification undoubtedly can remove nitrogen from soil and surface water, higher soil moisture or flooding in wetland soils can also increase the production of greenhouse gases, specifically nitrous oxide and methane, representing a potential environmental tradeoff. Understanding the likely benefits of denitrification and the likely greenhouse gas costs of wetland restoration could help inform environmental policies concerning wetland restoration. </p> <p>Determining whether restored wetlands are larger sources of greenhouse gases compared to contrasting land use types (agriculture and forested wetlands) was the first goal of this dissertation (Chapter 2). We measured gas fluxes from soil and water to the atmosphere, and related environmental variables, in four sites over two years to estimate fluxes of the three major greenhouse gases. We found that carbon dioxide was the major contributor to the radiative balance across all sites, but that in the agricultural site and one of the forested wetland reference sites, nitrous oxide was the second most important contributor. Many studies have shown that methane is more important that nitrous oxide in most freshwater wetlands, as we found in the other forested wetland reference site and in flooded parts of the restored wetland. Overall, we did not find higher greenhouse gas fluxes in the restored wetland compared to agricultural soils or forested wetlands.</p> <p>The controls over nitrous oxide are especially complex, because it can be produced by two complementary processes, nitrification and denitrification, which generally occur under different conditions in the environment. In Chapter 3, we determined the soil and environmental factors that best predicted nitrous oxide fluxes for a subset of our data encompassing gas fluxes measured in November 2007. We found that soil temperature and soil carbon dioxide flux, along with ammonium availability and denitrification potential, were good predictors of nitrous oxide (adj R<super>2</super>=0.81). Although the nitrous oxide model did not perform as well when applied to data from another sampling period, we expect to further develop our modeling efforts to include possible non-linear temperature effects and a larger range of environmental conditions. </p> <p>In Chapter 4, we present results of a stable isotope tracer experiment to determine the relative contribution of nitrification and denitrification to nitrous oxide fluxes in these different land use types, and to determine the response of these processes to changing soil moisture. We added two forms of nitrogen-15 to intact soil cores to distinguish nitrification from denitrification, and subjected the cores to drainage or to a simulated rain event. We found that across the range of soil moisture, the fraction of nitrous oxide produced by denitrification did not change, but within each soil type there was a response to the simulated rain. In mineral soils, the nitrous oxide fraction increased with increasing soil moisture, with the highest mole fraction [N₂O/(N₂+N₂O)] in the agricultural soils, while in the organic soils there was no change or even a decrease. The fraction of nitrous oxide derived from coupled nitrification-denitrification increased with increasing soil moisture, and was much higher than that from denitrification alone in the more organic soils. This suggests that, in these saturated acid-organic soils, nitrification plays an important and underappreciated role in contributing to nitrous oxide fluxes from freshwater wetlands. The results from the laboratory experiment were consistent with patterns we saw in the field and help explain the differential contribution of nitrification and denitrification to nitrous oxide fluxes in different land use types in coastal plain wetlands of North Carolina. </p> <p>Overall, we found that both nitrification and denitrification contribute to nitrous oxide fluxes in coastal plain wetlands in North Carolina, and that nitrification is an especially important source in acid-organic soils under both field-moist and saturated conditions. Although freshwater wetlands, with an average nitrous oxide mole fraction of 0.08, are generally seen as being insignificant sources of nitrous oxide, our study sites ranged from 0.10 to 0.30, placing them closer to agricultural fields (0.38; Schlesinger 2009). Although the ecosystems in our study produced more nitrous oxide than expected for freshwater wetlands, we found no significant tradeoff between the local water quality benefits conferred by denitrification and the global greenhouse gas costs in the restored wetland. These results suggest that, from a nitrogen perspective, wetland restoration in coastal agricultural lands has a net environmental benefit.</p> / Dissertation

Nitrous oxide decomposition on Ag51, Au51, Pt22, Rh51 and Ir51 clusters representing (111) surface were studied quantum mechanically by using the method of ONIOM with high layer DFT region and low layer of molecular mechanics region utilizing universal force field (UFF). The basis set employed in the DFT calculations is the Los Alamos LANL2DZ effective core pseudo-potentials (ECP) for silver, gold, platinum, rhodium and iridium and 3-21G** for nitrogen, oxygen and hydrogen. Nitrous oxide was decomposed on the all metal surfaces investigated in this study by leaving oxygen atom adsorbed as supported by experimental findings. Activation energies of nitrous oxide decomposition on Ag51, Au51, Pt22, Rh51 and Ir51 representing (111) surface are calculated as 14.48 kcal/mol, 15.72 kcal/mol, 7.02 kcal/mol, 3.76 kcal/mol and 5.51 kcal/mol, respectively. Based on these results, decomposition of nitrous oxide occurs on Rh more easily than other metals.

El Ni&#x00F1;o is now a focal point for global climate change research, but its influence on the Western Pacific is still uncertain. Taiwan Strait is an important pathway, which connects the South China Sea and the East China Sea, and is strongly influenced by the monsoon. Generally, in winter, the strong winter monsoon brings the cold and nutrient-rich Changjiang Diluted Water¡]CDW¡^southward. While during the El Ni&#x00F1;o event, because of the weakened south wind in northern Taiwan, more cold CDW moves southward, and hence the decreased seawater temperature in spring and fall. The trend is opposite in summer. There is a high salinity signal in the seas outside of Hsin-Chu, suggesting sea water coming from the Kuroshio, which has circumvented the northeast tip of Taiwan. Meanwhile, there is a front which separates this Kuroshio water and CDW. During the El Ni&#x00F1;o, the front moves eastward, especially in summer. The salinity east of the front decreases gradually from spring to winter water, the center of upwelling located at the eastern side of the front in spring, and at or near the front from summer to winter. Furthermore, The N/P ratio of the northern Taiwan Strait water became higher after the Three Gorges Dam (TGD) became operational. The nitrous oxide (N2O) is a long-lived greenhouse gas. Unfortunately, in Taiwan, there are few data about N2O emission from rivers, lakes and coastal areas. This research also studies the N2O distribution in natural waters around Taiwan. The average surface water concentration and sea to air flux in the Taiwan Strait¡]7.81¡Ó1.28nM¡F0.28¡Ó0.38£gmol/m2/hr¡^is higher than in the South China Sea¡]SCS¡F7.55¡Ó2.45 nM¡F0.21¡Ó0.27£gmol/m2/hr¡^and the West Philippine Sea¡]WPS¡F5.3¡Ó0.62nM¡F-0.20¡Ó0.25£gmol/m2/hr¡^, which displays a rare sink signal in the world oceans. There is an N2O maximum observed around 1000m in the WPS, and another shollower one around 700m in the SCS, presumably because of the intenive upwelling and vertical mixing in the SCS basin. There are some rather high N2O concentrations (N2O>30nM) in the SCS, observed near the continental slope. We assume that these are released from sediments on the continental slope. Although the sea-to-air flux of N2O is much lower than the flux of CO2, N2O emission in the SCS contributes more than two times the greenhouse effect than CO2 does. Besides, The N2O concentration during El Ni&#x00F1;o is lower than usual, probably due to a smaller amount of the CDW. Finally, the average N2O concentrations of river and submarine groundwater discharge in Taiwan are about 32.3¡Ó43.3nM and 9.72¡Ó13.2 nM, respectively.

Plants (macrophytes) growing in lake and wetland sediments are known mediators of greenhouse gases (GHG), specifically methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O). Current studies have emphasized the potential risk of underestimation regarding emissions of plant-mediated GHGs from terrestrial systems including lakes, streams and other freshwater bodies. In order to differentiate the possible sources and sinks of atmospheric carbon and nitrogen in aquatic environments, this study aims to investigate the spatial variability of GHG fluxes in stands of common wetland macrophytes. Field samplings were carried out in the summer of 2012 where 24-hour diel measurements were conducted with the static chamber method in a boreal lake in south western Sweden. Two macrophyte communities were studied; one mixed-species stand and one species-specific stand of water horsetail (Equisetum fluviatile). Spatial variability was confirmed at several stages, both between and within stands. The species-specific stand emitted more CH4 than the mixed stand, from 0.17 to 8.99 mmol m-2 h-1, compared to 0.63 – 1.95 mmol m-2 h-1 maximum measured. Within stand variability was confirmed as variable CH4 flux per strand of E. fluviatile was established. No significant differences were observed regarding CO2 and N2O, other than weak correlation in diel patterns, e.g. daytime uptake and night time respiration/emission for both gases.