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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
391

N2O emission in a full-scale partial nitrification/anammox process.

Sambola, Alejandro January 2012 (has links)
The reduction of the emission of greenhouse gases to the atmosphere will be one of the challenges that society will have to face in the coming years. Until now, all efforts have been put in improving the properties of the discharged water in a wastewater treatment plant and the efficiency of the whole process. But little effort has been done in measuring and controlling the greenhouse gas emissions. For this reason, the production of nitrous oxide when treating wastewater has become of great concern. Several measurements in laboratory scale and full scale have been done and a wide range of results have been obtained. On the other hand, Himmerfjärden wastewater treatment plant has a deammonification plant for treating rejected water produced when dewatering sludge. It consists of an efficient technology where less energy is supplied and no extra carbon source is added. However, it is unknown the efficiency of this system in terms of nitrous oxide production. For this reason, an analysis was carried out from the 19th June to the 2nd of July. In the light of the results obtained, the deammonification process has obtained better results than conventional nitrification and denitrification in terms of nitrous oxide emissions.
392

Toxicovigillance nehod s chemickými přípravky v domácnostech ČR / Toxicovigilance of accidents with household chemical products in the Czech Republic.

Mrázová, Karolina January 2015 (has links)
1 Abstract The aim of the study was to evaluate the numbers, severity and causes of accidents, occurring in the households due to the cleaning products. Among the groups of potentially dangerous cleaning products, the highest proportion of accidents was caused by cleaning products containing sodium hypochloride (37 %), descalers containing acids (29 %) and dishwasher tablets (25 %). A lower percentage of inquiries appeared due to hydroxides containing drain cleaning products (7 %). In the year 2009, there were 251 inquiries to the Toxicological Information Centre due to cleaning products in defined categories studied. Among them, there were 133 children and 118 adult patients, who ingested cleaning product accidentally (86%) or for suicidal purposes (3%); inhaled (9%) or had an eye contact with the product (2%). There were 23% children and 27% adults hospitalized; the children most frequently due to accidental ingestion of hydroxides (92%), the adults due to the inhalation of irritant vapors (64%). Among them 14% children (86% due to the ingestion of cleaning products containing hydroxides) have been examined using the endoscopy (in the total anesthesia), in addition to 5% adults. The study has shown that the most common cause of the accidents in children is the distraction of the adults; nevertheless, the...
393

Flight phenology of oligolectic solitary bees are affected by flowering phenology

Palm, Anna January 2021 (has links)
Understanding the relationships between solitary bees’ flight phenology and flowering phenology is important in the context of global warming. Using Swedish citizen science data, observations of oligolectic solitary bees and flowering phenology were used together with temperature data. All five bees studied had flight period that overlapped with the flowering period their corresponding host plant. None of the species were affected by the temperature, although there was a correlation between earliest observations of flowering phenology and flight phenology. The later the flowering observation was made, the later the flight observation was made. No correlation was found between the length of flight period and length of the flowering period. Increasing temperature is not the only factor that effects flight phenology and flowering phenology.
394

The effects of the macroalga Gracilaria gracilis and increasing temperatures on the performance of the endemic Cape eelgrass Zostera capensis

Beltrand, Maeva Mereana Marion January 2017 (has links)
Rising temperature caused by global warming alters physiology, phenology and/or distribution in a wide array of plant and animal species, which has dramatic knock-on effects at different levels of organisation. This study investigates the individual and interactive effects of temperature (18ᵒC, 22ᵒC and 30ᵒC) and additions of the macroalga Gracilaria gracilis (high and low) on the performance of the seagrass Zostera capensis, which occurs in Langebaan Lagoon, South Africa over a seven-week period. Results from the laboratory experiment revealed that G. gracilis did not significantly affect the performance of Z. capensis although temperature did result in greater leaf width, fouling and senescent biomass, as well as marginally greater leaf area and lower below-ground biomass at 30ᵒC. Increasing temperature also increased G. gracilis biomass, percent cover and fouling by microalgae. In addition, there was no interaction between temperature and the additions of Gracilaria. The overall findings of this study indicate that Z. capensis abundance is likely to decrease while G. gracilis will conversely increase in abundance in response to warming. Changes in abundance of those two ecosystem engineers highlight the possibility of a phase shift from a seagrass- to macroalgal-dominated state in Langebaan Lagoon.
395

Influence of Global Atmospheric Circulation Variations on Weather and Climate Extremes

Lin, Yen-Heng 01 August 2018 (has links)
Global warming and climate change deeply influence weather and climate extremes, causing substantial property damage and loss every year around the world. Given the importance of heating differences between low-latitude and Arctic regions, which produce heat sources and cold sources that each influence global circulations, we investigate three extreme weather events in different regions in order to better understand the possible connections between extreme events and global circulation changes. This study begins with climate variations in the low-latitude western North Pacific. In early summer, the timing of the wet season has shifted from late May to early June since 1979. This change influences the water supply in Southeast Asia. Our analysis results indicate that the increase in global temperatures is suggested to have induced this change. During the hurricane season, deep convection in the western North Pacific has a 20-year frequency of timing variations, oscillating between July and August and influencing hurricane activity. These variations have not been previously identified and do not have any driven forcings, but a precursor deep-convection signal is found in the spring. Mid-latitude weather and climate can be influenced by tropical deep convection through the Pacific North American teleconnection. Our analysis results suggest that the wintertime Californian drought is mainly modulated by a teleconnection pattern from the tropics and natural variations in North Pacific circulation. Another key factor that influences mid-latitude circulation is Arctic temperature variations. We find an increase in the subseasonal Arctic warming event, suggesting more weather extremes in the mid-latitudes. Evidence suggests that sea-ice loss and the increase in tropical deep convection results in the increased likelihood of a subseasonal Arctic warming event.
396

A Dynamic Analysis of the Global Timber Market and Carbon Flux of Forest under Global Warming: An Integrated Modeling Approach

Lee, Dug Man 01 May 2000 (has links)
As global warming migrates ecosystems toward the poles, the result has been a change in the distribution of ecosystem types and the productivity of ecosystem as well. Similar to other natural resources, forests are also potentially affected as ecosystems move toward the poles. Consequently, human beings are forced to adapt, and global warming will generate an impact on the global timber market through changes in timber harvests, regeneration inputs, stumpage prices, etc. In addition, the dynamic process of forest change in response to economic activities of human beings will accelerate or dampen the amount of carbon in the atmosphere. In this context, we propose an integrated modeling approach to identify the effect of global warming on the global timber market, and examine the feedback effect of the global timber market on global warming. To perform the primary research objective, we estimated dynamic ecological change based on (1) the simulation results of BIOME 3 using hamburg and (2) the linearity assumptions about change in climate and ecosystem. With the estimates of dynamic ecological change, we modified the Timber Supply Model 2000 (TSM 2000) to reflect the dynamic ecological change caused by climate change. After simulating the base scenario and the climate change scenario of TSM 2000, we identified that global warming has a positive effect on the global timber market. For the secondary research objective, we extend the modeling framework by incorporating the Terrestrial Carbon Model (TCM) designed to investigate net carbon release into the atmosphere. Simulating both the base TCM and the modified TCM which reflects climate change, we identified that the global timber market has a dampening (negative feedback) effect on global warming through net carbon sequestering. Fore sensitivity analyses, we performed these simulation procedures under three different timber demand growth scenarios
397

Early Life History Response of Reef Building Coral, Orbicella faveolata, to Ocean Acidification and Warming

Pitts, Kelly A 20 November 2018 (has links)
Ocean warming and acidification pose major threats to coral reef organisms. It is unknown how the early life history stages of Atlantic corals cope with the combined effects of these two global environmental stressors. Here, I investigate how these stressors influence the fertilization success, larval survivorship, and settlement of the threatened Atlantic coral, Orbicella faveolata. Gametes from O. faveolata were subjected to a factorial combination of present and future scenarios of oceanic temperatures (28.5° C and 30° C) and pH (8.2 and 8.0) predicted to occur by 2050. Results indicate that treatment type did not significantly affect fertilization success. Elevated temperature caused complete larval mortality and inhibited the settlement of O. faveolata. Interestingly, these negative effects of high temperature were partially mitigated when combined with ocean acidification. Overall, both the larval survivorship and settlement in the combined treatment was reduced to approximately half when compared to ambient treatment. Although ocean acidification may partially mitigate the negative effects of ocean warming during the larval stage, the overall reduced survival and settlement of larvae under future oceanic conditions, coupled to reduced calcification in adults, portends devastating effects on the health of this threatened species.
398

Feedbacks of Methane and Nitrous Oxide Emissions from Rice Agriculture

Sithole, Alec 01 January 2011 (has links)
The effect of global warming on methane (CH₄) and nitrous oxide (N₂O) emissions from agriculture was investigated and simulated from a soil warming experiment. Experiments were designed and installed in a temperature controlled greenhouse. The relationships between elevated temperatures and CH₄ and N₂O emissions were determined and calculated as the Q₁₀s of production, emission and oxidation. A study of the populations of methanogens and methanotrophs at a range of soil temperatures was performed based on soil molecular DNA analysis. This study showed that global warming would increase CH₄ emissions from rice agriculture and that the resultant emissions will be potentially large enough to cause changes in the present atmospheric concentrations. This research also showed that this increase was most evident for soil temperatures below 30⁰C, above which emissions decreased with increasing temperature. The seasonal average Q₁₀s of CH₄ emission, production, oxidation, methanogen and methanotroph populations were found to be 1.7, 2.6 and 2.2, 2.6 and 3.8, respectively, over a temperature of 20-32⁰C. Considering that the processes of CH₄ production and emission are similar to those in natural wetlands, which is the largest source of atmospheric CH₄, the contribution of this feedback is likely to cause a significant increase to the present CH₄ atmospheric budget if the current global warming trend persists over the next century. The Q₁₀s of N₂O emissions and production were 0.5-3.3 and 0.4-2.9, respectively. The low Q₁₀ values found for N₂O suggest that although global warming will have a direct impact on the production and emission rates. Nevertheless, the magnitude of the impact of global on both CH₄ and N₂O emissions from agriculture is likely to vary from one region to another due to the spatial variations in agricultural soil temperatures and the likely changes in the global regional distribution of water resources (water tables, rainfall patterns), water management practices and the responses of terrestrial CH₄ and N₂O sources such as natural wetlands and plants.
399

Estimating the Impacts of Climate Changes on Agricultural Productivities in Thailand, Using Simulation Models / シミュレーションモデルを用いた、タイにおける気候変動の農業生産性に及ぼす影響の推定

Yang, Boxuan 26 November 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21426号 / 農博第2304号 / 学位論文||H30||N5154(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 縄田 栄治, 教授 舟川 晋也, 教授 白岩 立彦 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM
400

Betydelsen av preoperativ uppvärmning för det perioperativa vårdförloppet : en litteraturöversikt / Preoperative warming and its effect on the perioperative period : a literature review

Nordin, Hanna January 2016 (has links)
Risken för perioperativ oavsiktlig hypotermi ökar i samband med anestesi. Redan vid uppkomsten av mild hypotermi riskerar patienten att drabbas av flertalet komplikationer, rörande bland annat koagulation och sårläkning. Vidare kan hypotermin bidra till uppkomsten av postoperativ shivering, vilket patienten ofta upplever som mycket obehagligt. Avsaknaden av nationella riktlinjer, kring hanteringen av oavsiktlig hypotermi, medför brist på stringens i det perioperativa uppvärmningsarbetet. Syfte: Syftet med studien var att belysa effekten av preoperativ uppvärmning för vuxna patienter under det perioperativa vårdförloppet. Metod: En integrativ litteraturöversikt skapades med utgångspunkt i fem sökord, vilka ansågs anknyta till studiens syfte och frågeställningar. Totalt 17 artiklar valdes ut och sammanställdes med hjälp av en integrativ analys. Resultat: Flertalet artiklar påvisade att preoperativ uppvärmning bidrog till en positivt förhöjd intraoperativ kärntemperatur. Vidare bidrog den preoperativa uppvärmningen till en ökad upplevelse av termal komfort och minskad oro under väntetiden inför operation. Slutsats: I likhet med flertalet internationella riktlinjer påvisade litteraturöversikten positiva effekter med preoperativ uppvärmning. Det åligger specialistsjuksköterskan att värna om den specifika omvårdnaden. Med hjälp av preoperativ uppvärmning kan specialistsjuksköterskan bidra till en tryggare och lugnare patient samt ett förbättrat perioperativt flöde med avseende på uppkomsten av oavsiktlig hypotermi.

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