Beef cattle production is highly criticized because of the high use of land and water resources, and by the pollution (e.g., the gas methane in a cow’s breath and nitrogen in urine) produced by cows fed in feedlots. In contrast to feedlots diets and grasses, some plants (e.g., legumes) contain bioactive compounds (condensed tannins) that reduce pollution and enhance animal nutrition. In my research, I observed that cows grazing a tannin-containing legume (birdsfoot trefoil; BFT) had methane emissions similar to cows fed a feedlot ration with comparable weight gains. Cows in the BFT treatment gained more weight than cows grazing grass (meadow brome) or a legume without tannins (cicer milkvetch). Additionally, I estimated the potential areas in the state of Utah than can sustain birdsfoot trefoil production, with 412,250 ha distributed mostly in the Box elder, Cache, Millard and Sanpete counties. Thus, feeding tannin-containing legumes to cows is a viable alternative to feedlot rations, with greater levels of productivity than other pasture-based systems, which can lead to a more sustainable production of beef.

Greenhouse gases (GHGs) are a major global environmental concern, because their concentrations have continuously increased over the past few centuries, due to global population growth, fossil fuel dependency, and the Industrial Revolution. Since these gases are naturally occurring phenomena, they will never be completely eliminated. Efforts to reduce them span numerous scientific attempts, with minimal improvements in reducing their atmospheric concentrations. In agricultural land practices, greenhouse gases are common byproducts that affect the atmosphere and, potentially, the groundwater where livestock and fertilizers are key contributors. Little is known about the fate of such greenhouse gases in dissolved form, known as indirect greenhouse gases, especially (CH4 and N2O) in karst landscapes. At Crumps Cave, indirect greenhouse gases were analyzed for seasonal changes along with other geochemistry parameters to identify if anthropogenic land use effected greenhouse gases production in the epikarst and bedrock. This study revealed that CO2 flux is mainly controlled by natural vegetation and seasonal influences. In contrast, CH4 is produced and consumed continuously in the epikarst and bedrock, where decay of organic matter is the primary driver for seasonal change and temperature has little effect on methanogens and methanotrophs survival, because of their ability of adaptation to the environment. N2O, via the nitrogen cycle in which nitrification/denitrification occurs, is directly affected by land use during fertilizer application and crop rotation. Nitrates from the surface provide a nitrogen source for denitrification to occur and produce elevated N2O in the groundwater system, because residence time is decreased and dissolved oxygen is elevated. Indirect greenhouse gases are linked to karst groundwater systems, where they may be transported and stored in karst aquifers under agricultural land use practices through complex interactions of groundwater recharge, microbial activity, and seasonal land use variability.

Nitrous oxide (N2O) is an inexpensive and readily available non-toxic rocket motor oxidizer. It is the most commonly used oxidizer for hybrid bipropellant rocket systems, and several bipropellant liquid rocket designs have also used nitrous oxide. In liquid form, N2O is highly stable, but in vapor form it has the potential to decompose exothermically, releasing up to 1865 Joules per gram of vapor as it dissociates into nitrogen and oxygen. Consequently, it has long been considered as a potential "green" replacement for existing highly toxic and dangerous monopropellants. This project investigates the feasibility of using the nitrous oxide decomposition reaction as a monopropellant energy source for igniting liquid bipropellant and hybrid rockets that already use nitrous oxide as the primary oxidizer. Because nitrous oxide is such a stable propellant, the energy barrier to dissociation is quite high; normal thermal decomposition of the vapor phase does not occur until temperatures are above 800 C. The use of a ruthenium catalyst decreases the activation energy for this reaction to allow rapid decomposition below 400 C. This research investigates the design for a prototype device that channels the energy of dissociation to ignite a laboratory scale hybrid rocket motor.

No description available.

No description available.

<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.